Materials Literature
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Oral administration of bergenin and norbergenin, two isocoumarins, isolated from the leaves and roots of Flueggea microcarpa and luvangetin, a pyranocoumarin isolated from the seeds of Aegle marmelos Correa, showed significant protection against pylorus-ligated and aspirin-induced gastric ulcers in rats and cold restr…
The author presents a theory of color symmetry applicable to the description and classification of periodic as well as quasiperiodic colored crystals. This theory is an extension to multicomponent fields of the Fourier-space approach of Rokhsar, Wright, and Mermin. It is based on the notion of indistinguishability and…
We show here a general model of phase separation in isotropic condensed matter, namely, a viscoelastic model. We propose that the bulk mechanical relaxation modulus that has so far been ignored in previous theories plays an important role in viscoelastic phase separation in addition to the shear relaxation modulus. In…
The interaction of crystal violet (CV) with halide, halate ions, and pyridine and the interaction of CV with colloidal silver surface have been studied by surface-enhanced Raman spectroscopy (SERS) with near-infrared (NIR) excitation. Cl -, Br -, I -, and BrO 3 - ions as well as pyridine give rise to a large enhanceme…
Differential scanning calorimetry (DSC) is one of the most widely used technique for measuring crystallinity in the polymer industry. The major source of error in the crystalline index (CIDSC) of low crystallinity polymeric articles, is the development of further crystallinity during the DSC scan. Although, this type…
Large-area high density patterns of quantum dots with a diameter of 200 nm have been prepared from a series of four Zn_{0.93}Mn_{0.07}Te/ZnTe multiple quantum well structures of different well width (4 nm, 6 nm, 8 nm and 10 nm) by electron beam lithography followed by Ar+ ion beam etching. Below-bandgap photomodulated…
The linear muffin-tin orbital method combined with density functional theory (local approximation) and the semiempirical method of the intermediate neglect of the differential overlap (INDO) based on the Hartree-Fock formalism are used for the study of the $F$ centers (O vacancy with two electrons) in cubic and orthor…
Thin oxide films (from one to tens of monolayers) of SiO2, MgO, NiO, Al2O3, FexOy, and TiO2 supported on refractory metal substrates have been prepared by depositing the oxide metal precursor in a background of oxygen (ca 1 x 10(-5) Torr). The thinness of these oxide samples facilitates investigation by an array of su…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTCellulose Microcrystal Film of High Uniaxial OrientationNishiyama Yoshiharu, Kuga Shigenori, Wada Masahisa, and Okano TakeshiView Author Information Laboratory of Structural Biopolymers, Department of Biomaterial Sciences, Graduate…
Protein-protein contacts in monomeric protein crystal structures have been analyzed and compared to the physiological protein-protein contacts in oligomerization. A number of features differentiate the crystal-packing contacts from the natural contacts occurring in multimeric proteins. The area of the protein surface…
The flexural strength of porous Si 3 N 4 ceramics with a variety of microstructures and porosities were evaluated, and the effect of microstructure on the flexural strength was investigated to obtain machinable Si 3 N 4 ceramics having both high strength and high thermal shock resistance. Porous Si 3 N 4 having three…
A mechanistic investigation on the photocatalytic reduction of CO 2 with hexagonal CdS nanocrystallites prepared in N, N -dimethylformamide (DMF) was carried out from the standpoint of surface structures of the nanocrystallites. A remarkable increase of photocatalytic activity could be achieved by addition of excess C…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTChemistry Induced by Hydrodynamic CavitationKenneth S. Suslick, Millan M. Mdleleni, and Jeffrey T. RiesView Author Information Department of Chemistry University of Illinois at Urbana-Champaign 601 South Goodwin Avenue, Urbana, Illinois 61801 Cite this: J. Am. Chem. So…
Two effective computational approaches for the study of magnetic exchange interactions in large molecules are discussed and tested on a number of model systems, namely, broken-symmetry (BS) and single-determinant (SD) models. Both methods are based on the density functional theory (DFT) but exploit different approxima…
ADVERTISEMENT RETURN TO ISSUEPREVFeaturesNEXTPeer Reviewed: Boron-Doped Diamond Thin-Film Electrodes Diamond thin films could be an electrochemist's best friend. Jishou Xu, Michael C. Granger, Qingyun Chen, Jerzy W. Strojek, Tedd E. Lister, and Greg M. SwainCite this: Anal. Chemi. 1997, 69, 19, 591A–597APublication Da…
Thermogravimetric data for the decomposition of ammonium dinitramide (ADN) have been obtained under isothermal and nonisothermal conditions in order to determine the efficacy of different methods for analyzing the kinetics of solid-state reactions. A widely used model-fitting method gives excellent fits to the experim…
The crystallographic origins leading to the formation of polymer single crystals with highly unusual triangular shapes are analyzed. Triangular crystals are obtained: (a) for stereocomplexes of poly( l -lactide) (PLLA) and poly( d -lactide) (PDLA) crystallizing in a trigonal unit cell with R 3 c (or R -3 c ) symmetry.…
The oxidation of hydrogen on Ni/yttria‐stabilized zirconia (Ni/YSZ) is studied by impedance spectroscopy. The active thickness obtained is 20 μm or less. Conditions such as temperature, anodic overvoltage, electrode potential, and partial pressure are varied. Three distinct arcs are identified in impedance spectra, re…
Helical structures were confirmed for both the SmA b and SmBlue phases of banana-shaped molecular systems from observations of the microscopic fringe pattern and the selective reflection of blue color, respectively. X-ray and optical microscopy indicate that the helical axes in the SmA b and SmBlue phases are normal a…
The synthesis, characterization, thermal stability, optical spectroscopic, electronic structure, and second-order nonlinear optical (NLO) response of a series of donor−acceptor bis(salicylaldiminato)nickel(II) Schiff base complexes and the free ligand precursors are reported. The effect of the metal center in such com…