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A deep learning interatomic potential suitable for simulating radiation damage in bulk tungsten

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Tungsten 2024年第2期6卷 304-322页

作者： Chang-Jie Ding Ya-Wei Lei Xiao-yang Wang Xiao-lin li xiang-yan li yan-Ge Zhang Yi-Chun Xu Chang-Song liu Xue-Bang Wu Key Laboratory of Materials Physics Institute of Solid State PhysicsHFIPSChinese Academy of SciencesHefei 230031China Science Island University of Science and Technology of ChinaHefei 230026China Laboratory of Computational Physics Institute of Applied Physics and Computational MathematicsBeijing 100088China

So far, it has been a challenge for existing interatomic potentials to accurately describe a wide range of physical properties and maintain reasonable efficiency. In this work, we develop an interatomic potential for simulating radiation damage in body-centered cubic tungsten by employing deep potential, a neural network-based deep learning model for representing the potential energy surface. The resulting potential predicts a variety of physical properties consistent with first-principles calculations, including phonon spectrum, thermal expansion, generalized stacking fault energies, energetics of free surfaces, point defects, vacancy clusters, and prismatic dislocation loops. Specifically, we investigated the elasticity-related properties of prismatic dislocation loops, i.e., their dipole tensors, relaxation volumes, and elastic interaction energies. This potential is found to predict the maximal elastic interaction energy between two 1/2 loops better than previous potentials, with a relative error of only 7.6%. The predicted threshold displacement energies are in reasonable agreement with experimental results, with an average of 128 eV. The efficiency of the present potential is also comparable to the tabulated gaussian approximation potentials and modified embedded atom method potentials, meanwhile, can be further accelerated by graphical processing units. Extensive benchmark tests indicate that this potential has a relatively good balance between accuracy, transferability, and efficiency.

关键词： Machine learning Deep learning Interatomic potential Radiation damage Tungsten

Versatile and controlled quantum teleportation network

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Chinese Physics B 2024年第3期33卷 415-423页

作者：周瑶瑶梅鹏娴刘艳红吴量李雁翔闫智辉贾晓军 Department of Physics Taiyuan Normal UniversityJinzhong 030619China College of Information Engineering Shanxi Vocational University of Engineering Science and TechnologyJinzhong 030619China Shanxi North Machinery Manufacturing Co. LtdTaiyuan 030000China State Key Laboratory of Quantum Optics and Quantum Optics Devices Institute of Opto-ElectronicsShanxi UniversityTaiyuan 030006China Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuan 030006China

A quantum teleportation network involving multiple users is essential for future quantum *** far,controlled quantum teleportation has been demonstrated in a three-user ***,versatile and controlled quantum teleportation network involving more users is in demand,which satisfies different combinations of users for practical *** we propose a highly versatile and controlled teleportation network that can switch among various combinations of different *** use a single continuous-variable six-partite Greenberger-Horne-Zeilinger(GHZ)state to realize such a task by choosing the different measurement and feedback *** controlled teleportation network,which includes one sub-network,two sub-networks and three sub-networks,can be realized for different application of user ***,the coherent feedback control(CFC)can manipulate and improve the teleportation *** approach is flexible and scalable,and would provide a versatile platform for demonstrations of complex quantum communication and quantum computing protocols.

关键词： quantum teleportation coherent feedback control versatile controlled transformation

Development of new ductile iron with super-high thermal conductivity and elongation

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Journal of Iron and Steel Research International 2022年第3期29卷 462-473页

作者： Guang-hua Wang yan-xiang li School of Materials Science and Engineering Tsinghua UniversityBeijing100084China Key Laboratory for Advanced Materials Processing Technology Ministry of EducationBeijing100084China

The effects of Si content,graphite volume fraction and pearlite volume fraction on the thermal conductivity of ductile iron were studied based on theoretical model *** results showed that the thermal conductivity of ductile iron was more sensitive to Si content compared with the volume fractions of pearlite and *** key method to design and develop high thermal conductivity ductile iron was to control the Si *** 0.9-2.2 wt.%Si content,experimental results showed that with the increase in Si content,the thermal conductivity of ductile iron decreased dramatically,and the yield strength and tensile strength of ductile iron almost linearly increased,but the elongation remained almost *** dependence of thermal conductivity of ductile iron on temperature changed from monotonic decreasing to increasing first and then ***,we broke the common composition range of ductile iron and designed a new high C(≥3.9 wt.%)and low Si(1.0-1.4 wt.%)ductile iron with super-high thermal conductivity and *** thermal conductivity exceeded 40 W/(m K)within 27-300℃,and maintained at 35-40 W/(m K)at 500℃.The elongation was over 25%,and the tensile strength was more than 300 MPa.

关键词： Thermal conductivity Ductile iron Elongation Tensile strength Silicon alloying

Different thermal fatigue behaviors between gray cast iron and vermicular graphite cast iron

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China Foundry 2022年第3期19卷 245-252页

作者： Gui-quan Wang Zhong-li liu yan-xiang li xiang Chen School of Nuclear Equipment and Nuclear Engineering Yantai UniversityYantai 264005ShandongChina School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China Key Laboratory for Advanced Materials Processing Technology Ministry of EducationTsinghua UniversityBeijing 100084China

The initiation and propagation of thermal fatigue cracks in gray cast iron and vemicular graphite cast iron were investigated by Uddeholm method to reveal the complex thermal fatigue behaviors of cast *** of thermal fatigue behaviors of gray cast iron and vemicular graphite cast iron were observed and *** is found that the observed differences are related to the combination of graphite morphology and the oxidization of *** oxidized matrix is observed in gray cast iron due to its large specific surface *** brittle oxidized matrix facilitates the propagation of microcracks along the oxidization *** contrast,the radial microcracks are formed in vermicular graphite at the edge of graphite due to fewer oxidization *** indicates that the thermal fatigue resistance of gray cast iron is dominated by graphite content and morphology while that of vermicular graphite cast iron strongly relates to the strength of the matrix.

关键词： thermal fatigue gray cast iron vermicular graphite cast iron oxidization cracking propagation

Thermal conductivity of cast iron-A review

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China Foundry 2020年第2期17卷 85-95页

作者： Guang-hua Wang yan-xiang li School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China Key Laboratory for Advanced Materials Processing Technology Ministry of EducationBeijing 100084China

This paper gives a brief introduction to the four research methods for the study on thermal conductivity of cast irons,including experimental measurement,statistical analysis,effective medium theory and numerical *** studies on the thermal conductivity of various cast irons are reviewed through the influence of alloying elements,structural constituents,and *** addition of alloying elements is the main reason that restricts the thermal conductivity of cast irons,especially spheroidal graphite cast *** connectivity of graphite has a significant effect on the thermal conductivity of flake and compacted graphite cast irons,semiquantitative and quantitative analysis of this factor is a key and difficult point in the study of thermal conductivity of cast *** thermal conductivities of different types of cast irons show varying degrees of dependence on *** phenomenon is the combination of graphite and matrix,rather than just depending on graphite *** study of the relationship between individual phase and temperature is the focus of future *** summaries and discussions may provide reference and guidance for the future research and development of high thermal conductivity cast irons.

关键词： cast iron thermal conductivity gray cast iron nodular castiron compacted graphite cast iron

Calculating the effective thermal conductivity of gray cast iron by using an interconnected graphite model

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China Foundry 2020年第3期17卷 183-189页

作者： Guang-hua Wang yan-xiang li School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China Key Laboratory for Advanced Materials Processing Technology Ministry of EducationBeijing 100084China

A new theoretical model of gray cast iron taking into account a locally interconnected structure of flake graphite was designed,and the corresponding effective thermal conductivity was calculated using the thermal resistance network *** calculated results are obviously higher than that of the effective medium approximation assuming that graphite is distributed in *** is suggested that the interconnected structure significantly enhances the overall thermal ***,it is shown that high anisotropy of graphite thermal conductivity,high volume fraction of graphite,and small aspect ratio of flake graphite will cause the connectivity effects of graphite to more obviously improve the overall thermal *** graphite volume fraction,lower aspect ratio and higher matrix thermal conductivity are beneficial to obtain a high thermal conductivity gray cast *** work can provide guidance and reference for the development of high thermal conductivity gray cast iron and the design of high thermal conductivity composites with similar locally interconnected structures.

关键词： gray cast iron effective thermal conductivity flake graphite interconnected graphite structure

Fuzzy neural network analysis on gray cast iron with high tensile strength and thermal conductivity

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China Foundry 2019年第3期16卷 190-197页

作者： Gui-quan Wang xiang Chen yan-xiang li School of Materials Science and Engineering Tsinghua University Beijing 100084 China Key Laboratory for Advanced Materials Processing Technology Ministry of Education Beijing 100084 China

To develop a high performance gray cast iron with high tensile strength and thermal conductivity, multivariable analysis of microstructural effects on properties of gray cast iron was performed. The concerned parameters consisted of graphite content, maximum graphite length, primary dendrite percentage and microhardness of the matrix. Under the superposed influence of various parameters, the relationships between thermal conductivity and structural characteristics become irregular, as well as the effects of graphite length on the strength. An adaptive neuro-fuzzy inference system was built to link the parameters and properties. A sensitivity test was then performed to rank the relative impact of parameters. It was found that the dominant parameter for tensile strength is graphite content, while the most relative parameter for thermal conductivity is maximum graphite length. The most effective method to simultaneously improve the tensile and thermal conductivity of gray cast iron is to reduce the carbon equivalent and increase the length of graphite flakes.

关键词： high performance gray cast iron fuzzy neural network tensile strength thermal conductivity

Effects of alloying elements on thermal conductivity of pearlitic gray cast iron

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Journal of Iron and Steel Research International 2019年第9期26卷 1022-1030页

作者： Gui-quan Wang xiang Chen yan-xiang li Yuan liu Hua-wei Zhang Zhong-li liu School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China School of Nuclear Equipment and Nuclear Engineering Yantai UniversityYantai 264005ShandongChina Key Laboratory for Advanced Materials Processing Technology Tsinghua UniversityBeijing 100084China

A quantitative model is proposed to describe the thermal conductivity of alloyed pearlitic gray cast iron. The model is built by combining the computational thermodynamics and effective medium theory. The volume fractions and concentrations of precipitated phases in as-cast structure are estimated in consideration of partial and para-equilibrium. The conductivity of alloyed ferrite is calculated, taking into account the electronic and vibrational contributions of alloying elements. The model provides a good agreement with microstructure analysis and measured thermal conductivity. The influence of common alloying elements was discussed from the viewpoint of precipitation of phases and scattering of alloying atoms. This model can also be used as a numerical tool for designing the pearlitic gray cast irons with high thermal conductivity and high tensile strength.

关键词： Thermal conductivity Thermodynamic model Gray cast iron Alloying element

Comparison of 1.5% lidocaine and 0.5% ropivacaine epidural anesthesia combined with propofol general anesthesia guided by bispectral index

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2007年第6期8卷 428-434页

作者： xiang yan li Yu-hong Department of Anesthesiology the First Affiliated Hospital School of Medicine Zhejiang University Hangzhou 310003 China

Objective： To compare the effects of epidural anesthesia with 1.5% lidocaine and 0.5% ropivacaine on propofol requirements, the time to loss of consciousness （LOC）, effect-site propofol concentrations, and the hemodynamic variables during induction of general anesthesia guided by bispectral index （BIS） were studied. Methods： Forty-five patients were divided into three groups to receive epidurally administered saline （Group S）, 1.5% （w/w） lidocaine （Group L）, or 0,5% （w/w） ropivacaine （Group R） Propofol infusion was started to produce blood concentration of 4 lag/ml. Once the BIS value reached 40-50, endotracheal intubation was facilitated by 0.1 mg/kg vecuronium. Measurements included the time to LOC, effect-site propofol concentrations, total propofol dose, mean arterial blood pressure （MABP）, and heart rate （HR） at different study time points. Results： During induction of anesthesia, both Groups L and R were similar for the time to LOC, effect-site propofol concentrations, total propofol dose, MABP, HR, and BIS. The total doses of propofol administered until 1 min post-intubation were significantly less in patients of Groups R and L compared with Group S. MABP and HR were significantly lower following propofol induction compared with baseline values in the three groups, or MABP was significantly increased following intubation as compared with that prior to intubation in Group S but not in Groups R and L while HR was significantly increased following intubation in the three groups. Conclusion： Epidural anesthesia with 1.5% lidocaine and 0.5% ropivacaine has similar effects on the time to LOC, effect-site propofol concentrations, total propofol dose, and the hemodynamic variables during induction of general anesthesia.

关键词： Propofol lidocaine Ropivacaine Epidural anethesia Bispectral index