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Chinese Physics B 2012年第11期21卷 144-153页

作者： m.J.Park O.m.Kwon Ju H.Park S.m.Lee E.J.cha School of Electrical Engineering Chungbuk National University Department of Electrical Engineering Yeungnam University School of Electronic Engineering Daegu University Department of Biomedical Engineering School of MedicineChungbuk National University

We consider multi-agent systems with time-varying delays and switching interconnection topologies. By con- structing a suitable Lyapunov-Krasovskii functional and using the reciprocally convex approach, new delay-dependent consensus criteria for the systems are established in terms of linear matrix inequalities （LmIs）, which can be easily solved by using various effective optimization algorithms. Two numerical examples are given to illustrate the effectiveness of the proposed methods.

关键词： consensus multi-agent systems time delay Lyapunov method

Synchronization criteria for coupled Hopfield neural networks with time-varying delays

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Chinese Physics B 2011年第11期20卷 140-150页

This paper proposes new delay-dependent synchronization criteria for coupled Hopfield neural networks with time-varying delays. By construction of a suitable Lyapunov Krasovskii＇s functional and use of Finsler＇s lemma, novel synchronization criteria for the networks are established in terms of linear matrix inequalities （LmIs） which can be easily solved by various effective optimization algorithms. Two numerical examples are given to illustrate the effectiveness of the proposed methods.

关键词： Hopfield neural networks coupling delay synchronization Lyapunov method

H∞ synchronization of chaotic neural networks with time-varying delays

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Chinese Physics B 2013年第11期22卷 244-252页

作者： O. m. Kwon m. J. Park Ju H. Park S. m. Lee E. J. cha School of Electrical Engineering Chungbuk National University Department of Electrical Engineering Yeungnam University School of Electronic Engineering Daegu University Department of Biomedical Engineering School of Medicine Chungbuk National University

In this paper, we investigate the problem of H∞ synchronization for chaotic neural networks with time-varying delays. A new model of the networks with disturbances in both master and slave systems is presented. By constructing a suitable Lyapunov–Krasovskii functional and using a reciprocally convex approach, a novel H∞ synchronization criterion for the networks concerned is established in terms of linear matrix inequalities （LmIs） which can be easily solved by various effective optimization algorithms. Two numerical examples are given to illustrate the effectiveness of the proposed method.

关键词： chaotic neural networks time-varying delays H∞ synchronization Lyapunov method

Leader-following consensus control for networked multi-teleoperator systems with interval time-varying communication delays

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Chinese Physics B 2013年第7期22卷 96-103页

作者： m. J. Park S. m. Lee J. W. Son O. m. Kwon E. J. cha School of Electrical Engineering Chungbuk National University School of Electronic Engineering Daegu University Division of IT-Convergence Daegu Gyeongbuk Institute of Science & Technology Department of Biomedical Engineering School of MedicineChungbuk National University

We study the leader-following consensus stability and stabilization of networked multi-teleoperator systems with interval time-varying communication delays. With the construction of a suitable Lyapunov–Krasovskii functional and the utilization of the reciprocally convex approach, novel delay-dependent consensus stability and stabilization conditions for the systems are established in terms of linear matrix inequalities, which can easily be solved by various effective optimization algorithms. One illustrative example is given to illustrate the effectiveness of the proposed methods.

关键词： multi-teleoperator systems interval time-varying delay leader–following consensus problem Lyapunov method

Phase-transition-free rivets for layered oxide potassium cathodes

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Nano Research 2024年第11期17卷 9671-9678页

作者： Jie Chen Apparao m. Rao Caitian Gao Jiang Zhou Limei cha Xiaoming Yuan Bingan Lu School of Physics and Electronics Hunan University Changsha 410082 China Department of Physics and Astronomy Clemson Nanomaterials Institute Clemson University Clemson SC USA School of materials Science and Engineering Central South University Changsha 410083 China materials Science and Engineering program Guangdong Technion-Israel Institute of Technology Shantou 515063 China materials Science and Engineering program Technion-Israel Institute of Technology Haifa 32000 Israel mATEC Key Lab Guangdong Technion-Israel Institute of Technology Shantou 515063 China Hunan Key Laboratory of Nanophotonics and Devices School of Physics Central South University Changsha 410078 China

As a cathode material for potassium-ion batteries (PIBs), manganese-based layered oxides have attracted widespread attention due to their low cost, ease of synthesis, and high performance. However, the Jahn-Teller effect caused by mn3+ and the irreversible phase transformation of the structure leads to poor cycle stability, limiting the development of layered oxides in PIBs. Herein, we demonstrate the use of phase-transition-free CaTiO_(3) as rivets in K_(0.5)mn_(0.9)Ti_(0.1)O_(2) by a simple solid-state method. As verified by the in situ X-ray diffraction, the CaTiO_(3) rivets effectively prevent the slippage of the transition metal layer during charge and discharge, inhibiting structural degradation. As a result, the obtained K_(0.5)mn_(0.9)Ti_(0.1)O_(2)-0.02CaTiO_(3) shows excellent cycling stability and rate performance, with high capacities of 119.3 and 70.1 mAh·g^(-1) at 20 and 1000 mA·g^(-1), respectively. At 200 mA·g^(-1), the capacity retention remains 94.7% after more than 300 cycles. This work represents a new avenue for designing and optimizing layered cathode materials for PIBs and other batteries.

关键词： potassium cathodes layered oxide phase-transition-free perovskite rivets

A theoretical and 1-D numerical investigation on a valve/valveless air-breathing pulse detonation engine

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Chinese Journal of Aeronautics 2021年第1期34卷 68-78页

作者： Hua QIU cha XIONG Jianling LI School of Power and Energy Northwestern Polytechnical UniversityXi'an 710072China State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China

The important operating characteristics of pulsed Pressure Gain Combustion(PGC)propulsion are the pressure gain of the combustor component and the propulsive performance gain of the engine.A ramjet-type valve/valveless air-breathing pulsed detonation engine with a supersonic internal compression inlet is *** on an ideal thermal cycle,the ideal equivalent pressure ratios(pcb)of the Pulsed Detonation Combustor(PDC)are obtained theoretically which are directly related with the propulsive performance of the *** introducing an orifice loss model into the cycles,the critical pressure drop ratios through the orifice for the PDC achieving pressure gain and the engine achieving thrust gain are *** influencing factors are investigated by the use of a one-dimensional(1-D)numerical simulation *** operating characteristics of the pulse detonation engine are investigated with changes of the valve type,the inlet/outlet area ratio of the PDC,the nozzle area ratio,and flight *** these factors can affect pcbof the PDC,and pcbcan be optimized by changing the geometry of the *** most important influence parameter is the valve *** using an orifice-type aerodynamic valve,simulation results show that the PDC cannot achieve the pressure gain *** a supersonic internal compression inlet is introduced to the engine,whether the Pulse Detonation Engine(PDE)can achieve thrust gain comparable with that of an ideal Brayton cycle engine not only is related to the pressure gain of the combustor,but also needs to optimize the engine structure to reduce the total pressure loss.

关键词： Detonation Pressure gain characteristics Propulsive performance Supersonic internal compression inlet Valve/valveless Thermal cycle

Recent progress on in situ characterizations of electrochemically intercalated transition metal dichalcogenides

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Nano Research 2019年第9期12卷 2126-2139页

作者： Sajad Yazdani milad Yarali Judy J. cha Department of m.chanical Engineering and materials Science Yale UniversityNew HavenCT 06511USA Energy Sciences Institute Yale University West CampusWest HavenCT 06516USA

Layered transition metal dichalcogenides(TmDCs)have been extensively studied owing to their unique physical and chemical *** van der Waals(vdW)interact!ons betwee n the stacki ng layers of TmDCs allow intercalati on of various species including mono vale nt alkali,divale nt alkaline earth and multivale nt metal ions,zero-vale nt transiti on metals,as well as orga nic molecules,all of which can drastically alter fun dame ntal properties of the *** urge to understa nd the phe nomena and the desire to exploit them for applicati ons have inspired a great deal of investigations.A large portion of the mystery has been unveiled over the past decade of intense research;however,many questions remain open and require further *** review is concerned with investigations on structural and electronic evolution of TmDCs drive n by electrochemically con trolled in tercalati ***,we aim to survey the rece nt adva nces and experime ntal platforms for mon itoring the in tercalati on processes in situ by utilizi ng nano *** additi on,several in quiries and prospects are outlined in a broader con text for future ave nues of studies.

关键词： transition metal dichalcogenides electrochemical intercalation in situ characterizations transmission electron microscopy(TEm) magnetotransport measurements

Design and Analysis of a 0.01-to-6GHz 31dBm-P1dB 31.5%-PAE Distributed Power Amplifier in 0.25-μm GaAs Technology

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Chinese Journal of Electronics 2021年第3期30卷 549-555页

作者： mENG Fanyi LIU cha HU Jianquan mOU Shouxian mA Kaixue School of microelectronics Tianjin University School of Physics University of Electronic Science and Technology of China Smarter micro Company

This paper presents the design and analysis of a distributed power amplifier with 6-d B bandwidth from 10 mHz to 6 GHz. To meet the stringent targeted specification, the concurrent design and analysis are carefully performed with optimizations in both passive and active devices. The gate capacitive division technique is proposed and proven theoretically of bandwidth extension effect and power efficiency enhancement. To validate the theory, a prototype is designed in a 0.25-μm Ga As technology. The fabricated amplifier chip is packaged in an evaluation cavity of SmA connectors. The measurement shows an average power gain of 15 d B, OP1 d Band PSAT of 31 d Bm and 32.6 d Bm at 3 GHz, and PAE at OP1 d Band PSAT points are 31.5% and 43.7% respectively. To the best of authors’ knowledge, the amplifier achieves the highest Power-added efficiency(PAE) among the similar Ga As amplifiers.

关键词： gallium arsenide III-V semiconductors gate capacitive division technique evaluation cavity microwave amplifiers bandwidth extension effect fabricated amplifier chip power efficiency enhancement network synthesis distributed amplifiers frequency 10.0 mHz to 6.0 GHz efficiency 31.5 percent active devices network analysis average power gain passive devices SmA connectors electric connectors circuit optimisation distributed power amplifier UHF power amplifiers GaAs GaAs technology power-added efficiency GaAs amplifiers size 0.25 mum concurrent design

Improving the operational stability of perovskite solar cells with cesium-doped graphene oxide interlayer

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Journal of Energy Chemistry 2024年第9期96卷 483-490页

作者： masaud Almalki Katerina Anagnostou Konstantinos Rogdakis Felix T.Eickemeyer mostafa Othman minas m.Stylianakis Dimitris Tsikritzis Anwar Q.Alanazi Nikolaos Tzoganakis Lukas Pfeifer Rita Therisod Xiaoliang mo Christian m.Wolff Aïcha Hessler-Wyser Shaik m.Zakeeruddin Hong Zhang Emmanuel Kymakis m.chael Grätzel Laboratory of Photonics and Interfaces École Polytechnique Fédérale de Lausanne(EPFL)Lausanne 1015Switzerland Department of Electrical and Computer Engineering Hellenic Mediterranean UniversityHeraklionCrete 71410Greece Institute of Electrical and microengineering(IEm)Photovoltaics and Thin-Film Electronics Laboratory(PV-Lab) École Polytechnique Fédérale de Lausanne(EPFL)Neuchâtel 2000Switzerland Department of Nursing Faculty of Health SciencesHellenic Mediterranean UniversityCrete 71410Greece Centre Interdisciplinaire de microscopie Electronique École Polytechnique Fédérale de Lausanne(EPFL)Lausanne 1015Switzerland Future Energy Technology Institute King Abdulaziz City for Science and Technology(KACST)P.O.Box 6086Riyadh 11442Saudi Arabia State Key Laboratory of Photovoltaic Science and Technology Shanghai Frontiers Science Research Base of Intelligent Optoelectronics and PerceptionInstitute of OptoelectronicsDepartment of Materials ScienceFudan UniversityShanghai 200433China

Perovskite solar cells(PSCs)have made great advances in terms of power conversion efficiency(PCE),yet their subpar stability continues to hinder their *** interface between the perovskite layer and the charge-carrier transporting layers plays a crucial role in undermining the stability of *** this work,we propose a strategy to stabilize high-performance PSCs with PCE over 23%by introducing a cesium-doped graphene oxide(GO-Cs)as an interlayer between the perovskite and hole-transporting *** GO-Cs treated PSCs exhibit excellent operational stability with a projected T80(the time where the device PCE reduces to 80%of its initial value)of 2143 h of operation at the maximum powering point under one sun illumination.

关键词： Perovskite solar cells Doped graphene oxide Graphene related material Long-term operational stability

multi-analyte analysis of cytokines that predict outcomes in patients with hepatocellular carcinoma treated with radiotherapy

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World Journal of Gastroenterology 2017年第11期23卷 2077-2085页

作者： Hyejung cha Eun Jung Lee Jinsil Seong Department of Radiation Oncology Yonsei Cancer Center Yonsei University College of Medicine Department of Radiation Oncology Samsung Medical Center Sungkyunkwan University School of Medicine

AIm To analyze cytokine levels and to identify their association with outcome in patients with hepatocellular carcinoma(HCC) treated with radiotherapy(RT). mETHODS Patients with HCC who were treated with RT were eligible for this prospective study. Blood samples were collected before and after RT, and serum cytokine levels including interleukin(IL)-1, IL-6, IL-8, IL-10, IL-12, and tumor necrosis factor-α were analyzed. RESULTS Between 2008 and 2009, 51 patients were enrolled in this study. Baseline IL-6 level was high in patients with a history of pre-RT treatment. median survival was 13.9 mo with alpha-fetoprotein(AFP) as a significant factor(P = 0.020). median failure-free survival(FFS) for infield, outfield-intrahepatic and extrahepatic failures were 23.3, 11.5 and 12.0 mo, respectively. Sex and baseline IL-6 level were associated with infield FFS, and baseline IL-10 level was correlated with outfield-intrahepatic FFS. For extrahepatic FFS, AFP was significant(P =0.034). Patients with a baseline IL-6 level of ≥ 9.7 pg/m L showed worse infield FFS(P = 0.005), and this significance was observed only in treatment-non-na?ve patients(P = 0.022). CONCLUSION In addition to AFP, cytokines seem useful in predicting infield and outfield-intrahepatic failure. Serum cytokines could be useful biomarkers for predicting RT outcome in HCC.

关键词： Hepatocellular carcinoma Radiotherapy Cytokine Interleukin-6