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Application of Blockchain in Trusted Digital Vaccination Certificates

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China CDC weekly 2022年第6期4卷 106-110页

作者： Zixiong Zhao jiaqi ma Chinese Centre for Disease Control and Prevention BeijingChina

With the increasing number of coronavirus disease 2019(COVID-19)cases and worldwide vaccination coverage,‘vaccination passports’(vaccination certificates)may become a required permit for global travel,thereby supporting economic recovery.On march 7,2021,Wang Yi,State Councilor and Foreign Minister of China,announced the launch of the Chinese version of an‘international travel health certificate’at a press conference of the National People’s Congress and the Chinese Political Consultative Conference.He proposed a feasible‘Chinese solution’for promoting the recovery of the global economy and the facilitation of cross-border travel,and hoped that the international travel health certificate and vaccination passport can be mutually authenticated.

关键词： travel thereby mutually

Influence of Anteroposterior Symmetrical Aero-Wings on the Aerodynamic Performance of High-Speed Train

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Computer Modeling in Engineering & Sciences 2024年第4期139卷 937-953页

作者： Peiheng He Jiye Zhang Lan Zhang jiaqi Wang Yuzhe ma State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong UniversityChengdu610031China

The running stability of high-speed train is largely constrained by the wheel-rail coupling relationship,and the continuous wear between the wheel and rail surfaces will profoundly affect the dynamic performance of the train.In recent years,under the background of increasing train speed,some scientific researchers have proposed a new idea of using the lift force generated by the aerodynamic wings(aero-wing)installed on the roof to reduce the sprung load of the carriage in order to alleviate the wear and tear of the wheel and rail.Based on the bidirectional running characteristics of high-speed train,this paper proposes a scheme to apply aero-wings with anteroposterior symmetrical cross-sections on the roof of the train.After the verification of the wind tunnel experimental data,the relatively better airfoil section and extension formof anteroposterior symmetrical aero-wing is selected respectively in this paper,and the aero-wings are fixedly connected to the roof of the train through the mounting column to conduct aerodynamic simulation analysis.The research shows that:compared with the circular-arc and oval crosssections,this paper believes that the crescent cross-section can form greater aerodynamic lift force in a limited space.Considering factors such as aerodynamic parameters,ground effect,and manufacturing process,this paper proposes to adopt aero-wings with arc type extension form and connect them to the roof of the train through mounting columns with shuttle cross-section.When the roof of the train is covered with aero-wings and runs at high speed,the sprung load of the carriages can be effectively reduced.However,there are certain hidden dangers in the tail carriage due to the large amount of lift force,so,the intervention of the aero-wing lifting mechanism is required.At the same time,it is necessary to optimize the overall aerodynamic drag force reduction in the followup work.

关键词： Anteroposterior symmetrical aero-wing wheel-rail wear aerodynamic lift force ground effect numerical simulation

Effect of annealing on the electrical performance of N-polarity GaN Schottky barrier diodes

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Journal of Semiconductors 2024年第4期45卷 48-55页

作者： Nuo Xu Gaoqiang Deng Haotian ma Shixu Yang Yunfei Niu jiaqi Yu Yusen Wang Jingkai Zhao Yuantao Zhang State Key Laboratory of Integrated Optoelectronics College of Electronic Science and EngineeringJilin UniversityChangchun 130012China

A nitrogen-polarity(N-polarity)GaN-based high electron mobility transistor(HEMT)shows great potential for high-fre-quency solid-state power amplifier applications because its two-dimensional electron gas(2DEG)density and mobility are mini-mally affected by device scaling.However,the Schottky barrier height(SBH)of N-polarity GaN is low.This leads to a large gate leakage in N-polarity GaN-based HEMTs.In this work,we investigate the effect of annealing on the electrical characteristics of N-polarity GaN-based Schottky barrier diodes(SBDs)with Ni/Au electrodes.Our results show that the annealing time and tem-perature have a large influence on the electrical properties of N-polarity GaN SBDs.Compared to the N-polarity SBD without annealing,the SBH and rectification ratio at±5 V of the SBD are increased from 0.51 eV and 30 to 0.77 eV and 7700,respec-tively,and the ideal factor of the SBD is decreased from 1.66 to 1.54 after an optimized annealing process.Our analysis results suggest that the improvement of the electrical properties of SBDs after annealing is mainly due to the reduction of the inter-face state density between Schottky contact metals and N-polarity GaN and the increase of barrier height for the electron emis-sion from the trap state at low reverse bias.

关键词： nitrogen polarity GaN Schottky barrier diodes annealing interface state

Surface water resource attenuation attribution and patterns in Hai River Basin

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Science China Earth Sciences 2024年第5期67卷 1545-1560页

作者： Qingming WANG Yong ZHAO Hao WANG jiaqi ZHAI Yue ZHANG Fan HE Rong LIU Mengyang ma State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower Research(IWHR)Beijing 100038China Key Laboratory of Water Safety for Beijing-Tianjin-Hebei Region of Ministry of Water Resources Beijing 100038China General Institute of Water Resources and Hydropower Planning and Design Ministry of Water ResourcesBeijing 100120China

From 1956 to 2016,Hai River Basin suffered the most severe surface water resource attenuation among the 10 first-class river basins in China.Based on the surface water circulation process,and evolving characteristics of precipitation and underlying surface in Hai River Basin,this study attributed the causes of surface water resource attenuation to six primary impact factors,analyzed each factor's quantitative contribution,and revealed four patterns of surface water resource attenuation in Hai River Basin.The pattern of the dominant factor:comparing the 1980–2000 period with the 1956–1979period,the variation of precipitation is the dominant factor of which contribution is 7 billion m^(3),accounting for 59%of total11.7 billion m^(3);comparing the 2001–2016 period with the 1956–1979 period,the increasing of vegetation cover in mountainous area is the dominant factor of which contribution is 2.78 billion m3,accounting for 51%of total 4.9 billion m^(3).The pattern of spatial distributions:comparing the 2001–2016 period with the 1956–1979 period,mountainous areas were more affected by increasing vegetation cover which for example contributed 42%in Luan River Basin mountainous;the plains were more impacted by farmland ridge interception which for example contributed 51%in Beisi River Basin plains.The pattern of attenuation trend:comparing the 2001–2016 period with the 1980–2000 period,surface water resources in mountainous areas continued to decline,owing to the increasing water consumption of large-scale vegetation restoration,while the influence of the underlying surface changes on surface water resources in plains areas tended to remain stable.The pattern of reversible change:among factors led to surface water resource attenuation,the human activity,including vegetation cover increase,farmland ridge interception,and urbanization expansion,contributed 36%of the attenuation,which resulted in the variation of precipitation-runoff relation.This study improved the traditional attribution classification model of climate ch

关键词： Hai River Basin Surface water resources Contribution decomposition Quantitative contribution Attenuation patterns

A Modified Bi-Directional Evolutionary Structural Optimization Procedure with Variable Evolutionary Volume Ratio Applied to Multi-Objective Topology Optimization Problem

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Computer Modeling in Engineering & Sciences 2023年第4期135卷 511-526页

作者： Xudong Jiang jiaqi ma Xiaoyan Teng School of Mechanical and Power Engineering Harbin University of Science and TechnologyHarbin150080China College of Mechanical and Electrical Engineering Harbin Engineering UniversityHarbin150001China

Natural frequency and dynamic stiffness under transient loading are two key performances for structural design related to automotive,aviation and construction industries.This article aims to tackle the multi-objective topological optimization problem considering dynamic stiffness and natural frequency using modified version of bi-directional evolutionary structural optimization(BESO).The conventional BESO is provided with constant evolutionary volume ratio(EVR),whereas low EVR greatly retards the optimization process and high EVR improperly removes the efficient elements.To address the issue,the modified BESO with variable EVR is introduced.To compromise the natural frequency and the dynamic stiffness,a weighting scheme of sensitivity numbers is employed to form the Pareto solution space.Several numerical examples demonstrate that the optimal solutions obtained from the modified BESO method have good agreement with those from the classic BESO method.Most importantly,the dynamic removal strategy with the variable EVR sharply springs up the optimization process.Therefore,it is concluded that the modified BESO method with variable EVR can solve structural design problems using multi-objective optimization.

关键词： Bi-directional evolutionary structural optimization variable evolutionary volume ratio multi-objective optimization weighted sum topology optimization

High-performance wood-based thermoelectric sponges for thermal energy harvesting and smart buildings

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Nano Research 2024年第6期17卷 5349-5357页

作者： Ding Zhang Qi Li Yanjie Fang Peijia Bai Lili Liu jiaqi Guo Guangfa Wang Yuetong Zhou Rujun ma School of materials Science and Engineering National Institute for Advanced MaterialsSmart Sensing Interdisciplinary Science CenterNankai UniversityTianjin 300350China

The development of renewable woods for power generation can help improve the energy efficiency of buildings,and promote the concept design and implementation of“smart buildings”.Here,with specific chemical treatment and hydrothermal synthesis,we demonstrated the practical value of natural wood for thermoelectric power generation in smart buildings.The prepared wood-based thermoelectric sponges show high Seebeck coefficients of 320.5 and 436.6μV/K in the vertical and parallel directions of the longitudinal channel of wood.After 500 cycles of the compressive strain at 20%,the corresponding Seebeck coefficients increase up to 413.4 and 502.1μV/K,respectively,which is attributed to the improved contact and connection between tellurium thermoelectric nanowires.The Seebeck coefficients are much larger than those of most reported inorganic thermoelectric materials.Meanwhile,the thermoelectric sponges maintain excellent thermoelectric and mechanical stability.We further modeled the application value of wood-based thermoelectric sponges in smart buildings for power generation.Relatively high thermoelectric electricity can be obtained,such as in Beijing with over 1.5 million kWh every year,demonstrating the great potential in thermal energy harvest and energy supply.

关键词： wood thermoelectric effect thermal energy harvesting smart buildings energy supply

Degeneration Directory:a multi-omics web resource for degenerative diseases

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Protein & Cell 2024年第5期15卷 385-392页

作者： Haoteng Yan Changfa Lu Chenyang Lan Si Wang Weiqi Zhang Zan He Jinghao Hu jiaqi Ai Guang-Hui Liu Shuai ma Yuanchun Zhou Jing Qu State Key Laboratory of Membrane Biology Institute of ZoologyChinese Academy of SciencesBeijing 100101China State Key Laboratory of Stem Cell and Reproductive Biology Institute of ZoologyChinese Academy of SciencesBeijing 100101China Key Laboratory of Organ Regeneration and Reconstruction Institute of ZoologyChinese Academy of SciencesBeijing 100101China Advanced Innovation Center for Human Brain Protection and National Clinical Research Center for Geriatric DisordersXuanwu Hospital Capital Medical UniversityBeijing 100053China Aging Translational Medicine Center International Center for Aging and CancerBeijing Municipal Geriatric Medical Research CenterXuanwu HospitalCapital Medical UniversityBeijing 100053China Computer Network Information Center Chinese Academy of SciencesBeijing 100190China The Fifth People’s Hospital of Chongqing Chongqing 400062China Aging Biomarker Consortium Beijing 100101China CAS Key Laboratory of Genomic and Precision Medicine Beijing Institute of GenomicsChinese Academy of Sciences and China National Center for BioinformationBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China Sino-Danish College University of Chinese Academy of SciencesBeijing 101408China Beijing Institute for Stem Cell and Regenerative Medicine Beijing 100101China Institute for Stem Cell and Regeneration Chinese Academy of SciencesBeijing 100101China

Background of database.Organ degeneration refers to the gradual decline in organ function and structure deterioration that occurs during aging,which represents the greatest risk factor for various degenerative diseases,including cardiovascular diseases,neurodegenerative diseases,and osteoarthritis,etc.(Aging Biomarker et al.,2023;Becker et al.,2018;Cai et al.,2022).

关键词： Directory web Becker

Tetrathiafulvalene esters with high redox potentials and improved solubilities for non-aqueous redox flow battery applications

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Green Energy & Environment 2024年第5期9卷 899-908页

作者： Weikang Hu jiaqi Xu Nanjie Chen Zongcai Deng Yuekun Lai Dongyang Chen College of materials Science and Engineering Fuzhou UniversityFuzhou350116China College of Chemical Engineering Fuzhou UniversityFuzhou350116China

The exploitation of high performance redox-active substances is critically important for the development of non-aqueous redoxﬂow batteries.Herein,three tetrathiofulvalene(TTF)derivatives with different substitution groups,namely TTF diethyl ester(TTFDE),TTF tetramethyl ester(TTFTM),and TTF tetraethyl ester(TTFTE),are prepared and their energy storage properties are evaluated.It has been found that the redox potential and solubility of these TTF derivatives in conventional carbonate electrolytes increases with the number of ester groups.The battery with a catholyte of 0.2 mol L^(-1) of TTFTE delivers a speciﬁc capacity of more than 10 Ah L^(-1) at the current density of 0.5 C with two discharge voltage platforms locating at as high as 3.85 and 3.60 V vs.Li/Liþ.Its capacity retention can be improved from 2.34 Ah L^(-1) to 3.60 Ah L^(-1) after 100 cycles by the use of an anion exchange membrane to block the crossover of TTF species.The excellent cycling stability of the TIF esters is supported by their well-delocalized electrons,as revealed by the density function theory calculations.Therefore,the introduction of more and larger electron-withdrawing groups is a promising strategy to simultaneously increase the redox-potential and solubility of redox-active ma-terials for non-aqueous redoxﬂow batteries.

关键词： Non-aqueous redox flow batteries Tetrathiofulvarene Redox potential Solubility Substituent effect

Single-atom Co alloyed Ru for electrocatalytic nitrite reduction to ammonia

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Nano Research 2024年第5期17卷 3660-3666页

作者： Fuzhou Wang jiaqi Xiang Guike Zhang Kai Chen Ke Chu School of materials Science and Engineering Lanzhou Jiaotong UniversityLanzhou 730070China

Electrochemical converting NO_(2)^(-)into NH_(3)(NO_(2)RR)holds an enormous prospect to attain efficient NH_(3) electrosynthesis and polluted NO_(2)^(-)mitigation.Herein,we report single-atom Co alloyed Ru(Co_(1)Ru)as an efficient and durable NO_(2)RR catalyst.Extensive experimental and theoretical investigations reveal that single-atom Co alloying of Ru enables the construction of Co_(1)-Ru heteronuclear active sites to synergistically promote NO_(2)^(-)activation/hydrogenation while suppressing the competitive H_(2) evolution,rendering the greatly enhanced activity and selectivity of Co_(1)Ru towards the NO_(2)RR.Consequently,Co_(1)Ru assembled within a flow cell exhibits an impressive NH_(3) yield rate of 2379.2μmol·h^(-1)·cm^(-2) with an NH_(3)-Faradaic efficiency of 92%at a high current density of 415.9 ma·cm^(-2),which is among the highest NO_(2)RR performances reported to date.

关键词： electrochemical converting NO_(2)-into NH3 single-atom alloys theoretical computations industrial-level current density