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Investigation of sensitivity and threshold voltage shift of commercial mOSFETs in gamma irradiation

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Nuclear Science and Techniques 2016年第6期27卷 166-171页

作者： Saleh Ashrafi Baharak eslami Faculty of Physics University of Tabriz Department of Physics Payame Noor University

This article is about the absorbed-dose-dependent threshold voltage shift of the mOSFET *** of the mOSFETs has been tested in different gate *** of the transistors for 662 ke V gamma ray is studied in 1–5 Gy dose *** was found that for transistors irradiated in biased mode,significant changes in the threshold voltage occurred,and the sensitivity to gamma rays increased with the bias voltage.

关键词：阈值电压漂移 mOSFET γ射线照射敏感性商业吸收剂量偏置电压晶体管

A New Approach to Plane Failure of Rock Slope Stability Based on Water Flow Velocity in Discontinuities for the Latian Dam Reservoir Landslide

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Journal of mountain Science 2011年第2期8卷 124-130页

作者： morteza AHmADI majid eslami Department of mining Engineering Tarbiat Modares University Ghaem Consulting Engineers

The stability of slopes is always of great concern in the field of rock engineering. The geometry and orientation of pre-existing discontinuities show a larger impact on the behavior of slopes that is often used to describe the measurement of the steepness, incline, gradient, or grade of a straight line. One of the structurally controlled modes of failure in jointed rock slopes is plane failure. There are numerous analytical methods for the rock slope stability including limit equilibrium, stress analysis and stereographic methods. The limiting equilibrium methods for slopes under various conditions against plane failure have been previously proposed by several investigators. However, these methods do not involve water pressure on sliding surfaces assessments due to water velocity and have not yet been validated by case study results. This paper has tried to explore the effects of forces due to water pressure on discontinuity surfaces in plane failure through applying the improved equations. It has studied the effect of water flow velocity on sliding surfaces in safety factor, as well. New equations for considering water velocity (fluid dynamics) are presented. To check the validity of the suggested equations, safety factor for a case study has been determined. Results show that velocity of water flow had significant effect on the amount of safety factor. Also, the suggested equations have higher validity rate compared to the current equations.

关键词： Plane Failure Limit Equilibrium Safety Factor Water Velocity

Impact of reduced frequency on the time lag in pressure distribution over a supercritical airfoil in a pitch-pause-return motion

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Chinese Journal of Aeronautics 2019年第2期32卷 243-252页

作者： Haghighat Z.eslami Ali R.DAVARI m.R.SOLTANI Aerospace Division Department of Engineering Science and Research Branch Islamic Azad University Department of Aerospace Engineering Sharif University of Technology

Effects of reduced frequency, stop angle, and pause duration have been studied on a thin supercritical airfoil undergoing a pitch-pause-return motion, which is one of the classic maneuvers introduced by the AIAA Fluid Dynamics Technical Committee. Experiments were conducted in a low-speed wind tunnel at both a constant mean angle of attack and an oscillation amplitude with a reduced frequency ranging from 0.01 to 0.12. The desired stop angles of the airfoil were set to occur during the upstroke motion. The unsteady pressure distribution on the airfoil was measured for below, near, and beyond static stall conditions. Results showed that the reduced frequency and stop angle were the dominant contributors to the time lag in the flowfield. For stop angles in both belowand post-stall regions, the time for the flowfield to reach its steady state conditions, known as the time lag, decreased as the reduced frequency was increased. However, in the static-stall region and for a certain value of reduced frequency, a resonance phenomenon was observed, and a minimum time lag was achieved. The pressure distribution in this condition was shown to be highly influenced by this phenomenon.

关键词： Dynamic stall Pitch pause return motion Reduced frequency Static stall Time lag

Comparison of deep convolutional neural network classifiers and the effect of scale encoding for automated pavement assessment

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Journal of Traffic and Transportation Engineering(English Edition) 2023年第2期10卷 258-275页

作者： Elham.eslami Hae-Bum Yun Department of Civil Environmental and Construction EngineeringUniversity of Central FloridaOrlandoFL 32816USA

Deep learning has received a growing interest in recent years for detecting different types of pavement distresses and automating pavement condition assessment.A proper choice of deep learning models is key for successful pavement assessment *** this study,we first present a comprehensive experimental comparison of state-of-the-art image classification models to evaluate their performances on 11 pavement objects *** experiments are conducted in different dimensions of comparison,including deep classifier architecture,effects of network depth,and computational *** convolutional neural network(CNN)classifiers widely used in transportation applications,including VGG16,VGG19,ResNet50,DenseNet121,and a generic CNN(as the control model),are tested with a comprehensive pixel-level annotated dataset for 11 different distress and non-distress classes(UCF-PAVE 2017).In addition,we investigate a simple yet effective approach of encoding contextual information with multi-scale input tiles to classify highly random pavement objects in size,shape,intensity,texture,and *** comparison results show that the multi-scale approach significantly improves the classification accuracy for all compared deep classifiers at a negligible extra computational ***,we provide recommendations of how to improve the classification performance of deep CNNs for automated pavement condition assessment based on the comparison results.

关键词： Road damage detection Automated pavement condition assessment Convolutional neural networks Deep learning multi-class classification

Design adaptations in a large and deep urban excavation: Case study

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Journal of Rock mechanics and Geotechnical Engineering 2019年第2期11卷 389-399页

作者： Amir Alipour Abolfazl eslami Department of Civil and Environmental Engineering Amirkabir University of Technology

In this paper, design, re-design, and performance of a long-standing very deep excavation, which was originally planned to depth of 38 m, are presented. Over-digging was not planned in the original design,thus the reassessment was performed. Two main topics were followed: deepening to increase the maximum depth of an existent excavation from 38 m to 42.5 m, and feasibility for upgrading a predesigned support system from temporary to permanent support system. The geological investigations in the project site illustrated a type of stiff and cemented coarse-grained alluvium. An observational approach with additional geotechnical investigations and in situ tests was applied. Back analyses of stability of an unsupported access ramp, as well as deformation monitoring of walls, were used in order to review geotechnical design parameters that represent the full-scale behavior of the ground. Additional nails and soldier piles together with building mat foundation were implemented as a complementary lateral support in the retaining system. From an engineering point of view, by assuming a corrosion rate of 0.065 mm/a for existent rebars, according to chemical and electrical resistivity tests, the long-term performance of the revised retaining system was verified by static and pseudo-dynamic ultimate limit state analyses. Performance monitoring during the construction shows that the measured deformation is in the lower limit of the prediction.

关键词： Deep excavation Field observations In situ tests Support system Adaptive design Inverse analysis

Simultaneous Employment of Generation Rescheduling and Incentive-based Demand Response Programs for Congestion management in Case of Contingency

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Journal of modern Power Systems and Clean Energy 2022年第4期10卷 902-912页

作者： Seyed Erfan Hosseini Alimorad Khajehzadeh mahdiyeh eslami Department of Electrical Engineering Kerman branchIslamic Azad UniversityKermanIran

Relieving congestion significantly influences the operation and security of the transmission ***,the congestion alleviation of transmission network in all power systems is ***,it could prevent price spikes and/or involuntary load shedding and impose high expenses on the transimission network,especially in case of ***,the increasing or decreasing generation rescheduling has been used as one of the most imperative approaches for correctional congestion management when a contingency ***,demand response programs(DRPs)could also be a vital tool for managing the ***,the simultaneous employment of generation rescheduling and DRPs is proposed for congestion management in case of *** objective is to reschedule the generation of power plants and to employ DRPs in such a way so as to lessen the cost of *** crow search algorithm is employed to determine the *** accuracy and efficiency of the proposed approach are assessed through the tests conducted on IEEE 30-bus and 57-bus test *** results of various case studies indicate the better performance of the proposed approach in comparison with different approaches presented in the literature.

关键词： Congestion management demand response generation rescheduling transmission economy transmission lines

Evaluation and modification of inclusion characteristics in HK40 heatresistant cast steel

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International Journal of minerals,metallurgy and materials 2013年第4期20卷 354-359页

作者： Ali Navaei Reza eslami-Farsani majid Abbasi Faculty of mechanical Engineering K.N. Toosi University of Technology Department of materials Engineering Babol Noshirvani University of Technology

Specifications of inclusions such as the type, morphology, number, composition, size, and place of inclusions in HK40 heat-resistant casting steel were studied by optical microscopy and scanning electron microscopy equipped with an energy-dispersive spectroscopy system. The effects of calcium silicide （CaSi） addition on these characteristics were evaluated at two pouring temperatures of 1420℃ and 1470℃. It was found that most of the appeared inclusions were in the type of chromium oxide. CaSi addition had a significant effect on the morphological modification, size and distribution of inclusions as well as changing the composition to oxide-sulfide compounds.

关键词： heat-resistant steel inclusions calcium silicide modification

Opposition-Based Firefly Algorithm for Earth Slope Stability Evaluation

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China Ocean Engineering 2014年第5期28卷 713-724页

作者： mohammad KHAJEHZADEH mohd Raihan TAHA mahdiyeh eslami Civil Engineering Department Anar Branch Islamic Azad UniversityAnar Iran Civil and Structural Engineering Department National University of MalaysiaBangi Selangor Malaysia Department of Electrical Engineering Kerman Branch Islamic Azad UniversityKerman Iran

This paper introduces a new approach of firefly algorithm based on opposition-based learning （OBFA） to enhance the global search ability of the original algorithm. The new algorithm employs opposition based learning concept to generate initial population and also updating agents’ positions. The proposed OBFA is applied for minimization of the factor of safety and search for critical failure surface in slope stability analysis. The numerical experiments demonstrate the effectiveness and robustness of the new algorithm.

关键词： firefly algorithm opposition based learning safety factor slope stability

Synthesis and spectral properties of Nd-doped glass-ceramics in SiO_2-CaO-mgO system prepared by sol-gel method

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Journal of Rare Earths 2013年第6期31卷 595-599页

作者： masoud eslami Zohreh Hamnabard Ali Nemati materials Science & Engineering Department Sharif University of Technology materials Research School Ceramic Group

SiO2-CaO-mgO glass and glass-ceramic powder doped with Nd3＋ were synthesized with sol-gel method. Tetraethylorthosilicate （TEOS）, Ca（NO3）2？4H2O, mg（NO3）2？6H2O, Nd（NO3）3？6H2O, ethanol, distilled water, and HNO3 were used as starting materials. The synthesized powder’s properties were examined with simultaneous thermal analysis （STA）, X-ray diffraction （XRD）, photoluminescence （PL） and scanning electron microscopy （SEm） analysis. The STA curves showed that the softening point and crystallization temperatures were shifted to higher temperatures with increasing dopant content. Regarding XRD patterns of glass samples, Nd was found to act as an intermediate oxide in glass matrix. The XRD patterns of glass-ceramic samples indicated that bredigite and akermanite crystallized in the glass matrix after heat treating at 900 oC. The fluorescence spectra showed that glass-ceramics emitted much stronger irradiation than glasses with the same dopant content. The SEm images illustrated uniform and homogeneous distribution of applied oxides in glass and glass-ceramic compositions.

关键词： glass glass-ceramic synthesis sol-gel method spectral properties rare earths