977 research outputs found

    Beam quality improvement of high-power semiconductor lasers using laterally inhomogeneous waveguides

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    This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Appl. Phys. Lett. 113, 221107 (2018) and may be found at https://doi.org/10.1063/1.5054645.High-brightness vertical broad-area edge-emitting (HiBBEE) semiconductor lasers in the 1060 nm wavelength range with excellent beam quality in both lateral and vertical directions are presented. An approach to modify the thresholds of the transverse lateral modes of ridge-waveguide (RW) lasers is investigated. It has been experimentally shown that inhomogeneities in both sides of the ridges increase optical losses of the higher-order lateral modes as compared to the fundamental mode. The resulting enhancement in the contrast of the optical losses favors the emission of the fundamental mode and improves the beam quality. Reference RW HiBBEE lasers with a 15 μm wide conventional ridge and a 2.0 mm long cavity provide laterally multi-lateral mode emission which is typical for RW lasers with such wide and homogeneous ridges. On the other hand, RW HiBBEE lasers with triangular-shaped corrugations in both sides of 15 μm wide ridges provide single-lateral mode emission across a wide current range and improve the lateral M2 factor by more than a factor of 2 in the investigated current range. The corrugated RW HiBBEE lasers provide an almost 2 times higher brightness than the reference RW lasers

    Investigating the basis of sexual dysfunction during late-onset hypogonadism

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    Late-onset hypogonadism (LOH) is the term used to describe the decline in serum testosterone levels associated with increasing age in men above 40 years. A number of symptoms are attributed to LOH, but the most common association is that of sexual dysfunction. LOH has recently come under greater scrutiny with the widespread use of testosterone therapy, and concerns regarding the efficacy and safety of testosterone replacement therapy have been raised. In particular, the cardiovascular safety and the beneficial effects of testosterone replacement therapy on general health have been questioned. This review will give an overview of the current evidence for the relationship of LOH and male sexual dysfunction

    Domestic use of biomass fuel in the rural Meghna floodplain areas of Bangladesh

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    Rural households in the developing countries constitute the largest share of the biomass fuel consumption. It is also a major source of energy in the low income country. However, this energy consumption pattern varies from region to region. Different case studies on the biomass fuel consumption will certainly contribute to the understanding on the energy uses of a nation. The present study was conducted in the rural areas of the Meghna floodplain zone in Bangladesh, with a total of 80 sampled households, using the stratified random sampling technique through the semi-structured questionnaires from November 2008 through February 2009. Firewood, cowdung, leaves and twigs, branches, rice straw and rice husk were used as the biomass fuels mainly for the cooking purpose. Leaves and twigs were found as the dominant biomass fuel as 187 +/- 25.69 (SE) kg month(-1) household(-1). The major source of biomass fuel collection was identified as the own homestead and agricultural lands, 74%. The households spent 14.56 +/- 8.94 US$ month(-1) household(-1) for biomass fuels. The ratio of the total energy expenditure to the total income of the household was around 11%. But, the ratio of the biomass expenditure to the total energy expenditure of the households was 68%. Monthly income, land ownership and family size were found significantly influencing to the biomass energy expenditure. The study will be useful for the policy makers in the renewable energy, forestry and agriculture sector in Bangladesh.ArticleIFOREST-BIOGEOSCIENCES AND FORESTRY. 3:144-149 (2010)journal articl

    Investment in fish seed multiplication farms in Bangladesh: Evidences of an attractive business

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    This study mainly evaluated the profitability of Fish Seed Multiplication Farms (FSMFs) having hatchery, nursery and hatchery-cum-nursery located in the districts of Jessore, Jhenidah and Narail in Bangladesh. The general findings of the study were that the investment in FSMFs with hatchery, nursery and hatchery-cum-nursery was highly profitable business. The results clearly indicated that the investment on hatchery was the most profitable than those of nursery and hatchery-cum-nursery operations from the viewpoints of individual investors. The results of sensitivity analysis suggested that the investment in nursery farm was a risky business with 20 per cent increase in operation and management as well was production costs or 20 per cent reduction in benefits if other things remaining the same. It was also evident from the study that the investors of FSMFs had currently been facing some crucial problems, which among others are: problems of inbreeding, shortage of brood fish, incidence of diseases, unavailability of certain inputs and lack of credit
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