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。
Phosphane-functionalised carbosilane dendrimers 9, 10, 11, 12, 13, 19 and 20 have been synthesised, and their palladium complexes have been used as catalysts in the allylic substitution reaction. The catalytic sites at the periphery of the dendrimer support are readily accessible to the substrate, which is reflected −…
Dielectric permittivities, polarization--electric-field hysteresis loops, and domain structures have been measured as a function of temperature in relaxor-based ferroelectric single crystals $({\mathrm{PbMg}}_{1/3}{\mathrm{Nb}}_{2/3}{\mathrm{O}}_{3}{)}_{0.68}({\mathrm{PbTiO}}_{3}{)}_{0.32}$ (PMN-32%PT) for $〈110{〉}_{\…
Using empirical-potential and tight-binding models, we study the structure and stability of atomic-scale irradiation-induced defects on walls of carbon nanotubes. Since atomic vacancies are the most prolific but metastable defects which appear under low-dose, low-temperature ion irradiation, we model the temporal evol…
Vinyl-substituted chiral salens (salen=bis(salicylidene)ethylidenediamine) are used for attachment to Me3Si-hydrophobized silica gel (controlled-pore glass, CPG), carrying covalently bound mercaptopropyl ‘substituents', by AIBN-mediated radical addition of SH groups to styryl C=C bonds (Scheme 1, Table 1, and Figs. 1…
Pulsed laser ablation in an inert gas has been used to fabricate films containing silicon nanocrystals. We show that film microstructure is one of the main factors, determining long-term photoluminescence (PL) properties. Films with different porosity were found to exhibit PL signals with quite different peak energies…
Quasicrystals are metal alloys whose noncrystallographic symmetries challenge traditional methods of structure determination. We employ quantum-based total-energy calculations to predict the structure of a decagonal quasicrystal from first-principles considerations. Our Monte Carlo simulations take as input the knowle…
The complete experimental IR spectra and vibrational analysis of the title complex Co(mnt) (dmbpy) were reported in this paper. The results show that the complex molecule has a planar geometry belonging to point groupC 2v and ground electronic state with spin quartet. A new method for analyzing vibrational spectra of…
Scanning electron microscopy has shown etching of a porous silicon layer in an HF solution to be irregular. The intensity of porous silicon photoluminescence significantly decreases during gradual etching off, and its peak initially shifts to shorter and then to longer wavelengths. Under red-light pulse excitation, ph…
Gallogermanate glasses are the subject of intense study as a result of their unique combination of physical and optical properties, including transmission from 0.4 to beyond 5.0 microm. These glasses can be easily made into large optics with high-index homogeneity for numerous U.S. Department of Defense and commercial…
Thermodegradative investigations of two classes of multi-block copolymers containing poly(D,L-lactic-glycolic acid) (PLGA) and either poly(ethylene glycol) (PEG) or poly(ϵ-caprolactone) diol-terminated (PCDT) segments were performed. In particular, the influence of the type and length of the segments as well as of the…
Effects of a variety of water chemistry conditions on the theoretical understanding and development of an electrochemical corrosion potential (ECP) prediction model to calculate the ECP of structural materials in boiling water reactors (BWR) are described. In particular, the effects of dissolved oxygen (O2), hydrogen…
Abstract— Various nematic LC modes are reviewed and compared in terms optical throughput, driving voltage, response time, contrast ratio, and spectral responses for LCoS applications. The effects of fringe‐field‐induced disclination on display performance and the mechanism of slow response of the disclination line bet…
In this work we report the synthesis and structural characterization of the elpasolite Cs 2 NaTbCl 6 , belonging to the space group Fm3m. The synthesis is by solid state reaction, in controlled atmosphere. By means of thermal analysis (DTA/TGA), the best crystallization temperatures were obtained: 772.2 °C for 2 hours…
The star μ Orionis is a spectroscopic visual quadruple system in which each visual component is a short-period spectroscopic binary. The visual orbit has a period of 18.644 yr, a high eccentricity of 0.7426, and a high inclination of 96 2. The visual primary consists of an Am star and probably a G or early K dwarf tha…
Recently, no-load losses P and noise n of transformer cores have been reduced by replacing the former single-step-lap (SSL) joints by multistep-lap (MSL) joints. On the other hand, the application of MSL in model cores was found not only to decrease P and n, but in some cases they increase. The aim of this paper is th…
Abstract The natural aging of rigid poly(vinyl chloride) (PVC) used in building and construction areas has been studied. Bars of PVC exposed in Algiers, where the concentrations of atmospheric pollutants (NO x , O 3 , hydrocarbons) are known, show a small drop in strain at break and stress at break, whereas hardness r…
The present paper reports a comparative analysis of sigma 3 (in the coincidence site lattice notation) grain boundary types, in two grain boundary engineered brass specimens, by use of electron backscatter diffraction (EBSD) data coupled to the measurement of boundary traces in a single section. Although most of the d…
Czochralski grown (Sr 0.50 Ba 0.50 )Nb 2 O 6 single crystals have been studied by the method of precision X-ray diffraction analysis. The structural characteristics of (Sr x Ba 1 − x )Nb 2 O 6 compounds with x = 0.33, 0.50, 0.61, and 0.75 were analyzed. The distributions of the Sr and Ba atoms over the crystallographi…
ZnGa 2 Te 4 was found to crystallize in a defect tetrahedral structure with possible space group I 4 (82) with Z =2. Complete X-ray powder diffraction data were obtained and the unit cell parameters a and c and X-ray density were calculated. These were a =0.5930(1) nm, c =1.1859(3) nm, and D x =5.7×10 3 kg/m 3 .
In order to develop a reactor design model for the secondary reformer in the industrial ammonia plant, the effectiveness factor and convection heat transfer coefficient between gas and catalyst surface have been studied. The temperature and composition of inlet gas to the catalyst bed are predicted using the kinetic e…