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61.
本文叙述了智能网的业务管理系统所实现的3种功能:业务管理功能,网络管理功能和业务管理访问功能,还介绍了业务管理和网络管理之间的关系,SMS的集中式和分布式两种体系结构及业务管理功能的设计方法和进一步研究方向。 相似文献
62.
The causes of lightning outage are subdivided into direct lightning strokes and induced lightning strokes, which are identified by the characteristics of the lightning overvoltage. In the past, lightning protection devices were directed mainly toward the latter, and attention has been focused on the installation of lightning protection devices, ground wires, and reinforcement of insulators. However, lightning outages continue to occur. Thus it is extremely important to clarify the fault characteristics of lightning surges and to study the effectiveness of various lightning protection devices by considering both direct lightning stroke and induced lightning stroke in order to prevent lightning outage in the future. In this research, the electromagnetic transients program (EMTP) has been applied to the direct lightning stroke, and the induced lightning outage analysis program for multiple conductor systems has been applied to the induced lightning stroke to study the effectiveness of lightning protection devices provided by combination of various lightning protection devices. The most effective lightning protection schemes are analyzed and evaluated based on verification tests on the full scale models as well as economic considerations. 相似文献
63.
N Kayansayan 《International Journal of Refrigeration》1996,19(3):197-207
The paper describes an effectiveness-NTU design method of bayonet-tube evaporators and condensers. Including the effect of the wall superheat on the shell-side film coefficient, and using an energy balance on the tube, differential equations for the steady-state fluid temperatures are formulated. Because of the nonlinear nature of the governing equations, the fourth-order Runge-Kutta method is employed to the solution of the finite difference equations. The results are iterated with the combination of integration techniques. An upper bound to the numerical error being ±5% the fluid temperature distribution as well as the exchanger effectiveness are determined, and presented as a function of the Hurd number, the number of heat transfer units and the flow arrangement. For flow entering through the inner tube, the temperature distribution displays the occurrence of a minimum at a point other than the tube-tip of the exchanger. In an extension of the analysis, an effort is made to illustrate the deviation of the results obtained by uniform film coefficient from the present study, and the differences are outlined. 相似文献
64.
Kwang Soo Lee In Soo Park & Dong Sun Lee 《International Journal of Food Science & Technology》1996,31(1):7-13
The aim of this study was to design a modified atmosphere package for a mixed vegetable salad consisting of 75 g of cut carrot, 55 g of cut cucumber, 20 g of sliced garlic and 50 g of whole green pepper. Respiration data of all the components were combined with film permeability data to predict package atmospheres and design optimal packages for experimental testing for improved shelf-life of the produce. The optimal package avoided minimum O2 and maximum CO2 tolerance limits, and chilling injury temperatures for any component. A pouch form package made of 27 mm low density polyethylene developed a modified atmosphere of 2.0–2.1% O2 and 5.5–5.7% CO2 , which was beneficial for all components and provided better quality retention than other test packages. 相似文献
65.
Three distinct stages of kink band formation and propagation exist in ductile matrix composites subjected to compressive loading. These stages are called incipient kinking, transient kinking and kink band broadening. Each stage involves a different deformation mode. The mechanics governing each stage are discussed. Incipient kinking, where the peak load is attained, and kink band broadening, where the load attains a steady-state, are important in structural design. Two design philosophies are presented. References to pertinent literature are made throughout. 相似文献
66.
变结构变参数设计方法及其在机械CAD中的应用 总被引:4,自引:0,他引:4
提出了一种新颖的机械结构设计思想-变结构变参数设计方法,并结合实例,阐述了变结构变参数设计的概念、原则、实施措施和意义。由此对I-deas软件包进行了二次开发,编制了发动机曲轴专用CAD软件程序,并用某型号发动机曲轴进行了验证。 相似文献
67.
Inverse surface design problems from light transport behavior specification usually represent extremely complex and costly processes, but their importance is well known. In particular, they are very interesting for lighting and luminaire design, in which it is usually difficult to test design decisions on a physical model in order to avoid costly mistakes. In this survey, we present the main ideas behind these kinds of problems, characterize them, and summarize existing work in the area, revealing problems that remain open and possible areas of further research. 相似文献
68.
Repetitive processes are a distinct class of 2D systems (i.e. information propagation in two independent directions) of both systems theoretic and applications interest. They cannot be controlled by direct extension of existing techniques from either standard (termed 1D here) or 2D systems theory. In this paper, we exploit their unique physical structure to show how two term, i.e. proportional plus integral (or PI) action, can be used to control these processes to produce desired behavior (as opposed to just stability). 相似文献
69.
70.
清代皇家园林规划设计控制的量化研究——以圆明三园、清漪园为例 总被引:1,自引:0,他引:1
本文通过量化分析探索了清代皇家园林规划设计的控制规律及相关理论。 相似文献