995 resultados para 55-433
Resumo:
We report an InGaAsP/InP MQW phase modulator operating over the entire 1.55μm fiber band with high phase modulation efficiency and low loss modulation. The spectral dependence of the electro-refraction in a MQW structure is measured for the first time.
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We experimentally demonstrate for the first time 1.55μm vertical-cavity surface-emitting laser (VCSEL) transmission over 6.5 km single mode fiber (SMF) at 20 Gb/s for optical access networks. Characterization of the device is also investigated. © 2009 IEEE.
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The communication deals with the results of comparative tests conducted from Cochin base to study the effect of a tickler chain on the catches landed by a 55' shrimp otter trawl. The net was operated with and without chain and 82 hauls of 61 hours and 28 minutes total duration were made. The following are the conclusions: (a) the catch of shrimp per hour of trawling is increased by about 71% due to attachment of the chain to the ground rope; (b) the attachment of the tickler chain also increased the catch of fish by 25%. The increase in the catch of shrimps and fish is probably due to the disturbance caused by moving chain attached to the foot-rope.
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This is a resume of a 1953-1955 study of Ceylon's fishing gears, fisheries and records of experimental and commercial fishing operations. Representative catches of edible fish per unit of effort for several of the gears studied are summarized in the table. They are low compared with many countries, indicating low abundance of fish.
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The annual report present activities carried out by the different organizations that make up the East African Agricultural & Fisheries Research Council which included: 1. Report of the East African Agriculture & Forestry Research Organization 2. Report of the East African Veterinary Research Organization 3. Report of the East African Fishery Research Organization 4. Report of the East African Marine Fisheries Research Organization The activities reported are for the period 1954-55.
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1993—1994年在保安湖主体湖区开展围圈养殖草鱼对浮游生物多样性影响的研究,包括围圈内外浮游动物种类组成、密度、生物量和多样性指数的季节变化等。分析表明,围圈内共有常见浮游动物64种,围圈外共有常见浮游动物55种。围圈内外浮游动物的年平均密度分别为3738和3196ind/L,年平均生物量分别为0.8177和0.8135mg/L,年平均多样性指数分别为3.3808和2.9717。研究结果表明:围圈养殖草食性鱼类对浮游动物现存量以及多样性指数无显著影响.
Resumo:
Significant reduction of the bulk resistivity in a ferroelectric Pb(Zr 0.45Ti0.55)O3 thin film is observed before the remnant polarization started to decrease noticeably at the onset of its fatigue switching process. It is associated with the increase of charge carriers within the central bulk region of the film. The decrease of bulk resistivity would result in the increase of Joule heating effect, improving the temperature of the thin film, which is evaluated by the heat conduction analysis. The Joule heating effect in turn accelerates the polarization reduction, i.e. fatigue. Enhancing the heat dissipation of a ferroelectric capacitor is shown to be able to improve the device's fatigue endurance effectively. © 2013 Chinese Physical Society and IOP Publishing Ltd.