Effect of a Localized Random Forcing Term on the Korteweg-De Vries Equation

In this work, we numerically investigate the influence of a white noise-type forcing on the phenomenon of forced generation of solitons by a localized moving disturbance. Our numerical method is based on finite elements and least-squares. We present numerical experiments for different values of noise amplitude and Froude number, which describe some damping effects on the emission of solitons.     

Perturbation of systems of linear algebraic equations

A classical perturbation result for nonsingular systems of linear algebraic equations is extended to general consistent systems under any norm. An optimal perturbation result is also obtained for general linear least squares problems under a Euclidean norm.     

A Levenberg–Marquardt method based on Sobolev gradients

We extend the theory of Sobolev gradients to include variable metric methods, such as Newton’s method and the Levenberg–Marquardt method, as gradient descent iterations associated with stepwise variable inner products. In particular, we obtain existence, uniqueness, and asymptotic convergence results for a gradient flow based on a variable inner product.     

相对误差最小二乘法的TDLAS气体浓度标定曲线拟合

可调谐半导体激光光谱技术(TDLAS)是光谱检测技术的一个分支,具有高灵敏度、高分辨率、实时监测、便携性好、小型化等优点,在工业环保、医疗检测、气象监测等领域得到了广泛应用.TDLAS气体传感器的测量精度与标定曲线密切相关,标定时,常用最小二乘法对标定曲线进行多项式拟合,但最小二乘法是以绝对误差的最小平方和作为评价标准...     

Fabrication of in situ alkali doped flexible CIGSSe solar cells by using aqueous spray deposition

Flexible Cu(In,Ga)(S,Se)₂ (CIGSSe) solar cells were fabricated on stainless steel foil by using aqueous spray deposition method. Since stainless steel foil is used, external alkali doping is necessary to passivate defects in CIGSSe absorber. We investigated effects of (Na, K) co-doping and selenization temperature on solar cell performance. With co-doping of Na and K, defect states were passivated significantly and highest power conversion efficiency (PCE) was obtained. However, at higher K concentration of more than 0.5%, different growth mode of CIGSSe was observed and deep defect states were developed, decreasing PCE. In addition, selenization temperature effects were studied by varying selenization temperatures. With higher selenization temperature, defect passivation for the CIGSSe absorber was more apparent, which facilitated increase of open circuit voltage. However, short circuit current was observed to be decreased at higher selenization temperature of 570 °C. This work demonstrates in-situ alkali co-doping into CIGSSe absorber with simple and low-cost spray deposition in an air environment.     

平面问题中悬臂梁固支边界条件的简化方法

弹性力学在处理梁的固支边界条件时,基于应变分量积分得到的位移表达式通常比较复杂,无法精确满足固支边界条件,因而只能求得近似解。本文采用固支边界中点的位移约束,结合最小二乘法重新定义了固支边界条件,实现了对梁的位移的准确求解。比较不同边界条件提法的差异,将有助于学生灵活掌握边界条件的简化方法,为开展研究性教学提供素材。

     

Approximation to the distribution of the least squares estimators in two dimensional cosine models by randomly weighted bootstrap

Recently, Kundu and Gupta （Metrika, 48：83 C 97, 1998） established the asymptotic normality of the least squares estimators in the two dimensional cosine model. In this paper, we give the approximation to the general least squares estimators by using random weights which is called the Bayesian bootstrap or the random weighting method by Rubin （Annals of Statistics, 9：130 C 134, 1981） and Zheng （Acta Math. Appl. Sinica （in Chinese）, 10（2）： 247 C 253, 1987）. A simulation study shows that this approximation works very well.     

自支撑柔性聚(5-吲哚硼酸)膜的电化学合成及表征

在三氟化硼乙醚/乙腈的混合体系中,5-吲哚硼酸的电化学氧化可以获得导电率为9×10-4 S·cm-1的自支撑柔性聚(5-吲哚硼酸)膜.5-吲哚硼酸在80％的三氟化硼乙醚亿腈溶液中的起始氧化电位约为0.80V红外光谱确定了5-吲哚硼酸的聚合位点在C2和C3位上.紫外可见光谱测试结果表明聚(5-吲哚硼酸)的能隙约为2.48...     

An LP-based proof for the non-existence of a pair of orthogonal Latin squares of order 6

This paper presents an alternative proof for the non-existence of orthogonal Latin squares of order 6. Our method is algebraic, rather than enumerative, and applies linear programming in order to obtain appropriate dual vectors. The proof is achievable only after extending previously known results for symmetry elimination.     

Real-time restoration of rotational blurred image using gradient-loading

The key to the restoration of rotational motion blurred image is how to restore the image under a low cost and to correct the irreversibility of the degradation function matrix.Based on the special qualities of degradation function matrix and precise deduction in space-domain, we present a new approach using gradient-loading for restoration of rotational blurred image.By easily adding a gradient operator, the irreversibility of the original matrix is corrected and can be applied for inverse filtering then.Gradientloading is the optimized approach which combines the advantages of both the approaches using constrained least square filtering and traditional diagonal-loading.Compared with the approach using least square filtering, its peak signal-to-noise ratio (PSNR) is improved from 3.18 to 6.46dB, while the computing time is reduced to 1/2-1/3.Experimental results demonstrate the effectiveness, noise-resistibility, robustness, and low complexity of this approach, which make it more suitable for real-time environment.