巢湖渔业资源现状及其对水体富营养化的响应研究

2002年至2004年期间,对巢湖鱼类资源进行调查,共发现鱼类54种,隶属16科、9目,主要以鲤科鱼类为主(35种),占64.8%,与20世纪80年代相比,鱼类种类数减少了40种,主要表现在洄游性种类急剧减少,甚至消失。渔业资源结构(渔获物)表现为以湖鲚、太湖新银鱼等小型鱼类为优势种类,在渔产量的比例不断上升,而大型鱼类(如翘嘴、鲤等)的种群结构趋于低龄化,产量呈下降趋势。结合已有的历史资料,分析巢湖渔业资源变化的影响因素,结果表明造成巢湖渔业资源结构变化受人为活动的影响主要表现在水利工程修建、过度捕捞和

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.

气泡/液滴Marangoni迁移数值模拟研究

本文利用Level Set方法,数值模拟了微重力情况下气泡/液滴的Marangoni迁移现象,分析了Marangoni数对迁移速度的影响.数值模拟结果表明,随着Marangoni数的增大,非线性热对流效应的影响会逐渐增大,导致沿相界面温度分布趋于均匀,从而降低迁移运动的驱动力,使气泡/液滴的迁移速度随Marangoni数的增加而逐渐减小.

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。

稀土LD_(31)挤压合金氧化着色膜耐磨性能的研究

在硫酸溶液中进行的阳极氧化,是铝材表面处理常用的一种工艺,得到的阳极氧化膜具有硬度高、耐磨性高、抗蚀性好等特点。目前国内外仍采用显微硬度计在膜的表面打压痕,以压痕大小来确定膜层硬度,然而硬度试验一般只限于少数经过特殊处理的硬质阳极氧化膜,而对于通常所见普通氧化膜不宜作硬度测定。普通氧化膜

Permanent Genetic Resources added to Molecular Ecology Resources Database 1 May 2009-31 July 2009

This article documents the addition of 512 microsatellite marker loci and nine pairs of Single Nucleotide Polymorphism (SNP) sequencing primers to the Molecular Ecology Resources Database. Loci were developed for the following species: Alcippe morrisonia morrisonia, Bashania fangiana, Bashania fargesii, Chaetodon vagabundus, Colletes floralis, Coluber constrictor flaviventris, Coptotermes gestroi, Crotophaga major, Cyprinella lutrensis, Danaus plexippus, Fagus grandifolia, Falco tinnunculus, Fletcherimyia fletcheri, Hydrilla verticillata, Laterallus jamaicensis coturniculus, Leavenworthia alabamica, Marmosops incanus, Miichthys miiuy, Nasua nasua, Noturus exilis, Odontesthes bonariensis, Quadrula fragosa, Pinctada maxima, Pseudaletia separata, Pseudoperonospora cubensis, Podocarpus elatus, Portunus trituberculatus, Rhagoletis cerasi, Rhinella schneideri, Sarracenia alata, Skeletonema marinoi, Sminthurus viridis, Syngnathus abaster, Uroteuthis (Photololigo) chinensis, Verticillium dahliae, Wasmannia auropunctata, and Zygochlamys patagonica. These loci were cross-tested on the following species: Chaetodon baronessa, Falco columbarius, Falco eleonorae, Falco naumanni, Falco peregrinus, Falco subbuteo, Didelphis aurita, Gracilinanus microtarsus, Marmosops paulensis, Monodelphis Americana, Odontesthes hatcheri, Podocarpus grayi, Podocarpus lawrencei, Podocarpus smithii, Portunus pelagicus, Syngnathus acus, Syngnathus typhle,Uroteuthis (Photololigo) edulis, Uroteuthis (Photololigo) duvauceli and Verticillium albo-atrum. This article also documents the addition of nine sequencing primer pairs and sixteen allele specific primers or probes for Oncorhynchus mykiss and Oncorhynchus tshawytscha; these primers and assays were cross-tested in both species.