异戊二烯稀土催化聚合过程中配合物结构及其转化的~(13)C-NMR研究

本文用~(13)C-NMR研究了异戊二烯(IP)在均相催化剂(CF_3CO_2)_2LnCl·EtOH—(i-Bu)AlH—o-C_6D_4Cl_2作用下的聚合过程。单体首先被活化同稀土配位生成η~4-IP稀土配合物(反式和顺式),然后η~4-IP的C-3和C-4插入Ln-H键生成η~3-烯丙基稀土配合物——η~3-(2-甲基)丁烯基稀土配合物(同式和对式)。二维~(13)C-NMR交换谱表明η~4-IP和0η~3-烯丙基的每对异构体在常温下分别进行慢交换反应(互变异构),这一过程使插入反应在常温下得以进行。

Ontogenetic development of digestive enzymes and effect of starvation in miiuy croaker Miichthys miiuy larvae

The ontogenetic development of the digestive enzymes amylase, lipase, trypsin, and alkaline phosphatase and the effect of starvation in miiuy croaker Miichthys miiuy larvae were studied. The activities of these enzymes were detected prior to exogenous feeding, but their developmental patterns differed remarkably. Trypsin activity continuously increased from 2 days after hatching (dah), peaked on 20 dah, and decreased to 25 dah at weaning. Alkaline phosphatase activity oscillated at low levels within a small range after the first feeding on 3 dah. In contrast, amylase and lipase activities followed the general developmental pattern that has been characterized in fish larvae, with a succession of increases or decreases. Amylase, lipase, and trypsin activities generally started to increase or decrease at transitions from endogenous to exogenous feeding or diet changes, suggesting that these enzymatic activities can be modulated by feeding modes. The activities of all the enzymes remained stable from 25 dah onwards, coinciding with the formation of gastric glands and pyloric caecum. These results imply that specific activities of these enzymes underwent changes due to morphological and physiological modifications or diet shift during larval development but that they became stable after the development of the digestive organs and associated glands was fully completed and the organs/glands functioned. Trypsin and alkaline phosphatase were more sensitive to starvation than amylase and lipase because delayed feeding up to 2 days after mouth opening was able to adversely affect their activities. Enzyme activities did not significantly differ among feeding groups during endogenous feeding; however, all activities were remarkably reduced when delayed feeding was within 3 days after mouth opening. Initiation of larvae feeding should occur within 2 days after mouth opening so that good growth and survival can be obtained in the culture.

Molecular phylogeny and species identification of pufferfish of the genus Takifugu (Tetraodontiformes, Tetraodontidae)

The phylogenetic relationships and species identification of pufferfishes of the genus Takifugu were examined by use of randomly amplified polymorphic DNA (RAPD) and sequencing of the amplified partial mitochondrial 16S ribosomal RNA genes. Amplifications with 200 ten-base primers under predetermined optimal reaction conditions yielded 1962 reproducible amplified fragments ranging from 200 to 3000 bp. Genetic distances between 5 species of Takifugu and Lagocephalus spadiceus as the outgroup were calculated from the presence or absence of the amplified fragments. Approximately 572 bp of the 16S ribosonial RNA gene was amplified, using universal primers, and used to determine the genetic distance values. Topological phylogenic trees for the 5 species of Takifugu and outgroup were generated from neighbor-joining analysis based on the data set of RAPD analysis and sequences of mitochondrial 16S rDNA. The genetic distance between Takifugu rubripes and Takifugu pseudommus was almost the same as that between individuals within cacti species, but much smaller than that between T. rubripes, T. pseudommus, and the other species. The molecular data gathered from both analysis of mitochondria and nuclear DNA strongly indicated that T. rubripes and T. pseudommus should be regarded as the same species. A fragment of approximately 900 bp was amplified from the genome of all 26 T. pseudommus individuals examined and 4 individuals of intermediate varieties between T. rubripes and T. pseudommus. Of the 32 T. rubripes individuals, only 3 had the amplified fragment. These results suggest that this fragment may be useful in distinguishing between T. rubripes and T. pseudommus.

Progress of large-scale air-sea interaction studies in China

This paper summarizes the progress of large-scale air-sea interaction studies that has been achieved in China in the four-year period from July 1998 to July 2002, including seven aspects in the area of the air-sea interaction, namely air-sea interaction related to the tropical Pacific Ocean, monsoon-related air-sea interaction, air-sea interaction in the north Pacific Ocean, air-sea interaction in the Indian Ocean, air-sea interactions in the global oceans, field experiments, and oceanic cruise surveys. However more attention has been paid to the first and the second aspects because a large number of papers in the reference literature for preparing and organizing this paper are concentrated in the tropical Pacific Ocean, such as the ENSO process with its climatic effects and dynamics, and the monsoon-related air-sea interaction. The literature also involves various phenomena with their different time and spatial scales such as intraseasonal, annual, interannual, and interdecadal variabilities in the atmosphere/ocean interaction system, reflecting the contemporary themes in the four-year period at the beginning of an era from the post-TOGA to CLIVAR studies. Apparently, it is a difficult task to summarize the great progress in this area, as it is extracted from a large quantity of literature, although the authors tried very hard.

地下咸水的化学特征及其在水产养殖中的应用

地下咸水的化学成分与现代海水基本相同，它本身不带病毒，与海水也没有连接的渠道，故海水中的病毒宿主难以侵入，因此，它可以做为海水养殖的一种替代水体，在水产养殖方面有非常广阔的应用前景。本论文首次对用于养殖的胶州地区的地下咸水的形成原因和化学组分特征作了系统阐述。主要的研究内容和研究结果包括：1．咸水入侵和稀释作用是形成该地区地下咸水的主要原因。现代海水和卤水入侵及临近河口区淡水对地下卤水的稀释作用是形成该地区地下咸水的两种主要原因。地质调查结果表明，胶州地区属于地下卤水远景分布区，该地区有不边疆分布的斑块状的地下卤水存在，对地下水的超采造成地下水水位的下降，从而引起咸水入侵。在大沽河河口地区，河流淡水对地下卤水的稀释也是是该区地下咸水形成的一个原因。2．地下咸水的主要化学组分特征 在地下咸水的常量元素分布中，由于地下水流沉积物表面时产生的溶滤作用、离子交换吸附及还原环境下脱硫酸菌的作用使Ca~(2+)/Cl~-、Mg~(2+)/Cl~－、Na~+/Cl~-值与海水中的相应组分的比值相比，有不同程度的升高，SO_4~(2-)/Cl~-明显降低，K~+/Cl~-的值在不同的地区差异较大。通过对几个地区地下水中铁、锰的含量对比，发现其值远高于海水中的含量，可高达每升几毫克，这主要是由于在地下水的还原环境和较低的pH条件下，铁、锰的氧化物较易还原溶出，并讨论了不同地区的Mn/Fe值由于受Fe~(2+)、Mn~(2+)这两种还原产物稳定性的没和铁锰氧化物易被还原的程度不同这两个因素的影响，分别呈现出大于1和小于1的情形。对地下水中微量元素铜、铅、锌、镉的分析表明，这些元素在地下水中的含量与海水中的含量在同一个数量级，差异不显著。以Cl~-为参比因子，从所求得的相关关系来看，锌和铜在地下水中呈较好的保宋性分布，即没有显著的添加或去除行为，铅和镉的保守性较差。地下水中的营养盐分布与海水也有着显著不同，在地下咸水的Eh和pH分布范围内，NH_4~+态氮是地下水中无机氮分布的主要形式，并且由于吸附在粘土中的硅酸盐矿物的转出，地下咸水中的SiO_3~(2-)含量显著偏高。3．Ca~(2+)、Mg~(2+)对对虾生长的影响 利用正交实验证实了Ca~(2+)/Mg~(2+)比值、Ca~(2+)+Mg~(2+)总量以及二者之间的交互作用对对是生长都有显著性影响。对虾生长适宜的Ca~(2+)/Mg~(2+)比值范围是1:1～1:3，对是能在Ca~(2+)/Mg~(2+)比值为1：10的水环境中正常生长，只要有一定的Ca~(2+)+Mg~(2+)总量。较低的Ca~(2+)浓度可能会成为导致对虾存活率降低的原因。

扎曲鹅观草——青海禾本科一新种

对青海禾本科一新种——扎曲鹅观草（Roegneria zaquensis Y.H.Wu et S.L.Lu）进行了形态描述和图解。该种与玉树鹅观草（R.yushuensisL.B.Cai）相近,但本种的叶鞘顶端两侧具叶耳,穗状花序灰绿色,长10～15 cm,基部被顶生叶鞘所包;颖稍短,第一颖长2～3 mm,第二颖长4～5 mm;外稃背部无毛,芒长15～30 mm,第一外稃长10～12 mm;花药黄色或带绿色,长2～2.5 mm,可以区别。

藏羚寄生蠕虫卵粪检调查初报

2004年12月25日-2005年1月5日对位于青藏公路楚玛尔河大桥附近集群的藏羚（Pantholops hodgsoni），随机拣取其新鲜粪便共计36份带回实验室。利用漂浮法、沉淀法对粪样进行寄生虫蠕虫卵检查，结果显示，粪样中存在有细颈属（Nematodirus）、马歇尔属（Marshallagia）线虫卵和莫尼茨属（Moniezia）绦虫卵，其感染率在19．4％-94．4％之间，感染强度（EPG）分别为5．58、5．11和2．86。结果表明，冬季藏羚的寄生蠕虫感染率高，但感染种类少和感染强度低。

Simultaneous determination of monoamine and amino acid neurotransmitters in rat endbrain tissues by pre-column derivatization with high-performance liquid chromatographic fluorescence detection and mass spectrometric identification

A sensitive and efficient method for simultaneous determination of glutamic acid (Glu), gamma-amino-butyric acid (GABA), dopamine (DA), 5-hydroxytryptamine (5-HT) and 5-hydroxyindole acetic acid (5-HIAA) in rat endbrains was developed by high-performance liquid chromatography (HPLC) with fluorescence detection and on-line mass spectrometric identification following derivatization with 1,2-benzo-3,4-dihydrocarbazole-9-ethyl chloroformate (BCEOC). Different parameters which influenced derivatization and separation were optimized. The complete separation of five neurotransmitter (NT) derivatives was performed on a reversed-phase Hypersil BDS-C-18 column with a gradient elution. The rapid structure identification of five neurotransmitter derivatives was carried out by on-line mass spectrometry with electrospray ionization (ESI) source in positive ion mode, and the BCEOC-labeled derivatives were characterized by easy-to-interpret mass spectra. Stability of derivatives, repeatability, precision and accuracy were evaluated and the results were excellent for efficient HPLC analysis. The quantitative linear range of five neurotransmitters were 2.441-2 x 10(4) nM, and limits of detection were in the range of 0.398-1.258 nM (S/N = 3:1). The changes of their concentrations in endbrains of three rat groups were also studied using this HPLC fluorescence detection method. The results indicated that exhausting exercise could obviously influence the concentrations of neurotransmitters in rat endbrains. The established method exhibited excellent validity, high sensitivity and convenience, and provided a new technique for simultaneous analysis of monoamine and amino acid neurotransmitters in rat brain. (C) 2008 Elsevier B.V. All rights reserved.

无模型自由曲面结构光测量路径规划研究

根据应用对象的不同,结构光测量路径规划分为基于CAD模型的测量路径规划和无模型的测量路径规划。本文针对无模型的测量路径规划问题,提出了一种基于机器人特征点示教和准均匀B样条插值的半自动自由曲面测量路径规划策略。该策略充分考虑了自由曲面的特征及结构光测量路径的特殊要求,通过少量特征点的示教和准均匀B样条插值,半自动的规划出测量路径。实验证明,该规划策略能提高无模型工件测量的效率,且该策略已在智能测量建模加工一体化装备中得到了应用。

非接触式机器人直线轨迹测量系统

本文给出了一种基于视觉的、造价低廉实用的非接触式机器人直线轨迹测量系统 .该测量系统由结构光视觉传感器、测量轨道、主控计算机及相关软件组成 .视觉传感器可固定于机器人末端 .当机器人末端带动视觉传感器沿测量轨道做直线运动时 ,通过传感器测量相对测量轨道的连续位姿关系 ,就可间接描述机器人末端的运动轨迹 .当重复同一直线运动时 ,可检测出机器人的轨迹重复性 .本文综述了机器人直线轨迹测量设备的研究现状 ,介绍了轨迹检测系统的测量原理 ,重点讨论了该测量系统的两个关键技术 :空间特征点的图象提取技术和三维坐标计算方法 ,并描述了该系统的结构、性能指标和测量试验结果 .

防汛与兴利调度指挥信息系统

本文简要说明了防汛与兴利调度指挥信息系统的意义、目的和任务;介绍了系统的基本组成、逻辑结构、信息流模型和数据通信网络结构;并论述了系统中有关综合通信网络、洪水预报及水库调度模型,信息集成和系统应用集成三个主要方面的关键技术问题及解决途径．

贵州土地石漠化类型时空演变过程及其评价

构建了贵州20世纪80年代、90年代和21世纪初等3期历史石漠化数据，利用其空间变换和数学模型详细探讨和评价了石漠化的时空演变过程，研究发现：（1）研究时段内贵州省石漠化总面积变化不明显，但石漠化内部类型之间的相互演变非常显著，各类型之间的演变具有转移、多变、“此消彼长”的特点。（2）石漠化的时空演变过程可分为单变方式、层变方式、返变方式等3种基本类型，其中以层变方式为主，单变方式为辅，返变方式较少。（3）石漠化正向演变与逆向演变并存，治理速度赶不上恶化速度，两者的比值为82.29%，局部治理，整体恶化。（4）各石漠化类型总的演变速率是398.31km^2·a^-1，石漠化等级越高，演变速率越慢。（5）石漠化演变频率最快的是中度石漠化和潜在石漠化，轻度石漠化的演变频率明显低于中度石漠化。对石漠化的空间演变区域特征和影响因子做了宏观的定性分析、并根据石漠化演变特点对综合治理提出了相应的建议。

羌塘盆地侏罗纪双壳类化石组合及古环境

海相侏罗系是羌塘盆地发育最全、分布最广泛的沉积层系。作者根据详细的野外地质工作，收集了典型剖面的岩相、沉积构造和大量的化石，并借鉴、总结前人的研究成果，对该区双壳类生物地层进行较系统的、全面的分析研究，划分了五个双壳类化石组合：Camptonectes auritus—Pteroperna costatula，Eomiodon angulatus-lsognomon（Mytiloperna）bathonica，Camptonectes laminatus-Anisocardia beaumonti，Anisocardia tenera—Modiala biparta以及Gervillella aviculoides—Radulopecten fibrosus；认为该区雁石坪群的时代从巴柔期至牛津-基末里期，从而建立起生物地层格架及年代地层格架。根据沉积标志以及典型的化石组合，探讨了研究区古地理环境，并识别出滨海、潮坪、溻湖、碳酸盐台地以及碳酸盐缓坡等古沉积环境，揭示了各时期自然地理状况，对探索东特提斯地区的构造演化和双壳类的生态演变都有重要的意义。