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X-ray Diffractometer (x-ray + diffractometer)
Selected AbstractsInterdiffusion phenomena in InGaAs/GaAs superlattice structuresCRYSTAL RESEARCH AND TECHNOLOGY, Issue 5 2010B. Sar, kavak Abstract We have studied structural properties of InGaAs/GaAs superlattice sample prepared by Molecular Beam Epitaxy (MBE) using high resolution X-ray diffractometer (HRXRD). Increasing strain relaxation and defect generations are observed with the increasing Rapid Thermal Annealing (RTA) temperature up to 775 °C. The higher temperatures bring out relaxation mechanisms; interdiffusion and favored migration. The defect structure and the defects which are observed with the increasing annealing temperature were analyzed. Firstly, the in-plane and out-of-plane strains after the annealing of sample were found. Secondly, the structural defect properties such as the parallel X-ray strain, perpendicular X-ray strain, misfit, degree of relaxation, x composition, tilt angles and dislocation that are obtained from X-ray diffraction (XRD) analysis were carried out at every temperature. As a result, we observed that the asymmetric peaks especially in asymmetric (224) plane was affected more than symmetric and asymmetric planes with lower polar or inclination angles due to c-direction at low temperature. These structural properties exhibit different unfavorable behaviors for every reflection direction at the increasing temperatures. The reason is the relaxation which is caused by spatially inhomogeneous strain distribution with the increasing annealing temperature. In the InGaAs superlattice samples, this process enhances preferential migration of In atoms along the growth direction. Further increase in the annealing temperature leads to the deterioration of the abrupt interfaces in the superlattice and degradation in its structural properties. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] A novel growth method for ZnAl2O4 single crystalsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 3 2006K. Kumar Abstract ZnAl2O4 is a well-known wide band gap compound semiconductor (Eg=3.8eV), ceramic, opto-mechanical, anti-thermal coating in aero-space vehicles and UV optoelectronic devices. A novel method for the growth of single crystals of a ternary oxide material was developed as a fruit of a long term work. Material to be grown as metal incorporated single crystal was taken as precursor and put into a bath containing acid as reaction speed up reagent (catalyst) as well as solvent with a metal foil as cation scavenger. Using this method, ZnAl2O4 crystals having hexagonal facets are prepared from a single optimized bath. Structural and compositional properties of crystals were studied using Philips, Xpert - MPD: X-ray diffractometer and Philips, ESEM-TMP + EDAX. Thus technique was found to be a new low cost and advantageous method for growth of single crystals of ternary oxide a material. We hope that these data be helpful either as a scientific or technical basis in material processing. Dedicated to Prof. P. Ramasamy © 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim [source] Unlubricated Wear Behavior of Ce-TZP/ Al2O3 Nanocomposites Against Bearing Steel,ADVANCED ENGINEERING MATERIALS, Issue 3 2005G. Yang Unlubricated friction and wear tests of Ce-TZP/Al2O3 nanocomposites against bearing steel were performed. In order to elucidate the wear mecahnism, the morphological investigation and phase structural analysis of worn surfaces were carried out by X-ray diffractometer and scanning electron microscope. Additionally, three kinds of wear mechanisms such as plastic deformation, adhesive wear and brittle fracture have been revealed. [source] Synthesis and spectral studies of diorganotin heterocyclic dithiocarbamate complexes and crystal structures of (2- F -Bz)2Sn(Cl) S2CN(CH2CH2)2NEt and (3- Cl -Bz)2Sn [S2CN(CH2CH2)2NEt]2 , 0.5HN(CH2CH2)2NHHETEROATOM CHEMISTRY, Issue 4 2005Shengcai Xue Some new diorganotin(IV) complexes of heterocyclic dithiocarbamate having general formula R2Sn(Cl)S2CNR'2 and R2Sn(S2CNR'2)2 [R = 2-F-Bz, 3-Cl-Bz; NR'2 = N(CH2CH2)2NMe, N(CH2CH2)2NEt, and N(CH2CH2)2NBz] have been prepared, respectively. Elemental analyses, IR, and NMR spectral data characterized all compounds. The crystal structures of (2-F-Bz)2Sn(Cl)S2CN(CH2CH2)2NEt 2 and (3-Cl-Bz)2Sn[S2CN(CH2CH2)2NEt]2 , 0.5 HN(CH2CH2)2NH 5 were determined by single crystal X-ray diffractometer. In the crystal of complex 2, the tin atom is rendered five-coordination in a trigonal bipyramidal configuration by coordinating with S atoms of dithiocarbamate groups. For complex 5, the central Sn atom exists in a skew-trapezoidal planar geometry defined by two asymmetrically coordinated dithiocarbamate ligands and two 3-chlorobenzyl groups. © 2005 Wiley Periodicals, Inc. 16:271,277, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20096 [source] A simple hermetic sample holder for X-ray diffraction analysis of uranium hydrideJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 4 2007Bingyun Ao In order to help resolve unknowns regarding aging effects of uranium during long-term storage of tritium, a number of experiments have been carried out by several researchers. However, almost no literature is available on the structural change of uranium tritide, mainly because its high toxicity and air-sensitivity render appropriate experiments very difficult. In this paper, a simple hermetic sample holder that fits the Philips X'Pert Pro X-ray diffractometer is described. It may be used to study the aging effects of uranium tritide during storage. The sample holder mainly consists of an aluminium container for sample storage and a Mylar window for X-ray measurements. This sample holder can also be used with other air-sensitive, radioactive and toxic materials. In this paper, the first results obtained from X-ray diffraction analysis of uranium hydride are presented. [source] High-temperature (1500,K) reciprocal space mapping on a laboratory X-ray diffractometerJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 2 2007R. Guinebretière A laboratory X-ray diffractometer devoted to the in situ characterization of the microstructure of epitaxic thin films at temperatures up to 1500,K has been developed. The sample holder was built using refractory materials, and a high-accuracy translation stage allows correction of the dilatation of both the sample and the sample holder. The samples are oriented with respect to the primary beam with two orthogonal rotations allowing the registration of symmetric as well as asymmetric reciprocal space maps (RSMs). The association of a monochromatic primary beam and a position-sensitive detector allows the measurement of RSMs in a few minutes for single crystals and in a few hours for imperfect epitaxic thin films. A detailed description of the setup is given and its potential is illustrated by high-temperature RSM experiments performed on yttria-doped zirconia epitaxic thin films grown on sapphire substrates. [source] A simple and low-cost solution for the automation of X-ray powder diffractometers with chart recorder outputJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 4 2006M. Jayaprakasan X-ray powder diffraction is an established method for the qualitative identification of crystalline materials and their quantitative analysis. The new generation of X-ray diffraction systems are based on expensive digital/embedded control technology and computer interfaces. Yet many laboratories use conventional manual-controlled systems with XY strip-chart recorders. Since the output spectrum is a strip chart (hard copy), raw data, essential for structural and qualitative analysis, are not readily available for further analysis. Upgrading to modern computerized diffractometers is very expensive. The proposed automation design described here is intended to enable the conventional diffractometer user to collect, store and analyze data quickly. The design also improves the resolution by five times compared with the conventional setup. For the automation, a PC add-on card has been designed to control and collect the timing and intensity counts from the conventional X-ray diffractometer, and suitable software has been developed to collect, process and present the X-ray diffraction data for both qualitative and quantitative analysis. Moreover, a major advantage of this design is that it does not warrant any physical modification of the hardware of the conventional setup; it is simply an extension to enhance the performance of collecting raw data with a higher resolution at desired intervals/timings. [source] Symmetrization of diffraction peak profiles measured with a high-resolution synchrotron X-ray powder diffractometerJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 1 2006H. Hibino The asymmetry of diffraction peak profiles observed with a high-resolution synchrotron powder X-ray diffractometer has been successfully removed by a double deconvolution method. In the first step, the asymmetry caused by the axial divergence aberration of the diffractometer is removed by a whole-pattern deconvolution method based on an a priori theoretical model for the aberration. In the second step, the residual asymmetry, the origin of which can be ascribed to the aberrations of the beamline optics, is also removed by a whole-pattern deconvolution method, based on an empirical model derived from the analysis of experimental diffraction peak profiles of a standard Si powder (NIST SRM640b). The beamline aberration has been modelled by the convolution of a pseudo-Voigt or Voigt function with an exponential distribution function. It has been found that the angular dependence of the asymmetry parameter in the exponential function is almost proportional to tan,, which supports the idea that the residual asymmetry should be ascribed mainly to the intrinsic asymmetry in the spectroscopic distribution of the source X-ray supplied by the beamline optics of the synchrotron facility. Recently developed procedures of whole-pattern deconvolution have been improved to treat the singularity of the instrumental function in the measured angular range. Formulae for the whole-pattern deconvolution based on the Williamson,Hall-type dependence of the width parameter of the instrumental function have also been developed. The method was applied to the diffraction intensity data of a standard ZnO powder sample (NIST SRM674) measured with a high-resolution powder diffractometer on beamline BL4B2 at the Photon Factory. The structure parameters of ZnO were refined from the integrated peak intensities, which were extracted by an individual profile fitting method applying symmetric profile models. The refined structure parameters coincide fairly well with those obtained from single-crystal data. [source] Stress and elastic-constant analysis by X-ray diffraction in thin filmsJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 3-2 2003F. Badawi Residual stresses influence most physical properties of thin films and are closely related to their microstructure. Among the most widely used methods, X-ray diffraction is the only one allowing the determination of both the mechanical and microstructural state of each diffracting phase. Diffracting planes are used as a strain gauge to measure elastic strains in one or several directions of the diffraction vector. Important information on the thin-film microstructure may also be extracted from the width of the diffraction peaks: in particular, the deconvolution of these peaks allows values of coherently diffracting domain size and microdistortions to be obtained. The genesis of residual stresses in thin films results from multiple mechanisms. Stresses may be divided into three major types: epitaxic stresses, thermal stresses and intrinsic stresses. Diffraction methods require the knowledge of the thin-film elastic constants, which may differ from the bulk-material values as a result of the particular microstructure. Combining an X-ray diffractometer with a tensile tester, it is possible to determine X-ray elastic constants of each diffracting phase in a thin-film/substrate system, in particular the Poisson ratio and the Young modulus. It is important to notice that numerous difficulties relative to the application of diffraction methods may arise in the case of thin films. [source] A high-resolution X-ray diffractometer for the study of imperfect materialsJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 5 2002A. Boulle A high-resolution X-ray diffractometer devoted to the study of imperfect materials (mainly oxides and ceramics) is presented. It is based on a rotating anode generator, a four-bounce monochromator, a five-movement sample holder and a curved position-sensitive detector (PSD). This setup allows rapid acquisition of a reciprocal-space map (in less than 10,h) even for very poorly diffracting materials. The two-dimensional instrumental profile is calculated taking into account each optical element in the beam path. The one-dimensional instrumental profiles corresponding to widely used scans (, scan, ,,2, scan, rocking curve and powder scan) are also calculated. In the three former cases, the setup exhibits an excellent angular resolution (0.003°), whereas in the latter case the resolution is lowered by one order of magnitude at the benefit of a strong increase in the collected intensity. The possibilities of this diffractometer are illustrated with three examples: an epitaxic layer, a microstructured single crystal and a powder. [source] INFLUENCE OF TEMPERATURE AND RELATIVE HUMIDITY ON THE PHYSICAL STATES OF COTTON CANDYJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 4 2004THEODORE P. LABUZA ABSTRACT Cotton candy is made by melting crystalline sucrose above 210C in a bowl which shoots molten liquid sucrose into the air where it rapidly cools and dries into an amorphous glassy solid state. As such, it is highly hygroscopic, picking up moisture as %RH increases and becoming rubbery. The glass transition line (Tg vs. %RH) divides the two states. When rubbery, cotton candy should collapse forming crystalline sucrose becoming unsaleable. Cotton candy was stored at 25C and at %RH from ,0% to 75%. Moisture gain/loss, visual observations, and powder X-ray diffraction using a Seimens 5005-powder X-ray diffractometer were used to evaluate collapse and crystallization. At ,0% and 11% RH (below Tg), cotton candy maintained a stable structure for at least 12 months. At 33% RH (just at Tg), it collapsed and crystallized within 3 days while at 45, 54 and 75% RH, collapse and crystallization occurred in less than 1 day. [source] Ionic Conductivity Enhancement of La2Mo2,xWxO9 Nanocrystalline Films Deposited on Alumina Substrates by the Sol,Gel MethodJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 4 2009Zhong Zhuang Dense, crack-free, and uniform La2Mo2,xWxO9 (x=0, 0.1, and 0.2) nanocrystalline films were successfully synthesized on poly-alumina substrates via a modified sol,gel method, with inorganic salt of La(NO3)3·6H2O, (NH4)6Mo7O24·4H2O, and (NH4)6H2W12O24 as precursors. Pure La2Mo2O9 phase was confirmed by X-ray diffractometer when the annealing temperature was >500°C. The average grain size of the La2Mo2,xWxO9 films is in the range of 90,400 nm, depending upon the conditions of thermal treatment, and the thickness of films can reach 1 ,m by repetitive spin-coating. The electrical conductivity increases with decreasing grain size and reaches 0.074 S/cm at 600°C in the film with a grain size of 90 nm, which is one order of magnitude higher than that in the corresponding bulk materials. W-doping can suppress the phase transition that occurs at 580°C in pure La2Mo2O9 and enhance the low-temperature ionic conductivity. Furthermore, the activation energy of conductivity in the nanocrystalline La2Mo2O9 films decreases to about 0.6 eV in comparison with 1.0 eV in the bulk ones, which implies that the grain resistance prevails in the total resistance, when grain size reduces to nanometer domain. [source] Synthesis and Characterization of Highly Dispersed Antimony-Doped Stannic Hydroxide Nanoparticles: Effects of the Azeotropic Solvents to Remove Water on the Properties and Microstructures of the NanoparticlesJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 4 2007Fen Yang Highly dispersed antimony (Sb)-doped stannic hydroxide nanoparticles have been successfully prepared using the solution chemistry method. The properties and microstructures of the nanoparticles are investigated in detail by means of infrared, transmission electron microscope, X-ray diffractometer, and Brunauer-Emmett-Teller nitrogen surface area measurements. The results indicate that the properties and microstructures of the nanoparticles strongly depend on the azeotropic solvents used to remove water at the drying stage. Various azeotropic solvents are screened to investigate their effects on the size and dispersivity of dried Sb-doped stannic hydroxide. Three empirical rules are drawn for selecting an effective azeotropic solvent: (1) the solvent molecule should contain at least one atom such as oxygen as the hydrogen (H)-bond acceptor to form H bonds with the surface ,OH (acting as an H-bond donor) of polymer particle; (2) the H-bond acceptor should locate in the middle of the alkane chain rather than on the terminal so that the alkane chain can stretch out and cover more surface area, improving the dispersivity of the dried product; and (3) the solvent should have a higher boiling point (,140°C) to reduce the time of azeotropic distillation for removing water and maintain a lower residual amount of azeotropic agent. Based on the empirical rules, it is discovered that iso-amyl acetate is the most effective azeotropic solvent. [source] Effect of precursor concentration on the structural and optical properties of ZnO nanostructuresPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 7 2010Sharul Ashikin Kamaruddin Abstract Zinc oxide (ZnO) is an emerging material in large area electronic applications such as thin-film solar cells and transistors. We report on the fabrication and characterization of ZnO nanostructures. ZnO nanostructures have been synthesized using sol,gel immerse technique on oxidized silicon substrates. Different precursor's concentrations ranging from 0.0001 to 0.01,M using zinc nitrate hexahydrate [Zn(NO3)2.6H2O] and hexamethylenetetramine [C6H12N4] has been employed in the synthesis of ZnO nanostructures. The surface morphologies were examined using scanning electron microscope (SEM) and atomic force microscopy (AFM). In order to investigate the structural properties, the ZnO nanostructures were measured using X-ray diffractometer (XRD). The optical properties of the ZnO nanostructures were measured using photoluminescence (PL) spectrometer. [source] Ultrasonochemical-assisted fabrication and evaporation- induced self-assembly (EISA) of POSS-SiO2@Ag core/ABA triblock copolymer nanocomposite filmPOLYMER COMPOSITES, Issue 9 2010Murugan Veerapandian Poly(ethylene glycol)-octafunctionalized polyhedral oligomeric silsesquioxane (POSS) (Mn = 5576.6 g/mol) alloying agent stabilized amphiphilic silica@silver metalloid nanocomposite blended with a triblock copolymer poly(p -dioxanone- co -caprolactone)- block -poly(ethylene oxide)- block -poly(p -dioxanone- co -caprolactone) (POSS-SiO2@Ag/PPDO- co -PCL- b -PEG- b -PPDO- co -PCL) has been synthesized in both water and in organic medium utilizing ultrasonochemical reaction. The POSS stabilized pre-made metalloid was successfully dispersed in amphiphilic PPDO- co -PCL- b -PEG- b -PPDO- co -PCL (ABA) triblock copolymer matrix of molecular weight 45.9 × 104 g/mol. The mechanism of synthesis of high concentration of SiO2@Ag nanocomposite from TEOS/AgNO3 (in the presence of NH4OH as catalyst/NaBH4 as reductant) nonmetal/metal precursors and the successful EISA of POSS-SiO2@Ag/ABA nanocomposite into films has been discussed. The successful synthesis of metalloid nanocomposite was morphologically accessed by field emission-scanning electron microscopy, transmission electron microscopy and atomic force microscopy. Surface plasmon resonance was ensured from UV,visible spectral analysis. Identity and the crystallinity of as prepared nanocomposite were studied by X-ray diffractometer. Structural and luminescence properties of the nanocomposite were examined by Fourier transform infrared spectroscopy and photoluminescence. Thermogravimetric analysis was carried out to study the thermal stability of the resulting hybrid nanocomposite. The resultant inorganic,organic nanocomposite can be easily suspended in water and would be useful in variety of applications. POLYM. COMPOS., 31:1620,1627, 2010. © 2009 Society of Plastics Engineers [source] Effect of zeolite 5A on the crystalline behavior of polypropylene (PP) in PP/,-nucleating agent systemPOLYMER COMPOSITES, Issue 12 2008Zhiping Lv The effect of zeolite 5A on the crystalline behavior of polypropylene (PP) in PP/,-nucleating agent system was investigated with X-ray diffractometer (XRD), differential scanning calorimeter (DSC), and polarized light microscope (PLM) in this study. Zeolite 5A has less effect on crystalline phase of PP/,-nucleating agent than does n -CaCO3, which is ascribed to the stronger surficial polarity and better dispersibility of zeolite 5A. The data of DSC indicated that the crystallization peak temperature of PP increases by 8.3°C in the presence of zeolite 5A, and n -CaCO3 increases 5.7°C in PP/TMB-5 system, relative to pure PP. And the initial crystallization temperature (Tc0) and the relative crystallinity (Xc) of PP is much more dramatically raised in the presence of zeolite 5A than CaCO3. The efficiency of zeolite 5A in reducing the spherulites size of PP was seen clearly from the PLM photographs. The mechanical testing results showed that the flexural strength and impact strength of PP/,-nucleating agent system increased in the presence of zeolite 5A. POLYM. COMPOS., 2008. © Society of Plastics Engineers [source] Preparation and linear rheological behavior of polypropylene/MMT nanocompositesPOLYMER COMPOSITES, Issue 3 2003Li Jian Maleic anhydride grafted low isotactic homopolypropylene elastomer (LiPP-g-MAH) is used as a compatibilizer in the melting mixing of polypropylene (PP) and clay. The microstructures of the composites of PP/clay (PPCN) are investigated using a wide-angle X-ray diffractometer (WAXD) and transmission electron microscope (TEM) as well as parallel rheometer, which show that PPCN with different phase morphologies have been obtained. It is found that the weight ratio of LiPP-g-MAH to clay and the weight content of LiPP-g-MAH in PPCN have a strong effect on the final dispersibility of the clay. The rheological response to small amplitude oscillatory shear (SAOS) shows that the storage modulus (G,) at the low frequencies is greatly sensitive to the microstructures in comparison with WAXD measurements. The investigation further indicates that the virgin clay particles, intercalated silicate crystallites, and exfoliated layers may coexist in the matrix at the same time, resulting in the great enhancement of G, plateau at low frequency region. [source] Crystallization and thermal behavior of multiwalled carbon nanotube/poly(butylenes terephthalate) compositesPOLYMER ENGINEERING & SCIENCE, Issue 6 2008Defeng Wu Multiwalled carbon nanotube/poly(butylene terephthalate) composites (PCTs) were prepared by melt mixing. The nonisothermal crystallization and thermal behavior of PCTs were respectively investigated by X-ray diffractometer, polarized optical microscope, differential scanning calorimeter, dynamic mechanical thermal analyzer, and thermogravimetric analyzer. The presence of nanotubes has two disparate effects on the crystallization of PBT: the nucleation effect promotes kinetics, while the impeding effect reduces the chain mobility and retards crystallization. The kinetics was then analyzed using Ozawa, Mo, Kissinger, Lauritzen-Hoffman, and Ziabicki model, and the results reveal that the nucleation effect is always the dominant role on the crystallization of PBT matrix. Thus the crystallizability increases with increase of nanotube loadings. In addition, the presence of nanotubes nearly has no remarkable contribution to thermal stability because nanotubes also play two disparate roles on the degradation of PBT matrix: the Lewis acid sites to facilitate decomposition and the physical hindrance to retard decomposition. Hence the nanotubes act merely as inert-like filler to thermal stability. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers [source] Effects of epoxy resin-modified zinc-ion-coated nanosilica on structural, thermal and dynamic mechanical properties of propylene-ethylene copolymerPOLYMER INTERNATIONAL, Issue 8 2006Chaganti Srinivasa Reddy Abstract This paper reports a comparative study of propylene,ethylene copolymer (EP) nanocomposites synthesized using zinc-ion (Zn2+)-coated nanosilica (ZNS) and the diglycidyl ether of bisphenol-A (DGEBA, an epoxy resin)-modified zinc-ion-coated nanosilica (EZNS) as nanofillers. These nanocomposites were prepared using the ,melt mixing' method at a constant loading level of 2.5 wt%. This loading level is much lower than that used for fillers in conventional composites. The EP nanocomposites were characterized using wide-angle X-ray diffractometer (WAXD), a thermo gravimetric analyzer (TGA), a differential scanning calorimeter (DSC), a dynamic mechanical analyzer (DMA) and scanning electron microscopy (SEM). DMA results showed a higher storage modulus for EP-epoxy-modified Zn2+ -coated nanosilica nanocomposite (EP-EZNS) with respect to EP and EP-Zn2+ -coated nanosilica nanocomposite (EP-ZNS). In addition, TGA thermograms showed an increase in degradation temperature of EP in the presence of EZNS. Copyright © 2006 Society of Chemical Industry [source] Absolute measurement of lattice parameter in single crystals and epitaxic layers on a double-crystal X-ray diffractometerACTA CRYSTALLOGRAPHICA SECTION A, Issue 3 2005M. Fatemi Details of the recently developed `zone technique' for the absolute measurement of lattice parameter and strain in single-crystal solids and thin films are presented. The method is based on measuring X-ray rocking curves from a few equatorial planes within a suitable zone and correcting their peak positions at once with a single zero offset. In contrast to the comparative method, which usually requires use of two opposite azimuthal directions, those in the zone technique can often be completed in only one azimuthal setting. A typical strained layer in the cubic system can be fully and rapidly characterized with only three rocking curves. The technique is suitable for routine applications under typical laboratory conditions, and for high-precision measurements of nearly perfect crystals in a controlled environment, with a potential parts in 10,million accuracy. This degree of accuracy is a direct consequence of the zero offset correction procedure, which effectively cancels a large portion of the misalignment errors in the diffractometer. The use of the (n,,n) geometry substantially reduces the errors of eccentricity compared to the Bond technique, and its stronger reflections enable the measurement of small samples about 0.05,mm in length with relative ease. The technique is illustrated with examples, and its extension to the triple-axis (,,2,) instruments is discussed. [source] Density Investigation by X-ray Reflectivity for Thin Films Synthesized Using Atmospheric CVD,CHEMICAL VAPOR DEPOSITION, Issue 9-10 2008Shinichi Kishimoto Abstract The density of hafnia and titania films is investigated by an X-ray reflectivity (XRR) analysis using an X-ray diffractometer equipped with a relatively low power X-ray source. Several films are prepared using a CVD technique operated under atmospheric pressure. The XRR profile of the hafnia films is obtained, and fitted with the assumption of the existence of an HfSiO intermediate layer on the Si substrate with a SiO2 layer. The density of the hafnia films is lower than that of the bulk crystal. On the other hand, the XRR profile of the titania films on the glass substrate can be fitted using a seven-lamella model. The film density of titania is also lower than that of the bulk crystal. XRR analysis may become a powerful weapon to determine not only the structure model but also the crystallinity of each layer. [source] Preparation, Crystal Structure and Theoretical Calculation of N -(Pyrimidin-2-yl)- N, -methoxycarbonyl-thioureaCHINESE JOURNAL OF CHEMISTRY, Issue 4 2007Ying-Hui Ren Abstract The compound, N -(pyrimidin-2-yl)- N, -methoxycarbonyl-thiourea, has been synthesized. The single crystal structure has been determined by an X-ray diffractometer. The crystal belongs to triclinic with space group P -1 and a=0.72152(4) nm, b=0.8056(4) nm, c=0.90772(5) nm, ,=105.141(4)°, ,=94.588(4)°, ,=115.415(4)°, F(000)=220, the unit cell volume V=0.45704(4) nm3, the molecule number in one unit cell Z=2, the absorption coefficient ,=0.333 mm,1, the calculated density Dc=1.542 g/cm3. The theoretical investigation of the title compound was carried out with B3LYP/6-311G, HF/6-311G and MP2/6-311G methods, and the atomic charges and natural bond orbital analysis were also discussed. [source] DETERMINATION OF PIGMENTS AND BINDERS IN POMPEIAN WALL PAINTINGS USING SYNCHROTRON RADIATION , HIGH-RESOLUTION X-RAY POWDER DIFFRACTION AND CONVENTIONAL SPECTROSCOPY , CHROMATOGRAPHYARCHAEOMETRY, Issue 2 2010A. DURAN The employment of synchrotron techniques complemented by conventional laboratory systems has allowed us to deepen and improve our knowledge of Roman wall painting procedures. The palette identified in wall paintings from Pompeii and Herculaneum from the second century bc includes goethite, hematite, cinnabar, glauconite, Egyptian blue, and other components such as calcite and aragonite. Proof of the use of organic binders is provided by FTIR and PY,GC/MS. Therefore, the possibility of the use of ,a secco' techniques cannot be ruled out. Pigments in wall paintings are usually found in small percentages and conventional X-ray diffractometers do not detect them. Synchrotron radiation , high-resolution X-ray powder diffraction has allowed identification with only a few micrograms of sample. [source] Preparation and characterization of electrodeposited indium selenide thin filmsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 6 2005S. Gopal Abstract Indium Selenide (InSe) thin films were deposited from a mixture of Indium chloride and selenium dioxide in aqueous solution by electrodeposition technique on Indium Tin oxide coated glass substrates. The effects of the parameters during deposition such as current density, deposition potential versus saturated calomel electrode, pH value and concentration of source material were studied. X-ray diffraction studies were carried out on the films to analyze the microstructure using an x-ray diffractometer and were examined by RAMAN spectroscopy. The Raman peak position did not change much with chemical concentrations. Raman scattering due to the (LO) phonon was observed at 211 cm,1. Optical absorption studies were performed with a double beam ultra violet-visible ,NIR spectrophotometer in the wavelength 300,1100 nm. The surface morphology of the layer was examined using a scanning electron micrograph. The composition of the films was studied using an Energy Dispersive Analysis by X-Rays (EDAX). [source] | ||||||||||||||||