基于轨道电路解决站内分路不良方案的研究

本文首先分析了我国站内轨道电路分路不良产生的原因，然后在分析国外解决分路不良方案的基础上，结合我国实际情况，提出了几种解决分路不良切实可行的技术方案。     

畸变电源作用于二阶网络的研究

本文用大量实验数据和图片真实记录了畸变电源作用于二阶网络对电流冲击的影响,并通过计算给予了理论上的验证,同时还进一步分析计算了电流冲击与网络参数的关系.     

THEORETICAL ANALYSIS OF CHARGE ACCUMULATION ON INSULATOR SURFACE UNDER IMPULSE VOLTAGE IN A GAS INSULATED SWITCHGEAR

Ｉｎｓｕｌａｔｉｎｇｓｐａｃｅｒｓｓｕｐｐｏｒｔｉｎｇｔｈｅｈｉｇｈｖｏｌｔａｇｅｃｏｎｄｕｃｔｏｒｉｎｃｏｍｐｒｅｓｓｅｄｇａｓｉｎｓｕｌａｔｅｄｓｙｓｔｅｍｓｐｌａｙａｎｉｍｐｏｒｔａｎｔｒｏｌｅｉｎｄｅｔｅｒｍｉｎｉｎｇｔｈｅｏｖｅｒａｌｌｓｉｚｅｏｆｇａｓｉｎｓｕｌａｔｅｄｓｗｉｔｃｈｇｅａｒ (ＧＩＳ) .Ｄｕｅｔｏｖｅｒｙｈｉｇｈｓｕｒｆａｃｅｒｅｓｉｔｉｖｉｔｙ ,ｅｌｅｃｔｒｏ ｓｔａｔｉｃｃｈａｒｇｅｓｍａｙｂｅａｃｃｕ ｍｕｌａｔｅｄａｎｄｈｅｌｄａｔｄｉｅｌｅｃｔｒｉｃｉｎｔｅｒｆ…     

可控整流直流电动机调速系统主回路临界电感量与滤波电感量的计算问题

研究了三相半波可控整流和三相桥式全控整流直流电动机调速系统主回路临界电感量L_(lx)和滤波电感量L_(md)的计算问题,提出以限制连续整流电流i_d在谷点以上部分的平均值(也可定义为i_d的脉动幅值)作为滤波指标,从而使L_(lx)和L_(md)的计算公式达到统一,分析了回路电阻对L_(lx)和L_(md)计算的影响。     

Recognizing frequency characteristics of gas sensor array

A novel method based on independent component analyzing （ICA） in frequency domain to distinguish the frequency characteristics of multi-sensor system is presented. The conditions of this type of ICA are considered and each step of resolving the problem is discussed. For a two gas sensor array, the frequency characteristics including amplitude-frequency and phase-frequency are recognized by this method, and cross-sensitivity between them is also eliminated. From the principle of similarity, the recognition mean square error is no more than 0.085.     

城市轨道交通信号系统采集和驱动电路雷击试验方法

通过分析城市轨道交通信号系统采集和驱动电路的工作原理,找到了雷电电磁脉冲的引入途径。结合测试标准要求,分别给出了采集电路、光控可控硅驱动电路和晶体管驱动电路等三种不同接线形式的雷击试验方法。指出了试验过程中需要注意的问题,为城市轨道交通信号采集和驱动电路的防雷设计提供合理的试验方法。     

带脉冲和时滞的二阶微分方程的稳定性

研究了带脉冲和时滞的二阶微分方程的稳定性问题。通过构造合适的Lyapunov函数,利用稳定性理论和脉冲控制方法,证明了对于不稳定的时滞二阶微分方程,可以通过加强一定的脉冲控制使其稳定。获得的结果改进和推广了前人的工作,提供的例子表明了获得结果的有效性。     

典型舱内爆炸载荷对加筋板的毁伤特性

[目的]为研究典型舱内爆炸载荷对加筋板的毁伤特性,将舱内爆炸载荷分为初始爆炸冲击波载荷和准静态气压载荷,利用有限元分析软件LS-DYNA开展爆炸载荷下固支单向加筋板毁伤特性的数值模拟.[方法]主要模拟载荷冲量相等和载荷峰值相等时固支单向加筋板的变形特性,以及加筋板分别在初始爆炸冲击波载荷、准静态气压载荷及2种载荷联合作...     

Dynamics and interactions between spot and forward freights in the dry bulk shipping market

Analyzing the interactions between spot and forward freight agreement (FFA) prices in the dry bulk shipping is important as they play a significant role for shipping companies to secure their profits and avoid potential risks in the volatile market. By applying the vector autoregression (VAR) and the vector error correction model (VECM), this paper identifies the long-run and mutual causal relationship between the spot and FFA prices on the BPI T/C and BCI C7 routes. Along with these cointegrating rates, exogenous factors such as the market demand and supply and some economic indices are also recognized as contributing variables for the dynamic movement of the spot and FFA prices. Importantly, the mean-reverting process is justified on both routes with different mechanisms. When the spot and FFA prices deviate from their equilibrium level in the short run, they will be adjusted to their long-run equilibrium more directly and clearly on the BPI T/C route than those on the BCI C7 route. It also indicates that this adjusting power has direction and size asymmetries on both routes. In addition, the impulse analysis indicates that the spot rate is more volatile than its corresponding FFA prices confronting innovations. The results of this study provide a reference to the participants in the dry bulk shipping market on the causes of fluctuation in spot and FFA prices and their interactions, which can be used to promote the risk management in the market.     

城市轨道车辆运行中纵向冲击对人体振动影响的仿真研究

建立了人体与轨道车辆振动耦合模型,并在模型基础上进行仿真研究.从仿真结果中得到车体、人体头部及人体内脏在横向、垂向和纵向上的振动响应及其能量集中的主要频率段,并从功率谱密度图得知人体头部和内脏的振动响应频率基本相同.当冲击力越大速度越高时,车体和人体所产生的响应加速度越大,但垂向和横向的响应比较小,纵向响应比较大.