The use of X-ray powder diffraction as a method for air monitoring was discussed. Most of the airborne dusts monitored by this method have been crystalline compounds, which indicates that they will give distinctive X-ray diffraction patterns. Primarily X-ray powder diffraction has been used for inorganic compounds. The report discussed the principle of the method including theory, qualitative anal
The glass-forming ability (GFA) and the magnetic properties of the [(Fe0.5Co0.5)0.75B0.20Si0.05]96Nb4−xYx bulk metallic glasses (BMGs) have been studied. The partial replacement of Nb by Y improves the thermal stability of the glass against crystallization. The saturation mass magnetization (σs) exhibits a maximum around 2 at. % Y, and the value of σs of the alloy with 2 at. % Y is 6.5% larger than that of the Y-free alloy. The coercivity shows a tendency to decrease with increasing Y content. These results indicate that the partial replacement of Nb by Y in the Fe-Co-B-Si-Nb BMGs is useful to simultaneous achievement of high GFA, high σs, and good soft magnetic properties.
View Notes - Powder+Prep+for+XRD from EMS 162l at UC Davis. Chapter 12 Collecting Quality Powder Diffraction Data Many factors affect quality of powder diffraction data (e.g., see Figs.11.1, 11.5,
... is a rapid analytical technique primarily used for phase identification of a crystalline material and can provide information on unit cell dimensions. The analyzed material is finely ...
TY - JOUR. T1 - Study of the phase equilibria in the L-alanine - Sodium nitrate system by optical microscopy and X-ray powder diffraction. AU - Márquez-Ruiz, Denniz. AU - Hernández-Paredes, Javier. AU - Moreno-Corella, Gemma. AU - Esparza-Ponce, Hilda E.. AU - Hernández-Negrete, Ofelia. AU - Álvarez-Ramos, Mario Enrique. PY - 2015/1/1. Y1 - 2015/1/1. U2 - 10.1017/S1431927615009800. DO - 10.1017/S1431927615009800. M3 - Note. SP - 1805. EP - 1806. JO - Microscopy and Microanalysis. JF - Microscopy and Microanalysis. SN - 1431-9276. ER - ...
ICDDs quarterly, (and a special topical issue) international journal, Powder Diffraction, focuses on materials characterization employing X-ray powder diffraction and related techniques. With feature articles covering a wide range of applications, from mineral analysis to epitactic growth of thin films to advances in application software and hardware, this journal offers a wide range of practical applications. ICDD, in collaboration with the Denver X-ray Conference Organizing Committee, has increased services for the subscribers of Powder Diffraction and authors of Advances in X-ray Analysis. Beginning in 2006, ICDD offered a copy of the previous years edition of AXA to Powder Diffraction institutional subscribers who receive both print and on-line versions. This effectively doubles the number of articles annually available to Powder Diffraction subscribers and significantly increases the circulation for the authors in Advances in X-ray Analysis. Subject coverage includes: •Techniques and ...
The title compound, C(10)H(18), a decalin stereoisomer, crystallizes with Z = 0.5 in the space group P2(1)/n. The trans-decalin molecule is located on an inversion centre with both rings in a chair conformation, making for a quasi-flat overall shape. Despite the absence of hydrogen bonds, it crystallizes easily. In this work the unknown crystal structure of trans-decalin has been solved and refined using X-ray powder diffraction data.
Terbium ortho-vanadate, TbVO4 is a textbook example for a cooperative Jahn-Teller transition (JT) mediated by quadrupolar interactions between the 4f moments [2]. At high temperatures TbVO4 crystallises in the tetragonal zircon structure. Upon lowering the temperature through TJT = 33 K it undergoes a cooperative JT transition: the crystal spontaneously distorts along the [110] direction to orthorhombic symmetry. Samples of TbVO4 were kindly provided by P.C. Canfield of Ames Laboratory (USA).. Powder X-ray diffraction diagrams were recorded on a MAR345 online image plate using an X-ray photon energy of 21 keV. Figure 37 shows the field dependence of the X-ray spectrum, as observed at T = 7.5 K (left) and T = 39 K (right) for different magnetic fields. We first consider the zero field measurements at 39 K and 7.5 K. In the high temperature phase we observe two Bragg reflections with Miller indices (using the high temperature tetragonal unit cell, subscript tet) (211)tet near 11.8 deg and (112)tet ...
The thermal stability, glass-forming ability (GFA) and mechanical properties of the Ni,SUB,60,/SUB,Nb,SUB,40−,I,x,/I,,/SUB,Ti,I,,SUB,x,/SUB,,/I, (,I,x,/I,=0 to 40) glassy alloys have been investigated. As the Ti content increases, the supercooled liquid region ,I,ΔT,/I,,SUB,x,/SUB, (= ,I,T,/I,,SUB,x,/SUB,−,I,T,/I,,SUB,g,/SUB,) and reduced glass transition temperature (,I,T,/I,,SUB,g,/SUB,⁄,I,T,/I,,SUB,l,/SUB,) increase, the maximum ,I,ΔT,/I,,SUB,x,/SUB, of 54 K and ,I,T,/I,,SUB,g,/SUB,⁄,I,T,/I,,SUB,l,/SUB, of 0.622 are obtained at 22.5%Ti and 15%Ti, respectively, and then the ,I,ΔT,/I,,SUB,x,/SUB, and the ,I,T,/I,,SUB,g,/SUB,⁄,I,T,/I,,SUB,l,/SUB, gradually decrease. The Ni,SUB,60,/SUB,Nb,SUB,25,/SUB,Ti,SUB,15,/SUB, glassy alloy was formed in a rod form with a diameter up to 1.5 mm. The ,I,T,/I,,SUB,g,/SUB, and ,I,T,/I,,SUB,x,/SUB, of the bulk glassy alloy were 859 K and 906 K, respectively. The Vickers hardness (,I,Hv,/I,), Youngs modulus (,I,E,/I,), compressive fracture strength ...
Solubility enhancement of poorly-soluble active pharmaceutical ingredients (APIs) remains a scientific challenge and poses a practical issue in the pharmaceutical industry. The emergence of pharmaceutical cocrystals has contributed another dimension to the diversity of crystal forms available at the disposal of the pharmaceutical scientist. That pharmaceutical cocrystals are amenable to the design principles of crystal engineering means that the number of crystal forms offered by pharmaceutical cocrystals is potentially greater than the combined numbers of polymorphs, salts, solvates and hydrates for an API. The current spotlight and early-onset dissolution profile (spring-and-parachute effect) exhibited by certain pharmaceutical cocrystals draw attention to an immediate question: How big is the impact of cocrystals on aqueous solubility? The scientific literature and in-house data on pharmaceutical cocrystals that are thermodynamically stable in water are reviewed and analyzed for trends in aqueous
The present invention relates to a crystal of 1-ethyl-7-methyl-3-{4-[(3-methyl-3H-imidazo[4,5-b]pyridin-2-yl)oxy]phenyl}-1,3-dihydro-2H-imidazo[4,5-b]pyridin-2-one useful as a prophylactic or therapeutic agent for schizophrenia and the like, which shows an X-ray powder diffraction pattern having characteristic peaks at interplaner spacings (d) of 13.59 plus or minus 0.2 and 6.76 plus or minus 0.2 Angstroms in powder X-ray diffraction.
Amorphous solid dispersions (SDs) are a promising approach to improve the dissolution rate of and oral bioavailability of poorly water-soluble drugs. In some cases multi-phase, instead of single-phase, SD systems with amorphous drug are obtained. While it is widely assumed that one-phase amorphous systems are desirable, two-phase systems may still potentially exhibit enhanced stability and dissolution advantages over undispersed systems. The objective of the present study was to understand the solid-state properties of two-phase SDs with amorphous drug and their relation to physical stability. Two different types of excipients for SD formation were used, one being a polymer and the other a small molecule excipient. The supercooled molten SDs of a poorly water-soluble indomethacin (IND) with a graft copolymer, Soluplus® (SOL) and sugar alcohol, xylitol (XYL) were prepared. Supercooled molten SDs of IND with SOL were two-phase glassy suspension in which the amorphous drug was dispersed in an ...
Note for Fig 2. and Fig 3.: The description peanut shell for the shape of Fig. 2(c) and buttoned cushion for that of Fig 3(c) are not technical! - and may not convey familiar images to all readers. The purpose is simly to provide an easy way to referring to these two very different forms of the prepresentational surface for r.m.s.d.A (and, later, r.m.s.m.A). ...
Our primary instrument in the X-ray powder diffraction (XRPD) lab is a PANalytical XPert Pro MPD. We also have a second Philips X-ray set that can be used as a back-up instrument if needed: ...
Cuprous oxide nanoclusters, microcubes and microparticles were successfully synthesized by a simple co-precipitation method. Phase purity and crystallinity of the samples were studied by using X-ray powder diffraction. Transmission electron microscopy (TEM) images show different morphologies like nanoclusters, microcubes and microparticles. For linear and nonlinear optical measurements, the as-synthesized Cu2O with different morphologies were dispersed in isopropanol solution. The absorption spectrum recorded in the visible regions shows peaks that depend on the morphology of the particles and the peak shifts towards red region as one goes from nanoclusters to microparticles. Simple open-aperture Z-scan technique is used to measure nonlinear optical properties of cuprous oxide at 532 nm, 30 ps excitation at 10 Hz repetition rate. Cuprous oxide nanoclusters show reverse saturable absorption (RSA) behaviour, the microcubes and microparticles at a similar concentration exhibit saturable absorption ...
Two special dynamical transitions of universal character have recently been observed in macromolecules (lysozyme, myoglobin, bacteriorhodopsin, DNA and RNA) at T* similar to 100-150 K and T-D similar to 180-220 K. The underlying mechanisms governing these transitions have been the subject of debate. In the present work, a survey is reported on the temperature dependence of structural, vibrational and thermodynamical properties of a nearly anhydrous amino acid (orthorhombic polymorph of the amino acid L-cysteine at a hydration level of 3.5%). The temperature dependence of x-ray powder diffraction patterns, Raman spectra and specific heat revealed these two transitions at T* = 70 K and T-D = 230 K for this sample. The data were analyzed considering amino acid-amino acid, amino acid-water, water-water phonon-phonon interactions and molecular rotor activation. Our results indicated that the two referred temperatures define the triggering of very simple and particular events that govern all the ...
TY - JOUR. T1 - Hatóanyagok oldódásának elocombining double acute accentsegítése extrúziós technoló giával. AU - Gergo, Patyi. AU - György, Marosi. AU - István, Antal. AU - Attila, Bódis. PY - 2009. Y1 - 2009. N2 - The transformation of the stable crystalline form can enhance the bioavailability of poorly water soluble drugs. The molecular dispersion, or solid solution, can be formed by various methods. The thermodynamic and kinetic properties of such compounds are very similar to the amorphous state. Twinscrew melt-extrusion, with controlled pressure, heat and shear stress, is a powerful way for separating the molecules of the active ingredient from each other and distributing them in the matrix homogenously. The extrudate can be processed onward immediately after a required cooling phase. The dependence of the possible effect of extrusion on the process parameters was investigated by Raman-microscopy and X-ray powder diffraction in course of the preparation of solid solution of ...
Amorphous solid-state form of (R)-(+)-7-(3-amino-2,3,4,5,6,7-hexahydro-1H-azepin-1-yl)-1,4-dihydro-4-oxoquinoline-3-carboxylic acid is characterized by at least one of: (a) an X-ray powder diffraction
Mookherjee M , Redfern S A T , Swainson I , Harlov D E , Physics and Chemistry of Minerals , 31 (2004) p.643-649, Low-temperature behaviour of ammonium ion in buddingtonite, [N(D/H)4AlSi3O8] from neutron powder diffraction, Sample: T = 11 K ...
Abstract: The crystal and magnetic structures of SrLnFeRuO6 (Ln = La, Pr, Nd) double perovskites have been investigated. All compounds crystallize with an orthorhombic Pbnm structure at room temperature. These materials show complete chemical disorder of Fe and Ru cations for all compounds. The distortion of the structure, relative to the ideal cubic perovskite, has been decomposed into distortion modes. It has been found that the primary modes of the distortion are octahedral tilting modes: R+4 and M+3. The crystal structure of SrPrFeRuO6 has been studied from room temperature up to 1200 K by neutron powder diffraction. There is a structural phase transition from orthorhombic (space group Pbnm) to trigonal (space group ...
Dorobek naukowy Publikacje WYKAZ DOROBKU PRACOWNIKÓW INSTYTUTU FARMACEUTYCZNEGO ZA ROK Chem. Comm., Distinguishing between polymorphic forms of linezolid by solidphase electronic and vibrational
Powder diffraction was developed independently in 1916 by Peter Debye and Paul Scherrer in Germany and Albert Hull in the U.S. To commemorate this 100th anniversary, a half-day symposium on historical developments in powder diffraction as well as contemporary APS work was held on November 11, 2016.. Where the speakers have agreed, recordings of the talks and slides have been placed in youtube.. David Cox, Brookhaven National Laboratory (Retired) "Some Recollections from the Early Days of Neutron and Synchrotron X-ray Powder Diffraction". Tim Fawcett, International Centre for Diffraction Data "100 Years of Powder Diffraction". Pete Chupas, Advanced Photon Source "80+ Years of Pair Distribution Function Measurements". Andrey Yakovenko, Advanced Photon Source "New In-Situ Capabilities at 17-BM Rapid Acquisition Powder Diffraction Line". Saul Lapidus, Advanced Photon Source "Improving On Great: The High-Resolution Powder Diffractometer, 11-BM". Olaf J. Borkiewicz, Advanced Photon Source "Whats New ...
0006] WO patent application publication No. 99/64405 disclosed five crystalline forms, Form 1 (characterized by an x-ray powder diffraction patterns having peaks expressed as 2θ at about 6.0, 6.3, 10.3, 10.8, 14.1, 16.8, 20.0, 20.5, 21.1 and 24.8 degrees), Form 2 (characterized by an x-ray powder diffraction patterns having peaks expressed as 2θ at about 6.8, 9.2, 12.3, 16.2, 21.4, 22.7, 24.1 and 28.0 degrees), Form 3 (characterized by an x-ray powder diffraction patterns having peaks expressed as 2θ at about 7.1, 7.3, 11.0, 13.8, 20.9, 23.3, 27.9 and 33.5 degrees), Form 4 (characterized by an x-ray powder diffraction patterns having peaks expressed as 2θ at about 3.6, 6.3, 9.7, 11.0, 12.7, 13.2, 16.1, 19.2, 19.5, 20.6 and 24.3 degrees) and Form 5 (characterized by an x-ray powder diffraction patterns having peaks expressed as 2θ at about 10.2, 11.4, 11.6, 12.6, 19.1, 20.6, 21.3, 22.8, 24.8, 27.4, 28.2 and 31.6 degrees) of efavirenz ...
SIMULATION OF X-RAY POWDER DIFFRACTION PATTERNS ON THE BASE OF THE MODELS OF IMPERFECT CRYSTALS S.V. Cherepanova, S.V. Tsybulya. J. Mater. Sci. Forum, Trans Tech Publications Inc., Zurich, Switzerland, 443-444 (2004) pp. 87-90.. Software for the simulation of X-ray powder diffraction (XRPD) patterns for ultrafine grained materials with some kinds of imperfections has been developed. These calculations are performed on the base of the model of one dimensionally disordered crystal. Such a model can described stacking faults and other planar defects and also finite size of coherently scattering domains. Simulated XRPD pattern is compared with the experimental one and can be fitted to it. Potentialities of the software are illustrated by several examples.. PROTONATION SITE AND HYDROGEN BONDING IN ANHYDROUS AND HYDRATED CRYSTALLINE FORMS OF DOXAZOSINE MESYLATE FROM POWDER DATA. V.V. Chernyshev*, D. Machon**, A. Fitch*, S.A. Zaitsev*, A.V. Yatsenko*, A.N. Shmakov, H.-P.Weber** (*Moscow Lomonosov State ...
TY - JOUR. T1 - Coamorphous drug systems: enhanced physical stability and dissolution rate of indomethacin and naproxen. AU - Löbmann, Korbinian. AU - Laitinen, Riikka. AU - Grohganz, Holger. AU - Gordon, Keith C.. AU - Strachan, Clare. AU - Rades, Thomas. PY - 2011. Y1 - 2011. N2 - One of the challenges in drug development today is that many new drug candidates are poorly water-soluble, and one of the approaches to overcome this problem is to transfer a crystalline drug into its amorphous form, thus increasing dissolution rate and apparent solubility of the compound. In this study, a coamorphous drug/drug combination between the two nonsteroidal anti-inflammatory drugs, naproxen and ¿-indomethacin, was prepared and investigated. At molar ratios of 2:1, 1:1 and 1:2, the drugs were quench cooled in order to obtain a coamorphous binary phase. Physical stability was examined at 277.15 and 298.15 K under dry conditions (phosphorus pentoxide) and analyzed with X-ray powder diffraction (XRPD). ...
This course covers one of the most utilized analytical methods in geology and materials characterization, powder X-ray diffraction. It is a hands-on active learning course involving theory and application of diffraction to phase identification, structural analysis and quantitative analysis of clays, soils, sediments, etc. It also covers the mineralogy and crystal chemistry of the clay minerals. Prerequisites: GLG 201 and CHM 141 or permission of instructor.. Back to top. ...
Synthesis and structural characterisation of metal hydrides in two important systems are presented. The first system presented is low valent cobalt and nickel complex hydrides with the compositions BaMg5Co2H10, RbMg5CoNiH10, SrMg2CoH7and Sr4Mg4Co3H19 featuring nickel with oxidation state of 0 and cobalt with oxidation state +I and -I. The second system presented is polyanionic gallium complex hydrides with the compositions RbGaH2, RbxK(1−x)GaH2 (0.5≤x≤1), CsxRb(8−x)Ga5H15 (0≤x≤8) and Cs10Ga9H25 featuring novel hydrogenous polyanionic gallium hydride clusters mimicking common hydrocarbons. The syntheses of the compounds were performed at elevated temperatures and at moderate hydrogen pressures (50-100 bar). The structural investigations were mainly done by X-ray powder diffraction (XRPD) and neutron powder diffraction (NPD). The metal-hydrogen bond was investigated by vibrational spectroscopy using Fourier Transform IR-spectroscopy (FTIR) and Inelastic Neutron Scattering (INS).By ...
Fully green materials have experienced fast growth in the past several decades,and cellulose nanofiber (CNF) and cellulose nanocrystal (CNC) are the preferred choice for the manufacture of environmentally friendly nanocomposites and fully green bionanocomposites. We focus on the recent research and progress made on cellulose-reinforced bionanocomposites where CNF or CNC serves as the nanophase in a matrix made of synthetic or bio-based polymers or their derivatives. At the same time, the role of CNF and CNC in these bionanocomposites will be elucidated and elaborated upon. Finally, the perspective and current challenges of CNF- and CNC-enhanced bionanocomposites in future preparation andapplication are outlined.. ...
Article Photocatalytic hydrogen generation from water under visible light using core/shell nano-catalysts. A microemulsion technique was employed to synthesize nano-sized photocatalysts with a core (CdS)/shell (ZnS) structure. The primary particles o...
Introduction Phase identification from a powder diffraction pattern is a widely used method. Modern computer search-match programs coupled with the ICDD Powder Diffraction File (PDF) database (or with custom databases, Pauling, etc) are now probably more than 20 [1-4], and use various algorithms. However, their respective efficiency is unknown : "To date, no search/match program has proved to be completely satisfactory in all cases..." [2]. Promises of better approaches by using the full trace of known powder patterns were also made : "Nevertheless, the use of PDF-3 for the identification of unknown samples may well become a standard technique at some time in the future "[2]. This future is still awaited. Wasting time because a compound was believed wrongly to be new since a search-match was negative is something that should not happen nowadays. Knowing more about this software category is imperative. This Round Robin is completely open to academic researchers, manufacturers, developers (given ...
in situ diffraction experiments are excellent tools to get detailed insight in the behavior of functional materials, such as porous compounds, nanoscaled catalysts or metal hydrides. During a reaction, catalysts may not only pass through structural transformations or changes of the microstructure. Also particle growth or phase segregation may occur. Experiments under elevated temperatures are of high value if sintering effects or phase changes influence catalytic properties significantly. The catalytic decomposition of ammonia has been used as a model reaction to analyze catalysts under reaction conditions. The analysis of molybdenum catalysts under NH3 atmosphere shows the formation of MoNx starting from the metal oxide precursor, structural phase changes and a change of the microstructure. These facts are correlated with changes of the catalytic activity and stability ...
Red crystals of N,N′-bisIJ3-methoxysalicylidene)-1,5-diiminonaphthalene were obtained after Schiff base condensation in ethanol. Recrystallization from acetone afforded yellow crystals, a process which is reversible and reproducible. Single crystal X-ray diffraction evidences two polymorphs differing in their space group and dihedral angle between aromatic moieties. DFT periodic calculations further confirmed the existence of two minima on the potential energy surface corresponding to red and yellow crystals. The red polymorph irreversibly (monotropically) transforms at 165-190 °C into the yellow one with a 3% increase of the unit cell volume, as shown by X-ray powder diffraction and periodic DFT calculations. Both polymorphs are thermochromic but only the red one displays photochromism upon irradiation at λ = 365 nm, which is reversible and exhibits a relatively slow thermal relaxation. A temperature induced cis/trans-keto equilibrium is for the first time identified for an N-salicylidene ...
A new type of Sr-containing sialon polytypoid phase with the structural formula SrSi10-xAl18+xN32-xOx (x approximate to l) has been found in the Sr-Si-Al-O-N system. The phase was characterised by X-ray powder diffraction (XRPD), and its structure was investigated by electron diffraction (ED) and high resolution electron microscopy (HREM). It is considerably disordered, but the average structure has a rhombohedral unit cell with a=5.335(5)approximate to root 3.a(AIN) and c= 79.1(1)Angstrom approximate to 30.c(AIN). The Sr atoms ave located in layers M-Sr-M, M=(Si/Al), at the origin of the unit cell with 12 X= (O,N) atoms around it, at distances of similar to 3 Angstrom, forming a cubo-octahedron. The X atoms that form a hexagon around the Sr atom in the ab plane are corner shared by M = (Si/Al) tetrahedra with opposite polarity in adjacent layers in which 2/3 of the tetrahedra are occupied. The M-Sr-M layers alternate with normally eight-layer-thick AIN type blocks, although the thickness of ...
Aree di interesse: Expertise in material chemistry activities aiming to design, fabricate and process inorganic solids at the nanoscale. The main activities have include: -Synthesis of nanoparticles, also in quantum confinement regime, with control on size shape and crystalline phase, in order to finely tune their chemical-physical properties -Functionalization of the nanoparticles with surface chemistry exchange procedures -Characterization of the colloidal nanoparticles with spectroscopical UV-vis-NIR absorption, luminescence, FTIR, XPS), structural (transmission microscope, X-ray powder diffraction) and morphological (AFM) techniques -Organization in mesoscopical structures (films, 2/3 D assemblies, polymer based nanocomposites, hybrid electrodes) of the prepared nano-objects with tailored functional properties -Investigation of the unusual size-and shape-dependent (photo)catalytic and opto-electronic properties of the newly fabricated nanostructured materials carried out to assess their ...
A thermal reaction of Li3N and GaCl3 in which benzene was used as the solvent under pressure has been carried out for the preparation of 30-nanometer particles of gallium nitride (GaN) at 280°C. This temperature is much lower than that of traditional methods, and the yield of GaN reached 80%. The x-ray powder diffraction pattern indicated that sample was mainly hexagonal-phase GaN with a small fraction of rocksalt-phase GaN, which has a lattice constant a = 4.100 angstroms. This rocksalt structure, which had been observed previously only under high pressure (at least 37 gigapascals) was observed directly with high-resolution electron microscopy. ...
The book contains the only available complete presentation of the mode-coupling theory (MCT) of complex dynamics of glass-forming liquids, dense polymer melts, and colloidal suspensions.
A crystalline form of 5(S)-(2-hydroxyethoxy)-20(S)-camptothecin diastereoisomer of 5(RS)-(2-hydroxyethoxy)-20(S)-camptothecin is described that is characterized by having an X-ray powder diffraction pattern comprising one or more peak intensities expressed in degrees 2.theta. that are selected from the group consisting of 7.2.+-.0.1, 9.4.+-.0.1, 11.02.+-.0.1, 12.00.+-.0.1, 14.54.+-.0.1, 15.2.+-.0.1, 18.92.+-.0.1, 21.86.+-.0.1, 22.74.+-.0.1 and 26.42.+-.0.1. Methods of making and using the compound are also described.
Radiation damage in minerals is caused by the alpha-decay of incorporated radionuclides, such as U and Th and their decay products. The effect of thermal annealing (400-1400 K) on radiation-damaged pyrochlores has been investigated by Raman scattering, X-ray powder diffraction (XRD), and combined differential scanning calorimetry/thermogravimetry (DSC/TG) (Zietlow et al., in print). The analysis of three natural radiation-damaged pyrochlore samples from Miass/Russia (6.4 wt% Th, 23.1·1018 α-decay events per gram (dpg)), Zlatoust/Russia (6.3 wt% Th, 23.1·1018 dpg), Panda Hill/Tanzania (1.6 wt% Th, 1.6·1018 dpg), and Blue River/Canada (10.5 wt% U, 115.4·1018 dpg), are compared with a crystalline reference pyrochlore from Schelingen (Germany). The type of structural recovery depends on the initial degree of radiation damage (Panda Hill 28 %, Blue River 85 %, Zlatoust and Miass 100 % according to XRD), as the recrystallization temperature increases with increasing degree of amorphization. Raman spectra
The temperature dependence of lattice parameters a in the quasiperiodic plane and c in the periodic direction of decagonal Al70.7Co13.3Ni16.0 was probed using X-ray powder diffraction in the temperature range 15-300 K. Both parameters were fitted by means of positions of 22 Bragg reflections for each temperature. Temperature dependences were modelled best by second order polynomials leading to linear thermal expansion coefficients α(T) = 8.1(33) · 10-7K-1 + 3.9(2) · 10-8K-2 T in the quasiperiodic plane and γ(T) = 1.7(6) · 10-6K-1 + 3.8(3) · 10-8K-2 T in the periodic direction, respectively. Thus we found the anisotropy ratio γ(T)/α(T) to decrease with increasing temperature from 1.60 (at 15 K) to 1.05 (at 300 K). Besides pecularities around 150 K indicating an intermediate phase formed by superordering, we observed deviations from the general smooth course between 15 K and 50 K for both lattice parameters. ...
Polycrystalline samples of the series La{sub 2−x}Ca{sub x}CoIrO{sub 6} (0≤x≤1.2) have been synthesized and its structural and magnetic properties were investigated using experiments of X-ray powder diffraction, temperature dependent magnetic susceptibility and magnetization as a function of applied magnetic field. All grown polycrystalline compounds form in a monoclinic structure (space group P2{sub 1}/n) with a partially ordered distribution of transition metal cations Co/Ir over the six-coordinate sites. Our results indicate variation of the magnetic interactions between Co and Ir magnetic sublattices possibly due to valence changes of the transition metals, induced by doping. The undoped La{sub 2}CoIrO{sub 6} presents magnetic ordering at ∼97K, while for Ca-doped compounds a decrease of net magnetization and ordering temperatures was observed. For x=0.2 and 0.5 the emergence of a second magnetic interaction, due to the presence of high spin Co{sup 3+}, becomes evident. Interestingly, ...
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AbeBooks.com: Quantitative X-Ray Diffractometry (9781461395379) by Lev S. Zevin; Giora Kimmel and a great selection of similar New, Used and Collectible Books available now at great prices.
This paper describes the effects of intense synchrotron radiation beams from the Advanced Photon Source on small ferritin crystals suspended in solution. Typical powder diffraction, shown in the figure, identifies a number of individual crystals within the X-ray beam. After exposures in the range 2×107 Grays, the crystals were found to disintegrate suddenly in a spectacular way, as captured on the JSR cover image. The peak evolution to larger momentum transfer implies that the crystals collapse, possibly due to loss of hydration.. ...
In this dissertation, the structure and photoluminescent properties of A3MO4F-type materials (A = Sr, Ba, Ca; M =Al, Ga, In, Si, Ge) are studied as potential phosphors for compact fluorescent lamps (CFLs) and phosphor converted light emitting diode (pc LED) lights. Chapter 1 outlines background information of the evolution of lighting technology as well as detailing the synthesis, structural characterization and photoluminescence measurements. Chapter 2 focuses on the changes that the Sr3AlO4F structure undergoes as a result of exposure to a 5% H2/95% Ar atmosphere. High-resolution neutron powder diffraction is used to probe for minute structural changes. Chapter 3 is a detailed study of the isovalent substitution of Sr2+ by Ba2+ and Ca2+ at the A site in Sr3 xAxGaO4F. In this study, changes in bond valence sums, global instability indices, and photoluminescent properties are related as a result of these substitutions. As the Ba2+ content increases in Sr3 xAxGaO4F, the global instability indices
The synthesis, characterization and thermogravimetric study of the adducts ZnCl2.2Imi, ZnBr2.2Imi, CdCl.Imi, CdCl2.2Imi, CdBr2.2Imi, CdBr2.3Imi, CdI2.2.5Imi, HgCl2.2Imi, HgBr2.1.5Imi and HgI2.1.5Imi (Imi = imidazole) is reported. The following sequence of thermal stability is observed for the synthesized adducts: Zn , Hg , Cd. It is also verified that larger cations, as well as larger anions, result in a smaller number of imidazole molecules in the coordination sphere of the considered cation and that hard acids exhibit stronger bonds to imidazole than soft acids, and this fact is reflected in the thermal stability sequence. ZnCl2.2Imi behaves as a non-electrolyte in acetonitrile and ethanol, whereas ZnBr2.2Imi is a non-electrolyte in acetonitrile and a 1:1 electrolyte in ethanol. CdI2.2.5Imi is a non-electrolyte in acetonitrile and a 1:2 electrolyte in ethanol. (C) 2003 Elsevier B.V. All rights reserved ...
Learn how the indexation of powder X-ray diffraction patterns using the WinXPOW software was applied to crystals of layered transition metal dichalcogenides.. ...
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Specifications Catalogue No.: 11952 Product Name: L-Arginine hydrochloride Synonyms: L-Arginine monohydrochloride; H-Arg-OH.HCl CAS: 1119-34-2 EC: 214-275-1 MDL: MFCD00064550 Formula: C6H15ClN4O2 MW: 210.66 -------------------------------------------------- Price: USD260/1kg Price: USD620/5kg Price(bulk): Email Us Properties Standard USP31 Assay 98.5~101.0 % Appearance white crystalline powder pH 4.7~6.2 Specific rotation D25 +22.1~+22.9° Transmittance T430 98.0% min Chloride(Cl) 16.58~17.00% Ammonium(NH4) 0.02% max…
In 1996 Abbott launched on the market an effective protease inhibitor Norvir® that had cost the company in excess of $200 million to develop. The drug was formulated as an encapsulated ethanol/water solution. In the summer of 1998, supplies of the drug were interrupted by the appearance of a new crystal form (polymorphism) at a plant in the USA and then later at a plant in Italy. This new, more thermodynamically stable polymorphic form had very different physical properties than the earlier material and Abbott was forced to withdraw the drug from sale. The new form failed dissolution tests and precipitated out within the capsules. The company lost an estimated $250 million in sales as well as hundreds of millions of dollars trying to recover the original polymorph while the product was off the market. No doubt many AIDS sufferers were not helped by the products absence. What appeared to have happened was that a degradation product obtained during manufacturing had initiated the appearance of a ...
The THEMYS is the NEW benchmark for modular thermogravimetric analysis. The THEMYS is available in various platforms: TGA, STA, TG/DSC, EGA...