Experimental Study on the Exotic Structure of N-12 in RIBLL

We measured the total reaction cross sections of N-12 in Si at 36.2 MeV/u. using Radioactive Ion Beam Line in Lanzhou (RIBLL) with a new method. The reaction target was installed at the intermediate focusing point T1 at RIBLL. This scheme allows us to identify particles before and after the reaction target unambiguously. The total reaction cross section (1760 +/- 78mb) of N-12 in Si is obtained. Assuming that N-12 consists of a core C-11 plus one halo proton, the excitation function of N-12 on the Si and C targets is calculated with the Glauber model and the Fermi-Fermi density distributions. It can fit the experimental data very well. A large diffusion of the protons density distribution supports the halo structure for N-12.

17F和18Ne与质子弹性散射研究

论文讲述了采用逆运动学方法用放射性核束~(17)F和~(18)Ne与质子弹性散射的实验准备、设汁方法、实验情况、实验数据处理过程、理论分析处理和得到的结果。弹性散射测量核敞射的角分布，对位置探测器有很高的要求。在实验的准备阶段，为了对放射性核束的准确定位，研制了位置分辨为lITlm的高位团置分辨的PPAC。山于质予的穿透能力很强，在半导体硅探测器中的能损很小，实验前，刘。测量反冲质子的探测器PSSD在低能量沉积下的工作情况进行了测试，满足质f位置和I能量测量的要求。实验采用初级束流强度约为80nA能量为45Mev／A的~(20)Ne轰击lmm厚的~9Be，反应产物经过500μm厚的Wedge~(27)Al，通过次级束流线的筛选，得到~(17)F和~(18)Ne和少量的~(16)O束流，其能量分别为17.7Mev／A、16.1Mev／A和14.3Mev／A。然后轰击60μm厚的(CH_2)_n靶。用次级束流线装置的两个焦点处的塑料闪烁体测量放射性核束的时间Tl和T2，根据飞行时间差在相同的磁场条件下来鉴别粒子和得到放射性核束的能量。用靶前的两个PPAC和靶后的一个PPAC来确定放射性核束的入射方向、反应点和出射方向，反冲质子的位置由分布于各实验室系角区的五个PSSD来测定。实验数据处理时，根据放射性核束经过基本相同的飞行路径和磁场条件，用T1和T2测到的飞行时间差来确定放射性核束的能量。将入射到PPAC上的弹核粒子位置，经对宏观几何位置矫正后，来确定弹核粒子的入射方向、反应点位置和出射方向。将PSSD测量到的位置谱经与沉积能量相关的修正因子对位置修正后，确定反冲核在PSSD上的几何位置点，跟PPAC测量确定的靶上的反应点位置结合，确定反冲核的出射方向。测量得到的位置经过空间关系换算，由测量到的弹核入射方向、反应点位置和反冲核出射方向，得到弹性散射的实验室系散射角。累计所有测到的事件得到初始的反冲核实验测量角分布。采用逐个事件的方法，用一事先产生的一系列点组成的数据库模拟探测器边界，事件的几何探测效率进行归一化，得到实际的实验室系散射角分布。用弹核出射角度随反冲核的出射角度的运动学关系鉴别来自靶中的H和C的散射事件。将实验室系角分布转换到质心系下后，再根据弹核粒子数、单位面积靶核数和测量到的事件数，得到实验测量的质的弹性散射微分截面。实验得到的微分截面数据采用零程相互作用的扭曲波玻恩近似理论计算程序DWUCK4序进行光学势拟合计算，选用较准确描述奇异核性质的CH89参数化的光学势为初始的光学势参数，对光学势参数的组成成分进行敏感性分析后，确定参数搜索的顺序，用跟各参数相关联的自动参数搜索程序ABOD进行分析处理。进行光学模型的理论拟合计算时，将计算结果和实验值进行比较，拟合实验数据，求得光学势参数。参数拟合佳度用残差平方和检验(χ~2检验)。得到~(17)F和~(18)Ne与质子弹性散射的光学势参数。根据得到的光学势参数进行折叠模型分析。得到了，1)~(17)F和~(18)Ne实势相互作用均方根半径分别为，_(rF)~(1/2) = 3．239(fm)，_(r_Ne)~(1/2) = 3.317 (fm)。跟相对论平均场计算结果比较分析表明，~(17)F的核物质半径为2.95±0.03fm，~(18)Ne的核物质半径为3.07±0.03fm,~(17)F和~(18)Ne表面的密度要比相对论平均场理论预言的值要大。2)~(17)F和~(18)Ne的自旋轨道耦合相互作用主要作用于核表面区域，这是因为位于核外层的价质子的影响。

TI／AL系统离子束混合研究

本文用100KW Ar~2离子在低温下对Tl/AL薄膜进行了混合束研究。实验试样是在单晶硅上蒸镀约5000A的铝膜，相继再蒸上所需不同厚度的钛膜。用2.0Hev α粒子对注入前后的样品进行了RBS分析。经过仔细的实验数据处理，结果发现：T1／AL界面原子混合量σ~2跟注入剂量φ成线性关系，界面的氧化层对T1／AL界面区原子间的相互混合有一定的影响；在相同注入条件下，界面原子混合σ~2随钛膜厚度的变化成一定的规律。另外，还就Ti/AL离子事混合进行了计算机Nonte Carto模拟计算，并与实验结果进行了比较和讨论

HIRFL剥离器后切束线物理设计

HIRFL is a tandem cyclotron complex for heavy ion. On the beam line between SFC and SSC, there is a stripper. Behind it, the distribution of charge states of beam is a Gauss distribution. The equilibrium charge state Q_0 is selected by 1BO2(a 50° dipole behind the stripper) and delivered to SSC. One of two new small beam line (named SLAS) after 1B02 will be builded in or der to split and deliver the unused ions of charge states (Q_0 ± n) to aspecific experimental area. Q_0 ± n ions are septumed and separated from initial(Q_0) ion beam by two septum magnets SM1, SM2. The charge state selected by SM1 will be Q_0 ± 1(6 ≤ Q_0 < 17), Q_0 ± 2(17 ≤ Q_0 < 33) and Q_0 ± 3 (Q_0 ≥ 33) forming a beam in one of the two possine new beam line with the stripping energy of (0.2 to 9.83 Mev/A), an emittance of 10π mm.mrad in the two transverse planes and an intensity ranging from 10~(11) pps for z ≤ 10 to some 10~5 pps for the heaviest element. Behind SM2, a few transport elements (three dipoles and seven qudrupoles) tra nsport Q_0 ± n beam to target positions T1, T2 (see fig. 1) and generate small beam spots (φ ≤ 4mm, φ ≤ 6mm). The optics design of the beam line has been done based on SLAC-75 (a first and second - order matrix theory). beam optics calculation has been worked out with the TRANSPORT program. The design is a very economical thinking, because without building a new accelerator we can obtain a lower energy heavy ion beam to provide for a lot of atomic and solid state physical experiments

~170Ta核高自旋态的实验研究

本论文首先介绍了原子核高自旋态的历史、发展和现状，然后介绍了研究原子核高自旋态的理论方法和实验技术——在束γ谱学。最后给出我们所做的在束γ实验16O+159Tb，分析和讨论了170Ta的高自旋态及其特征。 利用在束γ谱学方法，通过16O+159Tb重离子融合蒸发反应，在束流能量105MeV下，研究了170Ta的高自旋态。观察到170Ta的三个转动带，其中新发现了一个由π1/2-[541]准质子和ν5/2-[523]准中子耦合而成的非扭曲型（nondistorted band）转动带，这是在此稀土区首次发现该种耦合模式，和一个不优先的转动系列，从而大大修正了原170Ta的高自旋能级纲图。在推转壳模型（CSM）的框架内，对170Ta的转动带结构进行了讨论。 通过延迟符合测量法对所观测到的同质异能态进行了寿命测量。测量并确定了169Ta的9/2-[514]带9/2-能级的半衰期为T1/2=28±5ns。169Ta的1/2-[541]带5/2-能级的半衰期为T1/2=17±5ns。

稠油高效降解菌的降解特性及其应用

以稠油为唯一碳源,对细菌B0501、B0505和B0510的降解特性进行了分析,结果表明3株菌对稠油的不同组分具有不同程度的降解能力,其中B0505对烷烃、B0510对芳香烃以及B0501对胶质和沥青质的去除率较高,分别为42.26%、35.30%和40.76%;混合菌协同作用强化了稠油组分的降解,3株菌株组合对烷烃、芳香烃以及胶质沥青质的降解率分别达到44.23%、38.56%和62.12%;微生物对稠油降解过程符合一级动力学方程,其中3株菌株组合对稠油降解的速率最快,半衰期(t1/2)为5.36 d。将微生物应用于稠油废水处理实践,结果表明外源微生物的投加强化了废水中COD的去除率;GC-MS图谱及降解前后有机成分分析进一步佐证了微生物对稠油废水中有机成分的降解能力。

黄土丘陵区典型植物群落根系垂直分布与环境因子的关系

深入研究植被恢复过程中根系与环境因子的响应规律,对于当前西部地区的生态环境建设中有关林草措施的配置问题具有重要理论意义和实践价值。采用对应分析(CA)和典范对应分析(CCA)方法研究黄土丘陵区4种典型植物群落的根系垂直分布特征及其与环境因子的关系。结果表明,所选群落的根系生物量随土层深度增加而明显减小,0~40 cm土层根系生物量超过总根量的85%。借助CA分析将根系的垂直分布特征分为T1、T2和T3,其中大多数群落属于T1型,即表层根量聚积型,0~20 cm土层根量远高于其他层次;T2和T3型为深根与浅根型根系的组合类型,层次变化相对缓和。群落根系的垂直分布及变化受环境因子的综合影响,T1型分布在硝态氮含量较高且有机质和全氮含量较低的地段;T2和T3型的有机质和全氮含量较高,硝态氮含量较低;土壤水分含量、密度、硝态氮是影响退耕地典型植物群落根系垂直分布特征的主要环境因子。

Observation of Slow Magnetic Relaxation in Discrete Dysprosium Cubane

A discrete dysprosium cubane has been prepared and structurally characterized Slow relaxation of magnetization in this complex is observed, which may stimulate further investigations into the dynamics of magnetization in lanthanide clusters with different topologies.

A HIGH-RESOLUTION SOLID-STATE NMR AND DSC STUDY OF MISCIBILITY AND CRYSTALLIZATION BEHAVIOR OF POLY(VINYL ALCOHOL)/POLY(N-VINYL-2-PYRROLIDONE) BLENDS

Blends of crystallizable poly(vinyl alcohol) (PVA) with poly(N-vinyl-2-pyrrolidone) (PVPy) were studied by C-13 cross-polarization/magic angle spinning (CP/MAS) n.m.r. and d.s.c. The C-13 CP/MAS spectra show that the blends were miscible on a molecular level over the whole composition range studied, and that the intramolecular hydrogen bonds of PVA were broken and intermolecular hydrogen bonds between PVA and PVPy formed when the two polymers were mixed. The results of a spin-lattice relaxation study indicate that blending of the two polymers reduced the average intermolecular distance and molecular motion of each component, even in the miscible amorphous phase, and that addition of PVPy into PVA has a definite effect on the crystallinity of PVA in the blends over the whole composition range, yet there is still detectable crystallinity even when the PVPy content is as high as 80 wt%. These results are consistent with those obtained from d.s.c. studies.

A HIGH-RESOLUTION SOLID-STATE NMR-STUDY OF THE MISCIBILITY, MORPHOLOGY, AND TOUGHENING MECHANISM OF POLYSTYRENE WITH POLY(2,6-DIMETHYL-1,4-PHENYLENE OXIDE) BLENDS

An extended Goldman-Shen pulse sequence was used to observe indirectly the proton spin diffusion in the blends of polystyrene (PS) with poly(2,6-dimethyl-1,4-phenylene oxides) (PPO). The results indicate that the average distance between PS and PPO is less than 5 angstrom in the intimately mixed phase, but there are heterogeneous domains on a 100-angstrom scale. The data of spin relaxation of carbons, T1(C), for homopolymers and their blends suggest that there is a strong pi-pi electron conjugation interaction between the aromatic rings of PS and those of PPO, while the aromatic rings of PPO drive the aromatic rings of PS to move cooperatively. It is the cooperative motion that markedly improves the impact strength of PS.

碳-13核磁共振定量测定萄葡糖及果糖的含量

本文利用~(13)C-NMR方法测量由葡萄糖通过葡萄糖异构酶的作用,在不同的条件下,在转化为果糖的过程中葡萄糖和果糖的相对含量。同时~(13)C-NMR技术也是直接测定各种构型糖含量的有效方法。实验结果表明,Gd-DPTA弛予试剂能够使自旋-晶格弛豫时间(T1)缩短。同时对NOE效应的消除也作了描述。本法测定的相对误差低于±0.5％。

The complete mitochondrial genomes of two common shrimps (Litopenaeus vannamei and Fenneropenaeus chinensis) and their phylogenomic considerations

Complete mitochondrial genomes have proven extremely valuable in helping to understand the evolutionary relationships among metazoans. However, uneven taxon sampling may lead to unclear or even erroneous phylogenetic topologies. The decapod crustaceans are relatively well-sampled, but sampling is still uneven within this group. We have sequenced the mitochondrial genomes of two shrimps Litopenaeus vannamei and Fenneropenaeus chinensis. As seen in other metazoans, the genomes contain a standard set of 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes and an AT-rich non-coding region. The gene arrangements are consistent with the pancrustacean ground pattern. Both the pattern of gene rearrangements and phylogenomic analyses using concatenated nucleic acid and amino acid sequences of the 13 mitochondrial protein-coding genes strengthened the support that Caridea and Palinura are primitive members of Pleocyemata. These sequences, in combination with two previously published penaeid mitochondrial genomes, suggest that genera within the family Penaeidae have the following relationship: (((Penaeits + Fenneropenaett.) + Litopeiiaelts) + Marsupenaeus). The analyses of nucleic acid and amino acid sequences of the mitochondrial genomes also strongly support the monophyly of Penaeidae, Brachyura and Pleocyemata. In addition, the analyses of the average Ka/Ks in the 13 mitochondrial protein-coding genes of penaeid shrimps indicated a strong purifying selection within this group.

两种红树林植物黄槿和长梗肖槿化学成分研究

由于红树林植物的重要药用价值及其特殊的生长环境，越来越多的学者关注于红树林植物的活性成分及其作用机理的研究。本论文对两种药用红树林植物黄槿（Hibiscus tiliaceus L.）和长梗肖槿（Thespesia populneoides (Roxb.) Kostel）的化学成分进行了系统研究。对从其中分离得到的部分化合物进行了初步的抗菌活性筛选。 黄槿和长梗肖槿均采自海南岛，干燥粉碎的样品用90％的乙醇水以及1：1氯仿-甲醇混合溶液室温浸泡提取得总浸膏，将总浸膏悬浮于水中，分别用石油醚和乙酸乙酯萃取，获得石油醚相和乙酸乙酯相萃取物。 采用常规的硅胶柱层析、制备薄层层析、凝胶Sephadex LH-20柱层析、反相硅胶柱层析、以及重结晶等手段，从黄槿和长梗肖槿的乙酸乙酯相中共分离得到43个化合物。利用各种现代波谱技术（IR、UV、MS、HR-MS、1D-NMR、2D-NMR等）确定了38个化合物的结构。其中，从黄槿的乙酸乙酯相中分离得到22个化合物，鉴定了其中19个化合物的结构，包括3个新的三萜类化合物(H1*-H3*)以及15个首次从该种中报道的化合物。从长梗肖槿的乙酸乙酯相中分离得到21个化合物，鉴定了其中19个化合物的结构，这些化合物皆为首次从该种中报道，其中1个为新的倍半萜类化合物T1*。本文为首次报道长梗肖槿的化学成分。 对分离得到的部分样品进行了抗菌活性测试，仅T1*表现微弱的抗金黄色葡萄球菌活性，抑菌圈直径为8mm（阳性对照氯霉素的抑菌圈直径为20mm），其余各样品在测试浓度下对测试菌株均未表现出活性。

山东沿海养殖栉孔扇贝大批死亡原因的初步研究

栉孔扇贝（Chlamysfarreri）是中国北方三种主要养殖扇贝中唯一的土著扇贝科种类,在中国主要分布在黄海北部和渤海海峡,过去一直是中国干贝的产出贝.该研究主要从养殖密度、病原、遗传三方面入手,研究和探讨造成养殖栉孔扇贝大批死亡的原因.2000年5月～9月,按高、中、低三种密度在山东胶南、蓬莱、烟台筏式挂养栉孔扇贝苗,分别在大规模死亡前、死亡高峰时和死亡后统计死亡率分别样本.对死亡期间的瞬时生长率研究发现,随着时间的推移,栉孔扇贝壳高增长率趋于减小,而扇贝全湿重的增长率却在T0-T1时间段呈现一个高峰,说明栉孔扇贝在大规模死亡前经历过一个块速增重的阶段.采用7条随机引物,对大连野生野体、韩国野生群体、中国日本杂交群体在胶南、蓬莱放养采样得到的养殖群体,总共5群体140个个体的全基因组DNA进行RAPD扩增,共扩增出37条谱带,其中30条具有多态性.

Genetic diversity and historical population structure of Schizopygopsis pylzovi (Teleostei : Cyprinidae) in the Qinghai-Tibetan Plateau

1. Complete sequences of 1140 base pair of the cytochrome b gene from 133 specimens were obtained from nine localities including the inflow drainage system, isolated lakes and outflow drainage system in Qinghai-Tibetan Plateau to assess genetic diversity and to infer population histories of the freshwater fish Schizopygopsis pylzovi.2. Nucleotide diversities (pi) were moderate (0.0024-0.0045) in populations from the outflow drainage system and Tuosuo Lake, but low (0.0018-0.0021) in populations from Qiadam Basin. It is probable that the low intra-population variability is related with the paleoenvironmental fluctuation in Qiadam Basin, suggesting that the populations from Qiadam Basin have experienced severe bottleneck events in history.3. Phylogenetic tree topologies indicate that the individuals from different populations did not form reciprocal monophyly, but the populations from the adjacent drainages cluster geographically. Most population pairwise F-ST tests were significant, with non-significant pairwise tests between Tuosu Lake and Tuosuo Lake in the north-west of the Qinghai-Tibetan Plateau. Analysis of molecular variance (AMOVA) indicates that the significant genetic variation was explained at the levels of catchments within and among, not among specific boundaries or inflow and outflow drainage systems.4. The nested clade phylogeographical analysis indicates that historical processes are very important in the observed geographical structuring of S. pylzovi, and the contemporary population structure and differentiation of S. pylzovi may be consistent with the historical tectonic events occurred in the course of uplifts of the Qinghai-Tibetan Plateau. Fluctuations of the ecogeographical environment and major hydrographic formation might have promoted contiguous range expansion of freshwater fish populations, whereas the geological barriers among drainages have resulted in the fragmentation of population and restricted the gene flow among populations.5. The significantly large negative F-s-value (-24.91, P < 0.01) of Fu's F-s-test and the unimodal mismatch distribution indicate that the species S. pylzovi underwent a sudden population expansion after the historical tectonic event of the Gonghe Movement.6. The results of this study indicate that each population from the Qinghai-Tibetan Plateau should be managed and conserved separately and that efforts should be directed towards preserving the genetic integrity of each group.