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21.
Boumediene Abdellaoui Tarik Mohamed Touaoula 《NoDEA : Nonlinear Differential Equations and Applications》2010,17(3):271-288
In this paper we consider age structured equation with diffusion under nonlocal boundary condition and nonnegative initial
data. We prove existence, uniqueness and the positivity of the solution to the above problem. Our main result is to get an
exponential decay of the solution for large times toward such a study state. To this end we prove a weighted Poincaré–Wirtinger’s
type inequality in unbounded domain. 相似文献
22.
Jeramy Dickerson Konstantinos Pantzas Tarik Moudakir Abdallah Ougazzaden Paul L. Voss 《Optical and Quantum Electronics》2013,45(7):681-686
We report the numerical study of n-GaN/i-InGaN/p-GaN solar cells on Ga-face substrates with thin GaN interlayers present in the intrinsic InGaN region. These interlayers have recently been shown to significantly increase the crystal quality of thick InGaN layers $(>\!\!\!120\,\text{ nm})$ . We find that tunneling is efficient in n-i-p structures having interlayers $\le \! 1.5\,\text{ nm}$ thick if polarization charges are sufficiently screened. If left unscreened, the large polarization charges naturally formed at the heterointerfaces degrades n-i-p performance, at a given interlayer thickness, because polarization charges increase the distance that carriers must tunnel. Simulations identify favorable parameter ranges. 相似文献
23.
Quantitative Fourier‐transform infrared spectroscopic analysis was used for the determination of adsorption capacity of a model volatile organic compound (VOC) under dynamic conditions. The analytical method used also offers the possibility of distinguishing between reversible and irreversible adsorption as well as further detection of adsorbed VOC transformation. The obtained adsorbed amounts have been used for the determination of the heat of adsorption and the activation energy of desorption using, respectively, isosteric and temperature programmed desorption methods. The approach has been applied to explore the potential use of local clay as an adsorbent material for VOC pollutants. 相似文献
24.
Tarik E. Ali Mohammed A. Assiri Noha M. Hassanin I. S. Yahia Mai S. A. Hussien 《Journal of heterocyclic chemistry》2019,56(5):1684-1686
Novel diethyl (4‐oxo‐3,4‐dihydro‐2H‐chromeno[2,3‐d]pyrimidin‐2‐yl)phosphonate as two enantiomers and diethyl (4‐oxo‐1,5‐dihydro‐4H‐chromeno[2,3‐d]pyrimidin‐5‐yl) phosphonate were obtained in easy procedure via reaction of 2‐imino‐2H‐chromene‐3‐carboxamide, dimethylformamide dimethyl‐acetal, and diethyl phosphite in a simple one pot. Possible reaction mechanisms were proposed. The structures of the obtained products were confirmed by elemental analyses and spectral tools. 相似文献
25.
The chemical reactivity of 3-(dimethylamino)-1-(2-hydroxyphenyl)prop-2-en-1-one (1) towards some phosphorus reagents was studied. The enaminone 1 was cyclized into diethyl 2-phosphonochromone 2 via its treatment with diethyl phosphite in basic medium. However, its reaction with triethoxy phosphonoacetate gave the substituted pyrone phosphonate 3. In addition, two novel examples of 4-(dimethylamino)-6-(2-hydroxyphenyl)-2-sulfido-4H-1,3,2-oxathia-phosphinines 6 and 7 were obtained from treatment of enaminone 1 with O,O-diethyl dithiophosphoric acid and Lawesson’s reagent. When enaminone 1 was also treated with phosphorus decasulfide, it was turned into 4H-thiochromene-4-thione while its treatment with phosphorus tribromide, phosphorus oxychloride, or phenylphosphonic dichloride, 4H-4-oxo-chromene was isolated in all cases. The possible reaction mechanisms of the formation of these products were discussed. The structures of newly isolated products were established by elemental analysis and spectral tools. 相似文献
26.
Achraf El Kasmi Henning Vieker Ling-nan Wu André Beyer Tarik Chafik Zhen-yu Tian 《化学物理学报(中文版)》2019,32(3):365-372
Thin cuprous oxide films have been prepared by chemical vapor deposition (pulsed spray evaporation-chemical vapor deposition) method without post-treatment. The synthesis ofcuprous oxide was produced by applying a water strategy effect. Then, the effect of water on the morphology, topology, structure, optical properties and surface composition of the obtained films has been comprehensively investigated. The results reveal that a pure phase of Cu2O was obtained. The introduction of a small quantity of water in the liquid feedstock lowers the band gap energy from 2.16 eV to 2.04 eV. This finding was mainly related to the decrease of crystallite size due to the effect of water. The topology analyses, by using atomic force microscope, also revealed that surface roughness decreases with water addition, namely more uniform covered surface. Moreover, theoretical calculations based on density functional theory method were performed to understand the adsorption and reaction behaviors of water and ethanol on the Cu2O thin film surface. Formation mechanism of the Cu2O thin film was also suggested and discussed. 相似文献
27.
The aim of this work is to derive an accurate model of two-dimensional switched control heating system from data generated by a Finite Element solver. The nonintrusive approach should be able to capture both temperature fields, dynamics and the underlying switching control rule. To achieve this goal, the algorithm proposed in this paper will make use of three main ingredients: proper orthogonal decomposition (POD), dynamic mode decomposition (DMD) and artificial neural networks (ANN). Some numerical results will be presented and compared to the high-fidelity numerical solutions to demonstrate the capability of the method to reproduce the dynamics. 相似文献
28.
Fatih Yaar Tarik elik Bernd A. Berg Hagai Meirovitch 《Journal of computational chemistry》2000,21(14):1251-1261
The multicanonical (Muca) Monte Carlo method enables simulating a system over a wide range of temperatures and thus has become an efficient tool for studying spin glasses, first‐order phase transitions, the helix–coil transition of polypeptides, and protein folding. However, implementation of the method requires calculating the multicanonical weights by an iterative procedure that is not straightforward and is a stumbling block for newcomers. A recursive procedure that takes into account the statistical errors of all previous iterations and thus enables an automatic calculation of the weights without the need for human intervention after each iteration has been proposed. This procedure, which has already been tested successfully for lattice systems, is extended here to continuum models of peptides and proteins. The method is examined in detail and tested for models of the pentapeptide Leu‐enkephalin (Tyr‐Gly‐Gly‐Phe‐Leu) described by the potential energy function ECEPP. Because of the great interest in the structural mapping of the low‐energy region of biomolecules, the energy of structures selected from the Muca trajectory is minimized. The extent of conformational coverage provided by the method is examined and found to be very satisfactory. © 2000 John Wiley & Sons, Inc. J Comput Chem 21: 1251–1261, 2000 相似文献
29.
Terephthalic acid hydrazide ( 1 ) was reacted with phenylphosphonic dichloride to yield bis(1,3,4,2‐oxadiazaphosphole) derivative 3 , which was condensed with α‐aminophosphonic acid derivative 4 to afford bis[(1,2,4,3‐triazaphospholyl)(chromonyl)methylphosphonic acid] derivative 5 . The addition of diethyl phosphite to Schiff bases 9 and 10 derived from the condensation of bis(4‐amino‐1,2,4,3‐triazaphosphole) derivative 6 or bis(4‐phosphorylamino‐1,2,4,3‐triazaphosphole) derivative 7 with 3‐formyl‐6‐methylchromone ( 8 ) yielded bis[(1,2,4,3‐triazaphospholyl)(chromonyl)aminomethylphosphonate] derivative 11 and bis[(1,2,4,3‐triazaphospholyl)(chromonyl)phosphorylamino‐methylphosphonate] derivative 12 , respectively. The structures of all products were established by elemental analysis and spectral data. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:117–122, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20520 相似文献
30.
Tarik E. Ali 《Phosphorus, sulfur, and silicon and the related elements》2016,191(9):1223-1228
Mass fragmentation pathways of eight synthetic organophosphorus compounds, belonging to azolyl, azinyl, and azepinyl phosphonates as cyclic α-aminophosphonates 1a,b–4a,b were investigated by electron impact mass spectrometry with the aim of obtaining a better understanding of their fragmentation processes. The intensity of the recorded molecular ion peaks showed moderate values. Compounds 1a,b–3a,b have almost identical fragmentation routes via easy elimination of phosphonate groups which can be fragmented into the cation PO2 as base peaks. On the contrary, compounds 4a,b started their fragmentation via removal of 4-chlorophenyl moieties. 相似文献