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81.
82.
Monatshefte für Mathematik - We regard the real symplectic group $$Sp(2n,{{\mathbb {R}}})$$ as a constraint submanifold of the $$2n\times 2n$$ real matrices $${\mathcal {M}}_{2n}({{\mathbb... 相似文献
83.
84.
Ciprian Preda Petre Preda Aurelian Craciunescu 《Journal of Mathematical Analysis and Applications》2012,385(1):572-581
We point out versions of a well-known theorem of R. Datko for nonuniform exponential contractions. More precisely, we obtain theorems that characterize the nonuniform exponential stability and the nonuniform exponential dichotomy for nonuniform exponential contractions. Thus, we generalize the results in Datko (1972) [8] and Preda and Megan (1985) [14]. 相似文献
85.
We develop a new version of a known theorem obtained by Van Minh, Räbiger, Schnaubelt in [N. Van Minh, F. Räbiger and R. Schnaubelt, Exponential stability, exponential expansiveness and exponential dichotomy of evolution equations on the half line, Integral Equ. Oper. Theory 32 (1998) pp. 332–353]. We rely completely on the classical ‘test functions’ method designed by Perron in 1930. The advantage of such a version is that is more readable since the classical method of Perron have been known for decades and that we do not involve a sophisticated mathematical machinery. Our approach is in contrast with the general philosophy of ‘autonomization’ the nonautonomous system, since we do not require to attach the evolution semigroup. Also we point out a discrete-time version of our approach extending some known results given by Li and Henry. 相似文献
86.
Hiromitsu Urakami Ali Gorkem Yilmaz Petre Osiceanu Yusuf Yagci Filipe Vilela Maria‐Magdalena Titirici 《Macromolecular rapid communications》2013,34(13):1080-1084
A simple and efficient polymer grafting onto hydrothermal carbonization (HTC)‐derived materials is described. The method pertains to the Diels–Alder cycloaddition reaction of furan moieties present on the surface of a HTC material with the maleimide groups stemming from a maleimide protected poly(ethylene glycol) (Me‐PEG‐MI) by a retro Diels‐Alder reaction. The precursor polymer, HTC material, and final product are characterized. Successful grafting is confirmed by elemental analysis, X‐ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and dispersion studies.
87.
A method was developed for assessing ascorbic acid concentration in fruit juices and wine by differential pulse voltammetry. The oxidation peak for ascorbic acid occurs at about 530 mV (versus SCE) on a Pt strip working electrode and at about 470 mV on a carbon paste working electrode. The influence of the operational parameters like the pulse amplitude and the pulse period on the analytical signal was investigated. The obtained calibration graph shows a linear dependence between the peak height and ascorbic acid concentration within the range 0.31-20 mM with a Pt working electrode, and within the range 0.07-20 mM with a carbon paste working electrode. The equation of the calibration graph was y = 21.839x + 35.726, r2 = 0.9940, when a Pt strip electrode was used (where y represents the value of the current intensity measured for the peak height, expressed as μA and x the analyte concentration, as mM). R.S.D. = 2.09%, n = 10, C(ascorbic acid) = 2.5 mM. The equation of the calibration graph was y = 3.4429x + 5.7334, r2 = 0.9971, when a carbon paste electrode was used (where y represents the value of intensity measured for the peak height, expressed as μA and x the analyte concentration, as mM). R.S.D. = 2.35%, n = 10, C(ascorbic acid) = 2.5 mM. The developed method was applied to ascorbic acid assessment in fruit juices and wine. The ascorbic acid content determined ranged between 6.83 mg/100 mL juice for soft drinks (Fanta Madness) and 54.74 mg/100 mL for citrus (lemon) juices obtained by squeezing fruit. Different ascorbic acid concentrations (from standard solutions) were added to the analysed samples, the degree of recovery being comprised between 94.74 and 104.97%. The results of ascorbic acid assessment by differential pulse voltammetry were compared with those obtained by cyclic voltammetry. The results obtained by the two methods were in good agreement. 相似文献
88.
Ciprian Preda Petre Preda Cristina Praţa 《Journal of Mathematical Analysis and Applications》2012,388(2):1090-1106
The aim of this paper is to study the connection between the (non)uniform exponential dichotomy of a non(uniform) exponentially bounded, strongly continuous evolution family and the admissibility of some function spaces. Thus, there are extended recent results established by L. Barreira and C. Valls (2010, 2011) in [10] and [11]. 相似文献
89.
90.
The almost Hamilton-Poisson realization, the stability problem, the existence of periodic solutions and the numerical integration via the Lie-Trotter integrator for the Clebsch system are discussed and some of their properties are pointed out. 相似文献