Materials Literature
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The microstructure of filtered cathodic vacuum arc deposited tetrahedral amorphous carbon films is studied as a function of ion energy. An optimum energy window in the density and C–C sp3 content at an ion energy of ∼90 eV observed in this study. It is shown that the density of the amorphous carbon films are closely r…
We use inelastic neutron scattering to measure the spin wave dispersion throughout the Brillouin zone of the double-exchange ferromagnet L${\mathrm{a}}_{0.7}$P${\mathrm{b}}_{0.3}$Mn${\mathrm{O}}_{3}$. Magnons with energies as high as 95 meV are directly observed and an unexpectedly simple Heisenberg Hamiltonian, with…
States of charge carriers in transition metal compounds with low-frequency zero-spin - nonzero-spin transitions (e.g. some Co compounds) are investigated. Such transitions indicate the appearance of magnetic excitons on the transition metal ions. Charge carriers interact strongly with the excitons via exchange forces.…
The localization of low-frequency vibrational modes in amorphous solids can be determined from incoherent neutron scattering. Time-of-flight data from polystyrene and polybutadiene show a localization of the boson peak modes to about ten monomers.
The Escherichia coli pdxC(serC) gene codes for a transaminase (EC 2.6.1.52). The gene is involved in both pyridoxine (vitamin B6) and serine biosynthesis and was overexpressed as a MalE/PdxC(SerC) fusion protein. The fusion protein was purified by affinity chromatography on an amylose resin and hydrolyzed in the prese…
A simple model is presented to describe the phase behavior in binary mixtures of a flexible polymer and a liquid crystal. By using the incompressible approximation to the Onsager theory which combined both the excluded volume interactions between the liquid crystals and the attractive interaction due to the alignment…
Nanocrystallite size distribution and structural properties in alternating hydrogenated nanocrystalline silicon/amorphous silicon multilayers were investigated by means of Raman scattering. The obtained Raman spectra show a broad peak at ∼480 cm−1 from amorphous Si and some small peaks superposed on the broad peak. Ac…
By dynamic light scattering we have studied concentrated suspensions of ``hard-sphere'' colloidal particles in their equilibrium and metastable fluid states. We have found a simple, as yet unexplained, scaling procedure which collapses the measured intermediate scattering functions describing structural relaxation and…
Near-edge x-ray absorption fine structure (NEXAFS) measurements were performed on a variety of carbon materials, covering a range of hybrid bonding character from pure sp3 type to pure sp2 type. Diamond, chemical vapor deposited (CVD) diamond films of varying quality. Diamond-like carbon (DLC) films, and graphite were…
The local atomic structure of ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3}$ ( $x\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.12,$ 0.21, and 0.25) has been studied using pair-distribution-function analysis of neutron powder-diffraction data. A change is seen in the local structure which…
The reliability of the continuous transformations of origin of the current density method, which makes the transverse paramagnetic current vanish (CTOCD-PZ), for the prediction of nearly gauge-origin independent molecular magnetic susceptibility and gauge-origin independent nuclear magnetic shielding, is proved on the…
For nematic liquid crystals, we study the local stability of a radial hedgehog against biaxial perturbations. Our analysis employs the Landau - de Gennes functional to describe the free energy stored in a ball, whose radius is a parameter of the model. We find that a radial hedgehog may be either unstable or metastabl…
一様気流中におかれた橋梁断面に作用する動的空気力は桁の状態量 (速度, 変位) で表すことが多い. そのために動的空気力係数は風速, 振動数の関数となり, 周波数領域の解析を強いられる欠点がある. 本研究では, 拡張変数を導入して定数系の微分方提式で空気力を表す有理関数近似法の橋梁断面への適用を検討している. (1) 最小二乗法と最小状態量法を適用し. 後者の方が拡張変数の数が少なくてすむこと, (2) 翼形断面の場合は, 拡張変数が1つ, 偏平箱桁では2つ, トラス断面では3つ程度導入すれば精度よく動的空気力を表現でき, フラッター限界風速も精度よく予測できることを明らかにしている.
We study various models of independent particles hopping between energy `traps' with a density of energy barriers , on a d-dimensional lattice or on a fully connected lattice. If decays exponentially, a true dynamical phase transition between a high-temperature `liquid' phase and a low-temperature `aging' phase occurs…
A random field Potts model is used to establish the spatial relationship between the nanoscale distribution of charged chemical defects and nanoscale polar domains for the perovskite-based relaxor materials lead magnesium niobate (PMN) and lead scandium tantalate (PST). The random fields are not set stochastically but…
The influence of the random field effects originating from charged chemical defects and nano-domain textures on the formation and dynamics of polar clusters is analyzed. The spatial distribution of the local fields is not totally random but contains some correlations in direction and strength. Polar clusters are class…
Molecular films of protein/polyion layers were assembled by means of alternate adsorption through electrostatic interaction. Glucose oxidase (GOD) and peroxidase (POD) were assembled in combination with sodium poly(styrenesulfonate) (PSS) and poly(ethyleneimine) (PEI), respectively. Enzyme activities of those films on…
The equilibrium shape of strained InAs quantum dots grown epitaxially on a GaAs(001) substrate is derived as a function of volume. InAs surface energies are calculated within density-functional theory, and a continuum approach is applied for the elastic relaxation energies.
Six-dimensional quantum dynamical calculations of the scattering of H_2 from a Pd(100) surface using a potential energy surface derived from density-functional theory calculations are presented. Due to the corrugation and anisotropy of the PES strong off-specular and rotationally inelastic diffraction is found. The de…
Ab initio molecular dynamics calculations of deuterium desorbing from Si(100) have been performed in order to monitor the energy redistribution among the hydrogen and silicon degrees of freedom during the desorption process. The calculations show that part of the potential energy at the transition state to desorption…