北方蚕区夏秋蚕病的防范对策

夏秋蚕病是北方蚕桑生产上存在的主要问题,对蚕桑的危害不断扩大。为此,笔者根据多年调查研究,试验摸索出了北方蚕区夏秋蚕病的防范对策。     

减灾平衡点

文章依据经济学的原理提出了减灾平衡点的概念,并初步分析了它的特征及其实际意义。所谓减灾平衡点是指社会总体投资利益最大时减灾投资在社会总投资中所占的位置;此时,减灾投资利润率与社会正常生产投资利润率相当。     

FACTORS THAT AFFECT ACTIVATED SLUDGE PHOSPHATE RELEASE1

The activated sludge process can remove significant amounts of phosphorus from sewage, but the removal efficiency is usually significantly reduced by the release of phosphate back to solution during subsequent treatment steps. This research presents a study of soluble phosphate release from activated sludge with emphasis on defining the factors that affect such release and the actual release mechanisms. Laboratory units were used for experimental purposes. The experiments were designed to study the relationship between soluble phosphate release and various environmental factors such as redox potential (ORP), dissolved oxygen (DO), pH, solids concentration, solids destruction, and sulfate salt addition. The effect of substrate utilization on phosphate uptake and the relationship between uptake characteristics and subsequent phosphate release were also studied. The results show that some phosphate storage occurs during aerobic substrate utilization. Following substrate utilization, activated sludge phosphate release is directly related to the amount of biological stress the organisms are subjected to, and the mechanism of release is primarily cell lysis. The phosphate released per unit sludge under anoxic conditions is relatively constant. Under normal environmental conditions, neither ORP or pH change have a significant affect on phosphate release.     

DIGITAL SIMULATION OF THE EFFECT OF THERMAL DISCHARGE ON STREAM WATER QUALITY1

A modified transient version of the Streeter-Phelps model along with the energy balance equation is employed to analyze the effects of waste heat discharge from power plants on stream water quality. Analysis is also made to examine the effects of the upstream water quality and stream velocity on the downstream DO concentration level. The resulting coupled nonlinear hyperbolic partial differential equations representing the energy, BOD and DO concentrations are solved by the method of characteristics and simulated on a digital computer. Final numerical results indicate that the allowable quantity of thermal discharge does heavily depend on the upstream quality.     

Evaluation of Material Biodegradability in Real Conditions–Development of a Burial Test and an Analysis Methodology Based on Numerical Vision

This work validated a burial protocol for in situ testing and presents a robust, repeatable and time-saving technique to measure degraded areas in the sample, i.e. an image analysis method. 1440 specimens of degraded samples have been compiled in a data base. To this end, twenty samples presenting different levels of biodegradability (i.e. PHBV/HV, PLA, PCL, PCL-Starch, paper, PE, PE-Starch) were buried at 4 different locations and then disinterred at 4, 6, 9, 12, 18, and 24-month intervals. The biodegradation levels of these samples were determined by computing weight and area loss. Weight loss was measured after careful cleaning, whereas area loss was quantified using image analysis. Image analysis gives reliable information on visual pollution while only requiring a rudimentary and thus quicker cleaning of the samples.     

洗涤剂中的磷对环境的影响及对策的探讨

本文介绍了关于洗涤剂中磷对环境影响的两种典型观点和解决的办法,并从经济和环境的角度进行全面的分析,得出合理的结论和建议。     

居室放射性

本文介绍了放射性的来源,讨论了室内γ射线和氡及其子体,计算了相关的年剂量当量     

中国环保事业的回顾与展望

1970年至现在的30年,中国的环境保护事业大致经历了三个阶段:1970年至1978年,是中国环境保护的萌芽和起步阶段;1979年至1991年,是中国环境保护的奠基和成长阶段;1992年至现在,是中国环境保护的发展和壮大阶段。本文对中国环保事业的发展历程进行了回顾和论述,在此基础上,展望了环境保护的前景,抒发了梦想与期待。     

青岛市基础设施现状及主要自然灾害特征

概述了青岛市基础设施现状; 介绍了青岛市主要自然灾害（气象、地震） 特别是９０ 年代以来重要灾情, 并分析了特征; 最后给出了结论和建议。     

对中国防灾减灾立法体系的探讨

中国是自然灾害和经济、社会发展中人为突发事件灾害普遍、灾情严重的国家。灾害已直接影响和制约着国家的经济建设、社会发展和公众的安全。要把防灾减灾作为中国的基本国策。为此,必须长远规划和全面制定中国的防灾减灾立法体系,以适应２１世纪中国减灾安全与可持续发展的战略任务。本文就编制中国防灾减灾立法体系应遵循的指导方针、基本原则及方案的框架设想全面提出研讨建议。