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1.
N. I. Leonyuk 《Crystallography Reports》2008,53(3):511-518
The reactivity of viscous melts has been analyzed as a function of the degree of anion polymerization. Precise techniques are proposed for detecting the phase relations and kinetics of high-temperature crystallization of new materials in four-to-six-component borate and tantalate systems. For rare earth polyfunctional borates RAl3(BO3)4 (R = Y or lanthanides), efficient frequency conversion with parameters greatly exceeding the corresponding parameters for known media has been demonstrated for the first time. The conditions for fabrication of refractory optical single crystals having high thermal conductivity and other record characteristics (in comparison with the known diode-pumped lasers) for femtosecond integrated optics have been optimized. Bases of the laboratory technology of growth of such crystals are considered. 相似文献
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D. L. Sun Y. Hang L. H. Zhang G. Z. Luo S. N. Zhu P. K. Lim W. W. Hung 《Crystal Research and Technology》2004,39(6):511-515
Two kinds of near‐stoichiometric LiNbO3 crystals (SLN11 and SLN19) were grown by a flux pulling method from stoichiometric melt with addition of 11mol%K2O and 19mol%K2O, respectively. Compared with the congruent melting LiNbO3, the ultraviolet absorption edges of two crystals shift towards shorter wavelengths, and the locations of the OH‐ infrared absorption band have obvious change and the bandwidths become greatly narrower. From these experimental results, the Li2O contents are determined indirectly to be about 49.6mol% for SLN11 and 49.9mol% for SLN19, respectively. The Li2O content in SLN19 is very close to the ideal value of 50mol%. The coercive fields of two crystals were measured by the poling method at room temperature. A linear relationship between the Li2O content and the coercive field was fitted. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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USb2 single crystals were grown by three methods; I — Chemical vapour transport with iodine as transporting reagent, II — Crystallization from U Sb liquid solution, III — Crystallization from U Sb Sn liquid solution. The morphology of growth and results of X-ray topography examination of crystal surface are given. 相似文献
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S. H. Yao X. B. Hu J. Y. Wang H. Liu L. Gao X. F. Cheng X. Yin X. F. Chen 《Crystal Research and Technology》2007,42(2):114-118
A near stoichiometric LiNbO3 single crystal has been grown by the Czochralski method from a 58.5% Li melt hold in a large platinum crucible. High resolution X‐ray rocking curves of 30 0 and 0006 reflections indicated that the near stoichiometric LiNbO3 crystal possesses the high structural quality. Compared with the congruent LiNbO3, the near stoichiometric LiNbO3 possesses shorter ultraviolet absorption edge, thus higher Li concentration. The OH– infrared absorption band analyses showed that the Li concentration in the near stoichiometric LiNbO3 crystal is higher than that in the congruent LiNbO3 crystal. This result is in good agreement with that of the ultraviolet absorption edge. The electro‐optic (EO) coefficient γ22 of the near stoichiometric LiNbO3 crystal was measured to be 6.75 pm/V higher than that of congruent LiNbO3 crystal. It also proves the near stoichiometric LiNbO3 electro‐optic Q‐switched requires a low driving voltage and it is advantageous for the device performance. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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The growth of single crystals of potassium chloride (KCl) in silica gels upto 3 × 3 × 3 mm3 in size is described. To crystallize KCl incorporated in the gel, hydrochloric acid has been used to crystallize the KCl in the gel media. The crystalline perfection has been studied by the chemical etch pit technique. 相似文献
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O. Ye. Zhbankov I. D. Olekseyuk O. M. Yurchenko V. Z. Pankevich 《Crystal Research and Technology》2006,41(9):843-847
The phase diagrams of the CuInS2‐Sb2S3 and CuInS2‐Bi2S3 systems were investigated using X‐ray powder diffraction and differential thermal analysis. Based on these results, the compositions for the growth of the CuInS2 single crystals from CuInS2‐Sb2S3 and CuInS2‐Bi2S3 melts were selected and Bridgman crystal growth process was performed. The investigation of the obtained single crystals using X‐ray powder diffraction and optical absorption spectra indicates that the incorporation of the solvent atoms into the crystal lattice is absent. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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K. A. Kokh Yu. M. Andreev V. A. Svetlichnyi G. V. Lanskii A. E. Kokh 《Crystal Research and Technology》2011,46(4):327-330
The paper describes principal manipulations to prepare single crystals of GaSe and GaS. A new simple method of synthesis with single‐zone heating furnace is proposed. Growth of crystals was performed by modified Bridgman method with the use of rotating heat field. Raman and optical depth spectra show high structural and optical quality of obtained crystals. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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The results of a preliminary investigation of the growth and morphology of p-terphenyl crystals grown by sublimation and by solvent evaporation methods are reported. It was observed that lozenge–shaped (001) crystal plates are obtained from xylene and benzene solution while dendritic crystals by sublimation. Crystallographic orientation of the plates and microscopic observations of as-grown crystal surfaces are also described. 相似文献
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The growing of large single crystals of stearic acid (CH3(CH2)16COOH), one of the saturated fatty acids, from organic solutions is reported. There are two parts in this experimental investigation; (1) to clarify the relationship between polymorphism of stearic acid having three modifications, namely, the A-form (orthorhombic), the B- and C-forms (monoclinic) and the growth conditions in the case of solution growth, because this complicated relationship has apparently made it very difficult to obtain large single crystals, (2) to produce large single crystals of stearic acid under the optimum growth conditions according to part (1). As a result large single crystals of stearic acid more than 8 × 8 mm2 in area of the B- and C-modifications were successfully obtained. The values of long spacing, the crystal habit and the cleavage plane are also reported. 相似文献
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A review is given to show the development of growth techniques for single crystals for the incongruently melting yttrium iron garnet. As a result of this world-wide development a technique is described in some detail which allows well controlled nucleation and growth using a high temperature solution. 相似文献
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G. N. Kozhemyakin D. V. Lutskiy M. A. Rom P. V. Mateychenko 《Crystallography Reports》2008,53(7):1267-1271
The growth conditions and structural quality of Sb-Bi gradient single crystals with Bi content from 2 to 18 at %, grown by
the Czochralski method with solid phase feed, are investigated. Bi distribution in the crystals along their pulling direction
are studied by electron probe microanalysis and the change in the interplanar spacing is analyzed by double-crystal X-ray
diffraction. It is established that the pulling rate and feed mass affect the Bi distribution in Sb-Bi single crystals. 相似文献
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Potassium bismuth tungstate [KBi(WO4)2] single crystals with dimensions up to 20 mm × 15 mm × 15 mm have been successfully grown by using the top‐seeded solution growth technique and K2W2O7 as solvent. Experiments show that this crystal is unstable in a strong acid or alkali environment and has a blue fluorescence emission. The density, hardness, melting point, absorption edge, transparency range, prominent Raman shift frequency are 7.57 g/cm3, 238 kg/mm2, 800 °C, 380 nm, 400–5450 nm, 868 cm–1 respectively. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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Optically clear single crystals of Na3Sb2F9 have been grown from solution by slow evaporation technique at constant temperature. Crystals of sizes upto 30 × 8 × 8 mm have been grown in a period of three months. Vickers microhardness measurements have been carried out on these crystals. Attempts have also been made to understand the nature of the cracks developed around the microindentation. Single crystal X-ray diffraction studies have been carried out and cell parameters are determined. 相似文献
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A Single crystal of FeTi with a diameter of ca 34 mm and a length of ca 48 mm has been grown from a quasi-stoichiometric melt with an excess of 1% titanium employing the Bridgman technique. Experiments with the Czochralski technique were not successful. The only crucible material sufficiently resistent against reaction with the melt is electrographite. Elastic and thermoelastic constants were determined by means of ultrasonic methods. FeTi and α iron possess a similar bulk compressibility, thermal expansion, and thermoelastic constants. The longitudinal elastic resistance c11 of FeTi supersedes that of α iron by an amount of ca 30%. 相似文献
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Guodong Zhang Xutang Tao Huapeng Ruan Shanpeng Wang Qiong Shi 《Journal of Crystal Growth》2012,340(1):197-201
Using a high purity CdSiP2 polycrystalline charge synthesized in a single-temperature zone furnace, a CdSiP2 single crystal with dimensions of 8 mm in diameter and 40 mm in length was successfully grown by the vertical Bridgman method. The quality of the crystal was characterized by high resolution X-ray diffraction and the full width at half maximum (FWHM) of the rocking curve for the (200) face is 33″. Thermal property measurements show that: the mean specific heat of CdSiP2 between 300 and 773 K is 0.476 J g?1 K?1; the thermal conductivity of the crystal along the a- and c-axes is 13.6 W m?1 K?1 and 13.7 W m?1 K?1 at 295 K, respectively; and the thermal expansion coefficient measured along the a- and c-axes is 8.4×10?6 K?1 and ?2.4×10?6 K?1, respectively. The optical transparency range of the crystal is 578–10,000 nm, and there is no absorption loss in the spectrum from 0.7 to 2.5 μm, as often exists with ZnGeP2 crystals grown from the melt. 相似文献
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S. Krishnan C. Justin Raj R. Robert A. Ramanand S. Jerome Das 《Crystal Research and Technology》2007,42(11):1087-1090
Single crystals of ferroelectric succinic acid were grown from aqueous solution by low temperature solution growth technique. The cell parameters and space group are found using powder X‐ray diffraction analysis. The presence of the functional groups has been estimated qualitatively by FTIR analysis. The UV‐Visible spectrum shows the cut‐off wavelength at 240 nm. The thermal stability of the crystal was studied by TG/DTA. The dielectric constant of the crystal studied as a function of frequency shows the pyroelectric property. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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Single crystals of the HgGaInS4 layered compound were grown by the iodine transport technique. Results of their optical, photoelectric, and radiative properties' study are presented. The band gap and the binding energy of holes on the sensitizing centres were determined to be Eg = 2.41 eV and Ea = 0.2 eV, respectively. A presence of quasi-continuously distributed states was stated which are responsible for the exponential segment of the absorption edge and which take part in the radiative recombination. 相似文献