Materials Literature
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The adsorption, thermoreactions, and photoreactions of NO coadsorbed with potassium on Si(111)7×7 at 90 K have been investigated using work-function measurements, high-resolution electron energy loss spectroscopy, and mass spectrometry. A minimum in the work function of Si(111)7×7 at 90 K vs the potassium exposure is…
Using the energy transfer parameters deduced from the study on nonexponential luminescence decay of the 4F3/2 level of Nd3+ in YAG at room temperature, it is shown that up to 1.5 at. % Nd, the relative quantum efficiency is reduced by an amount of 18.2C, C being the relative (to Y3+) Nd concentration. It is pointed ou…
Heat capacity measurements of four lanthanide sesquisulfides La2S3, Ce2S3, Nd2S3, and Gd2S3, prepared in the γ phase, have been obtained between 6 and 350 K by adiabatic calorimetry. The total heat capacity has been resolved into lattice, electronic, magnetic, and Schottky components. The Schottky contributions agree…
A new type of superlattice, a Fibonacci acoustic superlattice, is presented. Its ultrasonic spectrum, which is excited by the piezoelectric effect, has been studied theoretically and experimentally. The results are in good agreement with each other.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotoreduction fluorescence detection of quinones in high-performance liquid chromatographyJames R. Poulsen and John W. BirksCite this: Anal. Chem. 1989, 61, 20, 2267–2276Publication Date (Print):October 15, 1989Publication History Published online1 May 2002Published inissue…
We present an ab initio calculation of polarizability and second hyperpolarizability for the benzene molecule including electron–electron correlation. The finite field method is used. For each selected strength of the applied electric field the energy of the benzene molecule is calculated using the self-consistent fie…
The effect of hydrostatic pressure on the lowest direct gaps ${E}_{a}$ (${\ensuremath{\Gamma}}_{2}^{v}$\ensuremath{\rightarrow}${\ensuremath{\Gamma}}_{3}$,${2}^{\mathrm{c}}$) and ${E}_{b}$ (${\ensuremath{\Gamma}}_{2}^{v}$\ensuremath{\rightarrow}${\ensuremath{\Gamma}}_{3}$,${1}^{\mathrm{c}}$,${\ensuremath{\Gamma}}_{1}^…
Fourier transform infrared multiple specular reflectance (FTIR-MSR) spectroscopy has been applied to study the chemisorption of n-hexadecanoic or palmitic acid [CH3(CH2)14COOH] on aluminium as a function of surface coverage. The intensity of the symmetric carboxylate stretching vibration has been used to estimate the…
We present data on the electro-optics and the display performance of liquid-crystal devices based on the distorted helix ferroelectric (DHF) effect which demonstrate TV switching rates and low driving voltages. The DHF effect is based on S*c ferroelectric liquid crystals with very short pitch, which form in suitable c…
Results are presented on a Raman study of diamond films prepared by the filament-assisted chemical vapor deposition technique from a methane-hydrogen gas mixture. It is shown that Raman spectroscopy is a useful probe of both the phase of carbon present and of the quality of the diamond component in the films. The stud…
B2H4 has been produced by the reaction of F atoms with B2H6, in successive abstraction reactions. The B2H4 species was detected and analyzed by photoionization mass spectrometry. The adiabatic ionization potential of this species (9.70±0.02 eV) and the vertical value (∼10.4 eV) are obtained from the photoion yield cur…
The fracture process in ceramic materials upon impact loading is complex in nature. Most often, the brittle ceramic deforms inelastically due to microcracking under shock (compression) loading. At high-velocity impact, the shock generated microcracks rapidly open and extend under subsequent tension (due to the release…
We have demonstrated that single point diamond turning can be used to generate high optical quality finished surfaces on a new organic nonlinear crystal, L-arginine phosphate (LAP). The proper choice of cutting conditions can produce surfaces with <5-A rms local roughness. Local softening or melting near the cutting t…
We have measured inelastic-electron-scattering spectra of several hexagonal-boron-nitride samples with momentum transfer both in and out of the a-b plane and obtained the dielectric and optical constants from 0 to 60 eV. The low-q energy-loss spectrum with momentum in the plane is dominated by the \ensuremath{\pi}-ele…
An increase of the room-temperature band gap from 4.23 to 4.96 eV is observed in crystals of the superionic material yttria-stabilized cubic zirconia (YSZ) when the crystals are reduced either electrolytically or in a hydrogen atmosphere. The original absorption edge of 4.23 eV in unreduced YSZ can be accounted for by…
Our recently developed RISM integral equation theory of the structure and thermodynamics of homopolymer melts is generalized to polymer mixtures. The mean spherical approximation (MSA) closure to the generalized Ornstein–Zernike equations is employed, in conjunction with the neglect of explicit chain end effects and t…
It is known experimentally that Heusler alloys, Ni 2 MnGa and Co 2 NbSn undergo the cubic-to-tetragonal lattice transformation, in a ferromagnetic state and a paramagnetic one, respectively. We calculated electronic structures of Co 2 NbSn and Ni 2 MnGa for both cubic and tetragonal structures by KKR method. Comparing…
The rate of reaction for oxidation of CO over (210) and (111) single-crystal surfaces of platinum has been studied as a function of reactant pressures (PO2,PCO) and sample temperature (T), both experimentally and by computer simulation. Experimental results on both surfaces show regions with a steady high rate of reac…
A direct comparison of the infrared-active vibrational (IRAV) modes in heavily doped, lightly doped, and photoexcited trans-(CH${)}_{\mathrm{x}}$ is presented. The infrared absorption spectrum of heavily doped trans-(CH${)}_{\mathrm{x}}$ exhibits doping-induced IRAV modes and an onset of electronic absorption which ar…
Properties of one-dimensional quasiperiodic discrete Schr\"odinger equations are analyzed by means of a finite-size scaling of the spectrum and the wave function. The incommensurate Harper model, which has only one Fourier component in the potential, is analyzed as an example, and some quantitative results, which are…