排序方式: 共有83条查询结果,搜索用时 62 毫秒
1.
2.
We present novel inorganic–organic hybrid catalyst to accomplish domino multi‐component reaction (MCR) for synthesis of 3‐amino‐2′‐oxospiro[benzo[c]pyrano[3,2‐a]phenazine‐1,3′‐indoline]‐2‐carbonitrile/carboxylate derivatives. This methodology offers remarkable development by easy production of H3PMo12O40/Hyd‐SBA‐15 in regard to solving the problem of using harsh catalysts, also it demonstrates to be impressive and environmentally friendly in term of low reaction times and high yields. 相似文献
3.
Synergetic catalytic effect of rGO,Pd, Fe3O4 and PPy as a magnetically separable and recyclable nanocomposite for coupling reactions in green media
下载免费PDF全文
![点击此处可从《应用有机金属化学》网站下载免费的PDF全文](/ch/ext_images/free.gif)
In this paper, rGO/Pd–Fe3O4@PPy as an efficient stable nanocomposite was synthesized. To understand the synergetic effects of rGO, Pd, Fe3O4 and PolyPyrrole, the performance of rGO/Pd–Fe3O4@PPy as a heterogeneous recyclable nanocatalyst in the green synthesis of C‐C and C‐O coupling products, as well as different conditions are studied. Synthesized rGO/Pd–Fe3O4@PPy was characterized by FT‐IR, XRD, FE‐SEM, EDS, TGA and AFM analysis. Best results are obtained under sonication in H2O for C‐C coupling and by ball‐milling for C‐O coupling. The benefits of this method include: green solvents and conditions, absence of external base, low reaction times with high yield and easy work‐up method. 相似文献
4.
Microstructure of nickel nanoparticles embedded in carbon films: case study on annealing effect by micromorphology analysis
下载免费PDF全文
![点击此处可从《Surface and interface analysis : SIA》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Ştefan Ţălu Miroslaw Bramowicz Slawomir Kulesza Azizollah Shafiekhani Maryam Rahmati Atefeh Ghaderi Mohammad Ahmadirad Shahram Solaymani 《Surface and interface analysis : SIA》2017,49(3):153-160
The presented study is aimed at analyzing the surface texture of amorphous hydrogenated carbon layers containing nickel nanoparticles (Ni‐NPs@a‐C:H) within their structure, which were deposited by Radio Frequency (RF) sputtering and RF‐Plasma Enhanced Chemical Vapor Deposition (RF‐PECVD) methods on glass substrates. Prepared films were then used as research material following their annealing at two different temperatures of 250 °C and 350 °C in an inert argon atmosphere. Series of height samples were taken with the help of atomic force microscopy (AFM) operating in a non‐contact mode and examined in order to determine their fractal characteristics. Raw AFM data were first plane‐fitted to remove the surface bow exhibiting the so‐called residual surface, and then numerically processed to calculate the Areal Autocorrelation Function (AACF), which was later used to compute the Structure Function (SF). The log–log plots of the latter served for calculation of fractal properties of surfaces under investigation, including fractal dimension D, and pseudo‐topothesy K. The analysis of 3‐D surface texture helps to understand their essential characteristics and their implications as well as graphical models and their implementation in computer simulation. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
5.
An efficient ionic liquid with both Brønsted acidic and Lewis basic sites, namely 1,4-dimethyl-1-(4-sulphobutyl)piperazinium hydrogen sulphate (IL1), was synthesised and characterised. IL1 is a “green”, homogeneous and reusable catalyst for: i) the synthesis of pyranopyrazoles (Va-Vj)and benzopyrans (VIa-VIj and VIIa-VIIf) at ambient temperature under solvent-free conditions and ii) the synthesis of amino-2-chromenes (VIIIa-VIIIi and IXa-IXi) and dihyropyrano[c]chromenes (Xa-Xi) at 80 °C under solvent-free conditions. The reactions were rapid with excellent product yields. In addition, the double Brønsted acid, 1,4-dimethyl-1,4-bis(4-sulphobutyl)piperazinium hydrogen sulphate (IL2), was prepared to evaluate the cooperation efficiency of their Brønsted acidic and Lewis basic sites as compared with the double Brønsted acidic sites in IL1. 相似文献
6.
Efficient removal of hexavalent chromium and lead from aqueous solutions by s‐triazine containing nanoporous polyamide
下载免费PDF全文
![点击此处可从《先进技术聚合物》网站下载免费的PDF全文](/ch/ext_images/free.gif)
s‐Triazine containing dicarboxylic acid was synthesized. Then, it was reacted with 1,3‐phenylenediamine in molten tetrabutylammonium bromide to formed soluble aromatic polyamide with good yield and moderate inherent viscosity of 0.35 dL g?1. The solubility and flexibility of polyamides are low. So, we used ether group such as di(4‐aminephenyl) ether in building polyamide. The structure of monomer and polymer was confirmed by Fourier transform infrared spectroscopy, elemental analysis, and proton nuclear magnetic resonance techniques. Thermogravimetric analysis was used to evaluate the thermal properties of synthesized polyamide, and their results show that this polymer had a good thermal stability. The surface morphology of s‐triazine containing polyamide was studied by field emission‐scanning electron microscopy and transmission electron microscopy, and the results show that it has a porous morphology and moderate Brunauer–Emmett–Teller specific surface (367 m2 g?1). It was further investigated for Pb (II) and Cr(VI) ion removal by optimizing the parameters including pH and contact time. The maximum uptakes of Pb(II) and Cr(VI) at pH 5.0 and pH 4.0 are 57% and 76%, respectively. Also, sorption kinetics of this polymer was investigated. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
7.
Direct mechanical force is used to create a temporary shape in shape memory polymers. This can become difficult in situations where the sample is not directly accessible such as interior in the body. In these cases it is not possible to use a direct mechanical force to deform the sample into temporary shape; therefore other alternative routes should be proposed. The magnetic force is a good candidate for inducing remote deformation. The ability of magnetic field to cause deformation in soft matters has already been revealed. To prove the hypothesis of using magnetic force to create temporary shape, magnetic field active shape memory polymeric nanocomposites were manufactured by incorporation of NdFeB ferromagnetic micro particles in a nanocomposite based on crosslinked low density polyethylene loaded with 2 wt.% of organoclay. The results indicate that as the NdFeB content increases, the reversible temporary deformation induced in the samples by the magnetic force increases. The effect of NdFeB concentration on the shape recovery progress and the possibility of heat induction in NdFeB filled samples through the application of an alternating magnetic field were also examined. 相似文献
8.
Reactions of SnCl2 with the complexes cis‐[PtCl2(P2)] (P2=dppf (1,1′‐bis(diphenylphosphino)ferrocene), dppp (1,3‐bis(diphenylphosphino)propane=1,1′‐(propane‐1,3‐diyl)bis[1,1‐diphenylphosphine]), dppb (1,4‐bis(diphenylphosphino)butane=1,1′‐(butane‐1,4‐diyl)bis[1,1‐diphenylphosphine]), and dpppe (1,5‐bis(diphenylphosphino)pentane=1,1′‐(pentane‐1,5‐diyl)bis[1,1‐diphenylphosphine])) resulted in the insertion of SnCl2 into the Pt? Cl bond to afford the cis‐[PtCl(SnCl3)(P2)] complexes. However, the reaction of the complexes cis‐[PtCl2(P2)] (P2=dppf, dppm (bis(diphenylphosphino)methane=1,1′‐methylenebis[1,1‐diphenylphosphine]), dppe (1,2‐bis(diphenylphosphino)ethane=1,1′‐(ethane‐1,2‐diyl)bis[1,1‐diphenylphosphine]), dppp, dppb, and dpppe; P=Ph3P and (MeO)3P) with SnX2 (X=Br or I) resulted in the halogen exchange to yield the complexes [PtX2(P2)]. In contrast, treatment of cis‐[PtBr2(dppm)] with SnBr2 resulted in the insertion of SnBr2 into the Pt? Br bond to form cis‐[Pt(SnBr3)2(dppm)], and this product was in equilibrium with the starting complex cis‐[PtBr2(dppm)]. Moreover, the reaction of cis‐[PtCl2(dppb)] with a mixture SnCl2/SnI2 in a 2 : 1 mol ratio resulted in the formation of cis‐[PtI2(dppb)] as a consequence of the selective halogen‐exchange reaction. 31P‐NMR Data for all complexes are reported, and a correlation between the chemical shifts and the coupling constants was established for mono‐ and bis(trichlorostannyl)platinum complexes. The effect of the alkane chain length of the ligand and SnII halide is described. 相似文献
9.
Atefeh Ashouri Saeed Mahdavifar Grégoire Misguich Javad Vahedi 《Annalen der Physik》2020,532(8):1900515
There has been some substantial research about the connections between quantum chaos and quantum correlations in many-body systems. This paper discusses a specific aspect of correlations in chaotic spin models, through concurrence (CC) and quantum discord (QD). Numerical results obtained in the quantum chaos regime and in the integrable regime of spin-1/2 chains are compared. The CC and QD between nearest-neighbor pairs of spins are calculated for all energy eigenstates. The results show that, depending on whether the system is in a chaotic or integrable regime, the distribution of CC and QD are markedly different. On the other hand, in the integrable regime, states with the largest CC and QD are found in the middle of the spectrum, in the chaotic regime, the states with the strongest correlations are found at low and high energies at the edges of spectrum. Finite-size effects are analyzed, and some of the results are discussed in the light of the eigenstate thermalization hypothesis. 相似文献
10.
Nonlinear Dynamics - This paper discusses averaging and vibrational control of mechanical control-affine systems with piecewise linear damping and high-frequency inputs. The results are used for... 相似文献