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排序方式: 共有260条查询结果,搜索用时 15 毫秒
1.
Ullah Malik Zaka Muhammad Taseer Mallawi Fouad 《Journal of Thermal Analysis and Calorimetry》2021,143(3):2411-2418
Journal of Thermal Analysis and Calorimetry - This paper provides a theoretical study of 3D nanofluid flow with zero nanoparticles mass and constant heat fluxes conditions. An incompressible... 相似文献
2.
3.
Chemistry of Phosphorus Ylides. Part 37. The Reaction of Phosphonium Ylides with Indoles and Naphthofurans. Synthesis of Phosphanylidenes,Pyrans, Cyclobutenes,and Pyridazine as Antitumor Agents 下载免费PDF全文
Soher S. Maigali Marwa El‐Hussieny Fouad M. Soliman 《Journal of heterocyclic chemistry》2015,52(1):15-23
The reaction of the stabilized phosphonium ylides 2a , 2b with indolinones 1a , 1b and naphthofuranone 13 afforded the corresponding propylidene and ethylidene derivatives 4a , 4b , 4c , 4d and 14a , 14b . On the other hand, the active phosphacumulenes 5a , 5b react with compounds 4a , 4b , 4c , 4d by [4 + 2]‐cycloaddition to give the stable phosphanylidene indole pyranones 6a , 6b , 6c , 6d , 6e , 6f , 6g , 6h . Although compounds 14a , 14b afforded the naphthofuropyrans 16a , 16b , 16c , 16d and triphenylphosphane. Moreover, the phosphallene ylide 7 react with compounds 4a , 4b , 4c , 4d and 14a , 14b to give phosphanylidenecyclobuteneindoline 9a , 9b , 9c , 9d and naphthalenones 18a , 18b , respectively. In addition, the naphthofuropyridazine 21 was obtained from the reaction of the hydrazone 19 and the phosphacumulene 5a . The antitumor activity of some of the new compounds was evaluated, in vitro, against colon and hepatocellular carcinoma cell lines. They showed values closed to that recorded by the reference drug Doxorubicin. 相似文献
4.
Utilisation of Anagrus nilaparvatae is a promising and effective method for planthoppers manipulation. Twenty-seven components of remote lemongrass (Cymbopogon distans) oil were identified by GC/MS and nine volatiles were selected for behavioural experiments. In this study, we noted that the remote lemongrass oil was attractive to female A. nilaparvatae at concentrations of 0.1 and 1 mg/L. α-Pinene, β-pinene, eucalyptol, carveol and D-carvone attracted female wasps in the dose-dependent bioassays. Blend 1 (a mixture of eucalyptol, D-carvone, carveol, α-pinene, and β-pinene with ratios of remote lemongrass oil volatiles of 625:80:11:5:3) attracted female wasps at 10 mg/L, while blend 2 (a mixture of the same five volatiles at the same loading ratio) attracted them at 0.1 and 1 mg/L. These results suggested that plant essential oils could be attractants for natural enemies to control pests. The ratios of volatiles in the mixtures affect the attractiveness of the synthetic mixtures. 相似文献
5.
Ayman Ben Mabrouk Hamid Kaddami Sami Boufi Fouad Erchiqui Alain Dufresne 《Cellulose (London, England)》2012,19(3):843-853
The microstructure and chemical composition of alfa (Stipa tenacissima) were investigated. The polysaccharide and lignin contents were around 70 and 20 wt%, respectively. From the bleached and
delignified fibers, two types of nanosized cellulosic particles were extracted, namely cellulose nanocrystals and microfibrillated
cellulose (MFC). The former correspond typically to the elementary crystallite units of the cellulose fibers, with a rod-like
morphology and an aspect ratio of about 20. The latter, mechanically disintegrated from oxidized bleached fibres, presents
an entangled fibrillar structure with widths in the range 5-20 nm. The reinforcing potential of the ensuing nanoparticles
was investigated by casting a mixture of acrylic latex and aqueous dispersion of cellulose nanoparticles. Thermo-mechanical
analysis revealed a huge enhancement of the stiffness above the glass transition of the matrix. Significant differences in
the mechanical reinforcing capability of the nanoparticles were reported. 相似文献
6.
I. S. Yahia G. B. Sakr S. S. Shenouda M. Fadel S. S. Fouad F. Yakuphanoglu 《Applied Physics A: Materials Science & Processing》2013,112(2):275-282
The negative capacitance (NC) behavior in p-ZnGa2Se4/n-Si nano-crystalline HJD was characterized by admittance-voltage method. The C–V, G–V and R s –V for the studied diode were analysed in the frequency range of 1–5 MHz and in the temperature range of 303–423 K. The capacitance and conductance plots were interpreted in terms of interface states and series resistance. The C–V and G/ω–V plots exhibit a pounced peak due to the interface states and the series resistance effects. The negative capacitance behavior in the studied diode can be explained in terms of the transient currents. 相似文献
7.
Fouad Laoutid Marion Lorgouilloux Didier Lesueur Leila Bonnaud Philippe Dubois 《Polymer Degradation and Stability》2013
In this study, we evaluated the potential flame retardant effect of calcium-based hydrated minerals, such as hydrated lime, partially and completely hydrated dolomitic limes in polyethylene (MDPE) and ethylene vinyl acetate copolymers (EVA) and compared to that obtained with magnesium di-hydroxide (MDH). The most significant flame retardant effects, observed using the mass loss calorimeter test, indicated that Ca-based MDPE composites showed similar peak Heat Release Rate (pHRR) level to that obtained with MDH composite while the pHRR was lower for Ca-based fillers in EVA compositions. X-ray Diffraction (XRD) data, combined with thermal analysis results, indicated that the calcium di-hydroxide plays a role in the formation of an intumescent cohesive residue during the combustion. Indeed, Ca(OH)2 reacts with CO2 formed during the thermal degradation of the polymer to generate CaCO3 (calcium carbonate) that contributes to the enhancement of the mechanical resistance of the residue. 相似文献
8.
Fouad El-Diasty 《Vibrational Spectroscopy》2011,55(1):1-37
In this review the basis, recent developments and applications of coherent anti-Stokes Raman scattering (CARS) in the fields of spectroscopy and microscopy are dialed with. The nonlinear susceptibility of the investigated molecule induced by pump and Stokes laser beams employed in the CARS technique is discussed. The relation between the nonlinear susceptibility, the different CARS laser intensities and the phase matching condition between them is also presented. The structure of CARS spectrum is analyzed as a function of the physical characteristics of the different employed lasers. This includes laser half widths, interference effects, cross-coherence and saturation of the resultant CARS signal by stimulated Raman scatter process (SRS). The different broadening mechanisms for CARS spectral line such as pressure and Doppler broadening are demonstrated. The recent progress in CARS for the in situ reaction flame diagnosis due to its suitability for detection of vibrational-rotational excited gas molecules present in the electronic ground state is discussed. CARS diagnosis for liquid- and solid-phases including the progress in polymeric materials is considered. The applications of CARS microscopy are reviewed in the view of its recent advances to study chemical and biological systems. 相似文献
9.
In this paper, we study pseudo-slant submanifolds and their warped products in Kenmotsu manifolds. We obtain the necessary conditions that a pseudoslant submanifold is locally a warped product and establish an inequality for the squared norm of the second fundamental form in terms of the warping function. The equality case is also considered. 相似文献
10.
Ayman M. Atta Ahmed A. Fadda Adel A.-H. Abdel-Rahman Husein S. Ismail Rasha R. Fouad 《Journal of Dispersion Science and Technology》2013,34(6):775-785
Water soluble nonionic amphiphilic block copolymers based on hydrophilic poly(ethylene glycol) (PEG) and hydrophobic poly(propylene glycol) (PPG) were prepared. Poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) copolymers, PEG-PPG-PEG, were prepared in the normal condition. The chemical composition and molecular weights of the prepared copolymers were determined from 1H NMR and GPC techniques. The surface properties of the prepared surfactants were determined by measuring the surface tension at different temperatures. The prepared nonionic surfactants were evaluated as demulsifiers for water in crude-oil emulsions that were pronounced at different ratios of crude oil: water at 318 K and 333 K. The experimental results showed that the dehydration rate of the prepared demulsifiers reached 100% based on demulsifier chemical compositions and concentrations. 相似文献