Hadron multiplicities in p＋p and p＋Pb collisions at the LHC

Experiments at the Large Hadron Collider（LHC） have measured multiplicity distributions in p＋p and p＋Pb collisions at a new domain of collision energy.Based on considering an energy-dependent broadening of the nucleon＇s density distribution,charged hadron multiplicities are studied with the phenomenological saturation model and the evolution equation dependent saturation model.By assuming the saturation scale has a small dependence on the 3-dimensional root mean square（rms） radius at different energy,the theoretical results are in good agreement with the experimental data from CMS and ALICE collaboration.The predictive results in p＋p collisions at √s = 14 TeV of the LHC are also given.     

基于改进遗传算法的核磁共振成像主磁体形状优化

针对核磁共振(NMR)成像永磁型主磁体极靴的形状优化问题，应用磁场数值分析和形状优化的理论和方法。探讨了大空间内磁场均匀的技术．以改进的遗传算法作为优化设计中搜索最优方案的工具，达到了在较大空间内磁场相对均匀的目的。     

谐波垫补原理及其在加速器常规磁铁设计与磁场垫补中的应用

加速器常规磁铁磁场质量评估通常表示为工作气隙好场区内高阶磁场占主磁场的相对含量,它通常要求在10^-4量级内。这些高阶磁场来源于磁极的有限长度与宽度和极面设计参数选择产生的若干过大的系统高阶磁场偏差及加工与材料的不理想等因素产生的若干过大的随机高阶磁场偏差。这些偏差均会导致磁场质量变坏。谐波垫补法针对每个过大的高阶磁场利用磁极形位改变对磁场的扰动效应产生一与现存过大高阶磁场大小相当但符号相反的高阶磁场,用来抵消现存的过大的高阶磁场,达到根本改善磁场质量的目的。本文分析了谐波垫补原理,并具体分析了它们在二极磁铁和四极磁铁设计与磁场垫补中的应用。     

Gluon saturation and net-proton spectra in relativistic nucleus-nucleus collisions

By means of the AKK08 fragmentation function, the net-proton transverse momentum （pT） spectra in A＋A collisions are studied with two phenomenological models based on the Color Glass Condensate formalism. After a χ2 analysis of the experimental data from B