部分相干径向偏振光束传输中相干性研究

根据广义惠更斯理论及相干偏振统一理论, 研究部分相干径向偏振光束在自由空间中传输时, 不同参考点处复相干度随传输距离的变化规律. 研究表明, 部分相干径向偏振光束在自由空间中传输, 不同参考点处, 复相干度模值随距离的变化规律有所差别. 当参考点位于原点时, 随着传输距离增大, μ_xx模值及μ_xy模值分布形式不变, 分布范围增大; 当参考点位于x轴上时, μ_xx模值由单峰值向三峰两谷对称形式演化, μ_xy模值由单侧两峰向四峰四谷对称形式演化, 完成演化所需传输距离与参考点距离x轴中心的远近有关, 参考点距离x轴中心越近, 完成演化所需的传输距离越短; 当参考点位于y轴时, 随着距离增大, μ_xx模值分布形式不变, 分布范围增大, μ_xy模值由上侧两峰向四峰四谷对称形式演化, 演化所需传输距离与参考点距y轴中心远近有关, 参考点距y轴中心越近, 完成演化所需的传输距离越短; 当参考点位于其他位置时(非特殊位置), μ_xx模值及μ_xy 模值分布规律, 遵从各自参考点在x轴, y轴上的分布规律的结合即参考点位于其他位置时, μ_xx模值及μ_xy模值分别随距离变化逐渐演化成三峰结构、四峰结构.     

确定等价电子杨盘基的等概率比对方法

给出了等价电子正则杨盘T^［λ］_ig的基本对称算子、完全对称算子概念,同时给出了这些对称算子作用于任一Slater函数_i所产生的根态、生成态概念.由正交归一化杨盘T^［λ］_ie的纵置换算子A^［λ］_ie的构造规则,给出了A^［λ］_ie中存在的对称算子和确定T^［λ］_ie的等概率比对方法,从而基本避免了牵涉到许多算子的极其复杂的代数,给出了求解N值较大的电子系统杨盘基问题的新方法. 关键词： 正则杨盘 对称算子 根态 等概率比对方法     

NFX(X=-1,0,+1)分子离子基态的结构与势能函数

用密度泛函理论的B3LYP方法,分别以6-311++g(df,3pd),6-311g(3d,3p)和6-311++g(3df,3pd)为基函数对NF分子、NF⁺和NF^-离子基态进行几何优化和频率计算,并进行单点能扫描计算.用最小二乘法拟合得到NF^X(X=-1,0,+1)分子离子基态的Murrell-Sorbie势能函数.利用得到的解析势能函数计算出的NF分子和NF⁺离子基态光谱常数(B_e,α_e,ω_e,ω_eχ_e)与实验值符合很好.首次得到NF^-离子基态的光谱常数(B_e,α_e,ω_e,ω_eχ_e)和力常数(f₂,f₃,f₄),为NF-离子基态的后期研究提供理论参考.     

一类奇异复本征方程组的数值计算

利用基本解矩阵法数值求解一类带有奇异点的复本征方程组,并对奇异点的消除和复本征值的确定及数值不稳定性等问题进行了讨论,编制了求解程序代码,并应用于离子温度梯度(ITG模或η_i模)驱动不稳定性研究的数值模拟.实例计算表明,数值结果与理论分析完全吻合.     

周期力调制噪声驱动下单模激光系统的多重随机共振

在周期力调制噪声驱动下单模激光系统的光强方程中加入调幅波, 用线性化近似方法计算了系统的光强关联函数和输出信噪比, 并对信噪比进行数值计算和分析, 发现低频调制频率Ω、高频载波频率ω和周期力频率Ω_λ对系统的输出信噪比有很大的影响. 具体表现为信噪比R 随低频调制频率Ω 的变化过程中出现了多重随机共振和极强的单峰共振, 当Ω << ω 时, 系统出现的是多峰共振, 且随着Ω_λ 增加, 共振峰间的距离增大, 峰值位置不变; 当Ω → ω 时, 输出信噪比R迅速增大, 而Ω_λ 的影响被削弱甚至可以忽略, 多峰共振消失; 当Ω = ω 时, 系统出现了极强的单峰共振. 此外, 信噪比随周期力频率的变化呈现振幅减小的多重随机共振, 而随载流频率的变化出现单峰随机共振.     

稠苯芳环及其烷基质子化学位移的计算

本文提出了予测稠苯芳烃及其衍生物的环上和烷基链上质子化学位移的计算方法。 将稠苯芳环化合物用凯库勒式表示,用下式计算: δ=σ_j.c-c+σ_mi.ci σ_j.c-c为各种乙烯基的效应。σ_mi.ci,为各个苯环的六电子π轨道的净环流效应,其计算式为: σ_m.e=(1/2)^m×1,52 m=n-u m为净环流效应级数,等于质子到该苯环相隔的键数n减其中的顺式键数u。 在菲环和类似菲环的4,5位与9,10位质子需考虑菲环效应。蒄环上的质子需考虑蒄环效应。有取代基需考虑取代基的效应。 计算环上烷基质子的公式: δ=σ_p.CH3+ασ_2.CH3+βσ_t.CH3+σ_i.G 此公式在作者以前的文章中己经报道。σ_i,G为稠苯芳基的某级效应。     

多晶Mn1-xCux(0.1≤x≤0.3)合金的磁诱发应变

采用X射线衍射分析、显微形貌观察、差示扫描量热法、标准电阻应变计法等实验方法,研究了室温下多晶Mn_1-xCu_x(0.1≤x≤0.3,原子分数)合金在低磁场中的磁诱发应变性能.结果表明,Mn_1-xCu_x合金经过长时间的固溶处理,在冷却过程中会出现fcc(γ)→fct(γ’)马氏体相变,形成(γ+γ 关键词： 磁诱发应变 MnCu合金 马氏体相变     

LaBaMnO薄膜的铁磁共振

用电子自旋共振实验研究La_0.65Ba_0.35MnO₃(LBMO)薄膜的磁性,从磁性膜的各向异性铁磁共振谱得到不同角度θ_h时的共振磁场B_r,求出样品的等效磁场B_eff及旅磁比γ,并通过样品的饱和磁化强度M_s,求出各向异性常数K.     

Dy3+掺杂Ge-Ga-S-CsI玻璃中红外发光特性研究

用熔融淬冷法制备了系列掺杂浓度的Dy³⁺:Ge-Ga-S-CsI硫卤玻璃样品,测试了样品拉曼光谱、折射率、吸收光谱、近红外及中红外荧光谱.应用Judd-Ofelt理论计算了Dy³⁺离子的强度参数 (Ω_i, i=2,4,6)、自发辐射跃迁概率(A)、荧光分支比(β)、以及辐射寿命(τ_rad)等光谱参数.研究了810 nm激光抽运下样品中红 关键词： 硫系玻璃 中红外发光 3+掺杂')" href="#">Dy³⁺掺杂 多声子弛豫     

稠苯芳杂环及其烷基质子化学位移的计算

本文提出了予测稠苯芳杂环及其烷基链上质子化学位移的计算方法。 将稠苯芳杂环化合物用凯库勒式表示,计算式为为需考虑的苯环内的乙烯基效应。σ_mi,ci为各苯环的环流效应。σ_1,Hc为各芳杂环的屏蔽效应,对杂环上质子它就是该单独芳杂环上相应质子的δ值,对苯环上质子要将它分解为各结构因素的效应,即:σ_1,He=(1/2)^d-1δ_x=y(或σ_z)+σ_c-c·σ_m,H. σ_x-y与σ_z为杂原子或其基团的屏蔽效应,σ_c=c为存在于芳杂环中的乙烯基的效应,σ_m,Hc为芳杂环的环流效应,d为对不同质子所考虑的键数。有取代基时需考虑取代基的效应。计算环上烷基质子的公式为:δ=σ_p,CH3+ασ_c,CH3+βσ_t,CH3+σ_l,G σ_l,G为稠苯芳杂环基的某级效应。     

General equation describing viscosity of metallic melts under horizontal magnetic field

Viscosities of pure Ga, Ga_(80)Ni_(20), and Ga_(80)Cr_(20) metallic melts under a horizontal magnetic field were investigated by a torsional oscillation viscometer. A mathematical physical model was established to quantitatively describe the viscosity of single and binary metallic melts under a horizontal magnetic field. The relationship between the viscosity and the electrical resistivity under the horizontal magnetic field was studied, which can be described as η_B = η +(2H/πΩ)B~2(η_B is the viscosity under the horizontal magnetic field, η is the viscosity without the magnetic field, H is the height of the sample,? is the electrical resistivity, and B is the intensity of magnetic field). The viscosity under the horizontal magnetic field is proportional to the square of the intensity of the magnetic field, which is in very good agreement with the experimental results. In addition, the proportionality coefficient of ηB and quadratic B, which is related to the electrical resistivity,conforms to the law established that increasing the temperature of the completely mixed melts is accompanied by an increase of the electrical resistivity. We can predict the viscosity of metallic melts under magnetic field by measuring the electrical resistivity based on our equation, and vice versa. This discovery is important for understanding condensed-matter physics under external magnetic field.     

利用非稳定子态容错实现密集旋转操作

Non-Clifford操作不能在量子纠错码上自然横向实现, 但可通过辅助量子态和在量子纠错码上能横向实现的Clifford操作来容错实现, 从而取得容错量子计算的通用性. 非平庸的单量子比特操作是Non-Clifford操作, 可以分解为绕z轴和绕x轴非平庸旋转操作的组合. 本文首先介绍了利用非稳定子态容错实现绕z轴和绕x轴旋转的操作, 进而设计线路利用魔幻态容错制备非稳定子态集, 最后讨论了运用制备的非稳定子态集模拟任意非平庸单量子比特操作的问题. 与之前工作相比, 制备非稳定子态的线路得到简化, 成功概率提高, 且在高精度模拟任意单量子比特操作时所消耗的非稳定子态数目减少了50%. 关键词： 容错量子计算 非稳定子态 魔幻态 Clifford操作     

Reduced s-d model with antiferromagnetically coupled impurity spins

An antiferromagnetic equivalent-neighbour Heisenberg interaction H_i between impurity spins is added to the reduced s-d Hamiltonian H_r previously introduced by simplifying the Kondo s-d exchange Hamiltonian H_K. Asymptotic mean-field theory is developed for H_r + H_i, in the presence and absence of external magnetic field, and applied to (La_1−xCe_x)Al₂ alloys. Specific heat c_i(T) and zero-field susceptibility χ_i(0,T) curves for (La_1−xCe_x)Al₂ are depicted. The coupling constants of H_r + H_i and conduction bandwidth are adjusted so that T_c temperatures for x = 0.2, 0.1 are equal to the experimental values. c_i(T) exhibits a jump at T_c and is decreasing for T < T_c. χ_i(0,T) has a first order pole at T_c which corresponds to the maximum of experimental susceptibility and χ_i(0,0) > 0. These results improve those obtained earlier on the grounds of H_r theory.     

A reduced hamiltonian model for U(∞) gauge theories

A reduced version of the Kogut-Susskind gauge theory is presented for U(∞) gauge theories. The reduced hamiltonian , where V_ij=trU_iD_iD_jD_j(U_iD_j) ⁺ (U_iD_j)⁺, is obtained by representing the group of space translations in the diagonal part of U(∞) U(∞). The space of states is invariant to the reduced gauge transformation U_i→ωU_iD_iω⁺D_i⁺ and the scalar product carries a gauge invariant constraint on U_i The hamiltonian is also expr essed in terms of the string variables of Bars. We present the linear potential between static quarks at strong coupling and sketch the weak coupling expansion.     

相位角对容性耦合电非对称放电特性的影响

电非对称效应作为一种新兴技术,被广泛用于对离子能量和离子通量的独立调控.此外,在改善等离子体的径向均匀性方面,电非对称效应也发挥了重要作用.本文采用二维流体力学模型,并耦合麦克斯韦方程组,系统地研究了容性耦合氢等离子体中当放电由多谐波叠加驱动时,不同谐波阶数k下的电非对称效应,重点观察了相位角θ_n对自偏压以及等离子体径向均匀性的影响.模拟结果表明：在同一谐波阶数下,自偏压随相位角θ_n的变化趋势不尽相同,且当k增大（k>3）时,自偏压随最高频相位角θ_k的变化范围逐渐减小.此外,通过调节相位角θ_n,可以改变轴向功率密度和径向功率密度的相对关系,进而实现对等离子体径向均匀性的调节.研究结果对于利用电非对称效应优化等离子体工艺过程具有一定的指导意义.     

Analysis of the Zeeman effect on D_α spectra on the EAST tokamak

Based on the passive spectroscopy,the D_α atomic emission spectra in the boundary region of the plasma have been measured by a high resolution optical spectroscopic multichannel analysis(OSMA) system in EAST tokamak.The Zeeman splitting of the D_α spectral lines has been observed.A fitting procedure by using a nonlinear least squares method was applied to fit and analyze all polarization π and ±σ components of the D_α atomic spectra to acquire the information of the local plasma.The spectral line shape was investigated according to emission spectra from different regions(e.g.,low-field side and high-field side) along the viewing chords.Each polarization component was fitted and classified into three energy categories(the cold,warm,and hot components) based on different atomic production processes,in consistent with the transition energy distribution by calculating the gradient of the D_α spectral profile.The emission position,magnetic field intensity,and flow velocity of a deuterium atom were also discussed in the context.     

“Missing moment” and perturbative methods for polynomial iterated function systems

An iterated function system (IFS) over a compact metric space X is defined by a set of contractive maps w_i: X → X, i = 1,…,N, with associated nonzero probabilities p_i > 0, p_i = 1. The “parallel” action of the maps defines a unique compact invariant attractor set A X which supports an invariant measure μ and which is balanced with respect to the p_i. For linear , the invariance of μ yields a relation between the moments g_n = ∫ χⁿ dμ which permits their recursive computation from the initial value g₀ = 1. For nonlinear w_i, however, the moment relations are incomplete and do not permit a recursive computation. This paper describes two methods of obtaining accurate estimates of the moments when the IFS maps w_i are polynomials: (i) application of the necessary Hausdorff conditions on the g_i to obtain convergent upper and lower bounds and (ii) a perturbation expansion approach. The methods are applied to some model problems.     

Measurement of L X-ray production cross sections and Li subshell fluorescence yields

L_i (i=1, 2 and 3) X-ray production cross sections have been measured for 14 elements in the atomic number range 55≤Z≤81 at 15.73 keV. The values of L_i subshell fluorescence yields (ω₁, ω₂ and ω₃) have been determined using the presently measured X-ray production cross sections and the theoretical L_i subshell photoionization cross sections values, Coster–Kronig transition probabilities and radiative emission rates. The measured X-ray production (XRP) cross-sections and fluorescence yield values were compared with the theoretical and semi empirical values, respectively.