峨眉山大火成岩省太和花岗岩的成因及构造意义

攀西地区的太和花岗质岩体和赋存超大型钒钛磁铁矿矿床的辉长岩体在空间上共生,成因上均与峨眉山地幔柱头的上升密切相关。太和花岗质岩体主要由超碱质花岗岩和石英正长岩及少量正长岩组成;富含高场强元素并具高Ga/Al值（3.74~5.63）,显示典型A型花岗岩的特征。花岗岩、正长岩和辉长岩的Nb/Ta和Zr/Hf值与洋岛玄武岩（OIB）的相应比值近似。花岗质岩石具较低的87Sr/86Sr初始值（0.7025~0.7049）和正的εNd（t）值（1.9~3.5）,与辉长岩的值相近[（87Sr/86Sr）i=0.7049~0.7052;εNd（t）=2.4~3.3]。太和花岗质岩体的εNd（t）为正值,显示地幔柱来源的底侵玄武质岩浆对其形成起主要作用。辉长质和花岗质岩石具相似的钕同位素组成,表明其母岩浆来自于同一源区。我们认为太和花岗质侵入体主要由底侵于下地壳的玄武质岩浆分异出的花岗质熔体侵位及随后经结晶分异而形成。因此,晚古生代时幔源岩浆底侵造成的地壳增生在峨眉山大火成岩省中表现极为显著。

湖北渔塘坝硒矿区发现超富集硒植物

通过野外调查在渔塘坝硒矿区首次发现了一种新的硒超富集植物-遏蓝菜（Thlaspi arvense L．）。调查结果发现，在自然生长条件下，一年生遏蓝菜叶子中富集硒可高达1427mg／kg，生物富集硒系数可高达68，地上部硒含量最低也超过了500mg／kg，生物富集硒系数最低也超过了10，表现为叶〉根〉叶柄的硒富集特征。多年生遏蓝菜叶、茎和根的硒含量分别为104～163；231～346；444～459mg／奴，生物富集硒系数为2．6～12．4，均大于1，显示出根〉茎〉叶的硒富集特征。尽管多年生遏蓝菜远没有一年生遏蓝菜的硒含量高，但远比一般植物硒含量高，达到了次生硒蓄积植物富集硒的水平，显示遏蓝菜植物可以超富集硒。渔塘坝遏蓝菜的发现将为研究硒在植物中的吸收、转化、富集机理以及提取有效抗癌有机硒化物和修复硒污染生态环境提供新的材料。

MVT铅锌矿床定年方法评述

MVT铅锌矿床的精确定年是建立可靠的成矿模式所必须解决的问题。文章评述了几种常用的定年方法，如古地磁法、^40Ar-^39Ar法、Pb—Pb同位素法、Rb—Sr法、Sm—Nd法、裂变径迹法，阐明了精确定年在研究MVT矿床成因中的作用，同时指出了各种方法的优点和不足。

羟铟石研究的新进展

羟铟石（Jalindite)产在云南个旧马拉格锡石－多金属矿床氧化带中，是一种铟的次生矿物，镜下观察白色透明，均质体。折光率1.725±0.002,α0=7.9514×10^-7mm。主要粉晶谱线（nm):0.395(10),0.279(8),0.178(10),0.163(8),0.1325(7),0.1260(7),0.1200(8),0.1065(10)。电子探针8个测试点平均含铟69.34%，元素分析含H1.78%。计算OH30.26%，不含C，S，N。矿物成因和实验研究表明，羟铟石中铟来源于原生硫化物矿物，铟在氧化铁矿石中主要呈独立矿物，其他形式均占极次要地位。

Simple derivatization method for sensitive determination of fatty acids with fluorescence detection by high-performance liquid chromatography using 9-(2-hydroxyethyl)-carbazole as derivatization reagent

A simple and sensitive method for the determination of short and long-chain fatty acids using high-performance liquid chromatography with fluorimetric detection has been developed. The fatty acids were derivatized to their corresponding esters with 9-(2-hydroxyethyl)-carbazole (HEC) in acetonitrile at 60 degreesC with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride as a coupling agent in the presence of 4-dimethylaminopyridine (DMAP). A mixture of esters of C-1-C-20 fatty acids was completely separated within 38 min in conjunction with a gradient elution on a reversed-phase C-18 column. The maximum fluorescence emission for the derivatized fatty acids is at 365 nm (lambda (ex) 335 nm). Studies on derivatization conditions indicate that fatty acids react proceeded rapidly and smoothly with HEC in the presence of EDC and DMAP in acetonitrile to give the corresponding sensitively fluorescent derivatives. The application of this method to the analysis of long chain fatty acids in plasma is also investigated. The LC separation shows good selectivity and reproducibility for fatty acids derivatives. The R.S.D. (n = 6) for each fatty acid derivative are <4%. The detection limits are at 45-68 fmol levels for C-14-C-20 fatty acids and even lower levels for

Mesoporous spinel MgAl2O4 prepared by in situ modification of boehmite sol particle surface: I Synthesis and characterization of the unsupported membranes

Mesoporous spinel membranes as ultrafiltration membranes were prepared through a novel sol-gel technique. By in situ modification of the sol particle surface during the sol-gel process, control of the material structure on a nanometer scale from the earliest stages of processing was realized. Nano-particles with a chocolate-nut-like morphology, i.e. spinel MgAl2O4 as a shell and gamma -Al2O3 as a core, were first revealed by HRTEM results. The formation of the spinel phase was confirmed by X-ray diffraction (XRD). N-2 adsorption-desorption results showed that the mesoporous membranes had a narrow pore size distribution. (C) 2001 Elsevier Science B.V. All rights reserved.

A combined DFT and SCRF study of solvent effects on 4-methyl-3-penten-2-one

The IR spectrum of 4-methyl-3-penten-2-one is interpreted with the aid of normal coordinate calculations within the Onsager self-consistent reaction field (SCRF) model, using a density functional theory (DFT) method at the Becke3LYP/6-31G* level. The solvent effects on the geometry, energy, dipole moment, and vibrational frequencies of 4-methyl-3-penten-2-one in the solution and in the liquid phase are calculated using the Onsager SCRF model. The calculated vibrational frequencies in the liquid-phase are in good agreement with the experimental values. The solvent reaction field has generally weak influence. For the two main bands of C=C and C=O mixed vibrational modes, small frequency shifts (5-6 cm(-1)), but relatively large changes in IR intensities (up to 101 km mol(-1) in the liquid phase) are found. (C) 1999 Elsevier Science BV. All rights reserved.