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Gamma-ray shielding properties of concrete with different percentages of lead

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Nuclear Science and Techniques 2012年第4期23卷 215-218页

作者： d.rezaei-ochbelagh S.Azimkhani H. Gasemzadeh Mosavinejad department of Physics Faculty of Sciences University of Mohaghegh ArdabiliP.O.Box 179ArdebilIslamic Republic of Iran department of Civil Engineering Engineering Faculty the University of GuilanRashtIslamic Republic of lran

In this work,concrete with different percentage leads was used to study gamma-ray shielding properties. The gamma-rays from ^(137)Cs and ^(60)Co sources were detected by Nal(Tl) detector and analyzed by multi-analyzer. Linear attenuation coefficients and compressive strength(kg/cm2) of concrete specimens were *** show that the concrete at the 90% weight ratio of lead to cement can be suitable for shielding gamma-ray.

关键词：混凝土试件屏蔽性能 γ-射线铅射线检测抗压强度分析仪探测器

In Situ Mineralization of Biomass-derived Hydrogels Boosts Capacitive Electrochemical Energy Storage in Free-Standing 3d Carbon Aerogels

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Energy & Environmental Materials 2024年第2期7卷 359-371页

作者： Anjali Achazhiyath Edathil Babak rezaei Kristoffer Almdal Stephan Sylνest Keller National Centre for Nano Fabrication and Characterization DTU NanolabTechnical University of Denmark2800LyngbyDenmark dTU Chemistry Technical University of Denmark2800LyngbyDenmark

Here,a novel fabrication method for making free-standing 3d hierarchical porous carbon aerogels from molecularly engineered biomass-derived hydrogels is *** situ formed flower-like CaCO_(3)molecularly embedded within the hydrogel network regulated the pore structure during in situ mineralization assisted one-step activation graphitization(iMAG),while the intrinsic structural integrity of the carbon aerogels was *** homogenously distributed minerals simultaneously acted as a hard template,activating agent,and graphitization *** decomposition of the homogenously distributed CaCO_(3)during iMAG followed by the etching of residual CaO through a mild acid washing endowed a robust carbon aerogel with high porosity and excellent electrochemical *** 0.5 mA cm^(-2),the gravimetric capacitance increased from 0.01 F g^(-1)without mineralization to 322 F g^(-1)with iMAG,which exceeds values reported for any other free-standing or powder-based biomass-derived carbon *** outstanding cycling stability of~104%after 1000 cycles in 1 M HClO4 was *** assembled symmetric supercapacitor device delivered a high specific capacitance of 376 F g^(-1)and a high energy density of 26 W h kg^(-1)at a power density of 4000 W kg^(-1),with excellent cycling performance(98.5%retention after 2000 cycles).In combination with the proposed 3d printed mold-assisted solution casting(3dMASC),iMAG allows for the generation of free-standing carbon aerogel architectures with arbitrary ***,the novel method introduces flexibility in constructing free-standing carbon aerogels from any ionically cross-linkable biopolymer while maintaining the ability to tailor the design,dimensions,and pore size distribution for specific energy storage applications.

关键词： biomass carbon aerogel sustainable energy materials free-standing supercapacitors

Theoretical Study of 13C Chemical Shifts Structures of Some ortho-Substituted 3-Anilino-2-nitrobenzo[b]thiophenes and 2-Anilino-3-nitrobenzo[b]thiophenes and Comparison with Experimental

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Chinese Journal of Chemistry 2011年第2期29卷 237-242页

作者： Mahdi rezaei Sameti department of Physical Chemistry Faculty of Science Malayer University Malayer 65157 Iran

13C NMR chemical shifts have been calculated for structures of some substituted 3-anilino-2-nitrobenzo- [b]thiophenes （2o） and 2-anilino-3-nitrobenzo[b]thiophenes （3o） derivatives containing OH, NH2, OMe, Me, Et, H, F, Cl and Br. The molecular structures were fully optimized using B3LYP/6-31G（d,p）. The calculation of the 13C shielding tensors employed the GAUSSIAN 03 implementation of the gauge-including atomic orbital （GIAO） and continuous set of gauge transformations （CSGT） by using 6-311 ＋＋G（d,p） basis set at density functional levels of theories （dFT）. The isotropic and the anisotropy parameters of chemical shielding for all compounds are calculated. The predicted 13C chemical shifts are derived from equation δ=σ0＋σ where δ is the chemical shift, σ is the absolute shielding, and σ0 is the absolute shielding of the standard TMS. Excellent linear relationships have been observed between experimental and calculated 13C NMR chemical shifts for all derivatives.

关键词： dPT 13C NMR chemical shifts GIAO/CSGT

Energy level splitting of a 2d hydrogen atom with Rashba coupling in non-commutative space

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Communications in Theoretical Physics 2020年第12期72卷 116-122页

作者： S Aghababaei G rezaei department of Physics College of SciencesYasouj UniversityYasouj75918-74934Iran

We explore the non-commutative(NC)effects on the energy spectrum of a two-dimensional hydrogen *** consider a confined particle in a central potential and study the modified energy states of the hydrogen atom in both coordinates and momenta of non-commutativity *** considering the Rashba interaction,we observe that the degeneracy of states can also be removed due to the spin of the particle in the presence of NC *** obtain the upper bounds for both coordinates and momenta versions of NC parameters by the splitting of the energy levels in the hydrogen atom with Rashba ***,we find a connection between the NC parameters and Lorentz violation parameters with the Rashba interaction.

关键词： quantum mechanics non-commutative space spin–orbit interaction

distributed output feedback stationary consensus of multi-vehicle systems in unknown environments

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Control Theory and Technology 2018年第2期16卷 93-109页

作者： Vahid.rezaei Margareta STEFANOVIC department of Electrical and Computer Engineering University of Denver Denver CO 80208 U.S.A.

In the traditional distributed consensus of multi-vehicle systems, vehicles agree on velocity and position using limited information exchange in their local neighborhoods. Recently, distributed leaderless stationary consensus has been proposed in which vehicles agree on a position and come to a stop. The proposed stationary consensus schemes are based on all vehicles＇ access to their own absolute velocity measurements, and they do not guarantee this collective behavior in the presence of disturbances that persistently excite vehicles＇ dynamics. On the other hand, traditional distributed disturbance rejection leaderless consensus algorithms may result in an uncontrolled increase in the speed of multi-vehicle system. In this paper, we propose a dynamic relative-output feedback leaderless stationary algorithm in which only a few vehicles have access to their absolute measurements. We systematically design the distributed algorithm by transforming this problem into a static feedback robust control design challenge for the low-order modified model of vehicles with fictitious modeling uncertainties. We further propose dynamic leader-follower stationary consensus algorithms for multi-vehicle systems with a static leader, and find closed-form solutions for the consensus gains based on design matrices and communication graph topology. Finally, we verify the feasibility of these ideas through simulation studies.

关键词： Multi-vehicle system distributed control stationary consensus disturbance accommodation

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

Preparation of nanocrystalline γ-Al_2O_3 catalyst using different procedures for methanol dehydration to dimethyl ether

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Journal of Natural Gas Chemistry 2011年第3期20卷 334-338页

作者： Ahmad Reza Keshavarz Mehran rezaei Fereydoon Yaripour Catalyst and Advanced Materials Research Laboratory Chemical Engineering Department Faculty of Engineering University of Kashan Institute of Nanoscience and Nanotechnology University of Kashan Catalyst Research Group Petrochemical Research & Technology Company National Petrochemical Company (NPC)

A series of nanocrystalline γ-alumina are synthesized by different procedures, namely, thermal decomposition method （sample A）, precipita-tion method （sample B） and sol-gel method using sucrose and hexadecyltrimethyl ammonium bromide （CTAB） as templates （samples C and d, respectively）. Textural and acidic properties of γ-alumina samples are characterized by XRd, N2 adsorption-desorption and NH3-TPd techniques. Vapor-phase dehydration of methanol into dimethyl ether is carried out over these samples. Among them, sample C shows the highest catalytic activity. NH3-TPd analysis reveals that the sample with smaller crystallite size possesses higher concentration of medium acidic sites and consequently higher catalytic activity. Thermal decomposition method leads to decrease in both surface area and moderate acidity, therefore it is the cause of lower catalytic activity.

关键词： methanol dehydration dimethyl ether gama alumina sol-gel

Energy supply for water electrolysis systems using wind and solar energy to produce hydrogen: a case study of Iran

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Frontiers in Energy 2019年第3期13卷 539-550页

作者： Mostafa rezaei Ali MOSTAFAEIPOUR Mojtaba QOLIPOUR Mozhgan MOMENI Industrial Engineering department Yazd UniversityYazd ***Iran

due to acute problems caused by fossil fuels that threaten the environment, conducting research on other types of energy carriers that are clean and renewable is of great importance. Since in the past few years hydrogen has been introduced as the future fuel, the aim of this study is to evaluate wind and solar energy potentials in prone areas of Iran by the Weibull distribution function (WdF) and the Angstrom-Prescott (AP) equation for hydrogen production. To this end, the meteorological data of solar radiation and wind speed recorded at 10 m height in the time interval of 3 h in a five-year period have been used. The findings indicate that Manjil and Zahedan with yearly wind and solar energy densities of 6004 (kWh/m2) and 2247 0cWh/m2), respectively, have the greatest amount of energy among the other cities. After examining three different types of commercial wind turbines and photovoltaic (PV) systems, it becomes clear that by utilizing one set of Gamesa G47 turbine, 91 kg/d of hydrogen, which provides energy for 91 car/week, can be produced in Manjil and will save about 1347 L of gasoline in the week. Besides, by installing one thousand sets of X21-345 PV systems in Zahedan, 20 kg/d of hydrogen, enough for 20 cars per week, can be generated and 296 L of gasoline can be saved. Finally, the RETScreen software is used to calculate the annual CO2 emission reduction after replacing gasoline with the produced hydrogen.

关键词： wind energy solar energy water electrolysis hydrogen production Weibull distribution function (WdF) Angstrom丒Prescott (AP) equation

dietary supplementation with branchedchain amino acids enhances milk production by lactating sows and the growth of suckling piglets

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Journal of Animal Science and Biotechnology 2022年第6期13卷 1857-1870页

作者： Reza rezaei Ana San Gabriel Guoyao Wu department of Animal Science Texas A&M UniversityCollege StationTX 77843USA Ajinomoto Co. Inc1-15-1 KyobashiChuokuTokyo 104-8315Japan

Background:Under current dietary regimens,milk production by lactating sows is insufficient to sustain the maximal growth of their *** precursors of glutamate and glutamine as well as substrates and activators of protein synthesis,branched-chain amino acids(BCAAs)have great potential for enhancing milk production by ***:Thirty multiparous sows were assigned randomly into one of three groups:control(a corn-and soybean meal-based diet),the basal diet+1.535%BCAAs;and the basal diet+3.07%*** ratio(g/g)among the supplemental L-isoleucine,L-leucine and L-valine was 1.00:2.56:*** were made isonitrogenous by the addition of appropriate amounts of *** sows had free access to drinking water and their respective *** number of live-born piglets was standardized to 9 per sow at d 0 of lactation(the day of parturition).On d 3,15 and 29 of lactation,body weights and milk consumption of piglets were measured,and blood samples were obtained from sows and piglets 2 h and 1 h after feeding and nursing,***:Feed intake did not differ among the three groups of *** of asparagine,glutamate,glutamine,citrulline,arginine,proline,BCAAs,and many other amino acids were greater(Pd sows and their piglets than those in the control *** with the control,dietary supplementation with 1.535%and 3.07%BCAAs increased(Pd protein-bound BCAAs,glutamate plus glutamine,aspartate plus asparagine,and many other amino acids in milk;milk production by 14%and 21%,respectively;daily weight gains of piglets by 19%and 28%,respectively,while reducing preweaning mortality rates by 50%and 70%,***:dietary supplementation with up to 3.07%BCAAs enhanced milk production by lactating sows,and the growth and survival of their piglets.

关键词： Branched-chain amino acids Lactation Milk synthesis Milk yield Neonatal growth Sow