Theoretical Study of Dinitrogen Activation by Iron, Ruthenium, and Osmium

铁、钌、锇对氮活化的理论研究 摘要 氮的活化与固定一直是实验和理论研究的重要课题之一，无论是工业固氮还是生物固氮或者是无机固氮，其活性中心都是以过渡金属为主要成份，因而研究过渡金属原子、团簇和表面与N2之间的相互作用，对于认识已有的催化合成氨的反应机理、探索生物固氮的机制和无机固氮的条件具有十分重要的意义。本文选用密度泛函理论（DFT），系统而详细地研究了铁族单原子、双原子簇对N2络合活化作用。论文主要包括三部分的内容： 第一部分第一章我们概述了近年来在实验和理论方面研究工业合成氨、生物固氮、液相固氮、无机固氮和气相过渡金属原子和簇与氮的反应的进展和存在的问题，提出本文将研究的内容。第二...Theoretical Study of Dinitrogen Activation by Iron, Ruthenium, and Osmium Abstract Molecular nitrogen (N2) surrounds us as the major component of the atmosphere here on Earth. Only a few organisms are capable of utilizing this plentiful source of nitrogen. The process by which N2 is incorporated into biological systems is referred to as nitrogen fixation and involves the nitrogenase enzym...学位：理学博士院系专业：化学化工学院化学系_物理化学(含化学物理)学号：B19992502

用离散-连续模型计算NH_2~-,NH_3和NH_4~+的溶剂化自由能

通过理论计算推测 NH- 2 ,NH3 和 NH+4在水溶液第一溶剂化层中与之直接作用的水分子分别为 2 ,4和 4个 ,并采用离散 -连续模型计算了 NH- 2 ,N H3 和 NH+ 4在水溶液中的溶剂化自由能 .结果表明 ,由于离散 -连续模型在从头算水平考虑了溶质分子与第一溶剂化层溶剂分子之间的作用 ,能更准确地描述溶剂化作用 .此外 ,采用更加符合溶液中真实情况的溶剂化构型 ,能得到更准确的溶剂化性质

聚碳硅烷熔体的稳态流变性能

采用自制装置对聚碳硅烷(PCS)熔体进行预处理。通过预处理获得三种不同分子量的PCS,并对其进行物理化学和稳态流变性能测试。结果表明,预处理后的PCS其数均分子量为1000 g/mol~1400 g/mol,属低聚物。在温度范围240℃~260℃和剪切速率范围0.001 s-1~10 s-1内有明显的剪切变稀现象。在测试的温度范围内,剪切变稀区的非牛顿指数随温度升高先减小后增大。预处理后的PCS粘流活化能为120 kJ/mol~180 kJ/mol,比一般高聚物的高得多

第十八届美国理论与应用力学大会总结

1会议概况2018年6月5—9日,第18届美国理论与应用力学大会(18th U.S. National Congress of Theoretical and Applied Mechanics, USNCTAM2018)在美国芝加哥召开.本次大会由美国力学国家委员会和中国力学学会联合主办,旨在探讨和交流近四年世界范围内在理论和应用力学领域的基础研究、创新技术的最新进展,吸引了来自世界各地的近千名专家学

Application of Aptamers in Biomedicine

Corresponding author e-mail:[email protected]; [email protected][中文文摘]核酸适体是经配体指数富集系统进化技术(SELEX)筛选获得的一类能够特异性地结合离子、分子,甚至整个细胞的单链DNA或者RNA分子。本文介绍了核酸适体及相关筛选技术SELEX;综述了近年来以提高筛选效率和效果为目标的核酸适体筛选技术新进展;列举了核酸适体在无机离子、小分子、生物大分子和肿瘤细胞检测、肿瘤标记物的发现等方面的应用;讨论了基于核酸适体的靶向治疗策略;最后对核酸适体在生物医学上的应用前景进行了展望。[英文文摘]Aptamers are a new class of nucleic acid probes,which are ssDNA /RNA molecules selected to target a wide range of ions,molecules and even cells through SELEX(systematic evolution of ligands by exponential enrichment) technique.This paper presents aptamers and traditional selection approaches;summarizes recent efforts in developing new aptamer selection strategies;reviews new approaches for biomedical analysis,disease biomarker discovery and target therapy.Finally,the potential of aptamers in biomedicine is also discussed.国家重点基础研究发展计划(973)项目(No.2010CB732400); 福建省自然科学基金项目(No.2008J0107)资

Studies on mitochondrial DNA control region and cytochrome b gene sequences of whitespotted bambooshark,Chiloscyllium plagiosum

对厦门和湛江海域的条纹斑竹鲨[Chiloscyllium plagiosum(Bennett,1830)]的线粒体DNA控制区和细胞色素b(Cytb)基因进行PCR扩增和测序,获得线粒体DNA控制区、Cytb基因和tRNAPro基因全序列(GenBank序列号:EU363740~EU363752)。结果表明,tRNAPro基因长度为69bp,控制区长度为1094~1096bp,Cytb基因全序列长度为1146bp。tRNAPro基因非常保守,未发现碱基变异。所测30个个体中,控制区只有4个多态位点,5种不同的单倍型;Cytb基因全序列共有10个多态性位点,7种单倍型。Cytb基因的1146个碱基编码381个氨基酸,氨基酸链共有3个变异位点,4种单倍型,厦门群体具有4种单倍型,湛江群体只有1种单倍型。综合Cytb基因和控制区序列,2个条纹斑竹鲨群体共有10种单倍型,其中厦门群体有9种单倍型,湛江群体仅4种单倍型。研究结果表明条纹斑竹鲨在控制区和Cytb基因序列上的遗传多样性均较低,厦门群体的遗传多样性水平高于湛江群体。Genetic diversities of Chiloscyllium plagiosum(Bennett,1830)from Xiamen and Zhanjiang were investigated with mitochondrial control region and cytochrome b(Cyt b)gene sequence analysis.Control region and Cyt b gene fragments from 30 individuals were cloned with PCR method and sequenced.The sequences of the mitochondrial control region,Cyt b gene and tRNAPro gene were obtained.The complete sequences of the mitochondrial control region,Cyt b gene and tRNAPro gene were 69 bp,1 094～1 096 bp and 1 146 bp respectively.tRNAPro gene seemed conservative,without any polymorphism.Among 30 samples,there were 4 polymorphyism sites with 5 haplotypes for control region sequence and 10 polymorphyism sites with 7 haplotypes for Cyt b gene sequence.1 146 bp nucleotide of Cyt b gene encoded 381 amino acids,and the amino acid chain had 3 polymorphyism sites with 4 haplotypes.Samples of Xiamen stock had 4 haplotypes while Zhanjiang stock only 1 haplotype.It was seemed that the genetic diversities in Cyt b and control region from C.plagiosum in Xiamen were comparatively higher than those in Zhanjiang,though both appeared relatively low.国家自然科学基金项目(40776083,40876080);; 厦门市科技项目(3502Z20063022

Progress of studies on chromosome of Chondrichthyes

在各类脊椎动物中,软骨鱼类是开展染色体研究最少的类群。迄今为止,文献共报道了70种软骨鱼的核型,仅占现生838种软骨鱼类的8.35%,包括31种鲨类,37种鳐类和2种全头类。已报道的软骨鱼类二倍体染色体数为52~104(巴西双鳍电鳐二倍体染色体数为28例外),常存在微染色体。在不同的分类阶元,相对原始的软骨鱼类具有较多的染色体数,端部和亚端部着丝粒染色体较多,多有微染色体。软骨鱼类染色体进化趋势表现为个体染色体数目的减少,中部和亚中部着丝粒染色体数目的增多,并伴随微染色体的消失。软骨鱼类是核DNA含量较大的脊椎动物。已报道144种软骨鱼类的核DNA含量,其变化较大,为3.0~34.1 pg/N,全头类的核DNA含量最小,角鲨目和扁鲨目的核DNA含量最大。近年来,在软骨鱼类染色体的C带、核仁组织区(NOR)染色、限制性内切酶显带、特异DNA探针如端粒序列和短散布重复序列(SINE序列)的荧光原位杂交等方面取得了较大进展。现代分子生物学技术也被用于一些软骨鱼类的基因组研究,在重复DNA序列、随体DNA家族和微卫星位点等方面均取得一些成果。The chromosome of Chondrichthyes is the least investigated among vertebrates.The karyotypes of 70 out of 838 known species(8.35%) have been described,including 31 Selachomorpha,37 Batomorpha and 2 Holocephalian species.The diploid chromosome number ranges from 52 to 104,with the exception of Narcine brasiliensis which is 28,and microchromosomes are often present.The most primitive species in the different taxa have high diploid chromosome numbers,with many telocentric and acrocentric elements,and most of then have microchromosomes.The general trend in all groups seems to be a progressive increase of the metacentric and submetacentric chromosome number in the most specialized species,which is followed by the loss of the microchromosomes.Chondrichthyes have the larger genome sizes among vertebrates.Nuclear DNA contents of 144 chondrichthian species have been described.In the whole class,the species examined vary greatly in genome size,from 3.0 to 34.1 pg/N,the lowest values have been observed in holocephalans,while the highest values in Squaliformes and Squatiniformes.In recent years,studies on chondrichthian chromosome have been improved by C-banding,nucleolar organizer regions(NOR) staining,restriction enzymes in situ digestion and fluorescent in situ hybridization(FISH) with specific DNA probes,such as telomeric sequence and short interspersed repetitive elements(SINE) sequences.The genomes of several chondrichthian fish have also been studied by up-to-date molecular techniques,especially as regards the repetitive DNA sequences,satellite DNA family and microsatellite loci.福建省教育厅科技项目(JA03136

Studies on Growth and Feeding of Larva and Juvenile of Epinephelus coioides

于2003~2004年对人工培育的斜带石斑鱼(Epinephelus coioides)仔鱼、稚鱼和幼鱼的生长和摄食进行了研究.在水温28.5~31.0℃,盐度31.4~34.3条件下,初孵仔鱼经39 d培育变态为幼鱼.全长(L/mm)与日龄(D/d)的关系式为L=2.039 8e0.076 7D;体质量(M/mg)与日龄(D/d)的关系式为M=0.065 8e0.252 8D;全长(L/mm)和体质量(M/mg)的关系式为M=0.006 5L3.267 3.对170尾仔、稚、幼鱼的解剖观察结果表明,摄食率达95.88%,饱食率达77.65%.饱食量(F/mg)与体质量(M/mg)呈直线相关,F=0.043 3M-0.003 9,大多数仔稚鱼在30 min内可以饱食.仔鱼对轮虫的消化时间为1~2 h,稚鱼对卤虫无节幼体和桡足类的消化时间分别为1.5~3 h和2~4 h.斜带石斑鱼仔稚鱼的摄食强度具有明显的昼夜节律性,仔鱼白天摄食、晚上不摄食,前期仔鱼在8:00和18:00摄食量较大,后期仔鱼在8:00和16:00摄食量较大,稚鱼昼夜均摄食,摄食高峰期出现在中午12:00.Growth and feeding of larva and juvenile of Epinephelus coioides were studied during 2003 and 2004.The larvae developed to young fish 39 days after hatching under the conditions of temperatures of 28.5~31.0℃ and salinities of 31.4~34.3.The relationship between the total length(L/mm) and day age(D/d) was counted to be L=2.039 8e~(0.076 7D),the relationship between the body mass(M/mg) and day age(D/d) could be expressed to be M=0.065 8e~(0.252 8D),and the relationship between the total length(L/mm) and body mass(M/mg) was calculated to be M=0.006 5L~(3.267 3).Based on the determination of 170 individuals,the percentage of stomach with food was 95.88% in the experimental conditions,and the percentage of stomach full with food was 77.65%.Amount of food in full stomach(F/mg) and the body mass(M/mg) could be expressed to be F=0.043 3M-0.003 9.Most of larvae and juvenile could spend less than 30 min on feeding from empty to full in stomach,the larvae spend 1~2 h on digesting rotifers from full to empty in stomach,and the juvenile spend 1.5~3 h on digesting artemia nauplii and 2~4 h on digesting copepods from full to empty in stomach.Feeding intensity was obviously different during day and night,the higher feeding intensities of early-stage larvae were at 8:00 and 18:00,while the higher feeding intensities of lately-stage larvae were at 8:00 and 16:00,and the higher feeding intensity of juvenile was at 12:00.It turn out that larvae were feeding only on day,not at night.863计划(2003AA603011);; 福建省重大科技项目(2002N009)资

适用于低速UWB的多径接收算法改进

叉指数优化选择是传统MMSE-Rake（最小均方差Rake接收机）算法的重要组成部分,广泛应用于UWB（超带宽）Rake接收机中。为了提高在低速传输条件下UWB系统对多径信号接收的快速识别能力,提出了一种基于优化抽头系数的MBER（最小误比特率）改进算法,该算法可在不降低多径分辨率的前提下,通过简化Rake叉指数实现快速定位。仿真结果表明,在低速CM3（NLOS信道）和CM4（特殊情况下NLOS信道）多径模拟信道传输条件下,改进后的算法在性能上优于传统MMSERake算法,不仅降低了Rake接收机的复杂度,还提高了信号接收的实时性