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基于SiC器件的高压宽范围直流辅助电源

电工技术学报 2025年第3期40卷 786-799页

作者：王议锋车超昌陈博白昱张向前天津大学电气自动化与信息工程学院天津300072 天津恩特能源科技有限公司天津300100 天津电气科学研究院有限公司天津300180

辅助电源是电力变换装置中的重要组成部分,在太阳能发电站等系统中,需应对高压宽范围输入下的稳定运行挑战。针对单管反激电源在高压宽范围输入导致的高电压应力、高成本以及低效率问题,该文基于级联反激变换器,首先进行了开关模态分析... 详细信息

辅助电源是电力变换装置中的重要组成部分,在太阳能发电站等系统中,需应对高压宽范围输入下的稳定运行挑战。针对单管反激电源在高压宽范围输入导致的高电压应力、高成本以及低效率问题,该文基于级联反激变换器,首先进行了开关模态分析,深入研究计及寄生参数的开关工作过程;然后在此基础上,建立级联反激变换器的精确数学模型,研究了各核心元器件对电路性能的影响,并提出一种参数设计方法;最后基于SiC器件,搭建了一台300~1 500V输入、24 V输出的100 W辅助电源样机,变换器全工况运行中最高效率达到93.4%。结果验证了所设计的高压宽范围辅助电源方案的有效性。在低成本、宽输入范围和高电压应力条件下,保证了辅助电源的高效转换。

关键词： SiC 高压辅助电源反激变换器

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基于山嵛酸和ZIF-8改性的超疏水防结冰棉织物

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纺织学报 2025年第2期46卷 197-206页

作者：袁华彬王沂沨王家朋向永翾陈国强邢铁玲苏州大学纺织与服装工程学院江苏苏州215006

为解决棉织物因结冰导致的保暖性能下降和人体热损失加剧的问题,利用生物质材料山嵛酸和沸石咪唑酯骨架材料(ZIF-8)对棉织物进行改性,制备出具有超疏水和防结冰性能的山嵛酸/ZIF-8改性棉织物。通过扫描电子显微镜、傅里叶红外光谱以及X... 详细信息

为解决棉织物因结冰导致的保暖性能下降和人体热损失加剧的问题,利用生物质材料山嵛酸和沸石咪唑酯骨架材料(ZIF-8)对棉织物进行改性,制备出具有超疏水和防结冰性能的山嵛酸/ZIF-8改性棉织物。通过扫描电子显微镜、傅里叶红外光谱以及X射线光电子能谱对改性棉织物的表面形貌和化学结构进行分析,并对其浸润性、稳定性和防结冰性能进行表征。结果显示:改性后棉织物表面具有独特的纳米花状结构,接触角高达160.6°,滑动角仅为2°,展现出优异的自清洁和防沾污性能;山嵛酸/ZIF-8改性棉织物还表现出卓越的物理和化学稳定性,能够承受600 min的连续水洗和20次砂纸磨损,并在100℃高温、-20℃低温、强碱、强酸及有机溶剂等极端环境下长期保持稳定;该改性棉织物在-15℃和-20℃环境中延缓结冰时间分别为713.2 s和351.6 s,表现出优异的防结冰性能。此方法不仅拓宽了ZIF-8和生物质材料在纺织品上的应用空间,还为开发防结冰纺织品提供了新思路。

关键词：山嵛酸沸石咪唑酯骨架材料棉织物超疏水自清洁防沾污防结冰

Current Status and Development Tendency of Wearable Cardiac Health Monitoring

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Chinese Journal of Electrical Engineering 2023年第1期9卷 71-92页

作者： yifeng wang Zheng Zhao Jiangtao Li School of Electrical Engineering Xi’an Jiaotong UniversityXi’an 710049China

Wearable cardiac monitoring devices can provide uninterrupted monitoring of cardiac activities over a long period of *** have developed rapidly in recent years in terms of convenience,comfort,and *** by the development of sensor and materials technology,big data and artificial intelligence,wearable cardiac monitoring can become a crucial basis for novel medical models in the ***,the basic concepts and representative devices of wearable cardiac monitoring are first ***,its core technologies and the latest representative research progress in physiology signal sensing,signal quality enhancement,and signal reliability are systematically ***,an insight and outlook on the future development trends and challenges of wearable cardiac monitoring are discussed.

关键词： Wearable cardiac monitoring electrocardiogram seismocardiography photoplethysmogram cardiovascular disease

Smart monitoring of underground railway by local energy generation

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Underground Space 2017年第4期2卷 210-219页

作者： Mingyuan Gao Jun Lu yifeng wang Ping wang Li wang School of Ciuil Engineering Southwest Jiaotong UniversityChengduChina Key Laboratory of High-speed Railway Engineering Ministry of EducationChengduChina Department of Structural Engineering Delft University of TechnologyDelfNetherlands

The objective of this study is to develop a prototype for smart monitoring of underground rail transit by local energy *** technology contributes to powering rail-side devices in off-grid and remote *** paper presents the principles,modeling,and exper-imental testing of the proposed system that includes two subsystems:(1)an electromagnetic energy generator with DC-DC boost con-verter(2)a rail-borne wireless sensor node with embedded accelerometers and temperature/humidity sensors and(3)a data processing algorithm based on the Littlewood-Paley(L-P)*** testing results,power consumption,L-P wavelet transform methods,and feasibility analysis are *** application scenario is described:the electromagnetic energy harvester together with the DC-DC boost converter is used as a local energy source for powering the sensor nodes of a Wireless Sensor Network(WSN),and the abnormal signals of out-of-round wheels are identified based on the measured rail acceleration signals and L-P wavelet analysis.

关键词： Condition monitoring Energy harvesting Electromagnetic Underground rail transit Wavelet

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车丝机旋转刀架分析及故障的快速判断

机械工程与自动化 2025年第1期54卷 220-221页

作者：王轶峰吴水康赵威宝钢股份钢管条钢事业部上海201900

Colinet公司的MPM-T20液压旋转刀架集机、电、液于一体,动力驱动由液压旋转马达和液压缸来完成,而位置控制由光电开关、CNC(数控)控制系统以及机械编码盘来实现,其换刀动作主要包括松开、分度旋转、预定位、精定位以及锁紧5个动作。主... 详细信息

Colinet公司的MPM-T20液压旋转刀架集机、电、液于一体,动力驱动由液压旋转马达和液压缸来完成,而位置控制由光电开关、CNC(数控)控制系统以及机械编码盘来实现,其换刀动作主要包括松开、分度旋转、预定位、精定位以及锁紧5个动作。主要分析了此刀架的工作原理,并针对此刀架使用过程中经常发生的刀架旋转无法定位的现象,制定了简易、快速的故障判断方法。

关键词：车丝机旋转刀架定位故障判断

Forecasting method of monthly wind power generation based on climate model and long short-term memory neural network

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Global Energy Interconnection 2020年第6期3卷 571-576页

作者： Rui Yin Dengxuan Li yifeng wang Weidong Chen State Grid Hebei Electric Power Company Shijiazhuang 050022P.R.China China Electric Power Research Institute Nanjing 210003P.R.China

Predicting wind power gen eration over the medium and long term is helpful for dispatchi ng departme nts,as it aids in constructing generation plans and electricity market *** study presents a monthly wind power gen eration forecast!ng method based on a climate model and long short-term memory(LSTM)n eural n etwork.A non linear mappi ng model is established between the meteorological elements and wind power monthly utilization *** considering the meteorological data(as predicted for the future)and new installed capacity planning,the monthly wind power gen eration forecast results are output.A case study shows the effectiveness of the prediction method.

关键词： Wind power Monthly generation forecast Climate model LSTM neural network

Fluorescent Double Network Hydrogels with Ionic Responsiveness and High Mechanical Properties for Visual Detection

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Journal of Wuhan University of Technology(Materials Science) 2024年第2期39卷 487-496页

作者：郑湾 LIU Lerong Lü Hanlin wang Yuhang LI Feihu ZHANG Yixuan 陈艳军 wang yifeng School of Materials Science and Engineering Wuhan University of TechnologyWuhan 430070China

We developed a fluorescent double network hydrogel with ionic responsiveness and high mechanical properties for visual *** nanocomposite hydrogel of laponite and polyacrylamide serves as the first network,while the ionic cross-linked hydrogel of terbium ions and sodium alginate serves as the second *** double-network structure,the introduction of nanoparticles and the reversible ionic crosslinked interactions confer high mechanical properties to the *** ions are not only used as the ionic cross-linked points,but also used as green emitters to endow hydrogels with fluorescent *** the basis of the “antenna effect” of terbium ions and the ion exchange interaction,the fluorescence of the hydrogels can make selective responses to various ions(such as organic acid radical ions,transition metal ions) in aqueous solutions,which enables a convenient strategy for visual detection toward ***,the fluorescent double network hydrogel fabricated in this study is promising for use in the field of visual sensor detection.

关键词： visual detection ionic responsiveness fluorescent hydrogels double network hydrogels mechanical property

Empirical Thermal Investigation of Oil-Immersed Distribution Transformer under Various Loading Conditions

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Computer Modeling in Engineering & Sciences 2021年第11期129卷 829-847页

作者： Syed Ali Raza Ahsan Ullah Shuang He yifeng wang Jiangtao Li School of Electrical Engineering Xi’an Jiaotong UniversityXi’an710049China

The distribution transformer is the mainstay of the power *** internal temperature study is desirable for its safe operation in the power *** purpose of the present study is to determine direct comprehensive thermal distribution in the distribution transformers for different loading *** achieve this goal,the temperature distribution in the oil,core,and windings are studied at each *** experimental study is performed with a 10/0.38 kV,10 kVA oil–immersed transformer equipped with forty–two PT100 sensors(PTs)for temperature measurement installed inside during its manufacturing *** possible locations for the hottest spot temperature(HST)are considered that made by finite element analysis(FEA)simulation and losses calculations.A resistive load is made to achieve 80%to 120%loading of the test transformer for this *** temperature is measured in each part of the transformer at all provided loading *** is observed that temperature varies with loading throughout the transformer,and a detailed map of temperature is obtained in the whole test *** these results,the HST stays in the critical section of the primary winding at all loading *** work is helpful to understand the complete internal temperature layout and the location of the HST in distribution transformers.

关键词： Distribution transformer direct temperature measurement sensor location loading conditions hottest spot temperature thermal distribution

Relationship between structure and aboveground biomass of typical steppe and climate in Inner Mongolia

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Journal of Environmental Sciences 1990年第4期2卷 19-30页

作者： wang yifeng Institute of Botany,Academia Sinica,Beijing 100044,China

Typical steppe in Inner Mongolia belongs to a part of Central Asia sub-region in Eurasian temperate steppe region. In climate distinct wet and dry season, coherence of water and heat result in single peak type of seasonal dynamic of steppe biomass. Community biomass has linear regressional equation with community height, its correlation coefficient (R) is 0.959***. Growth rate of biomass in June, July and August is usually at 1.5-3.0 g/m2. d-1. Community standing dead occurs in June and equates green living biomass by mid-September. Community biomass is only standing dead biomass in the mid-October. Biomass, green production and standing dead have linear regressional relation with days of plant growing, their correlation coefficient (R) are 0.9919***, 0.9878*** and 0.9923***, respectively. Yearly dynamic of typical steppe biomass is variable, the maximum value is 2.4 times as much as the minimum. The peak biomass of Stipa grandis steppe was 87g/m2 in dry 1980 and 210g/m2 in rainy 1981, and their height and coverage were 60cm and 30% in 1980, 95cm and 40% in 1981. Major population biomass and individual plant dry weight at the peak time in 1980 is 50-70% lower than in 1981. In 1980, grass over the layer of 40 cm high became dead and community standing dead biomass amounted to 32.07% of the total production, 2.5 times as much as that in 1981 (13.08%). In addition, growth rate of biomass before the peak time in 1980 were negative value for 2 times. Seasonal dynamic curve of dry matter content is in negative proportion to biomass increase and dry matter content is higher in dry 1980 than in rainy 1981.

关键词： aboveground biomass typical steppe Inner Mongolia.