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Microstructure and Mechanical Properties of 50SiMnNiNb Steel by a Novel Quenching-Partitioning-Austempering Heat Treatment

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Chinese Journal of Mechanical Engineering 2009年第5期22卷 645-650页

作者： li hongyan JIN Xuejun School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai 200240 China

For the purpose of reducing weight of steel parts, save raw materials and keep or even improve safety standards, the development of advanced high strength steels is increasingly demanded in the automotive industry and engineering applications. We have proposed a novel heat treatment （quenching-partitioning-austempering treatment, Q-P-A） to obtain steel parts with high strength and good ductility. The Q-P-A process is intended to produce microstructure consisted of carbon-depleted martensite, carbon-enriched retained austenite and nanostructured bainite. Quenching（Q） treatment fabricates mixed microstructure of carbon-supersaturated martensite and certain amounts of untransformed austenite. Partitioning（P） thermal treatment accomplishes fully diffusing of carbon from the supersaturated martensite phase to the untransformed austenite phase and enriching the amount of carbon in untransformed austenite. Further low-temperature austempering（A） process induces incredible thin bainite from the carbon-enriched untransformed austenite. A study of the microstructure and mechanical properties of 50SiMnNiNb steel subjected to the novel Q-P-A treatment is presented. Microstructure is assessed by optical microscope（OM）, field emission scanning electron microscope（FESEM） and transmission electron microscope（TEM）, and the corresponding mechanical properties are measured. The experimental results indicate that attractive mechanical properties of steels during the Q-P-A process are attributed to the complex multi-phase structure. Slender plates of bainite with 20-40 nm thick are generated in the medium carbon steel. Meanwhile, with increasing of the volume fraction of nanostructured bainite, yield strength of steel parts is increased with little degradation of ultimate tensile strength. In this paper, a novel quenching-partitioning-austempering heat treatment is proposed, and the attractive mechanical properties of steels are obtained during the Q-P-A process.

关键词： heat treatment quenching-partitioning-austempering martensite retained austenite nanostructured bainite

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CAPACITY COMMITMENT AND PRICING FOR SUBSTITUTABLE PRODUCTS UNDER COMPETITION

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Journal of Systems Science and Systems Engineering 2012年第4期21卷 443-460页

作者： hongyan li Tianhui YOU Business and Social Science School Aarhus University School of Business Administration Northeastern University

Capacity acquisition and pricing decisions are a company＇s long-term strategic decisions. However, demand uncertainty and substitutability of multiple products cause the difficulty to solve capacity and pricing decision problems. In this paper, we address a multiple product pricing and multiple resource capacity acquisition problem with *** and competition. The company needs to determine capacity commitment for each resource and product prices before demands are realized so that the total profit is maximized. If the demand exceeds the committed capacity, extra amounts can be purchased from the spot market. Variable unit production costs, capacity acquisition and maintenance costs are considered. We first analyze a single company basic problem and find the optimal solutions on prices and capacity. Based on the single company model, we address the two-product, two-firm capacity commitment and pricing problem considering across product and across company price competition factors. The existence and uniqueness of equilibrium on price and capacity commitment are proved, and then we extended the results to the multiple product, multiple company case.

关键词： Capacity commitment multiple product pricing product substitution price competition stochastic demand

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Collaborative supply chain planning under dynamic lot sizing costs with capacity decision

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Journal of Systems Engineering and Electronics 2011年第2期22卷 247-256页

作者： hongyan li Tianhui You Xiaoyi Luo School of Business Administration Northeastern University Shenyang 110004 E R. China Aarhus School of Business Aarhus University Aarhus V 8210 Denmark

Studies show that supply chain cooperation improves supply chain performance. However, it remains a challenge to develop and implement the realistic supply chain cooperation scheme. We investigate a two-echelon supply chain planning problem with capacity acquisition decision under asymmetric cost and demand information. A simple negotiation-based coordination mechanism is developed to synchronize production/order strategies of a supplier and a buyer. The coordination scheme shows how the supplier and the buyer modify their production and order policy in order to find a joint economic lot sizing plan, which saves the overall supply chain cost. The allocation of the cooperation benefit is determined by negotiation. Due to the complexity of the multiple periods, multiple level supply chain lot sizing with capacity decision, a heuristic algorithm is developed to find coordination solutions. Finally, the results of the numerical study indicate the performance of supply chain coordination scheme.

关键词： supply chain coordination joint economic lot sizing negotiation supply chain management capacity acquisition,heuristics.

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Coking wastewater increases micronucleus frequency in mouse in vivo via oxidative stress

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Journal of Environmental Sciences 2013年第10期25卷 2123-2129页

作者： Na Zhu hongyan li Guangke li Nan Sang College of Environment and Resource Center of Environmental Science and Engineering Shanxi University

Coking wastewater has caused serious health risk in coal-producing areas of China, however its toxic effects have not been well understood. The genotoxicity induced by coking wastewater on mice in vivo and its possible oxidative mechanisms were investigated via observing the induction of micronuclei in polychromatic erythrocytes of mouse bone marrow, and subsequently determining the antioxidative enzyme activities （superoxide dismutase Cu, Zn-SOD, Se-dependent glutathione peroxidase, and catalase）, thiobarbituric acid reactive substance contents and protein carbonyl levels in brains and livers of mice. Results showed that the tested coking wastewater caused a significant increase of micronucleus frequencies in a concentration-dependent manner. Also, the sample increased lipid peroxidation and protein oxidation levels, which was accompanied by changes in antioxidative status. Interestingly, pre-treatment with an antioxidant （vitamin C） led to a statistical reduction in the micronucleus frequency caused by coking wastewater. This implies that coking wastewater induces evident genetic damage in mammalian cells, and exposure to polluted areas might pose a potential genotoxic risk to human beings; in the process, oxidative stress played a crucial role.

关键词： micronucleus oxidative stress coking wastewater mouse bone marrow

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Atom Probe and Mssbauer Spectroscopy Investigations of Cementite Dissolution in a Cold Drawn Eutectoid Steel

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Journal of Materials Science & Technology 2010年第9期26卷 776-782页

作者： Na Min Wei li hongyan li Xuejun Jin School of Materials Science an-d Engineering Shanghai University Shanghai 200072 China School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai 200240 China

Mssbauer spectrum and three dimensional atom probes（3DAP） were combined to investigate the mechanism of cementite dissolution in a cold-drawn eutectoid steel at a true strain of *** experimental results suggest that the dislocations play an important role in the dissolution of the cementite by sweeping across the nano-scaled cementite,and transferring carbon from cementite to ferrite inducing cementite *** mechanism of cementite dissolution in the steel is discussed in association with the investigation of nonstoichiometric cementite structure after heavy deformation.

关键词： Eutectoid steel Cementite Three dimensional atoms probe Mssbauer spectrum

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Enhanced time-expanded graph for space information network modeling

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Science China(Information Sciences) 2022年第9期65卷 235-248页

作者： Jiandong li Peng WANG hongyan li Keyi SHI State Key Laboratory of Integrated Service Networks Xidian University

Space information networks(SINs) are responsible for communications, information processing,and earth observation. Traditional time-expanded graphs(TEG) cannot represent the observation, energy,and transceiver resources. Therefore, we propose the enhanced time-expanded graph(ETEG) to jointly model the resource elements of SINs. First, we utilize snapshot graphs to characterize the time-varying properties of the resources. Next, we introduce virtual links and nodes to enhance the TEG, which transforms the transceiver and observation resource constraints into normal capacity and flow conservation ones and simplifies the energy constraints. Then, the maximum flow algorithm is modified to optimally schedule the data flow in SIN. With the ETEG-based maximum flow algorithm, the resources can be jointly optimally scheduled. Finally, the simulation results demonstrate the efficiency and effectiveness of our ETEG.

关键词： enhanced time-expanded graph space information network network modeling heterogeneous resource modeling joint scheduling

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Mechanism and Forecasting Methods for Severe Droughts and Floods in Songhua River Basin in China

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Chinese Geographical Science 2011年第5期21卷 531-542页

作者： li hongyan WANG Yuxin li Xiubin Key Laboratory of Groundwater Resources and Environment Ministry of Education Jilin University Changchun 130021 China Baihan Power Plant of State Grid Xin Yuan Company limited Huadian 132400 China

The influence of various factors, mechanisms, and principles affecting runoff are summarized as periodic law, random law, and basin-wide law. Periodic law is restricted by astronomical factors, random law is restricted by atmospheric circulation, and basin-wide law is restricted by underlying surface. The commensurability method was used to identify the almost period law, the wave method was applied to deducing the random law, and the precursor method was applied in order to forecast runoff magnitude for the current year. These three methods can be used to assess each other and to forecast runoff. The system can also be applied to forecasting wet years, normal years and dry years for a particular year as well as forecasting years when floods with similar characteristics of previous floods, can be expected. Based on hydrological climate data of Baishan (1933-2009) and Nierji (1886-2009) in the Songhua River Basin, the forecasting results for 2010 show that it was a wet year in the Baishan Reservoir, similar to the year of 1995; it was a secondary dry year in the Nierji Reservoir, similar to the year of 1980. The actual water inflow into the Baishan Reservoir was 1.178 × 10 10 m 3 in 2010, which was markedly higher than average inflows, ranking as the second highest in history since records began. The actual water inflow at the Nierji station in 2010 was 9.96 × 10 9 m 3 , which was lower than the average over a period of many years. These results indicate a preliminary conclusion that the methods proposed in this paper have been proved to be reasonable and reliable, which will encourage the application of the chief reporter release system for each basin. This system was also used to forecast inflows for 2011, indicating a secondary wet year for the Baishan Reservoir in 2011, similar to that experienced in 1991. A secondary wet year was also forecast for the Nierji station in 2011, similar to that experienced during 1983. According to the nature of influencing factors,

关键词： Songhua River Basin runoff drought and flood forecasting

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Mountain Effect and Differences in Storm Floods between Northern and Southern Sources of the Songhua River Basin

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Journal of Mountain Science 2012年第3期9卷 431-440页

作者： li hongyan WU Ya'nan li Xiubin Key Laboratory of Groundwater Resources and Environment Ministry of Education Jilin University Changchun 130021 China Baishan Power Plant of State Grid Xin Yuan Company limited Huadian 132400 China

In this study, the differences in annual rainstorm changes in the Second Songhua River Basin and the Nenjiang River basin and their causes were compared from the perspective of mountain effects. The following results were drawn: (1) Altitude effect is the primary factor leading to increased rainstorms in the southern source; (2) Slope effect primarily leads to differences of the weather systems in the two sources, and thus cause the difference of the rainstorms; (3) Slope effect is responsible for the greater fluctuation in the observed floods in the southern source. These landform differences eventually lead to the differences in the characteristics of floods in the southern and northern sources. Commensurability method was used to identify the period of rainstorms in the southern and northern sources. The results showed that although rainstorms do not appear at the same time in the two sources they are characteristic of a 10 years' period in both areas. These results can serve as hydrological references for flood control and long-term flood disaster predictions.

关键词： Mountain effect Songhua River Basin Nenjiang River Basin the Second Songhua RiverBasin Storm flood

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Successive Interference Cancellation and Alignment in K-User MIMO Interference Channels with Partial Unidirectional Strong Interference

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China Communications 2022年第2期19卷 118-130页

作者： Long Suo hongyan li Shun Zhang Jiandong li State Key Laboratory of Integrated Service Networks Xidian UniversityXi’an 710071China Guangzhou Institute of Technology Xidian UniversityGuangzhou 510000China

Recently cellular networks have been densely and heterogeneously deployed indoors and outdoors to expand the network capacity,and thus the in-building propagation loss and the transmit power diversity of access points will exacerbate link heterogeneity and result in partial unidirectional strong *** make full use of the strong interference feature,we propose the successive interference cancellation and alignment(SICA)scheme in the K-user interference channel with partial unidirectional strong *** is designed to transmit two kinds of data streams simultaneously,the alignment streams and superposition *** alignment streams will follow the interference alignment criterion to maintain the optimal degrees of freedom(DoF)performance;the superposition streams are handled via successive interference cancellation at all the strongly interfered receivers to improve the overall achievable *** joint transceiver designs for SICA is modeled as a weighted sum rate(WSR)maximization problem,and then can be alternately solved for a local optimum according to the optimality equivalence between WSR and its corresponding weighted mean square error(WMMSE)*** results have confirmed the sum rate improvement and DoF optimality of the proposed SICA scheme.

关键词： interference alignment successive interference cancellation interference management ultra dense networks

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Regulating the coordination microenvironment of atomic bismuth sites in nitrogen-rich carbon nanosheets as anode for superior potassium-ion batteries

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Journal of Energy Chemistry 2024年第12期99卷 365-374页

作者： Yiye Tan Haoxiang lin Zhisong Chen li Niu hongyan li Department of Materials Science and Engineering College of Chemistry and Materials ScienceJinan UniversityGuangzhou 510632GuangdongChina Guangzhou Key Laboratory of Sensing Materials&Devices School of Chemistry and Chemical EngineeringGuangzhou UniversityGuangzhou 510006 GuangdongChina

Carbon-based materials are recognized as anodes fulling of promise for potassium ion batteries(PIBs)due to advantages of affordable cost and high ***,they still face challenges including structural unstability and slow *** is difficult to achieve efficient potassium storage with unmodified carbonaceous ***,atomic bismuth(Bi)sites with different atom coordinations anchored on carbon nanosheets(CNSs)have been synthesized through a template *** properties of prepared multi-doping carbon anodes Bi-N_(3)S_(1)/CNSs,Bi-N_(3)P_(1)/CNSs and Bi-N_(4)/CNSs were probed in *** configuration Bi-N_(3)S_(1) with stronger charge asymmetry exhibits superior potassium storage performance compared to Bi-N_(3)P_(1) and Bi-N_(4) *** Bi-N_(3)S_(1)/CNSs display a rate capacity of 129.2 mAh g^(-1)even at 10 A g^(-1)and an impressive cyclability characterized by over 5000 cycles at 5 A g^(-1),on account of its optimal coordination environment with more active Bi centers and K^(+)adsorption ***,assembled potassium-ion full cell Mg-KVO//Bi-N_(3)S_(1)/CNSs also shows an outstanding cycling stability,enduring 3000 cycles at 2 A g^(-1).Therefore,it can be demonstrated that regulating the electronic structure of metallic centre M-N_(4) via changing the type of ligating atom is a feasible strategy for modifying carbon anodes,on the base of co-doping metal and non-metal.

关键词： Potassium ion batteries Carbon anodes Co-doping Coordination environment Atomic Bi-N_(3)S_(1)sites

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