溃坝流的光滑粒子法模拟

用光滑粒子法模拟几种情况的溃坝流动,对坝外无水和有水的情况进行二维模拟,对坝外有立柱的情况进行三维模拟.流动控制方程采用雷诺平均方程模拟溃坝流动的湍流效应,采用混合长度形式的涡粘模式对控制方程进行封闭,推导其相应的光滑粒子形式的方程.模拟结果表明,数值模拟的流动特征与实验结果符合得非常好,说明发展的光滑粒子法有效.

加压条件下甲烷/空气预混火焰可燃极限的微重力实验研究

本文成功搭建了适用于中国科学院力学研究所国家微重力实验室(NMLC)落塔的高压对冲火焰实验系统, 并首次开展了微重力条件下加压对冲火焰实验, 测定了一定张力条件下甲烷/空气层流预混火焰的熄灭极限. 实验结果表明, 随着压力的增高, 甲烷/空气混合气体的可燃极限呈先增后降的非单调变化趋势, 峰值发生在0.4 MPa左右. 浮力对加压下微弱火焰熄灭极限的影响明显, 在常重力条件下, 相同张力下的熄灭极限较微重力条件下的偏大, 峰值出现的压力略低. 微重力条件下的实验结果与使用CHEMKIN的数值模拟的结果相当一致.

青藏高原东缘青杨（Populus cathayana Rehd.）遗传多样性研究

青杨（Populus cathayana Rehd.）是青杨派杨树的主要树种之一，为我国特有乡土树种，其主要分布区之一是我国的青藏高原，集中分布地带在甘肃省中部及青海省东部，四川省西北部岷江上游和松潘等地区。本研究以青藏高原东缘青杨天然分布区的6个群体143个个体为材料，用AFLP、SSR和叶绿体SSR分子标记分析青杨天然群体的遗传多样性，分析其遗传结构和分化，比较6个群体间遗传多样性的高低和群体间的遗传关系。旨在为青杨基因资源评价、保护与保存、遗传改良策略制定等提供科学理论依据。通过以上研究，得出如下主要研究结果： 1 AFLP分子标记研究结果 采用4对选择性引物对6个青杨天然群体143个个体进行分析，扩增谱带分析共检测到175个位点，其中173个位点表现为多态，多态位点百分率高达98.9%。从整体上表现出较高的遗传多样性，Nei’s基因多样度(h)水平为0.306。从青杨天然群体位点分布来看，有高达20%的位点（32位点）为群体所特有，仅有9.14%的位点（16位点）在所有群体中存在。群体间的遗传分化极大，所有遗传变异中，有48.9%的遗传变异存在于群体间。在个体群丛（Individuals cluster）和主坐标（PCO analysis）分析中，青杨各群体未呈现任何地理模式，Mantel检测也显示各群体间遗传距离与地理距离无明显相关。研究认为，由于地理和空间上大尺度的隔离和地形地貌复杂使得群体间无法进行基因交流，导致群体间遗传分化极大，另外各群体在不同的选择压力下，经历各自独立的进化历程，这些都可能导致群体间遗传距离与地理距离的不相关。 2 SSR分子标记研究结果 在SSR分析中，7个位点在6个青杨天然群体143个个体中共检测到79个等位基因，每位点检测到的等位基因数在5-16之间，平均11.3个，总体上多态位点百分率达100%。平均观察杂合度和期望杂合度分别为0.792和0.802。Hardy-Weinberg平衡检验表明青杨大部分群体都处于非平衡状态，群体大部分位点都是偏离哈迪-温伯格平衡（76.3%），只有23.7%的测验满足哈迪-温伯格平衡。分析青杨天然群体内和群体间的遗传变异，基因分化系数（GST）为0.373，即有62.7%的遗传变异存在群体内，37.3%的遗传变异存在群体间。群体内的遗传变异高于群体间水平。根据各群体遗传距离UPGMA聚类分析，有来自相临分布区、近似气候类型的群体聚在一起的趋势，但Mantel检测反映遗传距离与地理距离间并无明显相关性。 3 cpSSR分子标记研究结果 分析来自青藏高原东缘6个青杨天然群体，所用cpSSR引物中有5对cpSSR引物（CCMP2、CCMP5、SCUO01、SCU03、SCU07）都表现较高的多态性，单个引物检测的片段数都在4以上。5对cpSSR引物共检测片段数26个，组成了12种叶绿体DNA单倍型。各群体的单倍型分布和频率有较大差异，群体单倍型多样性范围为0-0.4926，TS、JZ、PW和SHY群体单倍型多样性高于QHY和LED群体水平。本研究发现，分布在青藏高原东缘的青杨天然群体，群体间不存在共享的单倍型，各群体间存在极大的遗传分化（GST=0.9223）。从青藏高原东缘地区经历的地质历史事件来看，第四纪的冰期气候变迁可能是造成青杨现今遗传结构模式的主要因素之一。根据单倍型在各群体的分布情况，进行青杨群体聚类分析结果，各群体无明显的分组现象，青杨各群体也未呈现任何清晰地理模式。 由于不同分子标记在对群体遗传多样性检测能力与效率上存在差异，所以三种标记检测的青藏高原东缘青杨天然群体遗传多性水平也不尽一致，但在与用同种方法检测其它物种或同一物种不同种源群体比较，三种分子标记方法都揭示了青藏高原东缘青杨天然群体具有中等偏上的遗传多样性水平。结果分析表明，群体间遗传分化极大，这是由于青杨天然群体分布于青藏高原东缘，既有高原又有高山峡谷，由于地理和空间上大尺度的隔离和地形地貌复杂导致了基因流物理上的阻隔。三种分子标记研究结果经Mantel分析检测，遗传距离与地理距离之间都无明显相关性。较为一致的解释是，青杨分布区域地理和空间上大尺度的隔离和和地形地貌复杂导致群体之间不存在均匀扩散现象，另外各群体在不同的选择压力下，经历各自独立的进化历程，这些都可能导致群体间遗传距离与地理距离的不相关。 The wide geographical and climatic distribution of P. cathayana Rehd. indicates that there is a large amount of genetic diversity available, which can be exploited for conservation, breeding programs and afforestation schemes. The results are as follows: 1 Research results of AFLP genetic diversity In present study, genetic diversity was evaluated in the natural populations of P. cathayana originating from southern and eastern edge of the Qinghai-Tibetan Plateau of China by means of AFLP markers. For four primer combinations, a total of 175 bands were obtained, of which 173 (98.9%) were polymorphic. Six natural populations of P. cathayana possessed different levels of genetic diversity, high level of genetic differentiation existed among populations (GST=0.489) of P. cathayana. Individuals cluster and PCO analysis based on Jaccard’s similarity coefficient also showed evident population genetic structure with high level population genetic differentiation. The long evolutionary process coupled with genetic drift within populations, rather than contemporary gene flow, are the major forces shaping genetic structure of P. cathayana populations. Moreover, there is no correspondence between geographical and genetic distances in the populations of P. cathayana, seldom gene exchange among populations and different selection pressures may be the causes. Our finding of different levels of genetic diversity within population and high level of genetic differentiation among populations provided promising condition for further breeding or conservation programs. 2 Research results of SSR genetic diversity In this study, the genetic diversity of P. cathayana was investigated using microsatellite markers. In a total of 150 individuals collected from six natural populations in the southeastern part of the Qinghai-Tibetan Plateau in China, a high level of microsatellite polymorphism was detected. At the seven investigated microsatellite loci, the number of alleles per locus ranged from 5 to 16, with a mean of 11.3, the observed heterozygosities across populations ranged from 0.408 to 0.986, with a mean of 0.792, and the expected heterozygosities across populations ranged from 0.511 to 0.891, with a mean of 0.802. The proportion of genetic differentiation among populations accounted for 37.3% of the whole genetic diversity. The presence of such a high level of genetic diversity could be attributed to the features of the species and the habitats where the sampled populations occur: The southeastern part of the Qinghai-Tibetan Plateau is regarded as the natural distribution and variation center of the genus Populus in China. Variation in environmental conditions and selection pressures in different populations, and topographic dispersal barriers could be factors associated with the high level of genetic differentiation found among populations. The populations possessed significant heterozygosity excesses, which may be due to extensive population mixing at the local scale. The cluster analysis showed that the populations are not strictly grouped according to their geographic distances but the habitat characteristics also influence the divergence pattern. In addition, we suggest that population SHY should be regarded as an ecologically divergent species of P. cathayana. 3 Research results of cpSSR genetic diversity Genetic diversity of six natural populations of P. cathayana originating from the southeastern part of the Qinghai-Tibetan Plateau in China was studied by use of cpSSR markers. Based on 5 pairs of polymorphic primers screened from 12 pairs of primers, twenty-six different length fragments and twelve different kinds of haplotypes were reduced in 143 samples. There were significant variant haplotypes among the populations．There were no shared haplotypes found among populations, analysis of molecular variance indicated that a high proportion of the total genetic variance was attributable to variations among populations (92.23%). The pattern of genetic structure which is associated with spatial separation, variation in environmental conditions and selection pressures in different populations, is also the result of geological historical factor. A molecular phylogenetic tree based on the 12 haplotypes showed that the populations are not strictly grouped according to their geographic distances.

同源四倍体与二倍体水稻的遗传差异及产量、品质性状研究

本文以中国科学院成都生物研究所培育的同源四倍体水稻和二倍体水稻为材料，进行遗传差异及产量、品质性状的研究：1、以二倍体水稻为对照，研究了同源四倍体水稻在2004 年和2005 年的结实情况。结果同源四倍体的花粉育性、结实率均不同程度下降，尤其低代材料更是大幅度下降。F 检验表明，同源四倍体不同个体间的各产量性状均差异显著，说明其具有很大的遗传改良潜力。从1996 年到2005 年对部分同源四倍体水稻进行了连续选择改良，T 检验表明经过9 年的选择改良，其结实率显著提高。本文还对同源四倍体水稻各产量性状间的相关性进行了分析,结果结实率与花粉育性、穗着粒数、穗实粒数极显著相关；理论产量与花粉育性、有效穗数、穗着粒数、穗实粒数、结实率及千粒重极显著相关。i2、用(CT)n 微卫星标记和PCR-Acc Ι分子标记对40 份同源四倍体和14 份二倍体水稻Wx 基因进行研究。结果，(CT)n 微卫星标记检测，Wx 基因呈Wx1、Wx2 和Wx3 3 种多态性；PCR-Acc Ι 检测，Wx 基因表现为G-型和T-型。测定稻米直链淀粉含量(AC)、胶稠度(GC)和糊化温度(GT)，并探讨其与Wx 基因的关系，结果，二倍体和同源四倍体水稻均存在：Wx 基因型相同，AC 差异较小，Wx 基因型不同时，AC 差异较大，Wx1 基因型品种AC 最高， Wx2 基因型品种AC 次之，Wx3 基因型品种AC 最低；基因型相同时，同源四倍体AC 低于二倍体；同源四倍体与对应二倍体间，Wx 基因型相同时，AC 差异很小；而Wx 基因型发生变异时，AC 差异很大。同时，进行相关性分析，结果二倍体和四倍体水稻均存在AC、GC 与Wx 基因密切相关；而GT 与Wx 基因相关不显著。综合分析，(CT)n微卫星标记与PCR-Acc Ι 分子标记检测的相关系数为0.842，呈极显著正相关，可以将其结合起来进行同源四倍体新品种的选育和改良。3、利用RAPD 技术，对同源四倍体和二倍体水稻的遗传差异进行分析。17条引物在同源四倍体中扩增出178 条带（PPB＝81.5%），在二倍体中扩增出173条带（PPB＝76.3%）；同源四倍体和二倍体的Shannon 遗传多样性指数分别为0.4848 和0.4679，多态信息量分别为0.3301 和0.3216，遗传距离分别为0.3572和0.3460；同源四倍体与其对应二倍体间遗传距离为0.1914-0.4633，平均为0.2914。表明同源四倍体的遗传多样性高于二倍体，且同源四倍体与其二倍体之间存在较大的遗传差异，这些将为水稻品种改良和新品种选育提供科学依据。上述产量、品质性状及遗传差异分析的结果，不仅有利于加快同源四倍体水稻的遗传改良进程，而且为进一步研究、利用同源四倍体水稻奠定了初步基础。 AbstractStudy on genetic diversity, yield characters and quality traitsof autotetraploid and diploid riceLiu Yuhua (Botany)Directed by Associate Prof. Tu ShengbinIn this study, diploid and autotetraploid rice, which were cultivated in ChengduInstitute of Biology were analyzed in genetic diversity, yield characters and qualitytraits.In the study, 2 diploid and 29 autotetraploid rice(2n=4x=48) materials, including4 preliminary and 25 advanced generation, were investigated for yield characters.Compared with diploid check, the pollen fertility and seed set of autotetraploiddeclined dramatically, especially in preliminary generation. F-test indicated that therewere remarkable differences among different varieties, showing that autotetraploidmaterials had strong potential for improvement. From 1996 to 2005, someautotetraploid rice had been selected and improved. T-test showed that seed setincreased obviously. The relationships among yield characters of autotetraploid ricewere analyzed. Seed set was strongly correlated with pollen fertility, total grainnumber per panicle and productive grain number per panicle; theoretical yield wasstrongly correlated with pollen fertility, productive panicle number per plant, totalgrain number per panicle, productive grain number, seed set and 1000-grain weight.Wx genotypes of 40 autotetraploid rice and 14 diploid rice were tested by usingthe (CT)n microsatellite marker and a cleaved amplified polymorphic sequence(CAPS) molecular marker named PCR-Acc Ι. Three microsatellite alleles wereproduced, i.e. Wx1, Wx2 and Wx3 both in autotetraploid and in diploid rice.Comparatively, PCR- Acc Ι molecular marker produced two genotypes, G-type andT-type for both autotetraploid and diploid rice. In this study, amylose content (AC), gel of consistency (GC) and gelatinization temperature (GT) of rice grain weremeasured and their relationships with Wx alleles were analyzed. The results showedthat variation of AC between autotetraploid and diploid rice was small when they hadthe same Wx genotype. However, variation of AC turned to be large when the Wxgenotypes were different. Actually, AC met the maximum value in Wx1 varieties andWx2 varieties the middle and Wx3 varieties the minimum. And AC was lower inautotetraploid than in diploid. Correlation analysis was done in this experiment. ACand GC of rice grain were probably controlled by Wx gene or other gene whoselocation was strictly linked to Wx gene, while GT of rice was not. The correlationcoefficient between Wx genotypes which revealed by (CT)n microsatellite marker andPCR-Acc Ι molecular marker was 0.842 with significant level. That revealed aconsistent result between the two types of markers. So it was possible to utilize boththe two types of markers to select and promote germplasm of autotetraploid rice.RAPD molecular markers were used to analyze the genetic diversity betweendiploid and autotetraploid rice. 178 repeatable bands were detected through 17 RAPDprimers with percentage of polymorphic bands was 81.5% in autotetraploid rice while173 repeatable bands were detected with percentage of polymorphic bands was 76.3%in diploid rice. According to the measurement of Shannon index, polymorphicinformation content and genetic distance, genetic diversity of autotetraploid was on ahigher level, genetic variation between autotetraploid and diploid rice was relativelyhigh. All these contributed to the genetic selection and improvement in rice breeding.As mentioned above, the results are not only helpful to promote the process ofrice improvement, but also to confirm the basic for further study of autotetraploid rice.

全永磁ECR离子源研究进展

Electron Cyclotron Resonance (ECR) ion source is regarded as the most efficient machine to produce stable multiple charge state ion beams. Because of the special characteristics, all-permanent magnet ECR ion sources have been widely adopted around the world to produce stable ion beams of multiple charge state with good repetition have been widely adopted around the world to produce stable ion beams of multiple charge state with good repetition and high duty factor for compact research platforms and ion beam implanters. In this paper, all-permanent magnet ECR ion sources developed at IMP are presented, and typical parameters and performances are discussed. The high charge state source, LAPECR2, is mainly used to produce intense high charge state ion beams, and the LAPECR1 source is designed to produce intense ion beams of medium and low charge state. An improved LAPECR1-M is specially designed to produce heavy metal ion beams of low charge state. These ECR ion sources have been adopted by different experimental terminals at IMP and, with their nice performance, many experimental studies could be possible. 中文文摘：ECR(电子回旋共振)离子源是产生稳定的强流多电荷态离子束流最有效装置。全永磁ECR 离子源因其独特的特点为很多中小型多电荷态离子束流实验平台与离子注入机等系统所采用，为后者产生重复性好、稳定性强的多电荷态离子束流。本文着重论述了中国科学院近代物理研究所研制的几台全永磁多电荷态ECR 离子源及其特性与典型性能，如能产生强流高电荷态离子束流的高性能全永磁离子源LAPECR2，能产生强流中 低电荷态离子束流的LAPECR1，能产生多电荷态重金属离子束流的LAPECR1-M 等。这些性能稳定的离子源为提高近代物理研究所相关试验平台的性能提供了关键的束流品质保障。

全永磁ECR离子源研究进展

ECR(电子回旋共振)离子源是产生稳定的强流多电荷态离子束流最有效装置。全永磁ECR离子源因其独特的特点为很多中小型多电荷态离子束流实验平台与离子注入机等系统所采用,为后者产生重复性好、稳定性强的多电荷态离子束流。本文着重论述了中国科学院近代物理研究所研制的几台全永磁多电荷态ECR离子源及其特性与典型性能,如能产生强流高电荷态离子束流的高性能全永磁离子源LAPECR2,能产生强流中低电荷态离子束流的LAPECR1,能产生多电荷态重金属离子束流的LAPECR1-M等。这些性能稳定的离子源为提高近代物理研究所相关试验平台的性能提供了关键的束流品质保障。