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51.
Salamin YI 《Optics letters》2007,32(1):90-92
Fields of a radially polarized laser beam developed recently [Y. I. Salamin, Opt. Lett.31, 2619 (2006)] are employed to show that electrons produced by atomic ionization near the focus may be accelerated to GeV energies. Conditions for producing a mono-energetic and well-collimated electron beam are discussed. 相似文献
52.
Novel thiono and seleno phosphoramidate compounds with the general formula (X)(Y)P(C6H5)2; (X = NMe2 & Y = S, 1a; X = NEt2 & Y = S, 2a; X = NMe(CH2Ph) & Y = S, 3a; X = NH(CH2Ph) & Y = S, 4a; X = NEt(CH2Ph) & Y = S, 5a; X = N(C(Me)3) (CH2Ph) & Y = S, 6a; X = N(CH2Ph)2 & Y = S, 7a; X = NMe2 & Y = Se, 1b; X = NEt2 & Y = Se, 2b; X = NMe(CH2Ph) & Y = Se, 3b; X = NH (CH2Ph) & Y = Se, 4b; X = NEt(CH2Ph) & Y = Se, 5b; X = N(C(Me)3)(CH2Ph) & Y = Se, 6b and X = N(CH2Ph)2 & Y = Se, 7b) were prepared and characterized by 1H, 31P and 13C NMR and IR spectroscopy and elemental analysis. 31P chemical shift of thiono and seleno derivatives didn’t show significant different because of their little difference in
electronegativity sulfur and selenium. Hydrophobic parameter of compounds was determined by measurement of octanol-water partition
coefficient by shake-flask technique. Determination of human erythrocyte acetylcholinesterase (hAChE) activity was carried
out according to the Ellman’s modified kinetic method. IC50 values of the selected thiono and seleno compounds varied from 3.4 to 0.11 and 9.9 to 5.1 mM, respectively. The seleno compounds
show lower affinities for hAChE relative to the thino compounds. These results demonstrate that hydrophobic and electronic
factors of the organophosphorus compounds play a key role on the inhibitory potency. 相似文献
53.
In this work a facile hydrothermal route has been employed to prepare a multiwall carbon nanotube wrapped in a chelating resin. 8-Hydroxyquinoline and p-formaldehyde were used as monomer and linker for polymer synthesis. The prepared composite was employed as an efficient adsorbent for lead adsorption and preconcentration from various matrices. Effective parameters on lead adsorption have been optimized by central composite design. Results showed that equilibrium adsorption was obtained at pH = 4, with a shacking time of 15 min and adsorbent dosage of 15 mg. Isotherm study showed that the sorbent has adsorbent capacity of 250 mg g?1; moreover, the process followed a Langmuir isotherm model. Thermodynamic investigation confirmed that lead adsorption is spontaneous, as well as follows endothermic path. 相似文献
54.
In this work, two novel chemosensors based on calix[4]arene bearing (thio)barbituric acid groups (BC1 and BC2) were synthesised, and their structures were characterised by HRMS, NMR and FTIR. Furthermore, their binding properties towards various biologically relevant metal ions were studied by fluorescence titrations, 1H NMR spectroscopies and Job’s plot evaluations. The chemosensor BC1 displayed excellent binding affinity and selectivity towards Cu2+, which was characterised using fluorescence spectroscopy. On the other hand, BC2 exhibited a very remarkable fluorescence enhancement as well as visible colour change from pale green to sunset yellow, in presence of Hg2+ ions. Finally, Job’s plot method revealed 1:1 binding stoichiometry for both BC1:Cu2+ complex and BC2:Hg2+ complex. 相似文献
55.
Ultrasonic welding (USW) is an alternative solution for the bonding process especially in automotive industry. Ultrasonic welding of metals is a joining technique as a combination of applying pressure and frictional vibrations within the range of ultrasonic frequencies. In automotive industry, ultrasonic welding is often used for wired connections. As an alternative for crimping technology of multi-strand aluminum cables in wire bonding, ultrasonic welding is used. This work presents a thermomechanical analysis of the interface between two mating parts in USW. For this reason, the temperature distribution at bonding locations inside a wire bundle due to frictional vibrations and pressure is investigated using the finite element method (FEM). The obvious difference in microsections from different welding samples, which originates from different local temperature rises, was the motivation for this study to further investigate the thermomechanical aspects of the USW by use of finite element simulations. (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
56.
57.
Seyyed Mojtaba Mousavi Seyyed Alireza Hashemi Masoomeh Yari Kalashgrani Ahmad Gholami Yousef Mazaheri Mohsen Riazi Darwin Kurniawan Mohammad Arjmand O. Madkhali Mahmood D. Aljabri Mohammed M. Rahman Wei-Hung Chiang 《Chemical record (New York, N.Y.)》2024,24(1):e202200266
The ever-growing demand of human society for clean and reliable energy sources spurred a substantial academic interest in exploring the potential of biological resources for developing energy generation and storage systems. As a result, alternative energy sources are needed in populous developing countries to compensate for energy deficits in an environmentally sustainable manner. This review aims to evaluate and summarize the recent progress in bio-based polymer composites (PCs) for energy generation and storage. The articulated review provides an overview of energy storage systems, e. g., supercapacitors and batteries, and discusses the future possibilities of various solar cells (SCs), using both past research progress and possible future developments as a basis for discussion. These studies examine systematic and sequential advances in different generations of SCs. Developing novel PCs that are efficient, stable, and cost-effective is of utmost importance. In addition, the current state of high-performance equipment for each of the technologies is evaluated in detail. We also discuss the prospects, future trends, and opportunities regarding using bioresources for energy generation and storage, as well as the development of low-cost and efficient PCs for SCs. 相似文献
58.
59.
M.T. Darvishi S. Kheybari F. Khani 《Communications in Nonlinear Science & Numerical Simulation》2008,13(10):2091-2103
In this paper, a numerical solution of the generalized Burgers–Huxley equation is presented. This is the application of spectral collocation method. To reduce roundoff error in this method we use Darvishi’s preconditionings. The numerical results obtained by this method have been compared with the exact solution. It can be seen that they are in a good agreement with each other, because errors are very small and figures of exact and numerical solutions are very similar. 相似文献
60.
A total cover of a graph G is a subset of V(G)E(G) which covers all elements of V(G)E(G). The total covering number 2(G) of a graph G is the minimum cardinality of a total cover in G. In [1], it is proven that 2(G)[n/2] for a connected graph G of order n. Here we consider the extremal case and give some properties of connected graphs which have a total covering number [n/2]. We prove that such a graph with even order has a 1-factor and such a graph with odd order is factor-critical. 相似文献