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排序方式: 共有537条查询结果,搜索用时 46 毫秒
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2.
Saleh Z. M. Nasser H. Özkol E. Günöven M. Abak K. Canli S. Bek A. Turan R. 《Journal of nanoparticle research》2015,17(10):1-12
Journal of Nanoparticle Research - Plasmonic interfaces consisting of silver nanoparticles of different sizes (50–100&;nbsp;nm) have been processed by the self-assembled dewetting... 相似文献
3.
Muhammad Asif Hanif Ahmed Yahya Al-Maskari Jamal Nasser Al-Sabahi Ibtisam Al-Hdhrami Muhammad Mumtaz Khan Ahlam Al-Azkawi 《Natural product research》2015,29(24):2332-2335
Medicago sativa Linn growing in Omani desert were chemically characterised using flame photometry, inductively coupled plasma, gas chromatography–mass spectrometry and high performance liquid chromatographic (HPLC) analysis. HPLC analyses were performed to determine the phenolics and flavonoids present in M. sativa. The major compounds detected in M. sativa leaves were protchaechenic acid (3.22%), hydroxyl benzoic acid (1.05%), β-Phenyl caffate (0.97%) and kaempherol (0.89%). Pterostilbene, a cholesterol-lowering compound, was detected in M. sativa. 相似文献
4.
Payam Osooli Yadollah Yamini Mahmoud Tabibpour Seyedeh Sara Nasrollahi Nasser Nikfarjam 《Journal of separation science》2023,46(22):2300421
In the present work, a novel solid-phase microextraction on a screw (MES) was employed to extract cationic dyes (malachite green, methylene blue, and rhodamine B) from food samples and fish breeding pool water. The sulfonated poly(styrene-co-divinylbenzene) was electrophoretically deposited on the surface of the grooves of a screw. Then the screw was placed inside a silicon tube as a holder to create a channel to run a test solution through it. The extracted dyes on the coated screw were eluted by a suitable eluent. High-performance liquid chromatography with an ultraviolet/visible detector was utilized for the separation and analysis of the analytes. The effective parameters of the analyte extraction efficiency were optimized. Under optimum conditions, the limits of detection were 0.15 μg/L, and calibration curves were linear in the range of 0.50–250.00 μg/L, with coefficients of determination > 0.989 for all studied dyes. The relative standard deviations of intra and inter-day (n = 3) were in the range of 2.8%–7.0% and 7.0%–9.5%, respectively. The MES was applied as a simple and repeatable method with acceptable relative recoveries (82.0%–103.0%) for the determination of cationic dyes in grape nectar, ice pop, jelly powder, and fish breeding pool water. 相似文献
5.
This paper experimentally investigates the influence of carbon nanotubes (CNTs) on phase composition, microstructure deterioration, thermal behavior, and residual mechanical strengths of cementitious composites exposed to elevated temperatures. Cement mortars with small dosages of CNTs, 0.05% and 0.2% by weight of cement, were prepared and then heated at 25 °C, 150 °C, 200 °C, 450 °C, and 600 °C for two hours before being tested. The results show positive impact of the CNTs on the hydration process of cement mortar at room temperature and at higher temperatures up to 200 °C. Decomposition of the hydration products is obvious at 450 °C, whereas sever deterioration in the microstructure occurs at 600 °C. The nano reinforcement and bridging effect of the CNTs are obvious up to 450 °C. Thermal behavior characterization shows that CNTs incorporation enhances the thermal conductivity of the unheated and heat-treated mortar specimens. The decomposition of the hydration products needs more heat in the presence of CNTs. Finally, presence of CNTs significantly enhances the residual compressive and flexural strengths of heated mortar specimens for all studied temperatures. 相似文献
6.
Safari Nasimeh Imanzadeh Gholamhassan Asgharzadeh Roghayyeh Hosseyni Seyyedeh Tahereh Shamkhali Amir Nasser Soltanzadeh Zahra 《Chemistry of Heterocyclic Compounds》2021,57(6):640-645
Chemistry of Heterocyclic Compounds - In this work, new pyrazole derivatives were prepared by one-pot three-component reaction emloying symmetric and asymmetric 1,2-disulfonyl-hydrazines,... 相似文献
7.
Mohammad Nasser H. EL-Sherbiny Gamal M. Hammad Ali A. Askar Ahmed A. El- Nour Salwa A. Abou 《Cellulose (London, England)》2022,29(3):1791-1805
Cellulose - Antibacterial coatings based on bacterial cellulose (BC) have been widely used in many fields including food packaging and wound dressing. In this study, we aimed to synthesis of... 相似文献
8.
Olivier Gicque Dominique Thévenin Nasser Darabiha 《Flow, Turbulence and Combustion》2005,73(3-4):307-321
In this paper we wish to investigate the occurrence of super-equilibrium temperature values, observed in many experimental
configurations. We would like to understand the origin of this phenomenon. Previous authors have already shown that differential
diffusion can lead to considerable changes in the temperature field and we would like to build on top of this observation.
We investigate numerically super-equilibrium combustion by considering both laminar counter-flow and turbulent diluted hydrogen/air
diffusion flames. These turbulent flames are computed using direct numerical simulations (DNS). A detailed reaction mechanism
is employed and the transport properties are modeled using multicomponent diffusion velocities, including the Soret effect.
Analyzing these results we introduce three complementary parameters (dilution-free mixture fraction, dilution excess and local
enthalpy) to describe the local combustion conditions. Introducing a measure of dilution separately from the mixture fraction
is necessary for a proper analysis. Using this set of parameters it becomes possible to explain super-equilibrium temperature
levels as a consequence of differential diffusion. 相似文献
9.
Marzieh Saeedi Maryam Anafcheh Reza Ghafouri Nasser L. Hadipour 《Structural chemistry》2013,24(2):681-689
Density functionla theory (DFT) calculations are performed to characterize geometric and electronic features of the octahedral Al n N n and Al n P n cages (n = 12, 16, 28, 32, and 48). Toward this aim, 15N, 27Al, and 31P chemical shielding (CS) tensors as well as natural charge analyses are calculated for the optimized structures. CS parameters detect three distinct electronic environments for atoms within the Al n N n and Al n P n cages. The chemical shifts of N2 sites belonging to a hexagon and surrounded by three hexagons and a square obtained are different from those of N3 sites belonging to a hexagon that is surrounded only by hexagons—due to different curvatures exerted at the sites with different local structures. In addition, there is an increasing tendency in the Δσ values of the three local structures, Δσ (N1) > Δσ (N2) > Δσ (N3), N1 sites belonging to four-membered rings. The chemical shieldings of those Al and P sites belonging to a hexagon that is surrounded only by hexagons in the cages (360.7–366.7 and 496.5–514.7 ppm) are close to those previously reported for AlP nanotubes. Three distinct electrostatic environments around the N, Al, and P nuclei are also confirmed by the calculated natural charges. It should be noted that the positively charged Al atoms on the cages turn out to be the available sites for adsorption of H2 molecules. 相似文献
10.
Silicon-containing condensation polymers were prepared starting from difunctional silicon-containing carboxylic acids or diols derived from long-chain fatty acids. Polyesters were synthesized by reaction of diacids containing siloxane linkages with diols, and diols containing siloxane linkages with various diacids. 1,3-Bis (10-carboxydecyl)tetramethyldisiloxane was condensed with various diamines to yield polyamides. 1,3-Bis(11-hydroxyundecyl)tetramethyldisiloxane and 1,3-bis [9(10)-hydroxyoctadecyl]tetramethyldisiloxane were condensed with diisocyanates to yield polyurethanes. Polycarbonates were synthesized by reacting the diols containing siloxane linkages with ethyl chloroformate. Some polybenzimidazols were synthesized by heating the diesters of the silicon-containing carboxylic acids with 3,3′ -diaminobenzidine. Some of the polyurethanes and polybenzimidazoles were thermally stable up to 300°C as indicated by TGA. 相似文献