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Effects of Sub-zero Celsius Treatment and Tempering on the Stability of Retained Austenite in Bearing Steel

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Acta Metallurgica Sinica(English Letters) 2015年第6期28卷 787-792页

作者： xiao-hui lu Wei Li Cheng-Lin Wang Hong-Shan Zhao Xue-Jun Jin State Key Lab of Metal Matrix Composite School of Materials Science and Engineering Shanghai Jiao Tong University Institute of Advanced Steels and Materials School of Materials Science and Engineering Shanghai Jiao Tong University

In this work, the influence of sub-zero Celsius treatment and tempering on the mechanical and thermal stability of retained austenite in beating steel were assessed by tensile test and DSC. Compared with traditional quenched and tempered treatment, sub-zero Celsius treatment obviously decreases the volume fraction of retained austenite. Moreover, the mechanical stability of retained austenite was enhanced due to the accumulation of compressive stresses in retained austenite after sub-zero Celsius treatment and tempering. Meanwhile, the morphology of retained austenite changed from film-like to blocky with austenitization temperature increasing, and the mechanical stability of film-like retained austenite is higher than that of blocky one. The DSC results showed that the activation energy of retained austenite decomposition slightly increased through sub-zero Celsius treatment and tempering. This result may probably be ascribed to partitioning of carbon during tempering. However, the temperature at which retained austenite starts to decompose is unchanged.

关键词： Bearing steel Sub-zero Celsius treatment Retained austenite Stability

Life Prediction of Newly Developed Ferritic Stainless Steels for Automotive Muffler

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Journal of Iron and Steel Research International 2014年第1期21卷 125-130页

作者： Chao CHEN Yue ZHENG Yue ZHANG xiao-hui lu Cheng-jia SHANG Nuclear Equipment Division CNNC China Nuclear Power Engineering Co.Ltd. School of Materials Science and Engineering University of Science and Technology Beijing Nuclear and Radiation Safety Center MEP

Corrosion mechanism of automotive mufflers was investigated by SEM （scanning electron microscope） and XRD （X-ray diffractomer） analysis. 409L and newly developed 439M steels were evaluated in terms of condensate corrosion tests for 5 periods, 10 periods and 20 periods separately. The relative lifetimes of 409L and 439M steels were predicted according to the extreme value analysis method and pitting corrosion models. Modelling studies dem- onstrated that the predicted relative lifetime of 439M ferrite stainless steel is 6.8 times that of 409L steels. The extreme value analysis method was also successfully used in the road test. The estimated maximum corrosion depth of the 439M muffler is 0. 55 ram.

关键词： stainless steel SEMi XRD modelling study pitting corrosion

Numerical and experimental study on the falling film flow characteristics with the effect of co-current gas flow in hydrogen liquefaction process

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Petroleum Science 2024年第2期21卷 1369-1384页

作者： Chong-Zheng Sun Yu-Xing Li hui Han xiao-Yi Geng xiao lu College of Energy Storage Technology Shandong University of Science and TechnologyQingdao 266590ShandongChina College of Pipeline and Civil Engineering/Shandong Provincial Key Laboratory of Oil&Gas Storage and Transportation Safety China University of PetroleumQingdao 266580ShandongChina

Liquid hydrogen storage and transportation is an effective method for large-scale transportation and utilization of hydrogen energy. Revealing the flow mechanism of cryogenic working fluid is the key to optimize heat exchanger structure and hydrogen liquefaction process(LH2). The methods of cryogenic visualization experiment, theoretical analysis and numerical simulation are conducted to study the falling film flow characteristics with the effect of co-current gas flow in LH2spiral wound heat *** results show that the flow rate of mixed refrigerant has a great influence on liquid film spreading process, falling film flow pattern and heat transfer performance. The liquid film of LH2mixed refrigerant with column flow pattern can not uniformly and completely cover the tube wall surface. As liquid flow rate increases, the falling film flow pattern evolves into sheet-column flow and sheet flow, and liquid film completely covers the surface of tube wall. With the increase of shear effect of gas-phase mixed refrigerant in the same direction, the liquid film gradually becomes unstable, and the flow pattern eventually evolves into a mist flow.

关键词： Hydrogen liquefaction Spiral wound heat exchanger Flow pattern transition Falling film flow

Deep learning for automatically predicting early haematoma expansion in Chinese patients

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Stroke & Vascular Neurology 2021年第4期6卷 610-614,I0067-I0072页

作者： Jia-wei Zhong Yu-jia Jin Zai-jun Song Bo Lin xiao-hui lu Fang Chen lu-sha Tong Department of Neurology Zhejiang University School of Medicine Second Affiliated HospitalHangzhouChina College of Computer Science and Technology Zhejiang UniversityHangzhouChina State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang University School of Mechanical EngineeringHangzhouChina Department of Computer Science and Engineering Nanjing University of Aeronautics and AstronauticsNanjingChina

Background and purpose Early haematoma expansion is determinative in predicting outcome of intracerebral haemorrhage(ICH)*** aims of this study are to develop a novel prediction model for haematoma expansion by applying deep learning model and validate its prediction *** Data of this study were obtained from a prospectively enrolled cohort of patients with primary supratentorial ICH from our *** developed a deep learning model to predict haematoma expansion and compared its performance with conventional non-contrast CT(NCCT)*** evaluate the predictability of this model,it was also compared with a logistic regression model based on haematoma volume or the BAT *** A total of 266 patients were finally included for analysis,and 74(27.8%)of them experienced early haematoma *** deep learning model exhibited highest C statistic as 0.80,compared with 0.64,0.65,0.51,0.58 and 0.55 for hypodensities,black hole sign,blend sign,fluid level and irregular shape,*** the C statistics for swirl sign(0.70;p=0.211)and heterogenous density(0.70;p=0.141)were not significantly higher than that of the deep learning ***,the predictive value for the deep learning model was significantly superior to that of the logistic model of haematoma volume(0.62;p=0.042)and the BAT score(0.65;p=0.042).Conclusions Compared with the conventional NCCT markers and BAT predictive model,the deep learning algorithm showed superiority for predicting early haematoma expansion in ICH patients.

关键词： patients expansion predicting

Buckling Properties of Water-Drop-Shaped Pressure Hulls with Various Shape Indices Under Hydrostatic External Pressure

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China Ocean Engineering 2024年第1期38卷 1-17页

作者： DING xiao-de ZHANG Jian WANG Fang JIAO hui-feng WANG Ming-lu School of Mechanical Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China Shanghai Engineering Research Center of Marine Renewable Energy College of Engineering Science and Technol-ogyShanghai Ocean UniversityShanghai 201306China China Ship Scientific Research Center Wuxi 214082China

The water-drop-shaped pressure hull has a good streamline,which has good application prospect in the underwater ***,this study conducted analytical,experimental and numerical investigation of the buckling properties of water-drop-shaped pressure hulls under hydrostatic pressure.A water-drop experiment was conducted to design water-drop-shaped pressure hulls with various shape *** critical loads for the water-drop-shaped pressure hulls were resolved by using Mushtari’s *** numerical simulations including linear buckling analysis and nonlinear buckling analysis including eigenmode imperfections were *** results indicated that the critical loads resolved by Mushtari's formula were in good agreement with the linear buckling loads from the numerical *** formula can be extended to estimate the buckling capacity of water-drop-shaped pressure *** addition,three groups of pressure hulls were fabricated by using stereolithography,a rapid prototyping ***,three groups of the pressure hulls were subjected to ultrasonic measurements,optical scanning,hydrostatic testing and numerical *** experimental results were consistent with the numerical *** results indicate that the sharp end of the water-drop-shaped pressure hulls exhibited instability compared with the blunt *** paper provides a new solution to the limitations of experimental studies on the water-drop-shaped pressure hulls as well as a new configuration and evaluation method for underwater observatories.

关键词： buckling pressure hull water drop underwater observatory

Quantum squeezing induced nonreciprocal phonon laser

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Science China(Physics,Mechanics & Astronomy) 2024年第6期67卷 20-30页

作者： Tian-Xiang lu Yan Wang Keyu Xia Xing xiao Le-Man Kuang hui Jing College of Physics and Electronic Information Gannan Normal UniversityGanzhou 341000China Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education Department of Physics and Synergetic Innovation Center for Quantum Effects and ApplicationsHunan Normal UniversityChangsha 410081China Academy for Quantum Science and Technology Zhengzhou University of Light IndustryZhengzhou 450002China College of Engineering and Applied Sciences National Laboratory of Solid State Microstructuresand Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210023China

Phonon lasers or coherent amplifications of mechanical oscillations are powerful tools for fundamental studies on coherent acoustics and hold potential for diverse applications,ranging from ultrasensitive force sensing to phononic information ***,we propose the use of an optomechanical resonator coupled to a nonlinear optical resonator for directional phonon *** find that by pumping the nonlinear optical resonator,directional optical squeezing can occur along the pump *** a result,we can achieve the directional mechanical gain using directional optical squeezing,thereby leading to nonreciprocal phonon lasing with a well-tunable directional power *** work proposes a feasible way to build nonreciprocal phonon lasers with various nonlinear optical media,which are important for a wide range of applications,such as directional acoustic amplifiers,invisible sound sensing or imaging,and one-way phononic networks.

关键词： nonreciprocal phonon laser directional quantum squeezing optomechanics

On the Monge–Kantorovich Mass Transfer Problem in Higher Dimensions

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Acta Mathematica Sinica,English Series 2024年第8期40卷 1989-2004页

作者： xiao Jun lu School of Mathematics Southeast UniversityNanjing 210096P.R.China

This paper mainly investigates the approximation of a global maximizer of the Monge–Kantorovich mass transfer problem in higher dimensions through the approach of nonlinear partial differential equations with Dirichlet *** an approximation mechanism,the primal maximization problem can be transformed into a sequence of minimization *** applying the systematic canonical duality theory,one is able to derive a sequence of analytic solutions for the minimization *** the final analysis,the convergence of the sequence to an analytical global maximizer of the primal Monge–Kantorovich problem will be demonstrated.

关键词： Monge-Kantorovich mass transfer singular variational problem canonical duality theory

Phase field modeling of grain stability of nanocrystalline alloys by explicitly incorporating mismatch strain

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Rare Metals 2024年第7期43卷 3370-3382页

作者： Min Zhou Hong-hui Wu Yuan Wu hui Wang Xiong-Jun Liu Sui-He Jiang xiao-Bin Zhang Zhao-Ping lu Beijing Advanced Innovation Center for Materials Genome Engineering State Key Laboratory for Advanced Metals and MaterialsUniversity of Science and Technology BeijingBeijing 100083Cnina Institute for Carbon Neutrality University of Science and TechnologyBeijing 100083China Institute of Materials Intelligent Technology Liaoning Academy of MaterialsShenyang 110004China

Ab st ra ct Nanocrystalline materials exhibit unique properties due to their extremely high grain boundary(GB) ***,this high-density characteristic induces grain coarsening at elevated temperatures,thereby limiting the widespread application of nanocrystalline *** experimental observations revealed that GB segregation and second-phase pinning effectively hinder GB migration,thereby improving the stability of nanocry stalline *** this study,a mouified phase-field model that integrates mismatch strain,solute segregation and precipitation was developed to evaluate the influence of lattice misfit on the thermal stability of nanocrystalline *** simulation results indicated that introducing a suitable mismatch strain can effectively enhance the microstructural stability of nanocrystalline *** synergizing precipitation with an appropriate lattice misfit,the formation of second-phase particles in the bulk grains can be suppressed,thereby facilitating solute segregation/precipitation at the *** concentrated solute segregation and precipitation at the GBs effectively hinders grain migration,thereby preventing grain *** findings provide a new perspective on the design and regulation of nanocrystalline alloys with enhanced thermal stability.

关键词： Phase field model Mismatch strain Second-phase precipitation Grain boundary segregation Nanocrystalline alloys

Decentralized Optimal Control and Stabilization of Interconnected Systems With Asymmetric Information

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IEEE/CAA Journal of Automatica Sinica 2024年第3期11卷 698-707页

作者： Na Wang xiao Liang Hongdan Li xiao lu the College of Electrical Engineering and Automation Shandong University of Science and TechnologyQingdao 266000China the School of Automation and Electrical Engineering Linyi UniversityLinyi 276000China the College of Energy Storage Technology Shandong University of Science and TechnologyQingdao 266000China

The paper addresses the decentralized optimal control and stabilization problems for interconnected systems subject to asymmetric *** with previous work,a closed-loop optimal solution to the control problem and sufficient and necessary conditions for the stabilization problem of the interconnected systems are given for the first *** main challenge lies in three aspects:Firstly,the asymmetric information results in coupling between control and estimation and failure of the separation ***,two extra unknown variables are generated by asymmetric information(different information filtration)when solving forward-backward stochastic difference ***,the existence of additive noise makes the study of mean-square boundedness an *** adopted technique is proving and assuming the linear form of controllers and establishing the equivalence between the two systems with and without additive noise.A dual-motor parallel drive system is presented to demonstrate the validity of the proposed algorithm.

关键词： Asymmetric information decentralized control forwardbackward stochastic difference equations interconnected system stalibization