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。
Unoccupied density of states (DOS) for the polar (0001) Zn, (000 ) O and non-polar (10 0) ZnO surfaces and for a MgO(001)-c(2 × 2) thin film were studied using total current spectroscopy (TCS). TC spectra of the ZnO surfaces reveal the Zn 4s-O 2p band (6.2 eV) and two DOS maxima in the Zn 4p-O 2p band which exhibited…
Recent progress in transition metal catalyzed propylene polymerization based upon single-site catalysts and melt compounding of polypropylene is stimulating the development of novel polypropylene materials with unconventional property combinations such as improved low temperature toughness, low haze, elasticity, and i…
We present a microscopic theory of ferroelectric phase transitions and off-centre displacements in perovskites. We show that the inclusion of strong intraband electron-phonon interaction (i.e. the existence of small polarons) into the framework of the interband theory of displacive-like ferroelectrics leads to local s…
Peptide segments in a protein, which can include an active site of interest or be a series of parts constituting the entire structure, are now selectively observed by nuclear magnetic resonance (NMR) spectroscopy using samples prepared by the intein-mediated ligation method. Two separate inteins were used to ligate NM…
Interatomic potentials are determined in the framework of a shell model used to simulate the structural instabilities, dynamical properties, and phase transition sequence of BaTiO 3 . The model is developed from first-principles calculations by mapping the potential energy surface for various ferroelectric distortions…
Reaction of [RhCl(NBD)] 2 with 2.0 equiv of triphos (triphos = bis(2-diphenylphosphinoethyl)phenylphosphine; NBD = bicyclo[2.2.1]hepta-2,5-diene) in THF solution at room temperature affords [Rh(NBD)(triphos)][Cl] ( 4a ), which was isolated as [Rh(NBD)(triphos)][SbF 6 ] ( 4b ) in 67% yield. Treatment of 4b with aqueous…
We use a high-statistic quantum Monte Carlo and Maximum Entropy regularization method to compute the dynamical energy correlation function (DECF) of the one-dimensional (1D) $S=1/2$ antiferromagnetic Heisenberg model at finite temperatures. We also present a finite temperature analytical ansatz for the DECF which is i…
Processes on different length scales affect the dynamics of chain molecules. In this work, we focus on structures on the scale of a monomer and investigate polyolefins, i.e. hydrocarbon chains with different small scale architectures. We present an exact enumeration scheme for the simulation of interactions and relati…
Numerous experimental indications suggest that the Hume-Rothery mechanism plays an important role in stabilizing quasicrystalline and amorphous phases. However, the exponential damping of the conventional Friedel oscillations at the relevant, elevated temperatures $T$ poses a severe challenge to the HR stabilization.…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTA Novel Octupolar Metal−Organic NLO Material Based on a Chiral 2D Coordination NetworkWenbin Lin, Zhiyong Wang, and Ling MaView Author Information Department of Chemistry, Brandeis University Waltham, Massachusetts 02454 Cite this: J. Am. Chem. Soc. 1999, 121, 48, 1124…
A new methacrylate with a tethered silacyclobutane moiety, 6-(methylcyclotrimethylenesilyl)hexyl methacrylate, has been synthesized. Radical polymerization (thermal) yielded a linear poly(methacrylate) without affecting the silicon-containing four-membered ring. Photoactivated ring-opening polymerization of the silacy…
We have performed a theoretical investigation of the optical properties of the molecule chromone, using multireference perturbation theory (CASPT2) and time-dependent density functional theory (DFT) methods. The structure of the molecule was optimized at the DFT level and at the level of complete active space self-con…
Ab initio molecular orbital calculations have been carried out for silicate, aluminosilicate, and aluminate clusters in order to study the NMR characteristics of oxygen sites that are possibly present in the structure of aluminosilicate glasses and melts. Of particular interest are the different types of bridging oxyg…
Kaolinite hydroxyl surfaces have been modified upon intercalation with cesium acetate under a range of conditions. Upon intercalation of both low- and high-defect kaolinites with cesium acetate at 25 °C, additional infrared hydroxyl stretching bands are observed at 3606 and at 3603 cm - 1 . New infrared hydroxyl defor…
A novel resonant method based on a tunnel-diode oscillator (TDO) is used to study the dynamic transverse susceptibility in a Fe nanoparticle system. The magnetic system consists of an aggregate of nanometer-size core (Au)-shell (Fe) structure, synthesized by reverse micelle methods. Static and dynamic magnetization me…
The magneto-impedance (MI) of glass-coated Fe-Ni-Cu microwires was investigated for longitudinal radio-frequency (RF) currents up to a frequency of 200 MHz using an RF lock-in amplifier method. The MI, defined as DZ/Z = [Z(H)-Z(H=0.3T)]/Z(H=0.3T), displays a peak structure (negative MI) at zero field for RF currents w…
Colloidal dispersions of rod-shaped gold particles are obtained by electrodeposition of gold in the nanopores of anodized alumina attached to a conductive support followed by dissolution of the alumina and release of the rods from the support. Coagulation is prevented by steric repulsion due to adsorption of poly(viny…
A software package has been developed for simulating and designing multipole systems containing electrostatic round lenses, electrostatic and magnetic quadrupole, hexapole and octopole lenses, and Wien filters. Using our SOFEM and 3D packages, the field functions and their derivatives of these optical elements can be…
We present for the first time a theory for the long-time wave number ( k -) dependent collective and self-diffusion coefficients D L ( k ,ϕ) and D S L ( k ,ϕ), respectively, of neutral colloidal suspensions at high volume fractions ϕ. This theory is based on the Smoluchowski equation with mean-field–like hydrodynamic…
A new technique for measuring the twist elastic constant (K22) using an in-plane electrode structure was investigated. The variation in the temperature dependence of K22 with respect to the molecular structure of fluorinated phenylbicyclohexane (PBC) compounds was investigated. The experimental cell has in-plane elect…