Photocatalytic TiO2 films deposited by reactive magnetron sputtering with unipolar pulsing and plasma emission control systems

TiO₂ films with thickness of about 500 nm were deposited on unheated non-alkali glass substrates by reactive magnetron sputtering using one Ti metal target with unipolar pulsed powering of 50 kHz and the plasma emission feedback system (PCU). In order to keep the very high deposition rate, the depositions were carried out in the “transition region” between the metallic and the reactive (oxide) sputter mode where the target surface was metallic and oxidized, respectively. Stable deposition was successfully carried out in the whole “transition region” with PCU at total gas pressure of 3.0 Pa. All the as-deposited films deposited in the “transition region” showed amorphous structure, which performed very low photocatalytic activity. After the post-annealing in air at higher than 300 °C, all the films crystallized to anatase polycrystalline structure. They performed both photoinduced decomposition of acetaldehyde and photoinduced hydrophilicity under UV light illumination. The highest deposition rate in this study to deposit the photocatalytic TiO₂ films in the “transition region” was 90 nm/min, which was over twenty times higher than that for conventional sputter deposition processes.     

Preparation of SnO2 whiskers via the decomposition of tin oxalate

A new method for preparing SnO₂ whiskers by the decomposition of SnC₂O₄ is suggested. A Whisker-like morphology of a SnC₂O₄ precipitate was attained via the gradual addition of an oxalic acid solution to a hot SnCl₂ aqueous solution (T > 50^∘C). In comparison, when the solution temperature was either lower than 50^∘C or when ethanol was used as the solvent, the SnC₂O₄ precipitate showed an angular and relatively isotropic morphology. The morphology of the SnC₂O₄ precipitate remained even after its thermal decomposition into SnO₂ at 400^∘C indicating that SnC₂O₄ precipitation is a key step in preparing the whiskers. The formation mechanism of SnO₂ whiskers was explained by the supersaturation during the precipitation of SnC₂O₄.     

养禽育雏室的节能改造研究

主要介绍了目前禽舍建筑所存在的能耗问题和环境问题,以及对其进行节能改造的措施。改造的措施包括了禽舍温控区域的限定,围护结构的改造和在屋顶南向坡面加装采光板。对改造方案进行的能耗分析表明了节能的显著效果。     

高温下CN--Ni-Au-H2O体系热力学性质的理论研究

为了克服现有治理工业含氰废水方法存在的不足,对已经成功完成了小试试验的活性炭催化电解氧化法的热力学行为进行了分析.通过分析计算,证明在高温条件下工业含氰(CN--Ni-Au-H2O体系)废水能够被电解,常温下更适合工业化操作.     

一种环保化学储能电池——钒氧化还原液流电池

可再生能源需要性能优良的储能电池与之配套，因此，研究和开发价廉、高效率的储能系统是十分必要的。本文通过介绍钒氧化还原液流电池的原理和特点，指出钒电池是一种潜力巨大的新型环保储能电池。同时介绍钒电池制备和应用时的三大技术关键及一定的解决方法。     

植物光诱导延迟发光介导的酸性环境污染监测

酸雨和大气污染会对植物叶片内叶绿体的结构和功能产生影响，而植物光诱导延迟发光（DLE）被认为主要产生于叶绿体的PSⅡ中。利用自制的弱光探测系统，以生长周期长、叶片面积大的紫荆花叶片作为实验材料，研究了模拟酸雨和SO2对其DLE特性的影响。结果发现，绿色植物叶片光诱导DLE强度的变化能很好地反映植物叶片中叶绿体完整性以及叶绿体功能的变化。凶此，可以用DLE强度的变化来表征环境对植物的胁迫程度，有望为环境污染监测及生物学评价提供新的手段。     

Structural and electronic properties of zirconia phases: A FP-LAPW investigations

The structural and electronic properties of ZrO₂ polymorphs were investigated using density functional theory (DFT). The Kohn–Sham equations were solved by applying the full-potential linearized augmented plane wave (FP-LAPW) method. We used the generalized gradient approximation (GGA) in the Perdew–Wang formalism to the exchange and correlation energy functional. The ground state properties such as lattice parameter, transition pressures, bulk modulus and its pressure derivative as well as the structural phase stability were calculated. The results were compared with previous calculations and experimental data when available. The FP-LAPW method correctly orders the zero temperature energies of all zirconia polymorphs. We have also studied the effect of distortion from the cubic to the tetragonal structure on the basis of charge density calculations. On the other hand, band structure and density of states (DOS), which allow us to discuss the features of orbital mixing, are also given. Our results suggest that the cotunnite structure should be better than the other zirconia phases as gate dielectric material.     

Modeling growth rate of HfO2 thin films grown by metal-organic molecular beam epitaxy

HfO₂ dielectric layers were grown on the p-type Si (100) substrate by metal-organic molecular beam epitaxy (MOMBE). Hafnium-tetra-butoxide, Hf(O·t-C₄H₉)₄ was used as a Hf precursor and Argon gas was used as a carrier gas. The thickness of the HfO₂ film and intermediate SiO₂ layer were measured by scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). The properties of the HfO₂ layers were evaluated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), high frequency (HF) capacitance-voltage (C-V) measurement, and current-voltage (I-V) measurement. C-V and I-V measurements have shown that HfO₂ layer grown by MOMBE has a high dielectric constant (k) of 20-22 and a low-level of leakage current density. The growth rate is affected by various process variables such as substrate temperature, bubbler temperature, Ar and O₂ gas flows and growth time. Since the ratio of O₂ and Ar gas flows are closely correlated, the effect of variations in O₂/Ar flow ratio on growth rate is also investigated using statistical modeling methodology.     

基于J2EE和J2ME的安全移动电子银行

基于J2ME和J2EE，结合AES算法设计一个移动电子银行安全技术方案，通过移动用户与银行服务器之间的数据加密、身份认讧和数据完整性实现端对端数据安全技术．在支持Java MIDP技术的设备中进行实验，表明该方案可以取得良好的效果．     

SUP>228/SUP>Ra-SUP>228

研究了以钍为原料制备228Ra-228Ac发生器的方法。在2 mol/L HNO3的Th(NO3)4溶液中,先用50%TBP/CCl4萃取剂,通过两次错流萃取,除去约75%的钍,再用30%TRPO/煤油两次萃取,钍的去污因子大于105,在这个过程中,Ra的回收率大于99%。用自制的-αMnO2研究了酸性条件下MnO2对水溶液中Ra和钍系核素的静态吸附及对Ra,Ac的动态吸附。研究结果表明,在室温下,二氧化锰对Ra,Ac的吸附分配系数Kd随酸度的升高而下降,除Pb外,对钍及钍系其它核素不吸附。选择在0.2 mol/L HNO3介质中吸附时,Ra-Ac的分离效果最好,分离因子接近104。用0.2 mol/L HNO3解吸吸附柱上Ra衰变的Ac可得到很纯的228Ac溶液。给出了制备228Ra2-28Ac发生器的工艺流程。