Search for signature inversion in the pi i(13/2) circle times upsilon i1(3/2) bands in Au-182,Au-184,Au-186

Search for low-spin signature inversion in the pi i(13/2) circle times nu i(13/2) bands in odd-odd Au-182,Au-184,Au-186 has been conducted through the standard in-beam gamma-spectroscopy techniques. The experiments for Au-182 and 186Au have been performed in the Japan Atomic Energy Agency (JAEA) via the Sm-152(Cl-35,5n)Au-182 and Yb-172(F-19,5n)Au-186 reactions, respectively. A study of Au-184 has been made using a multi-detector array GASP in LNL, Italy, via the Tb-159(Si-29,4n)Au-184 reaction. The pi i(13/2) circle times nu i(13/2) bands in these three nuclei have been identified and extended up to high-spin states. In particular, the inter-band connection between the pi i(13/2) nu i(13/2) band and the ground-state band in 184 Au has been established, leading to a firm spin-and-parity assignment for the pi i(13/2) circle times nu i(13/2) band. The low-spin signature inversion is found in the pi i(13/2) circle times nu i(13/2) bands in Au-182,Au-184,Au-186 according to our spin-assignment and the signature crossing observed at high-spin states.

Search for signature inversion in the pi i(13/2)circle times nu i(13/2) bands in Au-182,Au-184,Au-186

Search for low-spin signature inversion in the pi i(13/2) circle times nu i(13/2) bands in odd-odd Au-182,Au-184,Au-186 has been conducted through the standard in-beam gamma-spectroscopy techniques via the Sm-152(Cl-35,5n) Au-182, Yb-172(F-19,5n) (186)An, and Tb-159(Si-29,4n) (184)An reactions, respectively. The pi i(13/2) circle times nu i(13/2) bands in these three nuclei have been identified and extended up to high-spin states. In particular, the inter-band connection between the pi i(13/2) circle times nu i(13/2) band and the ground-state band in Au-184 has been established, leading to a firm spin-and-parity assignment for the pi i(13/2) circle times nu i(13/2) band. The low-spin signature inversion is found in the pi i(13/2) circle times nu i(13/2) bands according to our spin-assignment and-the signature crossing observed at high-spin states.

单次分子镀法制备部分La系及~(238)U靶的实验研究

采用单次分子镀方法研究了异丙醇-硝酸体系中电流密度、分子镀持续时间及两极间距离对镀层性能和电沉积效率的影响,确定了制备La,Sm,Eu,Gd,Tb靶及238U靶的最佳工艺条件。因制备的靶不同,电流密度一般介于2—8mA/cm2之间,两极间最优距离为3cm,分子镀1h,用分光光度法测定各靶的沉积效率均高于85%。利用扫描电子显微镜(SEM)对部分靶的表面形貌分析后发现靶面结构均匀致密。目前制得的Gd靶和Tb靶已用于中国科学院近代物理研究所加速器SFC低能核化学终端上,利用19F束流轰击,分别产生了Ta和W的短寿命同位素,从而成功完成了Db(Z=105)及Sg(Z=106)的模型试验。

Properties of the beta-delayed proton decay of Ho-146

The proton-rich isotope Ho-148 was produced via the fusion-evaporation reaction Mo-92 (Ni-58, 3p1n). The beta-delayed proton decay of Ho-146 was studied by proton-gamma coincidence measurements using a He-jet tape transport system. The gamma-transitions in Tb-145 following the proton emissions were observed, and the beta-delayed proton branching ratios to the final states in the grand-daughter nucleus Tb-145 were determined. According to the relative branching ratios, the ground-state spin of Ho-146 has been proposed and the possible configuration discussed.

The Compact Pulsed Hadron Source: A Design Perspective

During the past. decades, large-scale national neutron sources have been developed in Asia, Europe, and North America. Complementing such efforts, compact hadron beam complexes and neutron sources intended to serve primarily universities and industrial institutes have been proposed, and some have recently been established. Responding to the demand in China for pulsed neutron/proton-beam platforms that are dedicated to fundamental and applied research for users in multiple disciplines from materials characterization to hadron therapy and radiography to accelerator-driven sub-critical reactor systems (ADS) for nuclear waste transmutation, we have initiated the construction of a compact, yet expandable, accelerator complex-the Compact Pulsed Hadron Source (CPHS). It consists of an accelerator front-end (a high-intensity ion source, a 3-MeV radio-frequency quadrupole linac (RFQ), and a 13-MeV drift-tube linac (DTL)), a neutron target station (a beryllium target with solid methane and room-temperature water moderators/reflector), and experimental stations for neutron imaging/radiography, small-angle scattering, and proton irradiation. In the future, the CPHS may also serve as an injector to a ring for proton therapy and radiography or as the front end to an ADS test facility. In this paper, we describe the design of the CPHS technical systems and its intended operation.

New parameters of many-body potentials: studying the thermal and mechanical properties of noble metals

New parameters of nearest-neighbor EAM (1N-EAM), n-th neighbor EAM (NN-EAM), and the second-moment approximation to the tight-binding (TB-SMA) potentials are obtained by fitting experimental data at different temperatures. In comparison with the available many-body potentials, our results suggest that the 1N-EAM potential with the new parameters is the best description of atomic interactions in studying the thermal expansion of noble metals. For mechanical properties, it is suggested that the elastic constants should be calculated in the experimental zero-stress states for all three potentials. Furthermore, for NNEAM and TB-SMA potentials, the calculated results approach the experimental data as the range of the atomic interaction increases from the first-neighbor to the sixth-neighbor distance.

130Nd和140Tb的EC/ß+引衰变研究及其衰变纲图的建立

利用能量为220MeV左右的~(36)Ar重离子束轰击~(96)Ru和~(106)Cd浓缩同位素靶，通过Al降能片，使能量分布在161-176MeV之间，经过融合蒸发2p反应产生了缺中子同位素~(130)Nd, 经过融合蒸发pn反应生成~(140)Tb。藉助氦喷嘴带传输系统，用X-γ和γ-γ符合方法，分离鉴别了这两种核素，并进一步测定了它们的衰变性质。测定了~(130)Nd的半衰期为13 ± 3s，首次建议了它的EC/β~+衰变纲图，推测了其子核~(130)Pr的基态和低位能级的自旋宇称。修订了(140)Tb的原有极简单的EC/β~+衰变纲图，指认了~(140)Tb的基态自旋宇称为7~+。

35 A×MeV 40Ar + 159Tb/197Au 反应中高激发核性质与反应机制研究

中能重离子碰撞的反应机制及其形成的高激发核的性质研究是当前中能重离子核物理研究的重要领域。本文通过对35 MeV/u~(40)Ar+~(159)Tb/~(197)Au反应中出射的轻粒子、中等质量碎片(IMF)和复合核裂变碎片的符合测量，研究了中等质量碎片的发射机制、类靶核的形成机制及其裂变时标、复合核的温度与激发能以及两者之间的关系等。利用前角探测器组的测量对前角区出射的IMF的单举和关联数据进行了分析。由弹核碎裂理论中的Gozdhaber关系式拟合了类弹碎片的能谱，由此提取的弹核的动量分布约化宽度为σ_0 ≈ 100MevV/c。通过Gemini模拟与IMF-IMF关联数据的对比揭示出激发的类弹碎片的裂变是关联IMF的一个重要来源。由IMF与裂变碎片以及IMF与后角轻粒子的关联数据显示出，在前角区域，当IMF的能量低于10 MeV/u时，复合核的蒸发对较轻IMF有较大的贡献；当IMF能量在10-24 MeV/u的区域时，IMF能量与复合核平均速度以及激发能之间存在着很强的依赖关系，说明这些IMF主要来源与弹靶之间的耗散反应；当IMF的能量超过24 MeV/u后，IMF能量与复合核平均速度以及激发能之间没有关联或关联很弱，说明在弹核碎裂的同时，靶核也发生了碎裂，它们共同贡献出部分核子形成了"中速源"或"颈部"。通过对复合核裂变时出射的关联裂片以及后角轻带电粒子的测量，提取了复合核的激发能以及在不同激发能能下所对应的核温度。对于中心碰撞，Au靶形成了E~* = 4MeV/u、T_(init) = 7.1 MeV的热核，Tb靶形成了E~* = 4.7MeV/u、T_(init) = 7.7MeV的热核。对其量热曲线的研究显示出，在当前入射能下没有观测到原子核液气相变的特征。由类弹碎片（PLF)与类靶核两个裂片的关联数据，提取了类靶核裂变轴在反应平面内的转动角度，并由此计算出类靶核的、裂变时标。在对称裂变时，类靶核的寿命约5 * 10~(-20) s，在非对称裂变（η =0.6）时降为约1.7 * 10~(-21) S。同时我们认为类靶核的裂变存在两种机制，即动力学裂变和统计裂变，分别对应于裂变轴在反应平面内的非各相同性分别和各相同性分布。

热核的衰变行为研究

中能重离子碰撞（10－100 MeV/u）为研究热核性质提供了有力的工龄。为此我们利用HIRFL提供的46.7 MeV/u ~(12)C束轰击~(159)Tb/~(197)Au/~(209)Bi研究了线动量转移分析、出平面角分布和质量分布，实验结果的分析证实了非完全熔合核的裂变和蒸发。编写了一个Monte-Carlo统计衰变程序（SAGEE）并用于详细比较C＋Au、C＋Bi的实验数据，C＋Tb的质量分布由统计两体发射理论（GEMINI）得到了解释。理论与实验的符合说明：通常类熔合反应方式形成了高激发的复合核，其后以统计两体衰变而退激。实验也统计了与裂变符合的γ能谱、三裂变的相对角度和相对速度分布，没有观察到GDR，对称三裂不是唯一的三裂方式。本文分析了HIRFL上其他小组的实验结果。研究了46.7MeV/u ~(12)C＋~(58)Ni反应的复杂粒子发射，也研究了复杂粒子出射对用放射化学方法测量的24MeV/u ~(12)C＋~(64)Cu和42MeV/u ~(12)C＋~(115)In的质量产额分布的解释。GEMINI计算很好地符合了实验结果，这意味着非完全熔合反应形成的复合核的两体衰变仍是主要的发射过程。本文也简要讨论了多重碎裂过程。基于卡西尼亚卵形体裂变形状，计算了转动核的对称和非对称形变势能，用此模型得到了核的静态裂变位垒、鞍点能并与RLDM和RFRM作了比较。我们考虑了YPE核势对核表面的弥散作用以及弥散核表面对库仑能、转动惯量的影响完善了RCOM，我们的RFCOM比RLDM和RFRM都有明显的改进，可以用于重核裂变性质研究。发展了熔合－裂变过程的宏观模型，计算了形成复合核~(149)Tb、~(194)Hg的熔合过程及其相应的裂变过程。本工作对研究热核的形成及其衰变性无疑是很有用的

~(153)Er, ~(157)Yb(EC+#beta#~+)衰变纲图的首次建立

用蒸发中子反应产生~(157)Tb和~(153)Er，收集活性样品，作x, #gamma# 单谱及符合谱测量，对~(157)Yb和~(153)Er的(EC+#beta#~+)衰变进行了研究，给出了~(157)Yb及~(153)Er的衰变纲图，其中~(157)Yb的衰变纲图包括25条新#gamma#射线，分析~(157)Yb的衰变纲图，~(153)Er的衰变纲图包括15条#gamma#射线，并指定出~(153)Er半衰变期值，该值与文献给出值符合得很好。指定了~(153)Er的衰变纲图中能级状况

Solvothermal synthesis and characterization of Ln (Eu3+, Tb3+) doped hydroxyapatite

Luminescent Ln (Eu3+, Tb3+) doped hydroxyapatite (Eu:HAp, Tb:HAp) phosphors were successfully fabricated via the cetyltrimethylammonium bromide (CTAB)/n-octane/n-butanol/water microemulsion-mediated solvothermal process. The structure, morphology, and optical properties were systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectra (XPS), Fourier transform infrared spectroscopy (FT-IR), and photoluminescence (PL) spectra as well as the kinetic decays, respectively.

Manipulating charge-transfer character with electron-withdrawing main-group moieties for the color tuning of iridium electrophosphors

A new and synthetically versatile strategy has been developed for the phosphorescence color tuning of cyclometalated iridium phosphors by simple tailoring of the phenyl ring of ppy (Hppy=2-phenylpyridine) with various main-group moieties in [Ir(ppy-X)(2)(acac)] (X=B(Mes)(2), SiPh3, GePh3, NPh2, POPh2, OPh, SPh, SO2Ph). This can be achieved by shifting the charge-transfer character from the pyridyl groups in some traditional iridium ppy-type complexes to the electron-withdrawing main-group moieties and these assignments were supported by theoretical calculations.

Investigation of thermal expansion and compressibility of rare-earth orthovanadates using a dielectric chemical bond method

The chemical bond properties, lattice energies, linear expansion coefficients, and mechanical properties of ReVO4 (Re = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sc, Y) are investigated systematically by the dielectric chemical bond theory. The calculated results show that the covalencies of Re-O bonds are increasing slightly from La to Lu and that the covalencies of V-O bonds in crystals are decreasing slightly from La to Lu. The linear expansion coefficients decrease progressively from LaVO4 to LuVO4; on the contrary, the bulk moduli increase progressively. Our calculated results are in good agreement with some experimental values for linear expansion coefficients and bulk moduli.

Rhythmic Growth-Induced Ring-Banded Spherulites with Radial Periodic Variation of Thicknesses Grown from Poly(epsilon-caprolactone) Solution with Constant Concentration

Birefringent ring-banded spherulites with radial periodic variation of thicknesses were grown from poly(epsilon-caprolactone) (PCL) solutions under conditions for which the Solution concentration was held constant during the whole development of the morphology. The as-grown ring-banded spherulites were investigated by optical (OM) and atomic force (AFM) microscopies, by transmission electron microscopy (TEM) of samples sectioned parallel to the plane of film, and also by electron diffraction (ED) and grazing incidence X-ray diffraction (GIXD) techniques.

Effect of the nature of annealing solvent on the morphology of diblock copolymer blend thin films

The morphologies and structures for the thin film of blend systems consisting of two asymmetric polystyrene-block-polybutadiene (SB) diblock copolymers induced by annealing in the vapor of different solvents, namely, cyclohexane, benzene, and heptane, which have different selectivity or preferential affinity for a certain block, were investigated by tapping mode atomic force microscopy (AFM) and transmission electron microscopy (TEM). The results revealed that even a slight preferential affinity of good solvent for one block would strongly alter the morphology of the blend thin film.