Materials Literature
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We present a theoretical result on the ordering of cylindrical morphology in diblock and triblock copolymers. The equilibrium morphology of A–B diblock and A–B–A triblock copolymer films is shown to have the cylinders oriented parallel or vertical to the surface, depending on the film thickness and surface tensions. A…
We present a model that describes grain-boundary-limited conduction in polycrystalline semiconductors, for thermally assisted ballistic as well as diffusive transport, both for degenerate and nondegenerate doping. In addition to bulk parameters (the carrier effective mass and mean free path) the model contains grain b…
The phase separation of ultrathin polymer blend films of deuterated poly(styrene)/poly(vinylmethylether) leads to a variety of film morphologies, depending on polymer composition. Phase-separation measurements are made at a constant temperature difference from the critical temperature, leading to a bicontinuous spinod…
The synthesis of the MCM-41 materials with novel hollow tubular morphology in high alkaline condition was studied in detail. The tubular structure can be obtained in a narrow range of water/C 16 TMAB molar ratio, in which lamellar membranes consisting of the hexagonal arrangement of rod micelles exist. Tubular structu…
We find a striking peak structure in the magnetoresistance of the quasi-two-dimensional conductors $\ensuremath{\beta}\ensuremath{-}{(\mathrm{B}\mathrm{E}\mathrm{D}\mathrm{T}\ensuremath{-}\mathrm{T}\mathrm{T}\mathrm{F})}_{2}{\mathrm{I}}_{3}$ and $\ensuremath{\alpha}\ensuremath{-}{(\mathrm{B}\mathrm{E}\mathrm{D}\mathrm…
Electronic structures of ten kinds of rare-earth sesquioxide single crystals ( R 2 O 3 ; R =La, Pr, Nd, Sm, Eu, Gd, Er, Tm, Yb and Lu) were investigated by 4 d -4 f resonant photoemission measurement. The information of the electronic structure, especially the relative binding energy of 4 f state and O 2 p valence ban…
A method is described for measuring the heat and rate of recrystallization following partial melting. The method uses a specific sequence of temperatures with a differential scanning calorimeter, and the melting and recrystallization processes were confirmed by optical observations. The method was applied to poly(buty…
The in situ formation of a compatibilizer, consisting of a copolymer of PA grafted onto a maleic anhydride (MA) containing polymer, is essential for the morphology and properties of the corresponding PA blends. In this study four blends, containing PA-6 or PA-6.6 and EPDM-g-MA or poly(styrene-co-maleic anhydride) (SMA…
We report the structure and magnetic studies of carbon coated nanocrystals of nickel and cobalt synthesized in a special low carbon to metal ratio arc chamber. Powder x-ray diffraction profiles show peaks associated with single phase of fcc nickel or cobalt and major peaks of graphite with no evidence of carbides or s…
We use the local spin-density approximation in density-functional theory to study the electronic structure of ${\mathrm{TiO}}_{2}$ and its (110) stoichiometric surface, as well as ${\mathrm{Ti}}_{2}{\mathrm{O}}_{3}$ and the reduced (110) surface, which are examples of reduced ${\mathrm{TiO}}_{2},$ in order to address…
In order to interpret the phonon-assisted optical transitions in semiconductor quantum dots, a theory is developed comprising the exciton interaction with both adiabatic and Jahn-Teller phonons and also the external nonadiabaticity (pseudo-Jahn-Teller effect). The effects of nonadiabaticity of the exciton-phonon syste…
High-resolution electron microscopy of amorphous interlayers (a-interlayer) formed by solid-state diffusion between metal thin films and silicon is reviewed. In this paper, an overview of the development is presented. Pertinent data obtained on the growth kinetics and structure of a-interlayers in polycrystalline meta…
Electronic structures of electron-doped ${\mathrm{SrTiO}}_{3\ensuremath{-}\ensuremath{\delta}}$ and ${\mathrm{Sr}}_{1\ensuremath{-}x}{\mathrm{La}}_{x}{\mathrm{TiO}}_{3}$ have been investigated within the ab initio band-structure approach using a supercell containing eight basic units. A small amount of electron doping…
Hydrolysis of poly(L-lactide) (PLLA) films in 0.01N NaOH at 37°C was investigated by gel permeation chromatography, differential scanning calorimetry, scanning electron microscopy, and polarizing optical microscopy. The change in molecular weight distribution and surface morphology of PLLA films during hydrolysis reve…
The electronic structure of nitrogen-containing diamondlike films prepared by sputtering was determined by photoelectron spectroscopy. The $\mathrm{N}1s$ core-level spectra are constituted by two peaks at 400.5 and 398.2 eV associated with substitutional $\mathrm{N}{\mathrm{sp}}^{2}$ in aromatic rings and N bonded to…
The first and second hyperpolarizabilities (β and γ) of eight molecules at a fundamental wavelength of 1064 were measured by gas-phase electric-field-induced second-harmonic generation (EFISH), gas-phase hyper-Rayleigh scattering (HRS), and liquid-phase HRS experiments. The EFISH measurements give accurate values of β…
The electrical conductivity of a composite model system formed by highly structured carbon black (CB) filled, within an amorphous polymer, poly(ethylene terephtalate) composite is studied. The dc conductivity as a function of CB content follows a scaling law of the type $\ensuremath{\sigma}\ensuremath{\propto}(p\ensur…
A new class of self-assembling transmembrane ion channels based on cyclic β 3 -peptides is described. Cyclic peptide subunits were designed to adopt flat, ring shaped conformations and stack through extensive backbone-backbone hydrogen bonding to form tubular channel structures. Candidate channel-forming peptides cycl…
We point out a remarkable similarity between the resistivity behavior observed recently in single-wall carbon nanotubes and that of highly conducting polymers, in particular the change in sign of the resistivity temperature dependence from metallic to nonmetallic as the temperature is lowered. In analogy to the conduc…
We report experiments on gold clusters in the size range 2--4 nm, embedded in an alumina matrix. The metallic particles are produced with a laser vaporization source and codeposited with a dielectric vapor as a thin film on a substrate. Our technique allows varying the cluster size at a given metal concentration. Thes…