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Performance Evaluation of Composite Electrolyte with GQD for All-Solid-State Lithium Batteries

Computers, Materials & Continua 2023年第1期74卷 55-66页

作者： Sung Won Hwang Dae-Ki Hong Department of System Semiconductor Engineering SangMyung UniversityCheonan-si31066Korea

The use a stabilized lithium structure as cathode material for batteries could be a fundamental alternative in the development of next-generation energy storage devices.However,the lithium structure severely limits battery life causes safety concerns due to the growth of lithium(Li)dendrites during rapid charge/discharge cycles.Solid electrolytes,which are used in highdensity energy storage devices and avoid the instability of liquid electrolytes,can be a promising alternative for next-generation batteries.Nevertheless,poor lithium ion conductivity and structural defects at room temperature have been pointed out as limitations.In this study,through the application of a low-dimensional graphene quantum dot(GQD)layer structure,stable operation characteristics were demonstrated based on Li^(+)ion conductivity and excellent electrochemical performance.Moreover,the device based on the modified graphene quantum dots(GQDs)in solid state exhibited retention properties of 95.3%for 100 cycles at 0.5 C and room temperature(RT).Transmission electronmicroscopy analysis was performed to elucidate the Li^(+)ion action mechanism in the modified GQD/electrolyte heterostructure.The low-dimensional structure of theGQD-based solid electrolyte has provided an important strategy for stably-scalable solid-state lithium battery applications at room temperature.It was demonstrated that lithiated graphene quantum dots(Li-GQDs)inhibit the growth of Li dendrites by regulating the modified Li^(+)ion flux during charge/discharge cycling at current densities of 2.2–5.5 mA cm,acting as a modified Li diffusion heterointerface.A full Li GQDbased device was fabricated to demonstrate the practicality of the modified Li structure using the Li–GQD hetero-interface.This study indicates that the low-dimensional carbon structure in Li–GQDs can be an effective approach for stabilization of solid-state Li matrix architecture.

关键词： Solid-state lithium batteries composite electrolyte quantum dot graphene

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Flexible Memristive Devices Based on Graphene Quantum-Dot Nanocomposites

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Computers, Materials & Continua 2022年第8期72卷 3283-3297页

作者： Sung Won Hwang Dae-Ki Hong Department of System Semiconductor Engineering SangMyung UniversityCheonan-si31066Korea

Artificial neural networks(ANNs)are attracting attention for their high performance in various fields,because increasing the network size improves its functioning.Since large-scale neural networks are difficult to implement on custom hardware,a two-dimensional(2D)structure is applied to an ANN in the form of a crossbar.We demonstrate a synapse crossbar device from recent research by applying a memristive system to neuromorphic chips.The system is designed using two-dimensional structures,graphene quantum dots(GQDs)and graphene oxide(GO).Raman spectrum analysis results indicate a D-band of 1421 cm^(−1) that occurs in the disorder;band is expressed as an atomic characteristic of carbon in the sp2 hybridized structure.There is also a G-band of 1518 cm^(−1) that corresponds to the graphite structure.The G bands measured for RGO-GQDs present significant GQD edge-dependent shifts with position.To avoid an abruptly-formed conduction path,effect of barrier layer on graphene/ITO interface was investigated.We confirmed the variation in the nanostructure in the RGO-GQD layers by analyzing them using HR-TEM.After applying a negative bias to the electrode,a crystalline RGO-GQD region formed,which a conductive path.Especially,a synaptic array for a neuromorphic chip with GQDs applied was demonstrated using a crossbar array.

关键词： Memristive devices neuromorphic chip resistive RAM quantum dot graphene

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A Strategy of Signal Detection for Performance Improvement in Clipping Based OFDM system

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Computers, Materials & Continua 2020年第7期64卷 181-191页

作者： Jae-Hyun Ro Won-Seok Lee Min-Goo Kang Dae-Ki Hong Hyoung-Kyu Song department of Information and Communication engineering Sejong UniversitySeoulKorea department of IT Contents Hanshin UniversityOsan-siKorea Department of System Semiconductor Engineering SangMyung UniversityCheonan-si31066Korea

In this paper,the supervised Deep Neural Network(DNN)based signal detection is analyzed for combating with nonlinear distortions efficiently and improving error performances in clipping based Orthogonal Frequency Division Multiplexing(OFDM)ssystem.One of the main disadvantages for the OFDM is the high Peak to Average Power Ratio(PAPR).The clipping is a simple method for the PAPR reduction.However,an effect of the clipping is nonlinear distortion,and estimations for transmitting symbols are difficult despite a Maximum Likelihood(ML)detection at the receiver.The DNN based online signal detection uses the offline learning model where all weights and biases at fully-connected layers are set to overcome nonlinear distortions by using training data sets.Thus,this paper introduces the required processes for the online signal detection and offline learning,and compares error performances with the ML detection in the clipping-based OFDM systems.In simulation results,the DNN based signal detection has better error performance than the conventional ML detection in multi-path fading wireless channel.The performance improvement is large as the complexity of system is increased such as huge Multiple Input Multiple Output(MIMO)system and high clipping rate.

关键词： Clipping DNN ML nonlinear distortion OFDM

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Bright hybrid white light-emitting quantum dot device with direct charge injection into quantum dot

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Chinese Physics B 2016年第12期25卷 514-519页

作者：曹进谢婧薇魏翔周洁陈超平王子兴田哲圭 Key Laboratory of Advanced Display and system Applications Ministry of EducationShanghai University School of Materials Science and engineering Shanghai University National engineering Laboratory of TFT-LCD Materials and Technologies Department of Electronic EngineeringShanghai Jiao Tong University School of Green Energy & semiconductor engineering Hoseo University

A bright white quantum dot light-emitting device （white-QLED） with 4-[4-（1-phenyl-lH-benzo[d]imidazol-2- yl）phenyl]-2- [3-（tri-phenylen-2-yl）phen-3-yl]quinazoline deposited on a thin film of mixed green/red-QDs as a bilayer emitter is fabricated. The optimized white-QLED exhibits a turn-on voltage of 3.2 V and a maximum brightness of 3660 cd/m2 @8 V with the Commission Internationale de l＇Eclairage （CIE） chromaticity in the region of white light. The ultra-thin layer of QDs is proved to be critical for the white light generation in the devices. Excitation mechanism in the white-QLEDs is investigated by the detailed analyses of electroluminescence （EL） spectral and the fluorescence lifetime of QDs. The results show that charge injection is a dominant mechanism of excitation in the white-QLED.

关键词： quantum dot light-emitting devices white ultra-thin film charge injection

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A low power V-band LC VCO with high Q varactor technique in 40 nm CMOS process

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Science China(Information Sciences) 2017年第8期60卷 252-254页

作者： Qian ZHOU Yan HAN Shifeng ZHANG Xiaoxia HAN Lu JIE Ray C.C.CHEUNG Guangtao FENG College of Information Science and Electronic engineering Zhejiang University department of Electronic engineering City University of Hong Kong semiconductor Manufacturing International Corporation

Dear editor,Demand for higher data transmission rate,particularly in the modern communication systems,has been increasing over the years.For example,the IEEE standard 802.15.3c specifies more than2 Gbps data transmission rate,which pushes the frequency band up to 60 GHz.In the transceiver,the working frequency of VCO is in 60 GHz,and that has attracted many people to study it[1,2].However,implementing high speed voltagecontrolled oscillator(VCO)through CMOS technology can be extremely challenging because of the

关键词： VCO A low power V-band LC VCO with high Q varactor technique in 40 nm CMOS process CMOS in high nm LC with

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Kernel-Based State-Space Kriging for Predictive Control

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IEEE/CAA Journal of Automatica Sinica 2023年第5期10卷 1263-1275页

作者： A.Daniel Carnerero Daniel R.Ramirez Daniel Limon Teodoro Alamo the department of system engineering and Automation University of SevilleSevilla 41020Spain the School of engineering Tokyo Institute of TechnologyTokyo 152-8552Japan department of system engineering and Automation University of SevilleSevilla 41020Spain

In this paper, we extend the state-space kriging(SSK) modeling technique presented in a previous work by the authors in order to consider non-autonomous systems. SSK is a data-driven method that computes predictions as linear combinations of past outputs. To model the nonlinear dynamics of the system, we propose the kernel-based state-space kriging(K-SSK), a new version of the SSK where kernel functions are used instead of resorting to considerations about the locality of the data. Also, a Kalman filter can be used to improve the predictions at each time step in the case of noisy measurements. A constrained tracking nonlinear model predictive control(NMPC) scheme using the black-box input-output model obtained by means of the K-SSK prediction method is proposed. Finally, a simulation example and a real experiment are provided in order to assess the performance of the proposed controller.

关键词： Data-driven methods model identification Kernel methods predictive control

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Novel orthogonal modulation format DRZ-FSK/DPSK for high-speed long-haul optical communication

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Chinese Optics Letters 2010年第9期8卷 852-855页

作者：张俊文邵宇丰方武良黄博陶理朱江波迟楠 State Key Lab of ASIC & system Department of Communication Science and Engineering Fudan University

We propose a novel advanced orthogonal modulation format dark return-to-zero frequency shift keying/differential phase shift keying （DRZ-FSK/DPSK） and its realization scheme. The DRZ-FSK/DPSK is generated by the combination of a 40-Gb/s return-to-zero （RZ） signal and a DRZ signal which is converted from the RZ using a semiconductor optical amplifier （SOA） based on nonlinear cross polarization rotation （XPR） and then re-modulated by high-bit-rate DPSK at 40 Gb/s. The feasibility of the scheme is exper-imentally demonstrated. Bit error rate （BER） results of the total 80-Gb/s DRZ-FSK/DPSK orthogonal modulation signal with a subsequent 100-km single-mode fiber （SMF） transmission link show its potential for future high-speed long-haul optical communication.

关键词： Bit error rate? ?Light amplifiers? ?Modulation? ?Phase shift keying

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Time-domain and Frequency-domain Analyses of PETT Oscillation in Press Pack IGBTs

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CSEE Journal of Power and Energy systems 2023年第2期9卷 682-695页

作者： Jiayu Fan Xiang Cui Xinling Tang Cheng Peng Zhibin Zhao Xiangrui Meng Xuebao Li Zhong Chen State Key Laboratory of Alternate Electrical Power system with Renewable Energy Sources North China Electrical Power UniversityBeijing 102206China Power semiconductor Devices Research Institute State Key Laboratory of Advanced Power Transmission TechnologyGlobal Energy Interconnection Research Institute Co.Ltd.Beijing 102209China department of Electrical engineering University of ArkansasFayettevilleAR 72701USA

Plasma extraction transit time(PETT)oscillation might appear in IGBT devices,which is harmful to the electromagnetic compatibility(EMC)of a renewable energy system.To eliminate this oscillation,its frequency-domain characteristics in wire-bonded IGBT devices have been extensively studied.However,the time-domain analysis of PETT oscillation,especially in Press Pack IGBT(PPI)devices,has not attracted enough attention yet.In this paper,PETT oscillations with multi-chips in PPI devices are systematically investigated by experiments.It is first reported there are multiple resonant oscillations at the tail period when multi-chips turn off.Oscillations overlap in the time domain waveforms,which lead PETT oscillation to be more serious in multi-chips.Then,PETT oscillation is divided into three different feedback states for the first time.For the IGBT chip in the PETT oscillation,its physical based model and behavior model are proposed,which further form the equivalent circuit as the two-port network.Moreover,it is indicated that only parallel resonances can lead to PETT oscillation,which is consistent with experiment results.

关键词： PETT oscillation press pack IGBTs timedomain analysis two-port network

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Capacitive Control of Spontaneously Induced Electrical Charge of Droplet by Electric Field-Assisted Pipetting

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Nano-Micro Letters 2015年第4期7卷 341-346页

作者： Horim Lee Dongwhi Choi Dong Sung Kim Geunbae Lim department of Mechanical engineering Pohang University of Science and Technology (POSTECH) Analysis Science & engineering Team Semiconductor R&D Center Samsung Electronics Co. Ltd.

The spontaneously generated electrical charge of a droplet dispensed from conventional pipetting is undesirable and unpredictable for most experiments that use pipetting.Hence,a method for controlling and removing the electrical charge needs to be developed.In this study,by using the electrode-deposited pipet tip(E-pipet tip),the charge-controlling system is newly developed and the electrical charge of a droplet is precisely controlled.The effect of electrolyte concentration and volume of the transferred solution to the electrical charge of a dispensed droplet is theoretically and experimentally investigated by using the equivalent capacitor model.Furthermore,a proof-of-concept example of the self-alignment and self-assembly of sequentially dispensed multiple droplets is demonstrated as one of the potential applications.Given that the electrical charge of the various aqueous droplets can be precisely and simply controlled,the fabricated E-pipet tip can be broadly utilized not only as a general charge-controlling platform of aqueous droplets but also as a powerful tool to explore fundamental scientific research regarding electrical charge of a droplet,such as the surface oscillation and evaporation of charged droplets.

关键词： Pipet tip Capacitive control Electrical charge Self-assembly

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Structure learning on Bayesian networks by finding the optimal ordering with and without priors

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Journal of systems engineering and Electronics 2018年第6期29卷 1209-1227页

作者： HE Chuchao GAO Xiaoguang GUO Zhigao department of system engineering Northwestern Polytechnical University

Ordering based search methods have advantages over graph based search methods for structure learning of Bayesian networks in terms on the efficiency. With the aim of further increasing the accuracy of ordering based search methods, we first propose to increase the search space, which can facilitate escaping from the local optima. We present our search operators with majorizations, which are easy to implement. Experiments show that the proposed algorithm can obtain significantly more accurate results. With regard to the problem of the decrease on efficiency due to the increase of the search space, we then propose to add path priors as constraints into the swap process. We analyze the coefficient which may influence the performance of the proposed algorithm, the experiments show that the constraints can enhance the efficiency greatly, while has little effect on the accuracy. The final experiments show that, compared to other competitive methods, the proposed algorithm can find better solutions while holding high efficiency at the same time on both synthetic and real data sets.

关键词： Bayesian network structure learning ordering search space graph search space prior constraint

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