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 stability of metallic clusters of sodium (Na) in the octahedral cages of Na-doped fullerites Na6C60 and Na11C60 is discussed within a Thomas-Fermi model. It is shown that the tetrahedral Na4-cluster in Na6C60 has an electric charge of cca. +2.7 (in electron charge units), while the body-centered cubic Na9-cluster…
The resonance enhanced multiphoton ionization spectrum of the free radical SnF has been recorded using excitation wavelengths in the range 540 to 360 nm. The previously documented C 2Δ, D, E 2Π, and F 2Σ+ states and two hitherto unidentified excited states, the H and I 2Φ states, were all observed as two-photon resona…
A parameterized tight-binding model is applied to calculate the equilibrium structures, energies, band gaps and elastic properties of graphitic nanotubes with various helicities and radii. The structures, energies and band gaps for the tubes of large radii are in agreement with more accurate calculations. The elastic…
The adsorption of a single polymer chain onto a solid surface is investigated by molecular dynamics simulations. The chain is composed of mass points interacting via a truncated Lennard-Jones potential, i.e., the excluded volume interaction is taken into account, and grafted to the surface with one end. The average ad…
We present the theory of the analytical calculation of the SCF dipole polarizability and hyperpolarizabilities for molecular solutes described within the framework of the polarization continuum model. The formulation refers to a cavity with an accurately modeled molecular shape. Calculations of the components of the α…
The crystallization and transition temperatures of poly(ethylene terephthalate) (PET) in blends with polycarbonate (PC) is considered using thermal analysis. Additives typically used in commercial polyester blends, transesterification inhibitor and antioxidant, are found to enhance the crystallization rate of PET. Dif…
The so-termed starburst dendritic polyesters differ from classical polymers by their structural symmetry, high degree of branching, and high density of terminal functionality. The divergent synthesis of a series of polydisperse dendritic polyesters based upon pentaerythritol and 1,2,4-benzenetricarboxylic anhydride, m…
A very convenient synthetic method is described for the known cyclic aryloxyphosphazenes [N3P3(OC6H4-R)6] (R = Br, CN, CHO, COCH3, COC6H5, and NO2). The method is based on the direct reaction of [N3P3Cl6] with six equivalents of the para-substituted phenols HOC6H4-R and K2CO3 in refluxing acetone and is characterized…
Differential scanning calorimetry (DSC) and thermogravimetric analysis measurements were used to study the influence of the acidic comonomers acrylic acid, methacrylic acid, and itaconic acid on the exothermic reactions occurring during the heat treatment of acrylonitrile copolymers under air atmosphere. The presence…
Equilibrium and non-equilibrium molecular-dynamics simulations are performed to determine the structure, mechanical properties, and thermal conductivity of amorphous silicon nitride under uniform dilation. For mass densities below ρ = 2.6 g/cc, we observe a significant growth of pores. Near 2.0 g/cc the average pore v…
Using first-principles calculations, the phonon frequencies at the Γ-point and the dielectric tensor are determined and analysed for the cubic and rhombohedral phases of BaTiO 3 . The dipole-dipole interaction is then separated à la Cochran from the remaining short-range forces, in order to investigate their respectiv…
Reactions of aminosilanetriols RN(SiMe 3 )(Si(OH) 3 ) (R = 2,6-Me 2 C 6 H 3 ( 1a ), 2,6- i -Pr 2 C 6 H 3 ( 1b ), 2,4,6-Me 3 C 6 H 2 ( 1c )) with titanium orthoesters Ti(OR‘) 4 (R‘ = Et, i -Pr) in hexane at room temperature afford new cubic titanasiloxanes [RN(SiMe 3 )SiO 3 Ti(OR‘)] 4 ( 2a − f ) in nearly quantitative…
The absolute chirality of potassium dithionate, , , trigonal, space group P321, a = 9.782(1) Å, c = 6.298(2) Å, , Z = 3, R = 0.024, wR = 0.031 for 2586 unique observed reflections, has been determined at room temperature through a combination of single-crystal x-ray diffraction, including anomalous scattering, and opt…
Thin films made by annealing Cu(500 nm)/Al(7 nm)/SiO2/Si are investigated using Rutherford backscattering and resistivity measurements. Annealing these films in a low pressure of oxygen results in the formation of a thin surface layer of hole-free aluminum oxide which protects the underlying copper from oxidation. Eve…
During furnace N2O-based silicon oxynitride growth, the total concentration of NOx species varies strongly with the flow rate of N2O. At low flow rates the N2O decomposes at least partially in the cooler region of the furnace near the gas inlet. This results in lower than expected NOx (x=1,2) concentrations in the oxi…
Lanthanum modified lead zirconate titanate (PLZT) ceramics with a Zr/Ti ratio of 85/15 were investigated as a function of La content by dielectric spectroscopy, Sawyer–Tower polarization techniques, and electron microscopy. Tweedlike structures were found to evolve from normal μm-sized ferroelectric domains with incre…
Chiral conductivities of nanotubes are examined within the framework of the Boltzmann transport equation. Electron transport along a chiral trajectory is decomposed into current components along the tubule axis and its circumference. Within a constant relaxation time approximation, these components are derived from th…
The thermal stability in vacuum of amorphous tetrahedrally coordinated carbon (a-tC) films grown on Si has been assessed by in situ Raman spectroscopy. Films were grown in vacuum on room-temperature substrates using laser fluences of 12, 22, and 45 J/cm2 and in a background gas of either hydrogen or nitrogen using a l…
We report the realization of a bright and stable electroluminescent Schottky diode based on aluminum-porous silicon junction. White light, visible in normal daylight, is emitted when a reverse bias is applied to the device, promoting the junction breakdown. The device has a fast (100 ns) rise time of the light emissio…
Core-level photoabsorption has been used to determine the sp2 and sp3 bonding content of nanocrystalline diamond thin films grown using C60 or CH4 precursors. The C(1s) absorption spectra show clear bulk diamond excitonic and sp3 features with little evidence of sp2 bonding, while the Raman spectra measured from these…