Projectile fragment emission in the fragmentation of ~(56)Fe on C,Al and CH_2 targets at 471 A MeV

The emission angle and the transverse momentum distributions of projectile fragments produced in the fragmentation of ⁵⁶Fe on CH₂, C and Al targets at 471 A MeV are measured. It is found that for the same target, the average value and width of the angular distribution decrease with an increase of the projectile fragment charge; for the same projectile fragment, the average value of the distribution increases and the width of the distribution decreases with increasing the target charge number. The transverse momentum distribution of a projectile fragment can be explained by a single Gaussian distribution and the averaged transverse momentum per nucleon decreases with the increase of the charge of projectile fragment. The cumulated squared transverse momentum distribution of a projectile fragment can be explained well by a single Rayleigh distribution. The temperature parameter of the emission source of the projectile fragment, calculated from the cumulated squared transverse momentum distribution, decreases with the increase of the size of the projectile fragment.     

构造直角三角形解题例析

一、图形中有圆的直径时,可考虑完善图形,构造直径上的圆周角例1 设MN是O的直径,P、C为圆上任意两点,连结PM、PN。过C作MN的垂线与MN、MP和NP的延长线交于A、B、D,     

对能对弹核碎裂反应截面的影响

运用改进的量子分子动力学(ImQMD)模型嫁接GEMINI统计衰变模型对400 AMeV 36Ar与C、Al、Cu、Pb的弹核碎裂反应截面的奇偶效应进行了理论分析。分析结果表明,弹核碎裂电荷反应截面的奇偶效应产生在初级碎块的退激发过程中,而且退激发过程中的对能在奇偶效应的产生中起着重要作用。如果不考虑对能,弹核碎裂电荷反应截面的奇偶效应将消失。同时由于对能的作用使得弹核碎裂的中子反应截面也表现出明显的奇偶效应。     

3.7A GeV 16O-Em作用中的间歇行为

对3.7A GeV ¹⁶O-Em作用产生的慢粒子标度阶乘矩分布进行研究, 得出间歇指数随矩阶数的增加而增加, 随靶核质量的增加而减小; 反常分形维数 随q的增加而增加; 对于每一个q值, d_q随平均多重数的增加而减小, 表明在3.7A GeV ¹⁶O-Em作用中多粒子产生具有自相似级联的性质.     

Investigation of self-affine multiplicity fluctuations of proton emission in 84Kr-AgBr interactions at 1.7 A GeV

Self-affine multiplicity scaling is investigated in the framework of a two-dimensional factorial moment methodology using the concept of the Hurst exponent （H）. Investigation of the experimental data of medium-energy knocked-out target protons in ^84Kr-AgBr interactions at 1.7 AGeV reveals that the best power law behavior is exhibited for H=0.4, indicating a self-affine multiplicity fluctuation pattern. Multifractality among the knocked-out target protons is also observed in the data.     

Intermittent type fluctuation of target fragments produced in 16O-AgBr interactions at 4.5 AGeV/c

A study of intermittency of target associated fragments produced in the interactions of ¹⁶O-AgBr at 4.5 AGeV/c with nuclear emulsion using the method of factorial moments, F_q, has been performed. The dependence of the moments on the number of bins M is found to follow a power law behavior for the experimental data in terms of new scaled variable χ(z) suggested by Bialas and Gazdzicki. The anomalous dimensions, d_q, increase linearly with the order of moments, q. This observation indicates the association of multifractility with production mechanism of target associated fragments.     

通过联想巧解几道竞赛题

一、巧构特殊图形妙借面积公式[例1](第15届全俄数学竞赛题) 设x、y、z都是小于1的正实数. 求证:x(1-y) y(1-z) z(1-x)<1. 分析本题是证代数不等式,若按代数证法,较为繁冗.我们观察到:待证式左端为轮换对称式及数字“1”,可联想到构造一个边长为     

60 A GeV16O原子核在核乳胶中的电磁离解

对60 A GeV16O在原子核乳胶中的电磁离解现象首次进行了高统计的研究,得到电磁离解截面随束流能量的增加而增加,射弹碎片电荷分布和200 A GeV16O在乳胶中电磁离解的电荷分布一致,但电荷为3≤Z≤5的射弹碎片的发射概率低于200 A GeV能区,这些特点和Weiszacker和Williams的经典电磁理论模型计算结果一致.60 A GeV16O电磁离解下各反应道出现的概率和200 A GeV能区结果基本一致,但同14.6 A GeV能区的结果不同,在60 A GeV能区16O电磁离解主要是由电偶及电四激发引起的巨偶极和巨四极共振及准氘核效应过程所致,这一点可以通过电磁离解下质子的多重数分布得到定性解释.电磁离解下α射弹碎片的分布同非弹核作用下α碎片的分布规律不同,说明α碎片的产生机制不同.     

Intermittent type fluctuation of target fragments produced in ^16O-AgBr interactions at 4.5 AGeV/c

A study of intermittency of target associated fragments produced in the interactions of ~(16)O- AgBr at 4.5 AGeV/c with nuclear emulsion using the method of factorial moments, F_q,has been performed. The dependence of the moments on the number of bins M is found to follow a power law behavior for the experimental data in terms of new scaled variableχ(z)suggested by Bialas and Gazdzicki.The anomalous dimensions, d_q,increase linearly with the order of moments,q.This observation indicates the association of multifractility with production mechanism of target associated fragments.     

Helium production from 84Kr-- and 197Au--emulsion interactions at high energies

The properties of the relativistic helium fragments produced in interactions of 84 Kr at 1.8 A GeV and 197 Au at 10.7 A GeV in emulsion are investigated. The experimental results are compared with those obtained from various projectiles with emulsion collisions at different energies. It is found that the multiplicity distribution of helium projectile fragments (HPFs) is well described by the Koba-Nielsen-Olesen (KNO) scaling presentation. The second Mueller moment f 2 of the HPF multiplicity distribution is independent of the projectile energy for the same projectile, but it is dependent on the projectile mass number. The value of f 2 increases with the increase of projectile mass number A p . The negative value of f 2 , when A p < 69, means that the emission of HPFs is anticorrelated, but positive value of f 2 , when A p > 69, refers to that the emission of HPFs is correlated. The non-zero f 2 moment in this experiment implies the strong correlation existing between the HPFs.