Materials Literature
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A synthesis method is introduced for very small uniform gold particles (diameter less than 5 nm), based on the reduction of hydrogen tetrachloroaurate(III) in ethanol in the presence of (γ-mercaptopropyl)trimethoxysilane (MPS). The surface layer of MPS molecules gives the gold particles a high colloidal stability and…
The structures of different celluloses (microcrystalline and native) were characterized by diffuse reflectance infrared spectroscopy (DRIFT), analyzing the bands due to O−H stretching, C−O stretching, and C−H bending modes. The respective crystallinities were determined as 73 ± 2% and 40 ± 2%, and the crystalline stru…
Prolyl 4-hydroxylase (proline hydroxylase, EC 1.14.11.2) catalyzes the formation of 4-hydroxyproline in collagens. The vertebrate enzyme is an alpha2beta2 tetramer, the beta subunit of which is identical to protein disulfide-isomerase (PDI, EC 5.3.4.1). We report here on cloning of the recently discovered alpha(II) su…
Optical memory systems that exhibit multiplexity and multifunctionality may allow high‐density storage and multiple addressing and readout. In a first step towards such systems, it is shown that two‐component mixtures of dithienylethene compounds (e.g., see Figure) can be switched reversibly between four different col…
Polarizing beam splitters that use the anisotropic spectral reflectivity (ASR) characteristic of high-spatial-frequency multilayer binary gratings have been designed, fabricated, and characterized. Using the ASR effect with rigorous coupled-wave analysis, we design an optical element that is transparent for TM polariz…
From an experimental point of view and more particularly in heterogeneous catalysis, the L III white line is at the center of electronic charge transfer either between either the nanometer scale metallic particle and the support or between the two metals which are present inside the cluster. In this work, we show that…
We present an experimental study of the growth patterns of directionally solidified thin samples of the lamellar eutectic alloy CBr${}_{4}$-C${}_{2}$Cl${}_{6}$ as a function of the pattern wavelength $\ensuremath{\lambda}$, the solidification velocity $V$, and the alloy concentration $C$, within the so-called planar c…
Double layer capacitors made with activated carbon electrodes and filled with nonaqueous electrolytes at different salt concentrations have been studied. It was found that the performance of the capacitor is strongly dependent on the salt concentration in the electrolyte. For electrolytes with high salt concentrations…
By controlling the angular relation of the substrate surface with respect to the incoming vapor direction in an evaporation deposition system, it is possible to engineer the morphology of thin films. Sculptured nematic thin films result under low adatom mobility conditions when the substrates are rotated about an axis…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEstablishment and Successful Application of the σJJ• Scale of Spin-Delocalization Substituent ConstantsXi-Kui JiangView Author Information Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Feng-Lin Lu, Shanghai 200032, China Cite this: Acc. Chem. Res.…
Thermal properties, structure, and dynamics of supercooled water in porous silica of two different pore sizes (30 and 100 Å) have been investigated over a temperature range from 298 down to 193 K by differential scanning calorimetry (DSC), neutron diffraction, neutron quasi-elastic scattering, and proton NMR relaxatio…
Superresolution phase-only pupil filters designed to utilize the degrees of freedom made available by diffractive optics technology are investigated theoretically. These so-called diffractive superresolution elements improve the quality of the superresolved diffraction pattern from the point of view of Strehl ratio, r…
The one-dimensional chain complex [Cu(2)(&mgr;(2)-1,1-N(3))(2)(&mgr;(2)-1,3-NO(3))(2)(&mgr;(2)-1,3-Me(3)NCH(2)CO(2))(2)](n)() (1) contains three different bridge groups, &mgr;(2)-1,1-azide (end-on), &mgr;(2)-nitrate, and &mgr;(2)-syn,syn-carboxylate, arranged so that the azide and carboxylate groups bridge equatoriall…
A strictly anaerobic thiosulfate-reducing bacterium was isolated from a corroding offshore oil well in Congo and was designated strain SEBR 4207T. Pure culture of the strain induced a very active pitting corrosion of mild steel, with penetration rates of up to 4 mm per year. This constitutes the first experimental evi…
How copolymers affect the crystallization of inorganic materials has been studied, using as an example the effect of poly(ethylene oxide)‐ block ‐poly(methacrylic acid) (PEO‐ bl ‐PMAA) on calcite (CACO 3 ). It si shown that the presence of PEO‐ bl ‐PMAA can lead to a drastic alteration of the crystal habit of calcite,…
Diarylethene derivatives, which have an optically active l - or d -menthyl group at the 2-position of benzo[ b ]thiophene ring, were synthesized. Irradiation with 450 nm light in solution led to the formation of diastereomer pairs of the closed-ring forms. The product ratio of the diastereomers was dependent on solven…
Abstract The shear and compressive properties of aggregated alumina particles are determined as functions of volume fraction and the strength of the interparticle attraction. Over a range of volume fractions, yield stresses, τ y , elastic moduli, the strain delimiting the extent of the linear elastic response, and com…
We have used powder X-ray diffraction, diffuse reflectance Fourier-transform infrared, 29 Si MAS NMR, N 2 adsorption, and transmission electron microscopy to examine the role of the concentration of silica, the surfactant, and the reaction time in the synthesis of high-quality silica mesoporous molecular sieve MCM-48.…
We report the synthesis and electrochemical polymerization of a series of bisheterocycle- N -substituted carbazoles. These monomers exhibit low peak oxidation potentials ( E p,m ) which range from 0.15 to 0.46 V vs Ag/Ag +, indicating facile polymerization. Repeated scan electrochemical polymerization for these monome…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEfficiency of Proton Transfer Catalysis in Models and Enzymes†Anthony J. KirbyView Author Information University Chemical Laboratory, Cambridge CB2 1EW, U.K. Cite this: Acc. Chem. Res. 1997, 30, 7, 290–296Publication Date (Web):July 15, 1997Publication History Received6 Marc…