Materials Literature
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Ring-opening polymerization of 1,5-dioxepan-2-one initiated by 1,1,6,6-tetra-n-butyl-1,6-distanna-2,5,7,10-tetraoxacyclodecane was carried out in chloroform, dichloromethane, or 1,2-dichloroethane. Effects of reaction temperature, solvent, and monomer-to-initiator ratio were investigated. Polymerization kinetics showe…
We investigated temperature-dependent optical conductivity spectra of a ${\mathrm{Nd}}_{0.7}{\mathrm{Sr}}_{0.3}{\mathrm{MnO}}_{3}$ single crystal. We found that polishing and surface scattering effects on the ${\mathrm{Nd}}_{0.7}{\mathrm{Sr}}_{0.3}{\mathrm{MnO}}_{3}$ crystal surfaces could significantly distort the op…
47,49 Ti, 89 Y and 139 La NMR measurements have been performed to study local magnetic properties of the Mott-Hubbard insulators YTiO 3 and LaTiO 3 . In particular, the magnetic structure of the ferromagnetic (antiferromagnetic) state of YTiO 3 (LaTiO 3 ) is discussed based on the analysis of 47,49 Ti frequency-swept…
A large magnetoresistance appearing below the ${T}_{c2}\ensuremath{-}\mathrm{CDW}$ (charge-density wave) transition temperature in ${\mathrm{NbSe}}_{3}$ has been studied under various pressures including pressure above the critical pressure where the ${T}_{c2}\ensuremath{-}\mathrm{CDW}$ phase is suppressed totally. Th…
In the present article, the effects of Al, Zn, Fe, Ni, and Cu powders on the thermal degradation of waste polystyrene were studied. The results show that the catalytic effects of metal powders have a relationship with their activities. The catalytic effects increase with the increasing activities of metals. It is sugg…
We present a model describing the Urbach tail of exciton absorption spectra in ferroelectric materials with order-disorder-type phase transition. In addition to the thermal effect of exciton-lattice interactions, the internal Stark effect by the local electric field due to the displacement of protons is taken into acc…
A high-resolution magnetic circular dichroism (MCDA) study of the sharp 1.404-eV zero-phonon absorption line associated with interstitial nickel in high-pressure synthetic diamond is reported. A model is presented attributing the absorption to internal transitions within the ${3d}^{9}$ configuration of ${\mathrm{Ni}}_…
Director tilting of liquid crystal (LC) molecules on photosensitive alignment layers has been investigated. The layers, polyimides with photoisomerizable groups in their main chains, were irradiated with unpolarized near-UV (UPUV) light at oblique incidence. The irradiated film was found to align LC molecules homogene…
Polymer films are serving as passive regions in fast logic circuits and as active regions in organic optoelectronic devices, such as light-emitting diodes. Recent data illustrated the strong anisotropy in the thermal conductivity of polyimide films of thickness near 1 μm, with the in-plane value larger by a factor of…
The phase behavior of intermediately segregated (χN = 45) poly(ethylene)-poly(ethylethylene) (PE–PEE) diblock copolymers and PE–PEE binary blends are characterized using transmission electron microscopy and small-angle X-ray scattering. Surprisingly, the preparation-dependent, nonequilibrium phase behavior can be over…
Temperature dependence of reflectivity and transmission infrared spectra and photoinduced activity of $R{\mathrm{NiO}}_{3}$ $(R=\mathrm{Sm},$ Pr) were studied in order to elucidate the mechanism responsible for the metal-insulator transition at ${T}_{\mathrm{MI}}\ensuremath{\approx}135\mathrm{K}$ and \ensuremath{\appr…
It has been generally accepted that the threshold structure observed in the oxygen K-edge x-ray absorption spectrum in $3d$-transition-metal oxides represents the electronic structure of the $3d$ transition metal. There is, however, no consensus about the correct description. We present an interpretation which include…
The crystallization of Ba-ferrite/sapphire(001) films of various thicknesses has been studied using synchrotron x-ray scattering, field emission scanning electron microscope, and atomic force microscope. In films thinner than 1000 Å, Ba-ferrite amorphous precursor was crystallized into perpendicular grains keeping the…
Binding energies of the N 1s level in hard and elastic CNx films are investigated by means of theoretical studies of model molecules. Results for the model systems are obtained from ab initio Hartree–Fock calculations, where the core electron binding energies are determined using the delta self-consistent-field method…
We report calculations, using electron uncorrelated and correlated wave functions, of the electronic and vibrational properties which pertain to certain nonlinear optical properties for HF, HCl, and HBr. Our main focus is on vibrational effects (zero-point-vibrational averaging and pure vibration). Analysis of the res…
Visible electroluminescence (EL) has been observed from Ag (film or paste)/native SiO2/n-type Si structures. The diodes show good rectification behavior and the EL occurs only under reverse bias conditions when the top Ag electrode is negative. For p-type samples, a forward bias is required. The intensity of the EL is…
The structure of two metal phthalocyanines, MPc where M=Sn and Mg, have been determined by gas-phase electron diffraction for the first time; furthermore, the structure of ZnPc established earlier by the same technique has been reanalyzed. The focus of these studies is the position of the metal ion relative to the 16-…
In this study the instrumented tensile (ITI) and falling weight impact (IFWI) behavior of injection-molded α- and β-phase polypropylene (PP) homopolymers were compared at ambient temperature in a broad melt flow index (MFI = 0.7–13 dg/min) range. It was found that the toughness of β-PP is superior to the α-PP: the dif…
The water sorption characteristics of poly(ethylene terephthalate) (PET) amorphous samples of 250 μm thickness have been studied at various temperatures in a saturated atmosphere. Concerning diffusivity, one can distinguish the following two domains characterized by distinct values of the activation energy: ED ≈ 36 kJ…
We perform ab initio pseudopotential calculations for a nanocontact between a metallic carbon nanotube and a copper chain. We find that the on-top position is the most stable geometry of the copper chain on the nanotube and a local energy gap of $\ensuremath{\lesssim}0.1 \mathrm{eV}$ opens as the mirror symmetry of th…