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Hot Rolled Strip Re-reddening Temperature Changing Law during Ultra-fast Cooling

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Journal of Iron and Steel Research International 2015年第8期22卷 694-702页

作者： Lian-yun JIANG Chun-jiang ZHAO Jian-hui shi Guo YUAN Xue-qiang WANG Qing-xue HUANG State Key Laboratory of Rolling and Automation Northeastern University School of Mechanical Engineering Taiyuan University of Science and Technology Shougang Qian'an Iron and Steel Co. Ltd.

Temperature deviation between surface and the center of hot rolled strip is formed during ultra-fast cooling （UFC）. Surface temperature would rise when temperature deviation goes up to an extent, and strip re-reddening phenomenon will appear. Strip re-reddening affects the stability of strip microstructure, property and temperature control precision. Thus, it is necessary to conduct research on re-reddening temperature changing law to improve strip property and temperature control precision. Strip temperature trends for various strip thicknesses and ultra-fast cooling rates were obtained by numerical calculation method. Re-reddening temperature, temperature deviation between surface and center, and boundary layer position changing law were obtained. By comparison, some conclusions were obtained： UFC re-reddening temperature and laminar cooling （LC） re-reddening temperature were linear to ultra-fast cooling rate respectively. Ultra-fast cooling rate affected UFC re-reddening temperature greatly, but it had little effect on LC re-reddening temperature. Equations which were used to calculate UFC re-reddening temperature, LC re-reddening temperature and maximum temperature deviation were obtained. The position of boundary layer stayed in 1/4 strip thickness.

关键词： ultra-fast cooling laminar cooling cooling rate re-reddening temperature

First-principles study of the co-effect of carbon doping and oxygen vacancies in ZnO photocatalyst

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Chinese Physics B 2021年第2期30卷 419-425页

作者： Jia shi Lei Wang qiang Gu Department of Physics University of Science and Technology BeijingBeijing 100083China

Although tuning band structure of optoelectronic semiconductor-based materials by means of doping single defect is an important approach for potential photocatalysis application,C-doping or oxygen vacancy(Vo)as a single defect in ZnO still has limitations for photocatalytic ***,the influence of co-existence of various defects in ZnO still lacks sufficient ***,we investigate the photocatalytic properties of ZnOx C0.0625(x=0.9375,0.875,0.8125),confirming that the co-effect of various defects has a greater enhancement for photocatalytic activity driven by visible-light than the single defect in *** clarify the underlying mechanism of co-existence of various defects in ZnO,we perform systematically the electronic properties calculations using density functional *** is found that the coeffect of C-doping and Vo in ZnO can achieve a more controllable band gap than doping solely in ***,the impact of the effective masses of ZnO_(x)C_(0.0625)(x=0.9375,0.875,0.8125)is also taken into *** comparison with heavy Vo concentrations,the light Vo concentration(x=0.875)as the optimal component together with C-doping in ZnO,can significantly improve the visible-light absorption and benefit photocatalytic activity.

关键词： first-principles theory electron density of states and band structure of crystalline solids Ⅲ-ⅤandⅡ-Ⅵsemiconductors

Influence of cross correlation step length on the surface stress of thin laser cladding Fe314 alloy coatings

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International Journal of Minerals,Metallurgy and Materials 2012年第6期19卷 549-554页

作者： Bin Liu shi-yun Dong Bin-shi Xu Peng He State Key Laboratory of Advanced Welding and Joining Harbin Institute of Technology Harbin 150001 China National Key Laboratory for Remanufacturing Academy of Armored Forces Engineering Beijing 100072 China

To measure the surface stress of thin laser cladding coatings with Rayleigh waves based on the cross correlation function, this pa- per introduced the influence of cross correlation step length on the stress measurement. Flat-shaped specimens made of laser cladding Fe314 alloy coatings were performed by static tensile tests, and Rayleigh wave signals were collected during the test process with an ultrasonic pulser and receiver instrument combined with two Rayleigh wave transducers. The difference in time of flight between two signals was de- termined based on the cross correlation function. The microstructure was observed by scanning electronic microscopy. The influence of the stress on the propagation velocity of Rayleigh waves and the relationship between the difference in time of flight and tensile stress under dif- ferent cross correlation step lengths were analyzed. The inhomogeneous deformation of the coatings affects the relationship between the dif- ference in time of flight and tensile stress; the stress measurement of the coatings is nearly constant with the increase of cross correlation step length when it attains one cycle.

关键词： iron alloys metal cladding laser cladding surface stress Rayleigh waves

Controlled Fabrication of Uniform Digital Nanorods from Precise Sequence-Defined Amphiphilic Polymers in Aqueous Media

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Chinese Journal of Polymer Science 2023年第5期41卷 768-777,I0010页

作者： qiang-qiang shi Xin Zhou Jie Xu Ning Wang Jia-Lin Zhang Xiang-Long Hu shi-Yong Liu CAS Key Laboratory of Soft Matter Chemistry Department of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefei 230026China School of Biomedical Engineering and Suzhou Institute for Advanced Research University of Science and Technology of ChinaSuzhou 215123China

Compared with spherical micelles,rod/worm-like micelles not only have extended blood circulation duration,but also exhibit favorable cellular uptake behavior,which is promising for next-generation nanomedicine and ***,the controllable fabrication of narrowly dispersed nanorods in aqueous media is still ***,the methodology of thermal annealing was developed for the fabrication of helical nanorods as well as a series of nanorods with different *** thermal annealing process generally consisted of adding a percentage of organic solvent(10%(V/V)or 20%(V/V))to the digital micellar aqueous dispersion,followed by heating at 90℃for 1 h,then cooling naturally to room temperature,and dialyzing against water to remove the organic ***-handed helical nanorods were afforded by the treatment of 45 nm digital micelles in the presence of 10%(V/V)dioxane,while left-handed helical nanorods were obtained in the presence of 20%(V/V)***,the controlled growth of rod-like digital micelles was achieved after thermal annealing in the presence of different types of organic solvents,and the length of the annealed nanorods was correlated with the types of organic ***,no matter the size of initial digital micelles,they all exhibited similar trend of rod growth in the presence of a certain amount of organic solvent,allowing for controllable formulation of narrowly dispersed *** addition,supramolecular self-assembly by amphiphilic dendritic oligourethane readily fabricated diverse uniform nanorods in aqueous ***,this work provided an attractive methodology to fabricate uniform digital nanorods.

关键词： Sequence-defined amphiphilic polymers Digital nanorods Thermal annealing Dendritic oligourethane Self-assembly

Effect of infusion pressure during cataract surgery on ganglion cells measured using isolated-check visual evoked potential

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International Journal of Ophthalmology(English edition) 2018年第1期11卷 58-65页

作者： Tong Ding Dan-Na shi Xiang Fan Mi-yun Zheng Wei Wang Wei-qiang Qiu Peking University Third Hospital Eye Center Beijing 100191China

AIM： To detect the relationship between infusion pressure and postoperative ganglion cells ***： This prospective observational cohort study included sixty-one eyes that underwent uncomplicated cataract surgery. Patients were divided into two groups according to infusion time（IT） recorded using surgery equipment [Group A： IT〉IT_（mean）（27 eyes）; Group B： IT

关键词： isolated-check visual evoked potential optical coherence tomography ganglion cell inner plexiform layer cataract extraction

Inductive Rings and Systems of Diophantine Equations

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Acta Mathematica Sinica,English Series 2006年第5期22卷 1549-1556页

作者： Rong Fang BIE shi qiang WANG College of Information Science Beijing Normal University Beijing 100875 P. R. China School of Mathematical Sciences Beijing Normal University Beijing 100875 P. R. China

In this paper, by using model-theoretic methods, it is shown that some systems of unsolved cubic diophantine equations in number theory can have solutions in certain inductive extension rings of the ring I of rational integers. These inductive rings are not fields, and every element of them is a sum of 4 cubes and a sum of 3 squares. Also some of them satisfy the Goldbach conjecture and some others don＇t.

关键词： Inductive rings Systems of unsolved cubic diophantine equations Model theory

Two New Fossil Lacewing Species from the Middle Jurassic of Inner Mongolia,China(Neuroptera:Grammolingiidae)

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Acta Geologica Sinica(English Edition) 2011年第2期85卷 482-489页

作者： shi Chaofan YANG qiang REN Dong College of Life Science Capital Normal University Beijing 100048 China

Two new species of lacewings are described and illustrated from the Jiulongshan Formation （Middle Jurassic） of Inner Mongolia, China： Leptolingia calonervis sp. nov. and Litholingia ptesa ***. （Grammolingiidae）. The species can be distinguished by the following features： the outermost branch of MP2 on the hind wing did not reach the margin of wing in Leptolingia calonervis sp. nov.;the second branch of Rs forked deeply while other branches of Rs forked much later in Litholingia ptesa sp. nov..

关键词： Neuroptera Grammolingiidae new species Jiulongshan Formation China

Deformation Behavior of Zr_(65)Cu_(17.5)Ni_(10)Al_(7.5)in Superplastic Forming with Silicon Mould: Simulation and Application

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Journal of Wuhan University of Technology(Materials Science) 2014年第2期29卷 250-255页

作者：杨璠 shi Tielin YU qiang 廖广兰 State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and Technology

We investigated the deformation behaviors of Zr_65Cu_17.5Ni_10Al_7.5 in superplastic forming in silicon mould via numerical modeling and experiments. The data needed for the constitutive formulation were obtained from compressive tests to establish a material library for finite-element simulation using a DEFORM 3D software. A constant speed forming process of a micro gear was modeled where the loading force, feature size and amount of deformation in the micro gear in silicon mould were analyzed in detail for the optimal requirements of micro gear forming and the protection of silicon mould. Guided by the modeling parameters, an amorphous metal micro gear was successfully obtained by our home-made superplastic forming system with the optimized parameters （temperature of 683 K, top speed of 0.003 mm/s until the load force reaching limiting value at 1960 N, and a gradually decelerating process for holding the force to the end）. Our work gives a good example for optimization of superplastic forming and fabrication of BMGs in microparts.

关键词： bulk metallic glass deformation finite-element simulation superplastic forming silicon mould

Unique Parameters Selection Strategy of Linear Canonical Wigner Distribution via Multiobjective Optimization Modeling

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Chinese Journal of Electronics 2023年第3期32卷 453-464页

作者： shi Xiya WU Anyang SUN yun qiang Shengzhou JIANG Xian HAN Puyu CHEN yunjie ZHANG Zhichao School of Mathematics and Statistics Nanjing University of Information Science and Technology Faculty of Information Technology Macau University of Science and Technology

There are many kinds of linear canonical transform(LCT)-based Wigner distributions(WDs),which are very effective in detecting noisy linear frequency-modulated(LFM) signals. Among WDs in LCT domains, the instantaneous cross-correlation function type of Wigner distribution(ICFWD) attracts much attention from scholars, because it achieves not only low computational complexity but also good detection ***, the existing LCT free parameters selection strategy, namely a solution of the expectation-based output signal-to-noise ratio(SNR) optimization model, is not unique. In this paper, by introducing the variance-based output SNR optimization model, a multiobjective optimization model is established. Then the existence and uniqueness of the optimal parameters of ICFWD are investigated. The solution of the multiobjective optimization model with respect to one-component LFM signal added with zero-mean stationary circular Gaussian noise is derived. A comparison of the unique parameters selection strategy and the previous one is carried out. The theoretical results are also verified by numerical simulations.

关键词： Computational modeling Gaussian noise Noise reduction Transforms Signal processing Numerical simulation Numerical models