振动场作用下聚合物熔体在异型材挤出口模内的充填流动分析

利用ANSYS软件对受口模入口处周期性振动的压力驱动的非牛顿幂律聚合物熔体在“L”形异型材挤出口模内的充填流动进行了三维等温数值模拟,求得了压力和速度随时间和沿路径的变化曲线,并因此总结出了振动参数对充填流动的影响规律.结果表明,速度和压力的振动均沿挤出方向逐渐衰减,入口压力的低频高幅振动有利于充填过程的稳定.     

超微粒子的量子阻尼振动理论

根据SU(1,1)Lie代数,建立超微粒子的量子阻尼振动理论,得到超微粒子量子阻尼振动系统的能级和波函数。     

受BGP策略影响的路由稳定性仿真数据分析

BGP是一个基于策略的路由协议，目前，由于BGP策略所引发的路由振荡在Internet中非常普遍，给网络稳定性健壮性都带来了很多负面的影响。网络仿真在路由稳定性研究中充当着相当重要的角色。用网络仿真的方法来研究和分析影响BGP路由稳定性的因素，是一个非常科学实用的研究方法和途径。     

Characteristics of heating process in microwave applicators with elements in periodic motion

Moving elements have been widely used in microwave applicators to improve heating uniformity. However, elements in periodic motion can lead to temperature oscillations in the process of heating. In this case, the processed samples are difficult to reach target temperature and the control system may also become unstable. Aiming at overcoming these problems, we investigate the temperature response of the heating process in microwave applicators with elements in periodical motion in this article. By modeling periodical motion as a periodical heat source, the temperature characteristics can be obtained by solving the heat transfer equation with eigenfunction expansions. The results show that the amplitude of temperature oscillations decreases with angular velocity of the element's motion, which is verified by experiments. It means that temperature oscillations can be reduced by increasing the element's velocity, which is helpful to improve the heating performance in microwave applicators.     

灯泡贯流式机组运行稳定性分析

电力系统自动发电控制（AGC）投入运行后,发电机组的运行方式由惯有的静态控制转变为动态控制,这对洪江水电站贯流式机组影响明显。运行环境变化后,该机组振动大、设备问题频繁。抓住机组稳定性的课题,从机组自身的结构特点着手,按静态、动态两种控制方式展开分析,阐述了贯流式机组运行稳定性“静态控制性能良好、动态控制相对较差”的论点,并进行了理论和现场实验的深化论证。     

横向液货补给索道-软管的强迫振动数值分析

考虑索道倾斜角度、鞍座位置、索道跨距等因素影响,对舰船横向液货补给索道-软管动力学问题进行研究.基于静力学原理得到各鞍座位置索道及软管受力情况,进而将横向液货补给系统索道-软管动力学问题简化为具有多个集中质量索道系统的动力学问题.基于Galerkin原理,对偏微分动力学模型进行高阶模态截断,并对典型工况下系统动力学特性进行分析.研究表明,系统存在周期、混沌等典型复杂动力学特性.重点分析了索道跨距、阻尼等对系统动力学特性的影响.     

多通道生物压电传感芯片微分析系统设计

为了满足石英传感阵列信号采集的要求,设计了一种基于虚拟仪器技术的多通道生物压电传感芯片微分析系统。该系统硬件部分由信号处理电路、数据采集卡和计算机等组成;软件部分采用图形化编程语言LabVIEW设计。利用该系统分析溶液电导率与石英传感芯片谐振频率偏移的关系。实验结果表明:该系统能够实现对频率信号的实时测量,并能实现数据的自动采集、处理、保存;可进一步用于生物大分子的检测。     

基于历史数据挖掘和劳斯判据的某火电机组功率振荡机理分析

当汽轮机阀门流量特性恶化时,会引起发电机组功率振荡,进而可能引发电网低频振荡。本文以发生过功率振荡的某660MW超临界机组为例,通过数据挖掘和劳斯稳定判据原理,挖掘机组历史数据得到实际阀门流量特性,同时建立有功调节系统综合模型,定性、定量地分析汽轮机阀门流量特性对系统稳定性的影响,计算得到使系统失稳的阀门流量特性曲线曲率（k）的临界值为3.3438,当k大于临界值时,系统将失稳。同时,通过数据挖掘分析发现机组在92.7%～96.6%综合阀位指令段的阀门流量特性恶化严重,k值最大达到了7.771,远大于临界值,这是导致机组在该指令区间内发生多次功率振荡事件的根本原因。本文的分析方法对今后类似功率振荡事件的分析诊断,有一定的借鉴作用。     

迭代学习控制用于StatCom阻尼区域间振荡的研究

ＳｔａｔＣｏｍ一般安装在长距离输电线路上,用于提高电力系统的稳定性,阻尼振荡,提高电压控制的精度及系统的传输能力。     

A new methodology for identification of critical lines using damping sensitivity analysis

When an inter-area mode dominates a low-frequency oscillation in a stressed condition, control of the active power flow of interface lines, with compensating devices, can effectively reduce the electromechanical power oscillations. In general, interface lines in which inter-area oscillations are large are considered to be good locations for installation of compensating devices. A sensitivity analysis with respect to change in active power flow can provide an important factor in electric power system operation. This paper proposes a new methodology to calculate the damping sensitivity with respect to change in active power flow, which can be useful for accurate selection of critical lines from the viewpoint of small-signal stability. In the proposed methodology, a damping sensitivity index is used to select the critical lines to damp power system oscillations. This paper describes how to derive the damping sensitivity for the selected mode and illustrates an example applying the proposed algorithm to a simple two-area system and the New England 39-bus test system.