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111.
We report on room temperature ferromagnetism in C-doped ZnO thin films prepared by electron beam evaporation. Magnetization, Hall effect, X-ray photoemission spectroscopy (XPS) and X-ray diffraction studies have been conducted to investigate the source and nature of ferromagnetism in C-doped ZnO. The samples were observed to have n-type conduction with the carrier concentration increasing with C doping. XPS does not give any evidence for C substituted at the O site, and is more consistent with the formation of C-O bonds and with the presence of C primarily in the +4 state. It is suggested that the ferromagnetism originates in the development of Zn vacancies that are stabilized due to the incorporation of C in a high valence state (C4+). 相似文献
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114.
Giovanna Calò Gaetano Bellanca Ali Emre Kaplan Paolo Bassi Vincenzo Petruzzelli 《Optical and Quantum Electronics》2018,50(6):261
In this paper we present a double plasmonic Vivaldi antenna for on-chip optical wireless communication. The proposed antenna is a two-element broadside array fed by a silicon waveguide. The designs of the power splitter and of the hybrid Si-plasmonic coupler used for antenna excitation are described in detail. The array radiation characteristics are optimized through Finite Difference Time Domain simulations and the performance of a point-to-point link is evaluated. The proposed double Vivaldi array increases the gain of 3 dB with respect to a single antenna, improving the received power on a link of 6 dB when the double antenna is used for both transmitting and receiving sections. 相似文献
115.
Ashkan Ghanbari Alireza Kashaninia Ali Sadr Hamed Saghaei 《Optical and Quantum Electronics》2018,50(11):411
In this paper, femtosecond optical pulses compression and supercontinuum generation in a triangular silicon photonic crystal fiber at 2500 nm are investigated. A region of large minimum anomalous group velocity dispersion, negligible higher order dispersions and unique nonlinearity of silicon are used to demonstrate compression of 100 fs initial input optical pulses to 2.5 fs and ultra-broadband supercontinuum generation with very low input pulse energy over short distances of the fiber. 相似文献
116.
Ali Asghar Mohammadi Salman Taheri Arman Amini Reza Ahdenov 《Molecular diversity》2018,22(4):999-1006
Triamide derivatives have been synthesized in good yields in a novel, one-pot, five-component, and efficient process by the reaction of Z-oxazolone, water, primary amines, aldehydes, isocyanides, in the presence of catalytic amount of KAl(SO4)2·12H2O (alum) as a non-toxic, reusable, inexpensive, and easily available reagent via Ugi reaction in aqueous solution. 相似文献
117.
Ramandeep Behl Fiza Zafar Moin-ud-Din Junjua Ali Saleh Alshomrani 《Mathematical Methods in the Applied Sciences》2020,43(5):2421-2443
In most of the earlier research for multiple zeros, in order to obtain a new iteration function from the existing scheme, the usual practice is to make no change at the first substep. In this paper, we explore the idea that what are the advantages if the flexibility of choice is also given at the first substep. Therefore, we present a new two-point sixth-order scheme for multiple roots (m>1). The main advantages of our scheme over the existing schemes are flexibility at both substeps, simple body structure, smaller residual error, smaller error difference between two consecutive iterations, and smaller asymptotic error constant. The development of the scheme is based on midpoint formula and weight functions of two variables. We compare our methods with the existing methods of the same order with real-life applications as well as standard test problems. From the numerical results, we find that our methods can be considered as better alternates for the existing methods of the same order. Finally, dynamical study of the proposed schemes is presented that confirms the theoretical results. 相似文献
118.
Nuri Murat Yağmurlu Ali Sercan Karakaş 《Numerical Methods for Partial Differential Equations》2020,36(5):1170-1183
In this article, the equal width (EW) equation is going to be solved numerically. In order to show the accuracy of the presented method, six test problems namely single solitary wave, interaction of two solitary waves, interaction of three solitary waves, Maxwellian initial condition, undular bore, and soliton collision are going to be solved. For the first test problem, since it has exact solution, the error norms L2 and L∞ are going to be calculated and compared with some of the earlier studies existing in the literature. Moreover, the three invariants I1, I2, and I3 of the given problems during the simulations are calculated and tabulated. Besides those comparisons, the relative changes of the invariants are given. Finally, a comparison of those error norms and invariants has clearly shown that the present approach obtained compatible and better results than most of the earlier works by using the same parameters. 相似文献
119.
In this paper, we present a formulation of statistical mechanics of a thermodynamic system consisting of free particles and independent correlated pairs interacting via nonlocal potential in terms of the scattering properties. Some quantum statistical properties such as energy, heat capacity, second virial coefficient, virial pressure and quantum correction of kinetic energy are described analytically. The difference between the resolvents of the interacting and free Hamiltonians, represented as , that is associated with particle correlations is used for the evaluation of the properties. The statistical properties are related to correlated states, when making a pole expansion of the analytically continued momentum matrix element of . The present work illustrates these relations for a three-dimensional nonlocal separable potential of rank-two. 相似文献
120.
Jinyuan Liu Deming Shu Yujie Wang Suresh Narayanan Ali Mashayekhi Jun Qian Jin Wang 《Journal of synchrotron radiation》2007,14(1):138-143
The development of a sagittally focusing double‐multilayer monochromator is reported, which produces a spatially extended wide‐bandpass X‐ray beam from an intense synchrotron bending‐magnet source at the Advanced Photon Source, for ultrafast X‐ray radiography and tomography applications. This monochromator consists of two W/B4C multilayers with a 25 Å period coated on Si single‐crystal substrates. The second multilayer is mounted on a sagittally focusing bender, which can dynamically change the bending radius of the multilayer in order to condense and focus the beam to various points along the beamline. With this new apparatus, it becomes possible to adjust the X‐ray beam size to best match the area detector size and the object size to facilitate more efficient data collection using ultrafast X‐ray radiography and tomography. 相似文献