静海地震台地磁加卸载响应比与邻区地震关系研究

研究分析了静海地磁台2002～2006年观测资料的加卸载响应比异常与邻区ML 4.0以上地震之间的关系,提出了适用于静海地磁台的地震分析预报异常形态特征和阈值判据.     

Estimation of peak relative velocity and peak absolute acceleration of linear SDOF systems

In the seismic analysis and design of structures, the true velocity and absolute acceleration are usually approximated by their corresponding pseudo-values. This approach is simple and works well for structures with small damping (say, less than 15%). When the damping of a structure is enhanced for the purpose of response reduction, it may result in large analysis and design errors. Based on theory of random vibration and the established mechanism of seismic response spectra analysis, a method is developed (1) to predict the relative velocity spectra with any damping ratio level directly from the 5% standard pseudo-acceleration spectrum; and (2) to estimate the peak absolute acceleration. The accuracy of both is validated by using two selected ensembles of ground motion records.     

The environmental impacts of pollutants generated by routine shipping operations on ports

The environmental impacts generated by shipping operations have increasingly become an important research topic, where its pollutants often pose negative externalities to natural habitats and economic losses to coastal areas. While the environmental impact costs generated by shipping disasters, notably large scale accidental oil spills, have been widely studied, hitherto, works dedicated to the assessment of environmental impact costs of pollutants generated by routine shipping operations remain scarce due to their relatively implicit nature and thus delays of consequential risks. Hence, by proposing an economic model and calibrating it to Port of Rotterdam, this paper assesses the environmental impact costs generated by routine shipping operations on ports. By shedding light on this important, but under-researched, issue critical to the well-being of the global shipping industry, this paper provides a decent framework for further research in sustainable shipping and port management for future generations.     

Multistage deformation of linked fault systems in extensional regions: An example from the northern Perth Basin,Western Australia

Linked fault systems identified in the northern portion of the onshore Perth basin comprise north‐striking normal faults, the dominant structures in the basin, and hard linkages—east‐striking transfer faults. The former are either divided into segments of distinctive character by, or terminate at, the transfer faults. The fault systems were initiated by west‐southwest‐east‐northeast extension in the Early Permian but were reactivated by subsequent rifting with approximately east‐west extension in the Jurassic. They were also reactivated by the oblique extension of northwest‐southeast orientation associated with Gondwana continental breakup in the Late Jurassic ‐ earliest Cretaceous. In addition to reactivation, older structures of the linked fault families controlled the development of younger fractures and folds. During the oblique extension, the linked fault systems define releasing bends, characterised by a rollover anticline in the hangingwall of the Mountain Bridge Fault, and restraining bends where contractional folds are sites of major commercial hydrocarbon fields in the basin.     

Rate and historical change of direct recharge from precipitation constrained by unsaturated zone profiles of chloride and oxygen‐18 in dry river bed of North China Plain

Quantifying of direct recharge derived from precipitation is crucial for assessing sustainability of well‐irrigated agriculture. In the North China Plain, the land use is dominated by groundwater‐irrigated farmland where the direct recharge derived from precipitation and irrigation. To characterize the mean rate and historical variance of direct recharge derived from precipitation, unsaturated zone profiles of chloride and δ¹⁸O in the dry river bed of the Beiyishui River were employed. The results show that archival time scale of the profile covers the duration from 1980 to 2002 (corresponding to depths from 5 to 2 m) which is indicated by matching the δ¹⁸O peaks in the isotope profile with the aridity indexes gained by instrumental records of annual precipitation and annual potential evaporation. Using the chloride mass balance method, the mean rate of the direct recharge corresponding to the archival time scale is estimated to be 3·8 ± 0·8 mm year^?1, which accounts for about 0·7% of the long‐term average annual precipitation. Further, the direct recharge rates vary from 2·1 to 6·8 mm year^?1 since 1980. Despite the subhumid climate, the estimate of recharge rates is in line with other findings in semiarid regions. The low rate of direct recharge is considered as a result of the relative dry climate in recent decades. In dry river bed, unsaturated zone profiles of chloride and δ¹⁸O combined with instrumental records could offer valuable information about the direct recharge derived from precipitation during droughts. Copyright © 2011 John Wiley & Sons, Ltd.     

自然金的化学分离方法

作者用物理方法和化学方法相结合分离了九个矿区的自然金,效果良好,其纯度一般达99％以上。X光、化学分析和物性测试表明,化学处理对自然金的物性、化学成分和结构无明显影响。文中分别对几种矿物组合的化学分离方法作了具体介绍。     

Blasting Technique and Process for Rock Ridge in a Wave Power Station

A technique of peripheral presplitting blast with multi-ignitions of millisecond detonaters is put forward in this paper based on the characteristics of ridge blast for wave power station, the main ridge blasting with deep hole smooth blasting and casting blast of inclined holes. The formula to calculate explosive charge is established. Finally, the theory and process of this technique for ridge blasting are discussed.     

天津蓟县盘山石英二长岩体的Rb—Sr同位素年龄及其地质意义

盘山的石英二长岩体曾一直被认为系燕山期侵入体,经Rb—Sr测定结果,其同位素年龄为235.152Ma,应属海西晚期。     

云南新平县双沟蛇绿岩稀土元素地球化学研究

双沟蛇绿岩中,变质橄榄岩的REE分布型式为LREE富集型,可能是富大离子亲石元素(LILE)组分交代造成的。地幔岩部分熔融生成的初始熔体LREE亏损,而辉绿岩和玄武岩则存在LREE亏损和富集两种型式,前者相当于N-MORB,后者相当于E-MORB。推测前者来源于亏损的软流圈地幔,而后者的地幔源区经历过一次富集LREE和LILE的事件。双沟蛇绿岩的REE特征暗示它可能形成于弧后盆地。