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Yuming Qi,Tengwu He,Miaolin Feng 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.7
Adding nanotwins to a metal could be a way to effectively improve its strength without suppressing its tensile ductility, whichsuggests that their unique nanostructure may alter microstructure evolution and deformation mechanisms. In this work, weperform a molecular dynamics-based tension simulation of two-dimension (2D) polycrystalline copper (Cu) with embeddednanotwins under uniaxial stress conditions. The results of MD-simulation reveal that the spacing of the twin boundarieshad a significant effect on the mechanical properties of nanotwinned materials. Specifically, an irregular relationship isfound between the twin boundary spacing ( DT ) and the strength of the material. It exhibits that the peak stress reached amaximum at DT = 12.5 nm and decreased thereafter with increasing average DT . However, flow stress reaches a maximumat a critical value of DT = 7 nm. According to the analysis of microstructure evolution, the presence of nanotwins hinder themotion of partial dislocations and stacking faults, and the stress-concentrated region leads to the transition from coherenttwin boundaries to incoherency. The stress-concentrated region locates in the step of incoherent would release the intrinsicstacking faults responsible for the formation of hierarchical contraction nanotwins stacking faults which efficiently improvesthe strength of Cu. In addition, as the tension proceeds, some samples begin to display the secondary twinning. This workwill be helpful for further investigation the nucleation and evolution of 2D nanotwinned metals and for formulating effectivestrength criteria for 2D nanotwinned metals.
Yuming Zhao 보안공학연구지원센터 2016 International Journal of u- and e- Service, Scienc Vol.9 No.7
The optimal scheduling of crude-oil operation in refineries has been researched by various groups during the past decade. Different mixed integer linear programming or mixed nonlinear programming formulations are derived. This paper proposes a novel MINLP formulation with multiple charging tanks charging a distiller overlapingly and oil residency time constraint that is based on multi-operation sequencing with synchronized start time (MOS-SST). It is different from previous formulations because of its consideration for oil residency time constraint and multiple charging tanks charging a distiller overlapingly. A branch and bound algorithm combined with the Lagrangian Relaxation Subgradient Optimization algorithm is proposed to solve this model, resulting in a satisfactory optimal result.
Research on Integrated Optimization of the Reverse Logistics Network
Yuming Luo 보안공학연구지원센터 2016 International Journal of u- and e- Service, Scienc Vol.9 No.7
Considered the integrate of forward and reverse logistics, the separability of recycle products, the timeliness of recycle products, the paper established a location-routing-inventory control optimization model with batch transportation of recycle products. A matching hybrid genetic algorithm containing heuristic rule was introduced according the characteristics above. The algorithm used three-stage real-code that represents the transport order of vehicles. And the quantity of new products and recycle products will be determined too. The unreasonable solution will be eliminated in the iterative process of genetic algorithm. The simulated test analysis shows the validity and the correctness of the model and algorithm.
Influence of Carbon Fiber on Corrosion Behavior of Carbon Steel in Simulated Concrete Pore Solutions
( Yuming Tang ),( Yuchao Dun ),( Guodong Zhang ),( Xuhui Zhao ),( Yu Zuo ) 한국부식방식학회 2017 Corrosion Science and Technology Vol.16 No.4
Galvanic current measurement, polarization curves, electrochemical impedance spectroscopy and weight loss test were used to study the corrosion behavior of carbon steel before and after carbon fibers coupling to the carbon steel in simulated concrete pore solutions, and the film composition on the steel surface was analyzed using XPS method. The results indicate that passive film on steel surface had excellent protective property in pore solutions with different pH values (13.3, 12.5 and 11.6). After coupling with carbon fibers the area ratio of carbon steel to carbon fiber was 12.31), charge transfer resistance Rct of the steel surface decreased and the Fe3+/Fe2+ value in passive film decreased. As a result, stability of the film decreased and the corrosion rate of steel increased. Decreasing of the area ratio of steel to carbon fiber from 12.3 to 6.15 resulted in the decrease in Rct and the increase in corrosion rate. Especially in the pore solution with pH 11.6, the coupling leads the carbon steel to corrode easily.
( Yuming Song ),( Xueyun He ),( Guan Gui ),( Yan Liang ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.5
Doubly-selective (DS) fading channel is often occurred in many orthogonal frequency division multiplexing (OFDM) communication systems, such as high-speed rail communication systems and underwater acoustic (UWA) wireless networks. It is challenging to provide an accurate and fast estimation over the doubly-selective channel, due to the strong Doppler shift. This paper addresses the doubly selective channel estimation problem based on complex exponential basis expansion model (CE-BEM) in OFDM systems from the perspective of distributed compressive sensing (DCS). We propose a novel DCS-based improved sparsity adaptive matching pursuit (DCS-IMSAMP) algorithm. The advantage of the proposed algorithm is that it can exploit the joint channel sparsity information using dynamic threshold, variable step size and tailoring mechanism. Simulation results show that the proposed algorithm achieves 5dB performance gain with faster operation speed, in comparison with traditional DCS-based sparsity adaptive matching pursuit (DCS-SAMP) algorithm.
Yuming Dong,Hui Zhao,Zhiliang Wang,Guangli Wang,Aizhen He,Pingping Jiang 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.1
ZnO nanoparticles were synthesized through a facile route and were used as ozonation catalysts. With the increase of calcination temperature (150-300 oC), surface hydroxyl groups and catalytic efficiency of asobtained ZnO decreased remarkably, and the ZnO obtained at 150 oC showed the best catalytic activity. Compared with ozonation alone, the degradation efficiency of phenol increased above 50% due to the catalysis of ZnO-150. In the reaction temperatures range from 5 oC to 35 oC, ZnO nanocatalyst revealed remarkable catalytic properties, and the catalytic effect of ZnO was better at lower temperature. Through the effect of tertbutanol on degradation of phenol and the catalytic properties of ZnO on degradation of nitrobenzene, it was proposed that the degradation of phenol was ascribed to the direct oxidation by ozone molecules based on solidliquid interface reaction.
Research on Prediction of Reverse Returned Logistics Based on Grey-Markov Model
Yuming Luo 보안공학연구지원센터 2016 International Journal of u- and e- Service, Scienc Vol.9 No.8
In order to improve the prediction accuracy of reverse returned logistics, considering it has the characteristics of high volatility and uncertainty, the paper used the theory of Markov Chain to modify the result of Grey prediction. And a Grey-Markov prediction model was established. Several parallel region has been divided used the prediction curve of Grey prediction model as symmetric center. And each region was a state interval. A practical example show that the average relative error rate and the variance ratio of Grey-Markov prediction model was smaller, and the prediction accuracy is higher comparing with the Grey prediction model. The model is effective and feasible.
Yuming Zhou,Xiaoqin Fu,Xiaoli Sheng,Zhiwei Fu,Shuo Zhao,Zewu Zhang,Yiwei Zhang 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.6
Well-dispersed hierarchical zeolite Y, structure-directed by ionic liquid 1-methyl-3-[3'-(trimethoxysilyl) propyl] imidazolium chloride, was synthesized for the first time using a novel ultrasonic/microwave synergistic synthesis (UMSS). The time required for the synthesis of zeolite Y by UMSS method was remarkably reduced to 6 h instead of 24 h under conventional hydrothermal conditions. The structures of all samples were characterized by XRD, BET, FT-IR, SEM and TEM. The results clearly demonstrated that the UMSS is a promising strategy to achieve zeolite Y with improved crystallinity, large BET surface area, bulky mesopore volume, well-dispersed morphology, small zeolite nanoparticle. The catalytic activity of hierarchically micro-mesoporous zeolite Y was evaluated by using the alkylation of o-xylene with styrene. Mesoporous zeolite Y synthesized by UMSS method showed significantly higher catalytic activity, stability and reusability, compared with conventional hydrothermal synthesis. It might be ascribed to its large mesoporous volume, small crystal nanoparticle and high surface area, minimizing the diffusion length as the reactant molecules diffuse into the pores, and correspondingly the products diffuse out of zeolites. This study suggests that UMSS method is a good alternative for the synthesis of micro-mesoporous zeolite Y, which may be of remarkable benefit for industrial applications.