Strong stability of the mono-tubular heat exchanger equation with output feedback

We investigate asymptotic behavior of the C₀-semigroup T(t) associated with the mono-tubular heat exchanger equation with output feedback by a perturbation method. It is shown that T(t) is bounded if a constraint is satisfied by the parameters and the spatial distribution function. Further, applying the Arendt-Batty-Lyubich-Vu theorem, a criterion is established to judge strong stability of T(t).     

生物过程在线监控远程多媒体报警系统的研制

对生物过程在线监控远程多媒体报警系统的功能、组件构成及通信方式进行了全面介绍。     

Matlab和C++接口中函数注册的实现

函数注册在Matlab和C 接口中起着重要的作用。在介绍函数注册作用的基础上 ,详细分析了函数注册的过程及应当注意的问题 ,并给出了一种实现函数注册的最简单的方法。用实例展示了函数注册的具体实现过程。     

一种采用80C196KC的伺服控制系统的设计

介绍了一块用于三轴稳定跟踪装置中位置伺服控制卡的软、硬件设计。硬件电路实现了数据采集、D/A输出、上下位机通讯和输入输出信号接口等功能。单片机程序采用C96语言编制。软硬结合进行系统联调 ,效果很好     

自动生成CGI C++/C源程序

主要讨论如何利用软件自动生成ＣＧＩ的Ｃ／Ｃ＋＋源程序。     

Espaces métriques rationnellement présentés et complexité, le cas de l'espace des fonctions réelles uniformément continues sur un intervalle compact

We define the notion of rational presentation of a complete metric space, in order to study metric spaces from the algorithmic complexity point of view. In this setting, we study some representations of the space C[0,1] of uniformly continuous real functions over [0,1] with the usual norm: ||f||_∞ = Sup{|f(x)|; 0x1}. This allows us to have a comparison of global kind between complexity notions attached to these presentations. In particular, we get a generalization of Hoover's results concerning the Weierstrass approximation theorem in polynomial time. We get also a generalization of previous results on analytic functions which are computable in polynomial time.     

基于模糊控制的异种电动机同步控制

本针对光纤成缆机生产线上的多只异种电动机的线速度同步控制提出了模糊控制与PI控制相结合（FUZZY－PI）的方法,实践证明此方法具有动态响应快,超调量小,精度高,能很好的达到生产要求。     

PCI总线在双谱段探测系统中的应用*

PCI是DSP应用系统与通用计算机高速通信的理想接口。介绍了一种双谱段探测系统的PCI接口方案,该方案采用TI公司的TMS320F2812 DSP作为控制单元主控芯片,采用Cypress公司PCIDP系列的CY7C09449PV作为PCI接口芯片,具有接口简单方便易于实现的优点。详细讨论了CY7C09449PV与TMS320F2812的硬件连接、参数配置与时序分析。     

混合碳四的来料加工

分析了混合碳四中3种关键组分超标对丁二烯生产的不利影响，提出了外加工混合碳四过程中具体的应对措施和解决方案。     

The confused world of sulfate attack on concrete

External sulfate attack is not completely understood. Part I identifies the issues involved, pointing out disagreements, and distinguishes between the mere occurrence of chemical reactions of sulfates with hydrated cement paste and the damage or deterioration of concrete; only the latter are taken to represent sulfate attack. Furthermore, sulfate attack is defined as deleterious action involving sulfate ions; if the reaction is physical, then, it is physical sulfate attack that takes place. The discussion of the two forms of sulfate attack leads to a recommendation for distinct nomenclature. Sulfate attack on concrete structures in service is not widespread, and the amount of laboratory-based research seems to be disproportionately large. The mechanisms of attack by different sulfates—sodium, calcium, and magnesium—are discussed, including the issue of topochemical and through-solution reactions. The specific aspects of the action of magnesium sulfate are discussed, and the differences between laboratory conditions and field exposure are pointed out.Part II discusses the progress of sulfate attack and its manifestations. This is followed by a discussion of making sulfate-resisting concrete. One of the measures is to use Type V cement, and this topic is extensively discussed. Likewise, the influence of w/c on sulfate resistance is considered. The two parameters are not independent of one another. Moreover, the cation in the sulfate salt has a strong bearing on the efficiency of the Type V cement. Recent interpretations of the Bureau of Reclamation tests, both long term and accelerated, are evaluated, and it appears that they need reworking.Part III reviews the standards and guides for the classification of the severity of exposure of structures to sulfates and points out the lack of calibration of the various classes of exposure. A particular problem is the classification of soils because much depends on the extraction ratio of sulfate in the soil: there is a need for a standardized approach. Taking soil samples is discussed, with particular reference to interpreting highly variable contents of sulfates. The consequences of disturbed drainage of the soil adjacent to foundations and of excessive irrigation, coupled with the use of fertilizer, are described. Whether concrete has undergone sulfate attack can be established by determining the change in the compressive strength since the time of placing the concrete. The rejection of this method and the reliance on determining the tensile strength of concrete because of “layered damage” are erroneous. Scanning electron microscopy (SEM) should not be the primary, and certainly not the first, method of determining whether sulfate attack has occurred. Mathematical modeling will be of help in the future but, at present, cannot provide guidance on the sulfate resistance of concrete in structures.Part IV presents conclusions and an overview of the situation, with consideration of future improvements. Appendix A contains the classification of exposure to sulfate given by various codes and guides.