نتایج جستجو برای: Vibration Band gap

تعداد نتایج: 310115  

H.J Xiang, X.Y Yu Z.B Cheng Z.F Shi

A plate periodically bonded with piezoelectric patches on its surfaces is considered. The differential quadrature element method is used to solve the wave motion equation for the two-dimensional periodic structure. The method is very simple and easy to implement. Based on the method, band structures for in-plane wave propagating in the periodic piezoelectric plate are studied, from which the fr...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس - دانشکده علوم پایه 1390

در این تحقیق اتصال پپتیدی نانولوله به صفحات گرافن مورد بررسی قرار گرفته است. از میان جنبه های مختلف قابل بررسی برای این ساختارها، مطالعات ساختاری، مطالعات مربوط به انرژی تشکیل پیوند، مطالعاتnmr) )neuclear magnetic resonance و nuclear quadrupole resonance (nqr)و molecular electrostatic potential (mep)، مطالعات مربوط به شکاف انرژی (band gap)هریک از این هیبریدهای نانولوله - گرافن و همچنین بررسی ان...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه رازی - دانشکده علوم 1387

boron nitride semiconducting zigzag swcnt, $b_{cb}$$n_{cn}$$c_{1-cb-cn}$, as a potential candidate for making nanoelectronic devices was examined. in contrast to the previous dft calculations, wherein just one boron and nitrogen doping configuration have been considered, here for the average over all possible configurations, density of states (dos) was calculated in terms of boron and nitrogen ...

Journal: :journal of optoelectronical nano structures 0
khojasteh zarei 1department of electronic engineering, sepidan branch,islamic azad university, sepidan, iran. ghahraman solookinejad department of physics, marvdashtbranch,islamic azad university, marvdasht, iran. masoud jabbari department of electrical engineering, marvdasht branch, islamic azad university, marvdasht, iran.

in this paper, a photonic crystal waveguide with point defects and lattice constant perturbations of +5%, -5% are being investigated. firstly waveguide structures with constant and specific parameters are being studied and photonic band gap diagrams for te/tm modes are depicted; then pulse propagation in the frequencies available in the band gap are shown. after that, effects of parameters like...

Journal: :iranian journal of science and technology (sciences) 2013
m. aryadoust

the purpose of this paper is the generalization of structure factor for rods by polygon section in two dimensional phononic crystals. if we use the plane wave expansion method (pwe) for the propagation of acoustic waves in 2d phononic crystals, structure factor will be an important quantity. in order to confirm the obtained relations, we have calculated the band structure for xy and z vibration...

2007
Mahmoud I. Hussein Karim Hamza Gregory M. Hulbert Kazuhiro Saitou

∗ ABSTRACT The spatial distribution of material phases within a periodic composite can be engineered to produce band gaps in its frequency spectrum. Applications for such composite materials include vibration and sound isolation. Previous research focused on utilizing topology optimization techniques to design two-dimensional periodic materials with a maximized band gap around a particular freq...

Journal: :IOP Conference Series: Materials Science and Engineering 2017

پایان نامه :دانشگاه تربیت معلم - تهران - دانشکده علوم 1393

in this thesis, structural, electronical, and optical properties of inverse pervskite(ca3pbo) in cubic phase have been investigated.the calculation have been done based on density functional theory and according to generalized gradiant approximate (gga) as correlating potential. in order to calculate the configurations, implementing in the wien2k code have been used from 2013 version. first of ...

The need to design blast resistant civilian structures has arisen due to aggressor attacks on many civilian structures around the world. Achieving vibration and wave attenuation with locally resonant metamaterials has attracted a great deal of consideration due to their frequency dependent negative effective mass density. In this paper, metaconcrete, a new material with exceptional properties i...

Journal: :journal of nanostructures 2012
sh. khaleghi

by means of first principles calculations we show that both rutile and anatase phases of bulk tio2 doped by s, se or pb can display substantial decreasing in the band gap (up to 50%), while doping by zr does not sizably affect the band-gap value. moreover, the absorption edge is shifted (up to 1 ev) to the lower energy range in the case of tio2 doped by s or pb that opens a way to enhancing of ...

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