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41.
42.
The results of paramagnetic measurements and EPR study on Gd(CoxNi1?x)2 compounds are presented. The data are discussed in the molecular field model. The reciprocal susceptibility follows a Néel-type variation. The thermal variation of gef values is analysed considering the Vangsness' relation for temperatures T >Tc. Finally, the EPR data are discussed in the correlation with those obtained from magnetic measurements. 相似文献
43.
A. Chevarier N. Chevarier A. Demeyer A. Alevra I.R. Lukas M.T. Magda M.E. Nistor 《Nuclear Physics A》1975,237(2):354-364
A study of the energy and angular distributions of protons emitted in 3He induced reactions was undertaken at an incident energy of 25.6 MeV. An analysis in the framework of the pre-equilibrium hybrid model did not succeed in explaining the overall behaviour of proton spectra; a contribution due to a break-up or a double stripping of the incident particle has to be taken into account. An attempt was made to account for these processes by performing a phase space calculation. This formulation was firstly tried in the case of deuteron induced reactions for which a break-up mechanism has already been confirmed in continuous proton spectra. The calculation extended to the case of 3He induced reactions showed that a double stripping mechanism could explain the observed distribution. 相似文献
44.
Magda Peligrad 《Probability Theory and Related Fields》1985,70(2):307-314
Summary In this note we estimate the rate of convergence in Marcinkiewicz-Zygmung strong law, for partial sumsS
n
of strong stationary mixing sequences of random variables. The results improve the corresponding ones obtained by Tze Leung
Lai (1977) and Christian Hipp (1979). 相似文献
45.
Magda M. Ayad S.E. Khayyal N.M. Farrag 《Spectrochimica Acta Part B: Atomic Spectroscopy》1985,40(9):1205-1209
A sensitive and rapid microdetermination method has been developed for the determination of cinchona alkaloids via their mercury complex. Different parameters of the procedure have been thoroughly studied. The percentage recoveries for quinine, quinidine, cinchonine and cinchonidine were found to be 98.97 ±0.62, 99.06 ± 0.62, 98.90 ± 0.74, respectively. The results obtained are favourably compared to the official ones. The method is characterised by its specificity, accuracy and good precision. 相似文献
46.
In the framework of the Multi-Channel Quantum Defect Theory (MQDT), a theoretical study of the dissociative excitation is
presented. Numerical results for the dissociative excitation cross sections of HD
+, D
2+, and DT
+ with electrons of energy between 2 and 12 eV are reported. The contribution of the vibrational continua of the two lowest
electronic states as explicit ionization channels has been considered. Within a quasi-diabatic representation of the molecular electronic states, the Born expansion of second order is done in the K-matrix evaluation. 相似文献
47.
Magda Rebelo 《Journal of Computational and Applied Mathematics》2010,234(9):2859-2869
This work is concerned with the numerical solution of a nonlinear weakly singular Volterra integral equation. Owing to the singular behavior of the solution near the origin, the global convergence order of product integration and collocation methods is not optimal. In order to recover the optimal orders a hybrid collocation method is used which combines a non-polynomial approximation on the first subinterval followed by piecewise polynomial collocation on a graded mesh. Some numerical examples are presented which illustrate the theoretical results and the performance of the method. A comparison is made with the standard graded collocation method. 相似文献
48.
We consider the almost sure asymptotic behavior of the periodogram of stationary and ergodic sequences. Under mild conditions we establish that the limsup of the periodogram properly normalized identifies almost surely the spectral density function associated with the stationary process. Results for a specified frequency are also given. Our results also lead to the law of the iterated logarithm for the real and imaginary parts of the discrete Fourier transform. The proofs rely on martingale approximations combined with results from harmonic analysis and techniques from ergodic theory. Several applications to linear processes and their functionals, iterated random functions, mixing structures and Markov chains are also presented. 相似文献
49.
Passive sampling is an attractive technique for the long‐term monitoring of pharmaceuticals in the water environment. The reliability of the received results depends on the properly performed calibration, namely the determination of analyte sampling rates. This step can be the source of a systematic error, as the sampling rate values are dependent on the water donor phase parameters. This is especially important for pharmaceuticals, since their chemical characteristics and ionic form change with pH. In this study, the cross‐effect of pH (3, 7, and 9) and salinity (0, 7, and 35 practical salinity unit, using artificial sea water) on the passive sampling of 21 pharmaceuticals (antiparasitics, beta‐blockers, non‐steroidal anti‐inflammatory drugs, sulfonamides) was tested. The primarily determined parameter was the sampling rate. In addition, the extraction efficiency, partitioning coefficient, and the concentration of the analytes on the sorbent were calculated. Generally, for the non‐steroidal anti‐inflammatory drugs, beta‐blockers, and antiparasitics, the change both in pH and salinity had a negligible impact on the mentioned experimental parameters. In contrast, the extraction of sulfonamides was impacted by both pH and salinity, while lipophilicity was not a decisive parameter. 相似文献
50.
Alessandro Allegri Valeriia Maslova Magda Blosi Anna Luisa Costa Simona Ortelli Francesco Basile Stefania Albonetti 《Molecules (Basel, Switzerland)》2020,25(22)
The photocatalytic oxidation of biomass-derived building blocks such as 5-hydroxymethylfurfural (HMF) is a promising reaction for obtaining valuable chemicals and the efficient long-term storage of solar radiation. In this work, we developed innovative TiO2-based materials capable of base-free HMF photo-oxidation in water using simulated solar irradiation. The materials were prepared by combining microemulsion and spray-freeze drying (SFD), resulting in highly porous systems with a large surface area. The effect of titania/silica composition and the presence of gold-copper alloy nanoparticles on the properties of materials as well as photocatalytic performance were evaluated. Among the lab-synthesized photocatalysts, Ti15Si85 SFD and Au3Cu1/Ti15Si85 SFD achieved the higher conversions, while the best selectivity was observed for Au3Cu1/Ti15Si85 SFD. The tests with radical scavengers for both TiO2-m and Au3Cu1/Ti15Si85 SFD suggested that primary species responsible for the selective photo-oxidation of HMF are photo-generated electrons and/or superoxide radicals. 相似文献