波浪作用下悬移质泥沙运动的两相流数值模型

该文采用基于水沙两相紊流的数值模型对波浪作用下的悬移质泥沙运动进行研究. 基本方程中将水相和颗粒相通过相间作用力进行耦合, 合理地考虑了相间相对运动的影响. 数值计算方法为有限体积法, 对流项处理利用了三阶精度的QUICK格式, 离散方程组求解采用的是TDMA迭代方法. 计算得到的悬移质泥沙垂线时均计算值与不同尺度的水槽实验数据吻合很好, 表明数学模型及其计算方法对于低浓度水沙两相问题是合理的. 该研究还探讨了悬沙浓度、泥沙沉降速度以及各种相间作用力随时间的分布规律

减压直流非转移电弧及等离子体射流波动特性研究

实时测量了减压直流纯氩等离子体的弧电压和射流高温区的瞬时离子饱和电流. 结合射流高温区的瞬时形貌, 探讨了在真空室压力500~10000 Pa条件下电弧及等离子体射流的波动特性. 结果表明:当气流量较小和真空室压力较低时, 射流流场呈现较好的稳定性. 随着气流量和真空室压力增加, 弧电压出现高频脉动, 射流能量分布的空间和时间稳定性逐渐变差, 离子饱和电流信号变得紊乱;即使由于电源特性引起电弧功率300 Hz的波动幅度高达35%, 依然能够产生流场较稳定的等离子体射流;静电探针检测等离子体射流的瞬时离子饱和电流可作为了解射流波动特性的一种快速响应方法.

粗枝云杉( Picea asperata Mast.)天然群体的遗传变异

西南地区在我国的经济发展和生态环境建设中占重要地位，但也是我国生态环境最脆弱的地区之一，生态系统退化，生态功能减弱，严重制约着西南林业的可持续经营与发展。本项目采用DNA 分子标记SSR 研究不同生境条件下粗枝云杉群体的遗传变异及其时空分布格局，考察遗传变异与复杂的山地生态环境间的潜在联系，系统地揭示粗枝云杉天然群体与环境系统相互作用的生态适应与分子进化机制。粗枝云杉适应性强，生长迅速，在植树造林和工业用材方面占有重要地位，研究成果可为中国西南部亚高山天然林的可持续经营及退化生态系统的恢复与重建提供理论依据和科学指导。主要研究结果如下： 1. SSR 位点变异丰富，等位基因频率的分布格局多样。7 个SSR 标记全是多态位点，每位点的等位基因数变化范围为13~24，平均为19.9 个。SSR 位点的等位基因片段长度范围变化较大。73.1%的等位基因变异遵循逐步突变模型(SSM)而发生1 个重复基元的变化，22.3%和4.6%的变异分别按两阶段突变模型(TMP)发生1 个重复基元以上的变化和在SSR 位点侧翼区发生1 个碱基变化的插入-删除事件。 2. 粗枝云杉拥有中等偏高水平的遗传多样性和相对大的群体间遗传分化。通过分析代表10 个群体的250 个个体在7 个SSR位点的变化，调查了源自中国西南山区的粗枝云杉的微卫星变异。相当高的遗传多样性和强烈的群体分化发生在粗枝云杉中， 其群体平均Nei's 期望杂合度为0.707 ， 群体间遗传距离为0.121~0.224(FST)和0.100~0.537(RST)。然而，群体间遗传距离与地理距离之间无相关性，从而排除了简单的距离分离模式并暗示迁移不是影响粗枝云杉遗传变异格局的主要因素。事实上，使用私有等位基因估算的基因流数量非常低，仅等于0.753。等位基因置换检验(Allele permutation tests)揭示逐步突变及遗传漂变都对群体间分化有贡献。另外，在多数位点检测到显著的群体间遗传差异，这个结果说明自然选择，假设通过环境压力，是引起粗枝云杉微地理分化的主要因素之一。根据SSR基因型，250 个粗枝云杉个体的70%被正确地归类入其各自的来源群体，结果表明微卫星(SSR)对区分来自中国不同生态地理位点的粗枝云杉基因型是有效的。 3. 在SSR、RAPD 和AFLP 位点，显著的群体间遗传结构被发现的，但三种标记间遗传分化程度和群体遗传关系有差异。利用来自10 个群体的247 个个体，我们报告了关于样本粗枝云杉群体间遗传关系的总体看法。根据各自对评价遗传关系的信息能力和适用性，SSR、RAPD 和AFLP 标记被选用，三种技术非常有效地区别这些基因型。使用的SSR、RAPD 和AFLP 标记分别估计平均Dice 相似性系数。Mantel 检验产生显著但相对低的共表型适合度(RAPD = 0.63£AFLP = 0.60和SSR = 0.75)。比较三种标记系统，RAPD 和AFLP 共表型指数相对高地相关(r =0.59)，而RAPD 和SSR 及SSR 和AFLP 之间的相关系数分别是0.53 和0.35。所有系统树，包括不同标记资料结合获得的系统树，反映了多数群体依据它们的地理条件而成某种特定关系。结果暗示单个或结合标记系统能用来深入洞察粗枝云杉遗传研究，并且不同标记系统合并资料能提供更可靠的信息。 Southwestern region plays an important role in economic developmentand ecological construction in China. Yet, it is also one of the weak regionsof ecological environment in China with degraded ecosystem and imperfectfunction, which restricts the sustaining management and development ofsouthwestern forestry. The genetic variation and spatial distribution patternof P. asperata populations originating from different habitats wereinvestigated using SSR molecular markers in this study. The correlationsbetween genetic variation and ecological and environmental conditionswere detected, and the interaction between P. asperata populations andenvironmental system and the mechanism of ecological adaption -molecular evolution were revealed. Given the significant ecological andeconomic roles of the fast-growing and wide-adaptive species in reforestation and production of pulp wood and timber, the study couldprovide a strong theoretical evidence and scientific direction for thesustaining management of subalpine natural forest, and the afforestationand rehabilitation of degraded ecosystem. The results are as follows: 1. The genetic variation at SSR loci was abundant and the distributionof allelic frequencies was uneven. All seven loci were polymorphic, and thenumber of alleles per locus varied from 13 to 24 with a mean valueequaling 19.9. The allele sizes at SSR loci were found to vary widely.73.1% of allelic variation followed stepwise mutation model (SSM) whichresults increase or decrease by one repeat type, and 22.3% and 4.6% wereresulted from two-phase mutation model (TMP) with allele size varying bymore than one repeat type and from insertion-deletion events in theflanking regions at SSR loci with a single basepair changing, respectively. 2. P. asperata possessed a moderate to high level of genetic diversityand considerable genetic differentiation. Microsatellite variation of P.asperata. originating from the mountains of southwestern China wasinvestigated by analyzing variation at seven SSR loci in 250 individualsrepresenting ten populations. A fair degree of genetic diversity and strongpopulation subdivision occurred with the mean gene diversity (H) of 0.707,and genetic distances among populations varying between 0.121 and 0.224(FST) and between 0.100 and 0.537 (RST). However, inter-populationgenetic distances showed no correlation with geographic distances between the population sites. This ruled out a simple isolation by distance modeland suggested that migration does not have a great impact. In fact, theamount of gene flow, detected using private alleles, was very low, equalingonly 0.753. Allele permutation tests revealed that stepwise-like mutations,coupled with genetic drift, could contribute to population differentiation.Moreover, significant genetic differences between populations weredetected at most loci. The results indicate that natural selection, presumablythrough environmental stress, may be one of the main factors causingmicro-geographical differentiation in the genetic structure of P. asperata.Based on SSR genotypes, 70% of the 250 individuals were correctlyclassified into their sites of origin. This suggests that microsatellites (SSRs) are effective in distinguishing genotypes of P. asperata originating fromdiverse eco-geographical sites in China. 3. Using a set of 247 individuals from ten P. asperata populations wereport an overview on the genetic relationship among the sampled P.asperata populations. RAPD, AFLP and SSR were used in terms of theirinformativeness and applicability for evaluate relationship and all threetechniques discriminated the genotypes very effectively. Mean Dicesimilarities coefficient were estimated using RAPD, AFLP and SSR,respectively. The Mantel test resulted in a significant but relatively low fit(RAPD = 0.63, AFLP = 0.60 and SSR = 0.75) of cophenetic values.Comparing the three marker systems to each other, RAPD and AFLP cophenetic indices were highly correlated (r = 0.59), while correlationcoefficient between RAPD and SSR was r = 0.53 and between SSR andAFLP was r = 0.35. For all markers a relatively high similarity indendrogram topologies was obtained although some differences wereobserved. All the dendrograms, including that obtained by the combineduse of all the marker data, reflect some relationships for most of thepopulations according to their geographic conditions. The results indicatethat single or combined marker system could be used to insight into geneticstudy in P. asperata and the combined data of different marker systems canprovide more reliable information.

不同小麦品质类型与生态环境关系的研究

小麦（Triticum aestivum L.）是世界上种植面积最大，总产量最高，食物加工种类最丰富的粮食作物，占世界人口35 ％－40 ％的人们以此为主要食物。因此小麦产量的高低和品质的优劣直接影响人们对食物需求的安全和满意程度，也影响着人类的营养平衡以及面粉和食品加工业的发展。随着生活水平的提高，人们对于小麦的品质越来越重视。培育优质专用小麦新品种，制定优质专用小麦品种品质生态区划，从而在不同程度上实现小麦的区域化种植和产业化经营具有重要的意义。 影响小麦品质的因素主要是遗传因素和环境因素，其中环境因素又包括各种自然生态因素和人为因素。研究表明，小麦品质的环境间的差异大于品种间的差异，气候条件是影响小麦品质的最重要的因子，小麦品质的地域间的差异反映出了小麦的品质区域分布规律。为了满足市场对不同品质小麦的需求，对小麦进行区域化研究具有重要的理论和现实意义。本研究结合四川的地理、气候特点，研究不同品质类型与生态环境的关系，为在复杂的生态环境内进行品质区划提供依据。 本研究首先根据四川省小麦种植区域的生态特点，在四川省多个典型生态区：川南丘陵的荣县、川西南高原的西昌、川西平原的双流布点种植，采用的小麦试验材料为不同品质类型：中筋小麦川育12、川育14、川育16由本所提供；弱筋小麦川麦32和强筋小麦川麦36由四川省农科院作物所提供。通过研究品质性状与品种及各个生态因子包括地点、土壤土质差异等的关系，明确不同生态环境中适宜种植的小麦品种类型，强筋小麦、中筋小麦更适合于在荣县、双流地区种植，弱筋小麦更适合于在西昌地区种植，为品种品质区划奠定基础。 其次，选择了本课题组育成的稳定中间品系，对其品质性状SDS沉降值进行了多年测定。分析了品质性状SDS沉降值与多种气候因子的相关性，结果表明SDS沉降值与日均温、日照时数成正相关，与降水量成负相关，为品质育种提供了理论依据。 此外，以中筋小麦新品种小麦川育14为材料，应用三元二次正交旋转回归模型设计试验，研究主要栽培因子播期、密度和施肥量对产量的影响，并建立函数模型。经计算机模拟寻优，筛选出了高产高效栽培组合措施，并确定了置信域。结合四川省不同的地理情况，在平原和丘陵地区分别进行实验，并各自建立了高产高效栽培组合措施，为川育14品种的推广提供了理论指导。 Wheat is one of the most important crops in the world. About 35%-40% people all over the world, take the wheat as their most important food. So the quality, as well as the quantity of the wheat makes a direct effect on people’s demands of food and their satisfaction. It also effects on human’s healthy, and the development of the Food processing industry. With the development of the living standard, people pay more attention to the quality of wheat. So, we set a special ecology zoning for wheat. It is significant to carry out planting the wheat in special zoning in varying degrees. The main factors affecting wheat quality are heredity and environment including many ecological factors and the factors in cultivation. As to the quality，the difference between ecology and cultivation is more important than the difference between special wheat. In so many factors, climate is the most important one. From the difference in quality between different zones，we can conclude the rule of distribution abort quality of wheat. Finding out the intersection of numerous wheat not only can meet the demand of food production，but also has important signification in theory and realism。In our research, according to the complex geography in Sichuan province, we study the relationship between numerous kinds of quality characters in wheat and the ecology. So, we can set a foundation for more research. In this research, firstly, we plant wheat in some typical ecological regions of SICHUAN province: RONGXIAN（south of SC）、XICHANG（south of SC）, SHUANGLIU(west of SC). The materials of the experiments: ChuanYu12, ChuanYu14, ChuanYu16(from our institute), Chuanmai32, Chuanmai36 (from the Chinese academy of agriculture sciences of Sichuan. Through the research on the relationship between the quality of wheat and those ecology factors, we can make a definition that which area is perfect matched with which kind of wheat. And it can satisfy the demand of people. Secondly, select many sorts of wheat from our research group. All of them are selected and bred more than 3 years(2003-2005). And we make every-year determination as well. We’ve gotten SDS value from those 9, and various data on factors of climate. We also got to know the relation ship between those numbers. Thirdly, use Chuanyu14 as material, the mathematical model of the relation between the production of wheat and main agricultural measures such as date, density and fertilizer. The model was established by association of three elements two return, rotate and regression. We set a suitable model and get a suitable method which can make high harvest. Based on various kinds of geographical regions in Sichuan province, we set different models which can be used in plain and hill. So, we can plant Chuan Yu 14 in Sichuan province under the result in research.

Fusion dynamics of symmetric systems near barrier energies

Within the framework of the improved isospin-dependent quantum molecular dynamics (ImIQMD) model,he fusion dynamics of symmetric reaction systems are investigated systematically. Calculations show that the number of nucleon transfer in the neck region is appreciably dependent on the incident energies, but strongly on he reaction systems. A comparison of the neck dynamics is performed for the symmetric reactions 58Ni+58Niand 64Ni+64Ni at energies in the vicinity of the Coulomb barrier. An increase of the ratios of the neutron to proton in the neck region at initial collision stage is observed and obvious for the latter system, which reduces the fusion barrier of two colliding nuclei. The distribution of the dynamical fusion barriers and the fusion excitation functions are calculated and compared with the available experimental data.

N-乙酰半胱氨酸对碳离子照射小鼠急性损伤的保护效应

探讨了N-乙酰半胱氨酸(N-acetylcysteine,NAC)对12C6+离子照射小鼠损伤的保护效应及可能的作用机制。预先给予昆明小鼠NAC(200mg/kg),后进行12C6+离子束4Gy的单次全身照射。照射后2h处死小鼠,取肝、肺组织,用化学法检测组织中超氧化物岐化酶(Superoxide dismutase,SOD)的活性,谷胱甘肽(Glutathione,GSH)含量及脂质过氧化产物丙二醛(Malondialdehyde,MDA)水平;用碱性单细胞凝胶电泳法检测DNA单链断裂;用流式细胞术检测组织细胞凋亡率。与照射对照组相比,提前给予NAC可极显著地减轻12C6+离子导致的肝、肺组织中DNA断裂(p<0.001)和细胞凋亡(p<0.001),并显著地提高组织中GSH的含量;NAC还明显地抑制了肺组织中碳离子辐照所致的MDA水平增高(p<0.01)并显著地诱导了组织中SOD活性的升高(p<0.01)。提示NAC可通过抵御组织内的氧化作用,合成、补充GSH的含量,阻止DNA链的断裂和细胞的凋亡,实现对碳离子辐照损伤的保护效应。

MAPK途径与细胞的辐射应答

MAPK信号转导途径在细胞辐射应答中起着重要作用,ERK,JNK,P38 MAPK和大MAPK 4条不同的MAPK通路在受辐射细胞中扮演着不同角色,它们的协调控制作用决定着细胞受辐照后的命运。描述了辐射应答中的这4条不同的MAPK途径,并讨论了这些途径在辐射应答中的作用。

并行设备总线嵌入式控制系统设计

为了对物理实验装置的远程监控和访问,将采用32位内核芯片技术结合CPLD逻辑时序编程来设计3U VME设备总线系统。S3C4510B是三星公司针对网络应用而设计的CPU,本身带有100Mbps网络控制器,而由于Clinux系统拥有完善的TCP/IP协议,因此二者的结合为用户提供了强大的网络服务功能。该系统利用嵌入式网络和并行总线技术可稳定可靠地实现数据的快速获取与给定。

~(12)C~(6+)离子诱导TNFα基因在SMMC-7721细胞中的表达

目的用Polyfect转染试剂将重组质粒pEgr-TNFα转染人肝癌细胞SMMC-7721,研究该重组质粒经12C6+离子作用后在细胞中的表达。方法用ELISA方法检测TNFα的蛋白表达,用RT-PCR方法检测TNFα转录水平的变化。结果转染pEgr-TNFα后在SMMC-7721细胞中TNFα的蛋白表达量为2·06ng/ml,2Gy12C6+离子照射后,表达量增高为2·11ng/ml,明显高于未转染组和转染空载体组;RNA转录水平也明显增高,2Gy12C6+离子照射后增高更明显。结论12C6+离子联合重组质粒pEgr-TNFα,在被转染的SMMC-7721细胞中表达量明显增高。

辐射基因治疗在肿瘤治疗中的研究现状

目前肿瘤基因治疗尚存在许多问题,距临床应用还有相当的距离,但是在传统的放疗、化疗和手术治疗的基础上,辐射与基因治疗的有机结合在肿瘤治疗中却显示出可喜的前景。综述了近年来这一领域的研究进展,探讨了这一疗法对肿瘤治疗的应用前景。