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。
The behavior of species in the gas phase and their effects on the etching characteristics of organic film with the lower dielectric constant (low-k) were investigated in 500 MHz ultrahigh frequency (UHF) plasma using N2/H2 and N2/NH3 gases. The absolute H and N radical densities and NH3 molecule density in etching pla…
Abstract The graft copolymerization of acrylonitrile (AN) onto Cassia tora gum (CTG) was carried out in an aqueous medium with a ceric ammonium nitrate (CAN)–nitric acid initiation system. The percentage grafting and percentage grafting efficiency were determined as functions of the concentrations of CAN, nitric acid,…
In this letter, we report the formation of bulk samples of silica-based glass containing Si nanocrystals (Si-ncs) by pyrolysis of a preceramic precursor. The starting precursor is a sol–gel-derived polysiloxane containing only Si–H groups which leads, after annealing in a controlled atmosphere in the range 1000–1200 °…
The title compound, a new polymorphic phase of iron diphosphate, was prepared by solid-state reaction. This compound crystallizes in the monoclinic space group P 2 1 / c with a = 4.4668(6) Å, b = 9.896(1) Å, c = 5.2077(7) Å, β = 97.516(2)°, V = 228.22(5) Å 3, and Z = 2. The structure is characterized by the arrangemen…
Tb 3+ -doped Lu2O3 sintered ceramics were prepared in vacuum and in air. It was shown that the vacuum-sintered disks are able to store energy when irradiated with 300-nm or shorter photons. A small part of the stored energy could be recovered with 980-nm light. A much more significant amount of the stored energy could…
A novel method is introduced to estimate surface coverage and the equation of state of insoluble surfactant on droplets, involving measurement of interfacial tension on a single parent drop and progressively subdivided generations of daughter drops. This has enabled quantitative decomposition of the dilution, tip-stre…
Amorphous diamond-like carbon films were irradiated with high-energy heavy ions like 1 GeV uranium or 340 MeV gold. The large energy deposition along the ion track leads to a transformation of the material from insulating diamond-like to conducting graphite-like carbon. The ion tracks form thin straight channels (nano…
Chirality of optically active liquid crystal molecules has become an important research topic and the subject of a number of theoretical and experimental studies. We present here the results of the application of a newly developed scaling method of a chiral index to a range of chiral molecules. Good agreement is found…
AlN layers grown on Al2O3 substrates by metalorganic chemical vapor desposition were implanted with high doses (3×1016 cm−2, 250 keV) of Co+, Cr+, or Mn+. Band-edge photoluminescence intensity at ∼6 eV was significantly reduced by the implant process and was not restored by 950 °C annealing. A peak was observed at 5.8…
We have studied crystallization in a system of sedimenting colloids in real space using fluorescence confocal microscopy. During sedimentation a gradient in particle concentration develops at the bottom of the sample container. The presence of the lower boundary wall induces layering in the liquid and, upon increasing…
Collagen model peptide (Pro-Pro-Gly)10 has a triple helical structure and undergoes a thermal transition to a single random coil structure. The transition temperature of the analogous model peptides depends largely on amino acid substitution. Substitution of Pro by 4-hydroxyproline (Hyp) or 4-fluoroproline (fPro) has…
A first-principle investigation of the effects of multiple Si=O bonds at the surface of silicon-based clusters with different sizes has been carried out. Total-energy pseudopotential calculations within density functional theory have been applied varying systematically the number of Si=O bonds at the clusters surface.…
Abstract The compatibility of natural rubber/ethylene‐propylene‐diene monomer (EPDM) blends with and without different compatibilizers was evaluated with viscosity measurements, differential scanning calorimetry, and scanning electron microscopy. The blends were modified with two methods. In the first method, high‐ene…
We report on the in-situ formation of ZnO nanobelts and metallic Zn nanobelts and nanodisks in a transmission electron microscope by electron-beam irradiation of single-crystalline polyhedral Zn nanoparticles, which were synthesized by evaporating ZnO powder mixed with graphite in a N 2 flowing carrying gas environmen…
The carbon nanofibers used in this work were derived from polyacrylonitrile/N,N-dimethyl formamide precursor solution using electrospinning and vacuum pyrolysis techniques. Their conductivity σ was measured at temperatures between 1.9 and 300 K and transverse magnetic field between −9 and 9 T. Zero magnetic field cond…
The linear absorption spectra, resonance Raman excitation profiles and depolarization dispersion curves, and hyper-Rayleigh scattering profiles are calculated for excitonically coupled homodimers of a model electron donor–acceptor “push–pull” conjugated chromophore as a function of dimer geometry. The vibronic eigenst…
Abstract Blends of the conducting polymer, polypyrrole (PPy), and in the insulating host polymers, polyvinyl acetate (PVAc), polystyrene (PS), and polyvinyl chloride (PVC) resin, have been prepared chemically. Threshold conductivities occur at about 5% for PPy in blends with host polymers. The characterizations of the…
We present computer simulations of long, thin, hard spherocylinders in a narrow planar slit. We observe a transition from the isotropic to a nematic phase with quasi-long-range orientational order upon increasing the density. This phase transition is intrinsically two-dimensional and of the Kosterlitz–Thouless type. T…
We present a structural and magnetic study of La0.7Ca0.3MnO3 epitaxial films (the thickness ranges from 2.4 to 80 nm) on SrTiO3. Their structure, as obtained by x-ray diffraction, is orthorhombic with a 45° rotated 2×2 square lattice, referred to the SrTiO3 substrate, in the film plane. The 2.4 nm film adopts a differ…
The phase behavior of mixtures of polyisobutylene (PIB), polyethylene (PE), and a symmetric polyethylene- block -head-to-head polypropylene copolymer (PE−PP) was studied by transmission electron microscopy (TEM) and small-angle neutron and light scattering. The thermodynamic interactions between PE/PP and PE/PIB are r…