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TeO2-Nb2O5系统玻璃的成玻性能研究 总被引:2,自引:0,他引:2
TeO2是一种线性和非线性光学性能优良、但无法单独形成玻璃的重金属氧化物玻璃系统,Nb2O5的引入有利于获得均匀而稳定的碲酸盐系统玻璃.研究发现,Nb2O5的引入会改变TeO2-Nb2O5系统玻璃中Te4 、Nb5 的配位数,进而对玻璃的结构和成玻能力、稳定性以及析晶性能均产生明显的影响.含有20-30wt%Nb2O5的碲酸盐系统玻璃表现出较好的综合品质. 相似文献
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AgCl纳米晶掺杂铌碲酸盐系统非线性光学玻璃材料研究 总被引:4,自引:0,他引:4
铌碲酸盐非线性光学玻璃具有优良的三阶非线性光学效应,引入适量纳米晶体后,有望进一步提高玻璃的三阶非线性光学性能.本文采用在辅助电场诱导下的热处理方法在TeO2-Nb2O5-BaO-AgCl系统玻璃中析出AgCl纳米晶体,并研究了AgCl含量、热处理工艺及电场施加工艺对纳米晶析出和三阶非线性光学性能的影响.结果发现,在铌碲酸盐系统玻璃中引入0.1%~0.35%(质量分数)的AgCl,经热处理后可在玻璃中获得AgCl纳米晶体,而辅助电场提供的较小推动力可诱导更多的纳米晶体均匀析出,并且可以将其尺寸控制在20nm以下.采用辅助电场与热处理工艺相匹配的控制技术可以明显提高材料的三阶非线性光学性能. 相似文献
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TeO2对氟铝酸盐玻璃性质和结构的影响 总被引:1,自引:0,他引:1
以10MgF2—20CaF2—10SrF2—10BaF2—15YF3—35AlF3氟铝酸盐玻璃为基玻璃引入不同含量的TeO2得到了新的氟碲铝酸盐玻璃.用差热分析方法研究了TeO2对氟铝酸盐玻璃性能的影响,通过拉曼光谱和红外吸收谱来研究玻璃的结构变化.差热分析表明TeO2的增加使玻璃开始析晶温度瓦升高,融化温度%降低,成玻璃能力增加.玻璃结构分析表明氟碲铝酸盐玻璃的结构中存在[FnAl-O—AlFn]、[TeO3]、[TeO2F]和[TeOF2]等多面体,这些多面体由F^-和O^2-离子连接.这种新的氟碲铝酸盐玻璃有着良好的成玻璃能力,在0.75~5.00μm范围内玻璃具有很高的透过率,是一种具有应用前景的新的红外光学玻璃材料. 相似文献
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用传统熔融法制备了一种新型的氧卤碲酸盐玻璃:(80-x)TeO2-10Nb2O5-10BaCl2-xAlF3(x=10、20和30),用密度比重天平、玻璃热膨胀仪、棱镜耦合仪、显微拉曼光谱仪和红外-可见-紫外分光光度计研究了组分变化对物理性能、结构及光学性质的影响。研究结果表明,随着玻璃中AlF3含量增加,玻璃的密度和折射率减小;在Tg温度前,玻璃的平均线膨胀系数α减小;玻璃的热稳定性增强;玻璃结构中的双三角锥体[TeO4]和变形的双三角锥体[TeO3+1]以及三角棱锥体[TeO3]相对含量都相应减少;玻璃在紫外吸收边出现了蓝移现象,玻璃的直接和间接光学帯隙都增大。 相似文献
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掺铒TeO2-Nb2O5-ZnO系统玻璃的上转换发光性能 总被引:1,自引:0,他引:1
稀土离子掺杂碲酸盐系统玻璃是一类应用前景良好的上转换发光材料.研究了含铒TeO2-Nb2O5-ZnO系统玻璃在980nm抽运下的上转换光谱,结果发现存在3个上转换荧光谱带,分别对应于2H11/2→4I15/2、4S3/2→4I15/2和4F9/2→4I15/2,而且Er3 含量的增加可明显提高材料在530、550和660nm附近的发光性能.少量的ZnO引入既可以大幅提升材料的上转换发光强度,又能保持铌碲酸盐玻璃良好的化学稳定性.材料的发光机制主要是激发态吸收(ESA)和能量转移(ET),最大声子能量的降低是上转换发光增强的主要原因. 相似文献
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TeO2-ZnCl2-BaO-NaF玻璃系统的结构及中红外透过特性的研究 总被引:3,自引:0,他引:3
制备了一种新型的氧卤碲酸盐玻璃:(80-x)TeO2—15ZnCl2-xBaO-5NaF(x=30、20、10、0mol%),对玻璃的机械强度、热稳定性、拉曼光谱、紫外吸收光谱、红外透过光谱等特性进行了研究.通过拉曼光谱分析研究了玻璃组分含量的变化对玻璃结构和红外透过性能的影响.结果表明,随着BaO含量的增加,玻璃在红外波段透过率显著增加,并且红外透过截止波长向长波方向移动,本文对这一实验结果进行了机理性的研究探讨.同时,通过在熔制过程中通入高纯O2,以及引入适量的卤化物有效地除去玻璃中的[OH]基团,使玻璃的红外透过性能得到进一步的提高.这种新型的氧卤碲酸盐玻璃在中红外区域有较高的透过(≥80%),中红外波段透过截止波长达6.5μm,是一种红外透过性能优良的光学玻璃材料. 相似文献
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Knowledge about vapour-liquid (VLE) is required as a basis of reliable calculations for separation processes. Correlations available for the prediction of T, p, x, y data are less accurate for mixtures at high pressures and mixtures containing supercritical components. The results of VLE experiments are reported and compared with data calculated with equations of state. 相似文献
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We prepared weakly agglomerated powders of ZrO2-CeO2 and HfO2-CeO2 solid solutions 5–8 nm in particle size, consisting of monoclinic and tetragonal phases. After heat treatment at 1200°C, the crystallite size was 30 and 14 nm, respectively. We also examined the effect of precipitate freeze drying on the crystallization of hafnia-based solid solutions containing up to 20 mol % CeO2. 相似文献
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Thermal diffusion coefficients were measured in two gaseous mixtures, in which one component was close to the critical temperature, in the pressure range (19.6–127.4)·104 N/m2 and at a freon concentration of 0.25–0.8. 相似文献
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C. Bersier E. P. Stoll P. F. Meier T. A. Claxton 《Journal of Superconductivity and Novel Magnetism》2002,15(5):399-402
First-principles cluster calculations are reported of the local electronic structure of the three compounds: La2CuO4, Sr2CuO2Cl2, and Sr2CuO2F2. The copper ${\text{3d}}_{x^2 - y^2 } $ and the planar oxygen 2p σ atomic orbitals exhibit a similar degree of covalency. The out-of-plane orbitals, however, are quite different with the ${\text{3}}d_{3z^2 - r^2 } $ atomic orbital lowered significantly in energy for chlorine and fluorine apical positions. 相似文献
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A series of GRIN glass rods have been developed in Li2O-Na2O-Al2O3-TiO2-SiO2 systems. Negative radial refractive index profiles were generated by exchanging Na+ for Li+ ions in these glass rods. It has been observed that TiO2 plays a vital role in increase in the profile depth and maximum change in the refractive index because of its ambivalent nature. Change in the refractive index can be further increased by increasing the concentration of exchanging cation in the base glass. 相似文献
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V Vijayashree C K Subramaniam R Srinivasan I K Gopalakrishnan PVPSS Sastry J V Yakhmi R M Iyer 《Bulletin of Materials Science》1991,14(3):827-830
Single-phase 2122 samples of thallium and bismuth superconductors were made by the precursor matrix method. The thermopower
of these samples was measured in the temperature range 250 K-T
c
. The thermopower was positive and decreased linearly with increasing temperature aboveT
c
(onset). The exponential enhancement of thermopower seen in the undoped and doped YBCO was not observed in these samples.
The linear variation of thermopower can be explained on the basis of either a two-band model or a narrow band model. 相似文献
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本文给出了 Si_2N_2O-Al_2O_3-La_2O_3和 Si_2N_2O-Al_2O_3-CaO 系统的亚固相图。实验结果表明:在 Si_2N_2O-Al_2O_3-CaO 系统中有一个未知结构的新化合物 CaO·Si_2N_2O,在3CaO·Si_2N_2O 和3CaO·Al_2O_3两化合物之间形成连续立方固溶体。而 Si_2N_2O-Al_2O_3-La_2O_3系统中则没有发现新化合物。在两个系统的富 Si_2N_2O区,过量的 Si_2N_2O 与 La_2O_3和 CaO 分别反应形成 Si_3N_4与 La_(10)[SiO_4]_(?)N_2(H-相)(和 CaSiO_3。所研究的这两个三元系统中,分别形成了如下几个四元相容性区。在 Si_2N_2O-Al_2O_3-La_2O_3系统内有:H-Si_3N_4-La_2O_3·Si_2N_2O-La_2O_3·Al_2O_3;H-Si_3N_4-La_2O_3·Al_2O_3-La_2O_3·11 Al_2O_3;H-Si_3N_4-La_2O_3·11 Al_2O_3-Al_2O_3;H-Si_3N_4-Al_2O_3-O′s.s;H-Si_3N_4-O′s.s-Si_2N_2O在 Si_2N_2O-Al_2O_3-CaO 系统内有:Si_3N_4-CaSiO_3-CaO·Si_2N_2O-3CaO·Al_2O_3;Si_3N_3-CaSiO_3-3CaO·Al_2O_3-2CaO·Al_2O_3·SiO_(?);Si_(?)N_(?)-CaSiO_3-2CaO·Al_2O_3·SiO_2-Al_2O_3;Si_3N_4-CaSiO_3-Al_2O_(?)-O′s.s;Si_3N_4-CaSiO_3-O′s.s-Si_(?)N_(?)O 相似文献
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I. R. Shein S. L. Skornyakov V. I. Anisimov A. L. Ivanovskii 《Journal of Superconductivity and Novel Magnetism》2014,27(1):155-161
The first-principles calculations were performed to predict the elastic and electronic properties of the superconducting ThCr2Si2-type phases CaPd2As2 and SrPd2As2 in comparison with the non-superconducting CeMg2Si2-type phase BaPd2As2. Besides, the same properties were compared for CeMg2Si2- and ThCr2Si2-type polymorphs of BaPd2As2. We found that all these phases are mechanically stable and belong to soft materials with low hardness. The near-Fermi region is formed by the valence states of the blocks [Pd2As2] with decisive contributions of Pd 4d states. The values of N(E F) increase in the sequence: CaPd2As2 < SrPd2As2 < BaPd2As2, i.e. in the reverse sequence relative to the transition temperatures T C. Thus, the change in T C cannot be explained by the electronic factor, i.e. by the simple correlation T C~N(E F). Most likely the decrease in T C in the sequence CaPd2As2 → SrPd2As2 and the absence of a superconducting transition in BaPd2As2 are related to the structural factors and the peculiarities of the electron–phonon coupling mechanism. 相似文献