物理监测的问题及发展趋势

本文介绍了环境物理监测现状及存在的主要问题和未来发展的趋势.     

Coherence in X-ray physics

Highly brilliant synchrotron radiation sources have opened up the possibility of using coherent X-rays in spectroscopy and imaging. Coherent X-rays are characterized by a large lateral coherence length. Speckle spectroscopy is extended to hard X-rays, improving the resolution to the nm range. It has become possible to image opaque objects in phase contrast with a sensitivity far superior to imaging in absorption contrast. All the currently available X-ray sources are chaotic sources. Their characterization in terms of coherence functions of the first and second order is introduced. The concept of coherence volume, defined in quantum optics terms, is generalized for scattering experiments. When the illuminated sample volume is smaller than the coherence volume, the individuality of the defect arrangement in a sample shows up as speckle in the scattered intensity. Otherwise, a configurational average washes out the speckle and only diffuse scattering and possibly Bragg reflections will survive. The loss of interference due to the finite detection time, to the finite detector pixel size and to uncontrolled degrees of freedom in the sample is discussed at length. A comparison between X-ray scattering, neutron scattering and mesoscopic electron transport is given. A few examples illustrate the possibilities of coherent X-rays for imaging and intensity correlation spectroscopy.     

绿色化学与可持续发展

绿色化学是一门从源头上阻止污染的化学,它吸收了传统化学化工、环境、物理、生物、材料和信息等学科的最新理论和技术,代表了化学化工科学理念的重大变革,具有可持续发展的意义。本文介绍了绿色化学的一般概念及绿色化学与环境保护的关系,从主要研究内容及发展现状和趋势等方面阐明了绿色化学是可持续发展的必由之路。     

物理化学与环境科学

环境化学从化学的角度来研究污染中的化学规律。物理化学的理论和方法被运用到环保中 ,为生态系统中能量流动提供理论依据 ,探索污染的形成机理 ,研究O3层的破坏机理 ,为环境检测提供了新技术     

绿色化学浅议

绿色化学是更高层次的化学，其产生是为了避免或减少化学过程对人类健康和环境造成的危害，由此出现的技术是环境友好的技术。绿色化学的发展能节省资源、减少环境污染，并将成为可持续发展战略的核心内容之一。     

分析化学的“准”与绿色环保

实现分析化学这门学科的任务和目的就是分析结果的准确性,"准"是分析化学的灵魂。从夯实理论基础、了解科技前沿、熟练操作技能、综合分析结果和绿色环保理念五个方面阐述实现"准",同时使分析化学成为绿色化学、环保化学。     

宇宙环境中的某些化学问题

本文讨论了宇宙环境中的化学概况,特别是宇航环境化学和宇航适应问题。     

高中化学导学案设计与研究

导学案的使用现已成为高中化学教学过程中必不可少的一部分,但无论是导学案模式,还是导学案内容的设计一直是一线教师所共同探讨的话题,教师希望通过实践研究找到高效的导学案模式,精心设计出不拘泥于教材,有着较强实用性的、富有创造性的一种设计,为教学服务,为学生服务。     

Chemistry and controversy: the regulation of environmental chromium

The regulation of chromium in drinking water and sludge illustrates some of the challenges of regulating a chemical with complex environmental chemistry in a dynamic regulatory environment. The controversies evoked in setting environmental standards for chromium reflect technical uncertainties and the conflicting values of affected parties including regulators, citizens potentially exposed to chromium pollution, polluting industries, and research scientists. Regulatory limits for chromium in water and sludge recognize the paradoxical nature of chromium chemistry but also illustrate how the use of risk assessment can alter the regulatory approach. The framework of rationality as described by Crawford-Brown is suggested as a useful tool for evaluating regulatory limits for environmental contaminants. Science-based policies are most rational when they reflect the characteristics of rationality with respect to the ends or objectives sought, the means chosen to achieve these ends, and the beliefs that substantiate the chosen means and ends. If scientific research is to be applied to regulatory or environmental policy questions, then the traditional focus on the rationality of empirically based scientific beliefs must be expanded to consider the focus of the research question and the methodologies used.     

近代分析化学进展

随着科技的进步，分析化学正经历着重大的变革。作者从我国分析化学的现状及分析化学的几个重要分支和交叉学科；生命科学分析，化学计量学，光度分析，色谱分析，电化学分析等方面阐述了近代分析化学的进展。     

发动机的绿色化学设计

发动机绿色化学设计以发动机化学设计概念和发动机化学反应器模型为基础,旨在实现发动机材料选择、能源利用和环境效应之间的最佳综合效益．发动机燃料系统绿色化学设计的范畴包括：汽油无铅化与汽油抗磨性,柴油低硫化与柴油润滑性,生态燃料与生态摩擦学,汽油机沉积物与汽油清净剂,柴油机颗粒（碳烟）与消烟助燃剂． 发动机润滑系统绿色化学设计的范畴包括：润滑油和添加剂与排放催化转化,润滑剂生物降解性与生物降解润滑剂,润滑油使用与质量监控． 发动机燃料／润滑系统材料绿色化学设计的范畴包括：催化助燃／补燃作用,低散热发动机高温润滑,发动机机械与化学材料制造． 发动机绿色效应的实现取决于发动机诸系统绿色化学设计问题的解决程度．     

Impact of crystalline and amorphous iron- and aluminum hydroxides on mechanisms of phosphate adsorption and desorption

Fourier-transform infrared(FT-IR) spectroscopic experiments were carried out during phosphate adsorption on highly crystalline gibbsite, poorly crystalline 2-line-ferrihydrite and amorphous iron–aluminum–hydroxide mixtures in the molar ratio 1:0, 10:1, 5:1, 1:1, 1:5, 1:10 and 0:1. The OH stretching vibrational bands were utilized to analyze changes in structural and surface OH groups during adsorption, because the position of characteristic P\O vibrational bands can shift depending on reaction conditions, pH or adsorbed phosphate content.Adsorption and desorption kinetics were studied at pH6 and different initial phosphate concentrations to achieve varying phosphate coverage on the mineral surfaces. For gibbsite the formation of AlHPO_4 and Al_2HPO_4 can be assumed, while for ferrihydrite, a FeHPO_4 or Fe_2PO_4 complex and the precipitation of FePO_4 with longer equilibration time were proposed.Fe_2HPO_4 or a Fe_2PO_4 surface complex was deduced for Fe-hydroxides, an AlH_2PO_4 surface complex was identified for Al-hydroxide, and both displayed either hydrogen bonds to neighboring hydroxyl groups or hydrogen bonds to outer-sphere complexes. Fe:Al-hydroxide mixtures with high Al ratios showed a low phosphate desorption rate, while ferrihydrite and the Fe:Al-hydroxide mixtures with high Fe ratios had almost negligible desorption rates. It was concluded that within the weakly associated amorphous FeO(OH) materials, FePO_4 precipitated, which was bound by outer-sphere hydrogen bonds. With high Al ratios, desorption increased, which indicated weaker phosphate binding of both inner-sphere and outer-sphere complexes and hence, either no or minor quantities of precipitate. Ferrihydrite showed a more rigid structure and a lower extent of precipitation compared to amorphous Fe-hydroxide.     

大气化学仪器测量进展

从平流层和对流层的大气化学过程入手，分析了研究各个反应所采用的测量手段；从当前大气化学的发展要求提出了理论研究和模式建立中对仪器测量手段的要求。并且从测量坪台这一角度分析了目前在大气化学领域使用的主要测量仪器和手段。     

催化技术对绿色化学的影响研究

绿色化学又称环境友好化学,它是在化学产品的设计、制造和应用过程中运用一套原理和理论来减少或者消除对有害物质的生产和利用的一门学科。绿色化学工艺的目标是用化学的技术和手段去减少或消除那些对人类健康有害的原料、产物、副产物、溶剂和试剂等的产生或应用。催化技术是绿色化学工艺研究及应用的重要手段,简要介绍了绿色化学与催化的关系、催化剂的研究进展及典型实例,并列举了几种新型绿色催化剂,详细分析了其环境友好特性。     

Cerium-modified amorphous manganese oxides for efficient catalytic removal of ozone

Manganese-based catalysts were widely developed for catalytic removal of ozone, and the low stability and water inactivation are major challenges. To improve removal performance of ozone, three methods were applied to modify amorphous manganese oxides, including acidification, calcination and Ce modification. The physiochemical properties of prepared samples were characterized, and the catalytic activity for ozone removal was evaluated. All modification methods can promote the removal of ozone b...     

环境分析化学的一个重要方向—形态分析的发展

结合一些典型环境污染研究的实例,重点概述了近年来国内在溶解金属的形态分析;固体形态分析;有机金属化合物的形态分析;以及非金属元素形态分析诸方面的进展。提出了当前应开展的主要研究课题。