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| 1 | Segregation during crystal growth from melt and absorption cross section determination by optical absorption method显示文摘Segregation during crystal growth from melt under two conditions is studied by using crystal mass,which can be measured easily,as an independent variable,and a method to determine the effective segregation coefficient and absorption cross section of optical dopant is given.When the segregated solute disperses into the whole or just a part of melt homogenously,the concentration CS in solid interface will change by different formulas.If the crystal growth interface is conical and segregated solute disperses into melt in total or part,the solute concentration at r=2/3R,where r is the distance from the growth cross section center and R the crystal radius,is independent on the shape of the crystal growth interface,and its variation at r=2/3R can be regarded as the result from crystal growth in flat interface.With CS variation formula in solid and absorption cross section σ for optical dopant,the absorption coefficients along the crystal growth direction can be calculated,and the corresponding experimental value can be obtained through the crystal optical absorption spectra.By minimizing the half sum,whose independent variables are k,ΔW or σ,of the difference square between the calculated and experimental absorp-tion coefficients from one or more absorption peaks along the crystal growth di-rection,k and σ,or k and ΔW,can be determined at the same time through the Levenberg-Marquardt iteration method.Finally,the effective segregation coefficient k,ΔW and absorption cross sections of Nd:GGG were determined,the results fitted by two formula gave more closed effective segregation coefficient,and the value ΔW also indicates that the segregated dopant had nearly dispersed into the whole melt.Experimental results show that the method to determine effective segregation coefficient k,ΔW and absorption cross sections σ is convenient and reliable,and the two segregation formulas can describe the segregation during the crystal growth from melt relatively commendably. | ZHANG QingLi YIN ShaoTang SUN DunLu WAN SongMing | 2008 | Science China(Physics,Mechanics & Astronomy)2008，51，5： | 5 |
| 2 | Gamma-ray irradiation effect on the absorption andluminescence spectra of Nd: GGG and Nd: GSGGlaser crystals 显示文摘 | Dunlu Sun Jianqiao Luo Qingli Zhang | 2008 | Journal of Lu minesecencee2008，，128： | 1 |
| 3 | Co-precipitation synthesis and sintering of nanoscaled Nd∶Gd3Ga5O12 polycrystalline material显示文摘 | Zhang Qingli Yin Shaotang | 2005 | Materials Science & Engineering A2005，392，： | 1 |
| 4 | Study on Lattice Parameter Variance and Eutectic Reaction during Crystal Growth of Nd,Cr∶GSGG by Czochralksi Method显示文摘During the crystal growth of Nd, Cr∶GSGG by Czochralski method, in some cases eutectic reaction occurred in the nether region of the crystal, and the boule was divided into two obvious different parts, which is upper Nd,Cr∶GSGG crystal and the nether coexisting Nd,Cr∶GSGG and GdScO3. By X-ray powder diffraction, the structure change of NdCr∶GSGG crystal of Φ 27 mm×120 mm with eutectic along its grown direction <111> was studied. By the least square method and extrapolation function f=sinθ-sinθ1-t(t is an adjustable parameter), the lattice parameters of Nd,Cr∶GSGG and additional GdScO3 phase were computed. The results indicate that the lattice parameters of Nd,Cr∶GSGG increase along its growth direction, which changes from a=(1.25650±0.00007) nm of the top to (1.25798±0.00010) nm of the bottom. In the process of Nd,Cr∶GSGG growth, Gd3+ in Nd,Cr∶GSGG is partly replaced by Nd3+ with larger ionic radii, and the volatilization of Ga component results in its composition variance, which cause the lattice parameters increase along growth direction. In the eutectic section, there are the Nd,Cr∶GSGG and the second phase orthorhombic GdScO3. The lattice parameters of GdScO3 are a=0.5443±0.0007, b=0.5699±0.0005 and c=(0.7865±0.0009) nm, and that of Nd,Cr∶GSGG is (1.25798±0.00010) nm. In the final growth stage, excessive volatilization of Ga composition during the crystal growth causes the growth melt deflect of the Nd,Cr∶GSGG solid solution range seriously, and results in the eutectic reaction, and the outgrowth of Nd,Cr∶GSGG and GdScO3. So it is necessary to decrease the effect of gallium volatilization during the growth in order to avoid eutectic growth and obtain a high-quality Nd,Cr∶GSGG. | Zhang Qingli Yin Shaotang Sun Dunlu Shao Shufang Gu Changjiang | 2006 | Journal of Rare Earths2006，24，z1： | 0 |
| 5 | Lattice Parameter Change of Nd∶Gd3Ga5O12 Crystal with Growth Direction显示文摘The lattice parameter change of Nd∶GGG crystal was studied by X-ray powder diffraction and the least square fitting method. The results indicate that the lattice parameters of Nd∶GGG increase along the crystal growth direction. By analyzing the Nd∶GGG crystal structure and ions occupying site, the reason of lattice parameter change is mainly attributed to the volatilization of gallium ingredient and lead to the Ga vacancy sites(Oxygen octahedral center) were occupied by Gd3+ with large ionic radii, and that the substitute increases with the crystal growth direction. In addition, the Gd sites(oxygen dodecahedron center) were occupied by dopant Nd3+ with large ionic radii and the Nd3+ distribution coefficient in GGG crystal is smaller than 1, therefore, the substitute also increased with the crystal growth direction, which is another reason led to the lattice parameter increase along the crystal growth direction. In order to decrease the lattice parameter change and improve the crystal quality, some methods were adopted to restrain effectively the Ga2O3 volatilization and decrease the Nd3+ concentration change along the crystal growth direction. | Sun Dunlu Zhang Qingli Wang Zhaobing Su Jing Zhang Xia Shao Shufang Gu Changjiang Yin Shaotang | 2006 | Journal of Rare Earths2006，24，z1： | 0 |
| 6 | Basic properties of a new Nd-doped laser crystal: Nd:GdNbO4显示文摘一个做 Nd 的 GdNbO 4 单身者晶体用 Czochralski 技术成功地被种了。化学蚀刻方法被采用在 Nd 的结构的形态学学习缺点: 有磷的酸蚀刻剂的 GdNbO 4 水晶。机械性质(例如坚硬,收益力量,破裂坚韧,和易碎的索引) 系统地第一次根据 Vickers 坚硬测试成长得当的水晶被估计。Nd 的传播光谱: GdNbO 4 在房间温度在 3202400 nm 的波长范围被测量,并且吸收山峰被分配。为关于 Nd 的进一步的研究的结果抓住伟人意义: GdNbO 4 。 | Shoujun DING Qingli ZHANG Wenpeng LIU Jianqiao LUO Dunlu SUN | 2017 | Frontiers of Optoelectronics2017，10，2： | 0 |
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