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Comprehensive CM Filter Design to Suppress Conducted EMI for SiC-JFET Motor Drives
Xun Gong,Ivan Josifovic,J.A. Ferreira 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5
This paper proposes a comprehensive EMI common-mode (CM) filter design procedure to suppress conducted EMI in silicon carbide (SiC) JFETs based inverter-fed motor drive systems. The first part of this paper is focusing on analyzing the EMC issue arisen from the newly generated power semiconductor device - SiC JFET, where the switching dynamics of SiC JFET and Si IGBT with the same power flowing level are compared. Then the second part towards EMI suppression for the inverter prototype. A comprehensive EMI CM filter design procedure is proposed. The proposed CM equivalent circuit model is able to evaluate the filter insertion loss gains over the whole conducted EMI frequency range, thereby different filter topologies can be compared and optimally selected. The performed experiments form the guideline that exhibits the process how the generated conducted EMI from the built inverter prototype is successfully suppressed to comply with the IEC61800-3 standard step by step.
Quantitative Evaluation Index for Analysis of Assembly Effect on Shield Tunnel Segment Structures
Xun Liu,Kun Feng,Chuan He,Haihua Zhang 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.9
The local force and deformation of shield tunnel will be transferred and redistributed owing to the discontinuous segmental structure. This study develops quantitative evaluation index to explore the influence of the axial compression ratio, eccentricity, and longitudinal force on the assembly effect. A full-scale test is conducted on a single segment and staggered assembled segmental linings. First, the results show that the assembly effect has an obvious redistribution influence on the force and deformation of the segment. Second, the influence of eccentricity on the bending moment is much larger than that of the axial force. The stiffness between rings varied at different positions and the larger the stiffness difference, the more obvious the assembly effect. The results demonstrate that the design and mechanical performance of the shield tunnel under different embedded conditions can be optimized by increasing the longitudinal force, which moderates the assembly effect and ensures the structure reaches the highest bearing capacity.
Xun-an Ning,Chongyang Yang,Yujie Wang,Zuoyi Yang,Jingyu Wang,Ruijing Li 한국생물공학회 2014 Biotechnology and Bioprocess Engineering Vol.19 No.4
A strict aerobic Acinetobacter baumanniiYNWH 226, isolated from an activated sludge reactortreating textile wastewater, was able to grow on Congo redas the sole carbon source under aerobic conditions. Thedecolorization and TOC reduction efficiency were 99.1 and93.72%, respectively. The effects of the Congo redconcentration were studied. The environmental factors (i.e.,pH, temperature and agitation speed) on the biodegradationof Congo red in aqueous phase were studied and evaluatedusing response surface methodology. The results indicatedthat when the Congo red concentration was 100 mg/L, theoptimal decolorization conditions were as follows: 37°C,pH 7.0 and 180 rpm. The single A. baumannii YNWH 226was able to form aromatic amines by reductive breakage ofthe azo bond and then oxidize them into non-toxicmetabolites.
Xun Fang,Ahmad Yar Qamar,신상태,조종기 한국임상수의학회 2019 한국임상수의학회지 Vol.36 No.5
The objective of this study was to analyse the effects of MS-275 (Class I and II histone deacetylase inhibitor) supplementation on the development of porcine in-vitro somatic nuclear transfer embryo production. During in-vitro development, early embryos were exposed to different concentrations of MS-275 (0, 5 μM, 10 μM, and 20 μM). In in-vitro culture supplemented group, the blastocyst development rate was significantly enhanced by 10 μM concentration than other groups (24.0% vs. 19.3%, 21.8%, 11.5%; P < 0.05). Additionally, the 6 h supplementation group, significantly improved the blastocysts production than 24 h, 48 h and control groups (26.1% vs. 17.0%, 15.2%, 2.8%; P < 0.05). Following supplementation with optimal concentrations and time (10 μM-6 h group), the blastocyst production was significantly higher than control (25.7% vs 15.8%; P < 0.05). The optimal concentrations of MS-275 significantly enhanced the percentages of ICM:TE than control (43.6% vs. 38.4%; P < 0.05) accompanied with significantly higher expression levels of reprogramming related genes (POU5F1, Naong, and SOX2). In conclusion, the optimal concentrations of 10 μM MS-275 and 6 h supplementation during in-vitro culture can significantly improve the quality of porcine in-vitro somatic nuclear transfer embryos through histone acetylation and epigenetic modification. Increasing the efficiency of clonal animal production will greatly promote the development of animal disease models and xenotransplantation.
Xun Sun,김현수,양승덕,김철규,윤준용 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.6
Butterfly valves are used widely as flow controllers in many industrial applications. In order to design and select an appropriate valvefor a particular application, it is important to predict correctly its flow coefficient. The flow coefficient of a valve can be affected by anumber of factors. This study presents a numerical investigation of the effect of friction on the flow coefficient of a triple eccentric butterflyvalve with various valve opening degrees. Since the Reynolds number and cavitation can affect the flow coefficient under certainconditions, these effects are discussed and analyzed based on previously reported experimental data before studying the effects of friction. Under the test conditions recommended in IEC 60534-2-3, it is found that the effects of the Reynolds number and cavitation are quitesmall and can be ignored. The flow coefficients obtained from numerical simulations that take into account friction are found to be ingood agreement with the experimentally determined ones. The differences in the flow coefficients obtained from numerical simulationsthat consider friction and those that ignore it are discussed. There is a maximum difference of 17 % for a fully open valve. The resultsshow that increases in the roughness height significantly increase the frictional pressure drop. The effect of the roughness height on thefrictional pressure drop and total pressure drop can be fitted well using fitting functions for fixed opening degree. It is found that the effectof the roughness can cause the determined flow coefficient to be different from the actual value. Thus, the measured flow coefficientsand pressure drops for such valves can be determined with accuracy through experimental techniques and numerical simulationsthat account for the effect of roughness.
( Xun Jin ),( Jongweon Kim ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.7
In this paper, we propose a robust blind watermarking scheme for high-definition video. In the embedding process, luminance component of each frame is transformed by 2-dimensional fast Fourier transform (2D FFT). A secret key is used to generate a matrix of random numbers for the security of watermark information. The matrix is transformed by inverse steerable pyramid transform (SPT). We embed the watermark into the low and mid-frequency of 2D FFT coefficients with the transformed matrix. In the extraction process, the 2D FFT coefficients of each frame and the transformed matrix are transformed by SPT respectively, to produce two oriented sub-bands. We extract the watermark from each frame by cross-correlating two oriented sub-bands. If a video is degraded by some attacks, the watermarks of frames contain some errors. Thus, we use an ensemble position-based error correcting algorithm to estimate the errors and correct them. The experimental results show that the proposed watermarking algorithm is imperceptible and moreover is robust against various attacks. After embedding 64 bits of watermark into each frame, the average peak signal-to-noise ratio between original frames and embedded frames is 45.7 dB.
Neural-Network-Based Vehicle Torque Demand Forecasting
Xun Shen,Tielong Shen 제어로봇시스템학회 2017 제어로봇시스템학회 국제학술대회 논문집 Vol.2017 No.10
A multiple-step vehicle torque demand forecasting problem is investigated in this paper. Neural network method is applied to forecast toque demand in the future five steps based on the measurements of vehicle speed and torque demand in the past three steps. Neural networks for forecasting are trained based on history drive cycles’ data and used to do multiple-step forecasting in another drive cycle to verify the performance. Results of the application have shown that the desired goal has been successfully achieved.
Design and Implementation of an ONS Test-bed
Xun, Lu,Piao, Chunjie,Hongryul Yoon,Park, Sangwee,Choung, Jaeuk 대구대학교 정보통신연구소 2004 情報通信硏究 Vol.3 No.1
This paper presents a design and implementation of an ONS test-bed. It provides EPC naming and Web services with respect to EPCTM code currently under standardization. The goal of this research is to investigate the feasibility and complexity of the EPC network. The prototype can be used to verify the concept of the EPC network by providing experimental setup for domestic researchers and engineers.