川滇强震的回归—马尔可夫链联合预测

本文应用回归—马尔可夫链联合预测地震的方法,结合川、滇强震的特点,对川、滇强震进行了计算,并作了预测验证。结果表明,该方法对川、滇强震的预测效果较好。     

Tensile strength of rock by the double-punch method

Summary This paper presents an experimental study of the newly developed double-punch test method for determination of the tensile strength of rocks. The method for preparation of test specimens and test procedure is reported and discussed. Comparisons of tensile strength determined from double-punch and split-cylinder tests are also presented.With 5 Figures     

数字工程基础理论框架构建(1)

数字工程是信息化、数字化的虚拟工程。笔者从数字工程提出的背景和研究意义入手,构建了数字工程基础理论框架。首先介绍了数字工程的研究方法,内容包括研究思路、基本概念、研究对象、数字工程的特征、研究任务和数字工程方法论等。然后,阐述数字工程基础理论,内容有：数字工程的连续动态系统和离散动态系统,数字工程的随机性、自组织、简单巨系统和数字工程的复杂巨系统。     

Environmental history of an urban lake: a palaeolimnological study of Lake Jyväsjärvi, Finland

Sedimentary diatom frustules and chironomid remains, in addition to the chemical stratigraphy of 32 elements and organic pollutants such as resin acids, PCB, DDT and its metabolites, were studied from core samples taken from Lake Jyväsjärvi in Central Finland (64° 14 N, 25° 47 E). The sediment profile covered over 200 years, with the oldest samples representing a period of very low human interference. The town of Jyväskylä was established on the lake shore in 1837, and the lake received untreated municipal wastewater from the town up until, 1977. A paper mill started operations in 1872 and began discharging effluent into Lake Jyväsjärvi. In recent years this effluent loading has been reduced. Based on the biological and chemical properties of the sediment strata, five developmental phases were distinguished and named as follows: (1) a pre-industrial phase (approximately up until the 1860s); (2) a phase of early changes in the lake ecosystem (from the 1870s to ca. 1940s); (3) a phase of increasing eutrophication (from ca. 1950 to ca. 1965); (4) a phase of severe pollution (from ca. 1966 to the early-1990s); and (5) a phase of recovery, which proceeded more quickly during the late-1990s following long-term hypolimnetic aeration. It was estimated that the ecological status of the lake changed from good to moderate during the second phase. Due to the poor chemical status of the lake (including increased concentrations of harmful substances) and the pronounced changes in diatom and chironomid communities, the ecological status from 1950 to the early-1990s was classified as bad. The present ecological status, after a slow recovery of about 20 years, can be classified as moderate/poor. Chemical analysis of the sediment revealed that some elements (C, N, P, S, Ba, Cd, Cu, Fe, Pb, Ni and Zn) followed the known history of municipal waste water discharge into the lake, but Hg, Cr and persistent organic pollutants had different stratigraphies, and therefore mainly originated from other sources. Pronounced changes in profundal benthic communities (chironomids) started about 80 years later than those in diatoms, but later changes in chironomid assemblages were greater than those in diatoms.     

The acute and chronic effects of wastes associated with offshore oil and gas production on temperate and tropical marine ecological processes

A review of the acute and chronic effects of produced formation water (PFW), drilling fluids (muds) including oil-based cutting muds, water-based cutting muds, ester-based cutting muds and chemical additives, and crude oils associated with offshore oil and gas production was undertaken in relation to both temperate and tropical marine ecological processes. The main environmental effects are summarized, often in tabular form. Generally, the temporal and spatial scales of these studies, along with the large levels of inherent variation in natural environments, have precluded our ability to predict the potential long-term environmental impacts of the offshore oil and gas production industry. A series of critical questions regarding the environmental effects of the offshore oil and gas production industry that still remain unanswered are provided for future consideration.     

地震前低频事件的实验研究

介绍了几种强震前超低频事件的观测证据,并通过实验,研究了产生和传播机理。初步结果表明,微破裂的集结和断层的破裂起始会出现超低频脉冲,并透射到空气中形成次声波。塑性体的冲击或超临界流体的膨胀比脆性破裂更容易激发（超）低频波,且不伴随明显高频辐射成分。这样可以较为合理地解释震前“平衡”背景下的（超）低频事件。对实验中破坏前的低频脉冲给出了断裂力学解释。断裂力学的实验和膨胀－－扩容理论证明了震前会产生断层的张裂隙,从而为超临界流体提供了运移空间。流体在运移过程中突然涨缩会激发（超）低频辐射波。讨论了改进（超）低频事件的观测条件问题。     

水文循环的生物圈方面(BAHC计划)研究进展

在对国际地圈生物圈计划 (IGBP)的核心项目“水文循环的生物圈方面 (BAHC)”的基本目标和具体研究内容阐述的基础上 ,对 BAHC计划的国际、国内研究进展进行了详细介绍 ,并结合当前 BAHC计划的研究动态 ,对未来的 BAHC研究新的主题和内容进行了探讨。     

减灾增益, 强化地下水的研究和人才培养

本文简要介绍了我国地下水开发利用的成就;分析了日显突出的涉及地下水的灾害性问题;提出了进一步合理开发利用地下水、除害兴利而应当进行的11个方面的科学研究;强调了培养地下水领域高级人才的必要性.     

鄂尔多斯风沙滩地区土壤凝结水试验研究

鄂尔多斯风沙滩地区,常年干旱少雨,蒸发强烈,地下水资源消耗主要源于表土蒸发.而土壤凝结水的形成与转化又与表土蒸发之间存在着十分密切的关系.作者在内蒙古自治区乌审旗气象局院内,采用自制的笼屉式测渗仪进行土壤凝结水的观测试验研究,测量方法为称重法.并同步观测地表以上50cm处的空气温湿度以及地表和地表以下5cm、10cm、15cm、20cm、30cm、40cm、50cm处的土壤温度.通过试验,初步探明了该区土壤凝结水的形成与转化的基本过程,以及土壤凝结水的转化与气象因素之间的相关关系.     

河流梯级开发对生态环境影响的研究进展

河流梯级开发在满足社会需求的同时,还对区域生态环境具有一定的作用。针对河流水电开发对生态环境的影响,从河川流量、泥沙输移、水环境以及水生物等几个方面,将国内外的研究状况进行综合评述,并探讨了今后重点研究的几个方面:①如何应用可持续理念指导水资源开发与调度;②水利工程建设对河流水沙变化影响的量化研究;③失衡生态系统的自适应和自恢复机理研究;④水体富营养化最小临界流速研究;⑤如何通过水库联合调度,解决河流水电开发造成的环境胁迫问题的研究。