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  • 122501.
    Zhou, Yang
    et al.
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Nordmark, Arne
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strukturmekanik.
    Eriksson, Anders
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strukturmekanik.
    Multi-parametric stability investigation for thin spherical membranes with contacts2017Ingår i: International Journal of Mechanical Sciences, ISSN 0020-7403, E-ISSN 1879-2162, Vol. 131-132, s. 334-344Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The instability behavior for a thin truncated spherical membrane completely filled with fluid or containing both gas and fluid, fixed on a circular platform and in contact with two vertical planes was investigated. Different penalty functions for contacts, and symmetry aspects of the discretized model were studied, and gave effects on instability behavior. Stability conclusions for the multi-parametric problems were made using generalized eigenvalue analyses, showing limit points, bifurcation points and turning point. Contact conditions were shown to introduce bifurcations and secondary paths, dependent on the contact implementations and discretizations. Their effects on stability behaviors in connection with various controlling equations are discussed.

  • 122502. Zhou, Ye
    et al.
    Liedberg, Bo
    Gorochovceva, Natalij
    Makuska, Ricardas
    Dedinaite, Andra
    KTH, Skolan för kemivetenskap (CHE), Kemi, Ytkemi.
    Claesson, Per Martin
    KTH, Skolan för kemivetenskap (CHE), Kemi, Ytkemi.
    Chitosan-N-poly (ethylene oxide) brush polymers for reduced nonspecific protein adsorption2007Ingår i: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 305, nr 1, s. 62-71Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The possibility of using a novel comb polymer consisting of a chitosan backbone with grafted 44 units long poly(ethylene oxide) side chains for reducing nonspecific protein adsorption to gold surfaces functionalized by COOH-terminated thiols has been explored. The comb polymer was attached to the surface in three different ways: by solution adsorption, covalent coupling, and microcontact printing. The protein repellant properties were tested by monitoring the adsorption of bovine serum albumin and fibrinogen employing surface plasmon resonance and imaging null ellipsometry. It was found that a significant reduction in protein adsorption is achieved as the comb polymer layer is sufficiently dense. For solution adsorption this was achieved by adsorption from high pH solutions. On the other hand, the best performance of the microcontact printed surfaces was obtained when the stamp was inked either at low or at high pH. For a given comb polymer layer thickness/poly(ethylene oxide) density, significant differences in protein repellant properties were observed between the different preparation methods, and it is suggested that a reduction in the mobility of the comb polymer layer generated by covalent attachment favors a reduced protein adsorption. (c) 2006 Elsevier Inc. All rights reserved.

  • 122503. Zhou, Ye
    et al.
    Tian, Yuan
    Wang, Keyou
    Ghandhari, Mehrdad
    KTH, Skolan för elektro- och systemteknik (EES), Elkraftteknik.
    ROBUST OPTIMIZATION FOR AC-DC POWER FLOW BASED ON SECOND-ORDER CONE PROGRAMMING2017Ingår i: The Journal of Engineering, ISSN 1872-3284, E-ISSN 2051-3305Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents an adjustable robust optimization method for AC-DC optimal power flow (OPF) considering the uncertainty of renewable energy source (RESs). The optimal power flow of AC-DC system is modeled as a second-order cone (SOC) problem, and the affinely adjustable robust OPF (AAROPF) formulation is proposed. To apply AAROPF, the base-point generation is calculated and determined to match the power with forecasted RES output before the realization of the uncertainty. And once the uncertainty is revealed, generators reschedule its output through participation factors responding to the uncertain fluctuation of RES output to ensure a feasible solution for all realizations of RES output within a prescribed uncertainty set. Numerical results are obtained on a modified AC-DC IEEE 30-bus to minimize the expected operational cost. Results reveal a higher cost using AAROPF than the deterministic case, but it obtains a more robust solution with higher successful rates.

  • 122504. Zhou, Yi
    et al.
    Zhao, Xiaogang
    Zhao, Jianyu
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE).
    Chen, Du
    Research on Fire and Explosion Accidents of Oil Depots2016Ingår i: 3rd International Conference on Applied Engineering, AIDIC - associazione italiana di ingegneria chimica, 2016, Vol. 51, s. 163-168Konferensbidrag (Refereegranskat)
    Abstract [en]

    Fire and explosion accidents occurred frequently in oil depots in China which lead to great casualties, severe environmental pollution and large economic losses. Case studies of 435 fire and explosion accidents of oil depots in China from 1951 to 2013 are reviewed in this paper. From the analysis of time scale, area, facilities & equipment, ignition sources, types of accident substances, and responsibility, the statistic results show that the most dangerous area is the loading and unloading operation area, and the most vulnerable facilities & equipment are the storage tanks. Meanwhile, the proportions of ignition sources are so evenly distributed that the prevention of fire and explosion should be equally concentrated to several impact factors. The vapor cloud explosion could be the most common accident type in oil depots, and the management responsibility dominates in all of the accident causes. According to data analysis, special lessons learned from these accidents are proposed, and the majority of fire and explosion accidents in oil depots would have been prevented or avoided if security management had been improved.

  • 122505. Zhou, Ying
    et al.
    Li, Xing
    Li, Xin
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Chen, Jue
    Yu, Fengtao
    Hua, Jianli
    The Effect of Pyridyl Nitrogen Atom Position in Pyrido-[3,4-b]pyrazines in Donor-Acceptor-pi-Acceptor Dyes on Absorption, Energy Levels, and Photovoltaic Performances of Dye-Sensitized Solar Cells2016Ingår i: ASIAN JOURNAL OF ORGANIC CHEMISTRY, ISSN 2193-5807, Vol. 5, nr 2, s. 293-300Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A donor-acceptor-pi-acceptor (D-A-pi-A)-type organic dye (DTN-1) incorporating a pyrido[3,4-b]pyrazine (PP) unit with the pyridyl N atom adjacent to the anchoring group has been synthesized for use in dye-sensitized solar cells (DSSCs). The maximum absorption wavelength of DTN-1 was clearly red-shifted compared with dye DT-1, based on PP unit with the pyridyl N atom adjacent to the donor group. However, this change of structure has a negative effect on photovoltaic performances, and devices made with DTN-1 only reached a power conversion efficiency of 6.10% under AM1.5G irradiation compared with 8.57% achieved by DT-1. Density functional theory calculations suggest that DTN-1 has a smaller oscillator strength, which is connected to its relatively low light-harvesting efficiency. In addition, the results of electrochemical impedance spectroscopy (EIS) reveal that charge recombination in DSSCs based on DTN-1 is more than that in the counterpart DT-1, thus leading to a lower open-circuit voltage (V-oc).

  • 122506. Zhou, Yong
    et al.
    Miao, Quan
    Sun, Yuping
    Gelmukhanov, Faris
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi.
    Wang, Chuan-Kui
    Solvent effect on dynamical TPA and optical limiting of BDMAS molecular media for nanosecond and femtosecond laser pulses2011Ingår i: Journal of Physics B: Atomic, Molecular and Optical Physics, ISSN 0953-4075, E-ISSN 1361-6455, Vol. 44, nr 3, s. 035103-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The dynamical two-photon absorption (TPA) cross section as well as optical limiting of a 4,4'-bis(dimethylamino) stilbene (BDMAS) molecular medium for the nanosecond and femtosecond laser pulses is studied. This molecular medium can be described by a cascade three-level model in the visible light regime. Our numerical results show that the BDMAS molecular medium exhibits a strong optical limiting behaviour. The saturation TPA in the femtosecond time domain can be observed, and materials with larger nonlinear absorption cross sections would be much easier to saturate. Due to the contribution of the two-step TPA, the dynamical TPA cross section of BDMAS for nanosecond pulses is about three orders of magnitude larger than that for ultrashort femtosecond pulses. Special attention has been paid to the solvent effects on the optimal limiting performance. With an enhancement of the polarity of solvents, the dynamical optical limiting window becomes broader. In the origin of optical limiting, the dynamical TPA cross section of BDMAS decreases when the polarity of solvents increases, which is in good agreement with the experiment.

  • 122507. Zhou, Yongjin J.
    et al.
    Buijs, Nicolaas A.
    Zhu, Zhiwei
    Qin, Jiufu
    Siewers, Verena
    Nielsen, Jens
    KTH, Skolan för bioteknologi (BIO), Genteknologi.
    Production of fatty acid-derived oleochemicals and biofuels by synthetic yeast cell factories2016Ingår i: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 7, artikel-id 11709Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Sustainable production of oleochemicals requires establishment of cell factory platform strains. The yeast Saccharomyces cerevisiae is an attractive cell factory as new strains can be rapidly implemented into existing infrastructures such as bioethanol production plants. Here we show high-level production of free fatty acids (FFAs) in a yeast cell factory, and the production of alkanes and fatty alcohols from its descendants. The engineered strain produces up to 10.4 gl(-1) of FFAs, which is the highest reported titre to date. Furthermore, through screening of specific pathway enzymes, endogenous alcohol dehydrogenases and aldehyde reductases, we reconstruct efficient pathways for conversion of fatty acids to alkanes (0.8 mgl(-1)) and fatty alcohols (1.5 gl(-1)), to our knowledge the highest titres reported in S. cerevisiae. This should facilitate the construction of yeast cell factories for production of fatty acids derived products and even aldehyde-derived chemicals of high value.

  • 122508.
    Zhou, You
    et al.
    Huazhong Univ Sci & Technol, Sch Opt & Elect Informat, Wuhan, Hubei, Peoples R China.;Huazhong Univ Sci & Technol, Wuhan Natl Lab Optoelect, Wuhan, Hubei, Peoples R China..
    Wu, Fei
    Huazhong Univ Sci & Technol, Wuhan Natl Lab Optoelect, Wuhan, Hubei, Peoples R China..
    Lu, Zhonghai
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik.
    He, Xubin
    Temple Univ, Dept Comp & Informat Sci, Philadelphia, PA 19122 USA..
    Huang, Ping
    Temple Univ, Dept Comp & Informat Sci, Philadelphia, PA 19122 USA..
    Xie, Changsheng
    Huazhong Univ Sci & Technol, Wuhan Natl Lab Optoelect, Wuhan, Hubei, Peoples R China..
    SCORE: A Novel Scheme to Efficiently Cache Overlong ECCs in NAND Flash Memory2019Ingår i: ACM Transactions on Architecture and Code Optimization (TACO), ISSN 1544-3566, E-ISSN 1544-3973, Vol. 15, nr 4, artikel-id 60Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Technology scaling and program/erase cycling result in an increasing bit error rate in NAND flash storage. Some solid state drives (SSDs) adopt overlong error correction codes (ECCs), whose redundancy size exceeds the spare area limit of flash pages, to protect user data for improved reliability and lifetime. However, the read performance is significantly degraded, because a logical data page and its ECC redundancy are stored in two flash pages. In this article, we find that caching ECCs has a large potential to reduce flash reads by achieving higher hit rates, compared to caching data. Then, we propose a novel scheme to efficiently cache overlong ECCs, called SCORE, to improve the SSD performance. Exceeding ECC redundancy (called ECC residues) of logically consecutive data pages are grouped into ECC pages. SCORE partitions RAM to cache both data pages and ECC pages in a workload-adaptive manner. Finally, we verify SCORE using extensive trace-driven simulations. The results show that SCORE obtains high ECC hit rates without sacrificing data hit rates, thus improving the read performance by an average of 22% under various workloads, compared to the state-of-the-art schemes.

  • 122509.
    Zhou, Yufeng
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Performance Evaluation of a Weighted Clustering Algorithm in NSPS Scenarios2013Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    In national security and public safety (NSPS) scenarios, the concept of device-to-device (D2D) clustering allows user equipment (UEs) to dynamically form clusters and thereby allows for local communication with partial or no cellular network assistance. We propose and evaluate a clustering approach to solve this problem in this thesis report. One of the key components of clustering is the selection of so called cluster head (CH) nodes that are responsible for the formation of clusters and act as a synchronization and radio resource management information source. In this thesis work we propose a weighted CH selection algorithm that takes into account UE capability, mobility and other information and aims at balancing between energy efficiency, discovery rate and cluster formation time. Numerical results show that the clustering approach consumes more energy but it can achieve a much higher discovery rate and communication rate for the system. Simulation results indicate that the weighted clustering approach is a viable alternative in NSPS situations.

  • 122510.
    Zhou, Yukun
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Arkitektur, Stadsbyggnad.
    LANDSCAPE INTEGRATION IN URBAN CONTEXT: Landscape Regeneration of Slakthusområdet2012Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Taking as a starting point the theory and concept of Landscape Urbanism, this thesis project explores an alternative solution for the regeneration of old industrial areas using a case study: the design of Slakthusområdet in Stockholm. The project focuses on how to use landscape as a medium to transform Slakthusområdet into a sustainable, attractive, and people friendly area. And at the same time integrate it into a wider urban context. It covers two aspects: First, the integration of the site in the surrounding green network. Second, the regeneration of the green infrastructure inside of the site that could add ecological and social values to the site. 

  • 122511.
    Zhou, Yunyun
    et al.
    Fudan Univ, Dept Macromol Sci, State Key Lab Mol Engn Polymers, Shanghai 200433, Peoples R China..
    Baryshnikov, Gleb V.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Teoretisk kemi och biologi. Bogdan Khmelnitsky Natl Univ, Dept Chem & Nanomat Sci, UA-18031 Cherkassy, Ukraine..
    Li, Xuping
    Fudan Univ, Dept Macromol Sci, State Key Lab Mol Engn Polymers, Shanghai 200433, Peoples R China..
    Zhu, Mingjie
    Fudan Univ, Dept Macromol Sci, State Key Lab Mol Engn Polymers, Shanghai 200433, Peoples R China..
    Ågren, Hans
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Teoretisk kemi och biologi. Uppsala Univ, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden..
    Zhu, Liangliang
    Fudan Univ, Dept Macromol Sci, State Key Lab Mol Engn Polymers, Shanghai 200433, Peoples R China..
    Anti-Kasha's Rule Emissive Switching Induced by Intermolecular H-Bonding2018Ingår i: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 30, nr 21, s. 8008-8016Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The exploration of emission pathways from high-excited states in organic luminogens has recently become prosperous owing to improved possibilities to study so-called anti-Kasha's rule emission with the potential of improving the luminescent quantum efficiency. However, emission pathway switching among different high-excited states has rarely been addressed through external control. We here present a rational design and synthesis of a novel azulene-based emitter to achieve a responsive control of its anti-Kasha's rule emissive switching. The emitter initially gives rise to an S-3-to-S-0 dominant emission as indicated by our experimental and theoretical studies. On this basis, it can be toggled into an S-2-to-S-0 dominant emission upon the H-bond formation between the triformyl groups and water molecules. Such a process, which originates from the H-bonding regulated distribution of excited state energy, is accompanied by a remarkable fluorescent color conversion and a significant improvement of the fluorescent quantum yield in the azulene family. Moreover, a reversible emissive switching in doped films was observed to depend on a solid-state H-bond tuning process with moisture sensitivity. These results may provide new insight for building advanced chemical systems for visualized sensing with high distinguishability.

  • 122512. Zhou, Yunyun
    et al.
    Zhuang, Yaping
    Li, Xin
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Ågren, Hans
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Yu, Lin
    Ding, Jiandong
    Zhu, Liangliang
    Selective Dual-Channel Imaging on Cyanostyryl-Modified Azulene Systems with Unimolecularly Tunable Visible-Near Infrared Luminescence2017Ingår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 23, nr 32, s. 7642-7647Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Although organic light-emitting molecules have received a growing attention and applicability in modern bioimaging science, the design and control of complex photoluminescent properties in unimolecularly selective imaging remains a challenging topic. Considering that tunable multipathway imaging can be advantagedly connected with treatment processes in therapy, the integration of an azulene and a cyanostyryl moiety into one skeleton is carried out for the generation of in situ stimuli-responsive luminescent materials, with the aim to achieve tunable and effective emissions in distinct channels through smart molecular design on a single-molecular platform. This strategy takes advantage of 1) the Z/E isomerization of the cyanostyryl unit that can vary the push-pull effect of the substitution on azulene, accompanied by altering absorption and emission of individual excited states, and 2) an optimized excited-state regulation for opening a near infrared emissive channel and making up for a controllable dual-pathway luminescent system together with the utilization of visible emission. As exemplified by a demonstration of manipulating the luminescence at the cell level, the materials exhibit a superior application potential for unimolecularly selective imaging, labeling and probing events.

  • 122513.
    Zhou, Yushan
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Fusionsplasmafysik.
    Impact of Surface Structures onDeposition and Erosion in a Tokamak2019Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Fusion är en potentiellt obegränsad och miljövänlig energikälla för det mänskliga samhället i framtiden. Det återstår emellertid vissa problem att lösa. Bland dem är deposition och erosion vid ytor som är i kontakt med plasmat kritiska. Deposition av bränsle och föroreningar ger potentiellt långsiktig ackumulation av bränsle (tritium) som kan ge upphov till säkerhetsproblem och försämra bränsleekonomin. Erosion av vakuumkärlets väggar i in fusionsanläggning alstrar förorenar plasmat och kan begränsa livstiden för väggkomponenter. Arbetet i denna avhandling fokuserar på deposition och erosion på ytor i JET-ILW-projektet, som består av volfram (eller volframbelagd kolfiberkomposit) i divertor och beryllium i limiter.

    För depositionsfrågorna användes mikroanalys för att observera hur deuterium och beryllium fördelas över ytorna efter plasmaexponering. Yttopografi erhölls från SEM, optisk mikroskopi och konfokal laserskanmikroskopi. Distributionskartor från IBA jämfördes med yttopografin. För att förklara experimentella resultat användes modellering av jontrajektorior, dels på verklig experimentell topografi, dels på förenklade modellytor. Micro IBA-resultat visar att deuterium och beryllium ansamlas i mikroskopiskt nedsänkta områden, t.ex. gropar och sprickor. Modelleringen visar att joners gyratation delvis kan förklara denna ojämna fördelning av deuterium och beryllium.

    För erosionsproblemet gjordes mätningar på markerplattor, konstruerade för att observera materialosion i JET. En ny metod införs för att erhålla erosionsdata, genom att kombinera mikro IBA och SEM-bild. Denna metod kan skilja på inflytande på IBA-resultat från skrovlighet, vilket är annars är ett problem IBA för på skrovlig yta. På samma sätt används mikroanalys för att förbättra tolkningen av analyser av deuterium som trängt in i en skiktad struktur.

  • 122514.
    Zhou, Yushan
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Fusionsplasmafysik.
    Bergsåker, Henric
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Fusionsplasmafysik.
    Bykov, Igor
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Fusionsplasmafysik.
    Petersson, Per
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Fusionsplasmafysik.
    Paneta, C.
    Possnert, G.
    Micro ion beam analysis for the erosion of beryllium marker tiles in a tokamak limiter2019Ingår i: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 450, s. 200-204Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Beryllium limiter marker tiles were exposed to plasma in the Joint European Torus to diagnose the erosion of main chamber wall materials. A limiter marker tile consists of a beryllium coating layer (7–9 μm) on the top of bulk beryllium, with a nickel interlayer (2–3 μm) between them. The thickness variation of the beryllium coating layer, after exposure to plasma, could indicate the erosion measured by ion beam analysis with backscattering spectrometry. However, interpretations from broad beam backscattering spectra were limited by the non-uniform surface structures. Therefore, micro-ion beam analysis (μ-IBA) with 3 MeV proton beam for Elastic backscattering spectrometry (EBS) and PIXE was used to scan samples. The spot size was in the range of 3–10 μm. Scanned areas were analysed with scanning electron microscopy (SEM) as well. Combining results from μ-IBA and SEM, we obtained local spectra from carefully chosen areas on which the surface structures were relatively uniform. Local spectra suggested that the scanned area (≈600 μm × 1200 μm) contained regions with serious erosion with only 2–3 μm coating beryllium left, regions with intact marker tile, and droplets with 90% beryllium. The nonuniform erosion, droplets mainly formed by beryllium, and the possible mixture of beryllium and nickel were the major reasons that confused interpretation from broad beam EBS.

  • 122515.
    Zhou, Yushan
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Fusionsplasmafysik.
    Bergsåker, Henric
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Fusionsplasmafysik.
    Bykov, Igor
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Fusionsplasmafysik.
    Petersson, Per
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Fusionsplasmafysik.
    Possnert, G.
    Likonen, J.
    Pettersson, J.
    Koivuranta, S.
    Widdowson, A. M.
    Microanalysis of deposited layers in the inner divertor of JET with ITER-like wall2017Ingår i: NUCLEAR MATERIALS AND ENERGY, ISSN 2352-1791, Vol. 12, s. 412-417Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In JET with ITER-like wall, beryllium eroded in the main chamber is transported to the divertor and deposited mainly at the horizontal surfaces of tiles 1 and 0 (high field gap closure, HFGC). These surfaces are tungsten coated carbon fibre composite (CFC). Surface sampleswere collected following the plasma operations in 2011-2012 and 2013-2014 respectively. The surfaces, as well as polished cross sections of the deposited layers at the surfaces have been studied with micro ion beam analysis methods (mu-IBA). Deposition of Beand other impurities, and retention of D is microscopically inhomogeneous. Impurities and trapped deuterium accumulate preferentially in cracks, pits and depressed regions, and at the sides of large pits in the substrate (e.g. arc tracks where the W coating has been removed). With careful overlaying of mu-NRA elemental maps with optical microscopy images, it is possible to separate surface roughness effects from depth profiles at microscopically flat surface regions.

  • 122516.
    Zhou, Yushan
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Fusionsplasmafysik.
    Bergsåker, Henric
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Fusionsplasmafysik.
    Petersson, Per
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Fusionsplasmafysik.
    Modelling of effect from rough surface on deuterium and beryllium deposition on divertor targetManuskript (preprint) (Övrigt vetenskapligt)
  • 122517.
    Zhou, Yushan
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Fusionsplasmafysik.
    Bergsåker, Henric
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Fusionsplasmafysik.
    Petersson, Per
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Fusionsplasmafysik.
    Possnert, G
    Likonen, J
    contributors, JET
    The effect of gyration on the deposition of beryllium and deuterium at rough surface on thedivertor tiles with ITER-like-wall in JET2019Ingår i: Nuclear Materials and Energy, E-ISSN 2352-1791Artikel i tidskrift (Refereegranskat)
  • 122518.
    Zhou, Yuye
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    Romson, Joakim
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    Emmer, Åsa
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    An antibody-free sample pretreatment method for osteopontin combined with MALDI-TOF MS/MS analysis2019Ingår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 14, nr 3, artikel-id e0213405Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Osteopontin is an osteoblast-secreted protein with an aspartic acid-rich, highly phosphorylated, and glycosylated structure. Osteopontin can easily bind to integrins, tumor cells, extracellular matrix and calcium, and is related to bone diseases, various cancers, inflammation etc. Here, DEAE-Cibacron blue 3GA was used to extract recombinant osteopontin from human plasma, and to deplete abundant plasma proteins with an antibody-free method. Using selected buffer systems, osteopontin and human serum albumin could be bound to DEAE-Cibacron blue 3GA, while immunoglobulin G was excluded. The bound osteopontin could then be separated from albumin by using different sequential elution buffers. By this method, 1 μg/mL recombinant osteopontin could be separated from the major part of the most abundant proteins in human plasma. After trypsin digestion, the extracted osteopontin could be successfully detected and identified by MALDI-TOF MS/MS using the m/z 1854.898 peptide and its fragments.

  • 122519. Zhou, Z. -Q
    et al.
    Liu, X.
    Kedem, Yaron
    KTH, Centra, Nordic Institute for Theoretical Physics NORDITA.
    Cui, J. -M
    Li, Z. -F
    Hua, Y. -L
    Li, C. -F
    Guo, G. -C
    Experimental observation of anomalous trajectories of single photons2017Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 95, nr 4, artikel-id 042121Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A century after its conception, quantum mechanics still hold surprises that contradict many "common sense" notions. The contradiction is especially sharp in case one consider trajectories of truly quantum objects such as single photons. From a classical point of view, trajectories are well defined for particles, but not for waves. The wave-particle duality forces a breakdown of this dichotomy and quantum mechanics resolves this in a remarkable way: Trajectories can be well defined, but they are utterly different from classical trajectories. Here, we give an operational definition to the trajectory of a single photon by introducing a technique to mark its path using its spectral composition. The method demonstrates that the frequency degree of freedom can be used as a bona fide quantum measurement device (meter). The analysis of a number of setups, using our operational definition, leads to anomalous trajectories which are noncontinuous and in some cases do not even connect the source of the photon to where it is detected. We carried out an experimental demonstration of these anomalous trajectories using a nested interferometer. We show that the two-state vector formalism provides a simple explanation for the results. © 2017 American Physical Society.

  • 122520.
    Zhou, Zhou
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Neuronik.
    Li, Xiaogai
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Neuronik.
    Kleiven, Svein
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Neuronik.
    Biomechanics of acute subdural hematoma in the elderly: A fluid-structure interaction study2019Ingår i: Journal of Neurotrauma, ISSN 0897-7151, E-ISSN 1557-9042, Vol. 36, nr 13, s. 2099-2108Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Acute subdural hematoma (ASDH) due to bridging vein (BV) rupture is a frequent and lethal head injury, especially in the elderly. Brain atrophy has been hypothesized to be a primary pathogenesis associated with the increased risk of ASDH in the elderly. Though decades of biomechanical endeavours have been made to elucidate the potential mechanisms, a thorough explanation for this hypothesis appears lacking. Thus, a recently improved finite element head model, in which the brain-skull interface was modelled using a fluid-structure interaction (FSI) approach with special treatment of the cerebrospinal fluid as arbitrary Lagrangian-Eulerian fluid formulation, is used to partially address this understanding gap. Models with various degrees of atrophied brains and thereby different subarachnoid thicknesses are generated and subsequently exposed to experimentally determined loadings known to cause ASDH or not. The results show significant increases in the cortical relative motion and BV strain in the atrophied brain, which consequently exacerbates the ASDH risk in the elderly. Results of this study are suggested to be considered while developing age-adapted protecting strategies for the elderly in the future.

  • 122521.
    Zhou, Zhou
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Neuronik.
    Li, Xiaogai
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Neuronik.
    Kleiven, Svein
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Neuronik.
    Fluid–structure interaction simulation of the brain–skull interface for acute subdural haematoma prediction2018Ingår i: Biomechanics and Modeling in Mechanobiology, ISSN 1617-7959, E-ISSN 1617-7940, Vol. 18, nr 1, s. 155-173Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Traumatic brain injury is a leading cause of disability and mortality. Finite element-based head models are promising tools for enhanced head injury prediction, mitigation and prevention. The reliability of such models depends heavily on adequate representation of the brain–skull interaction. Nevertheless, the brain–skull interface has been largely simplified in previous three-dimensional head models without accounting for the fluid behaviour of the cerebrospinal fluid (CSF) and its mechanical interaction with the brain and skull. In this study, the brain–skull interface in a previously developed head model is modified as a fluid–structure interaction (FSI) approach, in which the CSF is treated on a moving mesh using an arbitrary Lagrangian–Eulerian multi-material formulation and the brain on a deformable mesh using a Lagrangian formulation. The modified model is validated against brain–skull relative displacement and intracranial pressure responses and subsequently imposed to an experimentally determined loading known to cause acute subdural haematoma (ASDH). Compared to the original model, the modified model achieves an improved validation performance in terms of brain–skull relative motion and is able to predict the occurrence of ASDH more accurately, indicating the superiority of the FSI approach for brain–skull interface modelling. The introduction of the FSI approach to represent the fluid behaviour of the CSF and its interaction with the brain and skull is crucial for more accurate head injury predictions.

  • 122522.
    Zhou, Zhou
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Neuronik.
    Li, Xiaogai
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Neuronik.
    Kleiven, Svein
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Neuronik.
    Shah, C.S.
    Hardy, W.N.
    A reanalysis of experimental brain strain data: implication for finite element head model validation2018Ingår i: Stapp Car Crash Journal, ISSN 1532-8546, Vol. 62, s. 293-318Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Relative motion between the brain and skull and brain deformation are biomechanics aspects associated with many types of traumatic brain injury (TBI). Thus far, there is only one experimental endeavor (Hardy et al., 2007) reported brain strain under loading conditions commensurate with levels that were capable of producing injury. Most of the existing finite element (FE) head models are validated against brain-skull relative motion and then used for TBI prediction based on strain metrics. However, the suitability of using a model validated against brain-skull relative motion for strain prediction remains to be determined. To partially address the deficiency of experimental brain deformation data, this study revisits the only existing dynamic experimental brain strain data and updates the original calculations, which reflect incremental strain changes. The brain strain is recomputed by imposing the measured motion of neutral density target (NDT) to the NDT triad model. The revised brain strain and the brain-skull relative motion data are then used to test the hypothesis that an FE head model validated against brainskull relative motion does not guarantee its accuracy in terms of brain strain prediction. To this end, responses of brain strain and brain-skull relative motion of a previously developed FE head model (Kleiven, 2007) are compared with available experimental data. CORrelation and Analysis (CORA) and Normalized Integral Square Error (NISE) are employed to evaluate model validation performance for both brain strain and brain-skull relative motion. Correlation analyses (Pearson coefficient) are conducted between average cluster peak strain and average cluster peak brain-skull relative motion, and also between brain strain validation scores and brain-skull relative motion validation scores. The results show no significant correlations, neither between experimentally acquired peaks nor between computationally determined validation scores. These findings indicate that a head model validated against brain-skull relative motion may not be sufficient to assure its strain prediction accuracy. It is suggested that a FE head model with intended use for strain prediction should be validated against the experimental brain deformation data and not just the brain-skull relative motion.

  • 122523. Zhou, Zude
    et al.
    Yao, Bitao
    Xu, Wenjun
    Wang, Lihui
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion, Produktionssystem.
    Condition monitoring towards energy-efficient manufacturing: a review2017Ingår i: The International Journal of Advanced Manufacturing Technology, ISSN 0268-3768, E-ISSN 1433-3015, Vol. 91, nr 9-12, s. 3395-3415Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Recently, sustainable development has obtained increasing attentions from governments, industry, and academia owing to the limited natural resources. In the area of energy consumption, manufacturing accounts for a major portion of the total energy usage in industry. There is a clear necessity for energy-efficient manufacturing by optimizing manufacturing activities. Condition monitoring is the technology that provides runtime information for optimization. This paper aims to provide a better understanding of past achievements and future trends of condition monitoring towards energy-efficient manufacturing. Since there are a variety of sensors and technologies that can be used for condition monitoring towards energy-efficient manufacturing, this paper divides manufacturing activities into three levels, namely unit process level, shop-floor level, and supply chain level, and summarizes and discusses the sensors and technologies required to enable energy-efficient manufacturing on each level. With the advancement of technology, condition monitoring shows the characteristic of intelligence. Intelligent sensors that can be applied to condition monitoring in energy-efficient manufacturing are also reviewed. This paper can be helpful to manufacturers who are willing to improve energy efficiency in own manufacturing practice.

  • 122524.
    Zhovtobriukh, Iurii
    et al.
    Stockholm Univ, FYSIKUM, AlbaNova Univ Ctr, SE-10691 Stockholm, Sweden..
    Norman, Patrick
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Teoretisk kemi och biologi.
    Pettersson, Lars G. M.
    Stockholm Univ, FYSIKUM, AlbaNova Univ Ctr, SE-10691 Stockholm, Sweden..
    X-ray absorption spectrum simulations of hexagonal ice2019Ingår i: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 150, nr 3, artikel-id 034501Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We calibrate basis sets and performance of two theoretical approaches to compute X-ray absorption spectra (XAS) of condensed water by comparison to experiments on hexagonal ice Ih. We apply both the transition-potential half-core-hole approach and the complex polarization propagator using four different models of the crystal with increasing oxygen and proton disorder but find poor agreement with experiments. We note that there are large variations in experimental spectra depending on detection mode and how the ice samples were prepared, which leads us to critically investigate what structures were actually prepared and measured in each case. This is done by using a Monte Carlo-based fitting technique which fits the spectra based on a library of precomputed spectra and assigns weights to contributions from different model structures. These are then used to generate O-O and O-H radial distribution functions and tetrahedrality parameters associated with each of the measured spectra. We find that all spectra are associated with sharp peaks at the oxygen positions in the perfect lattice, but with significant disorder around these positions. We suggest that presently available XAS of hexagonal ice are not fully representative of the perfect crystalline lattice, but contain varying amounts of defects and possible contributions from low-density amorphous ice.

  • 122525. Zhow, Yongjin J.
    et al.
    Buijs, Nicolaas A.
    Zhu, Zhiwei
    Gomez, Diego Orol
    Boonsombuti, Akarin
    Siewers, Verena
    Nielsen, Jens
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab. Chalmers University of Technology, Sweden; Technical University of Denmark, Denmark.
    Harnessing Yeast Peroxisomes for Biosynthesis of Fatty-Acid-Derived Biofuels and Chemicals with Relieved Side-Pathway Competition2016Ingår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 138, nr 47, s. 15368-15377Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Establishing efficient synthetic pathways for microbial production of biochemicals is often hampered by competing pathways and/or insufficient precursor supply. Compartmentalization in cellular organelles can isolate synthetic pathways from competing pathways, and provide a compact and suitable environment for biosynthesis. Peroxisomes are cellular organelles where fatty acids are degraded, a process that is inhibited under typical fermentation conditions making them an interesting workhouse for production of fatty-acid-derived molecules. Here, we show that targeting synthetic pathways to peroxisomes can increase the production of fatty-acid-derived fatty alcohols, alkanes and olefins up to 700%. In addition, we demonstrate that biosynthesis of these chemicals in the peroxisomes results in significantly decreased accumulation of byproducts formed by competing enzymes. We further demonstrate that production can be enhanced up to 3-fold by increasing the peroxisome population. The strategies described here could be used for production of other chemicals, especially acyl-CoA-derived molecules.

  • 122526.
    Zhu, Anlin
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    Railway Infrastructure Management - System Engineering and Requirement Management2017Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Rail Control Solutions (RCS) är en del av Bombardier Transportation, som syftar till att optimera flödet av tåg. OPTIFLO är ett nytt programspaket inom RCS, som erbjuder tjänster och lösningar för att hantera utmaningar inom modern järnvägsinfrastruktur världen över. Infrastrucutre Management (IM) Service är en viktig delmodul under OPTIFLO, som utför övervakning och diagnostiska funktioner för varje påverkat system eller komponent i järnvägssignalsystem för att kontinuerligt förbättra säkerhet, tillförlitlighet och tillgänglighet.

    Kravhantering är ett viktigt steg när man arbetar med tekniska problem. Det här mastersprojektet är inriktat på tre moduler inom järnvägssignalområdet: systemnivå Infrastructure Management, underhållssystem för Maintenance and Diagnostic Centre (MDC) och delsystemnivå Remote Sensor Unit (RSU). För varje del har kravhantering implementerats, med hänvisning till CENELEC-standarder vid behov. Arbetet har utgått från utkast till kravspecifikation för IM och identifierat kraven för diagnostik och prestanda i varje delsystem. Både kopplingar mellan kraven i olika moduler och kopplingar mellan kraven och deras testfall är byggda i systemet DOORS för att realisera verifiering och validering i en systemteknisk process. Slutligen släpps standarddokumentationen "Systemkrav Specifikation" för de moduler som behandlar i detta arbete.

  • 122527.
    Zhu, Anqing
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Arkitektur.
    Translation From Image to Building2012Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    After the fire accident, KTH school of architecture is no longer in its best performance. The school indeed need an extension. However, through out this thesis project, I attempt to take one step further. It is not only to construct a functional school, but reconsider the meaning of architectural education. I am interested in three aspects, which all of them has being driving forces to this project. Firstly, I was interested in memory of the old architecture school in Stockholm, which was accommodated in a 19th centry wooden building. It was old and small, but students loved it. One’s memory of certain places would shape his thinking and values as an architect. Therefore, my design attempts to bring back such a memory by study some of the details in the old building and bring them back into the new extension with a twist. Secondly, in terms of working method I am very much resisted to ‘Graphic Architecture’, models always come together with rending images. They are offered to read side by side. The rending images are not trying to present the final products but also used as a development tool. Overall this project was developed from the inside towards the outside. The aim was to make an ordinary building with some thoughtful touches.

  • 122528. Zhu, B.
    et al.
    Fan, L.
    Deng, H.
    He, Y.
    Afzal, M.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Dong, W.
    Yaqub, A.
    Janjua, N. K.
    Erratum: Corrigendum to “LiNiFe-based layered structure oxide and composite for advanced single layer fuel cells” (J. Power Sources (2016) 316 (37–43))2016Ingår i: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 324Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The authors regret that the name of author Yunjuan He was misspelled as ‘Yunjune He’ in the original article. The authors would like to apologise for any inconvenience caused.

  • 122529.
    Zhu, B.
    et al.
    KTH, Skolan för datavetenskap och kommunikation (CSC), Medieteknik och interaktionsdesign, MID.
    Hedman, Anders
    KTH, Skolan för datavetenskap och kommunikation (CSC), Medieteknik och interaktionsdesign, MID.
    Li, Haibo
    KTH, Skolan för datavetenskap och kommunikation (CSC), Medieteknik och interaktionsdesign, MID.
    Design digital mindfulness for personal wellbeing2016Ingår i: Proceedings of the 28th Australian Computer-Human Interaction Conference, OzCHI 2016, Association for Computing Machinery, Inc , 2016, s. 626-627Konferensbidrag (Refereegranskat)
    Abstract [en]

    The digital health and wellbeing movement has led to development of what we here baptize as digital mindfulness applications that allow people to improve psychological wellbeing. The approaches to digital mindfulness vary greatly and as a researcher it can be difficult to gain an overview of the field and what to focus on in one's own research. Here we describe four levels of digital mindfulness with examples and focus on the larger question of how to design for digital mindfulness. We end up with a set of general issues that we hope will generate further discussion and research in the field of digital mindfulness. 

  • 122530. Zhu, B.
    et al.
    Lindbergh, Göran
    KTH, Tidigare Institutioner                               , Kemiteknik.
    Corrosion behaviour of high-chromium ferritic steels in molten carbonate in cathode environment2001Ingår i: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 46, nr 17, s. 2593-2604Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The corrosion behaviour of four ferritic steels with a high chromium content and AISI 310 was investigated in (Li-0.60/Na-0.40)(2)CO3 melt in three different cathode gas environments. The electrochemical techniques used were linear polarisation resistance and Tafel extrapolation. The corrosion layers formed on the surface during the tests were analysed by glow discharge optical emission spectroscopy (GDOES), The corrosion layer formed on the Thermax 4762 sample consists of an iron-rich outer layer and a protective aluminium- and chromium-rich inner layer. The corrosion potential increased to a more positive value as the corrosion layer grew on the surface. This supports the supposition that the cathodic reaction in the corrosion process changes gradually from water reduction to oxygen reduction. It was shown that higher temperatures and low concentrations of oxygen and carbon dioxide under so-called outlet cathode gas conditions result in higher corrosion rates.

  • 122531. Zhu, B.
    et al.
    Lund, P. D.
    Raza, Rizwan
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik. COMSATS Institute of Information Technology, Pakistan .
    Ma, Y.
    Fan, L.
    Afzal, Muhammad
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Patakangas, J.
    He, Y.
    Zhao, Y.
    Tan, W.
    Huang, Q. -A
    Zhang, J.
    Wang, H.
    Schottky junction effect on high performance fuel cells based on nanocomposite materials2015Ingår i: Advanced Energy Materials, ISSN 1614-6832, Vol. 5, nr 8, artikel-id 1401895Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A novel fuel cell device based on integrating the Schottky junction effect with the electrochemical principle is designed, constructed, and verified through experiments. It is found that the Schottky junction has a significant effect on the greatly enhanced device performance, and the fuel cell device incorporating the Schottky junction effect reaches a power output of 1000 mW cm-2 at 550 C.

  • 122532. Zhu, B.
    et al.
    Lv, F.
    Ma, D.
    Zhou, Helin
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    A pocket discharge model for narrow bipolar events and possible applications2010Ingår i: 2010 Asia-Pacific Symposium on Electromagnetic Compatibility, APEMC 2010, 2010, s. 1558-1561Konferensbidrag (Refereegranskat)
    Abstract [en]

    Narrow bipolar events refer to a distinct type of in-cloud lightning discharge which produces electric field of bipolar and impulse in nature. In this presentation narrow bipolar events were considered as the discharge of the pocket charge to the charge layer inside thundercloud, and the current wave-shape possibly responsible for the narrow bipolar electromagnetic field was featured by two channel-conducting-state depended parameters (α,β). The parameter β inversely reflects the time for the current front to propagate along the channel and can be achieved by the perfect fit of the measured field waveform to the model field waveform with the channel length and current propagation speed bound by the parameter β. The present model was applied to the narrow bipolar fields of two narrow bipolar events to reach a parameter β of 0.333μs-1 and 0.353μs-1 respectively, indicating a channel length less than 1km.

  • 122533. Zhu, B.
    et al.
    Zhou, Helin
    University of Science and Technology of China, Hefei, Anhui, China.
    Ma, M.
    Lv, F.
    Tao, S.
    Estimation of channel characteristics of narrow bipolar events based on the transmission-line model2010Ingår i: Journal of Geophysical Research, ISSN 0148-0227, E-ISSN 2156-2202, Vol. 115, nr 19, s. D19105-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Narrow bipolar event (NBE) is a distinct class of intracloud lightning discharge, which is associated with the strongest radio frequency emissions and produces typical narrow bipolar radiation field waveforms. On the basis of the transmission-line model, we introduce a direct technique to measure the time taken by the current front to propagate along the channel from distant radiation field pulses; the channel length of the NBE can then be estimated by multiplying this time by an assumed propagation speed. Our method involves integrating over the initial half cycle of narrow bipolar waveform of the NBE. The ratio of the integral result to the initial peak amplitude makes a good approximation to the time taken by the current front to travel along the channel, even though the current amplitude suffers heavy attenuation along the propagating channel. This method can be applied to all NBEs which produce narrow bipolar radiation field waveforms. Besides, if both the far radiation field and the near-electrostatic field measurements were available, one could combine the method here and that of Eack (2004) to obtain the channel length of the NBE.

  • 122534.
    Zhu, Baohua
    KTH, Tidigare Institutioner                               , Kemiteknik.
    Corrosion of current cullector materials in the molten carbonate fuel cell2000Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The corrosion of current collector materials in MoltenCarbonate Fuel Cells (MCFC) is investigated. The essential aimsof this investigation were to study the corrosion behaviour ofdifferent materials, in varying cathode and anode MCFCenvironments, and to study the contact corrosion resistancesbetween the MCFC current collector and electrodes. For thesepurposes, pure iron, iron-chromium binary alloys and severalcommercial steels were investigated in molten carbonate meltswithin the pot-cell laboratory set-up. In addition, the contactcorrosion resistances, between an AISI 310 current collectorand two cathodes (NiO and LiCoO2), were studied in a laboratory fuel cell.Post-tests were done to study the corrosion products formed atthe surfaces.

    In cathode environments, corrosion potential increased overtime as a protective corrosion layer slowly formed. Eventually,the potential reached a stable value close to the cathodeoperating potential. The main cathode reaction, as corrosionpotential increased, changed from water reduction to oxygenreduction. Corrosion rate under the operating cathode conditiondepended on the chromium content; the higher the concentrationof chromium, the lower the corrosion rate. The corrosion ratesof ferritic steels, with high chromium content, and AISI 310were higher at the so-called outlet operating condition incomparison to the standard and so-called inlet conditions. Thecorrosion rate was higher at the beginning of the exposure,which resulted in a relatively fast corrosion layer growth thatslowed as the protective layer was formed. It was shown thatthe corrosion layers, formed on iron-chromium alloys, AISI 310and ferritic high chromium-containing steels, consisted of twolayers. The outer layer was porous and iron rich, while theinner layer was quite compact and rich in chromium and/oraluminiumTherefore, the corrosion behaviour was dependent onthe corrosion layer structure at the metal surface.

    In anode environments, the beneficial behaviour of aluminiumin ferritic alloys, with high aluminium contents, was due tothe formation of aluminium oxide and/or lithium aluminium oxideat the surface. The corrosion rates at the standard and outletconditions were of the same order of magnitude, while thecorrosion rates at the inlet conditions were considerablyhigher. The lower temperatures and higher carbon dioxideconcentrations in the inlet conditions appeared to result in asurface layer deficient in aluminium. A modified theoreticalmodel was developed to evaluate the corrosion current densitiesfrom experimental polarisation curves or linear polarisationresistance measurements in anode environments. The fittingswere found to be very good.

    An experimental method was developed forin-situmeasurements of the contributions to the totalohmic losses at the cathode in a laboratory scale MCFC. Thecontact resistance between the cathode and current collectorcontributed quite a large value to the total cathodepolarization. The corrosion layer, formed between the LiCoO2cathode and AISI 310 current collector, wasiron-rich and more porous, and contained a small amount ofcobalt. This was deemed to consist of a two-phase oxide, whichresulted in a lower conductivity. The corrosion layer, formedbetween the NiO cathode and AISI 310 current collector, wasrich in nickel. The corrosion layers on the AISI 310, incontact with the cathode, had a different composition comparedto samples immersed in carbonate melts.

    Key words: molten carbonate fuel cell (MCFC), corrosion,current collector, contact corrosion resistance.

  • 122535.
    Zhu, Baohua
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik.
    Lindbergh, Göran
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik.
    Simonsson, Daniel
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik.
    Comparison of electrochemical and surface characterisation methods for investigation of corrosion of bipolar plate materials in molten carbonate fuel cell Part I. Electrochemical study1999Ingår i: Corrosion Science, Vol. 41, nr 8, s. 1497-1513Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The corrosion of bipolar plate and current collector materials in molten carbonate fuel cells (MCFC) was investigated. Tafel extrapolation, linear polarisation resistance, chronopotentiometry and electrochemical impedance spectroscopy (EIS) were used to determine corrosion rates of iron and iron-based alloys in molten carbonate melts for both cathode and anode MCFC environments. During the initial stages, agreement among the methods was good but could have differed after a corrosion layer formed on the surface. The corrosion rate for a fully immersed sample at the open circuit potential seemed to be controlled by external mass transfer of water. Iron-chromium alloys exhibit reasonable corrosion resistance on the cathode side, provided that the chromium concentration exceeds 25%. The corrosion of bipolar plate and current collector materials in molten carbonate fuel cells (MCFC) was investigated. Tafel extrapolation, linear polarisation resistance, chronopotentiometry and electrochemical impedance spectroscopy (EIS) were used to determine corrosion rates of iron and iron-based alloys in molten carbonate melts for both cathode and anode MCFC environments. During the initial stages, agreement among the methods was good but could have differed after a corrosion layer formed on the surface. The corrosion rate for a fully immersed sample at the open circuit potential seemed to be controlled by external mass transfer of water. Iron-chromium alloys exhibit reasonable corrosion resistance on the cathode side, provided that the chromium concentration exceeds 25%.

  • 122536.
    Zhu, Baohua
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik.
    Lindbergh, Göran
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik.
    Simonsson, Daniel
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik.
    Comparison of electrochemical and surface characterisation methods for investigation of corrosion of bipolar plate materials in molten carbonate fuel cell Part II. Surface analysis1999Ingår i: Corrosion Science, Vol. 41, nr 8, s. 1515-1528Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The corrosion of bipolar plate materials in molten carbonate fuel cells (MCFC) was studied by electrochemical techniques. These methods were complemented by thermogravimetric analysis (TGA) and surface analyses, such as SEM, EDX and XRD. The concentration profiles of oxygen, lithium, iron, chromium and nickel in the oxide scales were determined by means of glow discharge optical emission spectroscopy (GDOES). It has been shown that corrosion layers, formed on the iron-chromium and stainless steels surfaces, consist of two layers. The outer layer is porous and has large pores; the inner layer is more compact and may contain small pores. The corrosion of bipolar plate materials in molten carbonate fuel cells (MCFC) was studied by electrochemical techniques. These methods were complemented by thermogravimetric analysis (TGA) and surface analyses, such as SEM, EDX and XRD. The concentration profiles of oxygen, lithium, iron, chromium and nickel in the oxide scales were determined by means of glow discharge optical emission spectroscopy (GDOES). It has been shown that corrosion layers, formed on the iron-chromium and stainless steels surfaces, consist of two layers. The outer layer is porous and has large pores; the inner layer is more compact and may contain small pores.

  • 122537. Zhu, Baoyou
    et al.
    Zhou, Helin
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Thottappillil, Rajeev
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Rakov, Vladimir A.
    Simultaneous observations of electric field changes, wideband magnetic field pulses, and VHF emissions associated with K processes in lightning discharges2014Ingår i: Journal of Geophysical Research D: Atmospheres, ISSN 2169-897X, Vol. 119, nr 6, s. 2699-2710Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We studied simultaneous electric field changes, microsecond-scale (VLF/LF) magnetic field pulses, and VHF emissions associated with K processes in 37 cloud and 54 cloud-to-ground lightning flashes that occurred in a local convective thunderstorm in Shanghai. All the observed features were very similar for both types of flashes. Over 98% of the 1252 observed K changes were associated with detectable microsecond-scale pulses, although only about 26% of them were accompanied by large pulses whose amplitude exceeds by at least 50% the average amplitude of the five largest pulses in the flash. VHF bursts, which almost always coincide in time with microsecond-scale pulses, can occur either during K changes or during the gaps between K changes. About 9% of K changes were observed to be associated with regular pulse trains, with pulses in the train showing one-to-one correspondence to VHF bursts and occurring at a geometric mean interval of 6.9 mu s. Overall, our results indicate that small microsecond-scale pulses are an inherent feature of K processes. We infer that the K process can be viewed as a fast negative leader, but only those leaders with appreciable charge transfer show step/ramp-like K changes in electric field records.

  • 122538.
    Zhu, Bin
    KTH, Tidigare Institutioner, Kemiteknik. Goeta Technol. Developer Intl, Sweden.
    Advanced ceramic fuel cell R&D2004Ingår i: Fuel Cell Science, Engineering and Technology - 2004, 2004, s. 409-417Konferensbidrag (Refereegranskat)
    Abstract [en]

    Since many years in Swedish national research project and Swedish-Chinese research framework we have carried out advanced ceramic fuel cell research and development, targeting for intermediate and low temperature ceramic or solid oxide fuel cells (ILTCFCs or ILTSOFCs, 300-700°C) based on ceramic-based composite materials. The ceramic composite material developments in Sweden have been experienced from the oxyacid-salts oxide proton-based conductors, non-oxide containment salts, the ceria-based composite electrolytes and nano-composites. Among them the ceria-based composites showed excellent ionic conductivity of 0.01 to 1 Scm-1 and ILTCFCs using these composites as electrolytes have achieved high performances of 200 to 1000 mWcm-2 at temperatures between 400 and 700°C. The excellent ion conduction was resulted from hybrid proton and oxygen ion conduction. The hybrid ion conduction and dual electrode reactions and processes create a new fuel cell system. Advanced ceramic fuel cell aims at developing a new generation to realize the challenges for fuel cell commercialization. This paper reviews our more than 14 years R&D on the field with emphasis on the recent progresses and achievements.

  • 122539.
    Zhu, Bin
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik.
    Advanced hybrid ion conducting ceramic composites and applications in new fuel cell generation2005Ingår i: HIGH-PERFORMANCE CERAMICS III, PTS 1 AND 2 / [ed] Pan, W; Gong, JH; Ge, CC; Li, JF, 2005, Vol. 280-283, s. 413-418Konferensbidrag (Refereegranskat)
    Abstract [en]

    Our developments on ceramic composite conductors have experienced about 15 years from the oxyacid-salts oxide proton-based conductors, non-oxide containment salts, the ceria-based composite electrolytes, hybrid proton and oxygen ion conductors and nano-composites. A special emphasis is paid to new functional nano-composites based on hybrid proton and oxygen ion conductors that have demonstrated advanced properties and fuel cell applications, e.g., excellent ionic conductivity of 0.01 to 1 Scm(-1) and performances of 200 - 1000 mWcm(-2) for temperatures achieved for fuel cells between 400 and 700degreesC. Some proton and oxygen ion conducting mechanisms in the materials are reviewed and discussed. The hybrid ion conduction and dual electrode reactions and processes create a new generation fuel cell system.

  • 122540.
    Zhu, Bin
    KTH, Tidigare Institutioner                               , Kemiteknik.
    Advantages of intermediate temperature solid oxide fuel cells for tractionary applications2001Ingår i: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 93, nr 02-jan, s. 82-86Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Our recent achievements suggest that intermediate temperature (IT) solid oxide fuel cells (SOFCs) can become a strong competitor not only for stationary power generation, but also for tractionary applications, e.g. for electrical (hybrid) vehicles. These ITSOFCs are based on ceria-salt composite ceramic materials. These new ceria-based composite ceramic materials have shown a super ionic conductivity (0.1-1.0 S cm(-1)) in the IT region (400-600 degreesC). Using them as the electrolytes the ITSOFCs are operated between 300 and 1500 mA cm(-2) (200-700 mW cm(-2)) continuously between 400 and 600 degreesC. The opportunities and advantages of these new advanced ITSOFCs for electrical vehicle applications are discussed. The high efficiency ITSOFCs fed directly with hydrocarbon containing gas-type and liquid-type fuels have shown an enormous potential for application in electrical vehicles.

  • 122541.
    Zhu, Bin
    KTH, Tidigare Institutioner                               , Kemiteknik.
    Applications of hydrofluoride ceramic membranes for advanced fuel cell technology2000Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 24, nr 1, s. 39-49Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    New types of materials, hydrofluoride-alumina ceramic composites containing one hydride component, CaH2, have been studied for fuel cell applications. Excellent fuel cell performances were achieved for a peak power density of 180 mW cm(-2) at 300 mA cm(-2), and a short-circuit current density near 1000 mA cm(-2). In fuel cell measurements the conductivity and ionic transport properties of the hydrofluoride-based electrolytes have also been investigated. During fuel cell operation, water was often observed at the cathode (air side), indicating that proton conduction occurs in these electrolyte materials. The experiments show an interesting chance for the future development of innovative fuel cell technology for commercialization.

  • 122542.
    Zhu, Bin
    KTH, Tidigare Institutioner                               , Kemiteknik.
    Functional ceria-salt-composite materials for advanced ITSOFC applications2003Ingår i: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 114, nr 1, s. 1-9Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper reports our current material research and development for advanced intermediate temperature (IT, 400-700 degreesC) solid oxide fuel cells (SOFCs). The materials reported in this work are based on ceria-salt-composites, which have super function, e.g. displaying ionic conductivity of 0.01-1 S cm(-1) in the IT region. They are functional ceramic materials for advanced ITSOFC applications. When these new composites are used as ITSOFC electrolytes, a performance of 300-800 mW cm(-2) between 400 and 650 degreesC has been demonstrated.

  • 122543.
    Zhu, Bin
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Nanocomposites for Advanced Fuel Cell Technology2011Ingår i: Journal of Nanoscience and Nanotechnology, ISSN 1533-4880, Vol. 11, nr 10, s. 8873-8879Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    NANOCOFC (Nanocomposites for advanced fuel cell technology) is a research platform/network established based on the FP6 EC-China project www.nanocofc.org. This paper reviews major achievements on two-phase nanocomposites for advanced low temperature (300-600 degrees C) solid oxide fuel cells (SOFCs), where the ceria-salt and ceria-oxide composites are common. A typical functional nanocomposite structure is a core-shell type, in which the ceria forms a core and the salt or another oxide form the shell layer. Both of them are in the nano-scale and the functional components. The high resolution TEM analysis has proven a clear interface in the ceria-based two-phase nanocomposites. such interface and interfacial function has resulted in superionic conductivity, above 0.1 S/cm at around 300 degrees C, being comparable to that of conventional SOFC YSZ at 1000 degrees C. Against conventional material design from the structure the advanced nanocomposites are designed by non-structure factors, i.e., the interfaces, and by creating interfacial functionalities between the two constituent phases. These new functional materials show indeed a breakthrough in the SOFC materials with great potential.

  • 122544.
    Zhu, Bin
    KTH, Tidigare Institutioner                               , Kemiteknik.
    New generation or universal fuel cell system? R&D for intermediate temperature solid oxide fuel cells (ITSOFCs)2001Ingår i: Journal of New Materials for Electrochemical Systems, ISSN 1480-2422, Vol. 4, nr 4, s. 239-251Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Present challenges forfuel cell (FC) commercialisation are related to the material and system limitations, delaying the FC market. Most intensive interests currently for the FCs are concentrated on the polymer electroyte fuel cells (PEFCs) and solid oxide fuel cells (SOFCs). Due to the material constraint the SOFC system has to be operated at high temperature, e.g., 1000 degreesC, resulting in expensive SOFC system and complex technology; while the noble platinum catalyst has to be used for the PEFCs, creating a bottleneck for its commercialisation. In addition, the PEFC system has limited applications due to a shortage of the fuel flexibility, e.g., for hydrocarbon fuels, existing commonly in present fuel infrastructure. There is therefore a need to develop new generation or universal FC system, which can be employed for various applications for both mobile, e.g., electrical vehicles, and stationary, e.g., power generation plant. These request an advanced FC system that should possess of the wide fuel flexibility, i.e., fitting to various present hydrocarbon fiiels, and most importantly, this FC system should be cost-effective and marketable. However the present FC systems themselves alone are difficult to meet these demands due to the, material and system limitations. Our strategy is to develop a new advanced or near universal FC system to combine technological advantage from present FC systems to create a new competitive vis-a-vis FC technology. To realise this strategy a key issue is addressed from the material point of view., This paper thus reviews recent developments/progresses and achievements/applications for R&D on the materials and ITSOFCs, more concerned on the new material-based ITSOFCs.

  • 122545.
    Zhu, Bin
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik.
    Next generation fuel cell R&D2006Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 30, nr 11, s. 895-903Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The material innovations and developments can play a key role in realizing solid oxide fuel cell (SOFC) commercialization. However, it seems missing in the long SOFC R&D strategy. Recent R&D. on innovative ceria-based composites (CBCs) make a breakthrough and open a new research subject on low-temperature (300-600 degrees C) SOFCs. Low temperatures create many freedoms to develop next generation fuel cell technology for commercialization.

  • 122546.
    Zhu, Bin
    KTH, Tidigare Institutioner                               , Kemiteknik.
    Proton and oxygen ion conduction in nonoxide ceramics2000Ingår i: Materials research bulletin, ISSN 0025-5408, E-ISSN 1873-4227, Vol. 35, nr 1, s. 47-52Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    By directly examining fuel cell performances, it was discovered that nonoxide containing materials such as chlorides and fluorides exhibit significant proton and oxygen ion conduction. Ionic transport measurements showed that both proton and oxygen ion conduction are present, with proton conduction predominant in most cases. Steady-state current output under fuel-cell operation indicates that the transport process in both chloride and fluoride electrolytes is dominated by the source ions, protons, and oxygen ions. These new materials have significant importance for both fundamental and applied research.

  • 122547.
    Zhu, Bin
    KTH, Tidigare Institutioner                               , Kemiteknik.
    Proton and oxygen ion-mixed-conducting ceramic composites and fuel cells2001Ingår i: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 145, nr 04-jan, s. 371-380Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This work focuses on the behaviour and role of protons and oxygen ions for the electrical properties of salt-oxide composites based on halides, more specifically on fluorides e.g. MFx (M = Li, Na. Ca, Ba, Sr, Mg. x = 1, 2)-based composites with oxides. The electrical properties were studied by using DC measurements, employing either gas concentration cell or fuel cell techniques. The conductivity of the fluoride-based composite electrolytes is 10(-3)-10(-2) S/cm at temperatures between 600 and 800 degreesC. Proton and oxygen ion defects, their generation and transport, showed a very strong dependence on the employed gas resources. Possessing both proton and oxygen ion conduction, on one hand, enhances the material total conductivity and, on the other hand, may promote the electrode reaction and the kinetics at two interfaces between the electrolyte and electrodes for fuel cells, thus, enhancing the cur-rent exchange rate and fuel cell performance. Using these composite electrolytes, a typical power density of 120-160 mW/cm(2) under a current density 300-800 mA/cm(2) was obtained in a fuel cell. Although both proton and oxygen ion conduction are possible, the proton defect concentration and related conduction generally predominate as the basic feature of the halide-based composite materials.

  • 122548.
    Zhu, Bin
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Solid oxide fuel cell (SOFC) technical challenges and solutions from nano-aspects2009Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 33, nr 13, s. 1126-1137Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The classical (over 100 years) oxygen ion conductor and theory for solid oxide fuel cells (SOFCs) have met critical challenges, which are caused by the electrolyte material, the heart of the SOFC. Ionic conductivity of 0.1 S cm(-1) as a basic requirement limits conventional SOFC electrolyte material, yttrium stabilized zirconia (YSZ) functioning at ca. 1000 degrees C. Such high temperature prevents SOFC technology from commercialization. Design and development of materials functioning at low temperatures are therefore a critical challenge. State of the art of the nanotechnology remarks a great potential for SOFCs. Through a review of typical SOFC electrolyte materials and analysis of the ionic conduction theory as well as constrains and disadvantages in single-phase materials, the need for design, development and theory of new materials are obvious. Our approach is to design and develop two-phase materials and functionalities at interfaces between the constituent phases in nanotech-based composites, that is nanocomposites. The nano- and composite technologies can realize superionic conduction by constructing the interfaces as 'ion highways'. Manipulation of the interphases of the nanocomposites can overcome SOFC challenges and thus enhance and improve material conductivity and FC performance at significantly lower temperatures (300-600 degrees C).

  • 122549.
    Zhu, Bin
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik.
    Albinsson, I.
    Andersson, C.
    Borsand, K.
    Nilsson, M.
    Mellander, B. E.
    Electrolysis studies based on ceria-based composites2006Ingår i: Electrochemistry communications, ISSN 1388-2481, E-ISSN 1873-1902, Vol. 8, nr 3, s. 495-498Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Electrolysis behaviors have been investigated based on ceria-based composite electrolytes and fuel cells. The results showed that both proton and oxygen ion conduction exist in the ceria-based composite electrolytes resulting in high current outputs in both fuel cell and electrolysis operations. Corresponding to high current output in the electrolysis cell, a high hydrogen production can be expected. This work has first demonstrated the ceria-based composite electrolyte used for electrolysis process.

  • 122550.
    Zhu, Bin
    et al.
    KTH, Tidigare Institutioner                               , Kemiteknik.
    Albinsson, I.
    Mellander, B. E.
    Intermediate temperature fuel cells using alkaline and alkaline earth fluoride-based electrolytes2000Ingår i: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 135, nr 04-jan, s. 503-512Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Investigation of fuel cell applications using fluoride electrolytes, especially alkaline and alkaline earth fluorides, is a very new subject. Actually, most of the fluorides can function as fuel cell electrolytes, but the alkaline and alkaline earth fluorides are specially interesting since in composite materials they exhibit excellent performance for fuel cell electrolytes. Among the alkaline earth fluoride fuel cells, the best performance was achieved thus far for the fuel cell using the NaF-BaF2-Al2O3 electrolyte and LiNiO2 anode supported technique: it reached a power density of about 110 mW cm(-2) at a current density of 250 mA cm(-2) at 750 degreesC. Both proton and oxygen ionic conduction may exist in the alkaline earth fluorides since, during the fuel cell operation, water was observed at both the anode and the cathode, but, in most cases, water was formed at the cathode side mainly. Thus, proton conduction predominates, resulting in excellent fuel cell performances. A possible ionic transport mechanism is also discussed.

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