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181.
Shahram Moradi Zahra Farahani Azadeh Madadi Fariba Dashtestani Behnoush Alimadadi Saeed Abedini Khorrami 《Phosphorus, sulfur, and silicon and the related elements》2013,188(10):2733-2738
Hartree–Fock (HF) and hybrid density functional theory (B3LYP) calculations were performed on tropylium ion and 19 of its mono- and diheteroatomic derivatives. The aromaticity in this class of compounds is evaluated based on the nucleus independent chemical shift (NICS) values. The NICS values are calculated at the center of the rings NICS (0) and at 1Å above the molecular plane NICS (1). The geometry optimization and NICS calculations were carried out at the HF/6–311+G?? and at the B3LYP/6–311+G (2d, p) density functional level, respectively. These calculations in the effects of heteroatoms such as N, B, P, and Si are considered on aromaticity, molecular properties, NICS values, and structural parameters. 相似文献
182.
Mohsen Taghizadeh Ali Akbar Asgharinezhad Noorallah Samkhaniany Azadeh Tadjarodi Abolfazl Abbaszadeh Mohsen Pooladi 《Mikrochimica acta》2014,181(5-6):597-605
We report that magnetic multiwalled carbon nanotubes functionalized with 8-aminoquinoline can be applied to the preconcentration of Cd(II), Pb(II) and Ni(II) ions. The parameters affecting preconcentration were optimized by a Box-Behnken design through response surface methodology. Three variables (extraction time, magnetic sorbent amount, and pH value) were selected as the main factors affecting sorption, and four variables (type, volume and concentration of the eluent; elution time) were selected for optimizing elution. Following sorption and elution, the ions were quantified by FAAS. The LODs are 0.09, 0.72, and 1.0 ng mL?1 for Cd(II), Ni(II), and Pb(II) ions, respectively. The relative standard deviations are <5.1 % for five separate batch determinations at 30 ng mL?1 level of Cd(II), Ni(II), and Pb(II) ions. The sorption capacities (in mg g?1) of this new sorbent are 201 for Cd(II), 150 for Pb(II), and 172 Ni(II). The composite was successfully applied to the rapid extraction of trace quantities of heavy metal ions in fish, sediment, soil, and water samples. Figure
A schematic diagram for synthesis of functionalized magnetic multiwalled carbon nanotube. 相似文献
183.
A new Schiff-base ligand is prepared by a two-step reaction of 3-formylsalicylic acid and (1R, 2R)-diaminocyclohexane in alcoholic solvents. The 1:1 condensation product exists as a zwitterion in the solid state and forms pleated hydrogen-bonded sheets. Metalation of the ligand with divalent iron, nickel, cobalt, and zinc resulted in the formation of double-stranded monohelices with exclusively M-helicity. Each complex has two tridentate ligands, with the carboxylic acid groups remaining uncoordinated. In the crystal lattice, these complexes form extended M-helical strands through intermolecular hydrogen bonding interactions. Metalation of the ligand with copper salts resulted in a distinctly different type of complex, in which the ligand has transformed into a symmetric tetradentate salen ligand with uncoordinated carboxylic acid groups. 相似文献
184.
Azadeh Nakhai Jan Bergman Jim Raftery John A. Joule 《Journal of heterocyclic chemistry》2008,45(5):1513-1516
185.
Azadeh S. Hashemi Doulabi Hamid Mirzadeh Mohammad Imani Shahriar Sharifi Mohammad Atai Shahram Mehdipour‐Ataei 《先进技术聚合物》2008,19(9):1199-1208
Biodegradable polymers have currently attracted high interest as ideal carriers in drug delivery and tissue engineering applications. In situ forming devices based on these materials will synergistically provide the advantages of the customary prefabricated devices as well as ease of administration. To acheive these objectives, optically transparent and biodegradable macromers based on poly(ethylene glycol) and fumaric acid copolymers were synthesized using propylene oxide as a different proton scavenger to enhance in situ photocrosslinking capability. The macromers in different compositions were then photocured for 300 sec in the presence of a visible light initiator/accelerator couple and also a reactive diluent. Characterization of the macromers and the resulting networks were performed using different spectroscopic, chromatographic, physical, and thermal analysis techniques. The resulted shrinkage strain of the macromers upon photocuring was studied using the bounded disk technique, and initial shrinkage strain rates were obtained by numerical differentiation. Our results suggest that the compositions based on these unsaturated aliphatic polyesters are potentially useful to develop injectable, in situ photocrosslinkable carriers for drug and cell delivery applications. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
186.
The antioxidant, nitric oxide (NO) scavenging and malondialdehyde (MDA) scavenging activities of different Zataria multiflora (ZM) chemotype essential oils (EOs) were investigated. The main components are: ZM1 (carvacrol, p-cymene), ZM2 (carvacrol, p-cymene), ZM3 (carvacrol, p-cymene), ZM4 (linalool), ZM5 (carvacrol, p-cymene, thymol), ZM6 (thymol, carvacrol, p-cymene, γ-terpienene), ZM7 (thymol, p-cymene, γ-terpienene) and ZM8 (carvacrol, linalool, p-cymene, thymol). The antioxidant capacities were estimated to be 863?±?55, 619?±?27, 876?±?32, 38?±?9, 649?±?50, 595?±?40, 696?±?41 and 618?±?9?μg ascorbic acid equivalents per millilitre for ZM1 to ZM8, respectively. The NO scavenging values were estimated to be 54?±?1.2, 50?±?1.4, 63?±?1, 0.60?±?0.1, 53?±?0.7, 53?±?1.5, 38?±?1.1 and 46.5?±?3?μg ascorbic acid equivalents per millilitre for ZM1 to ZM8, respectively. The MDA scavenging values were estimated to be 19?±?1, 9?±?1, 24?±?1, 1.6?±?0.6, 12?±?1, 11.7?±?1, 10?±?1 and 12.5?±?1.3?μg ascorbic acid equivalents per millilitre for ZM1 to ZM8, respectively. Among these EOs, ZM3 with carvacrol and p-cymene had higher antioxidant, NO scavenging and MDA scavenging properties. 相似文献
187.
NIAEI Aligholi SALARI Dariush HOSSEINI Seyed Ali KHATAMIAN Masumeh JODAEL Azadeh 《中国化学》2009,27(3):483-488
Gas phase catalytic combustion of ethyl acetate, as one of volatile organic compounds (VOC), was studied on nanostructure ZSM-5, HZSM-5 and Co-ZSM-5 with different cobalt loadings. Nanostructure of ZSM-5 was determined by XRD, SEM and TEM. Catalytic studies were carried out under atmospheric pressure in a fixed bed reactor. Results showed that the Co-ZSM-5 catalysts had better activity than others and at temperatures below 350 ℃, amount of Co loading was more effective on catalytic activity. The order of conversion of ethyl acetate over different Co loading is as follows: Co-ZSM-5 (0.75 wt%)<Co-ZSM-5 (1.5 wt%)<Co-ZSM-5 (15 wt%)<Co-ZSM-5 (2.8 wt%). Besides the higher the inlet concentration of ethyl acetate, the lower the conversion yield, and oxygen concentration in catalytic oxidation conditions has not so large influence on conversion. Furthermore, the presence of water vapor in inlet gaseous feed has an inhibitive effect on ethyl acetate conversion and at the temperatures above 400˚C, the effect decreases. 相似文献
188.
In this paper, a full three-dimensional (3D) finite element Cosserat formulation is developed within the principles of continuum mechanics in the small deformation framework. The developed finite element formulation is general; however, the proposed constitutive laws incorporate the effect of the internal length parameter of 3D layered continua. The extension of the existing two-dimensional (2D) Cosserat formulation to the 3D framework is novel and is consistent with plate theory which can be considered as the 3D version of beam theory. The results demonstrate a high level of consistency with the analytical solutions predicted by plate theory as well as predictions by alternative numerical techniques such as the discrete element method. 相似文献
189.
Philippe J. Giabbanelli Azadeh Alimadad Vahid Dabbaghian Diane T. Finegood 《Journal of computational science》2012,3(1-2):17-27
The influence of social networks on the development of obesity has been demonstrated, and several models have been proposed. However, these models are limited since they consider obesity as a ‘contagious’ phenomenon that can be caught if most social contacts are deemed obese. Furthermore, social networks were proposed as a means to mitigate the obesity epidemic, but the interaction of social networks with environmental factors could not yet be explored as it was not accounted for in the current models. We propose a new model of obesity to face these limitations. In our model, individuals influence each other with respect to food intake and physical activity, which may lead to changes depending on the environment, and will impact energy balance and weight. We illustrate the potential of our model via two questions: could we focus on social networks and neglect environmental sources of influence, at least from a modelling viewpoint? Are some social structures less prone to be influenced by their environment? We performed a factorial analysis based on both synthetic and real-world social networks, and found that the environment was a key component behind changes in weight but its contribution was mitigated by structural properties of the population. Furthermore, the contribution of the environment was not dictated by macro-level properties (small-world and scale-free), which suggests that particular patterns of social ties at the micro-level are involved in making populations more resilient to change and less influenced by the environment. 相似文献