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化学科学与工程前沿:英文版 2023年第9期17卷 1231-1243页

作者： Lin Wang Yinjie Kuang Qian Cui Junyu Shi Liubin Song Qionghua Li Tianjian Peng Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation School of Chemistry and Chemical EngineeringChangsha University of Science and TechnologyChangsha410114China Guizhou Dalong Huicheng New Material Co. Ltd.Tongren554000China

The cycling stability of SnO_(2)anode as lithium-ion battery is poor due to volume expansion.Polyimide coatings can effectively confine the expansion of SnO_(2).However,linear polyimides are easily dissolved in ester electrolytes and their carbonyls is not fully utilized during charging/discharging process.Herein,the SnO_(2)enclosed with anthraquinone-based polyimide/reduced graphene oxide composite was prepared by self-assembly.Carbonyls from the anthraquinone unit provide fully available active sites to react with Li^(+),improving the utilization of carbonyl in the polyimide.More exposed carbonyl active sites promote the conversion of Sn to SnO_(2)with electrode gradual activation,leading to an increase in reversible capacity during the charge/discharge cycle.In addition,the introduction of reduced graphene oxide cannot only improve the stability of polyimide in the electrolyte,but also build fast ion and electron transport channels for composite electrodes.Due to the multiple effects of anthraquinone-based polyimide and the synergistic effect of reducing graphene oxide,the composite anode exhibits a maximum reversible capacity of 1266 mAh·g^(−1) at 0.25 A·g^(−1),and maintains an excellent specific capacity of 983 mAh·g^(−1) after 200 cycles.This work provides a new strategy for the synergistic modification of SnO_(2).

关键词： anthraquinone-based polyimide multi-effect tin dioxide reduced graphene oxide lithium-ion battery

A small signal coupling model for predicting the coupling between LNAs

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Journal of Semiconductors 2017年第7期38卷 97-102页

作者： Junyu Shi Dasheng Cui Yuming Wu Beijing Institute of Technology Beijing 100081 China

A small signal coupling model is developed to analyze the coupling between two LNAs. The mutual inductance between the adjacent on-chip inductors is considered responsible for this coupling. A set of formulas have been derived to quantitatively predict the coupling effects. Based on our analysis, a quick estimation can be made to see which pair of inductors plays a key role in evaluating the coupling between the LNAs. Source inductors of two LNAs are placed closely while the load inductors are far apart according to the analysis. To validate the proposed theory, two 2 GHz LNAs are fabricated. The LNAs have a peak gain of 18 dB and NF of 1.4 dB. The coupling between the LNAs is –30 dB.

关键词： low noise amplifier（LNA） small signal model on-chip inductors coupling

An approximation algorithm for lower-bounded k-median with constant factor

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Science China(Information Sciences) 2022年第4期65卷 93-101页

作者： Xiaoliang WU Feng shi Yutian GUO Zhen ZHANG junyu HUANG Jianxin WANG School of Computer Science and Engineering Central South University Hunan Provincial Key Lab on Bioinformatics Central South University School of Frontier Crossover Studies Hunan University of Technology and Business

The lower-bounded k-median problem plays a key role in many applications related to privacy protection, which requires that the amount of assigned client to each facility should not be less than the requirement. Unfortunately, the lower-bounded clustering problem remains elusive under the widely studied k-median objective. Within this paper, we convert this problem to the capacitated facility location problem and successfully give a(516+ε)-approximation for this problem.

关键词： Approximation algorithm approximation algorithm $k$-median lower-bounded $k$-median

Design and Realization of Schottky Barrier Didoes in 130nm CMOS Process

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Journal of Beijing Institute of Technology 2017年第2期26卷 223-227页

作者： Junyu Shi Dasheng Cui Haidong Hao Haixia Wu Xin Lyu School of Information and Electronics Beijing Institute of Technology Beijing 100081 China

A polysilicon separated CMOS Schottky barrier diode is designed and tested in this study.By replacing the shallow trench isolation（STI）of a ploy ring,the series resistances of Schottky diodes are reduced,leading to an improvement in cut-off frequencies.The device structure is detailed and a device model is developed.Our analysis on the device shows that the cut-off frequency increases with the decreasing of the Schottky contact area.Based on this observation,the Schottky contact area is set to0.38×0.38μm^2,which is the minimum contact diffusion area allowed by the process flow.The distance between the anode and the cathode is also discussed.Diodes with different dimensions are fabricated and measured.Through extensive measurements,the optimum dimensions are obtained.Bondpads with a reduced area are used to improve the measurement accuracy.The measurement results show that these diodes can achieve a cut-off frequency of 1.5 THz.Thus,it is possible to use these diodes in THz detection.

关键词： Schottky barrier diodes cut-off frequency silicon THz detection

HMGB1 from Astrocytes Promotes EAE by Influencing the Immune Cell Infiltration-Associated Functions of BMECs in Mice

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Neuroscience Bulletin 2022年第11期38卷 1303-1314页

作者： Junyu Shi Yifan Xiao Na Zhang Mengya Jiao Xuhuan Tang Chan Dai Chenchen Wang Yong Xu Zheng Tan Feili Gong Fang Zheng Department of Immunology School of Basic MedicineTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430030China Key Laboratory of Organ Transplantation Ministry of EducationNHC Key Laboratory of Organ TransplantationKey Laboratory of Organ TransplantationChinese Academy of Medical SciencesWuhan 430030China Department of Pathology and Pathophysiology School of MedicineJianghan UniversityWuhan 430056China

High mobility group box 1(HMGB1)has been reported to play an important role in experimental autoimmune encephalomyelitis(EAE).Astrocytes are important components of neurovascular units and tightly appose the endothelial cells of microvessels by their perivascular endfeet and directly regulate the functions of the blood-brain barrier.Astrocytes express more HMGB1 during EAE while the exact roles of astrocytic HMGB1 in EAE have not been well elucidated.Here,using conditional-knockout mice,we found that astrocytic HMGB1 depletion decreased morbidity,delayed the onset time,and reduced the disease score and demyelination of EAE.Meanwhile,there were fewer immune cells,especially pathogenic T cells infiltration in the central nervous system of astrocytic HMGB1 conditional-knockout EAE mice,accompanied by up-regulated expression of the tight-junction protein Claudin5 and down-regulated expression of the cell adhesion molecules ICAM1 and VCAM1 in vivo.In vitro,HMGB1 released from astrocytes decreased Claudin5 while increased ICAM1 and VCAM1 expressed by brain microvascular endothelial cells(BMECs)through TLR4 or RAGE.Taken together,our results demonstrate that HMGB1 derived from astrocytes aggravates EAE by directly influencing the immune cell infiltration-associated functions of BMECs.

关键词： HMGB1 Astrocytes Experimental autoimmune encephalomyelitis Blood-brain barrier

Coverage enhancement for 6G satellite-terrestrial integrated networks: performance metrics, constellation configuration and resource allocation

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Science China(Information Sciences) 2023年第3期66卷 40-59页

作者： Min SHENG Di ZHOU Weigang BAI junyu LIU Haoran LI Yan shi Jiandong LI State Key Laboratory of Integrated Service Networks Xidian University Department of Broadband Communication Peng Cheng Laboratory

Since the base station-centric wireless coverage mode of 5G is difficult to support future stereoscopic global wireless coverage demands, the future infrastructure of 6G satellite-terrestrial integrated network(STIN) with mega constellations will extend from the terrestrial network to the integrated satellite-terrestrial architecture, so as to realize the improvement of wireless coverage capability through extending the spatial and temporal coverage. However, what are the specific quantitative indicators of wireless coverage? What is the basis for the effect of network configuration with mega constellations on coverage performance? How to form non-uniform coverage through intelligent resource scheduling to match non-uniformly distributed service requirements in the future 6G STIN? The aforementioned unknown fundamental problems have become a bottleneck restricting the further development of coverage expansion in the future 6G STIN. In this paper,we start with the evolution route of wireless coverage and the vision of 6G coverage and propose coverage performance evaluation metrics in 6G STINs from the perspective of signal coverage, capacity coverage, and service coverage. Furthermore, we investigate the relationship between coverage structure and coverage capability in 6G STINs with mega constellations and we find network structure characteristics suitable for 6G non-uniform service requirements, thus guiding constellation design in 6G STINs by analyzing and comparing the coverage performance of several typical mega constellations. Afterwards, we explore the application of artificial intelligence in resource collaboration to provide technology reference to enhance coverage capability for dynamic 6G service demands. Finally, we analyze possible technical challenges for improving service coverage performance in 6G STINs to provide researchers with new ideas.

关键词： 6G satellite-terrestrial integrated networks on-demand wireless coverage performance metrics constellation configuration intelligent resource scheduling

Energy-efficient Medium-speed Maglev Train Control Based on Resistance Fitting

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Energy-efficient Medium-speed Maglev Train Control Based on ...

A WiFi Fingerprint Based High-Adaptability Indoor Localization via Machine Learning

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作者： Junyu Shi Wenjin Yue Yiwei Wang Weifeng Zhong Beijing Jiaotong University

Compared with traditional rail transit systems with the same transport capacity, the maglev transport has great advantages in terms of safety, energy conservation and environmental protection. Since the maglev train is driven by the electromagnetic force and does not touch the rail when it is running, the form of basic resistance acting on the maglev train is more complex than that of the traditional train. This imposes extra challenges to obtain the energy-efficient control strategies for maglev trains. In this paper, we consider the energy-efficient control problem for medium-speed maglev trains whose basic resistance is a piecewise-quadratic function of train speed. Firstly, the piecewise-quadratic function is approximated as a single quadratic function by using the least square fitting method. Then, by applying control parameterization and time-scaling transformation technique, the traction and braking forces of the maglev train are approximated as piecewise-constant values at each track segment, and the energy-efficient maglev train control problem is transformed into a finite-dimensional optimization problem which is then solved by using the gradient-based sequential quadratic programming（SQP） algorithm. Finally, the effectiveness and performance of the proposed method are demonstrated by two numerical examples. The simulation results show that the proposed algorithm can fit the original resistance function well, and the obtained control strategy based on the fitted resistance results in lower energy consumption with higher computation efficiency.

关键词： Medium-speed Maglev Train Energy-efficient Train Control Resistance Fitting Control Parameterization Time-scaling Transformation

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China Communications 2020年第7期17卷 247-259页

作者： Jianzhe Xue junyu Liu Min Sheng Yan shi Jiandong Li School of Telecommunication Engineering Xidian UniversityXi’an 710071China State Key Laboratory of Integrated Service Networks Xidian UniversityXi’an 710071China

For received signal strength(RSS)fingerprint based indoor localization approaches,the localization accuracy is significantly influenced by the RSS variance,device heterogeneity and environment complexity.In this work,we present a high-adaptability indoor localization(HAIL)approach,which leverages the advantages of both relative RSS values and absolute RSS values to achieve robustness and accuracy.Particularly,a backpropagation neural network(BPNN)is devised in HAIL to measure the fingerprints similarities based on absolute RSS values.With this aid,the characteristics of the applied area could be specially learned such that HAIL could be adaptive to different environments.The experiments demonstrate that HAIL achieves high localization accuracy with the average localization error of 0.87 m in the typical environments.Moreover,HAIL has the minimum amount of large errors and decreases the average localization error by about 30%~50%compared with the existing approaches.

关键词： WiFi absolute error

VOC emission caps constrained by air quality targets based on response surface model:A case study in the Pearl River Delta Region,China

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Journal of Environmental Sciences 2023年第1期123卷 430-445页

作者： Ya’nan Hu Bowen shi Xin Yuan Chuanzeng Zheng Qing’e Sha Yufan Yu Zhijiong Huang junyu Zheng Institute for Environmental and Climate Research Jinan UniversityGuangzhou 511436China Guangdong Polytechnic of Environmental Protection Engineering Guangzhou 528216China

Because of the recent growth in ground-level ozone and increased emission of volatile organic compounds(VOCs),VOC emission control has become a major concern in China.In response,emission caps to control VOC have been stipulated in recent policies,but few of them were constrained by the co-control target of PM_(2.5)and ozone,and discussed the factor that influence the emission cap formulation.Herein,we proposed a framework for quantification of VOC emission caps constrained by targets for PM_(2.5)and ozone via a new response surface modeling(RSM)technique,achieving 50%computational cost savings of the quantification.In the Pearl River Delta(PRD)region,the VOC emission caps constrained by air quality targets varied greatly with the NOxemission reduction level.If control measures in the surrounding areas of the PRD region were not considered,there could be two feasible strategies for VOC emission caps to meet air quality targets(160μg/m^(3)for the maximum 8-hr-average 90th-percentile(MDA8-90%)ozone and 25μg/m^(3)for the annual average of PM_(2.5)):a moderate VOC emission cap with60%NOxemission reductions.If the ozone concentration target were reduced to 155μg/m^(3),deep NOxemission reductions is the only feasible ozone control measure in PRD.Optimization of seasonal VOC emission caps based on the Monte Carlo simulation could allow us to gain higher ozone benefits or greater VOC emission reductions.If VOC emissions were further reduced in autumn,MDA8-90%ozone could be lowered by 0.3-1.5μg/m^(3),equaling the ozone benefits of 10%VOC emission reduction measures.The method for VOC emission cap quantification and optimization proposed in this study could provide scientific guidance for coordinated control of regional PM_(2.5)and O_(3)pollution in China.

关键词： Volatile organic compounds Emission caps Air quality targets Response surface model Monte Carlo(MC)simulations

A nonchlorinated solvent-processed polymer semiconductor for high-performance ambipolar transistors

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National Science Review 2022年第4期9卷 139-147页

作者： Jie Yang Yaqian Jiang Zhiyuan Zhao Xueli Yang Zheye Zhang Jinyang Chen junyu Li Wei shi Shuai Wang Yunlong Guo Yunqi Liu Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic SolidsInstitute of ChemistryChinese Academy of Sciences School of Chemistry and Chemical Engineering Huazhong University of Science and Technology

Ambipolar polymer semiconductors are potentially serviceable for logic circuits, light-emitting field-effect transistors(LFETs) and polymer solar cells(PSCs). Although several high-performance ambipolar polymers have been developed, their optoelectronic devices are generally processed from toxic chlorinated solvents. To achieve the commercial applications of organic FETs(OFETs), the polymers should be processed from nonchlorinated solvents, instead of chlorinated solvents. However, most conjugated polymers show poor solubility in nonchlorinated solvents. It is of great importance to develop ambipolar polymers that can be processed from nonchlorinated solvents. Here, we develop a nonchlorinated solvent processed polymer named poly[7-fluoro-N, N′-di(4-decyltetradecyl)-7′-azaisoindigo-6′,6′′-(thieno[3,2-b]thiophene-2,5-diyl)-7′′′-fluoro-N′′, N′′′-di(4-decyltetradecyl)-7′′-azaisoindigo-6,6′′′-([2,2′′-bithiophene]-5,5′′-diyl)](PITTI-BT) by designing a monomer with a large molar mass. The polymer displays good solubility in p-xylene(PX). Well-aligned films of PITTI-BT are achieved by an off-center spin-coating(SC) method. Based on the high-quality films, the OFETs fabricated from PX solution achieve record ambipolar performance with hole and electron mobilities of 3.06 and2.81 cm~2 V-1s-1, respectively. The combination of nonchlorinated solvents and good alignment process offers an effective and eco-friendly approach to obtain high-performance ambipolar transistors.

关键词： nonchlorinated solvent high performance ambipolar transistor alignment