Bragg Reflectors consist of periodic dielectric layers having an optical path length of quarter wavelength for each layer giving them important properties and makes them suitable for optoelectronics applications. The reflectivity can be increased by increasing the number of layers of the mirror to get the required value. For example for an 8 layers Bragg mirror (two layers for each dielectric pair), the contrast of the refractive index has to be equal to 0.275 for reaching reflectivity > 99%. Doubling the number of layers results in a reflectivity of 99.99%. The high reflectivity is purely caused by multiple-interference effects. It can be analyzed by using different matrix methods such as the transfer matrix method (TMM) which is the simplest method to study the characteristic of devices with different alternating layers.
running the requirement color important place in object of life activity both public and private, Fallon makes represents energy expressive and aesthetic in designing furniture street, especially (positions waiting buses passenger transport)which took looms large in attention receiver designer also, through civilized development and urban and change the city. Requirement, The positions of waiting progress jobs service and that would interact to produces Photos aesthetic Furniture for space street and understand receiver, affect the operation his life and the development of his environment and his psyche and culture of because they entity variable and sophisticated, impose on us to find foundations a design and conditions of chromatic esp
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The vegetative filter strips (VFS) are a useful tool used for reducing the movement of sediment and pesticide in therivers. The filter strip’s soil can help in reducing the runoff volume by infiltration. However, the characteristics of VFS (i.e., length) are not recently identified depending on the estimation of VFS modeling performance. The aim of this research is to study these characteristics and determine acorrelation between filter strip length and percent reduction (trapping efficiency) for sediment, water, and pesticide. Two proposed pesticides(one has organic carbon sorption coefficient, Koc, of 147 L/kg which is more moveable than XXXX, and another one
... Show MoreThe increase in population resulted in an increase in the consumption of water. The present work investigates the performance of a recycling solar- powered greywater treatment system for the purposes of irrigation, used to reduce the amount of waste grey water and reduce electricity consumption and reduce the costs of constructing large scale water treatment plants. The system consumes about 3814W per hour and provides water treatment about 1.4 m3 per day. The proposed system is designed to residential, office and governmental buildings application. Tests are conducted in an office building at the Ministry of Science and Technology site in Baghdad. Laboratorial water samples testing analyses are co
... Show MoreMany designs have been suggested for unipolar magnetic lenses based on changing the width of the inner bore and fixing the other geometrical parameters of the lens to improve the performance of unipolar magnetic lenses. The investigation of a study of each design included the calculation of its axial magnetic field the magnetization of the lens in addition to the magnetic flux density using the Finite Element Method (FEM) the Magnetic Electron Lenses Operation (MELOP) program version 1 at three different values of current density (6,4,2 A/mm2). As a result, the clearest values and behaviors were obtained at current density (2 A/mm2). it was found that the best magnetizing properties, the high
... Show MoreThis research involves design and simulation of GaussianFSK transmitter in UHF band using direct modulation of ΣΔ fractional-N synthesizer with the following specifications:
Frequency range (869.9– 900.4) MHz, data rate 150kbps, channel spacing (500 kHz), Switching time 1 µs, & phase noise @10 kHz = -85dBc.
New circuit techniques have been sought to allow increased integration of radio transmitters and receivers, along with new radio architectures that take advantage of such techniques. Characteristics such as low power operation, small size, and low cost have become the dominant design criteria by which these systems are judged.
A direct modulation by ΣΔ fractional-N synthesizer is proposed
... Show MoreWhat makes the commercial advertisement distinct is the design structure which is built according to artistic and creative concepts and terms based on the visual and formal interdependence relationships to express the motives of the advertising idea, which is based in its action mechanism on the effective variables, some of which are related to the marketing aspect, and others related to the advertisement aspect. The major aspect is the functional and aesthetic variables, which are represented by the vocabulary of the advertisement area for the open spaces such as the street ads. Its promotional dimension is the active forces in the circulation of commodities and products. Therefore, there would be significant problems the designe
... Show MoreThe icon and the symbol represent the constituents of the communication process, through their intellectual and philosophical concepts that have been addressed by the current research that it has touched upon their importance in conveying the design idea for the recipient and showing the specificity of each one of them in the communication process. The research problem has been limited by the following question: what are the communication roles that the symbol and the icon present for the user in designing the industrial product?
The research objective is to reveal the theoretical visualization that describes the icon and the symbol in the industrial product and its importance in the communication process through stating the of simil
Tests in the sports field constitute an essential tool for achieving optimal results and evaluating player performance, particularly in competitive sports such as basketball. The importance of shooting emerges as it is the only means of direct scoring and the critical statistic that distinguishes victory from defeat. The researchers observed that previous tests of basic shooting types whether administered individually or in combination do not adequately reflect the complexities of actual game situations. Therefore, the problem lies in the need to address this gap by designing a composite test that simulates various playing conditions related to basic shooting skills. The descriptive approach was adopted, and the research community was delib
... Show MoreIn this paper, tunable optical band-pass filters based on Polarization Maintaining Fiber –Mach Zehnder Interferometer presented. Tunability of the band-pass filter implemented by applying different mechanical forces N on the micro-cavities splicing regions (MCSRs). The micro-cavity formed by using three variable-lengths of single-mode polarization-maintaining fiber with (8, 16, 24) cm lengths, splice between two segments of (SMF-28) with (26, 13) cm lengths, using the fusion splicing technique. Ellipsoidal shape micro-cavities experimentally achieved parallel to the propagation axis having dimensions between (12-24) μm of width and (4-12) μm of length. A micro-cavity with width and length as high as 24 μm and 12 μ
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