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11.
When a slightly divergent laser beam passes through a turbulent ground level atmosphere and strikes a linear grating, fluctuating self-images are formed at Talbot distances. By superimposing a similar grating on one of the self-images, even for the case of parallel gratings' lines, fluctuating moiré fringes are formed owing to the beam divergence. Recording the successive moiré patterns by a CCD camera and feeding them to a computer, after filtering the higher spatial frequencies, produces highly magnified fluctuations of the laser beam. Using moiré fringe fluctuations we have calculated the fluctuations of the angle of arrival and the atmospheric refractive index structure constant. The implementation of the technique is straightforward, a telescope is not required, fluctuations can be magnified more than ten times, and the precision of the technique is similar to that reported in our previous work. 相似文献
12.
S. H. Rasouli & H. Norouzi 《偏微分方程(英文版)》2015,28(1):1-8
We prove the existence of positive solutions for the system$$\begin{align*}\begin{cases}-\Delta_{p} u =\lambda a(x){f(v)}{u^{-\alpha}},\qquad x\in \Omega,\\-\Delta_{q} v = \lambda b(x){g(u)}{v^{-\beta}},\qquad x\in \Omega,\\u = v =0, \qquad x\in\partial \Omega,\end{cases}\end{align*}$$where $\Delta_{r}z={\rm div}(|\nabla z|^{r-2}\nabla z)$, for $r>1$ denotes the r-Laplacian operator and $\lambda$ is a positive parameter, $\Omega$ is a bounded domain in $\mathbb{R}^{n}$, $n\geq1$ with sufficiently smooth boundary and $\alpha, \beta \in (0,1).$ Here $ a(x)$ and $ b(x)$ are $C^{1}$ sign-changingfunctions that maybe negative near the boundary and $f,g $ are $C^{1}$ nondecreasing functions, such that $f, g :\ [0,\infty)\to [0,\infty);$ $f(s)>0,$ $g(s)>0$ for $s> 0$, $\lim_{s\to\infty}g(s)=\infty$ and$$\lim_{s\to\infty}\frac{f(Mg(s)^{\frac{1}{q-1}})}{s^{p-1+\alpha}}=0,\qquad \forall M>0.$$We discuss the existence of positive weak solutions when $f$, $g$, $a(x)$ and $b(x)$ satisfy certain additional conditions. We employ the method of sub-supersolution to obtain our results. 相似文献
13.
Sousan Rasouli Amir-Masoud Arabi Alireza Naeimi Seyed-Masoud Hashemi 《Journal of fluorescence》2018,28(1):167-172
Nanoparticles of Europium oxide doped with Zinc oxide were synthesized via microwave-assisted combustion method. Citric acid as a simultaneous fuel and chelating agent and glycine as a fuel and mixture of these fuels were sleeted. X-Ray diffraction patterns (XRD) indicated the formation of ZnO structure with a few amount of Eu2O3 phase. Fourier transformation infra red (FTIR) spectra reveal the increase of ZnO4 bonds with glycine content of fuels mixture. Scanning electron microscope (SEM) images showed the conversion of nanosphere to spongy-like structure with respect to change of fuel mixtures from citric to glycine. From transmission electron microscopy (TEM) nanoparticles of a mean size 30 nm are observed Green fluorescence emission of different samples was due to activation of self activated center of ZnO structure through transition of electron from Eu3+ to Vzn sites. 相似文献
14.
The behavior of electromagnetic fields near the edge of a plasmonic wedge is investigated. We study the scattering properties, field divergence, and field enhancement near an Au wedge bounded by SiO2 upon illumination by TM-polarized light using hypersingular integral equations, as a function of wavelength, wedge angle, and angle of incidence. The transverse scattered field components show a convergent behavior at wavelengths approaching the surface plasmon energy asymptote (on the corresponding flat Au-SiO2 interface), and become strongly divergent at longer wavelengths. The computed divergence is compared with Meixner's theory and is found to be in good agreement over a restricted range of parameters. 相似文献
15.
Mohammad Ali Rasouli Mohammad Mahdavi Parviz Rashidi Ranjbar Mina Saeedi Abbas Shafiee Alireza Foroumadi 《Tetrahedron letters》2012,53(52):7088-7092
This work describes a green and efficient one-pot synthesis of N-alkyl-2-(2-oxoazepan-1-yl)-2-arylacetamide derivatives via an Ugi four-center, three-component reaction of 6-aminohexanoic acid, aromatic aldehydes, and isocyanide derivatives in water under reflux conditions in the absence of a catalyst. 相似文献
16.
A. Nilchi M. Edalat M. Taghiof S. Rasouli Garmarodi 《Journal of Analytical Chemistry》2012,67(4):378-385
Due to the importance of application of lanthanides in various industries especially the nuclear ones, and the advantages
of capillary electrophoresis method in separation of metal cations, this research was carried out in order to investigate
the separation potential of lanthanides using capillary electrophoresis via simulation method at laboratory scale. Since the
properties of various types of lanthanides are very similar, the separation of lanthanides using the usual approaches was
not possible. Thus, the separation of lanthanides was devised upon partial, competing complexation in order to differentiate
their properties. Salicylic acid was firstly used as the primary UV-absorbing ligand, whereas formic, acetic, lactic, tartaric
and citric acids, which showed no absorption in UV-spectrum and had weaker complexes in comparison to salicylic acid, were
used as auxiliary ligands. Upon the results of spectrometry, the wave length of 210 nm was selected for detecting lanthanides.
The properties and stability of lanthanides were examined and furthermore acetic and citric acids were selected as auxiliary
ligands. The simulation was carried out with respect to the transport phenomena in the unsteady state. The ion species dissociation
was found to be directly dependent upon the concentration, and was also used in complexation. The results of simulation showed
that the diffusion control of H+ and homogenizing electrical field promoted separation quality. The separation conditions were optimized by using the simulation
results as well as the tests obtained. In order to optimize the experimental conditions, variable factors such as voltage,
injection time, pH, temperature and ionic strength were examined. Also, methanol was used as dissolving modifier as well as
noise reducer on the base line. Sodium nitrate was used as ionic strength controller and sucrose for increasing viscosity
which optimized separation quality. 相似文献
17.
Jalil Morshedian Hossein A. Khonakdar Sorour Rasouli 《Macromolecular theory and simulations》2005,14(7):428-434
Summary: A mechanical model was developed to describe qualitatively and quantitatively the stress‐strain‐time behavior of a prepared shape memory crosslinked polyethylene during hot stretching, stress relaxation under 200% strain at high temperature and strain recovery of the heat shrinkable polymer. The stress‐strain, the stress relaxation and the irrecoverable strain behavior of the model were established by driving the constitutive equation, which could qualitatively represent the behavior of the real material. By choosing significant values for the parameters of the proposed model, an excellent fit was obtained between the experimental behavior of the polymer and that predicted by the model. It was also revealed that the main source responsible for the imperfect recovery of the induced strain observed was the stress relaxation occurring during the stretch holding‐cooling time step.
18.
This paper addresses optimization of a high-speed digital feedback controller for a plasma position in Damavand tokamak. Damavand
tokamak discharges have plasma currents up to 40 kA with discharge duration greater than 15 ms and toroidal magnetic fields
up to 1.2 T. The plasma position is measured using saddle-loops and Rogowski coil and is controlled by electromagnetic forces
generated by passing currents through control coils placed around the plasma. A desired control objective is maintaining the
plasma in the center of vacuum vessel and to stabilize the plasma in the presence of disturbances in a time domain of the
order of few milliseconds. In order to achieve maximum performance it is essential to optimize the control system. In this
paper plasma position measurement and the details of implementing high-speed PID controllers based on a TMS320c25 digital
signal processor along with the system optimization are presented. 相似文献
19.
20.
S. M. M. Rasouli Mehrdad Farhoudi Nima Khosravi 《General Relativity and Gravitation》2011,43(10):2895-2910
We investigate the effects of a special kind of dynamical deformation between the momenta of the scalar field of the Brans–Dicke
theory and the scale factor of the FRW metric. This special choice of deformation includes linearly a deformation parameter.
We trace the deformation footprints in the cosmological equations of motion when the BD coupling parameter goes to infinity.
One class of the solutions gives a constant scale factor in the late time that confirms the previous result obtained via another
approach in the literature. This effect can be interpreted as a quantum gravity footprint in the coarse grained explanation.
The another class of the solutions removes the big bang singularity, and the accelerating expansion region has an infinite
temporal range which overcomes the horizon problem. After this epoch, there is a graceful exiting by which the universe enters
in the radiation dominated era. 相似文献