Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
We report the growth and characterization of crystalline, single-phase zinc blende MnS (i.e., β-MnS). The material was grown on ZnSe buffer layers on (100) GaAs substrates, using solid-source molecular beam epitaxy and a novel valved S cracker with deposition at low (∼110 °C) substrate temperatures. Characterization b…
Eu 3+ luminescence is of special importance as a spectral probe apart from its application in phosphor materials. This is possible for the reason that Eu 3+ has several structure-dependent transitions enabling one to gain insight about the site that it occupies in a given host. On this basis we have attempted to explo…
The possible occurrence of either a charge-density-wave or a Kohn anomaly is governed by the presence of Fermi-surface nesting and the subtle interaction of electrons and phonons. Recent experimental and theoretical investigations suggest such an effect for the hydrogen covered Mo and W(110) surfaces. Using density-fu…
A structure for an electro-optically controlled liquid crystal diffraction grating is proposed, which can dramatically simplify the fabrication process of liquid crystal optical gratings. The structure consists of two alternating stripes. Each stripe is a hybrid liquid crystal cell with adjacent stripes oriented perpe…
Free-standing powder of zinc sulphide quantum particles has been synthesized using a chemical route. X-ray diffraction analysis shows that the diameter of the particles is ∼21±2 Å which is smaller than the Bohr exciton diameter for zinc sulphide. UV absorption shows an excitonic peak centered at ∼300 nm corresponding…
The complete phase diagram of a ``colossal'' magnetoresistance material ( ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3}$) was obtained for the first time through magnetization and resistivity measurements over a broad range of temperatures and concentrations. Near $x\phantom{\rule{0ex}{0ex}}=\ph…
Formation of aluminosilicate minerals in marine sediments was proposed over 30 years ago as a potentially important control on the chemistry of the oceans. Until now, this reverse weathering process has been largely discounted because of insufficient direct evidence for its existence. Experiments with unaltered, anoxi…
A general class of exact solutions is presented for a time-evolving bubble in a two-dimensional slow viscous flow in the presence of surface tension. These solutions can describe a bubble in a linear shear flow as well as an expanding or contracting bubble in an otherwise quiescent flow. In the case of expanding bubbl…
In this paper we briefly review a model that describes the diffusion-controlled aggregation exhibited by particles as they are deposited on a surface. This model allows to understand many experiments of thin film deposition. In the first part, we describe the model, which incorporates deposition, particle and cluster…
Abstract The copolymers poly(propylene‐ co ‐ethylene) (PP/E) and poly(ethylene‐ co ‐vinyl acetate) (EVA) and blends of these were modified to develop an artificial matrix which promotes the growth of endothelial cells. Covalent immobilization of amino acids or sequences of adhesion glycoproteins should trigger the for…
Abstract Monsanto rheometric, dynamic mechanical, and solvent swelling studies indicate that functional groups of oxidized carbon black chemically react with carboxylated nitrile rubber (XNBR) when heated at high temperature for prolonged time. The reinforcing ability of the surface oxidized carbon black, measured by…
Abstract Coir fibers were chemically modified through alkali treatment, and crosslinking with formaldehyde, para ‐phenylene diamine, phthalic anhydride, and combined crosslinking‐cyanoethylation reactions in appropriate solvent and catalyst. The parent and chemically modified coir were characterized by FTIR spectra. T…
Abstract Photodegradation of incombustible polymer materials [high‐density (HD) and low‐density (LD) polyethylene (PE) containing 0.5 to 2.0 phr of decabromodiphenyl ether (DBDE) or tetrabromobisphenol A (TBA) as a flame retardant] were studied using an Okazaki Large Spectrograph (OLS). Samples were irradiated in air…
We report on optical and vibrational properties of porous silicon (por-Si) layers grown on p-type Si wafers by electroless etching technique. The results indicate a correlation between the photoluminescence (PL) intensity and the multihydride complexes (SiHn with n≥2). However, similar correlation was also found for m…
We report here the resistivity ( rho ) and the magnetoresistance (MR) of the ferromagnetic perovskite oxide system La 1-x Sr x CoO 3 (0.1<x<0.5) in a temperature range down to 4.2 K and magnetic fields up to 6 T. The MR is positive for x=0.5 and is negative for x<or=0.4. We find that while in the metallic samples (x>0…
Near-infrared to visible upconversion characteristics of Er3+ in CdX2-based halide glasses (X=Cl, Br, or I) has been investigated. When 4I9/2 state is pumped by 800 nm radiation from an AlGaAs laser diode, the upconverted green emissions (520–560 nm) of 2H11/2+4S3/2→I15/2 transition are clearly observed in all the gla…
We have measured the spectra of visible light emitted from the individual structures of porous Si (PS) below the probe tip of the scanning tunneling microscope (STM), and found that the peak energy of the emission spectrum shifts with the size of nanometer-scale structures on the PS surface. Samples with a PS layer ∼5…
The lattice stability and structure of delta -UZr 2 were studied by thermal analysis and high-resolution neutron diffraction techniques. The delta structure was confirmed to be the modified C32 (AlB 2 -type) structure as in the omega phase of Zr. The temperature dependence of the lattice parameters in the delta phase…
Transmission electron microscopy studies of the (1−x)Pb(Mg1/3Nb2/3)O3–(x)PbTiO3 [PMN-PT (1-x)/x] crystalline solution have been performed for x=0.1, 0.2, 0.35, and 0.60. Bright-field imaging has revealed a common sequence of domainlike states with increasing x. Normal micron-sized ferroelectric domains were found for…
Zinc sulphide nanoparticles in the size range ∼10–40 Å diameter have been synthesized using the aqueous chemical method. Scanning tunneling microscopy showed that particles are indeed nanosize particles. The size dependent band gap could be varied from a bulk value of 3.68 to 4.5 eV. X-ray diffraction indicated that n…