Materials Literature
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Abstract The interpenetrating network matrices of epoxy and cyanate ester was made using epoxy resin and three different cyanate ester monomers namely 1,1‐bis(3‐methyl‐4‐cyanatophenyl) cyclohexane, bisphenol dicyanate and 1,3‐dicyanatobenzene and cured by using diaminodiphenylmethane. Epoxy modified with 4, 8 and 12%…
A series of cyano-bridged Ni(II)-Cr(I/III) complexes have been synthesized by the reactions of hexaazacyclic Ni(II) complexes with [Cr(CN)(6)](3-) or [Cr(CN)(5)(NO)](3-). Using the tetravalent Ni(II) complex [Ni(H(2)L(2))](4+) (L(2) = 3,10-bis(2-aminoethyl)-1,3,6,8,10,12-hexaazacyclotetradecane), one-dimensional chain…
The number and nature of silanol groups could be estimated in mesoporous silica prepared with cetyltrimethylammonium bromide (CTMBr) in acidic medium to obtain a material appropriate as a stationary chromatographic phase, using thermogravimetric analysis (TGA) and diffuse reflectance infrared spectroscopy (DRIFT). The…
A novel method for the production of homogeneous samples of hollow carbon nanospheres is reported from cellulose, an inexpensive and renewable precursor. The nanospheres are of diameter 50 nm, graphitic wall thickness 5-10 nm, and can easily be produced in several hundred milligram batches. The nanospheres are derived…
First-principles local-density approximation calculations of the piezoelectric response of $\mathrm{Pb}({\mathrm{Zr}}_{0.5}{\mathrm{Ti}}_{0.5}){\mathrm{O}}_{3}$ (PZT 50/50) are presented for tetragonal and monoclinic phases. We use the linearized augmented plane wave with the local orbital extension method and [001]1:…
A comprehensive, structural and functional, in silico analysis of the medium-chain dehydrogenase/reductase (MDR) superfamily, including 583 proteins, was carried out by use of extensive database mining and the blastp program in an iterative manner to identify all known members of the superfamily. Based on phylogenetic…
The chemisorption of NO 2 on carbon nanotubes is studied by modeling the interaction between NO 2 and N 2 O 4 with an infinitely long (8,0) single-walled carbon nanotube, using planewave/pseudopotential-based density functional theory (DFT). In sharp contrast to the case of graphite, for which NO 2 adsorption is physi…
We report an x-ray diffraction (XRD) analysis of the structural transformation from single-wall carbon nanotubes (SWNTs) to double-wall carbon nanotubes (DWNTs) via ${\mathrm{C}}_{60}$-encapsulating SWNTs $({\mathrm{C}}_{60}$ peapods). It was shown that the bundle structure of the starting SWNTs retains on this proces…
A tetraphenylporphyrin (1b) bearing amide groups at the 3,5-positions of the meso-phenyl groups is assembled into a two-dimensional sheetlike structure and acts as an organogelator. When [60]fullerene was added, the sheetlike structure was dramatically changed into a one-dimensional fibrous structure, and both the gel…
Local structure of the Fe-doped La$_{1-x}$Ca$_{x}$MnO$_{3}$ (x=0.00-1.00) compounds has been investigated by means of Mössbauer spectroscopy. $^{57}$Fe Mössbauer spectra provide a direct evidence of Jahn-Teller distortion in these manganites. On the basis of Mössbauer results, the Jahn-Teller coupling was estimated. I…
We present a systematic analysis of point-contact Andreev reflection (PCAR) spectra for ferromagnetic materials, using both modeling and experimental data. We consider the relationship between ballistic and diffusive transport, the effect of different transport regimes on spin polarization measurements, and the import…
An analytic representation of the short-range repulsion energy in ionic systems is described that allows for the fact that ions may change their size and shape depending on their environment. This function is extremely efficient to evaluate relative to previous methods of modeling the same physical effects. Using a we…
Our study presents experimental measurements of the contact and longitudinal voltage drops in Hall bars, as a function of the current amplitude. We are interested in the heating phenomenon which takes place before the breakdown of the quantum Hall effect, i.e. the pre-breakdown regime. Two types of samples has been in…
The h_u hole spectral intensity for C60 -> C60+ molecular photoemission is calculated at finite temperature by a parameter-free Lanczos diagonalization of the electron-vibration Hamiltonian, including the full 8 H_g, 6 G_g, and 2 A_g mode couplings. The computed spectrum at 800 K is in striking agreement with gas-phas…
We present detailed first-principles calculations for the normal state electronic properties of the high T$_C$ superconductor Bi$_2$Sr$_2$CaCu$_2$O$_8$, by means of the linearized augmented plane wave (LAPW) method within the framework of density functional theory (DFT). As a first step, the body centered tetragonal (…
We have fabricated carbon-nanotube (CN) field-effect transistors with multiple, individually addressable gate segments. The devices exhibit markedly different transistor characteristics when switched using gate segments controlling the device interior versus those near the source and drain. We ascribe this difference…
Many of the outstanding properties in oxides are related to materials with an intrinsic nanoscaled local structure, where the different regions are characterized by competing chemical, structural, and/or physical properties. One of the major challenges in the analysis of the nanoscaled oxides is experimental access to…
We have performed ab initio calculations within the density-functional theory for Ga_{1-x}Mn_xAs diluted semiconductors. Total energy results unambiguously show that a quasi-localized down-spin hole, with strong p-like character, surrounds the fully polarized Mn up-spin d^5-electrons. Calculations indicate that the ho…
We present high resolution two-photon excitation microscopy studies combining two-photon fluorescence (TPF) and second harmonic generation (SHG) in order to probe orientational distributions of molecular ensembles at room temperature. A detailed polarization analysis of TPF and SHG signals is used in order to unravel…
The Fifth Edition of Principles of Polymer Systems has been completely revised and updated. The chemical engineering perspective has been retained and strengthened, and the broad applications of polymers in chemistry and materials science have been addressed. The theoretical basis for various topics has been deepened…