Materials Literature
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Nanocrystalline undoped and Mn doped zinc sulphide (ZnS) thin films were synthesized by a wet chemical route without using any capping agent. The x-ray diffraction pattern showed the typical interplanar spacings corresponding to the cubic phase of ZnS. Transmission electron microscopy (TEM) studies confirmed the nanoc…
The effect of molecular weight on the solvent-induced self-assembly of mixed poly(methyl methacrylate) (PMMA)/polystyrene (PS) brushes on silicon wafers was studied. For a series of mixed brushes with a fixed PMMA M(n) and systematically changed PS M(n), a transition in water advancing contact angle (theta(a)) from 74…
Colloidally dispersed niobate nanosheets with the thickness of 1.8 nm and controlled mean lateral sizes of 0.15-7.8 mum were prepared and their liquid crystallinity was examined. The nanosheet colloids with different lateral sizes were obtained by exfoliation of single crystals of layered niobate K4Nb6O17 and subseque…
Polyoxometalates (POMs) as a homogeneous photocatalyst and semiconductor oxide as a heterogeneous photocatalyst share many aspects of similarity in their operating mechanisms. This study systematically compares various photocatalytic oxidation and reduction reactions of PW12O403- (a POM) and TiO2 in water to demonstra…
Optical excitations in hexagonal nanonetwork materials, for example, Boron-Nitride (BN) sheets and nanotubes, are investigated theoretically. A permanent electric dipole moment, whose direction is from the B site to the N site, is considered along the BN bond. When the exciton hopping integral is restricted to the nea…
We review calculations and measurements of the phonon-dispersion relation of graphite. First-principles calculations using density-functional theory are generally in good agreement with the experimental data since the long-range character of the dynamical matrix is properly taken into account. Calculations with a plan…
Acoustic Emission (AE) data from single point turning machining are analysed in this paper in order to gain a greater insight of the signal statistical properties for Tool Condition Monitoring (TCM) applications. A statistical analysis of the time series data amplitude and root mean square (RMS) value at various tool…
We have carried out an ultrahigh-field cyclotron resonance study of p-type In1-xMnxAs films, with Mn composition x ranging from 0% to 2.5%, grown on GaAs by low-temperature molecular-beam epitaxy. Pulsed magnetic fields up to 500 T were used to make cyclotron resonance observable in these low-mobility samples. The cle…
Using off-lattice noise reduction it is possible to estimate the asymptotic properties of diffusion-limited aggregation clusters grown in three dimensions with greater accuracy than would otherwise be possible. The fractal dimension of these aggregates is found to be 2.50 +/- 0.01, in agreement with earlier studies, a…
Transport properties of itinerant electrons interacting with local spins are analyzed as function of the bandwidth, $W$, the exchange interaction, $J$, and the band filling, $n$, near the band edge. Numerical results have been obtained within the dynamical mean-field approximation and interpreted with the help of anal…
Localization driven by disorder has a strong influence on the conducting property of conducting polymer. A class of authors hold the opinion that disorder in the material is homogeneous and conducting polymer is disordered metal close to Anderson-Mott Metal-Insulator transition, while others treat the disorder as inho…
We report on quantitative calculations of the upper critical field $H_{c2}$ for clean type-II superconductors Nb, NbSe$_{2}$, and MgB$_{2}$ using Fermi surfaces from {\em ab initio} electronic structure calculations. The results for Nb and NbSe$_2$ excellently reproduce both temperature and directional dependences of…
Recently it has been predicted that a spin-polarized electrical current perpendicular-to-plane (CPP) directly flowing through a magnetic element can induce magnetization switching through spin-momentum transfer. In this letter, the first observation of current-induced magnetization switching (CIMS) in exchange-biased…
This article presents a new and efficient alternative to well established algorithms for molecular geometry optimization. The new approach exploits the approximate decoupling of molecular energetics in a curvilinear internal coordinate system, allowing separation of the 3N-dimensional optimization problem into an O(N)…
In the vapor−liquid−solid (VLS) growth of 1D nanostructures, the electronic structure of the substrate surface may critically affect the morphology of the grown nanowires/nanorods. In this paper, using a model system of the Sn-catalyzed growth of ZnO nanostructures on a single-crystal ZnO substrate, we demonstrate the…
In conjugated polymers the concept of spectroscopic units belonging to different spatial segments of the chain, which are responsible for the spectroscopic properties of the polymer, has been used to explain the spectral heterogeneity and the excitation migration by (Förster type) hopping transfer. In the present work…
The temporal evolution of fluorescence from isolated single-wall carbon nanotubes (SWNTs) has been investigated using optical Kerr gating. The fluorescence emission is found to decay on a time scale of 10 ps. This fast relaxation arises from nonradiative processes, the existence of which explains the relatively low ob…
Synthetic giant multiporphyrin arrays with well-defined architectures are reviewed in terms of artificial light-harvesting materials. Meso,meso-linked porphyrin arrays and multiporphyrin dendrimers have successfully mimicked the light-harvesting function of bacterial photosynthetic systems. We have also developed nove…
Differential pulse voltammetry (DPV) of TOPO-capped CdTe nanoparticles (NPs) in dichloromethane and a mixture of benzene and acetonitrile showed two anodic and one cathodic peaks of the NPs themselves and an additional anodic peak resulting from the oxidation of reduced NPs. The electrochemical band gap (∼2.1 eV) betw…
This paper describes electrochemical and spectroscopic properties of a well-characterized, synthetically accessible, 1.1 nm diam Au nanoparticle, Au(38)(PhC(2)S)(24), where PhC(2)S is phenylethylthiolate. Properties of other Au(38) nanoparticles made by exchanging the monolayer ligands with different thiolate ligands…