Materials Literature
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In this communication, gold nanoparticles with a tadpole shape were synthesized by a simple aqueous-phase chemical method. The unusual three-dimensional and crystallized structures were demonstrated by TEM, AFM, and HRTEM methods. The SEM and UV-visible absorption measurements and electrophoresis experiments revealed…
The preparation of nanocomposite materials from carbon nanotubes (CNTs) and metal or metal oxide nanoparticles has important implications to the development of advanced catalytic and sensory materials. This paper reports findings of an investigation of the preparation of nanoparticle-coated carbon nanotube composite m…
Room-temperature reactions of 46 different atomic cations with N 2 O have been surveyed systematically using an inductively coupled plasma/selected-ion flow tube (ICP/SIFT) tandem mass spectrometer. The atomic cations are produced at about 5500 K in the ICP source and are allowed to decay radiatively and thermalize by…
Electron energy-loss spectrometry was employed to measure the white lines at the ${L}_{2,3}$ absorption edges of the $3d$ transition-metal oxides and lithium transition-metal oxides. The white-line ratio $({L}_{3}∕{L}_{2})$ was found to increase between ${d}^{0}$ and ${d}^{5}$, and decrease between ${d}^{5}$ and ${d}^…
We investigate the depinning transition occurring in dislocation assemblies. In particular, we consider the cases of regularly spaced pileups and low-angle grain boundaries interacting with a disordered stress landscape provided by solute atoms, or by other immobile dislocations present in nonactive slip systems. Usin…
Bravais' rule, of wide validity for crystals, states that their surfaces correspond to the densest planes of atoms in the bulk. Comparing a theoretical model of icosahedral Al-Pd-Mn with experimental results on sputter-annealed surfaces, we find that this correspondence breaks down, i.e., the surfaces parallel to the…
Multi-subband effect on spin precession and spin dephasing in $n$-type GaAs quantum wells is studied with electron-electron and electron-phonon scattering explicitly included. The effects of temperature, well width and applied electric field (in hot-electron regime) on the spin kinetics are thoroughly investigated. It…
Electronic structure calculations for layered zincblende semiconductors are described within a restricted basis formalism which naturally and non-perturbatively accomodates both crystalline inversion asymmetry and cubic anisotropy. These calculations are applied to calculate the electron spin decoherence times $T_1$ a…
Measurements on 'free-standing' single crystal barium titanate capacitors with thicknesses down to 75nm show a dielectric response typical of large single crystals rather than conventional thin films. There is a notable absence of any broadening or temperature shift of the dielectric peak or loss tangent. Peak dielect…
We have developed a simple precipitation route to synthesize magnetite (Fe3O4) nano-particles with controlled size without any requirement of calcination step at high temperatures. The study of these nano-particles indicates an enhancement in saturation magnetization with reduction in size down to ~10 nm beyond which…
A theory of spin-dependent electron transmission through resonant tunneling diode (RTD) grown of non-centrosymmetrical semiconductor compounds has been presented. It has been shown that RTD can be employed for injection and detection of spin-polarized carriers: (i) electric current flow in the interface plane leads to…
Using a combination of first-principles and effective-Hamiltonian approaches, we map out the structure of ${\text{BaTiO}}_{3}$ under epitaxial constraints applicable to growth on perovskite substrates. We obtain a phase diagram in temperature and misfit strain that is qualitatively different from that reported by Pert…
Isocitrate dehydrogenases (IDHs) catalyze the oxidative decarboxylation of isocitrate to alpha-ketoglutarate, and regulation of the enzymatic activity of IDHs is crucial for their biological functions. Bacterial IDHs are reversibly regulated by phosphorylation of a strictly conserved serine residue at the active site.…
Zinc oxide is a unique material that exhibits semiconducting and piezoelectric dual properties. Using a solid–vapour phase thermal sublimation technique, nanocombs, nanorings, nanohelixes/nanosprings, nanobelts, nanowires and nanocages of ZnO have been synthesized under specific growth conditions. These unique nanostr…
Integrated microstructural observations, X-ray powder diffractometric (XRPD) modal composition, illite Kubler index and chlorite “crystallinity” determinations and vitrinite reflectance measurements were carried out on marly slates from selected profiles of the Helvetic zone of the Central Alps, Switzerland. The studi…
Polymer crystallization is discussed in the context of nonequilibrium structure formation. In particular, we focus on the morphogenesis of polymer crystals during growth and annealing processes. We combine observations on quasi-two-dimensional polymer films, mainly obtained with atomic force microscopy, with computer…
Abstract A simple, productive, low-cost route has been developed to synthesize the high-quality 1-D nanorods of CdE (E = Se, Te) with 3–8 nm in diameter and 5–40 nm in length using myristic acid as a complexing agent. Moreover, the reaction is performed under mild conditions and relatively low temperatures. The X-ray…
Abstract Chiral [2.2]metacyclophan-1-ene undergoes an enantiospecific photochromic reaction along with a photoreversible optical rotation change at the wavelength where both photoisomers never absorb. This enables us to carry out a non-destructive read-out of the photomemory made by the photochromic [2.2]metacyclophan…
The crystal structure of filatovite, K[(Al,Zn) 2 (As,Si) 2 O 8 ] (monoclinic, I 2/ c , a = 8.772(1), b = 13.370(2), c = 14.690(2) A, β = 115.944(6)°, V = 1549.1(4) A 3 ) has been solved by direct methods and refined to R 1 = 0.033 on the basis of 1959 unique observed reflections with | F o | ≥ 4σ F . It is isotypic wi…
Abstract We describe the synthesis of water-soluble PEGylated semiconductor nanocrystals and the characterization of their optical properties and colloidal stability by fluorescence and UV spectrometers. The fluorescence intensity of PEGylated CdSe/ZnS in PBS buffer was observed to be 75% of the initial values of conv…