物理实验中测量结果及其不确定度的有效位数

本文主要介绍了物理实验中测量结果及其不确定度的有效位数,通过举例,对不同情况下与此相关的问题进行讨论,从而明确测量结果及其不确定度的有效位数的取舍.     

物理实验结果的不确定度及其修约规则

物理实验由于测量误差的存在,需要对实验测量结果进行评定,国际上通用的办法是计算测量结果的合成不确定度．本文结合物理实验的实际情况讨论了合成不确定度的计算方法,并对结果的修约规则给出了自己的建议．     

测量结果及其不确定度的修约方法

基于国家计量技术规范和实际应用情况,文章提出,为了保证修约值最接近原始数值、修约方法规范统一、易于操作,测量不确定度应统一取成两位有效位数,并据此来修约测量结果.     

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。     

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。     

物理实验数据处理中的一些问题的探讨

针对当前大学物理实验教学中关于数据处理的一些问题进行了探讨。提出了测量值与测量结果这两个词的不同。对于有效数字位数的保留进行了系统性的分析。指出了数据修约中所存在的一些不恰当之处。认为实验教学中宜考虑测量次数对实验结果的影响。简述了置信概率、概率型式、标准不确定度及扩展不确定度等问题的相互联系。     

快度间隔分析与逐事件快度关联

本文推导了逐事件快度间隔的起伏与逐事件快度关联的关系. 分析表明：快度间隔分析中新的和有意义的部分是推广的两粒子快度关联矩. 对于一些特殊的两粒子和矩阶数这些矩有明确的物理意义.     

基于FPGA的高精度时间间隔测量方法研究与实现

针对脉冲激光测距机的飞行时间间隔测量,介绍了基于FPGA实现高精度时间间隔测量的系统结构及关键技术。利用FPGA内嵌锁相环PLL可得到高速时钟的不同相位输出,可产生稳定的等间隔时间延迟,可实现对短时间间隔的量化测量,达到了优于纳米量级的测量精度。通过与数字插入法相结合,使系统的测量范围达到了200ns～43s。     

过原点直线拟合的斜率标准差与相关系数

分析了直线拟合中截距是否为零的两种不同条件与解法，讨论了两种相关系数表达式之间的关系，给出院截距为零时斜率标准差与相关系数的近似计算式。     

ICF靶场中光束口径与列阵间隔的研究

从靶场反射镜架模块的机械结构设计布局所需几何空间的角度出发,根据大口径、列阵器件的特殊要求,给出符合“神光III”装置总体技术要求的ICF靶场光束口径与列阵间隔之间的关系,得出靶场Δ纵、Δ横应满足的公式.     

Potential of chemical rounding for the performance enhancement of pyramid textured p-type emitters and bifacial n-PERT Si cells

We have investigated the effects of chemical rounding (CR) on the surface passivation and/or antireflection performance of AlO_x- and AlO_x/SiN_x:H stack-passivated pyramid textured p⁺-emitters with two different boron doping concentrations, and on the performance of bifacial n-PERT Si solar cells with a front pyramid textured p⁺-emitter. From experimental results, we found that chemical rounding markedly enhances the passivation performance of AlO_x layers on pyramid textured p⁺-emitters, and the level of performance enhancement strongly depends on boron doping concentration. Meanwhile, chemical rounding increases solar-weighted reflectance (R_SW) from ∼2.5 to ∼3.7% for the AlO_x/SiN_x:H stack-passivated pyramid textured p⁺-emitters after 200-sec chemical rounding. Consequently, compared to non-rounded bifacial n-PERT Si cells, the short circuit current density Jsc of 200-sec-rounded bifacial n-PERT Si cells with ∼60 and ∼100 Ω/sq p⁺-emitters is reduced by 0.8 and 0.6 mA/cm², respectively under front p⁺-emitter side illumination. However, the loss in the short circuit current density Jsc is fully offset by the increased fill factor FF by 0.8 and 1.5% for the 200-sec-rounded cells with ∼60 and ∼100 Ω/sq p⁺-emitters, respectively. In particular, the cell efficiency of the 200-sec-rounded cells with a ∼100 Ω/sq p⁺-emitter is enhanced as a result, compared to that of the non-rounded cells. Based on our results, it could be expected that the cell efficiency of bifacial n-PERT Si cells would be improved without additional complicated and costly processes if chemical rounding and boron doping processes can be properly optimized.     

相对压力系数实验直线拟合的结果分析

评价直线拟合质量宜用A类不确定度,拟合线段外推会使不确定度增大.     

Kernel-based regression of drift and diffusion coefficients of stochastic processes

To improve the estimation of drift and diffusion coefficients of stochastic processes in case of a limited amount of usable data due to e.g. non-stationarity of natural systems we suggest to use kernel-based instead of histogram-based regression. We propose a method for bandwidth selection and compare it to a widely used cross-validation method. Kernel-based regression reveals an enhanced ability to estimate drift and diffusion especially for a small amount of data. This allows one to improve resolvability of changes in complex dynamical systems as evidenced by an exemplary analysis of electroencephalographic data recorded from a human epileptic brain.     

Chirped Bragg光纤光栅的优化设计与优化指数

根据线性ChirpedBragg光纤光栅的一般原理 ,探讨了不同啁啾系数 ,准高斯耦合函数对Bragg反射光栅的反射率及色散补偿特性的响应。结果表明 :增大啁啾系数以及选取适当的准高斯耦合函数 ,在保证反射率较大的情况下 ,能有效地改善色散补偿特性。通过引入微波领域的“优化指数”这一概念 ,量化了色散补偿器的补偿能力。     

光谱辐射照度标准灯的数据插值与曲线拟合方法研究

介绍了多种插值方法与曲线拟合方法,对光谱辐射照度标准灯在所需波长间隔上的照度值进行内插运算,包括这些方法的模型建立、参数计算及误差分析过程。得到了效果较好的插值方法及分段普朗克曲线拟合模型,其中拟合模型较好地体现了光谱辐射照度标准灯的灯丝发射率及灯壳的光谱透射比。最终结果的相对偏差接近国家级计量院提供标准灯的最佳不确定度0.2%。     

Regression law and the renormalization of the transport coefficients

Using Mazur's lemma we show that the coarse-grained variables used in nonequilibrium statistical mechanics are the Onsager's regression variables. With this result we find a regression law for the fluctuations which is both non-Markovian and nonlinear. Considering the Markovian approximation and generalizing Onsager's ideas leading to the symmetry of the transport matrix, we formulate Mori and Fujisaka's method for the renormalization of transport coefficients due to nonlinear interactions.     

General regression neural network for prediction of sound absorption coefficients of sandwich structure nonwoven absorbers

In this paper, we propose a more general forecasting method to predict the sound absorption coefficients at six central frequencies and the average sound absorption coefficient of a sandwich structure nonwoven absorber. The kernel assumption of the proposed method is that the acoustics property of sandwich structure nonwoven absorber is determined by some easily measured structural parameters, such as thickness, area density, porosity, and pore size of each layer, if the type of the fiber used in nonwoven is given. By holding this assumption in mind, we will use general regression neural network (GRNN) as a prediction model to bridge the gap between the measured structural parameters of each absorber and its sound absorption coefficient. In experiment section, one hundred sandwich structure nonwoven absorbers are particularly designed with ten different types of meltblown polypropylene nonwoven materials and four types of hydroentangled E-glass fiber nonwoven materials firstly. Secondly, four structural parameters, i.e., thickness, area density, porosity, and pore size of each layer are instrumentally measured, which will be used as the inputs of GRNN. Thirdly, the sound absorption coefficients of each absorber are measured with SW477 impedance tube. The sound absorption coefficient at 125 Hz, 250 Hz, 500 Hz, 1000 Hz, 2000 Hz, 4000 Hz and their average value are used as the outputs of GRNN. Finally, the prediction framework will be carried out after the desired training set selection and spread parameter optimization of GRNN. The prediction results of 20 test samples show the prediction method proposed in this paper is reliable and efficient.     

Rapid evaluation for dielectronic recombination rate coefficients of Ni－like ions Gd and Ta

ＲａｐｉｄｅｖａｌｕａｔｉｏｎｆｏｒｄｉｅｌｅｃｔｒｏｎｉｃｒｅｃｏｍｂｉｎａｔｉｏｎｒａｔｅｃｏｅｆｆｉｃｉｅｎｔｓｏｆＮｉ－ｌｉｋｅｉｏｎｓＧｄａｎｄＴａ￥ＴＥＮＧＨｕａｇｕｏ；ＸＵＺｈｉｚｈａｎ；ＺＨＡＮＧＷｅｎｑｉ（ＣＣＡＳＴ（Ｗｏｒｌｄｌａ...     

利用WBEPM模型和稳定变分法计算氦原子的极化率和色散系数

以最弱受约束电子势模型(WBEPM)理论为基础,建立了计算氦原子多极动态极化率和相互作用色散系数的稳定变分方法.导出了该方法中所涉及的矩阵元和线性方程组的解析表达式.作为应用,具体计算了基态氦原子的极化率和两体色散系数,将计算结果与用其他方法所得到的结果进行了比较, 数据基本一致.     

利用WBEPM模型和稳定变分法计算氦原子的极化率和色散系数

以最弱受约束电子势模型(WBEPM)理论为基础,建立了计算氦原子多极动态极化率和相互作用色散系数的稳定变分方法 .导出了该方法中所涉及的矩阵元和线性方程组的解析表达式.作为应用,具体计算了基态氦原子的极化率和两体色散系数,将计算结果与用其他方法所得到的结果进行了比较,数据基本一致.