Flood Routing Models in Confluent and Dividing Channels

By introducing a water depth connecting formula, the hydraulic equations in the dividing channel system were coupled and the relation of discharge distribution between the branches of the dividing channels can be yielded. In this manner, a numerical model for the confluent channels was established to study the variation of backwater effects with the parameters in the channel junction. The meeting of flood peaks in the mainstream and tributary can be analyzed with this model. The flood peak meeting is found to be a major factor for the extremely high water level in the mainstream during the 1998 Yangtze River flood. Subsequently the variations of discharge distribution and water level with channel parameters between each branch in this system were studied as well. As a result, flood evolution caused by Jingjiang River shortcut and sediment deposition in the entrance of dividing channels of the Yangtze River may be qualitatively elucidated. It is suggested to be an effective measure for flood mitigation to enhance regulation capability of reservoirs available upstream of the tributaries and harness branch entrance channels.

相似准则数值优化方法及其应用

提出了复杂流动相似准则的数值优化方法,即通过敏感性分析,从众多无量纲参数中筛选控制流动的主要相似参数.给出了敏感因子的定义,讨论了敏感因子与无量纲量间的依赖关系.并利用该方法对油藏渗流的相似准则进行研究,与理论分析进行对比,得到完全一致的结论.进一步对模型与原型压力分布的误差进行了合理的解释.最后分析了流动参数对敏感因子的影响,发现复杂流动的主要相似准则可能随实际流动参数的不同而变化.

基于孔径耦合带状线的激光脉冲整形系统

实现了一种新型的激光脉冲整形系统，该系统使用了一个由孔径耦合带状线（ACSL）电脉冲整形器驱动的电光调制器。一个电脉冲整形器由两条通过其公共接地板上的耦合孔径发生耦合作用的带状传输线所组成的四端口装置。更换具有不同耦合孔径的公共接地板，该电脉冲整形发生器可以具有150ps时间结构的任意整形电脉冲。将任意整形的电脉冲输入到电光调制器上，就可以得到任意整形的激光脉冲。利用该系统，激光脉冲整形系统能够产生具有150ps前后沿，1～3ns脉冲宽度可调、高对比度、光滑过渡以及任意整形的激光脉冲。

Broadband amplification and upconversion luminescence properties of Er3+/Yb3+ co-doped fluorophosphate glass

Broadband and upconversion properties were studied in Er3+/Yb3+ co-doped fluorophosphate glasses. Large Omega(6) and S-ed/(S-ed + S-md) values and the flat gain profile over 1530-1585 nm indicate the good broadband properties of the glass system. And a premise of using Omega(6) as a parameter to estimate the broadband properties of the glasses is proposed for the first time to our knowledge. Results showed that fluorescence intensity, upconversion luminescence intensity, the intensity ratio of red/green light (656 nm/545 nm) are closely related to the Yb3+:Er3+ ratio and Er3+ concentration, and the corresponding calculated lifetime of F-4(9/2) and S-4(3/2) states for red and green upconversion samples proves this conclusion. The upconversion mechanism is also discussed. (c) 2005 Elsevier Ltd. All rights reserved.

狭叶沙参复合体（桔梗科沙参属）的物种生物学研究

此复合体原先方7个种，1983年被处理为3个种。本文在黑龙江、吉林、辽宁、河北、山西、山东、江苏、内蒙古对本复合体进行了居群取样，共46个居群。其内进行了引种、栽培实验。生物学特性观察、杂交、染色体观察，同工酶比较，以及用生物统计学进行了性状分析、数量分类学分析、茎解剖和芯粉的观察。 此复合体主要进行异花授粉（因为雄蕊先熟)、没发现无融合生殖。实生苗当年只长基生叶，第二年才抽茎开花。 2、此复合体酯酶酶谱的变异范围相当宽，有时。同一居群内的变异反而比居群间的还要大。因此酶谱在本复合体内的分类价值不大。 3、通过对32个居群进行染色体记数，友现辽东、辽西(绝大部分地区)、山西霍县的居群为二倍体（2n=34），另外还在锦州发现有几个个体2n = 36。其它地方的居群都力四倍体，2n=68、居群间的染色体形态相当一致。 4、通过对移栽自黑龙江口(A•gmelinii的二个居群)、北京(A•polyantha)，山西东部(A•gmelinii和A•polyantha)，锦州的二倍体共9个居群进了杂交试验，发现四倍体间能得到一些F1种子、而辽西二倍体与其它类群间却得不到F1种子。 5、性状分析，茎解剖和数量分类研究发现花的大小和形状、果实的大小和齿的有无、叶的大小和形状（长/宽），往头与花冠相对长度和种子形状等都有一定的分化，尤其是髓锥管束的有无等。通过分析可以分辨出3个二倍体和5个四倍体宗。在 3个二倍体宗中，辽西西部宗(A•polyantha var•ootra ta)与其它两个在形态上已经分化得相当分明，无疑可以作种处理，A•contracta(Kitag) Qu et Hang，另二个（分别在辽东和山西霍县）在形态上也已分化得相当明显，达到了种水平，A•polyantha和A•gme1ireii在5个四倍体宗中，山西东北部和河北的西北部高海拔分布的一个宗，由于它的花萼裂片具齿且狭长，花冠狭长而大、果实大，茎常中空等特征，仍然保留种的地位（A•elata)。另外分布于山西高海拔(包括四倍和二倍体）以及内蒙、吉林、黑龙江…三个宗，虽然有分化，但不明显，尤其是它们都无髓锥管束或仅少数个体有的特征，本文把它们处理为同一种(A•gmelinii)的3个不同三种。最后一个是分布于辽宁最西部、河北、山东、江苏北部、安徽、河南、陕西和甘肃的四倍体宗、它在形态上与辽东的二倍体相似、故作为A•polyantha的两个亚种处理，前者为A•polyantna sspscabricalyx后者为A•P•ssp polyantha： 可以推测过去此复合体的分布范围相当宽，后来逐渐分化成三个二倍宗体，由辽东的A•polyantha ssplyantha(2x)衍生的四倍体，逐渐向西迁移，山西霍县的二倍体产生的四倍体逐渐向北迁移直至东西伯利亚东南部和远东，最后分化成三个亚种。 本文采用杂交指数法，对山西东部和河北西部的A•gme1inii和A•polyantha居群间的杂交性近行了研究，认为两个种在四倍体水平的杂交可能是这两个种间性状在该地区彼此过渡的主要原因。

中国紫草科花粉形态的研究

本文借助扫描电镜和光学显微镜系统地观察和研究了中国紫草科42属129种植物的花粉形态，并对其中39属45种植物花粉壁做了起薄切片，并用透射电镜研究其外壁内部的超微结构。 并根据花粉形态特征，做了聚类分析。 紫草科花粉是一个多类型的类群。大多数属种为等极花粉，少数为异极，稀为亚等极。形状以茧形花粉占优势，其次是长球形或近长球形，还有少数为球形或近球形、椭球形、卵球形，个别种为哑铃形。花粉大小变异也很大，从最小的6.09×3.4num到最大的69.16um。萌发孔结构复杂，类型繁多，在本文观察的129种植物中就有二十三种萌发孔类型，它们不仅在萌发孔数量上面且在其形状和结构上也有差别，其中以三孔沟、 三孔沟和三假沟为本科的主要类型。外壁主要为光滑和具或多或少的孔穴，少数种还具有刺状、网状、瘤状或短棒等纹饰。外壁在透射电镜下分层性明显，为完全覆盖层，偶具穿孔，柱状层大多数分化较好，小柱直立， 少数柱状层分化不明显，成团块状或结构模糊，柱状层厚度不等，有的稍厚，但有的很薄，基层一般都存在，个别种不明显，但有的的种又特别厚，外壁内层一般在萌发孔区加厚，少数加厚不明显或稍加厚。内壁明显或否。根据花粉形态特征，编了属的检索表。 根据花粉形态的演化规律，本文讨论了紫草科花粉的萌发孔、形状、大小、外壁纹饰及壁的结构等的演化趋势。 在研究花粉形态特征的基础上， 对紫草科的系统分类进行了探讨;对其中归属争议比较大的某些类群， 从花粉形态上提出了自己的观点。 最后讨论了花粉的形态与其适应性的关系。 从其花粉形态特征和高度的适应性上，显示出紫草科是一个适应昆虫传粉， 并且比较进化的类群。

黔东南小香羊与贵州原有其它山羊品种的线粒体DNA 多态性比较

用B am H É、B g lÉ、B g lÊ、D raÉ、E coR É、E coR Í、H indË、Kp nÉ、 P stÉ、P vuÊ、S acÉ、S a lÉ、Sm aÉ、S tuÉ、X hoÉ 15 种识别6 碱基的限制性内 切酶对黔东南小香羊和贵州原有3 个地方山羊品种的93 只个体的m tDNA 进行分 析表明, B am H É、H indË 和S a lÉ 3 种酶表现多态性; 共检出18 种限制性多态型, 归纳得到3 种单倍型, 以单倍型É 和Ê 为基本单倍型。根据此2 种基本单倍型在所 比较各品种中的不同分布比例, 以及遗传距离分析和品种间的聚类关系, 表明黔东 南小香羊的群体遗传构成与贵州省原有其它3 个山羊品种不同, 从而为进一步确认 其为一独立的品种提供了必要的分子生物学依据。

云南龙陵黄山羊的核型及C－带和Ag－NOR_s研究

采用外周血淋巴细胞培养及染色体分带技术，分析了龙陵黄山羊的核型，Ｃ—带和银染核仁组织区（Ａｇ—ＮＯＲ＿ｓ），结果表明：龙陵黄山羊染色体数为２ｎ＝６０，常染色体及Ｘ染色体为端部着丝粒染色体，Ｙ染色体最小，为中部着丝粒染色体。常染色体着丝粒区均显示Ｃ—带，性染色体未显Ｃ—带．雌性银染核仁组织区（Ａｇ—ＮＯＲ＿ｓ）分布于Ｎｏ．１，２，３，４，５，２５号染色体，雄性分布于Ｎｏ．１，２，２５号染色体，显示了性别及分布多态性。研究还发现三种不同的联合（ＡＳＳＯＣＩＡＴＩＯＮ）。

Mechanism study on the frequent variations of cell-bound microcystins in cyanobacterial blooms in Lake Taihu: Implications for water quality monitoring and assessments

Although Microcystis-based toxins have been intensively studied, previous studies using laboratory cultures of Microcystis strains are difficult to explain the phenomenon that microcystin concentrations and toxin variants in natural blooms differ widely and frequently within a short-term period. The present study was designed to unravel the mechanisms for the frequent variations of intracellular toxins related to the differences in cyanobacterial colonies during bloom seasons in Lake Taihu, China. Monitoring of Microcystis colonies during warm seasons indicated that the variations in microcystins in both concentrations and toxin species were associated with the frequent alteration of Microcystis colonies in Lake Taihu. High concentration of microcystins in the blooms was always associated with two Microcystis colonies, Microcystis flos-aquae and Microcystis aeruginosa, whereas when Microcystis wesenbergii was the dominant colonial type, the toxin production of the blooms was low. Additionally, environmental factors such as temperature and nutrition were also shown to have an effect on the toxin production of the blooms, and may also potentially influence the Microcystis species present. The results of the present study provides insight into a new consideration for quick water quality monitoring, assessment and risk alert in cyanobacterium- and toxin-contaminated freshwaters, which will be beneficial not only for water agencies but also for public health. (C) 2009 Elsevier Ltd. All rights reserved.

Age structure, growth and mortality estimates of an endemic Ptychobarbus dipogon (Regan, 1905) (Cyprinidae: Schizothoracinae) in the Lhasa River, Tibet

Ptychobarbus dipogon is an endemic fish in the Yarlung Tsangpo River, but its biology is poorly known. We sampled 582 specimens (total length, TL, between 70.6 and 593.0 mm) from April 2004 to August 2006 in the Lhasa River, Tibet. We estimated ages based on the counts of alternating opaque and translucent zones (annuli) in thin transverse sections of lapilli otoliths. Ages ranged from 1(+) to 23(+) years for males and 1(+) to 44(+) for females. The observed 44(+) years was the oldest reported for schizothoracine fishes. Females attained a larger size than males. The TL weight relationship was W=7.12 x 10(-6)TL(3.006) for combined sexes. The growth parameters fitted von Bertalanffy growth functions were L-infinity = 598.66 mm, k=0.0898 year(-1), t(0)=-0.7261 year and W-infinity = 1585.38 g for females and L-infinity = 494.23mm, k=0.1197 year(-1), t(0)=-0.7296 year and W-infinity = 904.88g for males. The longevities of 32.7 year for females and 24.3 year for males were similar to the observed ages. Using an empirical model we estimated the instantaneous rate of total mortality (Z) at 0.28 per year in the lower reaches. Z in the upper and middle stocks was close to the M because of unexploited or lightly exploited stock. Protracted longevity, slow growth, low natural mortality and large body size were typical characteristics of P. dipogon. The current declining trend of P. dipogon could be prevented by altering fishing regulations.

Antibunching and blinking from a single colloidal CdSe quantum dot

We have investigated the optical properties of single CdSe/ZnS nanocrystals by conducting combinations of experiments on antibunching and photoluminescence intermittence under different experimental conditions. Based on photoluminescence in an antibunching experiment, we analyzed the emission lifetime of QDs by using stretched exponentials. The difference between the parameters obtained from average lifetimes and stretched exponents were analyzed by considering the effect of nonradiative emission. An Auger-assisted tunneling model was used to explain the power law exponents of off time distribution. The power law exponent under high excitation power was correlated with a higher Auger ionization rate. Using the parameters obtained from stretched exponential function and power law, the antibunching phenomena at different time and under different excitation intensity were analyzed.