煤与瓦斯突出预测技术研究现状及发展趋势

对矿井煤与瓦斯突出预测方法的研究现状及发展趋势进行了论述及分析。目前我国大量使用的是钻屑量S、钻孔瓦斯涌出初速度q、瓦斯解吸指标Δh2 、瓦斯放散指数ΔP等钻孔静态预测方法 ,这些方法花费大量的人力、物力和财力 ,而且准确性较低。而声发射和电磁辐射等方法是很有前途的预测方法。未来煤与瓦斯突出预测的发展趋势是 ,利用声发射监测技术对变形破裂剧烈区域进行定位 ,利用电磁辐射监测技术工作面非接触连续预测 ,再结合现有的环境监测系统监测的瓦斯动态涌出对煤与瓦斯突出现象进行准确预测     

基于BCV模型与我国规范对中美场地类别的研究∗

场地类别是重要的工程参数,由于中国与欧美国家的场地类别划分存在很大不同,但中美场地类别对应关系又有一定的交叉现象。通过对比中美规范,提出我国场地类别换算V_(S30)的核心是需要"我国规范定义的计算深度到30 m之间沿深度的土层剪切波速分布模型"。然后根据目前已有钻孔深度小于30 m的V_(S30)换算公式,选择BCV模型为需要模型,并依据我国场地类别定义及参考实际工程钻孔资料,确定模型参数取值。最后,利用BCV模型得到更广义的与我国各场地类别相应的V_(S30)以及美国场地类别的对应关系。研究结果表明,我国各场地类别与相邻场地类别之间,其V_(S30)范围均出现严重的交叉、重叠现象。"在我国规范定义的计算深度到30 m,剪切波速大于500m/s的岩层不参与我国场地类别定义,但参与V_(S30)计算"与"等效剪切波速小且薄的覆盖土层会对V_(S30)范围造成大的影响"的双重影响,导致我国与以美国为代表的欧美国家关于场地类别的对应关系极为薄弱。     

Evaluating PM₂.₅ ionic components and source apportionment in Jinan, China from 2004 to 2008 using trajectory statistical methods

The mass concentrations and major chemical components of PM(2.5) in Jinan, Shandong Province, China from Dec. 2004 to Oct. 2008 were analyzed using backward trajectory cluster analysis in conjunction with the potential source contribution function (PSCF) model. The aim of this work was to study the inter-annual variations of mass concentrations and major chemical components of PM(2.5), evaluate the air mass flow patterns and identify the potential local and regional source areas that contributed to secondary sulfate and nitrate in PM(2.5) in Jinan. The annual mean concentrations of PM(2.5), sulfate and nitrate in 2004-2008 were almost the highest in the world. The most significant air parcels contributing to the highest mean concentrations of mass and secondary ions in PM(2.5) originated from the industrialized areas of Shandong Province. Clusters with a lower ratio of NO(3)(-)/SO(4)(2-) in PM(2.5) originated from the Yellow Sea, while a higher ratio was observed in the clusters passing through Beijing and Tianjin. PSCF modeling indicated that the provinces of Shandong, Henan, Jiangsu, Anhui and the Yellow Sea were the major potential source regions for sulfate, in agreement with the cluster analysis results. Regional and long-range transport of NH(4)NO(3) played an important role in the nitrate concentration of Jinan. By comparing the distributions of secondary sulfate and nitrate over three years, enhanced emission control management before and during the 29(th) Olympic Games led to a discernible decrease in source contributions from Beijing and its environs in 2007-2008.     

废轮胎的热解及其产物分析

研究了废轮胎热解产生的三相 (气、液、固 )产率与裂解温度的关系 ,气相组成与温度的关系 ,以及氢氧化钠作为催化剂加入热解体系对三相产率和气体组成的影响 .实验表明 ,轮胎橡胶的热稳定性分为 :～ 200℃,200℃～300℃及300℃以上3个区域 .在200℃以上时 ,随着温度升高 ,固体产率减少 ,气体产率增加 ,液体产物的产率在 500℃左右出现一个峰值 .加入 4%NaOH作催化剂以后 ,在相同的温度下固态碳黑和液态油的产率均有所提高 ,而相应混合气的产率降低 .实验确定了所用混合胶粉主要为合成橡胶 .不同温度下热解所产生的液体产物的红外谱图及裂解色谱图表明 ,300℃时主要是助剂分解,400℃左右主要是聚异戊二烯(天然胶)开始裂解,600℃以上残留物开始裂解.     

Research progress on occurrence forms and microbial transformation of mercury北大核心CSCD

汞是一种高毒性且具有持久性的重金属污染物,汞污染的治理与修复在近几十年一直是国内外研究热点.了解微生物对汞赋存形态的转化作用,对汞污染的治理与修复具有重要意义.总结汞的不同赋存形态、毒性及对应的常用分析方法,其中甲基汞(methyl mercury,MeHg)是毒性最强的汞形态之一.环境中汞的化学形态能发生转化,尤其以微生物驱动的汞的甲基化、MeHg的去甲基化和汞的氧化还原最为常见.依据汞转化类型将汞转化相关微生物分为汞甲基化、MeHg去甲基化、汞还原、汞氧化等类群,将对应的汞转化作用机制分为基于hgcAB基因的汞甲基化、基于mer操纵子基因的MeHg去甲基化和Hg2+还原、胞内过氧化氢酶介导的Hg0氧化.微生物汞转化过程不仅受到pH和温度的显著影响,而且还受到汞的赋存形态和游离汞的浓度、微生物种/群结构与功能、矿物种类、中间体和次生产物及其交互作用的影响,基于此,提出正确客观表征汞的微生物转化过程需要综合分析微生物组和矿物组的变化规律及其交互作用的综合效应.针对酸性矿山废水(AMD)极端环境微生物汞转化研究的不足,未来的工作将聚焦结合多组学手段、同步辐射谱学和密度泛函理论(DFT)计算等分析技术研究汞赋存形态的微生物转化过程,分析和阐明汞转化中间体的键合作用方式和转化机制,从而为AMD汞污染的预防、治理和修复提供依据.(图2表2参107)     

建筑物震害的类比预测方法研究

在“同一场地上相似的两幢建筑物,未来具有相似的震害程度”的假设前提下,提出了如何利用一个地区的部分建筑物单体的震害预测结果,对这一地区的其它建筑物单体的震害进行预测的方法,并从结构抗震角度研究了如何用加权Ｈａｍ－ｍｉｎｇ距离度量两幢建筑物的相似程度。     

Development of lightweight aggregate from dry sewage sludge and coal ash

In this study, dry sewage sludge (DSS) as the principal material was blended with coal ash (CA) to produce lightweight aggregate. The effects of different raw material compositions and sintering temperatures on the aggregate properties were then evaluated. In addition, an environmental assessment of the lightweight aggregate generated was conducted by analyzing the fixed rate of heavy metals in the aggregate, as well as their leaching behavior. The results indicated that using DSS enhanced the pyrolysis–volatilization reaction due to its high organic matter content, and decreased the bulk density and sintering temperature. However, the sintered products of un-amended DSS were porous and loose due to the formation of large pores during sintering. Adding CA improved the sintering temperature while effectively decreasing the pore size and increasing the compressive strength of the product. Furthermore, the sintering temperature and the proportion of CA were found to be the primary factors affecting the properties of the sintered products, and the addition of 18–25% of CA coupled with sintering at 1100 °C for 30 min produced the highest quality lightweight aggregates. In addition, heavy metals were fixed inside products generated under these conditions and the As, Pb, Cd, Cr, Ni, Cu, and Zn concentrations of the leachate were found to be within the limits of China’s regulatory requirements.     

Size fractionation of organic matter and heavy metals in raw and treated leachate

This study characterized the organic matter and heavy metals in the leachate from two typical municipal solid waste (MSW) sanitary landfills in China, the recently established (3-year-old) Liulitun landfill and the mature (11-year-old) Beishenshu landfill, using a size fractionation procedure. The organic matter of all raw and treated leachate samples primarily existed in a truly-dissolved fraction with an apparent molecular weight (AMW) of <1 kDa, and its percentage decreased with an increase in overall AMW. The leachate from the newer landfill had a higher percentage of truly-dissolved organic matter. After anaerobic treatment, this leachate had a similar size fraction of organic matter to that seen for the raw leachate of the mature landfill. Biochemical processes had different removal efficiencies for various types of AMW organic matter, and the concentration of moderate AMW organic matter appeared to increase throughout these processes. Most of the heavy metals existed in a colloidal fraction (AMW >1 kDa and particle size <0.45 μm). The behaviors of different species of heavy metals had large variations. The size fractions of heavy metal species were significantly affected by treatment processes and landfill age, except for Zn. The concentration ratio of heavy metals to organic matter was maximal in the colloidal fraction and showed an inverse change to that seen for organic matter concentration changes caused by biochemical processes. Consequently, the pollution levels of heavy metals were substantially increased by treatment processes, although their concentrations decreased.