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Experimental study on the interfacial delamination in a thermal barrier coating system at elevated temperatures

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2010年第10期11卷 794-803页

作者： peng-fei ZHAO Fu-lin SHANG Department of Engineering Mechanics School of Aerospace Xi 'an Jiaotong University Xi 'an 710049 China

The failure mode and adhesion of thermal barrier coating (TBC) 8YSZ (ZrO2+8% (w/w) Y2O3) deposited on NiCoCrAlTaY bond coat by atmospheric plasma spraying were investigated. A grooved modified three-point bending specimen that can generate a single interface crack to facilitate the control of crack growth was adopted for testing, which was conducted at the ambient temperature of 100 °C. The morphology and composition of fractured surfaces were examined by means of a scanning electron microscopy (SEM) and an energy disperse spectroscopy (EDS). Images and spectrum show that cracks are initiated and propagated exclusively within YSZ layer adjacent to top/bond coat interface. The load-displacement curves obtained exhibit similar shapes that indicate two distinct stages in crack initiation and stable crack growth. Finite element analyses were performed to extract the adhesion strength of the TBCs. The delamination toughness of the plasma-sprayed 8YSZ coatings at 100 °C, in terms of critical strain energy release rate Gc, can be reliably obtained from an analytical solution.

关键词： Thermal barrier coating (TBC) Three-point bending test Finite element analysis Delamination toughness

Mapping global forest biomass and its changes over the first decade of the 21st century

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Science China Earth Sciences 2019年第3期62卷 585-594页

作者： Anping CHEN Shushi peng Songlin fei Department of Forestry and Natural Resources Purdue University The Woods Hole Research Center Laboratoire des Sciences du Climat et de l'Environnement(LSCE) CEA-CNRS-UVSQ

Forests played an important role in carbon sequestration during the past two decades. Using a model tree ensemble method(MTE) to regress the seven reflectance bands of EOS-Terra-MODIS satellite data against country level forest biomass carbon density(BCD) of 2001–2005 provided by United Nations' s Forest Resource Assessment(FRA), we developed a global map of forest BCD at 1 km×1 km resolution for both 2001–2005 and 2006–2010. For 2006–2010, the total global forest biomass carbon stock is estimated as 279.6±7.1 Pg C, and the tropical forest biomass carbon stock is estimated as 174.4±5.4 Pg C. During the first decade of the 21 st century, we estimated an increase of global forest biomass of 0.28±0.75 Pg C yr^(-1). Tropical forest biomass carbon stock slightly decreased(-0.31±0.60 Pg C yr^(-1)); by contrast, temperate and boreal forest biomass increased(0.58±0.28 Pg C yr^(-1)) during the same period. Our estimation of the global forest biomass carbon stock and its changes is subject to uncertainties due to lack of extensive ground measurements in the tropics, spatial heterogeneity in large countries, and different definitions of forest. The continuously monitoring of forest biomass carbon stock with MODIS satellite data will provide useful information for detecting forest changes.

关键词： Forest biomass Carbon stock Model tree ensemble(MTE) MODIS Remote sensing

Variations in soil moisture over the ‘Huang-Huai-Hai Plain＇ in China due to temperature change using the CNOP-P method and outputs from CMIP5

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Science China Earth Sciences 2017年第10期60卷 1838-1853页

作者： SUN GuoDong peng fei MU Mu State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG) Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Institute of Atmospheric Sciences Fudan University Shanghai 200433 China University of Chinese Academy of Sciences Beijing 100049 China Numerical Weather Prediction Center China Meteorological Administration Beijing 100081 China

In this study, the variations in surface soil liquid water(SSLW) due to future climate change are explored in the‘Huang-Huai-Hai Plain'(‘3H') region in China with the Common Land Model(CoLM). To evaluate the possible maximum response of SSLW to climate change, the combination of the conditional nonlinear optimal perturbation related to the parameter(CNOP-P) approach and projections from 10 general circulation models(GCMs) of the Coupled Model Intercomparison Project5(CMIP5) are used. The CNOP-P-type temperature change scenario, a new type of temperature change scenario, is determined by using the CNOP-P method and constrained by the temperature change projections from the 10 GCMs under a high-emission scenario(the Representative Concentration Pathway 8.5 scenario). Numerical results have shown that the response of SSLW to the CNOP-P-type temperature scenario is stronger than those to the 11 temperature scenarios derived from the 10 GCMs and from their ensemble average in the entire ‘3H' region. In the northern region, SSLW under the CNOP-P-type scenario increases to0.1773 m^3 m^(-3); however, SSLW in the scenarios from the GCMs fluctuates from 0.1671 to 0.1748 m^3 m^(-3). In the southern region,SSLW decreases, and its variation(–0.0070 m^3 m^(-3)) due to the CNOP-P-type scenario is higher than each of the variations(–0.0051 to –0.0026 m^3 m^(-3)) due to the scenarios from the GCMs.

关键词： CNOP-P Surface soil liquid water CMIP5 Climate change Seasonal and regional heterogeneity

A Novel Model Calibration Method for Active Magnetic Bearing Based on Deep Reinforcement Learning

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Guidance, Navigation and Control 2023年第3期3卷 110-128页

作者： Bingyun Yang Cong peng fei jiang Sumu Shi College of Automation Engineering Nanjing University of Aeronautics and Astronautics Nanjing 211106P.R.China

Active magnetically suspended control moment gyro is a novel attitude control actuator for *** is mainly composed of rotor,active magnetic bearing(AMB)and *** a crucial supporting component of control moment gyro,the performance of AMB is directly related to the stability of the rotor system and pointing precision of the ***,calibrating the parameters of AMB is essential for the realization of super-quiet *** paper proposed a model calibration method,known as the deep reinforcement learningbased model calibration frame(DRLMC).First,the dynamics of magnetic bearing with damage degradation over its life cycle are ***,the calibration process is formulated as a Markov Decision Process(MDP),and reinforcement learning(RL)is employed to infer the degradation *** addition,experience replay and target network update mechanism are introduced to guarantee *** results demonstrate that the proposed method identi¯es force-current factor of AMB during its degradation process e®***,additional experiments con¯rm the robustness of the DRLMC approach.

关键词： Control moment gyro active magnetic bearing model calibration reinforcement learning

A Novel Through-the-Wall Imaging Algorithm Combined with Phase Shift Migration and NUFFT

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Chinese Journal of Electronics 2017年第5期26卷 1096-1100页

作者： ZHANG peng fei peng WEN Xin NIAN Feng Institute of Radio Metrology and Measurement

This paper proposes a novel Through wall imaging(TWI) algorithm combined with phase compensation and Nonuniform fast Fourier transform(NUFFT).The wall effect is cancelled with phase compensation,which is implemented by multiplying the conjugated wall transmissivity with the received *** NUFFT technique is implemented to calculate the imaging *** proposed method has two merits:The phase compensation avoids a time-consuming calculation of the incidences angles;the image is reconstructed more accurately and efficiently than the conventional Interpolation-fast Fourier transform(IPFFT) *** new method is implemented on 2D synthetic-generated data and experimental *** results demonstrate that our method generates high quality focused images and achieves target geometrical identification within a very short time.

关键词： Phase shift migration(PSM) Nonuniform Fourier transform(NUFFT) Through-the-wall imaging(TWI)

Coupling of RANS and BEM Solvers for Simulation of Propeller Behind the Hull in Full Appended Model

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China Ocean Engineering 2024年第3期38卷 424-438页

作者： Saeed NAJAFI Mehdi POURMOSTAFA LIU peng-fei Iranian National Institute for Oceanography and Atmospheric Science(INIOAS) Tehran 14155-4781Iran Department of Maritime Engineering Amir Kabir University of TechnologyTehran 15875-4413Iran Marine Offshore and Subsea TechnologySchool of EngineeringNewcastle UniversityNewcastle upon TyneNE17RUUK

To design a propeller for ship power plant,the interaction between ship hull and propeller must be taken into *** main concern is to apply the wake effect of ship stern on the propeller *** this paper,a coupled BEM(Boundary Element Method)/RANS(Renolds-Averaged Navier−Stokes)solver is used to simulate propeller behind the hull in the self-propulsion *** motivation of this work is to develop a practical tool to design marine propulsion system without suffering long computational *** unsteady boundary element method which is also known as panel method is chosen to estimate the propeller *** wakes are treated using a time marching wake alignment ***,a RANS code coupled with VoF equation is developed to consider the ship motions and wake field effects in the problem.A coupling algorithm is developed to interchange ship wake field to the potential flow solver and propeller thrust to the RANS *** on the difference between hull resistance and the propeller thrust,a PI controller is developed to compute the propeller RPM in every time *** of the solver is carried out using the towing tank test report of a 50 m oceanography research *** factor and trust deduction coefficient are estimated ***,the wake rollup pattern of the propeller in open water is compared with the propeller in real wake field.

关键词： RANS BEM coupled method ship propeller self-propulsion wake sheet pattern

Product platform architecture for cloud manufacturing

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Advances in Manufacturing 2020年第3期8卷 331-343页

作者： Wei Wei Feng Zhou peng-fei Liang School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191People’s Republic of China

Cloud manufacturing is emerging as a new manufacturing paradigm and an integrated *** adapt to the increasing challenges of the traditional manufacturing industry transforming toward service-oriented and innovative manufacturing,this paper proposes a product platform architecture based on cloud ***,a framework for the product platform for cloud manufacturing was *** proposed architecture is composed of five layers:resource,cloud technology,cloud service,application,and user ***,several key enabling technologies for forming the product platform were ***,the product platform for cloud manufacturing built by a company was taken as an application example to illustrate the architecture and functions of the *** validity and superiority of the architecture were verified.

关键词： Cloud manufacturing Cloud service Product platform Architecture Product collaborative design

Dynamics and control strategies of infectious disease under different scenarios on hierarchical geographical networks

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Chinese Physics B 2019年第12期28卷 400-410页

作者： Xun Ma Ya-peng Cui Xiao-Li Yan Shun-jiang Ni Shi-fei Shen Institute of Public Safety Research Tsinghua UniversityBeijing 100084China Department of Engineering Physics Tsinghua UniversityBeijing 100084China Beijing Key Laboratory of City Integrated Emergency Response Science Beijing 100084China

Human settlements are embedded in traffic networks with hierarchical structures. In order to understand the spreading mechanism of infectious diseases and deploy control measures, the susceptible-infected-removed spreading process is studied with agents moving globally on the hierarchical geographic network, taking into account agents’ preference for node layers and memory of initial nodes. We investigate the spreading behavior in the case of global infection under different scenarios, including different directions of human flow, different locations of infection source, and different moving behaviors of agents between layers. Based on the above-mentioned analysis, we propose screening strategies based on layer rank and moving distance, and compare their effects on delaying epidemic spreading. We find that in the case of global infection,infection spreads faster in high layers than in low layers, and early infection in high layers and moving to high layers both accelerate epidemic spreading. Travels of high-layer and low-layer residents have different effects on accelerating epidemic spreading, and moving between high and low layers increases the peak value of new infected cases more than moving in the same layer or between adjacent layers. Infection in intermediate nodes enhances the effects of moving of low-layer residents more than the moving of high-layer residents on accelerating epidemic spreading. For screening measures, improving the success rate is more effective on delaying epidemic spreading than expanding the screening range. With the same number of moves screened, screening moves into or out of high-layer nodes combined with screening moves between subnetworks has better results than only screening moves into or out of high-layer nodes, and screening long-distance moves has the worst results when the screening range is small, but it achieves the best results in reducing the peak value of new infected cases when the screening range is large enough. This

关键词： disease spreading hierarchical geographical networks screening strategies

Adaptive integral dynamic surface control based on fully tuned radial basis function neural network

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Journal of Systems Engineering and Electronics 2010年第6期21卷 1072-1078页

作者： Li Zhou Shumin fei Changsheng jiang Key Laboratory of Measurement and Control of CES of Ministry of Education Southeast University Nanjing 210096 R R. China School of Automation Southeast University Nanjing 210096 R R. China College of Automation Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016 R R. China

An adaptive integral dynamic surface control approach based on fully tuned radial basis function neural network （FTRBFNN） is presented for a general class of strict-feedback nonlinear systems,which may possess a wide class of uncertainties that are not linearly parameterized and do not have any prior knowledge of the bounding *** is employed to approximate the uncertainty online,and a systematic framework for adaptive controller design is given by dynamic surface control. The control algorithm has two outstanding features,namely,the neural network regulates the weights,width and center of Gaussian function simultaneously,which ensures the control system has perfect ability of restraining different unknown uncertainties and the integral term of tracking error introduced in the control law can eliminate the static error of the closed loop system effectively. As a result,high control precision can be *** signals in the closed loop system can be guaranteed bounded by Lyapunov ***,simulation results demonstrate the validity of the control approach.

关键词： adaptive control integral dynamic surface control fully tuned radial basis function neural network.