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71.
Wong WW Vak D Singh TB Ren S Yan C Jones DJ Liaw II Lamb RN Holmes AB 《Organic letters》2010,12(21):5000-5003
A new class of self-assembling hexa-peri-hexbenzocoronene (HBC)-fullerene hybrid materials has been synthesized and characterized. Photoluminescence experiments indicate that energy transfer processes can be tuned in these donor-acceptor systems by varying the length and nature of the linker group. In preliminary device testing, ambipolar charge transport behavior is observed in organic field effect transistors, while single active component organic photovoltaic devices consisting of these materials achieved a maximum external quantum efficiency of 30%. 相似文献
72.
Wallace EV Stoddart D Heron AJ Mikhailova E Maglia G Donohoe TJ Bayley H 《Chemical communications (Cambridge, England)》2010,46(43):8195-8197
Two DNA bases, 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (hmC), marks of epigenetic modification, are recognized in immobilized DNA strands and distinguished from G, A, T and C by nanopore current recording. Therefore, if further aspects of nanopore sequencing can be addressed, the approach will provide a means to locate epigenetic modifications in unamplified genomic DNA. 相似文献
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75.
A Heuristic for Moment-Matching Scenario Generation 总被引:1,自引:0,他引:1
Kjetil Høyland Michal Kaut Stein W. Wallace 《Computational Optimization and Applications》2003,24(2-3):169-185
In stochastic programming models we always face the problem of how to represent the random variables. This is particularly difficult with multidimensional distributions. We present an algorithm that produces a discrete joint distribution consistent with specified values of the first four marginal moments and correlations. The joint distribution is constructed by decomposing the multivariate problem into univariate ones, and using an iterative procedure that combines simulation, Cholesky decomposition and various transformations to achieve the correct correlations without changing the marginal moments.With the algorithm, we can generate 1000 one-period scenarios for 12 random variables in 16 seconds, and for 20 random variables in 48 seconds, on a Pentium III machine. 相似文献
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77.
Michael Campbell Yatao Yang Peter A. Wallace A. Sheila Holmes-Smith 《Optical Review》1997,4(1):A111-A113
This paper reports the development and characterisation of a multipoint quasi-distributed optical fiber sensor for pH measurement. The system is based on a 170 m length of 200 μm core diameter plastic cladding silica fiber where sections of cladding have been removed and replaced with dye immobilised sol-gel glass to form sensing points. Evanescent wave excitation of a dye, immobilised within 2 mm long sections of cladding, enables the pH value of any spillage material to be determined by optical time domain reflectometry along the length of the fiber. The results suggest a spatial resolution of better than 2.5 meters for this fiber system and indicate that this arrangement could form the basis of a practical sensor/actuator system for chemical spillage, provided that suitable dye/analyte combinations are available. 相似文献
78.
Hughes MS McCarthy JE Marsh JN Arbeit JM Neumann RG Fuhrhop RW Wallace KD Znidersic DR Maurizi BN Baldwin SL Lanza GM Wickline SA 《The Journal of the Acoustical Society of America》2007,121(6):3542-3557
Qualitative and quantitative properties of the finite part, H(f), of the Shannon entropy of a continuous waveform f(t) in the continuum limit are derived in order to illuminate its use for waveform characterization. Simple upper and lower bounds on H(f), based on features of f(t), are defined. Quantitative criteria for a priori estimation of the average-case variation of H(f) and log E(f), where E(f) is the signal energy of f(t) are also derived. These provide relative sensitivity estimates that could be used to prospectively choose optimal imaging strategies in real-time ultrasonic imaging machines, where system bandwidth is often pushed to its limits. To demonstrate the utility of these sensitivity relations for this application, a study designed to assess the feasibility of identification of angiogenic neovasculature targeted with perfluorocarbon nanoparticles that specifically bind to alpha(v)beta3-integrin expression in tumors was performed. The outcome of this study agrees with the prospective sensitivity estimates that were used for the two receivers. Moreover, these data demonstrate the ability of entropy-based signal receivers when used in conjunction with targeted nanoparticles to elucidate the presence of alpha(v)beta3 integrins in primordial neovasculature, particularly in acoustically unfavorable environments. 相似文献
79.
Lloyd CW Wallace KD Holland MR Miller JG 《The Journal of the Acoustical Society of America》2007,122(1):91-96
The objective of this investigation is to introduce and validate a practical ultrasound source to be used in the investigation of the nonlinear material properties of liquids and soft tissues studied in vitro. Methods based on the progressive distortion of finite amplitude ultrasonic waves in the low megahertz frequency range are most easily implemented under the assumption of plane wave propagation. However, achieving an approximately planar ultrasonic field over substantial propagation distances can be challenging. Furthermore, undesired harmonic distortion of the ultrasonic field prior to insonification of the specified region of interest represents another serious limitation. This paper introduces an approach based on the use of the ultrasonic field emanating from a stainless-steel delay line. Both simulation and direct experimental measurement demonstrate that such a field exhibits relatively planar wave fronts to a good approximation (such that a 3-mm-diam receiver would be exposed to no more than 3 dB of loss across its face) and is free from the significant harmonic distortion that would occur in a conventional water path. 相似文献
80.
Electro‐oxidation and reduction of H2 on platinum studied by scanning electrochemical microscopy for the purpose of local detection of H2 evolution 下载免费PDF全文
Sina S. Jamali Simon E. Moulton Dennis E. Tallman Jan Weber Gordon G. Wallace 《Surface and interface analysis : SIA》2015,47(13):1187-1191
Electrochemical detection of H2 using scanning electrochemical microscopy (SECM) has shown to hold great promise as a sensitive characterization method with high spatial resolution for active surfaces generating H2. Herein, the factors contributing to the current that is measured by SECM in generation/collection mode for H2 detection are studied. In particular, the concentration gradient of H2 at the substrate, the H2/H+ recycling between the SECM tip and substrate and hemispherical profile of H2 diffusion has been discussed. It was postulated that H2/H+ recycling plays a dominant role in the oxidative current measured in generation/collection mode of SECM when the microelectrode is positioned in close vicinity of substrate. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献