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1.
Aleksandra S.Kosti 《Algebra Colloquium》2021,28(4):625-634
Let R be an associative unital ring and not necessarily commutative.We analyze conditions under which every n × n matrix A over R is expressible as a sum A =E1 +…+ Es + N of (commuting) idempotent matrices Ei and a nilpotent matrix N. 相似文献
2.
In this paper, based on the Hermitian and skew-Hermitian splitting, we give a generalized modified Hermitian and skew-Hermitian splitting (GMHSS) method to solve singular complex symmetric linear systems, this method has two parameters. We give the semi-convergent conditions, and some numerical experiments are given to illustrate the efficiency of this method. 相似文献
3.
Steva Lević Nina Obradović Vladimir Pavlović Bojana Isailović Ivana Kostić Miodrag Mitrić Branko Bugarski Viktor Nedović 《Journal of Thermal Analysis and Calorimetry》2014,118(2):661-668
In this study, polyvinyl alcohol (PVA) nanofibers with ethyl vanillin as an active compound were prepared using electrospinning technique. The final products of electrospinning process were in the form of nanofibers films. PVA/ethyl vanillin nanofibers, having fibers diameters in the range 100–1700 nm, were successfully electrospun from ethanol/water mixture of PVA and ethyl vanillin. The effects of immobilization process on ethyl vanillin thermal properties were investigated by differential scanning calorimetry (DSC). The results of DSC showed significant influence of immobilization process on thermal properties of ethyl vanillin. It was noticed that melting point of immobilized ethyl vanillin was lower (~55 °C) compared to free flavor (~77 °C). Our results showed that films based on PVA/ethyl vanillin nanofibers are mechanically stable. 相似文献
4.
Jančić-Stojanović B Rakić T Kostić N Vemić A Malenović A Ivanović D Medenica M 《Talanta》2011,85(3):1453-1460
In this paper a new chromatographic response function (CRF) is designed and proposed for utilization in the optimization strategies. The function capability to represent the overall quality of a experimentally obtained chromatograms was compared to the other two objective functions and proved to give more accurate and reliable results. The new CRF has improved concept of separation and time term estimation. It reflects all important defects of the chromatogram such as the appearance of asymmetrical or overlapping peaks and prolonged elution time and allows the appropriate weighting of each of them. The LC separation of raloxifene and its four impurities was evaluated through the central composite design experimental plan choosing the new CRF to be the only output of the system. The function demonstrated the ability to judge the impact of the complex interactions of the selected chromatographic parameters (acetonitrile content in the mobile phase, sodium dodecyl sulfate concentration in the water phase, pH of the mobile phase and column temperature) on the mixture behavior and led to the determination of the optimal separation conditions. The newly developed CRF proved to have the advanced performances and it presents the important step forward in the optimization of the chromatographic separation. 相似文献
5.
We have found the equation of the etch pit wall in solid state nuclear track detectors, as follows: where: x is the distance along a track from the point where the particle entered the detector; V(x) is the ratio of the track etch rate to the bulk etch rate; C is the integration constant that can be determined from particle penetration depth, and y is the normal distance from the particle trajectory to the etch pit wall. The equation is derived assuming the increasing track etch rate Vt along the particle trajectory.
The above equation can be used for the simulation of the track growth and calculating the major and the minor axis of the etch pit opening. The corresponding computer program was set up. The input parameters of this program are: alpha particle energy, incidence angle and removed layer: the output are track parameters. The results obtained by this method are compared with another approach given by Somogyi and Szalay (1973) and reasonably good agreement is found. 相似文献
6.
We report Xα SW MO calculations on (η2-C4H4)Fe(CO)3 and its five transition states, formed by removing a half of an electron from each of the five uppermost filled MOs. Eigenvalues in the transition states depend only slightly upon the MO from which the “high-ionization” occurs. The MOs are more polarized in the transition states than in the ground state. The C4H4-Fe bonding is highly covalent. 相似文献
7.
Lj. Cvetkovi? V. Kosti? 《Applied mathematics and computation》2012,218(9):4798-4805
The recent application of the diagonal dominance in the development of the optimization algorithms in the wireless sensor networks design, has been done by Yuan and Yu (2006) [14], extended in Yu et al. (2006) [9], and surveyed in Machado and Tekinay [11]. In this paper, we will use the concept of generalized diagonal dominance, to improve the obtained results regarding the power control game, in three directions. We also discuss the applicability of such improvements. 相似文献
8.
Time-like orbits in Schwarzschild space-time are presented and classified in a very transparent and straightforward way into
four types. The analytical solutions to orbit, time, and proper time equations are given for all orbit types in the form r = r(λ), t = t(χ), and τ= τ (χ), where λ is the true anomaly and χ is a parameter along the orbit. A very simple relation between λ and χ is also shown.
These solutions are very useful for modelling temporal evolution of transient phenomena near black holes since they are expressed
with Jacobi elliptic functions and elliptic integrals, which can be calculated very efficiently and accurately. 相似文献
9.
We give a generalization of a well-known result of Brualdi concerning eigenvalue localization and compare this generalization with related results in this area. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
10.
The aim of the present work was to investigate iron, cobalt and chromium distribution in samples of living and non-living
matter by using instrumental neutron activation analysis (INAA). Investigations were carried out starting with water systems
components, such also specias living in these systems and biological tissues from rat and human organs. The following conclusions
have been drawn for elements distribution in the relation enviromment/living matter: (1) iron, cobalt and chromium contents
in plankton are very close to these found in suspended materials; (2) among all the investigated living organisms, the highest
contents of investigated elements have been found in fish; (3) inspite of the contents of iron, cobalt and chromium being
somewhat lower in bentos and crustacea than in suspended materials, all the obtained values are very close, and (4) human
liver has somewhat higher iron- and cobalt-contents than rat liver, which, however, has higher chromium concentration. Of
all the investigated living organisms chromium content was the lowest in human liver. 相似文献