نتایج جستجو برای: 50 percent of gamma primaries and bottom

تعداد نتایج: 24121270  

2005
Gabriel Alvarez

Wave-equation migration with the velocity of the primaries maps non-diffracted waterbottom multiples to an hyperbola in subsurface-offset-domain-common-image-gathers. Furthermore, for positive surface offsets, the multiples are mapped to non-positive subsurface offsets if sediment velocity is faster than water. The larger the offset in the data space, the larger the subsurface offset and the sh...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه زنجان - دانشکده علوم انسانی 1389

abstract this study evaluated and compared medical terminology and english for the students of medicine (ii) as two representatives of the textbooks available on the iranian market for teaching english to the students of medicine. this research was performed on the basis of a teacher’s and a number of students’ attitudes and the students’ needs analysis for two reasons: first, to investigate...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه ارومیه 1377

‏‎applications such as high definition viedeo reproduction, portable computers, wireless, and multimedia demand, and ever-increasing need for ligh-frequency high-resolution and low-power analog-to-digital converters. flash, two-step flash, and pipeline convertors are fast but consume large amount of power and require large area. to overcome these problems, successive approximation converter blo...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه زنجان 1389

until now many studies have been done over recent decades throughout the world to show the right age to start english. in iran, research is still at an early stage in terms of evaluating teachers’ beliefs about teaching children english. the problem of at what age to start teaching english and how to teach english to elementary school children has not been solved neither in this country nor els...

پایان نامه :دانشگاه تربیت معلم - تهران - دانشکده ادبیات و علوم انسانی 1390

abstract the variables affecting the nature of reading comprehension can be classified into two general categories: reader’s variables, and text variables (alderson, 2000). despite the wave of research on vocabulary knowledge as reader’s variable, the role of this knowledge in c-test as a text-dependent test and its interaction with lexical cohesion of the test as a text feature has remained a...

پایان نامه :دانشگاه تربیت معلم - تهران - دانشکده ادبیات و علوم انسانی 1391

the present study aimed at exploring cognitions of iranian english teachers within the context of english for academic purposes (eap). to this end, the cognitions of two groups of eap teachers with respect to their pedagogical content knowledge (pck) and their sense of professional identity (pi) were probed. two language teachers and two content instructors who had at least five years of eap te...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی اصفهان - دانشکده شیمی 1389

in this thesis, a new optically active poly(amide-imide) (pai) was synthesized by the indirect polycondensation reaction of the l-phenylalanine based diacid chloride and 4,4?-diaminodiphenylether in the presence of triethylamine in n-methyl-2-pyrrolidone. the formation of pai was confirmed by ftir, 1h nmr and elemental analysis. in next step, the surface of titanium dioxide (tio2) nanoparticles...

1997
P. N. Bhat

In the absence of a standard source of gamma rays or hadrons of known energy one has to study the details of production of Čerenkov light at the observation level only through detailed simulation studies. Recently such studies have become all the more important in view of the various techniques resulting from such studies, to distinguish between gamma ray initiated events from those generated b...

Journal: :فیزیک زمین و فضا 0
ویدا مینائیان کارشناس ارشد مهندسی اکتشاف نفت، دانشکده مهندسی معدن، متالورژی و نفت دانشگاه صنعتی امیرکبیر، تهران، ایران عبدالرحیم جواهریان استاد بازنشسته، گروه فیزیک زمین، مؤسسه ژئوفیزیک، دانشگاه تهران و استاد دانشکده مهندسی نفت دانشگاه صنعتی امیرکبیر، تهران، ایران ابوالفضل مسلمی کارشناس ارشد ژئوفیزیک، شرکت عملیات اکتشاف نفت، تهران، ایران

reflection seismic data consist of primary reflections, coherent and incoherent noises. one of the objectives of seismic data processing is to enhance the quality of the real signals by attenuating different kinds of noises. multiples constitute one of the most troublesome forms of coherent noises in exploration seismology. multiple reflections often destructively interfere with the desired pri...

2006
Gabriel Alvarez

I propose a new method to attenuate specularly-reflected multiples in the image space. The method is based on the difference in mapping between primaries and multiples in Subsurface Offset Domain Common Image Gathers (SODCIGs). I migrate the data with a velocity slower than that of the primaries but faster than that of the multiples. The primaries are therefore undermigrated whereas the multipl...

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