Photoluminescence from Ge-SiO2 thin films and its mechanism

Ge-SiO₂ thin films were deposited on p-type Si substrates using the radio frequency (rf) magnetron sputtering technique with a Ge-SiO₂ composite target. Films were annealed in N₂ ambience for 30 min at 300℃—1000℃ with an interval of 100℃. Through the X-ray diffraction, the average size of Ge nanocrystals (nc-Ge) was determined. They increased from 3.9 to 6.1 nm with increasing annealing temperature in the range of 600℃—1000℃. Under ultraviolet excitation, all samples emit a strong violet band centered at 396 nm. With the formation of nc-Ge, the samples exhibit another emission of orange band with the peak at 580 nm and its intensity increases with the increasing size of nc-Ge. The peak positions of two bands do not shift obviously. Experimental data indicate that the violet band comes from GeO defect and the orange band originates mainly from the luminescence centers at the interface between the nc-Ge and SiO₂ matrix.     

催化反应精馏研究中的若干问题——(I)过程的主要影响因素和操作工艺

主要阐述并讨论了催化反应精馏（ 又称反应或催化精馏） 过程涉及的若干问题．如：化学平衡对相平衡的影响，化学平衡和相平衡的交互作用及进料对操作工艺的影响，塔内催化剂装填方式对过程的影响等     

农村低压电网线损现状及降损措施探讨

本文通过对目前农村低压电网存在的几种线损问题的分析,提出了几种降低线损的措施,可供农村低压电网设计和改造参考.     

CDMA调制解调器的设计

在无线局域网中,引入CDMA技术,即可实现点对点、点对多点的高速计算机通信,它解决了有线网耗资大、携带不便的缺陷。文中提出了一种CDMA调制解调器射频电路和数字基带处理电路框图,分析了它们的组成及工作过程,设计了扩展功能用的系统连接器。由此组装的电路,通过使用CDMA个人身份卡———UIM卡,实现了无线上网、语音通信、收发短消息等功能。     

Inhibition of DNA restrictive endonucleases and Taq DNA polymerase by trimalonic acid C60

Activities of trimalonic acid fullerene (TMA C_60) on DNA restrictive enzymatic reaction were investigated by using two restrictive endonucleases Hind III and EcoR I and plasmid pEGFP-N1 with single restric-tive site for both enzymes. Meanwhile, TMA C60 was also tested to clarify its effects on polymerase chain reaction (PCR) with the catalyst of Taq DNA polymerase and the template of plasmid pEGFP-N1. The products from restrictive reactions or PCR were detected by agarose gel electrophoresis. It was found that the product amounts from restrictive reactions or PCR decreased significantly with addition of TMA C60. The inhibition by TMA C60 was dose-dependent and IC50 values for reactions of Hind III, EcoR I and PCR were 16.3, 6.0 and 6.0 μmol/L, respectively. Addition of two scavengers of reactive oxygen species (ROS), L-ascorbic acid-2-phosphate ester magnesium and sodium azide at the con-centrations of 2―10 mmol/L did not antagonize the activities of TMA C60 against PCR and two restrictive reactions. However, increase of Taq DNA polymerase amounts in PCR system antagonized the activities of TMA C60. These data implied that TMA C60 was able to inhibit the activities of the three above-mentioned enzymes involved in DNA metabolism, and that this inhibition probably did not correlate to ROS.     

低压电气系统无功功率补偿的可行性分析

分析了低压电气系统无功功率产生的原因以及带来的危害和损失,重点介绍了根据实际情况降低无功损耗的方法,以及采取补偿措施后所产生的经济效益。     

基片温度对CNx薄膜性能和结构的影响

采用离子束溅法，在单晶Si（100）基片上制备CNx薄膜。研究了基片温度对CNx薄膜性能和结构的影响。结果表明：随着基片温度的提高，薄膜生长致密，表面光滑；薄膜硬度逐渐提高，但温度升高到200℃后，硬度增加缓慢。同时，基片温度升高使薄膜中的N含量增加，促进C－N化合物结晶。X射线衍射结果证明在850℃时，薄膜中产生α－C3N4晶相。     

辉光放电阴极溅射,瞬变原子化／原子吸收光谱分析性能的研究（Ⅱ）

通过一些元素的测定，进一步研究了辉光放电阴极溅射、瞬变原子化／原子吸收光谱分析技术的如下分析性能：不同Ａｒ气压力下放电电流与放电电压的关系；放电电流、放电功率分别与吸光度的关系；石墨阴极空穴溅射时间对元素分析灵敏度的影响；分析校正曲线的线性范围：基体干扰等。试验表明；增加放电功率是提高分析灵敏度的关键；采用峰面积吸光度方式将大大扩展一些元素分析校正曲线的线性范围。     

Association Mechanism Between Propionic Acid and Trioctylamine

IntroductionIn recent years,solvent extraction has receivedmore and more attention for recovery of carboxylicacids from dilute aqueous solutions,especiallywith the hydrophobic tertiary amines dissolved invarious organic diluents[18] . Studies on theextrac…     

Removing Cr(Ⅵ) from Wastewater by Reactive Extraction

IntroductionIndustrial wastewater containing heavy metal ionsis a main polluting source.Efficient removal andrecovery of toxic heavy metals from industrialwaste streams prior to discharge are of greatsignificance for the environment.Not only does itelimin…