Alumina-supported catalysts for propane oxidative dehydrogenation from mixed VXM(6−X)O19 (M=W, Mo) hexametalate precursors

γ-Al₂O₃ supported vanadium oxides were modified by tungsten and molybdenum oxides in order to improve dispersion and selectivity towards olefins in propane oxidative dehydrogenation (ODH). Both vanadium–tungsten and vanadium–molybdenum catalysts were obtained by adsorption of mixed isopolyanions (VW₅O₁₉⁵⁻, V₂W₄O₁₉⁴⁻, VMo₅O₁₉⁵⁻ and V₂Mo₄O₁₉⁴⁻) from aqueous solutions. The isopolyanion solutions were characterized by UV-Vis and ⁵¹V NMR spectroscopy. Vanadium, vanadium–tungsten and vanadium–molybdenum precursors and catalysts were also characterized by UV-Vis (diffuse reflectance) and solid state ⁵¹V NMR spectroscopy. An improved selectivity to propene in the presence of tungsten and molybdenum in VO_x/γ-Al₂O₃ was observed and attributed to dilution of vanadium by tungsten or molybdenum oxides on the γ-Al₂O₃ surface.     

无油分子泵机组的组装

介绍了将ALCATEL公司生产的一台ATPl00涡轮分子泵、一台MDP50ll牵引分子泵及一台VRC公司生产的lBy6型干泵组装成无油分子泵机组的过程。文中给出了泵间配合的计算、机组方案的设计、连接管路、仪器支架的设计及选择。本机组所采取的设计方案使三个泵都最大限度地发挥了优点避免了缺陷，较好地满足了使用要求，为今后选购单泵和组装无油分子泵机组提供了可靠的理论和实验依据。     

锂离子电池用聚合物电解质的最新进展II.含液聚合物电解质

由于干态聚合物电解质目前还不能满足聚合物锂离子电池的应用要求,人们致力于开发含液体增塑剂的聚合物电解质,包括凝胶型和微孔型两类体系。本文综述了含液聚合物电解质的最新进展,重点论述了各种新体系和新方法。     

Volumetric Change and Surface Properties of Temperature-Sensitive Polyvinylalcohol (PVA) Hydrogel

Polyvinylalcohol (PVA) polymer gel is a temperature sensitive polymeric gel, with a critical transition temperature (with H₂O) of 310 K. At higher than 310 K, this temperature sensitive polymer gel shrinks because of discharging water, whereas at lower temperatures, the gel swelled because of absorbing water. The reversibility of the gel's volume change was confirmed by temperature swing. The adsorption behavior of an organic compound onto the PVA polymer gel in water was tested at various temperatures. The amount of adsorbed organic compound increased remarkably at temperatures higher than about 310 K. Then, it was confirmed that the organic compound in PVA polymer gel could be reversibly adsorbed and desorbed by a temperature change between 293 and 323 K. The mechanism of adsorption of the organic compound onto the PVA polymer gel could be explained by hydration and dehydration of polymer gel.     

SJ—YⅡ—5型高爆速高威力水胶炸药的研制

文章简要分析了我国目前在中硬岩石爆破中工业炸药的使用情况，介绍了山西兴安化学材料厂新研制的一种适用于硬岩爆破的高爆速、高威力水胶炸药新品种，对其性能、爆破效果、经济实用性和安全性等进行了阐述。     

纳米级BaAl_2O_4微粉的制备和性质

分别用溶胶 -凝胶法、低温固相反应法 ,制得了纳米级BaAl2 O4微粉 ,用电镜观察了其形貌和粒径的大小 ,用X-射线衍射仪进行了物相分析 ,测定了其纯度与晶型 ,讨论了制备方法与粒度大小的相互影响     

Intramolecular crosslinking of poly(vinyl alcohol)

Poly(vinyl alcohol) is crosslinked in dilute solution (c=0.1 wt%) with glutaraldehyde. The reaction product is characterized by viscometry and gel permeation chromatography (g.p.c.). The intrinsic viscosity decreases with increasing degree of crosslinking and does not depend on temperature. G.p.c. reveals that the reaction product is not homogeneous, but consists of a mixture of particles with different sizes, possibly both intra- and intermolecularly crosslinked molecules. The intramolecularly crosslinked molecules are smaller in size than the initial polymer molecules and their size depends on the degree of crosslinking. They possess a narrow particle size distribution even if the initial polymer sample had a broad molecular weight distribution.     

Preparation, Characterisation and Catalytic Behaviour of a New TeVMoO Crystalline Phase

TeM_xMo_1.7O mixed oxides (M = V and/or Nb; x = 0-1.7) have been prepared by calcination of the corresponding salts at 600 °C in an atmosphere of N₂. A new crystalline phase, with a Te/V/Mo atomic ratio of 1/0.2-1.5/1.7, has been isolated and characterised by XRD and IR spectroscopy. This phase is observed in the TeVMo or TeVNbMo mixed oxide but not in the TeNbMo mixed oxide. The new crystalline phase shows an XRD pattern similar to Sb₄Mo₁₀O₃₁ and probably corresponds to the M1 phase recently proposed by Aouine et al. (Chem. Commun. 1180, 2001) to be present in the active and selective MoVTeNbO catalysts. Although these catalysts present a very low activity in the propane oxidation, they are active and selective in the oxidation of propene to acrolein and/or acrylic acid. However, the product distribution depends on the catalyst composition. Acrolein or acrylic acid can be selectively obtained from propene on Nb-free or Nb-containing TeVMo catalysts, respectively. The presence of both V and Nb, in addition to Mo and Te, appears to be important in the formation of acrylic acid from propene.     

控制图在土坝粘土填筑干密度控制中的应用

应用统计控制图法，选用平均值——标准差、平均值——极差控制图法，控制24^#坝粘土填筑干密度值及施工偶然异常波动，早期提出警报，以保证土坝的施工质量。