نتایج جستجو برای: resistivity

تعداد نتایج: 11971  

Journal: :J. Applied Mathematics 2013
Suchart Limkatanyu Woraphot Prachasaree Nattapong Damrongwiriyanupap Minho Kwon Wooyoung Jung

1 Department of Civil Engineering, Faculty of Engineering, Prince of Songkla University, Songkhla 90112, Thailand 2 Civil Engineering Program, School of Engineering, University of Phayao, Phayao 5600, Thailand 3Department of Civil Engineering, ERI, Gyeongsang National University, Jinju 660-701, Republic of Korea 4Department of Civil Engineering, Gangneung-Wonju National University, Gangneung 21...

2009
Rakesh P. Tiwari D. Stroud

We show that when bulk graphene breaks into n-type and p-type puddles, the in-plane resistivity becomes strongly field dependent in the presence of a perpendicular magnetic field even if homogeneous graphene has a field-independent resistivity. We calculate the longitudinal resistivity xx and Hall resistivity xy as a function of field for this system using the effective-medium approximation. Th...

Journal: :فیزیک زمین و فضا 0
صفا خزائی دانشگاه جامع امام حسین (ع) سید حسین موسوی آزاد

geophysical techniques remain the only ways to remotely and non-destructively sense the earth’s near subsurface and as such have the most promising prospect for rapid and accurate detection of underground tunnels. today, electrical resistivity and seismic refraction geophysical methods have been greatly developed to identify structures and underground cavities. in this study, the ability of the...

Journal: :فیزیک زمین و فضا 0
ابوالفضل اسدیان دانشجوی کارشناسی ارشد ژئوفیزیک، دانشکده مهندسی مهندسی معدن، نفت و ژئوفیزیک، دانشگاه شاهرود، ایران علی مرادزاده استاد، دانشکده معدن، پردیس دانشکده های فنی، دانشگاه تهران، علیرضا عرب امیری استادیار، دانشکده مهندسی مهندسی معدن، نفت و ژئوفیزیک، دانشگاه شاهرود، ایران علی نجاتی کلاته استادیار، دانشکده مهندسی مهندسی معدن، نفت و ژئوفیزیک، دانشگاه شاهرود، ایران داود رجبی دانش آموخته کارشناسی ارشد ژئوفیزیک، دانشکده مهندسی مهندسی معدن، نفت و ژئوفیزیک، دانشگاه شاهرود، ایران

helicopter-borne electromagnetic (hem) is a fast and high resolution airborne electromagnetic (aem) method that is frequently used for imaging of the subsurface resistivity structures. this is a versatile and cost effective method, frequently has used in mineral and groundwater exploration and various environmental problems. modern frequency-domain hem systems utilize small electromagnetic, mag...

2005
A J Wilday M W Ali

The objective of this study was to develop a methodology by which the risk from major accident hazards to the environment can be assessed or quantified. An index method, the Environmental Risk Index (ERI), has been developed based on an existing method, the Environmental Hazard Index (EHI), and the Department of the Environment (DoE) definitions of events that would constitute a major accident ...

2013
G. Fritsch J. Wilier E. Lüscher

Using the Ziman-formulation a model is derived which describes the pressure dependence of the electrical resistivity of d-electron amorphous alloys. It is shown how the volume dependence of the scattering-potential, electron-gas-properties and the Grüneisenparameter determine the P-dependence of a constant and a temperature dependent term in the resistivity. The absolute value of the resistivit...

2008
Yang Liu

This numerical study examines the importance of self-consistently accounting for transport and electrostatics in the calculaiton of semiconductor/metal Schottky contact resistivity. It is shown that ignoring such self-consistency results in significant under-estimation of the contact resistivity. An explicit numerical method has also been proposed to efficiently improve contact resistivity calc...

2014
Renjie Ji Yonghong Liu Ruiqiang Diao Chenchen Xu Xiaopeng Li Baoping Cai Yanzhen Zhang

Engineering ceramics have been widely used in modern industry for their excellent physical and mechanical properties, and they are difficult to machine owing to their high hardness and brittleness. Electrical discharge machining (EDM) is the appropriate process for machining engineering ceramics provided they are electrically conducting. However, the electrical resistivity of the popular engine...

2010
MAIRGARETH A. CHRISTMAN JOHN S. SPERRY

During vessel evolution in angiosperms, scalariform perforation plates with many slit-like openings transformed into simple plates with a single circular opening. The transition is hypothesized to have resulted from selection for decreased hydraulic resistance. Previously, additional resistivity of scalariform plates was estimated to be small – generally 10% or less above lumen resistivity – ba...

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