Materials Literature
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2-Propanol decomposition at 200 °C on magnesium oxide prepared by the hydrolysis of magnesium ethoxide (sol−gel method) is reported. With hydrochloride acid, acetic acid, or ammonia as hydrolysis alkoxide catalysts, the acidity and the selectivity to propene of the catalysts follow the sequence, MgO (HCl) > MgO (aceti…
Mathematical models that have been proposed for creep in ceramics are described. Emphasis is on models involving grain boundary motion (sliding or flow). In Lifshitz models the crystalline grains elongate with strain; the elongation results from diffusion, slip, or solution and precipitation. In Rachinger models the g…
Plasma polymerization of hexamethyldisilane ([CH 3 ] 3 SiSi[CH 3 ] 3 ) and tetramethylsilane ([CH 3 ] 4 Si) has been investigated by XPS, FTIR, solid state NMR, and plasma emission diagnostics. Thin carbosilane films and powders can be deposited by this method. Hexamethyldisilane is found to undergo glow discharge pol…
The series of tetrakis(μ-N,N‘-diarylformamidinato)dinickel(II), where the aryl is the phenyl modified with various substituent (X), is synthesized and thoroughly characterized. While both the coordination geometry and the UV−vis spectra remain essentially independent of X across the series, the one-electron oxidation…
Configurational and ligand conformational influences on the kinetics of (1)A(1) right harpoon over left harpoon (5)T(2) spin crossover in the Fe(II) complex with the novel tripodal ligand, 1,1,1-tris((N-(2-pyridylmethyl)-N-methylamino)methyl)ethane (tptMetame), have been explored. Despite having six chelate rings and…
The crystal growth rates of NH 4 H 2 PO 4, KH 2 PO 4, (NH 4 ) 2 SO 4, KAl(SO 4 ) 2 ·12H 2 O, NaCl, and glycine and the nucleation rates of KBr, KCl, NaBr·2H 2 O, (NH 4 ) 2 Cl, and (NH 4 ) 2 SO 4 were expressed in terms of the fundamental driving force of crystallization calculated from the activity of supersaturated s…
[NEt 4 ] 2 [enH] 2 [Ge 2 Se 6 ] and [NEt 4 ] 4 [Sn 4 Se 10 ] have been synthesized electrochemically by the reduction of metal chalcogen alloys in an electrolyte solution of NEt 4 Br in ethylenediamine. The structures of both compounds have been determined by single-crystal X-ray methods. [NEt 4 ] 2 [enH] 2 [Ge 2 Se 6…
The shear response of polymer brushes is explored as a function of grafting surface curvature using the Alexander−deGennes ansatz, where the free ends of the chains are localized at the tip of the brush and all tethered chains in the brush are stretched equally. Brushes adsorbed onto the concave and convex surfaces of…
Changes in shape of internally pressurized tubes caused by operating temperatures and pressures are enhanced by fast neutron irradiation. Lengths and diameters of Zr-2.5Nb pressure tubes in CANada Deuterium Uranium-Pressurized Heavy Water (CANDU-PHW) power reactors and test reactors have been monitored periodically ov…
Electron radiation induced hydrocarbon contamination can be either a problem or a useful tool in electron beam analyses and lithographies. We have used atomic force microscopy to study electron beam written contamination structures. Contamination is shown not only to arise from the primary electron beam but also from…
(Tetraphenylporphyrinato)zinc(II) covalently linked with pyridine at the ortho position of one of the four phenyl rings exists as a stable pentacoordinated complex while a temperature dependent “tail-on” and “tail-off” binding mechanism is operative for the meta-substituted derivative. The axially bound pyridine does…
Streptomyces griseus produced a certain kind of flocculating substance(s). The flocculating substance(s) could aggregate suspended kaolin particles in solution to form small floes and enables it to sediment those particles. The production of flocculating substance(s) by S. griseus was not parallel to the cell growth a…
Solid state 13 C CP/MAS studies of poly(vinyl chloride) (PVC)−bis(2-ethylhexyl) phthalate (DOP) have been carried out to elucidate the dynamics of polymer−plasticizer interaction at the molecular level. 13 C NMR spectra, spin−lattice relaxation time T 1 (C) and spin−spin relaxation time T 2 (C) were obtained for vario…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTEffect of Specimen Thickness on Crystallization RateJ. M. SchultzView Author Information Materials Science Program, University of Delaware, Newark, Delaware 19716Cite this: Macromolecules 1996, 29, 8, 3022–3024Publication Date (Web):April 8, 1996Publication History Received15 M…
Thermal conductivity of sintered silicon nitride has been improved by grain growth of β-Si3N4. β-Si3N4 containing 0.5mol% Y2O3 and 0.5mol% Nd2O3 was gas-pressure sintered at 1973 to 2473K and the microstructures and the thermal conductivities were investigated. The materials sintered at temperatures higher than 2173K…
This study examines the relationship between polymer surface conformation and colloid stability using single-stranded DNA as a model polymer and a biochemical technique called hydroxyl radical footprinting (HRF). The DNA polymer (dT40B) has a diblock copolymer architecture with an uncharged and relatively hydrophobic…
This work describes the effect of the addition of EPDM to polypropylene on the mechanical performance of EPDM/PP blends prepared in different composition ranges and mixing conditions, and evaluates the effect on the mechanical properties when controlled degraded polypropylene is added to these blends as a third compon…
Keggin-type heteropolyacids (water-soluble H 3 PMo 12 O 40, H 4 PMo 11 VO 40, and H 8 PMo 10 VCuO 40 and water-insoluble K 3 PMo 12 O 40 and H 3 - x Cs x PMo 12 O 40, x = 1, 2, 2.5, 3) deposited on highly oriented pyrolytic graphite (HOPG) surfaces were successfully imaged by scanning tunneling microscopy (STM). All o…
The esterification of aqueous lactic acid solution with methanol and its reverse reaction catalyzed by acidic cation exchange resins in the H+ form were carried out in a batch system. The inhibiting effects of water and methanol on the resins were evaluated. The experimental data were correlated by a kinetic model tha…
The thiazole orange derivative, TO-PRO-3, and its dimeric analogue, TOTO-3, bind strongly to both double- and single-stranded DNA. Both the bound and the free dye undergo efficient nonphotochemical hole burning. From the structure of the hole burned and the fluorescence line-narrowed spectra, it is concluded that ther…