Magnetic ordering induced Raman scattering in FePS3 and NiPS3 layered compounds
Abstract
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Photolytic rearrangement of metronidazole to N-(2-hydroxyethyl)-5-methyl-1,2,4-oxadiazole-3-carboxamide. Crystal structure of its 4-nitrobenzoate derivative
U.v. irradiation of metronidazole (1-hydroxyethyl-2-methyl-5-nitroimidazole) in oxygen-free aqueous solution leads to rearrangement via a labile intermediate to N-(2-hydroxyethyl)-5-methyl-1,2,4-oxadiazole-3-carboxamide. The structure has been verified by crystallographic assignment of a 4-nitrobenzoate derivative.
Cultured pearls-production and quality
Pearls have a premium on quality. The quality \ndifferences ate so subtle and discrete that even professionals \nin the pearl trade can make wrong judgements. \nThe value of pearls, on the one hand, is decided on bulk \nby weight and, on the other, by the quality of individual \npearls. Being a bio…
Phase transition altering the symmetry of topological point defects (hedgehogs) in a nematic liquid crystal
A phase transition between states of a nematic liquid crystal in a spherical drop was detected experimentally and described theoretically. This transition took place between states which differed solely in respect of the symmetry of a topological point defect (hedgehog) at the center of the drop. The transition occurr…
AC Field and Frequency-Controlled Electrooptic Switching Using A Pyrimidine Type Ferroelectric Liquid Crystal
The physical contrast ratios (CRs) of an electrooptic switching element using a pyrimidine type ferroelectric liquid crystal (LC) was investigated. The electrooptic response of the element to the AC square wave voltages was shown to be strongly dependent both on the amplitudes and frequencies of the applied voltages.…
Pitting Corrosion Behavior of Alloy 800 in Chloride-Sulfate Media
Potentiodynamic polarization techniques were used to determine characteristic pitting potentials for Alloy 800 in chloride and chloride-sulfate media. The effect of chloride concentration in the range of 0.001 to 1 M was investigated. Decreasing chloride concentrations resulted in noble shifts of the critical nucleati…
Structure of fibrous cellulose acetate: X‐ray diffraction, positron annihilation and electron microscopy investigations
Abstract X‐ray diffraction, positron annihilation, electron microscopy and bulk density measurements are reported as a function of the degree of acetylation for a linters cotton. Heterogeneous reaction proceeds with a retention of ordered structure in the fibers. Substitution does increase the extent of disorder but i…
Observations on the Reactions of Isocyanoacetane Esters with Isothiocyanates and Isocyanates
m e reactions of the w t a l s a l t s of a-isocyanoacetate e s t e r s with isothiocyanates and isccyanates =re examined.me e f f e c t s of mrliQing the reaction paramstem on t h e altcm of the reaction (Schem?I1 of methyl a-isocyanoacetate ( G I with phew1 isothiocyanate (21 have been studied, thus providing elhawe…
The influence of surface topography on the x‐ray intensity in electron microprobe analysis (EDS/WDS)
Abstract Copper surfaces were ground or polished to various surface roughnesses and analysed by WDS and EDS. Both K and L photons were analysed at the accelerating voltages 5, 15 and 45 kV. The influence of topography on the K‐peak intensity was negligible, while the L‐peak intensity was rather sensitive to the surfac…
The Determination of the Frank Elastic Constant for Twist Deformation of 4′-n-pentyl-4-cyanobiphenyl (5CB) Using a Conoscope
The Frank elastic constant for twist deformation k 22, has been determined as a function of temperature for 5CB and compared with values cited in literature. The results, together with the values of the elastic constants for splay, k 11, and bend, k 33, which have been measured recently by Bradshaw et al. and the valu…
Marine Atmospheric Corrosion Museum Report on the Performance of Thermal Spray Coatings on Steel
Corrosion control is usually implemented by alloy upgrading or material substitution, environmental modification or providing a protective barrier or sacrificial surface or both. Historically, the coatings approach has been the predominant first choice based on initial economics. Current and emerging coating technolog…
Crystal structures and properties of [Au(phen){(CN) 0.92 Br 0.08 } 2 ]Br and [Au(phen)(CN){(CN) 0.82 Br 0.18 }]·0.5trans-[Au(CN) 2 Br 2 ]·0.5Br·phen (phen = 1,10-phenanthroline) obtained by disproportionation of five-co-ordinate bromodicyano(1,10-phenanthroline)gold( III ). Two examples of secondary co-ordination and CN/Br disorder in square-planar gold( III ) complexes
The disproportionation of neutral five-co-ordinate [Au(phen)(CN)2Br](phen = 1,10-phenanthroline) in dimethylformamide (dmf) gives a conducting solution from which two charged species, [Au(phen){(CN)0.92Br0.08}2]Br (1) and [Au(phen)(CN){(CN)0.82Br0.18}]·0.5trans-[Au(CN)2Br2]·0.5Br·phen (2), have been separated and char…
Thermomechanical Mismatch in Ceramic‐Fiber‐Reinforced Glass‐Ceramic Composites
The thermomechanical relationship between mullite and a lithium aluminosilicate (LAS) glass‐ceramic has been studied by a technique of bimaterial dilatometry. The viscoelastic behavior of LAS was found to result in a temperature T rvsl below the glass‐transformation temperature T g at which the interfacial stresses be…
Effect of Raw Materlals and Processing on the Quality of Granules Prepared from Microcrystalline Cellulose-Lactose Mixtures
Wet granulation, using lactose as an excipient, is widely used in the pharmceutical industry. The use of micro-crystalline cellulose, as part of the excipient, may offer several advantages. The purpose of this work is to investigate the effect of ingredients and processing variables on granule quality. For these studi…
Kinetic properties of two-dimensional metal systems
The two-dimensional degenerate Fermi gas of electrons interacting with phonons is considered. The basic mechanisms of momentum relaxation in such a system, associated with electron-phonon, phonon-phonon and electron-electron collisions, are shown to be qualitatively different from similar mechanisms in an ordinary thr…
Correlation of Zero-Field Splittings and Site Distortions. IX. Fe3+ and Cr3+ in β -Ga2O3
EPR of Fe 3+ in distorted tetrahedral sites in single crystals of β-Ga 2 O 3 has been measured for the first time, and the second-order zero-field splitting (ZFS) parameters and principal axes directions were determined. The data for the sixfold coordinated Fe 3+ are in good agreement with results from the literature.…
The Crystal and Molecular Structure of Heavy Lanthanoid(III) Chloroacetates in the Hydrated Form, [M3ClCH2CO2)9(H2O)4]n·nH2O (M=Gd, Dy, Er, and Yb)
Abstract The crystal and molecular structures of the chloroacetato complexes of gadolinium(III), erbium(III), and ytterbium(III) indicated in the title were determined by the single-crystal X-ray diffraction method. In addition to these three complexes, the isomorphous dysprosium(III) salt was also obtained. Their che…
Mechanistic aspects of the thermal stabilisation of PVC by organotin compounds
Abstract When subjected to heat and mechanical shear PVC decomposes via the elimination of HCl. This process is controlled most efficiently by the use of organotin stabilisers. This review outlines the basic degradation/stabilisation mechanisms which are involved in these processes. The organotin compounds of most com…
Hydrazine reduction of transition-metal oxides
The surface interactions of the thermodynamically stable oxides of the firstrow transition metals with hydrazine, N2H4, have been assessed by X-ray photoelectron spectroscopy (X.p.s.), and the observed reactivity explained on the basis of the oxides' thermodynamic and acid–base properties. Microgravimetry, transmissio…
Efficient synthesis of acetone from ethanol over ZnO–CaO catalyst
ZnO–CaO (molar ratio 9 : 1) exhibited a high catalytic activity (100% conversion) and selectivity (91%) for formation of acetone from ethanol at 673 K.