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Thermodynamic modeling of Fe-C-Mn-Si alloys

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Journal of Iron and Steel Research International 2017年第2期24卷 190-197页

作者： Wei-sen Zheng Xiao-gang Lu yan-lin he lin Li School of Materials Science and Engineering Shanghai University Shanghai 200444 China Department of Materials Science and Engineering KTH Royal Institute of Technology Stockholm 10044 Sweden State Key Laboratory of Advanced Special Steel Shanghai University Shanghai 200072 China

The thermodynamic database of the Fe C Mn-Si system has been developed in the framework of the CALPHAD approach. The sub-ternary systems have been carefully evaluated and revised based on available experimental data. A satisfactory description of the liquid phase in the Fe C-Si system has been obtained. The C Mn Si system was assessed treating the liquid phase as a substitutional solution. Phase equilibria in the C- Mn-Si system, especially those involving the liquid phase, can be well described. Based on the extrapolation of the experimental data in the quaternary system, the Fe Mn Si system has been modified to agree well with experimental data at high temperatures. The comparison between the calculated and measured phase transformation tempera tures confirms the reliability of the present quaternary database. Additionally, the solidification process of Fe-0. 16C-1. 5Mn-1. 5Si （wt. %） alloy was simulated by using the thermodynamic database developed.

关键词： Fe-C-Mn-Si alloy Thermodynamic mode CALPHAD Solidification Partial equilibrium

Response Characteristics and Adiabatic heating during High Strain Rate for TRIP Steel and DP Steel

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Journal of Iron and Steel Research International 2015年第1期22卷 48-54页

作者： Yi GAO Chao XU Zhong-ping he yan-lin he lin LI School of Materials Science and Engineering Shanghai University

By using a static and high-speed material testing machine, tensile deformation behaviors of two kinds of Si- Mn TRIP （transformation induced plasticity） steels and DP （dual phase） steel were studied in a large range of strain rates （0.001-2000 s 1）. Temperature variation during adiabatic heating and the amount of retained austenite at fracture were measured by an infrared thermometer and an Xray stress analyser, respectively. The microstructure of steels was observed by optical microscopy （OM） and scanning electron microscopy （SEM） before and after tensile test. It was found from the experimental results that the tensile strength of these steels increased, and the fracture elonga- tion firstly decreased and subsequently increased, as the strain rate increased in the range ＂of 0.1 - 2000 s -1. The temperature raised during adiabatic heating of TRIP steel was in the range of 100- 300℃, while that of the DP steel was in the range of 100-220℃ . The temperature rise of these steels increased with increasing the strain rate, as well as the amount of the transformed retained austenite in TRIP steels. It was confirmed that austenite to martensite transformation is not suppressed by adiabatic heating.

关键词： strain rate TRIP steel adiabatic heating retained austenite

Cyproheptadine Regulates Pyramidal Neuron Excitability in Mouse Medial Prefrontal Cortex

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Neuroscience Bulletin 2018年第5期34卷 759-768页

作者： yan-lin he Kai Wang Qian-Ru Zhao yan-Ai Mei Institutes of Brain Science State Key Laboratory of Medical Neurobiology and School of Life Sciences Fudan University

Cyproheptadine （CPH）, a first-generation anti- histamine, enhances the delayed rectifier outward K＋ current （IK） in mouse cortical neurons through a sigma-1 receptor-mediated protein kinase A pathway. In this study, we aimed to determine the effects of CPH on neuronal excitability in current-clamped pyramidal neurons in mouse medial prefrontal cortex slices. CPH （10 μmol/L） significantly reduced the current density required to generate action potentials （APs） and increased the instan- taneous frequency evoked by a depolarizing current. CPH also depolarized the resting membrane potential （RMP）, decreased the delay time to elicit an AP, and reduced the spike threshold potential. This effect of CPH was mim- icked by a sigma-1 receptor agonist and eliminated by an antagonist. Application of tetraethylammonium （TEA） to block IK channels hyperpolarized the RMP and reduced the instantaneous frequency of APs. TEA eliminated the effects of CPH on AP frequency and delay time, but had no effect on spike threshold or RMP. The current-voltage relationship showed that CPH increased the membrane depolarization in response to positive current pulses and hyperpolarization in response to negative current pulses, suggesting that other types of membrane ion channels might also be affected by CPH. These results suggest that CPH increases the excitability of medial prefrontal cortex neurons by regulating TEA-sensitive IK channels as well as other TEA-insensitive K＋ channels, probably ID and inward-rectifier Kir channels. This effect of CPH may explain its apparent clinical efficacy as an antidepressant and antipsychotic.

关键词： Cyproheptadine Neuronal excitability Te-traethylammonium-sensitive Ik cortical neurons Sigma-1 receptor

Microstructures and mechanical properties of ferrite-based lightweight steel with different compositions

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Journal of Iron and Steel Research International 2017年第7期24卷 737-742页

作者： Reng-chong Xu yan-lin he Hu Jiang Hua Wang Na-qiong Zhu Xiao-gang Lu lin Li School of Materials Science and Engineering Shanghai University State Key Laboratory of Advanced Special Steel Shanghai University Instrumental Analysis & Research Center Shanghai University Materials Genome Institute Shanghai University

The microstructures and mechanical properties of ferrite-based lightweight steel with different compositions were investigated by tensile test,scanning electron microscopy（SEM）,transmission electron microscopy（TEM）,X-ray diffraction（XRD）and thermodynamic calculation（TC）.It was shown that the ferrite-based lightweight steels with 5wt.%or 8wt.%Al were basically composed of ferrite,austenite andκ-*** the annealing temperature increased,the content of the austenite in the steel gradually increased,while theκ-carbide gradually decomposed and finally *** mechanical properties of the steel with 5wt.%Al and 2wt.%Cr,composed of ferrite and Cr7C3carbide at different annealing temperatures,were significantly inferior to those of *** steel containing 5wt.%Al,annealed at 820°C for 50sthen rapidly cooled to 400°C and held for 180s,can obtain the best product of strength and elongation（PSE）of 31242MPa·%.The austenite stability of the steel is better,and its PSE is *** addition,the steel with higher PSE has a more stable instantaneous strain hardening exponent（n value）,which is mainly caused by the effect of transformation induced plasticity（TRIP）.When theκ-carbide or Cr7C3carbide existed in the microstructure of the steel,there was an obvious yield plateau in the tensile curve,while its PSE decreased significantly.

关键词： Ferrite-based lightweight steel Microstructure Mechanical property Transformation induced plasticity effect κ-carbide

CALPHAD modeling of molar volume

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Chinese Science Bulletin 2014年第15期59卷 1646-1651页

作者： yan-lin he Xiao-Gang Lu Na-Qiong Zhu Bo Sundman School of Materials Science and Engineering Shanghai University CEA Saclay INSTN Gif-sur-Yvette 91191 France

Databases concerning basic physical properties of materials,such as molar volume,density,thermal expansion coefficient,elastic constants,thermal conductivity,etc.,are essential parts of the underlying knowledge for materials *** thermodynamic databases provide chemical driving forces and phase equilibrium data,physical property databases provide essential physical parameters,such as volume,lattice constant,lattice misfit,elastic energy,interfacial energy,etc.,for phase transformation and microstructure *** with thermodynamic databases,physical property databases established on the basis of the calculation of phase diagram(CALPHAD)method can be used to calculate physical properties together with phase equilibria,phase fractions,phase compositions,and thermodynamic properties for multi-component and multi-phase material systems and for the constituent *** this paper,we will discuss in detail various volume models based on the CALPHAD method which are capable of describing experimental data in a wide range from cryogenic temperatures to melting points,from the atmospheric pressure to high pressures for pure substances as well as multi-component and multiphase materials.

关键词：计算模型摩尔体积相图计算热力学数据库相平衡数据属性数据库物理性质材料设计

Experimental study of phase equilibria on Co-Fe-rich side of Co-Al-Fe system

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Journal of Iron and Steel Research International 2020年第6期27卷 673-680页

作者： Jing-jing Wang Wei-sen Zheng Xiao-gang Lu yan-lin he Qing-rong Yao Jiang Wang School of Materials Science and Engineering Shanghai UniversityShanghai 200444China Materials Genome Institute Shanghai UniversityShanghai200444China State Key Laboratory of Advanced Special Steel Shanghai UniversityShanghai200444China School of Materials Science and Engineering Guilin University of Electronic TechnologyGuilin 541004GuangxiChina

Despite various studies on Co-Al-Fe ternary system, its phase equilibria are still in doubt. Phase equilibria, magnetic transition and bcc_A2/bcc_B2 order-disorder transformation at the Co-Fe-rich side of the Co-Al-Fe alloys were carefully investigated by means of electron probe microanalysis (EPMA), X-ray diffraction (XRD) and differential scanning calo-rimetry. The equilibrium phases and their compositions were determined by 18 alloy samples annealed at 900, 1000, 1100 and 1200℃ for 528, 336, 168 and 96h, respectively, followed by quenching. However, by adopting the above traditional method, bcc_A2 and fcc_A1 phases are difficult to be distinguished through XRD analysis at room temperature due to the martensitic transformation of fcc_A1 phase during quenching. For this reason, high-temperature insitu XRD technique was utilized to correctly establish the phase relationships among bcc_A2, bcc_B2 and fcc_A1 phases. The phase transformation between bcc_A2 and B2 phases was determined to be second order instead of first order at temperatures higher than 900℃. The equilibrium phases and compositions were further confirmed by fabricating 16 diffusion couples together with EPMA. Meanwhile, using three-dimensional differential scanning calorimetry method, bcc_A2/B2 and ferro-/paramagnetic transi-tions were determined with high accuracy.

关键词： Co-Al-Fe system Phase equilibrium Martensitic transformation Order-disorder transition

In-situ analysis of retained austenite transformation in high-performance micro-alloyed TRIP steel

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Journal of Iron and Steel Research International 2017年第3期24卷 313-320页

作者： Ji-bo Peng Hu Jiang Gong-ting Zhang Li-ben Chen Na-qiong Zhu yan-lin he Xiao-gang Lu lin Li School of Materials Science and Engineering Shanghai University Shanghai 200072 China State Key Laboratory of Advanced Special Steel Shanghai University Shanghai 200072 China Pangang Group Research Institute Panzhihua 617000 Sichuan China

Microstructures and mechanical properties of Ti-V micro-alloyed TRIP（ transformation-induced plasticity） steel with different compositions were investigated by tensile test,scanning electron microscopy（ SEM）,transmission electron microscopy（ TEM）,X-ray diffraction（ XRD） and thermodynamic calculation（ TC）. The results indicated that the steel exhibited high ultimate tensile strength（ 1 079MPa）,sufficient ductility（ 28%） and the highest product of strength and ductility（ 30 212 MPa·%） heat treated after intercritical annealing at 800℃ for 3 min and bainitic annealing at 430 ℃ for 5 min. In addition,the change of volume fraction of retained austenite（ VF-RA） versus tensile strain was measured using in-situ analysis by X-ray stress apparatus and micro-electronic universal testing machine. It was concluded that a-value could be used to evaluate the stability of retained austenite（ S-RA） in the investigated Ti-V micro-alloyed TRIP steel. The smaller a-value indicated the higher stability of retained austenite（ S-RA） and the higher mechanical properties of Ti-V micro-alloyed TRIP steel.

关键词： Ti-V micro-alloyed TRIP steel Retained austenite stability In-situ analysis Microstructure

Prediction of solar activities:Sunspot numbers and solar magnetic synoptic maps

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Science China Earth Sciences 2024年第8期67卷 2460-2477页

作者： Rui ZHUO Jiansen he Die DUAN Rong lin Ziqi WU Limei yan Yong WEI School of Earth and Space Sciences Peking UniversityBeijing 100091China College of Advanced Interdisciplinary Studies National University of Defense TechnologyChangsha 410073China Centre for Mathematical Plasma Astrophysics Department of MathematicsKU LeuvenLeuven 3001Belgium Key Laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China

The evolution of solar magnetic fields is significant for understanding and predicting solar *** our knowledge of solar magnetic fields largely depends on the photospheric magnetic *** this paper,based on the spherical harmonic expansion of the photospheric magnetic field observed by Wilcox Solar Observatory,we analyze the time series of spherical harmonic coefficients and predict Sunspot Number as well as synoptic maps for Solar Cycle *** find that solar maximum years have complex short-period disturbances,and the time series of coefficient g_(7)~0 is nearly in-phase with Sunspot Number,which may be related to solar meridional *** Long Short-Term Memory networks(LSTM),our prediction suggests that the maximum of Solar Cycle 25 is likely to occur in June 2024 with an error of 8 months,the peak sunspot number may be 166.9±22.6,and the next solar minimum may occur around January *** incorporating Empirical Mode Decomposition,we enhance our forecast of synoptic maps truncated to Order 5,validating their relative *** prediction not only addresses a gap in forecasting the global distribution of the solar magnetic field but also holds potential reference value for forthcoming solar observation plans.

关键词： Solar activity prediction Solar magnetic field Spherical harmonic expansion Long-Short Term Memory(LSTM) Empirical Mode Decomposition(EMD)

Hybrid Hierarchical Particle Swarm Optimization with Evolutionary Artificial Bee Colony Algorithm for Task Scheduling in Cloud Computing

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Computers, Materials & Continua 2024年第1期78卷 1135-1156页

作者： Shasha Zhao Huanwen yan Qifeng lin Xiangnan Feng he Chen Dengyin Zhang College of Internet of Things Nanjing University of Posts and TelecommunicationsNanjing210003China Jiangsu Key Laboratory of Broadband Wireless Communication and Internet of Things Nanjing University of Posts and TelecommunicationsNanjing210003China Tongding Interconnection Information Co. Ltd.Suzhou215000China

Task scheduling plays a key role in effectively managing and allocating computing resources to meet various computing tasks in a cloud computing *** execution time and low load imbalance may be the challenges for some algorithms in resource scheduling *** this work,the Hierarchical Particle Swarm Optimization-Evolutionary Artificial Bee Colony Algorithm(HPSO-EABC)has been proposed,which hybrids our presented Evolutionary Artificial Bee Colony(EABC),and Hierarchical Particle Swarm Optimization(HPSO)*** HPSO-EABC algorithm incorporates both the advantages of the HPSO and the EABC *** testing including evaluations of algorithm convergence speed,resource execution time,load balancing,and operational costs has been *** results indicate that the EABC algorithm exhibits greater parallelism compared to the Artificial Bee Colony *** with the Particle Swarm Optimization algorithm,the HPSO algorithmnot only improves the global search capability but also effectively mitigates getting stuck in local *** a result,the hybrid HPSO-EABC algorithm demonstrates significant improvements in terms of stability and convergence ***,it exhibits enhanced resource scheduling performance in both homogeneous and heterogeneous environments,effectively reducing execution time and cost,which also is verified by the ablation experimental.

关键词： Cloud computing distributed processing evolutionary artificial bee colony algorithm hierarchical particle swarm optimization load balancing