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71.
Masoumeh Ighaei Bonab Jaber Jahanbin Sardroodi Alireza Rastkar Ebrahimzadeh Faramarz Mehrnejad 《Journal of the Iranian Chemical Society》2017,14(2):357-364
Structural modification of curcumin represents a strategy to improve its stability, water solubility, pharmaceutical properties and bioactivity. In this context, numerous structural analogues of curcumin, including curcuminoids, have been developed. In this paper, the precise density functional theory computations were used for investigating the electronic and geometrical structure of curcumin and some of its derivatives. The chemical activity of the considered molecules was investigated with the help of the global softness and hardness concepts. Among the studied molecules, bisdemethoxycurcumin had the most chemical activity and hexahydrocurcumin had the most stable structure. Among two isomers of the curcumin, the enol isomer was found to be active. 相似文献
72.
Thermodynamic simulation of performance of a dual cycle with stroke length and volumetric efficiency
This article presents finite-time thermodynamics analysis of an irreversible air standard dual cycle. An irreversible dual cycle model which is more close to practice is established. In this model, the effects of stroke length and volume efficiency by considering the nonlinear relation between the specific heats of working fluid and its temperature, the frictional loss, the internal irreversibility, and heat transfer loss are analyzed. The results show that if compression ratio is less than certain value, the power output increases with increasing stroke length, while if compression ratio exceeds certain value, the power output first increases and then starts to decrease with increasing stroke length. With further increase in compression ratio, the increase of stroke length results in decreasing the power output. The results also show that, throughout the compression ratio range, the power output increases with the increasing volumetric efficiency. The results obtained in this study are of importance to provide good guidance for performance evaluation and improvement of practical internal combustion engines. 相似文献
73.
Structural Chemistry - In this study, density functional theory (DFT) was employed to predict thermochemical and energetic properties for single-walled carbon nanotubes (SWCNTs) decorated with one... 相似文献
74.
Nader Noroozi Pesyan Alireza Shokr Mohammad Behroozi Ertan Şahin 《Journal of the Iranian Chemical Society》2013,10(3):565-575
Reaction of 5,5-dimethylcyclohexane-1,3-dione (dimedone), aldehydes and cyanogen bromide in the presence of triethylamine leads to the selective formation of spiro dihydrofurans in moderate to good yields at room temperature. 相似文献
75.
Fe3O4 magnetic nanoparticles functionalized with 5,10‐dihydropyrido[2,3‐b]quinoxaline‐7,8‐diol were synthesized as was their complex with copper as a novel nanomagnetic iron oxide catalyst via a simple and green method, and characterized using various techniques. The capability of the catalyst was evaluated in the one‐pot three‐component synthesis of different tetrazoles, which showed very good results. Mild reaction conditions, good reusability and simple magnetic work‐up make this methodology interesting for the efficient synthesis of tetrazoles. 相似文献
76.
Silver nanoparticles immobilized onto poly(4‐vinylpyridine)‐functionalized magnetic nanoparticles: A robust magnetically recyclable catalyst for oxidant‐free alcohol dehydrogenation 下载免费PDF全文
A heterogeneous and recyclable catalyst with a high loading of silver nanoparticles was synthesized via the silver nanoparticles being supported onto the surface of magnetic nanoparticles coated with poly(4‐vinylpyridine). The synthesized catalyst was used in the dehydrogenation of alcohols to corresponding carbonyl compounds. A broad diversity of alcohols was converted into their corresponding carbonyl compounds in excellent yields. The catalyst was easily recovered by applying an external magnetic field and reused for seven reaction cycles without considerable loss of activity. The catalyst was fully characterized using various techniques. 相似文献
77.
Hormoz Eslami Soleyman Hosseinzadeh Younes Saadat Faramarz Afshar-Taromi Mehdi Rimaz 《Colloid and polymer science》2012,290(14):1463-1469
In this work, the preparation of micron-sized polymer particles with nonspherical shapes via seeded dispersion polymerization of 2-ethylhexyl methacrylate (EHMA) with polystyrene (PS) seed particles in the presence of decane droplets and evaporation of decane after the polymerization under various polymerization conditions was discussed. The effect of monomer and decane content and polarity of the medium on the shape of the obtained particles was investigated. The experimental results showed that decreasing the amount of monomer and hydrocarbon volume of PEHMA/hydrocarbon domains, the particles decreased but they grew symmetrically, resulting in symmetric shapes. Furthermore, it was suggested that because of changing the solubility of the oligoradicals and hydrocarbon in the medium, the shape of the particles changed with changing the polarity of the medium. With decreasing the polarity of the medium, solubility of the oligoradicals in the medium increases and bigger polymer domains form on the surface of PS particles which can absorb higher amounts of decane. All of these can contribute to an increase in volume reduction after extraction of PEHMA/decane, resulting in various particle shapes. Further decreasing in polarity of the medium leads to an increase in the solubility of decane in the medium and decreasing the absorbed amount of decane by PS particles and PEHMA domains, resulting in lower volume reduction after evaporation of decane. 相似文献
78.
79.
Zahra Taji Ali A. Ensafi Elahe Heydari-Soureshjani Behzad Rezaei 《Electroanalysis》2021,33(2):304-313
In this work, a modified 3D-rGO/MWCNT with nickel and copper oxide nanoparticles were synthesized. The structural properties of this nanocomposite were investigated by several techniques. The fabricated sensor at optimum condition potential of +0.60 V (vs. Ag/AgCl) and a rotational rate of 1800 rpm gave a detection limit of 0.04 μmol L−1 with two dynamic ranges of 0.10–300 and 300–900 μmol L−1 glucose with high stability. The good accuracy of the fabricated sensor was proved in the determination of glucose in a blood sample (with recoveries between 95 % to 105 % and RSDs of 1.2 to 2.5 %). 相似文献
80.
Faezeh Pourebrahim Mehrorang Ghaedi Kheibar Dashtian Shadi Kheirandish Ramin Jannesar Vahid Pezeshkpour 《应用有机金属化学》2018,32(1)
In this work, functionalized chitosan end‐capped Ag nanoparticles (NPs) and composited with Fe3O4‐NPs was prepared as pH‐responsive controlled release carrier for gastric‐specific drug delivery. The structure of prepared material was characterized by FE‐SEM, XRD, EDS and FT‐IR analysis. The loading behavior of the progesterone onto this novel material was studied in aqueous medium at 25°C and their release was followed spectrophotometrically at 37°C in seven different buffer solutions (pH 1.2, 2.2, 3.2, 4.2, 5.2, 6.2 and 7.2) to simulate intestine and gastric media which experimental results reveal more release rate in pH 1.2 (gastric medium) with respect to other buffers. This observation is attributed to dependency of the CS‐IMBDO‐Ag‐Fe3O4‐NPs and progesterone structure with buffer pH that candidate this new material as prospective pH‐sensitive carrier for gastric‐targeted drug delivery. On the other hand, the antibacterial properties of this material against gram‐negative bacterium pseudomonas aeruginosa (PAO‐1) in agar plates was studied and accordingly based on broth micro dilution the minimum bactericidal concentration (MBC) and minimum inhibitory concentration (MIC) with respect to standard CLSI in different concentrations of CS‐IMBDO‐Ag‐Fe3O4‐NPs was calculated. The results reveal that MIC and MBC values are 50 and 1250 μg/mL, respectively. In addition, extracts of Portulaca oleracea leaves was prepared and its antibacterial activity in single and binary system with CS‐IMBDO‐Ag‐Fe3O4‐NPs as synergies effect against PAO‐1 was tested and results shown that these materials have significant synergistic effect for each other. 相似文献