Materials Literature
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Sulphate group: baryte celestine gypsum anhydrite. Carbonate group: calcite magnesite rhodochrosite siderite Smithsonite dolomite ankerite aragonite strontianite witherite cerussite Huntite nyerereite malachite and azurite. Phosphate group: apatite monazite. Halides: fluorite halite.
The perturbation of the racemic equilibrium of the D3 complexes of lanthanide (III) ions with 2, 6-pyridinedicarboxylate by a number of sugars is studied by circularly polarized luminescence spectroscopy. Various spectroscopic probes show that the addition of the chiral sugar has no observable effect on the structure…
The high‐frequency magnetic properties of strontium‐partially‐substituted Z‐type magnetoplumbite with the composition 2CoO·3Ba 1‐x .Sr x O.yFe 2 O 3 were studied using a hot‐pressing technique. The best properties were obtained for a sample hot‐pressed in oxygen, having x and y values of 0.5 and 10.8, respectively. Th…
A novel method of preparing modified chitosan films was developed. Bi- and tri-component chitosan films were prepared by blending chitosan with high molecular weight polyoxyethylene. The films were loaded with 8-hydroxy-7-iodoquinoline-5-sulfonic acid which was chosen as a model drug. The properties of the films were…
6,7-Dimethyl-8-ribityllumazine, the immediate biosynthetic precursor of riboflavin, is synthesized by condensation of 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione with 3,4-dihydroxy-2-butanone 4-phosphate. The gene coding for 6,7-dimethyl-8-ribityllumazine synthase in Saccharomyces cerevisiae (RIB4) has been clon…
Abstract The electronic structures of conjugated polymers containing methyl radicals, carbenes, and nitrogen‐based radicals coupled in various ways through benzene rings are examined, employing band‐structure calculations in the extended Hückel approximation. The structural and electronic properties of polymers with a…
The infrared spectra of a series of metal saccharinates (those of Na, Mg, Mn Fe, Co; Ni, Zn, Cd, Pb as well as mercury(II) saccharinate and chloromercury(II) saccharinate) were studied in the region of the antisymmetric and symmetric SO2 stretching vibrations [vas(SO2) and vs(SO2) hereafter]. The results concerning th…
Abstract Epoxidized natural rubber (ENR) was first precured with 3‐aminopropyltriethoxysilane (APS) by the normal compression molding technique. The resultant sheet was further subjected to moisture cure, via hydrolysis and condensation reactions, by soaking it in water. The moisture‐cured sample, when prepared under…
The luminescence properties of Cr3+ ions and the energy transfer between Cr3+ and Nd3+ ions have been studied quantitatively in yttrium aluminum garnet (YAG). The energy level diagram and the emission spectrum of 4T2→4A2 transition of Cr3+ ions were calculated in this crystal using the single-configurational-coordinat…
The dynamics of charge carrier trapping and recombination are measured as a function of ZnO cluster diameter by ultrafast pump–probe absorption spectroscopy. A finite spherical potential well model which shows good agreement with previous experimental work is employed to predict ZnO cluster diameters from absorption o…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCapped Biscalix[4]arene-Zn-Porphyrin: Metalloreceptor with a Rigid CavityDmitry M. Rudkevich, Willem Verboom, and David N. ReinhoudtCite this: J. Org. Chem. 1995, 60, 20, 6585–6587Publication Date (Print):October 1, 1995Publication History Published online1 May 2002Published…
A hyperstable (hs) variant of chicken egg-white lysozyme with enhanced thermal (delta Tm approximately +10.5 degrees C) and chemical (delta Cm for guanidine hydrochloride denaturation = +1.3 M) stabilities relative to wild-type (WT) was constructed by combining several individual stabilizing substitutions. The free en…
Photoluminescence and excitation spectra are observed for Ca(S, Se):Eu 2+ and Sr(S, Se):Eu 2+ powder phosphors at various temperatures between 4.2 and 300 K. The emission band of Ca(S 1- x Se x ):Eu 2+ at 300 K shifts almost linearly with an increase in x , from 652 nm ( x =0) to 597 nm ( x =1). In Sr(S 1- x Se x ):Eu…
Upon treatment of tribenzotriquinacene (4a) (R = H) and its centro-alkyl-substituted derivatives 4b-d (R CH3, C2H5, CH(2)Ph) with the strongly basic mixture of n-BuLi and KO(i)Pen, 2-fold deprotonation combined with (formal) elimination of RH from positions C(1)-C(10) occurs to generate tribenzacepentalene dianion 5-K…
Abstract Aspects of thermal, morphological, and rheological properties of biodegradable poly‐D(‐)(3‐hydeoxybutyrate) (PHB) blended with poly(ethylene oxide) (PEO) have been studied. Thermal properties and morphology of the blends were examined by scanning electron microscopy and differential scanning calorimetry, resp…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFactors influencing the chemical vapor deposition of oriented ZnO films using zinc acetateG. L. Mar, P. Y. Timbrell, and R. N. LambCite this: Chem. Mater. 1995, 7, 10, 1890–1896Publication Date (Print):October 1, 1995Publication History Published online1 May 2002Published in…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTReactions of B Atoms with NH3 to Produce HBNH, BNBH, and B2NCraig A. Thompson and Lester AndrewsCite this: J. Am. Chem. Soc. 1995, 117, 40, 10125–10126Publication Date (Print):October 1, 1995Publication History Published online1 May 2002Published inissue 1 October 1995https:…
Solutions of the diblock copolymer polystyrene/poly-2-vinylpyridine (PS/P2VP) in toluene were studied by cryo-transmission electron microscopy following fast freezing of a thin film of the solution in liquid nitrogen. The block copolymer forms spherical micelles which can be visualized using phase contrast microscopy.…
Currently used sterilization techniques such as ethylene oxide, gamma irradiation, and steam sterilization could introduce inadvertent consequences, especially in polymeric materials. These could have far-reaching effects on the biocompatibility of the materials. Some of these consequences are reviewed and a typical e…
We use Stark spectroscopy to examine the nature of the excited states of CdSe nanocrystallites. The Stark spectra we obtain are in the small coupling limit in which the changes induced by the electric field to the absorption spectrum are small compared to the transition linewidths. Within this limit, we theoretically…