凝结水精处理系统工艺流程研究——以安庆电厂凝结水精处理系统为例

对安庆电厂由武汉凯迪股份公司提供的中压凝结水精处理的高速混床和再生系统的设备、设计、工艺流程的特点进行分析研究.     

Microbes,mathematics, and models

Microbial model systems have a long history of fruitful use in fields that include evolution and ecology. In order to develop further insight into modelling practice, we examine how the competitive exclusion and coexistence of competing species have been modelled mathematically and materially over the course of a long research history. In particular, we investigate how microbial models of these dynamics interact with mathematical or computational models of the same phenomena. Our cases illuminate the ways in which microbial systems and equations work as models, and what happens when they generate inconsistent findings about shared targets. We reveal an iterative strategy of comparative modelling in different media, and suggest reasons why microbial models have a special degree of epistemic tractability in multimodel inquiry.     

营销组合理论演变的动因分析

1960年,麦卡锡创立了经典的4Ps营销组合理论。在随后的40多年历史发展中,营销组合理论发展迅速,各种理论层出不穷,6Ps、7Ps、10Ps、4Cs、4R s等学说百家争鸣。营销理念由注重短期交易关系转变为对长期交易关系的注重是营销组合理论发展的思想背景,而企业组织结构柔性化和企业交易控制权弱化则是推动营销组合理论演变的双重最终动因。     

Local reduction in physics

A conventional wisdom about the progress of physics holds that successive theories wholly encompass the domains of their predecessors through a process that is often called “reduction.” While certain influential accounts of inter-theory reduction in physics take reduction to require a single “global” derivation of one theory׳s laws from those of another, I show that global reductions are not available in all cases where the conventional wisdom requires reduction to hold. However, I argue that a weaker “local” form of reduction, which defines reduction between theories in terms of a more fundamental notion of reduction between models of a single fixed system, is available in such cases and moreover suffices to uphold the conventional wisdom. To illustrate the sort of fixed-system, inter-model reduction that grounds inter-theoretic reduction on this picture, I specialize to a particular class of cases in which both models are dynamical systems. I show that reduction in these cases is underwritten by a mathematical relationship that follows a certain liberalized construal of Nagel/Schaffner reduction, and support this claim with several examples. Moreover, I show that this broadly Nagelian analysis of inter-model reduction encompasses several cases that are sometimes cited as instances of the “physicist׳s” limit-based notion of reduction.     

Models, scientific realism, the intelligibility of nature, and their cultural significance

In this article, I will view realist and non-realist accounts of scientific models within the larger context of the cultural significance of scientific knowledge. I begin by looking at the historical context and origins of the problem of scientific realism, and claim that it is originally of cultural and not only philosophical, significance. The cultural significance of debates on the epistemological status of scientific models is then related to the question of ‘intelligibility’ and how science, through models, can give us knowledge of the world by presenting us with an ‘intelligible account/picture of the world’, thus fulfilling its cultural-epistemic role. Realists typically assert that science can perform this role, while non-realists deny this. The various strategies adopted by realists and non-realists in making good their respective claims, is then traced to their cultural motivations. Finally I discuss the cultural implications of adopting realist or non-realist views of models through a discussion of the views of Rorty, Gellner, Van Fraassen and Clifford Hooker on the cultural significance of scientific knowledge.     

粉体材料颗粒堆积状态对收缩的影响

为提高粉体材料颗粒堆积状态,获得更佳工作性能,各研究人员致力于改善水泥颗粒粒径分布或掺加不同粒径粉体材料。本文通过对不同水泥品种、不同矿物掺合材进行堆积密度及流动度试验结合粉煤灰和硅粉化学收缩实验,从用水量及孔隙结构两方面阐明颗粒堆积状态对收缩的影响。     

电力系统仿真软件DIgSILENT简介

本文介绍了电力系统仿真软件DIgsILENT／PowerFactory的特点。根据软件自带的电力系统元件的模型库和简明的动态仿真语言DSL，用户在搭建电力系统模型时更为方便快捷，反映了该软件在大型电力系统仿真方面的优越性。     

30KV高压开关电源在雷达发射机中的应用

本文主要介绍了一种适用于大功率真空管发射机的高压电源设计方案,分析了其工作原理,并对防冲电路、零电压全桥逆变谐振电路、高性能控制电路等关键电路进行了论述。     

Representing with imaginary models: Formats matter

Models such as the simple pendulum, isolated populations, and perfectly rational agents, play a central role in theorising. It is now widely acknowledged that a study of scientific representation should focus on the role of such imaginary entities in scientists’ reasoning. However, the question is most of the time cast as follows: How can fictional or abstract entities represent the phenomena? In this paper, I show that this question is not well posed. First, I clarify the notion of representation, and I emphasise the importance of what I call the “format” of a representation for the inferences agents can draw from it. Then, I show that the very same model can be presented under different formats, which do not enable scientists to perform the same inferences. Assuming that the main function of a representation is to allow one to draw predictions and explanations of the phenomena by reasoning with it, I conclude that imaginary models in abstracto are not used as representations: scientists always reason with formatted representations. Therefore, the problem of scientific representation does not lie in the relationship of imaginary entities with real systems. One should rather focus on the variety of the formats that are used in scientific practice.     

基于相敏检波电路的功率因数测量

电网通过电流及电压互感器后,利用相敏检波及相位补偿电路,实现功率因数实时、准确的测量.为电力管理系统提高电网功率因数提供借鉴.