代数$\Omega$-范畴的等价范畴

本文基于$\Omega$-范畴研究了(连续) $\mathcal{I}$-余万备$\Omega$-范畴的一些性质. 我们给出了双完备$\Omega$-范畴和逼近双模的概念并讨论了它们的性质, 证明了任何$\mathcal{I}$-余万备$\Omega$-范畴都是双完备$\Omega$-范畴. 得到了代数$\Omega$-范畴范畴等价于双完备$\Omega$-范畴.     

细胞色素P450酶催化的烷烃选择性羟化

碳氢键选择氧化是合成化学领域的重要课题,其中烷烃选择性羟化反应更是面临着化学选择性、区域选择性和立体选择性等多重挑战.细胞色素P450酶广泛分布于动植物和微生物体内,是公认的多功能生物氧化催化剂.P450酶对惰性C-H键的选择性氧化具有独特优势,在催化烷烃选择性羟化反应方面拥有巨大潜力.本综述简述了P450单加氧酶及其催化烷烃选择性羟化的反应机理,梳理了来自CYP153家族、CYP52家族和其他家族的天然P450酶催化各类烷烃底物的氧化反应和选择性,讨论了理性设计和定向进化策略在开发烷烃羟化P450突变酶过程中的经典案例,介绍了底物工程、诱饵分子、双功能小分子协同催化等几种化学活化P450酶的策略及其在烷烃羟化上的应用,探讨了P450酶在烷烃选择性羟化方面所面临的挑战和解决途径,并展望了其应用前景.     

Basic characteristics of nuclear landscape by improved Weizs?cker-Skyrmetype nuclear mass model

Atomic Mass Evaluation(AME2016) has replenished the latest nuclear binding energy data. Other physical observables, such as the separated energies, decay energies, and the pairing gaps, were evaluated based on the new mass table. An improved Weizs?cker-Skyrme-type(WS-type) nuclear mass model with only 13 parameters was presented, including the correction from two combinatorial radial basis functions(RBFs), where shell and pairing effects are simultaneously dealt with using a Strutinsky-like method. The RBFs code had 2267 updated experimental binding energies as inputs, and their correspondent root-mean square(rms) deviations dropped to 149 keV. For the training of other mass models by RBFs correction, rms deviations are clustered between 100 keV to 200 keV. Compared with other experimental quantities, the rms deviations calculated within the improved WS-type model falls between 100 keV and 250 keV. We extrapolate the binding energies to 12435 nuclei, which covers the ranges 8 ≤ Z ≤ 128 and 8 ≤ N ≤ 251 in the framework of the WS-type model with RBFs correction. Simultaneously, the ground state deformations β_(2,4,6) and all parts in the WS-type mass formula are presented in this paper. Finally, we tabulated all calculated characteristics within the improved formula and linked them to https://github.com/lukeronger/Nuclear Data-LZU: nuclear binding energies, one-nucleon and two-nucleon separation energies(S_(n,p,2n,2p)), and β-decay energies( Q_α and Q_(β-,β+,EC)), and the pairing gap ?_n and ?_p.     

合成Z=119, 120超重核的理论研究

合成Z=119,120超重核是当今各核物理实验室争相追逐的目标,理论预言可靠的弹靶组合、入射能等信息有助于超重核合成的实验设计和探测。本工作基于双核模型研究影响重离子核反应生成截面大小的反应机制,计算了$^{50}{\rm{Ti}}$+$^{249}{\rm{Bk}}$、$^{50}{\rm{Ti}}$+$^{249}{\rm{Cf}}$两个弹靶组合,预测$^{50}{\rm{Ti}}$+$^{249}{\rm{Bk}}$的生成截面为0.021 1 pb。考虑双核系统熔合与存活两个过程,重点关注$^{52-59}{\rm{Cr}}$+$^{243}{\rm{Am}}$、$^{54-62}{\rm{Mn}}$+$^{243}{\rm{Am}}$、$^{56-72}{\rm{Ni}}$+$^{238}{\rm{U}}$生成截面的同位素链依赖性,研究表明熔合几率随弹核质量数呈现强烈的依赖行为,直接影响蒸发剩余截面大小。