Spectroscopic analysis and magnetic susceptibility of CuO-TeO2-V2O5 glasses

This article reports on the structure of the glassy system xCuO-65TeO₂-(35−x)V₂O₅, 5≤x≤10 mol% which was studied using infrared (IR) and Raman spectroscopy methods as well as magnetic susceptibility measurements. IR and Raman spectroscopy analysis reveals the presence of four main absorption bands attributed to [TeO₃], [TeO₄], [VO₄], and [VO₅] structure units. It suggests that Cu²⁺ ions occupy the available open spaces of the Te-O network without straining the bonds too much. Increasing the concentration of Cu²⁺ ions beyond 5 mol% results in the modification of the glass by straining and locally distorting the surrounding of the Te-O network. The magnetic susceptibility of these materials was investigated in the temperature range of 5-200 K revealing the paramagnetic behavior described by the Curie-Weiss law and indicating the presence of weak antiferromagnetic exchange interactions between Cu ions. The magnetic entropy change of the glasses was determined based on the temperature and magnetic field dependence of magnetization.     

Controlling subsurface damage in neodymium-doped phosphate glass

We investigate the removal mechanism of neodymium-doped phosphate glass dominated in loose abrasive grinding and bound abrasive grinding. Moreover, we investigate the surface roughness and subsurface damage change with optical fabrication parameters, such as different spindle speed, load and abrasive size under different grinding processes in details. For a range of experimental conditions, we find that fracture is the principal removal mechanism for loose abrasive grinding, while plastic scratching is the dominating mechanism for bound abrasive grinding. The load has more influence on subsurface damage for bound abrasive grinding than for loose abrasive grinding. However, the spindle speed has different effect on subsurface damage produced with loose abrasive grinding and bound abrasive grinding. Moderate spindle speed and low load is preferred to produce smaller subsurface damage for loose abrasive grinding. Moreover, higher spindle speed and lower load are preferred to plastic scratching for bound abrasive grinding. Bound abrasive grinding produces 4 times lower surface roughness and 3 times lower subsurface damage than loose abrasive grinding.     

Prediction of spinodal wavelength in continuously cooled metallic liquid

The spinodal decomposition of a deeply undercooled metallic liquid Zr_41.2 Ti_13.8Cu_12.5Ni₁₀Be_22.5 between 800 and 700 K is analysed in the framework of the theory of Cahn and Hilliard for continuous cooling, and the wavelength with maximum amplification is predicted, using as input parameters thermodynamic values gained in experiments. Electron microscopical studies show the microstructure of glass forming alloys Zr_41.2Ti_13.8Cu_12.5Ni₁₀Be_22.5. The as‐cast material exhibits a two phase mixture of amorphous regions with different compositions. Evidence for spinodal decomposition is given, and the computed maximum‐amplitude wavelength corresponds well with the one found in the experiments.     

Luminescence behavior of Tb ions in transparent glass and glass-ceramics containing CaF2 nanocrystals

Transparent glass-ceramics have been fabricated by heat treatment with 1.0 mol% Tb₂O₃-doped 45SiO₂-20Al₂O₃-10CaO-25CaF₂ aluminosilicate glass. The precipitated crystalline phase in the glass-ceramics is CaF₂ nanocrystals with a size of 15-27 nm and dispersed in the amorphous phase. Both photo- and radioluminescence measurements show that the increase of Tb³⁺ 545 nm line intensity by a factor of 4 and 3.5 is obtained in glass-ceramics with respect to the as-made glass, respectively.     

Vibro-acoustic behaviour of laminated double glazing enclosing a viscothermal fluid cavity

This paper presents a new numerical model to investigate the vibro-acoustic behaviour of two laminated glass plates enclosing a thin viscothermal fluid cavity. The aim of this work is to develop an original five layer (two skins plies, two adhesive films and a core ply) laminated plate finite element by mixing Kirchhoff and Mindlin plate’s theory. The formulation is based on the theory that accounts for the transverse shear in the adhesive films and in the core. The acousto-elastic model is established in dimensionless appropriate form including the effects of viscosity and thermal conductivity of fluid and by taking into account the fluid-structure interaction. The discretization of the energy functional by finite element method gives after minimisation a symmetrical coupled matrix system in which the acoustic matrices are frequency dependent. Therefore, an iterative procedure is derived to determine the eigenmodes of the coupled system. The modal approach is adopted to determine the vibro-acoustic system’s response. Then, the validation of the new laminate finite element model is achieved by comparing the sandwich plate results against data obtained from literature. Subsequently, predicted responses, such as the vibration transmissibility and the transmission loss of the coupled system, for a given laminated double glazing under an imposed homogeneous pressure are presented and discussed. Numerical results show the importance of both lamination and viscothermal fluid effects on double glazing vibro-acoustic behaviour.     

Different shapes of tracks in phlogopite, biotite and soda lime glass

Etched track opening geometries in Biotite, Phlogopite and soda-lime glass irradiated with swift heavy ions [¹⁹⁷Au(11.64 MeV/n), ¹³⁶Xe(11.56 MeV/n), ⁵⁸Ni(11.56 MeV/n)] at different angle of incidence have been studied using appropriate chemical etching technique. Different geometries (Hexagonal, irregular polygon, triangular in case of Biotite and Phlogopite, and circular & elliptical in case of soda lime glass detector) of heavy ion tracks are reported in the present investigations using optical microscope. The different shapes of these heavy ions track geometries are found to be related with various target-projectile parameters (viz: type of projectiles, energy, stopping power, angle of incidence of the projectile, density of defects and its reactivity with etchant, etching conditions and chemical structure of the detectors). The dependence of different shapes of heavy ion tracks in isotropic and anisotropic medium on the variation of radiation damage densities along the ion trajectories have also been discussed in the present paper.      

15波长输出的布里渊掺铒光纤激光器

多波长布里渊掺铒光纤激光器是一种新型的多波长光纤激光器,其原理是利用受激布里渊增益和掺铒光纤的线性增益,可以在常温下得到波长间隔约为0．08nm(～10GHz)的多波长输出。报道的布里渊掺铒光纤激光器,在布里渊抽运功率为1．7mW、980nm抽运功率为300mW的情况下得到稳定的15个波长(间隔～10GHz)的输出,这种激光器用作光传感器、光谱分析仪以及密集波分复用系统的光源。实验发现,输出波长的个数随着980nm抽运功率的增大而增加。另外,布里渊掺铒光纤激光器的信号功率主要来自于掺铒光纤的增益,而布里渊增益对它的影响不大。     

石英玻璃低能质子辐照损伤动力学研究

地面模拟研究了JGS3光学石英玻璃在真空、热沉和能量低于200keV的低能质子辐照下表面光学性能变化的基本规律．并建立了辐照损伤色心演化的动力学唯象模型。试验结果表明．大通量低能质子辐照对石英玻璃表层具有明显的表面损伤效应。随着辐照吸收剂量的增加,光密度变化先以线性规律迅速增加．加进一步增加时逐渐呈现饱和趋势;采用较高能量辐照作用后光密度变化出现饱和趋势的拐点提前,且饱和数值降低。根据对试验结果的分析,建立了低能质子辐照下石英玻璃色心演化的动力学模型．并给出了光密度变化的表达式。采用模型结果进行数学模拟,模拟曲线与试验结果曲线相似。因此所建立的动力学模型可以用来定量描述低能质子辐照下石英玻璃光学性能随辐照吸收剂量的变化规律。     

掺钕磷酸盐激光玻璃的光谱特性

掺钕激光玻璃广泛应用于核聚变、高功率激光放大器和光纤激光器等领域。磷酸盐玻璃热膨胀系数高、热稳定性和化学稳定性差、热机械强度低。通过改变玻璃组分,即添加Al2O3和F2,并改进制备工艺来降低热膨胀系数,除去铂和分子水。测量了磷酸盐玻璃中Nd3+离子的荧光光谱、吸收光谱及玻璃的热膨胀系数。根据吸收光谱计算掺钕磷酸盐激光玻璃的光谱参数。通过对掺钕磷酸盐玻璃的热膨胀系数的实际测量和计算,分析了玻璃的热稳定性。结果表明,在基质玻璃中引入Al2O3使激光玻璃的热膨胀系数可降低到α=38.75×10-7/℃,引入F2既达到了除水的目的又降低了玻璃的声子能量,提高了荧光发射的量子效率,并优化了光谱性能,拓展了掺钕磷酸盐激光玻璃的应用范围。     

磷酸铈共沉淀分离富集硫酸钴中痕量铅及铅的原子吸收光谱测定

提出了用磷酸铈(CePO4)作为共沉淀捕集剂分离富集CoSO4溶液中的痕量Pb2+,用火焰原子吸收光谱(FAAS)测定的方法。共沉淀效率受pH、Ce(NO3)3和H3PO4溶液用量的影响。结果显示,在溶液pH3.0～4.0时,CePO4能够定量共沉淀CoSO4溶液中的Pb2+,对于20mL的样品溶液,方法的检出限为5.59×10-2mg/L,铅的标准加入回收率为98.32%,排除了基体干扰,取得了较为满意的结果。