共查询到20条相似文献,搜索用时 854 毫秒
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本文完善了电热板消解方法,增加了微波消解法.并将两者进行比对试验,实验结果表明对浸出液中总铬进行前处理消解时,电热板与微波消解法都适用,两种方法之间不存在明显的系统误差,准确度、精密度都符合质控要求. 相似文献
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建立了微波消解-原子荧光法测定环境空气汞的方法,探讨微波消解方法的前处理效果,进行准确性、精密性及实际样品测试等实验。本方法前处理简单、酸用量少,微波消解能使样品消解更完全,汞的加标回收率在95.0%~104.3%,回收率高。 相似文献
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微波消解-钼酸铵分光光度法快速分析水中的总磷 总被引:5,自引:0,他引:5
通过对微波前处理方法对水样中总磷进行消解分析的研究 ,探讨微波功率、加热时间、样品体积等对样品消解的影响 ,建立了微波消解样品测定的方法。测定结果表明与经典方法具有可比性 ,并具有操作简单、快速省时、节省成本、测定准确的特点。 相似文献
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微波消解/ICP-AES法测定土壤中的环境有效态金属元素 总被引:10,自引:0,他引:10
传统的土壤样品消解技术手续繁琐、费时,成为整个分析过程的薄弱环节;微波消解很好地解决了这一问题。采用微波消解技术处理土壤样品,以ICP-AES法测定Ag、As、Ba.Be、Cu、Mn、Mo、Ni、Pb、Sr、V、Zn,Al、Co 14种环境有效态金属元素。选择了HNO_3-HCL-H_20_2消解体系,确定了最佳微波消解功率和时间。方法精密度以相对标准偏差表示为1.20%~6.13%,准确度以回收率表示为79.6%~97.4%,与传统的酸解法处理样品相比较,相对误差在±120%以下,结果基本一致。微波消解处理土壤样品比传统的酸解法节省了约10倍的时间,具有快速、高效、清洁、用量少、背景值小等优点。 相似文献
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Paul Ney 《Die Naturwissenschaften》1981,68(12):597-605
Types of asbestos are distinguished not only by structure, chemical compositon, shape of aggregates, and length and quality of fibers, but also by its formation. Though consisting of quite common elements, deposits are formed only under very special conditions. Its unique combination of properties has created over 3000 fields of application (about 70% in asbestos cement). Great efforts have been made to substitute all types of asbestos by harmless, similarly cheap and versatile synthetic fibers, owing to the unquestioned carcinogenic properties of all asbestos dusts. However, development of such fibers has not made any remarkable progress until recently. Consequently risk to workers in mining and manufactoring, consumers, outsiders, and the environment should be kept as low as possible by intensifying precautions and diminishing emissions. 相似文献
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This work was conducted to evaluate whether Ca-bearing additives used during coal combustion can also help with the retention of some other elements. This work was focused on the evaluation of bottom ashes collected during four full-scale combustion tests at an operating thermal fluidized-bed power station. Bottom ashes were preferred to fly ashes for the study to avoid interference from condensation processes usually occurring in the post-combustion zone. This work focused on the behaviors of S, Cl, Br, As, Mn, V, Cr, Ni, Cu,Zn, W, and Pb. Strong positive correlations with CaO content in bottom ashes were observed(for all four combustion tests) for S, As, Cl and Br(R = 0.917-0.999). Strong inverse proportionality was calculated between the contents of Pb, Zn, Ni, Cr and Mn and CaO, so these elements showed association to materials other than Ca-bearing compounds(e.g., to aluminosilicates, organic matter, etc.). Somewhat unclear behaviors were observed for W, Cu, and V. Their correlation coefficients were evaluated as statistically "not significant", i.e., these elements were not thought to be significantly associated with CaO. It was also discovered that major enrichment of CaO in the finest bottom ash fractions could be advantageously used for simple separation of elements strongly associated with these fractions, mainly S and As, but also Cl or Br. Removal of5% of the finest ash particles brings about a decrease in As concentration down to 77%-80% of its original bulk ash content, which can be conveniently used e.g., when high As content complicates further ash utilization. 相似文献
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珊瑚钨锡矿硅质尾矿中Cd、As、Zn、F富集迁移及环境污染 总被引:1,自引:0,他引:1
硅质尾矿在释放中性矿山废水(NMD)时所伴生的多元素复合污染问题值得重视。本文以桂东北珊瑚矿尾矿作为研究对象,通过分析该尾矿的组构、元素富集及迁移特性,筛选出主要污染元素,并探讨尾矿胶结层对元素富集迁移的影响。结果表明:(1)该尾矿中Cd、As、Zn及F富集程度较高、可交换态含量(易迁移释放量)较大,是主要的污染元素,而Cu、Pb、Tl产生污染的可能性较小;(2)胶结层对重金属具有再富集作用,但其对可交换态Cd、As(Tl)再富集明显,而对可交换态Cu、Pb、Zn再富集则不明显。胶结层中次生伊利石、石膏等胶结物趋向于吸附富集活性可交换态Cd、As。这表明该尾矿可能迁移释放出含Cd、As浓度较高的NMD。研究表明,硅质尾矿风化释出NMD的同时,可能伴生Cd、As、Zn等重金属以及F的复合污染。 相似文献
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G. Vollmer 《Die Naturwissenschaften》1991,78(12):533-542
In order to say something substantial about the fundamental limits of machines (especially of computers) and of human calculations, we must explicate the concept of algorithm. Such an explication is provided by the Turing machine. Thus, problems have been discovered which cannot be solved algorithmically. For other problems there are problem-solving procedures, but no elegant algorithms. That men are fundamentally superior to machines has not been shown as yet. 相似文献
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Kurunthachalam Kannan Simonetta Corsoline Takashi Imagaws Silvano Focardi John P.Giesy 《Ambio-人类环境杂志》2002,31(3):207-211
我们曾对从意大利收集的金枪鱼、箭鱼、普通鸬鹚以及家燕体内的p,p'-DDE、多氯联苯同类物(PCBs)、多氯二苯-p-二恶英(PCDDs)、多氯二苯并呋喃(PCDFs)以及多氯萘(PCNs)浓度进行过测量. 相似文献
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Vine Edward L. Sathaye Jayant A. 《Mitigation and Adaptation Strategies for Global Change》2000,5(2):189-216
In this paper, we present an overview of guidelinesdeveloped for the monitoring, evaluation, reporting,verification, and certification (MERVC) ofenergy-efficiency projects for climate changemitigation. The monitoring and evaluation ofenergy-efficiency projects is needed to determine moreaccurately their impact on greenhouse gas (GHG)emissions and other attributes, and to ensure that theglobal climate is protected and that countryobligations are met. Reporting, verification andcertification will be needed for addressing therequirements of the Kyoto Protocol. While the cost ofmonitoring and evaluation of energy-efficiencyprojects is expected to be about 5–10% of a project'sbudget, the actual cost of monitoring and evaluationwill vary depending on many factors, including thelevel of precision required for measuring energy andGHG reductions, type of project, and amount of fundingavailable. 相似文献
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《Journal of Cleaner Production》2006,14(17):1557-1558