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441.
Kazimierz Malanowski 《Mathematical Programming》1985,33(3):352-361
We consider a family of convex programming problems that depend on a vector parameter, characterizing those values of parameters at which solutions and associated Lagrange multipliers are Gâteaux differentiable.These results are specialized to the problem of the metric projection onto a convex set. At those points where the projection mapping is not differentiable the form of Clarke's generalized derivative of this mapping is derived. 相似文献
442.
提出了化学信号近似四阶导数计算的新方法——小波卷积法。该法通过信号与二阶样条小波函数的卷积运算对信号求导,能用于高噪音信号的直接求导,避免了普通导数运算将噪音放大的缺陷,即使对信噪比低至0.5的信号也能得到光滑的导数信号。详细讨论了尺度值、噪音、信号类型对求导的影响并建立了参数确定规则。将该法用于含噪音重叠分析化学信号的求导,能同时提高信号的分辨率和信噪比,结果满意。 相似文献
443.
HUANG Xu-ying XU Zhang-hua LIN Lu LIU Jian ZHONG Zhao-quan ZHOU Hua-kang 《光谱学与光谱分析》2018,38(12):3829-3838
旨在获取刚竹毒蛾危害下的毛竹叶片光谱特征波长,以助于该虫害的有效、准确识别。将于福建省顺昌县实测的105条高光谱数据随机划分为实验组(71条)和验证组(34条)。基于实验组数据,利用单因素方差分析获取健康、轻度危害、中度危害、重度危害等虫害等级间具有极显著差异的波长;结合常用遥感卫星的波段设置对上述波长进行筛选,采用欧式距离、相关系数及光谱角匹配等3种方法判定其虫害判别能力,获取特征波长,并引入验证组样本对其予以验证。结果表明:(1)受害叶片的光谱反射率明显低于健康叶片,虫害等级越高,其反射率越低;(2)受害叶片的光谱特征变化较大,随着虫害等级的上升,其光谱曲线中的“绿峰”及“红谷”趋于消失,“红边”斜率逐渐减小;(3)确定原始光谱703.43~898.56 nm及一阶微分光谱497.68~540.72,554.53~585.25和596.24~618.23 nm为刚竹毒蛾危害下的毛竹叶片光谱特征波长,其对该虫害具有较强的判别能力。该研究从叶片尺度剖析了寄主对刚竹毒蛾的响应机理,是“地-天”耦合的理论基础,可为虫害遥感监测技术体系的建立提供重要依据。 相似文献
444.
445.
In this paper, a family of fourth-order Steffensen-type two-step methods is constructed to make progress in including Ren-Wu-Bi’s methods [H. Ren, Q. Wu, W. Bi, A class of two-step Steffensen type methods with fourth-order convergence, Appl. Math. Comput. 209 (2009) 206-210] and Liu-Zheng-Zhao’s method [Z. Liu, Q. Zheng, P. Zhao, A variant of Steffensens method of fourth-order convergence and its applications, Appl. Math. Comput. 216 (2010) 1978-1983] as its special cases. Its error equation and asymptotic convergence constant are deduced. The family provides the opportunity to obtain derivative-free iterative methods varying in different rates and ranges of convergence. In the numerical examples, the family is not only compared with the related methods for solving nonlinear equations, but also applied in the solution of BVPs of nonlinear ODEs by the finite difference method and the multiple shooting method. 相似文献
446.
447.
We consider Darboux transformations for the derivative nonlinear Schrödinger equation. A new theorem for Darboux transformations of operators with no derivative term are presented and proved. The solution is expressed in quasideterminant forms. Additionally, the parabolic and soliton solutions of the derivative nonlinear Schrödinger equation are given as explicit examples. 相似文献
448.
W. TerouziM. De Luca A. BolliA. Oussama M. PatumiG. Ioele G. Ragno 《Vibrational Spectroscopy》2011,56(2):123-128
Four cultivars of olives picked up in the Moroccan region of Beni Mellal were subjected to a characterization and classification study. Analytical data were collected by Fourier transform infrared spectroscopy (FTIR), applied on the mesocarp of the fresh olives without any preliminary treatment. The spectral data were pre-treated by derivative elaboration based on the Savitzky-Golay algorithm to reduce noise and increase analytical information. Partial least squares discriminant analysis (PLS-DA) was performed to elaborate the measurement data and assess the discriminant features of the four cultivars. The PLS model was optimized by applying the Martens’ uncertainty test which provided to select the vibrational frequencies giving the most useful information. The optimized model resulted able to separate the four classes and classify new objects into the appropriate defined classes with a percentage prediction of 97%. The proposed method represents a real novelty to classify olives of different varieties by means of a rapid, inexpensive and reliable procedure. 相似文献
449.
Discontinuous Oblique Derivative Problem for Second Order Equations of Mixed Type in General Domains
《复变函数与椭圆型方程》2012,57(2):119-130
In [L. Bers (1958). Mathematical Aspects of Subsonic and Transonic Gas Dynamics . Wiley, New York; A.V. Bitsadze (1988). Some Classes of Partial Differential Equations . Gordon and Breach, New York; J.M. Rassias (1990). Lecture Notes on Mixed Type Partial Differential Equations. World Scientific, Singapore; H.S. Sun (1992). Tricomi problem for nonlinear equation of mixed type. Sci. in China ( Series A ), 35 , 14-20], the authors proposed and discussed the Tricomi problem of second order equations of mixed type in a special domain, and in [G.C. Wen (1998). Oblique derivative problems for linear mixed equations of second order. Sci. in China ( Series A ), 41 , 346-356], the author discussed the oblique derivative problem of second order equations of mixed type in a special domain. The present article deals with the discontinuous oblique derivative problem for quasilinear second order equations of mixed (elliptic-hyperbolic) type in general domains. Firstly, we give the formulation of the above boundary value problem, and then prove the existence of solutions for the above problem in general domains, in which the complex analytic method is used. 相似文献
450.
紫外一阶导数光度法测定壳聚糖的脱乙酰度 总被引:5,自引:0,他引:5
以盐酸为溶剂 ,N 乙酰基 D 葡萄糖胺为标准品 ,用紫外一阶导数光度法直接测定壳聚糖的脱乙酰度。标准曲线在 0 .0 0 2 5 0 .0 4 0 0mg·ml- 1范围内线性关系良好 ,回归方程dA/dλ =2 .349C + 0 .0 0 0 8(r =0 .9996 )。相对标准偏差为 0 .2 0 %~ 0 .76 % ,回收率为 99.8%~ 10 1.4 %。该法消除了共存物、浊度、色度的干扰 ,准确度高 ,重现性好 ,样品不需特殊处理简单易行 相似文献