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。
We determine bandwidths and critical-point positions with respect to the valence-band edge for the valence bands of several extensively studied semiconductors (with an accuracy of about 0.3 eV) by using photoemission densities of states derived from photoemission spectra obtained in the 24-78-eV photon energy range. T…
Electronic transport has been investigated in ${\mathrm{As}}_{2}$(${\mathrm{Se}}_{1/3}$ ${\mathrm{Te}}_{2/3}$${)}_{3}$ and Ge(${\mathrm{Se}}_{1/3}$${\mathrm{Te}}_{2/3}$ ${)}_{2}$ amorphous semiconductors through measurements of photoconductivity, optical absorption, dark conductivity, thermoelectric power, and field e…
Mutant adenylosuccinate lyases of Bacillus subtilis were prepared by site-directed mutagenesis with replacements for His141, previously identified by affinity labeling as being in the active site [Lee, T. T., Worby, C., Dixon, J. E., and Colman, R. F. (1997) J. Biol. Chem. 272, 458-465]. Four substitutions (A, L, E, Q…
The spectra of corona discharges in air at atmospheric pressure, in a 0·6 m point-plane gap under positive impulse voltage, have been measured in the near-ultraviolet and visible regions. Two types of corona discharges have been investigated: the first corona which develops from the electrode tip; and the leader coron…
A technique is presented which enables the recovery of the probability distribution for single scattering from plural-scattering electron energy loss data. Neither the scattering parameter t/λ nor details of the component processes need be known. The computational method uses Fourier series in order to overcome a numb…
Luminescence at 368 nm from crystals containing ${\mathrm{Eu}}^{2+}$ exhibits the small spectral shifts from host to host typical of a parity-forbidden rare-earth transition, and yet has the emission oscillator strength ($f\ensuremath{\gtrsim}1$) of a highly allowed transition. It is improbable that this anomaly can b…
In the layer structure MoS 2 , the oscillatory inter-band magneto-optic absorption has revealed a mass ratio of the order of 0.01. Theory is presented to show that this mass may be associated with the H-point of the Brillouin zone. Moreover, it is proposed that the origin of the mass is an instability of the equally-s…
Comparative powder Raman studies on zircon (ZrSiO 4 ) and hafnon (HfSiO 4 ) are reported. It is shown that rotational and translational modes of the same symmetry can be identified by comparing the spectra of these two crystals in a similar way as could be done by means of isotopic substitution. The authors also show…
We report a method for operating twisted nematic devices with rapid turnoff times by using a nematic material with variable dielectric anisotropy. These are useful as fast shutters and colour switches, and can be operated at a 25 Hz repetition rate.
Abstract The crosslink density of small microtomed samples of rubber vulcanizates has been determined using a gas‐chromatographic method for estimating the amount of solvent in the swollen rubber. The method may be used for determining the variation in crosslink density through thick rubber articles, for determining t…
Menachem Rahat, Richard D. Campbell, Three Forms of the Tentacled and Non-Tentacled Fresh-Water Coelenterate Polyp Genera Craspedacusta and Calpasoma, Transactions of the American Microscopical Society, Vol. 93, No. 2 (Apr., 1974), pp. 235-241
Through extensive testing in fission-reactor programs, molten Li2BeF4 is known to be compatible with graphite and with many useful structural metals. In service as a Controlled Thermonuclear Reactor blanket-coolant fluid, however, corrosion by this molten salt may be enhanced by (a) the effect of magnetically induced…
Effect of pressure on the CuAu alloy having a long period ordered structure has been studied using mainly a tetrahedral-anvil type press. The alloy was annealed at various temperatures ranging from 350°C to 500°C during application of pressure. After temperature and pressure were reduced to ambient ones, the structure…
Single crystals of Pb3GeO5 were grown from the melt by the Czochralski technique. Based on observations of the domain structure under mechanical stress, and the presence of an SHG signal, the crystals are ferroelastic and possibly ferroelectric, but show no phase transitions up to the melting point (738°C). The powder…
Thermal stabilities of mature insoluble collagen, salt-precipitated fibrils of acid-soluble collagen and acid-soluble collagen in solution were compared as a function of acid pH. Both insoluble and precipitated collagens showed large parallel destabilization with decrease in pH, whereas the intrinsic stability of indi…
Differential cross sections for the elastic scattering of $\ensuremath{\alpha}$ particles by $^{208}\mathrm{Pb}$ have been measured over the laboratory energy range 16.0 to 25.5 MeV in 0.5-MeV steps and over the laboratory angle range of 30 to 170\ifmmode^\circ\else\textdegree\fi{} in 5\ifmmode^\circ\else\textdegree\f…
This paper outlines the development of a general macroscopic failure theory. The result is a relatively simple cubic equation where interaction coefficients for tension-tension and compression-compression strengths may be defined separately. Approximations for biaxial and triaxial normal stress interactions are includ…
The yarn torque developed by the applied tension in the torsion-balance apparatus described in Part 1 of this series is calculated by using an expression derived in an earlier paper. Differences in shape of net-torque–twist curves are studied for nylon monofilaments and model plied yarns; these differences in shape ar…
The transmission of monochromatic light through the sandwich cell of MBBA (a typical n -type liquid crystal) with vertical alignment is investigated. When the cell is set in crossed Nicol and controlled by a.c. voltages, the transmissivity is zero at any voltage V below the threshold value V th . When V > V th , it sh…
Abstract Poly(ethylene terephthalate) oxidizes on heating at 300°C in an air stream. Various literature has cited crosslinking under such conditions through a butanetriol or a biphenyltricarboxylic acid. In this study gelled polymer was found to contain the latter trifunctional compound, but not the former. In additio…