نتایج جستجو برای: the attenuation parameters

تعداد نتایج: 16108098  

This paper proposes an analytical model for evaluating the performance of dense wavelength division multiplexing (DWDM) for all optical orthogonal frequency division multiplexing (AO-OFDM) optical wireless channel. The investigated performance for proposed system is evaluated for the parameters  bit error rate (BER) and Q factor .The constellation diagrams, and bit error rate (BER) of the recei...

Journal: :international journal of marine science and engineering 2013
l. mohajeri h. a. aziz m. h. isa m. a. zahed s. mohajeri

bioremediation, the process by which microorganisms degrade organic compounds to non-toxic or less toxic substances, has been widely used for cleanup of coastal ecosystems after oil spills. in this study, the hydrocarbon degradation rate and half lives in three bioremediation strategies (natural attenuation, biostimulation, and bioaugmentation) were compared in weathered crude oil (wco) contami...

2000
Felix Y. Wang

.......................................................................................................................ii ACKNOWLEDGEMENTS................................................................................................iii TABLE OF CONTENTS....................................................................................................iv LIST OF FIGURES...........................

Journal: :iranian journal of radiation research 0
i. akkurt suleyman demirel university science faculty physics department, isparta, turkey h. canakci gaziantep university engineering faculty civil engine department, bol. gaziantep, turkey

background: radiation shielding properties is an important for a material wish can be used the photon attenuation coefficients of clay produced using different rate of boron have been measured for the purpose of radioactive waste disposal. materials and methods: the measurement has been performed using gamma spectrometer contains nai (tl) detector at the photon energies of 662, 1173 and 1332 ke...

Journal: :anesthesiology and pain medicine 0
sussan soltani mohammadi department of anesthesiology, critical care and pain medicine, dr shariati hospital, tehran university of medical sciences, tehran, iran; department of anesthesiology, critical care and pain medicine, dr shariati hospital, tehran university of medical sciences, tehran, iran. fax: +98-21-88633039 alireza maziar department of anesthesiology, critical care and pain medicine, dr shariati hospital, tehran university of medical sciences, tehran, iran alireza saliminia department of anesthesiology, critical care and pain medicine, dr shariati hospital, tehran university of medical sciences, tehran, iran

conclusions there were no statistical differences between oral clonidine and intravenous lidocaine regarding attenuation of hemodynamic responses after tracheal intubation in controlled hypertensive patients, although the rate of complications including mouth dryness, bradycardia, and orthostatic hypotension was significantly higher in the clonidine group before induction of anesthesia. results...

1999
Philip B. Allen

Sound attenuation and internal friction coefficients are calculated for a realistic model of amorphous silicon. It is found that, contrary to previous views, thermal vibrations can induce sound attenuation at ultrasonic and hypersonic frequencies that is of the same order or even larger than in crystals. The reason is the internal-strain induced anomalously large Grüneisen parameters of the low...

1999
Jaroslav Fabian Philip B. Allen

Sound attenuation and internal friction coefficients are calculated for a realistic model of amorphous silicon. It is found that, contrary to previous views, thermal vibrations can induce sound attenuation at ultrasonic and hypersonic frequencies that is of the same order or even larger than in crystals. The reason is the internal strain induced anomalously large Grüneisen parameters of the low...

Journal: :The Journal of the Acoustical Society of America 2005
Andi G Petculescu Richard M Lueptow

In a previous paper [Y. Dain and R. M. Lueptow, J. Acoust. Soc. Am. 109, 1955 (2001)], a model of acoustic attenuation due to vibration-translation and vibration-vibration relaxation in multiple polyatomic gas mixtures was developed. In this paper, the model is improved by treating binary molecular collisions via fully pairwise vibrational transition probabilities. The sensitivity of the model ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه علوم کشاورزی و منابع طبیعی گرگان - دانشکده جنگلداری و مهندسی چوب و کاغذ 1391

درک الگوی توزیع مکانی ماکروفون خاک بدلیل اثرات آن روی فرآیندهای اکوسیستم بسیار مهم است. لیکن اطلاعات کمی در این خصوص وجود دارد. درمورد تنوع زیستی ارگانیسم ها وجانداران خاکزی که ازاجزای مهم وکلیدی درهرسیستم اکولوژیکی هستند و در بهبود حاصلخیزی خاک و تولیدات زمین وپایداری اکوسیستم ها(ازطریق فرآیندهای بیولوژیک)نقش عمده دارند تحقیقات کمی انجام شده است. این تحقیق جهت بررسی الگوی مکانی پارامترهای تنوع...

2005
R. R. Yadav D. K. Pandey

The ultrasonic attenuation is evaluated at 300 K along [100], [110], and [111] directions for the characterization of bcc metal Ta. The size of the metal is considered in nanorange. Ultrasonic velocity, Grüneisen parameter and acoustic coupling constant that depend on second and third order elastic constants are calculated for determination of ultrasonic attenuation coefficient. Second and thir...

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