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Electrical annealing of severely deformed copper: microstructure and hardness

International Journal of Minerals,Metallurgy and Materials 2017年第10期24卷 1158-1168页

作者： Saeed Nobakht mohsen kazeminezhad Department of Materials Science and Engineering Sharif University of Technology Azadi Avenue Tehran Iran

Commercial pure copper sheets were severely deformed after primary annealing to a strain magnitude of 2.32 through constrained groove pressing. After induction of an electrical current, the sheets were heated for 0.5, 1, 2, or 3 s up to maximum temperatures of 150, 200, 250, or 300℃. To compare the annealing process in the current-carrying system with that in the current-free system, four other samples were heated to 300℃ at holding times of 60, 90, 120, or 150 s in a salt bath. The microstructural evolution and hardness values of the samples were then investigated. The results generally indicated that induction of an electrical current could accelerate the recrystallization process by decreasing the thermodynamic barriers for nucleation. In other words, the current effect, in addition to the thermal effect, enhanced the diffusion rate and dislocation climb velocity. During the primary stages of recrystallization, the grown nuclei of electrically annealed samples showed greater numbers and a more homogeneous distribution than those of the samples annealed in the salt bath. In the fully recrystallized condition, the grain size of electrically annealed samples was smaller than that of conventionally annealed samples. The hardness values and metallographic images obtained indicate that, unlike the conventional annealing process, which promotes restoration phenomena with increasing heating time, the electrical annealing process does not necessarily promote these phenomena. This difference is hypothesized to stem from conflicts between thermal and athermal effects during recrystallization.

关键词： annealing severe plastic deformation copper microstructure hardness

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Effects of non-isothermal annealing on microstructure and mechanical properties of severely deformed 2024 aluminum alloy

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Transactions of Nonferrous Metals Society of China 2017年第1期27卷 1-9页

作者： Saeed KHANI MOGHANAKI mohsen kazeminezhad Department of Materials Science and Engineering Sharif University of TechnologyAzadi Avenue 11155-9466TehranIran

Microstructure and mechanical properties of AA2024 after severe plastic deformation （SPD） and non-isothermal annealing were investigated. The non-isothermal treatment was carried out on the severely deformed AA2024, and the interaction between restoration and precipitation phenomena was investigated. Differential scanning calorimetry, hardness and shear punch tests illustrate that static recovery and dissolution of GPB zones/Cu-Mg co-clusters occur concurrently through non-isothermal annealing. Scanning electron microscope and electron backscatter diffraction illustrate that non-isothermal annealing of deformed AA2024 up to 250 ℃ promotes the particle-free regions and also particle stimulated nucleation. Results show that through heating with the rate of 10 ℃/min up to 250 ℃, the ultimate shear strength and the hardness are maximum due to the presence of S＇/S phases which have been detected during non-isothermal differential scanning calorimetry experiment. Also, recrystallization phenomenon occurs in temperature range which includes the dissolution of S＇/S phases. The concurrent recrystallization and dissolution of S＇/S phase at 380 ℃ have been verified by differential scanning calorimetry, mechanical properties, and optical microscope.

关键词： AA2024 alloy severe plastic deformation non-isothermal annealing microstructure mechanical properties

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Correlation between structural phase transition and physical properties of Co^(2+)/Gd^(3+)co-substituted copper ferrite

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Journal of Rare Earths 2024年第7期42卷 1344-1353,I0006页

作者： mohsen Choupani Ahmad Gholizadeh School of Physics Damghan UniversityDamghan36716-45667Iran

The doping of the spinel ferrites with selective cations usually improves the properties of the parent *** effect of Co^(2+)/Gd^(3+)co-substitution on the microstructure,optical,and magnetic properties of Cu1-xCoxFe2-xGdxO4 prepared by the citrate-nitrate auto-combustion synthesis was *** of the samples was performed with powder X-ray diffraction(XRD),Raman and Fouriertransform infrared(FTIR)spectroscopy,field-emission scanning electron microscopy,X-ray energydispersive spectroscopy,UV-Vis spectroscopy,and a vibrating sample *** results of XRD,Raman,and FTIR analysis show a gradual structural phase transition from a tetragonal(I41/amd)structure to a cubic(Fd3m)*** bandgap energy of the studied samples is in a range of 1.57-1.75 eV with a minimum in sample x=0.06 and then *** investigations show that the presence of Co^(2+)/Gd^(3+)cations in an octahedral site of the copper ferrite structure could increase saturation magnetization and coercive field from 567.9 Oe and 23.62 emu/g to 929.4 Oe and 28.27 emu/g,respectively.

关键词： Spinel copper ferrite Citrate-nitrate method Structure phase transition Microstructure properties Magnetic properties Rare earths

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奥氏体→铁素体转变的模拟

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钢铁译文集 2013年第1期 52-55页

作者： mohsen kazeminezhad 韦菁(译) 詹华(校对)

本文介绍了一种基于Q态Potts模型的算法，用以模拟奥氏体→铁素体转变。该算法可以准确地跟踪相变过程中所形成相的界面迁移。算法内考虑到了相变期间的化学自由能、应变自由能以及奥氏体-奥氏体、铁素体-铁素体和奥氏体-铁素体界面能... 详细信息

本文介绍了一种基于Q态Potts模型的算法，用以模拟奥氏体→铁素体转变。该算法可以准确地跟踪相变过程中所形成相的界面迁移。算法内考虑到了相变期间的化学自由能、应变自由能以及奥氏体-奥氏体、铁素体-铁素体和奥氏体-铁素体界面能变化的影响。从算法中可以计算出各冷却速率下的相变动力学和铁素体平均晶粒尺寸。计算结果与实验结果极为吻合。

关键词：模型相变钢奥氏体铁素体动力学

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The interaction of history and modern thought in the creation of Iran’s architecture by investigating the approaches of past-oriented architecture

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Frontiers of Architectural Research 2024年第3期13卷 459-486页

作者： mohsen Kamali Department of Architecture Faculty of Arts and ArchitectureYazd UniversityYazdIran

The relationship between tradition and modernity significantly influences society,culture,and architectural *** philosophy offers a framework for exploring the impact of traditional architecture on contemporary Iranian architecture from different perspectives and *** viewpoints exist on whether historical architecture can be a defining characteristic of contemporary architectural *** an in-depth review of analysis-centred architectural literature,a unique method was chosen for analysing contemporary architecture and gaining insight into its *** main goal of this study is to establish a productive relationship between past-oriented architecture,innovative architectural concepts,and contemporary *** article examines three critical viewpoints,tradition as imitation,transmission,and transformation,alongside analysing their influential components on architectural form to gain insight into productively connecting with historical achievements and show that the role of history is to add new values to architecture-conscious needs that have changed during ***,the challenge lies in finding a suitable path among diverse perspectives and reinterpretations and establishing a productive relationship with history and contemporary thought.

关键词： Tradition Modernism Past-oriented architecture Contemporary Iranian architecture Concept-oriented architecture Contemporary architectural approaches

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On the occurrence of Neoplanorbulinella Matsumaru, 1976(Foraminifera) from the late Oligocene of Central Iran(Qom Formation):Palaeobiogeographic implications

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Journal of Palaeogeography 2024年第1期13卷 80-91页

作者： Mehdi Sarfi mohsen Yazdi-Moghadam School of Earth Sciences Damghan UniversityDamghan ***Iran National Iranian Oil Company Exploration Directorate Sheikh Bahaie SquareTehran ***Iran

The shallow marine carbonates of the upper Oligocene Qom Formation yielded several occurrences of the foraminiferan genus Neoplanorbulinella Matsumaru. Neoplanorbulinella saipanensis Matsumaru has so far been recorded from the late Eocene-early Miocene of Japan and late Oligocene of NE Italy whereas N. malatyaensis Gedik is only reported from the Oligocene from its type locality in the Malatya Basin, eastern Turkey. The new records reported here from the Qom Formation indicate that both species occur in the Dobaradar section, ca. 10 km south of the city of Qom in North-Central Iran. The palaeogeographic distribution of these two species therefore has to be extended as far as the palaeolongitude of current Central *** accompanying larger benthic foraminifers, including Miogypsinoides complanatus(Schlumberger),M. formosensis Yabe and Hanzawa, Spiroclypeus margaritatus(Schlumberger), Operculina complanata(Defrance), and Risananeiza pustulosa Boukhary et al., indicate the upper Chattian SBZ 23 Zone. The coexistence of the N. saipanensis and N. malatyaensis points to suitable palaeobiogeographic conditions of Central Iran to host Western and Eastern Tethyan taxa.

关键词： Larger foraminifers Planorbulinids Biostratigraphy Qom Formation Central Iran

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Quantification of grain boundary effects on the geometrically necessary dislocation density evolution and strain hardening of polycrystalline Mg-4Al using in situ tensile testing in scanning electron microscope and HR-EBSD

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Journal of Magnesium and Alloys 2024年第5期12卷 1815-1829页

作者： Eunji Song mohsen Taheri Andani Amit Misra Department of Materials Science and Engineering University of MichiganAnn ArborMI 48109USA Department of Mechanical Engineering University of MichiganAnn ArborMI 48109USA Department of Mechanical Engineering Texas A&M UniversityCollege StationTX 77843USA

In situ tensile testing in a scanning electron microscope(SEM)in conjunction with high-resolution electron backscatter diffraction(HR-EBSD)under load was used to characterize the evolution of geometrically necessary dislocation(GND)densities at individual grain boundaries as a function of applied strain in a polycrystalline Mg-4Al *** increase in GND density was investigated at plastic strains of 0%,0.6%,2.2%,3.3% from the area including 76 grains and correlated with(i)geometric compatibility between slip systems across grain boundaries,and(ii)plastic *** develop expressions for the grain boundary GND density evolution as a function of plastic strain and plastic incompatibility,from which uniaxial tensile stress-strain response of polycrystalline Mg-4Al are computed and compared with experimental *** findings in this study contribute to understanding the mechanisms governing the strain hardening response of single-phase polycrystalline alloys and more reliable prediction of mechanical behaviors in diverse microstructures.

关键词： Mg-Al alloys Grain boundaries Geometrically necessary dislocations Strain gradient plasticity HR-EBSD

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Design of Protograph LDPC-Coded MIMO-VLC Systems with Generalized Spatial Modulation

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China Communications 2024年第3期21卷 118-136页

作者： Dai Lin Fang Yi Guan Yongliang mohsen Guizani School of Information Engineering Guangdong University of TechnologyGuangzhou 51006China The State Key Laboratory of Integrated Services Networks Xidian UniversityXi’an 710126China School of Electrical and Electronic Engineering Nanyang Technological UniversitySingapore Department of Machine Learning Mohamed Bin Zayed University of Artificial Intelligence(MBZUAI)Abu DhabiUnited Arab Emirates

This paper investigates the bit-interleaved coded generalized spatial modulation(BICGSM) with iterative decoding(BICGSM-ID) for multiple-input multiple-output(MIMO) visible light communications(VLC). In the BICGSM-ID scheme, the information bits conveyed by the signal-domain(SiD) symbols and the spatial-domain(SpD) light emitting diode(LED)-index patterns are coded by a protograph low-density parity-check(P-LDPC) code. Specifically, we propose a signal-domain symbol expanding and re-allocating(SSER) method for constructing a type of novel generalized spatial modulation(GSM) constellations, referred to as SSERGSM constellations, so as to boost the performance of the BICGSM-ID MIMO-VLC ***, by applying a modified PEXIT(MPEXIT) algorithm, we further design a family of rate-compatible P-LDPC codes, referred to as enhanced accumulate-repeat-accumulate(EARA) codes,which possess both excellent decoding thresholds and linear-minimum-distance-growth property. Both analysis and simulation results illustrate that the proposed SSERGSM constellations and P-LDPC codes can remarkably improve the convergence and decoding performance of MIMO-VLC systems. Therefore, the proposed P-LDPC-coded SSERGSM-mapped BICGSMID configuration is envisioned as a promising transmission solution to satisfy the high-throughput requirement of MIMO-VLC applications.

关键词： bit-interleaved coded modulation generalized spatial modulation multiple-input multipleoutput protograph LDPC codes visible light communication

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On the Relation Between Symmetry of Radio Galaxies and Their Physical Parameters

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Research in Astronomy and Astrophysics 2024年第9期24卷 37-59页

作者： mohsen Javaherian Halime Miraghaei Hooman Moradpour Research Institute for Astronomy and Astrophysics of Maragha(RIAAM) University of MaraghehP.O.Box 55136-553MaraghehIran

Gravity as a fundamental force plays a dominant role in the formation and evolution of cosmic objects and leaves its effect in the emergence of symmetric and asymmetric ***,analyzing the symmetry criteria allows us to uncover mechanisms behind the gravity interaction and understand the underlying physical processes that contribute to the formation of large-scale structures such as *** use a segmentation process using intensity thresholding and the k-means clustering algorithm to analyze radio galaxy *** employ a symmetry criterion and explore the relation between morphological symmetry in radio maps and host galaxy *** properties(stellar mass,black hole mass,optical size(R_(50)),concentration,stellar mass surface density(μ_(50)),and stellar age)and radio properties(radio flux density,radio luminosity,and radio size)are *** found that there is a correlation between symmetry and radio size,indicating larger radio sources have smaller symmetry ***,size of radio sources should be considered in any investigation of *** correlations are also observed with other properties,such as R_(50)for FRI galaxies and stellar *** compare the symmetry differences between FRI and FRII radio *** galaxies show higher symmetry in 1.4 GHz and 150 MHz *** the influence of radio source sizes,we discovered that this result is independent of the sizes of radio *** findings contribute to our understanding of the morphological properties and analyses of radio galaxies.

关键词： methods:data analysis techniques:image processing catalogs galaxies:nuclei galaxies:distances and redshifts

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Energy-efficient joint UAV secure communication and 3D trajectory optimization assisted by reconfigurable intelligent surfaces in the presence of eavesdroppers

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Defence Technology（防务技术） 2024年第1期31卷 537-543页

作者： Huang Hailong mohsen Eskandari Andrey V.Savkin Wei Ni The Department of Aeronautical and Aviation Engineering The Hong Kong Polytechnic UniversityHong KongChina School of Electrical Engineering and Telecommunications University of New South WalesSydney2052Australia Data61 CSIROAustralia

We consider a scenario where an unmanned aerial vehicle(UAV),a typical unmanned aerial system(UAS),transmits confidential data to a moving ground target in the presence of multiple *** friendly reconfigurable intelligent surfaces(RISs) help to secure the UAV-target communication and improve the energy efficiency of the *** formulate an optimization problem to minimize the energy consumption of the UAV,subject to the mobility constraint of the UAV and that the achievable secrecy rate at the target is over a given *** present an online planning method following the framework of model predictive control(MPC) to jointly optimize the motion of the UAV and the configurations of the *** effectiveness of the proposed method is validated via computer simulations.

关键词： Unmanned aerial systems(UASs) Unmanned aerial vehicle(UAV) Communication security Eaves-dropping Reconfigurable intelligent surfaces(RIS) Autonomous navigation and placement Path planning Model predictive control

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