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  • 1.
    Ahlberg, Martina
    et al.
    Univ Gothenburg, Dept Phys, S-41296 Gothenburg, Sweden..
    Chung, Sunjae
    Univ Gothenburg, Dept Phys, S-41296 Gothenburg, Sweden.;Korea Natl Univ Educ, Dept Phys Educ, Cheongju 28173, South Korea..
    Jiang, Sheng
    KTH, School of Engineering Sciences (SCI), Applied Physics. Univ Gothenburg, Dept Phys.
    Frisk, Andreas
    Univ Gothenburg, Dept Phys, S-41296 Gothenburg, Sweden..
    Khademi, Maha
    Shahid Beheshti Univ, Dept Phys, Tehran 1983969411, Iran..
    Khymyn, Roman
    Univ Gothenburg, Dept Phys, S-41296 Gothenburg, Sweden..
    Awad, Ahmad A.
    Univ Gothenburg, Dept Phys, S-41296 Gothenburg, Sweden..
    Le, Quang Tuan
    KTH, School of Engineering Sciences (SCI), Applied Physics. Univ Gothenburg, Dept Phys.
    Mazraati, Hamid
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics. NanOsc AB, S-16440 Kista, Sweden..
    Mohseni, Majid
    KTH, School of Engineering Sciences (SCI), Applied Physics. Shahid Beheshti Univ, Dept Phys, Tehran 1983969411, Iran..
    Weigand, Markus
    Max Planck Inst Intelligent Syst, Stuttgart, Germany..
    Bykova, Iuliia
    Max Planck Inst Intelligent Syst, Stuttgart, Germany..
    Gross, Felix
    Max Planck Inst Intelligent Syst, Stuttgart, Germany..
    Goering, Eberhard
    Max Planck Inst Intelligent Syst, Stuttgart, Germany..
    Schutz, Gisela
    Max Planck Inst Intelligent Syst, Stuttgart, Germany..
    Grafe, Joachim
    Max Planck Inst Intelligent Syst, Stuttgart, Germany..
    Åkerman, Johan
    KTH, School of Engineering Sciences (SCI), Applied Physics. Univ Gothenburg, Dept Phys.
    Freezing and thawing magnetic droplet solitons2022In: Nature Communications, E-ISSN 2041-1723, Vol. 13, no 1, article id 2462Article in journal (Refereed)
    Abstract [en]

    Magnetic droplets are a type of non-topological magnetic soliton, which are stabilised and sustained by spin-transfer torques for instance. Without this, they would collapse. Here Ahlberg et al show that by decreasing the applied magnetic field, droplets can be frozen, forming a static nanobubble Magnetic droplets are non-topological magnetodynamical solitons displaying a wide range of complex dynamic phenomena with potential for microwave signal generation. Bubbles, on the other hand, are internally static cylindrical magnetic domains, stabilized by external fields and magnetostatic interactions. In its original theory, the droplet was described as an imminently collapsing bubble stabilized by spin transfer torque and, in its zero-frequency limit, as equivalent to a bubble. Without nanoscale lateral confinement, pinning, or an external applied field, such a nanobubble is unstable, and should collapse. Here, we show that we can freeze dynamic droplets into static nanobubbles by decreasing the magnetic field. While the bubble has virtually the same resistance as the droplet, all signs of low-frequency microwave noise disappear. The transition is fully reversible and the bubble can be thawed back into a droplet if the magnetic field is increased under current. Whereas the droplet collapses without a sustaining current, the bubble is highly stable and remains intact for days without external drive. Electrical measurements are complemented by direct observation using scanning transmission x-ray microscopy, which corroborates the analysis and confirms that the bubble is stabilized by pinning.

  • 2.
    Ahmadi, Khadijeh
    et al.
    Shahid Beheshti Univ, Dept Phys, Tehran 19839, Iran.;Univ Tehran, Coll Engn, Adv Magnet Mat Res Ctr, Sch Met & Mat, Tehran 111554563, Iran..
    Mahfouzi, Farzad
    Calif State Univ Northridge, Dept Phys & Astron, Northridge, CA 91330 USA..
    Jamilpanah, Loghman
    Shahid Beheshti Univ, Dept Phys, Tehran 19839, Iran..
    Mohseni, Morteza
    Tech Univ Kaiserslautern, Fachbereich Phys & Landesforschungszentrum OPTIMA, D-67663 Kaiserslautern, Germany..
    Boettcher, Tobias
    Tech Univ Kaiserslautern, Fachbereich Phys & Landesforschungszentrum OPTIMA, D-67663 Kaiserslautern, Germany..
    Pirro, Philipp
    Tech Univ Kaiserslautern, Fachbereich Phys & Landesforschungszentrum OPTIMA, D-67663 Kaiserslautern, Germany..
    Kioussis, Nicholas
    Calif State Univ Northridge, Dept Phys & Astron, Northridge, CA 91330 USA..
    Åkerman, Johan
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics. ;Univ Gothenburg, Dept Phys, S-41296 Gothenburg, Sweden..
    Ebrahimi, S. A. Seyyed
    Univ Tehran, Coll Engn, Adv Magnet Mat Res Ctr, Sch Met & Mat, Tehran 111554563, Iran..
    Mohseni, Seyed Majid
    Shahid Beheshti Univ, Dept Phys, Tehran 19839, Iran..
    Inducing Dzyaloshinskii-Moriya interaction in symmetrical multilayers using post annealing2022In: Scientific Reports, E-ISSN 2045-2322, Vol. 12, no 1, article id 11877Article in journal (Refereed)
    Abstract [en]

    The interfacial Dzyaloshinskii-Moriya Interaction (iDMI) is an antisymmetric exchange interaction that is induced by the broken inversion symmetry at the interface of, e.g., a ferromagnet/heavy metal. Thus, the presence of iDMI is not expected in symmetrical multilayer stacks of such structures. Here, we use thermal annealing to induce the iDMI in a [Py/Pt](x10) symmetrical multilayer stack. Brillouin light scattering spectroscopy is used to directly evidence the iDMI induction in the annealed sample. Structural characterizations highlight the modified crystallinity as well as a higher surface roughness of the sample after annealing. First principles electronic structure calculations demonstrate a monotonic increase of the iDMI with the interfacial disorder due to the interdiffusion of atoms, depicting the possible origin of the induced iDMI. The presented method can be used to tune the iDMI strength in symmetric multilayers, which are the integral part of racetrack memories, magnonic devices as well as spin-orbitronic elements.

  • 3.
    Ahmadi, Mazaher
    et al.
    Bu Ali Sina Univ, Fac Chem, Hamadan, Iran..
    Moein, Mohammad Mahdi
    Karolinska Inst, Ctr Psychiat Res, Dept Clin Neurosci, SE-17176 Stockholm, Sweden.;Stockholm Cty Council, SE-17176 Stockholm, Sweden..
    Madrakian, Tayyebeh
    Bu Ali Sina Univ, Fac Chem, Hamadan, Iran..
    Afkhami, Abbas
    Bu Ali Sina Univ, Fac Chem, Hamadan, Iran..
    Bahar, Soleiman
    Univ Kurdistan, Fac Sci, Dept Chem, Sanandaj, Iran..
    Abdel-Rehim, Mohamed
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics. Karolinska Inst, Ctr Psychiat Res, Dept Clin Neurosci, SE-17176 Stockholm, Sweden.;Stockholm Cty Council, SE-17176 Stockholm, Sweden..
    Reduced graphene oxide as an efficient sorbent in microextraction by packed sorbent: Determination of local anesthetics in human plasma and saliva samples utilizing liquid chromatography-tandem mass spectrometry2018In: Journal of chromatography. B, ISSN 1570-0232, E-ISSN 1873-376X, Vol. 1095, p. 177-182Article in journal (Refereed)
    Abstract [en]

    Herein, reduced graphene oxide (RGO) has been utilized as an efficient sorbent in microextraction by packed sorbent (MEPS). The combination of MEPS and liquid chromatography-tandem mass spectrometry has been used to develop a method for the extraction and determination of three local anesthetics (i.e. lidocaine, prilocaine, and ropivacaine) in human plasma and saliva samples. The results showed that the utilization of RGO in MEPS could minimize the matrix effect so that no interfering peaks at the retention times of the analytes or internal standard was observed. The high extraction efficiency of this method was approved by mean recoveries of 97.26-106.83% and 95.21-105.83% for the studied analytes in plasma and saliva samples, respectively. Intra- and inter-day accuracies and precisions for all analytes were in good accordance with the international regulations. The accuracy values (as percentage deviation from the nominal value) of the quality control samples were between - 2.1 to 13.9 for lidocaine, - 4.2 to 11.0 for prilocaine and between - 4.5 to - 2.4 for ropivacaine in plasma samples while the values were ranged from - 4.6 to 1.6 for lidocaine, from - 4.2 to 15.5 for prilocaine and from - 3.3 to - 2.3 for ropivacaine in human saliva samples. Lower and upper limit of quantification (LLOQ, ULOQ) were set at 5 and 2000 nmol L-1 for all of the studied drugs. The correlation coefficients values were >= 0.995. The limit of detection values were obtained 4 nmol L-1 for lidocaine and prilocaine, and 2 nmol L-1 for ropivacaine.

  • 4.
    Al Soubaihi, Rola Mohammad
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Saoud, Khaled Mohammad
    Virginia Commonwealth Univ Qatar, Liberal Arts & Sci Program, Doha, Qatar..
    Myint, Myo Tay Zar
    Sultan Qaboos Univ, Coll Sci, Dept Phys, POB 36, Muscat 123, Oman..
    Göthelid, Mats A.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    CO Oxidation Efficiency and Hysteresis Behavior over Mesoporous Pd/SiO2 Catalyst2021In: Catalysts, E-ISSN 2073-4344, Vol. 11, no 1, article id 131Article in journal (Refereed)
    Abstract [en]

    Carbon monoxide (CO) oxidation is considered an important reaction in heterogeneous industrial catalysis and has been extensively studied. Pd supported on SiO2 aerogel catalysts exhibit good catalytic activity toward this reaction owing to their CO bond activation capability and thermal stability. Pd/SiO2 catalysts were investigated using carbon monoxide (CO) oxidation as a model reaction. The catalyst becomes active, and the conversion increases after the temperature reaches the ignition temperature (T-ig). A normal hysteresis in carbon monoxide (CO) oxidation has been observed, where the catalysts continue to exhibit high catalytic activity (CO conversion remains at 100%) during the extinction even at temperatures lower than T-ig. The catalyst was characterized using BET, TEM, XPS, TGA-DSC, and FTIR. In this work, the influence of pretreatment conditions and stability of the active sites on the catalytic activity and hysteresis is presented. The CO oxidation on the Pd/SiO2 catalyst has been attributed to the dissociative adsorption of molecular oxygen and the activation of the C-O bond, followed by diffusion of adsorbates at T-ig to form CO2. Whereas, the hysteresis has been explained by the enhanced stability of the active site caused by thermal effects, pretreatment conditions, Pd-SiO2 support interaction, and PdO formation and decomposition.

  • 5. Al-Abri, M.
    et al.
    Al-Ghafri, B.
    Bora, T.
    Dobretsov, S.
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Castelletto, S.
    Rosa, L.
    Boretti, A.
    Chlorination disadvantages and alternative routes for biofouling control in reverse osmosis desalination2019In: npj Clean Water, ISSN 2059-7037, Vol. 2, no 1, article id 2Article in journal (Refereed)
    Abstract [en]

    With an ever-increasing human population, access to clean water for human use is a growing concern across the world. Seawater desalination to produce usable water is essential to meet future clean water demand. Desalination processes, such as reverse osmosis and multi-stage flash have been implemented worldwide. Reverse osmosis is the most effective technology, which uses a semipermeable membrane to produce clean water under an applied pressure. However, membrane biofouling is the main issue faced by such plants, which requires continuous cleaning or regular replacement of the membranes. Chlorination is the most commonly used disinfection process to pretreat the water to reduce biofouling. Although chlorination is widely used, it has several disadvantages, such as formation of disinfection by-products and being ineffective against some types of microbes. This review aims to discuss the adverse effect of chlorination on reverse osmosis membranes and to identify other possible alternatives of chlorination to reduce biofouling of the membranes. Reverse osmosis membrane degradation and mitigation of chlorines effects, along with newly emerging disinfection technologies, are discussed, providing insight to both academic institutions and industries for the design of improved reverse osmosis systems. 

  • 6.
    Albertsson, Dagur Ingi
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electronics and Embedded systems, Integrated devices and circuits.
    Zahedinejad, Mohammad
    Department of Physics, University of Gothenburg.
    Åkerman, Johan
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics. Department of Physics, University of Gothenburg.
    Rodriguez, Saul
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electronics and Embedded systems, Integrated devices and circuits.
    Rusu, Ana
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electronics and Embedded systems, Integrated devices and circuits.
    Compact Macrospin-Based Model of Three-Terminal Spin-Hall Nano Oscillators2019In: IEEE transactions on magnetics, ISSN 0018-9464, E-ISSN 1941-0069, Vol. 55, no 10, article id 4003808Article in journal (Refereed)
    Abstract [en]

    Emerging spin-torque nano oscillators (STNOs) and spin-Hall nano oscillators (SHNOs) are potential candidates for microwave applications. Recent advances in three-terminal magnetic tunnel junction (MTJ)-based SHNOs opened the possibility to develop more reliable and well-controlled oscillators, thanks to individual spin Hall-driven precession excitation and read-out paths. To develop hybrid systems by integrating three-terminal SHNOs and CMOS circuits, an electrical model able to capture the analog characteristics of three-terminal SHNOs is needed. This model needs to be compatible with current electric design automation (EDA) tools. This work presents a comprehensive macrospin-based model of three-terminal SHNOs able to describe the dc operating point, frequency modulation, phase noise, and output power. Moreover, the effect of voltage-controlled magnetic anisotropy (VCMA) is included. The model shows good agreement with experimental measurements and could be used in developing hybrid three-terminal SHNO/CMOS systems.

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  • 7.
    Alexander, Gerianne
    et al.
    Texas A&M Univ, Dept Psychol & Brain Sci, College Stn, TX USA..
    Allen, Roland E.
    Texas A&M Univ, Dept Phys & Astron, College Stn, TX 77843 USA..
    Atala, Anthony
    Wake Forest Inst Regenerat Med, 391 Technol Way, Winston Salem, NC 27157 USA..
    Bowen, Warwick P.
    Univ Queensland, Sch Math & Phys, St Lucia, Qld 4072, Australia.;Univ Queensland, Australian Ctr Engn Quantum Syst, St Lucia, Qld 4072, Australia..
    Coley, Alan A.
    Dalhousie Univ, Dept Math & Stat, Halifax, NS B3H 4R2, Canada..
    Goodenough, John B.
    Univ Texas Austin, Cockrell Inst, Walker Dept Mech Engn, Austin, TX 78712 USA..
    Katsnelson, Mikhail, I
    Radboud Univ Nijmegen, Inst Mol & Mat, NL-6525 AJ Nijmegen, Netherlands..
    Koonin, Eugene, V
    Natl Lib Med, Natl Ctr Biotechnol Informat, Bethesda, MD 20894 USA..
    Krenn, Mario
    Austrian Acad Sci, Inst Quantum Opt & Quantum Informat IQOQI, Boltzmanngasse 3, A-1090 Vienna, Austria.;Univ Toronto, Dept Chem, Toronto, ON, Canada..
    Madsen, Lars S.
    Univ Queensland, Australian Ctr Engn Quantum Syst, St Lucia, Qld 4072, Australia..
    Månsson, Martin
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Mauranyapin, Nicolas P.
    Univ Queensland, Sch Math & Phys, St Lucia, Qld 4072, Australia..
    Melvin, Art, I
    Austrian Acad Sci, Inst Quantum Opt & Quantum Informat IQOQI, Boltzmanngasse 3, A-1090 Vienna, Austria.;Univ Vienna, Fac Phys, Vienna Ctr Quantum Sci & Technol VCQ, Boltzmanngasse 5, A-1090 Vienna, Austria..
    Rasel, Ernst
    Inst Quantenopt, Welfengarten 1, D-30167 Hannover, Germany.;Leibnitz Univ Hannover, QUEST LFS DLR Inst Satellite Geodesy & Inertial S, Welfengarten 1, D-30167 Hannover, Germany..
    Reichl, Linda E.
    Univ Texas Austin, Ctr Complex Quantum Syst, Austin, TX 78712 USA.;Univ Texas Austin, Dept Phys, Austin, TX 78712 USA..
    Yampolskiy, Roman
    Univ Louisville, Duthie Ctr Engn, Dept Comp Engn & Comp Sci, Louisville, KY 40292 USA..
    Yasskin, Philip B.
    Texas A&M Univ, Dept Math, College Stn, TX 77843 USA..
    Zeilinger, Anton
    Austrian Acad Sci, Inst Quantum Opt & Quantum Informat IQOQI, Boltzmanngasse 3, A-1090 Vienna, Austria.;Univ Vienna, Fac Phys, Vienna Ctr Quantum Sci & Technol VCQ, Boltzmanngasse 5, A-1090 Vienna, Austria..
    Lidstrom, Suzy
    Texas A&M Univ, Dept Phys & Astron, College Stn, TX 77843 USA..
    The sounds of science-a symphony for many instruments and voices2020In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 95, no 6, article id 062501Article in journal (Refereed)
    Abstract [en]

    Sounds of Science is the first movement of a symphony for many (scientific) instruments and voices, united in celebration of the frontiers of science and intended for a general audience. John Goodenough, the maestro who transformed energy usage and technology through the invention of the lithium-ion battery, opens the programme, reflecting on the ultimate limits of battery technology. This applied theme continues through the subsequent pieces on energy-related topics-the sodium-ion battery and artificial fuels, by Martin Mansson-and the ultimate challenge for 3D printing, the eventual production of life, by Anthony Atala. A passage by Gerianne Alexander follows, contemplating a related issue: How might an artificially produced human being behave? Next comes a consideration of consciousness and free will by Roland Allen and Suzy Lidstrom. Further voices and new instruments enter as Warwick Bowen, Nicolas Mauranyapin and Lars Madsen discuss whether dynamical processes of single molecules might be observed in their native state. The exploitation of chaos in science and technology, applications of Bose-Einstein condensates and the significance of entropy follow in pieces by Linda Reichl, Ernst Rasel and Roland Allen, respectively. Mikhail Katsnelson and Eugene Koonin then discuss the potential generalisation of thermodynamic concepts in the context of biological evolution. Entering with the music of the cosmos, Philip Yasskin discusses whether we might be able to observe torsion in the geometry of the Universe. The crescendo comes with the crisis of singularities, their nature and whether they can be resolved through quantum effects, in the composition of Alan Coley. The climax is Mario Krenn, Art Melvin and Anton Zeilinger's consideration of how computer code can be autonomously surprising and creative. In a harmonious counterpoint, his 'Guidelines for considering AIs as coauthors', Roman Yampolskiy concludes that code is not yet able to take responsibility for coauthoring a paper. An interlude summarises a speech by Zdenek Papousek. In a subsequent movement, new themes emerge as we seek to comprehend how far we have travelled along the path to understanding, and speculate on where new physics might arise. Who would have imagined, 100 years ago, a global society permeated by smartphones and scientific instruments so sophisticated that genes can be modified and gravitational waves detected?

  • 8. Al-Naamani, Laila
    et al.
    Muthukrishnan, Thirumahal
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Dobretsov, Sergey
    Antifouling properties or chitosan coatings on plastic substrates2019In: Journal of Agricultural and Marine Sciences, ISSN 2410-1060, Vol. 23, no 1, p. 92-98Article in journal (Refereed)
  • 9. Al-Saadi, Mubarak J.
    et al.
    Al-Harthi, Salim H.
    Kyaw, Htet H.
    Myint, Myo T. Z.
    Bora, Tanujjal
    Laxman, Karthik
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Al-Hinai, Ashraf
    Dutta, Joydeep
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Influence of Atomic Hydrogen, Band Bending, and Defects in the Top Few Nanometers of Hydrothermally Prepared Zinc Oxide Nanorods2017In: Nanoscale Research Letters, ISSN 1931-7573, E-ISSN 1556-276X, Vol. 12, article id 22Article in journal (Refereed)
    Abstract [en]

    We report on the surface, sub-surface (top few nanometers) and bulk properties of hydrothermally grown zinc oxide (ZnO) nanorods (NRs) prior to and after hydrogen treatment. Upon treating with atomic hydrogen (H*), upward and downward band bending is observed depending on the availability of molecular H2O within the structure of the NRs. In the absence of H2O, the H* treatment demonstrated a cleaning effect of the nanorods, leading to a 0.51 eV upward band bending. In addition, enhancement in the intensity of room temperature photoluminescence (PL) signals due to the creation of new surface defects could be observed. The defects enhanced the visible light activity of the ZnO NRs which were subsequently used to photocatalytically degrade aqueous phenol under simulated sunlight. On the contrary, in the presence of H2O, H* treatment created an electronic accumulation layer inducing downward band bending of 0.45 eV (similar to 1/7th of the bulk ZnO band gap) along with the weakening of the defect signals as observed from room temperature photoluminescence spectra. The results suggest a plausible way of tailoring the band bending and defects of the ZnO NRs through control of H2O/H* species.

  • 10.
    Al-Soubaihi, Rola
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Saoud, Khaled Mohammad
    Virginia Commonwealth Univ Qatar, Liberal Arts & Sci Program, POB 8095, Doha, Qatar..
    Awadallah-F, Ahmed
    Qatar Univ, Dept Chem Engn, POB 2713, Doha, Qatar..
    Elkhatat, Ahmed Mohamed
    Qatar Univ, Dept Chem Engn, POB 2713, Doha, Qatar..
    Al-Muhtaseb, Shaheen A.
    Qatar Univ, Dept Chem Engn, POB 2713, Doha, Qatar..
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Investigation of palladium catalysts in mesoporous silica support for CO oxidation and CO2 adsorption2023In: Heliyon, E-ISSN 2405-8440, Vol. 9, no 7, article id e18354Article in journal (Refereed)
    Abstract [en]

    The oxidation of Carbon monoxide (CO) to Carbon dioxide (CO2) is one of the most extensively investigated reactions in the field of heterogeneous catalysis, and it occurs via molecular rearrangements induced by catalytic metal atoms with oxygen intermediates. CO oxidation and CO2 capture are instrumental processes in the reduction of green-house gas emissions, both of which are used in low-temperature CO oxidation in the catalytic converters of vehicles. CO oxidation and CO2 adsorption at different temperatures are evaluated for palladium-supported silica aerogel (Pd/SiO2). The synthesized catalyst was active and stable for low-temperature CO oxidation. The catalytic activity was enhanced after the first cycle due to the reconditioning of the catalyst's pores. It was found that the presence of oxide forms of palladium in the SiO2 microstructure, influences the performance of the catalysts due to oxygen vacancies that increases the frequency of active sites. CO2 gas adsorption onto Pd/SiO2 was investigated at a wide-ranging temperature from 16 to 120 degrees C and pressures similar to 1 MPa as determined from the isotherms that were evaluated, where CO2 showed the highest equilibrium adsorption capacity at 16 degrees C. The Langmuir model was employed to study the equilibrium adsorption behavior. Finally, the effect of moisture on CO oxidation and CO2 adsorption was considered to account for usage in real-world applications. Overall, mesoporous Pd/SiO2 aerogel shows potential as a material capable of removing CO from the environment and capturing CO2 at low temperatures.

  • 11.
    Al-Soubaihi, Rola
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Saoud, Khaled Mohammad
    Virginia Commonwealth Univ Qatar, Liberal Arts & Sci Program, POB 8095, Doha, Qatar..
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Comparative investigation of structure and operating parameters on the performance and reaction dynamic of CO conversion on silica aerogel and fumed-silica-supported Pd catalysts2022In: SURFACES AND INTERFACES, ISSN 2468-0230, Vol. 29, p. 101776-, article id 101776Article in journal (Refereed)
    Abstract [en]

    The catalyst morphology, metal-support interaction, and reaction conditions greatly influence the catalytic performance and reaction dynamics. Similarly, the dispersion of the metal within the support plays a crucial in the thermal stability and sintering of the catalyst. Furthermore, temperature-dependent conversion hysteresis is well-known to occur during ignition and extinction of exothermic CO oxidation over supported Pd catalysts due to the variation of CO adsorption on the surface or bulk oxidation of Pd and the ability of the catalyst regenerate the active sites. Herein, the catalytic performance and the hysteresis behavior of mesoporous silica aerogel supported Pd (Pd/a-SiO2), and commercial fumed silica-supported Pd (Pd/f-SiO2) were investigated compared using CO oxidation as a probe reaction under different reaction conditions and operating parameters (i.e., catalyst weight, ramp rate, and flow rate). Surface and morphologic examination using XPS, FTIR, and of Pd/a-SiO2 and Pd/f-SiO2 reveal a strong correlation between the catalyst surface and structure and its catalytic performance and stability under different reaction parameters. Moreover, this study presents the effect of surface area, particle size, and size distribution on diffusion and mass transport of reactants (CO, O-2) and products (CO2) and active sites accessibility. This study showed that Pd/f-SiO2 had better efficiency under high (turbulence) flow. Moreover, intrinsic apparent activation energy (E-a) and the number of active sites were calculated from the Kinetics of CO oxidation fitted using Arrhenius plots indicate that the ramp rate has less effect on Pd/f-SiO2 catalytic behavior. though, Pd/f-SiO2 had higher relative active sites than Pd/a-SiO2, (E-a) was lower. Cyclic stability and long-term stabilities showed that both catalysts are stable and can regenerate the active sites. The current study contributes to understanding the catalysts' surface, structural and morphological properties on the catalysts' performance toward CO oxidation and other reactions under dynamic conditions.

  • 12.
    Al-Soubaihi, Rola
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Saoud, Khaled Mohammad
    Virginia Commonwealth Univ Qatar, Liberal Arts & Sci Program, POB 8095, Doha, Qatar..
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Low-temperature CO oxidation by silver nanoparticles in silica aerogel mesoreactors2023In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 455, p. 140576-, article id 140576Article in journal (Refereed)
    Abstract [en]

    Low-temperature carbon monoxide (CO) oxidation on silver/silica aerogel (Ag/SiO2 AG) catalyst prepared by one-pot sol-gel synthesis followed by supercritical ethanol drying method is reported. Highly stable and sinterproof catalyst led to easy reactant diffusion to the active sites. The Ag/SiO2 AG catalyst showed enhanced catalytic activity toward low-temperature CO oxidation by preventing agglomeration of silver nanoparticles inside pores and facilitating well-dispersed active sites to enhance the mass heat transfer in the mesopores. Catalyst pretreatment conditions were found to play a crucial role in achieving high CO conversion efficiency at low light-off temperatures. Inverse counter-clockwise CO oxidation hysteresis was found to occur after the first run. The active sites contributing to this enhanced catalytic behavior were confirmed to be Ag0 from XPS, XRD, and TEM analysis. The catalyst exhibited good thermal stability up to 450 degrees C over repeated number of cycles.

  • 13.
    Alvarado Ávila, María Isabel
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Toledo-Carrillo, Esteban Alejandro
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Cerium Oxide on a Fluorinated Carbon-Based Electrode as a Promising Catalyst for Hypochlorite Production2022In: ACS Omega, E-ISSN 2470-1343, Vol. 7, no 42, p. 37465-37475Article in journal (Refereed)
    Abstract [en]

    Sodium hypochlorite (NaOCl) is widely used as a disinfectant agent for water treatment and surface cleaning. A straightforward way to produce NaOCl is by the electrolysis of an aqueous sodium chloride (NaCl) solution. This process presents several side reactions decreasing its efficiency with hypochlorite reduction on the cathode surface being one of the main detrimental reactions. In this work, we have studied carbon-based electrodes modified with cerium oxide (CeO2), fluorine, and platinum nanoparticles as cathodes for hypochlorite production. Fluorination was carried out electrochemically; the polyol method was used to synthesize platinum nanoparticles; and the hydrothermal process was applied to form a CeO2 layer. Scanning electron microscopy, FTIR, and inductively coupled plasma (ICP) indicated the presence of cerium oxide as a film, fluorine groups on the substrate, and a load of 3.2 mg/cm2 of platinum nanoparticles and 2.7 mg/cm2 of CeO2. From electrochemical impedance spectroscopy, it was possible to demonstrate that incorporating platinum and fluorine decreases the charge transfer resistance by 16% and 28%, respectively. Linear sweep voltammetry showed a significant decrease in hypochlorite reduction when the substrate was doped with fluorine from -16.6 mA/cm2 at -0.6 V to -9.64 mA/cm2 that further reduced to -8.78 mA/cm2 with cerium oxide covered fluorinated electrodes. The performance of the cathode materials during hypochlorite production improved by 80% compared with pristine activated carbon cloth (ACC) electrodes. The improvement toward hindering NaOCl reduction is probably caused by the incorporation of a partial negative charge upon doping with fluorine.

  • 14.
    Alvarado Ávila, María Isabel
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics. KTH, School of Biotechnology (BIO), Centres, Albanova VinnExcellence Center for Protein Technology, ProNova.
    Toledo-Carrillo, Esteban Alejandro
    KTH, School of Biotechnology (BIO), Centres, Albanova VinnExcellence Center for Protein Technology, ProNova. KTH, School of Engineering Sciences (SCI), Applied Physics.
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics. KTH, School of Biotechnology (BIO), Centres, Albanova VinnExcellence Center for Protein Technology, ProNova.
    Improved chlorate production with platinum nanoparticles deposited on fluorinated activated carbon cloth electrodes2020In: Cleaner Engineering and Technology, ISSN 2666-7908, Vol. 1, article id 100016Article in journal (Refereed)
    Abstract [en]

    Sodium chlorate is one of the main oxidizing agents used in the wood industry due to their capability of use as an elemental chlorine-free (CEF) bleaching. A simple way to produce chlorates is by the electrolysis of an aqueous sodium chloride (NaCl) solution. In the present study activated carbon cloth electrodes (ACC) modified with fluorine and platinum nanoparticles (Pt–F/ACC and Pt/ACC) were used as one of the electrodes. Electrofluorination was used for fluorination of the anodes and polyol method was used for the synthesis of platinum nanoparticles. Chlorate production using a typical solution of 100 ​g/l of sodium chloride (NaCl) and 2 ​g/l sodium chromate (Na2Cr2O7) and an applied current of 0.540 ​A was studied. Prior to the electrolysis assays, the microstructural properties of the electrodes were characterized by scanning electron microscopy and surface modifications and bonding using infra-red (FTIR) spectroscopy. Electrochemical properties were determined using cyclic voltammetry (CV), linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques. Interaction between fluorine (F) and platinum (Pt) on the electrode leads to an improvement of the electrocatalytic properties for chlorine evolution as observed from the increase in the current efficiency from 37.5% at 78.5% after 150 ​min of continuous electrolysis using Pt–F/ACC anodes. The results suggest that modified activated carbon material is an attractive and economical alternative as electrodes for chlorate production. 

  • 15. Andersen, J.
    et al.
    Tavares, P. F.
    Isaksson, L.
    Kotur, M.
    Lindau, F.
    Mansten, E.
    Olsson, D.
    Tarawneh, H.
    Thorin, S.
    Curbis, F.
    Werin, S.
    Goryashko, V.
    Bonetti, S.
    Larsson, M.
    Nilsson, A.
    Salén, P.
    Johnsson, P.
    Tjernberg, Oscar
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    The soft X-ray laser project at MAX IV2017In: IPAC 2017 - Proceedings of the 8th International Particle Accelerator Conference, Joint Accelerator Conferences Website - JACoW , 2017, p. 2760-2762Conference paper (Refereed)
    Abstract [en]

    A Soft X-ray Laser (SXL) beamline utilising FEL technology is being designed for the Short Pulse Facility (SPF) at the MAX IV Laboratory. A conceptual design study has been started following on the scientific case already prepared in collaboration between several Swedish Universities and driven by a strong (Swedish) user demand. The baseline goal of the SXL beamline is to generate intense and short pulses in the range 1-5 nm (0.2-1 keV). The system is building on the MAX IV linac system, already today providing 100 fs 3 GeV and pulses compressed to 100 fs for other applications within the SPF. As a special feature we foresee a variety of pump-probe capabilities. 

  • 16.
    Andersson, Magnus
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Hur får vi studenter i grundläggande kurser att lägga ned det arbete som krävs?2020In: Bidrag från 7:e Utvecklingskonferensen för Sveriges ingenjörsutbildningar / [ed] Lennart Pettersson och Karin Bolldén, 2020, p. 203-204Conference paper (Refereed)
    Abstract [sv]

    Jag och mina kollegor upplever att många studenter idag inte går på föreläsningar eller deltar i annan undervisning på grundkurser. När de sedan efter kursens slut tillfrågas hur många timmar de har lagt ned på densamma, är det många som anger ett timantal som ligger under det som förväntas av dem enligt kursens poängtal. Samtidigt ser vi att tentamensresultaten försämras. Detta leder i sin tur till en låg genomströmning eller i allra värsta fall till att kurskraven sänks. Här visar jag ett illustrativa exempel på hur kursaktivitet korrelarar med tentamensresultat, redovisar vad jag har funnit i forskningslitteraturen om detta samt ställer frågan vad vi som lärare bör göra för att förbättra situationen.

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  • 17.
    Andersson, Magnus
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Networking change leader - a new role for a program director in engineering education2023In: Proceedings of the 19th International CDIO Conference / [ed] Reidar Lyng, Jens Bennedsen, Lamjed Bettaieb, Runde Bodsberg, Kristina Edström, Maria Sigridur Gudjonsdottir, Janne Roslöf, Ole K. Solbjörg, Geir Öein, Trondheim: NTNU SEED , 2023, p. 669-678Conference paper (Refereed)
    Abstract [en]

    Calls for changes in higher education are omnipresent and motivated by major challenges for society. Several of these challenges, for example those related to digitalization and sustainability, falls into the category of emerging and transformative challenges. The breadth and width of such challenges is too large to be handled by a single individual or even a small group of individuals. Instead, their solution requires an adaptive leadership with relevant activities at all organizational levels. From research literature and previous successful change processes, it is known that change leaders in the middle are key players during such transformations. In engineering education (and in fact in any other education aiming for a profession), it is natural that this role is taken by a program director who already has a responsibility for the quality and the development of an engineering program.  In this work, I will approach the role of a program director from a logical perspective using arguments based on a simple comparison between available time and total time required to create the desired change. It is obvious that large challenges demand a substantial amount of time to find an acceptable solution, which is outside of the reach for any single individual, I will also discuss the crucial role of persons in the middle for obtaining successful change related to large challenges. Finally, I will also try to give some answers to the question how a program director in the role as a person in the middle can survive in this pressing situation. I will point towards the needs for some competence in agile change management, the ability to create structures and collaborative efforts that promote agile actions, the need for making coherence and using inclusion strategies and the necessity of networking. I will also emphasize the importance that universities support internal and external networking structures.

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    CDIO2023-PA-work
  • 18.
    Andersson, Magnus
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Networking Change Leader: New Role for a Program Director in Engineering Education2023In: 19th CDIO International Conference, CDIO 2023 - Proceedings, Chalmers University of Technology , 2023, p. 669-678Conference paper (Refereed)
    Abstract [en]

    Calls for changes in higher education are omnipresent and motivated by major challenges for society. Several of these challenges, for example those related to digitalization and sustainability, falls into the category of emerging and transformative challenges. The breadth and width of such challenges is too large to be handled by a single individual or even a small group of individuals. Instead, their solution requires an adaptive leadership with relevant activities at all organizational levels. From research literature and previous successful change processes, it is known that change leaders in the middle are key players during such transformations. In engineering education (and in fact in any other education aiming for a profession), it is natural that this role is taken by a program director who already has a responsibility for the quality and the development of an engineering program. In this work, I will approach the role of a program director from a logical perspective using arguments based on a simple comparison between available time and total time required to create the desired change. It is obvious that large challenges demand a substantial amount of time to find an acceptable solution, which is outside of the reach for any single individual. I will also discuss the crucial role of persons in the middle for obtaining successful change related to large challenges. Based on my own case, I will try to give some advice about how a program director in the role as a person in the middle can handle this pressing situation. I will point towards the needs of personal time management, a basic understanding of agile change management, the ability to create structures and collaborative efforts that promote agile actions, the need for making coherence and using inclusion strategies and the necessity of networking. I will also emphasize the importance that universities support internal and external networking structures.

  • 19.
    Andersson, Magnus
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Non-proctored home exams - is there a solution?2022In: Bidrag från 8:e Utvecklingskonferensen för Sveriges ingenjörsutbildningar / [ed] Helena Håkansson, Karlstad, 2022, p. 143-144Conference paper (Refereed)
    Abstract [en]

    Restrictions during the pandemic has forced teachers to replace traditional classroom exams with home exams, which are either proctored by digital tools or non-proctored. In this work, I describe the student response from using non-proctored digital home exams in two university courses in physics. In particular, the advantages and disadvantages of this approach will be discussed, since there are major concern about grading students based on non-proctored exams due to issues related to authenticity and cheating. Finally, I will reflect on the future use of non- proctored exams to evaluate knowledge in physics.

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  • 20.
    Andersson, Magnus
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Delin, Anna
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    A quality process for assessing mathematics in a study programme2018In: Proceedings från 6:e utvecklingskonferensen för Sveriges ingenjörsutbildningar / [ed] Lena Petersson, Kristina Edström, Oskar Gedda, Fredrik Georgsson, Liselott Lycke och Marie Arehag, 2018Conference paper (Refereed)
    Abstract [en]

    We present two methodologies to assess the use of mathematics in a study programme. Firstly, we use a relatively simple methodology to assess how students show their ability to use mathematics in their degree project reports. Secondly, we present a methodology to assess how mathematics is used during a study programme. We have applied the first methodology on the mathematics content in 114 randomly chosen bachelor degree reports from 6 different study programmes within the fields of electrical engineering and computer engineering at KTH. For the 3-year bachelor degree programmes in computer engineering, we find clear deficits in the way students use mathematics in their bachelor degree reports as compared to the other programmes in our study. Through the second methodology, we were able to relate the deficits in the bachelor degree reports to a programme structure where skills in mathematics have not been sufficiently demanded in the engineering courses of the programme. 

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  • 21.
    Andersson, Magnus
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Karlander, Johan
    KTH, School of Electrical Engineering and Computer Science (EECS), Computer Science, Theoretical Computer Science, TCS.
    Sandberg, Mattias
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Numerical Analysis, NA.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics.
    Admission to master programmes: What are the indicators for successful study performance?2023In: Bidrag från den 9:e utvecklingskonferensen för Sveriges ingenjörsutbildningar / [ed] Joel Midemalm, Amir Vadiee, Elisabeth Uhlemann, Fredrik Georgsson, Gunilla Carlsson-Kvarnlöf, Jonas Månsson, Kristina Edström, Lennart Pettersson och Pedher Johansson, Västerås: Mälardalens universitet, 2023, p. 9-18Conference paper (Refereed)
    Abstract [en]

    Admission of applicants to higher education in a fair, reliable, transparent, and efficient way is a real challenge, especially if there are more eligible applicants than available places and if there are applicants from many different educational systems. Previous research on best practices for admission to master’s programmes identified the key question about an applicant’s potential for success in studies, but was not able to provide an answer about how to rate the merits of the applicants. In this study, indicators for study success are analysed by comparing the study performance of 228 students in master’s programmes with their merits at the time of admission. The null hypothesis was that the applicant’s average grade at the time of admission is the only indictor for study success. After testing for potential bias using almost 20 possible other indicators, the null hypothesis had to be rejected for four indicators (in order of importance): (i) university ranking, (ii) length of bachelor’s studies within subject, (iii) English language test and (iv) subject matching between bachelor’s and master’s education. Evaluation of quality of prior education is tricky and results from this study clearly indicate that students from higher ranked universities possess better knowledge and stronger skills for our master’s programmes. Work is ongoing to improve the merit rating model by involving more master’s programmes at KTH and analysing performance data from a larger number of students.

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    Master-admission
  • 22.
    Andersson, Magnus
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Weurlander, Maria
    KTH, School of Industrial Engineering and Management (ITM), Learning.
    Peer review of laboratory reports for engineering students2018In: European Journal of Engineering Education, ISSN 0304-3797, E-ISSN 1469-5898, p. 1-12Article in journal (Refereed)
    Abstract [en]

    Here, we present a module to introduce student peer review of laboratoryreports to engineering students. Our findings show that students werepositive and felt that they had learnt quite a lot from this experience.The most important part of the module was the classification scheme.The scheme was constructed to mimic the way an expert would arguewhen making a fair judgement of a laboratory report. Hence, our resultsmay suggest that the success of the module design comes from activelyengaging students in work that is more related to ‘arguing like anexpert’ than to only supply feedback to peers, which in such a casewould implicate a somewhat new direction for feedback research. Forpractitioners, our study suggests that important issues to consider in thedesign are (i) a clear and understandable evaluation framework, (ii)anonymity in the peer-review process and (iii) a small external motivation.

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  • 23.
    Awad, Ahmad A.
    et al.
    Univ Gothenburg, Dept Phys, S-41296 Gothenburg, Sweden.;Univ Gothenburg, Dept Phys, S-41296 Gothenburg, Sweden..
    Houshang, Afshin
    Univ Gothenburg, Dept Phys, S-41296 Gothenburg, Sweden.;Univ Gothenburg, Dept Phys, S-41296 Gothenburg, Sweden..
    Zahedinejad, Mohammad
    Univ Gothenburg, Dept Phys, S-41296 Gothenburg, Sweden.;Univ Gothenburg, Dept Phys, S-41296 Gothenburg, Sweden..
    Khymyn, Roman
    Univ Gothenburg, Dept Phys, S-41296 Gothenburg, Sweden.;Univ Gothenburg, Dept Phys, S-41296 Gothenburg, Sweden..
    Åkerman, Johan
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics. Univ Gothenburg, Dept Phys, S-41296 Gothenburg, Sweden.
    Width dependent auto-oscillating properties of constriction based spin Hall nano-oscillators2020In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 116, no 23, article id 232401Article in journal (Refereed)
    Abstract [en]

    We study the current tunable microwave signal properties of nano-constriction-based spin Hall nano-oscillators in oblique magnetic fields as a function of the nano-constriction width, w = 50 - 140 nm. The threshold current is found to scale linearly with w, defining a constant threshold current density of Jth = 1.7 x 10(8) A/cm(2). While the current dependence of the microwave frequency shows the same generic non-monotonic behavior for all w >= 80 nm, the quality of the generated microwave signal improves strongly with w, as the total power increases and the linewidth decreases linearly with w. As a consequence, the peak power for a 140 nm nano-constriction is about an order of magnitude higher than that for an 80 nm nano-constriction. The smallest nano-constriction, w = 50 nm, exhibits a different behavior with a higher power and a worse linewidth, indicating a crossover into a qualitatively different narrow-constriction regime.

  • 24.
    Azimi-Mousolou, Vahid
    et al.
    Univ Isfahan, Fac Math & Stat, Dept Appl Math & Comp Sci, Esfahan 8174673441, Iran.;Uppsala Univ, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden..
    Bergman, Anders
    Uppsala Univ, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden..
    Delin, Anna
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics. KTH, Centres, SeRC - Swedish e-Science Research Centre. Alballova Univ Ctr, Sch Engn Sci.
    Eriksson, Olle
    Uppsala Univ, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden.;Örebro Univ, Sch Sci & Technol, SE-70182 Örebro, Sweden..
    Pereiro, Manuel
    Uppsala Univ, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden..
    Thonig, Danny
    Uppsala Univ, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden.;Örebro Univ, Sch Sci & Technol, SE-70182 Örebro, Sweden..
    Sjoqvist, Erik
    Uppsala Univ, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden..
    Entanglement duality in spin-spin interactions2022In: Physical Review A: covering atomic, molecular, and optical physics and quantum information, ISSN 2469-9926, E-ISSN 2469-9934, Vol. 106, no 3, article id 032407Article in journal (Refereed)
    Abstract [en]

    We examine entanglement of thermal states for spin-1/2 dimers in external magnetic fields. Entanglement transition in the temperature-magnetic-field plane demonstrates a duality in spin-spin interactions. This identifies a pair of dual categories of symmetric and antisymmetric dimers with each category classified into toric entanglement classes. The entanglement transition line is preserved from each toric entanglement class to its dual toric class. The toric classification is an indication of the topological signature of the entanglement, which bring about topological stability that could be relevant for quantum information processing.

  • 25.
    Azimi-Mousolou, Vahid
    et al.
    Department of Applied Mathematics and Computer Science, Faculty of Mathematics and Statistics, University of Isfahan, Isfahan 81746-73441, Iran; Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden, Box 516.
    Bergman, Anders
    Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden, Box 516.
    Delin, Anna
    KTH, Centres, SeRC - Swedish e-Science Research Centre. KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Eriksson, Olle
    Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden, Box 516.
    Pereiro, Manuel
    Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden, Box 516.
    Thonig, Danny
    School of Science and Technology, Örebro University, SE-701 82 Örebro, Sweden.
    Sjöqvist, Erik
    Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden, Box 516.
    Transmon probe for quantum characteristics of magnons in antiferromagnets2023In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 108, no 9, article id 094430Article in journal (Refereed)
    Abstract [en]

    The detection of magnons and their quantum properties, especially in antiferromagnetic (AFM) materials, is a substantial step to realize many ambitious advances in the study of nanomagnetism and the development of energy efficient quantum technologies. The recent development of hybrid systems based on superconducting circuits provides the possibility to engineer quantum sensors that exploit different degrees of freedom. Here, we examine the magnon-photon-transmon hybridization based on bipartite AFM materials, which gives rise to an effective coupling between a transmon qubit and magnons in a bipartite AFM. We demonstrate how magnon modes, their chiralities, and quantum properties, such as nonlocality and two-mode magnon entanglement in bipartite AFMs, can be characterized through the Rabi frequency of the superconducting transmon qubit.

  • 26.
    Bahari, Helma Sadat
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics. Univ Tehran, Coll Sci, Sch Phys, North Kargar St, POB 14395-547, Tehran, Iran..
    Fei, Ye
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Toledo-Carrillo, Esteban Alejandro
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Leliopoulos, Christos
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Savaloni, Hadi
    Univ Tehran, Coll Sci, Sch Phys, North Kargar St,POB 14395-547, Tehran, Iran..
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Chitosan nanocomposite coatings with enhanced corrosion inhibition effects for copper2020In: International Journal of Biological Macromolecules, ISSN 0141-8130, E-ISSN 1879-0003, Vol. 162, p. 1566-1577Article in journal (Refereed)
    Abstract [en]

    A biopolymer coating on copper was prepared based on chitosan nanocomposite and its corrosion inhibition efficiency was investigated. Inclusion of silica nanoparticles substantially reduces swelling ratio of chitosan coating while enhancing its thermal stability. The corrosion resistance of chitosan-based coatings is improved by introducing 2-mercaptobenzothiazole and silica in the matrix. It is found that upon crosslinking the chitosan coatings, a higher corrosion resistance could be achieved and the highest inhibition efficiency for chitosan nanocomposite coatings is calculated as 85%. The corrosion mechanism is found closely related to mass transition and diffusion process, and also the polarization resistance contributes to the impedance. Calculated impedance using Kramers-Kronig transformation shows good agreement with experimental values, thus validating the impedance measurements. This study exhibits the enhanced efficiency of nanocomposite and potential of chitosan coatings in corrosion prevention for copper.

  • 27. Bainsla, L.
    et al.
    Kumar, A.
    Awad, A. A.
    Wang, Chunlei
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Zahedinejad, M.
    Behera, N.
    Fulara, H.
    Khymyn, R.
    Houshang, A.
    Weissenrieder, Jonas
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Åkerman, J.
    Ultrathin Ferrimagnetic GdFeCo Films with Low Damping2022In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 32, no 23, p. 2111693-, article id 2111693Article in journal (Refereed)
    Abstract [en]

    Ferromagnetic materials dominate as the magnetically active element in spintronic devices, but come with drawbacks such as large stray fields and low operational frequencies. Compensated ferrimagnets provide an alternative as they combine the ultrafast magnetization dynamics of antiferromagnets with a ferromagnet-like spin-orbit-torque behavior. However, to use ferrimagnets in spintronic devices their advantageous properties must be retained also in ultrathin films (t < 10 nm). In this study, ferrimagnetic Gdx(Fe87.5Co12.5)1−x thin films in the thickness range t = 2–20 nm are grown on high resistance Si(100) substrates and studied using broadband ferromagnetic resonance measurements at room temperature. By tuning their stoichiometry, a nearly compensated behavior is observed in 2 nm Gdx(Fe87.5Co12.5)1−x ultrathin films for the first time, with an effective magnetization of (Formula presented.) = 0.02 T and a low effective Gilbert damping constant of α = 0.0078, comparable to the lowest values reported so far in 30 nm films. These results show great promise for the development of ultrafast and energy efficient ferrimagnetic spintronic devices.

  • 28.
    Banuazizi, S. Amir Hossein
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics. Univ Tehran, Fac New Sci & Technol, Tehran, Iran..
    Houshang, Afshin
    Univ Gothenburg, Dept Phys, S-41296 Gothenburg, Sweden..
    Awad, Ahmad A.
    Univ Gothenburg, Dept Phys, S-41296 Gothenburg, Sweden..
    Mohammadi, Javad
    Univ Tehran, Fac New Sci & Technol, Tehran, Iran..
    Åkerman, Johan
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics. Univ Gothenburg, Dept Phys, S-41296 Gothenburg, Sweden..
    Belova, Lyubov
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Magnetic force microscopy of an operational spin nano-oscillator2022In: MICROSYSTEMS & NANOENGINEERING, ISSN 2055-7434, Vol. 8, no 1, article id 65Article in journal (Refereed)
    Abstract [en]

    Magnetic force microscopy (MFM) is a powerful technique for studying magnetic microstructures and nanostructures that relies on force detection by a cantilever with a magnetic tip. The detected magnetic tip interactions are used to reconstruct the magnetic structure of the sample surface. Here, we demonstrate a new method using MFM for probing the spatial profile of an operational nanoscale spintronic device, the spin Hall nano-oscillator (SHNO), which generates high-intensity spin wave auto-oscillations enabling novel microwave applications in magnonics and neuromorphic computing. We developed an MFM system by adding a microwave probe station to allow electrical and microwave characterization up to 40 GHz during the MFM process. SHNOs-based on NiFe/Pt bilayers with a specific design compatible with the developed system-were fabricated and scanned using a Co magnetic force microscopy tip with 10 nm spatial MFM resolution, while a DC current sufficient to induce auto-oscillation flowed. Our results show that this developed method provides a promising path for the characterization and nanoscale magnetic field imaging of operational nano-oscillators.

  • 29.
    Banuazizi, S. Amir Hossein
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Åkerman, Johan
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics. Univ Gothenburg, Dept Phys, S-41296 Gothenburg, Sweden..
    Microwave probe stations with throw-dimensional control of the magnetic field to study high-frequency dynamic in nanoscale devices2018In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 89, no 6, article id 064701Article in journal (Refereed)
    Abstract [en]

    We present two microwave probe stations with motorized rotary stages for adjusting the magnitude and angle of the applied magnetic field. In the first system, the magnetic field is provided by an electromagnet and can be adjusted from 0 to similar to 1.4 T while its polar angle (theta) can be varied from 0 degrees to 360 degrees. In the second system the magnetic field is provided by a Halbach array permanent magnet, which can be rotated and translated to cover the full range of polar (theta) and azimuthal (phi) angles with a tunable field magnitude up to similar to 1 T. Both systems are equipped with microwave probes, bias-Ts, amplifiers, and spectrum analyzers, to allow for microwave characterization up to 40 GHz, as well as software to automatically perform continuous large sets of electrical and microwave measurements.

  • 30.
    Banuazizi, Seyed Amir Hossein
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Determining and Optimizing the Current and Magnetic Field Dependence of Spin-Torque and Spin Hall Nano-Oscillators: Toward Next-Generation Nanoelectronic Devices and Systems2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Spin-torque and spin Hall nano-oscillators are nanoscale devices (about 100 nm) capable of producing tunable broadband high-frequency microwave signals ranging from 0.1 GHz to over 65 GHz that several research groups trying to reach up to 200 - 300 GHz. Their development is ongoing for applications in high-frequency nanoelectronic devices and systems, such as mobile phones, wireless networks, base stations, vehicle radars, and even medical applications.

    This thesis covers a wide range of characterizations of spin-torque and spin Hall nano-oscillator devices that aim to investigate their current and magnetic field dependency, as well as to suggest improvements in these devices to optimize their application in spintronics and magnonics. The work is primarily based on experimental methods for characterizing these devices by building up new measurement systems, but it also includes numerical and micromagnetic simulations.

    Experimental techniques: In order to characterize the fabricated nanodevices in a detailed and accurate manner through their electrical and microwave responses, new measurement systems capable of full 3D control over the external magnetic fields will be described. In addition, a new method of probing an operational device using magnetic force microscopy (MFM) will be presented.

    Spin-torque nano-oscillators: We will describe remarkable improvements in the performance of spin-torque nano-oscillators (STNOs) that enhance their integration capability with applications in microwave systems. In nanocontact (NC-)STNOs made from a conventional spin-valve stack, though with thicker bottom electrodes, it is found the auto-oscillations can be excited with higher frequencies at lower threshold currents, and with higher output powers. We also find that this idea is useful for tuning spin-wave resonance and also controlling the thermal budget. Furthermore, a detailed study of magnetic droplet solitons and spin-wave dynamics in NC-STNOs will be described. Finally, we demonstrate ultra-high frequency tunability in low-current STNOs based on perpendicular magnetic tunnel junctions(p-MTJs).

    Spin Hall nano-oscillators: Characterizations of spin Hall nano-oscillator(SHNO) devices based on different structures and materials with both conventional and novel methods will be described. A detailed study of the current, temperature, and magnetic field profiles of nanogap SHNOs will be presented. In addition, we show the current and magnetic field dependence of nanoconstriction-based SHNOs.Moreover, it is shown that multiple SHNOs can be serially synchronized, thereby increasing their output power and enhancing the usage of these devices in applications such as neuromorphic computing. We show synchronization of multiple nanoconstriction SHNOs in the presence of a low in-plane magnetic field. Finally, there is a demonstration of the results of a novel method for probing an operationalSHNO using MFM.

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  • 31.
    Banuazizi, Seyed Amir Hossein
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Houshang, Afshin
    A. Awad, Ahmad
    Belova, Lyubov M
    Åkerman, Johan
    Magnetic force microscopy of an operational nanodeviceManuscript (preprint) (Other academic)
    Abstract [en]

    We present a new method for probing the spatial profile of an operational magnetic nanodevice using magnetic force microscopy (MFM). We have developed an MFM system by adding a microwave probe station equipped with microwave probe, bias-T, and amplifier to allow electrical and microwave characterization up to 40 GHz during the MFM process. The nanoscale spintronic devices---spin Hall nano-oscillators (SHNOs) based on Pt/NiFe bilayers with a specific design compatible with the developed system---were fabricated and scanned using a Co magnetic force microscopy tip with 10 nm spatial resolution, while a DC current sufficient to exert auto-oscillation flowed. Our results show that this method of developed provides a promising path for the characterization of the spatial profiles of operational nano-oscillators.

  • 32.
    Banuazizi, Seyed Amir Hossein
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Mohseni, Seyed Majid
    R. Sani, Sohrab
    Eklund, Anders
    A. M. Naiini, Maziar
    Malm, B. Gunnar
    Åkerman, Johan
    Control of thermal budget in nanocontact spin-torque nano-oscillatorsManuscript (preprint) (Other academic)
    Abstract [en]

    We investigate the influence of the bottom Cu electrode thickness (tCu) in nanocontact spin-torque nano-oscillators (NC-STNOs) based on Si/SiO2/Pd(8)/Cu(tCu)/Co(8)/Cu(7)/NiFe(4.5)/Cu(3)/Pd(3) GMR stacks on the thermal budget of the magnetodynamically active region. Increasing tCu from 10 to 70 nm results in a ~50% reduction in Joule heating in both the Co and NiFe layers, which directly improves the microwave output stability and linewidth. Numerical simulations of the NC-STNO current distribution suggest that this improvement originates from a strongly reduced lateral current spread in the top ferromagnetic layer and a reduction in the device's resistance.

  • 33.
    Banuazizi, Seyed Amir Hossein
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Åkerman, Johan
    Microwave probe stations with three-dimensional control of the magnetic field to study high frequency dynamics in nanoscale devices2018In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623Article in journal (Refereed)
    Abstract [en]

    We present two microwave probe stations with motorized rotary stages for adjusting the magnitude and angle of the applied magnetic field. In the first system, the magnetic field is provided by an electromagnet and can be adjusted from 0 to ~ 1.4 T while its polar angle (θ) can be varied from 0o to 360o. In the second system the magnetic field is provided by a Halbach array permanent magnet, which can be rotated and translated to cover the full range of polar (θ) and azimuthal (φ) angles with a tunable field magnitude up to ~ 1 T. Both systems are equipped with microwave probes, bias-Ts, amplifiers, and spectrum analyzers, to allow for microwave characterization up to 40 GHz, as well as software to automatically perform continuous large sets of electrical and microwave measurements.

  • 34.
    Bassyouni, Fatma
    et al.
    Natl Res Ctr, Pharmaceut Ind Res Div, Chem Nat & Microbial Prod Dept, Cairo 12622, Egypt..
    Tarek, Mohammad
    Armed Forces Coll Med AFCM, Bioinformat Dept, Cairo 12622, Egypt..
    Salama, Abeer
    Natl Res Ctr, Div Med, Dept Pharmacol, Cairo 12622, Egypt..
    Ibrahim, Bassant
    Natl Res Ctr, Div Med, Dept Pharmacol, Cairo 12622, Egypt..
    Salah El Dine, Sawsan
    Natl Res Ctr, Div Med, Dept Pharmacol, Cairo 12622, Egypt..
    Yassin, Nemat
    Natl Res Ctr, Div Med, Dept Pharmacol, Cairo 12622, Egypt..
    Hassanein, Amina
    Natl Res Ctr, Div Med, Dept Pathol, Cairo 12622, Egypt..
    Moharam, Maysa
    Natl Res Ctr, Biotechnol Res Div, Chem Dept Microbial Prod, Cairo 12622, Egypt..
    Abdel-Rehim, Mohamed
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Promising Antidiabetic and Antimicrobial Agents Based on Fused Pyrimidine Derivatives: Molecular Modeling and Biological Evaluation with Histopathological Effect2021In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 26, no 8, article id 2370Article in journal (Refereed)
    Abstract [en]

    Diabetes is the most common metabolic disorder in both developing and non-developing countries, and a well-recognized global health problem. The WHO anticipates an increase in cases from 171 million in 2000 to 366 million by 2030. In the present study, we focus on the preparation of pyrimidine derivatives as potential antidiabetic and antimicrobial agents. Thein vivoeffect on total serum glucose concentration, cholesterol and antioxidant activity was assessed in adult male albino Wister rats and compared to the reference drug glimperide. Promising results were observed for compound 5. The histopathological study confirms that compound 5 results in significant activity with liver maintenance. The antimicrobial activities were evaluated against several bacterial strains such as Salmonella typhimurium ATCC 25566, Bacillus cereus, Escherichia coli NRRN 3008, Pseudomonas aeruginosa ATCC 10145, Staphylococcus aureus ATCC 6538and fungi such as Rhizopus oligosporus, Mucor miehei and Asperillus niger. Compounds 4 and 5 showed a good inhibition of the bacterial zone compared to the reference drug cephradine. Finally, we suggest protein targets for these drugs based on computational analysis, and infer their activities from their predicted modes of binding using molecular modeling. The molecular modeling for compounds 4 and 5 resulted in improved docking scores and hydrogen bonding. The docking studies are in good agreement with the in vitro and in vivo studies.

  • 35.
    Basumatary, I. B.
    et al.
    Department of Food Engineering and Technology, Central Institute of Technology Kokrajhar, Kokrajhar 783370, Assam, India.
    Mukherjee, A.
    Department of Food Engineering and Technology, Central Institute of Technology Kokrajhar, Kokrajhar 783370, Assam, India.
    Katiyar, V.
    Department of Chemical Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India.
    Kumar, S.
    Department of Food Engineering and Technology, Central Institute of Technology Kokrajhar, Kokrajhar 783370, Assam, India.
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Chitosan-based antimicrobial coating for improving postharvest shelf life of pineapple2021In: Coatings, ISSN 2079-6412, Vol. 11, no 11, article id 1366Article in journal (Refereed)
    Abstract [en]

    Rapid postharvest losses and quality deteriorations in pineapple are major challenges to growers and handlers. Chitosan-based coatings on fruit surfaces have gained importance in recent years to enhance postharvest shelf life of the fruits. In this study, aloe vera gel was added as a natural antioxidant in chitosan-based composite coating containing ZnO nanoparticles. The developed formulation was applied on the surface of freshly harvested pineapple fruits. ZnO nanoparticles were used as an antimicrobial agent. Coated pineapple fruits were evaluated for weight loss, total soluble solids, titratable acidity, decay index, maturity index, and sensory attributes, including visual appearance, periodically at 5 day interval during storage. The results showed that the coating of the fruit reduced weight loss by about 5%, and also delayed ripening and oxidative decay compared to the uncoated fruit. Thus, the developed coating formulation is a promising sustainable solution to reduce postharvest losses and to extend shelf life of pineapples.

  • 36.
    Basumatary, Indra Bhusan
    et al.
    Cent Inst Technol Kokrajhar, Dept Food Engn & Technol, Kokrajhar 783370, Assam, India..
    Mukherjee, Avik
    Cent Inst Technol Kokrajhar, Dept Food Engn & Technol, Kokrajhar 783370, Assam, India..
    Katiyar, Vimal
    Indian Inst Technol Guwahati, Dept Chem Engn, Gauhati 781039, Assam, India..
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Kumar, Santosh
    Cent Inst Technol Kokrajhar, Dept Food Engn & Technol, Kokrajhar 783370, Assam, India..
    Chitosan-based active coating for pineapple preservation: Evaluation of antimicrobial efficacy and shelf-life extension2022In: Lebensmittel-Wissenschaft + Technologie, ISSN 0023-6438, E-ISSN 1096-1127, Vol. 168, p. 113940-, article id 113940Article in journal (Refereed)
    Abstract [en]

    Pineapple is a tropical fruit that is the most economically significant member of the Bromeliaceae family that are rich in flavonoids, phenolic acids, and antioxidants, which protect human cells from free radicals known to cause chronic diseases. However, short postharvest shelf-life of the fruit limits its long-distance distribution and consumption. Chitosan is a positively charged polysaccharide consisting of N-acetyl D-glucosamine and D-glucosamine units that can be used as a promising sustainable biopolymer for active coating of the fruit. In this work, chitosan-based nanocomposite formulations were prepared with added eugenol (clove essential oil) and Aloe vera gel as antioxidant, antibacterial and antifungal agents. The results showed that the incorporation of eugenol oil nanoemulsion and Aloe vera gel in the coatings enhanced their physico-chemical and functional properties including antimicrobial activities against four foodborne bacterial pathogens (Escherichia coli, Alcaligenes faecalis, Staphylococcus aureus, and Bacillus subtilis) and two fungal isolates. The developed coatings not only kept the pineapple fresh, but also preserved its quality and prolonged their shelf-life by up to three weeks during storage in ambient conditions.

  • 37. Bathen, M. E.
    et al.
    Linnarsson, Margareta K.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Ghezellou, M.
    Hassan, J. U.
    Vines, L.
    Influence of carbon cap on self-diffusion in silicon carbide2020In: Crystals, ISSN 2073-4352, Vol. 10, no 9, p. 1-11, article id 752Article in journal (Refereed)
    Abstract [en]

    Self-diffusion of carbon (12C and13C) and silicon (28Si and30Si) in 4H silicon carbide has been investigated by utilizing a structure containing an isotope purified 4H-28Si12C epitaxial layer grown on an n-type (0001) 4H-SiC substrate, and finally covered by a carbon capping layer (C-cap). The13C and30Si isotope profiles were monitored using secondary ion mass spectrometry (SIMS) following successive heat treatments performed at 2300–2450◦C in Ar atmosphere using an inductively heated furnace. The30Si profiles show little redistribution within the studied temperature range, with the extracted diffusion lengths for Si being within the error bar for surface roughening during annealing, as determined by profilometer measurements. On the other hand, a significant diffusion of13C was observed into the isotope purified layer from both the substrate and the C-cap. A diffusivity of D = 8.3 × 106 e−10.4/kBT cm2/s for13C was extracted, in contrast to previous findings that yielded lower both pre-factors and activation energies for C self-diffusion in SiC. The discrepancy between the present measurements and previous theoretical and experimental works is ascribed to the presence of the C-cap, which is responsible for continuous injection of C interstitials during annealing, and thereby suppressing the vacancy mediated diffusion.

  • 38.
    Batili, Hazal
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Hamawandi, Bejan
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Ergül, Adem Björn
    KTH, School of Engineering Sciences (SCI), Applied Physics, Nanostructure Physics.
    Toprak, Muhammet
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. KTH, School of Biotechnology (BIO), Centres, Albanova VinnExcellence Center for Protein Technology, ProNova. KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics. KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    On the electrophoretic deposition of Bi2Te3 nanoparticles through electrolyte optimization and substrate design2022In: Colloids and Surfaces A: Physicochemical and Engineering Aspects, ISSN 0927-7757, E-ISSN 1873-4359, Vol. 649, p. 129537-, article id 129537Article in journal (Refereed)
    Abstract [en]

    Assembly of thermoelectric nanostructures with pre-defined morphology and surface chemistry on solid sub-strates has been one of the challenges for in-plane TE devices. Electrophoretic deposition (EPD) has the potential to be used for this purpose, where the use of non-conductive substrates is required to enable a reliable evaluation of the transport property of electrically active films. Bi2Te3 nanoparticles, which were synthesized using microwave-assisted hydrothermal route, were used for the EPD of thermoelectric films on glass substrates. A special substrate was fabricated using maskless photolithography, to evaluate the electronic transport properties of the TE films without the interference of the substrate. Electrolyte composition was optimized for high mobility of the suspended nanoparticles, and Bi2Te3 EPD films were fabricated with a high deposition rate, reaching 10 mu m/min. Initial EPD films showed high resistivity, ascribed to the surface oxide layer and capping ligands. The resistance was significantly reduced by the addition of a dithiol molecular linker, capable of interconnecting the Bi2Te3 nanoparticles through ligand-exchange. Seebeck coefficient in the range-150 to-180 mu V/K was measured, revealing the transport through the deposited films. Finally, a power factor of 169 nW/K-2.m was estimated, revealing the potential for the application of this technology to large area TE films as active coatings using the developed EPD process.

  • 39.
    Batvandi, Mohammadreza
    et al.
    Islamic Azad Univ, Dept Phys, Ahvaz Branch, Ahvaz, Iran..
    Haghighatzadeh, Azadeh
    Islamic Azad Univ, Adv Surface Engn & Nano Mat Res Ctr, Dept Phys, Ahvaz Branch, Ahvaz, Iran..
    Mazinani, Babak
    Malayer Univ, Dept Mat Engn, Malayer, Iran..
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Visible-light-driven photocatalysis with Z-scheme Ag3PO4@N-GQDs@g-C3N4 nano/hetero-junctions2022In: Applied Physics A: Materials Science & Processing, ISSN 0947-8396, E-ISSN 1432-0630, Vol. 128, no 10, article id 853Article in journal (Refereed)
    Abstract [en]

    The fabrication and improved performance of Z-scheme visible-light-driven Ag3PO4@N-GQDs@g-C3N4 ternary nano/hetero-junctions have been described in this study. Fern-like silver orthophosphate (Ag3PO4) microstructures have been modified using nitrogen-doped graphene quantum dots (N-GQDs) and then have been coated by ultrathin graphitic carbon nitride (g-C3N4) sheets via a combined technique including freeze-drying and refluxing methods. Photocatalytic studies have been conducted through visible-light photo-degradation of standard methylene blue dye in aqueous media. The Ag3PO4@N-GQDs@g-C3N4 ternary nano/hetero-junctions have exhibited the promoted photocatalytic efficiency of 97.91%, which is about 1.07 and 1.34 times higher than that of Ag3PO4@g-C3N4 binary nano/hetero-junctions (91.46%) and pristine-Ag3PO4 microstructures (85.91%), respectively. The excellent recyclability of the Ag3PO4@N-GQDs@g-C3N4 photo-catalyst has been verified in the cycle operations in which the recycling efficiency could have been maintained at 94.92% after five runs of experiments. The quenching effects of scavengers have suggested that the superoxide radicals (O-2(-center dot)) and holes (h(+)) are the predominant active species governing the photocatalytic reaction of the Ag3PO4@N-GQDs@g-C3N4 ternary composite due to a Z-scheme junction. The improved photocatalytic activity of Ag3PO4@N-GQDs@g-C3N4 nano/hetero-junctions could have been ascribed to the higher visible-light harvesting capacity, better charge carrier separation and stronger oxidation and reduction ability relevant to the indirect Z-scheme system where N-GQDs act as an efficient electron transfer media.

  • 40.
    Beaulieu, Samuel
    et al.
    Max Planck Gesell, Fritz Haber Inst, Faradayweg 4-6, D-14195 Berlin, Germany.;Univ Bordeaux, CNRS, UMR5107, CELIA,CEA, F-33405 Talence, France..
    Dong, Shuo
    Max Planck Gesell, Fritz Haber Inst, Faradayweg 4-6, D-14195 Berlin, Germany..
    Tancogne-Dejean, Nicolas
    Max Planck Inst Struct & Dynam Matter, Luruper Chaussee 149, D-22761 Hamburg, Germany..
    Dendzik, Maciej
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics. Max Planck Gesell, Fritz Haber Inst, Faradayweg 4-6, D-14195 Berlin, Germany..
    Pincelli, Tommaso
    Max Planck Gesell, Fritz Haber Inst, Faradayweg 4-6, D-14195 Berlin, Germany..
    Maklar, Julian
    Max Planck Gesell, Fritz Haber Inst, Faradayweg 4-6, D-14195 Berlin, Germany..
    Xian, R. Patrick
    Max Planck Gesell, Fritz Haber Inst, Faradayweg 4-6, D-14195 Berlin, Germany..
    Sentef, Michael A.
    Max Planck Inst Struct & Dynam Matter, Luruper Chaussee 149, D-22761 Hamburg, Germany..
    Wolf, Martin
    Max Planck Gesell, Fritz Haber Inst, Faradayweg 4-6, D-14195 Berlin, Germany..
    Rubio, Angel
    Max Planck Inst Struct & Dynam Matter, Luruper Chaussee 149, D-22761 Hamburg, Germany.;Flatiron Inst, Ctr Computat Quantum Phys CCQ, 162 Fifth Ave, New York, NY 10010 USA..
    Rettig, Laurenz
    Max Planck Gesell, Fritz Haber Inst, Faradayweg 4-6, D-14195 Berlin, Germany..
    Ernstorfer, Ralph
    Max Planck Gesell, Fritz Haber Inst, Faradayweg 4-6, D-14195 Berlin, Germany..
    Ultrafast dynamical Lifshitz transition2021In: Science Advances, E-ISSN 2375-2548, Vol. 7, no 17, article id eabd9275Article in journal (Refereed)
    Abstract [en]

    Fermi surface is at the heart of our understanding of metals and strongly correlated many-body systems. An abrupt change in the Fermi surface topology, also called Lifshitz transition, can lead to the emergence of fascinating phenomena like colossal magnetoresistance and superconductivity. While Lifshitz transitions have been demonstrated for a broad range of materials by equilibrium tuning of macroscopic parameters such as strain, doping, pressure, and temperature, a nonequilibrium dynamical route toward ultrafast modification of the Fermi surface topology has not been experimentally demonstrated. Combining time-resolved multidimensional photoemission spectroscopy with state-of-the-art TDDFT+U simulations, we introduce a scheme for driving an ultrafast Lifshitz transition in the correlated type-II Weyl semimetal T-d-MoTe2. We demonstrate that this nonequilibrium topological electronic transition finds its microscopic origin in the dynamical modification of the effective electronic correlations. These results shed light on a previously unexplored ultrafast scheme for controlling the Fermi surface topology in correlated quantum materials.Y

  • 41.
    Benedek, Peter
    et al.
    Swiss Fed Inst Technol, Dept Informat Technol & Elect Engn, CH-8092 Zurich, Switzerland..
    Forslund, Ola Kenji
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Nocerino, Elisabetta
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Yazdani, Nuri
    Swiss Fed Inst Technol, Dept Informat Technol & Elect Engn, CH-8092 Zurich, Switzerland..
    Matsubara, Nami
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Sassa, Yasmine
    Chalmers Univ Technol, Dept Phys, SE-41296 Gothenburg, Sweden..
    Juranyi, Fanni
    Paul Scherrer Inst, Lab Neutron Scattering & Imaging, CH-5232 Villigen, Switzerland..
    Medarde, Marisa
    Paul Scherrer Inst, Lab Multiscale Mat Experiments, CH-5232 Villigen, Switzerland..
    Telling, Mark
    Rutherford Appleton Lab, ISIS Neutron & Muon Facil, Didcot OX11 0QX, Oxon, England..
    Månsson, Martin
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Wood, Vanessa
    Swiss Fed Inst Technol, Dept Informat Technol & Elect Engn, CH-8092 Zurich, Switzerland..
    Quantifying Diffusion through Interfaces of Lithium-Ion Battery Active Materials2020In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 12, no 14, p. 16243-16249Article in journal (Refereed)
    Abstract [en]

    Detailed understanding of charge diffusion processes in a lithium-ion battery is crucial to enable its systematic improvement. Experimental investigation of diffusion at the interface between active particles and the electrolyte is challenging but warrants investigation as it can introduce resistances that, for example, limit the charge and discharge rates. Here, we show an approach to study diffusion at interfaces using muon spin spectroscopy. By performing measurements on LiFePO4 platelets with different sizes, we determine how diffusion through the LiFePO4 (010) interface differs from that in the center of the particle (i.e., bulk diffusion). We perform ab initio calculations to aid the understanding of the results and show the relevance of our interfacial diffusion measurement to electrochemical performance through cyclic voltammetry measurements. These results indicate that surface engineering can be used to improve the performance of lithium-ion batteries.

  • 42.
    Benedek, Peter
    et al.
    Swiss Fed Inst Technol, Dept Informat Technol & Elect Engn, CH-8092 Zurich, Switzerland..
    Yazdani, Nuri
    Swiss Fed Inst Technol, Dept Informat Technol & Elect Engn, CH-8092 Zurich, Switzerland..
    Chen, Hungru
    Univ Bath, Dept Chem, Bath BA2 7AY, Avon, England..
    Wenzler, Nils
    Swiss Fed Inst Technol, Dept Informat Technol & Elect Engn, CH-8092 Zurich, Switzerland..
    Juranyi, Fanni
    Paul Scherrer Inst, Lab Neutron Scattering & Imaging, CH-5232 Villigen, Switzerland..
    Månsson, Martin
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Islam, M. Saiful
    Univ Bath, Dept Chem, Bath BA2 7AY, Avon, England..
    Wood, Vanessa C.
    Swiss Fed Inst Technol, Dept Informat Technol & Elect Engn, CH-8092 Zurich, Switzerland..
    Surface phonons of lithium ion battery active materials2019In: Sustainable Energy & Fuels, E-ISSN 2398-4902, Vol. 3, no 2, p. 508-513Article in journal (Refereed)
    Abstract [en]

    Surfaces of active materials are understood to play an important role in the performance and lifetime of lithium-ion batteries, but they remain poorly characterized and therefore cannot yet be systematically designed. Here, we combine inelastic neutron scattering and ab initio simulations to demonstrate that the structure of the surface of active materials differs from the interior of the particle. We use LiFePO4 (LFP) as a model system, and we find that carbon coating influences the Li-O bonding on the (010) LFP surface relative to the bulk. Our results highlight how coatings can be used to systematically engineer the vibrations of atoms at the surface of battery active materials, and thereby impact lithium ion transport, charge transfer, and surface reactivity.

  • 43.
    Berglund, Lars
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Li, Yuanyuan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Fu, Qiliang
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Popov, Sergei
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Sychugov, Ilya
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Yang, Min
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Modification of transparent wood for photonics functions2018In: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 255Article in journal (Other academic)
  • 44.
    Biswas, Rabindra
    et al.
    Indian Inst Sci, Dept Elect Commun Engn, Bangalore 560012, Karnataka, India..
    Vennberg, Felix
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Ravishankar, Ajith Padyana
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Anand, Srinivasan
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Raghunathan, Varun
    Indian Inst Sci, Dept Elect Commun Engn, Bangalore 560012, Karnataka, India..
    Enhanced Sum Frequency Generation using Vertically Stacked Mie Resonators2024In: ULTRAFAST PHENOMENA AND NANOPHOTONICS XXVIII / [ed] Betz, M Elezzabi, AY, SPIE-Intl Soc Optical Eng , 2024, Vol. 12884, article id 128840DConference paper (Refereed)
    Abstract [en]

    III-V semiconductors, such as Aluminium Gallium Arsenide (AlGaAs), are known for their high refractive index and strong non-resonant second-order optical nonlinearity making them useful for building active nonlinear photonic devices. AlGaAs-based nanophotonic structures supporting anapole resonances can significantly boost the internal electric fields resulting in enhanced nonlinear optical response. However, low-quality factors of these anapolar resonances can result in poor conversion efficiency for the nonlinear optical process. Here we report enhanced sum frequency generation (SFG) from vertically stacked three-disk AlGaAs-based nanoresonators supporting anapole type resonance that exhibit an order of magnitude increase in field enhancement compared to a single-disk resonator system at the SFG wavelength. The vertically stacked resonators consist of three individual AlGaAs layers separated vertically by an under-cut Gallium Arsenide (GaAs) stem. Finite difference time domain (FDTD) simulations of the scattering cross sections were performed to optimize the dimensions of AlGaAs resonator. The optimal structure consists of three vertically stacked AlGaAs nanodisks (550 nm diameter, 50 nm height) separated by a 100 nm GaAs stem. This design ensures anapole type resonance overlap at SFG wavelength (600-670 nm). Multi-spectral SFG images were acquired by varying the input signal wavelength in the range of 1400-1800 nm, keeping the pump wavelength fixed at 1040 nm. The experimental results show a maximum SFG enhancement of approximately 50-times near the resonance wavelength of 645 nm in comparison to unpatterned multilayer samples. Optical nanostructures based on stacked AlGaAs resonators provide a very exciting platform to tailor the light-matter interactions for linear and non-linear optical applications.

  • 45.
    Bleiker, Simon J.
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Dubois, Valentin J.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Gylfason, Kristinn
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Niklaus, Frank
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Ottonello Briano, Floria
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Quellmalz, Arne
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics. KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Device with a waveguide supported on a substrate and method for its fabrication2020Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    ABSTRACT A device (1) and a method for fabricating such a device is described. The device (1) comprises a device layer (4), a substrate (2) defining a substrate plane (3). A device layer plane (5) is defined on the side of the device layer (4) facing the substrate (2). The device also comprises a waveguide (7) for guiding an electromagnetic wave. The waveguide (7) is supported on the substrate (2) via a support structure (6) extending from the substrate (2) to the device layer (4). The ratio of the largest distance (D1), perpendicular to the substrate plane (3), between a free surface of the waveguide (7) facing the substrate and any solid material to the height (h) of the waveguide (7) is more than 6, i.e. D1/h \textgreater 6. The ratio of the distance (D2), perpendicular to the substrate plane (3), between the device layer plane (5) and the substrate plane (3) to the height (h) of the waveguide (7) is more than 6, i.e. D2/h \textgreater 6.

  • 46.
    Borisov, Vladislav
    et al.
    Uppsala Univ, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden..
    Kvashnin, Yaroslav O.
    Uppsala Univ, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden..
    Ntallis, Nikolaos
    Uppsala Univ, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden..
    Thonig, Danny
    Örebro Univ, Sch Sci & Technol, SE-70182 Örebro, Sweden..
    Thunström, Patrik
    Uppsala Univ, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden..
    Pereiro, Manuel
    Uppsala Univ, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden..
    Bergman, Anders
    Uppsala Univ, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden..
    Sjöqvist, Erik
    Uppsala Univ, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden..
    Delin, Anna
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics. KTH, Centres, SeRC - Swedish e-Science Research Centre.
    Nordström, Lars
    Uppsala Univ, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden..
    Eriksson, Olle
    Uppsala Univ, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden.;Örebro Univ, Sch Sci & Technol, SE-70182 Örebro, Sweden..
    Heisenberg and anisotropic exchange interactions in magnetic materials with correlated electronic structure and significant spin-orbit coupling2021In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 103, no 17, article id 174422Article in journal (Refereed)
    Abstract [en]

    The Dzyaloshinskii-Moriya (DM) interaction, as well as symmetric anisotropic exchange, are important ingredients for stabilizing topologically nontrivial magnetic textures, such as, e.g., skyrmions, merons, and hopfions. These types of textures are currently in focus from a fundamental science perspective and they are also discussed in the context of future spintronics information technology. While the theoretical understanding of the Heisenberg exchange interactions is well developed, it is still a challenge to access, from first principles theory, the DM interaction as well as the symmetric anisotropic exchange, which both require a fully-relativistic treatment of the electronic structure, in magnetic systems where substantial electron-electron correlations are present. Here, we present results of a theoretical framework which allows to compute these interactions in any given system and demonstrate its performance for several selected cases, for both bulk and low-dimensional systems. We address several representative cases, including the bulk systems CoPt and FePt, the B20 compounds MnSi and FeGe as well as the low-dimensional transition metal bilayers Co/Pt(111) andMn/W(001). The effect of electron-electron correlations is analyzed using dynamical mean-field theory on the level of the spin-polarized T -matrix + fluctuating exchange (SPTF) approximation, as regards the strength and character of the isotropic (Heisenberg) and anisotropic (DM) interactions in relation to the underlying electronic structure. Our method can be combined with more advanced techniques for treating correlations, e.g., quantum Monte Carlo and exact diagonalization methods for the impurity solver of dynamical mean-field theory. We find that correlation-induced changes of the DM interaction can be rather significant, with up to fivefold modifications in the most distinctive case.

  • 47.
    Borisov, Vladislav
    et al.
    Department of Physics and Astronomy, Uppsala University, Box 516, SE-75120, Uppsala, Sweden, Box 516.
    Salehi, Nastaran
    Department of Physics and Astronomy, Uppsala University, Box 516, SE-75120, Uppsala, Sweden, Box 516.
    Pereiro, Manuel
    Department of Physics and Astronomy, Uppsala University, Box 516, SE-75120, Uppsala, Sweden, Box 516.
    Delin, Anna
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Eriksson, Olle
    Department of Physics and Astronomy, Uppsala University, Box 516, SE-75120, Uppsala, Sweden, Box 516; Wallenberg Initiative Materials Science for Sustainability, Uppsala University, 75121, Uppsala, Sweden.
    Dzyaloshinskii-Moriya interactions, Néel skyrmions and V4 magnetic clusters in multiferroic lacunar spinel GaV4S82024In: npj Computational Materials, E-ISSN 2057-3960, Vol. 10, no 1, article id 53Article in journal (Refereed)
    Abstract [en]

    Using ab initio density functional theory with static mean-field correlations, we calculate the Heisenberg and Dzyaloshinskii-Moriya interactions (DMI) for an atomistic spin Hamiltonian for the lacunar spinel, GaV4S8. The parameters describing these interactions are used in atomistic spin dynamics and micromagnetic simulations. The magnetic properties of the lacunar spinel GaV4S8, a material well-known from experiment to host magnetic skyrmions of Néel character, are simulated with these ab initio calculated parameters. The Dzyaloshinskii-Moriya contribution to the micromagnetic energy is a sum of two Lifshitz invariants, supporting the formation of Néel skyrmions and its symmetry agrees with what is usually expected for C3ν-symmetric systems. There are several conclusions one may draw from this work. One concerns the quantum nature of the magnetism, where we show that the precise magnetic state of the V4 cluster is crucial for understanding quantitatively the magnetic phase diagram. In particular, we demonstrate that a distributed-moment state of each V4 cluster explains well a variety of properties of GaV4S8, such as the band gap, observed Curie temperature and especially the stability of Néel skyrmions in the experimentally relevant temperature and magnetic-field range. In addition, we find that electronic correlations change visibly the calculated value of the DMI.

  • 48.
    Borlenghi, Simone
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Boman, Magnus
    KTH, School of Electrical Engineering and Computer Science (EECS), Computer Science, Software and Computer systems, SCS. RISE SICS, Electrum 229, SE-16429 Kista, Sweden..
    Delin, Anna
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics. KTH, Centres, SeRC - Swedish e-Science Research Centre.
    Modeling reservoir computing with the discrete nonlinear Schrodinger equation2018In: Physical review. E, ISSN 2470-0045, E-ISSN 2470-0053, Vol. 98, no 5, article id 052101Article in journal (Refereed)
    Abstract [en]

    We formulate, using the discrete nonlinear Schrodinger equation (DNLS), a general approach to encode and process information based on reservoir computing. Reservoir computing is a promising avenue for realizing neuromorphic computing devices. In such computing systems, training is performed only at the output level by adjusting the output from the reservoir with respect to a target signal. In our formulation, the reservoir can be an arbitrary physical system, driven out of thermal equilibrium by an external driving. The DNLS is a general oscillator model with broad application in physics, and we argue that our approach is completely general and does not depend on the physical realization of the reservoir. The driving, which encodes the object to be recognized, acts as a thermodynamic force, one for each node in the reservoir. Currents associated with these thermodynamic forces in turn encode the output signal from the reservoir. As an example, we consider numerically the problem of supervised learning for pattern recognition, using as a reservoir a network of nonlinear oscillators.

  • 49.
    Borlenghi, Simone
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Delin, Anna
    KTH, Centres, SeRC - Swedish e-Science Research Centre. KTH, School of Engineering Sciences (SCI), Applied Physics.
    Stochastic Thermodynamics of Oscillators' Networks2018In: Entropy, E-ISSN 1099-4300, Vol. 20, no 12, article id 992Article in journal (Refereed)
    Abstract [en]

    We apply the stochastic thermodynamics formalism to describe the dynamics of systems of complex Langevin and Fokker-Planck equations. We provide in particular a simple and general recipe to calculate thermodynamical currents, dissipated and propagating heat for networks of nonlinear oscillators. By using the Hodge decomposition of thermodynamical forces and fluxes, we derive a formula for entropy production that generalises the notion of non-potential forces and makes transparent the breaking of detailed balance and of time reversal symmetry for states arbitrarily far from equilibrium. Our formalism is then applied to describe the off-equilibrium thermodynamics of a few examples, notably a continuum ferromagnet, a network of classical spin-oscillators and the Frenkel-Kontorova model of nano friction.

  • 50.
    Boucly, Anthony
    et al.
    Sorbonne Univ, CNRS UMR 7614, Lab Chim Phys Matiere & Rayonnement, 4 Pl Jussieu, F-75252 Paris 05, France..
    Rochet, Francois
    Sorbonne Univ, CNRS UMR 7614, Lab Chim Phys Matiere & Rayonnement, 4 Pl Jussieu, F-75252 Paris 05, France.;Synchrotron SOLEIL, BP 48, F-91192 Gif Sur Yvette, France..
    Arnoux, Quentin
    Sorbonne Univ, CNRS UMR 7614, Lab Chim Phys Matiere & Rayonnement, 4 Pl Jussieu, F-75252 Paris 05, France..
    Gallet, Jean-Jacques
    Sorbonne Univ, CNRS UMR 7614, Lab Chim Phys Matiere & Rayonnement, 4 Pl Jussieu, F-75252 Paris 05, France.;Synchrotron SOLEIL, BP 48, F-91192 Gif Sur Yvette, France..
    Bournel, Fabrice
    Sorbonne Univ, CNRS UMR 7614, Lab Chim Phys Matiere & Rayonnement, 4 Pl Jussieu, F-75252 Paris 05, France.;Synchrotron SOLEIL, BP 48, F-91192 Gif Sur Yvette, France..
    Tissot, Heloise
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics. Sorbonne Univ, CNRS UMR 7614, Lab Chim Phys Matiere & Rayonnement, 4 Pl Jussieu, F-75252 Paris 05, France.;Synchrotron SOLEIL, BP 48, F-91192 Gif Sur Yvette, France.
    Marry, Virginie
    Sorbonne Univ, CNRS UMR 8234, Physicochim Electrolyses & Nanosyst Interfaciaux, 4 Pl Jussieu, F-75252 Paris 05, France..
    Dubois, Emmanuelle
    Sorbonne Univ, CNRS UMR 8234, Physicochim Electrolyses & Nanosyst Interfaciaux, 4 Pl Jussieu, F-75252 Paris 05, France..
    Michot, Laurent
    Sorbonne Univ, CNRS UMR 8234, Physicochim Electrolyses & Nanosyst Interfaciaux, 4 Pl Jussieu, F-75252 Paris 05, France..
    Soft X-ray Heterogeneous Radiolysis of Pyridine in the Presence of Hydrated Strontium-Hydroxyhectorite and its Monitoring by Near-Ambient Pressure Photoelectron Spectroscopy2018In: Scientific Reports, E-ISSN 2045-2322, Vol. 8, article id 6164Article in journal (Refereed)
    Abstract [en]

    The heterogeneous radiolysis of organic molecules in clays is a matter of considerable interest in astrochemistry and environmental sciences. However, little is known about the effects of highly ionizing soft X-rays. By combining monochromatized synchrotron source irradiation with in situ Near Ambient Pressure X-ray Photoelectron Spectroscopy (in the mbar range), and using the synoptic view encompassing both the gas and condensed phases, we found the water and pyridine pressure conditions under which pyridine is decomposed in the presence of synthetic Sr2+-hydroxyhectorite. The formation of a pyridine/water/Sr2+ complex, detected from the Sr 3d and N 1s core-level binding energies, likely presents a favorable situation for the radiolytic breaking of the O-H bond of water molecules adsorbed in the clay and the subsequent decomposition of the molecule. However, decomposition stops when the pyridine pressure exceeds a critical value. This observation can be related to a change in the nature of the active radical species with the pyridine loading. This highlights the fact that the destruction of the molecule is not entirely determined by the properties of the host material, but also by the inserted organic species. The physical and chemical causes of the present observations are discussed.

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