On ηc line shape in charmonium transitions

The line shapes to observe ηc in charmonium transitions, I.e.,ψ(2S), J/ψ→γηc, are investigated. The ηc line shapes in exclusive decays or by observing the inclusive photon spectrum are given. The sensitivities to measure the ηc resonance parameters are also evaluated. With more than two thousand ηc events observed, the precision of the ηc decay width measurement will be improved by better than 3%. However, the uncertainties associated with the ηc modified line shapes will dominate the systematic errors and this will prohibit precision mass and width measurements.     

VDSL2信道建模与仿真

从传输线理论出发，运用基尔霍夫定律建立了传输线方程．应用传输线方程建立双绞线信道模型，并对该模型在0～30MHz频段进行了仿真分析，且将仿真结果一与法国电信研发部的实测数据进行了比较，结果证明模型与实测数据一致，因此表明所建模型符合实际情况．该模型的建立对VDSL2系统研究、性能分析和系统设计有着重要的作用和意义．     

金激光等离子体的空间分辨X射线发射谱及其应用

在星光II激光装置上,采用PET平面晶体谱仪与宽20μm的狭缝构成一维空间分辨光谱测量系统,对金平面靶激光等离子体进行观测,获得了沿靶面法向一维空间分辨的金M带发射谱。在实验谱中观察到了Au元素类Ni离子的电四极跃迁线3p63d10(1S0) 3p53d104d(3/2,5/2)J=1。利用电四极跃迁线对电子密度的敏感特性,开展了金激光等离子体电子密度诊断的尝试,确定出利用该谱线进行电子密度诊断的有效范围大致在1019～4.5×1021cm-3之间。     

Matrix Line in Pulsed Electron-Nuclear Double Resonance Spectra

The intense line in Mims and Davies electron-nuclear double resonance (ENDOR) spectra due to the hyperfine interactions of an unpaired electron with distant matrix nuclei is shown to originate from a simultaneous inversion of a large number of nuclear spins by a radiofrequency pulse. Theoretical expressions describing the matrix ENDOR effect are derived and verified experimentally.     

平衡子欧拉符号图及符号线图

符号图$S=(S^u,\sigma)$是以$S^u$作为底图并且满足$\sigma: E(S^u)\rightarrow\{+,-\}$. 设$E^-(S)$表示$S$的负边集. 如果$S^u$是欧拉的(或者分别是子欧拉的, 欧拉的且$|E^-(S)|$是偶数, 则$S$是欧拉符号图(或者分别是子欧拉符号图, 平衡欧拉符号图). 如果存在平衡欧拉符号图$S''$使得$S''$由$S$生成, 则$S$是平衡子欧拉符号图. 符号图$S$的线图$L(S)$也是一个符号图, 使得$L(S)$的点是$S$中的边, 其中$e_ie_j$是$L(S)$中的边当且仅当$e_i$和$e_j$在$S$中相邻,并且$e_ie_j$是$L(S)$中的负边当且仅当$e_i$和$e_j$在$S$中都是负边. 本文给出了两个符号图族$S$和$S''$,它们应用于刻画平衡子欧拉符号图和平衡子欧拉符号线图. 特别地, 本文证明了符号图$S$是平衡子欧拉的当且仅当$\not\in S$, $S$的符号线图是平衡子欧拉的当且仅当$S\not\in S''$.     

A Multi‐Electrode Approach for On‐Line Characterisation of Size and Shape

A multi‐electrode approach is proposed for on‐line characterisation of particle size and shape in dilute particulate suspensions. Based on an electrozone principle, the approach uses four electrodes in a tube rather than two electrodes across an aperture employed in conventional methods. The outer two electrodes are used for current injection, while the inner two electrodes yield voltage measurement. A sensor designed in this way can reduce errors of false counts and oversizing that may occur in conventional methods, thus providing more accurate particle sizing. It is also possible to use the signal slope along with signal peak for particle size and shape characterisation. Both theoretical modelling and experiments were conducted, showing that particle aspect ratio along with particle diameter can be obtained, for example, for cylindrical particles.     

T = 0 versusT = 1 pairing in 0(36) limit of IBM-4 for heavyN = Z nuclei

In theO(36) limit of the interacting boson model including spin-isospin degrees of freedom (IBM-4), starting with a group chain that preservess andd boson spins and isospins together with a simple mixing hamiltonian, it is shown that the model generates, for heavyN =Z nuclei, even-even to odd-odd staggering in the number ofT = 0 pairs in the ground states for moderate difference in the basicT = 0 andT = 1s-boson pair energies; the staggering disappears when the energy difference is large.