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91.
Elham Doroodchi Thomas Michael Evans Behdad Moghtaderi 《Journal of nanoparticle research》2009,11(6):1501-1507
This article provides critical examinations of two mathematical models that have been developed in recent years to describe
the impact of nano-layering on the enhancement of the effective thermal conductivity of nanofluids. Discrepancy between the
two models is found to be an artefact of an incorrect derivation used in one of the models. With correct formulation, both
models predict effective thermal conductivity enhancements that are not significantly greater than those predicted by classical
Maxwell theory. This study indicates that nano-layering by itself is unable to account for the effective thermal conductivity
enhancements observed in nanofluids. 相似文献
92.
Local field surface plasmon excitation of pair arrays of silver nanospheres was studied using three-dimensional finite-difference time-domain method. The near-field enhancement was associated with the radius of nanosphere and the incident wavelength, the highest of which always appeared in the penultimate gaps, regardless of the number of the pairs. The surface plasmon resonance could be controlled and tuned by radius of nanosphere and incident wavelength. 相似文献
93.
J. Manjunath Swamy Narendra Kamath Anil Kumar Radha Shekar Nuggehally R. Srinivas Fjalar Kristjansson 《Biomedical chromatography : BMC》2010,24(5):528-534
Sensitivity enhancement via summation of multiple MRM transition pairs is gaining popularity in tandem mass spectrometric assays. Numerous validation experiments describing the assays for two model substrates, clopidogrel and ramiprilat, were performed. The quantitation of clopidogrel was achieved by the summation of transition pairs m/z 322.2 to m/z 212.0 and m/z 322.2 to m/z 184.0, while that of ramiprilat was achieved by the summation of transition pairs m/z 389.2 to m/z 206.1 and m/z 389.2 to m/z156.1. The use of summation approach achieved sensitivities of >2 fold for both compounds as compared with the reported single MRM transition pair assays. The validation experiments addressed some important assay development issues, such as: (a) lack of impact of matrix effect; (b) unequivocal verification of the percentage contribution of each MRM transition pair towards sensitivity; (c) sensitivity enhancement factor achieved by summation approach of MRM transition pairs; and (d) accurate prediction of quality control samples using summation approach vs a single MRM transition pair. In summary, the appropriateness of using two MRM transition pairs for quantitation was demonstrated for both clopidogrel and ramiprilat. Additionally, pharmacokinetic application of the MRM transition pair assays using a summation approach was established for the two compounds. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
94.
95.
Enhanced nonlinearity in photonic crystal fiber by germanium doping in the core region 总被引:2,自引:0,他引:2
Germanium doping in silica can be used as a method for nonlinearity enhancement.Properties of the enhanced nonlinearity in photonic crystal fiber(PCF)with a GeO2-doped core are investigated theoretically by using all-vector finite element method.Numerical result shows that the nonlinear coefficient of PCF is greatly enhanced with increasing doping concentration,furthermore,optimal radius of the doped region should be considered for the desired operating wavelength. 相似文献
96.
Free induction decay (FID) signals in solid state NMR measurements performed with magic angle spinning can often be extended in time by factors on the order of 10 by a simple pulsed spin locking technique. The sensitivity of a structural measurement in which the structural information is contained in the dependence of the integrated FID amplitude on a preceding evolution period can therefore be enhanced substantially by pulsed spin locking in the signal detection period. We demonstrate sensitivity enhancements in a variety of solid state NMR techniques that are applicable to selectively isotopically labeled samples, including 13C-15N rotational echo double resonance (REDOR), 13C-13C dipolar recoupling measurements using the constant-time finite-pulse radio-frequency-driven recoupling (fpRFDR-CT) and constant-time double-quantum-filtered dipolar recoupling (CTDQFD) techniques, and torsion angle measurements using the double quantum chemical shift anisotropy (DQCSA) technique. Further, we demonstrate that the structural information in the solid state NMR data is not distorted by pulsed spin locking in the detection period. 相似文献
97.
193nm光刻曝光系统的现状及发展 总被引:3,自引:0,他引:3
投影曝光工艺是集成电路制造过程中的关键环节,曝光系统的工艺水平已成为衡量微电子制造技术的重要标志。重点介绍了目前193nm光刻设备曝光系统的发展现状和趋势,以及为提高曝光质量所采用的相关分辨率增强技术;通过分析曝光系统的构成和其中的关键技术,探讨了国内研制相关曝光设备所面临的挑战。 相似文献
98.
99.
Stephen E. Rose Stephen J. Wilson Fernando O. Zelaya Stuart Crozier David M. Doddrell 《Magnetic resonance imaging》1994,12(8):1183-1190
A method that incorporates cardiorespiratory-gated 2DFT spin-echo imaging with blood flow enhancement suppression is described which enables high resolution microimaging of the rodent heart. This methodology was applied to obtain in vivo cardiac mouse and rat images with in-plane resolutions of 100–200 μm using high field vertical bore magnet systems. Suppression of intraventricular blood flow enhancement was achieved using a combined spin-echo/gradient-refocussed sequence to dephase magnetization from flowing spins prior to imaging. 相似文献
100.
Mishkovsky M Frydman L 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2005,173(2):344-350
A new protocol for processing the data arising in ultrafast 2D NMR is discussed and exemplified, based on the interlaced Fourier transformation. This approach is capable of dealing in a single, combined fashion, with the two mirror-imaged interferograms arising in this kind of experiment as a result of the acquisition of a train of magnetic field gradient echoes. By combining all the acquired data points into a common Fourier processing procedure the spectral width along the direct-acquisition domain becomes effectively doubled, giving the opportunity of employing acquisition gradients that are approximately half as strong as hitherto required. This in turn should lead to an overall enhancement in the signal-to-noise ratio of the experiment of ca. 2, as well as to improvements in the achievable digital resolution. These expectations were tested by carrying out a series of homo- and heteronuclear ultrafast 2D NMR acquisitions, and found systematically fulfilled. The robustness and conditions that allow the interlaced numerical procedure to be implemented in routine analytical applications were explored and are briefly discussed. 相似文献