201 resultados para 15-146


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By using phi-mapping method, we discuss the topological structure of the self-duality solution in Jackiw-Pi model in terms of gauge potential decomposition. We set up relationship between Chern-Simons vortex solution and topological number, which is determined by Hopf index and Brouwer degree. We also give the quantization of flux in this case. Then, we study the angular momentum of the vortex, which can be expressed in terms of the flux.

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The relative partial cross sections for C-13(6+)-Ar collisions at 4.15-11.08 keV/u incident energy are measured. The cross-section ratios sigma(2E)/sigma(SC), sigma(3E)/sigma(SC), sigma(4E)/sigma(SC) and sigma(5E)/sigma(SC) are approximately the constants of 0.51 +/- 0.05, 0.20 +/- 0.03, 0.06 +/- 0.03 and 0.02 +/- 0.01 in this region. The significance of the multi-electron process in highly charged ions (HCIs) with argon collisions is demonstrated (sigma(ME)/sigma(SC) as high as 0.79 +/- 0.06). In multi-electron processes, it is shown that transfer ionization is dominant while pure electron capture is weak and negligible. For all reaction channels, the cross-sections are independent of the incident energy in the present energy region, which is in agreement with the static characteristic of classic models, i.e. the molecular Coulomb over-the-barrier model (MCBM), the extended classical over-the-barrier (ECBM) and the semiempirical scaling laws (SL). The result is compared with these classical models and with our previous work of C-13(6+)-Ne collisions

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The cross-section ratios of double-, triple-, quadruple-, and the total multi-electron processes to the single electron capture process sigma(DE)/sigma(SC), sigma(TE)/sigma(SC), sigma(QE)/sigma(SC) and sigma(ME)/sigma(SC)) as well as the relative ratios among reaction channels in double-electron active, triple-electron active and quadruple- electron active are measured in C-13(6+) -Ne collision in the energy region of 4.15-11.08 keV/u by employing position-sensitive and time-of-flight coincident techniques. It is determined that the cross-section ratios sigma(DE)/sigma(SC), sigma(TE)/sigma(SC), sigma(QE)/sigma(SC) and sigma(ME)/sigma(SC) are approximately the constants of 0.20 +/- 0.03, 0.16 +/- 0.04, 0.06 +/- 0.02 and 0.42 +/- 0.05. These values are obviously smaller than the predictions of the molecular Coulomb over-the-barrier model (MCBM) [J. Phys. B 23 (1990) 4293], the extended classical over-the-barrier model (ECBM) [J. Phys. B 19 (1986) 2925] and the semiempirical scaling laws (SL) [Phys. Rev. A 54 (1996) 4127]. However, the relative ratios among partial processes of DE, TE and QE are found to depend on collision energy, which suggests that the collision dynamics depends on the collision velocity. The limitation of velocity-independent character of ECBM, MCBM and SL is undoubtedly shown.

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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.

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本文首先回顾了重离子物理学的发展简史,并介绍了当前的一些关于重离子反应的理论方法,同时对于现在核物理的研究热点,热核的特性进行了概括性的叙述.由于裂变是作者工作的重点,因此在文章中,对裂变反应的理论也进行了介绍.为了能够清楚全面的说明我们的工作,本文对于实验装置和探测器也给出了详细的描述.最后,文章对25 MeVu Ar+Bi反应中的裂变进行了讨论.在这些讨论中,我们分析了反应中与裂变相关的数据,得到了碎片的质量,动能分布。同时运用与碎片相关联的4He粒子能谱提取了核温度和裂前裂后的4He粒子多重性,并利用这一数据计算了不同初始激发能下的裂点激发能和裂变时标.

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由地衣芽孢杆菌(Bacilluslicheniformis)H19和2—酮基—L—古龙酸产生菌S19的原生质体融合,得到了既能独立生长传代,又能产生2—酮基—L—古龙酸的15号融合子。其菌落和菌体形态类似于H19亲本,其生理生化特性也大多酷似H19亲本而不同于S19亲本。但其产生2—酮基—L—古龙酸的特性、乙醇氧化反应、石蕊牛奶产酸以及精氨酸双水解酶阴性等特点又酷似S19亲本而不同于H19亲本。其氧化酶反应、初始生长pH范围、苯丙氨酸和色氨酸脱氨酶反应则不同于双亲本。其菌体的氨基酸组份及含量也与双亲有一定差异。