Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
Formation of grain oriented Nd-Fe-B magnets from melt-spun ribbons by hot deformation has been studied using electron microscopy. It is shown that deformation and alignment of Nd2Fe14B magnets result from a combination of plastic deformation, grain boundary migration, and grain boundary sliding. Due to a limited numbe…
Measurements of the effect of uniaxial stress on the frequency of the k≊0 optical phonons in heat-treated benzene-derived graphite fibers have been performed using first-order Raman scattering. Application of uniaxial stress along the fiber axis is found to cause polarization-dependent splittings and shifts of the Ram…
The validity of nucleation and domain wall pinning models has been examined in R-Fe-B magnets by correlating the hard magnetic properties with the microstructure and magnetic domain structure. The nucleation model can be used to explain the magnetic properties of R-Fe-B magnets at low temperatures, but it fails at hig…
A long standing problem in numerical statistical mechanics has been the incorporation of the long range, many-body hydrodynamic forces between particles in suspension. In this paper I describe a general computational method for calculating the forces and torques exerted by slowly moving spheres suspended in an incompr…
This paper describes a type of vibrating-sample magnetometer capable of sensitivity exceeding 10−8 emu. The instrument is 1000 times more sensitive than a conventional VSM with comparable working space, and is much quicker to use than a SQUID magnetometer, which generates point-by-point data. The magnetic sample is mo…
The structures and the magnetic properties of some novel ternary compounds were studied. These compounds have the approximate composition RFe10T2, where T represents Cr, V, Ti, Mo, W, or Si. The structure of all these compounds can be derived from the tetragonal ThMn12 structure type, but the crystallographic position…
Density-functional calculations using the full-potential linearized augmented-plane-wave (FLAPW) film method have been used to compute the effective potential for electrons at different surfaces of Al, Ni, Cu, Ag, and W. In each case, the average of the potential parallel to the surface is reproduced well by a simple…
The dynamics of an electron in a one-dimensional tight-binding model with incommensurate sinusoidal modulation (Harper's model) is studied numerically. The width of a wavepacket of an electron put on a single site at the time t =0 exhibits such asymptotic time evolution as \(\sqrt{\langle\varDelta x^{2}\rangle}\sim t^…
Large ‘‘jumps’’ in the magnetostriction have been observed in twinned single crystals of Tb0.3Dy0.7Fe1.9 (Terfenol-D) for magnetic fields parallel to the crystalline [112̄] direction. The interpretation of these large magnetostriction discontinuities is based upon a model of twinned dendritic Terfenol-D in which the m…
The magnetic structure of small CoFe2O4 particles has been investigated as a function of the particle size. Samples (in the 10–100 nm size range and up) were prepared by chemical precipitation followed by a heat treatment at relatively low temperatures. Mössbauer spectra of the 57Fe nuclei, obtained with a longitudina…
Diffraction by two-dimensional surface-relief dielectric gratings are analyzed using rigorous three-dimensional vector coupled-wave approach. The method applies to arbitrary plane wave angle of incidence, wavelength, and polarization. In the resulting conical diffraction, the input TE and TM polarization are coupled a…
13 C‐NMR spectra of whole native cells of Methylobacterium AM1 show dominant signals belonging to poly(β‐hydroxybutyrate) and trehalose. Fractionation of the cells demonstrates that the poly(β‐hydroxybutyrate) is located in the storage granules and that the trehalose is located in the cytosol. The observation of relat…
The phason dispersion relation has been measured in the smectic-${\mathrm{C}}^{\mathrm{*}}$ phase of the ferroelectric liquid crystal p-decyloxybenzylidene-p'-omino-2-methylbutyl cinnamate (DOBAMBC) together with the temperature dependence of the phason and amplitudon excitations, by optical mixing spectroscopy. The o…
Fully state-resolved analysis of NO molecules desorbed from an oxygen-covered Ni(100) surface by uv radiation (\ensuremath{\lambda}=193 nm) yields the operation of two desorption channels, thermal and nonthermal, via electronic excitation. The latter fraction exhibits as a particular feature pronounced spin-orbit sele…
The radiation-enhanced diffusion of implanted Au markers in amorphous Si has been measured in the temperature range 77–693 K. Samples were irradiated with 2.5 MeV Ar ions. The diffusion coefficients show three well-defined regions. For temperatures <400 K, diffusion is athermal and due to ballistic mixing. For…
A factorization ansatz for the triplet direction correlation function c (3) is combined with the exact relation between c (3) and the derivative of the pair function c (2) with respect to density to derive a simple and tractable approximation for c (3) in dense, classical fluids. The predictions of this approximation…
N3-(4-Methoxyfumaroyl)-L-2,3-diaminopropionic acid (FMDP; 1, R = OMe), a member of a new class of glutamine analogues, has been investigated as an inhibitor of pure Escherichia coli glucosamine synthetase. Product and dead-end inhibition studies indicate an ordered association to the enzyme with the sugar molecule bin…
We report a variety of measurements on fluid interface motion through model porous media. The dynamics shares many features with other systems pinned by random fields. Over a range of pressures randomness pins the interface. In this range there are many metastable interface configurations and relaxation is extremely s…
We study the low-temperature properties of glasses in a model consisting of elastic dipoles placed randomly in an elastic continuum. We use Monte Carlo annealing to find glassy minimum-energy states and then determine the density of states for small angular oscillations of the dipoles. The coupling of these modes to t…
A review of ceramic matrix composites is presented as related to their type, use, and fabrication. Ceramic composites have the potential for high fracture toughness, resistance to catastrophic failure, high strength, low density, low thermal expansion, and high temperature capability and oxidation resistance. For cont…