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Chinese Journal of Mechanical Engineering 2021年第6期34卷 224-239页

作者： Sai Guo Guanhui Ren bi Zhang Department of Mechanical and Energy Engineering Southern University of Science and TechnologyShenzhenGuangdongChina State Key Laboratory of Ultra-precision Machining Technology Department of Industrial and Systems EngineeringThe Hong Kong Polytechnic UniversityKowloonHong KongChina

New materials and manufacturing technologies require applicable non-destructive techniques for quality assurance so as to achieve better *** study comprehensively investigated the effect of influencing factors includ-ing excitation frequency,lift-off distance,defect depth and size,residual heat,and surface roughness on the defect EC signals of an Inconel 738LC alloy produced by selective laser melting(SLM).The experimental investigations recorded the impedance amplitude and phase angle of EC signals for each defect to explore the feasibility of detecting sub-surface defects by merely analyzing these two key ***,this study revealed preliminary qualitative and roughly quantitative relationships between influencing factors and corresponding EC signals,which provided a prac-tical reference on how to quantitively inspect subsurface defects using eddy current testing(ECT)on SLMed parts,and also made solid progress toward on-line ECT in additive/subtractive hybrid manufacturing(ASHM)for fabricating SLMed parts with enhanced quality and better performance.

关键词： Eddy current testing Subsurface defect Additive/subtractive hybrid manufacturing Selective laser melting Inconel 738LC alloy

SOLVING RESOURCE-CONSTRAINED PROJECT SCHEDULING PROBLEMS WITH bi-CRITERIA HEURISTIC SEARCH TECHNIQUES

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Systems Science and Systems Engineering 2003年第2期12卷 190-203页

作者： M Kamrul AHSAN De-bi TSAO Department of Industrial Engineering and Management Tokyo Institute of Technology 2-12-1 O-okayamaMeguro-kuTokyo 152-8552JapanDepartment of Industrial Engineering and Management Tokyo Institute of Technology2-12-1 O-okayamaMeguro-kuTokyo 152-8552Japan

In this paper we formulate a bi-criteria search strategy of a heuristic learning algorithm for solving multiple resource-constrained project scheduling problems. The heuristic solves problems in two phases. In the pre-processing phase, the algorithm estimates distance between a state and the goal state and measures complexity of problem instances. In the search phase, the algorithm uses estimates of the pre-processing phase to further estimate distances to the goal state. The search continues in a stepwise generation of a series of intermediate states through search path evaluation process with backtracking. Developments of intermediate states are exclusively based on a bi-criteria new state selection technique where we consider resource utilization and duration estimate to the goal state. We also propose a variable weighting technique based on initial problem complexity measures. Introducing this technique allows the algorithm to efficiently solve complex project scheduling problems. A numerical example illustrates the algorithm and performance is evaluated by extensive experimentation with various problem parameters. Computational results indicate significance of the algorithm in terms of solution quality and computational performance.

关键词： Resource-constrained project scheduling search algorithm heuristics state-space representation

Fault Feature Extraction of Diesel Engine Based on bispectrum Image Fractal Dimension

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Chinese Journal of Mechanical Engineering 2018年第2期31卷 216-226页

作者： Jian Zhang Chang-Wen Liu Feng-Rong bi Xiao-Bo bi Xiao Yang State Key Laboratory of Engines Tianjin University

Fault feature extraction has a positive effect on accurate diagnosis of diesel engine. Currently, studies of fault feature extraction have focused on the time domain or the frequency domain of signals. However, early fault signals are mostly weak energy signals, and time domain or frequency domain features will be overwhelmed by strong back?ground noise. In order consistent features to be extracted that accurately represent the state of the engine, bispectrum estimation is used to analyze the nonlinearity, non?Gaussianity and quadratic phase coupling(QPC) information of the engine vibration signals under different conditions. Digital image processing and fractal theory is used to extract the fractal features of the bispectrum pictures. The outcomes demonstrate that the diesel engine vibration signal bispectrum under different working conditions shows an obvious differences and the most complicated bispectrum is in the normal state. The fractal dimension of various invalid signs is novel and diverse fractal parameters were utilized to separate and characterize them. The value of the fractal dimension is consistent with the non?Gaussian intensity of the signal, so it can be used as an eigenvalue of fault diagnosis, and also be used as a non?Gaussian signal strength indicator. Consequently, a symptomatic approach in view of the hypothetical outcome is inferred and checked by the examination of vibration signals from the diesel motor. The proposed research provides the basis for on?line monitoring and diagnosis of valve train faults.

关键词： Engine fault diagnosis bispectrum image processing Fractal Signal processing

Data-driven intelligent modeling framework for the steam cracking process

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Chinese Journal of Chemical Engineering 2023年第9期61卷 237-247页

作者： Qiming Zhao Kexin bi Tong Qiu Department of Chemical Engineering Tsinghua UniversityBeijing 100084China Beijing Key Laboratory of Industrial big Data Systems and Applications Tsinghua UniversityBeijing 100084China School of Chemical Engineering Sichuan UniversitySichuan 610065China Department of bioprocess Engineering Institute of BiotechnologyTechnische Universität BerlinBerlin 10623Germany

Steam cracking is the dominant technology for producing light olefins,which are believed to be the foundation of the chemical *** models of the cracking process can boost production efficiency and profit *** advancements in machine learning research have recently enabled data-driven solutions to usher in a new era of process ***,its practical application to steam cracking is still hindered by the trade-off between prediction accuracy and computational *** research presents a framework for data-driven intelligent modeling of the steam cracking *** data preparation and feature engineering techniques provide computational-ready datasets for the framework,and feedstock similarities are exploited using k-means *** propose LArge-Residuals-Deletion Multivariate Adaptive Regression Spline(LARD-MARS),a modeling approach that explicitly generates output formulas and eliminates potentially outlying *** framework is validated further by the presentation of clustering results,the explanation of variable importance,and the testing and comparison of model performance.

关键词： Mathematical modeling Data-driven modeling Process systems Steam cracking Clustering Multivariate adaptive regression spline

Linear Arboricity of Outer-1-Planar Graphs

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Journal of the Operations Research Society of China 2021年第1期9卷 181-193页

作者： Xin Zhang bi Li School of Mathematics and Statistics Xidian UniversityXi’an 710071China

A graph is outer-1-planar if it can be drawn in the plane so that all vertices are on the outer face and each edge is crossed at most *** et al.(Edge covering pseudo-outerplanar graphs with forests,Discrete Math 312:2788-2799,2012;MR2945171)proved that the linear arboricity of every outer-1-planar graph with maximum degree△is exactly[△/2] provided that△=3or△≥5 and claimed that there are outer-1-planar graphs with maximum degree △=4 and linear arboricity[[(O+1)/2]=*** is shown in this paper that the linear arboricity of every outer-1-planar graph with maximum degree 4 is exactly 2 provided that it admits an outer-1-planar drawing with crossing distance at least 1 and crossing width at least 2,and moreover,none of the above constraints on the crossing distance and Crossing width can be removed..Besides,a polynomial-time algorithm for constructing a path-2-coloring(i.e.,an edge 2-coloring such that each color class induces a linear forest,a disjoint union of paths)of such an outer-1-planar drawing is given.

关键词： Outer-1-planar graph Crossing Linear arboricity Polynomial-time algorithm

Calculating the Wave Force on Partially Immersed Large-Scale Horizontal Cylinders

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China Ocean Engineering 2021年第2期35卷 291-300页

作者： LIU bi-jin FU Dan-juan School of Civil Engineering and Architecture Xiamen University of TechnologyXiamen 361024China

Large-scale interceptors constitute the main structure of offshore self-driven floating marine litter collection devices,and the structural stability of such interceptors under the action of waves directly influences the overall safety of the *** the ratio of the diameter of a horizontal cylinder in such interceptors to the incident wavelength is larger than 0.25,the wave force can be calculated by using the diffraction theory,by considering the problem as that of the interaction between the waves and a partially immersed large-scale horizontal *** this study,an analytical approach to calculate the wave force on a partially immersed large-scale horizontal cylinder was formulated by using the stepwise approximation *** model tests were conducted to investigate the effects of different factors(wave height,period,and immersion depth)on the wave force on a large-scale horizontal cylinder under conditions involving short-period *** results show that both horizontal and vertical wave forces on the cylinder increase as the wave height(immersion depth)increases in most *** vertical wave force decreases with the decrease of the *** the horizontal wave force,it increases with the decrease of the period when the wavelength is larger than the diameter of the cylinder and decreases with the decrease of the period when the wavelength is smaller than the diameter of the cylinder.

关键词： wave force large-scale horizontal cylinder diffraction theory partial immersion stepwise approximation method

Complex bursting patterns in Van der Pol system with two slowly changing external forcings

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Science China(Technological Sciences) 2012年第3期55卷 702-708页

作者： HAN XiuJing bi QinSheng Faculty of Civil Engineering and Mechanics Jiangsu UniversityZhenjiang 212013China

This paper investigates the generation of complex bursting patterns in Van der Pol system with two slowly changing external forcings. Complex bursting patterns, including complex periodic bursting and chaotic bursting, are presented for the cases when the two frequencies are commensurate and incommensurate. These complex bursting patterns are novel and have not been reported in previous work. Based on the fast-slow dynamics, the evolution processes of the slow forcing are presented to reveal the dynamical mechanisms undedying the appearance of these complex bursting patterns. With the change of ampli- tudes and frequencies, the slow forcing may visit the spiking and rest areas in different ways, which leads to the generation of different complex bursting patterns.

关键词： Van der Pol system two external forcings complex periodic bursting patterns chaotic bursting

Study on the Propagation and Focusing Mechanism of Long Waves over A Submerged Atoll

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China Ocean Engineering 2023年第2期37卷 204-217页

作者： FU Dan-juan LIU bi-jin ZHENG Jin-hai WANG Gang CHEN bi-qin School of Civil Engineering and Architecture Xiamen University of TechnologyXiamen 361024China Hainan Institute Zhejiang UniversitySanya 572025China Key Laboratory of Coastal Disaster and Protection Ministry of EducationHohai UniversityNanjing 210098China Fujian Polytechnic of Information Technology Fuzhou 350003China

An analytical solution for long waves propagating over a submerged atoll is established. The atolls involved in this study are annular coral reefs with large lagoons in the middle, and the expression of the cross section is a trinomial function of the radial distance, i.e., h=ar(2s)-br~s+h_0, where s is the positive rational number. This analytical solution extends the theory by Wang et al.(2018) as s is no longer limited to s=2/m, where m is the positive integer. In addition, by adjusting the terrain parameters properly, the analytic solution can be degenerated to describe the wave propagation over topography with a hump or pit. According to the relationship between wave rays and wave energy, the distribution characteristics and formation mechanism of energy over the topography are expounded. When the lagoon is non-existent, all wave rays converge at the x-axis, which results in an abrupt amplification of the wave amplitude around the convergence point. When a lagoon is mounted on the top of the atoll, the rays are scattered due to the refraction of the lagoon, and only some rays converge at the symmetrical axis and the ridges on both sides,which results in the amplification of wave amplitudes in these areas.

关键词： long waves analytic solution wave scattering submerged atoll wave propagation

CD226:a potent driver of antitumor immunity that needs to be maintained

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Cellular & Molecular Immunology 2022年第9期19卷 969-970页

作者： Jiacheng bi CAS Key Laboratory of Quantitative Engineering biology Shenzhen Institute of Synthetic BiologyShenzhen Institutes of Advanced TechnologyChinese Academy of SciencesShenzhenChina

Inhibitory receptors expressed on the immune cell surface have emerged as checkpoint molecules that could be therapeutically targeted for tumor ***,antitumor immunity mediated by checkpoint blockade depends on optimal recognition of tumor cells through the activation of receptors on antitumor effector immune cells,such as CD8^(+)T cells and NK ***,sufficient and maintained expression levels of activating receptors on these effector immune cells are essential for antitumor immunity and checkpoint blockade immunotherapy.

关键词： immunity maintained immunotherapy

Study and design of cladding power stripper for high power fiber laser systems

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High Power Laser Science and Engineering 2016年第3期4卷 71-73页

作者： Haixia An Xiaogang Liu Zhiyue bi Institute of Systems Engineering CAEP

Heat handling has been a significant problem of the high power fiber laser systems as the output power increases *** power stripper(CPS) which is used to deal with the unwanted optical power and light is required for higher cooling ability. So the methods of stripping the unwanted light attracted much attention recently, and the thermal effect is given. However, few investigations focus on the dissipation of the heat converted from the unwanted light. In this paper,an approach of active cooling for CPS is demonstrated. This is achieved by using microchannel cooling technology in heat sinking in CPS to improve the efficiency of heat exchange. In order to explain the mechanism of CPS the function of it and consistence of categories of the unwanted light are detailed firstly. Then microchannel heat sinking is proposed and verified by the heat exchange theory. At last, the design of the CPS with microchannel heat sinking is shown and following experiment is conducted. The final temperature of the device with 1000 W cladding power was demonstrated at last to verify the ability of heat distribution of the CPS component. This suggests that these CPSs can be used to stripe a thousand of watts of light in high power double cladding fiber lasers.

关键词： cladding power stripper double cladding fiber high power laser system microchannel