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 report the first direct observation of the ultrafast electronic relaxation and coherent vibrational oscillation of strongly interacting gold nanoparticle aggregates measured by femtosecond laser spectroscopy. The electronic relaxation, reflected as a fast decay component with a time constant of 1.5-2.5 ps, becomes…
Abstract A series of six polyurethanes were prepared to study the effect of silicon chain extender structure on properties and morphology of siloxane–polyurethanes. Polyurethanes were prepared by a two‐step bulk polymerization without a catalyst. The soft segment of the polyurethanes was based on an 80:20 (w/w) mixtur…
Abstract Polymer microspheres are obtained by the dropwise addition of a precipitant, containing a polymeric stabilizer, into a polymer solution, containing a polymeric stabilizer. The polymer and stabilizer concentrations, the stirring speed, and the precipitation temperature determine the size and size uniformity of…
Many-body levels of optically excited and multiply charged InAs nanocrystals are studied with the semiempirical tight-binding model. Single-particle levels of unstrained spherical InAs nanocrystals are described by the ${\mathrm{sp}}^{3}{d}^{5}{s}^{*}$ nearest-neighbor tight-binding model including spin-orbit coupling…
The electrochemical properties of individual multiwall carbon nanotubes (MWNTs) coated with an amorphous carbon layer are reported. MWNTs were etched at potentials more positive than 1.7 V vs. Ag/AgCl (3 M NaCl) in an aqueous 0.1 M KCl electrolyte solution. The logarithm of etching rate was proportional to the applied…
Abstract The mechanical and dynamic mechanical properties of thermoplastic polyurethane (TPU) elastomers reinforced with two types of aramid short fibers, m ‐aramid (Teijin‐Conex) and copoly( p ‐aramid) (Technora), were investigated in this study with respect to the fiber loading. In general, both types of composites…
The rate of addition of the internal phase influences the catastrophic inversion of emulsions in the direction of change from abnormal to normal morphology. At a low addition rate, the inversion takes place after a small amount of the internal phase is added, and it happens through the occurrence of multiple emulsion…
The stirring intensity has a complex effect on the catastrophic inversion of emulsions in the direction of change from abnormal to normal morphology. At both low and high stirring energy, the inversion takes place early, after a low amount of the internal phase is added and through the occurrence of a multiple emulsio…
The adsorption properties of various water-soluble aromatic molecules (p-nitrophenol, p-nitroaniline, m-nitrophenol, p-chlorophenol and phenol), with CD-HMS, a new class of cyclodextrin-containing materials with uniform framework mesoporosity, has been investigated. The adsorption isotherms, uptake kinetics and distri…
Alternating electrostatic deposition of poly(amic acid) salts and poly (allylamine hydrochloride) (PAH) followed by heat-induced imidization yields ultrathin, gas-selective polyimide membranes on porous alumina supports. These membranes are appealing because of the stability and selectivity of polyimides and the fact…
The feasibility of ultrasound-induced in situ radical formation in liquid carbon dioxide was demonstrated. The required threshold pressure for cavitation could be exceeded at a relatively low acoustic intensity, as the high vapor pressure of CO2 counteracts the hydrostatic pressure. With the use of a dynamic bubble mo…
Polymer/carbon nanotube films have been formed by the alternate adsorption of the polyelectrolyte poly(diallyldimethylammonium chloride) and single walled carbon nanotubes (SWNT) onto substrates. Atomic force and scanning electron microscopies indicated that the adsorbed SWNTs were mostly in the form of 5−10 nm bundle…
To help understand and predict nanotube interactions, the electrostatic potentials on both the outer and the inner surfaces of 10 single-walled model systems have been computed at the Hartree−Fock STO-5G//STO-3G level. All structures were optimized computationally. Both carbon and boron/nitrogen tubes were studied, in…
Copper thiocyanate compounds with three different oxidation states, Cu(I)(admtrz)SCN (1), [Cu(I)(2)Cu(II)(admtrz)(6)(SCN)(2)](ClO(4))(2) (2), and [Cu(II)(3)(admtrz)(4)(SCN)(3)(mu(3)-OH)(H(2)O)](ClO(4))(2).H(2)O (3), have been synthesized and characterized (admtrz = 4-amino-3,5-dimethyl-1,2,4-triazole). Compounds 1 and…
Magnetic relaxation in molecular magnets under a sweeping field is studied by taking into account local stray fields. It is found that the randomness of local stray field leads to a distribution of the relaxation rate which subsequently makes the relaxation deviate from the exponential law as predicted by the Landau-Z…
Spatially resolved measurements of quasi-ballistic precessional magnetic switching in a microstructure are presented. Crossing current wires allow detailed study of the precessional switching induced by coincident longitudinal and transverse magnetic field pulses. Though the response is initially spatially uniform, de…
Band structure and optical properties of defect- Chalcopyrite type semiconductor ZnIn$_2$Te$_4$ have been studied by TB-LMTO first principle technique. The optical absorption calculation suggest that ZnIn$_2$Te$_4$ is a direct-gap semiconductor having a band gap of 1.40 eV., which confirms the experimentally measured…
Coaxial Zn/ZnO nanocables and ZnO nanotubes have been fabricated via a thermal reduction route using ZnS powder as the source material. The samples were characterized using X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectrometry. The as-synthes…
Abstract The French company Snecma Moteurs is a leading producer of high‐performance composites for operation under high mechanical stress and at high temperature, such as in jet engines, aircraft brake disks, or even rocket propulsion systems. The author presents the different families and generations of carbon‐carbo…
General aspects enzymes as proteins enzymes in foods (endogenous and exogenous) immobilized enzymes and their applications enzymes in food analysis mechanisms of action groups of enzymes and specific enzymes utilization in foods reaction(s)catalyzed classification according to enzyme committee nomenclature properties…