Materials Literature
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We revisit the expression for the conductance of a general nanostructure -- such as a quantum point contact -- as obtained from the linear response theory. We show that the conductance represents the strength of the Drude singularity in the conductivity $σ(k,k';iω\to 0)$. Using the equation of continuity for electric…
In order to provide a quantitatively accurate description of the band-gap variation with sizes in various II-VI semiconductor nanocrystals, we make use of the recently reported tight-binding parametrization of the corresponding bulk systems. Using the same tight-binding scheme and parameters, we calculate the electron…
This letter addresses the issue of surface softening versus stiffening during elastic deformation. Using a combination of molecular statics and ab initio calculations, we show that a solid surface can be either softer or stiffer elastically than the corresponding bulk. Whether a particular surface is softer or stiffer…
In this paper we have calculated electron transport coefficient in ballistic regime through a periodic dot sandwiched between uniform leads. We have calculated the Green's function (GF), density of states (Dos) and the coherent transmission coefficient (conductance) fully analytically. The quasi gap, bound states ener…
Mn-doped wurtzite GaN epilayers have been grown by nitrogen plasma-assisted molecular beam epitaxy. Correlated SIMS, structural and magnetic measurements show that the incorporation of Mn strongly depends on the conditions of the growth. Hysteresis loops which persist at high temperature do not appear to be correlated…
Novel poly(p-phenylenevinylene)s (PPVs) with a dendritic phenylazomethine (DPA) as a metal-collecting site were synthesized via the Heck reaction by filling the coordination site of DPA moiety via complexation with rare earth metal ions.
We present results of first-principles calculations of structural, magnetic, and electronic properties of small Fe clusters. It is shown that, while the lowest-energy isomers of Fe 3 and Fe 4 obtained in the framework of density functional theory within the generalized gradient approximation (GGA) are characterized by…
The structure of the polymeric substrate plays an important role in the nucleation of calcium carbonate crystals. In this study a synthetic water-soluble poly(acrylamide-co-2-acrylamido-2-methyl-1-propane sodium sufonate-co-n-vinyl pyrrolidone) was found to be a substrate favoring the nucleation of polymorphs of calci…
This work reports the results obtained on the synthesis of the Aurivillius oxide SrBi 4 Ti 4 O 15 as carried out by mechanochemically assisted methods. The effects of changing the milling media (vibrating and planetary mills) and the length of the mechanical treatment are discussed. The products obtained were characte…
The porosity and the available surface area of a lignocellulosic fiber can influence the accessibility and reactivity in derivatization and modification reactions because the porous cell-wall network determines the upper size limit for molecules that can penetrate and react with the interior of the wall. To obtain inf…
Abstract Gold nanoparticles deposited [by homogeneous deposition-precipitation (HDP) using urea] on Yb2O3 and other rare-earth oxides (viz. Sm2O3, Eu2O3, and Tb2O3) are novel highly active/selective and reusable catalysts for the selective epoxidation of styrene to styrene oxide by anhydrous or aqueous t-butyl hydrope…
Transmission electron microscopy and X-ray scattering have been used to characterize the microphase segregation of linear−dendritic diblock copolymers in the bulk state. The dendritic block copolymers consisted of a linear poly(ethylene oxide) (PEO) block of 2000 molecular weight attached covalently to a polyamidoamin…
Abstract A periodic ordered mesoporous organosilica containing uniform ethane groups in the pore walls was prepared using microwave heating to produce 1.5–2.5-μm uniform particles with spherical morphology.
Experimentally based lattice energies are calculated for the apatite family of double salts M(5)(PO(4))(3)X, where M is a divalent metal cation (Ca, Sr, Ba) and X is hydroxide or a halide. These values are also shown to be estimable, generally to within 4%, using the recently derived Glasser-Jenkins equation, U(POT) =…
The selective catalytic reduction (SCR) of N 2 O with CH 4 in the absence and presence of excess O 2 has been studied over ion-exchanged Fe−BEA catalyst by the combination of an activity test with in-situ infrared spectroscopy to understand the nature of the surface species involved in the SCR of N 2 O with CH 4 . Fro…
The Johari−Goldstein (JG) secondary relaxation, presumed to be universal, has never been seen in 1,4-polyisoprene (PI) by dielectric spectroscopy, despite very many measurements extending over the past half-century. By using a high-resolution capacitance bridge, we are able to show the existence of a secondary relaxat…
The thixotropic properties ofthermoreversible organogels composed ofN-3-hydroxypropyl dodecanamide and various apolar fluids have been investigated by X-ray scattering, light microscopy, and rheo-optics experiments. This revealed that gel formation occurs via a precipitation process. Depending upon the cooling rate, l…
A nearly-free-electron (NFE) model to describe STM spectroscopy of (111) metal surfaces with Kondo impurities is presented. Surface states are found to play an important role giving a larger contribution to the conductance in the case of Cu(111) and Au(111) than Ag(111) surfaces. This difference arises from the farthe…
Self-assembly of structurally tunned nearly monodispersed HgTe - ssDNA nanostars of average size 1.4 nm have been achieved by manipulating HgTe nanoparticles using single stranded (ss) DNA under galvanostatic condition. The nanostars are linked with one another by ssDNA of length 0.35 nm. Whereas, HgTe nanoparticles w…
The effect of organoclay platelets on morphologies of three blend compositions (80/20, 20/80, and 99.5/0.5 w/w) of nylon-6 (N6) and poly(ethylene- ran -propylene) rubber (EPR) has been studied by scanning and transmission electron micrographs. For the 80/20 (w/w) N6/ERP blend, the dispersed domain size ( D ) of EPR ph…