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Structural,Dielectric and Complex Impedance Spectroscopy Studies of Lead Free Ca_(0.5+x)Nd_(0.5-x)(Ti_(0.5)Fe_(0.5))O_3

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Journal of materials Science & Technology 2013年第4期29卷 323-329页

作者： m.r.Shah A.K.m.Akther Hossain Department of Physics University of PrimeasiaBananiDhaka 1213Bangladesh Department of Physics Bangladesh University of Engineering and TechnologyDhaka 1000Bangladesh

Structural and various electrical properties of polycrystalline Ca0.5＋xNd0,5-x（Ti0.5Fe0.5）O3, prepared by standard solid state reaction technique, were studied. Formation of single phase orthorhombic structure of the compositions was confirmed by X-ray diffraction study. The composition dependence of lattice parameters, density and microstructural study show that they vary significantly with Ca content. The dielectric measurements were carried out at room temperature as function of frequency and composition. The experimental results reveal that the dielectric constant （ε′） increases with increasing Ca content. Similar behavior is observed for the dielectric loss （tanδ） and ac conductivity （σac）. In complex impedance analysis it is observed that the real part （Z′） vs imaginary part （Z″） graph exhibits a tendency of formation of a single semicircular arc for each composition of samples. Different parameters were determined by fitting the experimental data in Cole-Cole empirical formula. A dominance of grain boundary resistance （rgb） is observed. The rgb decreases with increasing Ca content. The high ε′ observed in present samples are suitable for fabrication of devices.

关键词： Crystal structure Dielectric properties Lead free Perovskite Solid state reaction

Influence of Aluminum Content on mechanical Properties and Cold Workability of Fe-33Ni-15Co Alloy

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Journal of Iron and Steel research International 2012年第2期19卷 67-72页

作者： m Safavi S m Abbasi r mahdavi Department of materials Science and Engineering Semnan University Advanced materials research Laboratory (AmrL) Department of Mechanical Engineering K.N. Toosi University of Technology Department of materials Science Azad University

The influence of 0.01% to 0. 25% of Aluminum content （in mass percent） on the mechanical properties and cold workability of low thermal expansion Fe-33Ni-15Co sheets in the annealed and hot rolled condition was investigated. Addition of Al up to 0.15 % resulted in the increase of ductility and tougianess and improvement of workability. Besides, achievement of fine grain structure and increase in the amount of annealing twins caused ductility to improve. Addition of Al higher than 0.15 % led to the increase in oxidation reaction during melting process and to refine under argon atmosphere. This caused the volume fraction of Al containing inclusions to increase and consequently the ductility and toughness to decrease.

关键词： Fe-33Ni-15Co alloy A1 content mechanical property cold workability

Analysis of Differences in Productivity,Profitability and Soil Fertility Between Organic and Conventional Cropping Systems in the Tropics and Sub-tropics

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Journal of Integrative Agriculture 2014年第10期13卷 2299-2310页

作者： Te Pas C m rees r m School of GeoSciences University of Edinburgh Carbon management Centre Scotland's Rural College

Organic farming aims to stimulate soil fertility by avoiding the use of synthetic fertiliser inputs, relying instead on locally available natural resources. It is regarded by many as a sustainable alternative to conventional fanning because it ensures higher biodiversity, restricts environmental pollution, prevents land degradation and is easy to apply for smallholder and subsistence farmers. Although widely practiced and studied in temperate regions, little is known about the potential overall benefits of organic farming in the tropics and subtropics. This paper addresses this gap by undertaking an analysis of the differences between organic and conventional agriculture in the tropics and sub-tropics based on an extensive literature review including 88 papers with 458 data pairs. The comparison is based on three main indicators： yield, gross margin and soil organic carbon （SOC）. The differences between the organic and conventional systems for each of these main indicators is represented by the ratio of the value of the indicator in the organic system divided by the corresponding value in the conventional system. This was initially calculated for each data pair individually, and grouped by a variety of explanatory factors, such as precipitation, human development level, soil texture, crop type, organic input type, time after conversion and certification. The results demonstrate that under organic management, yields were on average 26% higher, gross margins 51% higher and soil organic carbon 53% higher than under conventional management. The highest yield increases in organic cropping systems were achieved in the least developed countries, in arid regions and on coarse soils. For gross margins, certification was the main reason for differences between organic and conventional systems. Certified farmers, mostly located in developed countries, receive significantly higher prices. Furthermore, organic farming in the driest regions results in higher profits than in other

关键词： organic farming conventional fanning tropics subtropics carbon sequestration yield soil quality soil organic carbon

Numerical Solution of Partial Differential Equations in Arbitrary Shaped Domains Using Cartesian Cut-Stencil Finite Difference *** II:Higher-Order Schemes

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Numerical mathematics(Theory,methods and Applications) 2022年第3期15卷 819-850页

作者： m.Esmaeilzadeh r.m.Barron Department of mechanical Automotive&Materials EngineeringUniversity of WindsorWindsorOntarioN9B 3P4Canada Department of mathematics&Statistics University of WindsorWindsorOntarioN9B 3P4Canada Department of mechanical Engineering South Tehran BranchIslamic Azad UniversityTehranP.C:***Iran

Compact higher-order(HO)schemes for a new finite difference method,referred to as the Cartesian cut-stencil FD method,for the numerical solution of the convection-diffusion equation in complex shaped domains have been addressed in this *** Cartesian cut-stencil FD method,which employs 1-D quadratic transformation functions to map a non-uniform(uncut or cut)physical stencil to a uniform computational stencil,can be combined with compact HO Pad´e-Hermitian formulations to produce HO cut-stencil *** modified partial differential equation technique is used to develop formulas for the local truncation error for the cut-stencil HO *** effect of various HO approximations for Neumann boundary conditions on the solution accuracy and global order of convergence are *** numerical results for second-order and compact HO formulations of the Cartesian cut-stencil FD method have been compared for test problems using the method of manufactured solutions.

关键词： Cartesian cut-stencil finite difference method compact higher-order formulation irregular domain Neumann boundary conditions local truncation error

Control system design for a pressure-tube-type supercritical water-cooled nuclear reactor via a higher order sliding mode method

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Nuclear Science and Techniques 2024年第1期35卷 145-154页

作者： m.Hajipour G.r.Ansarifar Department of Nuclear Engineering Faculty of PhysicsUniversity of IsfahanIsfahan 81746-73441Iran

Nuclear power plants exhibit non-linear and time-variable ***,designing a control system that sets the reactor power and forces it to follow the desired load is complicated.A supercritical water reactor(SCWr)is a fourth-generation conceptual *** an SCWr,the non-linear dynamics of the reactor require a controller capable of control-ling the *** this study,a pressure-tube-type SCWr was controlled during reactor power maneuvering with a higher order sliding mode,and the reactor outgoing steam temperature and pressure were controlled *** an SCWr,the temperature,pressure,and power must be maintained at a setpoint(desired value)during power *** point kinetics equations with three groups of delayed neutrons were used in the ***-order and classic sliding mode controllers were separately manufactured to control the plant and were compared with the PI controllers speci-fied in previous *** controlled parameters were reactor power,steam temperature,and ***,for these parameters,the PI controller had certain instabilities in the presence of *** classic sliding mode controller had a higher accuracy and stability;however its main drawback was the chattering *** was highly accurate and stable and had a small computational *** reality,it followed the desired values without oscillations and chattering.

关键词： Supercritical water nuclear reactor Higher order sliding mode controller Steam temperature Steam pressure Point kinetics model

Effects of mach numbers on magnus induced surface pressure

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Chinese Journal of Aeronautics 2020年第12期33卷 3058-3072页

作者： F.ASKArY m.r.SOLTANI Department of Aerospace Engineering Sharif UniversityTehran P.O.B ***Iran Department of Aeronautics and Astronautics University of WashingtonSeattle BOX 352400USA

Experimental and numerical methods were used to investigate the magnus phenomena over a spinning *** pressure force acting on the surface of a spinning projectile was measured for various cases by employing a relatively novel experimental technique.A set of miniature pressure sensors along with a data acquisition board,battery and storage memory were placed inside a spinning model and the surface pressure were obtained through a remotely controlled *** pressures of the model for both rotational and static conditions were obtained at two different free stream mach numbers of 0.4 and 0.8 and at different angles of *** results showed the ability of this new test method to measure the very small magnus force via surface pressures over the *** results provide a deep insight into the flow structure and illustrate changes in the cross-flow separation locations as a result of *** results were obtained by the numerical simulations and were compared with the experimental data.

关键词： magnus effect Spinning projectile Surface pressure Wind tunnel

Energy-based damage assessment of continuous-span reinforced concrete highway bridges

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Earthquake Engineering and Engineering Vibration 2023年第1期22卷 191-209页

作者： S.mahboubi m.r.Shiravand Faculty of Civil Water and Environmental EngineeringShahid Beheshti UniversityTehran ***Iran

This paper conducts a comparative study on seismic damage to reinforced concrete(rC)bridges,using three damage models:Park and Ang,Hindi and Sexsmith,and input energy-based damage(IEBD)indices,and presents a global cumulative damage model based on the IEBD index to establish a practical damage assessment of an overall bridge system.A series of rC bridges are studied under seismic loadings,and to compare the efficiency and reliability of the damage indices,damage curves of rC piers are developed,and damage levels of piers are calculated at design basis earthquake(DBE)and maximum considered earthquake(mCE)*** global cumulative damage index is calculated for bridge models regarding damage values of *** results indicate that the IEBD index shows a gradual progression of damage and provides reasonable values for different damage levels of piers compared to two other damage ***,the global cumulative damage index shows the impact of induced damage to a certain component regarding the damage level of the overall bridge ***,this new approach is a relatively simple and practical tool for seismic damage assessment of rC bridge systems,which can be implemented in finite element models,particularly in the absence of experimental data.

关键词： rC bridge energy-based damage index global cumulative damage index IEBD Index

Synthesis, spectral characterization, thermal and biological studies of lanthanide(Ⅲ) complexes of oxyphenbutazone

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Journal of rare Earths 2014年第1期32卷 43-51页

作者： P.S.Binil m.r.Anoop K.r.Jisha S.Suma m.r.Sudarsanakumar Department of Chemistry S.N.College Department of Chemistry M.G.College

Lanthanide（III） complexes of 4-butyl-1-（4-hydroxyphenyl）-2-phenyl-3,5-pyrazolidinedione （OPB） were prepared by ho-mogeneous precipitation. The solid complexes were characterized by elemental analysis, magnetic susceptibility data, molar conduc-tivity measurements and Ir, UV-Vis, mass, 1H Nmr and 13C Nmr spectral methods. The thermal decomposition of the complexes under static air atmosphere was investigated by simultaneous TG/DTG at a heating rate of 10 °C/min. The final decomposition prod-ucts were found to be metal oxides. The spectroscopic data suggested that OPB acted as a bidentate, mono-ionic ligand coordinating through two carbonyl oxygens of the pyrazolidinedione ring. The kinetic and thermodynamic parameters such as activation energy, pre-exponential factor and entropy of activation for each step of the decomposition reactions were evaluated using Coats-redfern and macCallum-Tanner equations. The negative entropy values of the complexes indicated that the activated complexes had a more or-dered structure than the reactant and that the reactions were slower than normal. Investigations of antimicrobial activity of the com-pounds were carried out by the disk diffusion technique.

关键词： oxyphenbutazone lanthanide(III) complexes thermal study antimicrobial activity rare earths

Synthesis and spectral characterization of lanthanide complexes with 1,2-diphenyl-4-butyl-3,5-pyrazolidinedione: Luminescent property of Tb(Ⅲ) complex

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Journal of rare Earths 2012年第7期30卷 709-715页

作者： m.r.Anoop P.S.Binil S.Suma m.r.Sudarsanakumar Department of Chemistry S.N. College Department of Chemistry S.N .College Depart-ment of Chemistry M.G. College

The complexes of rare earth elements with 1,2-diphenyl-4-butyl-3,5-Pyrazolidinedione （PBH, phenylbutazone） were synthesized and characterized by elemental analysis, molar conductance, Ir, UV-Vis, EPr and magnetic moment measurements. Based on these studies the complexes were formulated as [Ln（PB）3（H2O）2].nH2O, where Ln=Eu（III）, Gd（III）, Tb（III）, Dy（III） and Er（III）. From Ir spectra, it was found that PBH acted as a bidentate mono-ionic ligand coordinating through two carbonyl oxygen of the pyrazolidinedione ring. The thermal analysis of all the complexes was carried out at a heating rate of 10 oC/min. The kinetic aspects of the complexes were evaluated. The nega-tive entropy value of the complexes indicated a more ordered state for the activated complexes. The photoluminescence property of Tb（III） complex was investigated. It showed all the characteristic emission peaks of Tb^3＋ with a life time of 0.98914 ms.

关键词： lanthanide complexes Ir thermal analysis luminescent properties rare earths