Characterization and electrochemical investigation of boron-doped mesocarbon microbead anode materials for lithium ion batteries

The structure and anodic performance of boron-doped and undoped mesocarbon microbeads (MCMBs) have been comparatively studied and the results obtained by XPS, XRD, SEM, Raman spectroscopy and electrochemical measurements are discussed. It is found that boron doping introduces a depressed d ₀₀₂ spacing and the larger amount of "unorganized carbon", which induces vacancy formation in the graphite planes and leads to a quite different morphology from that of the undoped material. Electrochemical charge/discharge cycle tests indicated that after boron doping the lithium intercalation was carried through at a somewhat higher potential, being attended by greater irreversible capacity loss. Electronic Publication     

Electrospray ionization tandem mass spectrometric study of the aconitines in the roots of aconite

Fragmentation pathways of aconitine-type alkaloids were investigated by electrospray ionization/ion trap multistage tandem mass spectrometry. Low-energy collision-induced dissociation of protonated aconitines follows a dominant first step, the elimination of the C(8)-substituent as acetic acid or fatty acid in MS(2) spectra. Successive losses of 1-4 CH(3)OH molecules, 1-3 H(2)O, CO, benzoic acid, and CH(3) or C(2)H(5) (N-substituents) are all fragmentation pathways observed in MS(3) and MS(4) spectra. By applying knowledge of these fragmentation pathways to the aconitines in the ethanolic extract of aconite roots, all the known aconitines were detected and also 23 unknown aconitine-type alkaloids, in which the lipo-alkaloids containing residues of 15C, 17C and 19C saturated or unsaturated fatty acids were characterized. These odd-carbon-number fatty acid substituents have not been reported previously.     

金属离子掺杂对TiO2光催化性能的影响

TiO₂光催化反应过程涉及光生电荷、电荷迁移、电荷在TiO₂表面的反应和溶液体相反应4个顺序相接并相互影响的步骤.在TiO₂中掺杂金属离子对以上4个步骤均有重要影响,合理的掺杂可有效地提高其光催化性能.本文综合了国内外此方面的最新研究成果,从提高TiO₂光催化性能和优化光催化反应的角度出发,在材料吸光能力、电荷扩散、表面反应、粒径和晶型等方面,全面地分析总结了金属离子掺杂的影响效果和规律性认识,并对TiO₂基光催化材料的金属离子掺杂改性研究的未来发展方向提出了建议.文中还简要介绍了相关的掺杂方法和材料表征手段.     

生物质在流化床中的空气-水蒸气气化研究

以流化床为反应器，对生物质的空气-水蒸气气化特性进行了研究。考察了一些主要参变量，如温度 (700 ℃～900 ℃)、水蒸气/生物质比(0～4.04)、空气当量比(0.19～0.27)以及生物质粒度(0.2 mm～0.9 mm)等对气化结果的影响。在实验研究的条件范围内，生物质产气率在1.43 m3/kg～2.57 m3/kg范围内变化，产气的低热值在6 741 kJ/m3～9 143 kJ/m3范围内变化。实验结果表明：较高的气化温度有利于氢的产生；但气化温度过高会使气体热值下降；与常规的空气气化相比，水蒸气的加入使生物质气化产气率显著提高，但水蒸气加入量过多使气化温度下降，产气率和产气热值降低；生物质颗粒粒度的大小对产气组分的分布和产气率均有影响，较小颗粒的生物质会产生较多的CH4、CO和较少的CO2。     

肝素化聚甲基硅氧烷-聚氧乙烯接枝物的合成及其体外抗凝血性能评价

以二甲基硅油接枝端羟基聚氧乙烯（ＰＤＭＳ ｇ ＰＥＯ ＯＨ）为基材，用二环己基碳二亚胺（ＤＣＣＩ）作脱剂，研究了羟基（ＯＨ）与肝素上的羧基（—ＣＯＯＨ）之间的脱水缩合反应，制备出肝素化的抗血栓材料ＰＤＭＳ ｇ ＰＥＯ Ｈｅｐ，并对其涂覆表面的肝素含量和体外抗凝血性能进行了初步评价．实验结果表明，肝素接枝的共聚物具有优良的抗凝血性能和一定的应用前景．     

多孔岩心的渗透性

The relaxation properties of water saturated in porous core are discussed and the distribution of proton transverse relaxation time and bi-exponential model of longitudiual relaxation time are obtained, which provide an illustration for two-model of fluids saturated in porous media. The cutoff value of T_1 based on relaxation specific property of fluids in porous core is adopted to improve the correlation between permeability and ?4T1b2.     

Two New Xanthone Glycosides from Polygala tenuifolia

Two new xanthone glycosides,polygalaxanthone IV and V were isolated from the roots of Polygala tenuifolia Willd. Their structures were established as 6-O-[α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranosyl]-1-hydroxy-3,7-dimethoxyxanthone(polygalaxanthone IV), and 6-O-[α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranosyl]-1,3-dihydroxyl-7-methoxyxanthone (polyga-laxanthone V),respectively, on the basis of chemical and spectral evidence.     

Infrared-optical properties of vapour-deposited metal films

Spectroscopic infrared ellipsometry was applied to determine the optical constants of thin metal layers deposited on dielectric substrates such as glass or CaF(2). The layers were produced by evaporating gold or silver in a vacuum, and the coverage, that is the deposited mass per area, was chosen in the range 80-1200 mg m(-2) for gold, which refers to thicknesses in the lower nanometer range; in the case of the specifically lighter silver, about half the coverage was applied. At low coverage a metal island structure is obtained, which gives rise to surface-enhanced infrared absorption (SEIRA). Depending on the coverage, the deposited films exhibit either dielectric or metallic optical properties. Atomic force microscopy and conductivity measurements complement the spectroscopic observation.     

L-proline promoted Ullmann-type reaction of vinyl bromides with imidazoles in ionic liquids

The Ullmann-type coupling reaction of vinyl bromides and imidazoles in ILs at 90-110 degrees C gave the corresponding N-vinylimidazoles in good to excellent yields by using L-proline as the ligand; the double bond geometry of the vinyl bromides was retained under the reaction conditions.     

新显色剂二溴对甲基偶氮甲磺光度测定稀土的研究和应用

研究了新显色剂二溴对甲基偶氮甲磺光度测定铈组稀土总量的方法，在酸性介质中，试剂与以铈组稀土为代表稀土形成蓝色配合物，在６４４ｎｍ有最大吸收，铈含量在０～１５μｇ／２５ｍｌ范围内符合比耳定律，方法应用于钢铁中铈组稀土总量的直接测定，发现其准确性和重视性良好。