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Three-dimensional numerical simulation of flow around a circular cylinder under combined steady and oscillatory flow

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Three-dimensional numerical simulation of flow around a circ...

Numerical Simulations of the Performance of Steel guardrails Under Vehicle Impact

第九届国际水动力学会议

作者： Ming Zhao Liang Cheng hong-wei An School of Civil and Resource Engineering The University of Western Australia 35 Stirling Highway Crawley wa 6009 Australia

Combined steady and oscillatory flow past a circular cylinder is investigated numerically by three-dimensional Direct Numerical Simulation（DNS）.The incompressible Navier-Stokes equations are solved by finite element method（FEM）.The aim of this study is to investigate influence of the existence of steady current on the flow regime and hydrodynamics *** computational results of pure oscillatory flow past a circular cylinder agree well with the experimental *** flow ratios（ratio of current velocity to oscillatory velocity amplitude） are 0.0,0.2 0.5 and 1.0 in the *** influence of the flow ratio on the vortex shedding regime and hydrodynamic forces on the cylinder are investigated numerically.

关键词： Circular cylinder steady flow oscillatory flow hydrodynamic forces vortex shedding

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Transactions of Tianjin University 2008年第5期14卷 318-323页

作者： HAO hong DEEKS J Andrew WU Chengqing School of Civil and Resource Engineering the University of Western Australia 35 Stirling Highway Crawley WA 6009 Australia School of Civil Environmental and Mining Engineering the University of Adelaide North Terrace SA5005 Australia

Road side barriers are constructed to protect passengers and contain vehicles when a vehicle crashes into a barrier. In general, full-scale crash testing needs to be carried out if a geometrically and structurally equivalent barrier has not previously been proven to meet the requirements of containing the vehicle and dissipating sufficient impact energy for passenger protection. As full-scale crash testing is very expensive, the number of data that can be measured in a test is usually limited, and it may not always be possible to obtain good quality measurements in such a test, a reliable and efficient numerical simulation of crash testing is therefore very useful. This paper presents finite element simulations of a 3-rail steel road traffic barrier under vehicle impact. The performance levels defined in Australian Standards AS5100 Clause 10.5 for these barriers are checked. The numerical simulations show that the barrier is able to meet low performance levels. However, the maximum deceleration is higher than the acceptable limit for passenger protection. If present, a kerb launches the vehicles into the barrier, allowing for the possibility of overriding the barrier under certain circumstances, but it redirects the vehicle and reduces the incident angle, which reduces impact force on the barrier. Further investigation into all common kerb profiles on roads should be carried out, as only one kerb profile is investigated in this study.

关键词： vehicle impact steel barrier kerb performance level vehicle containment passenger protection

Field Evaluation of Alternative Testing Strategies for the Detection of HIV Infection in Beijing

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Biomedical and Environmental Sciences 2007年第4期20卷 265-268页

作者： FA-XIN HEI YAN JIANg wei-DONg SUN QI-YUN ZHANg QIN ZHANg JINg-RONg YE HAI-LIN LIU hong-YAN LU AND XIONg HE Division of STD/AIDS Prevention Beijing Centers for Disease Control and Prevention Beijing 100013 China National Center for AIDS/STD Control and Prevention Chinese Center for Disease Control and Prevention Beijing 100050 China

To identify a cost-efficient altemative antibody testing strategy for screening and confirmation of HIV infection by rapid simple tests （RSTs） and enzyme-linked immunosorbent assays （ELISAs）. Methods Four RSTs （RST1, RST2, RST3, and RST4 ） and five ELISAs （ELISA1, ELISA2, ELISA3, ELISA4, and ELISA5） were evaluated in two phases by using banked and serum specimens prospectively collected at regional hospitals and voluntary counseling and testing （VCT） centers in Beijing. A total of 200 banked serum specimens were included in the first phase, including 62 HIV-positive, 127 HIV-negative and 11 indeterminate specimens. All specimens were tested by four RSTs and five ELISAs respectively. The second phase involved prospective testing of 389 routine specimens, including 92 HIV-positive, 287 HIV-negative, and 10 indeterminate specimens. All the specimens were tested by two RSTs （RST2 and RST4） and three ELISAs （ELISA1, ELISA3, and ELISA4）, which were selected for their respective excellent sensitivity and/or specificity. Westem blot （WB） was used as a gold standard for confirming the reactivity of all the specimens. Results Sensitivity, specificity, and efficacy were calculated for each assay in two phases. In the first phase, four assays （ELISA4, RST2, RST3, and RST4） had a specificity of 100%. For the determination of efficacy, ELISA4, RST2, and RST4 were selected in the second phase. ELISA1 and ELISA3 which have a sensitivity of 95.9% and 93.2% respectively also entered this phase. In the second phase, all the five assays （ELISA1, ELISA3, ELISA4, RST2, and RST4） had a sensitivity and specifity of over 90%. ELISA1 had a sensitivity of 99% and ELISA4 a specificity of 99%. Conclusion The sensitivity ELISA1 and the specificit of ELISA4 are comparable to ELISA/WB standard strategy. Application of this alternative testing strategy provides a cost-effective method for determining HIV prevalence in Beijing.

关键词： Human immunodeficiency virus type-l Altemative testing strategy Rapid simple test Enzyme-linkedimmunosorbent assay

基于联系数贴近度的区间型组合预测模型及其有效性

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统计与信息论坛 2017年第6期32卷 31-37页

作者：袁宏俊韦晨珺娃钟梅安徽财经大学统计与应用数学学院安徽蚌埠233030

利用区间数和二元联系数的相互转化关系,把区间数组合预测问题转换成二元联系数组合预测问题。在联系数贴近度的最优准则下,建立基于联系数贴近度的区间型组合预测模型,分析了该模型的有效性理论,包括:基于联系数贴近度的区间型组合预... 详细信息

利用区间数和二元联系数的相互转化关系,把区间数组合预测问题转换成二元联系数组合预测问题。在联系数贴近度的最优准则下,建立基于联系数贴近度的区间型组合预测模型,分析了该模型的有效性理论,包括:基于联系数贴近度的区间型组合预测模型是非劣性组合预测、优性组合预测的充分条件定理,基于联系数贴近度的区间型组合预测模型的冗余预测方法的存在性和冗余方法的判定定理。对某省社会保障水平适度区间值进行组合预测的实证分析,结果显示所建立的模型能有效提高预测的精度。

关键词：组合预测区间数联系数贴近度有效性

Virus-Host Interactions Drive Contrasting Bacterial Diel Dynamics in the Ocean

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Research 2024年第2期6卷 389-399页

作者： Xiaowei Chen Chen Hu wei wei Yunlan Yang Markus g.weinbauer hongbo Li Shiying Ren Ruije Ma YVibin Huang Tingwei Luo Nianzhi Jiao Rui Zhang State Key Laboratory of Marine Environmental Science College of Ocean and Earth SciencesFujian Key Laboratory of Marine Carbon SequestrationXiamen UniversityXiamen 361102PR China College of the Environment and Ecology Xiamen UniversityXiamen 361102PR China Research Center for Environmental Ecology and Engineering School of Environmental Ecology and Biological EngineeringWuhan Institute of TechnologyWuhan 430205PR China Sorbonne Universités UPMCUniversitéParis 06CNRSLaboratoire d'Oceanographie de Villefranche(LOV)Villefranche-sur-Mer 06230France National Marine Environmental Monitoring Center Ministry of Ecological EnvironmentDalian 116023PR China Department of Ocean Sciences University of CaliforniaSanta CruzCAUSA NOAA/OAR Pacific Marine Environmental Laboratory SeattleWAUSA Institute for Advanced Study Shenzhen UniversityShenzhen 518055PR China

Marine organisms perform a sea of diel *** diel dynamics have been shown to be driven by light,energy resources,circadian rhythms,and the coordinated coupling of photoautotrophs and heterotrophic ***,we explore the diel fluctuation of viral production and decay and their impact on the total and active bacterial community in the coastal and open seawaters of the South China *** results showed that the night-production diel pattern of lytic viral production was concurrent with the lower viral decay at night,contributing to the accumulation of the viral population size during the night for surface *** diel variations in bacterial activity,community composition,and diversity were found highly affected by viral *** was revealed by the finding that bacterial community diversity was positively correlated to lytic viral production in the euphotic zone of the open ocean but was negatively related to lysogenic viral production in the coastal *** distinct but contrasting correlations suggest that viral life strategies can not only contribute to diversifying bacterial community but also potentially piggyback their host to dominate bacterial community,suggesting the tightly synchronized depth-dependent and habitat-specific diel patterns of virus-host *** further implies that viruses serve as an ecologically important driver of bacterial diel dynamics across the ocean,highlighting the viral roles in bacterial ecological and biogeochemical processes in the ocean.

关键词： coastal ocean Marine

Study on polarization properties of graphene coated D-shaped fiber

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Chinese Physics B 2018年第10期27卷 346-351页

作者： Xuejing Liu Luwen Yang Jingyun Ma Caili Li wa Jin weihong Bi School of Instrumentation Science and Opto-electronics Engineering Beihang UniversityBeijing 100191China School of Information Science and Engineering Key Laboratory for Special Fiber and Fiber Sensor of Hebei ProvinceYanshan UniversityQinhuangdao 066004China Key Laboratory for Special Fiber and Fiber Sensor of Hebei Province School of Information Science and EngineeringQinhuangdao 066004China

The optical properties of graphene coated D-shaped single mode fiber and photonic crystal fiber are numerically analyzed. Enhancement of the graphene-light interaction is found in graphene coated D-shaped photonic crystal fiber,which introduces a tunable polarization of the D-shaped fiber by changing the chemical potential of the coated *** optimal polarizer model is demonstrated with the extinction ratio of 66.26 dB/mm and the insertion loss of 9.4 dB/*** modulator extinction ratios of the TE mode and TM mode are 11.5 dB and 5 dB, respectively, with a device length of100 μm. This paper provides a theoretical reference for the optical property research of the graphene fiber.

关键词： photonic crystal fiber graphene polarization chemical potential

Endoscopic surgery for intraventricular hemorrhage:A comparative study and single center surgical experience

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World Journal of Clinical Cases 2022年第16期10卷 5208-5216页

作者： Feng-Bo wa.g Xiao-wa Yuan Jin-Xiao Li Ming Zhang Zhao-Hui Xiang Department of Neurosurgery Xinyi People's HospitalXinyi 221400Jiangsu ProvinceChina

BACKgROUND Intraventricular hemorrhage is a neurosurgical emergency,and a dangerous condition associated with high morbidity and ***,hematoma evacuation is generally executed by external intracranial drainage(EVD)or surgical ***,endoscopic evacuation is emerging as a good alternative because it brings relatively less invasion and ***,successful endoscopic evacuation requires skilled manipulation of endoscopic devices and the evidence supporting its efficacy differs in different *** To improve the technique usage and provide more evidence of endoscopic evacuation efficacy,we summarize our surgical experience and compared the outcomes of the endoscopic evacuation with EVD using real-world *** We retrospectively studied 96 consecutive patients with intraventricular hemorrhage who underwent either endoscopic surgery(n=43)or non-endoscopic surgery(n=53)for hemorrhage evacuation between November 2013 and September 2019 in our ***’conditions prior to and after the operation were evaluated and analyzed to assess the efficacy of the *** consciousness status improvement and perioperative in-hospital parameters in the two types of operation groups were assessed and *** Patients in the endoscopic and non-endoscopic groups presented with a similar state of consciousness,with a comparable glasgow Coma Scale(gCS)*** average operation time of the endoscopic group was longer than that of the nonendoscopic group(median 2.42 h vs 1.08 h,Pgh the endoscopic group was older and had a baseline graeb score that indicated more severe hemorrhage than the non-endoscopic group(graeb median:Endoscopic group=9 vs non-endoscopic group=8,P=0.023),the clearance rate of hematoma was as high as 60.5%.Both the endoscopic and non-endoscopic groups showed an improved gCS index after ***,this improvement was more marked in patients in the endoscopic group(median improvement of g

关键词： Ventriculoscope Intraventricular hemorrhage Minimal invasion Ventricular irrigation fluid Endoscopic evacuation Efficacy

Holocene activities of the Taigu fault zone,Shanxi Province, and their relations with the 1303 hongdong M=8 earthquake

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Acta Seismologica Sinica(English Edition) 2004年第3期17卷 308-321页

作者： XIE Xin-sheng(谢新生) JIANg wa-li(江娃利) wa.g Huan-zhen(王焕贞) FENg Xi-ying(冯西英) Institue of Crust Dynamics China Earthquake AdministrationBeijing100085China Institue of Crust DynamicsChina Earthquake AdministrationBeijing100085China Institue of Crust DynamicsChina Earthquake AdministrationBeijing100085China Institue of Crust DynamicsChina Earthquake AdministrationBeijing100085China

No abstract available

关键词： Taigu fault Holocene activities 1303 hongdong earthquake surface rupture zone

全膝关节置换过程中股骨假体旋转对髌股关节接触压影响的有限元分析

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中国组织工程研究 2022年第6期26卷 848-852页

作者：黄浩洪嵩瓦庆德遵义医科大学附属医院贵州省遵义市563000

背景:髌股关节并发症是全膝关节置换后的常见并发症,置换中股骨假体旋转不良会影响髌股关节的一致性,引起髌股关节接触力及运动学的改变。目的:通过有限元分析方法,研究全膝关节置换中当股骨假体在不同旋转角度放置时屈膝过程中的髌股... 详细信息

背景:髌股关节并发症是全膝关节置换后的常见并发症,置换中股骨假体旋转不良会影响髌股关节的一致性,引起髌股关节接触力及运动学的改变。目的:通过有限元分析方法,研究全膝关节置换中当股骨假体在不同旋转角度放置时屈膝过程中的髌股关节接触压变化。方法:根据志愿者右膝关节的CT、MRI数据,建立自然膝关节的三维模型。模拟全膝关节置换过程,股骨假体参照股骨外科上髁轴线(股骨内侧髁沟与股骨外侧髁最凸起点之间的连线)以3°为增量,从内旋6°至外旋9°安装(外旋3°、6°、9°,旋转0°,内旋3°、6°),而胫骨假体参考Akagi线(髌腱内侧缘与后交叉韧带止点中央的连线)旋转0°固定放置,建立全膝关节置换膝关节三维模型。将膝关节的三维模型进行网格划分,得到膝关节的有限元模型,并通过计算提取,获得各膝关节模型在屈膝过程中的髌股关节接触压。结果与结论:(1)所有模型的髌股关节接触压均随着膝关节屈曲加深而增高。股骨假体外旋3°组的髌股关节接触压均低于旋转0°组,当外旋大于3°时,随着假体外旋度数增加,髌股关节接触压增大。股骨假体内旋3°组和内旋6°组在屈膝过程中的髌股关节接触压明显高于其他组,且内旋6°组的接触压最高。(2)结果表明在全膝关节置换术中,当以上髁轴为股骨假体旋转的参考轴线时,外旋3°有可能减少髌股关节接触压,而过度的外旋股骨假体则可能导致髌股关节接触压的增大;置换中应避免股骨假体内旋,大于3°的内旋不良可能会导致髌股关节接触压明显增大,增加置换后膝前疼痛以及假体磨损的风险。

关键词：膝关节髌股关节全膝关节置换有限元股骨假体旋转对线接触压生物力学