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991.
992.
Mohamed El Otmani 《Journal of Theoretical Probability》2009,22(3):601-619
In this paper, we study the reflected solution of one-dimensional backward stochastic differential equation driven by Teugels
martingales and an independent Brownian motion. We prove the existence and uniqueness of the solution using a penalization
method combined with Snell envelope theory.
相似文献
993.
R.A. Mohamed Ibrahim A. Abbas S.M. Abo-Dahab 《Communications in Nonlinear Science & Numerical Simulation》2009,14(4):1385-1395
An analysis is carried out to study the flow, chemical reaction and mass transfer of a steady laminar boundary layer of an electrically conducting and heat generating fluid driven by a continuously moving porous surface embedded in a non-Darcian porous medium in the presence of a transfer magnetic field. The governing partial differential equations are converted into ordinary differential equations by similarity transformation and are solved numerically by using the finite element method. The results obtained are presented graphically for velocity, temperature and concentration profiles, as well as the Sherwood number for various parameters entering into the problem. 相似文献
994.
Abdelhak Fahsi Mohamed Belhaq Faouzi Lakrad 《Communications in Nonlinear Science & Numerical Simulation》2009,14(4):1609-1616
This paper examines the suppression of hysteresis in a forced nonlinear self-sustained oscillator near the fundamental resonance. The suppression is studied by applying a rapid forcing on the oscillator. Analytical treatment based on perturbation analysis is performed to capture the entrainment zone, the quasiperiodic modulation domain and the hysteresis area as well. The analysis leads to a strategy for the suppression of hysteresis occurring between 1:1 frequency-locked motion and quasiperiodic response. This hysteresis suppression causes the disappearance of nonlinear effects leading to a smooth transition between the quasiperiodic and the frequency-locked responses. Specifically, it appears that a rapid forcing introduces additional apparent nonlinear stiffness which can effectively suppress hysteresis in a certain range of the rapid excitation frequency. This work was motivated by the important issue of controlling and eliminating hysteresis often undesirable in mechanical systems, in general, and in application to microscale devices, especially. 相似文献
995.
996.
997.
This paper introduces a Grammar-based Genetic Programming Hyper-Heuristic framework (GPHH) for evolving constructive heuristics for timetabling. In this application GP is used as an online learning method which evolves heuristics while solving the problem. In other words, the system keeps on evolving heuristics for a problem instance until a good solution is found. The framework is tested on some of the most widely used benchmarks in the field of exam timetabling and compared with the best state-of-the-art approaches. Results show that the framework is very competitive with other constructive techniques, and did outperform other hyper-heuristic frameworks on many occasions. 相似文献
998.
Wagner B Schumann D Linne U Koert U Marahiel MA 《Journal of the American Chemical Society》2006,128(32):10513-10520
Heterocycles display common structural motifs in nonribosomally produced peptides with an enormous impact on their bioactivity. In the case of the branched cyclic Bacitracin A, the thiazoline moiety is manufactured during NRPS peptide chain elongation. Here we describe a method to selectively alter the heterocyclic metal binding subunit of Bacitracin A by the synthesis of heterocyclic building blocks that were successfully coupled to the linear decapeptide and subsequently cyclized using the excised bacitracin PCP-TE bidomain. Utilization of this cyclase allowed the first generation of branched cyclic bacitracin derivatives containing thiazole and oxazoles. The generated bacitracin derivatives showed bactericidal activity, indicating the possibility of altering the biological important heterocyclic subunit and overcoming existing limitations for the application of bacitracin. 相似文献
999.
Safir I Castellote I Porcel S Kaoudi T Birlirakis N Toupet L Arseniyadis S 《Chemistry (Weinheim an der Bergstrasse, Germany)》2006,12(28):7337-7344
Oxidative cleavage with lead tetraacetate results in the synthesis of different oxygen heterocycles starting from the same unsaturated 1,2-diol of type I by tuning of the substitution pattern at the angular position. When this compound bears a functional substituent, such as an alkoxy, ester, alkenyl, or simply a hydrogen, more than one reaction pathway are in competition. The process allows for the selective formation of three different complex ring systems, by the appropriate choice of the angular substituent, leading to either a ring-expanded type 1, ring-retained type 2, or domino products 3. 相似文献
1000.
Cellulose fibres were grafted with aliphatic anhydrides having C6, C8, C12 and C16 chain length using a heterogeneous solvent
exchange acylation procedure. The ensuing materials were fully characterised by FTIR, solid state 13C-NMR, Wide-angle X-ray scattering and contact angle measurements. These techniques showed that the chemical coupling has
indeed occurred. The prepared modified fibres appeared to be efficient to trap different organic molecules dissolved in water.
Recycling tests revealed that the saturated substrates could be regenerated tens of times without loosing their capacity of
absorption of organic contaminants. 相似文献