Materials Literature
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Liquid crystals are complex organic systems exhibiting a variety of interesting phase transitions. In this paper, work is reviewed in two areas: (1) lattice dynamics of nematogenic crystals as the crystal-nematic liquid crystal phase transition is approached, and (2) vibrational spectroscopic changes at the gel-liquid…
Abstract To clarify the effects of salt and alkali on Fe 2+ and Mn 2+ equilibria in submerged soils, Maahas clay (a Haplustalf) was amended with NaCl and NaHCO 3 to give initial electrical conductivities of 5, 10, 20, and 25 mmhos/cm at 25°C and exchangeable Na percentages of 5, 10, 15, 20, and 25, respectively. The a…
Abstract Melt rheology and its time‐temperature dependence have long been known to be fundamental properties associated with satisfactory expansion characteristics in vinyl foam. Since much is known about the relationship between rheology and material variables like polymer morphology and system composition, adequate…
Kinetic results of the crystal growth and dissolution of seed crystals of calcium fluoride and magnesium fluoride, obtained conductimetrically and potentiometrically, indicate that both processes are controlled by a surface reaction mechanism. An initial reaction surge in the case of magnesium fluoride is consistent w…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTExtrinsic circular dichroism in twisted nematic mesophasesF. D. Saeva and G. R. OlinCite this: J. Am. Chem. Soc. 1976, 98, 10, 2709–2711Publication Date (Print):May 1, 1976Publication History Published online1 May 2002Published inissue 1 May 1976https://pubs.acs.org/doi/10.1…
Abstract The synthesis, processing characteristics, thermal propers, and adhesive and composite properties of polyphenvlqmnoxahnes are briefly reviewed. In addition, new high molecular weight soluble carbonate/phenylquinoxaline copolymers from the cyclopolycondensation of aromatic bis( o ‐diamines) with a bis(benzilyl…
Abstract The presence of a high temperature (> T g ) relaxation in amorphous polystyrene has been investigated further. In the previous work, 1 the techniques of differential thermal analysis (DTA) and torsional braid analysis (TBA) were employed to study polystyrene as a function of “monodisperse” molecular weight…
M e th ods of abso lut e a nd re lati ve radi a nl a nd q ua ntum effi c ie ncy m eas ure me nts a re described fo r ultrav iole t , vis ibl e , ca thod e-ray, a nd xray exc ita tio ns. Da ta o n so me s ta nd a rd lumin esce nt ma te ri a ls a re gjve n.
Abstract The dispersion of surface plasmon‐polaritons and their associated fluctuation densities and electric fields are calculated for a spatially dispersive semi‐infinite electron plasma, with, parameters appropriate to the metallic state. The model is hydrodynamic and the electron density is assumed to be uniform a…
A theoretical analysis is performed to determine the intrinsic variables which affect the green strength of ideal dry bodies held together by organic binders. The parameters which influence strength (i.e. types of bonds formed, the amount of binder, the density of the ceramic, the packing density, and the cohesive or…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTChanges in lysozyme due to reactions with peroxidizing methyl linoleate in a dehydrated model systemJoseph Kanner and Marcus KarelCite this: J. Agric. Food Chem. 1976, 24, 3, 468–472Publication Date (Print):May 1, 1976Publication History Published online1 May 2002Published i…
The citric acid‐hydrogen peroxide‐water system has been developed for preferential etching of through photoresist masks. Etching rates depend strongly on the composition of the solution and on the crystal orientation of , with the rates in the order (111)B > (100) > (111)A. Flat‐bottomed holes were obtained for all co…
Expressions are derived for the estimation of the variance and the covariance in the deformation electron density qo/k - qc, for a centrosymmetric crystal structure. The uncertainty in the calculated density qc depends strongly on the distance to the nuclei. The uncertainty in the observed density qo is fairly constan…
Light scattering in antiferromagnetic crystals CoO, MnO, and $\ensuremath{\alpha}\ensuremath{-}\mathrm{MnS}$ has been studied experimentally in the temperature range from 6 to 300 K. The spectra showed peaks associated with one-magnon and two-magnon excitations. These structures diminished with increasing temperature,…
The dynamic critical exponents of classical liquids are studied on the basis of the mode coupling theory. The shear viscosity for the spatial dimensionality between two and four exhibits the weak power law divergence at a critical point, which was briefly reported in a previous paper. The non-Markoffian effects and th…
An anisotropic three-dimensional random walk model is developed and used to describe the frequency dependence of proton spin–lattice relaxation rates in several TCNQ salts. The triplet exciton system (φ3AsCH3) (TCNQ)2 at 145 °K is shown to display two-dimensional diffusive behavior. Measurements of the proton relaxati…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTChemistry of the macrocyclic cobalt(II) complex, [Co(C22H22N4)]. Reactions with halogens, molecular oxygen, alkynes, and nitrilesMarvin C. Weiss and Virgil L. GoedkenCite this: J. Am. Chem. Soc. 1976, 98, 11, 3389–3392Publication Date (Print):May 1, 1976Publication History P…
Abstract When benzene or phenol are adsorbed on smectite containing Fe(III) or Cu(II) on the exchange complex, higher molecular weight products are formed. Evidence for these products is provided by mass spectroscopy. In the case of benzene most of the reaction products cannot be attributed to coupled benzene rings, w…
The first series of ferrocene derivatives exhibiting mesomorphic properties (substituted N-(p-benzoyloxybenzylidene) anilines la and 1b) has been synthesized for application in Mössbauer spectroscopy.
The capacitance-voltage ( C - V ) and forward biased current-voltage ( I - V ) characteristics, electroluminescence (E.L) and photovoltaic effect of GaSe–SnO 2 heterojunction diodes are measured. SnO 2 layer is deposited on the c -plane of GaSe by using the spray method. The C - V and I - V characteristics of these di…