三结点hierarchical晶格上具有三体相互作用伊辛模型的临界行为

本文运用严格重整化交换研究了三结点hierarchical晶格上具有三体相互作用的伊辛模型。研究表明,与布喇菲晶格上的情况一样,最近邻二体相互作用伊辛模型与三体相互作用伊辛模型(Baxter-Wu模型)属于不同的普适类。     

重新初始化的LS方法跟踪二维可压缩多介质流界面运动

 用非耦合求解方法计算Level Set函数方程与流体力学方程组，应用重新初始化的Level Set函数确保距离函数性质，流体力学方程组采用二阶精度多介质流波传播差分格式计算，重新初始化方程采用五阶WENO格式计算。并给出了二维可压缩多介质流界面运动的计算结果。     

复合功能布的动态力学性能及本构关系

针对复合功能布的物理特性,利用材料试验机和分离式Hopkinson压杆装置,展开了准静态和动态条件下单层和双层复合功能布材料的单轴抗压实验,获得了两种材料在不同应变率下的应力应变曲线和材料的失效应力、应变.实验结果表明:复合功能布的动态失效强度明显高于准静态失效强度,而且随着应变率的增加其动态失效强度呈现增加的趋势,即该材料具有明显的应变率硬化效应.对应力应变曲线进行拟合,给出了材料的动静态粘弹性本构关系.并对复合功能布在不同应变率下的失效应变及材料的损伤结果进行了初步的分析.     

Mutual Information of Pauli Channels with Correlated Noise

A general formula for the mutual information of the Paufi channels with memory modelled by correlated noise is derived. It is shown that the mutual information depends on the channel shrinking factor, the input state parameter and the channel memory coefficient. The analyses based on the general formula reveal that the entanglement is always a useful resource to enhance the mutual information of some Pauli channels, such as the bit flip channel and the bit-phase flip channel. Our analyses also show that the entanglement is not advantageous to the reliable transmission of classical information for some Pauli channels at any time, such as the phase flip channel and the phase damping channel.     

状态空间约束下一个最大值原理互补松驰强形式的分析

分析了约束条件不显式地包含控制变量时的有界状态变量约束条件下,一种应用最大值原理求解最优控制问题的方法所要求的互补松驰条件的强形式.在最优轨线从约束条件起作用到不起作用的连接点,该强形式条件不是总成立的,此时应使用互补松驰条件的一般形式来求解.算例分析证明了上述结论.     

Time-Resolved Femtosecond Degenerate Four-Wave Mixing in LiNbO3：Fe,Mg Crystal

Forward degenerate four-wave mixing （DFWM） processes are investigated with a femtosecond pulsed laser in lithium niobate crystal doubly-doped with magnesium and iron （LiNbO3：Fe, Mg）. The pulse energy dependence reveals a pure third-order nonlinear response, and the third-order nonlinear susceptibility x^（3） in the material is evaluated to be 4.96 × 10^-13 esu. The time-resolved DFWM process shows a response time of x^（3） shorter than 100fs, which is due to the nonresonant electronic nonlinearities. Our results indicate that LiNbO3 crystals have potentials for ultrafast real-time optical processing systems, which require a large and fast x^（3） optical nonlinearity.     

离子型稀土矿放射性核素迁移及处理研究进展

离子型稀土矿伴生一定量的铀、钍等天然放射性核素。采用原地浸矿工艺提取稀土时,部分放射性核素与稀土元素一同浸出,并随着稀土的冶炼过程富集在多种工序产生的废渣中,使得铀、钍、镭的放射性活度浓度大于1000 Bq·kg^-1,属于低放射性废渣。随着渣量的不断增加,该类低放射性废渣的安全处置已成为困扰行业发展的难题。本文阐述了中国对放射性辐射环境管理、放射性废物存储及处理要求的发展过程,总结了放射性核素铀、钍、镭在离子型稀土矿冶炼过程中的迁移富集规律,综述了溶剂萃取法、吸附法处理含放射性废水以及废渣资源化、减量化处理等方面的研究进展,分析了离子型稀土矿放射性核素处理存在的问题,最后提出了在放射性核素的源头减量化、废渣资源化、残渣安全化处置等方面的一些技术发展建议。     

Mechanical Properties of Sialic Foamed Ceramic and Applications in Defense Structure

Mechanical properties of a closed-cellular sialic foamed ceramic are investigated by compressive tests. The sialic foamed ceramic under uniaxial stress compression shows brittleness and the flow stress increases with the strain rate. The engineering stress-engineering strain curve under uniaxial strain compression could be divided into three stages： linear elasticity, collapsed plateau and densification. The unloading elastic modulus, Poisson ratio and energy absorption ability are discussed. Shelly cellular material made by sialic foamed ceramic is applied into the stress distribution layer in the defense structure. Field explosion experiments are performed for the sand based stress distribution layer and shelly cellular material based layer. Compared with sand, the shelly cellular material reduces the peak stress of the blast wave.     

近化学计量比掺镁铌酸锂晶体的抗光折变性能

应用气相传输平衡技术,我们获得了3种近化学计量比掺镁铌酸锂晶体,晶体的掺镁量接近我们以前提出的第二阈值.在我们实验室所能达到的最大光强26 MW/cm2照射下,在所有近化学计量比掺镁铌酸锂晶片中没有观察到光斑畸变,该光强比同成分铌酸锂晶体所能承受的光强高6个量级,为目前已报道的铌酸锂晶体之最.应用双光束全息写入法测得掺1.0 mol; Mg近化学计量比铌酸锂晶体的光折变饱和值仅有4.6×10-7,比同成分铌酸锂晶体小两个量级,从已有实验数据推测,该晶体的抗光折变能力应当比同成分铌酸锂晶体高9个量级以上.     

微波分光仪角锥喇叭天线的优化

简述了角锥喇叭天线的设计原理,对微波分光仪角锥喇叭天线进行了优化设计.结果表明,优化后的角锥喇叭天线单向传输性与增益均得到改善.