两种空气自动监测系统的比较

国产长光程空气自动监测系统是中国自行研制的更为先进、更具自动化的系统，24h点式仪器是老式空气检测仪器，对这两种新、老仪器的比较可以看出在运行过程中的利弊。     

拉伸型渭河盆地地震孕育发生的构造模型

依据拉伸型渭河盆地块体周边断裂活动特征和块体运动特征,建立了盆地地震孕育发生的构造模型,旨在探索地震孕育发生的机制,为研究类似盆地地震孕育、发生及其分布规律和地震监测预报、震灾防御等各项防震减灾工作部署提供科学依据。     

南方水土流失区开发治理的思路——日本漆树引种

水土流失区采用综合防治措施取得了水土保持的良好综合效益，在市场经济条件下，在综合效益中，社会效益和生态效益比较，人们更重视经济效益。兴办经济实体，对水土流失区进行开发型治理，已成为人们的普遍要求。开发型治理模式是传统综合模式的提高，它要求有足够的基础投入；要有高素质的管理人才和技术，要选准开发对象，变水土保持重声势重规模为重管理重效益，因而其三大效益将有显著提高。宁都县漆树开发引种初露成效。     

沂沭推覆拼贴带与山东地区金伯利岩

本文就沂沭推覆拼贴带构造地质特徽结合山东地区金伯利岩的时空关系探讨进一步寻找含金刚石金伯利岩的可能性。     

碳同位素在油气地质研究中的应用和进展

稳定同位素地球化学是发展较快的学科之一，七十年代起被广泛应用于油气地球化学研究中。本文综述了碳稳定同位素在油气地质研究中的应用和进展，这些应用主要包括确定源油的形成环境与形成时代；进行油／油、油／源对比；判别天然气的成因类型并进行对比；判断天然气的成熟度。     

REHABILITATION OF WATERSHEDS WITH INCISING CHANNELS1

ABSTRACT: Channel incision is a pervasive problem that threatens infrastructure, destroys arable land, and degrades environmental resources. A program initiated in 1983 is developing technology for rehabilitation of watersheds with erosion and sedimentation problems caused by incision. Demonstration projects are located in 15 watersheds in the hills of northwest Mississippi. Watershed sizes range from 0.89 to 1,590 km², and measured suspended sediment yields average about 1,100 t km^-2-yr^-1. Water quality is generally adequate to support aquatic organisms, but physical habitat conditions are poor. Rehabilitation measures, which are selected and laid out using a subjective integration of hydraulic and geotechnical stability analyses, include grade controls, bank protection, and small reservoirs. Aquatic habitat studies indicate that stone-protected stilling basins below grade-control weirs and habitats associated with drop pipes and stone spur dikes are assets to erosion-damaged streams. Additional recovery of habitat resources using modified stone stabilization designs, woody vegetation plantings, and reservoir outlets designed to provide non-zero minimum flows is under investigation.     

MODELING MULTIPLE CRITICAL DEPTHS1

ABSTRACT: This paper explores the occurrence of multiple critical depths in one-dimensional computational models of open channel systems. The mathematical formulation is reviewed, including examination of the number of possible roots by Descartes' Rule. Governing equations and dependent variables are scrutinized using two compound cross sections. Occurrence tendencies are reviewed for singular channels. Critical flow is introduced as a tool to determine the existence and location of computationally based multiple critical depths. A strategy to manage multiple critical depths in existing one-dimensional steady or unsteady models is proposed.     

ENVIRONMENTAL IMPACT OF CHANNEL MODIFICATION1

ABSTRACT: The purpose of this literature review is to identify and quantify the effects of channelization and to examine the feasibility and acceptability of alternative methods of flood control. In the past 150 years, over 200,000 miles of stream channels have been modified. Channelization can affect the environment by draining wetland, cutting off oxbows and meanders, clearing floodplain hardwoods, lowering ground water levels, reducing ground water recharge from stream flow, and increasing erosion sedimentation, channel maintenance, and downstream flooding. Channelization reduces the size, number, and species diversity of fish in streams. In a wet climate, the fishery requires less than 10 years to fully recover. However, in the drier climates, the fishery may never fully recover. In general, channel modifications have performed as designed for flood abatement. The Arthur D. Little Study (1973) reported that direct benefits estimated during channelization planning have been conservative and that damage reduction has been impressive. Diking seems to be a viable alternative to channel dredging. Dikes minimize destruction of wetland and eliminate the need for removing vegetation from the existing stream banks.