نتایج جستجو برای: uniform structure

تعداد نتایج: 1661492  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه فردوسی مشهد - دانشکده ریاضی 1391

یک ابرگراف تعمیمی از گراف است که هر یال درآن ، که به آن ابریال می گویند ، می تواند شامل تعداد دلخواهی از رئوس باشد . مسئله جورسازی در ابرگراف ، پیدا کردن بزرگترین دسته ، از ابریال های مجزاست . این مسئله به خوبی در بهینه سازی ترکیبیاتی و نظریه گراف به همراه کاربردهای گوناگونش مورد مطالعه قرار گرفته است . در حالی که جورسازی روی گراف های معمولی در زمان چند جمله ای قابل حل است ، جورسازی در ابرگراف ...

2001

In this paper, we propose a novel method to test if a non-uniform filter bank can achieve perfect reconstruction via a tree structure. The set of decimators is first sorted in an ascending order. A non-uniform filter bank can achieve perfect reconstruction via a tree structure if and only if some or all of the channels corresponding to the maximum decimation ratio can be grouped into one channe...

2001
Ruey Bing Hwang

We present here an exact formulation for the three-dimensional (3-D) boundary-value problem of plane wave scattering by a two-dimensionally (2-D) periodic impedance surface in a uniform medium. The scattering characteristics of such a structure are rigorously analyzed in terms of the complete set of both TEand TM-polarized plane waves in the uniform medium. Extensive numerical results are given...

2001
Bingo Wing-Kuen Ling Peter Kwong-Shun Tam

In this paper, we propose a novel method to test if a non-uniform filter bank can achieve perfect reconstruction via a tree structure. The set of decimators is first sorted in an ascending order. A non-uniform filter bank can achieve perfect reconstruction via a tree structure if and only if some or all of the channels corresponding to the maximum decimation ratio can be grouped into one channe...

حمید رضا جاهد مطلق, , رامین جهادی نائینی, , محمد صدیقی, ,

In this paper, the effect of Equal Channel Angular Pressing (ECAP) process on the structure and mechanical properties of AM30 magnesium alloy was studied. The results showed a considerable effect of ECAP process on creating an ultrafine grain size structure. Scanning Electron Microscope indicated that the grain size dropped from 20.4 µm in the extruded form to 7.2 µm in the first pass and 3.9 µ...

Haji Abdolvahab, R., Molaeimanesh, Gh.R. ,

Proton exchange membrane (PEM) fuel cells being employed in fuel cell vehicles (FCVs) are promising power generators producing electric power from fuel stream via porous electrodes. Structure of carbon paper gas diffusion layers (GDLs) applying in the porous electrodes can have a great influence on the PEM fuel cell performance and distribution of temperature, especially at the cathode side whe...

Journal: :Dalton transactions 2015
Xingzhong Guo Rui Wang Huan Yu Yang Zhu Kazuki Nakanishi Kazuyoshi Kanamori Hui Yang

Hierarchically porous silica monoliths with well-defined interconnected macropores and uniform spherical mesopores were spontaneously prepared by combining polymerization-induced phase separation with an epoxide-mediated sol-gel route without any complicated aging and drying and high-temperature heat treatment. The precise control of pore structures can be realized by using propylene oxide (PO)...

2008
J H Van Der Walt

The aim of this paper is to set up appropriate uniform convergence spaces in which to reformulate and enrich the Order Completion Method [25] for nonlinear PDEs. In this regard, we consider an appropriate space ML (X) of normal lower semi-continuous functions. The space ML (X) appears in the ring theory of C (X) and its various extensions [15], as well as in the theory of nonlinear, PDEs [25] a...

Journal: :Physical review. E, Statistical, nonlinear, and soft matter physics 2009
Patrick S Salter Giovanni Carbone Sharon A Jewell Steve J Elston Peter Raynes

The symmetry of the cholesteric uniform lying helix (ULH) structure, where the helix axis is aligned in a single direction parallel to the device substrates, is not compatible with a uniform surface alignment and an unwinding of the helical structure is expected at the interface. Fluorescence confocal polarizing microscopy experiments are performed on the interface between a bulk ULH and a unif...

سلیمی, مهدی, سیفی شیروان‌ده, پیام, عسجدی, فاطمه, نیرهدی, روزبه,

In the present investigation, spherical nanoparticles of nickel ferrite with uniform structure were successfully produced by hydrothermal method in the presence of polyethylene glycol (PEG) as a polymeric surfactant at 180°C for 12 hour aging time and the effects of the synthesis time, temperature and surfactant were investigated. According to the X-ray analysis, conversion of nickel oxide ...

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