نتایج جستجو برای: vibration band gap
تعداد نتایج: 310115 فیلتر نتایج به سال:
فیلتری باساختارپریودیک سه گانه یک بعدی مطرح شده وروابط پراکندگی در ان بررسی میشود.با انالیز ریاضی می توان باندهای ممنوعه و مجاز طول موجها را با تغییرات زاویه فرودی پیش بینی کرد.با استفاده از روابط پراکندگی و با انتخاب مقادیر مناسب پارامترهای کنترلی میتوان طرح یک فیلتر اپتیکی را داد که می تواند در همه رنجهای طیف الکترومغناطیسی بکار گرفته شود.این مطالعه میتواند برای بهبود کارایی و دقت pbg(photoni...
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...
li2ni8o10 and limn2o4 nanoparticles as cathode materials of lithium ion battery, were successfully synthesized using lithium acetate, nickel and manganese acetate as li, ni and mn sources and stearic acid as a complexing reagent. the structure of the obtained products were characterized by ft-ir and xrd. the shape, size and distribution of the li2ni8o10 and limn2o4 nanoparticles were observed b...
In a three-dimensional topological insulator Bi2Se3, a stress control for band gap manipulation was predicted but no systematic investigation has been performed yet due to the requirement of large external stress. We report herein on the strain-dependent results for Bi2Se3 films of various thicknesses that are grown via a self-organized ordering process. Using small angle X-ray scattering and R...
The Photoexcited carrier lifetime (τ) and peak to valley transmission difference (ΔTp-v) in direct and indirect band gap crystals has been investigated by the use of single beam open and closed aperture z-scan technique using frequency doubled Nd:YAG laser. The peak to valley transmission difference (ΔTp-v) is found to be of the order of 10-2 in case of direct band gap crystals and of the order...
sol-gel derived sulfur modified and pure zno nanorod were prepared using zinc chloride and thiocarbamide as raw materials. prepared nanorods were characterized by means of x-ray diffraction (xrd), thermogravimetry- differential scanning calorimetry (tg–dsc), uv- vis absorption spectroscopy, brunauer emmett teller (bet) specific surface area and barrett joyner halenda (bjh) pore size distributio...
The electronic, optical, and lattice dynamical properties of tetracalcium trialuminate (Ca₄Al₆O13) with a special sodalite cage structure were calculated based on the density functional theory. Theoretical results show that Ca₄Al₆O13 is ductile and weakly anisotropic. The calculated Young's modulus and Poisson ratio are 34.18 GPa and 0.32, respectively. Ca₄Al₆O13 is an indirect-gap semiconducto...
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...
objectives: to evaluate different signal-processing algorithms for tactile identification of environmental sounds in a monitoring aid for the deafblind. two men and three women, sensorineurally deaf or profoundly hearing impaired with experience of vibratory experiments, age 22-36 years. methods: a closed set of 45 representative environmental sounds were processed using two transposing (trha, ...
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