Materials Literature
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The early stages of liquid crystal phase ordering upon thermal quenches of isotropic phases into unstable and metastable temperature ranges is studied using two-dimensional (2D) computational solutions of the governing Landau-de Gennes (L-dG) equations for low molar mass nematic liquid crystals and analysis based on t…
We fabricated 4.75in. diagonal field emitter arrays with a double-gated structure in which the carbon nanotubes were synthesized by chemical vapor deposition using CO and H2 as feed gases. The nanotubes grown directly inside gate holes were used as an emitter. The diameter of the gate hole opening was as small as 4μm,…
The magnon dispersion in the charge, orbital, and spin ordered phase in La1/2Sr3/2MnO4 has been studied by means of inelastic neutron scattering. We find excellent agreement with a magnetic interaction model based on the CE-type superstructure. The magnetic excitations are dominated by ferromagnetic exchange parameter…
Abstract A novel potassium borate, KB 3 O 4 (OH) 2 , has been hydrothermally synthesized and structurally characterized by single crystal X‐ray diffraction, FTIR and thermogravimetric analysis. The compound crystallizes in the tetragonal system, space group P 4/ ncc (No. 130), a = 11.3482(3) Å, b = 11.3482(3) Å, c = 1…
The electronic states of $\mathrm{Cd}\mathrm{S}∕\mathrm{Cd}\mathrm{Se}∕\mathrm{Cd}\mathrm{S}$ colloidal nanocrystal quantum-dot quantum wells are studied by large-scale pseudopotential local density approximation (LDA) calculations. Using this approach, we determine the effects of CdS core size, CdSe well thickness, a…
We studied an evolution of local structure and medium-range ordering in relaxor ferroelectric Pb(Zn1∕3Nb2∕3)O3 (PZN) from 550 to 15K using neutron pair distribution function analysis. We show that the local structure of PZN is distorted at all temperatures studied. With decreasing temperature, a medium-range ordering…
Three kinds of magnetic nanoparticle, tetraheptylammonium capped nanoparticles of Fe(3)O(4), Fe(2)O(3) and Ni have been synthesized, and the synergistic effect of these nanoparticles on the drug accumulation of the anticancer drug daunorubicin in leukaemia cells has been explored. Our observations indicate that the en…
A biocompatible interface was constructed on a microchip by using the layer-by-layer (LBL) assembly of charged polysaccharides incorporating proteases for highly efficient proteolysis. The controlled assembly of natural polyelectrolytes and the enzyme-adsorption step were monitored by using a quartz-crystal microbalan…
Silver chloride/polyaniline (PANI) core-shell composites were synthesized through a facile one-step process in the presence of polyvinylpyrrolidone (PVP). PVP not only acted as an anchor agent leading to the formation of the core-shell structure but also prevented the aggregation of PANI efficiently. Transmission elec…
We report on intrinsic p-type ZnO thin films by plasma-assisted metal-organic chemical vapor deposition. The optimal results give a resistivity of 12.7Ωcm, a Hall mobility of 2.6cm2∕Vs, and a hole concentration of 1.88×1017cm−3. The oxygen concentration is increased in the intrinsic p-type ZnO, compared with the n-typ…
Fully epitaxial magnetic tunnel junctions (MTJs) were fabricated with a Co-based full-Heusler alloy Co2Cr0.6Fe0.4Al (CCFA) thin film, whose composition was close to the stoichiometric one, and a MgO tunnel barrier. Cross-sectional high-resolution transmission electron microscope observations indicated that all layers…
The interface capacitance model is briefly revised. It is emphasized that this is a device model related to the boundary condition for polarization and unable to explain the thickness evolution of the ferroelectric properties. The model can be applied to extract the properties of the film from those measured in the ca…
As-synthesized ZnO nanostructures with a bladed bundle-like architecture have been fabricated from a flower-like precursor ZnO.0.33ZnBr(2).1.74H(2)O via a mechanism of dissolution-recrystallization. Experimental conditions, such as initial reactants and reaction time, are examined. The results show that no bladed bund…
The origin and stability of luminescence are critical issues for Si nanocrystals which are intended for use as biological probes. The optical luminescence of alkyl-monolayer-passivated silicon nanocrystals was studied under excitation with vacuum ultraviolet photons (5.1–23eV). Blue and orange emission bands were obse…
ZnO thin films have been grown along the nonpolar [101¯0] direction by metal organic vapor phase epitaxy. The ZnO (101¯0) surface develops well defined facets. The orientation of the topographic normals reveals that the inclination angle of the facets increases as thicker films are considered, attaining a maximum valu…
We introduce active negative-index metamaterials based on left-handed nonlinear transmission line media and measure a greater than 10dB amplification of a weak signal wave at the output of the transmission line due to its parametric interaction with an intensive pump wave, by which energy in a pump wave at one frequen…
Low-frequency noise spectral density in chalcogenide-based phase-change memory cells has been measured, discussing the role of trapping centers and static disorder as responsible for a noise level in the vitreous insulating state two orders of magnitude higher than in the ordered conducting polycrystalline one. The ma…
Carbon nanofibres aerosolized by the agitation of as-produced commercial powder have been characterized in situ by using the differential mobility analyser-aerosol particle mass analyser (DMA-APM) method to determine their structural properties such as the effective density and fractal dimension for toxicology study.…
The one-dimensional fragmentation of a dynamically expanding ring (Mott’s problem) is studied numerically to obtain the fragment signatures under different strain rates. An empirical formula is proposed to calculate an average fragment size. Rayleigh distribution is found to describe the statistical properties of the…
Rings of bundled single-walled carbon nanotubes with perfectly toroidal geometries (see figure), are fabricated in high yields by a floating chemical vapor deposition process involving the thermal decomposition of acetylene. The nanotube rings can be grown with varying densities on a wide variety of substrates at rela…