Analytical and experimental investigation on transverse vibrations of solid, circular and annular plates carrying a concentrated mass at an arbitrary position with marine applications

This investigation arose from the practical necessity of placing a centrifugal pump rigidly attached to a thin, circular cover plate of a water tank in a medium size ocean vessel. Due to lack of space, it was necessary to locate the system off—center of the circular configuration. It was considered necessary to calculate the fundamental frequency of the coupled system.The first part of the present study is concerned with the determination of the fundamental frequency of vibration of a circular plate carrying a concentrated mass at an arbitrary position, using a variational approach.Numerical results are obtained for the stated problem for several combinations of the intervening geometric and mechanical parameters.An experimental investigation is also performed in the case of clamped plates.Based on the results for solid circular plates, the fundamental frequency of annular plates with a free inner edge and a concentrated mass is also obtained.Circular plates are fundamental structural elements in ocean engineering applications: from off-shore platforms to underwater acoustic transducers. In a great variety of circumstances, they must carry operational systems in an eccentric fashion. Since the dynamic performance is always of interest, one must know at least some of the basic dynamic parameters.     

河南省安阳市主要环境地质问题及其防治对策

安阳是国家级的历史文化名城,以钢铁、电子、轻纺为主,商贸旅游业繁荣的区域中心城市.由于城市社会经济的持续增长,城市化进程不断加快,资源能源的开发利用与消耗导致环境地质问题越来越显著,同时制约了经济的发展.根据近年来的环境地质监测资料和其它有关地质成果,指出安阳市目前存在的主要环境地质问题有地下水资源衰减与短缺、地下水污染、地质灾害、不良岩土体、垃圾排放等.安阳市今后的地质工作应以改善和保护地质环境为主要方向.根据地质条件不同将安阳市主要环境地质问题的防治划分为两个区,并提出了环境地质问题的防治措施.     

河南省五大温泉成因研究及综合开发利用规划

河南省五大温泉位于鲁山县西部,自上而下为上汤、中汤、温汤、下汤和碱场温泉.受地方经济发展水平低的影响,加之对地热资源的重视不够,多年来,五大温泉的开发利用程度较低,应用领域单调,造成了地热资源的极大浪费,同时也对地质环境带来负面影响.本文在阐明五大温泉成因与出露条件的同时,结合地热资源量和地热流体的温度、化学成分,本着"科学布井,探采结合;梯级开发,综合利用;保护资源,持续发展"的原则,提出了五大温泉地热资源综合开发利用规划.     

一种批量修改GIS基础图形数据的方法

结合对地理信息系统的基础图形数据入库前的标准化工作，介绍了基础图形数据存在的问题，分析了产生的原因，最后提供一种适合对基础图形数据进行大批量修改编辑的方法，并结合实例进行了详细的阐述。     

Understanding hydrological processes with scarce data in a mountain environment

Performance of process‐based hydrological models is usually assessed through comparison between simulated and measured streamflow. Although necessary, this analysis is not sufficient to estimate the quality and realism of the modelling since streamflow integrates all processes of the water cycle, including intermediate production or redistribution processes such as snowmelt or groundwater flow. Assessing the performance of hydrological models in simulating accurately intermediate processes is often difficult and requires heavy experimental investments. In this study, conceptual hydrological modelling (using SWAT) of a semi‐arid mountainous watershed in the High Atlas in Morocco is attempted. Our objective is to analyse whether good intermediate processes simulation is reached when global‐satisfying streamflow simulation is possible. First, parameters presenting intercorrelation issues are identified: from the soil, the groundwater and, to a lesser extent, from the snow. Second, methodologies are developed to retrieve information from accessible intermediate hydrological processes. A geochemical method is used to quantify the contribution of a superficial and a deep reservoir to streamflow. It is shown that, for this specific process, the model formalism is not adapted to our study area and thus leads to poor simulation results. A remote‐sensing methodology is proposed to retrieve the snow surfaces. Comparison with the simulation shows that this process can be satisfyingly simulated by the model. The multidisciplinary approach adopted in this study, although supported by the hydrological community, is still uncommon. Copyright © 2007 John Wiley & Sons, Ltd.     

平邑盆地下第三系官中段核形石成因分析

平邑盆地下第三系官中段核形石较为发育,类型多样。通过对其内部结构的研究发现核形石单元纹层有六种类型,作为核心的藻类仅在顶端发生碎屑粘结效应,而其底部则发育厚度小,规则的暗色纹层。纹层组合类型多样,主要受藻类发育程度,水动力强度和藻类种属的控制,是不同水动力环境下的产物。根据颗粒大小、纹层组合类型纹层层数、填隙物将核形石分为浅水高能成因核形石和较深水低能成因核形石。核形石成因分析和分类对沉积环境的判     

国家1∶50000基础地理信息数据库更新工程及实施

国家1∶50 000基础地理信息数据库更新工程是我国"十一五"初启动的重点测绘工程,历经5年多实现了对1∶50 000数据库的全面更新。本文重点介绍了更新工程的背景、主要内容、技术方法、组织实施及其所取得的主要成果。     

利用Rayleigh波相速度和群速度联合反演青藏高原东北缘S波速度结构

利用青藏高原东北缘地区固定和流动地震台网2007年8月到2012年1月期间记录的远震波形,运用小波变换频时分析方法分别测定了1216和653条周期从15到140 s的台站间基阶Rayleigh相速度和群速度频散曲线.通过对上述频散进行反演,重构了青藏高原东北缘分辨率高达0.5°×0.5°的2-D相速度和群速度分布图.然后通过对所提取到的每个格网点Rayleigh波相速度和群速度频散进行联合反演,得到了研究区下方一维S波速度结构.最后通过线性插值,得到了青藏高原东北缘下方地壳上地幔三维S波结构.结果表明,印度板块向北俯冲已经达到班公-怒江缝合带附近;在柴达木盆地北部祁连山下面我们发现了亚洲板块,且其没有表现出明显的向南俯冲的迹象;在两大板块中间,我们观测到延伸到250 km深度的低速异常,该低速异常可能是地幔物质底辟上涌现象造成的.     

沉积学发展及油气勘探领域热点问题概述

沉积学发展经历了萌芽与初步形成、沉积岩石学到沉积学、沉积学全面发展3个阶段.研究范畴从微观到宏观,从沉积岩的岩类学特征深入至成因探讨,从岩石观察到对沉积相的解释.层序地层学、地震沉积学是沉积学定性到定量化研究的开端,地球化学、数值模拟和实验技术是实现定量化的有效途径.总结了当前油气勘探领域中沉积学的热点问题,如地震沉积学的理论研究和实际应用,深水沉积的识别,白云岩的成因,浅水三角洲在油气勘探开发中的发展前景,旋回地层学及全球变化沉积学的发展与挑战等,为新的理论方法和技术手段的进一步完善提供基础信息.     

知识经济时代对财会人员的素质要求

当今时代正处在由工业经济向知识经济过渡的新时期。我国改革开放和社会主义现代化建设事业蓬勃发展 ,社会主义市场经济体制逐步完善 ,加入WTO已成定局。为适应新形势的要求 ,财会人员面临新的挑战 ,肩负艰巨的任务 ,要求具备更高的素质