نتایج جستجو برای: energy x
تعداد نتایج: 1227904 فیلتر نتایج به سال:
در این تحقیق اثر الکترونگاتیوی برای استخلاف های f, cl, no2 , cf3 برروی آروماتیسیته مولکول بنزن مورد مطالعه قرار گرفته است. nics, ase, homa, homo-lumo energy gapsشاخص هایی هستند که برای نمایش تاثیر استخلاف ها به کار برده می¬شوند.علاوه بر این الکترون های انتقالی توسط پیوند سیگما وپای نیز برای همه مولکول های استخلاف شده مورد نظر محاسبه شده¬اند.نتایج بدست آمده برای این روش ها با یکدیگر متفاوت است.ب...
The aim of this research is to determine the possible solar energy storage in the norbornadiene (1) / quadricyclane (2) system, through involving steric effects on various position of carbon C1, C2 or C7 for 1 and 2; calculating the corresponding energies at B3LYP/6-311G** level of theory. The extent of the solar energy storage is the least for 11-i-Pr (-21.018), 12-t-Bu (-22.525) and 17-i-Pr (...
Dual-energy X-ray computed tomography (DECT) is a technique which is designed to allow the determination of energy-independent material properties. In this study, results of a computer simulation show that energy-dependent systematic errors exist in the values of attenuation coefficients synthesized using the basis material decomposition technique with acrylic and aluminum as the basis material...
Objective: In this study, we aimed to validate the accuracy of computed tomography-based attenuation correction (CTAC) using the bilinear scaling method.Methods: The measured attenuation coefficient (μm) was compared to a theoretical attenuation coefficient (μt ) using four different CT scanners and an RMI 467 phantom. The effective energy of the CT beam X-rays was calculated, using the aluminu...
progressive loss of bone mineral density around the femora! component of total hip replacement continues to pose a threat to long term prosthetic survival. a linear study was undertaken to measure bone mineral density on a monthly basis following total hip arthroplasty in 11 male patients. the opposite femur was used as the control measurement. bone mineral density was unchanged at two months f...
Mn doped ZnO nanocrystals were prepared by co-precipitation route sintered at 450 °C temperature. XRD results indicate that the samples having hexagonal (wurtzite) structure. From X-ray data it is found that the lattice parameters increase with increasing Mn concentration. The X-ray density decreases with increasing Mn concentration of Zn 1-x Mnx O nanocrystals. It indicates that the Mn...
Neurons in area MT of primate visual cortex encode the velocity of moving objects. We present a model of how MT cells aggregate responses from V1 to form such a velocity representation. Two diierent sets of units, with local receptive elds, receive inputs from motion energy lters. One set of units forms estimates of local motion, while the second set computes the utility of these estimates. Out...
In this study, BaZr1-xCoxO3 nanoparticles, x = 0.00, 0.04, 0.06, 0.08, 0.10 and 0.20, are synthesized through co-precipitation method. Therefore, structural, optical and magnetic properties have been investigated. The cubic perovskite structure is confirmed by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopic measurements. The average crystallite size and micro strain ...
Background and purpose: Dual-energy mammography technique is used for improving the accuracy of breast cancer diagnosis especially in dense breast cases and also detection of micro-calcifications which are early signs of breast cancer. The purpose of this study was to investigate the automatic separation feasibility of micro-calcification images in breast tissue images and evaluating its accura...
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