نتایج جستجو برای: frequency response

تعداد نتایج: 1408754  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی خواجه نصیرالدین طوسی - دانشکده مهندسی برق و کامپیوتر 1391

power transformers are important equipments in power systems. thus there is a large number of researches devoted of power transformers. however, there is still a demand for future investigations, especially in the field of diagnosis of transformer failures. in order to fulfill the demand, the first part reports a study case in which four main types of failures on the active part are investigate...

Journal: :iranian journal of radiation research 0
a. mirzajani medical physics group, tehran university of medical sciences, tehran, iran n. riyahi-alam medical physics group, tehran university of medical sciences, tehran, iran m.a. oghabian medical physics group, tehran university of medical sciences, tehran, iran k. firuznia radiology group, tehran university of medical sciences, tehran, iran h. saberi neurosurgery group, tehran university of medical sciences, tehran

abstract  background: the brain response to temporal frequencies (tf) has been already reported, but with no study reported for different tf with respect to various spatial frequencies (sf).  materials and methods: fmri was performed by 1.5t ge-system in 14 volunteers during checkerboard, with tfs of 4, 6, 8 and 10hz in low and high sfs of 0.5 and 8cpd.  results: average percentage bold signal ...

Journal: :iranian journal of electrical and electronic engineering 0
منیری moniri فرشاد farshad

power transformers are key components in electrical power supplies and their failure could cause severe consequences on continuity of service and also generates substantial costs. identifying problems at an early stage, before catastrophic failure occurs, is a great benefit for reliable operation of power transformers. frequency response analysis (fra) is a new, well-known and powerful diagnost...

Journal: :journal of structural engineering and geo-techniques 2012
a esfandiari

in this paper, a structural damage identification method (sdim) is developed for plate-like structures. this method is derived using dynamic equation of undamaged/damaged plate, in which local change in flexural rigidity is characterized utilizing a damage distribution function. the sdim requires to modal data in the intact state and frequency response of damage state where most of vibration ba...

Journal: :international journal of nanoscience and nanotechnology 2015
e. maani miandoab f. tajaddodianfar h. nejat pishkenari h. m. ouakad

many of nonlinear systems in the field of engineering such as nano-resonator and atomic force microscope can be modeled based on duffing equation. analytical frequency response of this system helps us analyze different interesting nonlinear behaviors appearing in its response due to its rich dynamics. in this paper, the general form of duffing equation with cubic nonlinearity as well as paramet...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 2012
amir heidari mansour shirvani

in this contribution, linearized dynamic model of cumulative mass fraction (cmf) of potassium nitrate-water seeded continues mixed suspension mixed product removal (cmsmpr) crystallizer is approximated by a simplified model in frequency domain. frequency domain model simplification is performed heuristically using the frequency response of the derived linearized models data. however, the cmf fr...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تحصیلات تکمیلی صنعتی کرمان - پژوهشکده برق و کامپیوتر 1390

a phase-locked loop (pll) based frequency synthesizer is an important circuit that is used in many applications, especially in communication systems such as ethernet receivers, disk drive read/write channels, digital mobile receivers, high-speed memory interfaces, system clock recovery and wireless communication system. other than requiring good signal purity such as low phase noise and low spu...

Amir Heidari Mansour Shirvani,

In this contribution, linearized dynamic model of Cumulative Mass Fraction (CMF) of Potassium Nitrate-Water Seeded Continues Mixed Suspension Mixed Product Removal (CMSMPR) crystallizer is approximated by a simplified model in frequency domain. Frequency domain model simplification is performed heuristically using the frequency response of the derived linearized models data. However, the CM...

Journal: :The Journal of the Acoustical Society of America 1947

Journal: :journal of nanostructures 2013
n. manavizadeh f. raissi e. asl-soleimani

the performance of nanoscale field effect diodes as a function of the spacer length between two gates is investigated. our numerical results show that the ion/ioff ratio which is a significant parameter in digital application can be varied from 101 to 104 for s-fed as the spacer length between two gates increases whereas this ratio is approximately constant for m-fed. the high-frequency perform...

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