Extremal interpolation with minimal norm of the second derivative in the space [IMG align=ABSMIDDLE alt=$ L_p(\mathbb R)$]tex_im_3103_img1[/IMG]

2022 ◽  
Vol 86 (1) ◽  
Author(s):  
Valerii Trifonovich Shevaldin
1994 ◽  
Vol 86 (2) ◽  
pp. 349-354 ◽  
Author(s):  
Haiping Su ◽  
Michel D. Ransom ◽  
Edward T. Kanemasu ◽  
Tanvir H. Demetriades‐Shah

2017 ◽  
Vol 919 (1) ◽  
pp. 7-12
Author(s):  
N.A Sorokin

The method of the geopotential parameters determination with the use of the gradiometry data is considered. The second derivative of the gravitational potential in the correction equation on the rectangular coordinates x, y, z is used as a measured variable. For the calculated value of the measured quantity required for the formation of a free member of the correction equation, the the Cunningham polynomials were used. We give algorithms for computing the second derivatives of the Cunningham polynomials on rectangular coordinates x, y, z, which allow to calculate the second derivatives of the geopotential at the rectangular coordinates x, y, z.Then we convert derivatives obtained from the Cartesian coordinate system in the coordinate system of the gradiometer, which allow to calculate the free term of the correction equation. Afterwards the correction equation coefficients are calculated by differentiating the formula for calculating the second derivative of the gravitational potential on the rectangular coordinates x, y, z. The result is a coefficient matrix of the correction equations and corrections vector of the free members of equations for each component of the tensor of the geopotential. As the number of conditional equations is much more than the number of the specified parameters, we go to the drawing up of the system of normal equations, from which solutions we determine the required corrections to the harmonic coefficients.


Mathematics ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 1398
Author(s):  
Natalia Kolkovska ◽  
Milena Dimova ◽  
Nikolai Kutev

We consider the orbital stability of solitary waves to the double dispersion equation utt−uxx+h1uxxxx−h2uttxx+f(u)xx=0,h1>0,h2>0 with combined power-type nonlinearity f(u)=a|u|pu+b|u|2pu,p>0,a∈R,b∈R,b≠0. The stability of solitary waves with velocity c, c2<1 is proved by means of the Grillakis, Shatah, and Strauss abstract theory and the convexity of the function d(c), related to some conservation laws. We derive explicit analytical formulas for the function d(c) and its second derivative for quadratic-cubic nonlinearity f(u)=au2+bu3 and parameters b>0, c2∈0,min1,h1h2. As a consequence, the orbital stability of solitary waves is analyzed depending on the parameters of the problem. Well-known results are generalized in the case of a single cubic nonlinearity f(u)=bu3.


RSC Advances ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 3834-3842
Author(s):  
Khalid A. M. Attia ◽  
Ahmad A. Mohamad ◽  
Mohamed S. Emara ◽  
Ahmed M. Abdel-Raoof ◽  
Mohamed A. Hasan ◽  
...  

In this work, the quantitative determination of an erectile dysfunctional drug avanafil in the presence of its acid-induced degradation product was achieved via the application of a pre-optimized novel spectrofluorimetric method.


1985 ◽  
Vol 31 (2) ◽  
pp. 279-281 ◽  
Author(s):  
J Parks ◽  
H G Worth

Abstract In this procedure hemoglobin is converted to its reduced form and the magnitude of the zero-order spectral shift of the reduced hemoglobin peak at 430 nm to the carboxyhemoglobin peak at 418 nm is determined by second-derivative spectrum analysis. The method is simple, straightforward to set up, and rapid. A result may be obtained within 15 min of receiving the sample. It is sufficiently sensitive to differentiate carboxyhemoglobin concentration in the blood of smokers and nonsmokers.


BioTechniques ◽  
2005 ◽  
Vol 38 (2) ◽  
pp. 287-293 ◽  
Author(s):  
Van Luu-The ◽  
Nathalie Paquet ◽  
Ezequiel Calvo ◽  
Jean Cumps

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