手征对称性动力学破缺和铜氧化物超导体相变的三维量子电动力学研究

利用三维量子电动力学理论中的Dyson-Schwinger方程方法, 研究了零温情况下平面铜氧化合物超导体的反铁磁相和d波超导相之间的相变. 通过在朗道规范下近似解析求解和数值求解完全耦合的Dyson-Schwinger方程、并将所得结果与1/N展开方法的结果相比较, 发现在半填充准费密子味道数约小于等于4的情况下, 通过手征对称性自发破缺, d波超导相可以演化到反铁磁相, 并且反铁磁相有可能与d波超导相共存. 通过进一步比较不同相的压强, 还说明反铁磁与d波超导共存相为稳定相, 从而反铁磁相确实可以与d波超导相共存.     

Valence Quark Ratio in the Proton

Beginning with precise data on the ratio of structure functions in deep inelastic scattering（DIS） from ³ He and ³ H, collected on the domain 0.19 ≤ xB≤ 0.83, where xBis the Bjorken scaling variable, we employ a robust method for extrapolating such data to arrive at a model-independent result for the xB= 1 value of the ratio of neutron and proton structure functions. Combining this with information obtained in analyses of DIS from nuclei, corrected for target-structure depen...     

La0.67Ba0.33MnO3薄膜的激光辐照效应研究

利用脉冲激光沉积技术在LaAlO₃（00l）单晶衬底上制备了La_067Ba_033MnO₃薄膜,研究了CO₂激光辐照对La_067Ba_033MnO₃薄膜的微结构和磁电性能的影响.结果表明,经激光辐照后,La_067Ba_033MnO₃薄膜的结晶性增强,薄膜应变减小;薄膜表面形貌由“岛状”结构变为“平原"结构,且粗糙度大大降低;同时,薄膜的饱和磁化强度、铁磁居里温度、金属—绝缘态转变温度和磁电阻增大,而矫顽场和电阻率减小.根据对传统退火效应的分析和理论计算,认为激光辐照导致的表面微结构的变化以及薄膜的氧含量和均匀性的提高对La_067Ba_033MnO₃薄膜的磁电性能的改善与优化密切相关. 关键词： 庞磁电阻 激光辐照 脉冲激光溅射沉积     

具有氧化孔径层的方柱形微腔半导体激光器理论模型

对于具有大折射率衬比的氧化孔径层的方柱形垂直腔面发射微腔半导体激光器,基于Maxwell方程组的矢量解,推导了用于计算激光器阈值增益的理论模型,为数值模拟和微腔半导体激光器的最佳设计提供了理论依据.     

Regarding the Distribution of Glue in the Pion

Understanding why the scale of emergent hadron mass is obvious in the proton but hidden in the pion may rest on mapping the distribution functions(DFs) of all partons within the pion and comparing them with those in the proton;and since glue provides binding in quantum chromodynamics,the glue DF could play a special role.Producing reliable predictions for the proton’s DFs is difficult because the proton is a three-valence-body bound-state problem.As sketched herein,the situation for the pion,a t...     

Drawing insights from pion parton distributions

A symmetry-preserving continuum approach to the two valence-body bound-state problem is used to calculate the valence,glue and sea distributions within the pion;unifying them with,inter alia,electromagnetic pion elastic and transition form factors.The analysis reveals the following momentum fractions at the scale ζ2:=2GeV:〈xvalence〉=0.48(3),〈xglue〉=0.41(2),〈xsea〉=0.11(2);and despite hardening induced by the emergent phenomenon of dynamical chiral symmetry breaking,the valence-quark distribution function,q^π(x),exhibits the x≈1 behaviour predicted by quantum chromodynamics(QCD).After evolution to ζ=5.2 GeV,the prediction for q^π(x)matches that obtained using lattice-regularised QCD.This confluence should both stimulate improved analyses of existing data and aid in planning efforts to obtain new data on the pion distribution functions.     

基于掩膜的光场成像仿真及采样研究

从原理上分析了掩膜的光场成像特点,通过建立光场成像的计算机仿真模型,模拟四维光场的获取,并通过数字对焦算法获得离焦物体的清晰图像.同时利用采样定理分析了孔径采样密度对数字对焦图像的影响,计算出合适的采样间隔对仿真模型的复杂度进行优化.     

有机溶剂中C_(60)荧光的研究

本文研究了C6 0 溶于有机溶剂时 ,荧光能级的变化和荧光强度的大幅度增强。通过拉曼光谱结果显示 ,发现C6 0 分子与溶剂分子之间没有发生显著的化学反应。     

Exploring the light-quark interaction

Two basic motivations for an upgraded JLab facility are the needs： to determine the essential nature of light-quark confinement and dynamical chiral symmetry breaking （DCSB）; and to understand nucleon structure and spectroscopy in terms of QCD＇s elementary degrees of freedom. During the next ten years a programme of experiment and theory will be conducted that can address these questions. We present a Dyson- Schwinger equation perspective on this effort with numerous illustrations, amongst them： an interpretation of string~breaking; a symmetry-preserving truncation for mesons; the nucleon＇s strangeness σ-term; and the neutron＇s charge distribution.     

基于掩膜的光场成像仿真及采样研究

从原理上分析了掩膜的光场成像特点,通过建立光场成像的计算机仿真模型,模拟四维光场的获取,并通过数字对焦算法获得离焦物体的清晰图像.同时利用采样定理分析了孔径采样密度对数字对焦图像的影响,计算出合适的采样间隔对仿真模型的复杂度进行优化.