Irradiation effects of CO2 laser parameters on surface morphology of fused silica

To understand the surface morphology evolution of fused silica induced by 10.6-μm CO2 laser irradiation at different parameters,this paper reports that optical microscopy,profilometry,and hydrophilicity tests are utilized to characterize the surface structure and roughness of the laser irradiated area. The results show that three typical surface morphologies and two typical hydrophilicity test images are observed at different laser powers and pulse durations. The correlations between surface temperature and surface morphology as well as hydrophilicity behaviours are presented. The different hydrophilicity behaviours are related to surface structures of the laser-induced crater and thermal diffusion area. The thermal diffusion length monotonously increases with increasing laser power and pulse duration. The crater width is almost determined by the laser beam size. The crater depth is more sensitive to the laser power and pulse duration than the crater width.     

The effect of Si content on the martensitic transformation temperature of Ni55.5Fe18Ga26.5-xSix alloys

This paper investigates the effects of substitution of Si for Ga on the martensitic transformation behaviours in Ni-Fe-Ga alloys by using optical metallographic microscope and differential scanning calorimetry (DSC) methods. The structure type of Ni55.5Fe18Ga26.5-xSix alloys is determined by x-ray diffraction (XRD),and the XRD patterns show the microstructure of Ni-Fe-Ga-Si alloys transformed from body-centred tetragonal martensite (with Si content x = 0) to body-centred cubic austenite (with x = 2) at room temperature. The martensitic transformation temperatures of the Ni55.5Fe18Ga26.5-xSix alloys decrease almost linearly with increasing Si content in the Si content range of x ≤ 3. Thermal treatment also plays an important role on martensitic transformation temperatures in the Ni-Fe-Ga-Si alloy. The valence electronic concentrations,size factor,L21 degree of order and strength of parent phase influence the martensitic transformation temperatures of the Ni-Fe-Ga-Si alloys. An understanding of the relationship between martensitic transformation temperatures and Si content will be significant for designing an appropriate Ni-Fe-Ga-Si alloy for a specific application at a given temperature.     

不同方法合成蓝宝石与天然蓝宝石的谱学对比研究

蓝宝石作为珍贵的彩色宝石深受人们喜爱,随着宝石合成技术的不断发展,市面上已有许多种合成方法制成的合成蓝宝石,常规的宝石学鉴定不能简单准确的区分天然蓝宝石与不同合成方法的合成蓝宝石。论文利用紫外-可见-近红外光谱仪对蓝宝石进行光谱分析,发现天然蓝宝石具有387 nm、452 nm、566 nm吸收峰,而提拉法、焰熔法和泡生法合成蓝宝石则无这些吸收峰;提拉法和焰熔法合成蓝宝石都具有600 nm附近的吸收带;泡生法合成蓝宝石存在660 nm附近的吸收峰,其他三种蓝宝石无此吸收峰。通过拉曼光谱特征峰拟合分析与SPSS单因素方差分析,发现天然蓝宝石和不同方法合成蓝宝石的半高宽值存在显著差异,天然蓝宝石的半高宽值大于10.0 cm^(-1),三种合成蓝宝石的半高宽值小于10.0 cm^(-1);泡生法合成蓝宝石半高宽集中在8 cm^(-1)附近,而焰熔法合成蓝宝石的半高宽普遍在8 cm^(-1)~10cm^(-1)范围内,提拉法合成蓝宝石半高宽则分布在6 cm^(-1)~8 cm^(-1)范围内。对比研究紫外-可见-近红外光谱与拉曼光谱的显著谱图特征差异,可简单、有效、无损的区分鉴定天然蓝宝石与不同合成方法合成的蓝宝石。     

Effects of Vacuum on Fused Silica UV Damage

Damage points induced by 355 nm laser irradiation increase more quickly on the surface of fused silica in vacuum of about 10^-3 Pa than in atmospheric air at the same fluence. The larger concentration of point defects in vacuum is confirmed by photoluminescence intensity. X-ray photoelectron spectroscopy and infrared absorption indicate the formation of sub-stoichiometric silica on the surface. The degradation mechanism of fused silica in vacuum is discussed.     

氮气退火对二氧化钛薄膜光学性能的影响

 提出了一种利用离子注入和后续退火制备氮掺杂TiO₂薄膜的方法。首先在室温下向石英玻璃中注入Ti离子,随后在氮气中退火到900 ℃,从而制备了氮掺杂的玻璃基TiO₂薄膜。SRIM2006程序模拟和卢瑟福背散射谱（RBS）研究表明注入离子从样品表面开始呈高斯分布,实验结果和模拟结果吻合很好。X射线光电子能谱（XPS）研究结果表明注入态样品中形成了金属Ti和TiO₂,900 ℃退火后金属Ti转变成TiO₂,同时N原子替代少量的晶格O原子形成了O－Ti－N化合物。紫外-可见吸收光谱（UV-Vis）结果显示,当退火温度至500 ℃时,在吸收光谱中开始出现TiO₂的吸收边,随退火温度升高到900 ℃,由于O－Ti－N化合物形成,TiO₂的吸收边从3.98 eV红移到3.30 eV,TiO₂吸收边末端延伸到可见光区,在可见光区的吸收强度明显增加。     

环境气氛压强对熔石英紫外激光损伤阈值的影响

 利用1∶1, S∶1, R∶1方法,测试了不同真空度（10-3～105 Pa）和不同气氛（空气、氮气、氧气）环境下熔石英351 nm激光损伤阈值,测试结果表明,用1∶1, S∶1方法测试得到的阈值在不同气氛压强下几乎相等;R∶1损伤阈值受气压的影响较大,在小于等于10³ Pa气压下,较105 Pa气压的阈值降低28%～41%;但R∶1损伤阈值同气氛的关系不大,在同气压下差别小于10%,在测量值误差范围内。利用50%破坏几率对应的损伤阈值Fth（R∶1）一半的激光能量密度辐照样品,考察其抗多脉冲辐照的能力,分析表明,在同样的能量密度辐照下,10³ Pa空气及氮气环境和105 Pa氮气环境下同样具有高的寿命;而10^-3 Pa高真空环境下其寿命较短,在10^-1 Pa低真空环境下其寿命最短。     

层间热处理对SiO2/ZrO2双层膜的影响

 以正硅酸乙酯和丙醇锆为前驱体,用溶胶-凝胶法在K9基片上提拉镀制SiO₂/ZrO₂双层膜。采用不同实验步骤制备了2个样品,样品1镀完SiO₂后直接镀ZrO₂ ,样品2镀完SiO₂经热处理后再镀ZrO₂。采用原子力显微镜、椭偏仪、紫外-可见分光光度计对薄膜进行表征。针对SiO₂/ZrO₂双层膜,考虑到膜间渗透的影响,采用３层Cauchy模型进行椭偏模拟,椭偏参数的模拟值曲线与椭偏仪的测量值曲线十分吻合,进而发现热处理可以使SiO₂/ZrO₂双层膜之间的渗透减少近23 nm,从而提高其峰值透射率。利用输出波长1.064 mm,脉宽8.1 ns的激光束对样品进行了损伤阈值的测试,用光学显微镜观察损伤形貌,结果发现两者损伤阈值分别为13.6 J/c2和14.18 J/cm²,均为膜的本征损伤。     

Rb-N_2(He)蒸气室压强及He、N_2气渗漏测量

利用原子吸收及谱线增宽方法测量了Rb-N_2(He)蒸气室中的气体压强.对Rb-N_2(He)蒸气室中的气体渗漏进行了检测,实验发现:对N_2气几乎观察不到明显的渗漏现象.对于Rb-He950torr的高压蒸气室60天后的气体渗漏量为19%,渗漏比较明显.测量了223-638torr范围Rb-N_2蒸气室的5P_(3/2)—5P_(1/2)精细结构碰撞转移截面.结果表明,随着温度升高,碰撞转移截面值也升高,温度为50℃、60℃、70℃时,碰撞转移截面分别为(1. 03±0. 32)×10~(-16)cm~2、(1. 36±0. 38)×10~(-15)cm~2、(8. 96±1. 02)×10~(-15)cm~2.压强在638torr时,碰撞转移截面随着温度升高增加较快,70℃以后碰撞转移截面迅速增加.     

THE APPLICATION OF HMQC-TOCSY TO THE PLANT GLYCOSIDES AND PLANT CYCLOPEPTIDES

核磁共振HMQC-TOCSY二维技术可在氢谱方向和碳谱方向分别得到独立的自旋系统内氢核和碳核的全相关信息.该技术对于分子内具有多个自旋系统的植物环肽和配糖体的结构解析尤为适用.本文以环肽annosquamosin A和三萜皂甙prostratoside A为例说明该技术在这两类化合物中的应用.     

Bending of a circular cylinder containing a crack

The study of bending of cracked circular cylinders is of more significance. The bending of cylinders containing radical crack or cracks was discussed by refs. [1]–[4] and that of concentrically craked circular cylinders was studied by [5]. Continuing [6] and using complex variable methods in elasticity, this paper deals with the bending problems of a circular cylinder, containing an internal linear crack at any position under an acting force perpendicular to the crack. The general forms of displacements, stresses, and stressintensity factors, expressed in terms of series, are obtained and to this bending problems with small Ah are presented good approximate formulas for the stress-intensity factors whose variations with the center of the crack are analysed. Finally, the twist angle per unit length and the center of bending for the radically cracked circular cylinder, one of whose crack-tips is located at the origin, have been computed and the results are almost the same as that calculated in [1].