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 metamaterial (MM) differs from an ordinary optical material mainly in that it has a dispersive magnetic permeability and offers greatly enhanced design freedom to alter the linear and nonlinear properties. This makes it possible for us to control the propagation of ultrashort electromagnetic pulses at will. Here we…
No family resemblance: IR photodissociation experiments and DFT optimizations implementing a genetic algorithm suggest that small aluminum oxide clusters have unusual structures in the gas phase. For example, the structure proposed for [(Al2O3)4]+ (see picture; Al black, O gray) has no features in common with bulk alu…
In a rather contradictory situation regarding magnetic data on Co-doped ZnO, we have succeeded in fabricating high-quality single crystalline Zn(1-x)Co(x)O (x=0.003-0.07) thin films. This gives us the possibility, for the first time, to examine the intrinsic magnetic properties of ZnO:Co at a quantitative level and th…
Sound effects: Multilayered capsules, such as that shown in the SEM image, are promising vehicles for the delivery of macromolecular drugs. Ultrasonic irradiation can be used to trigger the release of encapsulated species from capsules fabricated using layer-by-layer technology. Ultrasound affects the integrity of the…
Transport properties through wide and short ballistic graphene junctions are studied in the presence of arbitrary dopings and magnetic fields. No dependence on the magnetic field is observed at the Dirac point for any current cumulant, just as in a classical diffusive system, both in normal-graphene-normal and normal-…
Three-terminal devices with conduction channels formed by quasi-metallic carbon nanotubes (CNTs) are shown to operate as nanotube-based field-effect transistors under strong magnetic fields. The off-state conductance of the devices varies exponentially with the magnetic flux intensity. We extract the quasi-metallic CN…
Abstract Surface charged iron oxide (Fe 3 O 4 ) nanoparticles were used for the synthesis of sulfonated polyaniline (SPAN)‐Fe 3 O 4 nanocomposites (SPAN/Fe 3 O 4 ‐NCs). 2,5‐diaminobenzenesulfonic acid (DABSA) and 2‐aminobenzenesulfonic acid (ABSA) were independently polymerized with aniline to form SPAN. The structure…
Abstract Three different kinds of nanoparticles for paracellular transport were prepared using a simple and mild ionic‐gelation method. Sodium tripolyphosphate (TPP) as crosslinking agent was added into three kinds of solutions, which were chitosan solution, physical blending solution of chitosan, and glycidyl trimeth…
We introduce a new technique for measurement of the thermal conductivity of ultrathin films of single-walled carbon nanotubes (SWNTs) utilizing IR radiation as heat source and the SWNT film as thermometer. The technique is applied to study the temperature dependence of the thermal conductivity of an as-prepared SWNT f…
Using a realistic microscopic model, we study the electric and magnetic properties of the interface between a half-metallic manganite and an insulator. We find that the lack of carriers at the interface attenuates the double-exchange mechanism, weakening the ferromagnetic coupling between the Mn ions. In this situatio…
The detailed evolution of the magnitude of the local Jahn-Teller (JT) distortion in La(1-x)Ca(x)MnO3 is obtained across the phase diagram for 0< or =x< or =0.5 from high-quality neutron diffraction data using the atomic pair distribution function method. A local JT distortion is observed in the insulating phase for al…
Grain boundaries are the most inevitable and pronounced structural defects in pentacene films. To study the effect of those structural defects on the electronic state distribution, the energy levels of a hole on molecules at and near the defect have been calculated using a submolecular self-consistent-polarization-fie…
Current methods for producing single-walled carbon nanotubes (SWNTs) lead to heterogeneous samples containing mixtures of metallic and semiconducting species with a variety of lengths and defects. Optical detection at the single nanotube level should thus offer the possibility to examine these heterogeneities provided…
Two fundamental extensions to the function of previously described fully field effect two-dimensional (2D) electron heterostructures are presented: First, using the same basic heterostructure design of lithographically defined contacts overlain by both an insulating layer and top-gate employed for electron systems, ap…
The ground state phase diagram of the half-filled repulsive Hubbard model in a bilayer is investigated using cluster dynamical mean field theory. For weak to intermediate values of Coulomb repulsion $U$, the system undergoes a transition from a Mott insulating phase to a metallic phase and then onto a band insulating…
Abstract The thermal degradation of chitosan at different heating rates B in nitrogen was studied by thermogravimetric analysis. The results indicate that the thermal degradation of chitosan in nitrogen is a one‐step reaction. The degradation temperatures increase with B . Experimentally, the initial degradation tempe…
Dielectric responses have been investigated on the triangular-lattice antiferromagnet $\mathrm{Cu}\mathrm{Fe}{\mathrm{O}}_{2}$ and its site-diluted analogs $\mathrm{Cu}{\mathrm{Fe}}_{1\ensuremath{-}x}{\mathrm{Al}}_{x}{\mathrm{O}}_{2}$ ($x=0.01$ and 0.02) with and without the application of the magnetic field. We have…
We report on the metalorganic chemical vapor deposition of $\mathrm{GaN}:\mathrm{Fe}$ and $(\mathrm{Ga},\mathrm{Fe})\mathrm{N}$ layers on $c$-sapphire substrates and their thorough characterization via high-resolution x-ray diffraction, transmission electron microscopy (TEM), spatially resolved energy dispersive x-ray…
This paper presents a numerical implementation of a first-principles envelope-function theory derived recently by the author [B. A. Foreman, Phys. Rev. B 72, 165345 (2005)]. The examples studied deal with the valence subband structure of GaAs/AlAs, GaAs/Al(0.2)Ga(0.8)As, and In(0.53)Ga(0.47)As/InP (001) superlattices…
A small change of basis in k.p theory yields a Kane-like Hamiltonian for the conduction and valence bands of narrow-gap semiconductors that has no spurious solutions, yet provides an accurate fit to all effective masses. The theory is shown to work in superlattices by direct comparison with first-principles density-fu…