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。
Synthesis of carbon nanotubes by chemical vapor deposition over patterned catalyst arrays leads to nanotubes grown from specific sites on surfaces. The growth directions of the nanotubes can be controlled by van der Waals self-assembly forces and applied electric fields. The patterned growth approach is feasible with…
The synthesis of the fluorine-substituted stannasiloxane complex cyclo-Ph 2 Si(OSnt-Bu 2 ) 2 O· t -Bu 2 SnF 2 ( 7 ) is reported, and its molecular structure has been determined by single-crystal X-ray diffraction analysis.
The synthesis of the fluorine-substituted stannasiloxane complex cyclo-Ph2Si(OSnt-Bu2)2O·t-Bu2SnF2 (7) is reported, and its molecular structure has been determined by single-crystal X-ray diffraction analysis.
Solutions of 4-methylphenylurethane of cellulose in N -vinyl pyrrolidinone have been investigated, and a cholesteric mesophase was found above a concentration of 35 wt % of polymer. The selective reflection of light from the cholesteric solutions lies in the visible region of the spectrum and moves from blue toward re…
We evaluate, by means of variational calculations, the bound state energy ${E}_{B}$ of a pair of charges located on the surface of a cylinder, interacting via Coulomb potential $\ensuremath{-}{e}^{2}/r.$ The trial wave function involves three variational parameters. ${E}_{B}$ is obtained as a function of the reduced c…
[structure: see text] An o-allenyl-p-methoxyphenol intermediate (Int) was for the first time proved to be involved in the photochromic reaction of 2,2-di(4-fluorophenyl)-6-methoxy-2H-1-chromene (FC). Transoid-cis (TC) and transoid-trans (TT) photomerocyanines and the intermediate Int are generated by UV irradiation of…
A formalism based on Yeh’s 4 × 4 matrix algebra is developed to model reflectance and transmittance spectra of randomly oriented polycrystalline materials (sintered ceramics or glass ceramics) with arbitrary crystal symmetry provided that the crystallites are larger than the resolution limit of light. It may be applic…
The CO 2 reforming of methane was studied over Pt supported on Al 2 O 3, ZrO 2, and x % ZrO 2 /Al 2 O 3 (1 ≤ x ≤ 20 wt %). The Pt/Al 2 O 3 deactivated very quickly during 20 h onstream at 1073 K and a CH 4 /CO 2 ratio of 1:1, while the catalysts with a ZrO 2 content above 5 wt % presented improved stability during 60…
The photoinduced electron transfer (ET) in five structurally different phytochlorin-fullerene dyads was studied in polar and nonpolar solvents using femtosecond fluorescence up-conversion and pump−probe transient-absorption techniques. Small changes in the structures of the dyads result in considerable changes in the…
We report experimental evidence for the stress-induced tetragonal symmetry of the paraelectric phase in heteroepitaxial $({\mathrm{Ba}}_{0.7}{\mathrm{Sr}}_{0.3}){\mathrm{TiO}}_{3}$ thin film deposited on the (001)MgO substrate. Our Raman and x-ray-diffraction data evidently show that symmetry of the paraelectric phase…
The synthesis and mesomorphic properties of a new series of five-ring esters composed of banana-shaped molecules are reported. The homologues containing n-dodecyloxy, n-tetradecyloxy and n-hexadecyloxy terminal chains exhibit a smectic phase while that with an n-octadecyloxy chain shows a two-dimensional structure. Th…
The influence of γ-irradiation on the positron annihilation lifetime spectra in chalcogenide vitreous semiconductors of As-Ge-S system has been analysed. The correlations between lifetime data, structural features and chemical compositions of glasses have been discussed. The observed lifetime components are connected…
Clinically available synthetic ePTFE vascular grafts frequently fail when used for small-diameter arterial substitution. The lower long-term patency of ePTFE grafts is due mainly to thrombogenicity and poor healing. We developed a new small-diameter (1.5-mm) ePTFE vascular prosthesis coated with polyamino-acid urethan…
Abstract The use of biodegradable polymer films for mulching is a topic of great interest both from the environmental point of view and for the intrinsic properties that the above films, when appropriately designed, might have. In the present article we report on a synthetic approach that, starting from existing biode…
Abstract In this article, we discuss the radiation effects of high‐density polyethylene (HDPE)/ethylene–vinyl acetate (EVA) copolymer blends. In comparison with the low‐density polyethylene/EVA blends, the EVA content in the HDPE/EVA blends had a lower enhancement effect on radiation crosslinking by γ‐ray irradiation…
Neutron powder diffraction measurements on ${\mathrm{Ca}}_{2}{\mathrm{FeReO}}_{6}$ reveal that this double perovskite orders ferrimagnetically and shows anomalous lattice parameter behavior below ${T}_{C}=521\mathrm{K}.$ Below $\ensuremath{\sim}300\mathrm{K}$ and $\ensuremath{\sim}160\mathrm{K}$ we observe that the hi…
Recent experiments have identified three-layer and four-layer distorted helical structures in the smectic liquid-crystal phases Sm C*(FI1) and Sm C*(FI2), respectively. However, no theories have explained the existence of all these phases. A discrete phenomenological model of the free-energy is analyzed and found to p…
HiPco single-walled carbon nanotubes (HPNTs) containing Fe were purified by a one-step process with HCl-washing (D-method) and a two-step process with HCl-washing after air oxidation (GD-method). The HPNT samples before and after purification were characterized using the N 2 adsorption at 77 K, thermogravimetric analy…
The random discontinuous fiber composite has uniform properties in all directions. The wetlay process is an efficient method to manufacture random discontinuous thermoplastic preform sheets that can be molded into random composite plaques in the hot-press. Investigations were done on the molding parameters that includ…
Charge transport and magnetic properties of films of polyaniline (PAN) doped with 10-camphorsulfonic acid and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPSA) have been studied by conductivity, magnetic-susceptibility superconducting quantum interference device measurements, and 3-cm and 8-mm electron paramagnetic…