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71.
Isoquinoline reacts with diaroylacetylenes in the presence of 1,3-dicarbonyl compounds in a one-pot reaction to afford functionalized spiropyrroloisoquinolines in 90-96% yields. 相似文献
72.
73.
One‐Pot Synthesis of Novel Pyrrolo[1,2‐a]quinoxaline‐4(5H)‐ones Using Benzene‐1,2‐diamine,Acetylenedicarboxylates, and β‐Nitrostyrene Derivatives 下载免费PDF全文
The reaction between a variety of o‐phenylenediamines (=benzene‐1,2‐diamines), dialkyl acetylenedicarboxylates, and derivatives of nitrostyrene (=(E)‐(2‐nitroethenyl)benzene) in the presence of sulfamic acid (SA; H3NSO3) as catalyst led to the corresponding pyrrolo[1,2‐a]quinoxaline‐4(5H)‐one derivatives in high yields. 相似文献
74.
Afshin Moradi 《理论物理通讯》2015,64(5):571-575
The dispersion properties of high- and low-frequency electrostatic oscillations of a spherical metallic plasma consisting of hot electrons and cold ions are investigated. The main interest and the key first applications of this system are the spherical metal nanoparticles. General expressions of dispersion relations are obtained for the so-called surface and bulk plasmon waves, and surface and bulk ion-acoustic waves in spherical geometry, using hydrodynamic equations and Poisson equation with appropriate boundary conditions. Numerical results show that dispersion effects become large for metallic particles of small radii, particularly in the range of few nanometers. 相似文献
75.
Three reusable and durable superhydrophobic nanofibrous filters were prepared by dip coating the nanofibrous fabric in the three different dispersed solutions of the newly modified nanoparticles (ZnO‐NSPO, AlOO‐NSPO, and titanium dioxide [TiO2]‐NSPO). The contact angle results proved that the TiO2‐NSPO coated nanofibrous polyacrylonitrile (PAN) filter was hydrophobic with the water contact angle (WCA) of 141° while the ZnO‐NSPO and AlOO‐NSPO coated nanofibrous PAN filters were superhydrophobic with the WCA of 168° and 152°, respectively. The as‐prepared filters can be utilized as an effective martial for oil‐water separation with separation efficiency of over 98%. 相似文献
76.
Iman Jafari Mohamadreza Shakiba Fatemeh Khosravi Seeram Ramakrishna Ehsan Abasi Ying Shen Teo Mohammadreza Kalaee Majid Abdouss Ahmad Ramazani S. A Omid Moradi Erfan Rezvani Ghomi 《Molecules (Basel, Switzerland)》2021,26(6)
The incorporation of nanofillers such as graphene into polymers has shown significant improvements in mechanical characteristics, thermal stability, and conductivity of resulting polymeric nanocomposites. To this aim, the influence of incorporation of graphene nanosheets into ultra-high molecular weight polyethylene (UHMWPE) on the thermal behavior and degradation kinetics of UHMWPE/graphene nanocomposites was investigated. Scanning electron microscopy (SEM) analysis revealed that graphene nanosheets were uniformly spread throughout the UHMWPE’s molecular chains. X-Ray Diffraction (XRD) data posited that the morphology of dispersed graphene sheets in UHMWPE was exfoliated. Non-isothermal differential scanning calorimetry (DSC) studies identified a more pronounced increase in melting temperatures and latent heat of fusions in nanocomposites compared to UHMWPE at lower concentrations of graphene. Thermogravimetric analysis (TGA) and derivative thermogravimetric (DTG) revealed that UHMWPE’s thermal stability has been improved via incorporating graphene nanosheets. Further, degradation kinetics of neat polymer and nanocomposites have been modeled using equations such as Friedman, Ozawa–Flynn–Wall (OFW), Kissinger, and Augis and Bennett’s. The "Model-Fitting Method” showed that the auto-catalytic nth-order mechanism provided a highly consistent and appropriate fit to describe the degradation mechanism of UHMWPE and its graphene nanocomposites. In addition, the calculated activation energy (Ea) of thermal degradation was enhanced by an increase in graphene concentration up to 2.1 wt.%, followed by a decrease in higher graphene content. 相似文献
77.
Behrooz Ranjbarfar Saeed Taghvaei Ganjali Mir Mohammad Alavi Nikje Shahram Moradi 《Russian Journal of Applied Chemistry》2018,91(7):1198-1208
Novel water-based biodegradable polyurethane dispersions with an aim to develop environmentally friendly materials, including medicine, various industries, have been prepared in this study. Biodegradable ionic polyurethanes (IPU) were synthesized based on polyols from renewable resources, such as castor oil (CO), in the presence of a polyester polyol and polyethylene glycol (PEG) with hydrophilic property and 1,6-hexamethylene diisocyanate. 1,4-Butanediol and dibutyltin dilaurate, were used as a chain extender and catalyst, respectively. The comprehensive investigations of the structure and properties of five types of synthesized polyurethanes demonstrated biodegradability relationship of these polyurethanes with their structure and composition. In this research effects of different types and content of polyols on biodegradability and physico mechanical properties of prepared PUDs were investigated. The structure, properties and physico mechanical and application behavior of mentioned materials were characterized by 1H NMR, FTIR spectroscopy, thermogravimetric analysis (TG/DTG) and dynamic mechanical thermal analysis (DMTA). The adhesion properties were measured by pull off test as well. Particle size was measured by dynamic light scattering (DLS) methods. The biodegradability of prepared polyurethane dispersions was confirmed by water uptake, hydrolytic and enzymatic degradation in phosphate buffer saline (PBS) with lipase enzyme in PBS. Results showed that by the incorporation of natural components into the polymer chain, adjusting of hydrophilic and hydrolytic liability properties of soft segments and especial relevant designs, useful polyurethane can be synthesized with desirable property of biodegradability and dispersion stability. Except for one sample, other samples were decomposed totally in enzymatic media. 相似文献
78.
Production of fibroin nanopowder through electrospraying 总被引:1,自引:0,他引:1
Fibroin is a biomaterial and in the powder form, has found applications such as food and cosmetic additive as well as drug
delivery. Various methods have been employed to produce fibroin powder with different particle size range. In this study,
a novel and original application of electrospraying technique capable of producing fibroin nanopowder is presented. Our technique
is based on electrospraying of dilute fibroin solution in formic acid. Moreover, the effect of variables in electrospraying,
namely, concentration of fibroin solution, voltage, feed rate, and needle–collector distance, on average particle size of
fibroin nanopowder has been studied. The result of this study showed that electrospraying is capable of producing fibroin
nanopowder with average particle size as low as 80 nm. In fact in comparison to other methods reported in the literature,
electrospraying alongside with the precipitation method produce fibroin nanopowder with the lowest particle size. However,
nanopowder obtained through electrospraying technique enjoys a more uniform spherical shape and size. As far as the variables
are concerned, it was ascertained that lower concentrations, lower feed rates and longer needle–collector distances lead to
a decrease in the average particle size of fibroin nanopowder. Increasing voltage up to 20 kV decreases the particle size;
but with higher voltages the average particle size increases. FT-IR and XRD studies showed that the fibroin nanopowder has
a β-sheets structure, similar to fibroin filaments but with a lower crystallinity index. 相似文献
79.
Afshin Moradi 《Photonics and Nanostructures》2013,11(1):85-88
Propagation of surface plasmon–polariton modes in metallic single-walled carbon nanotubes is investigated within the framework of the classical electrodynamics. Electronic excitations on the nanotube's surface are modeled by an infinitesimally thin layer of free-electron gas which is described by means of the linearized hydrodynamic theory. General expression of surface modes dispersion is obtained by solving Maxwell and hydrodynamic equations with appropriate boundary conditions. It is shown that the system generally disallows the separation of the transverse electric (TE) modes and transverse magnetic (TM) modes, except for the case of modes with no angular dependence. 相似文献
80.
Hydrogen peroxide/MoO3, as an efficient and clean oxidizing system was used to afford diasteroselective oxidative cyclization of bisnaphthols to spirans in ethanol at 60 °C with high yields. Bisnaphthols were prepared by the reaction of a series of aldehydes and 2-naphthol in the presence of a catalytic amount of H3[P(Mo3O10)4].nH2O (HPa) in refluxing dichloromethane. 相似文献