水体悬移质对重金属吸附规律研究——以长江宜昌段为例

随着长江三峡工程的建设 ,上游来水的流速在此减缓 ,随江水而下的大量泥沙在此沉淀 ,将使坝下 (长江中下游 )水中的悬移质浓度降低、粒径改变 ,从而改变水环境容量。利用长江宜昌江段的周年悬移质样及水样 ,研究了悬移质对重金属 (铜、锌、铅、镉及铬 )的吸附特征。结果表明 ,悬移质对上述金属的吸附可用Freundlich型及Langmuir型等温式较好进行拟合 ;当较高浓度的金属污染物排入江水后 ,在吸附及沉淀的共同作用下 ,浓度明显降低 ;单位悬移质的吸附量随悬移质浓度降低而上升 ,但总吸附量降低 ,从而

Composite electrospun gelatin fiber-alginate gel scaffolds for mechanically robust tissue engineered cornea

A severe shortage of good quality donor cornea is now an international crisis in public health. Alternatives for donor tissue need to be urgently developed to meet the increasing demand for corneal transplantation. Hydrogels have been widely used as scaffolds for corneal tissue regeneration due to their large water content, similar to that of native tissue. However, these hydrogel scaffolds lack the fibrous structure that functions as a load-bearing component in the native tissue, resulting in poor mechanical performance. This work shows that mechanical properties of compliant hydrogels can be substantially enhanced with electrospun nanofiber reinforcement. Electrospun gelatin nanofibers were infiltrated with alginate hydrogels, yielding transparent fiber-reinforced hydrogels. Without prior crosslinking, electrospun gelatin nanofibers improved the tensile elastic modulus of the hydrogels from 78±19. kPa to 450±100. kPa. Stiffer hydrogels, with elastic modulus of 820±210. kPa, were obtained by crosslinking the gelatin fibers with carbodiimide hydrochloride in ethanol before the infiltration process, but at the expense of transparency. The developed fiber-reinforced hydrogels show great promise as mechanically robust scaffolds for corneal tissue engineering applications. © 2013 Elsevier Ltd.

Reynolds number effects on scalar dissipation rate transport and its modeling in turbulent premixed combustion

The effects of turbulent Reynolds number, Ret, on the transport of scalar dissipation rate of reaction progress variable in the context of Reynolds averaged Navier-Stokes simulations have been analyzed using three-dimensional simplified chemistry-based direct numerical simulation (DNS) data of freely propagating turbulent premixed flames with different values of Ret. Scaling arguments have been used to explain the effects of Ret on the turbulent transport, scalar-turbulence interaction, and the combined reaction and molecular dissipation terms. Suitable modifications to the models for these terms have been proposed to account for Ret effects, and the model parameters include explicit Ret dependence. These expressions approach expected asymptotic limits for large values of Ret. However, turbulent Reynolds number Ret does not seem to have any major effects on the modeling of the term arising from density variation. Copyright © Taylor and Francis Group, LLC.

青藏高原的隆升与鰋鮡鱼类(鲇形目:鮡科)的隔离分化

系统发育和生物地理学分析认为喜马拉雅地区　　鱼类的物种分化过程与青 藏高原的隆升有直接的关系，并可用隔离分化假说加以解释．　鱼类的祖先与目前 广布的纹胸　属鱼类和／或　属鱼类相似．在Ｔｅｔｈｙｓ海封闭、印度板块与欧亚大陆碰撞 的初期，纹胸　属鱼类或经属鱼类广泛分布于青藏高原地区．更新世后，随着碰撞的 加深，青藏高原逐步隆起并造就了山区水系的急流环境，　　鱼类就是在这种环境因 子的压迫下从类纹胸　属鱼类产生的．目前跨喜马拉雅山分布的原　属就是　　鱼类 中最原始的种类．在青藏高原的３次隆升过程中，随着该区域水

人工四倍体鲤鲫的产生

在人工诱导的复合三倍体鲤鱼成熟个体中有极个别个体产出的卵既保留了原有的3套染色体,又能与一套外来精核融合产生四倍体。1997年人工产生的8000多尾鲤鲫四倍体鱼经细胞遗传学研究分析鉴定,结果所有的个体都有4套染色体组,染色体数目在185～210之间,众数为200,四倍体比率为100％。这表明人工复合三倍体鲤鱼的生殖方式十分独特,绝大部分个体的成熟卵可借助于外来精子的激动进行自然雌核发育;而有极个别个体的成熟卵能与外来精子融合产生四倍体个体。四倍体鲤鲫的形态特征像鲫鱼。

The effects of non-unity lewis numbers on turbulent premixed flame interactions in a twin V-flame configuration

The influence of Lewis number on turbulent premixed flame interactions is investigated using automatic feature extraction (AFE) applied to high-resolution flame simulation data. Premixed turbulent twin V-flames under identical turbulence conditions are simulated at global Lewis numbers of 0.4, 0.8, 1.0, and 1.2. Information on the position, frequency, and magnitude of the interactions is compared, and the sensitivity of the results to sample interval is discussed. It is found that both the frequency and magnitude of normal type interactions increases with decreasing Lewis number. Counternormal type interactions become more likely as the Lewis number increases. The variation in both the frequency and the magnitude of the interactions is found to be caused by large-scale changes in flame wrinkling resulting from differences in the thermo-diffusive stability of the flames. During flame interactions, thermo-diffusive effects are found to be insignificant due to the separation of time scales. © 2013 Copyright Taylor and Francis Group, LLC.

微囊藻毒素对鱼蛋白磷酸酶抑制作用的研究

国家自然科学基金39400024;淡水生态与生物技术国家重点实验室资助

鮊亚科类系统发育初探（鲤形目：鲤科）

Ｎ亚科鱼类系统发育初探（鲤形目：鲤科）乐佩琦，罗云林（中国科学院水生生物研究所，武汉４３００７２）关键词鲤形目，鮊亚科，系统发育ＰＲＥＬＩＭＩＮＡＲＹＳＴＵＤＩＥＳＯＮＰＨＹＬＯＧＥＮＹＯＦＳＵＢＦＡＭＩＬＹＣＵＬＴＲＩＮＡＥ（ＣＹＰＲＩＮＩＦＯＲＭ...

分子生态毒理学研究进展及其在水环境保护中的意义

分子生态毒理学研究进展及其在水环境保护中的意义徐立红，张甬元，陈宜瑜（中国科学院水生生物研究所，武汉４３００７２）关键词水环境，分子生态毒理学，水生动物，指标，早期报警ＴＨＥＡＤＶＡＮＣＥＳＯＦＭＯＬＥＣＵＬＡＲＥＣＯＴＯＸＩＣＯＬＯＧＹＡＮＤＩＴＳ...

世界豚类饲养设施的设计标准与白暨豚馆的设计

<正> 豚池是豚类动物饲养的基本条件,建设符合豚类动物生活,生长和繁殖所必需的饲养设施,是豚类饲养成败的关键之一。作者通过12年来白鱀豚Lipotes vexillifer饲养实践的总结,并实地考察了美、英、日、德国、法国、荷兰、瑞士和香港等国家和地区的豚类饲养设施,结合我国国情,设计了白暨豚饲养繁殖系统——新白鱀豚馆,为我国豚类养殖事业的发展打下了基础。

鱼类同工酶和蛋白质的聚丙烯酰胺梯度凝胶电泳法

<正> 同工酶分析一般常用淀粉凝胶电泳进行,但它常受淀粉质量的制约,在淀粉的水解和制胶过程较难标准化,因而不易掌握,其机械强度不够也不易操作。而聚丙烯酰胺凝胶电泳具有优于淀粉凝胶电泳的一些特性,如有较高的分辨率、机械强

Statistics of reaction progress variable and mixture fraction gradients from DNS of turbulent partially premixed flames

Statistically planar turbulent partially premixed flames for different initial intensities of decaying turbulence have been simulated for global equivalence ratios = 0.7 and 1.0 using three-dimensional, simplified chemistry-based direct numerical simulations (DNS). The simulation parameters are chosen such that the flames represent the thin reaction zones regime combustion. A random bimodal distribution of equivalence ratio is introduced in the unburned gas ahead of the flame to account for the mixture inhomogeneity. The results suggest that the probability density functions (PDFs) of the mixture fraction gradient magnitude |Δξ| (i.e., P(|Δξ|)) can be reasonably approximated using a log-normal distribution. However, this presumed PDF distribution captures only the qualitative nature of the PDF of the reaction progress variable gradient magnitude |Δc| (i.e., P(|Δc|)). It has been found that a bivariate log-normal distribution does not sufficiently capture the quantitative behavior of the joint PDF of |Δξ| and |Δc| (i.e., P(|Δξ|, |Δc|)), and the agreement with the DNS data has been found to be poor in certain regions of the flame brush, particularly toward the burned gas side of the flame brush. Moreover, the variables |Δξ| and |Δc| show appreciable correlation toward the burned gas side of the flame brush. These findings are corroborated further using a DNS data of a lifted jet flame to study the flame geometry dependence of these statistics. © 2013 Copyright Taylor and Francis Group, LLC.

第二固氮系统在蓝细菌红萍鱼腥藻中的发现

<正> 人们一般认为金属钼是生物固氮必需的条件,钼是固氮酶的主要催化活性的组成部分。早先一些学者曾研究以钒、锰代替钼的氮固定作用,到1980年美国的Bishop等人首先提出棕色固氮菌(Azotobacter vinelandii)具有不含铝的第二固氮系统。通过棕色固氮菌缺失编码固氮酶蛋白基因突变株研究发现,该菌株并不失去