Mode division multiplexing over 2km of OM2 fibre using rotationally optimized mode excitation with fibre coupler demultiplexer

A Spatial Light Modulator and a non-specialized multimode coupler are used together to provide sufficient channel isolation and modal bandwidth for 2x12.5Gbps NRZ over 2km of standard graded-index multimode fibre without DSP. © 2012 IEEE.

牛山湖浮游生物群落DNA指纹结构与理化因子的关系

对牛山湖5个站点的浮游生物群落DNA多态性进行了RAPD指纹和PCR-DGGE指纹分析,并探讨了其与理化因子的关系.结果如下:1)从40条随机引物中筛选出9条引物,共获得93条谱带,多态率为58%;各站点所得谱带平均为67条,其中Ⅰ站最少,为61条,Ⅴ站最多,为74条;2)PCR-DGGE指纹图谱共含102条谱带,其中原核生物56条,真核生物46条,谱带总数以Ⅲ站、Ⅳ站和Ⅴ站较多,Ⅰ站和Ⅱ站较少;3)Ⅱ站的总磷、叶绿素、化学耗氧量、硬度及电导率最高;各站点间溶氧和pH差异较小.相似性聚类分析表明,浮游生物

三峡库区藻类种群结构与密度变化及其与氮磷浓度的相关性分析

2003年1月~2004年12月对三峡湖北库区江段5个采样点及其一级支流——香溪河流域6个采样点的浮游藻类进行了为期2周年的调查,共采集和鉴定浮游藻类定性和定量水样1 000余个,获得有效数据2 000多个。数据显示,蓄水前(2003年1月~2003年6月)、蓄水1周年(2003年6月~2004年5月)和蓄水1.5年(2004年6月~2004年12月)3个时间段之间,被调查水域的浮游藻类群落结构、细胞密度和水质状况均存在一定的差异。总体而言,藻类的群落结构干流江段以硅藻为主,绿藻次之;支流水域以绿藻占据首

稀有鮈鲫血液学指标的研究

江西省自然科学基金(0130004); 中国科学院知识创新工程重要方向项目(KSCX-SW-125)资助

Large-eddy simulation of complex geometry jets

Computations are made for chevron and coflowing jet nozzles. The latter has a bypass ratio of 6:1. Also, unlike the chevron nozzle, the core flow is heated, making the inlet conditions reminiscent of those for a real engine. A large-eddy resolving approach is used with circa 12 × 10 6 cell meshes. Because the codes being used tend toward being dissipative the subgrid scale model is abandoned, giving what can be termed numerical large-eddy simulation. To overcome near-wall modeling problems a hybrid numerical large-eddy simulation-Reynolds-averaged Navier-Stokes related method is used. For y + ≤ 60 a Reynolds-averaged Navier-Stokes model is used. Blending between the two regions makes use of the differential Hamilton-Jabobi equation, an extension of the eikonal equation. For both nozzles, results show encouraging agreement with measurements of other workers. The eikonal equation is also used for ray tracing to explore the effect of the mean flow on acoustic ray trajectories, thus yielding a coherent solution strategy. © 2011 by Cambridge University.

饮用水中浮游藻类标本制作方法

目的 研究饮用水中藻类形态学鉴定样品标本制作方法。方法 分别对不同水源供水区末梢水和同一地点水箱水采样,进行藻类形态学检测。结果城市末梢水中浮游藻类检出率为89％;饮水水箱水中浮游藻类检出率为60％,并且观察到水箱水藻类在种属和数量上增加的情况。结论 该样品标本制作方法完全可以用于饮用水藻类形态学研究。

Raman spectroscopy as a versatile tool for studying the properties of graphene.

Raman spectroscopy is an integral part of graphene research. It is used to determine the number and orientation of layers, the quality and types of edge, and the effects of perturbations, such as electric and magnetic fields, strain, doping, disorder and functional groups. This, in turn, provides insight into all sp(2)-bonded carbon allotropes, because graphene is their fundamental building block. Here we review the state of the art, future directions and open questions in Raman spectroscopy of graphene. We describe essential physical processes whose importance has only recently been recognized, such as the various types of resonance at play, and the role of quantum interference. We update all basic concepts and notations, and propose a terminology that is able to describe any result in literature. We finally highlight the potential of Raman spectroscopy for layered materials other than graphene.

中国缓步动物门二新种及三新纪录种和亚种(异缓步纲,棘影熊虫科;真缓步纲,小斑熊虫科,大生熊虫科,高生熊虫科)

记述采自河南省洛阳市、湖北省京山县和四川省都江堰市的缓步动物门 2新种及 3新纪录种和亚种 :异缓步纲棘影熊虫科的四棘棘影熊虫 ,新纪录EchiniscusquadrispinosusRichters,190 2 ;真缓步纲小斑熊虫科的都江小斑熊虫 ,新种Milnesiumdujiangensissp .nov .,大生熊虫科的节值大生熊虫戴冠亚种 ,新纪录MacrobiotusharmsworthicoronatusBarros,1942 ;高生熊虫科的大指等高熊虫 ,新纪录Isohypsibiusma

亚热带水体营养状态定量评价及预测研究

采用相关加权营养状态指数法对H水库营养状态进行连续的数值化分级评价 ,准确反映了该水库的营养状态发展阶段和富营养化发展过程 ,克服了固定参数值评价湖泊、水库营养状态的局限性和重叠现象。根据湖泊外力函数 (主要是外来性营养盐浓度或负荷 )与湖内营养状态响应间的定量关系及OECD国际合作组织研究成果 ,提出了H水库营养盐输入负荷与库中磷浓度响应关系数学模型 ,确定了在水体功能改变后 ,其磷允许负荷量及控制标准 ,结果与实际相符

小鞘指环虫种群的季节动态

作者在1992—1994年期间对鲢指环虫病病原小鞘指环虫种群的季节动态进行了研究。小鞘指环虫种群从每年的冬季开始出现，到次年春末（4月），其感染率与丰度均发展至高峰。此后丰度随着水温的上升而迅速下降，到6月上旬，种群消失。在感染强度低于200虫／鱼的情况下，小鞘指环虫对宿主的肥满度没有显著的影响。

Nonlinear analysis of cardiac rhythm fluctuations using DFA method

An approach by which the detrented fluctuation analysis (DFA) method can be used to help diagnose heart failure was demonstrated. DFA was applied to patients suffering from congestive heart failure (CHF) to check correlations between DFA indices and CHF, and determine a correlation between DFA indices and mortality, with a particular attention to the residue parameter, which is a measure of the departure of the DFA from its power law approximation. DFA parameters proved to be useful as a complement to the physiological parameters weber and FE to sort out the patients into three prognostic group.

鱼腥藻提取液对水稻生长发育和产量的促进作用

以田间小区试验和大区产量直接对比的方法研究了鱼腥藻提取液对水稻幼苗生长和产量以及产量构成要素的影响，并探讨了方便有效且适宜于大田使用的方法。用藻液处理后水稻幼苗增高，根数、根长增加，分蘖能力增强，秧龄提前，叶面积明显加大。水稻成熟后除株高比对照略有下降外，各项产量构成要素如粒数、粒重、有效分蘖数、植株干重、千粒重、穗长等都优于对照组，但增产幅度随水稻品种和处理方式不同而异。大田使用时以1％鱼腥藻提取液浸种并在二叶一心时进行叶面喷施效果为好。

Microheterogeneous Thoria-Urania Fuels for Pressurized Water Reactors

A thorium-based fuel cycle for light water reactors will reduce the plutonium generation rate and enhance the proliferation resistance of the spent fuel. However, priming the thorium cycle with ²³⁵U is necessary, and the ²³⁵U fraction in the uranium must be limited to below 20% to minimize proliferation concerns. Thus, a once-through thorium-uranium dioxide (ThO2-UO2) fuel cycle of no less than 25% uranium becomes necessary for normal pressurized water reactor (PWR) operating cycle lengths. Spatial separation of the uranium and thorium parts of the fuel can improve the achievable burnup of the thorium-uranium fuel designs through more effective breeding of ²³³U from the ²³²Th. Focus is on microheterogeneous fuel designs for PWRs, where the spatial separation of the uranium and thorium is on the order of a few millimetres to a few centimetres, including duplex pellet, axially microheterogeneous fuel, and a checkerboard of uranium and thorium pins. A special effort was made to understand the underlying reactor physics mechanisms responsible for enhancing the achievable burnup at spatial separation of the two fuels. The neutron spectral shift was identified as the primary reason for the enhancement of burnup capabilities. Mutual resonance shielding of uranium and thorium is also a factor; however, it is small in magnitude. It is shown that the microheterogeneous fuel can achieve higher burnups, by up to 15%, than the reference all-uranium fuel. However, denaturing of the ²³³U in the thorium portion of the fuel with small amounts of uranium significantly impairs this enhancement. The denaturing is also necessary to meet conventional PWR thermal limits by improving the power share of the thorium region at the beginning of fuel irradiation. Meeting thermal-hydraulic design requirements by some of the microheterogeneous fuels while still meeting or exceeding the burnup of the all-uranium case is shown to be potentially feasible. However, the large power imbalance between the uranium and thorium regions creates several design challenges, such as higher fission gas release and cladding temperature gradients. A reduction of plutonium generation by a factor of 3 in comparison with all-uranium PWR fuel using the same initial ²³⁵U content was estimated. In contrast to homogeneously mixed U-Th fuel, microheterogeneous fuel has a potential for economic performance comparable to the all-UO2 fuel provided that the microheterogeneous fuel incremental manufacturing costs are negligibly small.