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NUMERICAL STUDY OF 3D EXPLOSION BUBBLES ADJACENT TO STRUCTURES

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Journal of Hydrodynamics 2002年第4期14卷 66-72页

作者： li, Wan-ping li, liang-Jun Dept. of Mech. Huazhong Univ. of Sci. and Technol. Wuhan 430074 China

The bejavior of a bubble near a rigid structure was considered by using the local surface fitting method and the jet prediction method. The convergence difficulty caused by the abnormality of the elements was overcome. The flow was numerically simulated by using the boundary-integral method on the assumption that the water was inviscid and incompressible, and the bubble gas obeyed the isentropic rule. The evolution of the bubble was investigated by means of the mixed Euler-Lagrange method, and the Runge-Kutta method. The important behavior of the bubble, such as migration and jetting, was analyzed in several examples. The solution of one period of the explosion bubble was obtained.

关键词： Bubbles (in fluids) Shock waves Structures (built objects)

A systematic review of machine learning modeling processes and applications in ROP prediction in the past decade

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Petroleum Science 2024年第5期21卷 3496-3516页

作者： Qian li Jun-ping li Lan-Lan Xie College of Environment and Civil Engineering Chengdu University of TechnologyChengdu610059SichuanChina State Key Laboratory of Geohazard Prevention and Geoenvironment Protection(Chengdu University of Technology) Chengdu610059SichuanChina Institute of Exploration Technology CAGSChengdu610059SichuanChina

Fossil fuels are undoubtedly important, and drilling technology plays an important role in realizing fossil fuel exploration;therefore, the prediction and evaluation of drilling efficiency is a key research goal in the industry. limited by the unknown geological environment and complex operating procedures, the prediction and evaluation of drilling efficiency were very difficult before the introduction of machine learning algorithms. This review statistically analyses rate of penetration(ROP) prediction models established based on machine learning algorithms;establishes an overall framework including data collection, data preprocessing, model establishment, and accuracy evaluation;and compares the effectiveness of different algorithms in each link of the process. This review also compares the prediction accuracy of different machine learning models and traditional models commonly used in this field and demonstrates that machine learning models are the most effective technical means in current ROP prediction modeling.

关键词： Drilling Rate of penetration(ROP)prediction Machine learning Accuracy evaluation

Bifurcations of limit Cycles from a Quintic Hamiltonian System with a Heteroclinic Cycle

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Acta Mathematica Sinica,English Series 2014年第3期30卷 411-422页

作者： li Qin ZHAO De ping li School of Mathematical Sciences Beijing Normal UniversityLaboratory of Mathematics and Complex SystemsMinistry of Education

In this paper,we consider li′enard systems of the form dx/dt=y,dy/dt=x＋bx3-x5＋ε（α＋βx2＋γx4）y,where b∈R,0〈｜ε｜〈〈1,（α,β,γ）∈D∈R3 and D is *** prove that for ｜b｜〉〉1（b〈0） the least upper bound of the number of isolated zeros of the related Abelian integrals I（h）=∮Γh（α＋βx2＋γx4）ydx is 2（counting the multiplicity） and this upper bound is a sharp one.

关键词： Hyper-elliptic Hamiltonian system Abelian integral period annulus Picard-Fuchs equa-tion

Relativistic Calculations for Be-like Iron

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Communications in Theoretical Physics 2008年第8期50卷 468-472页

作者： YANG Jian-Hui li ping ZHANG Jian-ping li Hui-li Department of Physics Leshan Teachers College Leshan 614004 China Institute of Atomic and Molecular Physics Sichuan University Chengdu 610065 China

Relativistic configuration interaction calculations for the states of 1s^22s^2, 1s^22s3l （l = s,p,d） and 1s^22p31 （l=s,p,d） configurations of iron are carried out using relativistic configuration interaction （RCI） and multi-configuration Dirac-Fock （MCDF） method in the active interaction approach. In the present calculation, a large-scale configuration expansion was used in describing the target states. These results are extensively compared with other available calculative and experimental and observed values, the corresponding present results are in good agreement with experimental and observed values, and some differences are found with other available calculative values. Because more relativistic effects are considered than before, the present results should be more accurate and reliable.

关键词： transition Fe XXIII multi-configuration Dirac-Fock relativistic configuration interaction

Generalized Rectangular Convexity

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Acta Mathematica Sinica,English Series 2023年第9期39卷 1795-1804页

作者： li ping Yuan Tudor Zamfirescu School of Mathematical Sciences Hebei Normal UniversityShijiazhuang050024P.R.China Hebei International Joint Research Center for Mathematics and Interdisciplinary Science Shijiazhuang050024P.R.China Hebei Key Laboratory of Computational Mathematics and Applications Shijiazhuang050024P.R.China Fachbereich Mathematik TU Dortmund44221DortmundGermany Institute of Mathematics“Simion Stoilow” Romanian AcademyBucharestRomania

In this paper we investigate the tr-convexity and the rectangular biconvexity in Euclidean spaces.

关键词： tr-convex thin rectangular convexity rectangular biconvexity

Rainbow Pancyclicity in a Collection of Graphs Under the Dirac-type Condition

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Acta Mathematicae Applicatae Sinica 2024年第2期40卷 269-274页

作者： Lu-yi li ping li Xue-liang li Center for Combinatorics and LPMC Nankai UniversityTianjin 300071China School of Mathematics and Statistics Shaanxi Normal UniversityXi’an 710062China

Let G={Gi:i∈[n]} be a collection of not necessarily distinct n-vertex graphs with the same vertex set V,where G can be seen as an edge-colored(multi)graph and each Gi is the set of edges with color i.A graph F on V is called rainbow if any two edges of F come from different Gis’.We say that G is rainbow pancyclic if there is a rainbow cycle Cℓof lengthℓin G for each integerℓ2[3,n].In 2020,Joos and Kim proved a rainbow version of Dirac’s theorem:Ifδ(Gi)≥2/n for each i∈[n],then there is a rainbow Hamiltonian cycle in *** this paper,under the same condition,we show that G is rainbow pancyclic except that n is even and G consists of n copies of Kn/2,n/*** result supports the famous meta-conjecture posed by Bondy.

关键词： rainbow Hamiltonian cycle rainbow pancyclic meta-conjecture

A novel predict-prevention quality control method of multi-stage manufacturing process towards zero defect manufacturing

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Advances in Manufacturing 2023年第2期11卷 280-294页

作者： li-ping Zhao Bo-Hao li Yi-Yong Yao State Key Laboratory for Manufacturing Systems Engineering Xi'an Jiaotong UniversityXi'an710049People's Republic of China School of Mechanical Engineering Xi'an Jiaotong UniversityXi'an710049People's Republic of China

Zero defection manufacturing (ZDM) is the pursuit of the manufacturing industry. However, there is a lack of the implementation method of ZDM in the multi-stage manufacturing process (MMP). Implementing ZDM and controlling product quality in MMP remains an urgent problem in intelligent manufacturing. A novel predict-prevention quality control method in MMP towards ZDM is proposed, including quality characteristics monitoring, key quality characteristics prediction, and assembly quality optimization. The stability of the quality characteristics is detected by analyzing the distribution of quality characteristics. By considering the correlations between different quality characteristics, a deep supervised long-short term memory (SLSTM) prediction network is built for time series prediction of quality characteristics. A long-short term memory-genetic algorithm (LSTM-GA) network is proposed to optimize the assembly quality. By utilizing the proposed quality control method in MMP, unqualified products can be avoided, and ZDM of MMP is implemented. Extensive empirical evaluations on the MMP of compressors validate the applicability and practicability of the proposed method.

关键词： Zero defection manufacturing(ZDM) Multi-stage manufacturing process(MMP) Moving window Deep supervised long-short term memory(SLSTM)network Assembly quality optimization

Multiconditional machining process quality prediction using deep transfer learning network

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Advances in Manufacturing 2023年第2期11卷 329-341页

作者： Bo-Hao li li-ping Zhao Yi-Yong Yao State Key Laboratory for Manufacturing Systems Engineering Xi'an Jiaotong UniversityXi'an710049People's Republic of China School of Mechanical Engineering Xi'an Jiaotong UniversityXi'an710049People's Republic of China

The quality prediction of machining processes is essential for maintaining process stability and improving component quality. The prediction accuracy of conventional methods relies on a significant amount of process signals under the same operating conditions. However, obtaining sufficient data during the machining process is difficult under most operating conditions, and conventional prediction methods require a certain amount of training data. Herein, a new multiconditional machining quality prediction model based on a deep transfer learning network is proposed. A process quality prediction model is built under multiple operating conditions. A deep convolutional neural network (CNN) is used to investigate the connections between multidimensional process signals and quality under source operating conditions. Three strategies, namely structure transfer, parameter transfer, and weight transfer, are used to transfer the trained CNN network to the target operating conditions. The machining quality prediction model predicts the machining quality of the target operating conditions using limited data. A multiconditional forging process is designed to validate the effectiveness of the proposed method. Compared with other data-driven methods, the proposed deep transfer learning network offers enhanced performance in terms of prediction accuracy under different conditions.

关键词： Multiconditional machining process Intelligent manufacturing Deep transfer learning Quality prediction Process stability

Control-oriented Modeling for Air-breathing Hypersonic Vehicle Using Parameterized Configuration Approach

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Chinese Journal of Aeronautics 2011年第1期24卷 81-89页

作者： li Huifeng liN ping XU Dajun School of Astronautics Beijing University of Aeronautics and Astronautics Beijing 100191 China

This article presents a parameterized configuration modeling approach to develop a 6 degrees of freedom （DOF） rigid-body model for air-breathing hypersonic vehicle （AHV）. The modeling process involves the parameterized configuration design, inviscous hypersonic aerodynamic force calculation and scramjet engine modeling. The parameters are designed for airframe-propulsion integration configuration, the aerodynamic force calculation is based on engineering experimental methods, and the engine model is acquired from gas dynamics and quasi-one dimensional combustor calculations. Multivariate fitting is used to obtain analytical equations for aerodynamic force and thrust. Furthermore, the fitting accuracy is evaluated by relative error （RE）. Trim results show that the model can be applied to the investigation of control method for AHV during the cruise phase. The modeling process integrates several disciplines such as configuration design, aerodynamic calculation, scramjet modeling and control method. Therefore the modeling method makes it possible to conduct AHV aerodynamics/propulsion/control integration design.

关键词： flight dynamics hypersonic AHV model parameterized configuration design aerodynamics/propulsion integration