Rotation alignment in neutron-rich Cr isotopes: A probe of deformed single-particle levels across N=40

Recent experiments have reached the neutron-rich Cr isotope with N = 40 and confirmed enhanced collectivity near this subshell. The current data focus on low-spin spectroscopy only, with little information on the states where high-j particles align their spins with the system rotation. By applying the projected shell model, we show that rotation alignment occurs in neutron-rich even-even Cr nuclei as early as spin 8 (h) over bar h and, owing to shell filling, the aligning particles differ in different isotopes. It is suggested that observation of irregularities in moments of inertia is a direct probe of the deformed single-particle scheme in this exotic mass region.

SUPER-FRS/CR超导磁体力学性能分析

中国签订了为德国FAIR国际大科学工程加工SUPER-FRS/CR超导二极磁铁样机的合作备忘录。该超导二极磁铁属于常温铁芯、低温线圈的超导磁铁，该磁铁的磁场强度0.15～1.6T，偏转角度15°，偏转半径8125mm，磁场精度要求±1×10-4，磁铁总重量约50吨。磁铁铁芯采用0.5mm的硅钢片叠压成型，由中科院近代物理研究（IMP）所计算、设计制造，线圈采用4.2K液氦浸泡式超导线圈，由合肥等离子体所设计制造（IPP）。 超导磁体的力学性能分析一直是超导磁体的基础问题。本文利用有限元分析方法，借助有限分析工具ANSYS、ADINA、OPERA等，分析了超导磁体的电磁场，着重模拟计算了SUPER-FRS/CR超导二极磁铁的电磁力作用；模拟了降温过程，计算了杜瓦、线圈热应力的作用；并对SUPER-FRS/CR超导线圈进行地震载荷作用的模拟。对以上不同的受力作用所遵循的不同的机械设计准则，进行不同的分析，最后计算结果证明设计的结构是安全、可靠的。由于超导线圈的结构复杂，导致在线圈拐角的地方应力有些集中，但是并不影响结构的可靠性。 本文还介绍了超导实验线圈的一些工艺设计，例如超导线圈的绕制，低温材料的选择，电流引线的设计工艺，以及VPI工艺。并对实验磁体进行了一系列的低温性能测试，例如短样测试、降温实验等，获得了一些重要的低温实验参数。这些参数将为以后超导磁体的研制提供宝贵的依据

Cr/Al系统的离子束混合

用600kev的kr~+对Cr/Al薄膜系统进行了离子束混合研究。实验样品是在单晶硅上蒸镀约5000 A厚的铝膜，相继再上所需不同厚度的铬膜。Kr~+注入剂量范围在2.0 * 10~(15)～2.5 * 10~(16) kr~+/cm~2之间。用2.0 Mev的α粒子对注入前后的样品进行了背散射分析，发现铝谱的前沿和铬谱的后沿有明显的展宽，且随剂量的增大而加宽，Cr/Al界面原子混合扩展量的平方α~2注入剂量φ成线性关系；当注入剂量大于1.0 * 10~(16) kr~+/cm~2时，铝谱前沿和铬谱的后沿出现有明显的平坦，经理论拟合计算，发现有化合物形成，x射线衍射实验结果证明化合物形式为Al_(13)Cr_2。本文还得到了混合量Q与剂量的线性关系。最后，对混合机制进行了讨论

Adsorption and reaction of thiophene and H2S on Mo2C/Al2O3 catalyst studied by in situ FT-IR spectroscopy

The reactions of both thiophene and H2S onMo(2)C/Al2O3 catalyst have been studied by in situ FT-IR spectroscopy. CO adsorption was used to probe the surface sites of Mo2C/Al2O3 catalyst under the interaction and reaction of thiophene and H2S. When the fresh Mo2C/Al2O3 catalyst is treated with a thiophene/H-2 mixture above 473 K, hydrogenated species exhibiting IR bands in the regions 2800-3000 cm(-1) are produced on the surface, indicating that thiophene reacts with the fresh carbide catalyst at relatively low temperatures. IR spectra of adsorbed CO on fresh Mo2C/Al2O3 pretreated by thiophene/H-2 at different temperatures clearly reveal the gradual sulfidation of the carbide catalyst at temperatures higher than 473 K, while H2S/H-2 can sulfide the Mo2C/Al2O3 catalyst surface readily at room temperature (RT). The sulfidation of the carbide surface by the reaction with thiophene or H2S maybe the major cause of the deactivation of carbide catalysts in hydrotreating reactions. The surface of the sulfided carbide catalyst can be only partially regenerated by a recarburization using CH4/H-2 at 1033 K. When the catalyst is first oxidized and then recarburized, the carbide surface can be completely reproduced.