Nuclear Potential and Fusion Cross Sections for Synthesizing Super-Heavy Elements in Di-nuclear Systems

A double foMing method with simplified Skyrme-type nucleon nucleon interaction is used to calculate the nuclear interaction potential between two nuclei. The calculation is performed in tip-to-tip orientation of the two nuclei if they are deformed. Based on this method, the potential energy surfaces~ the fusion probabilities and the evaporation residue cross sections for some cold fusion reactions leading to super-heavy elements within di-nuclear system model are evaluated. It is indicated that after the improvement, the exponential decreasing systematics of the fusion probability with increasing charge number of projectile on the Pb based target become better and the evaporation residue cross sections are in better agreement with the experimental data.     

N-亚硝基化合物导致DNA股间交联的HPLC-ESI-MS/MS分析

N-亚硝基化合物(NNCs)是一种重要的环境致癌物,它们能够导致DNA股间交联从而诱发癌症.研究表明NNCs经过代谢活化或分解后,最终以乙撑的形式导致DNA互补碱基对成对负性原子之间的共价交联.     

珠状大孔缩聚树脂合成及脱色性能研究

以苯酚、甲醛、水扬酸、四乙烯五胺为单体,Na_2SO_4为致孔剂,采用悬浮聚合法制得了大孔珠状缩聚型弱碱离子交换树脂。研究了原料配比,致孔剂用量等对树脂性能的影响。     

In1-xGaxAsyP1-y/InP异质界面晶格失配对外延晶体质量的影响

用X-射线双晶衍射,双晶形貌术和光致发光方法综合研究了In1-xGaxAsyP1-y/InP异质界面晶格失配对LPE晶体质量的影响。实验表明,异质界面晶格失配是导致外延层中位错和缺陷增多,杂质凝聚和辐射复合深中心增多的重要因素。     

一种特殊设计约束面的有限元网格优化问题

网格设计质量的优劣是有限元分析的关键，对一些特殊的设计约束面，网格的优化设计是建模时需要首先研究解决的问题，本文对两种材料在几何尺寸差异很大情况下的有限元网格进行了优化设计并对其进行了讨论。     

二次谐波发射的时间截止或迟后特性研究

本文论述了在较宽脉冲或在人为引入预脉冲的激光与等离子体相互作用中的二次谐波发射的新特性,特别是在时间分辨特性上的截止或迟后发射的行为。研究表明,受激布里渊散射是导至低z靶所发射的二次谐波时间截止特性的主要原因;而经典逆轫致吸收则可能是决定高z靶的二次谐波发射的时间分辨特性的重要机制。     

用NH_4~+型阳离子交换树脂从等电点结晶母液中吸附谷氨酸Ⅱ.

本文研究了用NH_+型阳离子交换树脂在不同条件下从等电点结晶母液中吸附谷氨酸时该树脂的交换容量和一定条件下的交换速度。在相同pH、谷氨酸浓度与温度下测定的不同表观流速(u)和固定床交换区高度(hz)的关系为:hz=130u~(0.716)。一定液体流速下,固定床多级连续试验验证了交换区高度测定的结果。连续吸附的谷氨酸吸附率>95％。     

激光产生等离子体中不均匀性结构的研究

用可见光探针阴影成像方法研究了在激光产生等离子体中出现的不均匀性结构,特别是由于流体力学不稳定性而在薄膜靶后表面出现的小尺度喷流结构。     

鲨鱼肝铁蛋白亚基解离与组装机理的研究

小批量制备质谱纯鲨鱼肝铁蛋白(Liver Ferritin of Sphyrna zygaena,SZLF)。在弱酸介质(pH1.0)中,天然电泳结果显示,SZLF蛋白质亚基20 min后开始解离。选用透射电子显微镜跟踪SZLF亚基解离与重组装全过程和蛋白壳与铁核尺寸变化,发现SZLF在亚基酸解离过程中,随着pH值的降低,铁核和蛋白壳的尺寸呈现相同的变化趋势,这种变化趋势可能与铁核内层铁的释放和蛋白壳的解离与去折叠有关。SZLF蛋白壳的重组装过程则是一个快速过程,并且是由松散熔球态向紧密态转变的过程。SZLF由单类型亚基组成,而马脾铁蛋白(Horse Spleen Ferritin,HSF)由H和L两种亚基类型组成。在基质pH3.0条件和激光辅助下,混合HSF和SZLF仍然可释放各自的亚基且形成准亚基离子,供基质辅助激光解析电离飞行时间质谱分析,说明此时SZLF的亚基间相互作用强度减弱但并没有去折叠。TEM技术在铁蛋白解离和重组装过程中的应用,为进一步研究铁蛋白纳米包装的过程和机理提供新颖的、可行的和更加直观的研究手段。     

A new probe of neutron skin thickness

The correlation between neutron-to-proton yield ratio (R_np) and neutron skin thickness (δ_np) in neutron-rich projectile induced reactions is investigated within the framework of the Isospin-Dependent Quantum Molecular Dynamics (IQMD) model. The density distribution of the Droplet model is embedded in the initialization of the neutron and proton densities in the present IQMD model. By adjusting the diffuseness parameter of neutron density in the Droplet model for the projectile, the relationship between the neutron skin thickness and the corresponding R_np is obtained. The results show strong linear correlation between R_np and δ_np for neutron-rich Ca and Ni isotopes. It is suggested that R_np may be used as an experimental observable to extract δ_np for neutron-rich nuclei, which is very interesting in the study of the nuclear structure of exotic nuclei, the equation of state (EOS) of asymmetric nuclear matter and neutron-rich matter in astrophysics, etc.