新试剂2－（6－甲基－2－苯并噻唑偶氮）－5－二乙氨基酚分光光度法测定微量镍

本文报道用新试剂２－（６－甲基－２－苯并噻唑偶氮）－５－二乙氨基酚（ＭＢＴＡＥ）分光光度法测定微量镍。Ｎｉ：ＭＢＴＡＥ＝１：２，ε＝８．１×１０４Ｌ／ｍｏｌ·ｃｍ，Ｎｉ２＋浓度在０～２２μｇ／２５ｍＬ范围内服从比尔定律。用于金属有机化合物中微量镍的测定，结果与理论值相符。     

Oxygen reduction on platinum electrodes in base: Theoretical study

Electrode-potential-dependent activation energies for electron transfer have been calculated using a local reaction center model and constrained variation theory for the oxygen reduction reaction on platinum in base. Results for four one-electron transfer steps are presented. For the first, O₂(ads) is predicted to be reduced to adsorbed superoxide, O₂⁻(ads), which dissociates with a low activation barrier to O(ads) + O⁻(ads). Then a proton transfer form H₂O(ads) to O⁻(ads) takes place, forming OH(ads) + OH⁻(aq). The second electron transfer reacts O(ads) with H₂O(aq) to form a second OH(ads) + OH⁻(aq). The third and fourth electron transfers react the two OH(ads) with two H₂O(aq) to form two H₂O(ads) + two OH⁻(aq). All three different surface reduction reactions are predicted to have reversible potentials in the −0.24 V(SHE) to −0.29 V(SHE) range for 0.1 M base and activation energies for the superoxide formation step are close to the experimentally observed range in 0.1 M base for the overall four-electron to water over the three low index (1 1 0) (1 0 0) and (1 1 1) surfaces: 0.38-0.49 eV at 0.35 eV respectively at 0.88 V(RHE). Predicted reversible potentials for forming O₂⁻(ads) are compared with estimates from the experimental literature. The difference between the acid mechanism, where the peroxyl radical, OOH(ads) is the first reduction intermediate, and the base mechanism, where superoxide, O₂⁻(ads) is the first reduction intermediate, is discussed.     

以稀土固体超强酸Gd^3＋-SO4^2-／ZrO2催化合成三氯水杨酸正戊酯

以不同配比的Gd3 -SO42-/ZrO2稀土固体超强酸合成三氯水杨酸正戊酯为探针反应,筛选出制备稀土固体超强酸Gd3 -SO42-/ZrO2的最佳工艺条件为:20 g ZrOCl2.8H2O1、.0%(质量分数)Gd2(SO4)3和0.8 mol.L-1H2SO4混合液,搅拌60 min后浸泡3 h,600℃焙烧3 h。以GSZ-1合成三氯水杨酸正戊酯的最佳反应条件为:72.8 g(0.3 mol)3,5,6-三氯水杨酸、17.6 g(0.2 mol)正戊醇、40 mL二甲苯和1.5 g的催化剂,电热套加热(105~110℃)回流反应2 h,酯化率可达93%。     

纳米助剂新进展

简述了纳米助剂的定义和制备，纳米氧化铝和纳米氧化硅助剂能显著提高涂膜的耐刮擦性而不影响光泽和透明性，纳米氧化锌助剂具有长效紫外线吸收性。     

氮化硅反应烧结的研究进展

氮化硅作为高温功能陶瓷性能优越，但将其制备成陶瓷零件比较困难，目前一般用反应烧结法制备氮化硅陶瓷零件。此外，反应烧结制备氮化硅陶瓷还具有成本低、烧结温度低、产品成型好、陶瓷高温性能好等优点。综述了氮化硅陶瓷反应烧结工艺流程和工艺的优缺点，着重介绍了氮化硅反应烧结在成型工艺、烧结工艺、原材料影响、后处理和陶瓷增韧等方面所取得的进展。     

Tri-pyramid Robot: Design and kinematic analysis of a 3-DOF translational parallel manipulator

3-DOF translational parallel manipulators have been developed in many different forms, but they still have respective disadvantages in different applications. To overcome their disadvantages, the structure and constraint design of a 3-DOF translational parallel manipulator is presented and named the Tri-pyramid Robot. In the constraint design of the presented manipulator, a conical displacement subset is defined based on displacement group theory. A triangular pyramidal constraint is presented and applied in the constraint designs between the manipulator?s subchains. The structural properties including the decoupled motions, overconstraint elimination, singularity free workspace, fixed actuators and isotropic configuration are analyzed and compared to existing structures. The Tri-pyramid Robot is constrained and realized by a minimal number of 1-DOF joints. The kinematic position solutions, workspace with variation of structural parameters, Jacobian matrix, isotropic and dexterity analysis are performed and evaluated in the numerical simulations.     

哈格曼乙酯与硝基乙烷在不同碱催化下的迈克尔加成反应

研究了在不同有机碱催化下,哈格曼乙酯和硝基乙烷经迈克尔加成合成3 甲基 3 (1′ 硝基乙基) 4 乙氧甲酰环己酮的反应。结果表明,氟化四丁基铵的催化效果最好,且当n(氟化四丁基铵)∶n(哈格曼乙酯)=1∶2时,合成产物3 甲基 3 (1′ 硝基乙基) 4 乙氧甲酰环己酮的收率达到最高值56%。     

Algal phagostimulants for marine herbivorous gastropods

Methanol extracts of the green algaUlva pertusa contain four kinds of glycerolipids that are active as feeding-stimulants for marine herbivorous gastropods. These compounds are digalactosyldiacylglycerol (DGDG), 1,2-diacylglycerly-4-O-(N,N,N-trimethyl)-homoserine (DGTH), 1-monoacylglyceryl-4'-O-(N,N,N-trimethyl)-homoserine (MGTH), and 6-sulfoquinovosyldiacylglycerol (SQDG). The various gastropods exhibit marked specificity, however, as young abaloneHaliotis discus respond to DGDG and DGTH at minute dosages of 20–30 g/sample zone, but do not respond to 300 g of SQDG, which is a phagostimulant for two other kinds of gastropods,Turbo comutus andOmphalius pfeifferi.Chemical Studies on Phagostimulants for Marine Gastropods. Part VI. For Part V, see Sakata et al. (1986b).     

采用高速剪切反应器生产超细氧化铋工艺探讨

利用硝酸铋溶液和碳酸铵溶液为原料，采用高速剪切反应器，500℃煅烧后可以生产出高纯、超细的氧化铋粉末。该方法制备出的氧化铋平均粒度0．71μm且粒度范围分布窄，颗粒形貌为类球形，晶相为纯α相，指标达到电子压敏陶瓷要求。由于粒度细小，可以在电子压敏陶瓷球磨工艺减少球磨工艺，并具有更好的分散效果。本文对超细的氧化铋粉末形成机理也进行了探讨。     

SO2-4/TiO2光催化降解邻硝基苯酚

采用硫酸溶液浸渍处理TiO2制得SO2-4/TiO2光催化剂.考察了光催化剂对邻硝基苯酚溶液的光催化行为.发现SO2-4/TiO2的光催化活性高于TiO2,浸渍液中H2SO4的浓度和催化剂的焙烧温度对SO2-4/TiO2的催化活性有一定的影响,H2SO4溶液的最佳浓度为0.5 mol·L-1,最佳焙烧温度为500℃.催化降解过程符合一级反应动力学规律.