石墨炉原子吸收法测定土壤金属元素的质量控制

为使石墨炉原子吸收法测金属元素准确可靠，对各测定程序和环节采取了消除干扰、测平行双样、测加标回收率、对照分析等措施。测定数据经统计分析，加标回收率在87．3％～115．2％范围内，平行双样相对偏差在12．3％以下，标准土样重复测定变异系数除镉（Cd）外均在5．9％以下，达到了分析测定的要求。     

Air quality assessment for land disposal of industrial wastes

Air pollution from hazardous waste landfills and lagoons is largely unknown. Routine monitoring of toxic air contaminants associated with hazardous waste facilities is difficult and very costly. The method presented in this paper would be useful for air quality assessment in the absence of monitoring data. It may be used as a screening process to examine the question of whether or not volatilization is considered to be significant for a given contaminant and also to evaluate permit applications for new hazardous waste facilities concerning waste volatilization problems.     

旋转射流破岩钻孔机理研究

综合利用实验方法和数值模拟技术,研究了旋转射流的结构特性及井底流场分布,证明了旋转射流具有三维速度,且其速度最高部分,集中在离开射流轴心一定半径的一环形区域上,射流呈扩散状,其冲击面积随喷距的增大而大幅度增加。旋转射流破岩钻孔的机理不同于普通圆射流,它以剪切破碎为主,伴以冲蚀、拉伸破坏和磨削等多种形式,因而具有很高的破岩效率。破岩首先从对应着射流能量最高的环形区域开始,并逐步向内、外扩展,形成凸锥状的孔底。研究表明旋转射流在破岩钻长连续孔眼方面具有极大的优势     

出舱活动过程中航天员的热舒适性分析

分析了出舱活动中航天员－ 服装系统的热平衡,阐述了影响航天员热舒适性的因素及热舒适性的评价标准,并对美国航天员舱外活动的冷应激的人体工程学问题进行了讨论。还指出了提高航天员热舒适性有待解决的几个关键问题。     

Air pollution assessment of toxic emissions from hazardous waste lagoons and landfills

The air quality impacts of hazardous waste disposal sites can be assessed on the basis of their contribution to each of the toxic contaminants. The purpose of this paper is to discuss the available methods of air quality assessment and their drawbacks. The need of air quality assessment is to assure that ambient concentrations of specific contaminants resulting from emissions will not exceed the acceptable levels for protection of public health and the ecosystem. Ambient concentrations of toxic contaminants are generally obtained by field measurements or air monitoring. However, field measurements and air monitoring of low-level toxic contaminants are costly and time consuming. As a result, most hazardous waste land disposal sites have not been adequately assessed. This paper describes current regulatory requirements in the United States for air quality assessment of hazardous waste land disposal sites. Emphasis is directed toward air quality assessment methodology. The paper also discusses emission predicting models based on the waste quantity and composition, scientific analysis of the waste conversion process together with meteorological conditions. The emission models are especially useful where emission cannot be reliably monitored or where a new disposal site is proposed.     

A comprehensive framework for assessing and selecting appropriate scaffolding based on analytic hierarchy process

Problem: Bamboo scaffolding has been widely used in South China, Hong Kong, and Southeast Asia for many years. Bamboo scaffolding is more economical, but its safety record is relatively poor. Conversely, metal scaffolding is more expensive, but its use in these regions has increased in recent years because it is relatively safe. The assessment and selection of the most appropriate type of scaffolding for a particular construction project is always a concern for project managers. Method: This paper suggests a comprehensive assessment framework that enables project managers to take a number of major quantitative and qualitative factors into consideration when making scaffolding decisions. This framework is based on the Analytic Hierarchy Process methodology and a survey among project managers in Hong Kong. Results: The research reveals that the overall performance of metal scaffolding is believed to be better than bamboo scaffolding. A sensitivity analysis has also been conducted to investigate the impact of various factors on the final decisions. Impact on Industry: The proposed assessment framework can be used as a supporting tool for project managers in the selection of scaffolding for their projects.     

大口径毛细管柱气相色谱法在聚酯废气组成分析中的应用

采用直接进样大口径毛细管柱气相色谱法，可同时测定聚酯废气中乙烯、乙醛、乙酸、2－甲基－1，3－二氧戊环、三聚乙醛等污染物含量。进样量为1mL时，方法对乙烯、乙醛、乙酸、2－甲基－1，3－二氧戊环、三聚乙醛的最低检出浓度分别为1.0mg/m^3,2.3mg/m^3,7.3mg/m^3,2.7mg/m^3,3.3mg/m^3，回标回收率为92.0%-97.9%，相对标准偏差为1.8%-2.9%。对某煤厂聚酯废气进行实测，取得了较为满意的结果。     

RELATIONSHIPS BETWEEN FLOOD FREQUENCIES AND RIPARIAN PLANT COMMUNITIES IN THE UPPER KLAMATH BASIN,OREGON1

ABSTRACT: This study was conducted in the Klamath Basin of southwestern Oregon to evaluate the dependency of riparian plant communities upon infrequent flooding. Plant communities were sampled with 1 m² quadrats along established cross‐sections. Data collected for purposes of hydraulic modeling included channel and floodplain elevations (i.e., cross‐sectional profiles) and water surface elevations associated with specific discharges. The elevational distribution of hydrophytic plant communities relative to modeled return periods provided the basis for establishing relationships between these variables for nine sites. Results indicate that, on average, a peak flow frequency of 4.6 years (range of 3.1 to 7.6 years) was needed to sustain riparian plant communities at seven of nine sites. At two sites, results indicated return periods of more than 25 years were needed; these results possibly were influenced by local geomorphic conditions (a narrow steep channel in one case and an incised channel in the other). Overall, these results tend to confirm a strong dependency of riparian plant communities on overbank flows.     

轴对称渐缩回转进口旋风器流场特性研究

将普通切向单进口旋风器改进为具有轴对称渐缩回转进口的旋风器，并采用5孔探针对其流场特性进行了试验研究，给出了其速度和静压分布并与普通切向单进口旋风器进行了对比。结果表明，采用轴对称渐缩回转进口增强了流场的轴对称性，有利于同时提高效率和降低阻力。     

灾害基本特性研究

本文从灾害的产生、成因、过程及后果等多个方面分析灾害的基本特性,并揭示这些特性在灾害研究与减灾防灾中的应用意义。