Analysis Measurements (analysis + measurement)

Distribution by Scientific Domains


Selected Abstracts


Growth, structure and thermal properties of CuAlxGa1-xSe2 alloys

CRYSTAL RESEARCH AND TECHNOLOGY, Issue 10 2006
J. Castro
Abstract Ingots of the CuAlxGa1-xSe2 (0 , x , 1) alloys system were prepared by direct fusion of the stoichiometric mixture of the elements. The analysis of X-ray Powder Diffraction data showed the presence of one single phase with chalcopyrite tetragonal structure at room temperature for all the studied compositions. The lattice parameters, a and c, and the bond lengths were calculated. The phase transition temperatures were obtained by the onset method from Differential Thermal Analysis measurements performed on samples sealed in evacuated quartz ampoules. Fusion or transition enthalpies were determined from the area of the corresponding DTA peak. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


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]


Synthesis and characterization of imine-coupled polyphenols containing carbazole units

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2009
smet Kaya
Abstract Imine coupled phenolic monomers containing carbazole unit were synthesized in four steps. The monomers were polymerized via oxidative polycondensation by air as oxidant in an aqueous alkaline medium at 50°C. The structures of compounds were confirmed by ultraviolet,visible (UV,vis), Fourier transform infrared, and 1H- and 13C-NMR techniques. The conductivity measurements of these polymers were made by the four-point probe technique and iodine was used as doping agent. The highest occupied molecular orbital, the lowest unoccupied molecular orbital, and electrochemical and optical band gap values were calculated by the results of the UV,vis and the cyclic voltammetry measurement, respectively. The number-average molecular weight, weight-average molecular weight, and polydispersity index values were determined by the size exclusion chromatography technique. Also, thermal behavior of these polymers was determined by thermogravimetric/differential thermal analysis measurements in a N2 atmosphere between 20 and 1000°C. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source]


Synthesis and characterization of high thermally-stable and good soluble PVK-based polymers with perylene moiety

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2008
Jianli Hua
Abstract Three new poly(N -vinylcarbazole) (PVK)-based copolymers containing N -(n -butyl)- N -ethyl-1,6,7,12-tetra-(4- tert -butyl-phenoxy)-3,4,9,10-perylene tetracarboxylic bisimides were successfully synthesized by partially formylated by the standard Vilsmeier reaction, and the formyl groups of high reactivity are condensed with cyanoacetylated perylene to afford PVK-based polymers. The copolymers containing different percentage of perylene were obtained through the percentage of cyanoacetylated perylene unit being controlled by the initial feed ratio. The structures and properties of three copolymers were characterized and evaluated by FT-IR, NMR, UV,vis, FL spectroscopy, gel permeation chromatography, and thermogravimetric analysis measurements. The polymers were highly soluble in conventional solvents such as toluene, CHCl3, THF, DMF etc., and they were thermally stable up to 442,445°C. Three copolymers have emission spectra with characteristic features of the perylene unit, and fluorescence quantum yields of polymers are higher than that of perylene bisimide, which may be caused by singlet,singlet energy transfer from PVK backbone to perylene in the polymers. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source]


The influence of Metal Dusting on gas reactions

MATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 4 2004
A. T. W. Kempen
Abstract Gas composition analysis measurements have been performed in the outlet gas stream of a laboratory metal dusting test furnace in order to study the influence of metal dusting on gas reactions. This analysis has shown that carbon deposition is associated with metal dusting, i.e. the material most severely attacked by metal dusting, catalyses the formation of carbon to the largest extent. Also, metal dusting has not been seen to influence the methanation reactions. A kinetic model has been used to interpret the obtained data with respect to the catalytic activity of several high temperature materials showing that the catalytic activity of the material can vary by orders of magnitude for different reactions. [source]


Two solid phases of pyrimidin-1-ium hydrogen chloranilate monohydrate determined at 225 and 120,K

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 3 2010
Kazuma Gotoh
The crystal structures of two solid phases of the title compound, C4H5N2+·C6HCl2O4,·H2O, have been determined at 225 and 120,K. In the high-temperature phase, stable above 198,K, the transition temperature of which has been determined by 35Cl nuclear quadrupole resonance and differential thermal analysis measurements, the three components are held together by O,H...O, N...H...O, C,H...O and C,H...Cl hydrogen bonds, forming a centrosymmetric 2+2+2 aggregate. In the N...H...O hydrogen bond formed between the pyrimidin-1-ium cation and the water molecule, the H atom is disordered over two positions, resulting in two states, viz. pyrimidin-1-ium,water and pyrimidine,oxonium. In the low-temperature phase, the title compound crystallizes in the same monoclinic space group and has a similar molecular packing, but the 2+2+2 aggregate loses the centrosymmetry, resulting in a doubling of the unit cell and two crystallographically independent molecules for each component in the asymmetric unit. The H atom in one N...H...O hydrogen bond between the pyrimidin-1-ium cation and the water molecule is disordered, while the H atom in the other hydrogen bond is found to be ordered at the N-atom site with a long N,H distance [1.10,(3),Å]. [source]


Fresh-frozen vs. embalmed bone: is it possible to use formalin-fixed human bone for biomechanical experiments on implants?

CLINICAL ORAL IMPLANTS RESEARCH, Issue 5 2009
Ayhan Cömert
Abstract Purpose: As formalin is an extremely reactive electrophilic chemical that reacts with tissues, the purpose of this study was to explore whether formalin fixation could potentially alter the mechanical properties of bone tissue and have an effect on the primary stability measurements of implants. Material and methods: ,3.3 × 8 mm, ,4.1 × 8 mm, and ,4.8 × 8 mm implants were placed on sockets prepared into the anterior surface of the radius of two fresh-frozen human cadavers. The insertion torque of each implant was quantified using a strain-gauged torque-wrench connected to a data acquisition system at a sample rate of 10 KHz, and resonance frequency analysis measurements were also undertaken for each implant. The cadavers were then subjected to embalment with 10% formalin for 3 months, and the same experiments were undertaken on the contra lateral radius of the cadavers. Results: The insertion torques before and after chemical fixation were similar for ,3.3 mm (P>0.05), and higher values were obtained for ,4.1 mm and ,4.8 mm implants after chemical fixation (P<0.05). The resonance frequency analysis values before and after chemical fixation were similar for all implants (P>0.05). Conclusions: Implants have higher insertion torque values in formalin-fixed bone than fresh-frozen human bone, but similar implant stability quotients in both cases. The insertion torque technique can detect the difference between formalin-fixed and fresh-frozen human bone, but resonance frequency analysis cannot. [source]