通讯网络的极小费用树

本针对MCM91问题B所给的9个通讯站。建立路径最短的数学模型，然后根据虚设站与路径的相互关系，以合并或分解虚设站为线索逐渐修改模型，最后确定的模型费用为134．84。比美国马里兰州里斯勃莱州立大学数学科学系(MCM的Director)B．A．Fusaro提供的原的费用少1．05，本新颖之处是改进图论中求最小生成树的方法，创连性地给出一个解决实际问题的新思路。     

国际次声监测研讨会

全面核禁试条约第三届全球次声监测工作研讨会于1997年8月25至28日在美国新墨西哥州西班牙式的古城圣菲举行．会议云集了中国、美国、法国、俄罗斯、阿根廷、澳大利亚等5大洲12个国家61位活跃在次声学科领域的研究人员、政府官员以及联合国临时技术秘书等要员，围绕着全球次声监测中的7个专题进行报告和讨论，它们依次为：欢声阵的设计和信号处理，次声阵性能和减噪设备；法国欢声监测系统，国际次声监测系统60个站网的能力模型，对流层风对长距离次声传播的影响，高空风对次声同性能的影响，渗透管的特性以及对次声监测的减噪作用，欢声减噪器；爆炸检测，声遥感技术对爆炸源能量的估计，小当量地下，地面和近地面爆炸远距离声传     

有向树的几个组合问题

本文计算有n个结点,m个叶子和具有叶路径长度为s的有向树的个数,以及n个结点,结点路径总长度为r的有向树个数。从而,解决了有向树的叶路径总长度,结点路径总长度的计算问题。     

拆边法求最短路径

本文利用局部比较法 ,在图中定义子图、无效路径、以及可去边 .利用推导的有关定理 ,拆去可去边 ,利用最短路径相同的等价性 ,达到化简图 ,从而求出最短路径     

Multi-path propagation of acoustical wave and time reversal field in a solid plate

The multi-path effect of the acoustical wave in a solid plate is studied. The multireflection and wave conversion of the cylindrical compressional and shear waves, which are excited by an infinite strip on a free surface of the solid plate, are analyzed thoroughly by the far-field approximation method. The concise analytical representations of the cylindrical waves are obtained. The time reversal processing is then applied to the propagation of the cylindrical waves and analyzed theoretically and experimentally. It is shown that the waves coming from different array elements and different paths all arrive at the original place after the time reversal operation. It indicates that the time reversal can compensate automatically the wave aberration caused by the multi-path effect. The self-adaptive focusing of the time reversal field is also analyzed quantificationally by the focusing gain and the ratio of the principal to the second lobe. The effects of the focus position and the aperture of the transducer array on the focused field are also investigated. It shows that theoretical and experimental results are consistent to each other very well.     

Investigation of the mean free path of projectile fragments produced in 16O－Em collision at 60 A GeV

Results are presented for an investigation of the mean free path of projectile fragments with charge 3≤Z≤8, produced by 60 A GeV {}^{16}O in nuclear emulsion. No dependence of mean free path on the distance from the point of the fragment emission is observed and our result is consistent with the nonexistence of anomalons.     

Temporal Skewness of Electromagnetic Pulsed Waves Propagating Through Random Media with Ebedded Irregularity slab

Electromagnetic pulsed waves can be distorted in the propagation through random media,and their energy distributions change along the leading and trailing edge of the waveform,which can be presented by the temporal skewness.The skewness presents asymmetry and is treated by the third-order temporal moment,in which an analytic solution for the two-frequency mutual coherence function is obtained recently.Then,transionospheric pulses are discussed in details,Both theoretical analysis and numerical computation indicate that the contributions from scattering and dispersion of irregularities dominate over those of background,so the latter can be neglected in most cases.Also,the temporal skewness of a transionopheric pulse is negative and energy is shifted to the leading edge.     

Dependence of Quark Effective Mass on Gluon Propagators

Based on Dyson Schwinger Equations （DSEs） in the “rainbow” approximation, the dependence of quark effective mass on gluon propagator is investigated by use of three different phenomenological gluon propagators with two parameters, the strength parameter x and range parameter △. Our theoretical calculations for the quark effective mass Mf（p^2）, defined by the self-energy functions Af（p^2） and Bi（p%2） of the DSEs, show that the dynamically running quark effective mass is strongly dependent on gluon propagator. Therefore, because gluon propagator is completely unknown, the quark effective mass cannot be exactly determined theoretically.     

路径对摩擦力做功的影响

本文通过讨论两种临界情况下摩擦力所做的功的变化情况，进一步阐明非保守力做的功与路径有关．     

A Continuation Method of Parameter Inversion for Non-Equilibrium Convection-Dispersion Equation

Based on the homotopy mapping, a globally convergent method of parameter inversion for non-equilibrium convection-dispersion equations （CDEs） is developed. Moreover, in order to further improve the computational efficiency of the algorithm, a properly smooth function, which is derived from the sigmoid function, is employed to update the homotopy parameter during iteration. Numerical results show the feature of global convergence and high performance of this method. In addition, even the measurement quantities are heavily contaminated by noises, and a good solution can be found.