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Enhancing thermoelectric performance in P-type Mg_(3)Sb_(2)-based Zintls through optimization of band gap structure and nanostructuring

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Journal of Materials Science & technology 2024年第3期170卷 25-32页

作者： Yi-bo Zhang Ji-Sheng Liang Chengyan Liu Qi Zhou Zhe Xu Hong-bo Chen Fu-cong Li Ying Peng Lei Miao Guangxi Key Laboratory of Information Material Engineering Research Center of Electronic Information Materials and DevicesMinistry of EducationSchool of Material Science and EngineeringGuilin University of Electronic TechnologyGuilin 541004China Guangxi Key Laboratory for Relativity Astrophysics Center on Nanoenergy ResearchGuangxi Key Laboratory of Processing for Nonferrous Metal and Featured MaterialsSchool of Physical Science&TechnologyGuangxi UniversityNanning 530004China Guangxi Key Laboratory of Precision Navigation Technology and Application Guilin University of Electronic TechnologySchool of Information and CommunicationGuilin 541004China

P-type Mg_(3)Sb_(2)-based Zintls have attracted considerable interest in the thermoelectric(TE)field due to their environmental friendliness and low ***,compared to their n-type counterparts,they show relatively low TE performance,limiting their application in TE *** this work,we simultaneously introduce Bi alloying at Sb sites and Ag doping at Mg sites into the Mg_(3)Sb_(2)to coopera-tively optimize the electrical and thermal properties for the first time,acquiring the highest ZT value of∼0.85 at 723 K and a high average ZT of 0.39 in the temperature range of 323-723 K in sample Mg_(2.94)Ag_(0.06)Sb_(1.9)Bi_(0.1).The first-principle calculations show that the codoping of Ag and Bi can shift the Fermi level into the valence band and narrow the band gap,resulting in the increased carrier concentration from 3.50×10^(17)cm^(-3)in the reference Mg 3 Sb 0.9 Bi 0.1 to∼7.88×10^(19)cm^(-3)in sample Mg 2.94 Ag 0.06 Sb 0.9 Bi *** a result,a remarkable power factor of∼778.9μW m^(-1)K^(-2)at 723 K is achieved in sample Mg 2.94 Ag 0.06 Sb 0.9 Bi ***,a low lattice thermal conductivity of∼0.48 W m^(-1)K^(-1)at 723 K is also obtained with the help of phonon scattering at the distorted lattice,point defects,and nano-precipitates in sample Mg 2.94 Ag 0.06 Sb 0.9 Bi *** synergistic effect of using the multi-element co-doping/-alloying to optimize electrical properties in Mg_(3)Sb_(2)holds promise for further improving the TE performance of Zintl phase materials or even others.

关键词： Thermoelectric materials Band engineering Nanostructuring P-type Mg_(3)Sb_(2) Ag and Bi Co-doping

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Self-Awakened Particle Swarm Optimization BN Structure Learning Algorithm Based on Search Space Constraint

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Computers, Materials & Continua 2023年第9期76卷 3257-3274页

作者： Kun Liu Peiran Li Yu Zhang Jia Ren Xianyu Wang Uzair Aslam Bhatti School of Information and Communication Engineering Hainan UniversityHaikou570228China Playload Research Center for Space Electronic Information System Academy of Space Electronic Information TechnologyXi’an710100China Research Center CRSC Communication&Information Group Co.Ltd.Beijing100070China

To obtain the optimal Bayesian network(BN)structure,researchers often use the hybrid learning algorithm that combines the constraint-based(CB)method and the score-and-search(SS)*** hybrid method has the problemthat the search efficiency could be improved due to the ample search *** search process quickly falls into the local optimal solution,unable to obtain the global *** on this,the Particle SwarmOptimization(PSO)algorithm based on the search space constraint process is *** the first stage,the method uses dynamic adjustment factors to constrain the structure search space and enrich the diversity of the initial *** the second stage,the update mechanism is redefined,so that each step of the update process is consistent with the current structure which forms a one-to-one *** the same time,the“self-awakened”mechanism is added to prevent precocious particles frombeing part of the *** the fitness value of the particle converges prematurely,the activation operation makes the particles jump out of the local optimal values to prevent the algorithmfromconverging too quickly into the local ***,the standard network dataset was compared with other *** experimental results showed that the algorithmcould find the optimal solution at a small number of iterations and a more accurate network structure to verify the algorithm’s effectiveness.

关键词： Bayesian network structure learning particle swarm optimization

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Control of GaN inverted pyramids growth on c-plane patterned sapphire substrates

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Journal of Semiconductors 2024年第6期45卷 92-96页

作者： Luming Yu Xun Wang Zhibiao Hao Yi Luo Changzheng Sun Bing Xiong Yanjun Han Jian Wang Hongtao Li Lin Gan Lai Wang Beijing National Research Center for Information Science and Technology Department of Electronic EngineeringTsinghua UniversityBei-jing 100084China Center for Flexible Electronics Technology Tsinghua UniversityBeijing 100084China

Growth of gallium nitride(GaN)inverted pyramids on c-plane sapphire substrates is benefit for fabricating novel devices as it forms the semipolar *** this work,GaN inverted pyramids are directly grown on c-plane patterned sapphire substrates(PSS)by metal organic vapor phase epitaxy(MOVPE).The influences of growth conditions on the surface morphol-ogy are experimentally studied and explained by Wulff *** competition of growth rate among{0001},{1011},and{1122}facets results in the various surface morphologies of GaN.A higher growth temperature of 985 ℃ and a lowerⅤ/Ⅲratio of 25 can expand the area of{}facets in GaN inverted *** the other hand,GaN inverted pyramids with almost pure{}facets are obtained by using a lower growth temperature of 930℃,a higherⅤ/Ⅲratio of 100,and PSS with pattern arrangement perpendicular to the substrate primary flat.

关键词： inverted pyramids GaN MOVPE crystal growth competition model

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Recent advances in breathable electronics

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Nano research 2023年第3期16卷 4130-4142页

作者： Zhuocheng Yan Jian Xiong Bin Wang Min Gao Guangqiang Yin Tao Hu Taisong Pan Xinzhong Wang Yuan Lin Department of Electronic Communication and Technology Shenzhen Institute of Information TechnologyShenzhen 518172China School of Materials and Energy University of Electronic Science and Technology of ChinaChengdu 610054China School of Information and Software Engineering University of Electronic Science and Technology of ChinaChengdu 610054China Engineering Cooperation on Applied Medicine Research Center University of Electronic Science and Technology of ChinaChengdu 610054China

The successful implementation of bioelectronic devices attached to living organism hinges on a number of material and device characteristics,including not only electrical and mechanical performances to gather physiological signals from living organism thus enabling status monitoring,but also permeability or breathability for gas/nutrient exchange between living organisms and surroundings to ensure minimum perturbation of the intrinsic biological ***,most bioelectronic devices built on planar polymeric substrates,such as polydimethylsiloxane(PDMS),polyurethane(PU),and polyimide(PI),lack efficient gas permeability,which may hinder the emission of volatile compounds from the surface of living organism,affecting the natural metabolism and reducing the comfort of ***,achieving permeability or breathability in bioelectronic devices is a significant ***,the devices made of gas-permeable materials with porous structures,that combine electronic components with daily garments,such as fibric and textile,offer exciting opportunities for breathable *** this review,several types of gas-permeable materials with their synthesis and processing routes are ***,two methods for measuring water vapor transmission rate of materials are discussed in ***,recent progress in the use of gaspermeable materials for the applications of plant-and skin-attached electronics is summarized systematically.

关键词： breathability gas permeability porous sponge foam nano materials plant electronics wearable electronics

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Mega-Constellations Based TT&C Resource Sharing: Keep Reliable Aeronautical Communication in an Emergency

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China Communications 2024年第2期21卷 1-16页

作者： Haoran Xie Yafeng Zhan Jianhua Lu Department of Electronic Engineering Tsinghua UniversityBeijing 100084China Beijing National Research Center for Information Science and Technology Tsinghua UniversityBeijing 100084China

With the development of the transportation industry, the effective guidance of aircraft in an emergency to prevent catastrophic accidents remains one of the top safety concerns. Undoubtedly, operational status data of the aircraft play an important role in the judgment and command of the Operational Control center(OCC). However, how to transmit various operational status data from abnormal aircraft back to the OCC in an emergency is still an open problem. In this paper, we propose a novel Telemetry, Tracking,and Command(TT&C) architecture named Collaborative TT&C(CoTT&C) based on mega-constellation to solve such a problem. CoTT&C allows each satellite to help the abnormal aircraft by sharing TT&C resources when needed, realizing real-time and reliable aeronautical communication in an emergency. Specifically, we design a dynamic resource sharing mechanism for CoTT&C and model the mechanism as a single-leader-multi-follower Stackelberg game. Further, we give an unique Nash Equilibrium(NE) of the game as a closed form. Simulation results demonstrate that the proposed resource sharing mechanism is effective, incentive compatible, fair, and reciprocal. We hope that our findings can shed some light for future research on aeronautical communications in an emergency.

关键词： aeronautical emergency communication mega-constellation networked TT&C resource allocation stackelberg game

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Breaking the efficiency limitations of dissipative Kerr solitons using nonlinear couplers

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Science China(Physics,Mechanics & Astronomy) 2024年第3期67卷 88-94页

作者： Ming Li Xiao-Xiao Xue Yan-Lei Zhang Xin-Biao Xu Chun-Hua Dong Guang-Can Guo Chang-Ling Zou CAS Key Laboratory of Quantum Information University of Science and Technology of ChinaHefei 230026China CAS Centerfor Excellence in Quantum Information and Quantum Physics University of Science and Technology of ChinaHefei 230026China Department of Electronic Engineering Beijing National Research Center for Information Science and TechnologyTsinghua University Beijing 100084China

Dissipative Kerr solitons(DKS) have long been suffering from poor power conversion efficiency when driven by continuous-wave lasers. By deriving the critical coupling condition of a multimode nonlinear optics system in a generalized theoretical framework,two efficiency limitations of the conventional pump method of DKS are revealed: the effective coupling rate is too small and is also power-dependent. A general approach is provided to resolve this challenge by introducing two types of nonlinear couplers to couple the soliton cavity and CW input through nonlinear processes. The collective coupler opens multiple coupling channels and the self-adaptive coupler builds a power-independent effective external coupling rate to the DKS for approaching the generalized critical coupling condition, which promises near-unity power conversion efficiencies. For instance, a conversion efficiency exceeding 90% is predicted for aluminum nitride microrings with a nonlinear coupler utilizing second-harmonic generation. The mechanism applies to various nonlinear processes, including Raman and Brillouin scattering, and thus paves the way for micro-solitons toward practical applications.

关键词： Kerr frequency comb conversion efficiency nonlinear coupler

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research of synthesis and neural network training on double quantum dot colorimetric fluorescent probe for freshness detection

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Frontiers of Chemical Science and Engineering 2024年第10期18卷 145-157页

作者： Caihong Lv Yuewei Zheng Zhihao Guan Jun Qian Houbin Li Xinghai Liu Hubei Engineering Technology Research Center of Spectrum and Imaging Instrument Electronic Information SchoolWuhan UniversityWuhan 430072China School of Nursing Wuhan UniversityWuhan 430072China

There are many disadvantages such as small detection range and environmental restrictions on application conditions,when the single quantum dot powder or solution is used for fluorescent probe *** this paper,the blue fluorescent silicon quantum dots and green fluorescent carbon quantum dots were prepared,and their fluorescence color changes after mixing in different proportions were investigated under different pH *** the two quantum dots were mixed with a concentration of 0.1 mg·mL^(-1) and a mass ratio of 1:1,the fluorescence color change could be better displayed at a pH from 1 to ***,the double quantum dots were prepared into two forms(ink and film),successfully realizing the device application of the fluorescent *** films and inkjet-printed labels were used to test the spoilage of food(pork,milk,etc.),and the color change data of the labels were collected during the spoilage *** data were used for neural network training to predict the spoilage changes of foods.

关键词： silicon quantum dots carbon quantum dots fluorescent probe pH freshness

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Monitoring firn and wet snow on mountain glaciers:polarization and orbit effects

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地球空间信息科学学报（英文版） 2024年第3期27卷 761-772页

作者： Ying Huang Lei Huang Tobias Bolch Institute of Geology China Earthquake AdministrationBeijingChina International Research Center of Big Data for Sustainable Development Goals BeijingChina Aerospace Information Research Institute Chinese Academy of SciencesBeijingChina International Research Center of Big Data for Sustainable Development Goals BeijingChina Aerospace Information Research Institute Chinese Academy of SciencesBeijingChina Institute of Geodesy Graz University of TechnologyGrazAustria

Mountain glaciers are sensitive to climate variability and can be of great importance for downstream populations due to their hydrological *** Aperture Radar(SAR)images are often used to monitor the characteristics of glaciers based on the back-scattering ***,the influence of satellite orbit and polarization when collecting images for wide regions has not been well *** study focuses on the extraction of wet snow in summer and firn in winter in West Kunlun Shan and the Tibet Interior Mountains by using Sentinel-1 C-band SAR *** investigated regions have different climate *** compare backscatter coefficient distributions for wet snow and firn,derived from maximum likelihood classification under various polarizations,alongside their respective ratios and show that polarization has a minor impact on the identification and monitoring of both wet snow and ***,a comparison of the wet snow ratios at different satellite orbits reveals notable differences between ascending and descending orbits in *** furthermore show,by analyzing weather stations on glaciers,that such effect can be related to the different acquisition time and different temperatures in the morning and afternoon and therefore to the *** contrast,firn ratios across different orbits show less variation in winter,and the monitoring results consistently align with the patterns of ablation and accumulation typical under both climatic *** findings demonstrate glaciers'sensitivity to temperature fluctuations and the radar wave's responsiveness to surface ***,when employing SAR for glacier monitoring,it is crucial to consider the influence of orbit and polarization,in combination with temperature variations,and whether the season is winter or summer.

关键词： Continental glacier Synthetic Aperture Radar(SAR) wet snow firn radar glacier zones

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Adaptive Leader-Follower Consensus Control of Multiple Flexible Manipulators With Actuator Failures and Parameter Uncertainties

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IEEE/CAA Journal of Automatica Sinica 2023年第4期10卷 1020-1031页

作者： Yu Liu Lin Li School of Automation Science and Engineering South China University of TechnologyGuangzhou 510640 Research and Development Center of Precision Electronic Manufacturing Technology Guangzhou Institute of Modern Industrial TechnologyGuangzhou 511458China

In this paper,the leader-follower consensus problem for a multiple flexible manipulator network with actuator failures,parameter uncertainties,and unknown time-varying boundary disturbances is *** purpose of this study is to develop distributed controllers utilizing local interactive protocols that not only suppress the vibration of each flexible manipulator but also achieve consensus on joint angle position between actual followers and the virtual *** the accomplishment of the reconstruction of the fault terms and parameter uncertainties,the adaptive neural network method and parameter estimation technique are employed to compensate for unknown items and bounded ***,the Lyapunov stability theory is used to demonstrate that followers’angle consensus errors and vibration deflections in closed-loop systems are uniformly ultimately ***,the numerical simulation results confirm the efficacy of the proposed controllers.

关键词： Actuator failures leader-follower consensus multiple flexible manipulators neural network parameter uncertainties

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Iterative Model Predictive Control for Automatic Carrier Landing of Carrier-Based Aircrafts Under Complex Surroundings and Constraints

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Journal of Shanghai Jiaotong university(Science) 2024年第4期29卷 712-724页

作者： ZHANG Xiaotian HE Defeng LIAO Fei College of Information Engineering Zhejiang University of TechnologyHangzhou310023China Aerospace Technology Institute China Aerodynamics Research and Development CenterMianyang621000SichuanChina

This paper considers the automatic carrier landing problem of carrier-based aircrafts subjected to constraints,deck motion,measurement noises,and unknown *** iterative model predictive control(MPC)strategy with constraints is proposed for automatic landing control of the ***,the long short-term memory(LSTM)neural network is used to calculate the adaptive reference trajectories of the *** the Sage-Husa adaptive Kalman filter and the disturbance observer are introduced to design the composite ***,an iterative optimization algorithm is presented to fast solve the receding horizon optimal control problem of MPC based on the Lagrange’s ***,some sufficient conditions are derived to guarantee the stability of the landing system in a closed loop with the ***,the simulation results of F/A-18A aircraft show that compared with the conventional MPC,the presented MPC strategy improves the computational efficiency by nearly 56%and satisfies the control performance requirements of carrier landing.

关键词： automatic carrier landing model predictive control(MPC) long short-term memory(LSTM)neural network stability computational efficiency

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