نتایج جستجو برای: at both low and high frequencies

تعداد نتایج: 17484187  

Dong-Soo, Kim, Wook Choo, Yun, حسن بازیار, محمد, رابطی مقدم, مسعود,

In this paper,  a numerical model  was first verified against dynamic centrifuge tests results performed on an underground subway tunnel and then, the effect of underground structure on peak ground acceleration (PGA) at the ground surface investigated considering linear and nonlinear behavior for the soil. The results show that in the range of natural frequency of the system, nonli...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس - پژوهشکده مهندسی فرایند 1395

abstract: mineral scaling in oil and gas production equipment is one of the most important problem that occurs while water injection and it has been recognized to be a major operational problem. the incompatibility between injected and formation waters may result in inorganic scale precipitation in the equipment and reservoir and then reduction of oil production rate and water injection rate. ...

Journal: :The Journal of the Acoustical Society of America 1972

  Introduction:   The daf is a large Persian frame drum used as a musical instrument in both popular and classical music which can induce a percussive sound at low frequencies (146–290 Hz) with peaks of up to 130 dBspl. The percussive sounds have a power distribution in the region of saccular sensitivity. In view of the saccular stimulation by sound in humans, we decided to use cervical vestibu...

2003
Aleksandar Tasic Wouter A. Serdijn John R. Long

Higher transistor transition frequencies, lower supply voltages and smaller physical dimensions are, nowadays, general trends in the semiconductor industry. Operating at lower supply voltages often results in a low-power design, smaller dimensions allow the use of a large number of transistors and a high transition frequency (fT) opens the way to design of amplifiers with ever-higher gains and ...

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 ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تحصیلات تکمیلی علوم پایه زنجان - دانشکده فیزیک 1392

in the first part of this thesis we explored wetting and its dynamics for small droplets. first, we showed how a simple feature of water droplets on a surface, i.e. laplace pressure, can be exploited to build a micropump. we investigated capillary pumping in microchannels both experimentally and numerically. putting two droplets of different sizes at the in/outlet of a microchannel, will ge...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سمنان 1392

in the area of vocabulary teaching and learning although much research has been done, only some of it has led to effective techniques of vocabulary teaching and many language learners still have problem learning vocabulary. the urge behind this study was to investigate three methods of teaching words. the first one was teaching words in context based on a traditional method of teaching that is,...

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