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 Antarctic ice diatom Amphiprora kufferathii Manguin is always accompanied by epiphytic bacteria in its natural habitat. To investigate the nature of this relationship, axenic cultures of A. kufferathii were obtained by ampicillin treatment. Diatom cultures without bacteria were less dense. The bacteria were shown…
By investigating wave properties at cloak boundaries, invisibility cloaks with arbitrary shape constructed by general coordinate transformations are confirmed to be perfectly invisible to the external incident wave. The differences between line transformed cloaks and point transformed cloaks are discussed. The fields…
Although short-circuit current is frequently considered the major design fundamental for power transformers, experience with transformer failures shows that inrush currents that occur when transformers are energized can also cause serious damage. To investigate the resultant forces due to energizing power transformer…
The thermal conductance at solid-solid interfaces is becoming increasingly important in thermal considerations dealing with devices on nanometer length scales. Specifically, interdiffusion or mixing around the interface, which is generally ignored, must be taken into account when the characteristic lengths of the devi…
Application of bis(propylenedioxythiophene) (bis(ProDOT)) π-conjugated bridges bearing alkyl or aryl substituents in electro-optic (EO) chromophores is presented. A series of three bis(ProDOT)-based chromophores and a bithiophene-based control chromophore were prepared and fully characterized with regard to EO applica…
Polarizability of noninteracting 2D Dirac electrons has a 1/square root(qv-omega) singularity at the boundary of electron-hole excitations. The screening of this singularity by long-range electron-electron interactions is usually treated within the random phase approximation. The latter is exact only in the limit of N…
A series of Zn(1-x)Co(x)O nanorods with dopant content ranging from x = 0.00 to 0.10 was prepared by a wet chemical method. All Zn(1-x)Co(x)O samples were investigated by x-ray diffraction, transmission electron microscopy, energy-dispersion x-ray line mapping analysis, and UV-visible absorption spectroscopy. It was f…
We study Kolmogorov-Johnson-Mehl-Avrami (KJMA) theory of phase conversion in finite volumes. For the conversion time we find the relationship $τ_{\rm con} = τ_{\rm nu} [1+f_d(q)]$. Here $d$ is the space dimension, $τ_{\rm nu}$ the nucleation time in the volume $V$, and $f_d(q)$ a scaling function. Its dimensionless ar…
Gallium arsenide nanowires were synthesized by gallium-assisted molecular beam epitaxy. By varying the growth time, nanowires with diameters ranging from 30 to 160 nm were obtained. Raman spectra of the nanowires ensembles were measured. The small line width of the optical phonon modes agree with an excellent crystall…
Ultraviolet-photoemission (UPS) measurements and supporting specific-heat, thermal-expansion, resistivity, and magnetic-moment measurements are reported for the magnetic shape-memory alloy Ni2MnGa over the temperature range 100<T<250 K. All measurements detect clear signatures of the premartensitic transition (T(PM) a…
Cohesive laws are stress-strain curves used in finite element calculations to describe the debonding of interfaces such as grain boundaries. It would be convenient to describe grain boundary cohesive laws as a function of the parameters needed to describe the grain boundary geometry; two parameters in two dimensions a…
We use first-principles density-functional-theory-based calculations to investigate structural instabilities in the high symmetry cubic perovskite structure of rare-earth ($R=\text{La}$, Y, Lu) and Bi-based biferroic chromites, focusing on $\ensuremath{\Gamma}$ and $R$ point phonons of nonmagnetic, ferromagnetic, and…
Aligned carbon nanotube (CNT) arrays were fabricated from a multilayer catalyst configuration by microwave plasma-enhanced chemical vapor deposition (PECVD). The effects of the thickness and annealing of the aluminum layer on the CNT synthesis and thermal performance were investigated. An experimental study of thermal…
Shear localization is a generic feature of flows in yield stress fluids and soft glassy materials but is incompletely understood. In the classical picture of yield stress fluids, shear banding happens because of a stress heterogeneity. Using recent developments in magnetic resonance imaging velocimetry, we show here f…
It has often been suggested that correlation effects suppress the small e_g' Fermi surface pockets of NaxCoO_2 that are predicted by LDA, but absent in ARPES measurements. It appears that within the dynamical mean field theory (DMFT) the ARPES can be reproduced only if the on-site energy of the eg' complex is lower th…
We report on first-principles density functional perturbation theory calculations and inelastic neutron scattering measurements of the phonon density of states, dispersion relations, and electromechanical response of $\mathrm{Pb}\mathrm{Ti}{\mathrm{O}}_{3}$, $\mathrm{Ba}\mathrm{Ti}{\mathrm{O}}_{3}$, and $\mathrm{Sr}\m…
Using the first-principles density-functional approach, magnetic properties of Mn-, Fe-, Co-, and Ni-doped rutile TiO2 were investigated for two different impurity concentrations (25% and 6.25%). Calculations were performed with the Full-Potential Linearized-Augmented Plane Waves (FLAPW) method, assuming that the magn…
In this report we show that in the perovskite manganite La_{1-x}Ca_{x}MnO_3 for a fixed x \approx 0.33, the magnetic transition changes over from first order to second order on reducing the particle size to nearly few tens of a nanometer. The change-over is brought about only by reducing the size and with no change in…
We report an ab-initio comparative study of the electric-field-gradient tensor (EFG) and structural relaxations introduced by acceptor (Cd) and donor (Ta) impurities when they replace cations in a series of binary oxides: TiO2, SnO2, and In2O3. Calculations were performed with the Full-Potential Linearized-Augmented P…
Martensitic and magnetic properties of ferromagnetic shape memory alloys are known to depend up on structural modulations and associated changes in the Fermi surface. These modulations although periodic and spanning over multiple unit cells, involve movement of atoms typically of the order of 0.01A. Therefore X-ray Ab…