نتایج جستجو برای: gpr

تعداد نتایج: 2556  

ژورنال: :فیزیک زمین و فضا 2013
ابوالقاسم کامکار روحانی اسماعیل اسحقی علیرضا عرب امیری

روش رادار نفوذی به زمین (gpr) به منزلة یک روش غیرتخریبی به منظور آشکارسازی اهداف زیرسطحی واقع در عمق کم، براساس ارسال امواج الکترومغناطیسی به درون زمین و ثبت بازتاب های دریافت شده از امواج ارسالی، مورد استفاده قرار می گیرد. دانه بندی ذرات و وجود رُس مواد زیرسطحی به دلیل تغییراتی که در میزان رسانندگی و گذردهی الکتریکی ایجاد می کنند و در نتیجه، ایجاد تغییر نسبی در عمق نفوذ امواج gpr قابل تشخیص و ب...

2007
J. M. Kruger L. Jordan

Introduction: The thickness of the lunar regolith and potential for frozen water are important considerations for future lunar outposts. However, the thickness of the regolith is largely unknown and the presence of water ice has yet to be directly detected at or beneath the surface. A rapid and economical geophysical method to determine both the thickness of the lunar regolith and possibly iden...

Journal: :int. journal of mining & geo-engineering 2014
reza ahmadi nader fathianpour gholam-hossain norouzi

to date, a number of numerical methods, including the popular finite-difference time domain (fdtd) technique, have been proposed to simulate ground-penetrating radar (gpr) responses. despite having a number of advantages, the finite-difference method also has pitfalls such as being very time consuming in simulating the most common case of media with high dielectric permittivity, causing the for...

2009
Mohammad Riahi Amirhossein Tavangar

The landmines presence causes serious safety hazards, which demand the clean up of contaminated land. Ground Penetrating Radar (GPR) is considered as a powerful nondestructive testing tool for high-resolution imaging of the shallow subsurface and its ability to detect both metallic and non-metallic landmines. The contrast in the dielectric constant between a landmine and the surrounding soil is...

Journal: :Journal of neurophysiology 1999
J T Birmingham Z B Szuts L F Abbott E Marder

The gastropyloric receptor (GPR) neurons of the stomatogastric nervous system of the crab Cancer borealis are muscle stretch receptors that can fire in either a spiking or a bursting mode of operation. Our goal is to understand what features of muscle stretch are encoded by these two modes of activity. To this end, we characterized the responses of the GPR neurons in both states to sustained an...

Journal: :Ecology 2007
Daniel B Stover L Frank P Day John R Butnor Bert G Drake

Growth and distribution of coarse roots in time and space represent a gap in our understanding of belowground ecology. Large roots may play a critical role in carbon sequestration belowground. Using ground-penetrating radar (GPR), we quantified coarse-root biomass from an open-top chamber experiment in a scrub-oak ecosystem at Kennedy Space Center, Florida, USA. GPR propagates electromagnetic w...

ژورنال: مهندسی معدن 2016

در مطالعه حاضر از روش رادار نفوذی به زمین (GPR) جهت تعیین مشخصات هندسی و فیزیکی اهداف استوانه­ای مدفون نظیر انواع ساختارهای تونلی استفاده شده است. برای این منظور از روش تطبیق الگو به­کمک روابط ریاضی موجود بین مشخصات هندسی هدف استوانه­ای شامل شعاع، عمق دفن و موقعیت افقی، با پارامترهای هذلولی پاسخ، استفاده شد. روش تطبیق الگو از طریق بکارگیری دو روش تعیین ...

2003
Lawrence Carin

GPR senses electrical inhomogeneities, with these manifested, for example, by the electrical contrast of a metal mine in the presence of a far-less-conducting soil background. Of much more difficulty, GPR senses the electrical inhomogeneity caused by a dielectric (plastic) landmine in the presence of soil. Often this contrast is very weak, implying that the landmine GPR signal is very small. Th...

2013
Juan Zhao Shu-Feng Zhang Yan Shi Li-Qun Ren

We investigated the eff ects of urantide, a receptor antagonist of urotensin II (U-II), on the expression of U-II and its receptor GPR in rat vascular smooth muscle cells. Vascular smooth muscle cells from rat thoracic aorta were cultured by explant method. Subjects in this experiment were divided into eight groups: normal control group (group C), U-II group (group M), positive control group ...

2000
S. Ebihara A. Yamamoto Y. Nakashima K. Takasawa

In this paper, results of GPR experiments carried out in Nalaih, Mongolia and Yakutsk, Russia will be shown. In the measurements, target is ground water and permafrost. Especially in these regions, there are special kind of permafrost structure, which are important in the study of permafrost. In Nalaih, there is “pingo”, which is composed of several layers including permafrost in the subsurface...

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