Materials Literature
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Gas barrier properties of alkylsulfonylmethyl-substituted poly(oxyalkylene)s are discussed. Oxygen permeability coefficients of three methylsulfonylmethyl-substituted poly(oxyalkylene)s, poly[oxy(methylsulfonylmethyl)ethylene] (MSE), poly[oxy(methylsulfonylmethyl)ethylene-co-oxyethylene] (MSEE), and poly[oxy-2,2-bis (…
The phase and orientational behaviors of a series of liquid crystalline (LC) AB-type diblock copolymers comprising thermotropic main-chain (MC) polyester and side-group (SG) polymethacrylate blocks were investigated by X-ray diffraction. The MC and SG blocks were phase separated and gave rise to their individual mesop…
Synthesis of nanocomposite two-phase permanent magnet materials by mechanical milling requires optimization of the volume fractions of the two phases, milling time, heat treatment temperature, and time. In the present study, optimization of milling time, heat treatment temperature, and time have been carried out by fi…
Ultraviolet-photoemission spectroscopy has been employed to investigate the valence-band electronic structures of the magnetic alloys ${\mathrm{Co}}_{2}\mathrm{MnSn},$ ${\mathrm{Cu}}_{2}\mathrm{MnAl},$ and ${\mathrm{Pd}}_{2}\mathrm{MnSn}.$The valence band of ${\mathrm{Co}}_{2}\mathrm{MnSn}$ extends to approximately 5…
The recent results for the contact value of the radial distribution function obtained from large-scale molecular dynamics and Monte Carlo simulations of systems of dense hard spheres [M. D. Rintoul and S. Torquato, J. Chem. Phys. 105, 9258 (1996)] are compared to those of the Padé equation of state for a hard-sphere f…
The enthalpy relaxation of a series of linear amorphous polyesters (poly(propylene isophthalate) (PPIP), poly(propylene terephthalate) (PPTP), poly(ethylene terephthalate) (PETP), and poly(dipropylene terephthalate) (PDPT)) has been investigated by differential scanning calorimetry (DSC). These polyesters have been an…
A series of viologen polymers based on 4,4‘-bipyridyl and the ditosylates of trans- 1,4-cyclohexanedimethanol and 1,8-octanediol was prepared by the quaternization reaction in acetonitrile. Their polyelectrolyte behavior in a common organic solvent was studied by viscosity measurements, and their chemical structures w…
We have calculated a set of crystal-field parameters, Bnm, for Dy3+ through Yb3+ ions in M (II) sites in the crystal Sr5(PO4)3F (SFAP). The Bnm parameters were derived from lattice-sum calculations and from analyses of the optical spectra reported for Ho3+, Er3+, and Tm3+ individually doped into SFAP. These parameters…
Green's-function methods are frequently used in the calculation of both the extended and the near-edge structures observed in x-ray-absorption and electron-energy-loss spectroscopies. To date, calculations based upon these methods have tended to be based upon a superposition of atomic potentials used to represent the…
Water absorption in thin films (<1000 Å) of a commercial polyimide was evaluated by monitoring dimensional changes induced by a humid environment. Film thickness was measured using x-ray reflectivity, which is a nondestructive technique offering angstrom resolution in the measurements of thin film or multilayer thickn…
Fluid metals are typical examples of materials whose electronic structures depend strongly on the thermodynamic state of the system. The most striking manifestation of this state dependence is the metal–non–metal transition which occurs when the dense liquid evaporates to the dilute vapour or when the fluid is expande…
The use of polymer-dispersed liquid crystal films to fabricate gratings was demonstrated. The written gratings are permanent, but are electrically switchable. In this article, we report the results obtained from the dynamical studies of gratings formed in polymer-dispersed liquid crystal films having various liquid cr…
The affect of annealing polycrystalline chemical vapor deposition (CVD) diamond in vacuo up to 1900 K has been studied using electron paramagnetic resonance (EPR) and infrared absorption. The concentration of the EPR centers at $g=2.0028$ and the infrared absorption in the CH region are insensitive to annealing below…
The effects of isotopic substitution on the $\ensuremath{\Gamma}$-point phonon in isotopically enriched ${(}^{70}\mathrm{Ge}$, ${}^{73}\mathrm{Ge}$, ${}^{74}\mathrm{Ge}$, and ${}^{76}\mathrm{Ge}$) and disordered (natural Ge and ${}^{70/76}\mathrm{Ge}$) germanium samples have been measured with Raman spectroscopy. We b…
The first-order Raman frequency shifts of the A g (2) + B g (2) mode in a CaWO 4 crystal were measured in the temperature range of 77∼771 K. The frequency shift for this mode changes very slowly with increasing temperature. The temperature dependence of the frequency shift of the A g (2) + B g (2) mode was analyzed us…
The title compound, lanthanum aluminium borate, has been found to be isostructural with hexagonal NdAl2.07(B4O10)O0.6. Each La ion is coordinated by six O-atoms to form a trigonal prism, while each Al is coordinated by five O-atoms to form a pyramid.
Polymer solutions do not wet the substrate, even when the solvent is wetting. It is suggested here that it becomes difficult to squeeze polymer molecules into thin films found near the contact line due to adverse changes in the polymer entropy. Models are used to show that as the film thins a potential barrier is enco…
One-pot oxidation polymerization of dithiols, obtained from bifunctional five-membered cyclic dithiocarbonates (4a and 4b) with two equivalents of amines, was studied. The monomers 4a and 4b were synthesized by the reactions of bisphenol A diglycidyl ether and neopentyl glycol diglycidyl ether with carbon disulfide, r…
The electronic structures have been calculated using the INDO/S-CI method, and following combination with the sum-over-sates method the dynamic second-order polarizabilities have been computed for the ${\mathrm{Ba}}_{3}{(\mathrm{B}}_{3}{\mathrm{O}}_{6}{)}_{2}$ microspecies of $\ensuremath{\beta}\ensuremath{-}{\mathrm{…
The nanocrystalline hard magnetic Nd2Fe14B phase plays a crucial role in the development of exchange spring magnets. We report the hardening mechanism of nanocrystalline Nd2Fe14B, as well as the effect of small amounts of magnetic additions on the hardening behavior. It is shown that the hardening mechanism is of the…