2,592 research outputs found
Exploring the use of goal proximity by Olympic athletes: A preliminary study
An athlete’s 4-year Olympic preparation cycle requires systematic planning involving the use of short- and long-term goals. These goals provide athletes with increased motivation, persistence, effort and direction in their goal pursuit. Short-term goals can be viewed as steppingstones towards the long-term goals. Therefore, the purpose of this study was to explore the use of short- and long-term goals by Olympic athletes. A qualitative design was used, with semi-structured interviews as the major data source. Participants were purposefully sampled from a typically understudied sports population. Four male Olympians, representing swimming and athletics, shared their experiences about how and why they set and used short- and long-term goals. The athletes spent an average of 11.3 years training and competing at the elite level. Findings revealed that winning a national championship and competing at the Olympic Games were their major long-term goals. Furthermore, these goals did not change during their athletic career. Short-term goals were primarily set to learn, develop and improve their skills/techniques that would allow them to reach their ultimate goals. Major competitive events (e.g. national championships, Pan Am Games, Olympic Games) dictated how they planned these goals. The findings also support previous research suggesting the use of both short and long-term goals. Coaches and young athletes can use the information provided to plan their sports goals. Future research should investigate the goal setting practices of team versus individual sport Olympic athletes
Optimization of the nanolens consisting of coupled metal nanoparticles: An analytical approach
Using a simple and intuitive analytical approach, we perform optimization of a nanolens composed of coupled metal nanoparticles capable of subwavelength focusing of light inside the narrow gap separating the particles. Specifically, we optimize the structure of two nanospheres of different sizes to achieve maximum field enhancement at an off-center position in the gap. We demonstrate that the nanolens of two or more spheres acts simultaneously as an efficient antenna with large dipole and an efficient cavity with small effective volume
Enhancement of light absorption in a quantum well by surface plasmon polariton
We investigate analytically the degree to which the absorption of light in a single quantum well can be enhanced in the proximity of a structured metallic surface and show that the wavelength at which the maximum enhancement of about one order of magnitude is attained depends on metal loss and the initial absorption in a quantum well
Impact of disorder on surface plasmons in two-dimensional arrays of metal nanoparticles
We study the impact of disorder on the properties of surface plasmons (SP) in metal nanoparticle arrays and develop analytical expressions enabling us to ascertain the degree of localization and mixing between the SP states. We show that it might be advantageous to intentionally introduce a certain degree of disorder in order to engineer the improved sensors and detectors
Comparative study of field enhancement between isolated and coupled metal nanoparticles: An analytical approach
We present an analytical model that takes into account the coupling between the surface plasmon modes in complex metal nanostructures. We apply this model to evaluate the field enhancement in the gap of two coupled Au metal spheres embedded in GaN dielectric and compare the result with that obtained by the single sphere. The results show additional improvement can be obtained in the gap depending on the width of the gap. This approach offers a clear physical insight for the enhancement and a straightforward method for optimization
Practicality of compensating the loss in the plasmonic waveguides using semiconductor gain medium
We consider the issue of compensating the loss in plasmonic waveguides with semiconductor gain material and show that, independent of specific geometry, full loss compensation in plasmonic waveguides with significantly sub-wavelength light confinement (less than λ/4n) requires current density well in excess of 100 kA/cm2. This high current density is attributed to the unavoidable shortening of recombination time caused by the Purcell effect inherent to sub-wavelength confinement. Consequently, an injection-pumped plasmonic laser that is truly sub-wavelength in all three dimensions (“spaser”) would have threshold current densities that are hard to obtain in any conceivable semiconductor device
Terahertz gain in a SiGe/Si quantum staircase utilizing the heavy-hole inverted effective mass
Modeling and design studies show that a strain-balanced Si1−xGex/Si superlattice onSi1−yGey-buffered Si can be engineered to give an inverted effective mass HH2 subband adjacent to HH1, thereby enabling a 77 K edge-emitting electrically pumped p–i–pquantum staircase laser for THz emission at energies below the 37 meV Ge–Ge optical phonon energy. Analysis of hole-phonon scattering, lifetimes, matrix elements, and hole populations indicates that a gain of 450 cm−1 will be feasible at f = 7.3 THz during 1.7 kA/cm2 current injection
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