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101.
Fractional wavelet transform (FWT) was applied to the original absorption spectra of lacidipine (LAC) and its photodegradation product (LACD), and the resulting FWT spectra were processed by continuous wavelet transform (CWT) and multilinear regression calibration (MLRC) for the simultaneous quantitative analysis of both products in their binary mixtures. These methods do not require any chemical separation step and chemical complex reaction to obtain a detectable signal for the degradation product. By using the Mexican hat function, 2 calibration functions for LAC and LACD were obtained by measuring the CWT transformed signals at 416.1 nm for LAC and 414.6 nm for LACD, after FWT processing of the original absorption spectra. The calibration graphs were linear in the concentration range of 5.08-40.64 microg/mL for LAC and 0.51-8.16 microg/mL for LACD. The limit of detection and the limit of quantitation were found to be 0.289 and 0.956 microg/mL for LAC and 0.036 and 0.118 microg/mL for LACD, respectively. For comparison, the MLRC algorithm was applied to the linear regression functions for the individual drug and its photoproduct. In this approach, a set of linear regression functions was obtained from the relationship between concentrations and FWT signals in the wavelength range 411.0-412.4 nm. Both methods were applied to the quantitative evaluation of LAC and LACD in laboratory and pharmaceutical samples, and produced very satisfactory results. 相似文献
102.
Trihalomethanes (THMs), chlorinated by-products in drinking water, have been determined by comparing some analytical methods, based on the following techniques: liquid-liquid extraction-gas chromatography-mass spectrometry (LLE-GC-MS), headspace-gas chromatography-mass spectrometry (headspace-GC-MS) and purge and trap-gas chromatography-mass spectrometry (PT-GC-MS). The mass spectrometer was operated in the SIM mode. The quantitative methods were validated and compared to the ability to identify and to measure reliably the yields of the toxic compounds. Good validation parameters were obtained for each method. 相似文献
103.
Dumitru Popa 《Journal of Mathematical Analysis and Applications》2010,370(2):415-430
Various concepts of multilinear summing operators were introduced in the last years, by extending the well-known one from the linear case. In this paper, we prove that, as in the linear case, there is a splitting theorem for dominated operators. As a consequence of this result, we prove various multilinear variants of Pietsch's composition theorem. 相似文献
104.
Dumitru Motreanu Viorica V. Motreanu Nikolaos S. Papageorgiou 《Monatshefte für Mathematik》2010,159(1-2):59-80
First we prove the existence of a nontrivial smooth solution for a p-Laplacian equation with a (p ? 1)-linear nonlinearity and a noncoercive Euler functional, under hypotheses including resonant problems with respect to the principal eigenvalue of ${(-{\it \Delta}_p,\,W^{1,p}_0(Z))}$ . Then, for the semilinear problem (i.e., p = 2), assuming nonuniform nonresonance at infinity and zero, we prove a multiplicity theorem which provides the existence of at least three nontrivial solutions, two being of opposite constant sign. Our approach combines minimax techniques with Morse theory and truncation arguments. 相似文献
105.
Nguyen Huy Tuan Le Nhat Huynh Dumitru Baleanu Nguyen Huu Can 《Mathematical Methods in the Applied Sciences》2020,43(6):2858-2882
In this paper, we consider an inverse problem of recovering the initial value for a generalization of time-fractional diffusion equation, where the time derivative is replaced by a regularized hyper-Bessel operator. First, we investigate the existence and regularity of our terminal value problem. Then we show that the backward problem is ill-posed, and we propose a regularizing scheme using a fractional Tikhonov regularization method. We also present error estimates between the regularized solution and the exact solution using two parameter choice rules. 相似文献
106.
Ngoc Tran Bao Dumitru Baleanu Duc Le Thi Minh Tuan Nguyen Huy 《Mathematical Methods in the Applied Sciences》2020,43(12):7208-7226
This paper studies partial differential equation model with the new general fractional derivatives involving the kernels of the extended Mittag–Leffler type functions. An initial boundary value problem for the anomalous diffusion of fractional order is analyzed and considered. The fractional derivative with Mittag–Leffler kernel or also called Atangana and Baleanu fractional derivative in time is taken in the Caputo sense. We obtain results on the existence, uniqueness, and regularity of the solution. 相似文献
107.
The concept of a deductive system has been intensively studied in algebraic logic, per se and in connection with various types
of filters. In this paper we introduce an axiomatization which shows how several resembling theorems that had been separately
proved for various algebras of logic can be given unique proofs within this axiomatic framework. We thus recapture theorems
already known in the literature, as well as new ones. As a by-product we introduce the class of pre-BCK algebras. 相似文献
108.
109.
Dumitru Popa 《Quaestiones Mathematicae》2018,41(5):683-692
We prove two characterizations of new Cohen summing bilinear operators. The first one is: Let X, Y and Z be Banach spaces, 1 < p < ∞, V : X × Y → Z a bounded linear operator and n ≥ 2 a natural number. Then V is new Cohen p-summing if and only if for all Banach spaces X1,?…?, Xn and all p-summing operators U : X1 × · · · × Xn → X, the operator V ? (U, IY) : X1 × · · · × Xn × Y → Z is -summing. The second result is: Let H be a Hilbert space,, Y, Z Banach spaces and V : H × Y → Z a bounded bilinear operator and 1 < p < ∞. Then V is new Cohen p-summing if and only if for all Banach spaces E and all p-summing operators U : E → H, the operator V ? (U, IY) is (p, p*)-dominated. 相似文献
110.