西安市地震应急指挥技术系统设计与实现

本文从系统总体架构设计、系统功能设计与应用成果、系统特色4个方面简要介绍了西安市地震应急指挥技术系统设计与实现情况.本系统是首个应用于省会城市地震应急工作,并基于国产Server GIS软件平台研制开发出的地震应急指挥技术系统,可为大城市地震应急指挥技术系统的建设与发展提供可借鉴的经验.     

2009年秋季河南一次连阴雨天气成因分析

采用合成分析和动力诊断分析及统计方法,利用NCEP资料和常规气象观测资料对造成2009年9月6-20日河南省北中部地区15 d连阴雨天气成因进行分析.结果表明:200 hPa高空急流的出现并且维持,南亚高压的偏东偏北,副热带高压的偏西略偏北,以及边界层的东北风(或偏东风),是造成此次长连阴雨天气的主要影响因素;200 ...     

用三通道合成彩色图像进行云的分类解释判读

为更好地利用FY-3A气象卫星上中分辨率光谱成像仪(MERSI)资料高空间分辨率及多光谱的优势,细致分析云系在宏、微观方面的多重特征,首先利用平面平行辐射传输模式(SBDART)证明了MERSI的0.65,1.6 μm和11.25 μm通道能够分别反映云光学厚度、云粒子大小、云顶高度的信息,然后采用三通道合成彩色图像的...     

Local, global and virtual buzz: The importance of face-to-face contact in economic interaction and possibilities to go beyond

Novel information and communication technologies have created new possibilities for transferring information and knowledge over distance. Although this might open up broad options for economic interaction, knowledge regarding the effects of these changes on the geographies of production and innovation is still incomplete. Under these circumstances, permanent co-location and face-to-face (F2F) interaction may be efficient in some contexts but not in others. Support by computer-mediated communication (CMC), temporary, and virtual interaction is increasingly becoming the basis for establishing trans-local production networks. By combining results from social psychology with economic geography, it is argued that there is no generally superior spatial fix for economic interaction. Different spatial configurations can be advantageous in different production and innovation contexts, even over large distances without permanent or even regular F2F contact. This paper systematically investigates the effects of new communication technologies and different organisational forms for economic interaction by emphasizing the potential of combining CMC with forms of temporary and permanent F2F interaction.     

历史极端雨涝事件研究——1823年我国东部大范围雨涝

1823年(清道光三年)我国发生大范围、多流域的严重雨涝,这是在小冰期寒冷气候背景下的重大气象灾害和极端气候事件.文章依据历史文献记载复原了1823年的气候实况并绘图显示,指出该年我国华北夏季雨期长、多大雨,北京6～8月雨日53天、降水量663mm超过现代(1971～2000年)平均值5成;长江中下游全年多雨,梅雨期长...     

城市开发区工业与生活混合污水处理设计——以四川省成都市某工业开发区为例

城市工业开发区建设时推荐我国工业规模化和产业结构升级的重要措施和手段.但随着而来的是各种各样的工业废水、生活污水汇聚,为城市污水处理厂设计和工艺选择提出了新的要求.文章以四川省成都市为例,生化处理部分采用改良A2/O工艺.结果表明,该工艺具有较好的除氮去磷效果,出水可稳定达到国家<城镇污水处理厂污染物排放标准>(GB1...     

四溴双酚A的合成工艺改进

以乙腈为溶剂,在H2O2存在下,以双酚A、溴为原料制备了四溴双酚A,讨论了加料方式、搅拌速率、n(Br2)/nBPA、反应温度、氧化剂的滴加速度等工艺条件对制取四溴双酚A产率的影响。在选定的实验条件下制取四溴双酚A的产率可达95.2%。     

NNFFC-adaptive output feedback trajectory tracking control for a surface ship at high speed

An adaptive output feedback controller based on neural network feedback-feedforward compensator (NNFFC) which drives a surface ship at high speed to track a desired trajectory is designed. The tracking problem of the surface ship at low speed has been widely investigated. However, the coupling interactions among the forces from each degree of freedom (DOF) have not been considered in general. Furthermore, the influence of the hydrodynamic damping is also simplified into a linear form or neglected. On the contrary, coupling interactions and the nonlinear characteristics of the hydrodynamic damping can never be neglected in high speed maneuvering situation. For these reasons, the influence of the nonlinear hydrodynamic damping on the tracking precision is considered in this paper. Since the hydrodynamic coefficients of the surface ship at high speed are very difficult to be accurately estimated as a prior, it will be compensated by NNFFC as an unknown part of the tracking dynamics system. The stability analysis will be given by the Lyapunov theory. It indicates that the proposed control scheme can guarantee that all the signals in the closed-loop system are uniformly ultimately bounded (UUB), and numerical simulations can illustrate the excellent tracking performance of the surface ship at high speed under the proposed control scheme.     

1819年黄河中游极端降水:史实、特征及气候背景

据清官档案与方志记载,复原了1819年(清嘉庆二十四年)黄河中、下游大范围房屋倒塌、民田冲没、人口伤亡、黄河多处决溢等雨涝灾情图景及时空分异特征,这是在明清小冰期大气候背景下的极端气候事件和重大气象灾害.研究指出,该年黄河中游夏秋季雨期长(连阴雨)、且多大到暴雨,二级流域(汾河、渭河)6-9月份降水县区雨日高达40日以...     

基于HJ-1B/IRS的重庆市热岛效应监测应用

本文利用MODIS数据反演大气透射率,利用HJ-1B/CCD进行分类,并反演地表比辐射率.在此基础上,借鉴单窗算法,利用HJ-1B/IRS数据反演得到地表温度,并利用MODIS温度产品对反演结果进行了初步验证.最后利用热场变异指数进一步分析重庆的热岛空间分布特征,并对NDVI与NDBI对热岛效应的影响进行了分析.其结论...