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G García-Bermúdez H Somacal MA Cardona A Filevich E Achterberg L Szybisz 《Canadian Metallurgical Quarterly》1995,51(3):1181-1191
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DNA double-strand breaks are very genotoxic lesions that can result in chromosome aberrations. The current view is that DNA double-strand breaks are repaired most efficiently through homologous recombination in yeast and simple end-joining in mammalian cells. However, recent experiments reveal that both repair pathways are conserved from yeast to mammals, including humans. The challenge ahead is to put the different pieces of the jigsaw together into coherent mechanisms for both pathways and to determine their relative contributions to ionizing-radiation resistance and to the prevention of genetic instability and carcinogenesis. 相似文献
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Joaquín Cortés Eliana Valencia Gonzalo Aguila Esteban Orellana Paulo Araya 《Catalysis Letters》2008,126(1-2):63-71
An experimental study is made of the time decay of activity of the CO–NO reaction on a Pd/Al2O3 looking at the effect on reaction order and apparent activation energy. The optimum kinetics parameters fitting the steady state data at moderate pressures are determined. The time decay curves are analyzed through various catalyst deactivation models. 相似文献
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Diffractive optical elements have a large number of industrial applications, such as beam shaping and optical filtering. Traditionally, these elements modulate the phase of the incoming light or its amplitude, but not both. To overcome this limitation, full complex-amplitude modulation diffractive optical elements were developed. Well-established integrated circuit fabrication steps were employed to fabricate the devices with high precision. Using this approach, the new element‘s optical performances are improved also for near field operations. With this device it is possible to obtain 100% efficient spatial filtering and low noise reconstructed images. 相似文献
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Merino Gonzalez J.L. Ortiz Saenz F. Valencia Miranda G. 《Solid-State Circuits, IEEE Journal of》1991,26(9):1270-1277
The shumbler (shuffler/scrambler) is a circuit designed and fabricated to form part of a broadband customer premises network. The circuit is implemented in 1.2-μm BiCMOS double-metal technology. The circuit is bidirectional, and can perform the functions of scrambling and shuffling or descrambling and unshuffling by means of control signals to three integrated multiplexers. The shumbler also includes a programmable multiplexer that allows the selection of one out of the 16 output channels of the shuffler through a serial output for local system test purposes. The shumbler circuit interfaces emitter-coupled-logic (ECL) and transistor-transistor-logic (TTL) logic levels using a single power supply of -5 V, dissipating 1.5 W, and encapsulated in a 68-pin LCC package with a flat heat spreader which ensures a thermal resistivity of about 10°C/W 相似文献