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Gain enhancement in two-stream free electron laser with a planar wiggler and an axial guide magnetic field

Chinese Physics B 2012年第9期21卷 247-250页

作者： S.Saviz z.rezaei Farzin M.Aghamir Plasma Physics Research Center Science and Research BranchIslamic Azad University Department of Physics University of Tehran

The theory for a two-stream free electron laser （FEL） consisting of a relativistic electron beam transported alongthe axis of a planar wiggler in the presence of an axial guiding magnetic field is proposed and investigated. The electron trajectories and the small signal gain are derived. The characteristic of the linear gain and the normalized maximum gain are studied numerically. The result shows that the normalized maximum gain is considerably enhanced in comparison with that of the single stream. The effect of the difference between the energies of the two beams in this configuration of FEL is also considered, and we find that the gain is affected by the energy differences between groups 1 and 2.

关键词： wo-stream free-electron laser

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A novel frequency-selective metamaterial to improve helix antenna

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Journal of zhejiang University-Science C(Computers and Electronics) 2012年第5期13卷 365-375页

作者： Iraj ARGHAND LAFMAJANI Pejman rezaei Department of Electrical and Computer Engineering Semnan University

A novel frequency-selective metamaterial with negative permittivity and permeability for improving directivity and gain of a helix antenna is presented in this *** proposed metamaterial is composed of two z-shape resonators printed on opposite sides of a dielectric *** forms of multilayered cells are found to be suitable for antennas and waveguides *** addition,a new method of designing a metamaterial-based helix antenna is presented with high directivity and gain.A comparison on radiation properties is given between the conventional and the new metamaterial-based helix *** comparisons on radiation properties are performed:(1) the effect of proposed z-structure on monopole,dipole,and helix antennas;(2) the effect of OE3,split-ring resonator (SRR),and proposed z-structure unit cells on the performance of helix *** results show improvement of parameters such as directivity,gain,and radiation power of the new metamaterial-based helix ***,the combination of z-structure with the helix antenna shows the best performance.

关键词： Antenna efficiency Negative permittivity Negative permeability Helix antenna Metamaterial

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Effects of the mass and volume shrinkage of ground chip and pellet particles on drying rates

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Particuology 2018年第3期16卷 1-9页

作者： Hamid rezaei Shahab Sokhansaj C. Jim Lim Anthony Lau Xiaotao Bi Chemical and Biological Engineering Department University of British Columbia Vancouver BC V6T 1Z3 Canada Environmental Science Division Oak Ridge National Laboratory Oak Ridge TN 37381 USA

The effects of varying the mass and volume of ground chip and pellet particles on the particle drying rate were analyzed. Samples of whole pellets and chips were hammer milled using a 3.2 mm screen and the ground chip and pellet particles were found to have similar size distributions, although the pellet particles were denser and more spherical than the chip particles. Prior to drying, water was added to the particles to obtain 0.10, 0.30, 0.50, 0.70, and 0.90 moisture contents （on a dry mass basis）. The moistened particles were subsequently dried in a constant temperature thin layer dryer set at 50,100, 150, or 200 ~C under dry pure nitrogen, dry compressed air, or atmospheric air. The chip and pellet particles exhibited similar degrees of shrinkage, but the pellet particles underwent a greater reduction in their bulk volume during drying. It appears that the more spherical pellet particles are prone to shrinkage in more than one direction, whereas the needle-like chip particle shrink only in one direction. A variable radius first order drying model was found to fit the experimental data better than a fixed radius model.

关键词： Moisture loss Particle density Ground chip Ground pellet Particle shrinkage Bulk shrinkage

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Benzene degradation in waste gas by photolysis and photolysis-ozonation： experiments and modeling

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Frontiers of Environmental Science & Engineering 2016年第6期10卷 103-112页

作者： Fariba Mahmoudkhani Maryam rezaei Vahid Asili Mahsasadat Atyabi Elena Vaisman Cooper H. Langford Alex De Visscher Department of Chemical and Petroleum Engineering Centre for Environmental Engineering Research and Education (CEERE) Schulich School of Engineering University of Calgary 2500 University Drive NW Calgary Alberta T2N 1N4 Canada Department of Chemistry Faculty of Science University of Calgary 2500 University Drive NW Calgary Alberta T2N 1N4 Canada Present address: Institute for Resources Environment and Sustainability University of British Columbia 2202 Main Hall Vancourer BC V6T 1Z4 Canada

The degradation of benzene, a carcinogenic air pollutant, was studied in a gas-phase photochemical reactor with an amalgam lamp emitting ultraviolet light at 185 and 254 nm. Efficient benzene degradation （〉70%） was possible for benzene mass flow rates of up to 1.5 ***1. Adding ozone allowed benzene mass flow rates of up to 5 m ***-1 tobe treated with the same efficiency. In terms of energy consumption, ozone doubles the efficiency of the process. A comprenenslve mecnanisnc simulation model was developed incorporating a chemical kinetics model （62 reactions involving 47 chemical species）, a material balance model incorporating diffusion and flow, a flow velocity model,and a light field model. The model successfully predicted the efficiency of the reactor, generally within 20%, which indicates that the model is sound, and can be used for feasibility studies. The prediction of the reactor efficiency in the presence of ozone was less successful, with systematically overestimated efficiency. Condensation of reaction products in the reactor is thought to be the mare cause of model inaccuracy. Both experimental .data and model predictions show that there is a synergistic effect between ozonation and ultraviolet degradation.

关键词： Photolysis OzoneBenzene Waste gas Simulation Synergism

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Cobalt（Ⅲ） Complex [CoL3] Derived from an Asymmetric Bidentate Schiff Base Ligand L （L=（5-Bromo-2- hydroxybenzyl-2-furylmethyl）-imine）： Synthesis, Characterization and Crystal Structure

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Chinese Journal of Chemistry 2011年第8期29卷 1613-1616页

作者： Khalaji, Aliakbar D. Maghsodlou Rad, Sepideh Grivani, Gholamhossein rezaei, Morteza Gotoh, Kazuma Ishida, Hiroyuki Department of Chemistry Faculty of Science Golestan University Gorgan Iran School of Chemistry Damghan University Damghan P. O. Box 36715-364 Iran Department of Chemistry Faculty of Science Okayama University Okayama 700-8530 Japan

Cobalt（Ⅲ） complex [CoL3], where L=（5-bromo-2-hydroxybenzyl-2-furylmethyl）imine, has been synthesized by reacting cobalt（Ⅱ） nitrate with L. The complex has been characterized by elemental analysis and FT-IR spectroscopy. The crystal structure of [CoL3]_was determined by X-ray crystallography from single crystal data. It crys- tallizes in the triclinic space group P1 with unit cell parameters： a=9.6644（10）A, b--11.5657（11）A, c= 16.5809（17）A, a= 102.833（4）°,β= 102.999（3）°, γ= 105.480（3）°, V= 1659.9（3）A3 and z=2. Thermal decomposition of [COL3] was studied by thermogravimetry in order to evaluate its thermal stability and thermal decomposition pathways.

关键词： Cobat(Ⅲ) spectroscopy crystal structure thermogravimetry

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幼龄仔猪利用日粮氨基酸的生化和生理学基础

幼龄仔猪利用日粮氨基酸的生化和生理学基础

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中国猪业发展大会

作者：陶莉何闪 rezaei R Wang W Wu z 江苏省农业委员会上海市农业科学院

蛋白质是猪日粮中数量上最昂贵的养分。因此,当务之急是要了解氨基酸在猪生长、发育、哺乳、繁殖和健康中的生理作用,以改善蛋白质营养,降低猪肉生产成本。由于人们对氨基酸的生化和营养作用了解不够,传统上认为新生、断奶后、生长-肥... 详细信息

蛋白质是猪日粮中数量上最昂贵的养分。因此,当务之急是要了解氨基酸在猪生长、发育、哺乳、繁殖和健康中的生理作用,以改善蛋白质营养,降低猪肉生产成本。由于人们对氨基酸的生化和营养作用了解不够,传统上认为新生、断奶后、生长-肥育和妊娠阶段的猪能合成足量的"营养性非必需氨基酸"(Nutritionally Nonessential Amino Acid,NEAA),以维持其最大的生产性能。因此,在过去50年中,人们将更多的关注放在作为组织蛋白组成成分的NEAA的需求上。然而,大量的文献资料表明,NEAA,特别是谷氨酰胺、谷氨酸、精氨酸、脯氨酸,能通过细胞信号通路调节动物机体的生理功能,如雷帕霉素的哺乳动物目标、AMP激活的蛋白激酶、与细胞外信号相关的激酶、Jun激酶、丝裂原活化蛋白激酶、源自NEAA的气体分子(如氧化氮、一氧化碳、氢化硫)。有证据表明,在现有的饲喂方案中,只有70%和55%的日粮氨基酸被作为组织蛋白分别会在母猪哺乳的14日龄仔猪和21日龄断奶的30日龄仔猪体内沉积。因此。急需了解NEAA在猪营养中的作用和日粮需求。本文将重点探讨氨基酸在幼龄仔猪体内吸收和利用的生化和生理原理,以提高猪对日粮蛋白质的利用效力,并尽量减少含氮废物的排泄。

关键词：氨基酸新陈代谢营养猪

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