水体注入器皿的动力学粒子建模研究

基于物理过程的建模方式能够真实地模拟流体的运动状态,表现出很好的模拟效果,但对不同的流体形态以及同一种流体的不同细节状况,所涉及到的细节属性参数也不同,通常存在着较大的建模差异。首先对流体动力学的流体模拟原理进行了分析,在此基础上对水体倒入4种不同形状容器的流体动力学平滑粒子模型进行了研究,提出一种基于分块的邻居粒子搜索方法,以提高在空间均匀网格上对邻居粒子的搜索速度,给出了流体与器皿碰撞的判断与响应方法。最后通过水体注入不同器皿的仿真试验验证了所建立模型的有效性。     

An adaptive learning regulator for uncertain minimum phase systems with undermodeled unknown exosystems

The design of an adaptive learning regulator is addressed for uncertain minimum phase linear systems (with known bounds, known upper bound on system order, known relative degree, known high frequency gain sign) and for unknown exosystems (with unknown order, uncertain frequencies). On the basis of a known bound on system uncertainties and a known bound on the modeled exosystem frequencies, a new adaptive output error feedback control algorithm is proposed which guarantees exponential convergence of both the output and the control input errors into residual bounds which decrease as the exosystem modeling error decreases. Exponential convergence of both errors to zero is obtained when the regulator exactly models all exosystem excited frequencies, while asymptotic convergence of both errors to zero is achieved when the actual exosystem is overmodeled by the regulator. The new algorithm generalizes existing learning controllers since, in the case of periodic references and/or disturbances, the knowledge of the period is not required.     

电弧炉电极调节系统的离散时间自适应控制

提出了电弧炉电极调节系统的数学模型 ,并在此模型基础上推导出了离散时间模型参考自适应控制规律。然后根据推导出的自适应律对电弧炉系统进行仿真研究 ,仿真结果表明自适应控制系统具有较好的跟踪性能。     

A Framework for Providing User Level Quality of Service Guarantees in Multi-Class Rate Adaptive Systems

The problem of channel sharing by rate adaptive streams belonging to various classes is considered. Rate adaptation provides the opportunity for accepting more connections by adapting the bandwidth of connections that are already in the system. However, bandwidth adaptation must be employed in a careful manner in order to ensure that (a) bandwidth is allocated to various classes in a fair manner (system perspective) and (b) bandwidth adaptation does not affect adversely the perceived user quality of the connection (user quality). The system perspective aspect has been studied earlier. This paper focuses on the equally important user perspective. It is proposed to quantify user Quality of Service (QoS) through measures capturing short and long-term bandwidth fluctuations that can be implemented with the mechanisms of traffic regulators, widely used in networking for the purpose of controlling the traffic entering or exiting a network node. Furthermore, it is indicated how to integrate the user perspective metrics with the optimal algorithms for system performance metrics developed earlier by the authors. Simulation results illustrate the effectiveness of the proposed framework.

Application of the modified Taylor approximation

In this paper we introduce and describe a new scheme for the numerical integration of smooth functions. The scheme is based on the modified Taylor expansion and is suitable for functions that exhibit near-sinusoidal or repetitive behaviour. We discuss the method and its rate of convergence, then implement it for the approximation of certain integrals. Examples include integrands involving Airy wave, Bessel, Gamma, and elliptic functions. The results, from the data in the tables, demonstrate that the method converges rapidly and approximates the integral as well as some well-known numerical integration methods used with sufficiently small step sizes.     

龙滩水电站励磁系统国产化改造及新技术应用

从巨型机组励磁系统设备维护的经济性、技术服务的快捷性、设备升级改造的方便性以及对核心控制技术的可控性等方面考虑,龙滩水电站机组励磁系统的国产化改造显得尤为迫切。对龙滩水电站700MW机组励磁系统进行了国产化改造,介绍了改造实现方法和相关新技术的应用。     

基于P89V51的高精度工频耐压测控系统的设计

从软硬件和试验方法等方面介绍了一种基于P89V51单片机的高精度工频耐压测控系统.该测控系统采用模块化设计,包括实时数据采集与显示模块、数字调压器模块、故障报警模块、上位机通讯模块和保护控制模块.整个系统具有精度高、体积小、安全性高和操作方便等优点.     

民用电网谐波电流检测方法及仿真研究

针对民用电网中存在的电压不稳、三相不平衡和中线电流大等问题,在传统的ip-iq法基础上,采用对称分量法和零序电流分离法研究电流中的零序分量问题,并结合PI调节器建立数学模型对其谐波、基波负序和零序电流进行了实时检测。结果表明,该方法可准确地检测出电网电流中含有的谐波、基波负序和零序电流,且检测精度高、实时性好。     

硼酸镧钙中三价铕离子的辐射跃迁参数

采用高温固相法合成了三价铕离子掺杂的硼酸镧钙(La2CaB10O19:Eu3+)荧光粉,XRD测试表明样品属单斜晶系。La2CaB10O19:Eu3+可被近紫外和蓝光LED有效激发,发射主峰位于617nm处,对应铕离子的5 D0!7F2跃迁。Judd-Ofelt强场参数表明,在La2CaB10O19:Eu3+样品中三价铕离子周围环境具有较强的共价性和反演非对称性。计算得5 D0!7FJ(J=1,2,4)的自发辐射跃迁概率分别为80.95、155.46和41.21s-1,最大受激发射截面分别为3.05×10-22、7.41×10-22和3.00×10-22cm2。有效的红光发射表明,La2CaB10O19:Eu3+荧光粉可以作为红色荧光色彩调节剂应用于白光LED。     

金矿矿石可选性试验研究

对我国某金矿矿石进行浮选可行性试验研究,通过研究得到了精矿石粗选和精选的最佳工艺数据,为该矿山选厂设计提供了必要的浮选试验数据。