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。
Cerium dioxide is an insulating material that is important in various fields of catalysis and often used as an oxygen reservoir. The (111) surface of CeO 2 is catalytically active and we study this surface in its various oxidation states by dynamic force microscopy, an analysis that may eventually help to establish st…
Two elastin-like poly(pentapeptides), poly(AV1GV2P) and poly(G1V1G2V2P), have been studied in water and in solid state by ATR FTIR and Raman spectroscopy in combination with model ab initio calculations. In aqueous solutions below the transition temperature T(t), a part of the amide groups and of the methyl groups of…
A unique 2:1 cocrystal of mixed Cu(I)/Cu(II) complexes [Cu(I)(H2CPz2)(MeCN)2](ClO4) (1) and [Cu(II)(H2CPz2)2(ClO4)2] (4), a novel ferromagnetic ClO(4-)-bridged bis(mu-hydroxo)dicopper(II) complex, [Cu2(H2CPz2)2(OH)2(ClO4)](ClO4)(CH3CN)(0.5) (5), and a bischelated copper(I) complex, [Cu(H2CPz2)2](ClO4) (2), prepared fr…
Microorganisms are believed to create microenvironments leading to reaction products not predictable from equilibrium thermodynamics and to unique biomineral morphologies. Unambiguous evidence for such environments is, however, rare in natural samples. We have used scanning transmission x-ray microscopy and spectromic…
We report a stressed liquid crystal (SLC) that produce a large shift in phase retardation at submillisecond speeds. The SLC consists of uniformly aligned micro-domains of a liquid crystal dispersed in a polymer structure. Mechanical stress produces uniform alignment, essentially eliminates light scattering, and substa…
Abstract Reflection, emission and luminescence spectra of Czochralski grown molybdate crystals, i.e. MgMoO 4 , CaMoO 4 and CdMoO 4 have been investigated over a 8–295 K temperature range using VUV synchrotron radiation. Preliminary interpretation of the spectroscopic properties has been carried out on the basis of pre…
Supramolecular nanowires are specifically self-assembled from adenosine 5'-triphosphate (ATP) and dichloro-substituted thiacarbocyanine dyes. Spectral blue-shift and induced circular dichroism with exciton coupling are observed upon mixing the dye and ATP molecules in water. These observations indicate the formation o…
The low-frequency dielectric response of hole-doped insulators ${\mathrm{L}\mathrm{a}}_{2}{\mathrm{C}\mathrm{u}}_{1\ensuremath{-}x}{\mathrm{L}\mathrm{i}}_{x}{\mathrm{O}}_{4}$ and ${\mathrm{L}\mathrm{a}}_{2\ensuremath{-}x}{\mathrm{S}\mathrm{r}}_{x}{\mathrm{N}\mathrm{i}\mathrm{O}}_{4}$ shows a large dielectric constant…
Nitrogen (N)-doped carbon nanotubes (CNTs) were heated to 1000 degrees C under an ultrahigh vacuum. X-ray photoelectron spectroscopy (XPS) and X-ray absorption near-edge structure (XANES) reveal three different N structures; graphitelike, pyridine-like, and molecular N(2). The vibrationally resolved XANES peaks of N(2…
The absorption and emission spectra of most luminescent, pi-conjugated, organic molecules are the mirror image of each other. In some cases, however, this symmetry is severely broken. In the present work, the asymmetry between the absorption and fluorescence spectra in molecular systems consisting of para-linked pheny…
We calculate the optical attractive forces that occur between 30-nm Au or Ag nanocrystals when irradiated at visible wavelengths. These forces show resonances at dipolar plasmon wavelengths, similar to resonances in the near-field electromagnetic intensities. At MW/cm2 intensities, optical forces can be stronger than…
An amphiphilic oligonucleotide species ((C18)2-DNA) is presented as a generally useful reagent to display encoded tether sequences on the surface of phospholipid assemblies. (C18)2-DNA inserts into preformed vesicles and proteoliposomes of arbitrary composition, content, and origin using a simple and gentle procedure…
We determine the structural relaxations around paramagnetic impurities (Ti, Cr, Fe) in corundum (alpha-Al2O3), by combining x-ray absorption near edge structure (XANES) experiments and ab initio calculations. The structural relaxations are found to be very local. We then show that XANES is sensitive to small variation…
The temperature and voltage dependence of spin transport is theoretically investigated in a new type of magnetic tunnel junction, which consists of two ferromagnetic outer electrodes separated by a ferromagnetic barrier and a nonmagnetic (NM) metallic spacer. The effect of spin fluctuation in magnetic barrier, which p…
The structure, vibrational dynamics and thermodynamics of a chiral surface, Cu(532), has been calculated using a local approach and the harmonic approximation, with interatomic potentials based on the embedded atom method. The relaxation of atomic positions to the optimum configuration results in a complex relaxation…
Self-assembly of optically active gold nanoparticles with varying generations of poly(amidoamine) (PAMAM) dendrimers provides aggregates with controlled interparticle spacing, as determined using small-angle X-ray scattering (SAXS). This structural control provides a method for systematically shifting the surface plas…
The tricarboxylic acid (TCA) cycle plays two essential roles in metabolism. First, under aerobic conditions the cycle is responsible for the total oxidation of acetyl-CoA that is derived mainly from the pyruvate produced by glycolysis. Second, TCA cycle intermediates are required in the biosynthesis of several amino a…
Ion-irradiation-induced modifications of a periodic Pt/C multilayer system containing Fe impurity have been analyzed by transmission electron microscopy (TEM). The multilayer stack with 16 Pt/C layer pairs (period 4.23 nm) was fabricated on a glass substrate. A 2 MeV Au$^{2+}$ ion beam was rastered on the sample to ob…
For a set of fcc metals our total energy calculations, based on many body potentials, show that activation barriers for lateral manipulation of an adatom at a step edge depend on the tip/substrate composition. Of the six homogeneous systems studied, manipulation on stepped Ag(111) showed the lowest energy barrier for…
Polyhydroxyalkanoates (PHAs) are biodegradable aliphatic polyesters, known to be produced by many common microorganisms. Nodax is a recently introduced family of PHA copolymers comprising 3-hydroxybutyrate units and a relatively small amount of other medium chain length 3-hydroxyalkanoate (mcl-3HA) comonomers with sid…