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 formation of multilayer films of organothiol-stabilized gold nanoparticles and polyelectrolyte, synthesized using the "layer-by-layer" technique, has been investigated. The formation of such films requires the alternation of surface charge with each layer deposited and is thus amenable to study by the Kelvin probe…
The Zn K-edge extended X-ray absorption fine structure (EXAFS) spectra, of the dapE-encoded N-succinyl-l,l-diaminopimelic acid desuccinylase (DapE) from Haemophilus influenzae have been recorded in the presence of one or two equivalents of Zn(II) (i.e. [Zn_(DapE)] and [ZnZn(DapE)]). The Fourier transforms of the Zn EX…
The nitrogen bonding in hard and elastic amorphous carbon nitride $(a\ensuremath{-}{\mathrm{CN}}_{x})$ films is examined with ${}^{15}\mathrm{N},$ ${}^{13}\mathrm{C},$ and ${}^{1}\mathrm{H}$ nuclear magnetic resonance (NMR) spectroscopy. Films were deposited by dc magnetron sputtering, in a pure nitrogen discharge on…
A superposition of the Pauli and orbital couplings of a high magnetic field to charge carriers in a charge-density-wave (CDW) system is proposed to give rise to transitions between subphases with quantized values of the CDW wave vector. By contrast to the purely orbital field-induced density-wave effects which require…
Abstract Two, functional, cyclic carbonate monomers, 5‐methyl‐5‐methoxycarbonyl‐1,3‐dioxan‐2‐one and 5‐methyl‐5‐ethoxy carbonyl‐1,3‐dioxan‐2‐one, were synthesized starting from 2,2‐bis(hydroxymethyl) propionic acid. The ring‐opening polymerization of the cyclic carbonate monomers in bulk with stannous 2‐ethylhexanoate…
Halohydrin dehalogenase (HheC) from Agrobacterium radiobacter AD1 is a homotetrameric protein containing four tryptophan residues per subunit. The fluorescence properties of the enzyme are strongly influenced by halide binding. To examine the role of the tryptophans (W139, W192, W238, and W249) in halide binding and c…
Selective electroless nickel plating was demonstrated at the micron scale on 3-D surface microstructures using a two-step method. The 3-D patterned and functional surface microstructures consisted of microparticles, polyelectrolyte multilayers, and self-assembled monolayers, which were built by microcontact printing a…
Abstract The thermal stability, degradation kinetics and lifetime‐prediction of a luminescent conducting polymer, poly[2‐methoxy‐5‐(2‐ethylhexyloxy)‐1,4‐phenylenevinylene] (MEH‐PPV), are investigated. The derivative thermogravimetry curves indicate a double‐stage decomposition process in a nitrogen atmosphere, and a m…
The new semiempirical methods, PDDG/PM3 and PDDG/MNDO, have been parameterized for halogens. For comparison, the original MNDO and PM3 were also reoptimized for the halogens using the same training set; these modified methods are referred to as MNDO' and PM3'. For 442 halogen-containing molecules, the smallest mean ab…
The surfactant-encapsulated europium-substituted heteropolyoxotungatate, (DODA) 11 H 2 [Eu(SiW 11 O 39 ) 2 (H 2 O) 4 ] (SEC-2), is structurally characterized in detail and its photophysical behaviors are investigated. The DODA alkyl chains of SEC-2 are well ordered in the solid state, solvent-casting film, and Langmui…
The conversion of NO to N2 is a key issue encountered in the control of emission from vehicles. The selectivity of NO reduction on two platinum group metals, Ir and Pt, including the close-packed flat surface and the monatomic steps are extensively studied within the first-principles density functional theory framewor…
Photochromic diarylethene derivatives containing 2,4-diphenylphenyl substituents formed stable amorphous solids and showed reversible solid-state photochromism. Refractive indices of the amorphous films changed reversibly with the photochromic reactions as much as Δ n = 0.028 at 817 nm. Changes in both absorption band…
Platelet adhesion to the surfaces of biomaterials preadsorbed with plasma previously has been shown to be mediated exclusively by surface-bound fibrinogen and does not seem to involve the other adhesion proteins in plasma (Tsai et al., J Biomed Mater Res 2002;60:348-359). In this study, the influence of surface-bound…
We report in this study that an oxoiron(IV) porphyrin complex bearing electron-deficient porphyrin ligand, (TPFPP)FeIV=O (TPFPP = meso-tetrakis(pentafluorophenyl)porphinato dianion), shows reactivities similar to those found in oxoiron(IV) porphyrin pi-cation radicals. In the epoxidation of olefins by the (TPFPP)FeIV=…
Gaps in the voluminous data on pyrolysis of polyethylene that impede mechanistic understanding are highlighted, especially for H:C material balances, product distributions at varying conversions in isothermal closed systems, and inconsistencies between GC and FIMS analyses of products with lower volatility. Thermochem…
We present measurements of Shubnikov-de Haas oscillations in arrays of bismuth nanowires with diameters comparable to the Fermi wavelength. For 80-nm wires the hole concentration is less than 30% of that for bulk Bi, consistent with current models of quantum confinement effects. However, 30-nm wires nanowires which ar…
We propose that localized defects in magnetic semiconductors act as deep impurities and can be described by the Anderson model. Within this model, hybridization of d-orbitals and p-orbitals gives rise to a non-RKKY indirect exchange mechanism, when the localized d-electrons are exchanged through both conduction and va…
Semiconductor quantum wires constitute a promising thermoelectric material because of the increase of the electronic density of states in low-dimensional materials. We studied the magnetic-field-dependent resistance and Seebeck coefficient of a high-density network of 6-nm-diameter wires of Bi and of Bi(1-x)Te(x), x=0…
In dynamic Monte Carlo simulations, using for example the Metropolis dynamic, it is often required to simulate for long times and to simulate large systems. We present an overview of advanced algorithms to simulate for larger times and to simulate larger systems. The longer-time algorithm focused on is the Monte Carlo…
Compressed copper powder has a very large electrical resistance (1MOhm), due to the oxide layer on grains (100 micro m). We observe that its voltage-current U-I characteristics are nonlinear, and undergo an instability, from an insulating to a conductive state at relatively small applied voltages. Current through the…