Molecular activation analysis for iridium

Molecular activation analysis (MAA) of iridium in geological samples, based on a combination of a newly-developed chemical sequential dissolution method and radiochemical and instrumental NAA, was described to study the distribution pattern and chemical species of iridium in various fractions (soluble carbonate, metal, sulfide, oxide, silicate and acid-insoluble residue) of geological boundary samples, meteorites, ultrabasic rock and volcanic lava. The correlations of Ir with Au, Os, siderophile, chalcophile and lithophile elements were discussed. In addition, the role of kerogen and noble-nugget in the Ir enrichment was scrutinized. The MAA results of Ir favors a mixed effect of asteroid impact, volcanic eruption and post-depositional redistribution to interpret the extant Ir anomaly at Cretaceous-Tertiary boundary layer.     

液相色谱法测定DNA碱基比例及相关条件的优化

应用反相高效液相色谱法测定了鲑鱼精子ＤＮＡ的碱基组成比例，并就有关分析条件进行了优化选择。结果表明：在相关条件中，ＤＮＡ样品的水解条件、标准碱基溶液和ＤＮＡ水解液的ＰＨ值、液相色谱流动相的组成和ＰＨ值是影响各碱基色分离和峰形以及排除杂质干扰的主要因素，在优化选择的条件下测定，各碱基色谱峰分离完全、峰形好且不受杂质干扰，ＤＮＡ样品中各碱基加收量高。高检测信号衰减８倍时，各碱基的最小检测量低于５ｎｇ，     

Co—Mo／Al2O3催化剂的微结构

B_(302Q)型Co-Mo/Al_2O_3催化剂在制备过程中要经过一高温区,活性组分Co、Mo会与载体Al_2O_3发生反应,生成无活性的CoAl_2O_4,CoMoO_4和低活性的CO_9S_8。而活性相MoS_2晶化程度加快,使催化剂活性降低。不过B_(302Q)比C_(25-2-02)(美国),SKK(丹麦)及     

表面附聚薄壳型单分散高效阳离子柱填料的研制及其性能

 报道了一种新的表面附聚薄壳型阳离子柱填料的简易制备方法。首次合成了单分散高效阳离子柱填料。以10μm的单分散聚苯乙烯 二乙烯基苯(PSTDVB)微球为基球,对其表面季铵化,然后均匀附聚一层磺化的阳离子乳胶(0 2μm),即得到阳离子固定相。分别用碱金属及碱土金属离子对用该填料制成的柱的性能进行了测试,结果表明该柱填料对常见阳离子具有很好的分离效果、良好的重现性和低的检测限。     

Removal of mercury and fluoride from aqueous solutions by three-dimensional reduced-graphene oxide aerogel

Research on Chemical Intermediates - Three-dimensional reduced-graphene oxide (3-D RGO) hydrogel was synthesized by hydrothermal method from graphene oxide, de-ionized water, and oxalic acid...     

Sulfur‐Containing Chiral Bis(oxazolines) Tested in Copper‐Catalyzed Asymmetric Cyclopropanation

The novel C₂‐symmetric sulfur‐containing chiral bis(oxazoline) compound has been synthesized and characterized by X‐ray crystallography. Highly enantioselective and diastereoselective cyclopropanation reactions have been performed using the copper‐bis(oxazoline) catalyst.     

Recovering Ga(III) from coordination complexes using pyridine 2,6‐dicarboxylic acid chelation ion chromatography

Ion exchange chelation chromatography is an effective means to extract metals from coordination complexes and biological samples; however there is a lack of data to verify the nature of metal complexes that can be successfully analysed using such a procedure. The aim of this study was to assess the capability of pyridine 2,6‐dicarboxylic acid (PDCA) to extract and quantify Ga(III) from a range of environments using standard liquid chromatography apparatus. The PDCA chelation method generated a single Ga(III) peak with a retention time of 2.55 ± 0.02 min, a precision of <2% and a limit of detection of 110 μM. Ga(III) hydroxide complexes (highest stability constant 15.66) were used to successfully cross‐validate the chelation method with inductively coupled plasma mass spectrometry. The PDCA assay extracted 96.9 ± 1.2% of the spiked Ga(III) from porcine mucus and 100.7 ± 2.7% from a citrate complex (stability constant 10.02), but only ca 50% from an EDTA complex (stability constant 22.01). These data suggest that PDCA chelation can be considered a suitable alternative to inductively coupled plasma mass spectrometry for Ga(III) quantification from all but the most strongly bound coordinated complexes i.e. a stability constant of <15. Copyright © 2010 John Wiley & Sons, Ltd.     

Preparation and Properties of Some Wood-Plastic Cornbinations Involving Some Tropical Commercial Woods

Radiation-induced wood-polymer composites have been prepared using some tropical commercial woods. These included Kapur (Dryobalanop sp.), Kempas (Koompassia sp.), Red Seraya (Shorea sp.), White Seraya (Parashorea sp.), and Jelutong (Dyera sp.). The wood specimens were modified by impregnation with monomers and followed by exposure to gamma radiation. Monomer systems used were methyl methacrylate, methyl methacrylate with 5% dioxane, acrylonitrile, 60:40 styrene-acrylonitrile comonomer, vinyl acetate, and vinylidene chloride. The resulting composite specimens exhibited significant increases in hardness and compressive strength, the extent of which appeared to depend on the amount and type of polymer present. Dimensional stability increased when the woods were impregnated with polymethyl methacrylate and improved further to about 35% on addition of a swelling agent, dioxane. Wood-polyvinylidene chloride composites gave high fire resistance as opposed to wood-polymethyl methacrylate which showed increased flammability. A 4-fold decrease in weight loss was observed in the fire-tube and crib tests conducted. The impregnated polymers were not totally resistant to termites. The polymers, not being nutrients, reduced the number of survivals after a 90-d test period. Polystyrene-acrylonitrile appeared toxic to the termites.