Materials Literature
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The expanded Hansen method was tested for determination of the solubility parameters of two non-steroidal anti-inflammatory drugs, naproxen and sodium diclofenac. This work describes for the first time the application of the method to the sodium salt of a drug. The original dependent variable of the expanded Hansen me…
Coprecipitates, Ni(OH)2 + 2Fe(OH3, were milled in a planetary mill, using an agate bowl and balls (99.9% SiO2), and then heated at a maximum temperature of 573 or 773 K. The Mossbauer spectra at 298 K of the ball-milled samples (not heated) showed the superposition of two quadrupole doublets. After heating at 573 K, t…
Using the Gibbs description of an interphase, the necessary conditions for equilibrium of a closed, two-phase fluid system in the presence of gravity are the Laplace and Young equations and a condition on the chemical potentials. The last condition has been neglected in all previous examinations of contact angles in a…
Supramolecular multilayered ferromagnets in which metal layers are interleaved with iminonitroxide benzoate radical anions have been synthesized and characterized by the authors. The structure of these novel compounds (see cover) consists of stacks of alternating organic–inorganic layers. Long-range ferromagnetism is…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Chemistry behind Carbonless Copy PaperMary Anne White View Author Information Dalhousie University, Department of Chemistry, Halifax, Nova Scotia B3H 4J3, CANADACite this: J. Chem. Educ. 1998, 75, 9, 1119Publication Date (Web):September 1, 1998Publication History Receive…
ESR measurements have been carried out on Mn ions in PbTiO 3 ceramics. Mn ions in the PbTiO 3 ceramics are incorporated at Ti 4+ sites with mixed valence states of Mn 2+ and Mn 4+ . The proportion of Mn 2+ ions is the highest for the calcined powder and changes during the firing process. After the firing it decreases…
The effect of OH bonds on the optical absorption and persistent spectral hole burning (PSHB) properties was quantitatively analyzed in ${\mathrm{Eu}}^{3+}$-doped $\mathrm{BaO}\ensuremath{-}{\mathrm{P}}_{2}{\mathrm{O}}_{5}$ glasses. Glasses were prepared by melting the raw material at 600--$800\ifmmode^\circ\else\textd…
We present an experimental investigation of the influence of interfacial anisotropy on the cellular growth patterns observed in directional solidification of the ${\mathrm{CBr}}_{4}\ensuremath{-}8\mathrm{}\mathrm{mol}%$ ${\mathrm{C}}_{2}{\mathrm{Cl}}_{6}$ alloy at pulling velocities less than twice the cellular-thresh…
Conductivity measurements were performed on bundles of single-walled carbon nanotubes with the aid of a scanning tunneling microscope (STM). Semimetallic current-voltage (I-V) characteristics generally indicated the bundles to be electronically similar to graphite. However, by moving the STM tip along the length of th…
Ab initio molecular orbital calculations on clusters of atoms consisting of various types of silica rings (3-, 4-, 5-, and/or 6-membered rings) that can be found in vitreous silica are performed at the Hartree-Fock (HF) level. We optimized the geometries of the clusters at the HF/6--31 G $(d)$ level; the average Si-O,…
A novel Brownian dynamics method has been developed to simulate the properties of polymer brushes under shear. Simulations of 100 chains with a chain length of 100 segments have been carried out for a range of shear rates. Compared to previous methods there is a substantial saving in computational time as the self-con…
New photolabile protecting groups have been found in the 2-(2-nitrophenyl)ethoxycarbonyl and the 2-(2-nitrophenyl)ethylsulfonyl group, respectively. The influence of substituents at the phenyl ring as well as the side-chain has been investigated regarding the photolysis rates on irradiation at 365 mn. β-Branching in t…
Abstract To explain the crystallization behaviour and phase relationships of precursor derived Si‐B‐C‐N ceramics, In ( p N 2 )‐ T diagrams were calculated. The results can be used to optimize the chemical composition and the physico‐chemical conditions for heat treatment. Stabilization of specific phase assemblages re…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTSynthesis of the First Expanded Carbaporphyrinoid by the “4 + 1” ApproachTimothy D. Lash and Daniel T. RichterView Author Information Department of Chemistry Illinois State University Normal, Illinois 61790-4160 Cite this: J. Am. Chem. Soc. 1998, 120, 38, 9965–9966Publ…
The miscibility and crystallization behavior of binary crystalline blends of poly(butylene terephthalate) [PBT] and polyarylate based on Bisphenol A isophthalate [PAr(I-100)] have been investigated using differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD). Both polymers were able to crystal…
Differential scanning calorimetry (DSC) and X-ray diffraction analysis were performed to study the multiple melting behavior and crystal forms of neat syndiotactic polystyrene (s-PS) in comparison with its miscible blends with amorphous atactic polystyrene (a-PS) or poly(2,6-dimethyl-p-phenylene oxide) (PPO). For neat…
Grain boundaries in model ZnO-Bi2O3 and ZnO-Bi2O3-CoO varistors and a commercial multicomponent varistor have been characterized by high-resolution electron microscopy (HREM) and scanning transmission electron microscopy (STEM), in order to determine the relationship between Bi grain boundary segregation and formation…
New liquid crystals consisting of non-chiral, banana shaped molecules are investigated by the generation of the second harmonic (SHG) of an optical wave. The temperature and electric field dependence of the SH activity of the apparent thermodynamic phases of several homologues are studied and first quantitative values…
We present large-scale molecular dynamic simulations of microcrack growth in -iron based on an N -body potential model which gives a good description of defect energetics, anisotropic elasticity and phonon frequency spectra. We demonstrate dynamic overshoot of a pre-existing microcrack under impact loading. We show th…
We study a series of the perovskite manganite compounds ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3}$ closely spaced in doping near $x=0.50$ where the ground state undergoes a doping-dependent metal-insulator transition (MIT) from a metallic to a charge-ordered state. A significant difference i…