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21.
We studied the photolysis of neat protonated and heavy water using pump-probe and pump-repump-probe spectroscopy. A novel recombination channel is reported leading to ultrafast quenching (0.7 ± 0.1 ps) of almost one third of the initial number of photo-generated electrons. The efficiency and the recombination rate of this channel are lower in heavy water, 27 ± 5% and (0.9 ± 0.1 ps)(-1), respectively. Comparison with similar data measured after photodetachment of aqueous hydroxide provides evidence for the formation of short-lived OH:e(-) (OD:e(-)) pairs after indirect photoionization of water at 9.2 eV. 相似文献
22.
Konakchiev A Todorova M Mikhova B Vitkova A Najdenski H 《Natural product communications》2011,6(6):905-906
The essential oil of Achillea distans W. et K. flower heads was analyzed by GC and GC-MS. Altogether 43 components in concentrations more than 0.1% were identified representing 93.5% of the oil composition. The main constituents were 1,8-cineole (16.8%), trans-thujone (9.8%), sabinene (8.2%), borneol (7.5%), beta-pinene (6.5%), and camphor (5.8%). The oil showed moderate activity against Staphylococcus aureus and Candida albicans, and weak activity against Salmonella typhimurium, Proteus vulgaris, and Escherichia coli. 相似文献
23.
Abstract Vibrational spectra of 2,2′-pyridil and 2,2′-pyridil-18O in the solid state and in solutions have been measured in the Raman (4000–50 cm?1) and infrared (4000–100 cm?1). The assignment of the bands observed is performed using the group vibrational concept and isotopic shifts data of the normal modes. The presence of synand anti-phase vibrations of both pyridyl rings is discussed. The results are compared to the corresponding data for some similar molecules. 相似文献
24.
V. M. Abazov M. Milanov D. Kolev N. Nenoff B. Todorov 《Zeitschrift für Physik A Hadrons and Nuclei》1980,295(1):65-72
The energy and angular distributions ofp, d, t,3He and4He from the three targets Cu, Ag and Au were measured at five different angles for bremsstrahlung with peak energy 500MeV. The measurements were made using a telescope consisting of four surface-barrier detectors. The experimental data are compared with cascade-evaporation calculations. For the4He-distributions the calculations were extended to include the contribution from knock-out of surface alphas by the cascade nucleons. The comparison shows that the main contribution comes from evaporation but that there is a direct component of the order of 10%. 相似文献
25.
Thin films of Sb, Se and Sb2Se3 are deposited onto glass and irradiated by a cw-Ar+ laser beam. The kinetics of crystallization and oxidation are traced via the time dependence of optical reflectivity and temperature, T, of the irradiated zone. For Sb2Se3, transformations start abruptly when T attains a critical value, T
c, independently of the laser beam power. These T
c values are comparable to the ones observed under furnace annealing conditions. 相似文献
26.
James H. Bramble Tzanio V. Kolev Joseph E. Pasciak. 《Mathematics of Computation》2005,74(252):1575-1598
In this paper we consider an approximation to the Maxwell's eigenvalue problem based on a very weak formulation of two div-curl systems with complementary boundary conditions. We formulate each of these div-curl systems as a general variational problem with different test and trial spaces, i.e., the solution space is and components in the test spaces are in subspaces of , the Sobolev space of order one on the computational domain . A finite-element least-squares approximation to these variational problems is used as a basis for the approximation. Using the structure of the continuous eigenvalue problem, a discrete approximation to the eigenvalues is set up involving only the approximation to either of the div-curl systems. We give some theorems that guarantee the convergence of the eigenvalues to those of the continuous problem without the occurrence of spurious values. Finally, some results of numerical experiments are given.
27.
In this paper, we present a cubically convergent method for finding the largest eigenvalue of a nonnegative irreducible tensor. A cubically convergent method is used to solve an equivalent system of nonlinear equations which is transformed by the tensor eigenvalue problem. Due to particular structure of tensor, Chebyshev’s direction is added to the method with a few extra computation. Two rules are designed such that the descendant property of the search directions is ensured. The global convergence is proved by using the line search technique. Numerical results indicate that the proposed method is competitive and efficient on some test problems. 相似文献
28.
29.
M. Kolev S. Nawrocki B. Zubik-Kowal 《Communications in Nonlinear Science & Numerical Simulation》2013,18(6):1473-1480
We investigate a new mathematical model that describes lung cancer regression in patients treated by chemotherapy and radiotherapy. The model is composed of nonlinear integro-differential equations derived from the so-called kinetic theory for active particles and a new sink function is investigated according to clinical data from carcinoma planoepitheliale. The model equations are solved numerically and the data are utilized in order to find their unknown parameters. The results of the numerical experiments show a good correlation between the predicted and clinical data and illustrate that the mathematical model has potential to describe lung cancer regression. 相似文献