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Novel Nanostructured mnO_2 Prepared by Pulse Electrodeposition:Characterization and Electrokinetics

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Journal of materials Science & Technology 2008年第6期24卷 857-862页

作者： h.Adelkhani m.Ghaemi S.m.Jafari Department of Chemistry School of SciencesTarbiat Modares UniversityP.O.Box 14115-175TehranIran Department of Chemistry Science FacultyGolestan UniversityP.O.Box 49138-15739GorganIran Department of mathematics Science FacultyGolestan UniversityGorganIran

Pulse current technique was applied for the preparation of novel electroactive manganese dioxide and possible influences of different electrokinetic phenomena on material characteristics were discussed. The characterizations of pulse deposited sample （pcmD） were carried out by different techniques： Fourier transform infrared spectroscopy （FTIR）, scanning electron microscopy （SEm）, X-ray diffraction （XRD）, Brunauer-Emmett-Teller （BET） method, Raman spectroscopy, and atomic force microscopy （AFm）. SEm image revealed that pulse current could improve the current distribution. This was confirmed by AFm images showing a decrease in surface roughness of pcmDs in comparison to amorphous samples, which were deposited by direct current （dcmD）. higher distortion of mnO6 octahedral environment of dcmD was detected by FTJR and Raman spectroscopy. Cyclic voltammetric （CV） measurements showed a generally higher energy level drained from the second electron discharge of pcmD. This is mainly attributed to a higher surface area and a lower diffusion pass of electrons and protons arisen via a rather unique nanostructural arrangement of pcmD grains. Results indicate a higher surface area available for the non homogenous second electron discharge of pcmD grains.

关键词： manganese dioxide Pulse electrodeposition Nano-structures Electrocrystallization

Effect of ECAP temperature on microstructure and mechanical properties of Al–Zn–mg–Cu alloy

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Progress in Natural Science:materials International 2016年第2期26卷 182-191页

作者： m.h.Shaeri m.Shaeri m.Ebrahimi m.T.Salehi S.h Seyyedein Department of metallurgy and materials Engineering Engineering Faculty Imam Khomeini International University Department of materials Science and Engineering Sharif University of Technology Department of mechanical Engineering University of Maragheh Department of metallurgy and materials Engineering Iran University of Science and Technology

The effect of equal channel angular pressing(ECAP) at different temperatures(room temperature, 120,150 and 180 °C) on microstructure and mechanical properties of Al-7075 solid solution alloy was investigated. microstructure of the specimens was examined using orientation imaging microscopy,transmission electron microscopy as well as X-ray diffractometer, and mechanical properties were measured by Vickers microhardness and tensile tests. microstructural investigations showed that after3 or 4 passes of ECAP, fi ne grains with average grain sizes in range of 300–1000 nm could be obtained at different ECAP temperatures. Increasing ECAP temperature from 120 to 180 °C caused a decrease in mechanical properties as a result of increasing grains and precipitates sizes, decreasing fraction of high angle boundaries and also transformation of η′ into η phase, while increasing ECAP temperature from RT to 120 °C leads to an increase in mechanical properties due to the formation of small η′ precipitates. So it can be concluded that ECAP process at 120 °C is the optimum process for attaining maximum mechanical properties. Quantitative estimates of various strengthening mechanisms revealed that the improvement of mechanical properties was mainly attributed to grain re fi nement strengthening, precipitation strengthening and dislocation strengthening.

关键词： Equal channel angular pressing microstructure Strengthening mechanisms mechanical properties

Three-dimensional free vibration analysis of multi-directional functionally graded piezoelectric annular plates on elastic foundations via state space based differential quadrature method

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Applied mathematics and mechanics(English Edition) 2015年第4期36卷 439-464页

作者： m.h.YAS N.mOLOUDI Department of mechanical Engineering Razi University

The three-dimensional free vibration analysis of a multi-directional func- tionally graded piezoelectric （FGP） annular plate resting on two parameter （Pasternak） elastic foundations is investigated under different boundary conditions. The material properties are assumed to vary continuously along the radial and thickness directions and have exponent-law distribution. A semi-analytical approach named the state space based differential quadrature method （SSDQm） is used to provide an analytical solution along the thickness using the state space method （SSm） and an approximate solution along the radial direction using the one-dimensional differential quadrature method （DQm）. The influence of the Winkler and shear stiffness of the foundation~ the material property graded variations, and the circumferential wave number on the nomdimensional natural frequency of multi-directional FGP annular plates is studied.

关键词： multi-directional functionally graded piezoelectric annular plate freevibration

Conceptual exploration of a gravity-assisted electrorheological fluid-based gripping methodology for assistive technology

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Bio-Design and manufacturing 2019年第3期2卷 145-152页

作者： Ivo Radice Jeroen h.m.Bergmann Department of Engineering Science Old Road Campus Research BuildingInstitute of Biomedical EngineeringUniversity of OxfordHeadingtonOxfordUK

Gripping devices help patients carry out everyday tasks and increase their ***,there seems to be a lack of bionic gripping technologies that can fully adapt to any possible shape,as the use of artificial fingers and predetermined grip settings limits the operating *** development of a more agile device,which is operated by a simple control paradigm,could greatly benefit *** electrorheological(ER)fluid system should be able to adapt to the shape of an object and then hold that *** aim of this study was to explore if a conceptual prototype of an ER system could hold a geometric shape when it is activated.A test rig was constructed with a moving part(set in different silicone oils)that could be displaced using a *** particles were dispersed in the silicone oils,and a field with a voltage of 4 kV mm?1 was generated to activate the *** results show that the developed system can support an increased force when activated and hold a simple geometric position without any noticeable *** outcome provides an initial proof of concept for a possible new(gravity-assisted)gripping approach using smart fluids,which could be developed with materials that are biocompatible and widely available.

关键词： Smart materials Prosthetics Exoskeleton Grasping manipulation Assistive technologies

Entropy squeezing and atomic inversion in the K-photon Jaynes–Cummings model in the presence of the Stark shift and a Kerr medium:A full nonlinear approach

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Chinese Physics B 2014年第7期23卷 417-428页

作者： h R Baghshahi m K Tavassoly A Behjat Atomic and molecular Group Faculty of PhysicsYazd University The Laboratory of Quantum Information Processing Yazd University Department of Physics Faculty of ScienceVali-e-Asr University of Rafsanjan Photonics Research Group Engineering Research CenterYazd University

The interaction between a two-level atom and a single-mode field in the k-photon Jaynes-Cummings model （JCm） in the presence of the Stark shift and a Kerr medium is studied. All terms in the hamiltonian, such as the single-mode field, its interaction with the atom, the contribution of the Stark shift and the Kerr medium effects are considered to be f-deformed. In particular, the effect of the initial state of the radiation field on the dynamical evolution of some physical properties such as atomic inversion and entropy squeezing are investigated by considering different initial field states （coherent, squeezed and thermal states）.

关键词： Jaynes-Cummings model entropy squeezing atomic inversion intensity-dependent coupling

Seismic assessment of unanchored steel storage tanks by endurance time method

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Earthquake Engineering and Engineering Vibration 2011年第4期10卷 591-603页

作者： m. Alembagheri h.E. Estekanchi Department of Civil Engineering Sharif University of Technology (SUT)

Liquid storage tanks are essential structures that are often located in residential and industrial areas; thus an assessment of their seismic performance is an important engineering issue. In this paper, the seismic response ofunanchored steel liquid storage tanks is investigated using the endurance time （ET） dynamic analysis procedure and compared to responses obtained for anchored tanks under actual ground motions and intensifying ET records. In most cases, the results from ground motions are properly obtained with negligible differences using ET records. It is observed that uplifting of the tank base, which is closely related to the tank aspect ratio, has the greatest significance in the responses of the tank and can be predicted with reasonable accuracy by using currently available ET records.

关键词： steel liquid storage tanks endurance time method seismic assessment intensifying dynamic excitation tank base uplifting

modeling and Simulation of microstructurally Small Crack Formation and Growth in Notched Nickel-base Superalloy Component

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Journal of materials Science & Technology 2014年第3期30卷 203-212页

作者： G.m.Owolabi h.A.Whitworth Department of mechanical Engineering Howard University

Studies on microstructurally small fatigue cracks have illustrated that heterogeneous microstructural features such as inclusions, pores, grain size distribution as well as precipitate size distribution and volume fraction create stochasticity in their behavior under cyclic loads. Therefore, to enhance safe-life and damage-tolerance approaches, accurate modeling of the influence of these heterogeneous microstructural features on microstructurally small crack formation and growth from stress raisers is necessary. In this work, computational micromechanics was used to predict the high cycle fatigue of microstructurally small crack formation and growth in notched polycrystalline nickel-base superalloys and to quantify the variability in the driving force for formation and growth of microstructurally small crack from notch root in the matrix with non-metallic inclusions. The framework involves computational modeling to obtain three-dimensional perspectives of microstructural features influencing fatigue crack growth in notched nickel-base superalloys, which accounts for the effects of nonlocal notch root plasticity, loading, microstructural variability, and extrinsic defects on local cyclic plasticity at the microstructure-scale level. This approach can be used to explore sensitivity of minimum fatigue lifetime to microstructures. The simulation results obtained from this framework were calibrated to existing experimental results for polycrystalline nickel-base superalloys.

关键词： microstructuraliy small crack Crystal plasticity Nickel-base superalloy Fatigue life

Rice (Oryza sativa L.) nutrient management using mycorrhizal fungi and endophytic herbaspirillum seropedicae

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Journal of Integrative Agriculture 2016年第6期15卷 1385-1394页

作者： h hoseinzade m R Ardakani A Shahdi h Asadi Rahmani G Noormohammadi m miransari Department of Agronomy Science and Research Branch Islamic Azad University Tehran *** Iran Department of Agronomy Islamic Azad University Karaj branch 86319615 Iran Rice Research Institute of Iran Rasht 43114843 Iran Soil and Water Research Institute Karaj 394923973 Iran Department of Book&Article Abtin Berkeh L td Company Isfahan *** Iran

Integrated nutrient management with biological and chemical fertilizers can improve rice （Oryza safiva L.） productivity, bio-fortification, soil health and fertility. Accordingly, this study was planned to evaluate the combined effects of biological fertilizers including arbuscular mycorrhizal （Am） fungi （Glomus mosseae） and free-living nitrogen-fixing bacteria （herbaspi- rillum seropedicae）, as well as chemical fertilizers on the yield and nutrient contents of wetland rice under field conditions. Seedlings were inoculated with Am fungi and the bacteria in the nursery and were then transplanted to the field. The experi- ment was carried out as a split factorial design with three replicates. Treatments included three rates of nitrogen （N 1, N2 and N3） and phosphorous （P1, P2 and P3） fertilizers （100, 75 and 50% of the optimum level） in the main plots and mycorrhizal and bacterial treatments in the sub plots. The total of urea （g） used per plot was equal to N1=200, N2=150 and N3=100 at three different growth stages （seeding, tillering and heading） and the total of P （g） per plot used once at seeding using triple super phosphate including P1 =16, P2=13 and P3=10. Plant growth and yield as well as the concentration of nitrogen （N）, phosphorous （P）, potassium （K）, iron （Fe）, and zinc （Zn） were measured in the soil, straw and grains. N-fertilizer and biological fertilizers had significant effects on root, shoot and grain yield of rice, however, P-fertilizer just significantly affected root and shoot dry weights. Interestingly, analyses of variance indicated that biological fertilization significantly affected all the experimental treatments except straw N. Am fungi, N1 and P1 resulted in the highest rate of rice growth and yield. The interactions of chemical and biological fertilization resulted in significant effects on grain Zn, Fe, P, and N as well as soil Fe, K and N. The highest rate of grain nutrient uptake was resulted by the combined use of biological fertilizatio

关键词： bio-fortification nutrient management yield biological fertilizer rice (Oryza sativa L.)

Landau damping in a dipolar Bose–Fermi mixture in the Bose–Einstein condensation(BEC) limit

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Chinese Physics B 2016年第12期25卷 367-376页

作者： S m moniri h Yavari E Darsheshdar Department of Physics University of Isfahan

By using a mean-field approximation which describes the coupled oscillations of condensate and noncondensate atoms in the collisionless regime, Landau damping in a dilute dipolar Bose-Fermi mixture in the BEC limit where Fermi superfluid is treated as tightly bounded molecules, is investigated. In the case of a uniform quasi-two-dimensional （2D） case, the results for the Landau damping due to the Bose-Fermi interaction are obtained at low and high temperatures. It is shown that at low temperatures, the Landau damping rate is exponentially suppressed. By increasing the strength of dipolar interaction, and the energy of boson quasiparticles, Landau damping is suppressed over a broader temperature range.

关键词： Landau damping mixtures of Bose and Fermi superfluids dipole-dipole interaction