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Diffraction Spectroscopy (diffraction + spectroscopy)

Distribution by Scientific Domains
Physics and Astronomy66%
Polymers and Materials Science33%

Selected Abstracts

Preparation, physicochemical and third order nonlinear optical properties of bis(tetrabutylammonium)bis(2-thioxo-1,3-dithiole-4,5-dithiolato)mercurate(II)

CRYSTAL RESEARCH AND TECHNOLOGY, Issue 6 2009
X. Q. Wang
Abstract Bis(tetrabutylammonium)bis(2-thioxo-1,3-dithiole-4,5-dithiolato)mercurate(II) was prepared and characterized by elemental analyses, electronic absorption, infrared and X-ray powder diffraction spectroscopy. The specific heat of the crystal was measured to be 1878.2 J.mol,1K,1 at 300 K. The thermal decomposition process was investigated by means of thermogravimetric analysis and differential thermal analysis measurements in air together with infrared and X-ray powder diffraction spectra. The third-order nonlinear optical properties at 800 nm were measured by femtosecond optical Kerr gate technique by using CS2 as reference. The third-order optical susceptibility of its acetone solution at the concentration of 9.27 × 10,4 M was obtained to be 2.53 × 10,14 esu. The second-order hyperpolarizability was estimated to be 1.7 × 10,32 esu and the response time was about 226 fs. The third order nonlinear optical properties at 532 nm were investigated by using the Z-scan technique with 20 ps. It exhibited self-focusing effect and saturable absorption. The second molecular hyperpolarizability was estimated to be 8.4 × 10,32 esu. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Crystal growth, morphology, spectrographic characterization and thermal properties of 4,5-bis(benzoylthio)-1,3-dithiole-2-thione

CRYSTAL RESEARCH AND TECHNOLOGY, Issue 8 2008
Xinqiang Wang
Abstract Single crystals of 4,5-bis(benzoylthio)-1,3-dithiole-2-thione (BBDT), were grown from methylene chloride and the growth morphology was deduced by the Bravais,Friedel Donnay,Harker (BFDH) model. The grown crystals were characterized by optical absorption, infrared, Raman and X-ray powder diffraction spectroscopy. The thermal behavior of BBDT has been investigated by means of thermogravimetric analysis and differential thermal analysis measurements in air. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Photopolymerization of clay/polyurethane nanocomposites induced by intercalated initiator

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2007
Hailin Tan
Abstract An intercalated initiator was synthesized and used for preparation of clay/polyurethane nanocomposites by UV irradiation. Organoclays containing initiator groups were prepared by cationic exchange process which acted as both suitable intercalant and photoinitiator. These modified clays were then dispersed in the mixture of urethane acrylate and hexanediol diacrylate in different loading, then situ photopolymerized. Intercalated and exfoliated nanocomposite structure were evidenced by both X-ray diffraction spectroscopy and Transmission Electron Microscope. Thermal properties and morphologies of the resultant nanocomposites were also investigated. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 [source]

Crystal Shape Characterisation of Dry Samples using Microscopic and Dynamic Image Analysis

PARTICLE & PARTICLE SYSTEMS CHARACTERIZATION, Issue 4 2009
Kumar Patchigolla
Abstract A standard method to determine particle shape and size is by image analysis. This paper addresses microscopic image analysis (semi-automated) investigations of two different organic crystalline chemicals generated by batch cooling crystallisation. The results generated from microscopic image analysis were compared with data obtained by dynamic image analysis (automated) because very few contributions are available in the open literature. The chemical systems were polymorphic L-glutamic acid which crystallises into , (prismatic) or , (needle) form and the non-polymorphic mono sodium glutamate which crystallises into needles. The images from these techniques were processed to generate information on crystal shape and size. It has been observed that shape effects can distort the size obtained in size characterization studies. In this study, comparisons were made of processing time, number of crystals and accuracy between microscopic and dynamic image analysis. For representative microscopic image analysis, 5000 crystals were analysed in an average of eight hours while several hundred thousand crystals were processed using dynamic image analysis within 15 minutes. Using the parameters D10, D50, D90, span and aspect ratio for statistical comparison, it was found that the results obtained for D50 by the two techniques were comparable and in accordance with other measurements (laser diffraction spectroscopy and ultrasonic attenuation spectroscopy) even though these non-spherical particles had different orientations during measurement by the two methods. However, substantial differences in span of the distribution and aspect ratio were returned by the two techniques. [source]

Physical properties of quantum-confined europium sulfide nanocrystals

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 2 2007
M. L. Redígolo
Abstract We report the synthesis and the characterization of quantum-confined europium sulphide nanocrystals, which possess intriguing size-dependent optical and magnetic properties. Transmission electron microscopy, X-ray diffraction spectroscopy, and SQUID magnetization measurements provide evidence for the quantum-confinement effects in this monochalcogenide nanomaterial. Photoluminescence measurements indicate a blue-shifted spectrum for the nanocrystals compared with bulk europium sulphide. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Spectrally-resolved nonlinear spectroscopy of in-plane anisotropy in uniaxially-strained GaN epilayers

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 11 2005
Satoru Adachi
Abstract Spectrally-resolved four-wave mixing technique has revealed the internal structures of excitons in uniaxially strained gallium nitride films. Nonlinear response of four-wave mixing on the oscillator strength highlights the polarized excitons, and therefore allows us to map out the uniaxial strain field and the resultant anisotropic exchange splitting. Such a measurement gives a kind of crystalline analysis achieved in X-ray diffraction spectroscopy as well as information of the exciton fine structures including their temporal dynamics. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]