偶氮氟膦-PI与锆(Ⅳ)的显色反应研究及应用

研究了不对称变色酸偶氮氟膦-PI(5-FPA-PI)与锆(的显色反应及应用。在0.2~1.6 mol/L盐酸介质中,辅助络合剂过氧化氢和乙二醇存在下,锆(与5-FPA-PI形成组成比为1∶4的稳定蓝色络合物,体系最大吸收波长位于670 nm,表观摩尔吸光系数ε为5.9×104L.mol-1.cm-1。25 mL溶液中,锆(量在0~8μg范围内遵守比尔定律,加入掩蔽剂抗坏血酸,体系的选择性理想。方法已用于天然石灰石、地下岩石、不锈钢及铝合金中锆(的测定,加标回收率为96.8%~100.7%。     

用臭氧管和紫外线灯进行消毒除臭的新进展

本文介绍了臭氧发生管和紫外线灯在居室和电冰箱内的消毒除臭方法，也介绍了一些新的消毒除臭方法。     

十二烷基磺酸钠存在下DBC-偶氮氯膦分光光度法测定化学试剂中的痕量铝

研究在pH 4.3 HAc-NaAc缓冲介质中,Al(Ⅲ)一（DBC-偶氮氯膦）一十二烷基磺酸钠( SDS)体系光度性质。研究结果表明：该显色体系的λmax= 622 nm,ε622nm=1.41×104 L·mol-1.cm-1,络合物组成比为Al(Ⅲ)：(DBC-CPA)=1:1,铝量在0.20～1.20 mg.L-1范围内遵守比耳定律。方法已满意地用于碳酸氢钠、氢氧化钠中痕量铝的测定。     

Ozonation of Several Organic Compounds Having Low Molecular Weight under Ultraviolet Irradiation

Ozonation of several low molecular weight organic compounds under ultraviolet irradiation was studied. Nine compounds were identified as reaction products of the ozonation of phenol which was promoted by the simultaneous use of ozone and ultraviolet irradiation. In the case of several organic compounds having carbon numbers from one to six, the removal of total organic carbon (TOC) by this simultaneous use was higher than by either the ozone oxidation method or the ultraviolet irradiation method for all the compounds.     

极紫外光刻真空工件台技术研究

在极紫外光刻系统中,真空工件台的运行精度、速度、加速度以及动态定位和扫描同步性能是影响整机成像质量、套刻精度和产率的重要因素。结合极紫外光刻机的工作原理和发展现状,论述了极紫外光刻机真空工件台系统的特征、组成及其关键技术。     

Lead and cadmium in tissues from horse, sheep, lamb and reindeer in Sweden

 Levels of lead and cadmium were determined in tissues of muscle, liver and kidney from horse, lamb, sheep and reindeer in Sweden during the years 1994–1997. Mean levels of lead in muscle, liver and kidney from horse were <0.002, 0.13 and 0.047, from lamb <0.002, 0.031 and 0.053, from sheep <0.002, not analysed and 0.046, and from reindeer 0.003, 0.13 and 0.13 mg/fresh weight, respectively. The mean levels of cadmium in muscle, liver and kidney from horse were 0.042, 2.5 and 18, from lamb 0.0019, 0.031 and 0.12, from sheep 0.0034, not analysed and 1.0, and from reindeer 0.003, 0.60 and 2.7 mg/fresh weight, respectively. Comparisons with literature data were attempted. In some cases the results could differ by several orders of magnitude. It cannot be ruled out that some of the differences between studies might be due to analytical differences, making comparisons very difficult. Received: 2 June 1998     

Smooth and Vertical Facet Formation for AlGaN-Based Deep-UV Laser Diodes

Using a two-step method of plasma and wet chemical etching, we demonstrate smooth, vertical facets for use in Al _x Ga_1−x N-based deep-ultraviolet laser-diode heterostructures where x = 0 to 0.5. Optimization of plasma-etching conditions included increasing both temperature and radiofrequency (RF) power to achieve a facet angle of 5 deg from vertical. Subsequent etching in AZ400K developer was investigated to reduce the facet surface roughness and improve facet verticality. The resulting combined processes produced improved facet sidewalls with an average angle of 0.7 deg from vertical and less than 2-nm root-mean-square (RMS) roughness, yielding an estimated reflectivity greater than 95% of that of a perfectly smooth and vertical facet.     

用DSPCF分光光度法测定钯

在室温下以硝酸为介质,钯与DSPCF形成有色络合物,其表观摩尔吸光系数ε_(520)=1.2×10~4,络合物组成为Pd(Ⅱ):DSPCF=1:2。其特点是在室温下发生显色反应,当加入HNO_3使介质达1.75N时,只有Pd(Ⅱ)—DSPCF红色络合物不褪色,可用于铂钯二次精矿等的测定。     

Exciton-induced degradation of organic/electrode interfaces in ultraviolet organic photodetectors

We study the degradation mechanisms of ultraviolet (UV) organic photodetectors (OPDs). Contrary to expectations, we determine that the bulk of the organic layers in UV OPDs is stable under prolonged UV irradiation, showing no detectable changes in photophysical characteristics such as photoluminescence yield and exciton lifetime and thus not contributing to the observed degradation behavior of UV OPDs. However, the results show that the organic/electrode interfaces in UV OPDs, including indium tin oxide (ITO)/organic and organic/metal ones, are susceptible to UV irradiation, leading to a deterioration in both charge injection and extraction across the interfaces. The degradation of the organic/electrode interfaces in UV OPDs is essentially induced by UV-generated excitons in their vicinity and may be responsible for nearly 100% of the photo-current loss of UV OPDs. Approaches for improving the photo-stability of organic/electrode interfaces, and thus the lifetime of UV OPDs, are also investigated. We demonstrate that the use of thin (∼0.5 nm) interfacial layers such as lithium acetylacetonate at organic/metal interfaces can significantly reduce the interfacial degradation, and the use of appropriate hole transport materials such as N,N′-bis (naphthalen-1-yl)-N,N′-bis(phenyl) benzidine at ITO/organic interfaces can greatly improve the interfacial photo-stability.     

高性能背照式GaN/AlGaN p-i-n紫外探测器的制备与性能

研究了GaN/AlGaN异质结背照式p-i-n结构可见盲紫外探测器的制备与性能。GaN/AlGaN外延材料采用金属有机化学气相沉积（MOCVD）方法生长，衬底为双面抛光的蓝宝石，缓冲层为AlN，n型层采用厚度为0.8 μm的Si掺杂Al0.3Ga0.7N形成窗口层，i型层为0.18 μm的非故意掺杂的GaN，p型层为0.15 μm的Mg掺杂GaN。采用Cl2、Ar和BCl3感应耦合等离子体刻蚀定义台面，光敏面面积为1.96×10-3 cm2。可见盲紫外探测器展示了窄的紫外响应波段，响应区域为310~365 nm，在360 nm处响应率最大，为0.21 A/W，在考虑表面反射时，内量子效率达到82％；优质因子R0A为2.00×108 Ω·cm2，对应的探测率D*=2.31×1013 cm·Hz1/2·W-1；且零偏压下的暗电流为5.20×10-13 A。