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Large area crystalline Weyl semimetal with nano Au film based micro-fold line array for THz detector

science China(Technological sciences) 2023年第11期66卷 3267-3275页

作者： SONG Qi ZHOU Yu JIA ErSe WANG JiaTong ZHANG Min ZHANG BingYuan Shandong Key Laboratory of Optical Communication Science and Technology School of Physics Science and Information TechnologyLiaocheng UniversityLiaocheng 252059China North China Institute of Computing Technology Beijing 100083China Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province College of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhen 518060China School of Precision Instrument and Opto-electronics Engineering Tianjin UniversityTianjin 300072China

The advancement of 6G technology relies on the development of high-performance terahertz detectors that can operate at room *** detectors are crucial for Internet of Things(Io T)applications,which require sensitive environmental sensing and efficient reception of 6G *** significant research focus is on detection technology with high responsiveness and low equivalent noise power for 6G signals,which experience high losses in the *** meet the demand for ultra-sensitive detectors in 6G technology,we have employed several ***,we prepared a large area of Weyl-semimetal layer through magnetron ***,we obtained a high-quality Weyl-semimetal active layer by carefully controlling the annealing ***,a thin nano-Au layer was introduced as a micro-cavity reflection layer to enhance the device's detection ***,we incorporated an electromagnetic induction well to improve carrier confinement and enhance the detection *** proposed high-performance terahertz detector,with its potential for industrial production,offers a valuable technical solution for the advancement of 6G technology.

关键词： micro-cavity Weyl semimetal crystalline thin film THz device

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Thermal Management and Dynamic Performance of a Cooler Design for the Supercritical CO2 Turbine Shaft Cooling

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FRONTIERS IN ENERGY RESEARCH 2022年 10卷

作者： Li, Jun Gurgenci, Hal Guan, Zhiqiang Li, Jishun Xue, Yujun Li, Lun School of Mechatronics Engineering Henan University of Science and Technology Henan Key Laboratory for Machinery Design and Transmission System Henan University of Science and Technology Luoyang China School of Mechanical and Mining Engineering University of Queensland Brisbane QLD Australia

This paper presents the results of a numerical study on a supercritical CO2 (SCO2) turboshaft cooling device by considering heat transfer and hydrodynamics. A micro-cooling device with a radius clearance of 50 micron and a nozzle diameter of 4 mm was designed and used to investigate the heat transfer characteristics of a micro-spacing impinging and gas film dynamics. Sixteen nozzles (N = 16) are equally spaced around the shaft in single or double rows. Investigations include journal speed- and eccentricity-dependent forward and cross-coupled force coefficients, and the effects of nozzle layouts and mass flow rate on the heat transfer efficiency. Analysis of the correlation coefficient shows that the gas density in the radial clearance is the dominant factor affecting the convective heat transfer performance, while the fluid velocity is a secondary factor. And the cooling efficiency (mass flow utilization rate) at low cooling pressure (p(s) < 0.7 MPa) is significantly greater than that at high cooling pressure (p(s) > 0.7 MP). In addition, considering the structure alone, a dual-row cooler exhibits a higher average Nusselt number, also registers a higher mass flow rate at the same pressure. Once the shaft is heated only one end, the difference in effectiveness between single- and dual-row cooling is not significant, so coolers with a single-row configuration should be preferred. Then, experimental values for the temperature of the heated rotor are provided under specific cooling airflow conditions. Dynamic analysis results show that the force coefficient of the single-row configuration is more dependent on the journal rotation speed and eccentricity ratio, and exhibits a negative direct stiffness coefficient at higher inlet pressure and journal rotation speed. Moreover, cross-coupled terms (stiffness coefficient) generally have a more explicit variation tendency than direct terms, and are more sensitive to changes in shaft speed and eccentricity. Small clearance cool

关键词： shaft cooling gas film stiffness heat transfer cooler jet impingement

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Polarization extension yielding ultrahigh piezoelectric response in xPb(Nb_(2/3)Ni_(1/3))O_(3)-(1-x)Pb(Zr_(0.3)Ti_(0.7))O_(3)ferroelectrics ceramics

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Journal of Materials science & technology 2024年第22期189卷 37-43页

作者： Yongxing Wei Junlong Yan Siyuan Dong Changqing Jin Huawei Zhang Lin Hu Ruihua Nan Ling Gao Zhonghua Dai Zengzhe Xi Zengyun Jian Li Jin Shaanxi Key Laboratory of Optoelectronic Functional Materials and Devices School of Materials and Chemical EngineeringXi’an Technological UniversityXi’an 710021China Shaanxi Coal Chemical Industry Technology Research Institute Co.Ltd. Xi’an 710070China Shaanxi Province Key Laboratory of Thin Films Technology&Optical Test Xi’an Technological UniversityXi’an 710021China Electronic Materials Research Laboratory Key Laboratory of the Ministry of EducationSchool of Electronic Science and EngineeringFaculty of Electronic and Information EngineeringXi’an Jiaotong UniversityXi’an 710049China

The heightened piezoelectric performance observed in most explored perovskite systems is typically at-tributed to the electric-field-induced phase transition near the morphotropic phase boundary(MPB)or polymorphic phase boundary(PPB).This study,however,unveils a distinct piezoelectric enhancement mechanism in the xPb(Nb_(2/3)Ni_(1/3))O_(3)-(1-x)Pb(Zr_(0.3)Ti_(0.7))O_(3)(PNN-PZT)system,diverging from the MPB/PPB-centered piezoelectric ***,the composition with x=0.55,positioned close to the tetragonal-pseudocubic(T-PC)phase boundary,achieves an unprecedented piezoelectric coefficient(d_(33))of 1264 pC/N,while retaining a tetragonal local ***,on a local scale,electric fields do not in-cite phase transitions,suggesting that the exceptional piezoelectric performance in PNN-PZT stems from polarization extension near the T-PC *** from other mechanisms,the relative permittivity significantly increases post-poling due to this particular enhancement *** dielectric behavior in poled specimens does not exhibit a conspicuous change at the ferroelectric-relaxor transition ***,both the relative permittivity and planar electromechanical coupling coefficient experience a sharp rise in the temperature range of−25℃to 25℃.This investigation underscores the pivotal role of designing compositionally-driven T-PC phase boundaries,presenting a promising avenue for enhancing piezoelectric properties in ferroelectric ceramics.

关键词： Phase boundary Pseudocubic Polarization extension Local structure Piezoelectric effect

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Satellite observations of coastal upwelling in the northern Arafura Sea

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Journal of Oceanology and Limnology 2024年第2期42卷 361-376页

作者： Zheyuan YU Zhanjiu HAO Zhenhua XU Peiwen ZHANG Jia YOU Baoshu YIN Hongwei YANG College of Mathematics and System Science Shandong University of Science and TechnologyQingdao 266590China CAS Key Laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of SciencesQingdao 266071China Pilot National Laboratory for Marine Science and Technology(Qingdao) Qingdao 266237China Center for Ocean Mega-Science Chinese Academy of SciencesQingdao 266071China University of Chinese Academy of Sciences Beijing 100049China CAS Engineering Laboratory for Marine Ranching Institute of OceanologyChinese Academy of SciencesQingdao 266071China

Coastal upwelling is significant for marine ecosystems by lifting nutrient-rich deep waters into the euphotic zone,thereby increasing primary and secondary *** satellite observations show that the northern Arafura Sea(NAS),especially in the coastal region,features high chlorophyll-a(chl-a)concentrations,implying a strong coastal ***,coastal upwelling in the NAS has not received much *** on a semi-automatic image processing technology,the seasonal and interannual variability of coastal upwelling in the NAS are investigated in this study using satellite-observed sea surface temperature(SST)and wind *** results suggest that there are seasonal coastal upwelling events in the NAS modulated by upwelling-favorable southeast monsoon(SEM).The annual mean days,mean area,and annual mean intensity of coastal upwelling events during the SEM season are 92 days,6514 km^(2),and-5.31×10^(5),respectively,while the corresponding values during the northwest monsoon(NWM)season are 32 days,5569 km^(2),and-1.41×10^(5).It is also found that the SEM coastal upwelling in the NAS displays prominent interannual *** strong upwelling events are found in 2010,2013,2016,and 2017 when the southeast monsoon winds were *** analysis suggests that at the interannual scale,the upwelling index(UI)averaged in the SEM season is negatively correlated with that of three upwelling *** can be attributed to the limitation of onshore geostrophic flow which is evidenced by the negative correlation between the UI and the alongshore difference in sea surface *** study highlights the important role of the southeast monsoon in the temporal variability of coastal upwelling in the NAS.

关键词： coastal upwelling the northern Arafura Sea southeast monsoon interannual variability

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In-situ synthesized SiC/TiC/SiTiOC hybrid nanofiber mats for broad-range temperature microwave absorption

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science China Technological sciences 2025年第6期68卷 183-196页

作者： Yashan HUO Yuetong QIAN Minshan ZHAO Lei ZHANG Yujia TAN Zhihui HE Peng MIAO Fuchun ZHANG Wei CUI Renchao CHE School of Physics and Electronic Information Yan'an University Shaanxi Key Laboratory of Intelligent Processing for Big Energy Data Laboratory of Advanced Materials Shanghai Key Lab of Molecular Catalysis and Innovative Materials Academy for Engineering &Technology Advanced Coatings Research Center of Ministry of Education of China Fudan University School of Materials and Chemical Engineering Xi'an Technological University School of Materials Science & Engineering Tongji University College of Physics Donghua University

Efficient, temperature-insensitive electromagnetic attenuation materials are critical for high microwave absorption at high temperatures. This study presents SiC/TiC/SiTiOC hybrid nanofiber mats constructed using an in-situ synthesis method;these mats incorporate SiC/TiC as the microwave loss unit and SiTiOC as the antioxidant unit, offering an innovative approach to high-temperature microwave absorption. The introduction of high-conductivity TiC not only optimizes the dielectric constant and impedance matching of the material but also enhances its thermal cycling stability. This design ensures steady electromagnetic attenuation, enabling the hybrid nanofiber mats to maintain robust absorption performance in the X-band, even at high temperatures. At 873 K, the material demonstrates an effective absorption bandwidth of 3.6 GHz and a minimum reflection loss of-45.55 dB. Compared to single-system absorbers, such as SiC/C nanofiber materials, with a single system, the multicomponent SiC/TiC/SiTiOC hybrid nanofiber mats deliver reliable absorption performance in the temperature range of 293–873 K. This study confirms that highly conductive titanium-based ceramic materials used for dielectric property regulation effectively address the challenges of poor temperature stability and limited reusability in high-temperature carbon-ceramic absorbing materials, providing valuable insights and guidance for designing efficient microwave absorbers that can operate across a wide temperature range.

关键词： electrospinning SiC/TiC/SiTiOC hybrid nanofiber mats high-temperature microwave absorption dielectric properties thermal stability

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Toxicological responses of A549 and HCE-T cells exposed to fine particulate matter at the air–liquid interface

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Environmental science and Pollution Research 2024年第18期31卷 27375-27387页

作者： Chen, Wankang Ge, Pengxiang Deng, Minjun Liu, Xiaoming Lu, Zhenyu Yan, Zhansheng Chen, Mindong Wang, Junfeng Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control Collaborative Innovation Center of Atmospheric Environment and Equipment Technology School of Environmental Science and Engineering Nanjing University of Information Science & ampTechnology Nanjing210044 China Ningxia Meteorological Service Center Yinchuan750002 China

Fine particulate matter (PM2.5) can enter the human body in various ways and have adverse effects on human health. Human lungs and eyes are exposed to the air for a long time and are the first to be exposed to PM2.5. The "liquid immersion exposure method" has some limitations that prevent it from fully reflecting the toxic effects of particulate matter on the human body. In this study, the collected PM2.5 samples were chemically analyzed. An air–liquid interface (ALI) model with a high correlation to the in vivo environment was established based on human lung epithelial cells (A549) and immortalized human corneal epithelial cells (HCE-T). The VITROCELL Cloud 12 system was used to distribute PM2.5 on the cells evenly. After exposure for 6 h and 24 h, cell viability, apoptosis rate, reactive oxygen species (ROS) level, expression of inflammatory factors, and deoxyribonucleic acid (DNA) damage were measured. The results demonstrated significant dose- and time-dependent effects of PM2.5 on cell viability, cell apoptosis, ROS generation, and DNA damage at the ALI, while the inflammatory factors showed dose-dependent effects only. It should be noted that even short exposure to low doses of PM2.5 can cause cell DNA double-strand breaks and increased expression of γ-H2AX, indicating significant genotoxicity of PM2.5. Increased abundance of ROS in cells plays a crucial role in the cytotoxicity induced by PM2.5 exposure These findings emphasize the significant cellular damage and genotoxicity that may result from short-term exposure to low levels of PM2.5. © The Author(s) 2024.

关键词： Cell death

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Towards more reliable evaluation in pedestrian detection by rethinking“ignore regions”

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Visual Intelligence 2024年第1期2卷 39-51页

作者： Gang Li Xiang Li Shanshan Zhang Jian Yang Key Laboratory of Intelligent Perception and Systems for High-Dimensional Information of Ministry of Education School of Computer Science and EngineeringNanjing University of Science and TechnologyNanjingChina Jiangsu Key Laboratory of Image and Video Understanding for Social Safety School of Computer Science and EngineeringNanjing University of Science and TechnologyNanjingChina VCIP Nankai UniversityTianjingChina

It remains a challenging task to detect pedestrians in crowds and it needs more efforts to understand why the detectors *** we perform an error analysis based on the traditional evaluation strategy,we find that it produces many misleading false positives,which in fact cover occluded *** reason for this is that we usually have two kinds of annotations in the dataset:regular pedestrians(detection targets)labeled by full-body boxes and ignored pedestrians(NOT detection targets)labeled by visible *** pedestrians are labeled as an additional category termed the“ignore region”.Nevertheless,our detectors always predict a full-body box for each *** gap results in the following case:when a detector successfully predicts a full-body box for those ignored pedestrians,a false positive is triggered due to the low overlap between the predicted full-body box and the labeled visible box for the ignored *** becomes even more harmful as the detector improves and becomes more capable of locating occluded *** alleviate this issue,we devise a new pedestrian detection pipeline,which considers the additional visible box at both the detection and evaluation *** detection,we predict an extra visible box apart from the full-body box for every instance;during evaluation,we employ visible boxes instead of full-body boxes to match the“ignore region”.We apply the new pipeline to dozens of detection methods and validate the effectiveness of our pipeline in reducing the over-reporting of false positives and providing more reliable evaluation results.

关键词： Pedestrian detection Object detection Occlusion handling Evaluation metric

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Container-based data-intensive application scheduling in hybrid cloud-edge collaborative environment

Container-based data-intensive application scheduling in hyb...

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作者： Tang, Bing Luo, Jincheng Zhang, Jiaming School of Computer Science and Engineering Hunan University of Science and Technology Hunan Xiangtan China Hunan Key Laboratory for Service Computing and Novel Software Technology Hunan University of Science and Technology Hunan Xiangtan China School of Information and Communication Engineering Guangzhou Maritime University Guangdong Guangzhou China School of Information Engineering Wuhan University of Technology Hubei Wuhan China

Container virtualization technology represented by Docker has been widely used in the industry due to its advantages of lightweight, fast deployment, and easy portability. It can bring convenience to system deployment, operation, and maintenance. This article considers the implementation of AI-based IoT applications based on Docker and container technology in a cloud-edge collaborative environment. Three typical data-intensive applications, preprocessing, training, and inference in machine learning, are deployed using Docker containers. For these three types of tasks, this article proposes a container-based data-intensive application scheduling framework. Using an attribute-based data-driven method, a new scheduling approach considering multiple weighting factors is proposed, which is called DICS-OPT. The cloud nodes and edge nodes are scored and sorted uniformly. The container is scheduled to the node with the highest score, and then the task data is transmitted to the node to execute the task. NSGA-III-based genetic algorithm has been proposed to search for the optimal weighting factors. This article introduces the implementation of the prototype system and builds a cloud-edge collaborative testbed consisting of Raspberry Pis and PCs. The performance evaluation results indicates that the proposed scheduling approach outperforms existing approaches. Compared with existing approaches, DICS-OPT improves the average edge resource utilization by 10.05% to 69.04%, and saves the cloud resource cost by 16.02% to 36.68%. © 2023 John Wiley & Sons Ltd.

关键词： Edge computing

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An H∞ Load Frequency Control Scheme for Multi-Area Power system Under Cyber-Attacks and Time-Varying Delays

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IEEE Transactions on Power systems 2023年第2期38卷 1336-1349页

作者： Zhang, Guangdou Li, Jian Bamisile, Olusola Xing, Yankai Cai, Dongsheng Huang, Qi University of Electronic Science and Technology of China Power System Wide-Area Measurement and Control Sichuan Province Key Laboratory School of Mechanical and Electrical Engineering Sichuan Chengdu610056 China Chengdu University of Technology College of Nuclear Technology and Automation Engineering Sichuan611400 China

In the power system, the application of the signals transmitted from the sensors to the controller can significantly improve the dynamic performance. However, cyber-attacks and time delays exist widely in the communication network, which has a considerable effect on stability, operation, and control. In this paper, an ${{\boldsymbol{H}}_\infty }$ load frequency control (LFC) scheme for multi-area power systems under cyber-attacks and time-varying delays is investigated. First, false data injection attacks (FDIA), as well as denial of service (DoS) attacks, are viewed as two typical cyber-attacks and introduced into the multi-area power system. Then, the state-space equations of the LFC power system under these two attacks and time-varying delays are analyzed and modeled. Furthermore, by using Lyapunov stability theory and linear matrix inequality (LMI) method, an ${{\boldsymbol{H}}_\infty }$ LFC scheme for attacked and delayed power systems is developed. The purpose of the proposed controller is to guarantee the closed-loop system exponentially mean-square stable with prescribed ${{\boldsymbol{H}}_\infty }$ performance. Finally, a three-area LFC system is employed to demonstrate the effectiveness of the proposed mechanism. The simulation results verified that the control performance of an attacked and delayed system can be improved significantly via the designed controller. © 1969-2012 IEEE.

关键词： Controllers

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Lake Water Storage and Long-Term Variation of Nganga Rinco on the Tibetan Plateau Revealed by ICESat-2 and Satellite Imagery

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IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing 2025年 18卷 12915-12924页

作者： Li, Yunmei Chen, Qianqian Zhang, Shiqiang Cui, Yuanzheng Huang, Chang Northwest University Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity College of Urban and Environmental Sciences Xi'an710127 China Anhui Normal University Engineering Technology Research Center of Resources Environment and Geographic Information System of Anhui Province School of Geography and Tourism Wuhu241002 China GEOVIS Earth Technology Company Ltd. Hefei230093 China Nanjing Institute of Geography and Limnology Chinese Academy of Sciences State Key Laboratory of Lake and Watershed Science for Water Security Nanjing210008 China

Lake storage in Nganga Rinco serves as a crucial indicator of climate change and is significant for the ecological environment. This study combines ICESat-2, the Global Surface Water dataset, and geographic interpolation to derive lake bathymetry and assess 30-year water storage variation of Nganga Rinco. Bathymetry in dynamic regions offers higher spatial resolution and more precise elevation data compared to the SRTM DEM. When compared to in situ bathymetry, the derived bathymetry showed an average error of 3.64 m, with errors concentrated in deeper regions. The underwater elevation of Nganga Rinco ranges from 4 628.18 to 4 718.87 m, with an average of 4 698.62 m, showing a total depth variation of 90.69 m. The lake's volume grew from 11.23 km3 in 1992 to 12.06 km3 in 2021, peaking at 12.16 km3 in 2020, reflecting an overall fluctuation increase of 0.82 km3 (7%). Gray relation analysis was applied to examine how water storage responds to climate change factors. The analysis revealed that precipitation significantly impacts water storage capacity, while air temperature indirectly affects storage changes through snow/ice melting and evapotranspiration. This research offers valuable insights into lake storage estimation in regions that have no direct underwater terrain measurements, providing important implications for water resource management and advancing our understanding of climate change impacts on high-altitude lakes. © 2008-2012 IEEE.

关键词： Bathymetry

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