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。
A two-dimensional Euclidean plane can be identified with the Gauss-Argan plane, so that a two-dimensional triangular lattice can be identified, apart from a scaling factor, with a set of 'triangular integers' of the complex quadratic field associated with a complex cubic root of 1. It is shown that a two-dimensional m…
The luminescence spectra and decay curves of Sb 3+ -doped Cs 2 NaMBr 6 (M=Sc,Y,La) are presented. In this lattice the Sb 3+ ion (5s 2 ) is octahedrally surrounded by six bromide ions. The emission consists of one band. The Stokes shift increases in going from Sc to La. This is connected to the larger space available f…
((NH4)1–xKx)2SO4 powdered crystals with x = 0.0, 0.1, 0.15, 0.25, 0.32, 0.6, 0.7, and 1.0 are studied by X-ray diffraction from room temperature down to 73 K. It is found that the mixed crystals are isomorphous to (NH4)2SO4 and K2SO4. The phase transition temperature decreases with the increase of the substituted ions…
Cross-slip of partial dislocations via the formation of stair rod dislocations at the line of intersection of two {111} planes is studied. General formulae are derived for the calculation of activation energies. It is shown that local stress concentrations due to a pile-up or a microtwin tip makes such cross-slip proc…
Magnetic susceptibility of an organic ion-radical salt, triethylammonium[TCNQ] 2 , has precisely been measured in the temperature range between 4.2 and 360K. It shows a shallow but obvious dip near 215 K. Such anomaly in the susceptibility of the salt has been found for the first time. The anomaly may result from the…
ABSTRACT This paper describes a recently developed standardized system for dull grading natural diamond, PDC, and TSP (Thermally Stable Polycrystalline diamond) bits, otherwise known as fixed cutter bits. The new system is consistent with the recently revised dull grading system for roller bits. It describes the condi…
The transmission spectra of the amorphous semiconductor system (${\mathrm{GeS}}_{2}$${)}_{\mathrm{x}}$(${\mathrm{As}}_{2}$${\mathrm{S}}_{3}$${)}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$ are measured under hydrostatic pressure, and the dependence of the optical gap ${E}_{0}$ and the refractive index n on the pressure is s…
The CNDO/S3 molecular orbital model is applied to describe the electronic structure of aniline, (C6H5)NH2, emeraldine, (C6H5)N(C6H4)N(C6H4)NH(C6H4)NH2, its hydrogenated and dehydrogenated forms, and its singly and doubly protonated forms. The cation eigenvalue spectrum, i.e., density of valence states (DOVS), is found…
A recombinant plasmid carrying an 11 kb restriction-endonuclease-ClaI fragment of genomic DNA from Escherichia coli ML308 was constructed. This plasmid complements an aceA mutation. The plasmid encodes the structural genes of the glyoxylate bypass operon, namely malate synthase A (aceB), isocitrate lyase (aceA) and is…
X-ray scattering and electron-transmission microscopy of melt-spun Al-Si-Mn alloys reveal that the Al-Mn icosahedral phase itself can grow congruently over a range of composition varying from 16 to 20 at.?Mn, and Si atoms substitute Al atoms selectively. The Q dependences of linewidth \ensuremath{\Delta}Q suggest that…
Thin films of the C1b-phase Heusler alloy PtMnSb, prepared by rf sputtering and subsequent annealing, have been studied in order to assess the high magneto-optical Kerr effect of this compound. The room-temperature saturation magnetization (Ms) and coercive force (Hc) for PtMnSb thin films after being annealed at 500…
We present a model to explain the resonances in the photoemission cross section of a surface state as a function of photon energy. The model is based on an extension of the direct-transition model for bulk states, and should be applicable to a surface state with a long decay length. Energy broadening of the final stat…
Raman scattering and infrared studies are reported for the layer compound GaSe under hydrostatic pressures up to 4 GPa. The rigid-layer mode shifts towards higher frequencies with an initial pressure coefficient of 0.234 ${\mathrm{GPa}}^{\mathrm{\ensuremath{-}}1}$. The overall behavior is explained in terms of the vol…
Localized 3p excitations and their decay have been studied in 3d transition metals and their single-crystal oxides by using electron-energy-loss (EELS), photoemission, and resonant photoemission spectroscopies. Variation of the primary-electron-beam energy in EELS allows the resolution of threshold transitions from hi…
New series of ferroelectric liquid crystals with two chiral carbons or bulky molecular components at the chiral carbon are synthesized and are found to possess extremely large spontaneous polarization exceeding 2×10−7 C/cm2 and a dielectric constant larger than 7000. These compounds are stable and exhibit a novel diel…
We have found that decagonal quasicrystal and 10-fold twins of monoclinic ${\mathrm{Al}}_{13}$${\mathrm{Fe}}_{4}$ coexist in rapidly cooled Al-Fe alloy. The tenfold axis of the decagonal phase is parallel to the pseudotenfold [010] axis of the twins. There is good coincidence between the strong spots of the decagonal…
We have obtained Raman spectra of phase-I, -II, and -III ${\mathrm{KNO}}_{3}$ films 0.26 \ensuremath{\mu}m thick. The primary aim was to establish the physical mechanism for stabilization of the ferroelectric phase III in thin films. In bulk, phase III exists only as a reentrant phase stable from \ensuremath{\sim}113…
Epitaxial growth of SrO thin films onto Si(111) and (100) substrates by means of molecular-beam epitaxy has been demonstrated. The orientation relationships between epitaxial SrO and Si were found to be (111)SrO//(111)Si and [112̄]SrO//[112̄]Si, (100)SrO//(100)Si and [011]SrO//[001]Si. The composition of the grown fil…
The size dependence of the lowest electron-hole state in semiconductor microcrystals is calculated using the variational principle with a three-parameter Hylleraas-type wave function. For very small particles the Coulomb interaction may be treated as a perturbation. For larger particles the size dependence of the ener…
A new investigation of the optical properties of scandium is presented. Near-normal-incidence reflectivity measurements were performed from 0.22 to 5.5 eV on polycrystalline thin films evaporated in situ in ultrahigh vacuum. The reflectivity, from 0.22 to 35 eV, of the same samples after they had been exposed to air w…