نتایج جستجو برای: rf because of low signal

تعداد نتایج: 21269979  

2008
Dick J Drost Peter Williamson Rob Nicolson

Magnetic Resonance Imaging (MRI) employs a strong static magnetic field, time changing magnetic fields and RF fields to produce diagnostic images whose grey levels represent the MR signal from hydrogen nuclei in tissue water molecules and hydrocarbon chains (fat). MRI can also been done with MR signals from hydrogen nuclei attached to other molecules, for example, neurotransmitters (Glutamate a...

پایان نامه :0 1374

this experimental study has been conducted to test the effect of oral presentation on the development of l2 learners grammar. but this oral presentation is not merely a deductive instruction of grammatical points, in this presentation two hypotheses of krashen (input and low filter hypotheses), stevicks viewpoints on grammar explanation and correction and widdowsons opinion on limited use of l1...

2013
Phirun Kim Girdhari Chaudhary Yongchae Jeong

Abstract—In this paper, a novel dual-band RF-harvesting RF-DC converter with a frequency limited impedance matching network (M/N) is proposed. The proposed RF-DC converter consists of a dual-band impedance matching network, a rectifier circuit with villard structure, a wideband harmonic suppression low-pass filter (LPF), and a termination load. The proposed dual-band M/N can match two receiving...

Journal: :IEEE Photonics Technology Letters 2019

Journal: :NMR in biomedicine 2010
Elodie Breton Kellyanne McGorty Graham C Wiggins Leon Axel Daniel Kim

High-field (≥ 3T) MRI provides a means to increase the signal-to-noise ratio, due to its higher tissue magnetization compared with 1.5T. However, both the static magnetic field (B(0)) and the transmit radio-frequency (RF) field (B 1+) inhomogeneities are comparatively higher at higher field strengths than those at 1.5T. These challenging factors at high-field strengths make it more difficult to...

پایان نامه :دانشگاه آزاد اسلامی - دانشگاه آزاد اسلامی واحد علوم دارویی - پژوهشکده علوم 1392

purpose a metabolic abnormality such as obesity is a major obstacle in the maintenance of the human health system and causes various chronic diseases including type 2 diabetes, hypertension, cardiovascular diseases, as well as various cancers. this study was designed to summarize the recent scientific knowledge regarding the anti-obesity role of curcumin (diferuloylmethane), which is isolated f...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه ارومیه 1381

برای پردازش سیگنال آنالوگ در شبکه های عصبی ، معمولا نیاز به یک واحد حافظه آنالوگ احساس میشود که بدون احتیاج به ‏‎a/d‎‏ و‏‎d/a‎‏ بتواند بطور قابل انعطاف و مطمئن اطلاعات آنالوگ را در خود ذخیره کند. این واحد حافظه باید دارای دقت کافی ، سرعت بالا ، توان تلفاتی کم و سایز کوچک باشد و همچنین اطلاعات را برای زمان کافی در خود نگهدارد. برای پیاده سازی سیستمی که همه این قابلیتها را در خود داشته باشد، کوشش...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه علامه طباطبایی - دانشکده اقتصاد 1391

reinsurance is widely recognized as an important instrument in the capital management of an insurance company as well as its risk management tool. this thesis is intended to determine premium rates for different types of reinsurance policies. also, given the fact that the reinsurance coverage of every company depends upon its reserves, so different types of reserves and the method of their calc...

Journal: :Magnetic Resonance in Medicine 2009

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