Materials Literature
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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…
Compounds of the form RCo4-xFexB are ferromagnetic for R = Pr, Nd, Sm (x < 2) and ferrimagnetic for R = Er, Tm, Lu, with Tc ∼ 500 - 600 K. 57Fe Mössbauer spectra yield their magnetization directions, which depend both on the R.E. anisotropy and on the transition metal anisotropy.
The electrical resistivity and magnetic susceptibility of amorphous ${\mathrm{Cr}}_{\mathrm{x}}$${\mathrm{Ge}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$ alloys (0\ensuremath{\le}x\ensuremath{\le}0.65) prepared by means of the flash-evaporation method were investigated in relation to the amorphous structure. The partial pa…
A number of NH4HSeO4-NH4HSO4 mixed crystals have been grown. The system exhibits limited solubility in the solid state. The limiting solid solutions correspond to x = 0.32 and 0.67 (x - molar fraction of NH4HSO4). Based on X-ray diffraction, Differential Thermal Analysis and dielectric studies, the phase diagram has b…
Abstract The present paper is concerned with a crystallization process which occurs in the interior of a polymer melt, when its boundary (mold wall etc.) is suddenly quenched. As polymer melts are prone to supercooling, dispersed nucleation can take place at a distance from the boundary, if the local temperature has b…
Magnetic characteristics of NdCo2Si2 have been studied by magnetic and neutron diffraction measurements using a single crystal. Three antiferromagnetic phases were found below 32 K. A simple collinear antiferromagnetic phase is stable in the range 0-15 K where a metamagnetic process is observed. Square-wave structures…
The kinetics of thermal decomposition of aluminum sulfate was studied by dynamic and isothermal thermogravimetry. The nature of the solid phases was further examined by powder x-ray diffraction. Various kinetic models such as nucleation, phase boundary movement, diffusion and the homogeneous reaction were tested. Effe…
Abstract The crystallization behavior of polyetheretherketone (PEEK) was investigated by differential scanning calorimetry (DSC). The glass transition temperature of PEEK shifts to higher temperatures with an increase in crystallinity. Heat‐treated PEEK showed double peaks in their DSC curves, which is a characteristi…