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Numerical simulations on atmospheric stability conditions and urban airflow at five climate zones in China

能源与人工环境(英文) 2021年第2期2卷 188-203页

作者： Guoxing Chen Li Rong guoqiang zhang Department of Engineering Aarhus UniversityInge Lehmanns Gade 10DK-8000 Aarhus CDenmark

Due to the quick development of urbanization,it is important to provide a healthy urban environment for the *** studies have obtained valuable conclusions of how to improve the urban airflow distribution under isothermal *** to adopt and interpret those conclusions when considering the solar-induced atmospheric stability conditions have not been clarified *** this study,the characteristics of atmospheric stability condition and influence of diurnal varying solar-induced thermal effect on urban airflow inside the idealized building arrays were investigated at five cities located at five climate zones in *** energy model,CitySim,was employed to simulate the annual distribution of solar-induced walls’temperatures inside the idealized building *** diurnal varying wall temperatures at the hottest days were set as thermal boundary conditions in computational fluid dynamic(CFD)*** albedo value of 0.5,the possibility of adopting the results from isothermal condition directly ranged from 7%to 11%for the five cities in China throughout the *** unstable condition ocuppied from 19%to 24%annually and the stable condition of more than 40%annually was *** the diurnal varying solar-induced thermal effect,the spatially-averaged air speeds and airflow patterns were significantly different from the isothermal *** percent of Richardson number under different atmospheric stability conditions annually based on the Citysim simulation results indicated that the atmospheric stability was most likely determined by the local climate characteristics and albedo value rather than the building layouts at the five selected cities in China,but this should be further investigated when the shadow effects of surrounding buildings were considered in simulations.

关键词： Urban airflow Solar-induced thermal boundary conditions Atmospheric stability CitySim CFD

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Saliency-Based Position Sensorless Control Methods for PMSM Drives-a Review

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Chinese Journal of Electrical Engineering 2017年第2期3卷 14-23页

作者： guoqiang zhang Gaolin Wang Dianguo Xu College of Electrical Engineering Harbin Institute of TechnologyHarbinChina

Permanent magnet synchronous motor(PMSM)drives are finding expanded use for industrial and domestic drive *** the distinguished characteristics such as reduced cost and increased reliability and robustness,position sensorless(self-sensing)control techniques have been good candidates for reliable and costless PMSM *** saliency-tracking based techniques further bring the expansion of applications with the extended controllable sensorless operating speed *** paper presents a review on state of the art techniques for position sensorless drives using the saliency-tracking based *** signal injection methods and the future scope of research including the dynamic bandwidth improvement and the acoustic noise reduction are discussed.

关键词： Permanent magnet synchronous motor(PMSM) sensorlesss saliency-tracking high-frequency(HF)signal injection

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基于X线片的全髋关节置换术前预测髋臼杯假体型号的新方法及其应用

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中华骨与关节外科杂志 2024年第10期17卷 873-878页

作者：陈宝刚冀全博任鹏倪明任其逢张国强河南省第二人民医院骨科郑州451100 中国人民解放军总医院第一医学中心骨科北京100853 山东大学齐鲁医院德州医院关节外科山东德州253000

目的:介绍一种基于X线片的全髋关节置换术(THA)前预测髋臼杯假体型号的新方法。方法:选择2021年6月至2022年3月于中国人民解放军总医院第一医学中心行THA的86例股骨头坏死患者进行回顾性分析。测量所有患者术前标准骨盆正位X线片上的骨... 详细信息

目的:介绍一种基于X线片的全髋关节置换术(THA)前预测髋臼杯假体型号的新方法。方法:选择2021年6月至2022年3月于中国人民解放军总医院第一医学中心行THA的86例股骨头坏死患者进行回顾性分析。测量所有患者术前标准骨盆正位X线片上的骨盆高度。采用简单随机抽样法抽取同期于该院行THA的45例患者,使用Mako机器人计算机操作系统对其术前髋关节三维CT扫描图像进行处理,建立骨盆的三维立体模型,分别测量骨盆标准0°位、向前倾斜(5°、10°、15°)位和向后倾斜(5°、10°、15°)位的骨盆高度。采用简单线性回归模型分析骨盆高度与髋臼杯外径的关系。计算预测的髋臼杯外径与实际使用的髋臼杯外径的组内相关系数(ICC)。结果:所有86例患者骨盆高度与髋臼杯外径之间存在线性关系,简单线性回归方程为:髋臼杯外径=24.82+(骨盆高度×0.13)(P<0.001)。预测的髋臼杯外径和实际使用的髋臼杯外径的ICC=0.757(P<0.001),可重复性较好。骨盆前、后倾15°内的7个位置测量的骨盆高度差值最大为5.8 mm。结论:术前标准骨盆正位X线片的骨盆高度与实际使用的髋臼杯外径之间存在线性关系,使用术前X线片的骨盆高度预测THA术中实际使用的髋臼杯假体型号是可行的;X线片中骨盆前后倾斜15°以内对使用本方法预测髋臼杯假体型号的影响很小。

关键词：全髋关节置换术骨盆高度髋臼杯术前规划

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空穴效应对连杆小头轴承润滑及动力学特性的影响

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内燃机工程 2024年第5期45卷 47-56页

作者：毕玉华段磊磊马雄张国强唐明超昆明理工大学云南省内燃机重点实验室昆明650500 昆明云内动力股份有限公司昆明650217

将热弹流理论与活塞连杆组柔性多体动力学分析结合,利用AVL EXCITE软件建立连杆小头轴承润滑模型,并以油膜压力、轴心轨迹及润滑油填充率确定连杆小头轴承空穴位置,研究空穴效应对连杆小头轴承润滑及动力学特性产生的影响。结果表明,在... 详细信息

将热弹流理论与活塞连杆组柔性多体动力学分析结合,利用AVL EXCITE软件建立连杆小头轴承润滑模型,并以油膜压力、轴心轨迹及润滑油填充率确定连杆小头轴承空穴位置,研究空穴效应对连杆小头轴承润滑及动力学特性产生的影响。结果表明,在发动机整个循环工况中连杆小头轴承一直存在空穴现象。考虑空穴后平均峰值油膜压力降低了6.5 MPa,平均油膜厚度降低了1.35μm,活塞销相对连杆小头轴承的速度及加速度分别增大了1.57μm/s和0.25μm/s^(2),连杆小头轴承润滑性能减弱,所受冲击增大。

关键词：空穴效应连杆小头轴承润滑

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Laboratory Study on CR/SBS Modified Asphalt:Preparation and Performance Characterization

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Journal of Renewable Materials 2022年第6期10卷 1659-1674页

作者： Liang Song guoqiang zhang Hongfei Xie Jie Gao College of Transportation Engineering Tongji UniversityShanghai201804China Xinjiang Transportation Planning Surveying and Design Institute Urumqi830006China Xinjiang NABA Expressway Development Co. Ltd.Urumqi830006China School of Civil Engineering and Architecture East China Jiaotong UniversityNanchang330013China

Crumble rubber(CR)can be used to prepare CR and styrene-butadiene-styrene(SBS)composite modified asphalt with a good high-and low-temperature performance,meanwhile the addition of CR could work as the substitute for SBS and help reduce the content of *** study contains three main parts:effect of preparation and effect of material composition as well as rheological performance *** during the preparation,including shearing temperature,shearing time,mixing time and swelling time,were selected,while base binder,CR content,CR particle size and SBS content in material composition were *** effects of these factors were assessed in terms of the conventional performance(penetration,softening point,ductility and storage stability).After identifying these effects,the sample of CR and SBS modified asphalt at the selected preparing condition and material composition(CR/SBSMA)was made,and the corresponding SBS modified and CR modified asphalt(SBSMA and CRMA)were produced for the comparing ***,temperature sweeps from 0℃ to 80℃ were utilized to depict the viscoelasticity of these modified asphalt binders by complex modulus and phase *** stress creep recovery tests(MSCR)at 64℃ and bending beam rheometer tests(BBR)at various low temperatures were employed to evaluate the high-and low-temperature performance,*** highlight that that CR/SBSMA could exhibit an excellent high-temperature performance(better than SBSMA),and a good low-temperature performance(reaching the level of base binder).

关键词： Crumble rubber styrene-butadiene-styrene preparation material composition high-temperature performance low-temperature performance

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Theoretical Calculation of ITZ Volume Fraction and Morphological Characterization of Crushed Stone in Concrete

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Journal of Wuhan University of Technology(Materials Science) 2022年第4期37卷 656-665页

作者： zhang Jianjian PENG Liang zhang guoqiang SUN Guowen LIU Zhiyong School of Civil Engineering Harbin Institute of TechnologyHarbin 150090China School of Materials Science and Engineering Shijiazhuang TieDao UniversityShijazhuang 050043China Foundational Subjects Department Shijiazhuang TieDao University SiFang CollegeShijiazhuang 051132China School of Materials Science and Engineering Southeast UniversityNanjing 211189China

According to the morphological characteristics of crushed stone,the sphericity was introduced to establish the theoretical calculation model of volume fraction of interfacial transition zone(ITZ)around crushed *** sphericity of crushed stone was obtained by image processing technology and numerical *** experimental results show that when the maximum particle size of coarse aggregate is less than 31.5 mm,the practical sphericity is generally around 0.75,while the sphericity of sand is generally above *** the closer to 1 the practical sphericity is,the smaller the ITZ volume fraction(V_(ITZ))is,that is,the closer to spherical shape the aggregate is,the lower the ITZ content in concrete *** V_(ITZ) and ITZ thickness in concrete and mortar have a linear relationship,and the ITZ content in concrete is lower than that in mortar at the same aggregate volume fraction.

关键词： crushed stone sphericity interfacial transition zone image processing concrete

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风-光-储和需求响应协同的虚拟电厂日前经济调度优化

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广东电力 2024年第2期37卷 18-24页

作者：苟凯杰吕鸣阳高悦陈衡张国强雷兢华北电力大学能源动力与机械工程学院北京102206

目前可再生能源直接并入电网仍然面临稳定性和经济性问题,经过虚拟电厂整合可以缓解对电网的影响。以系统整合后最终运行成本达到最小作为目标,进行新能源出力和负荷在未来24 h的预测,计及电网侧在不同时间内的电价变化情况,采用反向学... 详细信息

目前可再生能源直接并入电网仍然面临稳定性和经济性问题,经过虚拟电厂整合可以缓解对电网的影响。以系统整合后最终运行成本达到最小作为目标,进行新能源出力和负荷在未来24 h的预测,计及电网侧在不同时间内的电价变化情况,采用反向学习的混沌映射自适应粒子群算法对风-光-储能和需求响应不同组合搭配的5种调度方案进行探讨,与原始粒子群算法相比,所提算法可以跳出局部最优解而找到全局最优解。计算结果表明,风-光-储和需求响应都参与供电相比风-光-储供电可以将运行成本降低4.47%,用户舒适度提高3.51%。

关键词：虚拟电厂风-光-储需求响应经济调度反向学习的混沌映射自适应粒子群算法

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直肠瘘或膀胱瘘致盆部顽固疼痛的治疗方法及疗效

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中华肿瘤杂志 2024年第3期46卷 263-268页

作者：张咏梅王刚成刘英俊王有财张国强张燕高重庆王聪张志杨珺晋莉王燕萍牛竹林银川市第一人民医院妇科、宁夏医科大学第二临床医学院银川750001 郑州大学第一附属医院腹盆部肿瘤外科郑州450052 河南省肿瘤医院、郑州大学附属肿瘤医院普外科郑州450008

目的探讨宫颈癌、直肠癌综合治疗(放疗、手术、化疗及其他治疗)后出现直肠瘘、膀胱瘘导致盆部顽固疼痛的治疗方法及疗效。方法回顾性分析2016年6月至2022年6月银川市第一人民医院和郑州大学附属肿瘤医院收治盆腔疼痛患者的临床病理资料... 详细信息

目的探讨宫颈癌、直肠癌综合治疗(放疗、手术、化疗及其他治疗)后出现直肠瘘、膀胱瘘导致盆部顽固疼痛的治疗方法及疗效。方法回顾性分析2016年6月至2022年6月银川市第一人民医院和郑州大学附属肿瘤医院收治盆腔疼痛患者的临床病理资料,探讨患者综合治疗后出现盆部顽固疼痛的原因,观察临床治疗后相应的疗效。结果32例肿瘤患者综合治疗后出现盆部顽固性疼痛,其中宫颈癌22例,直肠癌10例。全组患者术前疼痛评分为(7.88±1.31)分。32例患者中,直肠阴道瘘或回肠阴道瘘16例,膀胱阴道瘘9例,直肠会阴瘘5例,膀胱阴道直肠瘘2例。32例患者初期给予药物止痛治疗,并根据溃破脏器行相应的近端肠管及肾盂造瘘,截留肠内容物及尿液,疼痛未明显缓解,以上方式治疗1周疼痛评分为(8.13±1.13)分,与术前相比,差异无统计学意义(P=0.417)。后期根据肿瘤是否复发、脏器是否有保留价值、手术是否受益、生存时间与提高生活质量权衡等综合评判,行病变脏器切除或修补,手术方式包括瘘口的修补、局部清创+近端肠液截留冲洗、乙状结肠远端闭合+近端造瘘术、后盆腔脏器切除、前盆腔脏器切除和全盆腔脏器切除术,术后1周患者疼痛完全缓解或消失,疼痛评分为(1.72±1.37)分,与术前、初期手术之治疗前比较差异均有统计学意义(均P<0.001)。结论姑息性肾盂造瘘及近端肠管造瘘不能有效缓解盆底顽固性疼痛,缓解疼痛的根本方法为彻底阻断肠液、尿液的感染。

关键词：宫颈肿瘤直肠肿瘤直肠阴道瘘膀胱阴道瘘疼痛手术治疗放疗损伤

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Experimental Study on Insulation Properties of Epoxy Casting Resins Using High-frequency Square Waveforms

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CSEE Journal of Power and Energy Systems 2021年第6期7卷 1227-1237页

作者： Yikun Zhao guoqiang zhang Dong Han Kang Li Zongjia Qiu Fuyao Yang the Institute of Electrical Engineering Chinese Academy of Sciencesand University of Chinese Academy of SciencesBeijing 100190China the Institute of Electrical Engineering Chinese Academy of SciencesBeijing 100190China the Global Energy Interconnection Research Institute Beijing 102209China

Although the transmission efficiency of high-voltage high-frequency transformers improve as the rated frequency increases,their insulation performance is severely *** a high-frequency experimental platform,insulation tests on epoxy casting resins are carried out using high-frequency square wave ***,the variations of discharge inception and flashover voltages with frequency were analyzed based on the Secondary Electron Emission Avalanche(SEEA)*** breakdown characteristics of epoxy casting resins are studied based on the Weibull distribution analysis and inverse power function ***,an insulation test standard is proposed based on the breakdown characteristics of epoxy casting resins for dry-type HV-HF *** results show that,the flashover voltages are noticeably reduced with the increase of frequency while the discharge inception is hardly affected by ***,the drop in breakdown voltages and insulation lifetime shortening are caused by high-frequency thermal ***,the applied voltages of epoxy resin cast dry-type HV-HF transformers are recommended to be 3.27 to 3.49 times their maximum operating voltages in 1min applied withstand *** applied voltages of the induced withstand tests should be 2.20 to 2.52 times their maximum operating voltages.

关键词： Breakdown characteristics HV-HF transformer insulation test standard surface discharge

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THE DYNAMIC BUCKLING OF ELASTIC-PLASTIC COLUMN SUBJECTED TO AXIAL IMPACT BY A RIGID BODY

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Acta Mechanica Solida Sinica 2005年第3期18卷 256-264页

作者： Han Zhijun Wang Jingchao Cheng guoqiang Ma Hongwei zhang Shanyuan Institute of Applied Mechanics Taiyuan University of Technology Taiyuan 030024 China

The dynamic buckling of an elastic-plastic column subjected to axial impact by a rigid body has been discussed in this paper. The whole traveling process of elastic-plastic waves under impact action is analyzed with the characteristics method. The regularity of stress changes in both column ends and the first separating time of a rigid body and column are obtained. By using the energy principle and taking into account the propagation and reflection of stress waves the lateral disturbance equation is derived and the power series solution is given. In addition, the critical buckling condition can be obtained from the stability analysis of the solution. By numerical computation and analysis, the relationship among critical velocity and impact mass, hardening modulus, and buckling time is given.

关键词： dynamic buckling stress wave critical criteria power series solution

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