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Vectorization of line drawing image based on junction analysis

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Science China(Information Sciences) 2015年第7期58卷 99-112页

作者： CHEN JiaZhou lei qi MIAO YongWei PENG QunSheng College of Computer Science Zhejiang University of Technology State Key Laboratory of CAD&CG Zhejiang University

Converting a scanned or shot line drawing image into a vector graph can facilitate further edit and reuse, making it a hot research topic in computer animation and image processing. Besides avoiding noise influence, its main challenge is to preserve the topological structures of the original line drawings, such as line junctions, in the procedure of obtaining a smooth vector graph from a rough line drawing. In this paper, we propose a vectorization method of line drawings based on junction analysis, which retains the original structure unlike done by existing methods. We first combine central line tracking and contour tracking, which allows us to detect the encounter of line junctions when tracing a single path. Then, a junction analysis approach based on intensity polar mapping is proposed to compute the number and orientations of junction ***, we make use of bending degrees of contour paths to compute the smoothness between adjacent branches,which allows us to obtain the topological structures corresponding to the respective ones in the input *** also introduce a correction mechanism for line tracking based on a quadratic surface fitting, which avoids accumulating errors of traditional line tracking and improves the robustness for vectorizing rough line *** demonstrate the validity of our method through comparisons with existing methods, and a large amount of experiments on both professional and amateurish line drawing images.

关键词： vectorization line drawing line tracking junction analysis vector graph

Compensation in PID Control System for Valve Stiction Based on Equivalent-Input-Disturbance Approach 36

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Compensation in PID Control System for Valve Stiction Based ...

Vapor-phase synthesis of N-butylaniline from aniline and 1-butanol over Cu/SiO_2 catalyst

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作者： qi lei Xi lei Min Wu School of Information Science and Engineering Central South University School of Automation China University of Geosciences Hubei key Laboratory of Advanced Control and Intelligent Automation for Complex Systems

ISBN: (纸本)9781538629185

In industrial processes,valve stiction often induces loop oscillations,and limits the control loop *** better control the plant with valve stiction,in this paper,the equivalent-input-disturbance（EID） approach is incorporated into the conventional PID control system to improve the ability of disturbance and nonlinearity *** newly proposed method uses a classic two-parameter stiction model to represent the nonlinearity of valve *** to the EID method,an EID estimator is constructed to estimate the influence of valve stiction on the system *** controller is based on the basic proportional-integral-derivative（PID） *** a simulation example is provided to demonstrate the validity of this method.

关键词： Valve Stiction Equivalent-Input-Disturbance(EID) Proportional-Integral-Derivative(PID) Compensation

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Journal of Natural Gas Chemistry 2008年第1期17卷 110-111页

作者： Xue Dong Jing Liu lei Shi qi Sun Institute of Chemistry for Functionalized Materials Liaoning Normal University Dalian 116029 Liaoning China

The Cu/SiO2 catalyst prepared by incipient wetness method exhibited very high activity and selectivity for the vapor-phase synthesis of N-butylaniline from aniline and 1-butanol. When Cu loading was 0.70 mmol/g-SiO2 and the catalyst precursor was calcined at 500 ℃, 1-butanol conversion reached 99%, and the selectivity of N-butylaniline exceeded 97%.

关键词： Cu/SiO2 catalyst N-butylaniline aniline 1-butanol

Circuit Model with Current Interruption for Hybrid High Voltage DC Circuit Breakers to Achieve Precise Current Experiments

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CSEE Journal of Power and Energy Systems 2022年第4期8卷 1250-1260页

作者： Zhonghao Dongye lei qi Bing Ji Xiaoguang Wei Xiang Cui State Key Laboratory of Altermate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijing 102206China School of Engineering University of LeicesterLE17RH LeicesterU.K State Key Laboratory of Advanced Power Transmission Technology Global Energy Interconection Research Institute Co.Ld.Beijing 102209China

The current interruption test based on an LC resonance circuit for hybrid DC circuit breakers(HVDC CBs)is widely employed to characterize the current interruption capability of *** order to ensure a high-fidelity replica of the fault current in a high voltage application,this paper first proposes an equivalent model of the test circuit,where not only parasitic resistances but also the threshold voltages and on-state resistances of various semiconductor devices are ***,the analytical formula of the test current is derived by including the working principle of the HVDC ***,the parameter extraction method,which combines finite element analysis and measurements by an impedance analyzer,is given in this *** extracted result implies that,in current interruption transients,equivalent resistances of 500 kV CB are as large as 535 mS,which have a significant influence on current ***,the 34 kV/25 kA current interruption test for the 500 kV CB is *** measured results are proved to be consistent with the analytical results obtained from the proposed model,and the relative error is less than 2%.

关键词： Current interruption test high voltage DC circuit breaker

A novel multi-fidelity coupled simulation method for flow systems

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Chinese Journal of Aeronautics 2013年第4期26卷 868-875页

作者： Wang Peng Zheng Yun Zou Zhengping qi lei Zhou Zhixiang National Key Laboratory of Science & Technology on Aero-Engine Aero-thermodynamics School of Energy and Power Engineering Beihang University Aeroengine Numerical Simulation Research Center School of Energy and Power Engineering Beihang University Chinese Aviation Powerplant Research Institute

For the numerical simulation of flow systems with various complex components, the traditional one-dimensional （1D） network method has its comparative advantage in time consuming and the CFD method has its absolute advantage in the detailed flow capturing. The proper coupling of the advantages of different dimensional methods can strike balance well between time cost and accuracy and then significantly decrease the whole design cycle for the flow systems in modern machines. A novel multi-fidelity coupled simulation method with numerical zooming is developed for flow systems. This method focuses on the integration of one-, two-and three-dimensional codes for various components. Coupled iterative process for the different dimensional simulation cycles of sub-systems is performed until the concerned flow variables of the whole system achieve convergence. Numerical zooming is employed to update boundary data of components with different dimen-sionalities. Based on this method, a highly automatic, multi-discipline computing environment with integrated zooming is developed. The numerical results of Y-Junction and the air system of a jet engine are presented to verify the solution method. They indicate that this type of multi-fidelity simulationmethod can greatly improve the prediction capability for the flow systems.

关键词： Complex flow system Coupling Jet engine Multi-fidelity Zooming

PCBP1 modulates the innate immune response by facilitating the binding of cGAS to DNA

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Cellular & Molecular Immunology 2021年第10期18卷 2334-2343页

作者： Chen-Yang Liao Cao-qi lei Hong-Bing Shu Department of Infectious Diseases Frontier Science Center for Immunology and MetabolismMedical Research InstituteZhongnan Hospital of Wuhan UniversityWuhan University430071 WuhanChina

Cyclic GMP-AMP synthase(cGAS)is a key sensor critical for the recognition of DNA in the cytosol and catalyzes the synthesis of the second messenger cyclic GMP-AMP(cGAMP),which binds to the adapter protein MITA(also known as STING,MPYS,and ERIS)to initiate the innate immune *** the binding of DNA to and the activation of cGAS are regulated remains poorly *** a biochemical purification approach,we identified poly(rC)-binding protein 1(PCBP1)as a cGAS-associated ***1 was recruited to cGAS in a viral infection-dependent ***1 directly bound to DNA and enhanced cGAS binding to its ligands,which was important for cGAS ***,PCBP1 deficiency inhibited cytosolic DNA-and DNA virus-triggered transcription of downstream effector *** findings suggest that PCBP1 plays an important role in the cGAS-mediated innate immune response to DNA virus infection by promoting the binding of cGAS to viral DNA.

关键词： cGAS PCBP1 DNA virus Innate Immunity

Analysis for magnetic field disturbance of modular multilevel converter based high voltage direct current(MMC-HVDC)converter valve

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High Voltage 2023年第1期8卷 91-101页

作者： lei qi Muxue Wang Xiangyu Zhang Hong Shen Hongyu Wang Chongqing Jiao State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijingChina

The standardised design and operational reliability enhancement of the flexible DC converter valve are impending with the construction of high shares of renewables and power electronics power system.A power frequency magnetic field calculation model able to obtain the electromagnetic disturbance at the submodule(SM)drive board during normal operation of a flexible DC converter valve is *** of SMs with complex structures in a converter valve tower are simplified by the equivalent to the line current to fulfil calculation accuracy *** addition,a random function is employed to simulate the non-sequential switching process of the *** comparing the calculated results with the measured data obtained from the SM equivalent operation experiment of 2200 V/2150 A,the validity of the calculation model is *** to the final calculations,the influence of non-sequential switching cannot be ignored when recognising the time-domain distribution features of the power frequency magnetic field of the drive ***,engineering design can be guided only by the power frequency magnetic field intensity of the drive board calculated based on SM’s full removal in the valve tower.

关键词： disturbance converter magnetic

Organocatalytic Copolymerization of Mixed Type Monomers

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Chinese Journal of Polymer Science 2017年第5期35卷 581-581,582-601页

作者： qi-lei Song Shuang-yan Hu 赵俊鹏 Guang-zhao Zhang Faculty of Materials Science and Engineering South China University of Technology

Triggered by environmental concerns and the rising demands for metal-free polymers in e.g. bio-related and microelectronic applications, studies on organocatalytic polymerization have been launched and developed unprecedentedly during the last 15 years. A wide range of organic molecules are now available in polymer chemists＇ toolbox to choose from as catalysts for polymerization of （hetero）cyclic and polar vinyl monomers. Apart from the intrinsic merits such as lower toxicity and better solubility compared with （transition） metal catalysts/initiators, organocatalysts have also shown, in many cases, excellence to achieve high polymerization rates and/or good control （selectivity）. In addition, particular natures and catalytic/activating mechanisms of organocatalysts have led to new opportunities for rational design and efficient synthesis of macromolecular architectures, i.e. chain structures, topological structures and functionalities. This mini-review is specially themed on pathways to construct copolymer chain structures by organocatalytic copolymerization of mixed type monomers （comonomers bearing different polymerizing moieties） and will be sectioned by different comonomer combinations, including cyclic monoesters of different sizes, cyclic monoesters and lactides, cyclic esters and cyclic carbonates or epoxides, heterocycles and vinyl monomers.

关键词： Chain structure Copolymer Organocatalytic polymerization

Numerical Investigation of the Influence of Fuel Concentration Gradient on Propane/Oxygen Detonation Propagation

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Journal of Thermal Science 2023年第6期32卷 2336-2350页

作者： SHAO Xiaofeng WU Tianxing MENG qingyang ZHAO Ningbo qi lei ZHENG Hongtao College of Power and Energy Engineering Harbin Engineering UniversityHarbin150001China College of Power and Energy Engineering Northeast Electric Power UniversityJilin132012China

In this paper,one-and two-dimensional numerical simulations are carried out to study the effects of fuel concentration gradients(such as steep,intermediate and shallow)on the detonation wave *** equivalent ratio range of detonation propagation,the quenching mechanism and the change of cell size are discussed in *** simulation results show,as the fuel concentration gradient increases,the detonation wavefront decays faster and decouples into a leading shock and a following flame at equivalence ratios of 0.68,0.64 and 0.62,***,there are two modes of the quenching *** occurs in the steep gradient that the detonation wave fails *** O_(2)in front of the detonation wave passes through the detonation wave and forms some unburned O_(2)*** unburned pockets are affected by the marginal walls and reduce the heat *** other occurs in the intermediate and shallow gradients that more triple points will survive in the flow field,which leads to a difference in the propagation speed of the detonation *** makes the detonation wavefront bent and *** unburned O_(2)pockets are affected by the strong instability near the triple points and show different distribution characteristics compared with the steep gradient,which may be helpful to the detonation *** addition,as the fuel concentration gradient increases,the triple points moving toward the wall gradually disappear while the triple points that move toward the center can continue to survive,which leads to the gradual increase in cell size and irregularity of the cell structure.

关键词： detonation wave fuel concentration gradient triple point numerical simulation