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111.
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A new carbon composite electrode material, based on dispersing glassy carbon (GC) microparticles into methyltrimethoxysilane-derived sol, is described in the present paper. The resulting glassy carbon ceramic composite electrodes (GCCEs) combine the electrochemical properties of GC with the advantages of composite electrodes, and thus offer high electrochemical reactivity, low background current and are easy to prepare, modify and renew. The new material has a low double-layer capacitance and a wide potential window. Scanning electron microscopy (SEM) images indicate significant difference in the structure of GCCE and carbon ceramic composite electrode (CCE). The electrochemical properties and advantages of GCCE should find broad utility in electroanalysis. 相似文献
113.
We give a formal Laurent series proof of Andrews's -Dyson Conjecture, first proved by Zeilberger and Bressoud.
114.
We use recently developed effective field theory techniques to calculate the third order post-Newtonian correction to the spin-spin potential between two spinning objects. This correction represents the first contribution to the spin-spin interaction due to the nonlinear nature of general relativity and will play an important role in forthcoming gravity wave experiments. 相似文献
115.
Carlitz, Handa, and Mohanty proved determinantal formulas for counting partitions contained in a fixed bounding shape by area. Gessel and Viennot introduced a combinatorial method for proving such formulas by interpreting the determinants as counting suitable configurations of signed lattice paths. This note describes an alternative combinatorial approach that uses sign-reversing involutions to prove matrix inversion results. Combining these results with the classical adjoint formula for the inverse of a matrix, we obtain a new derivation of the Handa–Mohanty determinantal formula. 相似文献
116.
Raw space-based gravitational-wave data like laser interferometer space antenna's (LISA) phase measurements are dominated by laser frequency noise. The standard technique to make this data usable for gravitational-wave detection is time-delay interferometry (TDI), which cancels laser noise terms by forming suitable combinations of delayed measurements. To do so, TDI relies on inter-spacecraft distances and on how laser noise enters the interferometric data. The basic concepts of an alternative approach which does not rely on independent knowledge of temporal correlations in the dominant noise recently introduced. Instead, this automated principal component interferometry (aPCI) approach only assumes that one can produce some linear combinations of the temporally nearby regularly spaced phase measurements, which cancel the laser noise. Then the data is let to reveal those combinations, thus providing a set of laser-noise-free data channels. The authors' previous approach relies on the simplifying additional assumption that the filters which lead to the laser-noise-free data streams are time-independent. In LISA, however, these filters will vary as the constellation armlengths evolve. Here, a generalization of the basic aPCI concept compatible with data dominated by a still unmodeled but slowly varying dominant noise covariance is discussed. Despite its independence on any model, aPCI successfully mitigates laser frequency noise below the other noises' level, and its sensitivity to gravitational waves is the same as the state-of-the-art second-generation TDI, up to a 2% error. 相似文献
117.
Antibacterial effect of composite resins containing quaternary ammonium polyethyleneimine nanoparticles 总被引:1,自引:0,他引:1
Ira Yudovin-Farber Nurit Beyth Ervin I. Weiss Abraham J. Domb 《Journal of nanoparticle research》2010,12(2):591-603
Quaternary ammonium polyethyleneimine (QA-PEI)-based nanoparticles were synthesized by crosslinking with dibromopentane followed
by N-alkylation with various alkyl halides and further N-methylation with methyl iodide. Insoluble pyridinium-type particles
were prepared by suspension polymerization of 4-vinyl pyridine followed by N-alkylation with alkyl halides. Polyamine-based
nanoparticles embedded in restorative composite resin at 1% w/w were tested for antibacterial activity against Streptococcus mutans using direct contact test. Activity analysis revealed that the alkyl chain length of the QA-PEI nanoparticles plays a significant
role in antibacterial activity of the reagent. The most potent compound was octyl-alkylated QA-PEI embedded in restorative
composite resin at 1% w/w that totally inhibited S. mutans growth in 3-month-aged samples. This data indicates that restorative composite resin with antibacterial properties can be
produced by the incorporation of QA-PEI nanoparticles. 相似文献
118.
Low dielectric constant nanocomposite thin films based on silica nanoparticle and organic thermosets
Qinghuang Lin Stephen A. Cohen Lynne Gignac Brian Herbst David Klaus Eva Simonyi Jeffrey Hedrick John Warlaumont Hae-Jeong Lee Wen-li Wu 《Journal of polymer science. Part A, Polymer chemistry》2007,45(12):1482-1493
Low dielectric constant (low-k) nanocomposite thin films have been prepared by spin coating and thermal cure of solution mixtures of one of two organic low-k thermoset prepolymers and a silica nanoparticle with an average diameter of about 8 nm. The electrical, the mechanical, and the thermomechanical properties of these low-k nanocomposite thin films have been characterized with 4-point probe electrical measurements, nanoindentation measurements with an atomic force microscope, and specular X-ray reflectivity. Addition of the silica nanoparticle to the low-k organic thermosets enhances both the modulus and the hardness and reduces the coefficient of thermal expansion of the resultant nanocomposite thin films. The enhancements in the modulus of the nanocomposite thin films are less than those predicted by the Halpin-Tsai equations, presumably due to the relatively poor interfacial adhesion and/or the aggregation of the hydrophilic silica nanoparticles in the hydrophobic organic thermoset matrices. The addition of the silica nanoparticle to the low-k organic thermoset matrices increases the relative dielectric constant of the resultant nanocomposite thin films. The relative dielectric constant of the nanocomposite thin films has been found to agree fairly well with an additive formula based on the Debye equation. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1482–1493, 2007 相似文献
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