LC－NMR联用的现状与展望

介绍了ＬＣ－ＮＭＲ联用的现状．近年来ＬＣ－ＮＭＲ的快速发展表明这两种分析方法联用时所面临的主要技术障碍已经克服．以尿样中的代谢物为例说明ＬＣ－ＮＭＲ联用在临床检测和鉴定中的应用．     

区域沙漠对气旋暴雨过程影响的数值试验

本文利用一个中尺度三维数值模式，对下垫面气旋发展过程中的影响了进行数值模拟，初步研究了区域性下垫面特征的变化对梅雨锋气旋和暴雨的影响，其结果表明，沙漠引起的温，湿，风的变化导致一个发展成熟的江淮气旋在午后进入沙漠试验区后，气旋的移速减慢，强度增大，在试验区边界附近暴雨增强，而试验区中心附近则降水减小。     

Observation and study of latent tracks on the surface of HOPG induced by H ions

The topography and size of damage on the surface of HOPG (Highly Oriented Pyrolitic Graphite) bombarded by high fluence (1×10¹⁶ ions/cm²) of H⁺ ions were observed and studied. In this work, 457 STM images of each one with 9×9 nm² area were obtained. From 163 of these pictures visible damage was found. In these 163 STM images the diameter of most damage is from 0.2 to 0.8 nm. In this study the number density of visible damage is much less than the ion fluence. The probability of damage is only about 1.8×10⁻⁴. The possible mechanism of damage formation is also analyzed and discussed.     

柑桔皮中微量元素的ICP－AES测定方法研究

本文采用ＩＣＰ－ＡＥＳ定量测定柑桔皮精油及柑桔皮渣中微量元素。对４种柑桔皮精油及７种柑桔皮渣中硼、镉、铬、铜、铁、锰、钼和锌进行测定。８种微量元素的样品加标回收率为８６％－１０８％，并且在测定过程中有很好的重现性。本法快速、简便、准确     

Radiation preparation and swelling behavior of sodium carboxymethyl cellulose hydrogels

Sodium carboxymethyl cellulose (CMC) is a kind of degraded polymer under γ-irradiation. However, in this work, it has been found that CMC crosslinks partially to form hydrogel by radiation technique at more than 20% CMC aqueous solution. The gel fraction increases with the dose. The crosslinking reaction of CMC is promoted in the presence of N₂ or N₂O due to the increase of free radicals on CMC backbone, but gel fraction of CMC hydrogel is not high (<40%). Some important values related to this kind of new CMC hydrogel synthesized under different conditions, such as radiation yield of crosslinking G(x), gelation dose R_g, number average molecular weight of network M_c were calculated according to the Charlesby–Pinner equation. The results indicated that although crosslinked CMC hydrogel could be prepared by radiation method, the rate of radiation degradation of CMC was faster than that of radiation crosslinking due to the character of CMC itself. Swelling dynamics of CMC hydrogel and its swelling behavior at different conditions, such as acidic, basic, inorganic salt as well as temperature were also investigated. Strong acidity, strong basicity, small amount of inorganic salts and lower temperature can reduce swelling ratio.     

A HREELS study of the adsorption of formic acid on slightly oxidized Nb(110) surface

An investigation has been made on the adsorption and decomposition of formic acid on slightly oxidized Nb(110) surface (0/Nb atom ratio = 0.2) using high resolution electron energy loss spectroscopy (HREELS),and a corresponding surface reaction mode is given.At 140 K,formic acid of low exposure on such an Nb(110) surface decomposed to formate,which bonded on Nb in monodentate configuration,simultaneously some formate decomposed to CO,which adsorbed on the surface.Formic acid multilayers formed when the exposure was high.While the temperature was increased to above 190 K,multilayer formic acid desorbed,and the surface was covered with mon-odentate-bonded formate and CO.In the temperature range of 250-300 K,chemisorbed formate changed from monodentate configuration into bridging configuration and CO molecules disappeared.The decomposition of formate at higher temperatures led to the oxidation of Nb.The formate formed in the high exposure case was so stable that it did not decompose even the temperature wa     

Studies of protection of iron corrosion by rosin imidazoline self‐assembled monolayers

A type of rosin imidazoline (IM) has been synthesized using rosin acid and diethylenetriamine (DETA) as raw materials. The monolayers of IM were assembled on the surface of iron. The monolayers of the IM inhibitor were characterized by electrochemical impedance spectroscopy (EIS), electrochemical polarization curves and double‐layer capacitance. Surface analysis was carried out to establish the mechanism of corrosion inhibition of iron by X‐ray photoelectron spectroscopy (XPS) and scanning electron microscopy. The IM inhibitor showed good inhibition efficiency for iron in 0.1 M H₂SO₄. The inhibition mechanism of IM inhibitor was interpreted using molecular simulation. Copyright © 2006 John Wiley & Sons, Ltd.