高功率激光能量测试的卡计系数标定技术

提出在卡计系数标定中采用直线拟合方法,综合考察相关系数、斜率、截距、斜率和截距标准偏差等参数,以斜率相对标准偏差作为采用何种直线拟合的主要判断依据;若过零直线拟合的斜率相对标准偏差小于不过零的斜率相对标准偏差,认为截距为随机误差,卡计系数标定按照非等精度的加权平均法求解;反之,应按照不过零直线拟合,截距为测试的系统误差,根据定位回归误差大小判断并剔除粗大误差;这样可以合理给出激光能量测试的卡计标定系数。     

斜率与截距比的标准差估计的三种方法

斜率与截距比的标准差估计的三种方法朱鹤年（清华大学北京１０００８４）物理实验中运用直线拟合方法时被测量往往是斜率与截距之比，如电阻温度系数ａ’是直线方程Ｒ＝Ｒ０（１＋αＲｔ）中的斜率截距比，空气相对压力系数αｐ是方程ｐ＝ｐ０（１＋αｐｔ）的斜率截距比...     

读者来信

《大学物理》编辑部: 本刊第26卷第8期的《有效数字、误差分析与实验条件的选择》一文(以下简称原文),主要讨论了灵敏电流计内阻测定的问题.对于原文表2的数据,如套用模型,Ij=bnj a,直线拟合截距非零,9组数据所得截距a的相对不确定度tsa/a在0.74至19.8之间,平均值为3.62,说明可能更宜采用截距为零的新模型Ij=bnj.由新模型计算得出的斜率b及其标准差sb见下表,sb约为原模型结果之半.     

基于相邻子区相关系数的散斑质量评价方法

通过分析相邻子区间的相关系数与散斑质量的关系,提出一种新的全局散斑质量评价参数,即平均近邻零均值归一化互相关系数,可用于单个散斑的评价。与信息熵、平均灰度梯度这两种常用的全局散斑质量评价参数对比分析发现,提出的平均近邻零均值归一化互相关系数稳定性更好。实验结果表明,平均近邻零均值归一化互相关系数越大,位移测量中的均值误差和标准差越小,散斑的质量越高;当散斑在位移实验中的最大均值误差为0.01 pixel时,平均近邻零均值归一化互相关系数一直稳定在0.90左右,而其他几种参数值随着散斑尺寸的增大发生了较大的变化,证明了该参数的有效性,且更适合单个散斑的质量评价。     

氢原子光谱实验中里德堡常数的估计方法探讨

考察了氢原子光谱实验中估计里德堡常数的三种可能方法。我们的分析表明：由于标准差较大，且标准差不会随测量的谱线数趋于无穷而趋于零，采用所谓的斜率估计法是不太妥当的。虽然采用所谓截距估计法会使标准差大大减少，而且，标准差会随所测量的谱线数趋于无穷而趋于零。但RH的最佳估计值应该以波数为纵坐标y，（1／2^2—1／m^2）为横坐标x，作y=kx形式的拟合得到。     

下一代直线对撞机失谐结构尾场的精确计算：—盘荷波导电磁 …

利用变分法研究了周期性盘荷波导中零极模、二极模及更高极模式的电磁场特性。该方法考虑了栏片的圆弧，对真实结构没有做任何近似，是一种高精度方法，计算表明该方法的结果与实验测量值基本符合，与其它程序相比有很高的计算精度，这为下一步精确研究下一代直线对机失谐结构的尾场提供了一个很好的方法与工具。     

通过直线拟合的截距发现系统误差

通过对直线拟合中截距的分析发现系统误差.     

森林地表凋落物含水率红外光谱特性分析

为了实现森林地表凋落物含水率的实时测量，研究了森林地表凋落物含水率与红外光谱特性参数之间的关系。选取了四种森林地表凋落物，搭建了含水率红外光谱测量装置，获得了不同含水率所对应的红外吸收光谱图，分析了不同含水率与峰值吸收光强、谷肩连线与谷底连线交点纵坐标、吸收谷面积之间的关系。结果表明，含水率吸收谱线峰值在1 450 nm附近；三种光谱参数中，森林地表凋落物含水率与峰值吸收光强线性相关性最好，所得一元回归方程经F检验显著性良好，斜率的相对不确定度均小于1.0%和截距的相对不确定度小于0.51%，相关系数γ＞0.95。为含水率实时测量仪的光源选择和标定提供了依据。     

零净液流量两相流持液率与阻力特性研究

分别以牛顿流体和非牛顿流体为液相，研究了垂直管中零净液流量气液两相流的流动特性。提出了零净液流量气液两相流动模型，应用这一模型计算了零净液流量气液两相流的持液率和压力降，模型计算结果与试验结果相符。研究结果表明，零净液流量气液两相流与常规气液两相流相比具有特殊性，表现为其持液率仅由质量平衡方程控制，其摩擦阻力压力降为负值。     

浅海声场垂直振速与水平振速相关特性及应用

基于矢量水听器记录的质点振速信号,研究了浅海声场垂直振速与水平振速的相关特性,理论与仿真结果表明记录的垂直振速与水平振速的相关系数是矢量水听器俯仰角度的函数,矢量水听器不发生俯仰时二者的相关系数约为零.基于上述特点,提出了一种利用矢量水听器记录信号自适应校正矢量水听器俯仰姿态的方法,实验结果表明,该方法能有效校正矢量水听器俯仰姿态.     

Reggeon quantum mechanics: Effect of four-reggeon couplings

We study reggeon quantum mechanics when four-reggeon couplings are present as well as the conventional three-reggeon coupling. We show that as the reggeon intercept is increased an infinite number of states pass through energy zero. We give the values of the intercepts at which states pass through zero, construct the states explicitly, and tell how fast their energy changes with intercept. We show that these higher states do not interfere with the construction of spin models. However, no spin model is possible if the one-reggeon ? three-reggeon coupling is non-zero.     

Two-particle correlations from the q-Boson viewpoint

We propose and develop to some extent a novel approach, which allows to effectively describe, for relativistic heavy-ion collisions, the empirically observed deviation from unity of the intercept λ (i.e. the measured value corresponding to zero relative momentum p of two registered identical pions or kaons) of the two-particle correlation function C(p,K). The approach is based on the use of two versions of the so-called q-deformed oscillators and the corresponding picture of ideal gases of q-bosons. By these techniques the intercept λ is put into direct correspondence with the deformation parameter q. For fixed deformation strength, the model predicts particular dependence of the intercept λ on the pion pair mean momentum K. Received: 2 July 1999 / Revised version: 11 November 1999     

加性信号调制下指数形式关联噪声驱动的单模激光的光强关联时间

采用线性化近似,计算了加性信号调制下的由具有指数关联的两白噪声驱动的单模激光增益模型的光强关联时间.发现两噪声间关联程度对光强关联时间随噪声强度的变化曲线有很大的影响,两噪声间关联程度取不同值时,光强关联时间随噪声强度的变化曲线中将出现极大值(即出现共振) 或极小值(即出现抑制) .     

Correlation of fluctuations of the quadrature amplitudes of interacting modes in the instability region of intracavity third-harmonic generation

Correlation of fluctuations of quadrature amplitudes of interacting modes is studied for the process of intracavity third-harmonic generation in the region of instability. It is shown that this correlation strongly depends on the value of the nonlinear mode coupling coefficient. For small values of the coupling coefficient, correlation of fluctuations of quadrature amplitudes is small. With increasing coupling coefficient, the correlation increases (states of the subsystems become entangled). Then, starting from a certain value of the coupling coefficient, it starts decreasing gradually, tending to zero (entanglement of states of the subsystems decreases). Correlation of fluctuations of quadrature amplitudes decreases also when the amplitude of the fundamental mode perturbing field is decreased.     

近地面大气光学湍流空间相关特性的实验研究

本文提出了基于光纤湍流传感器阵列的大气光学湍流空间相关函数测量原理, 并确定了具体的测量方案和数据统计方法. 利用光纤湍流传感器阵列在近地面开展了大气光学湍流空间相关特性的实验测量研究, 尽可能全面地展示光学湍流空间相关函数的各种形式. 结果表明, 大气光学湍流的一维空间相关函数主要表现为两种结构形态, 其一, 58.7%基本符合各向同性湍流空间相关函数模型, 其相关函数在一定尺度范围内呈现随尺度的增大而减小的趋势, 当超过该尺度时, 相关系数接近于0; 其二, 另有37.9%表现为与尺度无关, 相关系数维持在0附近小幅度随机振荡. 不难发现:光学湍流的空间相关特性主要取决于湍流的强弱和湍流是否得以充分发展, 同时, 湍流的相干结构将引起空间相关函数的小幅度振荡. 以空间布点探测直接获取光学湍流空间相关函数的方法, 不仅为分析湍流空间结构奠定了实验基础, 同时, 也为进一步建立非K湍流模型提供了理论开端.     

Quantum dynamics of interacting modes in the process of intracavity subharmonic generation

The dynamics of correlation between fluctuations of the number of photons of interacting modes is investigated for the process of intracavity subharmonic generation. It is demonstrated that this correlation strongly depends on the nonlinear mode coupling coefficient. For small values of the coupling coefficient, the correlation between fluctuations of the number of photons is small. With an increase in the coupling coefficient, the correlation increases (the state of subsystems becomes entangled) and, starting from a particular value of the coupling coefficient, starts to decrease with further increase in the coupling coefficient, gradually approaching zero (entanglement of subsystem states decreases). The quantum dynamics of the number of photons, quantum entropy, and Wigner function of the stationary state of the fundamental and subharmonic modes is investigated. It is demonstrated that the dynamics of these quantities also strongly depends on the coupling coefficient of the interacting modes. We show that, for large values of the mode coupling coefficient and long interaction times, the subharmonic mode becomes localized in a two-component state with equal probabilities of finding it in each component. Quantum entropy of this state is smaller than maximum entropy of the two-component state equal to ln2, which suggests that quantum-mechanical interference takes place between the subharmonic mode components.     

Cross-correlation coefficient of field emission flicker noise from potassium submonolayers on tungsten

In a field emission tube with two probe-holes the cross-correlation coefficient of current fluctuations from potassium submonolayers on tungsten has been measured. The cross-correlation coefficient depends on the probe-hole positions, i.e. on the substrate structure, and increases with emitter temperature and with potassium coverage; it is zero at the minimum of the noise power accompanying the work function minimum. These measurements seem to show for the first time the existence of spatial correlation in adsorbate submonolayers.     

On the self-consistent Pomeron pole

A model is considered in which a Pomeron is regarded as a self-consistent intercept one Regge pole resulting from a Bethe-Salpeter-like equation in Reggeon theory. The absorptive nature of a two Pomeron cut is crucial for realization of self-consistency. For zero mass Pomerons the model predicts the vanishing of the triple Pomeron coupling and softening of Pomeron cut contributions to inclusive reactions in triple and di-triple Regge regions.