Thomas F. George

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Neither flapping and running to take-off nor gliding from heights can be disproved as the assured evolutionary origin of self-powered flight observed in modern vertebrates. Gliding with set wings would utilize available potential energy from gravity but gain little from flapping. Bipedal running, important in avian phylogeny, possibly facilitated the(More)
A theory of linear and nonlinear optical susceptibilites of disordered composites consisting of nanospheres in a dielectric host ͑Maxwell Garnett composites͒ is developed. The theory is based on a spectral representation in the dipole approximation. Numerical computations are performed in the framework of the dipolar spectral theory to obtain the linear(More)
The possibility of compensating absorption in negative-index metatamterials (NIMs) doped by resonant nonlinear-optical centers is shown. The role of quantum interference and extraordinary properties of four-wave parametric amplification of counter-propagating electromagnetic waves in NIMs are discussed. Negative refractive index metamaterials (NIMs) present(More)
Two-and four-point density correlation functions p 2 (r) and p 4 (r) are studied numerically and theoretically in computer-generated three-dimensional lattice cluster-cluster aggregates ͑CCA͒ with the number of particles N up to 20 000 in application to the light scattering problem. The ''pure'' aggregation algorithm is used, where subclusters of all(More)
Based on the theory of the optical properties of fractal clusters, which is an operator-based modification of the coupled-dipole method, an alternate solution is proposed for the problem of adequately describing the evolution of optical spectra of any polydisperse silver colloid with particles falling within the range of most characteristic sizes (5 − 30(More)
Fluctuations in light scattering from a finite ensemble of fractal clusters are studied numerically and theoretically. It is shown that, for a wide range of wavelengths and angles, relative fluctuations in the scattered intensity are very close to 1 and do not depend on the number of monomers N in fractal clusters (whereas they are proportional to 1/ͱN for(More)
1.1 INTRODUCTION Investigation of the optical properties of carbonaceous smoke produced by incomplete combustion of different types of fuels or wild fires has practical importance for many application areas, such as climate research and remote sensing of fires, to name just a few. As the number of references in the end of this chapter attest, very active(More)
In bulk heterojunction polymer solar cells, external photoexcitation results in localized excitons in the polymer chain. After hot exciton formation and subsequent relaxation, the dipole moment drives the electron to partially transfer to extended orbitals from the original localized ones, leading to self-delocalization. Based on the dynamic fluorescence(More)
With the development of experimental techniques, effective injection and transportation of electrons is proven as a way to obtain polymer light-emitting diodes (PLEDs) with high quantum efficiency. This paper reveals a valid mechanism for the enhancement of quantum efficiency in PLEDs. When an external electric field is applied, the interaction between a(More)