我国中、新生代盆地铀矿的成矿条件及地质特征

前言我国中、新生代陆相沉积盆地,据二百万分之一地质图,可圈出大于5平方公里的1270个,占全国面积25％。若按面积大小划分,其比重是:巨型、大型盆地(1万平方公里以上)24个,占盆地总面积67.3％;中、小型盆地(1万—1千平方公里,或更小)约1246个,     

我国中、新生代盆地铀矿的成矿条件及成因模式探讨

本文根据成矿物质来源,矿床与地层构造、沉积建造、火山活动、盆地发展史等关系,把我国中、新生代盆地铀矿按矿床成因划分为三种类型:即成岩矿床,沉积改造矿床,后成(热水)矿床。各类矿床的基本地质特征详见表1。本文结合相应实例着重讨论前二种成因类型的成矿条件及成因模式。     

Persistent organic pollutants (POPs) in a small, herbivorous, arctic marine zooplankton (Calanus hyperboreus): trends from April to July and the influence of lipids and trophic transfer

Samples of Calanus hyperboreus, a herbivorous copepod, were collected (n = 20) between April and July 1998, and water samples (n = 6) were collected in May 1998, in the Northwater Polynya (NOW) to examine persistent organic pollutants (POPs) in a high Arctic marine zooplankton. Lipid content (dry weight) doubled, water content (r2 = 0.88) and delta15N (r2 = 0.54) significantly decreased, and delta13C significantly increased (r2 = 0.30) in the C. hyperboreus over the collection period allowing an examination of the role of these variables in POP dynamics in this small pelagic zooplankton. The rank and concentrations of POP groups in C. hyperboreus over the entire sampling was sum of PCB (30.1 +/- 4.03 ng/g, dry weight) > sum of HCH (11.8 +/- 3.23) > sum of DDT (4.74 +/- 0.74), sum of CHLOR (4.44 +/- 1.0) > sum of CIBz (2.42 +/- 0.18), although these rankings varied considerably over the summer. The alpha- and gamma-HCH and lower chlorinated PCB congeners were the most common POPs in C. hyperboreus. The relationship between bioconcentration factor (BCF) and octanol-water partition coefficient (Kow) observed for the C. hyperboreus was linear and near 1:1 (slope = 0.72) for POPs with a log Kow between 3 and 6 but curvilinear when hydrophobic POPs (log Kow > 6) were included. Concentrations of sum of HCH. Sum of CHLOR and sum of CIBz increased over the sampling period, but no change in sum of PCB or sum of DDT was observed. After removing the effects of time, the variables lipid content, water content, delta15N and delta13C did not describe POP concentrations in C. hyperboreus. These results suggest that hydrophobic POP (log Kow = 3.86.0) concentrations in zooplankton are likely to reflect water concentrations and that POPs do not biomagnify in C. hyperboreus or likely in other small, herbivorous zooplankton.     

PCB concentrations and metabolism patterns in common terns (Sterna hirundo) from different breeding colonies in The Netherlands

PCB levels in blood of common terns (Sterna hirundo) from Terneuzen, a breeding colony in The Netherlands with relatively low breeding success, were significantly higher than in birds from two Dutch reference colonies, one nearby (Oesterdam) and one further away (the Isle of Griend). However, a detailed analysis of the patterns of PCB congeners in birds from the different colonies indicated that birds from Terneuzen and to a lesser extent birds from the Oesterdam showed Ah-receptor mediated activity of P450 iso-enzymes. It is concluded that the induction of this enzyme activity in Terneuzen may be related to PCBs as well as other non-identified compounds. In contrast to this, it is likely that at the Oesterdam non-identified compounds are mainly responsible for the enzyme activity, resulting in a shift of PCB congener patterns.     

国省道车载GPS交通道路数据的导入

不同的GIS软件平台采用各自的数据格式，对采用多平台的数据生产、数据库建库造成了数据交换的障碍。利用ARC／INFO的二次开发功能，解决了国家基础测绘生产中GEOSTAR数据转入ARC／INFO平台的问题。     

磁通门仪记录室改造建设中有关问题的探讨

IAGA(国际地磁学和高空大气学协会 )在《地磁测量与地磁台站工作指南》中指出 ,“对放置新型磁变仪的场所有 3点主要要求 :放探头用的稳定的墩子 ,稳定的温度和无磁性的建筑材料” (周锦屏等 ,1 999)。数字地磁记录仪器的应用在许多国家已有多年历史 ,IAGA的总结对我国地磁台站磁通门记录室的建设或改造具有重要的指导意义。成都地磁台相对记录室曾采用珍珠岩颗粒夹层、加厚薄弱墙等保温措施及氯化钙防潮措施对于地下水位浅、空气湿度大的地面建筑的地磁房收到了良好的保温防潮效果。由于珍珠岩颗粒年久要缩塌 ,对保温的长期效果有一定…     

顶管施工中地面沉降的预测

该文根据某地下管线顶管施工过程中，对地面厂房建筑的沉降资料的分析，就地下顶管施工产生的主要环境效应一地面沉降提出进行预测的经验性方法，以对今后的同类工程实践提供参考。     

月预报,中期预报中的过程预报

本文根据１９８０￣１９８９年南宁地区降水资料和南宁站日平均海平面气压资料，用周期分析方法，分析桂西南地区的大气低频振荡，得出气压场和日降水量峰值的一些低频振荡的规律，并提出月、旬预报中的天气过程预报方法。     

搞好专业气象信息服务的对策

从实行专业气象信息有偿服务的必要性和实行专业气象信息有偿服务的理论依据入手，提出搞好专业气象信息服务的若干对策。     

南加州洛杉矾盆地北部S波分裂的观测结果

发生在洛杉矶盆地下面，深度为５－１８ｋｍ结晶基岩处的地震，在三分向地震图上，观测到了２０－１２０ｍｓ的Ｓ波的分裂。发生在５ｋｍ厚沉积层底部上术基岩中的浅震Ｓ波分裂现象不明显，而较深的地震Ｓ波分裂现象刚随深度逐渐明显，快Ｓ波的偏振方向为南北方向，与地震和接收点之间射线的方位角无关。