نتایج جستجو برای: optical time

تعداد نتایج: 2116176  

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 ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سمنان - دانشکده شیمی 1392

چکیده در بخش اول این پروژه دو روش میکرواستخخرا به نامهای میکرواسخخرا امولسیونی با کمک اموا فراصتتتو 1 و میکرواستتتخخرا مای – مای با کمک هوا 2 ، به عنوان دو روش میکرواستتتخخرا بدون حلال پخشکننده 3 ، برای اسخخرا برخی هیتدروکربتنهای آروماتیتک حلقوی 4 از نمونتههای آبتی بهکار گرفخه و پارامخرهای موثری همچون نوع حلال اسختتتتخرا کننده، حجم حلال اسخخرا کننده، میزان نمک، زمان تابش اموا فراصتو ، تددا...

This paper deals with the design and simulation of all-optical 4×2 encoderusing the wave interference effect in photonic crystals. By producing 4 opticalwaveguides as input and two waveguides as output, the given structure was designed.The size of the designed structure is 133.9 μm2. The given all-optical encoder has acontrast ratio of 13.2 dB, the response time of 0.45 ...

Journal: :مهندسی برق و الکترونیک ایران 0
z. ghassemlooy wai pang ng h. le-minh

in future high-speed self-routing photonic networks based on all-optical time division multiplexing (otdm) it is highly desirable to carry out packet switching, clock recovery and demultplexing in the optical domain in order to avoid the bottleneck due to the optoelectronics conversion. in this paper we propose a self-routing otdm node structure composed of an all-optical router and demultiplex...

Saeed Olyaee, Shahram Mohammad Nejad,

In this paper, we present a high accuracy laser range finder and velocimeter using ultra-fast time-to-digital converter (TDC). The system operation is based on the measuring the round-trip time of a narrow laser pulse. A low-dark current high-speed PIN photodiode is used to detect the triggered laser beam and to produce start signal. The pulsed laser diode generates 45W optical power at 30ns du...

Background and Objectives: Recently, photonic crystals have been considered as the basic structures for the realization of various optical devices for high speed optical communication. Methods: In this research, two dimensional photonic crystals are used for designing all optical logic gates. A photonic crystal structure with a triangular lattice is proposed for making NAND, XNOR, and OR optica...

In this paper, an enhancement design of communication system using optical radio frequency (RF) waves in free space optical communication (FSO) system is presented. To our knowledge, it is the first time that the effect of Gamma-Gamma turbulent channel model on the performance of the proposed system is analyzed and simulated. To obtain an optical communication system with good performance and h...

Journal: :international journal of nano dimension 0
m. seyedsadjadi department of chemistry, science and research branch, islamic azad university, tehran, 1477892855 iran. f. asgari department of chemistry, science and research branch, islamic azad university, tehran, 1477892855 iran. n. farhadyar department of chemistry, varamin –pishva branch, islamic azad university, varamin, iran. n. molahasani department of chemistry, tehran shargh (qiamdasht) branch, islamic azad university, tehran, iran.

in this work, we report, optical properties of cd1-xsnxte quantum dots (x= 0.05, 0.10 and 0.15) synthesized in water using thioglycolic acid (tga) as a modifier agent. the optical characterization of the samples was performed through absorption (uv) and photoluminescence spectra (pl). a red shift absorption and fluorescent emission peaks was observed which can be related to the increase of nano...

حمید هراتی‌زاده, , مرتضی اسمعیلی, , پر اولاف هولتز, ,

Internal polarizations field which take place in quantum structures of group-III nitrides have an important consequence on their optical properties. Optical properties of wurtzite AlGaN/GaN quantum well (QW) structures grown by MBE and MOCVD on c-plane sapphire substrates have been investigated by means of photoluminescence (PL) and time resolved photoluminescence (TRPL) at low-temperature. PL ...

Journal: :polyolefins journal 2016
tao zheng qian li qian zhou huayi li qian xing

9,10-dihydro-9,10-ethano-anthracene-11,12-dicarboxylic acid disodium salt (dheas) was synthesized andused as a nucleating agent for poly(1-butene) (ipb). the isothermal crystallization kinetics of ipb havingdifferent nucleating agents were investigated by differential scanning calorimetry (dsc) and polarized opticalmicroscopy (pom). the results showed that the nucleating agents increased the cr...

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