نتایج جستجو برای: layers

تعداد نتایج: 103373  

2014
Uwe B Sleytr Bernhard Schuster Eva-Maria Egelseer Dietmar Pum

Monomolecular arrays of protein or glycoprotein subunits forming surface layers (S-layers) are one of the most commonly observed prokaryotic cell envelope components. S-layers are generally the most abundantly expressed proteins, have been observed in species of nearly every taxonomical group of walled bacteria, and represent an almost universal feature of archaeal envelopes. The isoporous latt...

2008
G. Carron

Given a complete non-compact surface Σ embedded in R, we consider the Dirichlet Laplacian in the layer Ω that is defined as a tubular neighbourhood of constant width about Σ. Using an intrinsic approach to the geometry of Ω, we generalise the spectral results of the original paper [1] by Duclos et al. to the situation when Σ does not possess poles. This enables us to consider topologically more...

2003
John Kim

The objective of this paper is to give an overview of recent progress on boundary layer control made by the author’s research group at University of California, Los Angeles. A primary theme is to highlight the importance of a certain linear mechanism and its contribution to skin-friction drag in turbulent boundary layers—and the implication that significant drag reduction can be achieved by alt...

Journal: :international clinical neurosciences journal 0
seifollah gholampour young researchers and elite club, tehran north branch, islamic azad university, tehran, iran keyvan hajirayat m.sc. student of biomechanical engineering, department of biomedical engineering, north tehran branch, islamic azad university, tehran, iran. armin erfanian b.sc. student, department of engineering, north tehran branch, islamic azad university, tehran, iran. ali reza zali md, professor of neurosurgery, shohada tajrish neurosurgical center of excellence, functional neurosurgery research center, shohada tajrish hospital, shahid beheshti university of medical sciences, tehran, iran. ehsan shakouri ph.d. assistant professor of mechanical engineering, department of manufacturing engineering, islamic azad university- north tehran branch, tehran, iran

background: motorcycle accidents and sport accidents lead yearly to many head injuries like head fractures and concussion. so finding the most proper helmet for reducing the injuries to head can be very helpful for head protection in such cases. methods: after 3d modeling of the helmet and head and meshing the model, a compressive impacting load of 1.31mpa was exerted on head and the model was ...

Journal: :فیزیک زمین و فضا 0
سمیرا محمدی کارشناس ارشد ژئوفیزیک (لرزه شناسی)، دانشگاه آزاد اسلامی واحد ساوه، ایران حمیدرضا سیاه کوهی دانشیار، گروه فیزیک زمین، موسسه ژئوفیزیک دانشگاه تهران، ایران

obtaining a seismic section with high temporal and spatial resolution was always one of the goals of seismic data processors and interpreters. accurate estimation of the thicknesses of thin beds is an important tool in this regard. the basic problem is that the wavelength of the signal must be similar in dimention to that of the bed thinness. if it is much longer than the bed thinness, the dete...

Journal: :journal of mechanical research and application 2010
habib esfandiar saeed adib nazari vahid monfared ali khatib

fiber metal laminates (fmls) are new composite materials consisting of thin metal layers and high strength composite layers. arall (aramid aluminum laminate) is a family of the fml that consists of thin aluminum sheets along with kevlar/epoxy composite layers. this material has many advantages such as light weight, excellent corrosion, fatigue and impact resistance. since, arall is a new materi...

Journal: :IACR Cryptology ePrint Archive 2014
S. M. Dehnavi A. Mahmoodi Rishakani M. R. Mirzaee Shamsabad Hamidreza Maimani Einollah Pasha

Diffusion layers are crucial components of symmetric ciphers. These components, along with suitable Sboxes, can make symmetric ciphers resistant against statistical attacks like linear and differential cryptanalysis. Conventional MDS diffusion layers, which are defined as matrices over finite fields, have been used in symmetric ciphers such as AES, Twofish and SNOW. In this paper, we study line...

2004
J. Höffner

Introduction Conclusions References Tables Figures Back Close Abstract Introduction Conclusions References Tables Figures Back Close Abstract In the past, many studies have been carried out to demonstrate the influence of me-teoroids on the atmospheric metal layer, observed roughly in the altitude range 80– 105 km. Even with the capability of present day resonance lidars to measure metal densit...

1986
S. A. Maslowe

The normal mode approach to investigating the stability of a parallel shear flow involves the superposition of a small wavelike perturbation on the basic flow. Its evolution in space and/or time is then determined. In the linear inviscid theory, if ū(y) is the basic velocity profile, then a singularity occurs at critical points yc, where ū = c, the perturbation phase speed. This is plausible in...

Journal: :Trends in cognitive sciences 2007
Geoffrey E Hinton

To achieve its impressive performance in tasks such as speech perception or object recognition, the brain extracts multiple levels of representation from the sensory input. Backpropagation was the first computationally efficient model of how neural networks could learn multiple layers of representation, but it required labeled training data and it did not work well in deep networks. The limitat...

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