Two typical phenomena from the numerical simulation of fire and smoke transport in a gymnasium fire

Building a large centralized atrium in a building has become favourable both to designers and owners. The space of an atrium in a hall, theatre or gymnasium, can occupy an area as large as thousands of square meters and a height as high as 10―30 meters[1…     

Some evidence of drying trend over northern China from 1951 to 2004

The surface wetness index, Palmer drought sererity index and the retrieval of soil moisture over China were calculated using monthly precipitation and monthly mean surface air temperature. Based on the contrast analysis of the variation of the above three indices and precipitation, the dry/wet spatio-temporal pattern of northern China in the last 54 years was revealed, and the evidence of drying trend over northern China was analyzed, especially. The results show the following four facts: (1) The drying trend is the main characteristic of the eastern part of Northwest China and the central part of North China since the 1980s and it was enhanced in the last 15 years mainly due to the precipitation decrease and the temperature increase; (2) During the last 54 years, there was only one dry/wet shift at the interdecadal scale occurring in the eastern part of Northwest China and the central part of North China in the late 1970s, which was related to 1977/1978 global abrupt change, whereas there were three shifts in Northeast China, one was in the mid 1990s and the other two were in 1965 and 1983, respectively; (3) Unlike the variation trend of other subregions of northern China, the western part of Northwest China is currently located in a relatively wetting period, which is weak-ened due to the temperature increase; (4) The extreme drought frequency is obviously increasing in the eastern part of Northwest China, the central part of North China and Northeast China since the 1980s, which is closely related to the precipitation decrease and temperature increase in these subregions.     

运用EWB测试线性系统特征参数

运用广泛使用的EWB(Electronics Workbench)电子实验台,对一、二阶线性系统特征参数进行测试实验。测试实验结果准确、可靠,并探讨出一种理论教学与实验教学有机融合的可行方法。     

电脑刺绣机新型挑线机构运动分析

以电脑刺绣机新型挑线机构为研究对象，推导了机构多位移矩阵迭代求解、机构速度和加速度的理论方程，详细分析了新型挑线机构的位移、速度、加速度特性曲线．结论显示加速度变化大是导致电脑刺绣机断线的原因之一．其推导方法与优化理论相结合可用于电脑刺绣机挑线机构参数设计，以改善加速度特性曲线，降低断线率．     

隧道监控系统中交通控制方案的自动触发

通过一个隧道监控系统的研发实例，对隧道监控系统给予介绍．当隧道出现紧急事件(报警事件)时，该隧道监控系统能对各种事件做出反应，不丢失任何重要数据和报警信息，并自动触发交通控制方案，让操作员能够第一时间发现和干预，尽可能预防交通事故的发生，并为事故的处理提供及时强有力的援助，为迅速恢复道路畅通提供保障．该系统运行稳定可靠，操作简单，达到了预期的效果．     

地面坦克目标红外热成像物理模型研究

根据红外成像的基本流程，研究并建立了地面坦克的红外物理模型。针对复杂场景分别对目标和背景部分建模、求取温度场分布，同时考虑目标和背景之间的相互作用得到完整的场景红外理论模型；考虑红外辐射的大气吸收，建立了大气衰减模型；模拟红外传感器的工作特性建立成像综合响应模型。最后给出了地面坦克目标热成像系统的仿真流程，利用该系统可以在试验环境下进行目标的红外仿真，为红外系统以及武器的研制提供经济快捷的手段。     

能适应组织、人员和业务流程变化的工作流模型

在基于工作流的应用软件中，由于软件的模型灵活性不够，无法适应需求的变化，经常导致软件失效．在分析了引起工作流软件修改的主要原因之后。构造了一个角色模型，作为连接组织模型与工作流模型的桥梁．基于国际工作流联盟的工作流模型，经过修改和细化，运用模式技术、组件技术等，形成一个更容易操作和实现的工作流模型，以适应软件使用过程中出现的组织、人员和业务流程的变化，取得了较好的效果，提高了工作流软件的适应性．     

给水管道的常见事故及其预防

介绍了给水管道在施工和运行中可能出现的各种事故，分析了造成事故的原因。总结了消除给水管道事故的方法和应采取的预防措施。     

我国土地利用研究现状分析

本文分析了目前我国在土地利用领域的研究现状 .认为 :当前我国在土地利用 /覆被变化研究是土地利用研究领域的重点 ,不仅在研究内容上注重土地利用变化的动态过程、强调其驱动机制的分析及其生态环境效应的反映 ,而且在研究方法上不断探索 ;同时 ,土地利用结构的合理化及土地的可持续利用为核心内容的土地利用优化配置 ,也成为部分学者土地利用变化研究的重要内容 .     

BIOCHEMICAL PULPING OF REED PRETREATED BY WHITE ROT FUNGI

INTRODUCTIONThe origin of biological pulping is natural degradation of lignin by microorganism, such as white rot fungi. Many researches have been carried out, on the biological degradation of the lignin in raw materials, mostly on woods. Those researches were mainly focused on microorganism pretreatment as a prior proceeding of the mechanical pulping, for the rare possibility of pulping directly with the pretreatment by a microorganism. A series of reports showed that microorganism pretr…