CsI(Tl)晶体中反冲Cs和I核Quenching?Factor的测量

许多实验对用CsI(Tl)闪烁晶体作为探测器来寻找和探测暗物质的可行性进行了研究.本工作利用8MeV单能中子轰击CsI(Tl)晶体探测器来研究Cs核和I核的QuenchingFactor.在数据处理中,运用脉冲形状甄别(PSD)方法来分辨反冲核信号和本底信号.实验结果表明,在7keV到132keV的能区中,Quench ingFactor随着反冲核能量的减少而增加.在探测暗物质的实验中,这一性质对于CsI(Tl)晶体探测器获得较低的能量阈值是很有利的.     

Two-component model of solar plages

By use of the 2-m Mcmath-Pierce telescope at Kitt Peak, the high-quality spectra of a plage with moderate brightness near the center of solar disk were obtained. The data include seven spectral lines, which are Hα, Hβ, CaII H and K lines and the infrared triplet. With the consideration of fine structures of solar plages, a two-component atmospheric model is constructed by keeping the cool component to be the quiet atmosphere. Three cases of the hot component are given for different filling factors where the temperature and density distribution are adjusted in order to reproduce the seven observed spectral profiles. We also briefly discuss the influence of the column density at the base of the corona, m0, and the macro-turbulent velocity on the required filling factor and computed profiles. The two-component model is compared with precious one-component semi-empirical models. The limitation of the model is pointed out and further improvement is indicated.     

激光诱导荧光探测水体中溶解有机物浓度

用Nd∶YAG激光器的三倍频355 nm光作为激发光源,根据激光诱导荧光(LIF)方法激发并探测污染水体的荧光光谱.通过对荧光光谱的分析处理研究归一化荧光强度,即450 nm处水中溶解有机物(DOM)峰与405 nm处水的拉曼峰的比值,反演溶解有机物浓度.用商品腐殖酸和去离子水配置成已知浓度的溶液代替标准DOM溶液进行标定,得到回归方程.结果证明,DOM的归一化荧光强度与水体中DOM浓度有较好的线性关系,因此LIF方法是对大面积水域水质进行动态遥测的较理想方法.     

Instability of quark matter core in a compact newborn neutron star with moderately strong magnetic field

It is explicitly shown that if phase transition occurs at the core of a newborn neutron star with moderately strong magnetic field strength, which populates only the electron’s Landau levels, then in the β -equilibrium condition, the quark core is energetically much more unstable than the neutron matter of identical physical condition.     

Ricci and Matter Collineations of Locally Rotationally Symmetric Space-Times

A new method is presented for the determination of Ricci Collineations (RC) and Matter Collineations (MC) of a given spacetime, in the cases where the Ricci tensor and the energy momentum tensor are non-degenerate and have a similar form with the metric. This method reduces the problem of finding the RCs and the MCs to that of determining the KVs whereas at the same time uses already known results on the motions of the metric. We employ this method to determine all hypersurface homogeneous locally rotationally symmetric spacetimes, which admit proper RCs and MCs. We also give the corresponding collineation vectors. These results conclude a long due open problem, which has been considered many times partially in the literature.     

水平均匀大气中多束光在接收面上的相关性及其对光强起伏的影响

在科尔莫戈罗夫理论的基础上，推广了光束在接收面上相关函数的物理含义。分析了多光束在接收面上的相关性。并在此基础上形成多光束光强起伏方差的解析表达式。分析结果表明，随着信道间距的增加，信道相关性下降。到达接收面的光强起伏方差降低；当信道完全重合，即相关系数变为1时，叠加后的光强起伏方差没有明显降低。与单光束时没有区别；在允许范围内增加光束数目可降低光强起伏。     

(ΩΩ)0+ Dibaryon Productions in Central Au+Au Collisions at RHIC Energy(SNN)= 130 GeV

Based on the measured transverse mass spectra ofπr-, K-, and p at the RHIC energy s()NN = 130 GeV,di-omega productions from baryon-baryon reactions in hadronic matter are studied. Results about the (ΩΩ)0+ numbershow that the deeply bound state (ΩΩ)o+ can be observed at RHIC energies.     

膨胀的热夸克胶子物质的中等质量双轻子的增强

基于一个描述夸克胶子火柱演化的相对论流体力学模型,研究了夸克相、强子相互作用以及非热过程(DrellYan对、粲强子衰变)的中等质量双轻子的产生.发现由于相边对夸克胶子物质演化的影响和RHIC能量核碰撞产生的夸克胶子物质具有高的初始温度,夸克相对双轻子的贡献显著增强,比那些来自强子相互作用的贡献重要,甚至能与来自非热的贡献比较.表明中等质量双轻子的增强是一个在核碰撞中产生了夸克胶子物质的可能信号. 关键词： 夸克-胶子物质 双轻子增强 相对论流体力学模型     

Propagation of mesons in asymmetric nuclear matter in a density-dependent coupling model

We study the propagation of the light mesons σ,ω,ρ, and a₀(980) in dense hadronic matter in an extended derivative scalar coupling model. Within the scheme proposed it is possible to unambiguously define effective density-dependent couplings at the Lagrangian level. We first apply the model to study asymmetric nuclear matter with fixed isospin asymmetry, and then we pay particular attention to hypermatter in β-equilibrium. The equation of state and the potential contribution to the symmetry coefficient arising from the mean-field approximation are investigated. Received: 16 October 2001 / Accepted: 10 January 2002     

海洋激光雷达测量海中悬移质

研制了一套采用倍频YAG激光器的小型海洋激光雷达，用于测量海中悬移质浓度，2000年8月28日至9月5日，该系统安装于“东方红Ⅱ”号右舷下甲板，在渤海海区进行海中悬移质浓度现场测量，通过对18个站位的海洋激光雷达数据分析，获得的表层悬移质浓度与同步测量的海中悬移质浓度结果吻合较好。