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Geometric modeling of underground ferromagnetic pipelines for magnetic dipole reconstruction-based magnetic anomaly detection

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Petroleum 2020年第2期6卷 189-197页

作者： Dandan Zhao Zhiyong Guo jian Du Zhongxiang liu Wei Xu Gaofei liu School of Mechatronic Engineering Southwest Petroleum UniversityChengdu610500China China Petroleum Pipeline Insptection Technologies Co. LtdLangfang065000China

To aid the magnetic anomaly detection(MAD)of underground ferromagnetic pipelines,this paper proposes a geometric modeling method based on the magnetic dipole reconstruction method(MDRM).First,the numerical modeling of basic pipe components such as straight sections,bends and elbows,and tee joints are discussed and the relevant mathematical formulations for these components are ***,after analyzing the function of MDRM and various element division strategies,the sectional division and blocked division methods are introduced and applied to the appropriate pipeline components to determine the volume and center coordinates of each element,establishing the general models for the three typical pipeline components *** resulting volume and center coordinates of each component are the fundamental parameters for determining the MAD forwarding of underground ferromagnetic pipelines using the ***,based on the combination and transformation of the basic pipeline components considered,the visualized geometric models of typical pipeline layouts including parallel pipelines,pipelines with elbows,and a pipeline with a tee joint are *** results demonstrate the feasibility of the proposed method of geometric modeling for the MDRM,which can be further applied to the finite element modeling of these and other components when analyzing MAD ***,the models with output parameters proposed in this paper establish a foundation for the inversion of MAD.

关键词： Magnetic anomaly detection Magnetic dipole reconstruction Segmentation method Pipeline detection Geometric modeling

Dynamic parametric modeling-based model updating strategy of aeroengine casings

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Chinese Journal of Aeronautics 2021年第12期34卷 145-157页

作者： Chengwei FEI Haotian liu Shaolin li Huan li liqiang AN Cheng LU Department of Aeronautics and Astronautics Fudan UniversityShanghai 200433China School of Energy and Power Engineering Beihang UniversityBeijing 100083China Beijing Key Laboratory of Aero-Engine Structure and Strength Beijing 100083China Department of Mechanical Engineering North China Electric Power UniversityBaoding 071003China

For accurate Finite Element(FE)modeling for the structural dynamics of aeroengine casings,Parametric Modeling-based Model Updating Strategy(PM-MUS)is proposed based on efficient FE parametric modeling and model updating techniques regarding uncorrelated/correlated mode *** structure is parametrically modeled by simplifying initial structural FE model and equivalently simulating mechanical *** modes between FE model and experiment are reasonably handled by adopting an objective function to recognize correct correlated modes *** parametrized FE model is updated to effectively describe structural dynamic characteristics in respect of testing *** model updating technology is firstly validated by the detailed FE model updating of one fixed–fixed beam structure in light of correlated/uncorrelated mode shapes and measured mode *** PM-MUS is applied to the FE parametrized model updating of an aeroengine stator system(casings)which is constructed by the proposed parametric modeling *** revealed in this study,(A)the updated models by the proposed updating strategy and dynamic test data is accurate,and(B)the uncorrelated modes like close modes can be effectively handled and precisely identify the FE model mode associated the corresponding experimental mode,and(C)parametric modeling can enhance the dynamic modeling updating of complex structure in the accuracy of mode *** efforts of this study provide an efficient dynamic model updating strategy(PM-MUS)for aeroengine casings by parametric modeling and experimental test data regarding uncorrelated modes.

关键词： Aeroengine casings Correlated mode pair Model updating Parametric modeling Structural dynamics Uncorrelated modes

Observation of an anti-cyclonic mesoscale eddy in the subtropical northwestern Pacific Ocean from altimetry and Argo profiling floats

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Acta Oceanologica Sinica 2020年第7期39卷 79-90页

作者： Yang Wang Cheng li Qingyu liu School of Marine Science and Technology Northwestern Polytechnical UniversityXi’an 710072China Maritime Environment Construction Office Beijing 100081China Guangdong Key Laboratory of Coastal Ocean Variability and Disaster Prediction College of Ocean and MeteorologyGuangdong Ocean UniversityZhanjiang 524088China Marine Resources Big Data Center of South China Sea Southern Marine Science and Engineering Guangdong Laboratory(Zhanjiang)Zhanjiang 524025China

The comprehensive three-dimensional structures of an anti-cyclonic mesoscale eddy(AE)in the subtropical northwestern Pacific Ocean were investigated by combining the Argo floats profiles with enhanced vertical and temporal sampling and satellite altimetry *** AE originated near the Kuroshio Extension and then propagated westward with mean velocity of 8.9 cm/*** changes and evolutions during the AE’s growing stage(T1)and further growing stage(T2)were revealed through composite *** the composite eddy core,maximum temperature(T)and salinity(S)anomalies were of 1.7(1.9)℃ and 0.04(0.07)psu in T1(T2)period,*** composite T anomalies showed positive in almost whole depth,but the S anomalies exhibited a sandwich-like *** eddy’s intensification and its influence on the intermediate ocean became more significant during its *** trapping depth increased from 400×10^4 Pa to 580×10^4 Pa while it was growing up,which means more water volume,heat and salt content in deeper layers can be *** AE was strongly nonlinear in upper oceans and can yield a typical mean volume transport of 0.17×10^6 m^3/s and a mean heat and salt transport anomaly of 3.6×10^11 W and–2.1×10^3 kg/s during the observation *** Energy analysis showed that eddy potential and kinetic energy increased notably as it propagated westward and the baroclinic instability is the major energy source of the eddy *** variation of the remained Argo float trapped within the eddy indicated significant water advection during the eddy’s propagation.

关键词： mesoscale eddy three-dimensional structure volume transport available heat and salt content anomaly energy analysis

Boundedness and liveness enforcement for labeled Petri nets using transition priority

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Journal of Electronic Science and Technology 2023年第4期21卷 75-90页

作者： Ye-Jia liu Xun-Bo li School of Mechanical and Electrical Engineering University of Electronic Science and Technology of ChinaChengdu611731China

This paper deals with the supervisory control problem of discrete event systems modeled by labeled Petri nets. The system is originally unbounded. First, the solvability of the problem is confirmed. A necessary condition is given and proven for the existence of a feasible priority-based controller based on the notions of liveness and transition invariants. Next, a cyclic behavior graph is constructed, which shows the reachable markings that guarantee the maximum liveness of the system within a given bound vector. Finally, an on-line control strategy is proposed to enforce boundedness and liveness to the given system by appending priority relations to transitions. The dynamic priority relation changes flexibly according to the current state of the system and enforces the system evolving in a bounded and live manner. In addition, numerical examples are studied to verify the validity of the proposed approach that remains the structure of the plant net and is efficient for on-line control.

关键词： Boundedness Control strategy liveness Petri nets Priority Transition invariant

Finite-State Markov Wireless Channel Modeling for Railway Tunnel Environments

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China Communications 2020年第2期17卷 30-39页

作者： Cuiran li ling liu jianli Xie School of Electronic and Information Engineering Lanzhou Jiaotong University

In recent years,high-speed railways(HSRs)have developed rapidly with a high transportation capacity and high comfort level.A tunnel is a complex high-speed rail terrain *** is very important to establish an accurate channel propagation model for a railway tunnel environment to improve the safety of HSR *** this paper,a method for finite-state Markov chain(FSMC)channel modeling with least squares fitting based on non-uniform interval division is ***,a path loss model is obtained according to measured *** communication distance between the transmitter and receiver in the tunnel is non-uniformly divided into several large non-overlapping intervals based on the path loss ***,the Lloyd-Max quantization method is used to determine the threshold of the signal-to-noise ratio(SNR)and the channel state quantization value and obtain the FSMC state transition probability *** experiments show that the proposed wireless channel model has a low mean square error(MSE)and can accurately predict the received signal power in a railway tunnel environment.

关键词： railway tunnel FSMC channel model SNR path loss

Immobilization of PANI on Mesoporous Carbon： Preparation and Supercapacitor Performance

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Transactions of Nanjing University of Aeronautics and Astronautics 2018年第4期35卷 630-638页

作者： li Jinjin liu Yang li Kunyang Bao Shujuan Urban Vocational College of Sichuan Chengdu 610101 P.R. China Institute for Clean Energy & Advanced Materials Faculty of Materials and Energy Southwest UniversityChongqing 400715 P.R. China

Polyaniline(PANI)was effectively immobilized on the surface of ordered mesoporous carbon(OMC)by using Mn_2O_3 as sacrificial *** observed microstructure and morphology indicate that a thin layer of PANI was coated on OMC *** a supercapacitor electrode material,the discharge capacity of the optimized PANI/OMC could reach 467 F/g,which is far higher than that of OMC,PANI and Mn_2O_3/***,PANI/OMC composites with different content of PANI are obtained by adjusting the amount of Mn_2O_3 on OMC and their properties are *** results show that a thin layer of PANI can improve the capacity of PANI/OMC composites effectively and the further increase of PANI reduces the capacity of PANI/OMC *** sacrificial template method presented here is beneficial to coating a layer of polymer on carbon materials,and the content of polymer layer can be controlled by adjusting the amount of Mn_2O_3 in Mn_2O_3/OMC.

关键词： Mn2O3 sacrificial template polyaniline(PANI) supercapacitor

One-shot Face Reenactment with Dense Correspondence Estimation

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Machine Intelligence Research 2024年第5期21卷 941-953页

作者： Yunfan liu Qi li Zhenan Sun School of Artificial Intelligence University of Chinese Academy of SciencesBeijing100049China Center for Research on Intelligent Perception and Computing Institute of AutomationChinese Academy of SciencesBeijing100190China

One-shot face reenactment is a challenging task due to the identity mismatch between source and driving *** existing methods fail to completely eliminate the interference of driving subjects’identity information,which may lead to face shape distortion and undermine the realism of reenactment *** solve this problem,in this paper,we propose using a 3D morphable model(3DMM)for explicit facial semantic decomposition and identity *** of using 3D coefficients alone for reenactment control,we take advantage of the generative ability of 3DMM to render textured face *** proxies contain abundant yet compact geometric and semantic information of human faces,which enables us to compute the face motion field between source and driving images by estimating the dense *** this way,we can approximate reenactment results by warping source images according to the motion field,and a generative adversarial network(GAN)is adopted to further improve the visual quality of warping *** experiments on various datasets demonstrate the advantages of the proposed method over existing state-of-the-art benchmarks in both identity preservation and reenactment fulfillment.

关键词： Generative adversarial networks face image manipulation face image synthesis face reenactment 3D morphable model

A rapid and convenient experimental method of absolutely calibrating transmission of x-ray flat-response filter

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Chinese Physics B 2018年第10期27卷 271-275页

作者： jian Yu li-Fei Hou Jing Wang Wen-Hai Zhang Ming Chen Bao-Chong Zhou Sha-li Xiao Shen-Ye liu Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province College of Optoelectronic EngineeringShenzhen UniversityShenzhen 518060China Research Center of Laser Fusion China Academy of Engineering PhysicsR O.Box 919-986Mianyang 621900China College of Optoelectronic Engineering Chongqing UniversityChongqing 400044China

We develop a rapid and convenient experimental method of absolutely calibrating the transmission of an x-ray flatresponse filter. The calibration experiment is performed on a small laser-target facility, and a set of high resolution holographic flat-field grating spectrometers is used as a discrimination system of the laser-produced x-ray source. Given that the holographic flat-field grating has a relatively large width, the grating is divided into two regions for use in that direction,where one region has the filter added and the other region does not. The filter transmission is determined by dividing the x-ray signal counts detected when the filter is in the line of sight by those detected when the filter is out of the line of *** find that the calibration results of this experiment agree with the calibration results using a synchrotron radiation source,as well as simulation results. Our method is not only highly reliable but also rapid and convenient.

关键词： flat-response filter absolute transmission flat-field grating spectrometer x-ray CCD camera

Effect of in-situ nanoparticles on the mechanical properties and hydrogen embrittlement of high-strength steel

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International Journal of Minerals,Metallurgy and Materials 2021年第4期28卷 644-656页

作者： Rong-jian Shi Zi-dong Wang li-jie Qiao Xiao-lu Pang Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology BeijingBeijing 100083China Corrosion and Protection Center University of Science and Technology BeijingBeijing 100083China School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China

We investigated the critical influence of in-situ nanoparticles on the mechanical properties and hydrogen embrittlement(HE)of high-strength *** results reveal that the mechanical strength and elongation of quenched and tempered steel(919 MPa yield strength,17.11%elongation)are greater than those of hot-rolled steel(690 MPa yield strength,16.81%elongation)due to the strengthening effect of insitu Ti_(3)O_(5)–Nb(C,N)*** addition,the HE susceptibility is substantially mitigated to 55.52%,approximately 30%lower than that of steels without in-situ nanoparticles(84.04%),which we attribute to the heterogeneous nucleation of the Ti_(3)O_5 nanoparticles increasing the density of the *** with hard TiN inclusions,the spherical and soft Al_(2)O_(3)–MnS core–shell inclusions that nucleate on in-situ Al_(2)O_(3) particles could also suppress ***-situ nanoparticles generated by the regional trace-element supply have strong potential for the development of high-strength and hydrogen-resistant steels.

关键词： in-situ nanoparticles hydrogen embrittlement high-strength steel mechanical properties microstructure