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The fabrication and characterization of 4H-SiC power UMOSFETs

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Chinese Physics B 2013年第2期22卷 426-428页

作者：宋庆文张玉明韩吉胜 Philip Tanner sima Dimitrijev 张义门汤晓燕郭辉 School of Technical Physics Xidian University Key Laboratory of Wide Band Gap Semiconductor Materials and Devices Xidian University Queensland Micro and Nanotechnology Center Griffith University Griffith School of Engineering Griffith University

The fabrication of 4H-SiC vertical trench-gate metal-oxide-semiconductor field-effect transistors（UMOSFETs） is reported in this *** device has a 15-μm thick drift layer with 3×10^15 cm^-3 N-type doping concentration and a 3.1μm channel *** measured on-state source-drain current density is 65.4 A/cm^2 at Vg = 40 V and VDS = 15 *** measured threshold voltage（Vth） is 5.5 V by linear extrapolation from the transfer characteristics.A specific on-resistance（Rsp-on） is 181 mΩ·cm^2 at Vg = 40 V and a blocking voltage（BV） is 880 V（IDS = 100 μA@880V） at Vg = 0 V.

关键词： UMOSFETs 4H-SiC specific on-resistance blocking voltage

Flashover Characteristics of Flat Plate Model Under DC Voltage in Wind-sand Condition

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高电压技术 2008年第12期34卷 2570-2574页

作者： sima Wen-xia MA Gao-quan YANG Qing State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing University Chongqing 400044 China

The influence of sand dust on discharge of external insulation has caused widespread *** present,the research results show wind-sand electricity has a remarkable effect on the discharge characteristics of insulator and has little influence on the discharge characteristics of air *** flashover of insulator strings occurs along the insulator surface and air gaps,and the sand dust deposited on the insulator surface may affect the flashover characteristics of insulator *** paper studies the flashover characteristics of flat plate model under DC voltage in wind-sand *** experimental results show that under positive polarity voltage,the flashover voltage of the flat plate model has a maximum value,while under negative polarity voltage,the flashover voltage of the flat plate model has a minimum value with a certain degree of sand dust *** wind or sand in sand-dust weather has an important effect on the flashover characteristics of the flat plate *** certain variation range of electric charge,electric charge of sand dust has little effect on the flashover voltage of flat plate model under DC *** deposition of sand has significant influence on the flashover process of flat plate model,which is related to the deposition density and moisture content of sand particle.

关键词：风沙条件平板模型直流电放电特性

Mini-CEX在脊柱外科住院医师规范化培训中的应用

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继续医学教育 2024年第2期38卷 77-80页

作者：张晗祥王翀司马金埕陈星覃建朴遵义医科大学附属医院骨科贵州遵义563000

目的探讨迷你临床演练评估(mini-clinical evaluation exercise,Mini-CEX)教学模式在脊柱外科住院医师规范化培训中的应用。方法选取2021年6月至2022年6月在脊柱外科轮转的住院医师规范化培训学员,分为试验组和对照组。对照组通过传统... 详细信息

目的探讨迷你临床演练评估(mini-clinical evaluation exercise,Mini-CEX)教学模式在脊柱外科住院医师规范化培训中的应用。方法选取2021年6月至2022年6月在脊柱外科轮转的住院医师规范化培训学员,分为试验组和对照组。对照组通过传统模式进行教学活动,试验组第1个月接受传统模式教学,第2个月开始每周接受Mini-CEX教学评价,并由带教老师现场反馈不足。2个月学习结束后,2组学员均参加出科考试,并对2组学员进行Mini-CEX教学评价,分别比较2组学员出科考试成绩及Mini-CEX教学评价分数。结果经过2个月的学习,试验组与对照组出科考试成绩(理论考试与操作考试)差异无统计学意义(P>0.05);试验组末次成绩优于初次成绩,差异有统计学意义(P0.05);在体格检查、人文关怀、沟通技巧、临床综合能力4个方面,试验组成绩优于对照组,差异有统计学意义(P<0.05);在最终总成绩上,试验组也优于对照组,差异有统计学意义(P<0.001)。结论Mini-CEX教学模式可以提高脊柱外科住培医师的临床能力。

关键词： Mini-CEX 教学模式脊柱外科住培医师传统教学出科考试

Time series modeling of animal bites

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Journal of Acute Disease 2023年第3期12卷 121-128页

作者： Fatemeh Rostampour sima Masoudi Department of Biostatistics and Epidemiology Faculty of MedicineUrmia University of Medical SciencesUrmiaIran

Objective:To explore the modeling of time series of animal bite occurrence in northwest ***:In this study,we analyzed surveillance time series data for animal bite cases in the northwest Iran province of Iran from 2011 to *** used decomposition methods to explore seasonality and long-term trends and applied the Autoregressive Integrated Moving Average(ARIMA)model to fit a univariate time series of animal bite *** ARIMA modeling process involved selecting the time series,transforming the series,selecting the appropriate model,estimating parameters,and ***:Our results using the Box Jenkins model showed a significant seasonal trend and an overall increase in animal bite incidents during the study *** best-fitting model for the available data was a seasonal ARIMA model with drift in the form of ARIMA(2,0,0)(1,1,1).This model can be used to forecast the frequency of animal attacks in northwest Iran over the next two years,suggesting that the incidence of animal attacks in the region would continue to increase during this time frame(2018-2019).Conclusion:Our findings suggest that time series analysis is a useful method for investigating animal bite cases and predicting future *** existence of a seasonal trend in animal bites can also aid in planning healthcare services during different seasons of the ***,our study highlights the importance of implementing proactive measures to address the growing issue of animal bites in Iran.

关键词： Animal bites Time series analysis ARIMA modeling Box Jenkins model Northwest Iran

Combination Operation for Neutral Point of 35 kV Power Grids in Mountainous Area

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高电压技术 2008年第12期34卷 2626-2630页

作者： YUAN Tao sima Wen-xia RAN Rui ZHU Wei State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing University Chongqing 400044 China Linan Electric Power Bureau Linan 311307 China

Based on a lot of measurement and analysis,this paper find that the unbalanced nature of 35 kV grids due to unsymmetrical capacitance values gives difficulty in neutral point operation in mountainous *** compensation of Petersen coil can rectify imbalance of voltage but bring up new problem that Petersen coil can not extinguish grounding arc effectively in *** put down contradiction mentioned above,this paper proposes a combination operation for neutral point of 35 kV grids as neutral point insulated in routine operation and grounding through Petersen coil in fault,then EMTP simulation is carried *** indicates that new neutral operation method can improve lightning withstand level and decrease trip-out rate of grids.

关键词：山区补偿电网消弧线圈投切运行暂态分析

Experimental Analysis on Shielding Effect of the Grounding Electrodes Under Impulse-current

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高电压技术 2008年第12期34卷 2609-2614页

作者： YANG Cai-wei sima Wen-xia YUAN Tao YANG Qing State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing University Chongqing 400044 China

Generally,the flow of a lightning impulse current from a grounding electrode into ground is a very complicated process determined by many *** order to analyze the mechanism of the impulse current dissipating in the earth from grounding electrode,the experiments that had been carried out by other authors almost used a single horizontal grounding wire or vertical grounding rod for sake of ***,in practical conditions,most of the grounding systems are constructed of grounding electrodes with branches in different *** this study,basing on the principle of dimensional similarity,impulse simulation experiments are performed on the common ground electrodes with conductor *** paper focuses on analyzing the impulse current dispersal regularity of different branches when injecting at one *** with the leakage current distribution of a single ground electrode,it is found that the leakage currents along the branches increase with the distance to the current feed point,and the more conductors near the injection point,the more uneven the leakage current distribution *** work indicates that shielding effect should be taken into account when analyzing the impulse characteristics of grounding electrodes.

关键词：屏蔽效应接地电极冲击电流试验研究

Pion, Kaon and Antiproton Production in Pb+PbCollisions at LHC Energy √s NN=2.76 TeV: A Model-Based Analysis

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Journal of Modern Physics 2015年第2期6卷 111-120页

作者： Pradeepta Guptaroy sima Guptaroy Department of Physics Raghunathpur College Raghunathpur India Department of Physics Basantidevi College Kolkata India

Large Hadron Collider (LHC) had produced a vast amount of high precision data for high energy heavy ion collision. We attempt here to study i) transverse momenta spectra, ii) K/π, P/π ratio behaviours, iii) rapidity distribution, and iv) the nuclear modification factors of the pion, kaon and antiproton produced in P+P and Pb+Pb collisions at energy √s NN=2.76 TeV, on the basis of Sequential Chain Model (SCM). Comparisons of the model-based results with the measured data on these observables are generally found to be modestly satisfactory.

关键词： Relativistic Heavy Ion Collisions Baryon Production Light Mesons

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两种环锯脊柱骨组织活检的比较

中国矫形外科杂志 2024年第17期32卷 1618-1621页

作者：季文军宋浩司马金埕叶盛李进马亚萍张顶梅王信遵义医科大学附属医院骨科贵州遵义563000

[目的]探讨两种环锯在脊柱骨组织活检中的应用效果。[方法]回顾性分析2020年1月—2023年8月96例脊柱骨组织活检患者的临床资料,根据术前医患沟通结果,50例采用内螺纹环锯活检(内螺纹组),另外46例采用普通环锯活检(普通组)。比较两组患... 详细信息

[目的]探讨两种环锯在脊柱骨组织活检中的应用效果。[方法]回顾性分析2020年1月—2023年8月96例脊柱骨组织活检患者的临床资料,根据术前医患沟通结果,50例采用内螺纹环锯活检(内螺纹组),另外46例采用普通环锯活检(普通组)。比较两组患者围手术期相关指标、检测结果及术后不良反应。[结果]两组活检节段、切口长度、术中出血量、活检成功率的差异均无统计学意义(P>0.05),内螺纹组手术时间[(17.0±2.8)min vs(19.5±3.0)min,P<0.001]显著少于普通组、获取组织阳性率显著高于普通组(87.8%vs 64.5%,P<0.001)、术后并发症的总发生率显著低于普通组(20.0%vs 54.4%,P<0.001)。[结论]使用内螺纹环锯可明显缩短椎体活检时间,提高穿刺活检阳性率,降低术后并发症发生率。

关键词：骨组织活检内螺纹环锯普通环锯手术时间活检阳性率

Investigation of Inlet Gas Streams Effect on the Modified Claus Reaction Furnace

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Advances in Chemical Engineering and Science 2013年第3期3卷 6-14页

作者： Reza Rezazadeh sima Rezvantalab Department of Chemical Engineering Urmia University of Technology Urmia Iran

The objective of this paper is to model the main reactions that take place in the Claus reactor furnace and compare it with actual data and simulated process. Since the most important point is the selection of suitable reaction conditions to increase the reactor performance, the model is formulated to predict the performance of the Claus plant. To substantiate the theoretical model, we used actual process condition and feed composition in Shahid Hasheminejad Gas Refinery. Model equations have been solved by using MATLAB program. Results from MATLAB are compared with those from SULSIM? simulator and with actual plant data. The AAD (Average Absolute Deviation) of modeling results with actual data is 2.07% and AAD of simulation results with real data is 4.77%. Error values are very little and show accuracy and precision of modeling and simulation. The predicting curve for different parameters of the reactor furnace according to variable conditions and specifications are given.

关键词： Claus Process Hydrogen Sulfide Modeling Reactor Furnace