Materials Literature
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Raman scattering from one- and two-magnon excitations in various rare-earth orthoferrites are studied. The magnetic in-plane and out-of-plane anisotropy energies of these systems are obtained and discussed based on the two-sublattice model of ironspins. Detailed temperature dependence of the frequencies of two \(k{\co…
Dielectric relaxations in undiluted cis-polyisoprene (cis-PI) with narrow molecular-weight distribution were investigated. The normal mode process due to fluctuation of the end-to-end distance and the segmental mode process due to the local segmental motions were observed. The average relaxation time τn for the normal…
A recent measurement of the force-height relation for two layers of end-grafted polystyrene chains in toluene is shown to be in excellent quantitative agreement with our recent theory, which is an exact solution of self-consistent field equations applicable in the limit of strongly stretched chains. Two undetermined p…
The effects of ArF excimer laser irradiation on dehydrated high-purity silica glass were investigated on both the optical-absorption bands due to oxygen-deficient centers (ODC) and the formation of ${E}^{\ensuremath{'}}$ centers. With an intense uv flux from an excimer laser, an ${E}^{\ensuremath{'}}$-center density o…
An experimental and theoretical study of the lattice dynamics of MP${X}_{3}$ layered compounds (M=Mn,Fe,Ni,Zn; X=S,Se) has been carried out. We present room-temperature infrared and Raman spectra and the phonon dispersion curves calculated in the framework of an axially symmetric force-constant model. The parameters o…
The photodetachment cross section of the lithium anion is studied in the coupled cluster polarisation propagator approximation (CCPPA). The discrete pseudospectra are analysed by moment theoretical methods. The all-electron CCPPA cross section of this work differs considerably from older calculations that involve pseu…
The rectified Barkhausen noise envelope, induction rate dB/dt signal, and hysteresis curve have been measured simultaneously for an annealed and plastically deformed mild steel specimen. The two peaks in the Barkhausen noise envelope of the annealed specimen occurring in the knee regions of the hysteresis curve are du…
The gene for leucine dehydrogenase (EC 1.4.1.9) from Bacillus stearothermophilus was cloned and expressed in Escherichia coli. The selection for the cloned gene was based upon activity staining of the replica printed E. coli cells. A transformant showing high leucine dehydrogenase activity was found to carry an about…
The Wright etch [M. W. Jenkins, J. Electrochem. Soc. 124, 757 (1977)], hitherto used to reveal defects in silicon, has been examined as a defect etchant for GaAs epitaxial layers on silicon. Various calibration techniques, including transmission electron microscopy of etched epitaxial layers, have been used to establi…
A unified model of the low-frequency dielectric response in KNbO 3 is proposed to reconcile all the infrared, Raman, hyper-Raman and dielectric results obtained in all phases. This model, based on the coexistence of a soft phonon and a relaxation mode, is applied to fit new Raman scattering results and to analyse alte…
In this paper we examine the dielectric and structural properties of hard polarizable multipolar models for liquid water. The theoretical results were obtained by solving the self-consistent mean field (SCMF) approximation together with the reference hypernetted-chain (RHNC) theory. The dielectric constants are in goo…
A new experimental approach for determining photoionization matrix elements which avoids the spin analysis of the photoelectron is presented for the case of 2p photoionization of atomic magnesium by 80-eV photons. Our experimental results clearly demonstrate the inadequacy of presently available theoretical calculatio…
It is shown via state-of-the-art theoretical calculations that self-diffusion in diamond is dominated by vacancies, independent of the position of the Fermi level. This is very different from self-diffusion in silicon and germanium, where vacancies, interstitials, and direct-exchange mechanisms all have comparable act…
Extensive first-principles calculations are presented for the formation energies and migration barriers of elementary defects in graphite, as well as for the activation energy of atomic exchange. The calculations show that the long-held view, that atomic diffusion in graphite occurs via the direct-exchange mechanism,…
D-galactose-binding (or chemoreceptor) protein of Escherichia coli serves as an initial component for both chemotaxis towards galactose and glucose and high-affinity active transport of the two sugars. Well-refined x-ray structures of the liganded forms of the wild-type and a mutant protein isolated from a strain defe…
A diluted classical spin chain with competing exchange interactions is studied by the transfer matrix method. It is found that a nonmagnetic impurity perturbs the helical spin structure and leads to a new local equilibrium spin complex. Numerical results for the correlation functions are discussed in connection with t…
Neutron diffraction studies on Fe0.8M0.2Sn (M : Mn, Co) over a temperature range 400 K to 20 K show spin reorientation features in the Mn substituted compounds, while in the Co substituted one the spins are locked along the c direction even down to 20 K.
Porphyrins are known to be accumulated and retained by tumours and atherosclerotic plaques. This property has been used for a new therapeutic approach called photodynamic therapy. In this study we assessed whether the presence of arterial hypertension could modify porphyrin turnover in the vascular wall. At various ti…
Specific heat and Raman scattering were measured on sintered samples with x around 0.5, which show a sharp metal-to-insulator transition (MIT) with increasing temperature. Specific heat below MIT can be well expressed by C = γT + βT3 + δT3 ln T with parameters comparable to those of TiBe2. Spectrum of Raman scattering…
Presents experimental results on the electrode-fall of local discharge on electrolytic surfaces, which simulate the surfaces of wet polluted insulators. A rod-plane electrode system with the electrolyte layer on the plane electrode was used. This electrode system was set in a Pyrex glass chamber. The air pressure in t…