共查询到20条相似文献，搜索用时 15 毫秒
1.
Petr Ershov Sergey Kuznetsov Irina Snigireva Vyacheslav Yunkin Alexander Goikhman Anatoly Snigirev 《Journal of Applied Crystallography》2013,46(5):1475-1480
X‐ray refractive lenses are proposed as a Fourier transformer for high‐resolution X‐ray crystal diffraction. By employing refractive lenses the wave transmitted through the object converts into a spatial intensity distribution at its back focal plane according to the Fourier‐transform relations. A theoretical consideration of the Fourier‐transform technique is presented. Two types of samples were studied in Bragg reflection geometry: a grating made of strips of a thin SiO2 film on an Si substrate and a grating made by profiling an Si crystal. Fourier patterns recorded at different angles along the rocking curves of the Si 111 Bragg reflection were analysed. 相似文献
2.
X. Q. Wang D. Xu Q. Ren G. H. Zhang X. B. Sun X. Q. Hou W. F. Guo H. Lü 《Crystal Research and Technology》2007,42(4):349-355
The preparation and single crystal growth of bis(tetrabutylammonium)bis(4,5‐dithiolato‐1,3‐dithiole‐2‐thione)copper, (I), are described. The energy gap Eg of (I) is about 2.38 eV. The nonlinear optical susceptibility χ(3) is about 1.3×10‐3 esu at 1064 nm. The characterization of (I) has been performed by electronic absorption, infrared and X‐ray powder diffraction spectroscopy. The thermal behavior of (I) has been investigated by means of thermogravimetric analysis (TGA) and differential thermal analysis (DTA) measurements in air. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
3.
M. M. Wu Y. Zu J. Peng R. D. Liu Z. B. Hu Y. T. Liu D. F. Chen 《Crystal Research and Technology》2012,47(7):793-798
Solid solutions In2 − xCrxMo3O12 have been prepared via the solid state reaction method. The structural and thermal expansion properties have been characterized using X‐ray diffraction. All compounds exhibit monoclinic structure with space group P21/a at room temperature, and transform to orthorhombic structure at higher temperature. Compounds In2 − xCrxMo3O12 (x = 0.7, 1.0 and 1.3) possess strong positive thermal expansion in the monoclinic structure, while their thermal expansion coefficients of orthorhombic structure vary from negative to positive with increasing Cr content. It is worthwhile to note that In1.3Cr0.7Mo3O12 and InCrMo3O12 have near zero thermal expansion properties. 相似文献
4.
T. I. Milenov P. M. Rafailov M. V. Abrashev R. P. Nikolova R. Titorenkova M. M. Gospodinov 《Crystal Research and Technology》2009,44(11):1192-1196
Large crystals of La0.63Pb0.37Mn O3+δ with small La(Pb)‐ deficiency of about 0.005‐0.01 at.% were grown by high temperature solution growth method. The structure of the grown crystals was determined as rhombohedral with R‐3 space group by single‐crystal X‐ray diffractometry. The surface morphology of the crystals and the exact chemical composition was examined by scanning electron microscopy and energy dispersive X‐ray analysis methods, respectively. The IR‐transmission spectrum reveals the presence of Mn3+O6‐ and Mn4+O6‐ octahedra in the lattice of La0.63Pb0.37Mn O3+δ crystals. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
5.
《Crystal Research and Technology》2018,53(4)
High‐end nonlinear optical devices demand superior quality KH2PO4 crystal and to meet this necessity slow solvent evaporation technique is employed to grow optical quality potassium dihydrogen orthophosphate (KH2PO4, KDOP) crystal by doping tartaric acid (TA) and special attention is devoted to optimize the defect influenced properties of KDOP crystal. The incorporation of TA in KDOP crystal matrix is evaluated by employing energy dispersive spectroscopic technique. The crystalline phase and structural dimensions of pure and TA doped KDOP crystal is evaluated by means of powder X‐ray diffraction analysis. The luminescence behavior of TA doped KDOP crystal is examined in visible region and violet colored emission is evidenced at 408 nm. The Vickers microhardness studies are carried out to uncover the constructive influence of TA on hardness and elastic stiffness coefficient of KDOP crystal. Impressive role of TA in minimizing defect density and improving the surface growth mechanism of KDOP crystal is explored by chemical etching analysis. The thermogravimetric analysis curve is traced within 30–650 °C and TA doped KDOP crystal is found thermally stale up to 233 °C. The results are appraised to propose the suitability of TA doped KDOP crystal for distinct applications. 相似文献
6.
Tapati Mallik Tanusree Kar Gabriele Bocelli Amos Musatti 《Crystal Research and Technology》2006,41(3):280-284
Crystal structure and thermal stability of the hydrated crystals of the basic amino acid L‐arginine named as L‐arginine dihydrate (LAD), a nonlinear optical material have been reported here. The title compound crystallized in the space group P212121 with Z=4 and unit cell dimensions a=11.856(2)Å, b=15.694(2)Å, c=5.664(3)Å. The arginine molecule is a zwitterion with the guanidyl group accepting an extra proton from the carboxylate group. DTA‐TG analysis gives an idea about the thermal behaviour of LAD and ruled out the possibility of structural changes independent of mass changes. © 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim 相似文献
7.
V. Sagredo L. Betancourt L. M. de Chalbaud G. E. Delgado 《Crystal Research and Technology》2004,39(10):873-876
Single‐crystal of the CdGaCrSe(4‐X)S(X) system (x = 0; 1; 2; 3; 4) were grown by the chemical vapour‐phase transport technique. The crystals were obtaine by using CdCl2 as transporting agent for the composition with x = 1, and CrCl3 for those with x = 0; 2; 3 and 4. X‐ray powder diffraction analysis indicated that some of the samples crystallizes in the tetragonal system with space group I‐4 (CdGaCrSe3S , x = 1; CdGaCrSe2S2 , x = 2), or in a cubic system with space group Fd‐3m (CdGaCrSeS3, x = 3; CdGaCrS4, x = 4), however the sample of CdGaCrSe4 (x = 0) crystallizes in rhombohedral system. Magnetic measurements show significant changes in the magnetic interactions behaviour probably due to the anionic substitutions. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
8.
The structural parameters, the axial thermal expansion coefficients and the characteristic Debye temperatures for the order vacancy compound CuGa5Se8 with the chalcopyrite‐related structure, prepared by the Bridgman technique, were determined at different temperatures between 90 and 650 K by the X‐ray diffraction method. The melting point of this compound was defined from the differential thermal analysis data. The anisotropy of thermal expansion in CuGa5Se8 is shown to exist with the coefficients along a ‐axis being larger than those along the c ‐axis throughout the temperature range studied. 相似文献
9.
N.S. Orlova I.V. Bodnar T.L. Kushner E.A. Kudritskaya 《Crystal Research and Technology》2002,37(6):540-550
CuIn3Se5 and CuGa3Se5 uniform single crystals 12 mm in diameter and 40 mm in length with the chalcopyrite‐related structure were prepared by directed crystallization of the melt. The melting points of these compounds were defined by means of the differential thermal analysis (DTA). The lattice parameters a and c as well as the axial thermal expansion coefficients αa and αc were determined as a function of temperature in the range from 90 to 650 K by the X‐ray diffraction method (XRD). It is found that for both the compounds the coefficients of expansion along the a ‐axis are larger than those along the c ‐axis over the entire temperature range studied. 相似文献
10.
Ricardo S. Ferreira Júnior Geanso M. Moura Andreia C. Pereira Paulo R. da Silva Ribeiro Luzeli M. da Silva Adenilson O. dos Santos 《Crystal Research and Technology》2016,51(12):738-741
Semi organic crystals have been intensively studied aiming applications in nonlinear optical (NLO). Such applicability requires crystals with both high quality and thermal stability, which make the full characterization of this material a topic issue. In this paper, single crystals of L‐isoleucine hydrochloride monohydrated (L‐Ile.H2O.HCl) was synthesized by slow evaporation technique and characterized by thermal analysis and X‐ray diffraction (XRD) measurements. XRD results at 298 K showed that the sample crystallize with the orthorhombic structure, and the lattice parameters obtained by Rietveld refinement were a = 5.873(3) Å, b = 24.814(4) Å, and c = 6.873(5) Å. Thermal analysis measurements shows four decomposition stages between 328 ‐480 K which were associated with loss of water by desolvation, loss crystallization water and decomposition of L‐Ile.HCl. XRD measurements as a function of temperature up to 428 K show an irreversible phase transformation. This transformation was obtained after 32 hours keeping the L‐Ile.HCl.H2O sample at 413 K. The analysis shows that phase transformation occurs due to water and chlorine losses without destroy the amino acid carbon chain and in the end of transformation only the precursor amino acid remains. L‐Ile.HCl.H2O present low thermal stability and the phase transformation is time and temperature dependent. 相似文献
11.
《Crystal Research and Technology》2018,53(2)
A new inorganic nonlinear optical single crystal of sodium cadmium tetra chloride (SCTC) is successfully grown from aqueous solution by the slow evaporation technique at room temperature. The crystalline nature of the grown crystal is analyzed by powder X‐ray diffraction. The lattice parameters and crystal system is confirmed by single crystal X‐ray diffraction. Optical transmission study on SCTC crystal shows high transmittance in the entire UV–Vis region. The mechanical strength of the grown crystal is estimated by Vicker's microhardness test. The second harmonic generation (SHG) efficiency of the crystal is measured by Kurtz's powder technique infers that the crystal has nonlinear optical (NLO) efficiency 1.75 times that of KDP. The variation of dielectric constant and dielectric loss as a function of log frequency at various temperature reveals that the crystal shows normal dielectric behaviour. The growth process of SCTC crystal is analysed by etching study. The features of surface of grown crystal is analysed by SEM/EDAX spectrum. The third order nonlinear optical property is investigated for the grown crystal by z – scan technique and the results indicates that SCTC crystal should be a promising material for nonlinear optical device applications. 相似文献
12.
I. V. Ogorodnyk I. V. Zatovsky V. N. Baumer N. S. Slobodyanik O. V. Shishkin 《Crystal Research and Technology》2007,42(11):1076-1081
Two potassium lanthanide zirconium orthophosphates with general composition K1.822Nd0.822Zr1.178(PO4)3 (KNdZrP) and K2LuZr(PO4)3 (KLuZrP) were prepared using the flux technique. Original synthetic procedure has been examined for the flux growth of the complex phosphates containing zirconium and lanthanide. Both compounds have been synthesized in the complex melts containing at the same time potassium phosphates and transition metal fluorides. The structures were solved from the single crystal (KNdZrP) and powder (KLuZrP) X‐ray diffraction data. Both compounds are isotypic to langbeinite mineral and crystallize in cubic system (sp. gr. P213) with the cell parameters a = 10.3228(2) and a = 10.29668(5) Å respectively. The rigid framework is built up from the isolated [MO6] octahedra and [PO4] tetrahedra interlinked via vertices. The potassium cations are located in the large closed cavities of the framework. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
13.
Huidong Xie Dezhong Shen Chengzhi Xie Xiaoqing Wang Guangqiu Shen 《Crystal Research and Technology》2006,41(10):961-966
Potassium bismuth tungstate [KBi(WO4)2] single crystals have been grown by the top‐seeded solution growth technique. Bulk crystal with dimensions up to several centimeters is obtained for the first time. Several self‐flux systems have been used for the growth from the solution and the experiments using K2W2O7 as a solvent are detailed. Powder and single crystal X‐ray diffraction of this crystal are reported. The structure refinement shows that KBi(WO4)2 crystallizes in the monoclinic space group C2/c, with a=10.837(3), b=10.586(3), c=7.622(2)Å, β=130.860(3)°, V=661.4(3)Å3, and Z=4. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
14.
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
15.
16.
Pure, stable stoichimetric nano crystalline hydroxyapatite material was crystallized by double diffusion technique at physiological conditions, temperature at 37°C and pH at 7.4. The sample was sintered at 400°C, 750°C and 1200°C with equal interval of time. They were characterized by X‐ray diffraction studies, Fourier Transformation Infra‐Red analysis, Thermogravimetric analysis, Scanning Electron Microscopic studies and Atomic Force Microscopic studies. The X‐ray analysis confirmed that the grown crystals are to be the pure form of hydroxyapatite. Infra‐red studies confirmed CO free hydroxyapatite. Thermogravimetric studies showed the thermal stability of the hydroxyapatite crystals even at 1200°C. The presence of pores in the sintered sample was traced by scanning electron microscopy. Atomic force microscopy revealed the presence of nano crystalline HAP of size 0.958 nanometer in the samples grown using this technique. At higher temperature the deagglomeration of bulk phases and agglomeration of nano phases leads to the nano crystalline HAP were observed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
17.
L‐Valinium picrate (C5H12NO2)+. (C6H2N3O7)–, a non‐linear optical material from the amino acid family which has large second harmonic generation (SHG) efficiency, was grown by slow evaporation method. Characterization of the crystals was made using single crystal X‐ray diffraction. The functional groups and the modes of vibrations were found by using the Fourier transform infrared (FTIR) spectroscopy. The second harmonic generation (SHG) conversion efficiency was investigated using the Kurtz and Perry method. The SHG conversion efficiency is 60 times higher than that of the standard KDP and 8 times higher than that of the standard Urea and the optical transparency was analyzed using UV‐visible‐NIR absorption spectrum. The structural features of the material leading to the large SHG efficiency are discussed. Microhardness and dielectric studies were also carried out. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
18.
R. J. C. Lima A. J. D. Moreno E. M. Diniz R. S. G. Ola J. M. Sasaki J. Mendes Filho P. T. C. Freire F. M. Pontes E. R. Leite E. Longo 《Crystal Research and Technology》2004,39(10):864-867
Leaves and branches of Ocimum Basilicum were dried, reduced to coarse powder and extracted in aqueous metanol and aqueous hexane. This paper discusses the X‐ray diffraction and FT‐Raman spectra measured at room temperature. The data obtained have been used to propose a general assignment of the vibrational fundamentals on the base of frequencies assigned in other related single crystals. From the results we can conclude that the crystal has a high symmetry. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
19.
Chengpeng Yao Youjin Zhang Yun Fan Maozhong Zhou Hai Wu 《Crystal Research and Technology》2015,50(7):566-573
Elliptic NdCrO3 microplates were synthesized by a simple and facile one‐step hydrothermal method of processing temperature 280 °C for 3 days. The products prepared in this paper have been characterized by X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), X‐ray fluorescence (XRF), Fourier transform infrared spectroscopy (FTIR) and field‐emission scanning electron microscopy (FESEM). The magnetic properties of the final sample are also studied. The XRD pattern indicates the pure orthorhombic phase for NdCrO3 particles, the XPS, XRF and FTIR results further demonstrate the composition and purity of the final product. A possible growth mechanism for elliptic NdCrO3 microplates is proposed. Through the investigation of magnetic properties, it can be generally concluded that the orthorhombic elliptic NdCrO3 microplates exhibit typical behaviors of magnetic transition, spin reorientation transition and magnetic exchange bias. The Néel temperature is 218 K and the spin reorientation transition temperature is 46 K. The hysteresis loop under 5 K shows that the value of exchange bias field (Hex) is 12 Oe and the shift of remanent magnetization (ΔM) is 0.008 emu/g, respectively. 相似文献
20.
V. Rajnikant V.K. Gupta V.D. Rangari S.R. Bapat R.B. Agarwal R. Gupta 《Crystal Research and Technology》2001,36(1):93-100
The crystal structure of the title compound (3 α ‐acetoxy‐urs‐12‐en‐24‐oic acid, C32H50O4) has been determined by X‐ray crystallographic techniques. The compound crystallizes into orthorhombic space group P212121 with unit cell parameters : a = 12.773(2), b=16.381(4), c=27.929(7)Å. The structure has been solved by direct methods and refined to R = 0.054 for 4930 observed reflections. The structure contains two crystallographically independent molecules in the asymmetric unit which are almost identical in geometry. Rings A, B, D and E have chair conformations while ring C assumes a sofa conformation in both the molecules. The molecules in the structure are linked together by intra‐ and intermolecular O‐H…= and C‐H…O hydrogen bonds. 相似文献