Collaborative monitoring study of airborne particulate matters among seven Asian countries

Summary Seven Asian countries have been collaborating in collecting airborne particulate matter (APM) in their individual countries and analyzing them by neutron activation analysis as a common analytical tool. APM samples were collected into two fractions of fine and coarse grains (PM2 and PM2-10, respectively). Analytical data were compared from several viewpoints such as particulate sizes, locality of sampling sites (either urban or rural) and geographical location of participating countries. Chemical composition and their monthly variations as well as mass concentrations appear to be highly characteristic for individual sampling sites, suggesting that NAA data are suitable for evaluating the air quality in each site.     

Metrological role of neutron activation analysis. IB. Inherent characteristics of relative INAA as a primary ratio method of measurement

This is the second part of a paper which deals with the advantages and disadvantages of relative instrumental neutron activation analysis concerning traceability and uncertainty, and the current scope and possible future extensions of neutron activation analysis as a primary ratio method. The first part of this paper has been published in this Journal [1]. Received: 19 March 2001 Accepted: 2 October 2001     

A New Efficient Synthesis of p-Nitrocalix[4]arene

A new efficient synthesis of p-nitrocalix[4]arene from calix[4]arene by using nitrogen dioxide is described.The compound is an useful intermediates for the introduction of other functional groups to obtain N containing substituted calix[4]arene.The reaction mechanism is briefly discussed.     

Studies on fluorenscence resonance energy transfer between CdS nanoparticles and DOCAI dyes

The water-soluble CdS nanoparticles were synthesized in aqueous solution. A novel fluorescence resonance energy transfer (FRET) system with CdS nanoparticles as energy donors and 3,30-diethyl-oxadicarbocyanine iodide (DOCAI) dyes as energy accepter has been developed.     

A novel three-component reaction for the synthesis of new 4-azafluorenone derivatives

Reaction of arylidenemalononitriles, 1,3-indanedione, and mercaptoacetic acid or 4-methylbenzenethiol is successfully carried out using microwave heating. It is an efficient and promising synthetic strategy to build the indenopyridine skeleton.     

meso－四（4－磺酸苯基）卟啉与Co（Ⅱ）的显色反应的研究

本文研究了弱酸性介质中钴（Ⅱ）与ＴＰＰＳ４的显色反应条件。实验发现胺类化合物质子化后，不参与成络反应，而均能使ＴＰＰＳ４试剂的吸光度大大降低，从而提高了测定的灵敏度，Ｃｏ（Ⅱ）－ＴＰＰＳ４络合比为１：１，ε＿（４２６）＝３．５４×１０￣５，钴含量在０～５．０μｇ／２５ｍＬ范围内呈线性，并用于烟草、茶叶中痕量钴的测定，得到了满意的结果。     

胶束溶液中高氯酸二水(四胺)合钴(Ⅲ)配合物催化磷酸二酯水解的研究

本文合成了疏水性高氯酸二水（四胺）合钴（Ⅲ）配合物，研究了它与非离子表面活性剂Brij35形成的金属2胶束催化二（对硝基苯酚）磷酸二酯水解的动力学及其机理。结果表明此金属胶束对磷酸二酯水解的速率大约提高10^4倍，这主要是由于表面活性剂胶束的pH效应和浓聚效应所致，暗示着顺式二水类配合物形成的金属胶束是一个潜在的磷酸二酯水解剪切的催化剂。     

Synthesis of Obyanamide, a Marine Cytotoxic Cyclic Depsipeptide

Obyanamide 1 is a cyclic depsipeptide that was recently isolated from the marine cyanobacterium Lyngbya confervoides by Moore and co-workers1. This compound displayed a potent inhibitory effect on both KB and LoVo cells in vitro. Several structural analog…     

低温原子化石墨炉原子吸收法测定环境和生物样中的镉

本文描述了以氩/氢混合气体作保护气体,测定环境和生物样品中痕量镉的石墨炉原子吸收法。实验证明,与纯氩气作保护气体相比较用氩/氢混合气体作保护气体,能够降低镉的原子化温度(100℃),并且减少基体物质如MgCl_2和NaClO_4的干扰。这种改善氯化物和高氯酸盐基体干扰的机理,主要是由于氢的存在与基体中的氯形成高离解能的氯化氢,从而避免了通常在镉原子化之前形成易挥发的氯化镉而损失。用本方法测定了七种标准参考物质,结果与标准值一致,证明方法是可靠的。     

MgFe2O4-Fe2O3纳米粉体的软化学合成及电磁学特性

Nano-MgFe₂O₄-Fe₂O₃ magnetic powders were synthesized by citrate gel under microwave irradiation. The structure，particle size distribution，electromagnetic characteristics of nano-MgFe₂O₄-Fe₂O₃ were characterized by using TG-DTA, X-ray, electronic microscope, nano-size measurement and electromagnetism measurement apparatus。The results show that the product is a mixture of MgFe₂O₄ and Fe₂O₃ with average size of 44 nm, tanδ for the product is 0.265 and 0.610 at frequency of 1.0 GHz and 1.8 GHz respectively.