Ignition and chemical mechanisms of volume combustion synthesis of titanium diboride

Reaction ignition and chemical mechanisms in volume combustion synthesis of TiB₂ via TiO₂–B₂O₃–Mg precursors were studied using in-situ differential thermal analysis, X-ray diffraction, scanning electron microscopy and thermochemical modeling. Mg–TiO₂ samples ignited at 607 °C through a sudden single step solid-solid reaction while Mg–B₂O₃ samples ignited at 810 °C after melting of magnesium. X-ray diffraction analysis revealed that reduction of TiO₂ occurs in multiple steps and forms intermediate compounds. Results showed that heat released from the first reaction between TiO₂ and Mg ignites the reactions between Mg, Ti and B₂O₃ resulting in the formation of TiB₂. Samples with larger TiO₂ particle size or a higher sample surface to volume ratio showed a two-step reaction behavior and the released heat in the first solid state reaction was insufficient for the propagation of the reaction throughout the sample. In addition, Mg₃B₂O₆ undesired by-product was formed as a result of this two-step reaction.     

天然产物天葵碱盐酸盐的全合成

以异香草醛为起始原料,经8步反应首次全合成得到了天然产物天葵碱。其结构经过~1HNMR、~(13)CNMR和高分辨质谱鉴定,与文献报道一致,为天葵碱及其衍生物的进一步研究奠定了化学基础。     

Controlled Synthesis of Polyions of Heavy Main-Group Elements in Ionic Liquids

Ionic liquids (ILs) have been proven to be valuable reaction media for the synthesis of inorganic materials among an abundance of other applications in different fields of chemistry. Up to now, the syntheses have remained mostly “black boxes”; and researchers have to resort to trial-and-error in order to establish a new synthetic route to a specific compound. This review comprises decisive reaction parameters and techniques for the directed synthesis of polyions of heavy main-group elements (fourth period and beyond) in ILs. Several families of compounds are presented ranging from polyhalides over carbonyl complexes and selenidostannates to homo and heteropolycations.     

发挥绿地系统的生态效应--邯郸市生态绿化系统研究

城市绿地系统生态效应的充分发挥，具有非常重要的意义。为此，论文在分析了邯郸市自然条件及生态绿化系统规划建设的基础上，提出了增加有效“绿量”；保护城市绿地生物的多样性；开放专用绿地；溶解公园；构筑多功能的防护林体系等五点新思路。     

基于岩层移动的"煤与煤层气共采"技术研究

研究了岩层移动对煤层气卸压运移的影响，结果证明，覆岩关键层的破断运动对邻近层煤层气涌出的动态过程起控制作用；覆岩主关键层位置将决定下保护层可能的最大卸压高度。     

基于绿色的煤机零件加工工艺方案的选择

由于煤矿机械所处的环境比较恶劣,因此其设计与制造一般只考虑本身的性能和使用寿命。结合煤矿机械产品的特点,从绿色角度探讨了煤机零件加工工艺过程模型,建立了绿色工艺评价体系,并对带式输送机中滚筒的加工工艺进行了分析,指出了今后煤机产品绿色制造的发展趋势。     

Silicon in intericosahedra chains of boron carbide

Interaction between boron carbide and silicon was studied at 1400–1700 ℃ in a vacuum. The results at 1400 ℃ suggest that silicon substitutes a single atom of carbon per formula unit B₁₂C₃, producing a phase with increased lattice parameters. Temperature increase improves the degree of transformation, but at 1700 ℃, the product starts to lose silicon. Analysis of DFT formation energies of configurations with B₁₂C₃ and B₁₂C₂Si stoichiometries shows that B₁₂C₂Si may have two ground states with practically equal stability. The first is B₁₁Si(C-B-C) with silicon in icosahedral polar position, and the second is B₁₂(C^Si^C), where the silicon is in the middle of an angular chain. The latter is suggested to be more favorable during the synthesis, while the former is very close to equilibrium with its precursor B₁₁C(C-B-C), and its formation may be inhibited. Comparison of XRD patterns for the synthesis products and modeled structures seems to confirm this suggestion.     

丙烯酸酯改性水性聚氨酯乳液的合成及胶膜性能研究

以异佛尔酮二异氰酸酯（IPDI）、聚碳酸酯二醇（PCDL）、二羟甲基丙酸（DMPA）三乙胺（TEA）、甲基丙烯酸甲酯（MMA）、丙烯酸丁酯（BA）为原料,采用原位乳液聚合法制备水性聚氨酯-丙烯酸酯（WPUA）复合乳液。考察了聚氨酯（PU ）含量、m(MMA):m(BA)、初始-NCO与-OH物质的量之比等因素对WPUA复合乳液及其胶膜性能的影响。结果显示,当w(PU)质量分数为80%、初始n(-NCO):n(-OH)=6.0、w(DMPA)=5%、m(MMA):m(BA)=4:6时,所得WPUA乳液性能稳定,其胶膜吸水率降低至9.80%,相比较未改性的聚氨酯胶膜的吸水率24.75%,其吸水率降低了60.4%;改性胶膜的拉伸强度达到28.9MPa,是未改性聚氨酯胶膜的1.53倍,制备出了性能稳定、具有优异耐水性和物理机械性能的WPUA复合乳液。     

Cationic microgel emulsion with a high solid content by a multistep addition method in inverse microemulsion polymerization

The multistep addition of a monomer and initiator was developed to successfully synthesize cationic polyacrylamide microgels with solid contents (SCs) greater than 35% and cationic monomer concentrations of 0–40 mol % by inverse microemulsion polymerization. Two feed methods, three‐step nonuniform addition and five‐step uniform addition, were implemented to obtain microgel emulsions with 37% SC. The former addition method was designed according to the solubilization limit of the microemulsion before step polymerization, and that of the latter was a constant based on the remaining surfactant weight in the reactor. The product properties in the intermediate processes of these two methods were compared by dynamic light scattering and viscosity measurement. The results show that the products here were translucent microemulsions instead of milky ones when they were synthesized by a semicontinuous polymerization. Also, the particle sizes of these two methods were almost the same; this indicated that the oscillation phenomenon in continuous polymerization at a high SC was avoided. With the former feed method, the risk and operation cost in the synthesis process could be cut down greatly. Moreover, the viscosity of the cationic microgel emulsion conformed to the Krieger–Dougherty equation with a greater value of intrinsic viscosity than that of a hard‐sphere system because of an electroviscous effect. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40585.     

4A分子筛合成研究

本实验主要以化学原料、高岭土和凹凸棒石粘土为原料,通过酸化,碱化,成胶,晶化这一工艺过程,利用传统水热法成功合成了4A分子筛,并通过微波法进行对比。实验过程使用光学显徽镜进行观察;产品通过X射线粉末衍射、NEXUS670型傅里叶红外光谱仪进行了表征。结果表明,传统水热法与微波法均能合成出4A分子筛,并且微波法合成出的样品粒度小且均匀,合成时间大幅减少,降低了能耗。