乙酸盐上二氧化碳和二醇合成环状碳酸酯

在乙腈体系中,以不同的乙酸盐作催化剂,研究了CO2与二醇合成环状碳酸酯的反应.乙腈在反应过程中不仅是溶剂,而且还起到了脱水剂的作用,促进了反应的进行.以1,2-丙二醇为反应物对催化剂进行筛选,发现无水乙酸锌具有最高的催化活性.在无水乙酸锌上考察了二氧化碳和不同二醇的反应,结果表明,五元环碳酸酯的产率明显高于六元环碳酸酯,其中碳酸丙烯酯的产率最高.以1,2-丙二醇为反应基质,无水乙酸锌为催化剂,确定了最佳反应条件,1,2-丙二醇100 mmol,乙睛10 mL,催化剂2.5 mmol,反应压力10 MPa,温度170 ℃,反应12 h.在此条件下,碳酸丙烯酯的产率达到了24.2%,1,2-丙二醇的转化率为38.9%.     

氧化钙室温催化碳酸丙烯酯和甲醇的酯交换合成碳酸二甲酯

 在室温条件下用氧化钙催化碳酸丙烯酯（PC）和甲醇的酯交换反应，高收率、高选择性地合成了碳酸二甲酯（DMC）．在假设羟丙基甲基碳酸酯（HPMC）是反应中间产物的基础上，计算了甲醇、PC和HPMC的电荷分布，并推论出可能的副反应PC的聚合．通过考察反应温度对DMC选择性和收率的影响，证明了关于中间体HPMC和副反应PC聚合的假设．考察了加料顺序、反应温度对DMC生成速率的影响，并在此基础上提出了氧化钙催化PC和甲醇酯交换合成DMC的可能机理．     

载体表面性质对Cu/ZrO2催化剂CO加氢反应行为的影响

用XRD、LRS、NH₃-TPD、CO₂-TPD和CO-FTIR等表征手段考察了不同温度焙烧的氧化锆表面性质的差别,特别是表面酸碱性的差异对Cu/ZrO₂催化剂CO加氢反应行为的影响。结果表明,不同温度焙烧的氧化锆表面酸碱性具有较大的差异,其中以450℃焙烧的氧化锆具有较高的表面碱性和最低酸性。这些表面性质的差异对于Cu/ZrO₂催化剂的CO吸附行为产生较大的影响,进而影响CO的加氢反应活性。以450℃焙烧的氧化锆为载体时,Cu/ZrO₂催化剂具有较好的反应活性。     

超临界相中的长链烷烃催化脱氢

The preparation of olefins from long chain alkanes by catalytic dehydrogenation is an important process in synthetic detergents and surface-active agents[1]. Because of equilibrium limitation, the present process only reaches about 10 % of the conversion with 90 % of the selectivity. In addition, the lifetime of the catalysts ( e. g. Pt-Sn/Al2O3) is around 40 d owing to the severe coke formation even with n(H2 )/n(alkane)= 8. Although the catalysts have been well improved, both conversion and selectivity were hardly enhanced. New technique is therefore required to improve the process.     

CO2/H2在不同形态ZrO2上的吸附行为

利用傅立叶变换红外光谱技术(FT-IR)考察了CO2和CO2＋H2在不同形态氧化锆上的吸附和转化行为，结果表明,氧化锆的形态影响CO2的吸附形式和表面物种的生成.无定型氧化锆上主要生成碳酸氢盐和离子碳酸盐，单斜氧化锆上还出现了双齿碳酸盐，而在四方氧化锆上出现最强的线式吸附CO2，并生成聚碳酸盐.在氢气存在的条件下，单斜氧化锆上生成甲烷而在四方氧化锆上则生成甲酸盐.     

Synthesis of C_2 oxygenated compounds from syngas in supercritical cyclohexane

Catalytic synthesis of C2 oxygenated compounds from syngas in supercritical cyclohexane was reported in this paper. The effect of the molar ratio of media to feed on the conversion and selectivity was mainly discussed. The results showed that the selectivity of C2 oxygenated compounds in supercritical cyclohexane was greatly improved, and the by-products of acetic acid, ace tic ester and alkanes were efficiently suppressed. Although the CO conversion was slightly declined, the space-time yield of C2 oxygenated compounds basically kept the constant at high media/feed ratio.     

利用可变形镜进行像差校正研究

利用可变形镜对光学系统某一视场角像差进行单独动态校正.系统中使用可变形镜将全视场内某一特定视场角的像差校正到衍射极限水平,该区域在整个视场内动态高速地改变来对视场内任意区域进行高分辨率成像.利用这种技术可实现光学系统的小型化、轻型化,减小系统的体积,同时由于实现变分辨率成像,数据量大大减少,降低了数据传输对带宽的要求.     

ZnⅪⅩ离子3d^2—3p^3d跃迁的多组态相对论理论计算

用多组态相对论理论对ZnⅪⅩ(离子3s^2，3s^3p，3p^2，3s3d，3p3d，3d^2，3s4s，3s4p，3s4f组态能级结构进行了计算与分析。在已有实验工作的基础上，运用参数拟合方法计算了ZnⅪⅩ(离子上述组态能级，获得了能级结构参数的最佳计算值。由这些参数值进一步预测计算了ZnⅪⅩ离子n=3Complex中3d^2-3p3d组态能级跃迁的谱线波长，振子强度和跃迁概率。     

Microwave photonic filter design and optimization based on stimulated Brillouin scattering using a directly modulated pump

We propose a general guideline on the design of a stimulated Brillouin scattering(SBS)-based microwave photonic filter(MPF) using a directly modulated pump. Filter gain profiles and passband ripples with waveform repetition periods of the driving current ranging from 2 to 100 ns are measured after the transmission of different fiber lengths. The results show that the filter performance has nothing to do with the fiber length, and the digitalto-analog converter bandwidth requirement for the driving current is no more than 500 MHz. Therefore, the low cost, flexible reconfiguration, and miniaturization characteristics make an SBS filter using a directly modulated pump a promising choice as an MPF.     

利用可变形镜进行像差校正研究

利用可变形镜对光学系统某一视场角像差进行单独动态校正．系统中使用可变形镜将全视场内某一特定视场角的像差校正到衍射极限水平,该区域在整个视场内动态高速地改变来对视场内任意区域进行高分辨率成像．利用这种技术可实现光学系统的小型化、轻型化,减小系统的体积,同时由于实现变分辨率成像,数据量大大减少,降低了数据传输对带宽的要求．