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1.
Thermal decomposition of ZnHg(SCN)4 (ZMTC) in air was investigated by means of thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The intermediates and final products of the thermal decomposition were identified by X‐ray powder diffraction at room temperature. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
2.
Kang Yun Choe 《Molecular Crystals and Liquid Crystals》2015,621(1):76-81
Novel X-type polyester 5 containing 4-(2’-carbomethoxy-2’-cyano)vinyl-6-nitroresorcinoxy group as nonlinear optical (NLO) chromophore, which constitutes parts of the polymer backbone, was prepared and characterized. Polyester 5 is soluble in common organic solvents such as N,N-dimethylformamide and acetone. Polyester 5 shows a thermal stability up to 280°C from thermogravimetric analysis with glass-transition temperature obtained from differential scanning calorimetry of near 116°C. The second harmonic generation (SHG) coefficient (d33) of poled polymer film at the 1064 nm fundamental wavelength is 4.25 × 10?9 esu. The dipole alignment exhibits a thermal stability even at 4°C higher than glass-transition temperature (Tg), and no significant SHG decay is observed below 120°C due to the partial main-chain character of polymer structure, which is acceptable for NLO device applications. 相似文献
3.
Novel X-type polyurethane 5 containing 4-(2′-carbomethoxy-2′-cyano)vinyl-6-nitroresorcinoxy groups as nonlinear optical (NLO) chromophores, which constitute part of the polymer backbone, was prepared and characterized. Polyurethane 5 is soluble in common organic solvents such as acetone and N,N-dimethylformamide. It shows thermal stabilities up to 260°C from thermogravimetric analysis with glass transition temperature obtained from differential scanning calorimetry near 108°C. The second harmonic generation (SHG) coefficient (d33) of poled polymer film at 1064 nm fundamental wavelength is 9.83 × 10?9 esu. Polymer 5 exhibits a high thermal stability even at 2°C higher than Tg, and no significant SHG decay is observed below 110°C, which is acceptable for nonlinear optical device applications. 相似文献
4.
Ji-Hyang Lee 《Molecular Crystals and Liquid Crystals》2015,621(1):82-88
A new X-type polyester (4) containing nitrophenylazonitroresorcinoxy groups as NLO chromophores, which are components of the polymer backbone was prepared. Polyester 4 is soluble in common organic solvents such as N,N-dimethylformamide and dimethylsulfoxide. It shows a thermal stability up to 280°C from thermogravimetric analysis with glass-transition temperature (Tg) obtained from differential scanning calorimetry near 120°C. The second harmonic generation (SHG) coefficient (d33) of poled polymer films at the 1064 nm fundamental wavelength is around 5.08 × 10?9 esu. The dipole alignment exhibits a thermal stability even at 5°C higher than Tg, and no SHG decay was observed below 125°C due to the partial main-chain character of polymer structure, which is acceptable for NLO device applications. 相似文献
5.
X.L. Duan D.R. Yuan X.Q. Wang X.F. Cheng Z.H. Yang S.Y. Guo H.Q. Sun D. Xu M.K. Lu 《Crystal Research and Technology》2002,37(5):446-455
Cadmium mercury thiocyanate (CdHg(SCN)4, CMTC) and its two lewis base adducts: cadmium mercury thiocyanate dimethyl‐sulphoxide (CdHg(SCN)4(H6C2OS)2, CMTD) and cadmium mercury thiocyanate glycol monomethyl ether (CdHg(SCN)4(C3H8O2), CMTG) have been discovered as nonlinear optical (NLO) crystal materials. Their structural, optical and physicochemical properties were characterized by X‐ray powder diffraction (XRPD), infrared spectroscopy, vis/UV/NIR spectra and thermal analysis. It is discovered that their transparency cutoffs lie in the UV region and CMTD crystals possess the shortest cutoff wavelength among the three crystal materials. 相似文献
6.
Differential scanning calorimetry (DSC) and X‐ray diffraction measurements have been performed on cesium sulfamate CsNH2SO3 single crystal. Two distinct endothermic peaks in the DSC curves are observed at 330 and 436 K. It is pointed out that the peak at 330 K is attributed to the structural phase transition, and the other peak at 436 K is associated with the thermal decomposition of the crystal. The structures in room‐ and high‐temperasture phases are determined, and the space group of the sample crystal is found to change from monoclinic P 21/c to orthorhombic Pnma. The structure of the room‐temperature phase consists of two different types of N‐H···O hydrogen bond, but in the high‐temperature phase there is no specific hydrogen bond between the NSO3 pseudo‐tetrahera. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
7.
The morphology, crystallinity and X‐ray diffraction of speciality heterocyclic and aromatic based polyurethane and poly(urethane–urea) elastomers synthesized via a one‐shot polymerization method were studied. The samples were chain extended by mixtures of aliphatic diols and furanic or aromatic diamine chain extenders. Small‐angle X‐ray scattering (SAXS) measurements confirmed the results obtained by differential scanning calorimetry (DSC) and revealed the presence of phases with sharp phase boundaries. The SAXS patterns are best fitted with a model that consists of liquid‐like ordered polydisperse spheres. Most of the samples were shown to be poorly crystalline, but some soft‐phase crystals do exist and these melted at about 353 K as confirmed by DSC and temperature‐dependent wide‐angle X‐ray diffraction. Annealing at 273 K did not affect the thermal stability but influenced the morphology of the samples. The effect of annealing on the samples of poly(urethane–urea) extended using diamine chain extenders was smaller than that for polyurethane samples, which indicates a much higher thermal stability of the poly(urethane–urea) samples owing to the formation of bidentate hydrogen‐bond networks across the urea groups. 相似文献
8.
C. Meneghini S. Mobilio L. Lusvarghi F. Bondioli A. M. Ferrari T. Manfredini C. Siligardi 《Journal of Applied Crystallography》2004,37(6):890-900
The structure of the Zr atomic environment in a CaO–ZrO2–SiO2 glass ceramic as a function of thermal treatments has been studied, combining X‐ray absorption spectroscopy (XAS), X‐ray diffraction (XRD) and anomalous XRD (a‐XRD) techniques. The analysis of XRD patterns demonstrates that the devitrification process proceeds through the partial segregation of Zr‐depleted phases (wollastonite‐like) and Zr‐rich phases (Zr oxides). The XAS and a‐XRD measurements at the Zr K‐edge have been exploited in order to obtain a closer insight into the atomic structure around the Zr atoms. In the as‐quenched glass the Zr atom is sixfold coordinated to O atoms in an amorphous environment rich in Ca and Si. Thermal treatment firstly (T = 1273–1323 K) causes partial segregation of Zr in the form of an oxide with a tetragonal zirconia (t‐ZrO2) crystalline structure. Raising the temperature (T = 1373 K) causes the formation of ZrO2 crystallites in the monoclinic crystallographic phase (baddeleyite, m‐ZrO2). Analysis of the XAS data shows that a considerable amount of Zr remains in an amorphous calcium silicate phase. 相似文献
9.
Tao Yan Feifei Zheng Yonggui Yu Shubin Qin Hong Liu Jiyang Wang Dehong Yu 《Journal of Applied Crystallography》2011,44(1):158-162
Lithium tantalate (LiTaO3, LT) wafers of different colors were prepared through chemical reduction of regular congruent LT wafers. Samples with different colors corresponding to different annealing temperatures were characterized by X‐ray diffraction, X‐ray photoelectron spectroscopy, and measurements of the Curie temperature and density. It was found that chemical reduction does not influence the basic LT structure. The Ta charge state change due to chemical reduction was found to be the main reason for the formation of black LT wafers. 相似文献
10.
The investigations on the formation of mixed crystals of ammonium dihydrogen orthophosphate (ADP) and potassium dihydrogen orthophosphate (KDP) i.e. potassium ammonium dihydrogen phosphate, K1‐x(NH4)xH2PO4 have been presented in this paper. Pure and mixed crystals of ADP and KDP have been grown by slow evaporation technique from the supersaturated solution at an ambient temperature 26±1 °C for ammonium concentration x in the range 0.0 ≤ x ≤ 1.0 in the case of mixed crystals. Crystal compositions were determined by flame atomic absorption spectroscopy and chemical analysis. The results of the X‐ray analysis of the grown crystals are also reported. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) were used to study the kinetic process of dehydration and the high temperature phase behaviour. DTA showed the distinct thermal events attributed to dehydration of ADP, KDP and K1‐x(NH4)xH2PO4. The results of thermal analysis and chemical analysis are consistent with each other. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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12.
Soumen Ghosh Sharmila Basu Santu Chakraborty Alok K. Mukherjee 《Journal of Applied Crystallography》2009,42(4):629-635
Structural and microstructural characterizations of eight human kidney stones (KS1–KS8) from eastern India have been carried out using IR spectroscopy, X‐ray powder diffraction, scanning electron microscopy and thermogravimetric methods. An X‐ray diffraction phase quantification revealed that three of the renal stones (KS1–KS3) were composed exclusively of calcium oxalate monohydrate (COM) and the remaining five (KS4–KS8) contained varying amounts of calcium oxalate dihydrate (40.1–53.0 wt%) and hydroxyapatite (1.3–17.3 wt%), in addition to the COM phase. The crystalline structure of COM (whewellite) at the atomic scale was redetermined through an X‐ray powder diffraction study at room temperature using Rietveld analysis. Thermogravimetric analysis of KS1 reveals that COM (whewellite) is stable up to around 439 K, above which temperature anhydrous calcium oxalate is formed. The oxalate transforms to calcium carbonate at 751 K and finally to calcium oxide above 969 K. It should be emphasized that meaningful statistics in total number or gender specificity cannot be achieved with eight kidney stones. 相似文献
13.
D. V. Irzhak M. A. Knyasev V. I. Punegov D. V. Roshchupkin 《Journal of Applied Crystallography》2015,48(4):1159-1164
The diffraction properties of phase gratings with the period D = 1.6, 1.0 and 0.5 µm fabricated on an Si(111) crystal by e‐beam lithography were studied by triple‐axis X‐ray diffraction. A 100 nm‐thick tungsten layer was used as a phase‐shift layer. It is shown that the presence of a grating as a phase‐shift W layer on the surface of the Si(111) crystal causes the formation of a complicated two‐dimensional diffraction pattern related to the diffraction of X‐rays on the phase grating at the X‐ray entrance and exit from the crystal. A model of X‐ray diffraction on the W phase diffraction grating is proposed. 相似文献
14.
Vladimir M. Kaganer Ilia Petrov Liubov Samoylova 《Acta Crystallographica. Section A, Foundations and Advances》2020,76(1):55-69
The use of strongly bent crystals in spectrometers for pulses of a hard X‐ray free‐electron laser is explored theoretically. Diffraction is calculated in both dynamical and kinematical theories. It is shown that diffraction can be treated kinematically when the bending radius is small compared with the critical radius given by the ratio of the Bragg‐case extinction length for the actual reflection to the Darwin width of this reflection. As a result, the spectral resolution is limited by the crystal thickness, rather than the extinction length, and can become better than the resolution of a planar dynamically diffracting crystal. As an example, it is demonstrated that spectra of the 12 keV pulses can be resolved in the 440 reflection from a 20 µm‐thick diamond crystal bent to a radius of 10 cm. 相似文献
15.
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
16.
《Journal of Applied Crystallography》2018,51(3):761-767
This article reports the development and characterization of a laboratory‐based high‐resolution X‐ray powder diffractometer equipped with a 5.5 T magnet and closed‐cycle helium cryostat that is primarily designed for the investigation of magneto‐structural phase transitions. Unique features of the diffractometer include the position‐sensitive detector, allowing the collection of an entire diffraction pattern at once, and the high energy resolution with Mo Kα1 radiation. The ability to utilize a lower energy resolution but higher photon flux by switching to an X‐ray mirror monochromator makes it a versatile setup for a variety of compounds. In this contribution, details of the design and performance of the instrument are presented along with its specifications. 相似文献
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18.
G. Durgababu G. J. Nagaraju G. Bhagavannarayana 《Journal of Applied Crystallography》2020,53(4):972-981
Good quality single crystals of 2,4‐dinitrophenol (DNP)‐doped tristhioureazinc(II) sulfate (ZTS) were successfully grown by employing the simple and cost effective slow‐evaporation solution technique. To study the effect of doping on various device properties, the grown single crystals were subjected to powder X‐ray diffraction (PXRD), high‐resolution XRD, thermogravimetric analysis (TGA), Vickers hardness testing, and UV–visible, photoluminescence (PL) and Fourier transform IR (FTIR) spectroscopy techniques. The crystal structure of DNP‐doped ZTS bulk single crystals remained the same as the crystal structure of ZTS. However, the changes in intensities of the diffraction peaks in the PXRD spectra indicated the incorporation of dopants into the crystalline matrix. FTIR studies confirm the incorporation of dopants into the crystalline matrix, shown by the shifting of certain prominent absorption bands towards higher energy. This also indicated the induced useful strain due to doping, leading to charge transfer and the enhancement of nonlinear optical properties. The cut‐off wavelength and optical band gap energy of pure ZTS and DNP‐doped ZTS crystals were studied by UV–visible absorption spectroscopy, revealing a slight reduction in the optical band gap energy due to doping, which in turn revealed the enhancement of the optical range. PL studies revealed an enhanced optical range of photoluminescence in ZTS crystals. Second harmonic generation (SGH) studies carried out by the Kurtz powder technique revealed the enhancement of SHG value due to DNP doping. To ensure the thermal stability and mechanical strength of the grown crystals with doping (required from the point of view of device applications), TGA and Vicker's hardness studies were performed. 相似文献
19.
Sebastian Send Ali Abboud Nadja Wiesner Mohammad Shokr Manuela Klaus Christoph Genzel Tuba Conka-Nurdan Dieter Schlosser Martin Huth Robert Hartmann Lothar Strüder Ullrich Pietsch 《Journal of Applied Crystallography》2016,49(1):222-233
In this work the spectroscopic performance of a pnCCD detector in the ultra‐hard energy range between 40 and 140 keV is tested by means of an energy‐dispersive Laue diffraction experiment on a GaAs crystal. About 100 Bragg peaks were collected in a single‐shot exposure of the arbitrarily oriented sample to white synchrotron radiation provided by a wiggler at BESSY II and resolved in a large reciprocal‐space volume. The positions and energies of individual Laue spots could be determined with a spatial accuracy of less than one pixel and a relative energy resolution better than 1%. In this way the unit‐cell parameters of GaAs were extracted with an accuracy of 0.5%, allowing for a complete indexing of the recorded Laue pattern. Despite the low quantum efficiency of the pnCCD (below 7%), experimental structure factors could be obtained from the three‐dimensional data sets, taking into account photoelectric absorption as well as Compton scattering processes inside the detector. The agreement between measured and theoretical kinematical structure factors calculated from the known crystal structure is of the order of 10%. The results of this experiment demonstrate the potential of pnCCD detectors for applications in X‐ray structure analysis using the complete energy spectrum of synchrotron radiation. 相似文献
20.
Using channeling‐enhanced energy‐dispersive X‐ray spectroscopy (EDX), we demonstrate polarity sensitive orientation determination of a non‐centrosymmetric crystal in the scanning electron microscope. The authors observe a characteristic asymmetry in the channeling‐enhanced, angle‐dependent EDX data of a GaAs sample, which is in good agreement to simulations using the dynamical theory of diffraction for the incident electron beam. This allows us to assign the orientation of the GaAs crystal according to the non‐centrosymmetric point group. The method shown here overcomes the limitation of a reduced point‐group sensitivity of electron backscatter diffraction patterns and electron channeling patterns for crystalline phases that contain atoms of approximately equal electron scattering cross sections. 相似文献