نتایج جستجو برای: poissons equation

تعداد نتایج: 230305  

2012

This paper presents a numerical study of the deposition of submicron charged spherical particles caused by convection, Brownian and turbulent diffusion in a pipe with a smooth wall and with a cartilaginous ring wall structure. The model is supposed to describe deposition of charged particles in generation 0 (trachea) of the human lung. The upper airways of the human lung are characterized by a ...

Journal: :Revue suisse de zoologie. 1987

Journal: :La Houille Blanche 1996

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تبریز - دانشکده ریاضی 1393

در ابتدا به طور مختصر ارتباط بین مسائل تغییراتی و معادلات دیفرانسیل را بیان می کنیم. همان طور که می دانیم هر معادله دیفرانسیل را می توان به صورت ‎egin{equation} label{yek}‎ ‎a(u)= 0‎ ‎end{equation}‎ نوشت، که در آن ‎$ a(u) $‎ یک عملگر دیفرانسیل معمولی یا جزئی خطی یا غیرخطی و ‎$ u $‎ مجهول می باشد. برای حل این معادلات و به خصوص معادلات دیفرانسیل جزیی غیرخطی راه حل مشخصی وجود ندارد.حساب تغییر...

2006
Thomas R. Hrabik Olaf P. Jensen Steven J.D. Martell Carl J. Walters James F. Kitchell

The distribution of fishes is influenced by a host of physico-chemical and biological variables, including temperature and oxygen, prey abundance, feeding or assimilation rates, and predation risk. We used hydroacoustics and midwater trawls to measure the vertical distribution of pelagic fishes during a series of research cruises on Lake Superior’s western arm in 2001 and 2004. Our objective wa...

2004
Yves-Marie BOZEC Jocelyne FERRARIS Didier GASCUEL Michel KULBICKI

Ecosystem indicators were investigated through the study of the trophic structure of reef fish assemblages, in separate coral reef ecosystems of the south-west lagoon of New Caledonia. In a first step, a fractional trophic level was assigned for each fish species. Abundances profiles along trophic levels were subsequently plotted in order to search for trophic changes under various level of fis...

2008
Mark S. Poos Nicholas E. Mandrak Robert L. McLaughlin

Science-based approaches for selecting among single-species, community-, and ecosystem-based recovery plans are needed to conserve imperilled species. Selection of recovery plans has often been based on past success rates with other taxa and systems or on economic cost, but less on the ecology of the system in question. We developed a framework for selecting a recovery plan based on the distrib...

2005
Donald L. DeAngelis Joel C. Trexler William F. Loftus

We used a one-dimensional, spatially explicit model to simulate the community of small fishes in the freshwater wetlands of southern Florida, USA. The seasonality of rainfall in these wetlands causes annual fluctuations in the amount of flooded area. We modeled fish populations that differed from each other only in efficiency of resource utilization and dispersal ability. The simulations showed...

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