Duncan Roper

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Visible radiation at resonant frequencies is transduced to thermal energy by surface plasmons on gold nanoparticles. Temperature in </=10-microliter aqueous suspensions of 20-nanometer gold particles irradiated by a continuous wave Ar+ ion laser at 514 nm increased to a maximum equilibrium value. This value increased in proportion to incident laser power(More)
Problems with unit execution time (UET) tasks and two identical parallel processors have received a great deal of attention in scheduling theory. In contrast to the conventional models, where each task requires only one processor, we consider a situation when a task may require both processors simultaneously. Following Lloyd, we term such task systems(More)
Gold nanoparticle arrays created with electroless gold plating provide a unique means of transforming nanocylinders usually formed in electron beam lithography to spherical nanoparticles. Alone, electroless gold plating is not selective to the substrate and results in the formation of a gold film on all exposed surfaces of an electron beam patterned sample,(More)
Electroless gold island thin films are formed by galvanic replacement of silver reduced onto a tin-sensitized silica surface. A novel approach to create nanoparticle ensembles with tunable particle dimensions, densities, and distributions by thermal transformation of these electroless gold island thin films is presented. Deposition time is adjusted to(More)
Intrinsic sorption rates of ligand/receptor binding have been measured by surface plasmon resonance (SPR) using response factors for deposition of proteins or smaller molecules on planar surfaces. In this study generalized expressions for SPR response factor and effective refractive index are developed to measure rates of analyte sorption onto 3-D surfaces.(More)
Plasmonic nanostructures enable microscopic optical manipulation such as light trapping in photonic devices. However, integration of embedded nanostructures into photonic devices has been limited by tractability of nanoscale and microscale descriptions in device architectures. This work uses a linear algebraic model to distinguish geometric optical(More)
Aqueous, acid solutions containing balanced amounts of a strong reductant (formaldehyde, HCHO) and a strong oxididant (N-bromosuccinimide, NBS) allow the first sensitive spectrophotometric analysis of monovalent gold ion, Au(I), using oxidation of color reagent 3,3',5,5'-tetramethylbenzidine dihydrochloride (TMB). This new method enables various oxidation(More)
Intrinsic adsorption rates of whole adenovirus type 5 (Ad5) onto a diethylaminoethyl (DEAE) anion exchange surface are measured for the first time by surface plasmon resonance (SPR). Fitting SPR sensorgrams to a two-compartment mass transport reaction model distinguishes intrinsic adsorption rates from slow diffusive Ad5 mass transport. Ad5 is a widely used(More)
Combining a modified two-step chemical etch method with equations to predict etch parameters and photon-plasmon phase-matching resulted in single-mode tapered optical fibers (TOFs) to optimize electromagnetic field enhancement. The phase-matching equation was used to identify the angle of incidence near the TOF cutoff radius at which surface plasmon(More)
Polymer thin films containing gold nanoparticles (AuNPs) are of growing interest in photovoltaics, biomedicine, optics, and nanoelectromechanical systems (NEMs). This work has identified conditions to rapidly reduce aqueous hydrogen tetrachloroaurate (TCA) that is diffusing into one exposed interface of a partially cured polydimethylsiloxane (PDMS) thin(More)