DC型液动冲击器及调试情况

介绍了用于大口径钻探的ＤＣ型无簧式双作用液动冲击器的结构和工作原理及设计计算结果，给出了其冲程，上阀程和上阀自由行程，下阀程和下阀自由行程的测量及调整方法。     

新型CIR系列冲击器的研制与使用

了我国潜孔冲击器的发展过程和近几年研制和生产的几种新型的ＣＩＲ系列冲击器的特点和工作原理。通过新旧冲击器的试验和现场使用对比，ＣＩＲ系列冲击器的部件寿命、穿孔效率的有明显的提高。     

液动冲击回转钻探技术的应用

由于水文钻探口径较大、地层复杂、孔径变化乡及工程质量要求高等难点，如何在水文钻探中应用液动冲击器，是一个亟待研究解决的问题。经过充分调研，我们选用了地矿部勘探技术研究所研制的YS-108型液动冲击器，并以其为基础开展了一定工作，取得了一定效果。     

YGQ—89／43型双作用冲击器微机电算分析

通过微机模拟仿真电算，分析ＹＧＱ－８９／４３型冲击器结构参数的变化对冲击器性能的影响规律，从而找出调节冲击器性能的有效方法，指导设计和生产使用。     

套管冲击器回转钻进法

套管冲击器回转钻进法是钻进覆盖层的最有效方法之一，广泛应用于地质勘探、采矿、建筑和水井钻凿。对它的主要设备、工作原理、操作注意事项及优点等作了全面介绍。     

长江口南槽季节性冲淤变化及其对河流入海水沙响应关系的初步研究

本文利用长江口南槽1989年12个月的实测地形图和大通站相应的水沙资料,采用GIS技术和数理统计技术分析了南槽的地形变化及其与河流来水来沙的关系.结果表明南槽水深与大通站各月平均流量、输沙率和含沙量之间有明显的相关性,说明河口冲淤对流域水沙变化有敏感响应;河槽的响应具有1～1.5月的滞后性.     

The Krakatau islands: The geotectonic setting

The Sunda Strait is located in a transitional zone between two different modes of subduction, the Java frontal and Sumatra oblique subductions. Western Java and Sumatra are, however, geologically continuous.The Krakatau complex lies at the intersection of two graben zones and a north-south active, shallow seismic belt, which coincides with a fracture zone along this seismic belt with fissure extrusion of alkali basaltic rocks commencing at Sukadana and continuing southward as far as the Panaitan island through Rajabasa, Sebuku and Krakatau.Paleomagnetic studies suggest that the island of Sumatra has been rotating clockwise relative to Java from at least 2.0 Ma to the present at a rate of 5–10h/Ma, and therefore the opening of the Sunda Strait might have started before 2 Ma (Nishimura et al. 1986).From geomorphological and seismological studies, it is estimated that the western part of Sumatra has been moving northward along the Semangko fault and the southern part of Sunda Strait has been pulled apart.Assuming that the perpendicular component (58 mm/yr; Fitch 1972) of the oblique subduction has not changed, we can estimate that the subduction started at 7–10 Ma. Huchon and LePichon (1984) also estimated that the subduction started at 13 Ma.Recent crustal earthquakes in the Sunda Strait area are clustered into three groups: (1) beneath the Krakatau complex where they are typically of tectonic origin, (2) inside a graben in the western part of the strait, and (3) in a more diffuse zone south of Sumatra. The individual and composite focal mechanisms of the events inside the strait show an extensional regime. A stress tensor, deduced from the individual focal mechanisms of the Krakatau group shows that the tensional axis has a N 130°E orientation (Harjono et al. 1988).These studies confirm that the Sunda Strait is under a tensional tectonic regime as a result of clockwise rotation along the continental margin and northward movement of the Sumatra sliver plate along the Semangko fault zone.     

西安市街道灰尘中铬、镉、铅赋存状态及环境效应

本文通过对街道灰尘中铬、镉、铅三种元素赋存状态研究、铬、铅在街道灰尘中以残渣态为主，镉以有机质结合态为主。虽然铬、铅、镉存在形式稍有差异，但其在街道灰尘中主要以矿物质的形态存在，说明其比较稳定，不易迁移转化，对环境的危害比较持久。在治理措施上应有早遏止微量元素向环境中排放，以免其与灰尘发生相互作用对环境造成长期的危害。     

矩阵可交换的条件及可交换矩阵的性质

通过对矩阵理论的深入研究，给出了矩阵可交换的条件，并得到可交换矩阵的一些性质。     

IAEA和中国的硫同位素参考物质的δ33 S、δ34 S值与32S/33S、32S/34S绝对比值

用六氟化硫法对IAEA-S-1、I.AEA-S-2、IAEA-S-3、IAEA-SO-5、IAEA-SO-6、GBW-04414和GBW-04415的δ33S、δ34S值进行了测定.用人工配制的同位素混合物和六氟化硫法对IAEA-S-1、IAEA-S-2、IAEA-S-3和GBW-04414、GBW-04415的32S/33S、32S/34S绝对值进行了标定.其结果对IAEA硫同位素系列参考物质的定值起到了关键作用.     

岩石破坏的机理再认识

岩石的各种强度准则一直是解释岩石或岩体破坏机理的主要理论。此外,从流变现象出发,通过数值模拟、实验对照、理论分析、进一步对岩石破坏机理的解释进行了探讨,认为受力岩石或岩体内差异流动变形也是导致岩石破坏的原因。     

The Himalayas

After splitting from Gondwanaland, India drifted northwards to collide with the Asian landmass about 40 million years ago. The intervening Tethys ocean was closed by northwards subduction beneath southern Tibet, and the collision created the Himalayan orogenic belt. Continuing northward movement of India at a rate of about 5 cm per year over the last 40 million years has caused it to indent Asia, and the resultant massive shortening is expressed by thrusting of the northern margin of India, by faulting and earthquakes in the Himalayas and China, by rifting and faulting in Tibet, and by the uplift of the Himalayas which is still continuing at rates of up to several millimetres per year.     

The local geologist 6: The fossil trade

What do you do if a professional collector starts fossicking in your favourite quarry? Call the police? English Nature? The local museum? Or perhaps nip round with the cheque book to get that crinoid you always wanted for the study wall? The correct answer could be any or all of these; professional fossil collecting is an activity with very real costs which are often outweighed by the benefits. It depends who's collecting what, where and when.     

The Cambrian metamorphic history of Tasmania: The Metapelites

The metamorphic complexes of Tasmania formed during the Cambrian (ca 510 Ma) as a result of rapid compression in a subduction zone setting followed by rapid exhumation, which brought various fault-bounded metamorphic complexes back to the surface in less than 5 Ma. The two highest grade complexes, the Franklin Metamorphic Complex, and the Port Davey Metamorphic Complex, experienced initial growth of metamorphic garnets at ～560°C, ～0.56 GPa. However, their subsequent metamorphic histories diverge, with the FMC displaying a marked increase in pressure (to 1.4 GPa at peak P/T), while the PDMC shows only a slight increase in pressure (to ～0.7 GPa). Both complexes show only a minor increase in temperature (～100°C) between initial garnet growth and peak metamorphic conditions. Rapid exhumation of these complexes can be accounted for by a slab-breakoff model. However, the difference in peak pressure between these complexes requires either continued subduction of the FMC while the PDMC had already begun its return towards the surface or that the subduction zone geometry resulted in significantly different pressures occurring contemporaneously within portions of the channel, which are not far removed from one another.