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近年来,国内和国际的交流日益增多,DCN(数字会议系统)和电话电视会议的发展非常迅速,并逐渐在政府机关单位、会议中心和企业集团中广泛应用。会议讨论系统、同声传译系统、扬声器系统、录放音系统、拾音系统,以及表决系统都包含于会议系统中。这类系统在进行视频交流的同时,通过电脑控制和存储会议中的所有资料。本文主要阐述了电视电话会议系统的组成以及系统中音频、视频、DCN等系统设备的功能描述、操作设置等内容。 相似文献
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本文以履带式汽车虚拟驾驶训练系统为背景,研究驾驶训练系统的虚拟现实和视景仿真等技术,设计了包括动力仿真系统,视景仿真系统,音响仿真系统,仪表仿真系统和测评仿真系统等子系统所组成的履带式汽车虚拟驾驶训练系统,并讨论了各个子系统的设计功能和技术原理。 相似文献
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在多级压力源切换系统中,存在系统节能机理不明晰以及系统关键参数选取缺乏依据的问题。基于此,本文通过建立多级压力源切换系统和传统负载口独立阀控系统的能耗数学模型,对多级压力源切换系统的节能效果进行理论推导;搭建两系统的仿真模型,将两系统在给定工况下进行对比,对多级压力源切换系统的节能效果进行仿真研究;通过绘制系统位移跟随误差和节能功率的曲面图,分析总结了影响系统能耗和控制特性的主要因素,确定了系统的主要工作参数——阀芯位移比和中间压力等级的取值大小。研究结果为提高多级压力源切换系统的系统性能和优化系统参数提供了分析依据。 相似文献
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阐述了电力供配电系统的工作接地,保护接地和防雷接地三种接地方式的特点及作用,重点分析了保护接地TN系统(TN-C系统、TN-S系统和TN—C—S系统)、TT系统和IT系统的原理及优缺点。明确了接地电阻的要求,得出了正确选择和安装接地方式的重要性。 相似文献
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《中国新技术新产品》2011,(1):I0008-I0008
<正>由何开浩研发的塔式太阳能热发电系统的聚光瞄准装置有聚光系统,吸、换热系统,储热系统和发电系统四部分组成。其中,聚光系统包括反射镜、支撑结构、传动装置和跟踪控制系统。塔式太阳能热发电系统采用光-热- 相似文献
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现在的新建办公楼弱电综合信息系统一般都要包括办公电话系统、音视频会议系统、调度系统、保密系统、通信系统,以及为这些信息业务提供网络支持的传输系统和电源系统,如图1所示。同时,系统中要引入新技术新设备,增加、强化和完善系统功能,为办公信息化以及生产指挥调度智能化发挥了重要的作用。 相似文献
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提出了二级再生氨一盐系统(系统1)的改进系统(系统2和系统3),将系统1和系统2、系统3的热力学模拟结果进行了分析比较。两种改进系统的最高操作压力都在0.2MPa以下,远低于系统1的最高操作压力。改进系统的操作性能都有显著提高,系统2的COP值升高幅度和循环倍率降低幅度都是最大,烟效率也有显著提高;系统3的COP值也有较大的提高,炯效率提高最为显著,但循环倍率反而较系统1明显升高。系统1和系统2均可在加热温度低于160℃时稳定操作,而系统3则适于加热温度高于160℃的情况。当被冷却系统需要在0℃以下的恒定温度下提供冷量时,适用系统1制冷。当物料需要在冷却水冷却后再逐渐降温至所需要的温度时,适用改进后的系统。 相似文献
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办公自动化系统作为电子政务系统的重要组成部分,需要不断更新以适应和服务新的电子政务的发展趋势和新的需求。办公自动化系统的发展必然会带来新旧系统数据迁移,从平滑过度策略、迁移过程、系统数据测试和系统切割方面对四川省交通厅办公自动化系统数据迁移进行研究,提出相应的策略和方案,同时对一些常见的问题进行讨论。 相似文献
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Weak link (WL)/strong link (SL) systems constitute important parts of the overall operational design of high-consequence systems, with the SL system designed to permit operation of the system only under intended conditions and the WL system designed to prevent the unintended operation of the system under accident conditions. Degradation of the system under accident conditions into a state in which the WLs have not deactivated the system and the SLs have failed in the sense that they are in a configuration that could permit operation of the system is referred to as loss of assured safety. The probability of such degradation conditional on a specific set of accident conditions is referred to as probability of loss of assured safety (PLOAS). Previous work has developed computational procedures for the calculation of PLOAS under fire conditions for a system involving multiple WLs and SLs and with the assumption that a link fails instantly when it reaches its failure temperature. Extensions of these procedures are obtained for systems in which there is a temperature-dependent delay between the time at which a link reaches its failure temperature and the time at which that link actually fails. 相似文献
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Xia Tian 《Inverse Problems in Science & Engineering》2016,24(7):1205-1214
Given three eigenvalues and their corresponding eigenfunctions of the beam. It is assumed that the total mass of a beam is known. The problem of constructing the physical elements of the system from the known data is considered. The sufficient conditions for the construction of a physical realizable system with positive continuous variable: bending rigidity function and density function are established. If these conditions are satisfied, the system may be constructed uniquely. 相似文献
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普通热泵空调系统在超低温环境下制热衰量减大,难以满足中国北方冬季取暖需求,在一套普通R410A风冷冷(热)水机组上分别对喷液技术和EVI技术进行超低温环境测试对比。结果表明,喷液系统和EVI系统在低温和超低温下具有较好的制热量及制热能效的提升,并且可以解决普通热泵在超低温环境下的应用问题,同时R32的热物理性质与R410A基本相同,提出在低温风冷冷(热)水机组上使用R32替代R410A的设想。 相似文献
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Firdaus E. Udwadia 《International Journal of Engineering Science》2012,50(1):79-100
This paper presents the investigation of the longitudinal motions of a bar subjected to viscous boundary conditions at each end. These viscous boundary conditions can also be thought of in terms of boundary feedback control. The system is not self-adjoint and for certain parameter regimes exhibits super-stable, super-unstable, and undamped behavior. Closed form solutions to the response of the system subjected to initial conditions and external excitation are obtained. The physical origins of the super-stable and super-unstable behavior are investigated and their intricate connectedness with the continuum model used to understand the dynamics is explained. The issue of discretization of the continuous system is discussed and it is shown that the continuum assumption bestows certain features to the response of the system that no finite dimensional approximation can qualitatively capture. Computational results corroborating the theoretical analysis are presented. 相似文献
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In this paper, we present a new fractional theory of dynamics, i.e., the dynamics of generalized Hamiltonian system with fractional derivatives (fractional generalized Hamiltonian mechanics). Based on the definition of Riemann–Liouville fractional derivatives, the fractional generalized Hamiltonian equations are obtained, the gradient representation and second-order gradient representation of the fractional generalized Hamiltonian system are studied, and then the conditions on which the system can be considered as a gradient system and a second-order gradient system are given, respectively. By using the method and results of this paper, the conditions under which a fractional generalized Hamiltonian equation can be reduced to a generalized Hamiltonian equation, a fractional Hamiltonian equation and a Hamiltonian equation are given, respectively, and then the existing conditions and their form of gradient equation and second-order gradient equation are investigated. Finally, an example of a fractional dynamical system is given to illustrate the method and results of the application. 相似文献
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将硅膨胀阀应用于电动汽车空调系统,对比H型热力膨胀阀系统与硅膨胀阀系统的制冷量和能效比等性能参数。试验结果表明,在各运行工况下,硅膨胀阀系统平均制冷量及能效比较H型热力膨胀阀系统均有大幅提高;硅膨胀阀在对多变工况的响应速度上表现优秀,尤其适合于工况波动剧烈的电动汽车空调系统。 相似文献
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研究了一类具有线性不可控模态的非线性系统平稳分岐解的镇定问题.假定系统参数不可测量.基于不变流形理论,从原非线性系统导出了一个一维的简化方程.从简化方程的性质导出了原系统能分岐镇定的一些充分和必要条件.并举例说明了此方法的有效性. 相似文献