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排序方式: 共有141条查询结果,搜索用时 15 毫秒
101.
Mohammad Hosein Sayahi Saeed Bahadorikhalili Seyyed Jafar Saghanezhad Mohammad Mahdavi 《Research on Chemical Intermediates》2018,44(9):5241-5253
A novel copper (II) catalyst supported on polyethylenimine-functionalized magnetic graphene oxide (denoted Cu@PEI-MGO) has been developed and applied for the cyclization of benzylacetamide with 2-aminobenzamide to afford 2-arylquinazolin-4(3H)-ones in acetonitrile as an inexpensive, non-toxic and reusable solvent medium. Cu@PEI-MGO was characterized by transmission electron microscopy, scanning electron microscopy, thermo-gravimetric analysis, and Fourier-transform infra-red spectroscopy. 相似文献
102.
Entezari Hosein Almasi-Kashi Mohammad Alikhanzadeh-Arani Sima 《Journal of Cluster Science》2022,33(6):2689-2696
Journal of Cluster Science - Three EM wave absorbing (FeNi, CoNi, and FeCo)/ZnS nanocomposites were synthesized by simple and successful process. By comparison, it was demonstrated that the maximum... 相似文献
103.
Monolayer films from polystyrene asymmetric dimer colloidal particles were formed on a silicon substrate using a heat assisted vertical deposition technique. In dilute particle suspensions of systematically varied concentrations, the system maximizes the packing efficiency within a thin meniscus region. Structures with positional order and orientational order in and out of the substrate plane were observed in surface and cross-sectional scanning electron microscopy (SEM) images. The confining effect of the meniscus height drove the formation of the resulting oblique and hexagonal lattices with controlled orientation. The crystals exhibited features similar to the planes of the boron nitride and zinc sulfide atomic structures. The diffraction properties of both colloidal crystal structures were demonstrated via selected area diffraction for laser light in the visible region. 相似文献
104.
Reaction between Furan‐ or Thiophene‐2‐carbonyl Chloride,Isocyanides, and Dialkyl Acetylenedicarboxylates: Multicomponent Synthesis of 2,2′‐Bifurans and 2‐(Thiophen‐2‐yl)furans 下载免费PDF全文
Mohammad Hosein Sayahi Mehdi Adib Zeinab Hamooleh Long‐Guan Zhu Massoud Amanlou 《Helvetica chimica acta》2015,98(9):1231-1239
An efficient multi‐component synthesis of highly functionalized 2,2′‐bifurans and 2‐(thiophen‐2‐yl)furans is described. A mixture of furan‐ or thiophene‐2‐carbonyl chloride, an isocyanide, and a dialkyl acetylenedicarboxylate undergoes a smooth addition reaction in dry CH2Cl2 at ambient temperature to produce 2‐amino‐5‐(4‐chlorofuran‐2‐yl)furan‐3,4‐dicarboxylates and 2‐amino‐5‐(4‐chlorothiophen‐2‐yl)furan‐3,4‐dicarboxylates. A single‐crystal X‐ray‐analysis of a derivative conclusively confirms the structure of these 2,2′‐bifurans and 2‐(thiophen‐2‐yl)furans. A novel electrophilic aromatic substitution reaction can justify the formation of the Cl‐substituted furan or thiophene rings. 相似文献
105.
Leila Barangi Faramarz Afshar Taromi Hossein Nazockdast 《Macromolecular Symposia》2008,274(1):166-170
The in-situ compatibilization of PP/PA6 blend was studied in a twin screw extruder. The maleic anhydride (MA) content, peroxide concentration, shear rate and feeding order were among the variables investigated. Degree of grafting of samples collected prior to feeding of PA6 into the extruder was measured using titration combined with FTIR technique. From the SEM results it was found that the increasing of initial MA concentration led to larger PA particle size which could be related to secondary reactions between excess MA and PA. The melt linear viscoelastic measurements performed on the blend samples and the obtained relaxation time spectra showed shorter form relaxation time and interfacial relaxation time for one-step compatibilized sample compared to the sample prepared by the two-step method with the same degree of grafting. This was attributed to the stronger interfacial interaction of the one-step compatibilized blend samples which could be resulted from greater efficiency of grafting and/or compatibilization. These results were supported by SEM results which showed smaller particle size for the one-step compatibilized samples. It was demonstrated that melt linear viscoelastic measurement could provide a great insight into understanding the compatibilization process in twin screw extruder. 相似文献
106.
A constitutive model based on isotropic plasticity consideration ispresented in this work to model the thermo-mechanical behavior ofhigh-temperature shape memory alloys. In high-temperature shapememory alloys (HTSMAs), both martensitic transformation andrate-dependent plasticity (creep) occur simultaneously at hightemperatures. Furthermore, transformation-induced plasticity isanother deformation mechanism during martensitic transformation. Allthese phenomena are considered as dissipative processes to model themechanical behavior of HTSMAs in this study. The constitutive modelwas implemented for one-dimensional cases, and the results have beencompared with experimental data from thermal cycling test foractuator applications. 相似文献
107.
Baloutaki Bahram Ahmadi Sayahi Mohammad Hosein Nikpassand Mohammad Kefayati Hassan 《Research on Chemical Intermediates》2020,46(2):1153-1163
Research on Chemical Intermediates - New series of 2,4,6-triarylpyridines derivatives 5a–f and 6a–d were designed, synthesized and evaluated for their cytotoxic activity against breast... 相似文献
108.
A new magnetic metal–organic framework nanocomposite (CoFe2O4/TMU‐17‐NH2) was prepared via an embedding approach by synthesis of the metal–organic framework crystals in the presence of magnetic cobalt ferrite nanoparticles. We demonstrated that the resulting magnetic nanocomposite can serve as a recyclable nanocatalyst for one‐pot synthesis of bis‐3,4‐dihydropyrimidin‐2(1H)‐one and 3,4‐dihydropyrimidin‐2(1H)‐one derivatives via three‐component reaction of 1,3‐diketone, urea or thiourea and aromatic aldehyde under solvent‐free conditions. CoFe2O4/TMU‐17‐NH2 was characterized using various techniques. The recovery of the nanocomposite was achieved by a simple magnetic decantation and it was reused at least seven times without significant degradation in catalytic activity. 相似文献
109.
We consider a class of bilevel linear mixed-integer programs (BMIPs), where the follower’s optimization problem is a linear program. A typical assumption in the literature for BMIPs is that the follower responds to the leader optimally, i.e., the lower-level problem is solved to optimality for a given leader’s decision. However, this assumption may be violated in adversarial settings, where the follower may be willing to give up a portion of his/her optimal objective function value, and thus select a suboptimal solution, in order to inflict more damage to the leader. To handle such adversarial settings we consider a modeling approach referred to as \(\alpha \)-pessimistic BMIPs. The proposed method naturally encompasses as its special classes pessimistic BMIPs and max–min (or min–max) problems. Furthermore, we extend this new modeling approach by considering strong-weak bilevel programs, where the leader is not certain if the follower is collaborative or adversarial, and thus attempts to make a decision by taking into account both cases via a convex combination of the corresponding objective function values. We study basic properties of the proposed models and provide numerical examples with a class of the defender–attacker problems to illustrate the derived results. We also consider some related computational complexity issues, in particular, with respect to optimistic and pessimistic bilevel linear programs. 相似文献
110.