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81.
An Isocyanide‐Based Multicomponent Reaction: New Route for Synthesis of Isoxazolinedione Derivatives
Azizollah Habibi Fahimeh Vafadarnejad Marjan Akbari Armand 《Journal of heterocyclic chemistry》2013,50(4):887-890
An efficient and novel multicomponent reaction for synthesis of new isoxazolinedione has been described. This protocol involves reaction of two molecules of isocyanide, aliphatic oxime, alkylidene substituted Meldrum's acid, and water (moisture). Elemental analyses, IR, 1H NMR, and 13C NMR spectroscopic data of products are consistent with the structure defined by X‐ray diffraction analysis. 相似文献
82.
A new, facile, and cost-effective process involving the solvent-free synthesis of amidoalkyl naphthols using a three-component, one-pot condensation reaction of β-naphthol, aromatic aldehyde, and amides in the presence of Al(H2PO4)3 as heterogeneous catalyst under thermal conditions and microwave irradiation has been described. This new approach has the advantage of consistently excellent yields and short reaction times. The catalyst has shown a very stable catalytic activity in the reaction conditions and also can be recovered and recycled. 相似文献
83.
Hamid Reza Shaterian Fahimeh Khorami Azita Amirzadeh Majid Ghashang 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):2865-2874
A highly efficient and mild procedure for the trimethylsilylation of a wide variety of alcohols, including primary, benzylic, secondary, hindered secondary, tertiary, phenols, and oximes with hexamethyldisilazane (HMDS) using alumina perchloric acid (Al 2 O 3 -HClO 4 ) as recyclable heterogeneous catalyst in excellent yields with short reaction times (3?65 min) under ambient conditions is described. 相似文献
84.
Ebrahimzadeh H Saharkhiz Z Tavassoli M Kamarei F Asgharinezhad AA 《Journal of separation science》2011,34(11):1275-1282
Ultrasound-assisted emulsification microextraction based on the solidification of floating organic droplet combined with high-performance liquid chromatography-ultra violet (HPLC-UV) detection was applied for the extraction and determination of fluoxetine, citalopram, and venlafaxine as antidepressants drugs in biological samples. In total, 30 μL of undecanol was injected slowly into a glass-centrifuge tube containing 5 mL alkaline sample solution that was located inside the ultrasonic water bath. The formed emulsion was centrifuged and the fine droplets of solvent were floated at the top of the test tube. The test tube was then cooled in an ice bath and the solidified solvent transferred into a conical vial; it melted quickly at room temperature. Then the analysis of the extracts was carried out by high-performance liquid chromatography. Under optimal conditions, the preconcentration factors were between 174 and 316. Detection limits (LODs) of 3 μg/L were obtained and the calibration graphs were linear within the range of 10-1000 μg/L. Finally, the feasibility of the proposed method was successfully confirmed by extraction and determination of the antidepressant drugs in human urine and plasma samples in the range of microgram per liter and suitable results were obtained. 相似文献
85.
Ultrasound-assisted emulsification microextraction with solidification of floating organic droplet (USAEME-SFO) followed by high performance liquid chromatography-diode array detection (HPLC-DAD), was applied for preconcentration and determination of phthalate esters in cosmetic and water samples. The effects of different variables on the extraction efficiency were studied simultaneously using an experimental design. The variables of interest in the USAEME-SFO were extraction solvent volume, salt effect, extraction time and centrifugation time. A factorial experimental design was employed for screening to determine the variables significantly affecting the extraction efficiency. Then, the significant factors were optimized by using a Box-Behnken design (BBD) and the response surface equations were derived. The optimum experimental conditions were extraction solvent volume, 30 μL; sodium chloride concentration, 20% (w/v); extraction time, 12 min and centrifugation time, 5 min. Under optimal conditions, the preconcentration factors were between 355 and 409. The limit of detections (LODs) ranged from 0.005 μg L−1 (for Diethylphthalate) to 0.01 μg L−1 (for Dimethylphthalate). Dynamic linear ranges; (DLRs) of 0.05-800 and 0.05-1000 μg L−1 were obtained for Diisobutyl- and Dimethylphthalate, respectively. The performance of the method was evaluated for extraction and determination of phthalate esters in cosmetic and environmental water samples in micrograms per liter and satisfactory results were obtained (RSDs < 12.6%). 相似文献
86.
Fahimeh Biglari Malik Abu HassanWah June Leong 《Journal of Computational and Applied Mathematics》2011,235(8):2412-2422
Many researches attempt to improve the efficiency of the usual quasi-Newton (QN) methods by accelerating the performance of the algorithm without causing more storage demand. They aim to employ more available information from the function values and gradient to approximate the curvature of the objective function. In this paper we derive a new QN method of this type using a fourth order tensor model and show that it is superior with respect to the prior modification of Wei et al. (2006) [4]. Convergence analysis gives the local convergence property of this method and numerical results show the advantage of the modified QN method. 相似文献
87.
88.
Sajjad Aslani Khiavi Hamid Khaloozadeh Fahimeh Soltanian 《Mathematical and Computer Modelling of Dynamical Systems: Methods, Tools and Applications in Engineering and Related Sciences》2013,19(5):499-521
ABSTRACTWe study four-echelon supply chains consisting of manufacturer, wholesaler, retailer and customer with recovery center as hybrid recycling channels. In order to gain a larger market share, the retailer often takes the sales as a decision-making variable. For this purpose, in this supply chain, the retailer limits the forecast of market demand in future periods with expected logic. It also manages demand by leveraging prices and choosing market. In this paper, first, we investigate the state-space model of this supply chain system and examine the effect of complex dynamic and stochastic noise on the bullwhip effect. We analytically prove that this factor leads to the bullwhip effect. So, first, we filtered the information between nodes with extended Kalman filter after which we regulated the destructive effects of the bullwhip phenomenon by designing a non-linear quadratic Gaussian optimal controller. Eventually, the simulation results indicate the efficiency of the proposed method. 相似文献
89.
Damping in a Squeezed Bath and Its Time Evolution through the Complete Class of Gaussian Quasi-Distributions
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By virtue of the thermo-entangled states representation of the density operator and using the dissipative interaction picture, we solve the master equation of a driven damped harmonic oscillator in a squeezed bath. We show that the essential part of the dynamics can be expressed by the convolution of the initial Wigner function with a special kind of normalized Gaussian in the phase space and relate the dynamics with the change of Gaussian ordering of the density operator. 相似文献
90.
Molecular Diversity - Structurally diverse benzo[g]chromenes were conveniently synthesized by one-pot, multi-component reaction of N-alkyl-1-(methylthio)-2-nitroethenamine (derived from the... 相似文献