Thermodynamics of Binary and Ternary Copper-, Cadmium,and Indium-Containing Semiconducting Phases: An Electrochemical Study

Optimum compositions of ion-selective membranes in quasi-binary systems CuCl-CdCl₂, LiCl-CdCl₂, and In₂S₃-InCl₃ are selected by a method of coulometric titration in cells with solid electrolytes. Transport numbers for ions are close to unity for the optimum compositions; transport numbers for electrons are vanishingly small ( ≺10⁻³ to 10⁻⁴); the electroconductivity is equal to ≈ 10⁻³ S cm⁻¹ at 200°C; the diffusion coefficients for the current-producing component are on the order of 10⁻⁶ to 10⁻⁷ cm² s⁻¹. When using a solid electrolyte of the composition CuCl-CdCl₂, which contains 30 mol % CdCl₂, methods of emf and electroconduction reveal that the region of homogeneity of copper(I) selenide falls in the region of compositions Cu_1.33Se-Cu_2.67Se.__________Translated from Elektrokhimiya, Vol. 41, No. 6, 2005, pp. 721–727.Original Russian Text Copyright © 2005 by Leushina, Kolesnikova, Makhanova, Zlomanov.Published on the basis of a report delivered at the VII Meeting on Fundamental Problems in Solid-State Ionics (Chernogolovka-2004).     

High-resolution solid-state MAS 73Ge NMR spectra of some organogermanes

High-resolution solid-state magic angle spinning (73)Ge NMR spectra of some organogermanium compounds were measured. Most tetrasubstituted germanes with identical substituents exhibited signals except for one case. Tetrasubstituted germanes with two kinds of different but somewhat similar substituents exhibited broad peaks. Trisubstituted germanes failed to show signals, indicating the importance of symmetry around germanium.     

Characteristics of major dioxin/furan congeners in melted slag of ash from municipal solid waste incinerators

Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in slag of fly ash from three municipal solid waste (MSW) incinerators were analyzed to observe any changes in characteristics and distribution of their congeners by melting process. Actual concentration and Toxic Equivalent (TEQ) concentration profiles of 17 major congeners of PCDDs/PCDFs for gas, fly ash and melted slag were compared. The distributions of PCDDs/PCDFs in different streams macroscopically showed similarities with the generally known profiles for emission gas from a municipal waste incinerator. The total concentrations of PCDDs/PCDFs in off-gas and fly ash have been known to be a function of incineration conditions and of air pollution control device utilization; however, their normalized distributions were independent of such conditions. The concentrations of PCDDs/PCDFs in the melted slag of fly ash were not related to the concentrations of PCDDs/PCDFs congeners in fly ash but were rather a function of the melting furnace type and operation. The total amount of PCDDs/PCDFs in the melted slag of fly ash contained almost 150–27,000 times less dioxin than that in fly ash, however, the TEQ of dioxin in the slag was reduced by 435–43,500 times, which could enable them to be utilized as recycled construction materials. In normalized TEQ concentration profiles of 17 congeners of PCDDs/PCDFs, the ratio of PCDFs to PCDDs changed from 1.32 to 2.19 by melting, which showed relatively higher portion of furans left in melted slag than those in fly ash. By comparing reduction ratios of different congeners, PCDDs (dioxins) were relatively easier to destruct than PCDFs (furans) during melting process. The most difficult congener to destruct could be octa-chlorinated dibenzofuran (OCDF) among major congeners. For slag cooling methods, dioxin concentration in TEQ of slow cooled slag by air was four times higher than that of fast cooled slag by water. Thus cooling by water is more appropriate with the added beneficial effect of producing granules/particles, which can be utilized as roadbed materials.     

A practical fluorous benzylidene acetal protecting group for a quick synthesis of disaccharides

A new fluorous benzylidene acetal protecting group was regioselectively introduced into carbohydrates, deprotected under acidic conditions, and reused. Oligosaccharides were synthesized via regioselective conversion of the fluorous acetal group to the benzyl group by traditional reaction conditions. The fluorous compounds were easily separated from non-fluorous by-products by fluorous solid phase extraction.     

NMR studies on solid cyclohexaamylose inclusion compounds

Orthorhombic inclusion compounds of cyclohexaamylose with methanol,n-propanol, acetic acid and water as guest molecules were studied using¹³C and²H NMR techniques.¹³C chemical shifts were correlated with structural data, whereas²H NMR lineshapes were used to derive information on guest molecule motions.Issued as NRCC No. 25568. Presented in part at the 2nd International Symposium on Clathrate Compounds and Molecular Inclusion Phenomena, Parma, Italy, 30 Aug.–3 Sept. 1982     

The Use of Thermogravimetry in the Study of Rubber Devulcanization

Thermogravimetry was employed to study the changes occurring in rubber vulcanizates during devulcanization carried out by microwave treatment, a new promising method of recycling rubber waste. The thermogravimetric parameters T _i , T ₅ and T _p and the compositions of devulcanizates in comparison with vulcanizates were determined. The results obtained allowed estimation of the degree of destruction of the polymer chains in response to microwave treatment and permitted establishment of the most advantageous conditions of devulcanization in order to obtain the best properties of rubber devulcanizates for reuse in rubber processing. The results demonstrated that thermogravimetry is a very useful method for investigation and control of the microwave devulcanization process. This revised version was published online in August 2006 with corrections to the Cover Date.     

固体强酸催化剂S_2O_8~(2-)/ZrO_2-Al_2O_3-M_2O_3(M=Cr,Ce,La)的制备

固体强酸具有酸强度高 ,不腐蚀设备 ,不污染环境 ,与产物分离方便等特点 ,是一种对环境友好的催化剂。业已发现固体强酸对许多重要的有机反应如烃类异构化、傅克酰基化、傅克烷基化、酯化、缩合、聚合、氧化等具有良好的催化活性 ,可替代传统的浓 H2 SO4 及 Al Cl3、HF等高污染催化剂。在前文 [1]基础上 ,本文通过添加 Cr2 O3、Ce2 O3和 La2 O3对催化剂 S2 O2 - 8/Zr O2 - Al2 O3改进后制备出 S2 O2 - 8/Zr O2 -Al2 O3- M2 O3( M=Cr,Ce,La)系列固体强酸催化剂 ,用对乙酸和正丁醇的酯化转化率评价了催化活性 ,用 XRD、BET、流…     

Voltammetric Determination of Trace Amounts of 2‐Methyl‐4,6‐Dinitrophenol at a Silver Solid Amalgam Electrode

The voltammetric behavior of 2‐methyl‐4,6‐dinitrophenol was investigated by differential pulse voltammetry (DPV) at a nontoxic mercury meniscus‐modified silver solid amalgam electrode (m‐AgSAE). Conditions have been found for its determination by DPV at m‐AgSAE in the concentration range of 0.2 to 1 μmol L^?1.     

一氧化氮选择还原锡锆固溶体催化剂的结构特性

采用双股并流共沉淀方法制备了SnO2含量从10％至90％的锡锆体系DeNOx催化剂,用XRD、微区电子衍射、FT-Raman及FT-IR等技术深入研究了锡锆体系氧化物的结构及其随组成的变化规律.结果表明，由于Sn4＋与Zr4＋离子半径接近,SnO2与ZrO2易于形成固溶体,并随组成变化表现出不同的结构特征.纯ZrO2为单斜相,当少量Sn4＋（SnO2 ≤ 20％）进入ZrO2晶格时形成四方相富锆固溶体,Sn4＋起到稳定ZrO2四方相的作用;随着SnO2含量的增大,结构从无定形或微晶态的富锆固溶体(含SnO2 30～50％)经富锆固溶体与金红石结构的富锡固溶体在55％ SnO2含量的共存状态变化到具有金红石结构的富锡固溶体（SnO2 ≥ 60％）.FT-Raman和FT-IR光谱测试证明,Zr进入SnO2晶格使得Sn－O键的结合减弱,Sn离子上的有效正电荷减小,降低了SnO2对丙烯的燃烧能力,从而提高了对NO的还原活性.