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基于摇摆与剪切协同的柱脚叉接木框架抗侧荷载-位移曲线模型 被引量:2
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作者 吴亚杰 宋晓滨 顾祥林 《土木工程学报》 EI CSCD 北大核心 2021年第12期32-40,共9页
榫卯连接木框架是传统木结构中的基本承力构件,研究表明其在竖向和水平荷载共同作用下具有摇摆和剪切两种抗侧机制。文章综合考虑木框架摇摆与剪切变形,根据变形协调和弯矩平衡条件,推导竖向荷载和水平荷载共同作用下,柱脚叉接榫卯连接... 榫卯连接木框架是传统木结构中的基本承力构件,研究表明其在竖向和水平荷载共同作用下具有摇摆和剪切两种抗侧机制。文章综合考虑木框架摇摆与剪切变形,根据变形协调和弯矩平衡条件,推导竖向荷载和水平荷载共同作用下,柱脚叉接榫卯连接木框架抗侧荷载-位移关系的曲线模型,提出木框架抗侧弹性极限荷载点、峰值荷载点及其切线刚度和下降段刚度的计算方法。基于叉接柱脚木框架抗侧试验对模型进行验证,结果表明:理论模型与试验结果吻合较好,模型计算结果误差小于15.5%。理论研究成果对于传统木结构抗震性能分析和设计具有参考价值。 展开更多
关键词 榫卯连木框架 柱脚叉接 摇摆和剪切抗侧机制 抗侧荷载-位移关系 理论模型
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PCCP开叉接驳过程接头橡胶圈结构数值模拟
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作者 林禄杰 徐国元 +1 位作者 肖金军 关炜宸 《水电能源科学》 北大核心 2022年第5期113-117,共5页
鉴于分析研究预应力钢筒混凝土管拉拨及安装过程橡胶受力情况较少的问题,结合西江引水占压段管线迁改工程,利用有限元软件ABAQUS建立预应力钢筒混凝土管承插口精细化模型,分析管道开叉接驳过程中,接头橡胶圈的应力、接触压力、拉拔力与... 鉴于分析研究预应力钢筒混凝土管拉拨及安装过程橡胶受力情况较少的问题,结合西江引水占压段管线迁改工程,利用有限元软件ABAQUS建立预应力钢筒混凝土管承插口精细化模型,分析管道开叉接驳过程中,接头橡胶圈的应力、接触压力、拉拔力与安装力的变化规律及安装力与摩擦系数的关系。结果表明,橡胶圈与承口钢环外倒角接触位置存在应力集中;旧管头拔出及新钢管安装过程,拉拔力与安装力均出现两个峰值,且拉拔力峰值大于安装力峰值;安装力与摩擦系数近乎呈线性关系;安装完成时的接触压力大于现场管道的设计工作压力及试验压力,证明接头橡胶圈的密封性可以满足现场施工需要。研究结果可为类似管道开叉接驳施工提供工程指导。 展开更多
关键词 预应力钢筒混凝土管 叉接 拉拔力 安装力 有限元分析
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有限元分析在给水管不停水开叉接驳中的应用
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作者 许可铭 《工程技术研究》 2023年第17期35-37,共3页
给水管不停水开叉接驳过程中,若三通管应力分布不均,可能发生破坏。文章利用有限元分析模型,对三通及其配件进行了应变和Mises应力等分析,得出三通及其配件不同状态时的最大Mises应力和应变位置,并将结果应用到城中村管道不停水开叉接... 给水管不停水开叉接驳过程中,若三通管应力分布不均,可能发生破坏。文章利用有限元分析模型,对三通及其配件进行了应变和Mises应力等分析,得出三通及其配件不同状态时的最大Mises应力和应变位置,并将结果应用到城中村管道不停水开叉接驳改造工程实例中,为三通设计提供技术指导与参考价值。 展开更多
关键词 不停水开叉接 三通管 有限元分析 ABAQUS
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武术旋风脚720°接跌叉稳定性的研究 被引量:21
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作者 陈建民 《体育科学研究》 1999年第3期29-32,共4页
武术旋风脚 72 0°接跌叉是九运会武术指定动作之一。通过对该组动作落地技术的动力学以及构成稳定性条件的分析 ,提出合理的落地技术和训练中需解决的问题。
关键词 武术 旋风脚720° 稳定性 落地技术 下肢动作技术 头部动作技术 躯干前倾角度
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梅寒旋子转体720°接竖叉落地技术的运动学分析 被引量:2
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作者 郭明明 《沈阳体育学院学报》 2006年第5期120-122,共3页
难度动作是武术运动员比赛成绩的决定因素。成功完成旋子转体720°接竖叉可获得0.6分的难度得分,而目前该动作的完成情况并不理想,尤其是在落地接竖叉过程中经常出现失误。应用DLT法,对第十届全国运动会女子长拳冠军梅寒完成的旋... 难度动作是武术运动员比赛成绩的决定因素。成功完成旋子转体720°接竖叉可获得0.6分的难度得分,而目前该动作的完成情况并不理想,尤其是在落地接竖叉过程中经常出现失误。应用DLT法,对第十届全国运动会女子长拳冠军梅寒完成的旋子转体720°接竖又的落地技术进行分析,旨在揭示动作的运动规律,为教练员以后的训练工作提供科学参考。结论:在整个落地过程中,梅寒始终保持梗头,有利于提高落地的稳定性;梅寒的两臂总是在左脚落地后快速向两侧伸展,两臂的位置,有利于及时调整重心;梅寒的上体从右脚落地瞬间便开始积极地前倾,既提高了落地的稳定性,又加强了对落地的缓冲作用。 展开更多
关键词 梅寒 旋子转体720° 落地技术 运动学分析 武术运动员 难度动作 第十届 全国运动会 女子长拳 冠军
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2300三辊劳特轧机万向接轴叉头磨损分析
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作者 陶魄 《南钢科技与管理》 1997年第1期43-46,共4页
2300三辊劳特式轧机是我中板厂主要开坯初轧机。该轧机的轧制力是15000kN,最大开口度可达400mm,正常生产一般在260mm以下。最大力矩是1500kN—m。传递扭矩的万向接轴最大摆角为2.86°,同时该轴还承受着轧机往复轧制的冲击负荷,由于... 2300三辊劳特式轧机是我中板厂主要开坯初轧机。该轧机的轧制力是15000kN,最大开口度可达400mm,正常生产一般在260mm以下。最大力矩是1500kN—m。传递扭矩的万向接轴最大摆角为2.86°,同时该轴还承受着轧机往复轧制的冲击负荷,由于联接轴在设计时安全系数考虑较小,往往在A、B面磨损到一定程度后(见图1)。 展开更多
关键词 万向 允许磨损 初轧机 劳特式轧机 磨损寿命 工作时间 预防性维修 安全系数 轧制力
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三相四线有功电能表接线中不可忽视的问题 被引量:1
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作者 杨淑兰 曹生彪 王晓丽 《包钢科技》 2009年第1期45-46,63,共3页
文章指出了三相四线有功电能表零线采用T接或叉接的必要性,分析了三相四线有功电能表经电流互感器接入时三相二次回路共用并一点接地的弊端,提出了三相四线有功电能表经电流互感器接入时的正确接线方式。
关键词 三线四线有功电能表 电流互感器 零线 T 叉接
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多端元件的端口组态分析的一种系统化分析方法——叉阻抗变换法
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作者 奚寿根 《苏州丝绸工学院学报》 1992年第4期59-64,共6页
本文从多端元件的基本叉接和叉接变换出发,分析任意叉接方式下的叉阻抗矩阵,并运用这种变换计算任意端口组态下的开路阻抗参数矩阵.
关键词 多端元件 叉接 端口组态 系统化
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钢丝绳挡矸网在倾斜综采工作面中的应用 被引量:1
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作者 金海城 《江西煤炭科技》 2012年第4期119-120,共2页
采用综采工艺开采倾斜煤层时,由于工作面倾角大,易产生飞块,传统方法是在工作面软帮侧人行道内设置皮带。该方法不仅影响通风,也对作业人员视线造成遮挡,并且挡矸效果非常差,综采工作面飞块伤人事故时有发生。采取何种措施才能有效预防... 采用综采工艺开采倾斜煤层时,由于工作面倾角大,易产生飞块,传统方法是在工作面软帮侧人行道内设置皮带。该方法不仅影响通风,也对作业人员视线造成遮挡,并且挡矸效果非常差,综采工作面飞块伤人事故时有发生。采取何种措施才能有效预防工作面飞块伤人事故,是煤矿安全技术管理人员迫切需要解决的问题。 展开更多
关键词 飞块 挡矸帘 挡矸网 叉接
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川中蛟龙腾飞时
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《广东社会科学》 CSSCI 1992年第4期129-2,共2页
龙川县总面积3089平方公里、人口76.1万、海外华侨和港澳台同胞32.7万人,随着正在动工兴建的广梅汕铁路与规划兴建的全国南北第2条大动脉京九铁路在该县交叉接轨,该县不久将成为福建漳厦地区,江西赣南地区,广东潮汕、梅州、惠州、广州... 龙川县总面积3089平方公里、人口76.1万、海外华侨和港澳台同胞32.7万人,随着正在动工兴建的广梅汕铁路与规划兴建的全国南北第2条大动脉京九铁路在该县交叉接轨,该县不久将成为福建漳厦地区,江西赣南地区,广东潮汕、梅州、惠州、广州、深圳、珠海,直至香港九龙的结合部,成为重要交通枢纽和广东独有的中转站. 展开更多
关键词 蛟龙 川中 叉接 工农业总产值 京九铁路 龙川县 赣南地区 广梅汕铁路 广东潮汕 固定资产投入
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The Mechanism of Eliminating Harmonic Resonance with Controllers and Application to the Power Systems
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作者 吴琼 计国君 +1 位作者 宋文忠 戴先中 《Journal of Southeast University(English Edition)》 EI CAS 2002年第2期164-172,共9页
The phenomenon of anti-symmetrical bifurcation of periodic solutionsoccurring near an integral manifold is the intrinsic cause resulting in harmonic resonanceover-voltage in power systems. Due to this discovery, the p... The phenomenon of anti-symmetrical bifurcation of periodic solutionsoccurring near an integral manifold is the intrinsic cause resulting in harmonic resonanceover-voltage in power systems. Due to this discovery, the principle of eliminating resonance byusing anti-bifurcation technique is presented, which makes that the theoretical bases of verymeasure to eliminate resonance are unified firstly from a point of view of basic theory. Ourdiscussion models depend on a class of nonlinear control model. Using the direct Lyapunov method, acomplete theoretical proof is given in accordance with the measure of eliminating resonance byconnecting nonlinear resistor in series to the neutral point of P. T., and the feedback control lawbeing applied. It comprises the action of parameters of resistor to eliminate resonance and theactual process of eliminating resonance, i.e., to go against bifurcation process which forces thebig harmonic solutions to retreat to the integral manifold gradually and disappear eventually, whichby using the nonlinear controllers. This makes it sure that the intrinsic cause of resonance iseliminated thoroughly. The obtained theory results and computing results are better than thepresented results. 展开更多
关键词 eliminate resonance feedback control law OVER-VOLTAGE BIFURCATION MANIFOLD
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振动沉模混凝土超薄防渗板墙的工程实践
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作者 林志潘 《水利建设与管理》 2012年第5期44-47,共4页
福建闽南地区土坝坝体的防渗处理采用振动沉模混凝土超薄防渗板墙技术,避免了一般混凝土防渗墙的某些缺陷,圆满地完成了防渗加固任务,为类似工程的施工积累了丰富的经验。
关键词 振动沉模混凝土超薄防渗墙 槽孔间的开叉接 施工工艺
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Fork-Join program response time on multiprocessors with exchangeable join 被引量:1
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作者 WANG Yong-cai ZHAO Qian-chuan ZHENG Da-zhong 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2006年第6期927-936,共10页
The Fork-Join program consisting of K parallel tasks is a useful model for a large number of computing applications. When the parallel processor has multi-channels, later tasks may finish execution earlier than their ... The Fork-Join program consisting of K parallel tasks is a useful model for a large number of computing applications. When the parallel processor has multi-channels, later tasks may finish execution earlier than their earlier tasks and may join with tasks from other programs. This phenomenon is called exchangeable join (EJ), which introduces correlation to the task’s service time. In this work, we investigate the response time of multiprocessor systems with EJ with a new approach. We analyze two aspects of this kind of systems: exchangeable join (EJ) and the capacity constraint (CC). We prove that the system response time can be effectively reduced by EJ, while the reduced amount is constrained by the capacity of the multiprocessor. An upper bound model is constructed based on this analysis and a quick estimation algorithm is proposed. The approximation formula is verified by extensive simulation results, which show that the relative error of approximation is less than 5%. 展开更多
关键词 Exchangeable join First come first served (FCFS) Fork-Join MULTIPROCESSOR Response time
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Research on meshing theory of noninvolute beveloid gears 被引量:2
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作者 李瑰贤 温建民 +2 位作者 李笑 刘福利 刘宇 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2003年第2期154-156,共3页
A mathematical model has been developed using the space engagement theory and the differential geometry for the line contact of noninvolute beveloid gears with intersecting axes with their tooth profile equations and ... A mathematical model has been developed using the space engagement theory and the differential geometry for the line contact of noninvolute beveloid gears with intersecting axes with their tooth profile equations and engagement equations established for the first time and their meshing theory analysed. It can be seen from the fact that the tooth profile equation finally derived is no longer a standard involute helicoid and standard involute beveloid gears with intersecting axes have no way to satisfy the line contact requirement. However, the noninvdute beveloid gears derived in this paper satisfy the line contact requirement very well. All these work will inevitably facilitate further investigations into gear tooth generation, stiffness, backlash and efficiency of transmission. 展开更多
关键词 noninvolute beveloid gears intersecting axes line contact
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Numerical Simulations of Intraband Crosstalk in Optical Cross Connect
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作者 WUJian-hua TANXu-dong 《Semiconductor Photonics and Technology》 CAS 2003年第1期18-22,25,共6页
All optical network based on wavelength division multiplexing transmission system with optical cross connect (OXC) is an essential approach for optical commumications.Crosstalk introduced by OXC (specially large scale... All optical network based on wavelength division multiplexing transmission system with optical cross connect (OXC) is an essential approach for optical commumications.Crosstalk introduced by OXC (specially large scale one) is a key limiting factor for its capacity. Optical signal passing through a typical OXC is analyzed in this paper, followed by description of the generation and effect of intraband crosstalk.The power penalties induced by intraband crosstalk versus the number of multiplexed wavelengths M and the number of input fibers N have been given by numerical simulations. The results show that the coherent crosstalk is the most critical limitation on OXC and depends more closely on the number of multiplexed wavelengths M than the number of input fibers N . Crosstalk is suppressed by doubly filtering, fixing optimum decision-threshold and appropriately choosing the number of multiplexed wavelengths M . 展开更多
关键词 Wavelength division multiplexing Optical cross connect Intraband crosstalk Optical power penalty CLC number:TN929.11 Document code:
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Influence of EDFA's Characteristics on Performance of All Optical Network
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作者 WANGTian-zhu YUCong-xiu 《Semiconductor Photonics and Technology》 CAS 2002年第2期70-74,79,共6页
The characteristic of EDFA in WDM system is analyzed. The simulation system based on the architecture of the China Information Network (CAINONET) is introduced, and the influence of noise figure, gain unflatness and o... The characteristic of EDFA in WDM system is analyzed. The simulation system based on the architecture of the China Information Network (CAINONET) is introduced, and the influence of noise figure, gain unflatness and output power of EDFA on the BER performance and scale of network is investigated. Moreover, the influence of noise figure is studied with different crosstalk . Meanwhile, it is indicated that it is important to apply the "node isolation principle" in the optical network. The research results can provide the valuable reference for the practical construction of all optical network . 展开更多
关键词 EDFA WDM Optical add/drop multiplexer Optical cross-connection China information network
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Microscopic dynamic simulation model for pedestrian at signalized intersection 被引量:2
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作者 李珊珊 钱大琳 罗艺 《Journal of Central South University》 SCIE EI CAS 2012年第11期3351-3362,共12页
Pedestrian's road-crossing model is the key part of micro-simulation for mixed traffic at signalized intersection.To reproduce the crossing behavior of pedestrians,the microscopic behaviors of the pedestrians pass... Pedestrian's road-crossing model is the key part of micro-simulation for mixed traffic at signalized intersection.To reproduce the crossing behavior of pedestrians,the microscopic behaviors of the pedestrians passing through the crosswalk at signalized intersection were analyzed.A pedestrian's decision making model based on gap acceptance theory was proposed.Based on the field data at three typical intersections in Beijing,China,the critical gaps and lags of pedestrians were calibrated.In addition,considering pedestrian's required space,a modification of the social force model that consists of a self-deceleration mechanism prevents a simulated pedestrian from continuously pushing over other pedestrians,making the simulation more realistic.After the simple change,the modified social force model is able to reproduce the fundamental diagram of pedestrian flows for densities less than 3.5 m-2 as reported in the literature. 展开更多
关键词 communication and transportation system pedestrian simulation social force model decision making model fimdamental diagram mixed traffic
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Changes of macromolecular organizations in nonjunctional sarcolemmas after cross-innervation──a study offast-and slow-twitch muscle fibres in rats
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作者 LU JIANLI TIEFENG ZHANG +2 位作者 FUJIN QU BEIHUA QIAN SHIKAI HUANG(Shanghai Institute of Physiology, Chinesc Academy of Scicnces, 320 Yue-Yang Road, Shanghai 200031, China) 《Cell Research》 SCIE CAS CSCD 1995年第2期143-154,共12页
The purpose of the present study was to analyse the changes of macromolecular organizations in nonjunctional sarcolemmas of different types of skeletal muscle fibres after cross-innervation. In normal rats the mean de... The purpose of the present study was to analyse the changes of macromolecular organizations in nonjunctional sarcolemmas of different types of skeletal muscle fibres after cross-innervation. In normal rats the mean density of square arrays (6 nm particles organized in orthogonal arrays) was 9.02/μm2 for the nonjunctional sarcolemmas of fast-twitch extensor digitorum longus (control EDL,CE) nuscle fibres and 0.34/μm2 for the nonjunctional sarcolemmas of slow-twitch soleus (control SOL, CS) muscle fibres. After cross-innervation between the fast-twitch EDL and slow-twitch SOL muscle fibres by slow and fast muscle merves respectively for three months, the mean density was 0.45/μm2 for the nonjunetional sarcolemmas of the operated-EDL (OE) and 8.3/μm2 for the nonjunctional sarcolemmas of the operated SOL (OS). This indicates that the cross-innervation causes a reciprocal transformation of the number and distribution of such macromolecular organizations in the electrically excitable nonjunctional sarcolemmas. 展开更多
关键词 SARCOLEMMA square array cross-innervation freeze-fracturing rat(Wistar)
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Functional Divergences of Left Dislocation Construction in English and Chinese
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作者 WANG Ji-nan 《Sino-US English Teaching》 2018年第1期14-27,共14页
This paper attempts to explore the functional divergence of LD (Left Dislocation) in English and Chinese. Through detailed analyzing, we find that LD in both languages shares only one function, the function of simpl... This paper attempts to explore the functional divergence of LD (Left Dislocation) in English and Chinese. Through detailed analyzing, we find that LD in both languages shares only one function, the function of simplifying, but it is different in other functions and there are eight more functions in Chinese than in English. The interface study of LD in the two languages leads to the implications: The connections between syntactic form and discourse function are language-specific and arbitrary, and LD serves a wide variety of discourse functions and is motivated by a range of discourse circumstances 展开更多
关键词 left dislocation (LD) discourse function syntactic discouse interface
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Develope Monoclonal Antibody against Foot-and-mouth Disease Virus A Type
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作者 Tong Lin Jing Li Jun-jun Shao Guo-zheng Cong Jun-zheng Du Shan-dian Gao Hui-yun Chang 《Virologica Sinica》 SCIE CAS CSCD 2011年第4期273-278,共6页
In order to develop an anti-FMDV A Type monoclonal antibody (mAb), BABL/c mice were immunized with FMDV A type. Monoclonal antibodies (mAbs) 7B 11 and 8H4 against Foot-and-mouth disease virus (FMDV) serotype A w... In order to develop an anti-FMDV A Type monoclonal antibody (mAb), BABL/c mice were immunized with FMDV A type. Monoclonal antibodies (mAbs) 7B 11 and 8H4 against Foot-and-mouth disease virus (FMDV) serotype A were produced by fusing SP2/0 myeloma cells with splenocyte from the mouse immunized with A/AV88. The microneutralization titer of the mAbs 7Bll and 8H4 were 1024 and 512, respectively. Both mAbs contain kappa light chainS, the mAbs were IgG1. In order to define the mAbs binding epitopes, the reactivity of these mAbs against A Type FMDV, were examined using indirect ELISA, the result showed that both mAbs reacted with A Type FMDV. These mAbs may be used for further vaccine studies, diagnostic methods, prophylaxis, etiological and immunological research on FMDV. Characterization of these ncindicated that prepared anti-FMDV A mAbs had no cross-reactivity with Swine Vesicular Disease (SVD) or FMDV O, Asial and C Type antigens. Their titers in abdomen liquor were 1:5×10^6 and 1:2×10^6, respectively. 7B 11 was found to be of subtype IgGb 8H4 was classified as IgG2b subtype. The mAbs prepared in this study, are specific for detection of FMDV serotype A, and is potentially useful for pen-side diagnosis. 展开更多
关键词 Foot-and-mouth disease virus (FMDV) A Type Monoclonal antibody (mAb) Neutralizing activity
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