Synthesis of GaN Nanorods by Ammoniating Ga2O3/ZnO Films

Large quantities of CaN nanorods are successfully synthesized on Si（111） substrates by ammoniating the films of Ga2O3/ZnO at 950℃ in a quartz tube. The structure, morphology and optical properties of the as-prepared CaN nanorods are studied by x-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, Fourier transform infrared spectroscopy, and photoluminescence. The results show that the CaN nanorods have a hexagonal wurtzite structure with lengths of several micrometres and diameters from 80 nm to 300hm, which could supply an attractive potential to harmonically incorporate future GaN optoelectronic devices into Si-based large-scale integrated circuits. The growth mechanism is also briefly discussed.     

自制T型石英管氢化物原子吸收法测定水中汞

汞是环境中重要的有毒元素。简单、快速、准确地测定其含量,对保障人类免受其毒害有重要作用。目前,测定汞主要用测汞仪,有些产品性能很不稳定,原子吸收测汞也有探讨。本文用自制T形石英管测定水中汞,结果表明,该法样品用量少、灵敏、精密度高,检出限低,有结构简单、成本低、使用方便等优点。 1 试验部分 1.1 主要仪器与试剂 WFX-1F型原子吸收分光光度计(北京第二光学仪器厂) HG-25型氢化物发生器(北京高智技术研究所) 仪器工作条件:波长-253.7nm,光谱通带宽度-0.2nm,原子化温度-室温,载气流量-200ml·min~(-1)。 纯水:电导率0.5μs·cm~(-1)(北京化工厂) 汞标准液及应用液:氯化汞(GR)配制 其余试剂均为AR级 载气:高纯氩 T型石英管规格(见图)     

原子吸收光谱法测定气样中一氧化碳的研究

本文研究了用自制Ｎｉ（ＣＯ）４发生管和电加热石英管原子化器间接测定一氧化碳的条件，探讨了Ｎｉ（ＣＯ）４的产生和在石英管中原子化效率及干扰消除。     

火焰原子吸收法测定大豆、茶叶及合金中微量铁和锰

本文用ＦＡＡＳ法对大豆、茶叶及合金中的铁和锰进行研究［１－４］。根据实验结果，铁的变异系数为１．０～３．７％，回收率为９８～１０１％；锰的变异系数为２．４～３．５％，回收率９７～１０３％，均得到较为满意的结果，具有较好的实用价值。     

单缝石英管火焰原子吸收法测定蒜头、茶叶、大米中微量硒

本法利用单缝石英管，提高火焰原子吸收法的灵敏度并降低测试成本。方法用于大米、蒜头、茶叶中硒的测定，获得满意的结果。     

Dielectrophoretic assembly of ZnO nanowires

The synthesis of zinc oxide （ZnO） nanowires is achieved by vapor phase transportation （VPT） method. The designed quartz tube, whose both ends are narrow and the middle is wider, is used to control the growth of ZnO nanowires. Dielectrophoresis （DEP） method is employed to align and manipulate ZnO nanowires which are ultrasonic dispersed and suspended in ethanol solution. Under the dielectrophoretic force, the nanowires are trapped on the pre-patterned electrodes, and further aligned along the electric field and bridge the electrode gap. The dependence of the alignment yield on the applied voltage and frequency is investigated.     

激光透射成像法测量石英管的外径与壁厚

为了同时同位测量石英管的外径和壁厚,建立了激光透射成像系统,对系统测量原理进行研究。基于几何光学和菲涅尔公式,分别导出平行光垂直照射石英管后的透射光线偏向角、相对光强与入射光线离轴距离之间的关系;通过数值计算,分析了偏向角、相对透射光强随入射光线离轴距离的变化特点;针对物方远心光路,分析了光阑对偏向角和相对光强的限制;基于CCD成像原理,通过引入标定系数和补偿因子,导出石英管外径与壁厚的计算公式。实验结果表明:外径绝对误差和相对误差的平均值分别为0.119mm和0.91%,壁厚绝对误差和相对误差的平均值分别为0.153mm和6%。     

宏观尺寸弯曲石英管对中低能电子束的导向作用

研究了宏观尺寸的弯曲圆柱形石英管对 1 100, 1 300和1 500 eV 3种能量电子束的导向作用, 并对实验结果与相同材质和尺寸的直管的情形进行了分析对比。 实验中利用一个位置灵敏法拉第筒对从石英管出射的电子束进行探测, 获得从管道中出射的电子束流强度在位置灵敏法拉第筒各道上的分布, 其结果显示宏观尺寸石英管对电子束存在导向作用。 与慢速高电荷态离子和绝缘毛细管相互作用的物理过程类似, 这种导向效应是由电荷在管壁内表面自组织充电引起的。 实验还发现, 入射电子束流的强度越强, 其导向作用越明显, 这与微观尺寸毛细管对慢速高电荷态离子的导向作用不同。 石英管导向能力与管的尺寸、 形状及材料之间的关系还有待进一步的系统研究。 It was inevstigated in the experiment that the guiding effect of electron beam with energy of 1 100, 1 300 and 1 500 eV through a bended cylindrical quartz tube with macro sized. A position sensitive Faraday cup was developed and used to detect the electron beam transmitted through the quartz tube, and the distribution of transmitted beam current on each channel of the Faraday cup was acquired. Results indicate the existence of guiding effect which is due to the self organized charge up in the inner wall of the quartz tube similar to that of the highly charged ions. We also found that the guiding ability of the tube is related to the incident beam intensity. The relationship between the guiding ability and the material as well as the size of the tube is to be studied in the near future.     

流动注射石英管原子吸收法测定微量总汞

建立了一套流动注射石英管原子吸收光谱法测定土壤、植物和药品等样品中微量Hg的方法，研究了酸度、载液和还原液流速及其浓度、氩气流量等条件对测定结果的影响。采用五氧化二钒、硝酸、硫酸进行消解，可获得可靠的分析结果。方法特征量为59pg，检出限为0.028μg/L；相对标准偏差为1.60%-3.86%；回收率为94％－102％。     

长缝石英管氢化物-火焰原子吸收光谱法测定化探样品及铅锭中微量锡

长缝石英管氢化物原子吸收法测定锡,具有较低的检出限,是一个方便、快速、灵敏的分析方法,特别适用于地质化探样品及铅锭的测定.通过对锡氢化物发生的酸度等条件进行了研究并提出克服干扰元素的办法.地质样品测定下限为0.5×10~(-6)g,铅锭样品测定下限为0.075×10~(-6)g.完全满足地质化探及铅锭测定的技术要求.