中国盘肠溞属三新种(甲壳纲:双甲目:盘肠溞科)

本文绘图描述了中国枝角类盘肠溞科盘肠溞属的三个新种:1.腹针盘肠溞Chydorus aciculaius sp.nov.的主要特征为壳瓣腹缘中部有一向后的针刺;2.多刺盘肠溞Chydorus spinosus sp.nov.的主要特征为整个壳瓣表面密布细刺;3.断壳盘肠溞Chydorus mutilatus sp.nov.的主要特征为壳瓣背缘后部平截内陷,有如断缺。

武汉东湖颗粒有机碎屑现存量的测定

对武汉东湖三个采样点的颗粒有机碎屑现存量进行了测定,三个站的平均量(以dmm~3/l表示)分别为72,505、18,125和52,398,其现存量与湖水的pH值无关;与水温有一定的正相关,但这种关系是间接的。

Phylogeography of the freshwater catfish Hemibagrus guttatus (Siluriformes, Bagridae): Implications for South China biogeography and influence of sea-level changes

National Natural Science Foundation of China (NSFC) ; [2007CB411600]; [30530120]

1.55-mu m resonant cavity enhanced photodiode based on MBE grown Ge quantum dots

Self-assembly Ge quantum dots (QD) on Si and Si/Ge mutli-quantum-wells (MQW) are grown by MBE. The island size and island density was investigated by atomics force microscopy. Ten-layer and twenty-layer MQW were selected for photodiode device fabrication. In photoluminescence (PL), a broad peak around 1.55-mu m wavelength was observed with higher peak intensity for the 10-layer MQW which had less defects than the 20-layer sample. Resonant cavity enhanced (RCE) photodiodes were fabricated by bonding on a SOI wafer. Selected responsivity at 1.55 mu m was successfully demonstrated. (c) 2005 Elsevier B.V. All rights reserved.

Simple method for estimating minimum bend radii of SOI single mode curved rib waveguides

A simple method based on the effective index method was used to estimate the minimum bend radii of curved SOI waveguides. An analytical formula was obtained to estimate the minimum radius of curvature at which the mode becomes cut off due to the side radiative loss.

Compact 3-dB tapered multimode interference coupler in silicon-on-insulator

We have fabricated a compact 3-dB multimode interference coupler with a large silicon-on-insulator cross section. To reduce the length of the usual symmetric interference multimode interference coupler, we propose using a parabolically tapered structure. The length of the device is 398 mum. The device has a uniformity of 0.28 dB. (C) 2001 Optical Society of America.

1.55-mu m resonant cavity enhanced photodiode based on MBE grown Ge quantum dots

Self-assembly Ge quantum dots (QD) on Si and Si/Ge mutli-quantum-wells (MQW) are grown by MBE. The island size and island density was investigated by atomics force microscopy. Ten-layer and twenty-layer MQW were selected for photodiode device fabrication. In photoluminescence (PL), a broad peak around 1.55-mu m wavelength was observed with higher peak intensity for the 10-layer MQW which had less defects than the 20-layer sample. Resonant cavity enhanced (RCE) photodiodes were fabricated by bonding on a SOI wafer. Selected responsivity at 1.55 mu m was successfully demonstrated. (c) 2005 Elsevier B.V. All rights reserved.

多媒体节目时序描述的组合技术

组合性是形式描述研究的基本问题 ,便于大型程序的设计、分析、测试和复用 .为了方便用户编制大型多媒体系统的时序描述 ,组合模型是必须的 .目前 ,这样的模型有基于语言的、基于图形的、基于时间区间的和面向对象的等等 .但是 ,这些模型描述层次过低 ,很难支持两个多媒体节目之间的时序描述 .通过引入单位流的概念和扩展两种时序关系 ,研究一种多媒体节目时序描述的结构化技术 ,使复杂的多媒体节目易于理解 ,以方便用户运用组合方法把一些可以复用于不同多媒体节目的节目模块进行组合设计 .

基于动态抢占阈值的实时调度

具有抢占阈值的调度算法集非抢占调度和纯抢占调度的特点 ,既减少了由于过多的随意抢占造成的CPU资源浪费 ,又保证了一定的任务截止期错失率及CPU资源利用率 已有的工作基本集中于讨论任务集完全给定 ,任务数、任务的优先级及任务的抢占阈值在调度前已完全确定 ,而且要求不同的任务具有不同的优先级 提出的具有抢占阈值的调度算法 ,完全放松了对这些条件的限制 ,即任务的个数不确定 ,任务的优先级及其抢占阈值在调度过程中可以动态地变化 最后以常用的LSF调度策略为例 ,结合动态的抢占阈值进行仿真 仿真结果表明 ,对于不确定的任务集、任务优先级和抢占阈值 ,利用具有抢占阈值的动态调度算法 ,降低了任务截止期错失率、提高了CPU的有效使用率

枣芽象甲的综合防治

近年来红枣发展迅速,陕西、山西黄河沿岸红枣栽培面积达30万hm2。随着红枣栽培面积扩大,枣芽象甲(Scythropus yasumatsui)在陕西省佳县和山西省柳林县、稷山县等地危害严重。枣芽象甲属鞘翅目象甲科,又名食芽象甲、枣飞象、枣月象、小灰象甲等,分布于陕西、山西、河南、河北、山东、辽宁等地,危害红枣、苹果、核桃等多种果树。枣芽象甲成虫早春上树危害嫩芽、幼叶,严重时可将枣树嫩芽吃光,造成二次萌芽,削弱树势,推迟生育,严重降低红枣产量和品质。1形态特征枣芽象甲一生经过卵、幼虫、蛹、成虫四种形态。成虫:雄虫体长4.5~5.5mm,深灰色。雌虫体长约4.3~5.5mm,土灰色。头管粗短,末端宽,背面两复眼之间凹陷,前胸背面中间色较深,呈棕灰色。鞘翅弧形,每侧各有细纵沟10条,两沟之间有黑色鳞毛,鞘翅背面有模糊的褐色晕斑。腹面银灰色。卵:长椭圆形,堆生,初产时乳白色,后变棕色。幼虫:乳白色,体长5mm,略弯曲,无足。蛹:4.0~5.0mm,纺锤形,初乳白色,近羽化时红褐色。2生活习性1a(年)发生1代,以幼虫在土壤中越冬。春季3月下旬至4月上旬化蛹,蛹期12~15d(天)。4月中下旬当枣树萌芽时成虫出土,群集...