Materials Literature
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The progresses obtained in both catalyst performances and process technologies have made the continuous expansion of PP properties possible. The discovery of MgCl2-supported catalysts and the development of their controlled spherical morphology produced a real revolution in the catalytic-system performances. A series…
We have shown in the present article, starting from the high capacity PP′s on the market, the development of long-chain branched PP which means melt strength PP. As a basis, the radical mechanism were used to synthesize long-chain branched PP. Most known is the process at low temperature by using electron-beam-irradia…
Boron carbide-filled (BN) x C y nanotubes with outer layers of pure carbon and inner layers of pure boron nitride (BN) have been synthesized for the first time in high yield by using pure carbon nanotubes (CNTs) as templates. The (BN) x C y nanotubes form by capillary filling of boron oxide vapor condensed into the in…
We report an investigation of how much protein structural information could be obtained using a site-directed fluorescence labeling (SDFL) strategy. In our experiments, we used 21 consecutive single-cysteine substitution mutants in T4 lysozyme (residues T115-K135), located in a helix-turn-helix motif. The mutants were…
The preparation and characterization of two crystalline forms of [Fe(TMP)(5-MeHIm) 2 ]ClO 4 with distinctly different molecular structures are reported. Crystal structure analysis shows that paral -[Fe(TMP)(5-MeHIm) 2 ]ClO 4 has the axial imidazole ligands arranged in a relative parallel orientation (over a slightly S…
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…