普查与勘探金属、非金属矿床与煤矿的地球物理方法

最近几十年来,地球物理勘探方法越来越受到人们的重视。这些方法是建立在研究自然和人工物理场(重力场、磁场、电场)基础上的。这些场反映具有一定物理特性(密度、磁化率、导电率)岩石的分布。当金属矿具有异乎寻常的物理特性,如矽卡岩矿岩磁化强度、多金属矿的导电率,而且根据地质和地球物理分析它们是处于均匀环境中,这时物探方法便可直接找矿。通常,除了由矿体引起的异常外,还可能出现类似的响应,如岩石中有意义的磁铁矿混合物、石墨化或黄铁矿化都可能引起类似响应。这就需要同时研究几个物理参数来促进地质解释。有些类型矿床在物理场中没有反应,这主要是因为物理特性不适合或是由于有用矿物含量少的原因。然而以往的经验清楚地证明,即使矿体在物理场中没有任何变化,当用地球物理方法也是有价值的。它可以帮助解决许多直接与勘探有关的问题,如地质填图、确定大地构造特征、研究岩石学、化学磁性的差异、变质作用和侵入岩的大小等。地球物理方法与地质及地球化学方法在普查和勘探金属矿中都是一种极其重要的工具。近年来由于科学技术的发展,仪器制造的改进和自动数据处理,促进了应用地球物理的发展。精密仪器(质子共振磁力仪、伽玛射线能谱仪、电磁仪器)的使用,使测量能在地面、空中(飞机、卫星)和水面上(船)进行。     

关于扭转扰动对简单对称建筑物地震反应影响的注记(英文)

研究表明,扭转扰动可能导致建筑物周边的构件中最大剪力和弯矩的显著增加。以前的研究已将扭转反应与结构的非对称性(即结构的抗力中心与质量中心不重合)相联系。本文研究涉及SH波和Love波的强地面运动的扭转加速度是如何引起对称结构的扭转反应的。     

风的垂直结构对于对流性降水的影响

一、前言本文探讨不用热力学参量而用标准高空探测所揭示的风的垂直结构来解释部分降水变率的可能性。 Zawadzki和Ro(1978)研究中尺度范围的降水和热力学变量的关系时揭出(下称Ⅰ),最大降水率中60％的连续暴雨变率和对流性静力能(气块)有关。在以后的研究中(1981),     

用氢氧化钠溶矿、分光光度法测定矿石中的氟

<正> 在测定难溶氟化物,如氟石、冰晶石中所含的氟时,样品难于分解是众所周知的。许多方法是采用二氧化硅、碱金属的碳酸盐和氟结合的办法来溶矿。Adolph采用二氧化硅、氟化物和钠-钾碳酸盐混合物的摩尔比为1:1:6。而Hawley认为碳酸盐有四倍摩尔比就足够了。     

地震台网的震中定位精度判据

用已出版的地震报告中的数据对震中精度进行了可靠且保守的估计。因为大量的地震研究依赖于地震定位报告,所以要估算地震定位误差。地震定位和参数估算大多数都是通过传统的线性反演方法用一维地球模型计算走时来获得。假设误差是高斯分布、零均值和不相关的,报告给出的定位结果是不精确的。遗憾的是,这种假设通常情况下是不成立的,特别对高置信度而言,不能真实估算定位误差。研究发现,地震定位精度与地震台网的几何形状紧密相关。我们利用两个确定震中位置的爆破形成近震台网(0°~2·5°)的定位判据。利用蒙特卡罗模拟台网几何,我们发现当近震台网符合以下判据时近震台网定位能精确到5km之内,具有95%的置信度:(1)250km以内有10个或更多的台站;(2)方位角小于110°;(3)次级方位角小于160°;(4)30km以内至少有一个台站。为得到近区域台网(2·5°~10°)、区域台网(2·5°~20°)和远震台网(28°~91°)的地震定位精度判据,我们使用了大量定位很好的地震和核爆炸数据。当超过局部范围时,我们发现次级方位角足以控制定位精度。当次级方位角超过120°时,定位误差将增加。当台站覆盖的次级方位角标准小于120°时,近区域台网的定位精度为20km,具有90%的置信度,区域台网和远震台网的定位精度为25km,具有90%的置信度。     

The non-native seaweed Asparagopsis armata supports a diverse crustacean assemblage

This is the first study describing the crustacean fauna associated to Asparagopsis armata, a non-native, red seaweed widely distributed along western Mediterranean coasts. First found in Australia and New Zealand, it was introduced naturally through the Strait of Gibraltar and rapidly spread out. A one-year spatio-temporal study (Feb 08-Feb 09) was carried out in the Strait of Gibraltar to characterize the spatio-temporal patterns of the associated crustacean fauna. Maximum biomass of A. armata was measured during April-June, whereas the maximum crustacean abundances were registered from June-October. In total 41 crustacean species were identified. The caprellid Caprella penantis, traditionally associated to non-polluted areas, was more abundant on Tarifa Island (higher values of dissolved oxygen and pH) than in Algeciras (lower oxygen and pH). The gammarid Podocerus variegatus was dominant in Algeciras Bay while Hyale schmidti and Apherusa mediterranea were the most abundant on Tarifa Island. Among isopods, Synisoma nadejda was only found on Tarifa Island. When compared with literature of native algae of the intertidal and shallow sublittoral, the species richness of associated crustaceans was similar in A. armata and the natives. Very little is known about the influence of this algae on altering marine communities, so complete faunistic studies dealing with other groups such as polychaetes or molluscs are necessary to properly address biogeographical, ecological and management programmes dealing with this non-native species.     

观测空气污染的迄感仪器

光与气体和粒子之间的相互作用为对大气污染物的遥感提供了技术途径。这种技术现在正在变成现实,它避免了将仪器或取样器放入烟囱中的困难,允许用同样的传感器监测不同的污染源,并能够有效地大范围地进行监视。光学设备也能够对监测结果进行高速分析,并能够获取在特殊位置上有代表     

Plastic debris collars on juvenile carcharhinid sharks (Rhizoprionodon lalandii) in southwest Atlantic

Three juvenile Brazilian sharpnose sharks (Rhizoprionodon lalandii) caught in gillnets in southeast Brazil, southwest Atlantic, were found with plastic debris rings around their gill or mouth region. The rings caused severe abrasion on the sharks' tissues as the animal grew, the collars probably hampering normal feeding and/or ventilation since two of the collared individuals were emaciated. The rings were identified as detachable lid parts from plastic bottles, likely thrown overboard by fishery and/or recreation boats. As several carcharhinid shark species dwells and reproduce in shallow waters, the impact of discarded plastic debris likely is greater on this shark type.