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 molecular hyperpolarizabilities and electronic properties of some azulene-containing chromophores have been investigated by employing AM1/FF and ZINDO/S-CI approaches. The calculation results show good agreement with the experimental values. It is found that the nonalternant azulene ring can be regarded as a more…
Monolithic optically clear aluminosilicate and alumina gels can be prepared directly from aluminum nitrate (and tetraethoxysilane) dissolved in 1-propanol. The role of aluminum atoms in the formation of the gel networks has been investigated by 27 Al magic angle spinning nuclear magnetic resonance, infrared spectrosco…
We report on the highly exothermic solid-state reaction between hexachlorobenzene and calcium hydride. Once ignited by a thermal spike, the reaction displays a self-sustaining character in the CaH 2 /C 6 Cl 6 molar ratio of 3:18. The high temperatures reached, i.e., 2550−2900 K, ensure a complete breakdown of the arom…
The molecular third-order optical nonlinearity γ R (second hyperpolarizability or nonlinear refractive index) was measured for a series of sulfur-rich molecules: sulfur (S 8 ), carbon−sulfur compounds, and metal thiolate clusters. Z -scan techniques (pulse width 27 ps, wavelength 527 nm) were used to measure these pro…
This paper is the second segment of an investigation into the reaction products of laser-ablated lanthanide metal atoms with O 2 . There is general agreement with previous gas-phase and matrix infrared observations of neutral lanthanide monoxides; the frequencies of monoxide cations and anions are original to this wor…
Nanocomposites of montmorillonite mineral with poly-4-vinylpyridinium salts (1,2-form) the quaternized ionene polymer (1,6-form) and poly-4-vinylpyridine (neutral form) have been synthesized and characterized. Only one macromolecular sheet of poly-4-vinylpyridinium polyelectrolyte or the quaternized polyelectrolyte en…
X-ray diffraction analysis demonstrated that a PEN film annealed from 160 to 260 °C crystallizes in the α crystal form while crystallization of PEN directly from the melt results in the β crystal form when T c > 200 °C and in the α form at lower T c . Infrared spectra from PEN samples containing α, β, and amorphous ph…
Spin dependent single electron tunneling in a ferromagnetic double junction is investigated theoretically in the limit of incoherent sequential tunneling. The junction consists of a small nonmagnetic metallic grain with discrete energy levels, which is connected to two ferromagnetic electrodes. We have developed a new…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTPreparation of Macroporous Metal Films from Colloidal CrystalsPeng Jiang, Joel Cizeron, Jane F. Bertone, and Vicki L. ColvinView Author Information Department of Chemistry, Rice University Houston, Texas 77005 Cite this: J. Am. Chem. Soc. 1999, 121, 34, 7957–7958Public…
The reversibility, specificity, stability, and scaling of signal response to analyte mass were quantified for a porous silicon-based optical interferometric biosensor. The sensor system studied consisted of a thin layer (5μm) of porous silicon modified with Protein A. The system was probed with various fragments of an…
Vacuum emission of ballistic electrons from Au-SiO 2 -Si structures has been investigated for oxide layers of various thicknesses d ox = 13-500 nm. In particular for very thick layers and high field strength 5 MV cm -1 we measure electron energies up to 200 eV, that is 80% of the maximum ballistic drive energy E ball…
The photochromism of spiro[cyclohexadiene-indolines], the reversible bond cleavage at the spiro-carbon resulting in a colored merocyanine, is affected by solvent polarity. Photoexcited intramolecular charge transfer within the preserved spiro form of the molecule is favored in polar solvents, explaining the drop in me…
In this paper, a Stoner-Wohlfarth approach to magnetic hysteresis is used as a model for a ferromagnetic composite rod consisting of single domain `grains' with random orientations embedded in a non-magnetic matrix. The rod is considered to be under torsional stress, which means that the rod at each point on its outer…
Fourier transform-infrared studies have been carried out on the non-stoichiometric Ni-Zr substituted barium hexaferrite synthesized through the citrate precursor method. We observed approximately 30 bands, almost twice as many as reported for stoichiometric samples. These are attributed to the shifting of the vibratio…
The composite structure of glow peak 5 in LiF:Mg,Ti (TLD-100), has been investigated using optical bleaching by 310 nm (4 eV) light. The decay of composite peak 5 and the growth of peak 4 are described by two exponential components of the same mean lives for both peaks. Using computerized glow curve deconvolution and…
To date most of the microelectromechanical system (MEMS) devices have been based on silicon. This is due to the technological know-how accumulated on the manipulation, machining and manufacturing of silicon. However, only very few devices involve moving parts. This is because of the rapid wear arising from high fricti…
Micro-organisms such as bacteria and yeasts form CdS to detoxify toxic cadmium ions. Frequently, CdS particles formed in yeasts and bacteria were found to be associated with specific biomolecules. It was later determined that these biomolecules were present at the surface of CdS. This coating caused a restriction in t…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTA General Mechanism for CO Oxidation on Close-Packed Transition Metal SurfacesChangjun Zhang, Peijun Hu, and Ali AlaviView Author Information School of Chemistry The Queen's University of Belfast Belfast BT9 5AG, U.K. School of Mathematics and Physics The Queen's Unive…
The fabrication of micropatterned TiO2 films on deep UV patterned self-assembled monolayers (SAMs) of phenylsiloxane is described. The patterned SAM was immersed in an acidic, aqueous TiF62- solution to directly deposit crystalline TiO2 (anatase) onto both hydrophobic (masked) and hydrophilic (irradiated) surface regi…
Crystal structures of ethylene−vinyl alcohol copolymers (EVOH) with various vinyl alcohol (VA) compositions have been determined on the basis of the X-ray diffraction data measured for the uniaxially and doubly oriented sample specimens. The unit cells of EVOH with a VA content higher than 27 mol % are monoclinic of t…