CO_2激光器用的气体发生器

我们在研制气体转换炉工作[1]的基础上,经过改进又制成气体发生器.将它分别用于波导 CO2激光器和 TEA CO2激光器,所得的结果表明,对于采取气体流动方式工作或需要更换工作气体的CO2激光器,如果配备一台气体发生器,就可以由空气,CO2,空气 CO2,N2 CO2等获得多种组分的工作气体     

蛋氨酸合酶催化反应研究Ⅵ.3-N-取代-6-甲基尿嘧啶的合成

首次报道了以苄氧羰氧次甲基作为6-甲基尿嘧啶环上N1位的保护基.选择性的在尿嘧啶环上N1保护、N3取代及N1脱保护等反应都在简便、高收率条件下进行,经四步反应高选择性地合成了3-N-取代-6-甲基尿嘧啶.     

激光分子束外延氧化物薄膜机理研究

实验结果表明外延结构复杂的氧化物薄膜,基片温度在600～650℃条件下,其表面原胞层的扩散时间是几十秒到上百秒.根据此特点,采用单原胞间歇式外延,用激光分子束外延制备原子尺度控制的高质量氧化物薄膜和超晶格材料.     

Investigation the positive moments on the M－T curve of YBCO films measured by using zero-field cooling

The superconducting transition of a YBCO film was measured by a MPMS-5 superconducting quantum interference device magnetometer, using a zero-field cooling process. The experimental results have shown that there are positive magnetic moment and positive peak on the M－T curve. We have proven that these anomalous behaviours are due to measurement error, but not phase transition. We have proposed a simple formula to explain and to calculate quantitatively these anomalous behaviours. It was found that, provided dH>0.59H_p (dH is the inhomogeneous field of the remnant field, H_p is the fully penetrated field of the measured sample), the experimental results will be positive, not negative. If dH≥2H_p, the experimental results will be symmetrical to their real negative values. From the M－T curve, which has positive moment and positive peak below T_c (superconducting transition temperature), we found a new possible method to obtain H_p of the measured sample.     

空间与频率双性能的薄膜光学滤波器

通过耦合两个掺杂的一维光子晶体，提出了同时兼具频率和空间光学滤波双性能的一维光子晶体异质结结构.在一个宽的频带范围内, 该结构只允许法向入射的确定的一种中心频率光透过，偏离法向此中心频率光全反射; 而在这宽频带范围内其他频率所有的光在任何角方向都全反射. 关键词： 一维光子晶体 光学滤波器 光学薄膜 光通信     

用激光分子束外延在Si衬底上外延生长高质量的TiN薄膜

采用激光分子束外延技术,利用两步法,在Si单晶衬底上成功地外延生长出TiN薄膜材料.原子力显微镜分析结果显示, TiN薄膜材料表面光滑,在10 μm×10 μm范围内,均方根粗糙度为0842nm.霍耳效应测量结果显示,TiN薄膜在室温条件下的电阻率为36×10^-5Ω·cm,迁移率达到5830 cm²/V·S,表明TiN薄膜材料是一种优良的电极材料.X射线θ—2θ扫描结果和很高的迁移率均表明,高质量的TiN薄膜材料被外延在Si衬底 关键词： 激光分子束外延 TiN单晶薄膜 外延生长     

EXPERIMENTAL STUDY OF DIFFRACTIVE PROPERTIES OF WAVELENGTH-SIZED SINGLE GROOVE IN Si-Si3N4 SUBSTRATE

Experimental results are presented for the diffractive properties of wavelength-sized single groove in Si-Si₃N₄ substrate. The experimental results show that the diffraction of wavelength-sized single grooves in a non-perfectly conducting material is more complex than that of perfectly conducting material. The diffraction intensities change with the change of polarization angle of the incident light. The diffraction intensities for TM polarization light are larger as the groove width is larger. The diffraction intensities of TM polarization light decrease gradually and that of TE polarization light increase gradually when the groove width is close to the wavelength of the incident light. The variations of diffraction intensities are quite different not only for various grooves with different widths but also for different diffraction angles for the same groove. Although the intensity variation of each diffraction order has a very regular sinusoidal dependence on the polarization angles of the incident light, the variation phase of each diffraction order is not all the same.     

PEDOT:PSS Schottky contacts on annealed ZnO films

Polycrystalline ZnO and ITO films on SiO₂ substrates are prepared by radio frequency (RF) reactive magnetron sputtering. Schottky contacts are fabricated on ZnO films by spin coating with a high conducting polymer, poly(3, 4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) as the metal electrodes. The current-voltage measurements for samples on unannealed ZnO films exhibit rectifying behaviours with a barrier height of 0.72 eV (n=1.93). The current for the sample is improved by two orders of magnitude at 1 V after annealing ZnO film at 850 ℃, whose barrier height is 0.75 eV with an ideality factor of 1.12. X-ray diffraction, atomic force microscopy and scanning electron microscopy are used to study the properties of the PEDOT:PSS/ZnO/ITO/SiO₂. The results are useful for applications such as metal-semiconductor field-effect transistors and UV photodetectors.     

A colloidal crystal double-heterostructure fabricated with the angle controlled inclined deposition method

A self-assembly method, named the angle controlled inclined deposition method, is developed for fabricating well-ordered silica and polystyrene colloidal crystals. A high-quality colloidal crystal with a flat and uniform surface over a large area can be produced rapidly using a minute quantity of suspension and without any additional equipment. By controlling the inclined angle, we can fabricate colloidal crystals with diverse numbers of layers. A colloidal crystal double-heterostructure (composed of three different colloidal photonic crystals) can be rapidly fabricated with this method. Both experimental and simulation results show that the photonic band gap of the double-heterostructure is not a simple superposition of that of the compositional colloidal crystals along the stacking direction.     

GaAs/Ga1-xAlxAs半导体量子阱光辐射-热离子制冷

采用数值计算方法分析了GaAs/Ga_1-xAl_xAs 半导体量子阱的光 辐射-热离子制冷. 以漂移-扩散模型为基础，通过电流连续性方程和泊松方程自洽地计算出在外加正向偏压的 条件下半导体内部的载流子分布情况，并在此基础上计算了阱内载流子的发光复合和俄歇复 合，从而确定了半导体异质结量子阱光辐射-热离子制冷的最优条件.进一步分析了不同Al组 分的Ga_1-xAl_xAs材料以及不同的掺杂浓度对制冷效果的影响， 为该领域的实验工作提供了极有价值的参考. 关键词： 半导体异质结 光辐射 制冷