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Non-isolated Step-up DC-DC Converter Based on Switched Capacitor Cells

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CSEE Journal of Power and Energy Systems 2023年第3期9卷 1161-1172页

作者： Farid Mohammadi Gevork B.Gharehpetian Hasan Rastegar Mohammad Farhadi-Kangarlu amirkabir university of technology TehranIran Faculty of Electrical and Computer Engineering Urmia UniversityUrmiaIran

A non-isolated high gain step-up DC-DC converter for low power applications is suggested in this *** the designed transformerless converter,the main switch current and voltage stress is reduced while maintaining high voltage *** instance,with a duty cycle of 0.5 a voltage gain equal to 5 is achieved while the normalized switch voltage stress is ***,it decreases power losses of active and passive *** the proposed converter design,the switched-capacitor(SC)technique is used to obtain maximum voltage transfer gain using only one *** three modes of operation,i.e.,continuous conduction mode(CCM),boundary conduction mode(BCM),and discontinuous conduction mode(DCM),are studied in *** small signal analysis(SSA)of the designed converter is investigated,and its steady-state model is examined under *** of the proposed converter proposed in this study is assessed and tested using a *** of the converter is recorded above 94%in a wide range of output ***,compared to the other converters,the results suggest satisfactory performance of the designed *** issue of the proposed converter is that its input current is not smooth due to using the switched-capacitor cell in its *** issue is alleviated by using input filters.

关键词： DC-DC converter high voltage gain nonisolated switched capacitor cell voltage stress

An approach for wellbore failure analysis using rock cavings and image processing

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Journal of Rock Mechanics and Geotechnical Engineering 2018年第5期10卷 865-878页

作者： Christopher Skea Alireza Rezagholilou Pouria Behnoud Far Raoof Gholami Mohammad Sarmadivleh Department of Petroleum Engineering Curtin University Department of Petroleum Engineering Amirkabir University of Technology

There have been interests to link different cuttings/cavings to various wellbore failure types during drilling. This concept is essential when caliper and image logs are not available. Identification ofwellbore failure during drilling gives more chance of immediate actions before wireline logging program. In this paper, an approach was presented based on the image processing of ditch cuttings. This approach uses the sphericity and roundness of cuttings as input data to classify caving types and subsequently deter- mine the dominant failure type. Likewise, common definitions of cavings were discussed initially before a new criterion is suggested. This quantitative criterion was examined by observations from caliper and acoustic image logs as well. The proposed approach and criterion were implemented on ditch cuttings taken from a well in Western Australia. Results indicate that the primary failure is shear failure （breakout） due to high levels of angular cavings. However, another failure due to the fluid invasion into pre-existing fractures was also recorded by blocky cavings.

关键词： Caving shape Cuttings Drilling Image analysis Wellbore failures Roundness Sphericity

One-loop approximation of Mφller scattering in generalized Krein-space quantization

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Science China(Physics,Mechanics & Astronomy) 2009年第2期52卷 212-217页

作者： F. PAYANDEH M. MEHRAFARIN M. V. TAKOOK Physics Department Amirkabir University of Technology Payame Noor university Physics Department Razi University

It has been shown that the negative-norm states necessarily appear in a covariant quantization of the free minimally coupled scalar field in de Sitter spacetime. In this processes ultraviolet and infrared di- vergences have been automatically eliminated. A natural renormalization of the one-loop interacting quantum field in Minkowski spacetime (λφ 4) has been achieved through the consideration of the nega- tive-norm states defined in Krein space. It has been shown that the combination of quantum field theory in Krein space together with consideration of quantum metric fluctuation, results in quantum field the- ory without any divergences. Pursuing this approach, we express Wick’s theorem and calculate Mφller scattering in the one-loop approximation in generalized Krein space. The mathematical consequence of this method is the disappearance of the ultraviolet divergence in the one-loop approximation.

关键词： quantum field theory Krein space negative energy states

New Penta-ether as the Internal Donor in the MgCl2-supported ZieglerNatta Catalysts for Propylene Polymerization

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Chinese Journal of Polymer Science 2016年第3期34卷 268-279页

作者： Roya Zahedi Faramarz Afshar Taromi Seyed Heidar Mirjahanmardi Mehdi Nekoomanesh Haghighi Khosrow Jadidi Roghayeh Jamjah Department of Chemistry Amirkabir University of Technology15875-4413TehranIran Department of Polymer Engineering Amirkabir University of Technology15875-4413TehranIran Department of Polymer Engineering A mirkab ir University of Technology-Mahs hahr Campus63516-43659MahshahrIran Iran Polymer and Petrochemical Institute(IPPI) 14977-13115TehranIran Department of Chemistry Shahid Beheshti University19839-69411TehranIran

The penta-ether compound was synthesized by the reaction of di（trimethylolpropane） with sodium hydride as the strong base and methyl iodide as the alkyl halide. This compound was characterized by NMR, FTIR, and GC techniques. The MgCl_2-supported titanium catalysts were incorporated with varying amounts of penta-ether compound as the internal donor and also the catalysts without the internal donor were synthesized. The synthesized catalysts and the conventional ZieglerNatta catalyst were characterized. The titanium contents were determined by spectrophotometry, magnesium by complexometric titration and chloride by argentometric titration. The effects of the new internal donor on propylene polymerization with the prepared MgCl_2-supported Ziegler-Natta catalysts were investigated and then these results were compared to the results obtained using the conventional diisobutyl phthalate-besed-Ziegler-Natta catalyst. The highest crystallinity degree, melting temperature, and isotacticity of polypropylene were obtained using the catalyst with a pentaether/Mg molar ratio equal to 0.21.

关键词： Williamson reaction Internal donor Ziegler-Natta catalyst External donor Propylene polymerization

Intuitionistic Menger inner product spaces and applications to integral equations

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Applied Mathematics and Mechanics(English Edition) 2010年第4期31卷 415-424页

作者：张石生 M.GOUDARZI R.SAADATI S.M.VAEZPOUR Department of Mathematics Yibin University Department of Mathematics and Computer Science Amirkabir University of Technology

In this paper, first introduce and define an intuitionistic Menger inner product space, and then, obtain a new fixed point theorem in a complete intuitionistic Menger inner product space. As an application, the result... 详细信息

关键词： intuitionistic Menger inner product space Volterra integral equation,h-type t-norm fixed point theorem

Strategic Bidding in Distribution Network Electricity Market Focusing on Competition Modeling and Uncertainties

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Journal of Modern Power Systems and Clean Energy 2021年第3期9卷 561-572页

作者： Mehrdad Mallaki Mehdi S.Naderi Mehrdad Abedi Saeed D.Manshadi Gevork B.Gharehpetian the Electrical Engineering Department Amirkabir University of TechnologyTehranIran Iran Grid Secure Operation Research Centre Amirkabir University of TechnologyTehranIran theDepartment of Electrical and Computer Engineering San Diego State UniversitySan DiegoUSA

Developing the electricity market at the distribution level can facilitate the energy transactions in distribution networks with a high penetration level of distributed energy resources(DERs)and microgrids(MGs).However,the lack of comprehensive information about the marginal production cost of competitors leads to uncertainties in the optimal bidding strategy of *** electricity demand within the network and the price in the wholesale electricity market are two other sources of the *** this paper,a day-ahead-market-based framework for managing the energy transactions among MGs and other participants in distribution networks is introduced.A game-theory-based method is presented to model the competition and determine the optimal bidding strategy of participants in the *** optimization technique is employed to capture the uncertainties in the marginal cost of ***,the uncertainties in demand are modeled using a scenario-based stochastic *** results ob-tained from case studies reveal the merit of considering competition modeling and uncertainties.

关键词： Competition modeling bidding strategy distribution network electricity market microgrid uncertainty robust optimization

Determination and stability analysis of ultimate open-pit slope under geomechanical uncertainty

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International Journal of Mining Science and technology 2014年第1期24卷 105-110页

作者： Ali Moradi Afrapoli Morteza Osanloo Department of Mining Metallurgy and Petroleum EngineeringAmirkabir University of Technology

In open-pit mines,pit slope as one of the important parameters affects the mine economy and total minable reserve,and it is also affected by different uncertainties which arising from many *** of the most critical sources of uncertainty effects on the pit slope design is rock mass geomechanical *** comparing the probability of failure resulted from deterministic procedure and probabilistic one,this paper investigated the effects of aforesaid uncertainties on open-pit slope stability in metal *** this way,to reduce the effect of variance,it implemented Latin Hypercube Sampling(LHS)***,a hypothesis test was exerted to compare the effects on two cases in Middle ***,the investigation approved high influence of geomechanical uncertainties on overall pit steepness and stability in both iron and copper mines,though on the first case the effects were just over.

关键词： Safety factor Probability of failure Geomechanical property uncertainty Overall pit slope Stability analysis

Reply to Discussion on “Empirical methods for determining shaft bearing capacity of semi-deep foundations socketed in rocks”

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Journal of Rock Mechanics and Geotechnical Engineering 2018年第3期10卷 607-609页

作者： S.Rezazadeh A.Eslami Department of Civil and Environmental Engineering Amirkabir University of Technology

Semi-deep foundations socketed in rocks are considered to be a viable option for the foundations in the presence of heavy loads imposed by high-rise buildings and special structures, due to the low settlement and high bearing capacity. In this study, the unconfined compressive strength（UCS） and rock mass cuttability index（RMCI） have been applied to investigating the shaft bearing capacity. For this purpose, a comprehensive database of 178 full-scale load tests is compiled by adding a data set（n = 72）collected by Arioglu et al.（2007） to the data set（n = 106） presented in Rezazadeh and Eslami（2017）.Using the database, the applicability and accuracy of the existing empirical methods are evaluated and new relations are derived between the shaft bearing capacity and UCS/RMCI. Moreover, a general equation in case of unknown rock types is proposed and it is verified by another set of data（series 3 in Rezazadeh and Eslami（2017））. Since rock-socketed shafts are supported by rock mass（not intact rock）,a reduction factor for the compressive strength is suggested and verified in which the effect of discontinuities is considered using the modified UCS, based upon RMR and RQD to consider the effect of the rock mass properties.

关键词： Shaft bearing capacity Semi-deep foundations Database Unconfined compressive strength (UCS) Rock mass cuttability index (RMCI)

An adaptive sliding mode controller design to cope with unmatched uncertainties and disturbance in a MEMS voltage reference source

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Control Theory and technology 2021年第2期19卷 211-226页

作者： Ehsan Ranjbar Mostafa Yaghoubi Amir Abolfazl Suratgar MEMS Dynamics&Control Research Group Industrial Control LabDepartment of Electrical EngineeringAmirkabir University of TechnologyTehranIran Department of Electrical Engineering Amirkabir University of TechnologyTehranIran

Tunable micro-electro-mechanical systems(MEMS)capacitors as the fundamental parts are embedded in MEMS AC voltage reference sources(VRS).Being concerned with the accuracy of the output voltage in the reference sources,it gets important to address uncertainties in the physical parameters of the MEMS *** uncertainties have the great inevitable potentiality of bringing about output voltage *** output deterioration is more remarkable when the uncertainties are accompanied by disturbance and *** have been making great attempts to make the MEMS adjustable capacitor with desired rigorous physical *** have also tried to mitigate physical parameter ***,ambiguity in the values of the parameters inescapably occurs in fabrication procedures since the micro-machining process might itself suffer from *** a proportional integral(PI)adaptive sliding mode controller(ASMC),both terms of matched and unmatched uncertainties as well as the disturbance,are addressed in this work for the MEMS AC VRS so that a strict voltage is stabilized while the system is simultaneously subjected into uncertainties and exogenous ***-talk,some inertial forces,and electrostatic coercions may appear as matched and unmatched *** in stiffness and damping coefficients might also take place as matched uncertainties due to variations in the fabrication process or even working *** simulation results in the paper are persuasive and the controller design has shown a satisfactory tracking performance.

关键词： Matched and unmatched disturbance Uncertainty MEMS Adaptive sliding mode controller Proportional and integral sliding surface Capacitive plates