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91.
We calculate level densities for 56,57 Fe nuclei using BCS hamiltonian with inclusion of pairing interaction.The results of calculations show that the step structure observed experimentally has been supported by microscopic theory. Also the S-shaped energy and entropy as function of temperature have been obtained in theoretical calculations.Structures in the curves are interpreted as fingerprints of breaking Cooper pairs and quenching of pairing correlations. 相似文献
92.
Ali Ebrahimi Sayyed Mostafa Habibi Khorassani Shiva Rezazadeh Abolfazl Azizi Pouya Karimi 《Molecular physics》2014,112(1):41-48
The mutual influence of cation–π and anion–π interactions in the π–Mz+–π–X?–π system (Mz+ = Li+, Na+, K+, Be2+, Mg2+, Ca2+ and X? = F?, Cl?) has been studied by quantum mechanical calculations. Both geometric parameters and energy data reveal that cation–π and anion–π interactions enhance each other in the π–Mz+–π–X?–π system. Individual binding energies (Eion···π) have been estimated in the quintuplet system using a simple new method from electron charge densities calculated at the bond critical points (BCPs) of the ion···π interaction by the atoms in molecules (AIM) method at the M062X/6-31+G(d) level of theory. With respect to the obtained individual binding energies, the strength of an ion···π interaction depends on the cooperative effects of other components. 相似文献
93.
Ali Ebrahimi Pouya Karimi Farideh Badichi Akher Roya Behazin Najmeh Mostafavi 《Molecular physics》2014,112(7):1047-1056
Stability of the π–π stacking interactions in the ben∥substituted-ben and ben∥substituted-COT complexes was studied using the computational quantum chemistry methods (where ben and COT are benzene and cyclooctatetraene, ∥ denotes π–π stacking interaction, substituted-ben and substituted-COT are benzene and cyclooctatetraene which substituted with four ethynyl-X groups, respectively, and X = OH, CH3, H, F, CF3, CN and NO2). In these complexes electron-withdrawing substituents lead to larger binding energies and electron-donating ones lead to weaker interactions compared to X = H. There are meaningful correlations between the Hammett constants and binding energies. The atoms in molecules (AIM) analysis shows that formation of these complexes is accompanied by increase in the electron charge densities at the ring critical points of the substituted-ben and substituted-COT rings which leads to increase/decrease of the π–π stacking interactions in the ben∥substituted-ben/ben∥substituted-COT complexes. The charge transfer occurs from benzene to substituted-ben in the ben∥substituted-ben complexes and from substituted-COT to benzene (with the exception of X = CN) in the ben∥substituted-COT ones. Nuclear magnetic resonance calculations demonstrate that interactions of the more aromatic substituted-ben/less anti-aromatic substituted-COT rings with benzene in the ben∥substituted-ben/ben∥substituted-COT complexes can be helpful to enhance strength of the π–π stacking interactions. Thus, regardless of ring size, the π–π stacking interaction is an aromatic–aromatic interaction and π electron cloud properties of interacting rings affect on the strength of this interaction. 相似文献
94.
The effect of interfacial microstructure on the lipid oxidation stability of oil-in-water emulsions 总被引:1,自引:0,他引:1
Novel rattle-type magnetic mesoporous carbon spheres are successfully prepared using composite spheres with Fe(3)O(4) as core and mesoporous SiO(2) as shell plus solid SiO(2) as a middle layer as templates. These rattle-type spheres possess the magnetization strength of as high as 37.5 emu/g, high and tunable specific surface areas (382-512.6 m(2)/g) due to mesoporous carbon shells. This magnetic rattle-type structure and the readily accessible mesoporous shell are very favoring for the fast adsorption and release of guest objects triggered by external stimulus, for example, the spheres showed very good adsorptive property to dye. 相似文献
95.
Guido Mann Jens Vogel Rüdiger Preuß Pouya Vaziri Mohammadali Zoheidi Markus Eberstein Jörg Krüger 《Applied Physics A: Materials Science & Processing》2008,92(4):853-857
High-power optical multimode fibers are essential components for materials processing and surgery and can limit the performance
of expensive systems due to breakdown at the end faces. The aim of this paper is the determination of laser-induced damage
thresholds (LIDT) of fibers (FiberTech) and preforms (Heraeus Suprasil F300). Preforms served as models. They were heated
up to maximum temperatures of 1100, 1300 and 1500°C and cooled down to room temperature at rates of 10 K min−1 (oven) and ∼105 K min−1 (quenched in air) to freeze in various structural states simulating different conditions similar to a drawing process during
the production of fibers. Single- and multi-pulse LIDT measurements were done in accordance with the relevant ISO standards.
Nd:YAG laser pulses with durations of 15 ns (1064 nm wavelength) and 8.5 ns (532 nm) at a repetition rate of 10 Hz were used.
For the preforms, LIDT values (1-on-1) ranged from 220 to 350 J/cm2 (1064 nm) and from 80 to 110 J/cm2 (532 nm), respectively. A multi-pulse impact changed the thresholds to lower values. The LIDT (1064 nm wavelength) of the
preforms can be regarded as a lower limit for those of the fibers. 相似文献
96.
Pouya Dastmalchi Nosrat Granpayeh Majid Rasouli Disfani 《Optical and Quantum Electronics》2010,42(4):231-239
In this paper we have investigated the performance of a nano-optical power splitter based on gap plasmon waveguides. The structure
consists of the rectangular gap plasmon waveguides in metal films. It is clear that the wave number and correspondingly light
confinement and the loss in the waveguides are the most effective parameters in power splitting, but as we know coupling length
is another important factor which should be considered. Some dependencies of the coupling length and the maximum transfer
power on the structure parameters are studied. It has been shown that approximately 43% transfer power for each arm of the
splitter is achievable. Simulation results have been obtained by the compact finite-difference time-domain method. The considered
structures, because of their small coupling length and dimensions are appropriate for implementation in photonic integrated
circuits. 相似文献
97.
Chenglong Luan Johanna Angona Arjun Bala Krishnan Manuel Corva Pouya Hosseini Markus Heidelmann Ulrich Hagemann Emmanuel Batsa Tetteh Wolfgang Schuhmann Kristina Tschulik Tong Li 《Angewandte Chemie (International ed. in English)》2023,62(28):e202305982
The role of β-CoOOH crystallographic orientations in catalytic activity for the oxygen evolution reaction (OER) remains elusive. We combine correlative electron backscatter diffraction/scanning electrochemical cell microscopy with X-ray photoelectron spectroscopy, transmission electron microscopy, and atom probe tomography to establish the structure–activity relationships of various faceted β-CoOOH formed on a Co microelectrode under OER conditions. We reveal that ≈6 nm β-CoOOH(01 0), grown on [ 0]-oriented Co, exhibits higher OER activity than ≈3 nm β-CoOOH(10 3) or ≈6 nm β-CoOOH(0006) formed on [02 - and [0001]-oriented Co, respectively. This arises from higher amounts of incorporated hydroxyl ions and more easily reducible CoIII−O sites present in β-CoOOH(01 0) than those in the latter two oxyhydroxide facets. Our correlative multimodal approach shows great promise in linking local activity with atomic-scale details of structure, thickness and composition of active species, which opens opportunities to design pre-catalysts with preferred defects that promote the formation of the most active OER species. 相似文献