Materials Literature
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Abstract An investigation is made of the energy spectra of A and B excitons in CdS by measuring the transmission and reflectivity of very thin highly perfect crystals at 1.8 K. The excited states of both series follow hydrogen‐like series in a good approximation yielding different Rydberg's R = (28 ± 0.4) and R = (31.…
The compositional and structural changes on surfaces that affect the durability of soda-limesilica glasses are discussed. The book begins with a general review of corrosion and weathering phenomena in glass which is followed by a review of the applicable surface analytical techniques (scanning electron microscopy, ene…
Carbon monoxide, oxygen and hydrogen were found to be chemisorbed on dehydrated AgA zeolites. This was investigated in detail using volumetric sorption and temperature programmed desorption techniques. Also i.r. and mass spectrometry were used to characterize the solid and the desorbed molecules.It was found that as a…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEffects of electron-withdrawing substituents on the electrochemical oxidation of porphyrinsA. Giraudeau, H. J. Callot, and M. GrossCite this: Inorg. Chem. 1979, 18, 1, 201–206Publication Date (Print):January 1, 1979Publication History Published online1 May 2002Published inis…
Gold has been supported upon SiO2 and γ-Al2O3 using an impregnation technique and HAuCl4 solutions. The severity of the conditions required to effect the reduction/decomposition of the acid to metallic Au upon the support decreased and the activity per unit weight of metal in the hydrogenation of pent-1-ene at 373 K i…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDerivatives of heteropolyanions. 1. Organic derivatives of W12SiO404-, W12PO403-, and Mo12SiO404-W. H. KnothCite this: J. Am. Chem. Soc. 1979, 101, 3, 759–760Publication Date (Print):January 1, 1979Publication History Published online1 May 2002Published inissue 1 January 197…
Manganese(III) forms many high spin d4 porphyrins, for which pyridyl, N-methylpyridyl, sulphonic acid and carboxylic acid and carboxylic acid functions act as water solubilising groups. Reduction with dithionite yields the corresponding manganese(II) porphyrin. Both oxidation states have been clearly identified by e.p…
Description The ASTM series on Engineering Dielectrics is devoted to a comprehensive presentation of topics related to electrical insulating materials that concern their dielectric properties, their use, and evaluation for application for electrical power and communication apparatus structures and devices. The first v…
A three-parameter description of optical fiber material dispersion is proposed which fits the available data and reveals the key roles played by bond length, lattice structure, chemical valence, average energy gap, and atomic mass. Using broadly applicable trends in electronic and phonon oscillator strengths, simple e…
It is shown that the mechanism of the electronic conduction due to variable-range hopping in the Anderson localized states gives rise to a large negative magnetoresistance, particularly in the vicinity of the metal-nonmetal transition. This result is mainly caused by an exponential dependence of the hopping rate on th…
Abstract A series of radiation‐grafted hydrogels with water contents ranging from 10% to 90% have been prepared. When evaluated by the vena cava ring test, increasing amounts of adherent thrombus were found in rings with lower graft water contents. Using a baboon arteriovenous shunt evaluation system, platelet thrombo…
Abstract The high‐strength, high‐modulus Kevlar 49 fiber is widely used today because of its superior properties. In this paper, we discuss the fundamental physicochemical nature of the commercial fiber. It is an extended chain polymer, poly( p ‐phenylene terephthalamide), which is highly crystalline. Extensive analys…
Even though the average molecular direction in smectic A phases is perpendicular to the smectic planes, most molecules in these phases have rather large tilt angles because the orientational order parameter S in all smectic A phases is significantly less than unity. This molecular tilt inherent to all A phases account…
A three-sublattice analysis of ${M}^{2+}{{\mathrm{Fe}}_{2}}^{3+}{\mathrm{O}}_{4}$ ($M={{\mathrm{Li}}_{0.5}}^{+}{{\mathrm{Fe}}_{0.5}}^{3+}, {\mathrm{Mn}}^{2+}, {\mathrm{Fe}}^{2+}, {\mathrm{Co}}^{2+}, {\mathrm{Ni}}^{2+}, {\mathrm{Cu}}^{2+}$) spinel ferrites based on the molecular-field approximation has been used to obt…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTRigid Backbone Polymers. 2. Polyisocyanates and Their Liquid-Crystal BehaviorShaul M. AharoniCite this: Macromolecules 1979, 12, 1, 94–103Publication Date (Print):January 1, 1979Publication History Published online1 May 2002Published inissue 1 January 1979https://doi.org/10.…
Abstract The reactive Al pool in selected Ultisols, Oxisols, and Histosols from Africa, South America, and North Carolina was estimated by extraction with 1 N CuCl 2 . The Al‐saturated clay minerals with and without interlayered hydroxy‐Al were used to compare the extractability of Al by 1 N CuCl 2 and 1 N KCl. The 1…
The two structural phase transitions in the perovskite layer structure compound (C10H21NH3)2CdCl4 at Tc1=35 °C and Tc2=39 °C have been studied by x‐ray diffractional, calorimetric and dielectric measurements, proton NMR spin–lattice relaxation and second moment investigations, 35Cl and 14N quadrupole resonance spectro…
I-Materials.- 1 Introduction.- 2 Styrenic Thermoplastic Elastomers.- 3 Thermoplastic Polyolefin Elastomers.- 4 Elastomeric Alloy Thermoplastic Vulcanizates.- 5 Single Phase Melt Processible Rubber.- 6 Copolyester Thermoplastic Elastomers.- 7 Thermoplastic Polyurethane Elastomers.- 8 Polyamide Thermoplastic Elastomers.…
OBJECTIVE: We introduce an RGD (Arg-Gly-Asp)-containing peptide of collagen IV origin that possesses potent cell adhesion and proliferation properties. MATERIALS AND METHODS: In this experimental study, the peptide was immobilized on an electrospun nanofibrous polycaprolactone/gelatin (PCL/Gel) hybrid scaffold by a ch…
The strength characteristics of annealed brittle surfaces impacted with sharp particles were studied. A theory of the degradation process is constructed in three steps: (1) A sharp particle delivers an impulsive load to the target surface via a plastic contact; (2) the contact loading initiates and propagates median c…