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。
We present a density functional theory study of water adsorption on metal surfaces. Prototype water structures including monomers, clusters, one-dimensional chains, and overlayers have been investigated in detail on a model system---a Pt(111) surface. The structure, energetics, and vibrational spectra are all obtained…
We demonstrate for the first time that impact ionization (II) (the inverse of Auger recombination) occurs with very high efficiency in semiconductor nanocrystals (NCs). Interband optical excitation of PbSe NCs at low pump intensities, for which less than one exciton is initially generated per NC on average, results in…
A re-parameterization of the standard TIP4P water model for use with Ewald techniques is introduced, providing an overall global improvement in water properties relative to several popular nonpolarizable and polarizable water potentials. Using high precision simulations, and careful application of standard analytical…
Abstract The nonisothermal crystallization, melting behavior, and morphology of blends of polypropylene (PP) and a metallocene‐catalyzed polyethylene (mPE) elastomer were studied with differential scanning calorimetry, scanning electron microscopy, polarized optical microscopy, and X‐ray diffraction. The results showe…
Recent studies have shown that elongation factors extracted from archaea/eukarya and from eubacteria exhibit different structural and functional properties. Along this line, it has been demonstrated that, in contrast to EF-Tu, Sulfolobus solfataricus EF-1alpha in complex with GDP (SsEF-1alpha.GDP) does not bind Mg(2+)…
Abstract A model is suggested for the split of dislocated pipes at the front a growing crystal. Within the model, the pipe split occurs through the generation of a dislocation semi‐loop at the pipe and crystal surfaces and its subsequent expansion into the crystal interior. The strain energy of such a dislocation semi…
We show that reaction of aqueous cadmium cations with phosphotungstate Keggin anions leads to the growth of highly dense and crystalline cadmium phosphotungstate colloidal particles with needlelike morphology of submicron dimensions. Further treatment of the crystalline cadmium phosphotungstate colloidal particles wit…
To perform the catalytic conversion of natural gas to synthesis gas, a compact radial reactor supplied with a structured porous metal catalyst has been designed. The reactor was tested at normal pressure using natural gas and air. The reactor can operate without preheating of the inlet gas mixture. A novel structured…
Abstract Clays belong to an economic class of fillers, which are used extensively in rubbers and plastics. Being nonreinforcing in nature, there are limitations upon its use. If the properties of filler are modified, it will get a higher value as a filler. To achieve this modification of surface properties is one of t…
Se estudió la comunidad de macroinvertebrados acuáticos asociados a los depósitos de agua de Tillandsia turneri (Bromeliaceae) en un bosque alto andino de Cundinamarca, Colombia. Se recolectaron 37 plantas y se les determinó algunas variables morfológicas y fisicoquímicas. Se encontraron 28 morfoespecies de macro inve…
In this study, an end-functionalized graft copolymer, thiol-terminated poly(2-hydroxyethyl methacrylate- g -ethylene glycol) or SH-poly(HEMA- g -EG), was synthesized by the atom transfer radical polymerization (ATRP) method and then characterized by 1 H nuclear magnetic resonance (NMR), gel permeation chromatography (…
Bacillus megaterium can produce poly-beta-hydroxybutyrate (PHB) as carbon and energy storage materials. We now report that the phaQ gene, which is located upstream of the phasin-encoding phaP gene, codes for a new class of transcriptional regulator that negatively controls expression of both phaQ and phaP. A PhaQ bind…
In this article, we describe a facile and effective method for the modification of multiwall carbon nanotubes with molecular anchor molecules using supercritical fluids (SCFs). Through choice of deposition conditions, the degree of loading in these nanotube-anchor structures can be controlled to achieve sub-monolayer,…
Temperature-dependent dynamics of monolayer-protected Au and Ag nanoclusters and silver thiolates have been investigated with quasielastic neutron scattering. The simplest motion in these systems is the uniaxial rotation of the chain, which evolves slowly with temperature. While longer chain monolayers (above C 8 ) on…
Diffraction gratings of weak efficiency (≈2−3%) were inscribed on thin films of the azobenzene p(DR1M) homopolymer using orthogonal linear (+45°,+135°) polarizations of two coherent laser beams. After an erasure process using a single beam of circular polarization (“RCP”), the surface relief profiles measured from ato…
Abstract An inductively coupled pulsed‐plasma reactor was used to synthesize polyaniline thin films on several substrates positioned at various distances from the center of the radio frequency (RF) coil. The samples were characterized with Fourier transform infrared (FTIR), cyclic voltammetry, and microscopic techniqu…
Abstract The crosslinking of metallocene ethylene–octene copolymer was investigated. The crosslinked polymers were prepared using two different techniques, i.e., peroxide crosslinking and silane–water crosslinking. In the former, the crosslinking reaction was conducted in a twin‐screw extruder, in the presence of dicu…
The potentially tridentate macrocycle [2.1.1]-(2,6)-pyridinophane (L) enables the transient LPt(II)(CH(3))(+) to cleave the C-H bond of two molecules of C(6)F(5)H. The resulting product has two aryl groups on Pt but, in contrast to nonfluorinated analogue, varies in its location of the cleaved H, as is evident from th…
Molten Carbonate Fuel Cells (MCFC) operate at temperatures ranging from 600 to 700°C; high temperatures allow to obtain low internal losses with large benefits in terms of generated electric power. A new geometry for small sized MCFCs is proposed in this paper. Cell thermofluidodynamic performance has been analyzed th…
Abstract The devulcanization of sulfur‐cured unfilled butadiene rubber (BR) with a grooved‐barrel ultrasonic reactor under various processing conditions was carried out. The experiments indicated that BR had a narrow devulcanization window. Outside this window, significant degradation or no devulcanization occurred. G…