Effect of Network Modifiers on Spectroscopic Properties of Erbium-doped Phosphate Glasses

The integrated absorption cross section ∑abs, peak emission cross section σemi , Judd-Ofeld intensity parametersΩ1 ( t = 2,4,6), and spontaneous emission probability AR of Er3 ions wre determined for Erbium doped alkali and alkaline earth phosphate glasses. It is found the compositional dependenee of σemi is almost similar to that of ∑abs , which is determined by the sum of Ω1 (3Ω2 10Ω4 21Ω6 ). In addition, the compositional dependence of Ω1, was studied in these glass systems. As a result, compared with Ω4 and Ω6 , the Ω2 has a stronger compositional dependence on the ionic radius and content of modifiers. The covalency of Er-O bonds in phosphate glass is weaker than that in silicate glass, germanate glass, aluminate glass, and tellurate glass,since Ω6 of phosphate glass is relatively large. AR is affected by the covalency of the Er3 ion sites and correspands to the Ω6 value.     

The effect of OH~- groups on the spectroscopic properties of erbium-doped tellurite glasses

With the rapid development of computer networks and other data-transmitting ser-vices, the demand for the increase of transmission capacity of the long distance trans-mission system is urgent. However, the conventional SiO2-based EDFA is limited for its small bandwidth. The Er3+-doped tellurite glass exhibits a larger stimulated-emission cross section and a broader emission bandwidth at the third communication window (1.55 μm) than that of silicate, phosphate, and germanate glasses, which c…     

Influence of addition of B2O3 on properties of Yb^3＋-doped phosphate laser glass

The three host glasses doped with Yb^3＋ were prepared by means of conventional melt quenching technology, and the influence on physical and spectral properties of phosphate glass due to addition of B2O3 was investigated and compared with silicate glass. The results show that due to the existence of OH^- impurities which induce the non-radiative route, the fluorescence lifetime of phosphate glass is shorter, so silicate glass has better spectral properties than phosphate glass. Silicate glass has more excellent thermal-mechanical properties than phosphate glass, but with the addition of B2O3, thermal-mechanical properties of phosphate glass are improved greatly without fluorescence quenching effect, and this kind of borophosphate glass will be the candidate to be used in high average power solid state laser.     

低温下掺镱磷酸盐激光玻璃的光谱和激光特性

根据低温下测得的Yb3磷酸盐玻璃的吸收光谱和荧光光谱,计算了Yb"离子在磷酸盐玻璃中的能级结构,解释了荧光寿命在低温下变化异常的原因,在低温下采用940nm的LD泵浦Yb3+磷酸盐玻璃获得了准连续激光输出,8K时最大输出功率为2mW,斜率效率为4%,激光中心波长为1000nm.     

Preparation and Spectroscopic Properties of Ce-Doped High-Silica Glass

In order to develop a novel electric light source, the doped high-silica glass was studied on the preparation and spectroscopic properties . The porous glasses were made firstly and were then immersed in the solution containing Ce ion. Thereafter, the high-silica glasses containing Ce ion were prepared by sintering the porous preform. The spectroscopic properties were studied before and after heat-treatment in H2 . The experimental results indicate thai, the suitable temperature schedules are the most important to prepare doped high-silica glass. The study of the spectra shows that Ce ion can be reduced to low valence state when it is heat-treated in H2 . It can be used to adjust the UV aut-off wavelength of high-silica glass by changing the valence state of Ce ion.     

1000MW汽机基础动力特性优化

汽轮发电机基础的动力特性对电厂的安全运营有着重要影响,通过建立基础的动力方程以及优化模型,分析了基础动力优化理论和优化过程,针对某1000 MW级框架式汽机基础进行了多方案的优化研究,最终取得了同时降低振幅和混凝土用量的优化目标.     

聚合矿物复合材料组分优化与机械性能

聚合矿物复合材料,是由粘结剂包括树脂、固化剂、增韧剂等与矿物质混合而成的复合材料,它具有高阻尼、耐腐蚀、低成本等特点,是制造机械基础件的理想材料.介绍了聚合矿物复合材料的组分优化方法,提出了用正交试验方法进行复合材料的配方优化及结果分析,并总结了组分对该材料机械性能的影响规律.     

掺铒碲酸盐玻璃的热稳定性和光谱性能

研究了掺铒TeO2-BaO-TiO2-La2O3碲酸盐玻璃的热稳定性及Er^3＋离子的吸收和荧光光谱性质。应用Judd-Ofelt理论计算了玻璃的强度参数Ω1（t=2、4、6）、Er^3＋离子在玻璃中的谱线强度、自发辐射几率以及辐射寿命。应用McCumber理论计算了受激发射截面。分析了TiO2对碲酸盐玻璃热稳定性和光谱性能影响，碲酸盐玻璃中含0—5％摩尔分数TiO2时可以有效地改善玻璃的热稳定性。该玻璃系统具有较好的增益带宽和热稳定性，适合于作为掺铒碲酸盐光纤放大器用基质材料。     

Magnetic Properties of γ-Fe2O3 Nanoparticles Prepared by Laser Ablation

A new method of preparing nanoparticles by pulsed-laser ablation of a tiny wire was reported, and pure maghemite （ γ-Fe2 O3 ） nanoparticles were synthesized by this method in a mixed gas flux of N2 and O2 at atmospheric pressure. The obtained γ-Fe2 O3 nanopartiles were in the range of 5 to 80 run in diameter and largely spherical in shape. Structural characteristics and morphologies of the nanoparticles were characterized by XRD and TEM , respectively. Moreover, magnetic properties of the obtained 7- Fe, O3 nanopartiles in the temperature range of 300 to 773 K were investigated. The experimental results demonstrate that the squareness value of the hysteresis loop decreases with increasing temperature. Both the coercivity and the saturation magnetization of the γ-Fe2 O3 nanoparticles show a constantly decrensing trend with increasing temperature up to the occurrerwe of the transformation from γ-Fe2O3 to α-Fe2O3. Especially, at the temperature of 773 K, the γ-Fe, O3 begins to transform to the α-Fe2 O3 phase and the hysteresis loop becomes unclosed .     

Nd:GdVO_4晶体的光谱和激光特性

Nd :GdVO4晶体的吸收谱和荧光谱表明 ,晶体在 80 8.5nm有吸收峰 ,其发射波长 91 2 .6nm ,1 0 63.1nm和 1 341 .3nm .晶体中掺Nd浓度为 1 .5 6at%Nd :GdVO4的4F3/ 2 荧光寿命为 1 0 0μs.用 3W激光二极管 (LD)泵浦 1mm厚的Nd :GdVO4晶体 ,得到了 1 .72W、1 0 63nm和 80 0mW、1 341nm的输出光     

激光热处理对铜基摩擦片组织与性能的影响

研究激光处理对摩擦片的组织与性能的影响具有重大实用价值。观测发现激光处理的摩擦片的铜基体、石墨、孔隙度均有所变化。采用定量金相技术测定了激光处理前后摩擦片的孔隙度．激光处理使铜基体的显微硬度明显提高．分析了变化原因及对性能的影响．激光处理提高了摩擦片的性能，有利于大幅度提高其使用寿命。     

激光强化处理参数对轧辊表面性能的影响

通过试验，研究了激光功率、光斑直径、扫描速度、搭接量和合金粉含量等激光处理工艺参数对轧辊表面性能的影响，结果表明，轧辊表面经激光淬火处理后。性能稳定，耐磨性和抗疲劳性均有所提高，达到了生产要求．     

Microstructure and properties of laser direct deposited CuNi17A13Fe1.5Cr ahoy

Thin walls of a copper-base alloy with the nominal composition CuNi17A13Fe1.5Cr were successfully prepared by laser direct deposition additive manufacturing.The microstructure,as revealed by optical and scanning electron microscopy,indicated that the deposited material was fully dense and with a dendritic microstructure.The dendrites are parallel to the build-up direction,which is also the heat conduction direction during deposition.X-ray diffraction analysis results show that the deposited material is composed of a single phase and a copper-based solid solution.Some precipitate particles of metal silicides were observed in the interdendritic region by scanning electron microscopy.The ultimate tensile strength along the laser scanning direction reaches 735 MPa.The hardness is about Hvo.1 300.     

Origin of Chinese ancient glasses—study on the earliest Chinese ancient glasses

The earliest Chinese ancient glasses before the West Han Dynasty (200 BC) from different regions are studied. The glass samples were unearthed from Hunan, Hubei, Yunnan, Sichuan, Guizhou, Guangdong and Xinjiang of China. The chemical composition of these glasses samples is analyzed by proton induced X-ray emission (PIXE) technique, energy dispersive X-ray fluorescence (EDXRF) method and inductively coupled plasma atomic emission spectrometry (ICP-AES). It is shown that the glass chemical compositions belong to barium-lead silicate BaO-PbO-SiO₂, potash soda lime silicate K₂O (Na₂O)-CaO-SiO₂ (K₂O/Na₂O>1), soda potash lime silicate Na₂O (K₂O)-CaO-SiO₂ (K₂O/Na₂O<1) and potash silicate K₂O-SiO₂ glass systems, respectively. The origins of the earliest Chinese ancient glasses are discussed from the archaeological and historical points of view. These four types of Chinese ancient glasses were all made in Chinese territory using local raw materials. The glass preparation technology was related to the Chinese ancient bronze metallurgy and proto-porcelain glaze technology. The glass technology relationship between the East and the West is analyzed at the same time.     

Microstructure and properties of laser direct deposited CuNi17Al3Fe1.5Cr alloy

Thin walls of a copper-base alloy with the nominal composition CuNi17Al3Fe1.5Cr were successfully prepared by laser direct deposition additive manufacturing. The microstructure, as revealed by optical and scanning electron microscopy, indicated that the deposited material was fully dense and with a dendritic microstructure. The dendrites are parallel to the build-up direction, which is also the heat con-duction direction during deposition. X-ray diffraction analysis results show that the deposited material ...     

Origin of Chinese ancient glasses——study on the earliest Chinese ancient glasses

The earliest Chinese ancient glasses before the West Han Dynasty (200 BC) from different regions are studied. The glass samples were unearthed from Hunan, Hubei, Yunnan, Sichuan, Guizhou, Guangdong and Xinjiang of China. The chemical composition of these glasses samples is analyzed by proton induced X-ray emission (PIXE) technique, energy dispersive X-ray fluorescence (EDXRF) method and inductively coupled plasma atomic emission spectrometry (ICP-AES). It is shown that the glass chemical compositions belong to barium-lead silicate BaO-PbO-SiO2, potash soda lime silicate K2O (Na2O)-CaO-SiO2 (K2O/Na2O>1), soda potash lime silicate Na2O (K2O)-CaO-SiO2 (K2O/Na2O＜1) and potash silicate K2O-SiO2 glass systems, respectively. The origins of the earliest Chinese ancient glasses are discussed from the archaeological and historical points of view. These four types of Chinese ancient glasses were all made in Chinese territory using local raw materials. The glass preparation technology was related to the Chinese ancient bronze metallurgy and proto-porcelain glaze technology. The glass technology relationship between the East and the West is analyzed at the same time.     

CO_2激光辐照对PZT-4陶瓷压电性能的影响

常温常压下,采用CO2激光辐照带有电极的PZT-4陶瓷片,当激光辐照时间分别为2、5和10 s时,在适当的激光功率密度下可使其压电应变常数d33从380 pC/N下降为零。系统地研究了激光功率密度和激光辐照时间对PZT-4陶瓷压电性能影响的规律。XRD、拉曼光谱和退火实验结果表明:CO2激光辐照使d33下降为零的原因是由于激光热效应导致PZT-4陶瓷的电畴排列失序,极化状态消失;而激光辐照未使其物相发生变化。     

Preparation and mechanical behavior of Mg-based bulk metallic glasses and their matrix composite

Mg87-xCuxDy13(x=22,27,32) bulk metallic glasses (BGMs) with a diameter of 6-8 mm and in-situ Mg phase reinforced Mg70Cu17Dy13 BMG matrix composite with a diameter of 3 mm have been prepared by copper mould casting. The glass forming ability (GFA) of Mg-Cu-Dy alloys have been investigated by differential scanning calorimetry (DSC) and X-Ray diffraction (XRD) and tne mechanical properties have been measured. Results show that Mg87-xCuxDy13(x=22,27,32) alloys in the Mg-Cu-Dy alloy system exhibit excellent GFA, and Mg60Cu27Dy13 alloy has the largest GFA among these alloys. And In-situ Mg phase reinforced Mg70Cu17Dy13 BMG matrix composite exhibits some work hardening and a high fracture compressive strength of 702.38 MPa and some plastic strain of 0.81%. The improvement of the mechanical properties is attributed to the fact that the Mg phase distributed in the amorphous matrix of the alloy has some effective load bearing and plastic deformation ability to restrict the expanding of shear bands and cracks and produce its own plastic deformation.     

瓶罐玻璃的配料优化

给出了瓶罐玻璃配合料优化的数学模型，并对大连玻璃制品厂生产罐头瓶原配方进行优化计算。实践表明，所用的优化方法不仅满足其生产工艺要求，而且具有一定的经济效益。     

鱼油微胶囊制备工艺优化及其理化性质研究

为了解决鱼油在食用过程中易氧化及带有鱼腥味等问题,以豌豆蛋白(PPI)-阿拉伯胶(GA)复合物为壁材,冷冻干燥制备鱼油微胶囊.通过正交试验研究了壁材质量分数、芯壁比、均质压力、PPI与GA质量比等4个因素对鱼油包埋率的影响,得到鱼油微胶囊制备的最佳工艺:壁材质量分数5％,PPI与GA质量比1∶1,均质压力50 MPa,...