检索结果-南通市图书馆

Microstructure,mechanical properties and corrosion resistance of as-cast and as-extruded Mg-4Zn-1La magnesium alloy

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2020年第8期39卷 909-917页

作者： Huseyin Zengin yunus turen Hayrettin Ahlatci Yavuz Sun Department of Metallurgy and Materials Engineering Karabuk University78050 KarabukTurkey Iron and Steel Institute Karabuk University78050 KarabukTurkey

Microstructure,mechanical properties and corrosion resistance of as-cast and as-extruded Mg-4 wt%Zn-1 wt%La magnesium alloys were *** alloys were produced by low-pressure die casting method and extruded at 350℃after homogenization at 400℃for 24 *** results show that the as-cast alloy mainly consists of primaryα-Mg matrix and Mg-Zn-La ternary second phases(also called T-Phase)along grain boundaries and isolated spherical particles inside the *** extrusion at350℃,the average grain size decreases by 81%due to dynamic recrystallization mechanism and T-phase particles are distributed along the extrusion *** elongation,yield strength and tensile strength of the as-cast Mg-4Zn-1La alloy increase by 179%,90%and 40%,respectively,as a result of the extrusion *** as-extruded Mg-4Zn-1La alloy shows better corrosion resistance than the as-cast alloy due to increased grain boundaries and decreased content of T-phase.

关键词： Magnesium alloys La modification Extrusion Microstructure Mechanical properties Corrosion

Evolution of Microstructure, Residual Stress, and Tensile Properties of Mg–Zn–Y–La–Zr Magnesium Alloy Processed by Extrusion

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2019年第11期32卷 1309-1319页

作者： Huseyin Zengin yunus turen Muhammet Emre Turan Fatih Ayd?n Department of Metallurgical and Materials Engineering Karabuk University Baliklarkayasi Mevkii Demir Celik Kampusu

The microstructure, texture, residual stress, and tensile properties of Mg–6 Zn–2 Y–1 La–0.5 Zr(wt%) magnesium alloy were investigated before and after extrusion process, which performed at 300 °C and 400 °C. The microstructural characterizations indicated that the as-cast alloy was comprised of α-Mg, Mg–Zn, Mg–Zn–La, and Mg–Zn–Y phases. During homogenization at 400 °C for 24 h, most of the secondary phases exhibited partial dissolution. Extrusion process led to a remarkable grain refi nement due to dynamic recrystallization(DRX). The degree of DRX and the DRXed grain size increased with increasing extrusion temperature. The homogenized alloy did not show a preferential crystallographic orientation, whereas the extruded alloys showed strong basal texture. The extrusion process led to a signifi cant improvement on the compressive residual stress and mechanical properties. The alloy extruded at 300 °C exhibited the highest basal texture intensity, the compressive residual stress and hardness, and yield and tensile strengths among the studied alloys.

关键词： ZK60 Magnesium alloy Residual stress Texture Mechanical properties Extrusion

Influence of Sn addition on microstructure and corrosion resistance of AS21 magnesium alloy

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2019年第7期29卷 1413-1423页

作者： Huseyin ZENGIN yunus turen Hayrettin AHLATCI Yavuz SUN Abdullah Cahit KARAOGLANLI Department of Metallurgical and Materials Engineering Karabuk University Turkey Department of Metallurgical and Materials Engineering Bartιn University Turkey

This study aims to investigate the influence of Sn addition on microstructure and corrosion properties of AS21 magnesium alloys. The AS21 alloys with 0, 0.5, 1 and 2 wt.% Sn additions were produced by low pressure die casting method. Microstructure characterizations were performed by optical and scanning electron microscopy. Corrosion properties of the alloys were examined by immersion and electrochemical corrosion tests in 3.5% NaCl solution. The microscopic results showed that AS21 alloy consisted of α-Mg, isolated β-Mg17Al12 and Chinese script type Mg2Si intermetallic phases. With increasing amount of Sn, the distribution of Mg2Si phase became more discrete and denser. After 2 wt.% Sn addition, a Sn-rich network structure formed throughout the microstructure and islands of Chinese script shape were made of shorter rods of Mg2Si phase. The constant immersion corrosion tests revealed that increasing Sn addition led to a continual decrease in the degradation of AS21 alloys, in which the corrosion rate of AS21 alloy was decreased by approximately 65% with 2 wt.% Sn addition. The electrochemical corrosion tests also showed that the corrosion resistance of AS21 alloy was gradually improved with increasing Sn content.

关键词： AS21 magnesium alloy Sn addition microstructure corrosion

Grobner-Shirshov Basis of Twisted Generic Composition Algebras of Affine Type

在线全文

学校读者我要写书评

暂无评论

Algebra Colloquium 2017年第1期24卷 109-122页

作者： Gulshadam yunus Abdukadir Obul College of Mathematics and System Sciences Xinjiang University Urumqi 830046 China

In this paper, by using PBW bases for the twisted generic composition algebras of affine type, we prove that the set of the skew-commutator relations of the iso-classes of indecomposable representations forms a minima... 详细信息

关键词： Ringel-Hall algebra indecomposable modules Grobner-Shirshov basis skew-commutator relations

Grbner-Shirshov Basis of Quantum Group of Type D_4

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Annals of Mathematics,Series B 2011年第4期32卷 581-592页

作者： Gulshadam yunus Abdukadir OBUL College of Mathematics and System Sciences Xinjiang University

The authors take all isomorphism classes of indecomposable representations as new generators, and obtain all skew-commutators between these generators by using the Ringel-Hall algebra method. Then they prove that the ... 详细信息

关键词： Ringel-Hall algebra Indecomposable modules GrSbner-Shirshov basis Compositions

Effect of surfactant on the dielectric and electrorheological properties of zinc borate/silicone oil dispersions

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2019年第12期26卷 1523-1530页

作者： Omer yunus Gumus Halil Ibrahim Unal Bursa Technical University Engineering and Natural Sciences FacultyFiber and Polymer Engineering DepartmentBursa 16310Turkey Gazi University Science FacultyChemistry DepartmentSmart Materials Research Lab.Ankara 06500Turkey

Zinc borate(ZB)particles dispersed in silicone oil(SO)at concentrations of φ=5vol%-20vol% were subjected to dielectric analysis to elucidate their polarization strength,time,and *** revealed that all virgin dispersions lacked *** X-100,a non-ionic surfactant,was added to ZB/SO dispersions to enhance the polarizability of ZB *** addition of 1vol% Triton X-100 enhanced the polarizability of ZB/SO dispersions,and the 15vol% ZB/SO system provided the highest dielectric difference Δε′(the difference in ε′values at zero and infinite frequency,Δε′=ε0–ε∝)of *** electrorheological(ER)activities of the ZB/SO/Triton-X dispersion system were determined through the ER response test,and viscoelastic behaviors were investigated via oscillation tests.A recoverable deformation of 36% under an applied electrical field strength of 1.5 kV/mm was detected through creep and creep recovery tests.

关键词： zinc borate electrorheological fluids dielectric analysis surfactant

Modeling, Analysis and Simulation of a High-Efficiency Battery Control System

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2023年第7期136卷 709-732页

作者： Mohammed Ayad Alkhafaji yunus Uzun College of Engineering Technology National University of Science and TechnologyDhi QarIraq Aksaray University Faculty of EngineeringDepartment of Electrical and Electronics EngineeringAksarayTurkey

This paper explains step-by-step modeling and simulation of the full circuits of a battery control system and connected together starting from the AC input source to the battery control and storage *** three-phase half-controlled rectifier has been designed to control and convert the AC power into DC *** addition,two types of direct current converters have been used in this paper which are a buck and bidirectional DC/DC *** systems adjust the output voltage to be lower or higher than the input *** the buck converters,the main switch operates in conduction or cut-off mode and is triggered by a Pulse-Width Modulated(PWM)*** output and input voltage levels ratio are used to calculate thePWMsignal’s duty ***,the duty cycle indicates the operation mode of the converter in steady-state *** this study,we analyze and control of a buck converter with the PWM ***,the bidirectional DC/DC converter has been achieved and optimized by PI control methods to control the battery charging and discharging *** simulation has been applied via the Matlab/Simulink *** results show the activity of each part of the designed circuits starting from the converters and the battery control system in charge and discharge modes.

关键词： Rectifier buck converter bidirectional DC/DC converter PI controller Pulse-WidthModulation(PWM) battery controller

Hybrid NOMA Based MIMO Offloading for Mobile Edge Computing in 6G Networks

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China Communications 2022年第10期19卷 12-20页

作者： yunus Dursun Fang Fang Zhiguo Ding School of Electrical and Electronic Engineering University of ManchesterManchesterUK Department of Electrical and Computer Engineering and the Department of Computer Science Western UniversityLondonCanada

Non-orthogonal multiple access (NOMA), multiple-input multiple-output (MIMO) and mobile edge computing (MEC) are prominent technologies to meet high data rate demand in the sixth generation (6G) communication networks. In this paper, we aim to minimize the transmission delay in the MIMO-MEC in order to improve the spectral efficiency, energy efficiency, and data rate of MEC offloading. Dinkelbach transform and generalized singular value decomposition (GSVD) method are used to solve the delay minimization problem. Analytical results are provided to evaluate the performance of the proposed Hybrid-NOMA-MIMO-MEC system. Simulation results reveal that the H-NOMA-MIMO-MEC system can achieve better delay performance and lower energy consumption compared to OMA.

关键词： NOMA MEC MIMO Generalized sin-gular value decomposition sixth generation networks(6G) delay minimization

Multi-output optimization of tribological characteristics control factors of thermally sprayed industrial ceramic coatings using hybrid Taguchi-grey relation analysis

在线全文

学校读者我要写书评

暂无评论

Friction 2016年第3期4卷 208-216页

作者： Mohammed yunus Mohammad S.ALSOUFI Mechanical Engineering Department College of Engineering and Islamic Architecture Umm Al-Qura University Makkah 21514 Kingdom of Saudi Arabia

Lasma-sprayed thermal barrier coatings (TBCs) are gaining wide popularity and becoming more attractive for many industrial applications due to their high strength, thermal barrier/fatigue characteristics at elevated temperatures, resistance to chemical degradation, wear resistance, and environmental corrosion protection provided when coated on the surface of engineering components. To characterize the tribological properties of TBCs, a better understanding of their failure mechanisms and a thorough investigation of their performance are required. In this research, we used Taguchi-based grey relational analysis (GRA) to optimize the process parameters of various tribological characteristics of ceramic coatings applied via an atmospheric plasma spray process. Using Taguchi L16 factorial mixed-level experimental design, we also evaluated tribological characteristics such as wear loss and the coefficient of friction. Using GRA, we successfully performed a multiple output optimization and ranking of the control factors. Based on ANOVA results, we evaluated the significance of each process parameter and validated our findings in tests using the obtained optimum set of process parameters. Our study results will help to minimize wear loss and the coefficient of friction and to maximize TBC life.

关键词： tribological characteristics wear loss coefficient of friction hybrid Taguchi-grey relational analysis analysis of variance (ANOVA) thermal barrier coatings (TBCs)