Structure, optical and electrical properties of ZnO thin films on the flexible substrate by cathodic vacuum arc technology with different arc currents

ZnO thin ?lms were successfully deposited onto PET substrates prepared by using cathodic arc plasma deposition (CAPD) technique at a low temperature (<75 °C). Their structure, optical and electrical properties were investigated with various arc currents (40, 45, 50 and 55 A). ZnO (0 0 2) peak was clearly observed, and increased as the arc current increased from 40 A to 55 A. The calculated average crystallized sizes were around 15.9-17.7 nm. The films have an average transmittance over 85% in the visible region, and calculated values of the band gap around 3.33-3.31 eV with increase of the arc current. It was also found that a slight blue shift of optical transmission spectra was observable when decreasing the arc current. The deposited ZnO films had the lowest resistivity; about 3 × 10⁻³ Ω cm for the ZnO ?lm with the arc current of 40 A.     

溶胶-凝胶法制备PTFE/SiO2杂化材料的工艺研究

研究了溶胶-凝胶法制备聚四氟乙烯/二氧化硅(PTFE/SiO2)杂化材料的工艺条件,讨论了乙醇对杂化材料中PTFE与SiO2分散性的影响。按照SiO2在杂化材料粉体中理论含量为50 %的配方来制备PTFE/SiO2杂化材料,分别研究了陈化时间和陈化温度对SiO2实际含量的影响。结果表明,SiO2的含量随陈化时间的延长而增加,在最初的5 h内增长很快,当陈化时间达到48 h后,SiO2含量达到38.9 %。在不同温度下将PTFE/SiO2凝胶陈化1 h,随着陈化温度的升高,SiO2含量出现先增大后减小的趋势,在40 ℃时含量达到最大为19.8 %。     

边界层对三氯氢硅-氢气系统中多晶硅化学气相沉积的影响

This paper presents the numerical investigation of the effects of momentum, thermal and species boundary layers on the characteristics of polycrystalline silicon deposition by comparing the deposition rates in three chemical vapor deposition (CVD) reactors. A two-dimensional model for the gas flow, heat transfer, and mass transfer was coupled to the gas-phase reaction and surface reaction mechanism for the deposition of polycrystalline silicon from trichlorosilane (TCS)-hydrogen system. The model was verified by comparing the simulated growth rate with the experimental and numerical data in the open literature. Computed results in the reactors indicate that the deposition characteristics are closely related to the momentum, thermal and mass boundary layer thickness. To yield higher deposition rate, there should be higher concentration of TCS gas on the substrate, and there should also be thinner boundary layer of HCl gas so that HCl gas could be pushed away from the surface of the substrate immediately.     

硝酸钾结晶器蒸汽喷射增压器的设计与CFD分析

结合硝酸钾冷却结晶实际生产的各项参数,通过严格的理论计算,设计出与生产相匹配的蒸汽喷射增压器,以提高蒸发器的产能和运转周期,降低能耗。并采用流体动力学计算软件Fluent对硝酸钾冷却结晶的蒸汽喷射增压器的工作过程进行数值模拟。比较分析了不同的X（喷嘴出口到吸收室入口的距离）值对流场的影响。结果表明,在一定的工况参数下,蒸汽喷射增压器的流场与X值有着密切的联系。通过数值模拟计算得到,当X=0.01 m时,设计的增压器有效降低了激波引起总压的耗损和减小喷射气流速度的突变,同时在实际生产中得到了良好的应用。      

Efficient La–Ba–MgO Supported Ru Catalysts for Ammonia Synthesis

Abstract  

Novel Ru-based catalysts were prepared by impregnating 2 wt% Ru₃(CO)₁₂ into rare earth (La, Sm, Ce) and barium doped nano-magnesia (RE–Ba–MgO) supports, which were originally prepared by chemical co-precipitation with ultrasonic treatment. The Ru/RE–Ba–MgO catalyst exhibits higher activity, more than three times of that of conventional Ba–Ru/MgO base on water impregnation. Characterization of this catalyst by various techniques reveals that the chemical and textural properties of nano Ba–MgO supports and formation state of barium in support are key factors responsible for the elevated activity of this catalyst.     

1-氨基环丙烷-1-羧酸的合成工艺研究与优化

以氰乙酸乙酯和1,2-二溴乙烷为起始原料,经环烷化、氰基水解、霍夫曼降解合成得到1-氨基环丙烷-1-羧酸。分两步对该合成工艺进行了研究:第一步考察了环烷化反应的主要影响因素,包括1,2-二溴乙烷、碳酸钾、催化剂、溶剂、反应温度、反应时间;第二步考察了氰基水解反应和霍夫曼降解反应的主要影响因素,包括H2O2的用量、NaOH的浓度、霍夫曼降解的反应温度。在考察各个影响因素的同时,得出了较优的工艺条件。经核磁共振和红外光谱分析,所得产品确为1-氨基环丙烷-1-羧酸。实验结果表明,在优化后的工艺条件下,1-氨基环丙烷-1-羧酸的总收率可以达到67.5%。经高效液相色谱分析,产品的纯度为94.4%。     

UV 法测定异噻唑啉酮衍生物活性物含量

采用紫外分光光度法测定了异噻唑啉酮衍生物活性物含量及其氯比,结果表明:在273.0 nm波长下检测,线性范围为0～30.00 mg/L,方法检出限为0.012 mg/L,实际样品的加标回收率为98.9%～101.3%,RSD为0.50%～2.36%;氯比为2.6～3.4时,其半定量的最大吸收波长λmax为272.4～2...     

地铁车站冷水机组应用臭氧冷却水处理技术的性能测试与分析

该文主要介绍在地铁车站的大型集中式空调系统中应用臭氧技术对冷水机组冷却水系统进行处理的实际效果,通过长期的测试数据分析,讨论了冷水机组的实际性能变化情况及影响因素.针对地铁站空调运行期长、气象环境变化跨度大,所造成的冷水机组实际工况多变不定、难以直接衡量其性能变化等问题,采取以实际性能系数与该工况下理想换算性能系数之间...     

N-羧乙基壳聚糖对重金属汞离子絮凝效果的研究

N-羧乙基壳聚糖(NCECS)分子结构中既有氨基又有羧基,是一种两性的壳聚糖衍生物,具有生物相容性、生物降解性、无毒性等特点.合成了一种部分取代的NCECS,用傅里叶红外光谱(FTIR)、元素分析仪对其结构及取代度进行了表征,重点研究了NCECS浓度、絮凝时间、pH等因素对重金属Hg2+的去除率的影响,并探讨了NCEC...     

手性铜试剂在羰基化合物加成反应中的应用

介绍了有机铜试剂具有价格低廉、毒性小、配位能力好等的优点,总结了有机铜试剂在不饱和羰基化合物的不对称共轭加成反应中的应用,特别是催化不饱和酯、硫酯、砜、醛和酮等α,β-不饱和羰基化合物的不对称共轭加成反应,提出了手性铜试剂催化不对称共轭加成反应在底物选择上仍然具有一定的局限性,该反应的底物主要集中于酮类化合物,而砜类和...