345,110 research outputs found
Mecanismo genético da herança de resistência à Stemphylium solani e insensibilidade a sua fitotoxina em algodoeiro.
No full textA mancha preta do algodoeiro causada por Stemphylium solani ocorre em várias regiões produtora de algodão do Brasil, causando severos prejuízos em rendimento especialmente no Estado do Paraná (Mehta, 1998; Lima et al, 1997). O patógeno ataca apenas as folhas e as infecções de maçã e do colmo até agora não foram observadas. Recentemente, Mehta & Brogin (2000), reportaram que S. solani do algodoeiro produziu fitotoxina, ..
Mehta (Ved) : Rajiv Gandhi and Rama' s Kingdom
No full textBullier Antoine J. Mehta (Ved) : Rajiv Gandhi and Rama' s Kingdom. In: Revue française d'histoire d'outre-mer, tome 83, n°311, 2e trimestre 1996. pp. 152-153
Mehta (Ved) : Rajiv Gandhi and Rama' s Kingdom
No full textBullier Antoine J. Mehta (Ved) : Rajiv Gandhi and Rama' s Kingdom. In: Revue française d'histoire d'outre-mer, tome 83, n°311, 2e trimestre 1996. pp. 152-153
[Kishor C. Mehta, undated-2]
No full textUndated negative of Dr. Kishor C. Mehta, Horn Professor in Civil Engineering, standing in front of the Texas Tech Wind Engineering Research Center building
Mehta, Kishor 2014-01-20
No full textThis interview features Kishor Mehta, who discusses how Texas Tech University's reaction to the Lubbock Tornado of 1970 developed into the National Wind Institute
[Kishor C. Mehta, undated-1]
No full textUndated negative of Dr. Kishor C. Mehta, Horn Professor in Civil Engineering, standing in front of the Texas Tech Wind Engineering Research Center building
[Kishor C. Mehta, undated-3]
No full textUndated slide of Dr. Kishor C. Mehta, Horn Professor in Civil Engineering, with a Texas Tech Wind Engineering Research Center display
Nonlinear properties of silicon core optical fibres
No full textSilica optical fibres are renowned for the framework they have set in modern communications systems, sensors, and biotechnology. One particular trend in current research aims to investigate materials with enhanced optical functionality, high optical efficiency, robustness, and a small device footprint. Amongst the many material choices, semiconductors are emerging as a promising route. In this work, optical fibres and semiconductors are elegantly unified to create a hybrid structure with the potential of seamless integration into current fibre infrastructures. Silica capillaries form the fibre templates in which amorphous semiconductor materials such as silicon and/or germanium are impregnated. This thesis will present the first comprehensive description of the fabrication, characterisation, and the implementation of silicon optical fibres for all-optical signal processing. The fibres are fabricated via a novel high pressure chemical deposition procedure. Each fibre is analysed to determine the exact material composition, uniformity, and more importantly the optical quality. Linear and nonlinear optical characterisations are performed experimentally and supported by intensive numerical studies to validate the results.The high nonlinearity of silicon is exploited for all-optical signal processing. Several investigations have been performed to determine key nonlinear coefficients that were previously unknown in these fibres. Nonlinear absorption experiments allowed for the determination of the degenerate and non-degenerate two-photon absorption coefficients, free carrier cross sections, and free carrier lifetimes of a number of silicon fibres. Nonlinear refraction investigations were then used to establish the Kerr nonlinearity. The strength of this parameter allowed for demonstration of strong self-phase and cross-phase modulation effects. With the insight gained in nonlinear absorption and refraction in silicon optical fibres, all-optical amplitude modulation and wavelength switching was demonstrated at ultrafast sub-picosecond speeds
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