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.

无量山西黑冠长臂猿二重唱的声谱结构和时间特征

2003年3月-2004年3月对无量山大寨子3群西黑冠长臂猿的二重唱的时间特征进行了监测。于2007年3月和2008年3月利用Sony TC-D5Pro2录音机、Sony C-76指向性话筒和Sony录音磁带对其二重唱进行了录音,对录音效果最好的5个声音用Signal/RTS4.0软件进行声谱分析。对无量山西黑冠长臂猿二重唱的声谱结构和时间特征的研究结果表明,雄性西黑冠长臂猿的声音由起始音节、简单的重复音节和调节音节组成。根据频率变化的强度,可以将调节音节分为弱调节音节和强调节音节。强调节音节的特征是第二个音节具有非常明显的频率变化,有时第三个音节有类似变化,变频时的最高频率可达到5828Hz。雌性长臂猿一般只会发出一种类型的声音,即固定而刻板的激动鸣叫。根据激动鸣叫是否完整可以分为成功的激动鸣叫和失败的激动鸣叫。典型的西黑冠长臂猿二重唱通常由成年雄性发起,并占主导地位,且一般由雄性结束。雌性激动鸣叫结束后,雄性马上发出调节音节与之配合,雄性调节音节与雌性激动鸣叫的时间间隔平均为2.7s。平均每个群体的鸣叫频次为53%。如果发生鸣叫,一个群体平均每天鸣叫1.09次。91.5%的鸣叫发生在日出前0.5h至日出后...

小鼠Bicc1基因RNAi序列的筛选与鉴定

通过网上提供的生物信息学分析软件进行搜索和比对,初步筛选到3个较好的针对小鼠双尾-C(Bicc1)基因的RNA干扰(RNAi)序列。合成这3个干涉序列片段后克隆到pRS-HushshRNA载体中。构建Bicc1基因的真核表达载体pEGFP-C3-Bicc1,将绿色荧光蛋白(GFP)标签标记在Bicc1蛋白上。利用细胞转染技术将pEGFP-C3-Bicc1与3个干涉序列载体共转染至体外培养的HEK-293细胞中,最后通过细胞荧光强度、半定量PCR和Westernblotting鉴定出其中两个序列(pRS-Hush-RNAi-Bicc1-N/-C)能明显降低Bicc1蛋白在HEK-293细胞中的表达水平,为下一步建立起低表达Bicc1的稳定细胞株和研究小鼠Bicc1的功能提供了良好的材料。

Acoustic Observation of the Spawning Aggregation of Megalobrama hoffmanni in the Pearl River

Using the Simrad EY60 split-beam echosounder, the spawning aggregation of Megalobrama hoffmanni was observed at the Luopang spawning grounds in the Pearl River, China, from April 19 to 22 2006. With the boat anchored, the transducer was stationary and was aimed horizontally to monitor the migration of the fish. Using fishery information, the echoes of M. hoffmanni were identified. The results showed that the spawning aggregation of M. hoffmanni at Luopang was obvious and easy to discriminate. The target strength of M hoffmanni in situ ranged from -33.8 dB to -52.3 dB (average 42.2dB). The aggregation of M. hoffmanni was obviously affected by light. With a speed of -0.31 m/s, 88.9% of the spawning stocks migrated upstream. Most M hoffmanni were recorded moving near the bottom. Their distinctive acoustic signature demonstrated the suitability of the stationary acoustic observation for M. hoffmanni identification and discrimination.

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.

黄土高原长期种植苜蓿对土壤硫、钙、镁的影响

以22年定位试验为基础,研究黄土高原长期种植紫花苜蓿(Medicago sativaL.)情况下土壤硫、钙、镁组分的变化。结果表明:长期施P使苜蓿连作耕层土壤总硫、有效硫、水溶性硫、吸附性硫、HCl可溶性硫、总无机硫和有机硫含量分别增加9.41%、62.41%、47.51%、30.07%、2.25%、5.38%和17.54%;长期施NPM使苜蓿连作耕层土壤总硫、有效硫、水溶性硫、吸附性硫、HCl可溶性硫、总无机硫和有机硫含量分别增加20.89%、98.31%、68.44%、57.34%、8.07%、12.54%和37.69%。长期施P使苜蓿连作耕层土壤全钙、有效钙、水溶态钙、交换态钙和酸溶态钙含量增加分别增加4.64%、4.27%、11.66%、4.05%和8.59%,但残余态钙含量降低2.21%;长期施NPM使苜蓿连作耕层土壤全钙、有效钙、水溶态钙、交换态钙和酸溶态钙含量增加分别增加8.69%、8.30%、51.59%、6.73%和27.77%,但残余态钙含量降低26.23%。长期施NPM使苜蓿连作耕层土壤全镁、有效镁、水溶态镁、交换态镁、酸溶态镁和残余态镁含量分别增加7.38%、61.98%、63.16%...

3μm GaInNAs/GasAs Quantum Well Resonant Cavity Enhanced Photodetector

A 1.3μm GaInNAs resonant cavity enhanced (RCE) photodetector (PD) has been grown by molecular beam epitaxy (MBE) monolithically on (100) GaAs substrate using a home-made ion-removed dc-plasma cell as nitrogen source. A transfer matrix method was used to optimize the device structure. The absorption region is composed of three GaInNAs quantum wells separated by GaAs layers. Devices were isolated by etching 130μm-diameter mesas and filling polyamide into grooves. The maximal quantum efficiency of the device is about 12% at 1.293μm. Full width at half maximum (FWHM) is 5.8nm and 3dB bandwidth is 304MHz. Dark current is 2 * 10~(-11) A at zero bias voltage. Further improvement of the performance of the RCE PD can be obtained by optimizing of the structure design and MBE growth conditions.

Isotopic dependence of production cross sections of superheavy nuclei in hot fusion reactions

The dinuclear system model has been further developed by introducing the barrier distribution function method in the process of heavy-ion capture and fusion to synthesize superheavy nuclei. The capture of two colliding nuclei, formation and de-excitation process of compound nucleus are decribed by using empirical coupled channel model, solving master equation numerically and statistical evaporation model, respectively. Within the framework of the dinuclear system model, the fusion-evaporation excitation functions of the systems Ca-48(Am-243, 3n-5n) (288-286)115 and Ca-48(Cm-248, 3n-5n)(293-291)116 are calculated, which are used for synthesizing new superheavy nuclei at Dubna in recent years. Isotopic dependence of production cross sections with double magic nucleus Ca-48 bombarding actinide targets U, Np, Pu, Am, Cm to synthesize superheavy nuclei with charged numbers Z=112-116 is analyzed systematically. Based on these analysis, the optimal projectile-target combination and the optimal excitation energy are proposed. It is shown that shell correction energy and neutron separation energy will play an important role on the isotopic dependence of production cross sections of superheavy nuclei.

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