测量正电子湮没辐射能量的一种方法

正电子湮没技术已广泛应用于各领域,但由于正电子源不易制备,没有反应堆或加速器的学校,要进行湮没辐射的测量确有困难。本文介绍用密封式14MeD—T中子发生器活化铜,通过~(63)Cu(D、2n)~(62)Cn反应制备正电子发射体,测量湮没辐射能量,其设备造价低,易于普及推广。     

非微扰方法研究B-→π0K-衰变过程

本文用 QCD因子化和光锥 QCD求和规则非微扰方法系统地计算了 B-→π 0K-衰变过程的强子矩阵元和分支比,其计算结果与实验相一致.     

The loop effects on the chargino decays ～χ±1→～χ0 1ff ′in the MSSM

The lighter chargino three body decays ～χ±1→～χ0 1ff ′ via the W^± boson and the charged Higgs boson H^± were studied in the R-parity conserved Minimal Supersymmetric Standard Model （MSSM）. We treat ～χ±1 decays as production and decay of W^± and H^± i.e.,～χ±1→～χ01W^±（H^±） → χ0 1ff ′. Both higgsino- like and wino-like ～χ±1 decays were well investigated. These decays are calculated at 1-loop level and the loop corrections are found to be less than three percent. The signal of the charged Higgs H^± production from ～χ±1 decays is discussed. It will offer important information about the chargino and neutralino sector, as well as the charged Higgs sector in the MSSM.     

原子核α衰变机制的量子理论解释

在解释原子核α衰变机制问题时,经典理论遇到难以克服的困难,量子理论的解释与实验结果相符.     

β衰变与同位旋对称性破缺

研究同位旋对称性破缺对于深入理解核力与核结构有着重要意义.我们在兰州重离子加速器国家实验室放射性束流线终端采用双面硅条与高纯锗组成强大的探测器阵列,精确测量sd壳质子滴线附近原子核β衰变性质,然后与其镜像核的衰变性质进行对比,系统性研究轻核区同位旋对称性破缺现象.     

放射源~(226)Ra和~(133)Ba的衰变γ能谱分析

采用p型同轴高纯锗探测器测量含~(226) Ra的荧光仪表盘与标准源~(133) Ba的衰变γ能谱,并分析特征γ射线的能量和强度.结果表明:~(226) Ra能谱中出现~(226) Ra的特征γ射线及大量~(226) Ra的衰变子核的特征γ射线;~(133)Ba谱中出现~(133)Ba特征射线及大量和峰,由计数率随距离变化关系及γ射线级联关系证明存在和峰.     

关于D波奇异介子的混合

在π2(1 670),η2(1 870)和η2(1 645)属于11 D2介子九重态的前提下,利用质量矩阵和非相对论组分夸克模型,对同位旋二重态K(1 D2)的质量给予讨论,二者的结果符合的很好.在此基础上,利用混合模型估算出D波介子中K(1 D2)与K(3 D2)间的混合角约为零度.而后,通过3 P0衰变模型计算K2(1 770)和K2(1 820)的部分衰变信息并与PDG提供的实验数据进行比较,建议目前实验上提供的衰变信息还不足以确定二者的混合程度.     

The nonleptonic two body B decays involving a light tensor meson in final states

The nonleptonic two body Bu,d,s,c decays involving a light tensor meson in final states are studied in the perturbative QCD approach based on kT factorization. The decay modes with a tensor meson emitted, are prohibited in naive factorization, since the emission diagram with a tensor meson produced from vacuum is vanished. While contributions from the so-called hard scattering emission diagrams and annihilation type diagrams are important and calculable in the perturbative QCD approach. The branching ratios of most decays are in the range of 10-4-10-8, which are bigger by 1 or 2 orders of magnitude than the predictions given by the naive factor- ization, but consistent with the predictions from the QCD factorization and the recent experimental measurements. We also give the predictions for the direct CP asymmetries, some of which are large enough for the future experiments to measure. We also find that, even with a small mixing angle, the mixing between f2 and f′2 can bring remarkable changes to both branching ratios and the direct CP asymmetries for some decays involving f2（′） mesons. For decays with a vector meson and a tensor meson in final states, we predict a large percentage of transverse polarization contributions due to the contributions of the orbital angular momentum of the tensor mesons.     

干法贮存系统乏燃料组件源项分析

为解决国内某些核电站乏燃料水池即将满容的问题,需要将乏燃料组件移出水池进行干法贮存.目前计划用于干法贮存的组件按照初始富集度的不同可分为六类,需要得到具有包络性的组件初始富集度与燃耗深度的运行史组合,并为干法贮存系统分析提供中子能谱、光子能谱、衰变热以及裂变气体的摩尔质量等包络性的源项.文章主要采用燃耗计算程序,针对A...     

城市老旧小区老年人户外活动休息点分布量化研究

为解决城市老旧小区内老年人户外活动休息点建设中易受主观因素影响,且未能真实反映老年人群体需求,无法快速评估和预测休息点的分布问题,通过跟踪记录与问卷访谈的方法,研究了南京市鼓楼区9个老旧小区老年人户外步行活动的特征,提出最优步行距离的概念及其计算方法用于描述特定老年人群体户外活动的水平,对老年人群体的户外活动步行距离进行量化,并以此为基础建立社区老年人户外活动休息点的分布模型,对9个小区休息点的理想分布进行计算,结果表明,该模型有利于客观地评价城市老旧小区中老年人户外活动休息空间的建设状况,有利于快速发现建成小区中休息点分布的不足,有利于直观预测规划设计中的老年人户外休息空间配置水平。