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The relation between the growth shapes and supersaturations and/or supercoolings was investigated in the Na2S2O3 5H2O crystals: (i) The growth shapes changed from a hexagonal prismatic crystal, aggregate of platy crystals and to a spherulite with an increase of supersaturations and/or supercooloings. (ii) The deposition rate suddenly increased at a certain supersaturation and/or supercooling, where the growth shape changed from the hexagonal prism to the aggregate of platy crystals. (iii) The deposition rates of spherulites become higher with increasing the solute concentrations. (iv) The formation process of the spherulites were in situ observed by the Schlieren and/or Mach‐zehnder interferometer methods. 相似文献
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采用自发成核方法,以NaCl-Na2CO3为助熔剂,生长了毫米级的NaCo2O4晶体。通过X射线衍射对晶体作了表征。利用扫描电子显微镜和原子力显微镜研究了晶体的形貌和生长机理。结果表明:所得晶体是NaCo2O4,属于六方晶系,晶胞参数:a=b=0.2842 nm,c=1.0894 nm,V=0.0761997 nm3。NaCo2O4晶体是沿c轴层状生长的,同时从阴离子配位多面体的角度分析了晶体的形貌。 相似文献
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K. Joo J. Paitz D. Klimm P. Reiche K.H. Auh W. Schrder 《Crystal Research and Technology》2000,35(4):493-499
Barium cerate crystals of 1.5 mm diameter could be grown from melt solutions containing barium chloride, barium oxide (from thermolysis of barium carbonate), and cerium(IV) oxide. The maximum size of the crystals is limited by the low solubility of cerium(IV) oxide in the barium chloride melt (ca. 0.1 Mol%). The flux can be removed by leaching the melt with water. Acid solutions must not be used to avoid decomposition of the barium cerate crystals. Neither congruent melting or incongruent decomposition of the BaCeO3 crystals could be found up to 1580 degrees centigrade. 相似文献
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Na5[B2P3O13]晶体双晶结构的研究 总被引:1,自引:0,他引:1
采用泡生法和b向籽晶生长出尺寸为22mm×24mm×20mm的透明Na5[B2P3O13]晶体.晶体定向中发现(100)和(001)晶面的一级衍射出现双峰;正交偏光显微镜下观察晶体的(010)切片,看到清晰的明暗条纹;当一束激光正入射(010)切片时,产生衍射现象;用同步辐射白光X射线形貌术拍摄了(100)、(010)和(001)切片的Laue像,观察到了晶体的孪晶结构,再借助(010)切片的化学腐蚀研究,推出该晶体为规则的聚片双晶,其结合面为(001). 相似文献
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Hiroaki Takeda Reinhard Uecker Makoto Kumatoriya Kiyoshi Shimamura Peter Reiche Tsuguo Fukuda 《Crystal Research and Technology》1997,32(7):939-945
Transparent, crack-free Na2CaGe6O14 (NCG) single crystals were successfully grown using the Czcchralski technique. The largest crystal had 30 mm in total length and 18 mm in maximal diameter. Best crystal quality was achieved under low temperature gradient arrangement. The crystal structure of NCG has been refined from single crystal X-ray diffraction data. Some piezoelectric properties of NCG are reported. 相似文献
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β-BaB2O4 (BBO) crystals with well-defined morphology have been grown from Na2O solutions using the top seeded solution growth (TSSG) method. The crystal morphology in relation to its structure and growth conditions has been studied in detail on the basis of crystallography and crystal chemistry. It is found that the morphological characteristics are related to the orientations of structural unit (B3O6)3— anion rings in the crystal. On the other hand, the growth parameters may greatly affect the appearance of faces of the crystal, but the crystals still generally take trigonal in outline and have a diagnostic character of point group 3m. The observed morphology is in disagreement with BFDH and PBC analyses and is explained from the incorporation of the growth units on the faces and facets. Since the incorporation rates of the growth units are different on different faces, the boule habits with well-defined morphology are formed. 相似文献
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采用改进的坩埚下降法生长出φ1.5"×1.5"的无宏观缺陷的溴化铈晶体毛坯.研究测试了溴化铈晶体的荧光光谱、紫外-可见透射光谱及光输出、能量分辨率、本底等闪烁性能.结果表明:在光致激发下,溴化铈晶体的发光主峰位于390 nm;其10 mm厚度样品在390nm处的光透过率为60;;φ1"×1"大小的样品在137Cs源的662 keV伽马射线作用下能量分辨率为4.26;,光输出相当于NaI(Tl)晶体的125;;溴化铈晶体中在0.005 Bq/g探测限下未检测到138La和227Ac元素,本底水平显著低于掺铈溴化镧晶体. 相似文献
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Large single crystal of BeO · 3 Al2O3 (beryllium hexa-aluminate or BHA) doped with chromium up to 20 mm in maximum diameter and 60 mm long were grown by Czochralski method. Thechnological conditions of crystal growth have been introduced and key factor leading to a successful growth is a adequate composition of starting charge mixture other than stoichiometry. The crystal structure, absorption spectra and fluorescence spectra of BHA: Cr3+ have been measured. Vibronic side band of the fluorescence spectra is from 700 nm to 900 nm. 相似文献
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The morphology of potassium dichromate (KBC) crystals grown under different conditions by solvent evaporation method is investigated. Observations of the examination of asgrown surfaces and inclusions, and of the realtion between dislocations and inclusions are presented. The results indicate that the change in the morphology of KBC crystals can be associated with the dislocation structure in the crystal. 相似文献
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La3Ga5SiO14单晶的生长、性能及SAW应用 总被引:4,自引:8,他引:4
本文综述了新型压电晶体La3Ga5SiO14的最新研究进展,详细讨论了该晶体的生长问题,简单介绍了该晶体的性能及其在SAW和BAW方面的应用,分析了该晶体在压电应用方面的优势. 相似文献
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C. S. Fang H. S. Zhuo Z. H. Yang L. Fang J. N. Sherwood 《Crystal Research and Technology》1995,30(5):599-602
Potassium lanthanum nitrate dihydrate (KLN) is a new nonlinear optical crystal. An Nd-doped potassium lanthanum nitrate (KLNN), was grown. As the first on this crystal and its characters of growth, thermal, spectral, and nonlinear optic properties is reported. KLNN crystal will be a useful material in frequency conversion of generating blue-green laser. 相似文献
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Large single crystals of the non‐centrosymmetric hydrated tetraborates Na2[B4O5(OH)4] . 3H2O (Tincalconite) (point group 32) and K2[B4O5(OH)4] . 2H2O(point group 222) were grown from aqueous solutions and the linear optical properties (refractive indices between 365 nm and 1530 nm and unpolarized absorption spectra) as a basis for nonlinear optical investigations were determined. The uniaxial positive sodium salt is not phase matchable; in the orthorhombic potassium compound type I phase matching is possible in the near infrared region. Thermal investigations indicate a phase transition at ≈285 K for Na2[B4O5(OH)4] . 3H2O. 相似文献
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Abstract [Na(H2O)2(C18H15O6SO3)]2 was synthesized by sulfated 5-hydroxy-6,7,4′-trimethoxyisoflavone with concentrated sulfuric acid. Single-crystal X-ray diffraction
study indicates that it is a dimeric centrosymmetric species. The coordination polyhedron of each Na(I) atom exhibits a distorted
trigonal bipyramidal geometry. The dimeric units are linked by intermolecular hydrogen bonds C–H⋯π, C–H⋯O and O–H⋯O to result
in a three-dimensional framework.
Graphical Abstract [Na(H2O)2(C18H15O6SO3)]2 was synthesized by sulfated 5-hydroxy-6,7,4′-trimethoxyisoflavone with concentrated sulfuric acid. The coordination polyhedron
of each Na(I) atom exhibits a distorted trigonal bipyramidal geometry. The dimeric centrosymmetric units are linked by intermolecular
hydrogen bonds C–H⋯π, C–H⋯O and O–H⋯O to result in a three-dimensional framework.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
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Pure BSO and Ce, Nd, Eu, Cr and Fe doped BSO crystals of high optical quality with 20x20x100mm3 have been grown by the vertical Bridgman method. After measuring their transmission spectra, light outputs, FWHM energy resolutions and excitation-emission spectra, we summarized and explained the laws of doped effects on the scintillation characteristics. we can expect that Eu may be the most promising dopant candidate of the doped elements for improving the scintillation characteristics of BSO crystal. 相似文献