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 crystal and molecular structure of pyridinium fluorochromate has been determined at 293, 240, and 150 K by x-ray diffraction. All three phases are orthorhombic with the following sequence of space groups and solid–solid phase transitions disclosed also by differential thermal analysis and differential scanning cal…
This article presents a self-consistent Poisson–Schrödinger calculation based on either the Hartree or the density functional theory for silicon quantum dots surrounded by silicon dioxide. These models can treat any shape of confining potential and take into account the different effective masses and permittivities of…
The adsorption of negatively charged polyelectrolyte and a polyampholyte to patterned surfaces has been investigated by using off-lattice Monte Carlo simulations. The surface is decorated by stripe and checkerboard patterns of mixed charges. The polymer has periodic charge segments which can potentially match the peri…
Nanoporous organosilicas have been synthesized by the acid-catalyzed hydrolysis and condensation of bis(triethoxysilyl)ethane (BTSE) using a hydrothermal approach. Cetyltrimethylammonium chloride (CTAC), polyoxyethylene(10) cetyl ether (Brij 56), and polyoxythylene(10) stearyl ether (Brij 76) were employed as structur…
The metastable β phase undergoes two order–disorder transitions during quenching from high temperature in Cu-based shape memory alloys. First, it undergoes a B2 ordering at nearest neighbors and then a second one at next-nearest neighbors that has not been clearly established. Neutron powder diffraction measurements h…
The electropolymerization of polysiloxane-functionalized pyrrole or poly(methyl-(undec-pyrrole-1-yl-decyl)-siloxane), to form conjugated network polymer films, is described. The “precursor polypyrrole” was electropolymerized using dynamic cyclic voltammetry (CV) on a flat conducting substrate electrode, resulting in c…
We have studied single crystals of β-Si3N4 with polarization-resolved Raman spectroscopy in order to unambiguously obtain the symmetry character of zone center optical phonon modes. By applying ultraviolet excitation radiation, approaching resonance condition, we have overcome the usual difficulties with overwhelming…
An off-lattice bead–spring model of a polymer solution in a container with impenetrable walls is used to study the depletion interaction of a colloid particle with the planar wall by means of a Monte Carlo simulation. As expected, this interaction is found to depend essentially on the ratio ρ=R/Rg of the particle radi…
The dielectric behavior and the main features of the diffuse phase transition of nondoped and rare earth (La, Nd, or Gd) doped Sr0.61Ba0.39Nb2O6 relaxor ferroelectric ceramics were carefully investigated. The dopant incorporation gives rise to one continuous decrease of the temperatures of maximum dielectric permittiv…
The correspondence between the Stokes and anti-Stokes Raman D band of graphitic materials in general, and bundles of single-wall carbon nanotubes (SWCNT's) in particular is investigated using the double resonance theory. The D band of bundles of SWCNT's is determined by the Van Hove singularity enhanced double-resonan…
The effects of chemical, plasma, and reactive ion etching (RIE) treatments on the adhesion of Cu and Cr/Cu to the multifunctional polymer were investigated. The adhesion was measured with the newly developed pull test. The polymer surfaces were characterized by the x-ray photoelectron spectroscopy, atomic force micros…
The magnetocaloric effect of a La2/3(Ca,Pb)1/3MnO3 single crystal was examined. From the measurements of isothermal magnetization and heat capacity around the Curie temperature, we have calculated the maximum isothermal magnetic entropy change as ∼7.5 J/kg K and the adiabatic temperature changes as ∼5.6 K, near room t…
The thermodynamic interactions in anionically synthesized poly(styrene- block -ferrocenyldimethylsilane) (SF) copolymers were examined using birefringence, small-angle X-ray and neutron scattering (SAXS and SANS). We show that birefringence detection of the order−disorder transition is possible in colored samples prov…
Abstract Two unsymmetrical and kink non‐coplanar heterocyclic diamines, 1,2‐dihydro‐2‐(4‐aminophenyl)‐4‐[4‐(4‐aminophenoxy)phenyl](2 H )phthalazin‐1‐one and 1,2‐dihydro‐2‐(4‐aminophenyl)‐4‐[4‐(4‐aminophenoxy)‐3,5‐dimethylphenyl](2 H ) phthalazin‐1‐one, were successfully synthesized by readily available heterocyclic bi…
Unusual copolymers were prepared by Candida antarctica Lipase B (Novozyme-435) catalyzed copolymerization of ω-pentadecalactone (PDL) with trimethylene carbonate (TMC). Atypical solid-state properties were revealed by thermogravimetric analysis, differential scanning calorimetry (DSC), and X-ray diffraction analyses.…
The polycondensation of 1a in the presence of 2 as an initiator and 18-crown-6 proceeded in a chain-polymerization manner in sulfolane at 120 °C to yield poly(ether sulfone) having defined molecular weights and low polydispersities.
The response of alloys based on the intermetallic compound NiTi to high-strain-rate and shock loading conditions has recently attracted attention. In particular, similarities between it, and other shape memory materials such as the alloy U–6%Nb in the propagation of the plastic wave in Taylor cylinders are of signific…
Dendron rod−coil molecules are a novel supramolecular building block, comprising a dendritic unit, a rodlike unit, and a coil unit ( J. Am. Chem. Soc. 2001, 123, 4105). It was proposed that in solution these molecules assemble into ribbonlike aggregates of high aspect ratio. We report here on the self-assembly of DRC-…
Small-angle neutron scattering (SANS) experiments were conducted on a 25 vol % blend of a poly(ethylene- block -head-to-head propylene) copolymer (PE−PP) in polyisobutylene (PIB). PE/PIB and PE/PP chains are incompatible (the Flory−Huggins interaction parameter χ > 0), while PIB and PP are compatible (χ < 0) at low te…
We study the layer-by-layer assembly and properties of polyelectrolyte multilayers containing anionic and cationic poly(alkoxythiophene) derivatives, poly(3-(3‘-thienyloxy)propanesulfonate) (P3TOPS) and poly(3-(3‘-thienyloxy)propyltriethylammonium) (P3TOPA), together with poly(diallyldimethylammonium chloride) (PDADMA…