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Neural Regeneration Research 2014年第11期9卷 1108-1109页

作者： amir Paydar Center for Biomedical Imaging Department of Radiology New York University School of Medicine 660 First Ave4th Floor New York NY USA

Brain development is one of the most fascinating subjects in the field of biological sciences. Nonetheless, our scientific commu- nity still faces challenges in trying to understand the concepts that define the underlying mechanisms of neural tissue devel- opment. After all, it is a very complex subject to grasp and many of the processes that take place during central nervous system maturation are yet to be ascertained. Despite this challenge, we have come to recognize that understanding the natural course of normal brain tissue development on both microscopic and macroscopic scales is the key to deciphering the mechanisms through which these neural networks also heal and regenerate. Realizing this concept, my good friend and colleague, Dr. Sar- ah Milla, and I decided to take on a human study to investigate brain maturation using non-invasive imaging techniques in the pediatric population at New York University （NYU） School of Medicine （Paydar et al., 2013）. Our research subjects included 59 normal infants with an age spectrum ranging from birth to approximately 5 years of age, when the brain is in its most active stage of development. We implemented a Magnetic Resonance Imaging （MRI） diffusion technique called Diffusional Kurtosis Imaging （DKI） to investigate the microstructural changes that occur in both the white matter （WM） and gray matter （GM） in the developing brain.

关键词： Diffusional kurtosis imaging

Dependence of Nitrogen/Argon Reaction Gas Amount on Structural,Mechanical and Optical Properties of Thin WNx Films

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Chinese Physics Letters 2017年第12期34卷 56-60页

作者： Somayeh Asgary amir Hoshang Ramezani Department of Physics West Tehran BranchIslamic Azad UniversityTehranIran

WNxfilms are deposited by reactive chemical vapor deposition at different amounts of nitrogen in gas *** data demonstrate that nitrogen amount has a strong effect on microstructure, phase formation,texture morphology, mechanical and optical properties of the WNxfilms. With increasing nitrogen a phase transition from a single WNxphase with low crystallinity structure to a well-mixed crystallized hexagonal WNxand face-centered-cubic W2N phases appears. Relatively smooth morphology at lower N2concentration changes to a really smooth morphology and then granular with coarse surface at higher N2concentration. The SEM observation clearly shows a columnar structure at lower N2concentration and a dense nanoplates one for higher nitrogen content. The hardness of WNxthin films mainly depends on the film microstructure. The absorbance peak position shifts to shorter wavelength continuously with increasing nitrogen amount and decreasing particle size.

关键词： SEM Mechanical and Optical Properties of Thin WN_x Films Dependence of Nitrogen/Argon Reaction Gas Amount on Structural

Smoothed response spectra including soil-structure interaction effects

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Earthquake Engineering and Engineering Vibration 2020年第1期19卷 37-51页

作者： Farhad Behnamfar amir HBabaei Mehdi Ghandil Department of Civil Engineering Isfahan University of TechnologyIsfahan 841568311Iran Senior Structural Engineer TehranIran Department of Civil and Transportation Engineering University of IsfahanIsfahan ***Iran

Elastic response spectra that take into account the effects of soil-structure interaction on soft soils are developed. The response spectra are calculated utilizing a 3 DOF system including deformations of the superstructure and foundation. The equations of motion of the system are solved using direct integration under normalized earthquake records. Statistical processing of the results is implemented resulting in response spectra for "short and dense buildings with low interaction", "short and dense buildings with high interaction", "tall and light buildings with low interaction" and "tall and light buildings with high interaction". The resulting response spectra are smoothed and discussed.

关键词： response spectrum soil-structure interaction soft soil

Effect of alloying elements on austempered ductile iron(ADI) properties and its process:Review

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China Foundry 2015年第1期12卷 54-70页

作者： amir Sadighzadeh Benam University of Applied Science & Technology

Austempered ductile iron(ADI) parts have a unique combination of high strength and toughness with excellent design flexibility and low cost. These excellent properties are directly related to its microstructure called "ausferrite" that is the result of austempering heat treatment applied to ductile irons. Alloying elements increase ADI austemperability and change speeds of austempering reactions. Thus, they can affect ADI resultant microstructure and mechanical properties. In this paper, the effects of alloying elements on ADI mechanical properties, microstructural changes, two-stage austempering reactions, processing windows, austemperability, and other aspects are reviewed.

关键词： austempered ductile iron(ADI) alloying element processing window austemperability

Improvement of microstructure and corrosion properties of friction stir welded AA5754 by adding Zn interlayer

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International Journal of Minerals,Metallurgy and Materials 2018年第8期25卷 967-973页

作者： Ali Shamsipur amir Anvari Ahmad Keyvani Department of Mining and Metallurgical Engineering Amirkabir University of Technology School of Metallurgy and Materials Engineering Faculty of Technology and EngineeringShahrekord University

This study investigated the effect of Zn foil layers on the microstructure and corrosion characteristics of friction stir welded aluminum alloy *** of various joints were prepared by applying different rotational and welding speeds,and their microstructures were evaluated via a metallographic technique and scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy elemental *** anticorrosion behavior of joints in the absence and presence of a Zn interlayer was studied by cyclic potentiodynamic polarization test in 3.5 wt% Na Cl aqueous solution,and sound welds were obtained in the presence of the Zn interlayer *** results revealed that the joint made at a rotational speed of 800 r/min and traveling speed of 15 mm/min achieved a chemical composition identical to that of aluminum alloy 7 xxx series,and as such,it showed the best resistance to corrosion.

关键词： friction stir welding AA5754 aluminum alloy zinc interlayer microstructure corrosion resistance

Microstructural evolution and intermetallic formation in Al-8wt% Si-0.8wt% Fe alloy due to grain refiner and modifier additions

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International Journal of Minerals,Metallurgy and Materials 2012年第8期19卷 739-746页

作者： amir Hassani Khalil Ranjbar Sattar Sami Faculty of Materials Science and Engineering University of Semnan Semnan Iran Materials Department Faculty of Engineering Shahid Chamran University Ahwaz Iran

An alloy of A1-8wt% Si-0.8wt% Fe was cast in a metallic die, and its microstrucmral changes due to Ti-B refiner and Sr modifier additions were studied. Apart from usual refinement and modification of the microstructure, some mutual influences of the additives took place, and no mutual poisoning effects by these additives, in combined form, were observed. It was noticed that the dimensions of the iron-rich intermetallics were influenced by the additives causing them to become larger. The needle-shaped intermetallics that were obtained from refiner addition became thicker and longer when adding the modifier. It was also found that a-Al and eutectic silicon phases preferentially nucleate on different types of intermetallic compounds. The more iron content of the intermetallic compounds and the more changes in their dimensions occurred. Formation of the shrinkage porosities was also observed.

关键词： aluminum alloys metal casting grain refinement modification metallographic microstructure intermetallics

Resilient Fixed-Order Distributed Dynamic Output Feedback Load Frequency Control Design for Interconnected Multi-Area Power Systems

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IEEE/CAA Journal of Automatica Sinica 2019年第5期6卷 1139-1151页

作者： Ali Azarbahram amir Amini Mahdi Sojoodi the Department of Electrical and Computer Engineering Ferdowsi University of MashhadMashhadIran the Department of Electrical and Computer Engineering Concordia UniversityMontrealQCCanada the Faculty of Electrical and Computer Engineering Tarbiat Modares UniversityTehran14115-143Iran

The paper proposes a novel H∞ load frequency control(LFC) design method for multi-area power systems based on an integral-based non-fragile distributed fixed-order dynamic output feedback(DOF) tracking-regulator control scheme. To this end, we consider a nonlinear interconnected model for multiarea power systems which also include uncertainties and timevarying communication delays. The design procedure is formulated using semi-definite programming and linear matrix inequality(LMI) method. The solution of the proposed LMIs returns necessary parameters for the tracking controllers such that the impact of model uncertainty and load disturbances are minimized. The proposed controllers are capable of receiving all or part of subsystems information, whereas the outputs of each controller are local. These controllers are designed such that the resilient stability of the overall closed-loop system is guaranteed. Simulation results are provided to verify the effectiveness of the proposed scheme. Simulation results quantify that the distributed(and decentralized) controlled system behaves well in presence of large parameter perturbations and random disturbances on the power system.

关键词： Dynamic output feedback control interconnected multi-area power systems load frequency control linear matrix inequalities power system control

Effect of foundation flexibility on ductility reduction factors for R/C stack-like structures

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Earthquake Engineering and Engineering Vibration 2011年第2期10卷 277-290页

作者： amir M.Halabian Shabnam Kabiri Faculty of Civil Engineering Isfahan University of Technology

The most important parameter used to determine force reduction factors in force-based design procedures adopted in the current seismic codes is the structural ductility. For a structure supported on a flexible foundation, the ductility factor could be affected by foundation compliances. The ductility factors given in the current codes are mostly assigned ignoring the effect of SSI and therefore the objective of this research is to assess the significance of SSI phenomenon on ductility factors of stack-like structures. The deformed configuration of stack-fike structures is idealized as an assemblage of beam elements considering nonlinear moment-curvature relations, while a linear sway-rocking model was implemented to model the supporting soil. Using a set of artificial records, repeated linear and nonlinear analyses were performed by gradually increasing the intensity of acceleration to a level where the first yielding of steel in linear and nonlinear analyses is observed and a level corresponding to the stack collapse in the nonlinear analysis. The difference between inelastic and elastic resistance in terms of displacement ductility factors has been quantified. The results indicate that foundation flexibility can decrease the ductility of the system and neglecting this phenomenon may lead to erroneous conclusions in the prediction of the seismic performance of flexibly-supported R/C stack-like structures.

关键词： soil-structure interaction R/C stack-like structures ductility

Incidence and predictors of hypocalcemia in end-stage renal disease patients on denosumab therapy: A systematic review and metaanalysis

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World Journal of Meta-Analysis 2024年第3期12卷 68-78页

作者： Abdul Hannan Siddiqui Misbah Shaikh Afia Salman Muhammad Ahmed Ali Fahim Fizzah Batool Tahreem Mari Sarah Musani Muneeb Fareed Rooma Rehan Amna Hassni Urooj Nizami Ayesha amir Abdul Moeed Salim R Surani Department of Internal Medicine Dow University of Health SciencesKarachi 74200SindhPakistan Department of Medicine&Pharmacology Texas A&M UniversityCollege StationTX 77843United States

BACKGROUND Denosumab inhibits the receptor activator of nuclear factor *** markedly increases bone mineral density and has been proven to reduce the risk of ***,numerous adverse effects,notably hypocalcemia,are prevalent in patients with end-stage renal disease(ESRD).AIM To analyze the incidence and predictors of hypocalcemia caused by denosumab compared to control in patients with *** We conducted this study in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses ***,Scopus,Cochrane Central,and EMBASE were systematically searched from inception through March *** original studies investigating the effects of denosumab on patients with ESRD compared to control were *** primary outcomes of our study were the incidence of mild,severe,and very severe *** outcomes included serum levels of intact parathyroid hormone,calcium,and *** results were pooled and analyzed using a random-effects *** Seven articles comprising 3240 patients were included in our *** treated with denosumab had a significantly increased incidence of mild hypocalcemia[risk ratio(RR):2.79;95%confidence interval(CI):0.99-7.91;P=0.05;I^(2)=37%]and of very severe hypocalcemia(RR:9.58;95%CI:1.58-57.98;P=0.01;I^(2)=49%).However,an increase in the occurrence of severe hypocalcemia was non-significant(RR:4.23;95%CI:0.47-38.34;P=0.20;I^(2)=96%).Alternatively,denosumab showed a significant decrease in serum intact parathyroid hormone[mean difference(MD):-433.20,95%CI:-775.12 to-91.28,I2=98%,P=0.01],while there was a non-significant decrease in phosphate(MD:-0.47,95%CI:-1.35 to 0.41,I^(2)=88%,P=0.30)and calcium levels(MD:-0.33,95%CI:-0.95 to 0.29,I^(2)=94%,P=0.29).CONCLUSION Our study demonstrated that denosumab is significantly associated with mild and very severe hypocalcemia in patients with ESRD making it necessary to detect and prevent this side effect of treatmen

关键词： Denosumab End-stage renal disease Hypocalcemia Parathyroid hormone Dialysis

Drag Optimization of A Planing Vessel Based on the Stability Criteria Limits

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China Ocean Engineering 2019年第3期33卷 365-372页

作者： Yasin MASUMI amir H.NIKSERESHT Department of Mechanical and Aerospace Engineering Shiraz University of Technology

One of the important phases of designing a craft is stability analysis and optimization of the drag force in cruise speed. In this research the longitudinal and lateral stability of a planing hull craft (DTMB 62 model 4667-1) is investigated with some semi-empirical formulae and the effects of some important design parameters are investigated on the limit of stability region. Also on the basis of these empirical formulations and by using a genetic algorithm the drag force is optimized in each constant cruise speed with the stability criteria limits at a constant beam or projected area. Aspect ratio, the longitudinal position of the gravity center and deadrise angle are the optimization parameters. The results show that the aspect ratio and the longitudinal position of the gravity center are two important parameters in optimizing the drag force and for this planing vessel the drag force can be reduced by 22%.

关键词： longitudinal stability transverse stability drag-optimization Savitsky formula