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Effect of matrix structure on mechanical properties and dry rolling-sliding wear performance of alloyed ductile iron

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Journal of Iron and Steel Research International 2019年第8期26卷 888-897页

作者： hua Zhang Yan-xin Wu Qiu-ju Li xin Hong State Key Laboratory of Advanced Special Steel and Shanghai Key Laboratory of Advanced Ferrometallurgy and School of Materials Science and Engineering Shanghai University Shanghai 200072 China Jiangsu Yonggang Group Co. Ltd. Zhangjiagang 215628 Jiangsu China Institute of Engineering Technology University of Science and Technology Beijing Beijing 100083 China

The influence of matrix structure on mechanical properties and dry rolling-sliding wear performance of alloyed ductile iron was examined. Four kinds of alloyed ductile irons with different matrix structures were produced through an adequate balance of alloying elements. Tensile tests and dry rolling-sliding wear tests were carried out at room temperature. The results show that yield strength and ultimate tensile strength increase, while elongation decreases until the matrix fully becomes pearlite. The lower matrix hardness results in more graphite emerging on the contact surface, which yields the decrease in friction coefficient. Besides, the wear rate decreases with the increase in matrix hardness among alloyed ductile irons except that with full pearlite matrix, the wear performance of which seems to be deteriorated due to poor fracture toughness. The main wear mechanism is delamination under an air-cooling condition. Based on the results of mechanical and wear tests, ductile iron with about 80% pearlite exhibits better wear performance as well as relatively reasonable mechanical properties.

关键词： Ductile iron Microstructure Mechanical property Wear Delamination

Selection Method for New Energy Output Guaranteed Rates Considering Optimal Energy Storage Configuration

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 539-547页

作者： xin Cheng Tong Wu Wei yao Yan Yang Guangdong Power Grid Corporation Guangzhou 510620China State Key Laboratory of Advanced Electromagnetic Engineering and Technology and School of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074China

The output of new energy represented by wind power and photovoltaic power features volatility and randomness. It is a practical approach to use the guaranteed rate with statistical characteristics to analyze the output coefficient of new energy. However, there is a lack of analysis and demonstration on the value of the new energy output guaranteed rate. To solve this problem, a selection method for the new energy output guaranteed rate considering optimal energy storage configuration is proposed. First, the influence of the new energy output guaranteed rate on the new energy output coefficient is analyzed. Secondly, with the goal of minimizing the comprehensive costs, an optimal configuration model of energy storage based on the output guaranteed rate of new energy is constructed, and particle swarm optimization is used for the optimization solution. Then, according to the optimal energy storage configuration results under different guaranteed rates, a reasonable new energy output guaranteed rate is determined by maximizing the comprehensive benefits obtained from energy storage. Finally, an example applied to the power grid in an area of Guangdong in Southern China is provided to illustrate the effectiveness of the proposed method.

关键词： Energystorage optimization guaranteed output guaranteed rate new energy consumption

Parallel exploration via negatively correlated search

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Frontiers of Computer Science 2021年第5期15卷 123-135页

作者： Peng YANG Qi YANG Ke TANG xin yao Guangdong Provincial Key Laboratory of Brain-inspired Intelligent Computation Department of Computer Science and EngineeringSouthern University of Science and TechnologyShenzhen 518055China

Effective exploration is key to a successful search *** recently proposed negatively correlated search(NCS)tries to achieve this by coordinated parallel exploration,where a set of search processes are driven to be negatively correlated so that different promising areas of the search space can be visited *** successful applications of NCS,the negatively correlated search behaviors were mostly devised by intuition,while deeper(e.g.,mathematical)understanding is *** this paper,a more principled NCS,namely NCNES,is presented,showing that the parallel exploration is equivalent to a process of seeking probabilistic models that both lead to solutions of high quality and are distant from previous obtained probabilistic *** learning,for which exploration is of particular importance,are considered for empirical *** proposed NCNES is applied to directly train a deep convolution network with 1.7 million connection weights for playing Atari *** results show that the significant advantages of NCNES,especially on games with uncertain and delayed rewards,can be highly owed to the effective parallel exploration ability.

关键词： evolutionary computation reinforcement learning exploration

Fractionated and Confined Crystallization of Polybutene-1 in Immiscible Polypropylene/Polybutene-1 Blends

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Chinese Journal of Polymer Science 2018年第7期36卷 859-865页

作者： yao Xu Chen-Guang Liu hua-Rong Nie Ai-hua He Shandong Provincial Key Laboratory of Olefin Catalysis and Polymerization Key Laboratory of Rubber-Plastics (Ministry of Education) School of Polymer Science and Engineering Qingdao University of Science and Technology

In this work, the crystallization of immiscible polypropylene （PP）/polybutene-1 （PB） blends, in particular the effect of crystal morphology of PP （HTC, high Tm component） on the subsequent crystallization behavior of PB （LTC, low Tm component） was studied. Herein, we firstly indicated that PP/PB blends were not completely compatible but characterized as the LCST-like phase diagram above the melting temperature of PP. Crystallization of PP at different crystallization temperatures brought about different PP crystal morphologies and PB was segregated and confined at different locations. Much larger-sized domain of PB component appeared in PP spherulites resulting from the effects of non-negligible phase separation and the slower PP crystallization rate as PP crystallized at high temperature. As temperature continued to fall below Tm of PB, the fractionated and confined crystallization of PB occurred in the framework of PP spherulites, reflected by the decreased crystallization temperature （To） of PB and the formation of form I＇ beside form II. Notably, if PP previously crystallized at high Tc, fractionated crystallization of PB became predominant and confined crystallization of PB became weak due to the much wider droplet-size distribution of PB domains.

关键词： Polypropylene Polybutene Confined crystallization Morphology

Application of a support vector machine for prediction of slope stability

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Science China(Technological Sciences) 2014年第12期57卷 2379-2386页

作者： XUE xin hua YANG xing Guo CHEN xin State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan University College of Water Resource and Hydropower Sichuan University

Slope stability estimation is an engineering problem that involves several parameters. To address these problems, a hybrid model based on the combination of support vector machine(SVM) and particle swarm optimization(PSO) is proposed in this study to improve the forecasting performance. PSO was employed in selecting the appropriate SVM parameters to enhance the forecasting accuracy. Several important parameters, including the magnitude of unit weight, cohesion, angle of internal friction, slope angle, height, pore water pressure coefficient, were used as the input parameters, while the status of slope was the output parameter. The results show that the PSO-SVM is a powerful computational tool that can be used to predict the slope stability.

关键词： slope stability support vector machine particle swarm optimization prediction

Instantaneous sediment transport formula for sheet flow beneath asymmetric wave and current

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Journal of Hydrodynamics 2022年第4期34卷 712-724页

作者： xin-yu Hu Zhong-hua Weng xin Chen Hai-fei Liu The Key Laboratory of Water and Sediment Sciences of Ministry of Education School of EnvironmentBeijing Normal UniversityBeijing100875China Pearl River Water Resources Research Institute Pearl River Water Resources CommissionGuangzhou 510611China College of Water Resources and Civil Engineering China Agricultural UniversityBeijing 100083China

An instantaneous formula is obtained for the sheet flow transport beneath the wave and the current by a product integration of the concentration and velocity profiles over the mobile seabed. The formula involves: (1) The product of the erosion depth and the free stream velocity, which can be reduced to the Shields parameter of power 3/2 in accordance with the classical formulae. (2) The ratio of the wave boundary layer thickness to the erosion depth. The formula incorporates the effects of the acceleration and the phase lag on the erosion depth, the asymmetric wave boundary layer and the wave-current interaction. The validation of the formula is made by the data obtained from the oscillatory tunnels covering a wide range of wave-current and sediment conditions. The instantaneous sediment transport rate is compared with the power function of the velocity with different exponents. The formula consists of a wave force part and a current force part and their relative importance depends on the wave shapes. The present formula gives very good results for the net sediment transport as compared to several existing steady and unsteady formulae. The net sediment transport rates are affected by not only the acceleration, the phase lag and the wave-current interaction, but also the asymmetric boundary layer development.

关键词： Boundary layer thickness erosion depth instantaneous formula sediment transport rate wave and current

Two-dimension fluorescence correlation spectroscopy to characterize the binding of organic ligands with zinc in eutrophic lake

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Chinese Chemical Letters 2015年第2期26卷 205-209页

作者： xin Liu hua Lv hua-Cheng Xu College of Materials Science and Engineering Nanjing Forestry University State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography and LimnologyChinese Academy of Sciences

Metal binding of organic ligands can definitely affect its environmental behavior in waters,while information on the binding heterogeneity with different organic ligands is still lacked till *** this study,the binding of zinc with organic matters associated with cyanobacterial blooms,including dissolved organic matters（DOM） and attached organic matters（AOM）,were studied by using fluorescence quenching titration combined with two-dimensional correlation spectroscopy（2D-COS）.Metal-induced fluorescent quenching was obviously observed both for DOM and AOM,indicating the formation of metal-ligand *** with the one-dimensional spectra,2D-COS revealed the sequences of metal-ligand interaction with the following orders：276 nm 〉 232 ran for DOM and232 nm 〉 276 nm for ***,the modified Stern-Volmer model showed that the binding constant（logKM） of 276 nm in DOM was higher than that of 232 nm（4.93 vs.4.51）,while AOM was characterized with a high binding affinity for 232 nm（log KM：4.83）.The ranks of log KM values were consistent with the sequential orders derived from 2D-COS results both for the two *** quenching titration combined with 2D-COS was an effective method to characterize the metal-ligand interaction.

关键词： Metal binding Eutrophic lakes Dissolved organic matters(DOM) Attached organic matters(AOM) Two-dimensional correlation spectroscopy(2D-COS)

XGBoost-based model for predicting hydrogen content in electroslag remelting

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Journal of Iron and Steel Research International 2023年第5期30卷 887-896页

作者： Yu-xiao Liu Yan-wu Dong Zhou-hua Jiang Yu-shuo Li Wei Zha yao-xin Du Shu-yang Du School of Metallurgy Northeastern UniversityShenyang 110819LiaoningChina Key Laboratory of Ecological Metallurgy of Multimetallic Mineral Northeastern UniversityShenyang 110819LiaoningChina State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819LiaoningChina

An Xtreme Gradient Boosting(XGBoost)-based endpoint hydrogen content prediction model was proposed for the electroslag remelting process,the data collected in the field were pre-processed,and the characteristic variables of the physical parameters related to the variation of hydrogen content in the electroslag remelting process were selected by machine learning analysis and metallurgical *** kernel ridge regression model,ridge regression model,XGBoost model,support vector regression model and gradient boosting regression model were developed and validated using the electroslag remelting data collected from the steel mills,and the model structure and parameters were adjusted several *** prediction accuracy of hydrogen content was compared *** XGBoost model was validated for the test set with the following hit rates:70.59%,82.35% and 100% for the endpoint hits at the allowable hydrogen content error of ±0.05×10^(-6),±0.10×10^(-6) and ±0.50×10^(-6),respectively.

关键词： Electroslag remelting Hydrogen content Machine learning XGBoost Prediction model

From our roots, we grow

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Zoological Research 2019年第6期40卷 471-475页

作者： Yong-Gang yao hua Shen Kunming Institute of Zoology Chinese Academy of SciencesKunming Yunnan 650223China

Located at the head of the Indo-Burma biodiversity hotspot,the Kunming Institute of Zoology (KIZ), Chinese Academy of Sciences (CAS), serves as China’s main center for research into the diverse animal and ecological ... 详细信息

关键词： Kunming Institute of Zoology ecological resources