Mission report: a strategy to inventory, characterize, and monitor the marine region within and around the National Park and Monument boundaries of St. John, USVI, July 21- July 31, 2008

The intent of this field mission was to continue ongoing efforts: (1) to spatially characterize and monitor the distribution, abundance and size of both reef fishes and conch within and around the waters of the Virgin Islands National Park (VIIS) and newly established Virgin Islands Coral Reef National Monument (VICR), (2) to correlate this information to in-situ data collected on associated habitat parameters, (3) to use this information to establish the knowledge base necessary for enacting management decisions in a spatial setting and to establish the efficacy of those management decisions. This work is supported by the National Park Service and NOAA’s Coral Reef Conservation Program’s Caribbean Coral Reef Ecosystem Monitoring Project. The report highlights the successes of this mission.

A report on the fisheries of Uganda investigated by the Cambridge Expedition to the East African Lakes, 1930-31

There was very little previous information to use as a basis for work on Lakes Edward and George, but fortunately the region had been mapped in some detail by the Uganda-Congo Boundary Commission of 1906-08. This map served as a satisfactory foundation, but the western Congo shoreline of Lake Edward was inserted only by a dotted line, and a number of inaccuracies, particularly with regard to the islands and littoral of L. George, came to light during our survey.

Molecular beam epitaxy growth and photoluminescence study of room temperature 1.31 mu m (InyGa1-yAs/GaAs1-x Sb-x)/ GaAs bilayer quantum wells

Molecular beam epitaxy (MBE) growth of (InyGa1-yAs/GaAs1-xSbx)/GaAs bilayer quantum well (BQW) structures has been investigated. It is evidenced by photo luminescence (PL) that a strong blue shift of the PL peak energy of 47 meV with increasing PL excitation power from 0.63 to 20 mW was observed, indicating type II band alignment of the BQW. The emission wavelength at room temperature from (InyGa1-yAs/GaAs1-xSbx)/GaAs BQW is longer (above 1.2 μ m) than that from InGaAs/GaAs and GaAsSb/GaAs SQW structures (1.1 μ m range), while the emission efficiency from the BQW structures is comparable to that of the SQW. Through optimizing growth conditions, we have obtained room temperature 1.31 μ m wavelength emission from the (InyGa1-yAs/GaAs1-xSbx)/GaAs BQW. Our results have proved experimentally that the GaAs-based bilayer (InyGa1-yAs/GaAs1-xSbx)/GaAs quantum well is a useful structure for the fabrication of near-infrared wavelength optoelectronic devices. © 2005 Elsevier B.V. All rights reserved.

Influence of growth parameters of frequency-radio plasma nitrogen source on extending emission wavelengths from 1.31 mu m to 1.55 mu m GaInNAs/GaAs quantum wells grown by molecular-beam epitaxy

High (42.5%) indium content GaInNAs/GaAs quantum wells with room temperature emission wavelength from 1.3 mu m to 1.5 mu m range were successfully grown by Radio Frequency Plasma Nitrogen source assisted Molecular Beam Epitaxy. The growth parameters of plasma power and N-2 How rate were optimized systematically to improve the material quality. Photoluminescence and transmission electron microscopy measurements showed that the optical and crystal quality of the 1.54 mu m GaInNAs/GaAs QWs was kept as comparable as that in 1.31 mu m.

EXPERIMENTAL INVESTIGATION OF THE STELLAR REACTION S-30(p, gamma)(31) Cl VIA COULOMB DISSOCIATION

The Coulomb dissociation of the proton-rich nuclei Cl-31 was studied experimentally using Cl-31 beams at 58 MeV/nucleon with a lead target. The relative energy between the reaction products, S-30 and proton, was obtained. The first excited state in Cl-31 was observed which is relevant to the resonant capture of stellar S-30(p, gamma)Cl-31 reaction

科尔沁沙地31种1年生植物萌发特性比较研究

在实验室条件下观测了科尔沁沙地乌兰敖都地区 1年生植物当年新采种子的萌发特点。在 3 1种植物中 ,7种植物包括大籽蒿、虎尾草、冠芒草、刺沙蓬、曼陀罗、龙葵、地锦的发芽率超过 80 % ,9种植物包括苍耳、水稗草、狗尾草、虱子草、沙米、灰绿藜、野西瓜苗、太阳花、鹤虱的发芽率不足 10 %。 1～ 3 d开始发芽的 18种植物包括大籽蒿、黄蒿、虎尾草、毛马唐、画眉草、冠芒草、野大豆、黄花草木樨、网果葫芦巴、沙米、雾冰藜、碱地肤、刺沙蓬、苘麻、野西瓜苗、马齿苋、苋菜、地锦。超过 10 d基本不发芽的 5种植物包括苍耳、狗尾草、虱子草、灰绿藜、太阳花。发芽持续期小于 10 d的 12种植物包括毛马唐、水稗草、画眉草、沙米、雾冰藜、苘麻、野西瓜苗、益母草、马齿苋、龙葵、地锦、鹤虱 ;发芽持续期超过 2 1d的 6种植物包括大籽蒿、黄蒿、冠芒草、黄花草木樨、刺沙蓬、碱蓬。高发芽率植物的发芽进程线显示了 3种萌发格局 :速萌型 ,包括虎尾草、地锦、曼陀罗、龙葵 ;缓萌型 ,包括刺沙蓬 ;中间型 ,包括大籽蒿、冠芒草

稀土LD_(31)挤压铝合金氧化着色膜耐磨性能的研究

为进一步应用LD31挤压铝合金，在该合金中加入了稀土元素，并对影响其耐磨性的工艺因素如电流密度、电解液浓度、氧化时间等进行了研究。试验结果表明，适量加入稀土元素可改善LD31铝合金氧化着色膜的耐磨性能。