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。
ABSTRACT The erosion and cleaning effects of jets are enhanced when the degree of cavitation occurring on or near the bottom of the hole is increased. A new, STRuctured Acoustically Tuned Oscillating Jet ("STRATOJET") system causes the formation of large discrete vortex rings that promote cavitation to depths several…
Four UHV spectroscopies used for the compositional and chemical analysis of surfaces are discussed. These are X-ray Photoemission, Auger Spectroscopy, Secondary Ion Mass Spectroscopy, and Ion Scattering (both low and high energy). Descriptions of the basic processes and information contents are given, followed by a co…
Gd 3+ in glasses exhibit sharp g approximately=6.0 features in the EPR spectra. It is demonstrated that these features can be adequately accounted for by using the 'rhombic' spin Hamiltonian H=g c beta H.S+D(S z 2 -(S/3)(S+1))+E(S x 2 -S y 2 ) in the strong crystal field case. Computer simulations of the experimental…
Magnetic susceptibility, Mossbauer spectroscopy and powder neutron diffraction experiments have shown that iron(III) phosphate, FePO 4 , undergoes a novel spin reorientation transition at 17K between two antiferromagnetic phases. The ordered magnetic moments lie in the basal plane of the trigonal unit cell between the…
Transverse magnetoresistance is measured at magnetic fields up to 6.5 T at temperatures of 77K and 4.2K for highly oriented graphites; four samples of kish graphite with different crystallinity. The effect of the structural perfection of graphite on the field dependence of the exponent n in he magnetoresistance Delta…
The rate of oxidation of ammonia at atmospheric pressure on single wires and ribbons has been determined as a function of a gas flow rate and catalyst size. In agreement with boundary layer diffusion theory the function rx 1/2, where r is the average rate of reaction/unit area, and x is the length of the surface measu…
The rate of catalytic "NO" reduction by hydrogen and carbon monoxide over a char surface was measured and compared with the rate of noncatalytic "NO" reduction by char which has been previously reported to have a significant effect on "NO" emission control in a fluidized bed combustor of coal. In the presence of hydro…
X-ray diffraction peaks recorded from hematite derived from goethite by a dehydration reaction and its isostructural system corundum from diaspore exhibit systematic peak broadening for l ≠ 3n, which corresponds to the reflections belonging to either the obverse or reverse variant of hematite. The peak width of l = 3n…
Compositions GdF3Ce, Tb are efficient green phosphors under short-wavelength ultraviolet excitation. The Ce3+ → Tb3+ energy transfer occurs via the Gd3+ ions. Without Gd3+ ions the total transfer efficiency is considerably lower.
Optical data from single-crystal Mg[Pt${(\mathrm{CN})}_{4}$]\ifmmode\cdot\else\textperiodcentered\fi{}7${\mathrm{H}}_{2}$O together with calculations of the exciton energies allow us to draw conclusions on the existence of a self-trapped exciton, which becomes metastable by changing the relevant material parameters wi…
The crystal structure of the organic charge-transfer salt DBTTF–TCNQF4 is reported. The structure has been determined by single-crystal x-ray diffraction techniques and has been shown to consist of segregated stacks of donor and acceptor molecules. Within both the donor and acceptor stacks, significant dimerization is…
The low-frequency properties of a disordered one-dimensional diffusion model are determined. Of particular interest is the case where the distribution of hopping elements diverges for small values of the hopping elements. The density of states and the leading correction terms are calculated at low frequencies and the…
We describe a quantum Hamiltonian in one dimension with a quasiperiodic interaction, giving rise to a metal-insulator transition at high coupling. This model applies to a linear wave propagation in a modulated medium, naturally resulting in potentials with incommensurate periods, as is the case for organic linear cond…
Experimental results on Cu(001), Ni(001), and Ni(110) with the use of the newly developed technique of $k$-resolved inverse photoelectron spectroscopy (or angle-resolved ultraviolet bremsstrahlung isochromat spectroscopy) are presented and compared with the predictions of bulk band-structure theory. A theoretical mode…
A study is made of relaxation processes in polymer molecules which proceed via conformational transitions of the chain backbone from one rotational isomeric state to another. The conformational time-correlation functions are determined for several models of the process. Each model allows for the occurrence of both ind…
The rate of molecular reorientation in solid ${\mathrm{N}}_{2}$O and $\ensuremath{\alpha}$-CO is obtained from audio-frequency dielectric measurements. Both sets of data obey the Arrhenius expression. The rates extrapolate to mean reorientation times of one hour at temperatures well above the predicted dipolar orderin…
The mixing effects in the fused system LiCl–KCl are studied by molecular dynamics simulation. The predominant contribution of the Coulombic interaction is clearly detected, its nonlinear variation gives rise to the main part of the excess internal energy. This change reflects the structural ionic arrangement; at high…
The core-level binding-energy shifts for surface atoms relative to bulk atoms ("surface shifts") have been measured for the $2p$ levels of Na (220 meV) and Mg (140 meV) using synchrotron-radiation-excited photoelectron spectroscopy. For Al, both a surface shift and a broadening are considered. The sign and magnitude o…
A b initio LCAO SCF MO calculations were carried out on Fe-porphine, Fe-porphine-pyridine, and Fe-porphine-pyridine-carbonmonoxide which are typical intermediate-, high-, and low-spin complexes, respectively. Mössbauer spectra of ferrous porphyrins were analyzed theoretically by the evaluation of isomer shift (IS), qu…
Raman scattering and optical-absorption spectra in low-pressure, rf-sputtered $a$-Si are shown to exhibit a continuous variation with deposition temperature. A direct correspondence between changes in the inverse width of the TO-like phonon band and the optical gap is observed in sputtered and chemical-vapor-deposited…