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。
Using ${10}^{6}$-atom molecular-dynamics simulations, we investigate dynamic fracture in nanophase ${\mathrm{Si}}_{3}{\mathrm{N}}_{4}$. The simulations reveal that intercluster regions are amorphous, and they deflect cracks and give rise to local crack branching. As a result, the nanophase system is able to sustain an…
Crack propagation in a graphite sheet is investigated with million atom molecular-dynamics simulations based on Brenner's reactive empirical bond-order potential. For certain crystalline orientations, multiple crack branches with nearly equal spacing sprout as the crack tip reaches a critical speed of ${0.6V}_{R}$, wh…
The thermoluminescence (TL) of ZnS nanoparticles is reported. The TL intensity increases as the particle size is decreased. The consistency of the size dependence of the TL with that of the surface fluorescence indicates that the TL may be related to the surface states. TL may be caused by the recombination of carrier…
Laser scanning confocal microscopy has been used to study the time evolution of a three dimensional spatially bicontinuous structure of a phase-separated polymer blend undergoing the late stage of spinodal decomposition, as a model example of condensed matter systems. Both the mean and Gaussian curvatures of the inter…
The carrier transport in different phases of a new photoconductive calamitic liquid crystal, 2-(4\ensuremath{'}-heptyloxyphenyl)-6-dodecylthiobenzothiazole was studied by the time-of-flight technique: In the smectic A phase, a fast hole transient photocurrent was obtained in a nondispersive manner, in which the mobili…
The vacancy in diamond is a fundamental defect which has been studied theoretically and experimentally for forty years. However, although early theories (Coulson C A and Kearsley M J 1957 Proc. R. Soc. A 241 433) were extremely successful in explaining the nature of the ground state of the neutral defect and the Jahn…
We propose that extended orientational correlations can appear at the surface of supercooled heavy noble liquid metals, due to the same compressive forces that cause reconstruction of their crystal surfaces. Simulations for liquid Au show a packed surface layer structurally akin to a defected 2D triangular solid. Upon…
A new kind of scaling analysis for the conductivity spectra of glasses without any arbitrary parameters is presented. By applying this method to sodium borate glasses of different compositions, we find strong indications for the existence of a universal ionic relaxation process as well as for a strong electrolyte beha…
Carbon nanotube sheet electrodes have been prepared from catalytically grown carbon nanotubes of high purity and narrow diameter distribution, centered around 80 Å. Our study shows that the electrodes are free-standing mats of entangled nanotubes with an open porous structure almost impossible to obtain with activated…
Structural changes of the intermetallic compound SmCo5 after hydrogenation and nitrogenation were investigated by x-ray diffraction, transmission electron microscopy, and differential scanning calorimetry. Amorphization was not observed by hydrogenation of SmCo5. On the contrary, an amorphous a-SmCo5N1.2 alloy was syn…
The sandwich-like title complex, hexakis(dimethylformamide)-1κO,2κO,3κO,4κO,5κO,6κO–bis[2,4,6,8,10,12-hexaphenylsiloxane-2,4,6,8,10,12-hexaolato(6−)-1:2κ2O1,2:3κ2O2,3:4κ2O3,- 4:5κ2O4,5:6κ2O5,1:6κ2O6]hexacopper(II) tetrakis(dimethylformamide) solvate, [Cu6(C3H7NO)6{(C6H5)6O12Si6}2].4C3H7NO, is comprised of two regular…
We studied the energy transfer between excitons and the 3d electrons of ${\mathrm{Mn}}^{2+}$ in ${\mathrm{Cd}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$ ${\mathrm{Mn}}_{\mathrm{x}}$ Te crystals within a Mn concentration range of 0.2\ensuremath{\leqslant}x\ensuremath{\leqslant}0.45 at T=2, 5, and 20 K by emission, excitati…
Spin-resolved photoemission spectra of 6-, 9-, and 13-eV satellites of the ferromagnetic Ni valence band are reported. The spin polarization of the valence-band satellites and their photon energy dependence are interpreted by the multiplet configuration of ${3\mathrm{d}}^{8}$ and ${3\mathrm{d}}^{7}$ final states. This…
The title compound, lead(II)dodecabismuth(III) pentamolybdenum(VI) oxide, was prepared by solid-state methods. The structure consists of (Bi12O14)8n+n columns surrounded by (MoO4)2− tetrahedra. The Pb atoms occupy specific sites between four tetrahedra.
Stimulated by recent data for the electron-electron relaxation time measured in two different double-quantum-well systems we consider both intralayer and interlayer screened electron-electron interactions and include a contribution beyond the simple golden-rule result. In particular, we find that (i) including a nongo…
We investigated the Raman spectra of thermally reduced and untreated Y- and Ca-stabilized cubic zirconia. A substantial decrease in Raman activity was observed in the acoustic mode region upon reduction. Analyses of these spectra as a phonon density of states and of the observed spectral changes indicate that the redu…
A theory is presented to study the plasma oscillations of the full \ensuremath{\sigma}+\ensuremath{\pi} electron system of carbon nanotubes. Cylindrical charge density was supposed to represent the electron distribution within the shells of the tubule and an integral equation is derived for the perturbation caused by…
Vitamin E (+/-alpha-tocopherol) was recently investigated as an antioxidant for implanted poly(etherurethane urea) (PEUU) elastomers. In that work, vitamin E prevented chemical degradation of biaxially strained PEUU up to 5 weeks implantation, and prevented pitting and cracking of the PEUU surface for the duration of…
We describe a novel procedure to determine a phase coexistence line by computer simulation. The procedure combines elements of the Clausius–Clapeyron integration technique with free-energy difference calculations. As an application, the phase diagram of a simple hard-core Yukawa model of a charge-stabilized colloid, w…
The electronic level structure and dephasing dynamics of InP nanocrystals in the strong quantum-confinement regime are studied by two complementary techniques: nanosecond hole burning and the femtosecond three-pulse photon echo. Hole burning yields the homogeneous electronic level structure while the photon echo allow…