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Observation and analysis of positive leader re-illumination in a 10 m ultra-high voltage transmission line gap under switching impulse voltages

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Plasma Science and Technology 2024年第10期26卷 93-100页

作者： Biao huang Xuan ZHOU She WANG Chijie Zhuang rong zeng Le DENG Eliet Engineering School Changsha University of Science&TechnologyChangsha 410114People’s Republic of China State Key Laboratory of Disaster Prevention&Reduction for Power Grid Changsha University of Science&TechnologyChangsha 410114People’s Republic of China China International Engineering Consulting Co. Ltd.Beijing 100048People’s Republic of China Department of Electrical Engineering Tsinghua UniversityBeijing 100084People’s Republic of China

The leader propagation is one of the most important stages in long air gap *** mechanism behind leader re-illumination remains *** high humidity conditions(20.0–30.1 g/m^(3)),we have conducted experiments of long sparks in a 10 m ultra-high voltage(UHV)transmission line gap under switching impulse *** positive leaders predominantly propagate discontinuously,with almost no significantly continuous propagation *** leader channels are intensely luminous and each elongation segment is straight,with streamers resembling the“branch type”which differs from the“diffuse type”streamers at the front of continuous propagation *** distribution of the propagation velocities is highly random(3.7–18.4 cm/μs),and the average velocity(9.2 cm/μs)significantly exceeds that of continuous propagation(1.5–2.0 cm/μs).Analysis suggests that the current-velocity models suitable for continuous leader propagation do not align well with the experimental data in re-illumination *** on the discharge current waveforms and optical images,it is speculated that the newly elongated leader in re-illumination mode does not evolve gradually from the stem(about 1 cm)but rather evolves overall from a thermal channel much longer than stem.

关键词： long air gap discharge positive leader re-illumination discontinuous leader propagation

Research of simulation and experiment on arc characteristics of gas mechanical switch

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High Voltage 2024年第3期9卷 626-635页

作者： Cheng Jiang Lu Qu Zhangqing Yu Zhizheng Gan Xin yan rong zeng Yulong huang Shaofu Li Department of Electrical Engineering Tsinghua UniversityBeijingChina School of Information Engineering Southwest University of Science and TechnologyMianyangChina Sichuan Energy Internet Research Institute Tsinghua UniversityChengduChina

An arc is the high-temperature discharge plasma produced in the opening process of mechanical switches,which directly affects the breaking capability of a hybrid DC circuit *** to the physical mechanism of an electric arc,the construction of an arc model for simulation analysis is an important technical means in the electrical *** this study,based on the theory of magneto hydrodynamics(MHD),a gas mechanical switch model of a natural commutation DC circuit breaker with a compound gap is *** arc motion process under different conditions is simulated and *** influence of different initial pressures,different opening speeds,and different striking currents on the arc voltage characteristics is *** results show that the larger the gas pressure,the smaller the arc volume and the higher the arc *** faster the opening speed,the longer the arc and the higher the arc voltage;with the increase of the current,the arc voltage increases rapidly at a low current,while the arc voltage increases slowly at a high current.

关键词： characteristics striking slowly

Making waste profitable: Efficient recovery of metallic iron from jarosite residues

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Chinese Journal of Chemical Engineering 2024年第7期71卷 66-76页

作者： Songshan Zhou Yunhui Han rong huang Yin huang Qingyuan Dong Haiyin Gang Jinchuan Qin Xi Yu Xiangfei zeng Wenxing Cao Jiqin Wang Shaoqin Chen rong Wang Mengjun Chen Key Laboratory of Solid Waste Treatment and Resource Recycle(SWUST) Ministry of EducationSouthwest University of Science and TechnologyMianyang 621010China School of Environment Key Laboratory of Yellow River and Huai River Water Environment and Pollution ControlMinistry of EducationHenan Normal UniversityXinxiang 453007China School of National Defense Science and Technology College SWUST Ministry of EducationSouthwest University of Science and TechnologyMianyang 621010China

To address the hazardous by-product of zinc smelting and resource utilization of jarosite residue,this study applies an electric field-assisted hot acid treatment to completely recycle iron(Fe).This innovative approach aims to enhance the leaching efficiency of Fe from jarosite *** introduction of an electric field changes the charge distribution on the surface of the particles to enhance ions and electrons exchange and promotes the collision between particles to strengthen reaction *** on the above,the leaching efficiency of Fe in jarosite under sulfuric acid attack has improved *** result shows that Fe leaching efficiency reaches 98.83%,which is increased by 28%under the optimal experimental conditions:current density of 30 mA·cm^(-2),H_(2)SO_(4) concentration of 1.5 mol·L^(-1),solid-liquid ratio of 70 g·L^(-1),temperature of 80℃ and time of 12 *** kinetics calculations show that the apparent activation energy is 16.97 kJ·mol^(-1) and the leaching of jarosite residue is controlled by a mixture of chemical reaction and diffusion,as well as the temperature and concentration of the leaching solution have an influence on *** work provides a feasible idea for the efficient leaching of Fe from jarosite residue.

关键词： Jarosite residue Electric filed Leaching kinetics

MOF and its derivative materials modified lithium-sulfur battery separator:a new means to improve performance

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Rare Metals 2024年第6期43卷 2418-2443页

作者： rong-Wei huang Yong-Qi Wang Dan You Wen-Hao Yang Bin-Nan Deng Fei Wang Yue-Jin zeng Yi-Yong Zhang Xue Li National Local Joint Engineering Research Center for Lithium-Ion Batteries and Materials Preparation Technology Key Laboratory of Advanced Batteries Materials of Yunnan ProvinceFaculty of Metallurgical and Energy EngineeringKunming University of Science and TechnologyKunming 650093China State Key Laboratory of Physical Chemistry of Solid Surfaces Collaborative Innovation Centre of Chemistry for Energy MaterialsState-Province Joint Engineering Laboratory of Power Source Technology for New Energy VehicleEngineering Research Center of Electrochemical TechnologyMinistry of EducationCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China

In recent years,lithium-sulfur batteries(LSBs)are considered as one of the most promising new generation energies with the advantages of high theoretical speeific capacity of sulfur(1675 mAh·g^(-1)),abundant sulfur resources,and environmental friendliness storage technologies,and they are receiving wide attention from the ***,the problems of the shuttle effect and lithium dendrite growth in LSBs have limited their practical application,so there is a need to find ways to solve these *** is an excellent choice to use novel materials to modify battery *** those novel materials,the metal-organic framework(MOF)has the properties of regular pores and controllable *** applied as a positive electrode and diaphragm,it can restrain the shuttle effect and lithium dendrite growth,especially since it shows excellent performance in diaphragm ***,various design strategies and synthesis methods of MOF-modified separators are reviewed in this paper,and the applications of MOF in LSBs separators in different forms are introduced,including the composite of MOF and carbon-based materials,the compounding of MOF and polymer,self-carbonization to form MOF-derived *** the same time,different characterization techniques are systematically reviewed to obtain the physical and chemical properties of MOF particles and the working mechanism of MOF-modified diaphragm,which provides a basis for further research in this ***,some future research trends and directions are put forward to fully tap the future commercial potential of MOF-modified diaphragm in LSBs.

关键词： MOF Lithium-sulfur battery Modified diaphragms Design strategies Prospect Characterization

Effects of formal credit on pastoral household expense: Evidence from the Qinghai-Xizang Plateau of China

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Journal of Integrative Agriculture 2024年第5期23卷 1774-1785页

作者： Yan Zhang Yi huang Fan Zhang zeng Tang State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems College of Pastoral Agriculture Science and TechnologyLanzhou UniversityLanzhou 730020China

Formal credit is critical in agricultural production,allowing more expenditure and productive input,thereby improving farmers'*** pastoral China,formal financial institutions are gradually ***,a limited understanding remains of how formal credit affects herders'household *** on a survey of 544 herders from the Qinghai-Xizang Plateau of China,this study adopted the propensity score matching approach to identify the effect of formal credit on herders'total household expenses,daily expenses,and productive *** results found that average age,grassland mortgage,and other variables significantly affected herders'participation in formal *** credit could significantly improve household expenses,especially productive expenses.A heterogeneity analysis showed that formal credit had a greater impact on the household total expense for those at higher levels of wealth;however,it significantly affected the productive expense of herders at lower wealth ***,the mediating effect indicated that formal credit could affect herders'household income,thus influencing their household ***,this study suggests that policies should improve herders'accessibility to formal credit.

关键词： formal credit herders expense Qinghai-Xizang Plateau

Printed Biosensors for the Detection of Alzheimer’s Disease Based on Blood Biomarkers

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Journal of Analysis and Testing 2024年第2期8卷 133-142页

作者： Yu zeng Zhen huang Yibiao Liu Tailin Xu Longgang Central Hospital of Shenzhen Shenzhen518116China School of Biomedical Engineering Shenzhen UniversityShenzhen518060China

Alzheimer’s disease(AD)is a chronic neurodegenerative disorder,and early diagnosis plays a crucial role in its prevention and *** recent years,blood-based biomarkers for early AD diagnosis have gained attention due to their non-invasiveness and minimal adverse reactions,which make them an attractive *** the onset of the COVID-19 pandemic,visiting large medical examination centers for blood tests has become increasingly *** trend is shifting towards community or home-based sampling,which relies on the development and application of portable,miniaturized,and highly sensitive *** the various sensors used for detecting blood biomarkers in AD,printed sensors demonstrate great potential in AD blood biomarker detection due to their ease of miniaturization,scalability for mass production,and compatibility with various detection *** this review,we focus on discussing the application of printed sensors in the analysis of blood biomarkers for *** also explore the challenges faced by printed sensors in early diagnosis based on AD blood biomarkers and propose potential solutions to address these challenges.

关键词： Printed biosensors Alzheimer’s disease Blood biomarkers Printing technology

A Federated Learning Framework with Blockchain-Based Auditable Participant Selection

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Computers, Materials & Continua 2024年第6期79卷 5125-5142页

作者： huang zeng Mingtian Zhang Tengfei Liu Anjia Yang College of Cyber Security Jinan UniversityGuangzhou510632China

Federated learning is an important distributed model training technique in Internet of Things(IoT),in which participant selection is a key component that plays a role in improving training efficiency and model *** module enables a central server to select a subset of participants to performmodel training based on data and device *** doing so,selected participants are rewarded and actively perform model training,while participants that are detrimental to training efficiency and model accuracy are ***,in practice,participants may suspect that the central server may have miscalculated and thus not made the selection *** lack of trustworthiness problem,which can demotivate participants,has received little *** problem that has received little attention is the leakage of participants’private information during the selection *** will therefore propose a federated learning framework with auditable participant *** supports smart contracts in selecting a set of suitable participants based on their training loss without compromising the *** the possibility of malicious campaigning and impersonation of participants,the framework employs commitment schemes and zero-knowledge proofs to counteract these malicious ***,we analyze the security of the framework and conduct a series of experiments to demonstrate that the framework can effectively improve the efficiency of federated learning.

关键词： Federated learning internet of things participant selection blockchain auditability privacy

Urban Flood Mitigation Strategies with Coupled Gray–Green Measures: A Case Study in Guangzhou City, China

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International Journal of Disaster Risk Science 2024年第3期15卷 467-479页

作者： Jiayue Li Jiajun zeng Guoru huang Wenjie Chen School of Civil Engineering and Transportation South China University of Technology School of Architecture South China University of Technology State Key Laboratory of Subtropical Building and Urban Science South China University of Technology College of Water Conservancy and Civil Engineering South China Agricultural University

The integration of gray and green infrastructure has proven to be a feasible approach for managing stormwater in established urban areas. However, evaluating the specific contributions of such coupled strategies is challenging. This study introduced a novel integrated hydrological-hydrodynamic model that takes into account the layout of low-impact development(LID)facilities along with pipeline alignment and rehabilitation. Reliable results from modeling were used to assess the individual contribution of LID and improved drainage facilities to urban flooding mitigation. We selected a natural island in Guangzhou City, China, as the study site. The results indicate that combining three LID measures, namely green roofs, sunken green spaces, and permeable pavements, can reduce total runoff by 41.7% to 25.89% for rainfall recurrence periods ranging from 1year to 100 years, and decrease the volume of nodal overflow by nearly half during rainfall events of less than 10-year return period. By integrating LID measures with the upgraded gray infrastructure, the regional pipeline overloading condition is substantially alleviated, resulting in a significant improvement in pipeline system resilience. For urban flooding control, it is recommended to integrate sufficient green space and avoid pipe-laying structural issues during urban planning and construction. The findings may assist stakeholders in developing strategies to best utilize gray and green infrastructure in mitigating the negative eff ects of urban flooding.

关键词： Coupled hydrodynamic model Gray–green approach Guangzhou City LID Pipe renovation Urban inundation

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超声测距中的伪随机码渡越时间的捕获

传感技术学报 2006年第3期19卷 843-846页

作者：黄增荣秦会斌黄博志杭州电子科技大学CAE研究所杭州310018

采用数字相关的方法确定超声波测距中的渡越时间。借助于一个经过适当选择的伪随机序列信号作为超声波的发射信号,可以通过数字相关方法求出发射序列和接收序列的相位差,即渡越时间。本文在计算自相关函数时放弃了快速傅立叶变换(FFT)算... 详细信息

采用数字相关的方法确定超声波测距中的渡越时间。借助于一个经过适当选择的伪随机序列信号作为超声波的发射信号,可以通过数字相关方法求出发射序列和接收序列的相位差,即渡越时间。本文在计算自相关函数时放弃了快速傅立叶变换(FFT)算法,省去了乘法运算,取而代之的是只用异或和加法的并行数字相关技术,它显著地减少了数据处理时间和FPGA资源。系统以Altera公司的quartusⅡ为开发平台,经逻辑综合、布局布线后,适配到FPGA芯片中,给出了仿真结果。

关键词：超声测距渡越时间数字相关器 VHDL语言