Volumetric properties of H2O, D2O, and methanol in acetonitrile at 278.15—318.15 K

The densities of H₂O, D₂O, and MeOH solutions in acetonitrile with the solute concentrations up to 0.07 molar fractions at 278.15, 288.15, 298.15, 308.15, and 318.15 K were measured using vibrating-tube densimetry with an error 8·10^–6 g cm^–3. The limiting partial molar volumes for the H/D isotopomers of water and IaII in acetonitrile (V^– ₂ ) and the isotope effects in V^– ₂ and in excess molar volumes of acetonitrile—water mixtures were calculated. Molecules of H₂O, D₂O, and IaII form associates with acetonitrile molecules via hydrogen bonds. The associates have the packing volumes close to those in the individual solute. The water and methanol molecules were assumed to be incorporated into the acetonitrile structure without substantial changes in the latter. However, this process results in some compression of the system with a simultaneous increase in its expansibility.     

气相色谱-质谱联用测定苯乙烯中的阻聚剂对叔丁基邻苯二酚

 建立了气相 质谱联用 (GC/MS)测定苯乙烯中阻聚剂对叔丁基邻苯二酚含量的方法。苯乙烯样品直接进样 ,通过毛细管柱 (HP 1,30m× 0 32mmi.d .× 0 2 5 μm)分离 ,由电子轰击 (EI)源于选择离子监测 (SIM)模式下进行检测。结果表明 ,对叔丁基邻苯二酚含量在 5mg/kg～ 5 0mg/kg时线性关系良好 (r2 =0 9987) ,回收率高 ;与美国材料测试标准ASTMD4 5 90中的分光光度测量法比较具有操作简捷、准确度高的特点。     

A Theoretical Study on the Conductivity of Carbon Doped BNNT

From the changes in energy band, density of state (DOS) and electronic structure calculated by the DFT/B3LYP method, the conductivity of carbon doped boron‐nitride nanotube (BNNT), which is formed by C‐C bond substituting B‐N bond, was discussed. The results indicate that the substitution will strengthen the conductivity of the tube, and its semi‐conductivity might be adjusted by controlling the substitution.     

Theoretical study of reaction channels for the weakly bound complex systems created with HF,CO2, and various amines

This investigation conducted reaction channels of weakly bound complexes CO₂…HF, CO₂…HF…NH₃, CO₂…HF…NH₂CH₃, CO₂…HF…NH(CH₃)₂, and CO₂…HF…N(CH₃)₃ systems, using the Gaussian 98 package at the B3LYP/6‐311++G(3df,2pd) level. The syn‐fluoroformic acid or syn‐fluoroformic acid plus NH₃ or amine conformers are more stable than the related anti‐fluoroformic acid or anti‐fluoroformic acid plus NH₃ or amine conformers. However, the above‐mentioned weakly bound complexes are more stable than both the related syn‐ and anti‐type fluoroformic acid or acid plus NH₃ or amine conformers and their related decomposed into CO₂ + HF or CO₂ + NHR₃F (R?H, CH₃) combined molecular systems. Five reaction channels of the weakly bound complexes exist. Each channel includes weakly bound complexes and their related above‐mentioned systems. Moreover, each reaction channel contains two transition states. The transition state between the weakly bound complex and anti‐fluoroformic acid type structure (T₁₃) is significantly higher than that of internal rotation (T₂₃) between syn‐ and anti‐FCO₂H (or FCO₂H…NR₃) structures. However, the above‐mentioned T₁₃ can significantly decrease its energy by adding the third molecule NH₃ or NR₃ (R?H or CH₃). The more CH₃ that is substituted in NR₃ of the reaction channel, the lower the activation energy of the transition state in the system is affected. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005     

Intramolecular Diels—Alder reaction of 4-(N-furfuryl)aminobut-1-enes. New approach to the synthesis of 6,8a-epoxyoctahydroisoquinoline (3-aza-11-oxatricyclo[6.2.1.01,6]undec-9-ene) derivatives

The intramolecular Diels—Alder reaction of readily accessible 4-substituted 4-(N-furfuryl)aminobut-1-enes was studied and a new one-step method was developed for the synthesis of 6,8a-epoxy-1,2,3,4,4a,5,6,8a-octahydroisoquinoline (3-aza-11-oxatricyclo[6.2.1.0^1,6]undec-9-ene) derivatives. The [4+2]-cycloaddition proceeds stereoselectively to form exo-adducts. The influence of substituents at the nitrogen atom in 4-(N-furfuryl)aminobut-1-enes on the cycloaddition pathway was examined.     

Interactions of proteins with uniform colloidal hematite and chromium hydroxide particles. I. Adsorption

The adsorption of ovalbumin, -globulin, and lysozyme on uniform spherical hematite and chromium hydroxide particles in aqueous media has been studied as a function of the pH at a constant ionic strength. The uptake of ovalbumin and -globulin was greatest at their isoelectric points and differed little at 10^–2 and 10^–3 mol dm^–3 NaNO₃. The adsorption of lysozyme was strongly influenced by the ionic strength.The deposition of ovalbumin on hematite in the presence of Mg (NO₃)₂ was significantly greater than that with NaNO₃ under otherwise comparable conditions. Dialysis experiments with ovalbumin against magnesium nitrate solutions showed Mg²⁺ to be specifically bound to the protein.The shapes of isotherms indicated monolayer coverage for ovalbumin and multilayer coating for lysozyme for both adsorbents. The shapes of isotherms of -globulin on hematite point to a rearrangement of the protein on the particle surface, while a monolayer was found on chromium hydroxide particles.Supported by the NSF Grant CHE-9108420Part of a Ph.D. thesis     

Molecular structure of potassium [N,N′-bis(salicylideneamino)nitroguanidonate-N,N′,-O,O′]nickel(ii), the product of condensation of (salicylideneamino)nitroguanidine with salicylaldehyde on a Ni2+ ion template

The crystal structure of the product of the condensation of (salicylideneamino)nitroguanidine with salicylaldehyde on a Ni²⁺ ion template, K[Ni(C₁₅H₁₀N₅O₄)] · DMF, has been studied. It was established that a planar Ni complex, consisting of isolated [NiL]^– anions and solvated [K⁺ · DMF] cations, is formed. The negative charge of the anion is localized mainly on the O atoms of the nitro group. The nitroguanidine fragment of the ligand occurs in the tautomeric form, which was not reported previously.Deceased in 1995Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2273–2277, September, 1996.     

溶胶-凝胶法制备高取向Bi4Ti3O12/SrTiO3(100)薄膜

Bi4Ti3O12具有良好的铁电、电光等性能山、特别是Bi4Ti3O12薄膜很适合作永久性存储材料，也可用于电光器件问．在微电子学、光电子学、集成光学、集成铁电学等领域均有广泛开发和应用前景，国外已用溅射法、激光沉积法制备出c轴取向Bi。Ti3Ol。薄膜【’，＼山东大学用MOCVD法制     

Enhanced Acid/Base Catalysis in High Temperature Liquid Water

High temperature liquid water (HTLW), as an environmentally benign medium, has drawn increasing attention for organic chemical reactions and biomass conversion1-3. HTLW has a strong tendency to ionize and can act as an acid and/or base catalyst. In addition, HTLW can dissolve organic compounds to some extent allowing for a homogenous reaction within an aqueous phase. Extensive researches4-10 have been pursued on acid/base-catalysis reactions in HTLW without addition of acid or base. Howe…     

Preparation and Characterization of Nano-ZnFe2O4/TiO2 Films

The nano-ZnFe2O4/TiO2 films possess the functions of desulfurization and degradation for organic pollutants. The sols of ZnFe2O4/TiO2 were prepared by sol-gel method and coated on glass and porous ceramic by vertical coating and dipping-lift processes, respectively, and the samples were obtained after drying and sintering. The composition, appearance, absorption spectrum of the films, and the influence of the film on porous ceramic performances were analyzed using SEM, AFM, UV-Vis spectrometer, and mercury porosimeter, respectively, to determine the operation parameters of the multifunction porous ceramic elements for gas-purification.