Zr（Ⅳ）／PVA功能膜的膜催化酯化反应研究

在催化与渗透汽化分离技术相偶合的渗透汽化型膜反应器中，研究了羧酸酯的液相合成反应．实验中制备了两类具有强酸催化活性的ｚｒ（Ⅳ）／ＰＶＡ（聚乙烯醇）功能膜，采用管式膜方式，以乙酸正丁酯的合成反应为探针，对这类新型的催化反应技术在催化活性、分离性能以及分离对反应转化的影响等方面进行了探索性研究。从得到的结果看，膜催化酯化反应过程的反应条件和缓，转化率可达到９８％，反应的选择性为１００％．     

压力、温度和晶粒尺寸对Fe-N合金的合成及结构的影响

在 1× 1 0 - 3 Pa～ 4 GPa的压力和 5 80～ 930 K温度范围内 ,利用高压技术并结合机械球磨 ,研究了压力、温度和晶粒尺寸对α-Fe与非晶 BN的固态反应的影响 .发现高压和晶粒细化可以极大地促进α-Fe和非晶 BN的固态反应过程 ,α-Fe与非晶 BN发生固态反应的临界晶粒尺寸约 8nm.压力和温度对反应产物及其晶体结构有明显影响 .2 GPa和 80 0 K时 ,反应产物为具有正交结构的 Fe-N新相 ;在 3～ 4 GPa和 690～80 0 K时 ,可形成单一ε-Fex N合金相 ;而在 4 GPa和 930 K以上 ,反应产物由 Fe-N合金相转变为 Fe3B相     

Sm, Pr掺杂CeO2和CeMoO15基固体电解质的结构与性能

采用溶胶凝胶法制备了Sm和Pr掺杂的CeO2和CeMoO15基固体电解质, 通过X射线衍射(XRD)、拉曼光谱(Raman)、场发射扫描电镜(FE-SEM)等手段对氧化物结构进行了分析, 用交流阻抗谱测试了其电性能, 并比较了不同基体及其掺杂体系的结构与电性能. 结果表明, Ce6MoO15基掺杂体系的导电性能高于CeO2基掺杂体系; 元素Mo的加入使Ce6MoO15基材料的晶粒尺寸增大, 晶界相成分减少, 材料的晶界电导率增加, 600 ℃以下材料导电性能明显提高; Pr的掺入减小了材料的晶粒尺寸, 提高了材料的晶界电导率.     

Polystyrene-supported Benzyl Selenide: An Efficient Reagent for Highly Stereocontrolled Synthesis of Substituted Olefins

Solid-phase methodology has been rapidly and extensively applied to the preparation of small organic molecules recently1. It might be argued that selenoxide syn-elimination provided the principal impetus for the development of organoselenium chemistry. In addition, the required selenoxides are readily available from the oxidation of the corresponding selenides, which in turn can be prepared by the reaction of selenium-stabilized carbanions with various electrophilic substrates2. However, or…     

Study of Sb‐doped SnO2 Gray Ceramic Pigment with Cassiterite Structure

In this study, Sb_xSn_1?xO₂ (0 ≤ x ≤ 0.5) compositions were synthesized by the ceramic method from Sb₂O₃‐SnO₂ and Sb₂O₅‐SnO₂ mixtures and characterized by Differential thermal analysis (DTA) and thermogravimetric analysis (TG), X‐ray diffraction, UV‐V‐NIR spectroscopy and CIE L*a*b* (Commission Internationale de l'Eclairage L*a*b*) parameters measurements. Solid solutions with cassiterite structure were obtained at 1300 °C. These solid solutions are stable into glazes. From Sb₂O₃, light gray coloured materials were obtained. From Sb₂O₅, bluish gray coloured materials were obtained at 1300 °C/6h when x ≥ 0.3. Sb_xSn_1?xO₂ with 0.3 ≤ x < 0.5, T = 1300 °C and Sb₂O₅ might be established as compositional range, fired temperature and antimony precursor to obtain gray ceramic pigments in this system.     

Selectivity optimization for the capillary gas chromatographic analysis of bacterial cellular fatty acids

Summary The importance of selectivity in the capillary gas chromatographic analysis of the cellular fatty acids of micro-organisms is underestimated. The analysis on apolar silicone phases can lead to erratic elucidation of the fatty acid structure. Qualitative errors have been detected in commercially available standards on which computer matching identification techniques are based. Using highly polar capillary columns of the cyanopropyl silicone type, the errors could be elucidated. The exact identification of the hydrolysis products of bacteria is a must for chemotaxonomic studies applying chromatographic techniques. The fatty acid methyl ester profiles can also contain other chemical components which are very important taxonomic markers. Fatty aldehydes, for example, are main components in someClostridium species. Fractionation techniques are described for selective enrichment of fatty aldehydes and hydroxy fatty acids.Dedicated to Prof. Dr. A Liberti on the occasion of his 70th birthday     

Preconcentration of copper with multi-walled carbon nanotubes pretreated by potassium permanganate cartridge for solid phase extraction prior to flame atomic absorption spectrometry

A procedure for the preconcentration of copper was described in this paper using multi-walled carbon nanotubes (MWCNTs) oxidized by potassium permanganate as the adsorbent for the enrichment of trace copper in water samples. Important parameters, such as the sample pH, the concentration and volume of eluent, sample flow rate and volume, and interference of coexisting ions, were investigated. The obtained results indicated that proposed method possessed an excellent analytical performance. The linear range, the detection limit, and precison (RSD) were 1-100 ng/mL (R2 = 0.9993), 0.32 ng/mL and 2.88%, respectively. The results showed that copper could be adsorbed quantitatively on the pretreated MWCNTs with potassium permanganate, and proposed method was very useful in the monitoring of copper in the environment.     

固体表面化学发光分析 Ⅰ.不渗透阻挡技术的应用和研究

本文应用不渗透阻挡技术在固体基质上保持恒定的化学发光区域，实现了固体表面化学发光分析，并对固体表面化学发光特性，发光的均匀性和重视性，固体基质的选择和纯化等方面进行了研究，测定了１３种无机及生物活性物质固体表面化学发光的线性范围及检测限。由于此法克服了固体基质荧光分析和固体表面室温磷光分析的散射光背景的影响，获得了更高的信噪比和更好的检测限。     

Ternary and tetrahedral symmetry in hybrid fluorides, fluoride carbonates and carbonates

Tren amine cations and carbonate anions adopt a ternary symmetry while tetra amine cations are tetrahedral. The symmetry of these constitutive ions influences strongly the nature of the solids which crystallise from solutions. Large fluorinated aluminate polyanions with tetrahedral symmetry appear in the presence of tren amine, while infinite chains of AlF₆ octahedra are observed with tetra amine and that noncentrosymmetric structures are frequently encountered in rare earth fluoride carbonates.     

Preparation and Properties of Doped Lanthanum Gallate Film on a Ni/SDC Porous Anode Support

IntroductionIn intermediate-temperature solid oxide fuel cells(SOFCs),doped ceria with a fluorite structure anddoped lanthanum gallate(LSGM)with a perovskitestructure are commonly used as electrolyte materials.However,the former easily exhibits an electro…