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Online Monitoring Method for Junction Temperature of SiC MOSFETs based on Temperature Sensitive Electrical Parameter

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CSEE Journal of Power and Energy Systems 2024年第4期10卷 1799-1807页

作者： Han Cao Puqi Ning Yunhao Huang Xuhui Wen Wuhan second Ship design and research institute Wuhan 430205China Key Laboratory of Power Electronics and Electric Drive Institute of Electrical EngineeringChinese Academy of SciencesBeijing 100190China institute of Electrical engineering Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Collaborative Innovation Center of Electric Vehicles in beijing Beijing 100081China

Compared to Si devices,the junction temperature of SiC devices is more critical due to the reliability concern introduced by immature packaging technology applied to new *** paper proposes a practical SiC MOSFET junction temperature monitoring method based on the on-state voltage$\\boldsymbol{V}_{\\mathbf{ds}(\\mathbf{on})}$*** Section II of the paper,the temperature sensitivity of the on-state voltage$\\boldsymbol{V}_{\\mathbf{ds}(\\mathbf{on})}$is *** hardware of the measurement system is set up in Section III,which consists of an On-state Voltage Measurement Circuit(OVMC),the sampling and isolation ***,a calibration method based on the self-heating of the SiC MOSFET chip is presented in Section *** the final Section,the junction temperature is monitored synchronously according to the calibration *** proposed method is applied to a Buck converter and verified by both an Infrared Radiation(IR)camera and a Finite Element Analysis(FEA)tool.

关键词： Junction temperature Silicon Carbide(SiC)MOSFET TSEP

The Experimental Investigations of Dielectric Barrier Discharge and Pulse Corona Discharge in Air Cleaning

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Plasma Science and Technology 2003年第5期5卷 1961-1964页

作者：左莉侯立安杨林松 engineering design&research institute of the second artillery corps.beijing 100011 China Anti Chemical institute Beijing 102205China

The dielectric barrier discharge (DBD) and pulse corona discharge(PCD) plasma generator was used to remove NH3, H2S, C7H8 etc. from atmosphere. The principle and characteristic of the two ways was discussed in the art... 详细信息

关键词： low temperature plasma dielectric barrier discharge pulse corona discharge air cleaning

Prediction and validation of diffusive uptake rates for indoor volatile organic compounds in axial passive samplers

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Energy and Built Environment 2024年第1期5卷 24-31页

作者： Yan Wang Tao Yu Jinhan Mo Department of Building Science Tsinghua UniversityBeijing 100084China beijing Key Laboratory of Indoor Air Quality Evaluation and Control Beijing 100084China Wuhan second Ship design and research institute Wuhan 430205China School of Energy and Power engineering Beihang UniversityBeijing 100191China Key Laboratory of Eco Planning&Green Building Ministry of Education(Tsinghua University)Beijing 100084China

The diffusive uptake rate is essential for using passive samplers to measure indoor volatile organic compounds(VOCs).The traditional theoretical model of passive samplers requires available regression formulas of uptake rates and physicochemical properties of adsorbents to predict the uptake ***,it is difficult to obtain the uptake rates of different VOCs under different sampling periods,and it is also difficult to obtain the physical parameters of adsorbents accurately and *** study provides a reliable numerical prediction method of diffusive uptake rates of *** modeling was based on the standard automated thermal desorption(ATD)tubes packed with Tenax TA and the mass transfer process during *** experimental determinations of toluene uptake rate are carried out to verify the prediction *** uptake rates of typical indoor VOCs are obtained from the literature to calibrate the key apparent parameters in the model by statistical regression *** predicted model can provide the VOC diffusive uptake rates under different sampling duration with an average deviation of less than 5%.This study can provide the basis for fast and accurate prediction of diffusive uptake rates for various VOC pollutants in built environments.

关键词： Indoor air quality Diffusive uptake rate Prediction model Sampling Adsorption

Preparation and characterization of in-site regenerated TiO_2-ACFs photocatalyst

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International Journal of Minerals,Metallurgy and Materials 2011年第3期18卷 357-363页

作者： Rong Yang Jian-hua Liu Song-mei Li engineering design ＆ research institute of the second artillery corps Beijing 100011 China School of Materials Science and engineering Beihang University Beijing 100083 China

In-site regenerated titanium dioxide-activated carbon fibers （TiO2-ACFs） photocatalyst was prepared by the sol-gel method. De-tailed surface and structural characterization of the TiO2-ACFs photocatalyst was carried out. The photoactivity of TiO2-ACFs under ultra-violet irradiation was compared with original ACFs and pure TiO2 by the degradation of methylene blue aqueous solution. The degradation efficiency by the TiO2 （5wt%）-ACFs sample is much higher than that by TiO2 and ACFs. The results show that the photocatalysis by TiO2-ACFs is a six-step process. The adsorption-transfer-photocatalysis rate of TiO2-ACFs is higher than the adsorption-photocatalysis rate of TiO2, so the photocatalysis rate of the TiO2-ACFs system is higher than that of TiO2 photocatalyst.

关键词： photocatalysts photocatalysis microstructure titanium dioxide activated carbon fibers

Saddlepoint Approximation Method in Reliability Analysis:A Review

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Computer Modeling in engineering & Sciences 2024年第6期139卷 2329-2359页

作者： Debiao Meng Yipeng Guo Yihe Xu Shiyuan Yang Yongqiang Guo Lidong Pan Xinkai Guo School ofMechanical and Electrical engineering University of Electronic Science and Technology of ChinaChengdu611731China institute of Electronic and Information engineering of UESTC in Guangdong Dongguan523808China Glasgow College University of Electronic Science and Technology of ChinaChengdu611731China beijing research institute of Mechanical&Electrical Technology Ltd.Beijing100083China

The escalating need for reliability analysis(RA)and reliability-based design optimization(RBDO)within engineering challenges has prompted the advancement of saddlepoint approximationmethods(SAM)tailored for such *** article offers a detailed overview of the general SAM and summarizes the method characteristics ***,recent enhancements in the SAM theoretical framework are ***,the mean value first-order saddlepoint approximation(MVFOSA)bears resemblance to the conceptual framework of the mean value second-order saddlepoint approximation(MVSOSA);the latter serves as an auxiliary approach to the *** distinction is rooted in the varying expansion orders of the performance function as implemented through the Taylor *** the saddlepoint approximation and third-moment(SATM)and saddlepoint approximation and fourth-moment(SAFM)strategies model the cumulant generating function(CGF)by leveraging the initial random moments of the *** their optimal application domains diverge,each method consistently ensures superior relative precision,enhanced efficiency,and sustained *** method elucidated is exemplified through pertinent RA or RBDO *** juxtaposing them against alternative strategies,the efficacy of these methods becomes *** outcomes proffered are subsequently employed as a foundation for contemplating prospective theoretical and practical research endeavors concerning *** main purpose and value of this article is to review the SAM and reliability-related issues,which can provide some reference and inspiration for future research scholars in this field.

关键词： Reliability analysis reliability-based design optimization saddlepoint approximation

Phase field modeling of grain stability of nanocrystalline alloys by explicitly incorporating mismatch strain

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Rare Metals 2024年第7期43卷 3370-3382页

作者： Min Zhou Hong-Hui Wu Yuan Wu Hui Wang Xiong-Jun Liu Sui-He Jiang Xiao-Bin Zhang Zhao-Ping Lu beijing Advanced Innovation Center for Materials Genome engineering State Key Laboratory for Advanced Metals and MaterialsUniversity of Science and Technology BeijingBeijing 100083Cnina institute for Carbon Neutrality University of Science and TechnologyBeijing 100083China institute of Materials Intelligent Technology Liaoning Academy of MaterialsShenyang 110004China

Ab st ra ct Nanocrystalline materials exhibit unique properties due to their extremely high grain boundary(GB) ***,this high-density characteristic induces grain coarsening at elevated temperatures,thereby limiting the widespread application of nanocrystalline *** experimental observations revealed that GB segregation and second-phase pinning effectively hinder GB migration,thereby improving the stability of nanocry stalline *** this study,a mouified phase-field model that integrates mismatch strain,solute segregation and precipitation was developed to evaluate the influence of lattice misfit on the thermal stability of nanocrystalline *** simulation results indicated that introducing a suitable mismatch strain can effectively enhance the microstructural stability of nanocrystalline *** synergizing precipitation with an appropriate lattice misfit,the formation of second-phase particles in the bulk grains can be suppressed,thereby facilitating solute segregation/precipitation at the *** concentrated solute segregation and precipitation at the GBs effectively hinders grain migration,thereby preventing grain *** findings provide a new perspective on the design and regulation of nanocrystalline alloys with enhanced thermal stability.

关键词： Phase field model Mismatch strain second-phase precipitation Grain boundary segregation Nanocrystalline alloys

SAR regional all-azimuth observation orbit design for target 3D reconstruction

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Journal of Systems engineering and Electronics 2024年第3期35卷 609-618页

作者： WANG Yanan ZHOU Chaowei LIU Aifang MAO Qin beijing institute of Tracking and Communication Technology Beijing 100094China Nanjing research institute of Electronics Technology Nanjing 210012China Shanghai Aerospace Electronic Technology institute Shanghai 201109China

Three-dimensional(3D) synthetic aperture radar(SAR)extends the conventional 2D images into 3D features by several acquisitions in different aspects. Compared with 3D techniques via multiple observations in elevation, e.g. SAR interferometry(InSAR) and SAR tomography(TomoSAR), holographic SAR can retrieve 3D structure by observations in azimuth. This paper focuses on designing a novel type of orbit to achieve SAR regional all-azimuth observation(AAO) for embedded targets detection and holographic 3D reconstruction. The ground tracks of the AAO orbit separate the earth surface into grids. Target in these grids can be accessed with an azimuth angle span of360°, which is similar to the flight path of airborne circular SAR(CSAR). Inspired from the successive coverage orbits of optical sensors, several optimizations are made in the proposed method to ensure favorable grazing angles, the performance of 3D reconstruction, and long-term supervision for SAR sensors. Simulation experiments show the regional AAO can be completed within five hours. In addition, a second AAO of the same area can be duplicated in two days. Finally, an airborne SAR data process result is presented to illustrate the significance of AAO in 3D reconstruction.

关键词： synthetic aperture radar(SAR) orbit design all-azimuth observation(AAO) three-dimensional(3D)reconstruction successive coverage

Understanding the cooperative effects in the catalysis of homodimeric fluoroacetate dehalogenase

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Science China Chemistry 2024年第7期67卷 2382-2391页

作者： Ke-Wei Chen Jia-Nan Chen Jun Zhang Chao Wang Tian-Yu Sun Yun-Dong Wu Key Laboratory of Computational Chemistry and Drug design State Key Laboratory of Chemical OncogenomicSchool of Chemical Biology and BiotechnologyPeking University Shenzhen Graduate SchoolShenzhen 518055China institute of Chemical Biology Shenzhen Bay LaboratoryShenzhen 518132China College of Chemistry and Molecular engineering Peking UniversityBeijing 100871China Changping Laboratory Beijing 102200China

Fluoroacetate dehalogenases(FAcD),a homodimeric enzyme,catalyzes the conversion of fluoroacetic acid to glycolic acid(GoA).It has been proved that the enzyme has a half-of-the-site ***,its catalytic(C)subunit converts the first substrate to a covalent intermediate;then,the non-catalytic(NC)subunit binds a second substrate and promotes the conversion of the intermediate in the C subunit into the final *** the release of the product,the C subunit becomes the NC subunit,and the previous NC subunit becomes the C *** elucidate the detailed mechanism behind this cooperative catalysis,we have conducted microsecond-scale MD simulations along the reaction *** simulations indicate that the substrate in the NC subunit induces W185 and Y141 adopting an open conformation in the C *** opening of W185(C)facilitates the entry of catalytic water,enhancing the catalytic activity for product formation,while the opening of Y141(C)creates an unfavorable environment for product binding,promoting its *** interaction network analysis reveals that the substrate in the NC subunit can induce conformational changes through a conserved water chain at the interface.

关键词： enzyme catalysis molecular dynamics cooperative effect pre-reaction state

Experimental Study on Common and Steel Fiber Reinforced Concrete Under Dynamic Tensile Stress

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Journal of beijing institute of Technology 2004年第3期13卷 254-259页

作者：董新龙陈江瑛高培正祁振林王永忠王永刚王礼立 Mechanics and Materials Science research Center Ningbo University Ningbo Zhejiang315211 China research institute of engineering design The Second Artillery Corps of PLA Beijing100011 China

Split Hopkinson technique has been developed to test the strength of common concrete and steel fiber reinforced concrete under dynamic tensile stress. Two types of test methods are considered, the splitting tensile test and a modified spalling test in which a specimen is loaded under uniaxial stress. The result shows that the dynamic strength enhancement of concrete is remarkable by using the reinforcing fiber. But for the common concrete, the base of compressive strength seems to show little effect on the tensile strength under dynamic loading. The experimental results also show that the resistance to tensile fracture of the steel fiber reinforced concrete for C100-mix is higher than those of C40-mix..

关键词： concrete dynamic test tensile strength spalling