煤岩破落过程中螺旋滚筒的可靠性研究

为了研究采煤机螺旋滚筒的可靠性,以散体力学理论与刚柔耦合多体系统动力学理论为基础,利用EDEM软件,建立了采煤机截割部与煤壁耦合的离散元仿真模型,分析了牵引速度与装煤率之间的关系,提取了煤岩破落过程中螺旋滚筒的工作载荷并验证了其可靠性,通过ADAMS动力学仿真分析,并找出了滚筒在工作过程中的应力分布规律。研究表明:滚筒应力随着牵引速度的增大而增大,但装煤率出现先增大后减小的规律,在保证采煤机可靠性的前提下,牵引速度控制在8 m/min左右有较高的装煤率。     

Physiological testing of Mytilus galloprovincialis for the environmental assessing of coastal marine areas: a case study in Boka Kotorska Bay (the Adriatic Sea)

The aim of this work was to validate in the field certain measurement of the heart rate alterations of the bioindicator organism Mytilus galloprovicialis as a tool for ecotoxicological biomonitoring and assessment applications related to coastal and marine environment. The latter was determined by testing the mussels according to the method of functional loading (1-hour lowered salinity stress-exposure). The time of heart rate (HR) recovery (T_rec) and the coefficient of HR variation (CV_HR) in a group of tested animals were used as biomarkers for the assessment of their physiological state. It was found that the values of the biomarkers in mussels from our reference location were 1.3-1.5 times lower than in mussels from differently polluted coastal areas of the Bay. The study also included an investigation of the relationship between the mussel’s cardiac rhythm characteristics and the bioaccumulation of trace elements in their soft tissues, caused by chronic pollution. The conclusion was drawn that this approach to the physiological testing of mussels could be useful in developing a rapid and low-cost method for the assessment of the health of coastal ecosystems.     

企业生产安全事故应急救援预案编制技术的研究

企业编制生产安全事故应急救援预案是企业建立生产安全事故应急管理体系的基础工作,对于企业提高生产安全事故应急救援能力,降低企业生产安全事故损失具有重大意义。笔者在对广州发展油品经营有限公司南沙油库事故应急救援预案编制技术的研究基础上,进一步阐述了企业生产安全事故应急管理体系结构,指出了企业生产安全事故应急救援预案编制的总体思路,并从企业生产安全事故应急救援预案编制的技术层面,论述了企业生产安全事故应急救援预案的体系框架及文件要素,指出企业生产安全事故应急救援预案的体系框架可以由总预案和程序文件体系两大部分组成,文件要素可以由2个一级要素、18个二级要素和2 8个三级要素组成。笔者论述的企业生产安全事故应急救援预案编制技术已经在广东省数百家企业得到宣传应用,取得了良好的社会效益。     

基于Monte-Carlo随机有限元的火灾可靠性研究--以混凝土简支梁为例

通过对建筑火灾的背景分析和研究现状的回顾,指出了进行建筑火灾可靠性研究的必要性.介绍了蒙特卡罗随机有限元计算的基本原理、随机数的产生办法和模拟次数的确定,最后作者采用通用有限元程序ANSYS计算了混凝土简支梁在不同温度、保护层厚度和荷载下的火灾可靠性.     

火灾下预应力混凝土结构极限承载力计算方法

预应力混凝土结构多用在大跨、重载结构中,因此预应力混凝土结构的抗火性能应该更加引起人们的关注.在合理假定的基础上,采用二台阶模型作为混凝土高温强度的计算模型,分别对单面和三面受火截面构件的等效截面面积计算公式进行了推导,并通过大量有限元计算得到了不同耐火极限的300℃和800℃等温线的位置.最后对梁的受拉区和受压区位于火灾高温区的情形分别建立了火灾下预应力混凝土受弯承载能力极限状态的计算公式,该公式力学意义明确,具有工程准确度,简易实用.     

痕量分析中的分析空白

在痕量分析中，样品的玷污是极易发生的，通过对国内外文献调查，比较系统地阐述了由玷污而引起的正空白（分析空白）对分析结果准确度及检测下限的影响；指出了分析空白产生的原因主要由环境、试剂、器。及分析者对样品的玷污所引起；提出了检测和扣除空白值的正确方法及评价痕量分析数据的准则。     

可持续发展刍议

本文简述了环境与发展问题提出的背景，阐明了可持续发展的概念及内容，论述了我国实施可持续发展战略的必要性、推动我国可持续发展的主要措施及衡量可持续发展水平高低的基本要素。     

PRESENCE AND DISTRIBUTION OF TRACE ELEMENTS IN NEW JERSEY STREAMBED SEDIMENTS1

ABSTRACT: The distribution of trace elements in New Jersey streambed sediments is described with respect to physiographic provinces and major drainage areas. Samples were collected during 1976–1993 at 295 sites distributed throughout New Jersey. Copper, chromium, lead, and zinc were detected with the greatest frequency and at the highest concentrations of the elements. Concentrations of most trace elements were significantly higher in streambed sediments from the New England (glaciated) and Piedmont physiographic provinces - the provinces with the lowest and highest percentages of urban land use, respectively - than in sediments from the other provinces. High trace-element concentrations in the New England (glaciated) province reflect previous mining of extensive magnetite deposits, whereas those in the Piedmont province most likely reflect urban land use. Significantly lower trace-element concentrations in streambed sediments from the Coastal Plain are attributable to the low pH of the streamwater, the lack of iron and manganese available to form coatings that scavenge trace elements, and the relatively low percentage of urban land use in the province. Trace-element concentrations were related to land use, population, or point sources in the drainage basin specific to the sampling location by using logistic regression. Results of this analysis indicate a relation between arsenic and agricultural land use; chromium and physiographic province; and copper, lead, and zinc and population density.     

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。