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 present an X-ray absorption spectroscopy study of Ni c Mg 1-c O (0.01<or=c<or=1) solid solutions on the Ni K edge. The analysis of XANES and EXAFS regions allowed us to obtain the following results. The nickel ions are located in a distorted environment and shift upon dilution to the off-centre positions. In the fi…
We present the first $^{13}\mathrm{C}$ NMR measurements carried out in the superconducting state of a two-dimensional organic superconducting single crystal. Spin lattice relaxation rate and Knight shift are reported for magnetic fields parallel and perpendicular to the conducting layers. For perpendicular fields, the…
Theoretical results for the temperature dependence of the thermal expansion coefficient for 3C–SiC are reported using a phenomenological lattice dynamical theory in the quasiharmonic approximation. The linear thermal expansion coefficient α of 3C–SiC exhibits a variation with temperature much like that of the specific…
We develop rigorous bounds on the effective thermal conductivity ${\ensuremath{\sigma}}_{e}$ of dispersions that are given in terms of the phase contrast between the inclusions and matrix, the interface strength, volume fraction, and higher-order morphological information, including interfacial statistics. The new bou…
Materials with desirable properties may be created through control of crystal size and shape and assembly of such crystals into more complex arrangements. In his Perspective, Heath discusses recent work reported in this issue by Murray et al . ( p. 1335 ) in which nanocrystals of cadmium selenide were formed into orde…
The self-organization of CdSe nanocrystallites into three-dimensional semiconductor quantum dot superlattices (colloidal crystals) is demonstrated. The size and spacing of the dots within the superlattice are controlled with near atomic precision. This control is a result of synthetic advances that provide CdSe nanocr…
Following Sham and Rice [L. J. Sham, T. M. Rice, Phys. Rev. 144 (1966) 708] the correlated motion of particle-hole pairs is studied, starting from the general two-particle Greens function. In this way we derive a matrix equation for eigenvalues and wave functions, respectively, of the general type of collective excita…
By combining the Self-Interaction Correction (SIC) with pseudopotential perturbation theory, the role of self-interaction errors inherent to the Local Density Approximation (LDA) to Density Functional Theory is estimated in the determination of ground state and low energy isomeric structures of small metallic clusters…
Molecular dynamics has been used to study the wetting of model polymer surfaces, the crystal surfaces of polyethylene (PE), poly(tetrafluoroethylene) (PTFE), and poly(ethylene terephthalate) (PET) by water and methylene iodide. In the simulation a liquid droplet is placed on a model surface and constant temperature, r…
Recent measurements of the scattering of He and Ne atoms at Rh(110) suggest that these two rare-gas atoms measure a qualitatively different surface corrugation: While Ne atom scattering seemingly reflects the electron-density undulation of the substrate surface, the scattering potential of He atoms appears to be antic…
Using density-functional-theory we study the electronic and structural properties of a monolayer of Cu on the fcc (100) and (111) surfaces of the late 4d transition metals, as well as a monolayer of Pd on Mo bcc(110). We calculate the ground states of these systems, as well as the difference of the ionization energies…
Abstract The characterization of KEVLAR‐29 fibers has been performed by studying their interactions with three model compounds in gaseous form. Water, aniline, and epoxystyrene were used for this purpose. The effects on the nature of these interactions of two types of surface engineering, namely the coating with an ep…
Abstract The surface grafting of polymers onto carbon thin film deposited on a glass plate was achieved by two methods: the graft polymerization initiated by initiating groups introduced onto the surface; and the trapping of polymer radicals by surface aromatic rings of the thin film. It was found that the radical and…
Abstract Differential scanning calorimetry (DSC) was used to analyze the crystal distribution in homogeneous ethylene–octene copolymers polymerized by the constrained geometry catalyst technology (CGCT). To minimize ambiguities from thermal history effects, copolymers were isothermally annealed at temperatures within…
Equations of motion for model colloidal particles are derived, which include a mean-field local density representation for the many-body-hydrodynamics (MBH) interactions. These are implemented as a modification of Ermak's 1975 Brownian dynamics free-draining algorithm, with a local density prescription for the frictio…
The magnetic properties and microstructures of rapidly quenched Sm–Fe–N powders with low Sm contents and Zr and Co addition have been studied. High remanence values of 9.4 kG with high HcJ values of 7–10 kOe were obtained for isotropic powders. The x-ray diffraction analysis and transmission electron microscopy (TEM)…
We present experimental studies of the growth of 3D xenon dendrites into a supercooled pure melt. The shape of the dendrite tip and the origin of the sidebranching is investigated. The shape in the tip region is not axisymmetric and four fins grow along the dendrite. Sidebranches develop at the ridges of these fins. T…
A mixture of methane, hydrogen, and oxygen has been used to etch thin films of NiFe. The variation of etch rate with concentration of methane and oxygen has been investigated. By using a SrF2 mask, patterned by liftoff, small micrometer-sized elements have been fabricated. It is demonstrated that the use of CH4/H2/O2…
The dark conductivity and transient photoconductivity measurements on thin films of a-Se 80-x Te x Ga 20 (0<or=x<or=20) have been reported in the temperature range from 148 to 318 K. The results indicate that, at higher temperatures, hopping conduction takes place in the tail states. At lower temperatures the conducti…
Polycrystalline pyrolytic graphite was compressed in a diamond anvil cell to pressures up to 73 GPa. In situ Raman measurements reveal evidence of a phase transition at 15-20 GPa, consistent with earlier static high-pressure experiments on graphite. The sample was quenched by rapid downloading of the cell to ambient p…