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二乘二取二安全控制平台包括二乘二取二逻辑运算单元,二取二开关量输入、输出单元,人机接口单元。逻辑运算单元由2块独立的CPU板构成二取二结构,2块CPU板通过板上硬件同步单元实现信息交互和同步,在软件上独立进行运算结果的比较,并通过第三方硬件比较器实现2块CPU板总线数据的实时校核,保证了双CPU比较的正确性。输入单元和输出单元中均设计了双套智能处理器,采用动态控制方式,在出现硬件故障时可导向安全侧。其中输入单元对现场继电器前后接点进行采集,输出单元输出采用双断方式,可实时检测板外混电情况。 相似文献
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由于IPv4网络的广泛影响,其向IPv6网络的过渡需要很长一段时间.在此期间,IPv4协议和IPv6协议长期共存,过渡网络的管理是亟待解决的重要问题.针对此问题,分析了拓扑发现的一般方法和在IPv4/IPv6混合网络环境下拓扑发现需要解决的问题,提出了一种解决方案.方案综合了SNMP网络管理模式和traceroute6网络管理技术,解决了匿名路由器和交叉链路的发现等问题.实验表明该方案工作效率较高,结果令人满意. 相似文献
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本文结合现有海洋平台电力分配系统,提出了一种环形配电网络与直流配电技术相结合的新型配电网络,并分析这种新型配电网络的优点和关键技术。 相似文献
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Experimental tests were conducted to evaluate the hydrodynamic performance of an L-type podded propulsor in straight-ahead motion and off-design conditions using an open-water measuring instrument developed by the authors for podded propulsors, a ship model towing tank, and under water particle image velocimetry (PIV) measurement systems. Under the three types of conditions, the main parameters of an L-type podded propulsor were measured, including the propeller thrust and torque, as well as the thrust, side force, and moment of the whole pod unit. In addition, the flow field on the section between the propeller and the strut was analyzed. Experimental results demonstrate that the dynamic azimuthing rate and direction and the turning direction affect the forces on the propeller and the whole pod unit. Forces are asymmetrically distributed between the left and right azimuthing directions because of the effect of propeller rotation. The findings of this study provide a foundation for further research on L-type podded propulsors. 相似文献
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Dynamic compaction (DC) is an efficient soil improvement technique. The previous numerical studies mainly focus on the soil response of single location tamping, but ignore the soil compaction degree under multilocation tamping. In this study, a numerical investigation of multi-location tamping in granular soils is carried out using three-dimensional (3D) finite element model (FEM). The behaviors of the granular soils are described by means of the viscoplastic cap model. The constitutive relationship of the soils is implemented into LS-DYNA and is integrated with 3D FEM for numerical investigation. Then utilizing the field data from the previous studies, we investigate the soil compaction degree at different stages by a case of two basic patterns, and discuss the cause of soil response. Lastly, we evaluate the effect of construction parameters on soil compaction. The simulation results show that the previous tamping affects the soil compaction degree beneath the adjacent tamping location, and the effect is greater near the side of previous location. Meanwhile, the soil compaction degree around the existing tamping crater weakens due to the adjacent tamping. Moreover, the rational selection of DC construction parameters can improve the soil compaction degree, and some hints on the effect of soil compaction are given. 相似文献
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采用单克隆抗体、间接致敏红细胞花环试验法对复发性口疮(Recurrentaphthous ulcer,RAU)、胃癌及系统性红斑狼疮(System ic lupus erythem atosus,SLE)患者外周血WuT3、WuT4、WuT8 及T4/T8 比值进行检测。结果:胃癌患者WuT3、WuT4 低于对照组( P< 0.05),WuT8 高于对照组,T4/T8 比值明显低于对照组( P< 0.001)。SLE组患者WuT8 较对照组低下,T4/T8 比值增高( P< 0.05)。RAU组患者WuT3 低于对照组,WuT8 高于对照组,T4/T8 比值下降( P< 0.05)。认为:①胃癌的发生是机体总的细胞免疫处于低下无能状态,不能对肿瘤进行正常的免疫监视及免疫应答。②SLE的发病与WuT8 功能降低有关,其导致自身反应细胞发生脱抑制而功能亢进。③RAU 的发生是因WuT8 细胞功能增强,致使Tc细胞的作用增强,其直接攻击粘膜靶细胞造成粘膜坏死、溃疡 相似文献