Uncertainties of critical temperatures based on higher-order fluctuations of the largest fragment charge

The new signature of liquid-gas phase transition has been well indicated by the higher-order fluctuations of the largest fragment charge,but the uncertainties of critical temperatures based on this signature have not been revealed.This study extracts the critical temperatures of liquid-gas phase transition in nuclear reactions and investigates their uncertainties.Utilizing the isospin-dependent quantum molecular dynamics model in conjunction with the statistical model GEMINI enables us to descri...     

注入器二极管区约束磁场的匹配设计研究

从分析影响注入器低能强流电子束稳定传输的主要因素出发，提出了注入器二极管区约束磁场匹配设计条件：阴阳极间足够高的磁场梯度和阴极面零磁场发射。阐述了满足匹配条件的磁场配置的设计方法，并利用数字模拟对设计方法进行了验证。     

附面层中马蹄形旋涡的实验研究

本文用烟流显示和热线方法研究附面层中马蹄形旋涡的形态、生成频率、配对和涡系之间的相互作用。     

间隙长度对气体火花开关静态性能的影响

针对快放电直线脉冲变压器驱动源初级储能开关,调节开关气压,进行相同自击穿电压下不同间隙长度的开关自击穿实验。通过监测自击穿电压分布规律变化,研究开关间隙长度对开关自击穿特性的影响。结果表明,当开关间隙长度较大时,电极表面粗糙度较小,表明电极烧蚀程度较低。开关间隙长度为6 mm时,开关自击穿电压分散性达到最小,自击穿电压分布符合高斯函数,间隙长度大于6 mm时自击穿电压分布符合极限函数。适当增加开关间隙长度使自击穿电压分布失去对称性,有利于开关在低欠压比下获得更好的静态性能。针对电极结构,选择开关间隙长度为6~9 mm时能够获得最佳的静态性能。初步分析,引起开关自击穿电压分布发生改变的原因是电场强度的改变对阴极电子发射产生了影响。     

FLTD系统放电开关自击穿性能优化

针对快前沿直线脉冲变压器驱动源(FLTD)系统中放电开关自击穿性能劣化的问题,模拟计算了带电线缆、FLTD模块结构对开关间隙电场分布的影响规律,研究分析开关自击穿性能下降的主要原因,开展了电晕针均压和电阻均压两种方式下开关自击穿性能对比实验,获得了不同电晕针长度、不同阻值开关自击穿电压的变化规律：两种均压方式下开关自击穿电压分别提高3.2%和4.3%。FLTD系统中放电开关有均压措施的情况下,系统自击穿电压提高8.9%,自放电概率降低60%,系统短路输出电流的稳定性明显提高,电流幅值提高8.1%,标准偏差减小30.8%。     

UNCONVENTIONAL HAMILTON-TYPE VARIATIONAL PRINCIPLES FOR DYNAMICS OF REISSNER SANDWICH PLATE

According to the basic idea of classical yin-yang complementarity and modern dual-complementarity,in a simple and unified way proposed by Luo(1987),some uncon- ventional Hamilton-type variational principles for dynamics of Reissner sandwich plate can be established systematically.The unconventional Hamilton-type variation principle can fully characterize the initial-boundary-value problem of this dynamics.In this pa- per,an important integral relation is given,which can be considered as the generalized principle of virtual work in mechanics.Based on this relation,it is possible not only to obtain the principle of virtual work in dynamics of Reissner sandwich plate,but also to derive systematically the complementary functionals for five-field,two-field and one-field unconventional Hamilton-type variational principles by the generalized Legender trans- formations.Furthermore,with this approach,the intrinsic relationship among the various principles can be explained clearly.     

Unconventional Hamilton-type variational principles for nonlinear elastodynamics of orthogonal cable-net structures

According to the basic idea of classical yin-yang complementarity and modem dual-complementarity,in a simple and unified new way proposed by Luo,the unconven- tional Hamilton-type variational principles for geometrically nonlinear elastodynamics of orthogonal cable-net structures are established systematically,which can fully charac- terize the initial-boundary-value problem of this kind of dynamics.An important in- tegral relation is made,which can be considered as the generalized principle of virtual work for geometrically nonlinear dynamics of orthogonal cable-net structures in mechan- ics.Based on such relationship,it is possible not only to obtain the principle of virtual work for geometrically nonlinear dynamics of orthogonal cable-net structures,but also to derive systematically the complementary functionais for five-field,four-field,three-field and two-field unconventional Hamilton-type variational principles,and the functional for the unconventional Hamilton-type variational principle in phase space and the poten- tial energy functional for one-field unconventional Hamilton-type variational principle for geometrically nonlinear elastodynamics of orthogonal cable-net structures by the general- ized Legendre transformation given in this paper.Furthermore,the intrinsic relationship among various principles can be explained clearly with this approach.     

关于线粘弹性动力学中各种变分原理

本文提出一条简单而统一的新途径,系统地建立了线粘弹性动力学中各种简化Gurtin型变分原理,文中首先给出一个很有用的以卷积表示的积分关系式,然后从该式出发,系统地导出成互补关系的五类变量、四类变量、三类变量、二类变量及一类变量简化Gurtin型变分原理,并清楚地阐明它们之间的内在联系,而且,还发现当前在国际上有广泛影响的力学变分原理方面的名著[1]及文[2]中,所给出的四个变分原理的泛函式均有误.本文除给出这四个正确的泛函式外,还建立了一些新的更一般广义变分原理。