排序方式: 共有34条查询结果,搜索用时 15 毫秒
21.
Esmail Vessally Mohammad Reza Poorheravi Ladan Edjlali Maryam Motallebzadeh 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2014,88(7):1138-1141
Internal energy difference, ΔE s-t; enthalpy difference, ΔH s-t; Gibbs free energy difference, ΔG s-t, between the singlet (s) and triplet states (t) of XC5H5C, 1X (X = CH, N, P, and As) were computed at B3LYP/6-311++G** and MP2/6-311++G**//B3LYP/6-311++G** levels of theory. The ΔG s-t between the singlet and triplet states of 1 X were changed in the order: 1 P > 1 As > 1 N . 相似文献
22.
It is generally accepted that, in a laser cavity, the group delay--responsible for the round trip time--and the phase delay both have a linear dependence on the cavity length. We show that nanostructures, such as quantum wells, can create a coupling between phase and group velocities, resulting in a periodic dependence of the repetition rate on the laser cavity length. 相似文献
23.
Zhila Zare-Akbari Siavoush Dastmalchi Ladan Edjlali Leila Dinparast Moosa Es'haghi 《应用有机金属化学》2020,34(7):e5649
In this study, a novel, green, environmentally friendly and magnetically heterogeneous catalyst based on the immobilization of sulfosalicylic acid onto Fe3O4 nanoparticles (Fe3O4@sulfosalicylic acid MNPs) is reported. The bis-coumarin analogs were synthesized in high yield using the reaction of 1 equivalent of aryl aldehydes with 2 equivalents of 4-hydroxycoumarin in water under microwave irradiation conditions. Scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, thermogravimetric analysis, dynamic light scattering, vibrating sample magnetometry, Fourier transform infrared spectroscopy, UV–visible absorption, and Brunauer-Emmett-Teller (BET) techniques confirmed the successful synthesis of the catalyst. The main attractive characteristics of the presented green protocol are very short reaction times (10–15 min), excellent yields, and the avoidance of hazardous or toxic reagent and solvents. Thermal durability, easy separation, and high reusability are important advantages of the new catalyst in comparison to other catalysts. 相似文献
24.
Debashis Chanda Ladan E. Abolghasemi Peter R. Herman 《Applied Physics A: Materials Science & Processing》2008,93(1):33-37
Phase tunable multi-level diffractive optical elements define an attractive approach for single laser exposure fabrication
of 3-dimensional photonic crystal microstructures. The significant advantage of these multi-level diffractive optical elements
over two-level diffractive optical elements is the flexibility of fabricating a wide range of 3-dimensional periodic structures
by manipulating the relative phase of different diffracted beams. Here, phase tuning was applied to demonstrate fabrication
of a hybrid 3-dimensional structure intermediate between previously reported diamond-like Woodpile-type structure of tetragonal
symmetry and structure having body-centered-tetragonal lattice symmetry. Circularly polarized light was applied for the first
time to balance the diffraction order efficiencies and improve the structural uniformity. Design guidelines are presented
for generating diamond-like photonic crystal template that possesses complete photonic bandgap when inverted with high refractive
index materials. 相似文献
25.
Jalil Manafian Onur Alp Ilhan Ladan Avazpour As'ad Alizadeh 《Mathematical Methods in the Applied Sciences》2020,43(17):9904-9927
The present article deals with M-soliton solution and N-soliton solution of the (2 + 1)-dimensional asymmetrical Nizhnik–Novikov–Veselov equation by virtue of Hirota bilinear operator method. The obtained solutions for solving the current equation represent some localized waves including soliton, breather, lump, and their interactions, which have been investigated by the approach of the long-wave limit. Mainly, by choosing the specific parameter constraints in the M-soliton and N-soliton solutions, all cases of the one breather or one lump can be captured from the two, three, four, and five solitons. In addition, the performances of the mentioned technique, namely, the Hirota bilinear technique, are substantially powerful and absolutely reliable to search for new explicit solutions of nonlinear models. Meanwhile, the obtained solutions are extended with numerical simulation to analyze graphically, which results in localized waves and their interaction from the two-, three-, four-, and five-soliton solutions profiles. They will be extensively used to report many attractive physical phenomena in the fields of acoustics, heat transfer, fluid dynamics, classical mechanics, and so on. 相似文献
26.
Lida Fotouhi Ladan Behrozi Majid M. Heravi Davood Nematollahi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(10):2749-2757
The electrooxidation of catechols (1a–d) in the presence of pyrimidine-2-thiol (3) as a nucleophile in aqueous solution is described. The mechanistic investigations using cyclic voltammetry and controlled potential coulometry indicate that the quinone derived from catechols participates in a Michael addition reaction with pyrimidine-2-thiol to form corresponding catechol derivatives of 6a–d (ECEC). The efficient electrosynthesis of 6a–d has been performed at carbon rod electrodes in an undivided cell in good yield and purity. 相似文献
27.
The bactericidal activity of a deuteroporphyrin-hemin mixture on gram-positive bacteria. A microbiological and spectroscopic study 总被引:1,自引:0,他引:1
Z Malik H Ladan Y Nitzan B Ehrenberg 《Journal of photochemistry and photobiology. B, Biology》1990,6(4):419-430
The combined antibacterial activity of various porphyrins with hemin on Gram-positive bacteria was studied. Protoporphyrin, hematoporphyrin derivative and deuteroporphyrin show only a marginal inhibitory effect in the dark. However, hemin has a strong cytotoxic effect which is independent of illumination and is equally strong in the dark. The disadvantage of hemin treatment is that it is temporary. In this study, we have demonstrated that a combination of deuteroporphyrin and hemin has a unique cytotoxic activity on Staphylococcus aureus, Streptococcus faecalis and Bacillus cereus. The effect of the combined compound is stronger than that of the separate constituents, and is as strong in the dark as in the light. Only 0.005% of the initial S. aureus population survive after a 2 h treatment. Absorption and fluorescence spectra of hemin-deuteroporphyrin mixtures in water and liposomes suggest the formation of a species with spectroscopic properties which are different from those of the two constituents. 相似文献
28.
29.
Vision is generally considered the dominant sensory modality; self-contained and independent of other senses. In this article, we will present recent results that contradict this view, and show that visual perception can be strongly altered by sound and touch, and such alterations can occur even at early stages of processing, as early as primary visual cortex. We will first review the behavioral evidence demonstrating modulation of visual perception by other modalities. As extreme examples of such modulations, we will describe two visual illusions induced by sound, and a visual illusion induced by touch. Next, we will discuss studies demonstrating modulation of activity in visual areas by stimulation of other modalities, and discuss possible pathways that could underpin such interactions. This will be followed by a discussion of how crossmodal interactions can affect visual learning and adaptation. We will review several studies showing crossmodal effects on visual learning. We will conclude with a discussion of computational principles governing these crossmodal interactions, and review several recent studies that demonstrate that these interactions are statistically optimal. 相似文献
30.
The study reported here was undertaken because recent research on nucleate boiling has implicated vapor entrainment by drops as a mechanism for vapor bubble nucleation. The mechanism has been called secondary nucleation. The purpose of this research was to determine the behavior of entrained air bubbles when a drop of liquid strikes a liquid surface. A liquid drop striking the surface of a pool of the same liquid was found usually to entrain large numbers of small air bubbles. Some of these bubbles are frequently carried rapidly deep into the pool by a vortex ring but many can be deposited in a trail or left floating on the surface. Air bubble entrainment was observed with water and several organic liquids and some differences were noted. Drops with diameters from 200 μm to 4 mm were studied. Sometimes hundreds of bubbles were entrained some with diameters up to 100 μm. These results lend support to the secondary nucleation hypothesis and indicate further research on vapor bubble entrainment under conditions more typical of boiling would be appropriate. 相似文献