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。
The work function of a single-crystal alumina covered with nanometer-size palladium clusters was measured using the Kelvin probe method. It increases rapidly with coverage and cluster size up to about 2 nm in diameter. The data indicate a formation of interface dipoles caused by charge transfer from ${\mathrm{Al}}_{2}…
Schottky-diode action in thiophene oligomer is investigated by current-density--voltage (J-V) and capacitance-voltage (C-V) measurements. An energy-band diagram is deduced that explains the diode characteristics for both unintentionally and highly doped thiophene oligomers. We conclude that the diode consists of a thi…
We observe a quadratic rise of the absorption coefficient with excitation energy in photoluminescence excitation spectra of porous silicon. Extrapolation to \ensuremath{\alpha}=0 yields an average band gap of microporous silicon about 0.2 eV above the luminescence line. Good agreement is obtained with an estimate of t…
On the basis of phenomenological theory, ferroelectric films with cells finite in three dimensions are studied by considering their practical applications in ferroelectric random-access memory. The lateral size dependence of the Curie temperature and the polarization is obtained and the stability of the ferroelectrici…
Grazing-incidence diffraction from superlattices has been described by a distorted-wave Born approximation. Using the example of a GaAs/AlAs superlattice, the influence of specular interface reflection on the diffraction pattern has been investigated experimentally and well explained by the theoretical treatment. A co…
We report here the magnetic and nonmagnetic electronic-structure calculations of the perovskite oxides LaM${\mathrm{O}}_{3}$ (M=Ti to Ni) and the orthorhombic ${\mathrm{LaScO}}_{3}$ performed using the tight-binding linear-muffin-tin-orbital method. Total-energy calculations for these systems reproduce the magnetic ph…
Advanced spatial light modulators both detect incident light and modulate reflected light. Each pixel may contain multiple photodetectors, a modulator, control circuitry, and signal-processing circuitry. Because each detector and modulator occupies only a fraction of the area of a pixel the optical efficiency of these…
Abstract SiC-SiC composites exhibit a non-brittle behaviour when the fibre-matrix bonding is controlled by the use of an interphase with a layered structure or microstructure, such as pyrocarbon, hex-BN or (SiC-PyC)n multilayers. The best mechanical properties are achieved when there is a balance between the crack def…
The antiferromagnetic state of the title compound has been investigated by the measurements of 1 H-NMR lineshape and nuclear spin-lattice relaxation rate, T 1 -1 , on a single crystal sample. Below the Nèel temperature, T N ∼ 6.7 K, the resonance line was observed to split into three pairs of peaks. The angular depend…
Abstract Perspectives are presented on the development of ceramics and ceramic matrix composites (CMCs) for high-temperature structural components. The emphasis is on design requirements and their role in directing research toward actual products. An important theme concerns the relative roles of fracture toughness an…
In this study a ferroelectric liquid crystal (FLC) monoacrylate (S)-4-(1-ethoxycarbonyl-1-ethyloxy)phenyl 4′-(11-acryloyloxyundecyloxy)biphenyl-4-carboxylate was used. Room-temperature spontaneous polarization of the monoacrylate was measured to be 190 nC/cm2. The monoacrylate was provided with 10% LC diacrylate. Afte…
We have fabricated subwavelength diffractive optical elements with binary phase profiles for operation at 975 nm. The individual surface-relief features of the elements are smaller than the wavelength of light in the material. By modulating the size and spacing of the features we form artificial, gradient, effective i…
The structure of the thermodynamically most stable form of phosphorus pentoxide, o'-(P 2 O 5 )∞, consists of infinite layers built from six-membered rings of three-corner linked PO 4 - tetrahedra, as described in 1964 by Cruickshank [Acta Cryst. (1964), 17, 679-680]. The P― O bond distances and P-O-P bond angles repor…
Theoretical and experimental advances in the techniques available for solving crystal structures have led to the development of several powerful techniques for solving complex structures, including those of proteins. In this 1995 book, Michael Woolfson and Fan Hai-Fu describe all the available methods and how they are…
We demonstrate a technique to study self-diffusion in germanium, using isotope heterostructures ${(}^{70}$Ge${/}^{74}$Ge). After interdiffusing the nominally undoped layers of $^{70}\mathrm{Ge}$ and $^{74}\mathrm{Ge}$ at temperatures between 543 and 690 \ifmmode^\circ\else\textdegree\fi{}C, the diffusion profiles are…
We perform tight-binding estimates and linear muffin-tin-orbital calculations of the ${\mathrm{\ensuremath{\Delta}}}_{0}$, ${\mathrm{\ensuremath{\Delta}}}_{0}^{\ensuremath{'}}$, and ${\mathrm{\ensuremath{\Delta}}}^{\mathrm{\ensuremath{-}}}$ spin-orbit coupling parameters of II-VI zinc-blende materials. Good agreement…
Sonoluminescence (SL), the phenomenon of light emission associated with the collapse of bubble oscillating under ultrasonic pressure field has been studied by solving the conservation equations for the gas inside bubble analytically. Heat transfer in the liquid layer adjacent to the bubble wall has also been considere…
Conductivity and field-effect mobility measurements using metal-insulator-semiconductor field-effect-transistor devices and acceptor density measurements using metal-insulator- semiconductor (MIS) diodes are presented. The measurements were made on thin polymer films of the organic semiconductor, poly(β′-dodecyloxy-α,…
Two important observations for porous silicon, the saturation and the voltage selective quenching of photoluminescence, are presented. Their similarities are pointed out and discussed in two phenomenological models: the saturation of the absorption and an Auger effect. The consequences of carrier accumulation in quant…
The experimental work by Levine and Bethea [J. Chem. Phys. 65, 2429 (1976)] and by Ward and Miller [Phys. Rev. A 19, 826 (1979)] on the hyperpolarizability of solvated water and water in the gas phase, respectively, showed a very substantial effect of the solvent on the measured hyperpolarizability. The sign of the hy…