砷测定方法的机理

理论研究是做好实验的基础。只有从理论给予说明,才能充分发挥主观能动作用,以有效地排除实验中的异常现象,从而获得理想的实验结果。本文从实验方法、操作技巧等方面剖析了砷测定方法的机理。     

一种更加安全的密码技术——量子密码

信息安全技术备受世人关注,由于现有的加密方法存在着很多弊端,人们将目光转向了量子密码。根据量子力学中的海森堡不确定性原理,任何窃听者都无法窃听量子密码通信中的信息而不被发现,笔者正是从量子不确定性基本原理出发来研究量子密码技术的,结合量子密码协议在通信网络中的应用来探讨了在量子通信过程中量子密钥生成、分发的详尽过程及量子密钥的分发协议在通信中应该遵循的原则,介绍了当前实验研究的进展,分析了量子密码研究存在的问题,并针对这些问题提出了一些建设性意见,最后对量子密码的发展前景和方向进行展望。     

MPS型抑尘剂在兰尖铁矿道路的应用

通过对兰尖铁矿使用MPS型抑尘剂的概述,其良好的防尘性能、经济效益及社会效益必将为广大的市场所认同。     

Application of nanobalance technique and principal component analysis for detection of the soil fumigant Telone residues in the air

Quartz crystal nanobalance (QCN) technique is considered as a powerful mass sensitive sensor for monitoring of materials in the sub-nanogram level. In the current study, a method based on QCN technique developed to determine Telone in air. Various coating materials including methyl phenyl silicon, 75% phenyl (OV25) and molecularly imprinted polymer (MIP) were employed. The frequency shift of OV25-modified quartz crystal was found to be linear against organohalogen compounds [Telone (soil fumigant), Koril (Herbicide), Endosulfan (organochlorine insecticide) and Chloroform (solvent)] concentrations in the range of 2.4 to 48 mg L^?1 for Telone vapor and 4.8–24 mg L^?1 for three other vapors. The correlation coefficients for Telone, Koril, Endosulfan and Chloroform were 0.992, 0.996, 0.989 and 0.991, respectively. The principal component analysis was also utilized to process the frequency response data of the organic vapors. Using principal component analysis, it was found that more than 93.85% of the data variance could still be explained by use of two principal components (PC1 and PC2). Subsequently, the successful discrimination of Telone and other compounds was quite possible through the principal component analysis of the transient responses of the OV25-modified electrode. In the second method, a molecularly imprinted polymer-coated sensor for Telone was developed. Molecularly imprinted polymer coated quartz crystal (MIP-QCN) showed a selective response to Telone and gave a linear relationship between frequency shift and amount of Telone from 1 to 48 mg L^?1. In this investigation, the proficiency of MIP-QCN and OV25-modified QCN sensors were compared.     

我国环境法确立风险预防原则的思考

环境风险预防原则是应对环境风险日益凸显的重要原则。通过对环境风险预防原则的分析,发现环境风险预防原则在我国确立中还存在着对其研究程度不够、混同于"预防为主,防治结合"原则以及仍惯于事后执法的传统思维等问题。面对挑战,应多措并举推进环境风险预防原则建设,例如确立环境风险预防原则作为环境法基本原则,转变举证责任主体的机制、建立信息公开等与风险预防原则相关的法律制度,拟采过错责任为风险预防的归责原则,从而预防和遏制环境风险的产生与扩散。     

Ecological knowledge and North Sea environmental policies

In an analysis of North Sea eutrophication science and policies, focusing on the period 1980–2005, it was investigated how scientific information was used in policy-making. The analysis focused on the central assumptions of the rational policy-making model, i.e. that scientific information can be used to formulate decisions, based upon objective scientific information (rational decision-making), and secondly, can support implementing these decisions (rational management). In general terms, the following was concluded:

• •More knowledge has increased rather than reduced uncertainty;
• •In order to handle the problem of dealing with complexity and uncertainty at the political level, a simplification of facts has occurred, in this case focusing on nutrients as the main cause of the problem, at the same time excluding other possible causes;
• •Both the limited scientific view (i.e. the nutrient view) and the exaggeration of the seriousness of the problem (impacts, scope) have been used as an authoritative basis for the justification of political decisions. Both were not supported by the majority of the scientific community;
• •New scientific knowledge, not in support of existing policies, has been excluded from the policy process;
• •The science–policy interface, mainly consisting of “civil-servant scientists”, that emerged and increased its influence over the period of investigation, has been the central element in the simplification and exclusion process.

The main lesson learned is that work at the interface of science and policy must be subject to democratic principles, i.e. be transparent and involving all parties with a stake in the issue under consideration.     

污水处理厂水质在线监测数据可靠性研究

水质在线自动监测系统近年已经开始应用于污水处理厂,在线监测数据的可靠性是污水处理厂推广和应用水质在线监测系统的前提和基础。以广州市某污水厂水质在线监测系统为研究对象,采用对比实验的方法并应用数理统计原理对实验结果进行分析,探讨水质在线监测系统数据的可靠性。经实验及结果分析,污水处理厂水质在线监测系统测得的数据真实可靠,可以用于对污水厂的监督和运行指导。     

挥发性有机废气生物处理技术研究进展

随着现代工业的快速发展,带来的挥发性有机废气(VOCs)排放到大气中,逐渐增加的VOCs已成为当今关注的重要环境问题之一。生物净化VOCs具有易操作、维护方便、净化效率高、运行费用低、安全性高、无二次污染等优点而备受世界各国的广泛关注。VOCs废气生物处理技术原理是将有机污染物在微生物作用下转换为无害或者低害的物质,而微生物则起到了至关重要的作用。综述了生物滤池、生物滴滤、生物洗涤3种净化工艺的原理和研究进展,将3种反应器优缺点进行了对比;最后论述了该技术当前存在问题及发展趋势。     

客车上顶内板冲压工艺及模具设计

论述了工艺分析在模具设计中的主导地位,着重指出冲压工艺方案的合理性是设计好模具的首要条件.并介绍了模具结构、工作原理及模具的使用情况.     

环境区划若干问题探讨

环境区划的理论基础是社会-经济-自然复合生态系统理论,持续发展论和区域科学理论.其区划的原则包括:①区域环境结构和功能的相近性和差异性;②相关自然区划或经济区划成果继承;③行政单元相对完整;④便于环境管理;⑤区划界面原则.该文还指出环境区划与环境规划的差异,提出需要探讨的若干问题. ·