Design of high T g Zr-based metallic glasses using atomistic simulation and experiment

In this paper, we systematically investigate local atomic structures of Zr_100?x Al _x (0???x???72) alloys using molecular dynamics simulations. Radial distribution functions of Zr-Al configurations at 300 K indicate that Zr-Al metallic glasses form only when the Al atomic concentration is larger than 32%. Voronoi polyhedral analysis shows that Zr₄₀Al₆₀ has the highest fraction of ?0,0,12,0? icosahedra around Al atoms, which are characteristic of amorphous microstructures. Variations of thermal expansion coefficient and heat capacity of Zr_100?x Al _x (40???x???72) metallic glasses as a function of temperature from 1100 to 800?K reveal that Zr₄₀Al₆₀ has the highest transition temperature of 1008?K. To confirm the simulation results, Zr-Al metallic glasses were fabricated using co-sputtering deposition; differential scanning calorimetry testing suggests the highest crystallisation-onset temperature of above 920?K is within Zr_100?x Al _x where 43?<?x?<?61. The experimental finding is in a good agreement with the simulation predictions.     

Effect of Fe on the glass-forming ability,structure and devitrification behavior of Zr–Cu–Al bulk glass-forming alloys

We report on the glass-forming ability and devitrification behavior of Zr₆₀Cu₃₀Al₁₀, Zr₆₀Cu₂₅Al₁₀Fe₅ and Zr_62.5Cu_22.5Al₁₀Fe₅ bulk glass-forming alloys on heating. The effect of Fe addition on the structure of Zr–Al–Cu alloys is also discussed. Crystallization kinetics and structural changes in the glassy alloys were studied using X-ray diffraction, transmission electron microscopy, differential scanning and isothermal calorimetry methods. The results indicate that good glass-formers, such as Zr_62.5Cu_22.5Al₁₀Fe₅, are located somewhat beyond the equilibrium eutectic point. Possible phase separation in the supercooled liquid on heating and electron beam-induced in situ crystallization are observed and discussed.     

铈掺杂高钆镥氧化物玻璃制备和光谱性能

实验中采用高温熔融法制备了一系列高钆镥硼硅酸盐新型玻璃体系样品,研究了这种新型玻璃体系的玻璃形成区,测量了样品的玻璃稳定性和密度。结果表明,玻璃体系的玻璃形成区较广,玻璃稳定性良好（析晶温度与转变温度的差为262 ℃）,且玻璃样品的密度达到5 g/cm3。以此种玻璃体系作为基质掺入Ce3+离子,测量其透过光谱、激发光谱、发射光谱、X射线激发发射光谱以及Gd3+离子的衰减时间。结果表明,玻璃的透过性能适合Ce3+离子的掺杂,并且Gd2O3和Lu2O3对闪烁体发光都具有积极的影响,同时研究了Gd3+离子和Ce3+离子的能量传递机理及最佳能量传递掺杂摩尔比。从玻璃的物理性能和光谱性能考虑,这种闪烁玻璃系统具有广泛应用于高能物理材料中的一定潜力。     

利用分形法表征光学元件中高频相位畸变

针对神光Ⅲ主机装置使用的光学元件,基于分形理论,分析中高频相位畸变的统计分布特征,指出其满足分数布朗随机场,并利用结构函数法对分形维数进行计算,统计结果显示,大口径钕玻璃片的分形维数在2.34~2.43之间。利用局部稳态的随机中点位移法,提出一种新的表征光学元件相位的方法,将分形维数作为参数,可衡量中高频相位畸变,对高功率激光光学元件的评价有参考意义。     

雾玻璃上的彩色环

向一个冷玻璃上哈气,在玻璃表面会形成水雾.透过起雾的玻璃去观察白光光源,会看到有多层彩色环(内层蓝色,外层红色),并且在中央会出现白色亮斑.利用散射光干涉的模型解释了彩色圆环的成因.     

Fe对掺钕磷酸盐激光玻璃激光性能的影响

 在理论分析的基础上,具体讨论了Fe质量分数小于10^-4对1 053 nm处光吸收损耗和Nd³⁺无辐射跃迁几率的影响规律,发现Fe在1 053 nm处的光吸收损耗和Nd³⁺无辐射跃迁能量转移都与Fe质量分数成平方关系增长, Fe对1 053 nm光吸收的影响较大而Fe与Nd³⁺之间的能量转移不足50 Hz。这对生产过程中Fe含量的控制有重要指导意义。     

偏磷酸根(PO-3)对氟铝酸盐玻璃透光性能影响

在氟铝酸盐玻璃（AMCSBY）中引入Ba(PO3）2替代BaF2,替代公式为10MgF2-20CaF2-(10-x)BaF2-10SrF2-15YF3-35AlF3-xBa(PO3)2(x=,2,4,6,8)。对玻璃进行了差热分析，结果表明，在氟铝酸盐玻璃中引入偏磷酸盐使玻璃形成能力大大提高；测量了玻璃从紫外到红外的透过光谱和紫外吸收光谱，在玻璃中引入偏磷酸钡使玻璃中红外透过能力下降，红外吸收边带移向短波段，玻璃紫外透过能力得到提高。紫外吸收边带移向紫外波段，由于PO3^-的影响，O－H吸收峰由2830nm移到3145nm。     

光纤连接器

介绍了光纤连接器的结构、端面形状、技术指标要求以及近几年发展起来的新型光纤连接器。对光纤连接器的关键技术———氧化锆陶瓷 (PSZ)插针体的制造进行了详细的分析。结果表明 ,生产陶瓷插针的设备和工艺相对比较复杂 ,一次性的固定投入较多 ,只有达到一定的生产规模才能产生效益     

Investigations of Solid State Dynamics at the NRSSR Beamline at PETRA II. An Overview

The present status of the new nuclear resonance beamline PETRA 1 at HASYLAB, DESY, Hamburg is described. Besides an overview of the experimental setup some examples of recent experiments are given. Those cover the main applications, i.e., inelastic scattering from iron alloys and quasielastic scattering from glass-forming liquids. This revised version was published online in August 2006 with corrections to the Cover Date.