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Local tetragonal distortion of Pt alloy catalysts for enhanced oxygen reduction reaction efficiency

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Carbon Energy 2024年第7期6卷 41-52页

作者： Xiaoke li Xiao Duan Kang Hua Yongkang Wu Zhiyan rui rui Ding Aidong li Chen Ouyang Jia li Ting li Jianguo liu National Laboratory of Solid-State Microstructures College of Engineering and Applied Sciencesand Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjingChina Long-life Fuel Cell Key Laboratory in Sichuan Province Dongfang Electric(Chengdu)Hydrogen Fuel Cell Technology Co.Ltd.ChengduChina Institute of Energy Power Innovation North China Electric Power UniversityBeijingChina

Platinum-based alloy nanoparticles are the most attractive catalysts for the oxygen reduction reaction at present,but an in-depth understanding of the relationship between their short-range structural information and catalytic performance is still ***,we present a synthetic strategy that uses transition-metal oxide-assisted thermal ***/C catalysts with localized tetragonal distortion were obtained by controlling the thermal diffusion process of transition-metal *** localized structural distortion induced a significant strain effect on the nanoparticle surface,which further shortened the length of the Pt-Pt bond,improved the electronic state of the Pt surface,and enhanced the performance of the ***/C catalysts with special short-range structures achieved excellent mass activity(2.27 Amg_(Pt)^(-1))and specific activity(3.34 A cm^(-2)).In addition,the localized tetragonal distortion-induced surface compression of the Pt skin improved the stability of the *** mass activity decreased by only 13%after 30,000 *** catalyst activity and excellent durability have also been demonstrated in the proton exchange membrane fuel cell *** study provides valuable insights into the development of advanced Pt-based nanocatalysts and paves the way for reducing noble-metal loading and increasing the catalytic activity and catalyst stability.

关键词： electrocatalysts fuel cells local tetragonal distortion oxygen reduction

Transient Monte Carlo simulation of phonon transport in silicon nanofilms with the local heat source

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Science China(Technological Sciences) 2024年第7期67卷 2087-2098页

作者： li JiaQi CAI JiuQing li rui liU ZhiChun liU Wei School of Energy and Power Engineering Huazhong University of Science and TechnologyWuhan 430074China Wuhan Second Ship Design and Research Institute Wuhan 430205China

Accurate prediction of junction temperature is crucial for the efficient thermal design of silicon nano-devices. In nano-scale semiconductor devices, significant ballistic effects occur due to the mean free path of phonons comparable to the heat source size and device scale. We employ a three-dimensional non-gray Monte Carlo simulation to investigate the transient heat conduction of silicon nanofilms with both single and multiple heat sources. The accuracy of the present method is first verified in the ballistic and diffusion limits. When a single local heat source is present, the width of the heat source has a significant impact on heat conduction in the domain. Notably, there is a substantial temperature jump at the boundary when the heat source width is 10 *** increasing heat source width, the boundary temperature jump weakens. Furthermore, we observe that the temperature excitation rate is independent of the heat source width, while the temperature influence range expands simultaneously with the increase in heat source width. Around 500 ps, the temperature and heat flux distribution in the domain stabilize. In the case of dual heat sources, the hot zone is broader than that of a single heat source, and the temperature of the hot spot decreases as the heat source spacing increases. However, the mean heat flux remains unaffected. Upon reaching a spacing of 200 nm between the heat sources, the peak temperature in the domain remains unchanged once a steady state is reached. These findings hold significant implications for the thermal design of silicon nano-devices with local heat sources.

关键词： phonon transport Monte Carlo simulation transient heat conduction silicon nanofilms local heat source

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Research on fast detection method of infrared small targets under resource-constrained conditions

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JOURNAL OF INFRARED AND MILliMETER WAVES 2024年第4期43卷 582-587页

作者： Zhang, rui liu, Min li, Zheng Xiamen Univ Technol Sch Optoelect & Comunicat Engn Xiamen 361024 Peoples R China Chinese Acad Sci Shanghai Inst Tech Phys Shanghai 200083 Peoples R China

Infrared small target detection is a common task in infrared image processing. Under limited computational resources. Traditional methods for infrared small target detection face a trade-off between the detection rate and the accuracy. A fast infrared small target detection method tailored for resource-constrained conditions is proposed for the YOLOv5s model. This method introduces an additional small target detection head and replaces the original Intersection over Union (IoU) metric with Normalized Wasserstein Distance (NWD), while considering both the detection accuracy and the detection speed of infrared small targets. Experimental results demonstrate that the proposed algorithm achieves a maximum effective detection speed of 95 FPS on a 15 W TPU, while reaching a maximum effective detection accuracy of 91. 9 AP@0.5, effectively improving the efficiency of infrared small target detection under resource-constrained conditions.

关键词： infrared UAV image fast small object detection low impedance loss function

Evolution of HIV/AIDS Prevention and Control Policies in China:A Grounded Theory Approach

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China CDC weekly 2024年第1期6卷 12-22页

作者： Huang li rui Gao Chichen Zhang School of Public Health Southern Medical UniversityGuangzhou CityGuangdong ProvinceChina School of Health Management Southern Medical UniversityGuangzhou CityGuangdong ProvinceChina Key Laboratory of Philosophy and Social Sciences of Colleges and Universities in Guangdong Province for Collaborative Innovation of Health Management Policy and Precision Health Service Southern Medical UniversityGuangzhou CityGuangdong ProvinceChina Graduate School Xi’an Jiaotong-Liverpool UniversitySuzhou CityJiangsu ProvinceChina School of Political Science and Public Administration Soochow UniversitySuzhou CityJiangsu ProvinceChina

Objective:This study aims to provide a theoretical foundation for the development and practical application of human immunodeficiency virus(HIV)/acquired immunodeficiency syndrome(AIDS)prevention and control policy systems in China by scrutinizing,analyzing,and synthesizing the evolution of Chinese policies in this ***:Utilizing grounded theory,we employed NVivo12 software to perform text content analysis,mining,and coding classification,along with visualization techniques,on policy texts sourced from Chinese government platforms,including the official website of China’s State *** considered four analytical dimensions—time,subject,type,and ***:The National Health Commission and the State Council emerged as the primary entities engaged in policymaking for HIV/AIDS in *** identified four distinct stages in the evolution of these policies,culminating in a novel‘sun-shaped’HIV/AIDS prevention and control policy network model with an emphasis on‘knowledge,attitude,and practice’at its nucleus,which aligns with national conditions and societal ***,the focal groups of these policies have been dynamically refined and updated over ***:Our findings introduce a‘sunshaped’HIV/AIDS prevention and control policy network model specific to *** observed a conceptual policy shift towards prioritizing overall human health rather than confining the focus to disease ***,in light of China’s growing elderly population,the imperative to address HIV/AIDS prevention and control among older adults is an issue that warrants increased attention.

关键词： prevention HIV/AIDS policy

Magnetic resonance-guided focused ultrasound for essential tremor:a prospective,single center,single-arm study

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Neural Regeneration Research 2024年第9期19卷 2075-2080页

作者： rui zong Xuemei li Chunyu Yin Jianfeng He Dekang Zhang Xiangbing Bian lichao Huang Jiayou Zhou Zhipei ling lin Ma Xin Lou Longsheng Pan Xinguang Yu Seniro Department of Neurosurgery The First Medical Center of the PLA General HospitalBeijingChina Clinics of Cadre Department of OutpatientThe First Medical Center of the PLA General HospitalBeijingChina Department of Radiology The First Medical Center of the PLA General HospitalBeijingChina

The safety and effectiveness of magnetic resonance-guided focused ultrasound thalamotomy has been broadly established and validated for the treatment of essential *** 2018,the first magnetic resonance-guided focused ultrasound system in Chinese mainland was installed at the First Medical Center of the PLA General *** prospective,single center,open-label,single-arm study was part of a worldwide prospective multicenter clinical trial(*** Identifier:NCT03253991)conducted to confirm the safety and efficacy of magnetic resonance-guided focused ultrasound for treating essential tremor in the local *** 2019 to 2020,10 patients with medication refractory essential tremor were recruited into this open-label,single arm *** treatment efficacy was determined using the Clinical Rating Scale for *** was evaluated according to the incidence and severity of adverse *** of the subjects underwent a unilateral thalamotomy targeting the ventral intermediate *** the baseline assessment,the estimated marginal mean of the Clinical Rating Scale for Tremor total score was 58.3±3.6,and this improved after treatment to 23.1±6.4 at a 12-month follow-up assessment.A total of 50 adverse events were recorded,and 2 were defined as *** most common intraoperative adverse events were nausea and *** most frequent postoperative adverse events were paresthesia and equilibrium *** of the adverse events were mild and usually disappeared within a few *** findings suggest that magnetic resonance-guided focused ultrasound for the treatment of essential tremor is effective,with a good safety profile,for patients in Chinese mainland.

关键词： efficacy essential tremor magnetic resonance-guided focused ultrasound(MRgFUS) movement disorder safety stereotactic therapy thalamotomy ventral intermediate nucleus

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CO_(2) corrosion of X80 steel welded joints under micro-turbulence induced by welding reinforcement height

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Journal of Iron and Steel Research International 2024年第4期31卷 1015-1032页

作者： Xiao-hui Dou Bin li zong-hao He Xin-wei Zhang Da-lei Zhang Yan li School of Materials Science and Engineering China University of Petroleum(East China)Qingdao 266580ShandongChina School of Energy and Power Engineering Jiangsu UniversityZhenjiang 212013JiangsuChina

Corrosion failure accidents owing to flow erosion and pipeline corrosion frequently occur during *** welding reinforcement height(WRH)can induce locally micro-turbulent flow field,which aggravates local corrosion of welded joints.A high wall shear stress(WsS)experimental setup was established to conduct the online electrochemical corrosion *** influence of WRH sizes on local corrosion of welded joints was studied at different flow *** electrochemical signals of the local corrosion of X80 welded joints at different flow rates were monitored in real time using electrochemical impedance spectroscopy and wire beam *** addition,the corrosion products composition and properties were *** results show that the micro-turbulent flow fields induced by the WRHs can enhance ion mass transfer near the welded *** corrosion products on the WRH surface also present different microscopic morphologies at different flow *** strong flow fields,the locally enhanced wsS can peel off the dense corrosion product partially,leading to the electrochemical distribution of large cathode and small anode,which accelerates the occurrence and development processes of the local corrosion of welded *** scientific guidelines for the corrosion protection of long-distance oil and gas pipelines can be potentially provided.

关键词： X80 steel welded joint Welding reinforcement height Micro-turbulence CO_(2)corrosion-Ion mass transfer

Fully distributed dynamic event-triggered formation-containment tracking for multiagent systems with multiple types of disturbances

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Science China(Information Sciences) 2024年第1期67卷 168-186页

作者： Weihua li Huaguang ZHANG Juan ZHANG rui WANG College of Information Science and Engineering Northeastern University State Key Laboratory of Synthetical Automation for Process Industries Northeastern University

This paper is dedicated to addressing the time-varying output formation-containment tracking(TVOFCT) problem for heterogeneous linear multiagent systems(MASs) with multiple types of disturbances under directed communication *** agents are divided into tracking leaders,formation leaders,and *** the output space,the formation leaders are required to form an expected geometric formation while tracking the tracking leader,and the followers are required to enter the convex hull spanned by formation ***,a disturbance observer is designed to observe the disturbance with deterministic ***,by combining adaptive technology with event-triggered technology,an independent fully distributed dynamic event-triggered(FDDET) compensator is designed to estimate the state of the tracking *** main advantages of this compensator lie in the following three aspects:(1) the adaptive weight does not increase unboundedly;(2) the interval time between events is expanded;(3) the design does not rely on any global *** to the design of this compensator,an independent FDDET convex hull observer is further designed to observe the convex hull spanned by formation ***,based on the designed disturbance observer,compensator,and convex hull observer,the adaptive disturbance rejection control input which can make the MASs achieve TVOFCT is ***,a numerical simulation is provided to clearly verify the validity of the theoretical results.

关键词： formation-containment tracking disturbance rejection multiagent systems fully distributed control dynamic event-triggered control

Effects of Different light Qualities on the Growth Characteristics of Populus trinervis

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Phyton-International Journal of Experimental Botany 2024年第5期93卷 1043-1056页

作者： Jiaqi li Zhensheng Qiao Dan zong Chengzhong He Key Laboratory for Forest Genetics and Tree Improvement and Propagation in Universities of Yunnan Province Southwest Forestry UniversityKunmingChina Key Laboratory of Biodiversity Conservation in Southwest China State Forestry AdministrationSouthwest Forestry UniversityKunmingChina Key Laboratory for Forestry Resources Conservation and Utilization in the Southwest Mountains of China Ministry of EducationSouthwest Forestry UniversityKunmingChina

Populus trinervis is native to China and plays an irreplaceable role in maintaining the ecological balance of boreal and temperate *** mainly grows in high-altitude *** present,there are limited studies on the response of *** to different light qualities,so it is necessary to investigate the photosynthetic physiological changes of *** in different light *** our study,*** was grown for 8 months under light filtered by three different colored *** three treatments were blue film,green film,and white plastic *** effects of blue(B),green(G),and white(W)light on photosynthetic pigment content,absolute growth,photosynthetic parameters,soluble sugar content,and chlorophyll fluorescence parameters were studied,*** to the Wtreatment,the chlorophyll a and b,carotenoids,total chlorophyll content(a+b),absolute growth of seedling height,net photosynthetic rate(PN),water use efficiency(WUE),total soluble sugars,sucrose,and nonphotochemical quenching(NPQ)of *** were significantly increased under B ***,chlorophyll a and b,carotenoids,total chlorophyll(a+b),transpiration rate(Tr),intercellular CO_(2) concentration(Ci),stomatal conductance(gs),absolute growth of seedling height and leaf length,reducing sugar,total soluble sugar content,and NPQ were significantly increased under G *** results showed that the absolute growth and chlorophyll content of *** were increased under B light,while the sugar and photosynthetic parameters were increased under G *** studies may look into how B light impacts absolute growth and promotional mechanisms,as well as how G light affects the accumulation of sugar levels.

关键词： Blue light green light white light photosynthetic pigment soluble sugar

The reaction mechanism and interfacial crystallization of Al nanoparticle-embedded Ni under shock loading

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Defence Technology（防务技术） 2024年第3期33卷 114-124页

作者： Yifan Xie Jian-li Shao rui liu Pengwan Chen State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081China Explosion Protection and Emergency Disposal Technology Engineering Research Center of the Ministry of Education Beijing100039China

The shock-induced reaction mechanism and characteristics of Ni/Al system,considering an Al nanoparticle-embedded Ni single crystal,are investigated through molecular dynamics *** the shock melting of Al nanoparticle,interfacial crystallization and dissolution are the main *** reaction degree of Al particle first increases linearly and then logarithmically with time driven by rapid mechanical mixing and following *** reaction rate increases with the decrease of particle diameter,however,the reaction is seriously hindered by interfacial crystallization when the diameter is lower than 9 nm in our ***,we found a negative exponential growth in the fraction of crystallized Al atoms,and the crystallinity of B2-NiAl(up to 20%)is positively correlated with the specific surface area of Al *** can be attributed to the formation mechanism of B2-NiAl by structural evolution of finite mixing layer near the collapsed *** shock melting of both Al particle and Ni matrix,the liquid-liquid phase inter-diffusion is the main reaction mechanism that can be enhanced by the formation of internal *** addition,the enhanced diffusion is manifested in the logarithmic growth law of mean square displacement,which results in an almost constant reaction rate similar to the mechanical mixing process.

关键词： Shock-induced reaction Molecular dynamics simulations Interfacial crystallization Reaction mechanism

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