提拉法生长钽酸钾晶体

用提拉法生长出了一系列钽酸钾(KTaO3)晶体,其中最大可达31 mm×31 mm×40 mm,质量为247g.X射线粉末衍射仪测试结果表明:KTaO3单晶具有立方结构,晶胞参数a=0.398 88 nm.透射光谱显示:KTaO3单晶在340～3 500 nm的波长范围内有宽广的透光波段,仅在2 875 nm的处有吸收峰.讨论了KTaO3晶体的表面形貌、宏观缺陷及生长习性.     

提拉法生长立方相KTa1-xNbxO3晶体

报道了用提拉法在KNbO3-KTaO3固熔体体系中生长立方相KTa10xNbxO3晶体。实验采用两种不同的原始配料生长晶体：即生长组分分别为KNbO3：KTaO3（摩尔分数）=0．35：0．65和0．45：0．55，分别得到x=0．14和0．19的KTN晶体，晶体尺寸可达厘米级。分析了晶体的形态特征和宏观缺陷并讨论了各种缺陷的形成机制；利用JXA-8800电子探针技术测定了晶体组分；讨论了影响晶体生长的多种条件。发现温场和提拉速度是影响KTN晶体生长和质量的主要因素。     

Growth and characterization of ferroelectric Tb2（MoO4）3 crystal

By using Zb4O7 and MoO4 as starting materials, ferroelectric Tb2(MoO4)3 crystal was grown by the Czochralski method. The as-grown crystal was pale green color, transparent and crack-free. X-ray powder diffraction (XRPD), transmission spectrum, dielectric con-stant and polarization-electric field (P-E) hysteresis loop measurements were performed to characterize the crystal. The XRPD confirmed the as-grown crystal to be Tb2(MoO4)3. The transmission spectrum of the crystal showed that its transmittance in the entire visible and most near-infrared region was more than 70% except for an absorption peak around 486 nm. Obvious dielectric anomaly could be observed at low frequencies with increasing temperature through the dielectric constant measurement and the Curie temperature of Tb2(MoO4)3 crystal was determined to be 162.3℃. The unsaturated P-E hysteresis loops indicated that it was difficult for the ferroelectric domains in Tb2(MoO4)3 crystal to array regularly with repeated switching of the electric field.     

Nd:Lu0.5Gd0.5VO4被动调Q激光中的能量增强效应

介绍Nd:Lu05Gd0.5VO4混晶的被动调Q激光特性.与Nd:GdVO4调Q激光相比较,发现Nd:Lu0.5Gd0.5VO4具有明显的能量增强效应.     

高层建筑超厚底板大体积混凝土施工技术分析

主要研究高层建筑超厚底板大体积混凝土施工技术,对高层建筑超厚底板大体积混凝土的显著特征进行了研究,并对其施工准备、钢筋绑扎、模板拆装、砼浇筑、养护等关键技术环节进行了研究。为了保证底板大体积混凝土的施工质量,需要重视配合比的设计、浇筑振捣质量、人模温度和养护温度等问题。     

钕离子掺杂硅酸镓钙铌晶体的生长和激光性能研究

Nd³⁺离子由于其独特的能级结构，在近红外激光应用方面受到了广泛关注。硅酸镓钙铌(CNGS)晶体作为硅酸镓镧体系的一员，具有较好的力学性能和热学性能。使用提拉法生长了Nd³⁺掺杂的CNGS晶体，直径为30 mm，等径部分长度为45 mm，并对其折射率、吸收光谱、发射光谱等光学性能进行了表征。使用880 nm泵浦光，沿b向获得了1065 nm的激光输出，泵浦功率为6.69 W时激光输出功率为1.88 W，转换效率为28.1%。