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Microwave promoted rapid dehydration of aldoximes to nitriles using melamine-formaldehyde resin supported sulphuric acid in dry media

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Chinese Chemical Letters 2011年第7期22卷 815-818页

作者： Ramin rezaei Marzeih Karami Department of Chemistry Islamic Azad UniversityFirouzabad BranchP.O.Box 74715-117FirouzabadIran

A simple and convenient procedure for the synthesis of nitriles by dehydration of aldoxime using supported sulphuric acid on melamine-formaldehyde resin （MFR） under solvent-free condition has been developed. A variety of aromatic and aliphatic aldoximes were converted to the corresponding nitriles. The resin was recovered and reused for subsequent reactions. ~ 2011 Ramin rezaei. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

关键词： Aldoximes Nitriles Melamine-formaldehyde resin Sulphuric acid Solvent-free

Optimization of preparation conditions of Fe-Co nanoparticles in low-temperature CO oxidation reaction by taguchi design method

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Journal of Natural Gas Chemistry 2012年第4期21卷 415-420页

作者： Abolfazl Biabani Mehran rezaei Zohreh Fattah Catalyst and Advanced Materials Research Laboratory Chemical Engineering DepartmentFaculty of EngineeringUniversity of KashanKashan P.O.Box ***Iran Institute of Nanoscience and Nanotechnology University of KashanKashan P.O.Box ***Iran

Mixed iron-cobalt oxide （Co/Fe molar ratio = 1/5） are prepared using a simple co-precipitation procedure and studied for the catalytic oxidation of carbon monoxide. In particular, the effects of a range of preparation variables such as pH value when precipitation, aging temperature, precipitation agent type and aging time are investigated on the catalytic performance of synthesized Fe-Co oxides in CO oxidation reaction. In addition, the preparation factors were optimized by Taguchi design method. The optimized sample was characterized by XRD, N2 adsortion/desorption, TEM and TGA/DTA techniques. The results reveal that the optimized sample shows a mesoporous structure with a narrow pore size distribution centered in the range of 2-7 nm. The sample prepared under optimized conditions has high activity and stability toward removal of carbon monoxide at lower temperatures. It is shown that different preparation variables influence the catalytic performance of Fe-Co oxide in CO oxidation reaction.

关键词： Fe Co nanoparticles experimental design CO oxidation

Effect of Initial Grain Size on the Hot Deformation Behavior and Microstructural Evolution of Pure Copper

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Acta Metallurgica Sinica(English Letters) 2022年第4期35卷 662-678页

作者： H.R.rezaei Ashtiani A.A.Shayanpoor School of Mechanical Engineering Arak University of Technology38135-1177ArakIran

The influences of initial grain size(IGS)with 20μm and 50μm on the hot flow behavior and microstructural changes of pure copper were investigated using hot compression tests at a temperature range of 623–1073 K and strain rate range of 0.001–0.1 s^(-1).The effects of critical stress and corresponding critical strain were studied based on the internal and external processing *** critical stress and strain decreased with increasing temperature and decreasing strain *** investigation results of the microstructure and true strain–stress diagrams showed that dynamic recovery,dynamic recrystallization(DRX),and twinning mechanisms were caused during the hot deformation of pure *** evolution indicated some DRXed fine-grain took place around grain boundary of hot deformed samples with IGS of 20μm whereas DRXed fine-grain took place in interior grains for samples with larger *** results also showed that grain growth is also dependent on IGS as the grain growth rate for samples with the larger IGS is greater than the smaller *** critical strain rate and the temperature were obtained at 0.01 s^(-1) and 973 K,respectively,for the sudden change in the grain growth ***,twinning highly depended on IGS which almost did not happen in fine grain size while the volume fraction of twinning increased with increasing grain size.

关键词： Initial grain size Hot deformation Pure copper Microstructure Dynamic recrystallization(DRX) Twinning

Annual growth of Fagus orientalis is limited by spring drought conditions in Iran’s Golestan Province

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A novel frequency-selective metamaterial to improve helix antenna

林业研究（英文版） 2024年第1期 132页

作者： Khalil Ghorbani Jahangir Mohammadi Laleh rezaei Ghaleh

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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

Lossless multi-scale constitutive elastic relations with artificial intelligence

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npj Computational Materials 2022年第1期8卷 638-649页

作者： Jaber rezaei Mianroodi Shahed rezaei Nima H.Siboni Bai-Xiang Xu Dierk Raabe Microstructure Physics and Alloy Design Max-Planck-Institut für EisenforschungDüsseldorfGermany Ergodic Labs Lohmühlenstraße 6512435BerlinGermany Mechanics of Functional Materials Division Institute of Materials ScienceTechnische Universität DarmstadtDarmstadtGermany

A seamless and lossless transition of the constitutive description of the elastic response of materials between atomic and continuum scales has been so far *** we show how this problem can be overcome by using artificial intelligence(AI).A convolutional neural network(CNN)model is trained,by taking the structure image of a nanoporous material as input and the corresponding elasticity tensor,calculated from molecular statics(MS),as *** with the atomistic data,the CNN model captures the size-and pore-dependency of the material’s elastic properties which,on the physics side,derive from its intrinsic stiffness as well as from surface relaxation and non-local *** demonstrate the accuracy and the efficiency of the trained CNN model,a finite element method(FEM)-based result of an elastically deformed nanoporous beam equipped with the CNN as constitutive law is compared with that obtained by a full atomistic *** trained CNN model predicts the elasticity tensor in the test dataset with a root-mean-square error of 2.4 GPa(3.0%of the bulk modulus)when compared to atomistic *** the other hand,the CNN model is about 230 times faster than the MS calculation and does not require changing simulation methods between different *** efficiency of the CNN evaluation together with the preservation of important atomistic effects makes the trained model an effective atomistically informed constitutive model for macroscopic simulations of nanoporous materials,optimization of nanostructures,and the solution of inverse problems.

关键词： constitutive artificial elasticity

The effects of strong magnetic fields on neutron star structure:lowest order constrained variational calculations

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Research in Astronomy and Astrophysics 2013年第2期13卷 197-206页

作者： Gholam Hossein Bordbar Zeinab rezaei Department of Physics Shiraz University Center for Excellence in Astronomy and Astrophysics(CEAA-RIAAM)-Maragha

We investigate the effects of strong magnetic fields upon the large-scale properties of neutron and protoneutron stars. In our calculations, the neutron star mat- ter was approximated by pure neutron matter. Using the lowest order constrained vari- ational approach at zero and finite temperatures, and employing AV18 potential, we present the effects of strong magnetic fields on the gravitational mass, radius, and gravitational redshift of neutron and protoneutron stars. It is found that the equation of state for a neutron star becomes stiffer with an increase of magnetic field and tem- perature. This leads to larger values of the maximum mass and radius for the neutron stars.

关键词： dense matter -- equation of state -- stars magnetic fields -- stars fundamental parameters (masses, radii, temperatures)

Prenatal risk factors and genetic causes of ADHD in children

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World Journal of Pediatrics 2022年第5期18卷 308-319页

作者： Naghmeh Kian Noosha Samieefar Nima rezaei Student Research Committee School of MedicineShahid Beheshti University of Medical SciencesTehranIran Network of Interdisciplinarity in Neonates and Infants(NINI) Universal Scientific Education and Research Network(USERN)TehranIran USERN Office School of Advanced Technologies in MedicineShahid Beheshti University of Medical SciencesTehranIran Research Center for Immunodeficiencies Pediatrics Center of ExcellenceChildren's Medical CenterTehran University of Medical SciencesTehranIran

Background Attention deficit/hyperactivity disorder(ADHD)is a common disease among children;it affected 5-7% of the population in *** is a multifactorial disease,and its etiology is still not clearly *** Sources This narrative review has been done by searching the PubMed and Embase databases using attention deficit/hyperactivity disorder,ADHD,risk factors;genetics;pediatrics;psychiatrics as *** ADHD is considered to be a hereditary disorder in which genes play the fundamental role in the pathogenesis;however,findings from genetic-environmental studies support the hypothesis that genetic factors can exert effects on an indi-viduaFs condition by determining his/her responses to environmental exposures,especially those during the prenatal *** ADHD is considered as a hereditary disorder in which genes and prenatal risk factors play fundamental roles in the pathogenesis.

关键词： Attention deficit/hyperactivity disorder genetics Risk factors Pediatrics Psychiatrics

Selective methanation of carbon monoxide in hydrogen rich stream over Ni/CeO_2 nanocatalysts

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Journal of Rare Earths 2015年第6期33卷 619-628页

作者： Behzad Nematollahi Mehran rezaei Ebrahim Nemati Lay Catalyst and Advanced Materials Research Laboratory Chemical Engineering Department Faculty of Engineering University of Kashan Institute of Nanoscience and Nanotechnology University of Kashan

In the present work, selective methanation of carbon monoxide in hydrogen rich stream was investigated over Ni/CeO2 nanocatalysts. The obtained results revealed that increasing in nickel loading decreased the BET surface area, pore vohune and nickel dispersion. The 25%Ni/CeO2 with a NiO crystal size of 12 nm exhibited the highest activity in CO methanation reaction and reached to maximum CO conversion and CH4 selectivity at temperatures above 230 ℃. The catalytic results revealed that CO selective methanation well progressed at lower temperatures while CO2 methanation was completely suppressed until CO conversion reached to maximum value.

关键词： methanation nickel cerium oxide high surface area carbon monoxide rare earths