4,800 research outputs found
Level repulsion in hybrid photonic-plasmonic microresonators for enhanced biodetection
We theoretically analyse photonic-plasmonic coupling between a high Q
whispering gallery mode (WGM) resonator and a core-shell nanoparticle. Blue and
red shifts of WGM resonances are shown to arise from crossing of the photonic
and plasmonic modes. Level repulsion in the hybrid system is further seen to
enable sensitivity enhancements in WGM sensors: maximal when the two resonators
are detuned by half the plasmon linewidth. Approximate bounds are given to
quantify possible enhancements. Criteria for reactive vs. resistive coupling
are also established
A study on gas molecule-solid surface interaction satellite experiment feasibility Final report
Feasibility of conducting gas-solid surface interaction experiments on earth satellit
Advantages of the diffuser-augmented wind turbine
Performance optimization for a wind turbine is realized by using a shrouded diffuser to produce up to twice the power of unshrouded turbines of the same diameter. The diffuser converts the kinetic energy of the flow downstream of the rotor into a pressure rise and thus makes it possible for the rotor to capture airflow from a free stream tube area that is greater than that from the rotor itself. The flow velocity through the shrouded rotor is 20 to 60 percent greater than the free wind velocity as opposed to 67 percent less for the unshrouded case. The diffuser also makes it possible to accommodate very high wind speeds without the need of variable pitch in the rotor blades
Upper atmosphere interactions with spacecraft
Rarefied gas-surface interactions effects on satellite orbital position, attitude, and lifetime between 150 and 330 k
Cluster-Grouping, Co-Teaching, and Professional Learning Communities Focused on Mathematics Instruction Lead to Improved Engagement and Achievement in Mathematics for Students
The Performance Implications of Planning, Implementation, and Evolution of Market-oriented Strategy by Top Management
Participating in the growing research stream involving the market orientation-performance relationship, this investigation explores the impact of firms’ planning, implementation, and evolution of market orientation on financial performance. A longitudinal approach is used to capture the formation and evolution of market orientation. Evidence of market orientation as depicted in top management’s stated strategy is assessed through content analysis of 150 SEC filings (S-1s and 10-Ks) of seventy-five initial public offering (IPO) firms. The sample covers companies that went public in the years 2001-2003, and the study spans a six-year period from 2001-2007. Customer and competitor orientation are independent variables tested to predict stock return. Moderator variables of firm size, top-management-team (TMT) heterogeneity, services or manufacturing industry, and industry competitive intensity are tested in a series of regression analyses. The study involves a unique combination of features in that: 1) the market orientation of top management is captured; 2) the market orientation formation and evolution is captured; 3) secondary archival data is used in the analysis; 4) objective performance measures are utilized; 5) data from multiple industries is analyzed; 6) factors that moderate the market orientation performance relationship are studied. Contributions of this study are that it: 1) builds on the work of Gebhardt, Carpenter and Sherry (2006) using longitudinal analysis to capture the dynamic nature of the market orientation; 2) establishes evidence of variation of the market orientation across time; 3) examines the division of market orientation as separate constructs of customer and competition; 4) provides insight about important moderators of the relationship; 5) moves literature towards a foundation for a more general theory of market orientation by providing some further evidence of the construct’s relation to financial performance. Results of regression analysis provide support for customer orientation leading to superior financial performance. Significant moderator variables in this relationship include manufacturing vs. service firms, top-management-team (TMT) heterogeneity, and firm size. Unexpected results are found for competitor orientation and some moderator results are not significant
Dielectric tuning and coupling of whispering gallery modes using an anisotropic prism
Optical whispering gallery mode (WGM) resonators are a powerful and versatile
tool used in many branches of science. Fine tuning of the central frequency and
line width of individual resonances is however desirable in a number of
applications including frequency conversion, optical communications and
efficient light-matter coupling. To this end we present a detailed theoretical
analysis of dielectric tuning of WGMs supported in axisymmetric resonators.
Using the Bethe-Schwinger equation and adopting an angular spectrum field
representation we study the resonance shift and mode broadening of high
WGMs when a planar dielectric substrate is brought close to the resonator.
Particular focus is given to use of a uniaxial substrate with an arbitrarily
aligned optic axis. Competing red and blue resonance shifts ( MHz),
deriving from generation of a near field material polarisation and back action
from the radiation continuum respectively, are found. Anomalous resonance
shifts can hence be observed depending on the substrate material, whereas mode
broadening on the order of MHz can also be simply realised.
Furthermore, polarisation selective coupling with extinction ratios of
can be achieved when the resonator and substrate are of the same composition
and their optic axes are chosen correctly. Double refraction and properties of
out-coupled beams are also discussed
Urban growth drivers in a Europe of sticky people and implicit boundaries
We investigate urban GDP pc growth across the EU12 using data for functionally defined cities - rather than administrative regions. We test hypotheses on the role of human capital, EU integration and fragmentation of urban government and explore spatial dependence and mechanisms of spatial interaction. Results are acceptable on standard econometric tests without measures of spatial interaction but there is spatial dependence. If variables reflecting spatial adjustment are included, they are statistically significant and eliminate spatial dependence. Not only do the results now provide consistent estimates of parameters, they also support relevant theoretical insights and show national borders are still significant barriers to economic adjustment. People in Europe are sticky so it is unreasonable to assume spatial disparities will disappear. Our findings also imply that cities in Europe form national rather than a single continental system
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