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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. 相似文献
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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. 相似文献
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《Current Applied Physics》2018,18(11):1268-1274
We have investigated the effects of chemical rounding (CR) on the surface passivation and/or antireflection performance of AlOx- and AlOx/SiNx: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 AlOx 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 (RSW) from ∼2.5 to ∼3.7% for the AlOx/SiNx: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. 相似文献
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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. 相似文献
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Chirped Bragg光纤光栅的优化设计与优化指数 总被引:1,自引:0,他引:1
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。 相似文献
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J. L. Del Rio 《Journal of statistical physics》1984,34(1-2):329-343
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. 相似文献
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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. 相似文献
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RapidevaluationfordielectronicrecombinationratecoefficientsofNi-likeionsGdandTa¥TENGHuaguo;XUZhizhan;ZHANGWenqi(CCAST(Worldla... 相似文献
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黄时中 《原子与分子物理学报》2016,33(6)
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. 相似文献
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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. 相似文献