http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
NUMERICAL SOLUTION OF A CLASS OF THE NONLINEAR VOLTERRA INTEGRO-DIFFERENTIAL EQUATIONS
Saeedi, L.,Tari, A.,Masuleh, S.H. Momeni The Korean Society for Computational and Applied M 2013 Journal of applied mathematics & informatics Vol.31 No.1
In this paper, we develop the operational Tau method for solving nonlinear Volterra integro-differential equations of the second kind. The existence and uniqueness of the problem is provided. Here, we show that the nonlinear system resulted from the operational Tau method has a semi triangular form, so it can be solved easily by the forward substitution method. Finally, the accuracy of the method is verified by presenting some numerical computations.
Silicon-photonic PTAT temperature sensor for micro-ring resonator thermal stabilization.
Saeedi, Saman,Emami, Azita Optical Society of America 2015 Optics express Vol.23 No.17
<P>We present a scheme for thermal stabilization of micro-ring resonator modulators through direct measurement of ring temperature using a monolithic PTAT temperature sensor. The measured temperature is used in a feedback loop to adjust the thermal tuner of the ring. The closed-loop feedback system is demonstrated to operate in presence of thermal perturbations at 20Gb/s.</P>
Mahdi Saeedi-Moghadam,Majid Pouladian,Mehrzad Lotfi,Reza Faghihi 한국자기학회 2019 Journal of Magnetics Vol.24 No.1
Purpose: This study aimed to present a protocol for constructing MRS phantoms that are supposed to be subjective of spectroscopy using 1.5T machines. Methods: As phantom containers, laboratory clear/amber glass bottles and an internally-designed Plexiglass and PVC cylinders were tested to evaluate the effect of phantom material and design on produced signals. HPLC and distilled-water were evaluated as solvent of metabolites. Finally, a protocol was suggested. Results: The results revealed that the physical walls of internally-designed phantom affect the WS and its baseline noise. The results also showed that even the amber-pigments inside the bottles can affect the MRS signal. Accordingly, the combination of HPLC-water inside clear-glass containers is suggested. Conclusion: The suggested protocol is as follows, apply clear-glass container as phantom body, do not build internal-structures using physical walls of glass or any other materials. Apply HPLC-water as solvent instead of distilled-water. Check the purity of chemical metabolites.
Khodabakhsh Saeedi,Alfin Leo,Rama B. Bhat,Ion Stiharu 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.5
"The free vibration of a circular plate with multiple perforations is analyzed by using the Rayleigh-Ritz method. Admissible functions are assumed to be separable functions of radial and tangential coordinates. Trigonometric functions are assumed in the circumferential direction. The radial shape functions are the boundary characteristic orthogonal polynomials generated following the Gram-Schmidt recurrence scheme. The assumed functions are used to estimate the kinetic and the potential energies of the plate depending on the number and the position of the perforations. The eigenvalues, representing the dimensionless natural frequencies, are compared with the results obtained using Bessel functions, where the exact solution is available. Moreover, the eigenvectors, which are the unknown coefficients of the Rayleigh-Ritz method, are used to present the mode shapes of the plate. To validate the analytical results of the plates with multiple perforations, experimental investigations are also performed. Two unique case studies that are not addressed in the existing literature are considered. The results of the Rayleigh-Ritz method are found to be in good agreement with those from the experiments. Although the method presented can be employed in the vibration analysis of plates with different boundary conditions and shapes of the perforations, circular perforations that are free on the edges are studied in this paper. The results are presented in terms of dimensionless frequencies and mode shapes."
The Effects of Non-Uniform Magnetic Field on the Concentration of Methane-Air Reaction Species
Ali. Saeedi,Javad. Khadem,Hojjat. Raznahan 한국자기학회 2020 Journal of Magnetics Vol.25 No.1
It is a well-known fact that the effects of magnetic fields on combustion can be used to control and optimize the flame deformation and the flame brightness. The kinetics and equilibrium properties of chemical reactions of combustion are influenced by the magnetic force exerted on paramagnetic species. In this study, the effects of non-uniform magnetic fields on one-stage methane combustion reaction are numerically investigated. It is known that NO, OH, and O₂ are paramagnetic species and the other species and methane have diamagnetic behavior. Considering these facts, the effects of non-uniform magnetic field on 10 main product species of methane combustion are studied, by minimization of the Gibbs free energy. The results indicate that variation of non-uniform magnetic fields from 0 to 0.08 Tesla leads to decrease in NO mole fraction by 99.6 % in temperature range 1500-2500 K. Furthermore, the combination of non-uniform magnetic field and raising the pressure have the beneficial result in decreasing NO and CO mole fractions as well as rise in temperature.
Alireza Saeedi Azizkandi,Mohammad Hasan Baziar,Ali Fallah Yeznabad 대한토목학회 2018 KSCE Journal of Civil Engineering Vol.22 No.5
Connected and disconnected piled raft foundations have been evaluated under lateral cyclic loading in this study. Connected PiledRaft (CPR) and nonconnected piled (NPR) foundations were considered and evaluated in 1-g shaking table tests. FEM numericalmodelling also was employed to evaluate the results. The responses were evaluated and compared using lateral movement of caps,moments and lateral loads along the piles and ground settlements. The results indicate that both nonconnected and connected piledraft foundations effectively reduce the ground settlements, however, connected piled rafts have much higher lateral stiffness and pilescontribute to lateral load bearing mechanism more effectively; in connected piled raft, piles bear higher moments and lateral loadsand reduce lateral movements more effectively. The cap weight and superstructure (central mass height) effect has been consideredthrough supplementary numerical assessments for CPR case. Superstructure addition tends to increase the pile moment and raftinclination where the frequency effect is also critically important. Also heavier cap experiences higher rotations and associated withhigher induced loads to piles.
Al-Saeedi F.H.F.,Sayyed M.I.,Kapustin F.L.,Al-Ghamdi Hanan,Kolobkova E.V.,Tashlykov O.L.,Almuqrin Aljawhara H.,Mahmoud K.A. 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.8
In the present work, untreated Iraqi sand with grain sizes varied between 100 and 200 mm was used to produce a colored glass sample that has shielding features against the low gamma-ray energy. Therefore, a weight of 70e60 wt % sand was mixed with 9e14 wt% B2O3, 8e10 wt% Na2O, 4e6 wt% of CaO, 3e6 wt% Al2O3, in addition to 0.3% of Co2O3. After melting and annealing the glass sample, the X-ray diffraction spectrometry was applied to affirm the amorphous phase of the fabricated glass samples. Moreover, the X-ray dispersive energy spectrometry was used to measure the chemical composition, and the MH-300A densimeter was applied to measure the fabricated sample's density. The Makishima-Makinzie model was applied to predict the mechanical properties of the fabricated glass. Besides, the Monte Carlo simulation was used to estimate the fabricated glass sample's radiation shielding capacity in the low-energy region between 22.1 and 160.6 keV. Therefore, the simulated linear attenuation coefficient changed between 10.725 and 0.484 cm1 , raising the gamma-ray energy between 22.1 and 160.6 keV. Also, other shielding parameters such as a half-value layer, pure lead equivalent thickness, and buildup factors were calculated
The Impact of MRS Phantom Container on the Quality of Spectrum Provided by 3T MRI
Mahdi Saeedi-Moghadam,Mehrzad Lotfi,Banafsheh Zeinali-Rafsanjani,Reza Jalli 한국자기학회 2020 Journal of Magnetics Vol.25 No.3
This study intended to evaluate the effect of the material of phantom-container on the MRS signal in 3T MRI. Three phantom-container consisting of clear laboratory-glass, PET-bottle, and falcon-tube was used. The metabolites contained 6 mM Cr and 3 mM Cho. FWHM and SNR of Cho and both peaks of Cr were calculated. FWHM of all the peaks of glass-phantom was 50.08 and 19.48 % fewer than those provided by PET and falcon-tube; also, the SNR of the all the peaks of the PET and falcon-tube were by average 77.99 and 91.18 % fewer than the peaks provided by glass-phantom. The laboratory-glass is a good material for building MRS phantoms since it does not affect the baseline-noise, FWHM, and SNR of the spectra. It was also revealed that the size of the phantom and the distance between the spectroscopy volume and phantom walls were important and can affect the baseline-noise.