常见稀有气体采样容器研究进展及意义

稀有气体是地学研究的重要手段之一,在研究成矿流体来源、壳幔相互作用过程中具有重要的研究意义,其组成及同位素比值是研究天体和地质体来源、成岩机理及各种地质和物理化学过程的关键,可作为地球化学示踪剂。如何有效地在大气圈、水圈和岩石圈进行稀有气体同位素样品的提取,是气体同位素研究急需解决的基础科学问题,所以气体采样容器和取样技术显得尤为重要。本文在文献调研的基础上,对常见的采样容器的优缺点进行对比,并总结了不同采样容器对稀有气体取样的优劣性。常见的气体采集容器包括不锈钢瓶、铜管、玻璃瓶、气体采样袋、注射器等,而稀有气体的采集容器常为不锈钢瓶和铜管等;通过对比表明不锈钢瓶具有耐高温、耐高压、抗强腐蚀、不易燃、不易爆等特点和优越性,在气体样品采集和运输过程中稳定性最好,实验效果也最好;铜管采样效果和密封性好,但操作较为复杂;玻璃采样容器效果次之;石英玻璃瓶虽然操作简便,但是运输保存不便;气体采样袋和注射器的采集和运输储存效果较差。因此建议稀有气体样品采集使用不锈钢瓶和铜管以及钠钙材质的玻璃瓶,不建议将石英材质玻璃容器以及注射器和气袋作为稀有气体的采样工具。该工作可为气体地球化学的研究提供新的参考。     

Stability of elevated liquid-filled conical tanks under seismic loading,Part I—theory

Conical steel shells are widely used as water containments for elevated tanks. However, the current codes for design of water structures do not specify any procedure for handling the seismic design of such structures. In this paper, a numerical model is developed for studying the stability of liquid-filled conical tanks subjected to seismic loading. The model involves a previously formulated consistent shell element with geometric and material non-linearities included. A boundary element formulation is derived to obtain the hydrodynamic pressure resulting from both the horizontal and the vertical components of seismic motion acting on a conical tank which is prevented from rocking. The boundary element formulation leads to a fluid added-mass matrix which is incorporated with the shell element formulation to perform non-linear dynamic stability analysis of such tanks subjected to both horizontal and vertical components of ground motion. Although, the formulation was developed for conical vessels, it is general and can be easily modified to study the stability of any liquid-filled shell of revolution subjected to seismic loading. The accuracy of fluid added-mass formulation was verified by performing the free vibration analysis of liquid-filled cylindrical tanks and comparing the results to those available in the literature. © 1997 John Wiley & Sons, Ltd.     

鲐鱼灯光围网渔船水上集鱼灯水中照度分布及优化配置的理论计算

采用叠加法照度计算模式,根据一组鲐鱼灯光围网渔船中3艘不同渔船的水上集鱼灯布置参数,使用自行开发的水上集鱼灯水下光场计算系统,对各船的水中照度分布进行了计算,获得船舷右侧中部水深方向200 m范围内不同深度的照度,并使用Surfer 8.0软件绘制等值曲线图,结果表明:主灯船在总功率为180 kW的情况下,10 lx的等照度曲线水平方向最远在56 m左右,水深方向不超过20 m;离船水平距离40 m、垂直距离40 m处的照度约为0.01 lx。副灯船在总功率为120 kW的情况下,10 lx的等照度曲线水平方向最远在46 m左右,水深方向不超过18 m;离船水平距离33 m、垂直距离38 m处的照度约为0.01 lx。网船在总功率为40 kW的情况下,10 lx的等照度曲线水平方向最远在45 m左右,水深方向不超过15 m;离船水平距离30 m、垂直距离35 m处的照度为0.01 lx左右。从集鱼灯的配置情况来看,主灯船、副灯船与网船目前的配置均较好,但主灯船在灯距增大到0.26 m、灯高增大到5 m时可增加1.6%的有效水体体积,副灯船在灯距减少到0.28 m、灯高增大到5 m时可增加2.1%的有效水体体积,网船在灯距增大到0.64 m、灯高增大到9 m时可增加1.7%的有效水体体积。计算结果还表明,大幅度的增加光诱渔船的集鱼灯功率并不能很有效的提高该船的光诱范围。     

偏压、错台小间距隧道施工位移场动态模拟分析

采用三维非线性有限元法,对偏压、错台的浅埋小间距隧道在不同开挖顺序下的动态施工过程进行了模拟。通过对位移场的分析,研究了其施工力学特性。由于两隧洞之间的相互影响,并行小间距隧道对围岩的扰动程度大于两独立隧道作用的叠加;相互影响对中间岩柱的作用最为明显,对洞周、地表影响相对较弱。两洞开挖顺序不同,最终位移场的分布规律相同,但量值上存在一定差异。研究给出了在偏压、错台情况下的两洞开挖的合理顺序。     

泛滥平原沉积物的超低密度采样代表性研究(一)

运用１个样／１ｋｍ２、１个组合样／４ｋｍ２，１个样／（１００～１０００）ｋｍ２、１个样／（１０００～１００００）ｋｍ２的采样密度系统研究了泛滥平原沉积物的超低密度采样代表性。通过对Ｓｂ、Ａｓ、Ａｇ、Ｐｂ、Ｓｎ、Ｎａ２Ｏ元素的地球化学分布模式，Ｗ的地球化学特征在不同采样密度间的信息传递，证明了用１个样／（１０００～１００００）ｋｍ２的采样密度，采集的泛滥平原沉积物具有代表性     

我国战略石油储备船概念设计研究

阐述了建立我国战略石油储备的必要性，对国外石油储备状况及储备方式做了简要介绍。从我国国情出发，提出了80万m^3浮式钢结构储油船方案设计，建立了储油船整船有限元模型，利用全船三维有限元结构分析技术进行了油舱的分舱设计，供超大型储油船设计时参考。     

Wave resistance for high-speed catamarans

The object of this study was to investigate the wave resistance component for high-speed catamarans. Two methods were applied: the slender-body theory proposed by Michell [Philos. Mag. 45(5) (1898) 106] and a 3D method used by Shipflow^™ (FLOWTECH, Shipflow^™ 2.4, User Manual, 1988) software.Results were obtained for different types of twin hulls and attention was given to the effects of catamaran hull spacing.The study also included the effects of shallow water on the wave resistance component.Special attention was given to the height of waves generated by the craft to ascertain effects on river banks.     

Royal Navy cuts—former minister comments

These articles concern two countries with broadly similar diplomatic and military alignments but with defence policies which appear to be evolving in opposite directions. In the first article, Keith Speed MP, Parliamentary Under-secretary of State for the Royal Navy until May 1981, offers a critique of UK naval policy as outlined in the Defence White Paper of June 1981. In the second article, Kaiji Yamaguchi, a professor of international law and member of the Japanese Navy, analyses Japan's defence imperatives in the light of Soviet activity in North-east Asia and US pressure on the Japanese government to increase its defence budget. Both articles highlight the dilemma posed by Soviet expansionism requiring a positive response from the West and a world recession which demands reductions in public spending.     

AIS船舶污染风险定量评估模型

针对目前海上船舶污染风险评估模型的不足,本文提出一种基于船舶自动识别系统(AIS)的海上船舶污染风险定量评估数学模型。该模型的特点是对特定海域船舶污染历史事故进行统计分析,通过AIS中的信息对船舶事故频率进行建模及数值计算;并且模型考虑到事故海域资源类型,船舶种类、大小、风险程度以及污染事故等级等因素,使污染风险评估更科学化和定量化。