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Dynamic Recrystallization Behavior of Microalloyed Forged Steel

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Journal of Iron and Steel Research International 2008年第3期15卷 78-81,91页

作者： WANG Jin CHEN jun ZHAO Zhen ruan Xue-yu National Die and Mold CAD Engineering Research Center Shanghai Jiao Tong University Shanghai 200030 China

The dynamic recrystallization behavior of microalloyed forged steel was investigated with a compression test in the temperature range of 1 223-1 473 K and a strain rate of 0. 01-5 s^-1. Activation energy was calculated to be 305.9 kJ/mol by regression analysis. Modeling equations were developed to represent the dynamic recrystallization volume fraction and grain size. Parameters of the modeling equations were determined as a function of the Zener-Hollomon parameter. The developed modeling equation will be combined with finite element modeling to predict microstructural change during the hot forging processing.

关键词： microalloyed forged steel dynamic recrystallization flow stress

Geodesic metrics on fractals and applications to heat kernel estimates

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Science China Mathematics 2023年第5期66卷 907-934页

作者： Qingsong Gu Ka-Sing Lau Hua Qiu Huo-jun ruan Department of Mathematics Nanjing UniversityNanjing 210093China Department of Mathematics The Chinese University of Hong KongHong KongChina Department of Mathematics University of PittsburghPittsburghPA 15217USA School of Mathematical Sciences Zhejiang UniversityHangzhou 310027China

It is well known that for a Brownian motion, if we change the medium to be inhomogeneous by a measure μ, then the new motion(the time-changed process) will diffuse according to a different metric D(·, ·).In 2009, Kigami initiated a general scheme to construct such metrics through some self-similar weight functions g on the symbolic space. In order to provide concrete models to Kigami’s theoretical construction, in this paper,we give a thorough study of his metric on two classes of fractals of primary importance: the nested fractals and the generalized Sierpinski carpets;we further assume that the weight functions g := ga are generated by“symmetric” weights a. Let M be the domain of a such that Dgadefines a metric, and let S be the boundary of M. One of our main results is that the metrics from ga satisfy the metric chain condition if and only if a ∈ *** determine M and S, we provide a recursive weight transfer construction on the nested fractals, and a basic symmetric argument on the Sierpinski carpet. As an application, we use the metric chain condition to obtain the lower estimate of the sub-Gaussian heat kernel. This together with the upper estimate obtained by Kigami allows us to have a concrete class of metrics for the time change, and the two-sided sub-Gaussian heat kernel estimate on the fundamental fractals.

关键词： Brownian motion heat kernel metric chain condition nested fractal quasisymmetry resistance metric Sierpinski carpet weight function

Sliding of self-similar sets

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Science China Mathematics 2007年第3期50卷 351-360页

作者： Li-feng XI Huo-jun ruan Qiu-li GUO Institute of Mathematics Zhejiang Wanli UniversityNingbo 315100China Department of Mathematics Zhejiang UniversityHangzhou 310027China

This paper deals with the Lipschitz equivalence of slidings of self-similar sets by graph-directed construction and martingale theory.

关键词： fractal self-similar set Lipschitz equivalence 28A80

Programmable complex pumping field induced color-on-demand random lasing in fiber-integrated microbelts for speckle free imaging

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Science China(Information Sciences) 2023年第12期66卷 251-260页

作者： Xiaoyu SHI Kaiyue SHEN Yaoxing BIAN Wanting SONG jun ruan Zhaona WANG Tianrui ZHAI College of Physics and Optoelectronics Faculty of ScienceBeijing University of Technology Applied Optics Beijing Area Major Laboratory Department of PhysicsBeijing Normal University

Miniaturized lasers with on-demand color emission have immense potential in the development of integrated imaging sources. Random lasers(RLs) with cavity-free structures and low spatial coherence are promising candidates for multicolor imaging sources. However, the wide tuning range and high tuning accuracy of continuous and reversible random lasing color with a defined emissive direction remain challenging. Here, random lasing with on-demand color emission and defined emissive direction is realized in fiber-integrated microbelts through programmable pumping. Individual RL microbelts as RL units doped with blue(B)-, green(G)-, and red(R)-emissive dyes and titanium dioxide nanoparticles are assembled on an optical fiber, resulting in high-performance B/G/R lasing. The optical fiber functions as a waveguide that guides the multicolor RL to ensure a defined directional emission. By manipulating the combination of the B/G/R RL units on the waveguide, distinctive lasing colors covering the entire visible spectrum are obtained, including white-colored random lasing. To realize dynamically controllable lasing for on-demand color emission, a pumping strategy with programmable excitation is proposed by shaping the pump beams into different beam arrays for precisely pumping the RL unit combination. We envision that fiber-integrated RL sources can be implemented in various imaging applications, such as biomedical diagnosis, multiplexed communication, and optical sensing.

关键词： random laser multi-color pump control fiber-integrated directional emission

RGB WGM lasing woven in fiber braiding cavity

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Science China(Information Sciences) 2022年第8期65卷 247-253页

作者： Kun GE Zhiyang XU Dan GUO Ben NIU jun ruan Libin CUI Tianrui ZHAI College of Physics and Optoelectronics Faculty of ScienceBeijing University of Technology

It is critical to realize woven and wearable red-green-blue(RGB) whispering gallery mode(WGM)lasing that is tunable and flexible in the fiber braiding cavity. However, it is still a challenge to achieve tunable full-color lasing with the large color gamut by a facile approach. Here, we design the braiding cavity to realize RGB WGM lasing with high performance. The braiding cavity consists of three optical fibers coated with dye-doped polymer. Each fiber therein serves as a resonant cavity to support multiple lasing modes. There is no interference owing to the air gap between them; therefore, we can achieve full-color WGM lasing. The lasing emission in our fiber braiding cavity covers a color gamut of 86.7% larger than standard RGB *** work may provide a platform for potential applications in white laser and integrated optoelectronic devices.

关键词： RGB whispering gallery mode (WGM) lasing fiber braidingcavity full-color gamut

Studies of flow field characteristics during the impact of a gaseous jet on liquid–water column

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Chinese Physics B 2019年第6期28卷 293-301页

作者： Jian Wang Wen-jun ruan Hao Wang Li-Li Zhang School of Energy and Power Engineering Nanjing University of Science and TechnologyNanjing 210094China Harbin Jian Cheng Bloc Limited Company Harbin 150030China

Both experimental and numerical studies were presented on the flow field characteristics in the process of gaseous jet impinging on liquid–water column. The effects of the impinging process on the working performance of rocket engine were also analyzed. The experimental results showed that the liquid–water had better flame and smoke dissipation effect in the process of gaseous jet impinging on liquid–water column. However, the interaction between the gaseous jet and the liquid–water column resulted in two pressure oscillations with large amplitude appearing in the combustion chamber of the rocket engine with instantaneous pressure increased by 17.73% and 17.93%, respectively. To analyze the phenomena, a new computational method was proposed by coupling the governing equations of the MIXTURE model with the phase change equations of water and the combustion equation of propellant. Numerical simulations were carried out on the generation of gas, the accelerate gas flow, and the mutual interaction between gaseous jet and liquid–water *** simulations showed that a cavity would be formed in the liquid–water column when gaseous jet impinged on the liquid–water column. The development speed of the cavity increased obviously after each pressure oscillation. In the initial stage of impingement, the gaseous jet was blocked due to the inertia effect of high-density water, and a large amount of gas gathered in the area between the nozzle throat and the gas–liquid interface. The shock wave was formed in the nozzle expansion section. Under the dual action of the reverse pressure wave and the continuously ejected high-temperature gas upstream, the shock wave moved repeatedly in the nozzle expansion section, which led to the flow of gas in the combustion chamber being blocked, released, re-blocked, and re-released. This was also the main reason for the pressure oscillations in the combustion chamber.

关键词： gaseous jet liquid–water column pressure oscillations shock wave

Clozapine is strongly associated with the risk of pneumonia and inflammation

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General Psychiatry 2020年第2期33卷 66-72页

作者： Jose de Leon Can-jun ruan Helene Verdoux Chuanyue Wang University of Kentucky Mental Health Research Center Eastern State HospitalLexingtonKentuckyUSA Beijing Key Laboratory of Mental Disorders Beijing Anding HospitalBeijingChina Inserm Bordeaux Population Health Research CenterUniversity of Bordeaux Faculty of Medical SciencesBordeauxAquitaineFrance

Clinicians need to remember that(1)systemic inflammations can increase clozapine level;(2)clozapine,by itself,can cause inflammation,particularly during titration that is too rapid for that patient;(3)clozapine may increase the risk of infection;and(4)more specifically,clozapine may be particularly strongly associated with the risk of *** appears to be associated with high mortality in clozapine patients around the *** who are alert to the risk of pneumonia in clozapine patients may significantly decrease mortality in clozapine *** is no data on COVID-19 infections in clozapine patients,but based on what we know about clozapine pharmacology,we can hypothesise that clozapine,possibly by impairing immunological mechanisms,may increase the risk of pneumonia in infected *** importantly,once fever and/or pneumonia develops,the clozapine dose should be cut in half to decrease the risk of clozapine *** there is any doubt that in spite of halving the dose there are still signs of clozapine intoxication,completely stopping clozapine may be *** the signs of inflammation and fever have disappeared,the clozapine dose can be increased to the prior dosage level.

关键词： inflammation pneumonia mortality

Aerodynamic Characteristics of Projectile with Exotic Wraparound Wings Configuration

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Journal of Harbin Institute of Technology(New Series) 2014年第3期21卷 30-37页

作者： Fu Zhang Wen-jun ruan Hao Wang Chen-Guang Zhu Meng-Hua Zhang School of Energy and Power Engineering Nanjing University of Science and Technology

A projectile with exotic wraparound wings( WAW) configuration is designed to improve the finstabilized projectile shooting quality. Two fin-stabilized projectiles with the same body with and without exotic WAW configuration are simulated numerically by applying the Roe scheme. The shear-stress transport turbulence models and the lower-upper symmetric Gauss-Seidel implicit method are used to solve 3D Reynoldsaveraged Navier—Stokes equations. The differences in aerodynamic coefficients and aerodynamic characteristics of the projectiles when the Mach number varies from 0. 35 to 0. 95 are obtained,and the cause of these differences is analyzed. The calculation results indicate that the lift-to-drag ratio of the projectile significantly increases,the rolling moment decreases,and the position of the pressure center of the projectile shows relatively small changes when the exotic WAW configuration is used. Therefore,this projectile can obviously reduce rolling effect,enlarge range and improve flying stability.

关键词： exotic WAW configuration aerodynamic characteristic hybrid structure-unstructured grid overlapping grid

Zircon U-Pb age of the Shacun gabbro body, Yuexi, Dabie orogen and its geological implications

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Chinese Science Bulletin 2000年第1期45卷 74-79页

作者： GE Ningjie HOU Zhenhui LI Huimin CHEN Jiangfeng LIU Bin ruan jun QIN Liping Department of Earth and Space Sciences University of Science and Technology of ChinaHefei 230026China Tianjing Institute of Geology and Mineral Resources CAGSTianjin 300170China Economic Plan Committee of Anhui Province Hefei 230001China

The single grain zircon U-Pb age of the Shacun mafic-ultramafic intrusion, Yuexi, North Dabie is (128.1 ±2.0) *** date indicates that the intrusion was implaced at Yanshanian when most Mesozoic granitoids were intruded. It was not the syn-collisional intrusion related to the subduction of the Yangtze Block and ultrahigh-pressure metamorphism at Indosinian.

关键词： gabbro single grain zircon U-Pb chronology Dabie Mountains.