基于普通物理分析LIGO引力波数据

LIGO小组首次直接探测到双黑洞并合过程中产生的引力波辐射,打开了观测宇宙的一个全新窗口.本文利用牛顿力学,量纲分析,以及将引力波与电磁波类比等方法分析了LIGO小组观测到的引力波数据.这些简单的分析能够解释LIGO数据的主要物理结论,估算结果在数量级上与LIGO数据基本一致.本文对黑洞质量,引力波源到地球的距离,双黑洞并合前的初始距离,以及辐射的总能量等参数的估算与LIGO和VIRGO小组给出的结论基本一致.(2017美国物理教师协会)     

Li~+对硅酸盐玻璃中Yb~(3+)、Tm~(3+)上转换效率的影响

利用高温熔融法制备了不同Li~+含量的掺杂Yb~(3+)、Tm~(3+)的硅酸盐玻璃样品,玻璃样品在980 nm半导体激光器的泵浦下能够产生477 nm的蓝光和654 nm的红光。由上转换的荧光强度和泵浦功率的双对数拟合直线得到,添加Li~+能够增加上转换过程中Tm~(3+)向上跃迁的几率,Tm~(3+)的3F2和1G4能级的粒子数布居增加,从而提高辐射跃迁的几率。红外光谱和拉曼光谱表明Li~+的添加对玻璃基质的声子能量影响不大,却使得声子态密度减小,使上转换效率提高,从而提高Yb~(3+)、Tm~(3+)在硅酸盐玻璃中的发光强度。     

122~125Sn中子谱因子的实验研究

多个Sn同位素位于慢速中子俘获（s-）过程路径上,其中子谱因子可用于计算ASn（n,γ） A+1Sn直接辐射俘获的天体物理反应率,并可研究Sn同位素对s-过程核合成的贡献。本工作在中国原子能科学研究院HI-13串列加速器Q3D磁谱仪上,对实验室系下8°~66°范围内的122,124Sn（d,p）和（p,d）单中子转移反应角分布进行了测量。利用DWBA理论计算了转移反应角分布,并提取了122-125Sn的基态以及123,125Sn第一激发态的中子谱因子。其中,122Sn和124Sn的基态中子谱因子是首次从实验上获得。由于本工作成功鉴别开了123,125Sn的基态和第一激发态的效应,因此给出的谱因子比前人的结果更可信。Several Tin isotopes are on the path of slow neutron capture (s-) process, and the direct components of (n, γ) reactions can be derived from their neutron spectroscopic factors. In the present work, the angular distributions of 122,124Sn(p, d) and (d, p) reactions are obtained using the high-precision Q3D magnetic spectrograph in Beijing HI-13 tandem accelerator in China Institute of Atomic Energy. The distorted-wave Born approximation (DWBA) calculations are performed to extract the neutron spectroscopic factors of the ground state of 122-125Sn and the first excited state of 123,125Sn. The neutron spectroscopic factors of the ground state of 122Sn and 124Sn are firstly obtained in this work. As the events of the ground state and first excited state of 123,125Sn can be distinguished clearly by our experiment, the neutron spectroscopic factories of 123,125Sn are more reliable.     

Measurement of Angular Distribution for the ^8Li（p,d）^7Li Reaction

The ^8Li（p, d）^7 Li reaction plays an important role in the inhomogeneous Big Bang nucleosynthesis and in the seed-nuclide production phase for the r-process. For the first time, its angular distribution at backward angles was measured in inverse kinematics at Ec.m.=4.0 MeV by using an ^8Li secondary beam. The result of measurement includes the contributions of ^8Li（p, d0）^7Li and ^8Li（p, d1）^7Li^＊. The ^8Li（p, d0）^7Li component is estimated to be 40%-58% in the mixture angular distribution by analysing the measured result.     

基于特征Petri网建模的冷水机组故障诊断系统

冷水机组是建筑物中空调系统重要的制冷设备,它的运行状态直接关系到建筑物暖通空调系统运行的性能和稳定性,其故障诊断问题一直受到广泛关注.将特征建模方法引入到冷水机组的故障诊断技术中,并采用模糊Petri网技术实现建模.利用Petri网进行知识表示及推理的矩阵运算算法,描述冷水机组故障征兆与特征参数的关系.运用所提出的诊断系统,不但可以充分利用各特征参数的信息资源进行故障判断,而且可根据冷水机组能效指标COP对故障诊断结果进行综合诊断,有利于冷水机组高效运行.实验结果验证了该故障诊断系统的可行性和准确性.     

Angular distribution of ~6He+p elastic scattering

The angular distribution of ¹H(⁶He,p)⁶He elastic scattering has been measured at E_c.m.=4.3 MeV by using a thick-target inverse kinematic method. The experimental differential cross sections are reproduced by the distorted-wave Born approximation calculation utilizing the CH89 global optical potential parameter set. The real part of CH89 is reduced comparing with other potentials, which may be attributed to the couplings necessary for the weakly bound nuclei.     

Excited States in ^18Ne Studied via ^17F＋p

The elastic resonance scattering of ^17F＋p is studied in inverse kinematics via a thick-target method. The excitation function for ^17F＋p elastic scattering is obtained within the energy interval of Ec.m ≈ 0.4-1.7 MeV. The experimental excitation function is analyzed with a multilevel R-matrix code MULTI7, and the proton widths are deduced. The α decay from 6.15 MeV 1- state in 18Ne is observed, which is critical to the 14O（α, p）17F reaction as the main breakout route from CNO cycle to rp-process in supernovae and x-ray bursts.     

串列加速器次级束流线上的核结构研究

利用北京串列加速器次级束流线产生的放射性离子束开展了核结构和核天体物理的实验研究, 在晕核、核谱因子和辐射俘获反应等领域取得了一些重要的研究成果. 本文简要概述了基于该束流线的核结构实验研究.     

New determination of the ~7Be ground state spectroscopic factor and the ~6Li(p,γ)~7Be astrophysical S(E) factors

The 'lithium problem, in Big Bang nucleosynthesis(BBN) has recently focused on reactions involving ~7 Be.The ~6 Li(p,γ)~7 Be reaction can provide us not only with information about ~6 Li destruction but also with information about ~7 Be production. In the present work, the proton spectroscopic factor in ~7 Be is extracted to be 0.70 ± 0.17 from the angular distribution of ~7 Be(d, ~3 He)~6 Li at E_(c.m.) = 6.7 MeV. This value is then used to compute the direct component of the astrophysical ~6 Li(p,γ)~7 Be_(g.s.) S(E) factors and determine the resonance parameters from the total S(E) factors.