未定名矿物(Bi38CrO60)的矿物学研究

人工合成立方晶体Bi38CrO60在自然界首次发现于中国陕西省洛南县驾鹿金矿床中,暂称之为未定名矿物.其共生和伴生矿物有黄铁矿、自然金、碲金矿、含氧金矿物等.常呈不规则粒状集合体,偶见立方体微晶(粒径小于0.05 mm),棕黑色,金属光泽;HV=232.78 kg/mm2 ,HM=4.15;D=14.10(3)g/cm3,Dx=14.08(2)g/cm3,n=3.14(3).EPM8100探针分析Bi2O3为98.854%、CrO3为1.111%,合计99.965%,化学式为Bi38.009Cr0.995O60;CAMEBAX-SX51探针分析Bi2O3为98.862%,CrO3为1.112%,合计99.974%,化学式为Bi38.008Cr0.996O60.均可写为Bi38CrO60.X射线粉晶分析主要强度线d(I)(hkl)分别为0.321 5(100),(310);0.272 11(72),(321);0.171 45(40),(530);0.169 6(30),(600);0.165 1(30),(611);0.160 8(30),(620);0.294 11(25),(222);0.359 6(22),(220);0.217 1(20),(332);0.150 3(20),(631),等轴晶系,可能的空间群为Im3m;a=1.018 1(1)nm,c/a=1,晶胞体积v=1.055 29(1)nm3,z=1.1-Kp/Kc=0.019.Cr6 ,Bi3 ,O2-.未定名矿物和人工晶体的化学成分与X射线粉晶数据基本一致.     

湖南大坳地区云英岩蚀变体型钨锡矿床地质特征及控矿因素

大坳云英岩蚀变体型钨锡矿产于九嶷山复式花岗杂岩体中。钨锡矿体赋存在呈半隐伏产出的蚀变体中，且自下而上重叠分布，具“楼层式”结构的特点；矿体形态、有用组分的分布具有明显的分带性，产状、形态的变化与蚀变体具有一致性。研究认为花岗岩浆的侵位、区域性断裂的多次脉动作用及蚀变作用是区内钨锡矿形成的重要控制因素。     

中国南方海相含油气保存单元的层次划分与综合评价

以最近十年中国南方的海相新区油气勘探评价成果为依托 ,以油气成藏和整体封闭保存体系评价为核心 ,在渝东—湘鄂西、中下扬子和滇黔桂三大区域划分出 9个有利区块 5 1个含油气保存单元 ,并将其归纳为四个层次。综合评价认为 ,方西和石柱保存单元具有较好的整体封存体系 ,属持续性含油气保存单元 ,为首选勘探目标 ;江汉盆地南部、句容—海安区块、南鄱阳坳陷、楚雄盆地东北部具备或基本具备整体封存条件 ,属于沉积重建型含油气保存单元 ,通过精细勘探可望获得商业性油气流 ;楚雄盆地西北部、南盘江坳陷、十万大山盆地和渝东—湘鄂西地区利川复向斜由于晚期强烈构造改造而仅存在部分封存体系 ,需要攻关探索 ;思茅、渝东—湘鄂西地区的花果坪和桑植—石门地区已失去整体封闭保存条件 ,仅局部存在封存体系 ,地质条件高度复杂 ,勘探风险甚高。     

Isotopic Characteristics and Key Factors Favoring the Formation of Fuwan Super-large Silver Deposit in Guangdong Province

Rb-Sr isochron age of fluid inclusions in quartz from the Fuwan super-large silver deposit is 68 - 6 Ma, the silver deposit is characterized by high μ values (10.67 - 10.95 ), which are much higher than those of the ore-hosted Paleozoic strata and are close to those of ores hosted in the Proterozoic metamorphic basement in western Guangdong Province. Based on the Pb isotopic characteristics, coupled with much high background silver contents (200-1000ng/g) in the Proterozoic basement and relatively low silver contents in the Paleozoic strata in the region of the Sanshui Basin, it is concluded that the ore-forming material of the super-large silver deposit came mainly from the old basement. The super-large silver deposit related genetically to the intense volcanic activities during the Upper Cretaceous to Eogene. The formation of the Fuwan super-large silver deposit is controlled by the following favorable geological conditions : ( 1 ) The intersection of deep faults and contemporaneous faults at the margin of the Sanshui Basin led to the formation of an excellent structure as passageway for ore fluids; (2) The special ore-hosted rock association forms a ore gathering-trap structure that favors the precipitation of ore; (3) The silver-rich old basement, multi-stage mineralization and multi-episode volcanic activities which constitute a geothermal convection system.     

地基GPS气象学研究的主要问题及最新进展

目前大多数映射函数在低高度角时精度都比较差，发展适应低高度角的映射函数，提高低高度角观测值的利用率，研究大气的水平梯度是目前地基GPS气象学的主要研究任务，发展随时空变化的动态映射函数也是国际上的一个主要研究问题。由于PWV不能提供水汽分布的三维信息，求定GPS信号斜路径方向上的水汽SWV，以及利用SWV层析大气的垂直结构是目前国际上 GPS气象学的研究前沿。文中总结了目前国际上SWV的求定及层析水汽三维结构的主要方法，及存在的问题。把GPS探测的水汽同化到数值天气预报中，以提高数值预报的能力是GPS气象学研究的目的，作者介绍了目前水汽在数值预报模型中的同化情况。另外还回顾了利用GPS观测结果进行全球气候变化和大气折射环境研究的进展。     

藏南特提斯喜马拉雅带中段二叠纪-白垩纪的火山活动(Ⅰ):分布特点及其意义

在野外实地考察和追索的基础上，详细厘定了特提斯喜马拉雅带中段晚古生代以来火山岩的分布特点和迁移规律。结果表明，在特提斯喜马拉雅带中段晚古生代以来的地层系统中，从二叠纪→三叠纪→侏罗纪→白垩纪，共有11个层位含规模不等的火山岩，它们以透镜体、薄夹层或以块状玄武岩、玄武质安山岩等形式产出于不同地层系统中；从二叠纪→早中三叠世→晚三叠世→侏罗纪和白垩纪，具有由西向东、从南→北→南→北的迁移规律。这些火山活动的发现和厘定，对填补特提斯喜马拉雅带火山岩研究的空白，了解陆下岩石圈地幔和软流圈地幔之间的相互作用和新特提斯洋盆的形成演化都具有一定的指示意义。     

21世纪中国地质灾害防治形势与减灾战略思考

文章论述了21世纪中国地质灾害减灾面临的形势是既存在许多有利条件又存在多方面困难而面临严重挑战。提出21世纪地质灾害减灾战略：1．建立地质灾害防治安全维护体系；2．优先安排西部地区地质灾害防治工程，实施地质灾害风险管理；3．建立矿山地质灾害防治监督管理体系；4．城市地质灾害防治与土地利用相结合；5．加强我国地质环境监测与网站建设；6．针对地质灾害区域分布规律，采取分区减灾对策；7．加大地质灾害防治投入力度。     

An experimental study on seismic responses of multifunctional vibration‐absorption reinforced concrete megaframe structures

Two models are tested on a shake‐table. One of the models is a normal reinforced concrete megaframe structure and the other is a multifunctional vibration‐absorption reinforced concrete megaframe structure in which the laminated rubber bearings are placed between the major frame and the minor frames. Two earthquake motions (the El Centro wave and the Taft wave) are used during the test. This paper presents the dynamic characteristic, the seismic responses and the failure mechanism of these two models under varying peak acceleration levels for each of the earthquake motions. The test results demonstrate that the aseismic behavior of a multifunctional vibration‐absorption reinforced concrete megaframe structure is much better than that of a normal reinforced concrete megaframe structure. Copyright © 2003 John Wiley & Sons, Ltd.     

Seismic structural control using an electric servomotor active mass driver system

This study investigates an electric‐type active mass driver (AMD) system for structural vibration control. Composed primarily of an electric servomotor and a ball screw, the electrical AMD system is free from noise problems, oil leakage, and labor‐intensive maintenance that commonly are associated with hydraulic AMD systems. The desired stroke amplification of the mass and the power demand of the servomotor can be adjusted via the ball screw pitch, which in turn affects the effectiveness and efficiency of the system. Meanwhile, an instantaneous optimal direct output feedback control algorithm is adopted. Numerical simulation is performed using a five‐story steel frame as the object structure under the conditions of the 1940 El Centro earthquake. The AMD system proves to be effective and efficient within a certain range of the ball screw pitch. The reductions of the peak responses can reach as high as 70% if properly designed. Requiring only the velocity measurement of the top floor for on‐line feedback control, the proposed control algorithm is recommended for practical implementation. Copyright © 2004 John Wiley & Sons, Ltd.     

南京-镇江地区多目标地球化学调查初步成果

报道了南京—镇江地区开展的多目标地球化学调查工作以来所取得的初步成果,讨论了如何确定土壤中元素的背景值、如何检查评价地球化学异常、如何针对农业地质的需要开展深入研究等问题,并提出了开展调查工作的具体建议。