Study of multi-quasiparticle excited states in Ce-139

High-spin states in Ce-139 have been populated using the Te-130(C-12, 3n) reaction at beam energy of 50MeV. The level scheme of Ce-139 has been revised and extended greatly up to E=5765.0keV. The level structure of Ce-139 shows typical characteristics of spherical nucleus, and the high-spin states were formed by the excitations of valence nucleons. Energies of the yrast and near yrast high-spin states in Ce-139 have been calculated by the empirical shell model, and the multi-quasiparticle nature of high-spin excited states has been discussed.

Measurement of the inelastic branch of the stellar O-14(alpha,p)F-17 reaction occurring in the explosive burning in Novae and X-ray busters

The inelastic component of the key astrophysical resonance (1(-), E-x=6.15 MeV) in the O-14(alpha,p)F-17 reaction has been studied by using the resonant scattering of F-17+p. The experiment was done at REX-ISOLDE CERN with the Miniball setup. The thick target method in inverse kinematics was utilized in the present experiment where a 44.2 MeV F-17 beam bombarded a similar to 40 mu m thick (CH2)(n) target. The inelastic scattering protons in coincidence with the de-excited 495 keV gamma rays have been clearly seen and they are from the inelastic branch to the first excited state in F-17 following decay of the 1(-) resonance in Ne-18. Some preliminary results are reported.

Dipole bands in nucleus Pm-139

High-spin states in nucleus Pm-139 have been studied using the reaction Cd-116(Al-27, 4n)Pm-139. Two dipole cascades have been found. Spin and parity assignments were based on the Directional Correlation of Oriented Nuclei (DCO) ratios and systematic behavior in neighboring odd-proton nuclei. The level structures of Pm-139 are compared with those of the N = 78 isotone Eu-141 in which two dipole bands have been confirmed as magnetic rotational bands. The close similarity between them suggests that the dipole bands in Pm-139 may be magnetic rotational bands.

~(139)Pm高自旋态的实验研究；Experimental observation of high spin states in ~(139)Pm nucleus

通过重离子核反应116Cd(27Al,4n)与在束γ谱的实验技术,对A=130~140核区的奇A核139Pm的高自旋态进行了研究.根据γ-γ符合关系、γ射线的相对强度和各向异性度的测量结果,扩展并更新了139Pm的能级纲图.实验观测到基于πh11/2和πg7/2-[πh11/2]2(或者πd5/2-[πh11/2]2)组态的转动带,利用已有的理论计算结果对这些转动带进行了解释.同时还观测到三个具有很强M1跃迁、旋称劈裂很小的-I=1的带.通过简单分析和系统学比较,指认了它们的组态,发现它们具备磁转动带的特性,很可能是磁转动带.

球形核139Ce和过渡区核189Pt高自旋态能级结构研究

本论文主要包括以下两部分： 利用能量为50 MeV的 12 C 束流，通过反应 130 Te( 12 C,3n)产生了 139 Ce 的高自旋态。 基于标准在束核谱学实验方法，利用由14套BGO（AC）HPGe 探测器组成的探测器阵 列，进行了X- γ -t和 γ - γ -t符合测量，更新并扩展了 139 Ce 的高自旋能级纲图。139 Ce 的能级结构具有球形原子核的典型特征，其高自旋态是由单粒子激发形成的。本文利用 经验壳模型计算了 139 Ce 的多准粒子激发态能量，研究了其高自旋激发态的多准粒子特 性。 利用能量为88和95 MeV的 18 O 束流，通过重离子熔合蒸发反应 176 Yb( 18 O,5n)，布 居了 189 Pt 的高自旋激发态。实验采用 GEMINI γ射线探测器阵列，进行了X- γ -t 和 γ - γ -t 符合测量。基于γ - γ符合关系、γ射线相对强度、强度平衡原理和交叉跃迁等 信息，建立了新的 189 Pt 高自旋态能级纲图。实验观测到基于 1 13/2 i υ − ， 5/23/2 () f p υ 和 2 13/25/23/2 () ifp υυ − 组态的转动带以及多准粒子激发能级。其中， 1 13/2 i υ − 带的优惠和非优惠旋 称分支分别被扩展到 49/2+ 和31/2+ 能级。本工作利用三轴粒子-转子模型分析了基于 1 13/2 i υ − ， 5/23/2 () f p υ 组态的转动带性质，分析了它们波函数的主要成分，并建议它们分别 具有三轴形变和长椭形变。实验上发现结构非常相近的两个能级序列，我们建议它们具 有 2 13/25/23/2 () ifp υυ − 组态。第一次利用粒子-转子模型计算了这个基于三准粒子组态的转动 带能级能量，很好地再现了实验结果，并建议此带具有扁椭形变。由于与这个组态相应 的 Nilsson 轨道量子数显示了赝自旋量子数特征，我们建议此三准粒子组态转动带为赝 自旋伙伴带。

94.5Mev ~(14)N+~(59)Co反应系统准弹及深度非弹研究

通过对94.5 Mev ~(14)N+~(59)Co反应数据的处理，得到了Li-Ne产物出射的wilczynski图、角分布、电荷分布，并对它们做了一些常规的分析工作。在Feldmeier模型框架下对该系统作了经典轨道动力学计算，给出了计算结果并对它们做了说明。本工作为轻系统低轰击能量下周边碰撞的系统性研究提供了一些参考数据

~(14)N+~(51)耗散碰撞研究

本文主要研究了~(14)N+~(51)V(E_n = 94.6 MeV, 86.83 MeV, 79.2 MeV)的耗散碰撞，是上述系统性研究工作的一个重要组成部分。对N＋~(51)V系统的DIC反应作了比较详细的研究，给出了类弹产物质心系维辛斯基图，不同出射道及不同TKEL下的角分布，以及不同TKEL不的电荷分布。从这些实验结果中提取全弛豫动能，相互作用时间，及电荷分布的一次矩，二次矩。讨论了~(14)N+~(51) 耗散碰撞随相互作用时间的推移的演化过程，定性分析了壳效应对N＋V反应中电荷漂移的影响。同时还指出N＋V反应中α集团效应的影响是不重要的，为~(16)O+~(27)Al 研究中提出的强α集团效应对其DIC过程有影响这一观点提供了旁证。最后提取了准弹截面，DIC截面，从而导出全熔合截面，讨论了DIC反应对轰击能的依赖关系

~(14)C-菲在营养液-火山石-小麦有控系统中的迁移和转化

利用放射性同位素示踪技术研究了１４Ｃ标记菲在有控系统中的迁移转化．结果表明，１４Ｃ菲在有控系统中降解较快，施入药品２４ｄ后仅有０．３２％的１４Ｃ－菲存留在植物、营养液和火山石中．植物吸收的１４Ｃ放射性大部分被结合到植物组织中，其它１４Ｃ主要以菲的极性代谢物形态存在．

Vc二步发酵新组合菌系B_(15-14)的筛选及其条件优化

筛选出了一组Vc二步发酵的新组合菌系(命名为B15-14),研究了环境因子对新菌系产酸的影响。结果显示:新组合菌系的最适底糖浓度为7%;温度为29~33℃,31℃为最适;适当增加通气量(20~30 mL装液量,250 mL三角瓶)有利于产酸;起始pH值范围为6.0~7.5;以B t菌做伴生菌时,发酵40 h就已达到终点,明显缩短了发酵时间。

油松水源保护林人工诱导更新与定向恢复机理

以油松水源保护林为对象,进行人工诱导更新与定向恢复机理研究。结果表明,在郁闭林分内油松更新苗密度平均为5 375株.hm-2,更新苗年龄为1~2年,而在人工Gap“效应岛”样地内,更新苗密度平均为17 062.5株.hm-2,其中1~2年、3~4年、5~6年生更新苗分别占73.44%,13.97%和12.59%;生长季光照强度在0、1.5和2.0 m三个不同高度梯度上,在Gap内部的平均值分别为289.0×100、542.0×100和589.0×100 lux,在对照林分内分别为139.0×100、146.0×100和246.0×100lux;从夏季观测到的空气温度平均值日变化分析,在白天Gap内的温度高于郁闭林分内部,温差可差2~3℃,在夜间Gap内的温度低于郁闭林分内,温差可差0.5~1℃;在白天6:00~11:00,人工Gap“效应岛”内空气湿度明显低于郁闭林分内,在其它时间段大致相当;对于同一层次土壤而言,Gap内的土壤温度明显高于郁闭林分内且变化幅度大,在0、10和20 cm三个梯度上Gap与郁闭林分相比土壤温度最大差值分别可达10、5和2℃;0~10、10~20和20~30 cm三个层次平均土壤含水量在Gap内分别为16.9%1、5.1%和12.3%,在郁闭林分内分别为14.6%、12.5%和9.9%。总体上比较二者的光照强度、空气温度、空气湿度、土壤温度、土壤水分等有显著差异,因此人工Gap“效应岛”的创建是诱导其内部微环境因子变化的基础,也是油松水源保护林定向恢复更新的机理之所在。

First principles investigation on the structural, mechanical and electronic properties of OsC2

The structural, mechanical and electronic properties Of OsC2 were investigated by use of the density functional theory. Seven structures were considered, i.e., orthorhombic Cmca (No. 12, OsSi2), Pmmn (No. 59, 002) and Pnnm (No. 58, OsN2); tetragonal P4(2)/mnm (No. 136, OsO2) and 14/mmm (No. 139, CaC2); cubic Fm-3m (No. 225, CaF2) and Pa-3 (No. 205, PtN2). The results indicate that Cmca in OsSi2 type structure is energetically the most stable phase among the considered structures. It is also stable mechanically. OsC2 in Pmmn phase has the largest bulk modulus 319 GPa and shear modulus 194 GPa. The elastic anisotropy is discussed. (C) 2009 Elsevier B.V. All rights reserved.

Sr_4Al_(14)O_(25)∶RE~(3+)(RE=Eu,Ce,Tb)中稀土离子的发光性质

采用高温固相反应合成了Sr4Al14O25∶RE3+(RE=Eu,Ce,Tb)样品,研究了其中Eu3+,Ce3+和Tb3+的光谱性质,以及Ce3+与Tb3+共掺时的能量传递现象;发现Eu3+,Ce3+和Tb3+占有两个格位,与Eu2+在此基质中的情况相似;在Tb3+的发射光谱中同时观察到了来自5D3与5D4的发射,表明两能级间无辐射跃迁过程不显著;Ce3+对Tb3+有敏化作用。

Morphology and structure of nylon-2,14 single crystals from dilute solution

A perfect single crystal of nylon-2,14 was prepared from 0.02% (w/v) 1,4-butanediol solution by a "self-seeding" technique and isothermal crystallization at 120 and 145 degreesC. The morphology and structure features were examined by transmission electron microscopy with both image and diffraction modes, atomic force microscopy, and wide-angle X-ray diffraction (WAXD). The nylon-2,14 single crystal grown from 1,4-butanediol at 145 degreesC inhabited a lathlike shape with a lamellar thickness of about 9 nm. Electron diffraction and WAXD data indicated that nylon-2,14 crystallized in a triclinic system with lattice dimensions a = 0.49 nm, b = 0.51 nm, c = 2.23 nm, alpha = 60.4degrees, beta = 77degrees, and gamma = 59degrees. The crystal structure is different from that of nylon-6,6 but similar to that of other members of nylon-2Y.