直接观测法塞曼效应实验系统的优化调整

提出了塞曼效应实验仪调整中系统优化的理念,给出了直接观测法塞曼效应实验系统的优化方法.     

大分离条件下风力机叶片三维定常数值模拟研究

为了改善失速条件下风力机气动特性的CFD模拟精度,采用定常的RANS求解方法和一方程S-A湍流模型,数值模拟定桨距型风轮叶片LM19在高风速(18m/s)条件下的气动特性.首先讨论了由流动大尺度分离导致计算收敛曲线大幅度振荡时数值结果的处理方法,然后分析了计算域尺度和网格密度对数值模拟结果的影响,为失速条件下风力机气动...     

空间电荷场对自由电子激光中电子稳态轨道的影响

本文从三维模型出发,详细地研究了自由电子激光中电子束空间电荷场对相对论性电子稳态轨道的影响,发现考虑空间电荷场的三维效应后,电子稳态轨道出现新的不稳定性区域。 关键词：     

Effect of Reactor Pressure on Qualities of GaN Layers Grown by Hydride Vapour Phase Epitaxy

The influence of reactor pressure on GaN layers grown by hydride vapour phase epitaxy （HVPE） is investigated. By decreasing the reactor pressure from0. 7 to 0.5 mm, the GaN layer growth mode changes from the island-like one to the step flow. The improvements in structural and optical properties and surface morphology of GaN layers are observed in the step flow growth mode. The results clearly indicate that the reactor pressure, similarly to the growth temperature, is One of the important parameters to influence the qualities of GaN epilayers grown by HVPE, due to the change of growth mode.     

在高氯酸铕-二苯亚砜-邻菲罗啉三元配合物中Pr3+对Eu3+发光的影响

合成了一系列异核配合物[(Eu1-xPrx)(DPSO)(phen)3(ClO4)2]ClO4*nH2O(x=0.000～0.200, DPSO为二苯亚砜, phen为邻菲罗啉, n=1, 2, 3, 4, 5, 6). 对配合物进行了组成分析, 摩尔电导, IR光谱及荧光激发和发射光谱的测定. 荧光光谱测定结果表明 本身不发光的Pr3+对Eu3+的发光产生较大影响, 当Pr3+的掺入量为0.001 mol时, 可使Eu3+的发光强度提高到200%以上,随着Pr3+浓度的增大,对Eu3+的发光先敏化后猝灭.Eu3+在配合物中所处的格位对称性低,无对称中心.     

ICP-AES测定南方离子型稀土精矿中稀土配分

采用 ICP- AES同时测定了南方离子型稀土精矿中 L a、Ce、Pr、Nd、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb、Lu和 Y组分的含量。选择了合适的分析线 ,确定了各元素的检出限为 0 .0 4— 13.6 μg/L,加标回收率为 90 %— 110 %。方法准确、快速、简便 ,已用于生产实践中     

碳黑颗粒生长模型的初步研究

本文利用反应类(Reaction Class)概念和矩(Moment)方法,研究了层流预混甲烷火焰中碳黑颗粒的成核与长大过程。模型综合考虑了颗粒的成核、颗粒间由于碰撞的聚合、以及气态组分在颗粒表面的生长。通过数值计算预报了碳黑颗粒平均粒径、总表面积、体积分数和数密度,以及萘(A4)和乙炔(C2H2)在颗粒表面的增长速率。     

益母草多糖的抗氧化性

测定益母草多糖含量和研究其多糖的抗氧化性.利用水提醇沉法提取粗多糖,并利用Sevage法脱蛋白对其进行纯化;采用苯酚-硫酸法测定益母草多糖样品中纯多糖的含量并采用邻苯三酚自氧化法和水杨酸法分别研究益母草多糖清除O2-·和·OH的效果.益母草提取所得多糖样品中纯多糖含量达48.5％,益母草多糖具有较强的清除O2-·和·OH的作用.     

Temperature and substrate dependence of structure and growth mechanism of carbon nanofiber

The carbon nanofibers were grown on Ni/Si and Ni/Ti/Si substrates in 1 atm CH₄ atmosphere at 640 °C and 700 °C by thermal chemical vapor deposition method. The carbon nanofibers were characterized by field emission scanning electron microscopy, transmission electron microscopy, and Raman spectrometry for morphology, microstructure, and crystallinity. The electron emission property of carbon nanofibers was also investigated by current-voltage (I-V) measurement. The results showed that the solid amorphous carbon nanofibers could be grown on Ni/Si substrate at 640 °C through tip growth mechanism, the carbon nanotubes could be grown on Ni/Si substrate at 700 °C through tip growth mechanism, and the carbon nanotubes could be grown on Ni/Ti/Si substrate at 700 °C through root growth mechanism.     

Effect of substrate temperature on microstructure and optical properties of single-phased Ag20 film deposited by using radio-frequency reactive magnetron sputtering method

Using a radio-frequency reactive magnetron sputtering technique, a series of the single-phased Ag20 films are deposited in a mixture of oxygen and argon gas with a flow ratio of 2：3 by changing substrate temperature （Ts）. Effects of the Ts on the microstructure and optical properties of the films are investigated by using X-ray diffractometry, scanning electron microscopy and spectrophotometry. The single-phased Ag20 films deposited at values of Ts below 200℃ are （111） preferentially oriented, which may be due to the smallest free energy of the （111） crystalline face. The film crystallization becomes poor as the value of Ts increases from 100℃ to 225℃. In particular, the Ag20 film deposited at Ts=225℃ loses the （111） preferential orientation. Correspondingly, the film surface morphology obviously evolves from a uniform and compact surface structure to a loose and gullied surface structure. With the increase of Ts value, the transmissivity and the reflectivity of the films in the transparent region are gradually reduced, while the absorptivity gradually increases, which may be attributed to an evolution of the crystalline structure and the surface morphology of the films.