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151.
152.
Extending the previous work [1], we establish well-posedness results for a more general class of semilinear wave equations with exponential growth. First, we investigate the well-posedness in the energy space. Then, we prove the propagation of the regularity in the Sobolev spaces HS(IR^2) with s 〉 1. Finally, an ill-posedness result is obtained in HS(IR^2) for s 〈 1. 相似文献
153.
Nidal Nasser Reid Miller Amir Esmailpour Abd‐Elhamid M. Taha Tarek Bejaoui 《Wireless Communications and Mobile Computing》2015,15(17):2111-2124
Towards satisfying the requirements of International Mobile Telecommunications–Advanced, both the Institute of Electrical and Electronics Engineers (IEEE) and Third Generation Partnership Project (3GPP) introduced revolutionary wireless technologies, exploiting advanced technologies and architectures. Both IEEE's 802.16 (Worldwide Interoperability for Microwave Access (WiMAX)) and 3GPP's Long Term Evolution have been introduced to accommodate the increasing demand for mobile services and applications. To realize the true potential of these technologies, however, opportunistic frameworks for radio resource management must be designed to exploit the adaptive nature of mobile traffic. The utility optimized quality‐of‐service (QoS) framework proposed in this paper for the mobile WiMAX networks achieves this objective. To maintain support for QoS guarantees, the framework capitalizes on the adaptive nature of WiMAX traffic by individually linking connections with a utility function designed to both uphold the end users’ perceived performance and determine bandwidth allocations by a search tree maximization algorithm. In doing so, bandwidth utilization is maximized for all active connections, and blocking and dropping probabilities for new and handover calls, respectively, are minimized. The framework is evaluated through an extensive simulation model and is shown to outperform state‐of‐the‐art solutions. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
154.
Eric Stern Steven M. Jay Stacey L. Demento Ryan P. Murelli Mark A. Reed Tadeusz Malinski David A. Spiegel David J. Mooney Tarek M. Fahmy 《Advanced functional materials》2009,19(18):2888-2895
Bioactive, patterned micro‐ and nanoscale surfaces that can be spatially engineered for three‐dimensional ligand presentation and sustained release of signaling molecules represent a critical advance for the development of next‐generation diagnostic and therapeutic devices. Lithography is ideally suited to patterning such surfaces due to its precise, easily scalable, high‐throughput nature; however, to date polymers patterned by these techniques have not demonstrated the capacity for sustained release of bioactive agents. Here a class of lithographically defined, electropolymerized polymers with monodisperse micro‐ and nanopatterned features capable of sustained release of bioactive drugs and proteins is demonstrated. It is shown that precise control can be achieved over the loading capacity and release rates of encapsulated agents and this aspect is illustrated using a fabricated surface releasing a model antigen (ovalbumin) and a cytokine (interleukin‐2) for induction of a specific immune response. Furthermore, the ability of this technique to enable three‐dimensional control over cellular encapsulation is demonstrated. The efficacy of the described approach is buttressed by its simplicity, versatility, and reproducibility, rendering it ideally suited for biomaterials engineering. 相似文献
155.
Tarek M. Abu Elmaati 《Journal of heterocyclic chemistry》2004,41(6):947-950
Treating 5‐(4‐phenylcarboxamido)‐3‐cyano‐4‐methylpyridin‐2(1H)thione ( 3 ) with elemental sulfur yielded thienopyridine 4 . Compound 4 reacts with acrylonitrile to give isoquinoline 7 . Compound 7 was also, prepared from 3 and methylenemalononitrile. Reaction of 3 with dimethylacetylene dicarboxylate (DMAD) gave the pyridothiazole 9 . Also, 3 reacted with N,N‐dimethylchloroacetamide ( 10 ) to afford compound 11 which further reacted with the reagents 12 , 13 and 14 providing the thieno[2,3‐b]pyridine derivatives 15 , 16 and 17 respectively. 相似文献
156.
Several isoquinolines were prepared via reacting pyridine 4 with cinnamonitriles 5a‐c or 5d‐f . Treating 4 with elemental sulphur yielded thienopyridine 9. 9 reacts with acrylonitrile to give isoquinoline 12. 12 was also prepared from 4 and methylenemalononitrile. Condensation of 4 with aromatic aldehydes gave the arylidine 13. 13 afforded the pyridine 14 and 15 on treating it with NH4OH and AcOH/HCl, respectively. 相似文献
157.
Mahdy M. Elmahdy Khalid A. Aldhafeeri Moustafa T. Ahmed Maged A. Azzam Tarek Fahmy 《先进技术聚合物》2023,34(2):800-816
Dielectric spectroscopy (DS) measurements were performed to probe the segmental dynamics and ion mobility of poly(vinyl chloride-co-vinyl acetate-co-2-hydroxypropyl acrylate) terpolymer dopped with different amounts of tetrabutylammonium tetrafluoroborate ([TBA] [BF4]) ionic liquid (IL). Differential scanning calorimetry (DSC) was also employed to trace the change in the glass transition temperature (Tg) at different loads of IL. The DSC measurements revealed a remarkable reduction in the PVVH Tg from 344 to 310 K just by adding 20 wt% of IL. The DS measurements revealed three relaxation processes named α, β1, and β2. The α-process is related to the segmental motion of PVVH while the β1 and β2 are due to the restricted local dynamics of side chains. The segmental relaxation times (α-relaxation) speed up with increasing the concentration of IL due to the plasticization effect of IL on polymer chains. The temperature dependence of α-relaxation follows the Vogel-Fulcher-Tammann (VFT) relation with dynamic glass transition between 323 and 294 K in agreement with the DSC measurements. The β1 and β2-relaxations have an Arrhenius temperature dependence. The temperature dependence of ionic conductivity obeys the VFT behavior indicating the coupling between the segmental motion of PVVH chains and ion transport. Polaronic tunneling is the predominant conduction mechanism in PVVH and its composites. The specific capacitance increases with increasing both the temperature and IL concentration. 相似文献
158.
Two simple, rapid and reliable spectrophotometric methods are described for the resolution of the three‐component mixture of amiloride hydrochloride (AMD), hydrochlorothiazide (HCT) and timolol maleate (TIM). The first method involves the use of derivative spectrophotometry with the zero‐crossing technique where AMD was easily determined using its 0D and 1D(Δλ = 6) amplitudes at 365 and 385 nm, respectively, while HCT and TIM were determined by measuring the 3D(Δλ = 6) amplitude at 265 nm and the 1D(Δλ = 8) amplitude at 315.4 nm, respectively. The second method involves the application of the ratio‐spectra zero‐crossing first and second derivative spectrophotometry where two points have been used for the quantification of each compound. For the determination of AMD, HCT was used as divisor and the 1DD (Δλ = 4) and 2DD (Δλ = 6) values at 299.4 and 311 nm, respectively, were plotted against AMD concentration; while — by using TIM as divisor — the 2DD (Δλ = 6) amplitudes at 264.2 and 290 nm were found to be proportional to HCT concentration. TIM was assayed in the mixture using its 1DD (Δλ = 6) amplitudes at 289.8 nm (Divisor was AMD) and 314.8 nm (Divisor was HCT). Synthetic mixtures of different proportions and laboratory‐made tablets were assayed by the proposed methods and the results revealed good accuracy and repeatability of the developed methods. 相似文献
159.
Simple, reliable, sensitive and accurate kinetic spectrophotometric and spectrofluorimetric methods were proposed for the determination of ciprofloxacin hydrochloride (CPX) and norfloxacin (NRX) in pure form and in pharmaceuticals. The methods are based on coupling the studied drugs with 4‐chloro‐7‐nitrobenzo‐2‐oxa‐1,3‐diazole (NBD‐Cl) in the presence of alkaline borate buffer. Spectrophotometric measurement was achieved by recording the absorbance at 477 nm after a fixed time of 20 and 15 min on a water bath adjusted at 70 ± 1 °C for CPX and NRX, respectively. The same product exhibited emission peaks at 540 nm. The different experimental parameters affecting the development and stability of the color were carefully studied and optimized. The absorbance concentration plots were linear over the ranges 3‐18 and 2.5‐15.0 μg/mL for CPX and NRX, respectively, while the fluorescence concentration plots were linear over the ranges 0.06‐0.36 and 0.05‐0.30 μg/mL for CPX and NRX, respectively. The limit of detection of the kinetic method was about 0.2 μg/mL for both drugs while the fluorescence measurement enabled their detection at a concentration of about 0.012 μg/mL. The proposed methods were successfully applied for the assay of the two drugs in their commercial products. The results obtained were statistically compared with those obtained by reference HPLC and spectrophotometric methods. The stoichiometry of the reaction was determined and the reaction pathway was postulated. 相似文献
160.
Tarek Aboul‐Fadl Gopalan Rajeev Arthur D. Broom 《Journal of heterocyclic chemistry》2008,45(2):445-451