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  • 124251.
    Yu, Pian
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Centres, ACCESS Linnaeus Centre.
    Dimarogonas, Dimos V.
    KTH, School of Electrical Engineering and Computer Science (EECS), Centres, ACCESS Linnaeus Centre.
    Explicit computation of sampling period in periodic event-triggered multi-agent control2018In: Proceedings of the American Control Conference, Institute of Electrical and Electronics Engineers Inc. , 2018, p. 3038-3043Conference paper (Refereed)
    Abstract [en]

    This paper investigates the synchronization of nonlinear sampled-data multi-agent systems. The purpose is to obtain an explicit formula for the maximum allowable sampling period (MASP) that guarantees exponential synchronization. Two implementation scenarios are considered. We first propose an approach on finding the MASP for periodic time-triggered sampled-data control. Then, a periodic event-triggered communication and control strategy is formulated, where a communication function and a control function are designed for each agent to determine whether or not the sampled data or the control input should be transmitted at each sampling instant. It is shown that there is a tradeoff between the sampling frequency and the convergence performance. The theoretical results are illustrated in simulations.

  • 124252.
    Yu, Pian
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control.
    Dimarogonas, Dimos V.
    KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control.
    Explicit computation of sampling period in periodic event-triggered multi-agent control under limited data rate2018In: IEEE Transactions on Control of Network Systems, E-ISSN 2325-5870Article in journal (Refereed)
    Abstract [en]

    This paper investigates the coordination of nonlinear sampled-data multi-agent systems subject to data rate constraint. The purpose is to design resource-efficient communication and control strategies that guarantee exponential synchronization. Two implementation scenarios are considered, the period time-triggered control and the period event-triggered control. One of the main difficulties of the problem is to obtain an explicit formula for the maximum allowable sampling period (MASP). To this end, an approach on finding the MASP for periodic time-triggered control is proposed first. Then, an asynchronous period event-triggered control strategy is formulated, a communication function and a control function are designed for each agent to determine respectively whether or not the sampled data and the control input should be transmitted at each sampling instant. Finally, the constraint of limited data rate is considered. An observer-based encoder-decoder and a finite-level quantizer are designed respectively for the Sensor-Controller communication and the Controller-Actuator communication such that certain constraint on the data rate is satisfied. It is shown that exponential synchronization can still be achieved in the presence of data rate constraint. A simulation example is given to illustrate the effectiveness of the theoretical results

  • 124253.
    Yu, Pian
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Dimarogonas, Dimos V.
    KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control.
    Time-constrained multi-agent task scheduling based on prescribed performance control2018In: 2018 IEEE CONFERENCE ON DECISION AND CONTROL (CDC), IEEE , 2018, p. 2593-2598Conference paper (Refereed)
    Abstract [en]

    The problem of time-constrained multi-agent task scheduling and control synthesis is addressed. We assume the existence of a high level plan which consists of a sequence of cooperative tasks, each of which is associated with a deadline and several Quality-of-Service levels. By taking into account the reward and cost of satisfying each task, a novel scheduling problem is formulated and a path synthesis algorithm is proposed. Based on the obtained plan, a distributed hybrid control law is further designed for each agent. Under the condition that only a subset of the agents are aware of the high level plan, it is shown that the proposed controller guarantees the satisfaction of time constraints for each task. A simulation example is given to verify the theoretical results.

  • 124254.
    Yu, Pian
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control.
    Fischione, Carlo
    KTH, School of Electrical Engineering and Computer Science (EECS), Network and Systems Engineering.
    Dimarogonas, Dimos V.
    KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control.
    Distributed Event-Triggered Communication and Control of Linear Multiagent Systems Under Tactile Communication2018In: IEEE Transactions on Automatic Control, ISSN 0018-9286, E-ISSN 1558-2523, Vol. 63, no 11, p. 3979-3985Article in journal (Refereed)
    Abstract [en]

    This note is concerned with the consensus of linear multiagent systems under tactile communication. Motivated by the emerging tactile communication technology where extremely low latency has to be supported, a distributed event-triggered communication and control scheme is proposed for the data reduction of each agent. First, an event-triggered data reduction scheme is designed for the communication between neighbors. Under such a communication scheme, a distributed event-triggered output feedback controller is further implemented for each agent, which is updated asynchronously with the communication action. It is proven that the consensus of the underlying multiagent systems is achieved asymptotically. Furthermore, it is shown that the proposed communication and control strategy fulfils the reduction of both the frequency of communication and controller updates as well as excluding Zeno behavior. A numerical example is given to illustrate the effectiveness of the proposed control strategy.

  • 124255.
    Yu, Pian
    et al.
    KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Dimarogonas, Dimos V.
    KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Event-Triggered Output Feedback Control for Linear Systems under Tactile Communication2017In: 2017 IEEE 56th Annual Conference on Decision and Control, CDC 2017, Institute of Electrical and Electronics Engineers (IEEE), 2017, p. 5451-5456Conference paper (Refereed)
    Abstract [en]

    This paper investigates an event-triggered output feedback control strategy of linear systems under tactile communication, for which two different frameworks are considered. Motivated by the emerging tactile communications technology where latencies are very small but at the price of limited message sizes, a perception-based deadband principle is proposed for the data reduction of communication. In each framework, under an assumption that the deadband factor is upper bounded with respect to the system model, it is proven that global asymptotic stability of the closed loop system is achieved. Then, an event-triggered output feedback controller under tactile communication is further introduced. It is shown that the designed controller is capable of reducing the frequency of controller updates as well as excluding Zeno behavior. Numerical examples are given to illustrate the effectiveness of the proposed control algorithm.

  • 124256.
    Yu, Q. Z.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Brage, Claes O.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Chen, G. X.
    Sjöström, Krister
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    The fate of fuel-nitrogen during gasification of biomass in a pressurised fluidised bed gasifier2007In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 86, no 4, p. 611-618Article in journal (Refereed)
    Abstract [en]

    The distribution of fuel-nitrogen in gases, tar and char from gasification of biomass in a pressurised fluidised bed gasifier was investigated. Four species of biomass: birch, Salix, Miscanthus and Reed canary grass were gasified at 0.4 MPa and 900 degrees C. Oxygen-enriched nitrogen was used as fluidising agent. As a reference, gasification of Daw Mill coal was also carried out under the same experimental conditions. The experimental results illustrate that both the nature of the original fuels and the chemical structure of the nitrogen in the fuel have influence on the distribution of fuel-nitrogen in gases (NH3, HCN, NO), tar and char under the employed experimental conditions. The present work also shows that the types of nitrogen heterocyclic compounds (NHCs) in the tar from different kinds of biomass are the same and the major compound is pyridine. However, the distribution of the various NHCs in the tar from the four species of biomass varies: the higher the content of fuel-nitrogen, the higher the concentration of two-ring NHCs in the tar. An effective method for extracting NHCs from the acidic absorption of the product gas was introduced in the present work. The method makes use of solid phase extraction (SPE) by a silica-based C-18 tube to extract the NHCs which subsequently were analysed by gas chromatography (GC) with flame ionisation detection (FID). The recovery and reproducibility of the SPE technique for NHCs is discussed.

  • 124257.
    Yu, Q. Z.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Brage, Claes O.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Nordgreen, Thomas
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Sjöström, Krister
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Effects of Chinese dolomites on tar cracking in gasification of birch2009In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 88, no 10, p. 1922-1926Article in journal (Refereed)
    Abstract [en]

    To minimize tar in the producer gas from birch gasification at 700, 750 and 800 degrees C, four Chinese dolomites (Zhenjiang, Nanjing, Shanxi, Anhui) and a Swedish dolomite (Sala) used as reference were studied in a laboratory-scale atmospheric fluidized bed gasifier. The gasifier was equipped with a downstream fixed catalyst bed. The results imply that all dolomites but Anhui dolomite effectively decompose tar into gases. Anhui dolomite showed a low catalytic capacity to crack tar produced at 700 and 800 degrees C. The influence of various ratios of steam to biomass on tar content in the producer gas after passing over dolomite was studied. The tar cracking efficiency of the dolomites did not improve significantly with the ratio of steam to biomass in the region 0.11-0.52.

  • 124258. Yu, Qing C.
    et al.
    Hirst, Claire E.
    Costa, Magdaline
    Ng, Elizabeth S.
    Schiesser, Jacqueline V.
    Gertow, Karin
    KTH, School of Biotechnology (BIO).
    Stanley, Edouard G.
    Elefanty, Andrew G.
    APELIN promotes hematopoiesis from human embryonic stem cells2012In: Blood, ISSN 0006-4971, E-ISSN 1528-0020, Vol. 119, no 26, p. 6243-6254Article in journal (Refereed)
    Abstract [en]

    Transcriptional profiling of differentiating human embryonic stem cells (hESCs) revealed that MIXL1-positive mesodermal precursors were enriched for transcripts encoding the G-protein-coupled APELIN receptor (APLNR). APLNR-positive cells, identified by binding of the fluoresceinated peptide ligand, APELIN (APLN), or an anti-APLNR mAb, were found in both posterior mesoderm and anterior mesendoderm populations and were enriched in hemangioblast colony-forming cells (Bl-CFC). The addition of APLN peptide to the media enhanced the growth of embryoid bodies (EBs), increased the expression of hematoendothelial genes in differentiating hESCs, and increased the frequency of Bl-CFCs by up to 10-fold. Furthermore, APLN peptide also synergized with VEGF to promote the growth of hESC-derived endothelial cells. These studies identified APLN as a novel growth factor for hESC-derived hematopoietic and endothelial cells.

  • 124259. Yu, R. X.
    et al.
    Bai, Xue-Song
    Vressner, Andreas
    Hultqvist, Anders
    Lunds Tekniska Högskola, Sweden.
    Johansson, Bengt
    Olofsson, Jimmy
    Seyfried, Hans
    Sjöholm, J.
    Richter, Mattias
    Aldén, Marcus
    Effect of Turbulence on HCCI Combustion2007In: Session: Homogeneous Charge Compression Ignition (HCCI) (Part 4 of 8) Combustion Modeling / Optical Diagnostics, 2007Conference paper (Refereed)
    Abstract [en]

    This paper presents large eddy simulation (LES) and experimental studies of the combustion process of ethanol/air mixture in an experimental optical HCCI engine. The fuel is injected to the intake port manifolds to generate uniform fuel/air mixture in the cylinder. Two different piston shapes, one with a flat disc and one with a square bowl, were employed to generate different in-cylinder turbulence and temperature field prior to auto-ignition. The aim of this study was to scrutinize the effect of in-cylinder turbulence on the temperature field and on the combustion process. The fuel tracer, acetone, is measured using laser induced fluorescence (LIF) to characterize the reaction fronts, and chemiluminescence images were recorded using a high speed camera, with a 0.25 crank angle degree resolution, to further illustrate the combustion process. Pressure in the cylinder is recorded in the experiments. Spatial and temporal resolved LES was used to gain information on the turbulence mixing, heat transfer and combustion process. It was shown that gas temperature in the piston bowl is generally higher than that in the squish, leading to an earlier ignition in the bowl. Compared to the disc engine, the square bowl engine has a higher temperature inhomogeneity owing to the turbulence wall heat transfer. The experimentally observed higher combustion duration and slower pressure rise rate in the square bowl engine as compared to the disc engine can be explained by the higher temperature inhomogeneity in the square bowl engine.

  • 124260.
    Yu, Shengze
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Engineering.
    Exploitation of interactions with the neonatal Fc receptor to manipulate biological half-lives for therapeutic applications2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Protein engineering provides powerful tools to create useful proteins with desired properties. In this thesis, rational design principles have been used for development of fusion proteins that can interact with the neonatal Fc receptor (FcRn) for potential medical applications. 

    FcRn is widely expressed in the human body. The natural ligands of FcRn are immunoglobulin G (IgG) and serum albumin (SA). FcRn can bind to both proteins in a pH dependent manner and endow them with an unusually long half-life in vivo. Protein building blocks interacting directly or indirectly with FcRn may potentially be used to either piggy-back on the FcRn-system for extension of the in vivo half-life or to saturate the system to decrease the in vivo half-life of the natural ligands. In this thesis, I have explored an FcRn binding affibody molecule (ZFcRn) and/or an albumin binding domain (ABD) for these purposes. 

    In study I and II, the prolactin receptor was found to often be expressed in glioblastoma multiforme tumors from patients as well as in glioblastoma multiforme cells lines. We investigated a novel antagonist of the prolactin receptor in vitro and found that it could block signaling through the receptor as well as cellular invasiveness. An antagonist of prolactin receptor could thus potentially become a drug for treatment of glioblastoma multiforme. However, the antagonist will likely have a short plasma half-life due to its small molecular size, which limits its usability. Therefore, it was expressed as a fusion to ABD, which interacts indirectly with FcRn. The produced fusion protein was found to be able to block signaling through the prolactin receptor in vitro and also had a prolonged plasma half-life in vivo

    The goal of study III was to investigate the properties of human growth hormone (hGH) when it was expressed as a protein fusion with ZFcRn, interacting directly with FcRn, and/or ABD. The fusion proteins, ZFcRn-hGH, ABD-hGH, and ZFcRn-ABD-hGH could be recombinantly expressed and successfully purified to homogeneity. They had the expected binding abilities to FcRn, SA and hGH receptor. They were all found to be able to induce signaling over the plasma membrane in a model cell line. 

    Patients suffering from many autoimmune diseases produce particular IgG molecules, which are responsible for the disease symptoms. A potential treatment could be to increase the catabolism of these IgGs to relieve disease symptoms. In study IV, an FcRn interacting affibody molecule was investigated for IgG depletion by blocking the IgG/FcRn interaction. In vitro, we first found that the affibody molecule shares a common binding site with IgG on FcRn, which indicates that the affibody should be able to block IgG from binding to FcRn. In vivo, we injected large amounts of the affibody molecules in different formats in mice and found up to 39% reduction of total endogenous IgG. In a clinical setting, reduction of total IgG level would also reduce the disease causing IgGs, and potentially ameliorate the symptoms of IgG-driven autoimmune diseases. 

    Taken together, I have in this thesis explored application of FcRn interacting molecules for extension of biological half-lives of therapeutically relevant proteins and reduction of total IgG level by FcRn blocking. 

  • 124261.
    Yu, Shengze
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science.
    Alkharusi, Amira
    Sultan Qaboos Univ, Coll Med & Hlth Sci, Muscat, Oman..
    Norstedt, Gunnar
    Sultan Qaboos Univ, Coll Med & Hlth Sci, Muscat, Oman.;Karolinska Inst, Ctr Mol Med, Stockholm, Sweden..
    Gräslund, Torbjörn
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science.
    An in vivo half-life extended prolactin receptor antagonist can prevent STAT5 phosphorylation2019In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 14, no 5, article id e0215831Article in journal (Refereed)
    Abstract [en]

    Increasing evidence suggests that signaling through the prolactin/prolactin receptor axis is important for stimulation the growth of many cancers including glioblastoma multiforme, breast and ovarian carcinoma. Efficient inhibitors of signaling have previously been developed but their applicability as cancer drugs is limited by the short in vivo half-life. In this study, we show that a fusion protein, consisting of the prolactin receptor antagonist PrlRA and an albumin binding domain for half-life extension can be expressed as inclusion bodies in Escherichia coli and efficiently refolded and purified to homogeneity. The fusion protein was found to have strong affinity for the two intended targets: the prolactin receptor (K-D = 2.3 +/- 0.2 nM) and mouse serum albumin (K-D = 0.38 +/- 0.01 nM). Further investigation showed that it could efficiently prevent prolactin mediated phosphorylation of STAT5 at 100 nM concentration and above, similar to the PrlRA itself, suggesting a potential as drug for cancer therapy in the future. Complexion with HSA weakened the affinity for the receptor to 21 +/- 3 nM, however the ability to prevent phosphorylation of STAT5 was still prominent. Injection into rats showed a 100-fold higher concentration in blood after 24 h compared to PrlRA itself.

  • 124262.
    Yu, Shengze
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Engineering.
    Gräslund, Torbjörn
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Engineering.
    Human growth hormone can transduce signals to phosphorylate STAT5 as a fusion with an affibody molecule binding the neonatal Fc receptor and an albumin binding domainManuscript (preprint) (Other academic)
    Abstract [en]

    Growth hormone replacement therapy has been used to treat children and adults with

    growth hormone deficiency for more than three decades. Growth hormone has a short

    biological half-life, requiring daily subcutaneous injections, and long acting versions are

    therefore desirable. In this study we have analyzed three fusion proteins, ZFcRn-hGH,

    ABD-hGH and ZFcRn-ABD-hGH, consisting of the human growth hormone (hGH) and an

    affibody molecule binding the neonatal Fc receptor (ZFcRn) and/or an albumin binding

    domain (ABD). Both ZFcRn and the ABD may have the ability to endow hGH with an

    extended plasma half-life. The fusion proteins could be recombinantly expressed in the

    periplasmic space of Escherichia coli and easily purified to homogeneity. All three fusion

    proteins appeared to have a strong interaction with the growth hormone receptor. ABDhGH

    and ZFcRn-ABD-hGH had a strong affinity for HSA (KD 0.006 and 0.02 nM,

    respectively). ZFcRn-hGH and ZFcRn-ABD-hGH had moderately strong affinity for mouse

    neonatal Fc receptor at pH 6.0 (KD 200 and 100 nM, respectively). The fusion proteins

    thus retained the expected binding abilities of the individual domains. Further

    characterization showed that the fusion proteins could induce phosphorylation of signal

    transducer and activator of transcription 5 (STAT5) in the model cell line U251-MG,

    further showing that the hGH-part of the fusion proteins was functional.

  • 124263. Yu, Shujun
    et al.
    Wang, Xiangxue
    Ai, Yuejie
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. North China Electric Power University, China.
    Liang, Yu
    Ji, Yongfei
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Li, Jiaxing
    Hayat, Tasawar
    Alsaedi, Ahmed
    Wang, Xiangke
    Spectroscopic and theoretical studies on the counterion effect of Cu(II) ion and graphene oxide interaction with titanium dioxide2016In: ENVIRONMENTAL SCIENCE-NANO, ISSN 2051-8153, Vol. 3, no 6, p. 1361-1368Article in journal (Refereed)
    Abstract [en]

    With the widespread use of graphene oxide (GO), it is inevitable that part of GO is released into the environment and co-exist with heavy metal ions as contaminants and is likely to be co-adsorbed on minerals and oxides. This study, for the first time, demonstrates the individual and mutual removal mechanism of GO and Cu(II) on titanium dioxide (TiO2) by batch experiments, spectroscopic analysis and density functional theory (DFT) computations. Electrostatic interaction and hydrogen bonding are the dominant modes of GO sorption onto TiO2, and the interaction of Cu(II) with TiO2 is mainly dominated by inner-sphere surface complexation. The presence of Cu(II) enhances GO coagulation on TiO2 and vice versa. The experimental results are further verified by DFT sorption energy (Es) calculations in the order (TiO2-GO)-Cu > TiO2-GO for GO interaction and (TiO2-GO)-Cu > TiO2-Cu for Cu(II) interaction. The mutual interaction is favorable for the simultaneous removal of GO and heavy metal ions by surface complexation between Cu(II) and oxygen-containing functional groups. These findings might facilitate better understanding of the co-removal behavior of carbon nanomaterials and heavy metal ions on oxides, which is crucial to decreasing the environmental toxicity of pollutants in the natural environment.

  • 124264. Yu, Shujun
    et al.
    Wang, Xiangxue
    Yao, Wen
    Wang, Jian
    Ji, Yongfei
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Ai, Yuejie
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Alsaedi, Ahmed
    Hayat, Tasawar
    Wang, Xiangke
    Macroscopic, Spectroscopic, and Theoretical Investigation for the Interaction of Phenol and Naphthol on Reduced Graphene Oxide2017In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 51, no 6, p. 3278-3286Article in journal (Refereed)
    Abstract [en]

    Interaction of phenol and naphthol with reduced graphene oxide (rGO), and their competitive behavior on rGO were examined by batch experiments, spectroscopic analysis and theoretical calculations. The batch sorption showed that the removal percentage of phenol or naphthol on rGO in bisolute systems was significantly lower than those of phenol or naphthol in single-solute systems. However, the overall sorption capacity of rGO in bisolute system was higher than single-solute system, indicating that the rGO was a very suitable material for the simultaneous elimination of organic pollutants from aqueous solutions. The interaction mechanism was mainly pi-pi interactions and hydrogen bonds, which was evidenced by FTIR, Raman and theoretical calculation. FTIR and Raman showed that a blue shift of C=C and -OH stretching modes and the enhanced intensity ratios of I-D/I-G after phenols sorption. The theoretical calculation indicated that the total hydrogen bond numbers, diffusion constant and solvent accessible surface area of naphthol were higher than those of phenol, indicating higher sorption affinity of rGO for naphthol as compared to phenol. These findings were valuable for elucidating the interaction mechanisms between phenols and graphene-based materials, and provided an essential start in simultaneous removal of organics from wastewater.

  • 124265.
    Yu, Shun
    KTH, School of Information and Communication Technology (ICT), Material Physics (Closed 20120101), Material Physics, MF (Closed 20120101).
    Molecular Interaction of Thin Film Photosensitive Organic Dyes on TiO2 Surfaces2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The photosensitive molecule adsorption on titanium dioxide (TiO2) forms the so-called “dye sensitized TiO2” system, a typical organic/oxide heterojunction, which is of great interest in catalysis and energy applications, e.g. dye-sensitized solar cell (DSSC). Traditionally, the transition metal complex dyes are the focus of the study. However, as the fast development of the organic semiconductors and invention of new pure organic dyes, it is necessary to expand the research horizon to cover these molecules and concrete the fundamental understanding of their basic properties, especially during sensitization.In this work, we focus on two different photosensitive molecules: phthalocyanines and triphenylamine-based dyes. Phthalocyanines are organic semiconductors with symmetric macro aromatic molecular structures. They possess good photoelectrical properties and good thermal and chemical stability, which make them widely used in the organic electronic industries. Triphenylamine-based dyes are new types of pure organic dyes which deliver high efficiency and reduce the cost of DSSC. They can be nominated as one of the strong candidates to substitute the ruthenium complex dyes in DSSC. The researches were carried out using classic surface science techniques on single crystal substrates and under ultrahigh vacuum condition. The photosensitive molecules were deposited by organic molecular beam deposition. The substrate reconstruction and ordering were checked by low energy electron diffraction. The molecular electronic, geometric structures and charge transfer properties were characterized by photoelectron spectroscopy, near edge X-ray absorption fine structure spectroscopy and resonant photoelectron spectroscopy (RPES). Scanning tunneling microscopy is used to directly image the molecular adsorption.For phthalocyanines, we select MgPc, ZnPc, FePc and TiOPc, which showed a general charge transfer from molecule to the substrate when adsorbed on rutile TiO2(110) surface with 1×1 and 1×2 reconstructions. This charge transfer can be prevented by modifying the TiO2 surface with pyridine derivatives (4-tert-butyl pyridine (4TBP), 2,2’-bipyridine and 4,4’-bipyridine), and furthermore the energy level alignment at the interface is modified by the surface dipole established by the pyridine molecules. Annealing also plays an important role to control the molecular structure and change the electronic structure together with the charge transfer properties, shown by TiOPc film. Special discussions were done for 4TBP for its ability to shift the substrate band bending by healing the oxygen vacancies, which makes it an important additive in the DSSC electrolyte. For the triphenylamine-based dye (TPAC), the systematic deposition enables the characterization of the coverage dependent changes of molecular electronic and geometric structures. The light polarization dependent charge transfer was revealed by RPES. Furthermore, the iodine doped TPAC on TiO2 were investigated to mimic the electrolyte/dye/TiO2 interface in the real DSSC.The whole work of this thesis aims to provide fundamental understanding of the interaction between photosensitive molecules on TiO2 surfaces at molecular level in the monolayer region, e.g. the formation of interfacial states and the coverage dependent atomic and electronic structures, etc. We explored the potential of the application of new dyes and modified of the existing system by identifying their advantage and disadvantage. The results may benefit the fields of dye syntheses, catalysis researches and designs of organic photovoltaic devices.

  • 124266.
    Yu, Shun
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Material Physics, MF.
    Ahmadi, Sareh
    KTH, School of Information and Communication Technology (ICT), Material Physics, Material Physics, MF.
    Palmgren, Pal
    Hennies, Franz
    Zuleta, Marcelo
    Göthelid, Mats
    KTH, School of Information and Communication Technology (ICT), Material Physics, Material Physics, MF.
    Modification of Charge Transfer and Energy Level Alignment at Organic/TiO2 Interfaces2009In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 113, no 31, p. 13765-13771Article in journal (Refereed)
    Abstract [en]

    Adsorption of titanyl phthalocyanine (TiOPc) on rutile TiO2(110) modified by a set of pyridine derivatives (2,2'-bipyridine, 4,4'-bipyridine, and 4-tert-butyl pyridine) has been investigated using synchrotron radiation based X-ray photoelectron spectroscopy (XPS). For the unmodified TiOPc/TiO2 system, a strong charge transfer is observed from the first layer TiOPc into the substrate, which leads to a molecular layer at the interface with a depleted highest occupied molecular orbital (HOMO). However, precovering the TiO2 surface with a saturated pyridine monolayer effectively reduce this process and leave the TiOPc in a less perturbed molecular state. Furthermore, the TiOPc HOMO and core levels are observed at different binding energies ranging by 0.3 eV on the three pyridine monolayers, which is ascribed to differences in surface potentials set up by the different pyridine/TiO2 systems.

  • 124267.
    Yu, Shun
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Material Physics, MF.
    Ahmadi, Sareh
    KTH, School of Information and Communication Technology (ICT), Material Physics, Material Physics, MF.
    Palmgren, Pål
    Lund University.
    Hennies, Franz
    KTH, School of Information and Communication Technology (ICT), Material Physics, Material Physics, MF.
    Zuleta, Marcelo
    Göthelid, Mats
    KTH, School of Information and Communication Technology (ICT), Material Physics, Material Physics, MF.
    Adsorption of TiOPc on 1×1 and 1×2 reconstructed Rutile TiO2(110) SurfacesManuscript (preprint) (Other academic)
    Abstract [en]

    Ultrathin titanyl phthalocyanine (TiOPc) layers have been studied on rutile TiO2 (110) 1×1 and 1×2 surfaces by synchrotron radiation based photoelectron spectroscopy (PES) and scanning tunneling microscopy (STM). The adsorption mode of TiOPc on the surface is of great interest in that it is strongly related to the efficiency of the charge transfer process between dye and surface. Core level spectra show that two different adsorption states coexist on both surfaces; an interfacial state that has strong interaction with the substrate while the other retains its molecular characteristics. The bonding for the interfacial state is suggested to be mainly in the 1×1 areas. Annealing significantly changes the distribution of molecules with a preferential adsorption along steps and (1x2) strands.

  • 124268.
    Yu, Shun
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics.
    Ahmadi, Sareh
    KTH, School of Information and Communication Technology (ICT), Material Physics.
    Sun, Chenghua
    KTH, School of Information and Communication Technology (ICT), Material Physics.
    Palmgren, Pal
    Hennies, Franz
    Zuleta, Marcelo
    Göthelid, Mats
    KTH, School of Information and Communication Technology (ICT), Material Physics, Material Physics, MF.
    4-tert-Butyl Pyridine Bond Site and Band Bending on TiO2(110)2010In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 114, no 5, p. 2315-2320Article in journal (Refereed)
    Abstract [en]

    In the present work, we study the bonding of 4-tert-butyl pyridine (4TBP) to the TiO2(110) surface using photoelectron spectroscopy (PES) and density functional theory (DFT) calculations. The results show that at low coverage, 4TBP adsorbs preferentially on oxygen vacancies. The calculated adsorption energy at the vacancies is 120 kJ/mol larger than that oil the five-fold-coordinated Ti4+ sites located in the rows on the TiO2 surface. The vacancy is "healed" by 4TBP, and the related gap state is strongly reduced through charge transfer into empty pi* orbitals on the pyridine ring. This leads to a change in surface band bending by 0.2 eV toward lower binding energies. The band bending does not change with further 4TBP deposition when saturating the surface to monolayer coverage, where the TiO2 surface is effectively protected against further adsorption by the dense 4TBP layer.

  • 124269.
    Yu, Shun
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Material Physics, MF.
    Ahmadi, Sareh
    KTH, School of Information and Communication Technology (ICT), Material Physics, Material Physics, MF.
    Sun, Chenghua
    KTH, School of Information and Communication Technology (ICT), Material Physics, Material Physics, MF.
    Schulte, Karina
    Pietzsch, Annette
    Hennies, Franz
    Zuleta, Marcelo
    Göthelid, Mats
    KTH, School of Information and Communication Technology (ICT), Material Physics, Material Physics, MF.
    Crystallization-Induced Charge-Transfer Change in TiOPc Thin Films Revealed by Resonant Photoemission Spectroscopy2011In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 115, no 30, p. 14969-14977Article in journal (Refereed)
    Abstract [en]

    Organic semiconductors usually demonstrate crystal structure dependent electronic properties, and through precise control of film structure, the performance of novel organic electronic devices can be greatly improved. Understanding the crystal structure dependent charge-transfer mechanism thus becomes critical. In this work, we have prepared amorphous titanyl phthalocyanine films by vacuum molecular beam evaporation and have further crystallized them through vacuum annealing. In the crystalline phase, an excited electron is rapidly transferred into neighboring molecules; while in the amorphous phase, it is mainly localized and recombines with the core hole as revealed by resonant photoemission spectroscopy (RPES). The fast electron transfer time is determined to be around 16 fs in the crystalline film, which is in good agreement with the charge-transfer hopping time estimated from the best device performance reported. The crystallized film shows more p-type characteristics than the amorphous with all the energy levels shifting toward the vacuum level. However, the greatly improved charge transfer is assigned to the molecular orbital coupling rather than this shift. From density functional theory and RPES, we specify the contribution of two differently coordinated nitrogen atoms (N2c and N3c) to the experimental results and illustrate that the N3c related orbital has experienced a dramatic change, which is keenly related to the improved charge transfer.

  • 124270.
    Yu, Shun
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Ahmadi, Sareh
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Sun, Chenghua
    The University of Queensland.
    Tabib Zadeh Adibi, Pooya
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Chow, Winnie
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Pietzsch, Annette
    Lund University.
    Göthelid, Mats
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Inhomogeneous charge transfer within monolayer zinc phthalocyanine absorbed on TiO2(110)2012In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 136, no 15, p. 154703-Article in journal (Refereed)
    Abstract [en]

    The d-orbital contribution from the transition metal centers of phthalocyanine brings difficulties to understand the role of the organic ligands and their molecular frontier orbitals when it adsorbs on oxide surfaces. Here we use zinc phthalocyanine (ZnPc)/TiO2(110) as a model system where the zinc d-orbitals are located deep below the organic orbitals leaving room for a detailed study of the interaction between the organic ligand and the substrate. A charge depletion from the highest occupied molecular orbital is observed, and a consequent shift of N1s and C1s to higher binding energy in photoelectron spectroscopy (PES). A detailed comparison of peak shifts in PES and near-edge X-ray absorption fine structure spectroscopy illustrates a slightly uneven charge distribution within the molecular plane and an inhomogeneous charge transfer screening between the center and periphery of the organic ligand: faster in the periphery and slower at the center, which is different from other metal phthalocyanine, e. g., FePc/TiO2. Our results indicate that the metal center can substantially influence the electronic properties of the organic ligand at the interface by introducing an additional charge transfer channel to the inner molecular part.

  • 124271.
    Yu, Shun
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Material Physics, MF.
    Ahmadi, Sareh
    KTH, School of Information and Communication Technology (ICT), Material Physics, Material Physics, MF.
    Zuleta, Marcelo
    Tian, Haining
    Schulte, Karina
    Pietzsch, Annette
    Hennies, Franz
    Weissenrieder, Jonas
    KTH, School of Information and Communication Technology (ICT), Material Physics, Material Physics, MF.
    Yang, Xichuan
    Göthelid, Mats
    KTH, School of Information and Communication Technology (ICT), Material Physics, Material Physics, MF.
    Adsorption geometry, molecular interaction, and charge transfer of triphenylamine-based dye on rutile TiO2(110)2010In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 133, no 22, p. 224704-Article in journal (Refereed)
    Abstract [en]

    The fast development of new organic sensitizers leads to the need for a better understanding of the complexity and significance of their adsorption processes on TiO2 surfaces. We have investigated a prototype of the triphenylamine-cyanoacrylic acid (donor-acceptor) on rutile TiO2 (110) surface with special attention on the monolayer region. This molecule belongs to the type of dye, some of which so far has delivered the record efficiency of 10%-10.3% for pure organic sensitizers [W. Zeng, Y. Cao, Y. Bai, Y. Wang, Y. Shi, M. Zhang, F. Wang, C. Pan, and P. Wang, Chem. Mater. 22, 1915 (2010)]. The molecular configuration of this dye on the TiO2 surface was found to vary with coverage and adopt gradually an upright geometry, as determined from near edge x-ray absorption fine structure spectroscopy. Due to the molecular interaction within the increasingly dense packed layer, the molecular electronic structure changes systematically: all energy levels shift to higher binding energies, as shown by photoelectron spectroscopy. Furthermore, the investigation of charge delocalization within the molecule was carried out by means of resonant photoelectron spectroscopy. A fast delocalization (similar to 1.8 fs) occurs at the donor part while a competing process between delocalization and localization takes place at the acceptor part. This depicts the "push-pull" concept in donor-acceptor molecular system in time scale. (C) 2010 American Institute of Physics. [doi:10.1063/1.3509389]

  • 124272.
    Yu, Shun
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Chen, Fei
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Wu, Qiong
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Roth, Stephan V.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. Deutsches Elektronen-Synchrotron (DESY), Germany.
    Bruning, Karsten
    Schneider, Konrad
    Kuktaite, Ramune
    Hedenqvist, Mikael S.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Structural Changes of Gluten/Glycerol Plastics under Dry and Moist Conditions and during Tensile Tests2016In: ACS SUSTAINABLE CHEMISTRY & ENGINEERING, ISSN 2168-0485, Vol. 4, no 6, p. 3388-3397Article in journal (Refereed)
    Abstract [en]

    The structures of wheat gluten-based materials are greatly influenced by plasticizer content, moisture content, and external mechanical loading. In this study, the effects of moisture on the structure of wheat gluten (WG) plasticized by glycerol were investigated by using in situ small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS), mechanical tensile testing, and thermal analyses. The materials were processed with additives of ammonium hydroxide/salicylic acid or urea and conditioned at 0, 50, and 100% relative humidity (RH). In general, water showed similar effects on the WG structure and mechanical properties regardless of the type of additive. It was observed that the known hexagonal close-packed (HCP) structure in WG was present mainly under moist conditions and swelled with an increase in water content. The absorbed water molecules hydrated the protein chains at 50% RH and further led to the formation of a separate water/glycerol phase at 100% RH. An interesting feature was observed by in situ SAXS during tensile deformation; both the HCP structure and other protein aggregates packed more densely in both the tensile and transverse directions. It is interpreted as follows: "randomly oriented" chains were drawn out and stretched in the tensile direction, which squeezes the self-assembled structures together, similar to "tightening a knot".

  • 124273. Yu, Shun
    et al.
    Santoro, Gonzalo
    Sarkar, Kuhu
    Dicke, Benjamin
    Wessels, Philipp
    Bommel, Sebastian
    Döhrmann, Ralph
    Perlich, Jan
    Kuhlmann, Marion
    Metwalli, Ezzeldin
    Risch, Johannes F.H.
    Schwartzkopf, Matthias
    Müller-Buschbaum, Peter
    Roth, Stephan V.
    Formation of Al Nanostructure on Alq3: An in Situ Grazing Incidence Small Angle X-Ray Scattering Study during Sputtering Deposition2013In: Journal of Physical Chemistry Letters, ISSN 1948-7185, E-ISSN 1948-7185, Vol. 4, no 18, p. 3170-3175Article in journal (Refereed)
  • 124274.
    Yu, Shun
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. Deutsches Elektronen-Synchrotron (DESY), Germany.
    Santoro, Gonzalo
    Yao, Yuan
    Babonneau, David
    Schwartzkopf, Matthias
    Zhang, Peng
    Vayalil, Sarathlal Koyiloth
    Wessels, Philipp
    Doehrmann, Ralph
    Drescher, Markus
    Mueller-Buschbaum, Peter
    Roth, Stephan V.
    Following the Island Growth in Real Time: Ag Nanocluster Layer on A1q3 Thin Film2015In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 119, no 8, p. 4406-4413Article in journal (Refereed)
    Abstract [en]

    The progress of organic electronics demands an increased participation of nanotechnology, and it has already been shown that the presence of metallic nanoparticles and/or nanostructured thin films can enhance the device performance. Nevertheless, to gain control over the device final performance, it is crucial to achieve a profound understanding of the nanostructure development and assembly. We investigate the growth kinetics of silver (Ag) on a tris(8-hydroxyquinolinato)aluminum (Alq3) thin film via sputter deposition. The increase of the average electron density of the Ag nanostructured film is observed to follow a sigmoidal shape development as a function of the deposited Ag thickness, as a consequence of dominant island-mediated growth. The nanoclustered film is percolated at around a thickness of 5.0 +/- 0.1 nm. At this film thickness the effective film density is about 50%. Moreover, our simulation results indicate that the shape of the nanoclusters changes from truncated spheres to cylinders upon surpassing the percolation threshold.

  • 124275.
    Yu, Sicong
    et al.
    KTH, School of Technology and Health (STH).
    Hamid Muhammad, Hamed
    KTH, School of Technology and Health (STH), Health Systems Engineering, Systems Safety and Management.
    Denoising of SPECT-image sinogram-data before reconstruction2014In: WMSCI 2014 - 18th World Multi-Conference on Systemics, Cybernetics and Informatics, Proceedings, 2014, Vol. 1, p. 202-206Conference paper (Refereed)
    Abstract [en]

    Nuclear medicine images have low signal-to-noise ratio (SNR) due to several physical limitations which degrade the image quality considerably. In this study, the Gaussian filter and the patch confidence Gaussian filter (PCG) were used to improve the image quality for Single Photon Emission Computed Tomography (SPECT). The new approach applies these filtering methods on the acquired 2D-projections before reconstructing the image. The new approach was evaluated on a SPECT dataset and the performance was compared with several conventional methods presented in the literature.

  • 124276.
    Yu, Sicong
    et al.
    KTH, School of Technology and Health (STH), Health Systems Engineering.
    Hamid Muhammed, Hamed
    KTH, School of Technology and Health (STH), Health Systems Engineering.
    Comparison of Pre- and Post-Reconstruction Denoising Approaches in Positron Emission Tomography2016In: THE 1ST 2016 INTERNATIONAL CONFERENCE ON BIOMEDICAL ENGINEERING (IBIOMED 2016), IEEE, 2016, p. 63-68Conference paper (Refereed)
    Abstract [en]

    In Positron Emission Tomography (PET), image quality is highly degraded by noise. Therefore, two main PETimage denoising approaches can be used: pre- and postreconstruction denoising. In the pre-reconstruction approach the PET sinogram is denoised before forwarding it to the image reconstruction algorithm. On the other hand, the reconstructed PET-image is denoised in the post-reconstruction approach. In this study, comparison of image quality of the resulting images of the pre- and post-reconstruction approaches is performed. In both types of approaches, the Gaussian filter, the Non-Local Means filter (NLM), the Block-Matching and 3D filter (BM3D), the K-Nearest Neighbors Filter (KNN) and the Patch Confidence K-Nearest Neighbors Filter (PCkNN) are utilized. These approaches are evaluated on a simulated PET-phantom dataset, a real-life physical thorax-phantom PET dataset as well as a reallife MicroPET-scan dataset of a mouse. The performance is measured using the Signal-to-Noise Ratio (SNR) in addition to the Contrast-to-Noise Ratio (CNR) in the resulting images.

  • 124277.
    Yu, Sicong
    et al.
    KTH, School of Technology and Health (STH), Health Systems Engineering, Systems Safety and Management.
    Hamid Muhammed, Hamed
    KTH, School of Technology and Health (STH), Health Systems Engineering.
    Noise Type Evaluation in Positron Emission Tomography Images2016In: THE 1ST 2016 INTERNATIONAL CONFERENCE ON BIOMEDICAL ENGINEERING (IBIOMED 2016), IEEE, 2016, p. 101-106Conference paper (Refereed)
    Abstract [en]

    In Positron Emission Tomography (PET), the coincident emission of gamma photon pairs constitutes the useful signals that should be detected and processed to reconstruct the desired PET images of the studied objects. However, along with the useful signal, noise is also generated and added to the detected signals that are sorted with respect to their line-ofresponse and arranged as a sinogram for each two-dimensional slice. In this paper, the type and properties of noise in PET sinogram data will be evaluated. Furthermore, the effect of the used linear and non-linear image denoising and reconstruction procedures on the type of noise will be analyzed. For this purpose, the Gaussian filter, the Median filter, the Patch Confidence k-Nearest Neighbor filter (PCkNN) and the Block Matching 3D filter (BM3D) were used to denoise PET image data, as well as the maximum likelihood expectation maximization algorithm (MLEM) and the Filtered Back Projection algorithm (FBP) to reconstruct the PET images.

  • 124278.
    Yu, Sicong
    et al.
    KTH, School of Technology and Health (STH), Health Systems Engineering, Systems Safety and Management.
    Hamid Muhammed, Hamed
    KTH, School of Technology and Health (STH), Health Systems Engineering, Systems Safety and Management.
    PET image improvement using the Patch Confidence K-Nearest Neighbors Filter2014Conference paper (Refereed)
    Abstract [en]

    In Positron Emission Tomography (PET), the resulted images are highly deteriorated by noise. In this study, we propose a new denoising framework using the Patch Confidence K-Nearest Neighbors Filter (PCKNN) to reduce noise in the sinogram before forwarding it to the reconstruction procedure. This method has been evaluated on a simulated PET image of a phantom, and the performance has been compared with several conventional methods in the literature. The results have shown that the PET image quality can be substantially improved in term of increased signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR

  • 124279. Yu, Tao
    et al.
    Zhou, Yongjin J.
    Wenning, Leonie
    Liu, Quanli
    Krivoruchko, Anastasia
    Siewers, Verena
    Nielsen, Jens
    KTH, School of Biotechnology (BIO), Gene Technology. KTH, Centres, Science for Life Laboratory, SciLifeLab. Chalmers University of Technology, Sweden.
    David, Florian
    Metabolic engineering of Saccharomyces cerevisiae for production of very long chain fatty acid-derived chemicals2017In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 8, article id 15587Article in journal (Refereed)
    Abstract [en]

    Production of chemicals and biofuels through microbial fermentation is an economical and sustainable alternative for traditional chemical synthesis. Here we present the construction of a Saccharomyces cerevisiae platform strain for high-level production of very-long-chain fatty acid (VLCFA)-derived chemicals. Through rewiring the native fatty acid elongation system and implementing a heterologous Mycobacteria FAS I system, we establish an increased biosynthesis of VLCFAs in S. cerevisiae. VLCFAs can be selectively modified towards the fatty alcohol docosanol (C22H46O) by expressing a specific fatty acid reductase. Expression of this enzyme is shown to impair cell growth due to consumption of VLCFA-CoAs. We therefore implement a dynamic control strategy for separating cell growth from docosanol production. We successfully establish high-level and selective docosanol production of 83.5 mg l(-1) in yeast. This approach will provide a universal strategy towards the production of similar high value chemicals in a more scalable, stable and sustainable manner.

  • 124280.
    Yu, Tianle
    KTH, School of Architecture and the Built Environment (ABE), Architecture.
    Stair as image2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 124281.
    Yu, Wei
    et al.
    Univ Toronto, Toronto, ON, Canada.;Univ Toronto, Informat Theory & Wireless Commun, Toronto, ON, Canada.;IEEE, Piscataway, NJ 08854 USA.;Canadian Academy Engn, Ottawa, ON, Canada.;IEEE Signal Proc Commun & Networking Tech Comm, Ottawa, ON, Canada..
    Jaldén, Joakim
    KTH, School of Electrical Engineering (EES), Signal Processing. IEEE Signal Proc Commun & Networking Tech Comm, Ottawa, ON, Canada.
    Perspectives in Signal Processing for Communications and Networking2018In: IEEE signal processing magazine (Print), ISSN 1053-5888, E-ISSN 1558-0792, Vol. 35, no 5, p. 188-+Article in journal (Refereed)
  • 124282.
    Yu, Wenbin
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Degradation of polyethylene pipes distributing chlorinated water: depletion of stabilizers, release of degraded products and polymer degradation2011Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis presents the study of antioxidants depletions in chlorinated media (10 ppm Cl2 - and ClO2 - aqueous media), polyethylene pipes degradations scenarios and migration of the degraded species to aqueous phase. Pressure testing on pipes and squalane testing with controlled pH aqueous media (6.8 ± 0.2) containing either Cl2 or ClO2 were used for assessing the degradation products. Though squalane test used a liquid hydrocarbon instead of real plastic, it provided reliable data with an efficient and readily way of sampling. Medium density polyethylene pipes stabilized with hindered phenol and phosphite antioxidants were pressure tested with water containing 4 ppm chlorine dioxide (ClO2) at 90 °C as internal medium. The stabilizers were rapidly consumed towards the inner pipe wall; the rate of consumption was four times greater than in chlorinated (Cl2) aqueous (4 ppm, pH = 6.8) at the same temperature. The depletion of stabilizers occurred far into the pipe wall. The subsequent polymer degradation was an immediate surface reaction. It was confirmed by differential scanning calorimetry, infrared spectroscopy and size exclusion chromatography that in the surface layer which came into contact with the oxidizing medium, the amorphous component of the polymer was heavily oxidized leaving a highly crystalline powder with many carboxylic acid chain ends in extended and once-folded chains. The depletion rate of the antioxidant exposed to ClO2 - aqueous media was also four times faster than that exposed to Cl2 - aqueous media by squalane test. The aqueous media was extracted to condense the remaining antioxidants and the degraded species from the squalane solution. The absorption spectra from infrared spectroscopy illustrated that carbonyl groups exist in degraded species from both ClO2 - and Cl2 - aqueous, and chlorine-carbon bond presented only in ClO2 - aqueous. It was proved by liquid chromatography that the peaks of oxidizing species formed in ClO2 aqueous media were more intense and they were different from the ones degraded compounds in Cl2.

     

     

     

     

  • 124283.
    Yu, Wenbin
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Deterioration of Polyethylene Exposed to Chlorinated Species in Aqueous Phases: Test Methods, Antioxidants Consumption and Polymer Degradation2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis presents a study of antioxidant depletion in water containing chlorinated species (water containing 10 ppm either Cl2 or ClO2, buffered to pH = 6.8), the degradation products in the aqueous phase, and polyethylene pipe degradation scenarios. A low molecular weight hydrocarbon analogue (squalane) was used instead of solid polyethylene as the host material for the antioxidants, and the depletion of antioxidants has been studied. The phenolic antioxidant Irganox 1010 was consumed ca. 4 times faster in water containing 10 ppm ClO2 than in water containing 10 ppm Cl2. The different degradation products in extracts from the aqueous phase identified by infrared, liquid chromatography and mass spectrometry revealed the different degradation mechanisms between ClO2 (" cleavage) and Cl2 (hydrogen substitution). The squalane test shows no energy barrier between 30 and 70 °C, and the activation energy of the antioxidant in solid PE was found to be ca. 21 kJ mol-1. A linear relationship has been established between the time to reach antioxidant depletion in the polyethylene tape samples and the time to reach depletion in samples based on squalane containing the same antioxidants. The surface oxidation and surface embrittlement of PE tape on long time exposure have been studied by IR and SEM. Pressure testing on medium density PE pipes with a controlled pH aqueous media (6.8 ± 0.2) containing 4 ppm either ClO2 or at 90 °C showed that the stabilizers were rapidly consumed towards the inner pipe wall and the rate of consumption in ClO2 was 4 times greater than in Cl2 solution. The subsequent polymer degradation was an immediate surface reaction. It was confirmed by differential scanning calorimetry, infrared spectroscopy and size exclusion chromatography that, in the surface layer which came into contact with the oxidizing medium, the amorphous component of the polymer was heavily oxidized leaving a highly crystalline powder with many carboxylic acid chain ends in extended and once-folded chains.

  • 124284.
    Yu, Wenbin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Azhdar, Bruska
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Andersson, D.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Reitberger, Torbjörn
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry (closed 20110630).
    Hassinen, J.
    Exova AB, Studsvik, Tystberga, Sweden.
    Hjertberg, T.
    Borealis AB, Stenungsund, Sweden.
    Gedde, Ulf
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Deterioration of polyethylene pipes exposed to water containing chlorine dioxide2011In: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 96, no 5, p. 790-797Article in journal (Refereed)
    Abstract [en]

    Chlorine species used as disinfectants in tap water have a deteriorating effect on many materials including polyethylene. There are only very few scientific reports on the effect on polyethylene pipes of water containing chlorine dioxide. Medium-density polyethylene pipes stabilized with hindered phenol and phosphite antioxidants were pressure tested with water containing 4 ppm chlorine dioxide at 90 degrees C and pH = 6.8 as internal medium. The stabilizers were rapidly consumed towards the inner pipe wall; the rate of consumption was four times greater than in chlorinated water (4 ppm, pH = 6.8) at the same temperature. The depletion of stabilizer occurred far into the pipe wall. A supplementary study on a polymer analogue (squalane) containing the same stabilizer package showed that the consumption of the phenolic antioxidant was 2.5 times faster when exposed water containing chlorine dioxide than on exposure to chlorinated water. The subsequent polymer degradation was an immediate surface reaction. It was confirmed by differential scanning calorimetry, infrared spectroscopy and size exclusion chromatography that in the surface layer which came into contact with the oxidising medium, the amorphous component of the polymer was heavily oxidized leaving a highly crystalline powder with many carboxylic acid chain ends in extended and once-folded chains. Scanning electron microscopy showed that propagation of cracks through the pipe wall was assisted by polymer degradation.

  • 124285.
    Yu, Wenbin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Gedde, Ulf
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Characterization of degradation products from a phenolic antioxidant in squalane exposed to chlorinated aqueous mediaIn: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321Article in journal (Other academic)
  • 124286.
    Yu, Wenbin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Gedde, Ulf
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Hjertberg, Thomas
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Reitberger, Torbjörn
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Deterioration of polyethylene exposed to water containing chlorine dioxide: Testing methods, antioxidant consumption, and polymer degradation2014In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 248Article in journal (Other academic)
  • 124287.
    Yu, Wenbin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Reitberger, Torbjörn
    KTH, School of Chemical Science and Engineering (CHE).
    Hjertberg, T.
    Oderkerk, J.
    Costa, F. R.
    Englund, V.
    Gedde, Ulf W.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Chlorine dioxide resistance of different phenolic antioxidants in polyethylene2015In: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 111, p. 1-6Article in journal (Refereed)
    Abstract [en]

    A series of polyethylene tape samples containing 8 different phenolic antioxidants (concentration = 0.1 +/- 0.01 wt.%) were exposed to water containing 10 ppm chlorine dioxide buffered to pH = 6.8 at 70 degrees C for different periods of time. The degradation rate and depletion time of the antioxidants in the polyethylene were obtained by oxidation induction time measurements using DSC. The majority of the tape samples (6 out of 8) showed a simple behaviour: the rate of antioxidant loss decreased and the antioxidant depletion time increased in linear fashion with increasing initial molar concentration of phenolic groups in the polymer. The tape that contained Hostanox O3 had a high initial phenolic concentration but it exhibited a short antioxidant depletion time due to the limited solubility of this antioxidant in polyethylene. Tapes containing Irganox 1330 and Cyanox 1790 showed antioxidant depletion times that were almost twice that of the other antioxidants with the same initial molar concentration of phenolic groups.

  • 124288.
    Yu, Wenbin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Reitberger, Torbjörn
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hjertberg, T.
    Oderkerk, J.
    Costa, F. R.
    Gedde, Ulf W.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Antioxidant consumption in squalane and polyethylene exposed to chlorinated aqueous media2012In: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 97, no 11, p. 2370-2377Article in journal (Refereed)
    Abstract [en]

    Squalane stabilized with 0.2 wt.% of Irganox 1010 and a medium-density polyethylene containing 0.1 wt.% of the same antioxidant were exposed to two different aqueous media (water solutions containing either 10 ppm Cl-2 or 10 ppm ClO2, both buffered to pH = 6.8) at different temperatures between 30 and 70 degrees C. The squalane phase was characterized by differential scanning calorimetry (oxidation induction time, OIT) and infrared spectroscopy, and the aqueous media were analysed after concentrating the analytes using liquid-liquid extraction by liquid chromatography, mass spectrometry and infrared spectroscopy. OIT measurements were carried out on the polyethylene samples after exposure to the chlorinated aqueous media. Exposure of the squalane systems to water containing ClO2 resulted in discolouration by the formation of quinoid structures and a faster depletion of the antioxidant than exposure to water containing Cl-2. The activation energy for the loss of antioxidant activity on exposure to ClO2-water was very low (<10 kJ mol(-1)) in the squalane test (no diffusion control) and 21 +/- 2 kJ mol(-1) at a depth of 1-2 mm from the surface of polyethylene plaques (diffusion control). Calculation from earlier published OIT data from a HDPE exposed to Cl-2-water yielded an activation energy for the loss antioxidant activity of 68 kJ mol(-1). The antioxidant degradation products obtained from the exposure to the ClO2 aqueous medium were found at a higher concentration, were more polar and exhibited a higher proportion of low molar mass species than those obtained after exposure to the Cl-2 aqueous medium. The important chemical difference between ClO2 and Cl-2 is that the former is a one-electron oxidant whereas the latter preferentially reacts by hydrogen substitution. Possible further reactions, in agreement with the observations made, are proposed.

  • 124289.
    Yu, Wenbin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Sedghi, Ehram
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Nawaz, Sohail
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Hjertberg, T.
    Oderkerk, J.
    Costa, F. R.
    Gedde, Ulf
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Assessing the Long-­term Performance of Polyethylene Stabilised WithPhenolic Antioxidants Exposed to Water Containing Chlorine Dioxide2013In: Polymer testing, ISSN 0142-9418, E-ISSN 1873-2348, Vol. 32, no 2, p. 359-365Article in journal (Refereed)
    Abstract [en]

    The addition of chlorine dioxide disinfectant to tap water prevents the spread of infection but has a serious drawback in that it degrades materials used in piping, including pipes made of polyethylene. Efficient methods are required to assess the long-term performance of different combinations of antioxidants and polyethylene grades. We have previously presented a screening method which exposes solutions of phenolic antioxidants in squalane (a liquid, low molar mass analogue of polyethylene) to 70 °C water containing either chlorine dioxide or chlorine. This method assesses the stability of the antioxidants towards these aqueous chlorinated media by determining the oxidation induction time through differential scanning calorimetry. The same experimental set-up with two modifications was used in developing a new method. A 0.3 mm thick polyethylene tape replaced the squalane phase and the supply of fresh water containing chlorine dioxide (10 ppm at pH = 6.8) was continuous; this required minimum attention from the operator over the longer exposure time periods used. Tapes of medium-density polyethylene containing 0.1 wt.% of six different phenolic antioxidants were studied. A linear relationship was established between the times to reach antioxidant depletion in the polyethylene tape samples and the times in the squalane samples (with the same antioxidants at the same concentration). A linear relationship was also found between the initial antioxidant consumption rates in polyethylene and squalane. Infrared spectroscopy and scanning electron microscopy of drawn samples revealed the onset of surface oxidation and surface embrittlement in tape samples exposed beyond the time for antioxidant depletion.

  • 124290.
    Yu, Wenhe
    KTH, School of Industrial Engineering and Management (ITM), Industrial Ecology.
    Approaches to energy efficiency in China’s large-scale public building2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In recent years, the energy shortage has become a barrier to social development as there is a shortage of resources, especially non-renewable resources. In order to improve the current situation of human settlement for future generations, a series of environmental protection activities and rational utilizations of natural resources have been carried out at a global level on the theme of "Sustainable Development". Along with the quantitative growth of Chinese public buildings, especially the Large-Scale Public Buildings, the levels of energy consumption are rising and this phenomenon has been seen as a key point of energy management from a national view.

    This paper discusses the realities of energy consumption and the energy-saving policies of public buildings in the world’s major developed countries, and sums up the current condition of Chinese energy consumption in relation to public buildings. With regard to these factors, this paper tries to find approaches for solving the existing problems in each construction section. Less developed construction technology in China leads to a waste of materials and labor force. There is a lack of professional personnel to handle the operational management and a lack of consideration for energy efficiency in the designing process. There is not a suitable framework for compiling statistics and data on energy consumption. There are still many management problems such as inadequate policy standards in operability or implementation, unclear positioning in governmental management, ineffective incentive or punitive mechanisms, and a defective state system which results directly in an undeveloped service system for energy efficiency. Based on all of the problems listed above, this paper suggests solutions in four areas, namely Policy, Energy Statistics, Management and Education, in order to give academic support for the overhaul of Large-Scale Public Buildings towards greater energy efficiency in China.

  • 124291.
    Yu, Wenyuan
    KTH, School of Engineering Sciences (SCI), Mechanics.
    Development of a Fully Vectorized Potential Flow Solver2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Centered finite difference is the basic method in this paper for spatial discretization. In general, except the schemes that will be used adjacent tothe boundary points, centered finite difference schemes will be used on the main mesh points. Depending on the requirement of order of accuracy and optimization, different multi-point stencil schemes will be built in Matlab in the form of matrix. As a result, solving PDEs is actually operating matrices in Matlab. Standard schemes and optimized schemeswill be tested with 1D linear convection equation before applying them to the solvers. In 2D-pulse case, the rectangular domain will be transformed into a wavy domain and as a result Jacobian transformation method will betested. Results from different schemes will be compared with the analytical solution in two dimensional pulse case.

  • 124292. Yu, X.
    et al.
    An, L.
    Yang, J.
    Tu, S. -T
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes. Mälardalen University, Sweden.
    CO2 capture using a superhydrophobic ceramic membrane contactor2015In: Journal of Membrane Science, ISSN 0376-7388, E-ISSN 1873-3123, Vol. 496, p. 1-12, article id 13949Article in journal (Refereed)
    Abstract [en]

    The wetting and fouling of a membrane contactor deteriorated performance of the membrane gas absorption system for CO<inf>2</inf> post-combustion capture in coal-fired power plants. To solve these problems, in this study, a superhydrophobic ceramic (SC) membrane contactor was fabricated from an alumina tube with a ZrO<inf>2</inf> layer by means of grafting with fluoroalkylsilane (FAS) in a triethoxy-1H,1H,2H,2H-tridecafluoro-n-octylsilane solution. The performances of the SC membrane contactor and polypropylene (PP) hollow fiber membrane contactor were compared through experiments conducted in a CO<inf>2</inf> absorption experimental system using a monoethanolamine (MEA) aqueous solution. Although the membrane fabrication cost per effective membrane area (CPA) of the SC membrane is 12.5 times that of the PP hollow fiber membrane, the SC membrane fabrication cost per absorbed CO<inf>2</inf> flux (CPC) was lower than that of the PP membrane. For the SC membrane, the detrimental effect of wetting can be alleviated by periodic drying to ensure a high CO<inf>2</inf> removal efficiency (>90%). Drying does not work for the PP membrane because the swelling of the PP fibers is irreversible. The SC membrane contactor exhibited a better anti-fouling ability than the PP membrane contactor because the superhydrophobic surface can self-clean. To ensure a continuous, high-efficiency CO<inf>2</inf> removal, a method was proposed in which two-hollow fiber SC membrane contactors operate alternately with the addition of periodic drying. The SC hollow fiber membrane contactor shows great potential in real industrial CO<inf>2</inf> post-combustion capture because of its good anti-wetting and anti-fouling features.

  • 124293. Yu, X.
    et al.
    Shum, P.
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Ren, G. B.
    Silica-based birefringent large-mode-area fiber with a nanostructure core2008In: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 20, no 1-4, p. 246-248Article in journal (Refereed)
    Abstract [en]

    Nanostructure photonic crystals with two-fold symmetry are introduced into a silica-based fiber core to induce high birefringence between the two nearly orthogonal fundamental modes. We theoretically study and provide our preliminary findings on the birefringence property of such fibers over a large wavelength range. A large-mode-area structure with a typical high birefringence in the order of 10(-1) is easily realized.

  • 124294. Yu, X.
    et al.
    Yang, J.
    Lu, H.
    Tu, S.-T.
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes. School of Business Society and Technology, Mälardalen University, Västerås, Sweden.
    Energy-efficient extraction of fuel from Chlorella vulgaris by ionic liquid combined with CO2 capture2015In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 160, p. 648-655Article in journal (Refereed)
    Abstract [en]

    Algae-sourced feedstocks remain confined to commercialization because of the high cost and energy consumption of biomass cultivation and feedstock extraction. In this study, to reduce the energy consumption required for algae extraction, experiments with Chlorella vulgais extraction by ionic liquids (ILs) combined with CO<inf>2</inf> capture were conducted considering that captured CO<inf>2</inf> by ILs can compensate the energy consumption of extraction. The results showed that the addition of CO<inf>2</inf> to [BMIM][BF<inf>4</inf>] increased the lipid yield of Chlorella vulgaris from 68.0% to 75.6%. The properties of synthesized biodiesel from C. vulgaris lipids met the UNE-EN 14214 European biodiesel standard except for oxidative stability. Protein denaturation and degradation were found during the lysis of algae cells. Approximately 82.2wt.% of the total extracted proteins could be precipitated during both algae lysis and supernatant liquid drying. A microalgae-to-biofuel route including C. vulgaris extraction and CO<inf>2</inf> capture was proposed that involves wet algae input and delivery outputs of water, biodiesel, pyrolysis oil, proteins, sugars, biogas and glycerol. Fossil energy ratios (FER) based on the overall energy balance were 3.30 (n= 1, n is the volume ratio of IL to wet algae) and 3.84 (n= 2) for [BMIM][BF<inf>4</inf>] with CO<inf>2</inf> capture, approximately 2.5 times those based on commercially available technologies. The possibilities of synthesizing novel ILs that show both high CO<inf>2</inf> absorption and good abilities in cell wall breakage are discussed. More progress is greatly needed to reduce IL recovery loss.

  • 124295. Yu, X.
    et al.
    Zhang, X.
    Niu, L.
    Yue, Y.
    Wu, Sihong
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Zhang, M.
    Dynamic evolution and driving force analysis of land use/cover change on loess plateau watershed2009In: Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering, ISSN 1002-6819, Vol. 25, no 7, p. 219-225Article in journal (Refereed)
    Abstract [en]

    Using land resources quantity change model and land use/cover change index, dynamic changes and driving forces of land use/cover change were discussed in Tianshui, Gansu Province during the resent twenty years. The results showed that slope farmland area declined sharply, terrace area increased rapidly, forestland area and orchard area increased steadily from 1986 to 2004. According to the change of land-use type transfer, the entering speed of terrace was slightly less than the exiting speed, which was in a state of equilibrium for two-way high-speed conversion, while the entering speed of shrub land was less than the exiting speed, and presented a scale reduced trend. The change degrees of the land use types in the previous period (1986-1995) was much more obvious than that in the later period (1995-2004). Besides special topography and climate factors, national policies, population growth and economic development are driving forces of land use types change. After the implementation of the natural forest protection project and returning farmland to forest projects, land use situation in the region has been improved.

  • 124296. Yu, Xia
    et al.
    Liu, Min
    Chung, Youngjoo
    Yan, Min
    Nanyang Techbological University, Singapore.
    Shum, Ping
    Coupling coefficient of two-core microstructured optical fiber2006In: Optics Communications, ISSN 0030-4018, E-ISSN 1873-0310, Vol. 260, no 1, p. 164-169Article in journal (Refereed)
  • 124297. Yu, Xia
    et al.
    Yan, Min
    Nanyang Techbological University, Singapore.
    Luo, Lian Wee
    Shum, Ping
    Theoretical investigation of highly birefringent all-solid photonic bandgap fiber with elliptical cladding rods2006In: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 18, no 11, p. 1243-1245Article in journal (Refereed)
  • 124298.
    Yu, Xia
    et al.
    Singapore Institute of Manufacturing Technology, Singapore.
    Yan, Min
    Technical University of Denmark.
    Ren, Guobin
    Tong, Weijun
    Cheng, Xueping
    Zhou, Junqiang
    Shum, Perry Ping
    Ngo, Nam Quoc
    Nanostructure core fiber with enhanced performances: Design, fabrication and devices2009In: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 27, no 11, p. 1548-1555Article in journal (Refereed)
  • 124299. Yu, Xia
    et al.
    Zhang, Ying
    Pan, Shanshan
    Shum, Ping
    Nanyang Techbological University, Singapore.
    Yan, Min
    Leviatan, Yehuda
    Li, Changming
    A selectively coated photonic crystal fiber based surface plasmon resonance sensor2010In: Journal of Optics. A, Pure and applied optics, ISSN 1464-4258, E-ISSN 1741-3567, Vol. 12, no 1Article in journal (Refereed)
  • 124300. Yu, Xianbin
    et al.
    Jia, Shi
    Pang, Xiaodan
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab). RISE ACREO AB.
    Morioka, Toshio
    Oxenloewe, Leif K.
    Beyond 100 Gbit/s wireless connectivity enabled by THz photonics2017In: Transparent Optical Networks (ICTON), 2017 19th International Conference on, IEEE Computer Society, 2017, p. 1-4Conference paper (Refereed)
    Abstract [en]

    Beyond 100Gbit/s wireless connectivity is appreciated in many scenarios, such as big data wireless cloud, ultrafast wireless download, large volume data transfer, etc. In this paper, we will present our recent achievements on beyond 100Gbit/s ultrafast terahertz (THz) wireless links enabled by THz photonics.

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