掺铥氟磷玻璃的结构、热学性质和光谱性质

制备了不同Al(PO3)3含量的掺铥系列氟磷玻璃,研究了其结构、热稳定性和光谱性质。随着Al(PO3)3含量的增加,该系列玻璃的密度降低,折射率增加,差热分析表明,转变温度、析晶起始温度、析晶峰温度和熔化温度增加。Al(PO3)3摩尔浓度在7%~9%时析晶稳定性最佳。采用归一化的拉曼光谱分析了材料的结构和声子状况,对于该系列氟磷玻璃,Al(PO3)3含量的增加不会影响声子能量,但使声子密度增大。测试了样品的吸收光谱,Tm3 的3H6→3F4在第三通信窗口的L波段有明显吸收。与在其它玻璃基质中相比,Tm3 的3F4能级对应能量偏高,3H4能级对应能量偏低,使得3H4→3F4跃迁波长较大,接近于增益迁移光纤放大器的放大波长。扎得奥菲而特(Judd-Ofelt)理论分析表明随着Al(PO3)3含量增加,离子强度参量Ω2增大,Ω6保持相对稳定,Tm3 的能级寿命降低。     

高频燃烧红外吸收光谱法测定钨钛合金中碳含量

建立高频燃烧红外吸收光谱法测定钨钛合金中碳含量的分析方法。在1980 W分析功率下,称取0.3 g样品,以2.0 g钨锡及0.5 g纯铁混合助熔,用高频红外分析仪测定碳。碳的含量在0.013%~0.050%范围内与红外吸收峰面积线性相关,相关系数为0.9993。碳的测定下限为3.6μg/g,方法检出限为1.08μg/g。该法测定结果的相对标准偏差为2.97%~4.11%(n=8),碳的加标回收率为96.2%~103.1%。该方法能够满足合金中碳含量的分析要求。     

Er~(3+)铋铅锶玻璃吸收光谱和上转换光谱

制备了新型掺Er3+铋铅锶玻璃,研究了玻璃的吸收光谱和上转换光谱性质,应用Judd-Ofelt理论计算了铋铅锶玻璃的3个强度参量Ωt(t=2,4,6),分别为Ω2=3·27×10-20cm2,Ω4=1.15×10-20cm2,Ω6=0.38×10-20cm2。计算了Er3+离子的振子强度、自发辐射跃迁几率、荧光分支比和辐射寿命等光谱参数。研究了上转换发光强度随泵浦激光功率的变化,上转换荧光525,546和657nm曲线的斜率分别为1·86,1·88和1·85,表明红、绿光发射均为双光子吸收过程。     

碱熔融-电感耦合等离子体原子发射光谱法测定氧化铟锡烧结混合粉中5种杂质元素

采用氢氧化钠熔融样品,热水浸取后盐酸酸化,建立了碱熔融-电感耦合等离子体原子发射光谱(ICP-AES)法测定氧化铟锡烧结混合粉中Fe、Ca、Mg、Al和Si等元素的分析方法.试验结果表明:称取0.500 0 g试样,加入0.80 g氢氧化钠,在灰化炉中熔融120 min,可将样品完全溶解.基体铟和锡的干扰采用基体匹配法消除,被测元素之间没有光谱干扰.钠盐对硅的测定有一定影响,可在标准溶液中加入一定量氢氧化钠予以消除.对方法进行精密度和加标回收试验,测得结果的相对标准偏差均小于5%,方法加标回收率在90%~105%之间.     

Frequency Upconversion Emission of Er^3＋-Doped Strontium-Lead-Bismuth Glasses

Er^3 -doped strontium-lead-bismuth glasses for developing potential upconversion lasers have been fabricated and characterized. Under 975 nm excitation, intense green and red emissions centred at 525, 546, and 657nm,corresponding to the transitions ^2H11/2 → ^4I15/2, ^4S3/2 → ^4I15/2, and ^4F9/2 → ^4I15/2, respectively, were observed at room temperature. The upconversion mechanisms are discussed based on the energy matching and quadratic dependence on excitation power, and the dominant mechanisms are excited state absorption and energy transfer upconversion for 525 and 546nm emissions, and energy transfer upconversion for 657nm emission.     

Physical Properties of Novel Lead-Bismuthate Glasses with Large Transmitting Windows

Novel lead-bismuthate glasses with low OH concentration have been obtained in the Bi2O3-PbO-SrO system. The role of the different components in the glass formation has been explored from the density, refractive index measurements, indicating that the physical properties are mainly agected by Bi2O3 and PbO contents. The densities and refractive indices of these glasses are in the ranges of 7.639-7.699 g/cm^3 and 2.47-2.94, respectively. A wide transmitting window from visible to infrared (IR) regions and good thermal stability for some compositions of these g/asses have been observed, which make them appealing candidates for different optical applications suc has upconverting phosphors, new laser materials, optical waveguides and crystal-free fibre drawing.     

ICP–AES法测定锑铍芯块中铅、铁、锰和镁

建立电感耦合等离子体原子发射光谱(ICP–AES)测定锑铍芯块中铅、铁、锰和镁杂质元素的方法。对溶液酸度的选择、光谱和基体干扰等进行了试验和讨论,在优化仪器工作参数的条件下,通过基体匹配,有效消除了基体干扰的影响。铅、铁、锰、镁的质量浓度在0.05~10.0μg/mL范围内与其光谱强度呈良好的线性关系,线性相关系数大于0.999。铅、铁、锰、镁的检出限在0.5~5.3μg/L之间,测定结果的相对标准偏差为0.9%~2.9%(n=7),加标回收率为92%~106%。电感耦合等离子体原子发射光谱法与原子吸收光谱法对照,测定结果相符合。该方法准确可靠,可用于锑铍芯块中铅、铁、锰和镁杂质元素的测定。     

蔡氏电路的功能全同电路与拓扑等效电路及其设计方法

基于经典蔡氏电路方程的电容电压与电感电流变量及其状态方程归一化特点,提出了三种标度化、优化的电路设计方法:一种是方程变量都为电压的5运放电源限幅蔡氏电路,便于大规模集成;两种二极管非线性构成的功能全同蔡氏电路,与限幅非线性电路优势互补,可供大规模集成的细胞神经网络系统设计;同时,给出了与蔡氏电路为微分同胚电路的优化三次方蔡氏电路.各电路设计方法适用于以三折线为主的三次型混沌电路.最后,将本文提出的电路设计方法应用于混沌保密通信,实验表明该方法具有实用性和一定的应用价值.     

Intense frequency upconversion fluorescence of Er~(3+)/Yb~(3+) co-doped lithium-strontium-lead-bismuth glasses

Infrared-to-visible upconversion fluorescence of Er3+/Yb3+ co-doped lithium-strontium-lead-bismuth (LSPB) glasses for developing potential upconversion lasers has been studied under 975-nm excitation. Based on the results of energy transfer efficiency and upconversion spectra, the optimal Yb3+-Er3+ concentration ratio is found to be 5:1. Intense green and red emissions centered at 525, 546, and 657 nm, corresponding to the transitions 2H11/2→4 I15/2, 4S3/2→4 I15/2, and 4F9/2→4 I15/2, respectively, were observed. The quadratic dependence of the 525-, 546-, and 657-nm emissions on excitation power indicates that a two-photon absorption process occurs under 975-nm excitation. The high-populated 4I11/2 level is supposed to serve as the intermediate state responsible for the upconversion processes. The intense upconversion luminescence of Er3+ /Yb3+ co-doped LSPB glasses may be a potentially useful material for developing upconversion optical devices.     

高频燃烧红外吸收光谱法测定高纯铝粉中碳含量

高纯铝粉在粉末冶金领域应用广泛,其碳含量的高低对材质的物理性能有较大影响,研究快速准确测定高纯铝粉中碳含量方法具有实际意义。采用高频感应燃烧红外碳硫仪测定高纯铝粉中碳含量,优化实验条件,建立高纯铝粉中碳含量测定的高频燃烧红外吸收光谱法。实验表明,称取0.1 g试样,在1980 W分析功率下,按照2.4∶0.2∶0.2质量比例搭配钨、锡、铁助熔剂碳分析效果最佳。将该方法应用于试样中(碳质量分数为0.023%)碳的测定,相对标准偏差RSD=3.7%(n=11)。在试样中加入碳标准物质进行加标回收实验,加标回收率为99.0%~102%。方法检出限为0.0003%,测定下限为0.0030%。方法满足高纯铝粉中碳含量的快速检测要求。