研究了乙烯/醋酸乙烯酯(EVA)二元共聚物和乙烯/醋酸乙烯酯/—氧化碳(E-VACO)三元共聚物的热分解机理和动力学。用 Doyle—Ozawa 积分法处理实验数据,给出分解活化能。结果表明,共单体一氧化碳作为第三组分引入 EVA 共聚物分子链上可以...研究了乙烯/醋酸乙烯酯(EVA)二元共聚物和乙烯/醋酸乙烯酯/—氧化碳(E-VACO)三元共聚物的热分解机理和动力学。用 Doyle—Ozawa 积分法处理实验数据,给出分解活化能。结果表明,共单体一氧化碳作为第三组分引入 EVA 共聚物分子链上可以提高其热稳定性。展开更多
The non-Hermitian PT-symmetric system can live in either unbroken or broken PT-symmetric phase. The separation point of the unbroken and broken PT-symmetric phases is called the PT-phase-transition point.Conventionall...The non-Hermitian PT-symmetric system can live in either unbroken or broken PT-symmetric phase. The separation point of the unbroken and broken PT-symmetric phases is called the PT-phase-transition point.Conventionally, given an arbitrary non-Hermitian PT-symmetric Hamiltonian, one has to solve the corresponding Schrodinger equation explicitly in order to determine which phase it is actually in. Here, we propose to use artificial neural network(ANN) to determine the PT-phase-transition points for non-Hermitian PT-symmetric systems with short-range potentials. The numerical results given by ANN agree well with the literature, which shows the reliability of our new method.展开更多
β-decay half-life is a key quantity for nuclear structure and nucleosynthesis studies.There exist large uncertainties in the contributions of allowed and forbidden transitions to the totalβ-decay life,which limits t...β-decay half-life is a key quantity for nuclear structure and nucleosynthesis studies.There exist large uncertainties in the contributions of allowed and forbidden transitions to the totalβ-decay life,which limits the resolution of the predictedβ-decay half-life.We systematically study the contribution of the first forbidden(FF)transitions to theβ--decay half-life,and quantify it with a formula based on simple physics considerations.We also propose a new formula for calculation of theβ--decay half-life that includes the FF contribution.It is shown that the inclusion of the contribution of FF transitions significantly improves the precision of calculations of theβ--decay half-life.By fitting of the RQRPA results for neutron-rich Z=47,57 isotopes and N=80,94 isotones,the formula for the contribution of the FF transitions gives similar results as the RQRPA calculations.However,because of limited experimental data for the branching ratios of unstable nuclei,the fit parameters are not fully constrained.Therefore,the proposed formula for theβ--decay half-life is more suitable for calculations of half-lives than of the FF contributions.The formula could be used to predict theβ?-decay half-life in nuclear structure studies as well as nucleosynthesis calculations in stars.展开更多
基金Supported by the National Natural Science Foundation of China (Grant Nos.11535004,11975167,11761161001,11375086,11565010,11881240623 and 11961141003)the National Key R&D Program of China (Grant Nos.2018YFA0404403 and 2016YFE0129300)+1 种基金the Science and Technology Development Fund of Macao (Grant No.008/2017/AFJ)the Fundamental Research Funds for the Central Universities (Grant Nos.22120210138 and 22120200101)。
文摘The non-Hermitian PT-symmetric system can live in either unbroken or broken PT-symmetric phase. The separation point of the unbroken and broken PT-symmetric phases is called the PT-phase-transition point.Conventionally, given an arbitrary non-Hermitian PT-symmetric Hamiltonian, one has to solve the corresponding Schrodinger equation explicitly in order to determine which phase it is actually in. Here, we propose to use artificial neural network(ANN) to determine the PT-phase-transition points for non-Hermitian PT-symmetric systems with short-range potentials. The numerical results given by ANN agree well with the literature, which shows the reliability of our new method.
基金Supported by National Natural Science Foundation of China(11565010,U1731218,11761161001)the Science and Technology Fund of Guizhou Province((2015)4015,(2016)-4008))the Science and Technology Development Fund(FDCT) of Macao(020/2014/A1,008/2017/AFJ,119/2017/A3)
文摘β-decay half-life is a key quantity for nuclear structure and nucleosynthesis studies.There exist large uncertainties in the contributions of allowed and forbidden transitions to the totalβ-decay life,which limits the resolution of the predictedβ-decay half-life.We systematically study the contribution of the first forbidden(FF)transitions to theβ--decay half-life,and quantify it with a formula based on simple physics considerations.We also propose a new formula for calculation of theβ--decay half-life that includes the FF contribution.It is shown that the inclusion of the contribution of FF transitions significantly improves the precision of calculations of theβ--decay half-life.By fitting of the RQRPA results for neutron-rich Z=47,57 isotopes and N=80,94 isotones,the formula for the contribution of the FF transitions gives similar results as the RQRPA calculations.However,because of limited experimental data for the branching ratios of unstable nuclei,the fit parameters are not fully constrained.Therefore,the proposed formula for theβ--decay half-life is more suitable for calculations of half-lives than of the FF contributions.The formula could be used to predict theβ?-decay half-life in nuclear structure studies as well as nucleosynthesis calculations in stars.
