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181.
当前,铁路各既有线6502电气集中系统大、中、小站控制台的报警音响,全是由电铃来实现。这些电铃从功能上大致分为以下几种:①上、下行闭塞电铃;②上、下行接近电铃;③组合架上熔丝报警电铃;④站内信号机断丝报警电铃;⑤区间信号机断丝报警电铃;⑥挤岔报警电铃;⑦主、副电源转换报警电铃;⑧信号关闭报警电铃;⑨上、下行道口遮断信号机报警电铃等。另外,复线自动闭塞区段,还有上逆、下逆接近电铃; 相似文献
182.
三种中药钙拮抗剂对家兔急性降压实验的比较 总被引:1,自引:0,他引:1
麻醉家兔急性降压实验表明,三种中药钙拮抗剂汉防己甲素、异紫堇啡碱和川芎嗪,均能降低血压并减慢其心率。三药降压效力为汉防己甲素>异紫堇啡碱>川芎嗪。而汉防己甲素与异紫堇啡碱等量合用,降压效果明显增强。 相似文献
183.
184.
ABSTRACTThis paper integrates empty container reposition with container shipping network design considering the container life stages. A mixed-integer linear programming model is built to determine the liner shipping network, the initial launch ports of new containers, the ports for scrapping obsolete containers, the empty container reposition scheme and the containers of different life stages being used for a specific voyage. A case study is done by taking liner shipping among China, Japan and South Korea, Southeast Asia, Europe and the US as an example. The results show that over 93% of new containers are put into use in China while 63% of old containers are scrapped in Europe or the US, and 73% of containers used for packing cargoes from China to the US are those at the Decline Stage or the Exit Stage. 相似文献
185.
The asymmetric deformation and eccentricity problems of near hemispherical diaphragm under the uniform surface load are quantitatively
characterized in the paper. The analysis is based on a 3D finite element analysis (FEA) model established according to elastic-plasticity
and large displacement nonlinear finite element method. Besides, the deformation experiments are taken to validate the reliability
of FEA model which shows that the simulation results are in good agreement with the experimental results. Then, three angle
parameters, deflection angle β, circumvolving angle θ and distributing angle γ, are introduced and expressed to characterize the asymmetric deformation and eccentricity quantitatively. According to the
angle parameters, the inversion processes of uniform thickness diaphragm and varying thickness diaphragm are calculated respectively.
The inversion process of varying thickness diaphragm is much steadier than that of uniform thickness diaphragm. The present
results show that the asymmetric deformation process can be characterized by curve of three angle parameters (β, θ, γ) exactly, the degrees of eccentricity can be indicated by the final value of deflection angle and the eccentricity position
can be characterized by the final values of the three angle parameters. 相似文献
186.
The performance of vacuum arc remelting (VAR) ingot depends largely on ingot structure and chemical uniformity, which are
strongly influenced by molten pool profile that is influenced by VAR process. To better understand the effect of remelting
current on molten pool profile of titanium alloy ingot during VAR process, a 3D finite element model is developed by the ANSYS
software. The results show that there are three remelting stages during VAR process when the remelting current is 2.0 kA.
The molten pool depth increases gradually from 30 to 320 s, then the change of molten pool depth is very small during the
steady state stage from 320 to 386 s, and lastly the molten pool depth becomes shallow after 386 s. The melting rate and temperature
of superheat increase with the remelting current increasing, which leads to the augment of molten pool volume. In the end,
the total remelting time and steady state molten pool time decrease with the melting current from 1.6 to 2.8 kA. 相似文献
187.
通过对上海域市轨道交通和部分提速线路的轨面短波不平顺进行现场实测,在对测试数据进行平稳性检验的基础上进一步分析了轨面短波不平顺的幅值分布特性,采用BS ENISO3095对轨面平顺度进行了分析和评价.研究表明,轨面短波不平顺幅值总体上满足显著性水平为0.05的平稳性检验要求,轨道交通1号线、2号线、3号线及沪宁线和沪昆... 相似文献
188.
客货分离道路系统研究 总被引:1,自引:0,他引:1
该文通过对当前我国道路交通现状的深入分析,确定当前制约我国道路交通系统和社会协调发展的关键环节,提出客货分离道路交通系统设计概念,可以有效地缓解城市现有交通问题,提高道路交通安全性、提高道路的利用率、降低道路建设工程投资、提高交通运输的现代化管理水平、促进城市交通一体化发展。其成果对指导城市用地布局建设,推动道路交通系统与城市的快速、高效、协调发展,具有重要意义。 相似文献
189.
190.
以合武客运专线动检车实测轨道不平顺数据为统计样本,采用轨道不平顺变化率和线性插值方法以及经验模态分解法对轨道不平顺异常值和趋势项进行处理,并运用经典周期图法对统计样本进行空间谱估计,同时采用最小二乘法对轨道不平顺功率谱进行拟合。研究结果表明,不平顺功率谱谱线普遍低于美国6级谱,在长波波段能量较低,但存在周期性成分,同时温度力对无缝线路影响显著。缓和曲线与圆曲线的分析结果都表明内轨平顺状况优于外轨。 相似文献