TopSTO: a 115-line code for topology optimization of structures under stationary stochastic dynamic loading

The use of topology optimization in structural design under dynamic excitation is becoming more prevalent in the literature. While many such applications utilize frequency or time domain formulations, relatively few consider stochastic dynamic excitations. This paper presents an efficient and compact code called Top STO for structural topology optimization considering stationary stochastic dynamic loading using a method derived from random vibration theory. The theory, described in conjunction w...     

欧亚冰盖的消融

巴巴多斯和新几内亚的海平面变化表明：在过去的15000a中曾有过两次大规模的冰川融水流．同其它环境变化(如北大西洋深水环流)相比，这两次融水流形成的时间显然有助于我们进一步了解从未次冰期到问冰期的气候变迁及新仙女木事件．     

一种新型的米辛尼亚期（Messinian）的复合微生物岩丘建造

在Salemi（西西里西部）附近的米辛尼亚期沉积岩中，我们对一种新型的以米为单位的复合补丁礁进行了描述．其建造由两个截然不同的部分组成：（1）陡倾穹隆状微生物岩丘夹凝块叠层石和结壳状生物；（2）覆盖在微生物岩五上的珊瑚一微生物建造，其中珊瑚群体为微生物岩石所覆盖（这些微生物岩石与各种各样的结壳生物有关）．微生物岩丘的增生作用是葡萄状集合体的发育、畚箕藻骨骼、结完状有孔虫、苔鲜动物、龙介虫和已胶结双壳类的堆积结果．正如地中海中其它类似的米辛尼亚期生物建造，不同部分复合微生物岩丘建造的增生过程似乎是均一的…     

美国中尺度天气预报的现状和展望

本文综合评述了美国主观中尺度天气预报的前景,并指出改进中尺度天气预报的主要可能性:(1)资料来源迅速扩大;(2)贮存、分析和显示资料的新型计算硬件;(3)下个5年内,计划把主要力量放在改进中尺度预报上,如风暴尺度业务和研究气象学(STORM)计划、九十年代先进的天气交互处理系统(AWIPS-90)等规划。目前人所共知的尚未解决的问题是:(1)如何集中不同来源的资料以及如何解决过剩的信息;(2)如何提高我们对中尺度和其它尺度大气运动相互作用的认识;(3)如何培养出新一代预报员。对最后一个问题,UNIDATA计划正在帮助一些大学加强中尺度气象学的教学。     

Tidal flushing and wind driven circulation of Ahe atoll lagoon (Tuamotu Archipelago, French Polynesia) from in situ observations and numerical modelling

Hydrodynamic functioning and water circulation of the semi-closed deep lagoon of Ahe atoll (Tuamotu Archipelago, French Polynesia) were investigated using 1year of field data and a 3D hydrodynamical model. Tidal amplitude averaged less than 30cm, but tide generated very strong currents (2ms(-1)) in the pass, creating a jet-like circulation that partitioned the lagoon into three residual circulation cells. The pass entirely flushed excess water brought by waves-induced radiation stress. Circulation patterns were computed for climatological meteorological conditions and summarized with stream function and flushing time. Lagoon hydrodynamics and general overturning circulation was driven by wind. Renewal time was 250days, whereas the e-flushing time yielded a lagoon-wide 80-days average. Tide-driven flush through the pass and wind-driven overturning circulation designate Ahe as a wind-driven, tidally and weakly wave-flushed deep lagoon. The 3D model allows studying pearl oyster larvae dispersal in both realistic and climatological conditions for aquaculture applications.     

青藏高原乌丽冻土区二氧化碳成因探讨

为了查明青藏高原乌丽冻土区天然气的组分与成因,对采集自乌丽水合物试验孔ZK1井及其周边钻孔的岩心顶空气、岩心解析气以及湖水气进行了组分和碳同位素测试分析,同时对ZK1井及其周边钻孔岩心中的碳酸盐岩碳同位素进行了测试分析。测试结果显示:该区天然气主要成分为二氧化碳,其含量在98%以上,烃类气体(主要为甲烷)含量很少;二氧化碳碳同位素主频在-4‰～-6‰(VPDB)之间,少量富烃样品的甲烷碳同位素主频介于-3238‰～-2782‰（VPDB）之间,碳酸盐岩的碳同位素平均值为-387‰（VPDB）。综合分析认为,研究区二氧化碳主要为幔源成因,可能与该区强烈的构造运动和岩浆活动有关。     

露头三角洲的研究现状及研究方法

露头三角洲的研究进基于进一步提高油气田的采收率和寻找出更为陷蔽的油气藏而发展起来的。目前世界上一些大石油公司或跨国集团已投入或正投入巨资进行露三角洲的研究。     

三角洲的分类

本文在对国内外现代和古代三角洲调研的基础上,结合我国中新生代含油气盆地中三角洲的发育特点将三角洲划分为二类７个亚类。     

RESUSPENSION OF FINE SEDIMENT IN RESERVOIRS - A CASE STUDY OF THE LOWER INN RIVER

1 THE LOWhR unR INNThe Inn river has its source in the alPine region of the GraubUnden canton of Switzerand. ThecatChment area of about 260(X} kIn2 includes mountains of the central Alpes up to 40(X) m. The river runs5l7 km thrOugh the countries of SwitZerand, Austria and Germany on itS way into the Danube mver. Thedischarge of the river at its mouth in the city of Passau is mainly infiuenced by the snow melt in themountainous catchment area and vches between apProx. 200 m3ls durin…     

天然气水合物的开发试验有如星星之火——第6届国际天然气水合物会议

1会议概况 2008年7月610日,第6届国际天然气水合物大会在加拿大温哥华举行。参会人员共计526人,其中亚洲参会人员占38％,欧洲参会人员占25％,美洲参会人员占37％。本次大会共提交论文417篇,主题发言2篇,分别由加拿大地调局DallimoreS和美国地调局ColleztT所作,题目分别是“2007年Mallik天然气水合物开发情况介绍”和“印度天然气水合物国家计划成果介绍”。