Materials Literature
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Photoelectron diffraction and Auger-electron diffraction studies to date have involved the study of the elastically scattered or ``no-loss'' features in spectra. In this work, we consider the diffraction patterns associated with inelastically scattered electrons in plasmon satellites. Although very similar in most pea…
Electro-optic properties of thin polymeric films can be studied by incorporating the films into the spacer layers of transmission-mode Fabry–Pérot devices formed using metal mirrors. The metal mirrors, which also serve as electrodes, are used for the application of an electric field for poling the polymeric material a…
Sound velocity, υ s , has been measured to examine the thermodynamics of structural transitions in the liquid Se-Te system. The isothermal compressibility, κ T , deduced from υ s together with the thermal expansion coefficient, α P , the constant pressure specific heat, C P , and the density shows a broad maximum when…
The detailed quantitative speciation of phosphorus and selenium microstructures in phosphorus-selenium glasses is derived from combined $^{31}\mathrm{P}$ spin-echo and magic-angle-spinning NMR experiments. The results illustrate that the structure of these glasses differs from the chemically ordered or clustered struc…
Abstract Differential scanning calorimetry (DSC) and in situ small‐angle x‐ray scattering (SAXS) indicate that in an α ω‐methoxy‐poly(ethylene oxide) (MPEO) fraction (MW 3000) a transient nonintegral folding (NIF) crystal initially forms during crystallization throughout a wide range of crystallization temperatures. S…
Evidence for interaction between the N-N pair and interstitial O in N-doped Czochralski silicon has been presented by studying the annealing behavior of the corresponding IR absorption bands.
Diamond powders with grain diameters up to 0.3 μm were obtained by CO2 -laser-induced decomposition of C2H4 at low pressures and temperatures. C2H4 or mixtures of C2H4, H2, and SiH4 were irradiated in a gas-flow reactor with the 10P14 line (10.532 μm) of a grating-tunable CO2 laser with 50-W cw output power. Solid pro…
Selectively deuterated glycerol has been subjected to 2 H-NMR spin-lattice relaxation and quasi-elastic neutron scattering experiments. The measurements yield relaxation rates and a non-Gaussian Q -dependence of the Debye-Waller factor which are different for the two hydrogen sites. The data analysis shows that below…
Dense fluids of biaxial hard convex bodies exhibit a phase transition from an isotropic to a nematic (I–N) liquid–crystalline state. In the Onsager theory, the I–N transition is attributed to the tendency of pairs of molecules to minimize their excluded volume (or second virial coefficient, B2 ). In the present work,…
Measurements of the dynamics of NH(X3∑−, v =1–3), created in electron-irradiated N2/H2 and Ar/N2/H2 mixtures, have been performed. Time-resolved Fourier spectroscopy was used to observe NH(v→v–1) vibrational fundamental band emission. Time-dependent populations were then determined by spectral fitting. Subsequent kine…
Abstract The complex polymorphic behavior of syndiotactic polystyrene (s‐PS) in melt‐crystallized samples is altered by blending with poly (2,6‐dimethyl‐1,4‐diphenylene oxide) (PPO). In particular, to render the beta form in these blends, starting with samples containing the α or γ froms, requires much lower temperatu…
Abstract The synthesis and living cationic polymerization of 11‐[(4‐cyano‐4′‐biphenyl)oxy]‐undecanyl vinyl ether ( 6 – 11 ) are described. The mesomorphic phase behavior of poly( 6 – 11 ) with different degrees of polymerization was compared to that of 6 – 11 and of 11‐[(4‐cyano‐4′‐biphenyl) oxy] undecanyl ethyl ether…
We present calculations of the local frequency spectrum of 〈110〉-split-interstitial atoms in bcc metals with the use of the Green's-function method. The dumbbell vibrates with low-frequency resonant modes and high-frequency localized modes with little contribution from the host frequencies. In agreement with experimen…
A useful magnitude of angular selective transmittance of incident unpolarized light is demonstrated in obliquely deposited aluminum. Required deposition procedures and anisotropic optical properties are discussed. Angular selectivity is very strong at visible wavelengths but both experiment and theory indicate that a…
Abstract A series of novel dialdehydes as new monomers, 4,4′‐diformyl‐α,ω‐diphencarbonylalkane, 4,4′‐diformyl‐3,3′‐methoxy‐α,ω‐diphencarbonylalkane, and 4,4′‐diformyl‐3,3′‐ethoxy‐α,ω‐diphencarbonylalkane, was prepared from aliphatic diacid chloride with p ‐hydroxybenzaldehyde, vanillin, and 3‐ethoxy‐4‐hydroxybenzaldeh…
The kinetics of decomposition of formic acid on Ru(001) have been investigated with thermal desorption mass spectrometry following the adsorption of DCOOH and HCOOH at both 130 and 305 K. Formic acid chemisorbs dissociatively on the perfect (001) surface via O–H bond cleavage to form a formate and a hydrogen adatom, a…
Abstract The overall crystallization and crystal melting of one low‐molecular mass poly(ethylene oxide) (PEO) fraction (MW 3000) have been investigated by differential scanning calorimetry (DSC) and in situ small‐angle x‐ray scattering (SAXS). The salient new results indicate that initial transient crystals with nonin…
It is known that polyalkylthiophenes show reversible thermochromism within a well-defined temperature range. The vibrational infrared and Raman spectra are used as structural probes for understanding the structures of polyhexyl and polyoctyl thiophenes at room temperature and their evolution with temperature during th…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNear-Infrared Fluorogenic Labels: New Approach to an Old ProblemGabor Patonay and Miquel D. AntoineCite this: Anal. Chem. 1991, 63, 6, 321A–327APublication Date (Print):March 15, 1991Publication History Published online30 May 2012Published inissue 15 March 1991https://pubs.a…
Abstract An investigation of the influence of crystalline microstructure on fatigue crack propagation (FCP) in high‐density polyethylene (HDPE) is reported. Various thermal histories were used to generate samples with the same crystallinity and supermolecular structure for three different molecular weight HDPEs. Estim…