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A comparative study on Sn macrosegregation behavior of ternary Al-Sn-Cu alloys prepared by gravity casting and squeeze casting

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China Foundry 2023年第1期20卷 63-70页

作者： ming Xu Yan-guo Yin cong-min li cong-chong Duan College of Mechanical Engineering Hefei University of TechnologyHefei 230002China Anhui Yihui New Materials Co. Ltd.Hefei 230000China

A comprehensive study on Sn macrosegregation behavior in ternary Al-Sn-Cu alloys was carried out by comparative analysis between gravity casting and squeeze casting *** microstructure and Sn distribution of the castings were characterized by metallography,scanning electron microscopy(SEM),energy-dispersive X-ray(EDX)spectroscopy,and a direct reading *** show that there are obvious differences in Sn morphology between gravity casting and squeeze casting *** squeeze casting condition,the grain size of the casting is smaller and the distribution ofβ(Sn)is *** effectively reduces the segregation of triangular grain boundary as well as the segregation of *** segregation types of Sn in gravity casting and squeeze casting samples are obviously *** upper surfaces of gravity casting samples show severe negative segregation,while all the lower surfaces have positive *** with gravity casting,squeeze casting solidifies under isostatic *** to the direct contact between the upper surface of the casting and the mold,the casting solidifies faster under higher undercooling degree and ***,the uniform distribution of Sn reduces the segregation phenomenon on the surface of the casting.

关键词： ternary Al-Sn-Cu alloy squeeze casting macrosegregation mechanism

Effects of macrosegregation on mechanical and tribological properties of squeeze casting immiscible bearing alloys

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中国铸造:英文版 2023年第5期20卷 443-451页

作者： ming Xu Yan-guo Yin cong-min li Guo-tao Zhang cong-chong Duan Institute of Tribology School of Mechanical EngineeringHefei University of TechnologyHefei 230002China School of Mechanical Engineering Anhui University of TechnologyMaanshan 243002AnhuiChina Anhui Yihui New Material Co. Ltd.Hefei 230000China

The macrosegregation behaviors of Al-Sn-Cu ternary immiscible alloy castings and their effects on mechanical and tribological properties were *** results demonstrate that Sn and Cu segregate in the casting simultaneously,and the mass fraction of the two elements has a"U"shaped ***,positive and negative segregation occur in the casting,with positive segregation appearing on the top and lower surfaces and negative segregation on the remaining surfaces,with the 1/2 surface(hot node location)having the highest degree of negative ***,the results of Vickers hardness,tensile strength,and elongation show that Sn and Cu cooperatively affect the mechanical properties of *** higher the mass fraction of Sn and Cu elements,the higher the hardness,the greater the tensile strength,and the better the *** findings of the step-by-step loading tests demonstrate that the segregation of Sn and Cu significantly impacts the tribological characteristics of the *** higher the mass fraction of Sn and Cu on the sample surface,the better the tribological characteristics.

关键词： squeeze casting Al-Sn-Cu macrosegregation mechanical properties tribological property

The governance technology for blockchain systems:a survey

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Frontiers of Computer Science 2024年第2期18卷 181-197页

作者： Guocheng ZHU Debiao HE Haoyang AN min LUO cong PENG School of Cyber Science and Engineering Wuhan UniversityWuhan 430072China Shandong Provincial Key Laboratory of Computer Networks Qilu University of Technology(Shandong Academy of Sciences)Jinan 250014China

After the Ethereum DAO attack in 2016,which resulted in significant economic losses,blockchain governance has become a prominent research ***,there is a lack of comprehensive and systematic literature review on blockchain *** deeply understand the process of blockchain governance and provide guidance for the future design of the blockchain governance model,we provide an in-depth review of blockchain *** this paper,first we introduce the consensus algorithms currently used in blockchain and relate them to governance ***,we present the main content of off-chain governance and investigate two well-known off-chain governance ***,we investigate four common on-chain governance voting techniques,then summarize the seven attributes that the on-chain governance voting process should meet,and finally analyze four well-known on-chain governance blockchain projects based on the previous *** hope this survey will provide an in-depth insight into the potential development direction of blockchain governance and device future research agenda.

关键词： blockchain governance off-chain governance on-chain governance voting

Machine learning for predicting fatigue properties of additively manufactured materials

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Chinese Journal of Aeronautics 2024年第4期37卷 1-22页

作者： min YI ming XUE Peihong cong Yang SONG Haiyang ZHANG lingfeng WANG liucheng ZHOU Yinghong li Wanlin GUO State Key Laboratory of Mechanics and Control for Aerospace Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China Institute for Frontier Science Nanjing University of Aeronautics and AstronauticsNanjing 210016China College of Aerospace Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Shenyang Engine Research Institute Shenyang 110015China liaoning Key Laboratory of Impact Dynamics on Aero Engine Shenyang 110015China Science and Technology on Plasma Dynamics Laboratory Air Force Engineering UniversityXi’an 710038China

Fatigue properties of materials by Additive Manufacturing(AM) depend on many factors such as AM processing parameter, microstructure, residual stress, surface roughness, porosities, post-treatments, etc. Their evaluation inevitably requires these factors combined as many as possible, thus resulting in low efficiency and high cost. In recent years, their assessment by leveraging the power of Machine Learning(ML) has gained increasing attentions. A comprehensive overview on the state-of-the-art progress of applying ML strategies to predict fatigue properties of AM materials, as well as their dependence on AM processing and post-processing parameters such as laser power, scanning speed, layer height, hatch distance, built direction, post-heat temperature,etc., were presented. A few attempts in employing Feedforward Neural Network(FNN), Convolutional Neural Network(CNN), Adaptive Network-Based Fuzzy Inference System(ANFIS), Support Vector Machine(SVM) and Random Forest(RF) to predict fatigue life and RF to predict fatigue crack growth rate are summarized. The ML models for predicting AM materials' fatigue properties are found intrinsically similar to the commonly used ones, but are modified to involve AM features. Finally, an outlook for challenges(i.e., small dataset, multifarious features,overfitting, low interpretability, and unable extension from AM material data to structure life) and potential solutions for the ML prediction of AM materials' fatigue properties is provided.

关键词： Additive manufacturing Machine learning Fatigue life Fatigue crack growth rate Prediction

A Study of the Effect of the Miller Cycle on the Combustion of a Supercharged Marine Diesel Engine

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Energy Engineering 2024年第5期121卷 1363-1380页

作者： lingjie Zhao cong li Mechanical and Automotive Engineering School Shanghai University of Engineering ScienceShanghai201600China

The Miller cycle is a program that effectively reduces NOx emissions from marine diesel engines by lowering the maximum combustion temperature in the cylinder,thereby reducing NOx *** effectively investigate the impact of Miller cycle optimum combustion performance and emission capability under high load conditions,this study will perform a one-dimensional simulation of the performance of a marine diesel engine,as well as a threedimensional simulation of the combustion in the cylinder.A 6-cylinder four-stroke single-stage supercharged diesel engine is taken as the research *** chassis dynamometer and other related equipment are used to build the test system,carry out the diesel engine bench test,and collect experimental *** simulation results are compared with the test results,and the error is less than 5%.In this study,the authors will use simulation software to simulate several Miller cycle scenarios designed for early inlet valve closure and analyze the impact of the Miller cycle on combustion and emissions at 100%load *** comparing the flow field distribution of the engine at 1500 r/min condition,it was found that proper EIVC can prolong the ignition latency period and homogeneous fuel-air mixture combustion acceleration,but it can reduce pressure and temperature within the piston chamber and NOx ***,the Miller cycle reduces end-of-compression temperatures,which increases combustion duration and exhaust temperatures,making it difficult to improve fuel economy at the optimum fuel consumption point,and closing the intake valves prematurely leads to excessive fuel ***,temperature and heat release rate within the piston chamber,NOx,and SOOT generation were significantly enhanced.

关键词： Miller cycle EIVC combustion NOx emissions marine diesel

Micro-mechanism Study on the Different Antioxidants Protective Effect of Vegetable Oil by ReaxFF Molecular Dynamics

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CSEE Journal of Power and Energy Systems 2024年第3期10卷 1269-1279页

作者： Haoxi cong Xuefeng Hu Hao Pan Qingmin li State Key Laboratory of Alternate Electrical Power System With Renewable Energy Sources North China Electric Power UniversityBeijing 102206China

The aging problem of vegetable oil has severely restricted the popularization and application of vegetable oil *** antioxidants is the most recommended *** present,there is insufficient research on the micromechanism application of the protective effect of antioxidants on vegetable *** this paper,multiple vegetable oil models with different types and concentrations of antioxidants are *** the molecular dynamics simulation based on ReaxFF is carried out at different temperatures and oxygen *** show that the protective mechanism of antioxidants is to release H and combine this with free radicals generated by the decomposition of unsaturated fatty acids(UFA)in the *** addition,the protective effects of four antioxidants show different *** stronger ones are tert-butyl hydroquinone(TBHQ)and butylated hydroxytoluene(BHT),while the weaker ones are butylated hydroxyanisole(BHA)and propyl gallate(PG).TBHQ has a better protective effect at lower concentrations,but the decomposition of UFA is promoted at higher *** the temperature rises,the decomposition of UFA is *** the addition of oxygen,smaller molecular compounds are easily oxidized,and the decomposition of UFA is *** above research could reveal the microscopic mechanism of antioxidant protection on vegetable oil,providing theoretical references for further exploration of effective vegetable oil aging protection technology.

关键词： Antioxidant molecular dynamics transformer vegetable oil

Fecal microbiota transplantation for irritable bowel syndrome:Current evidence and perspectives

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World Journal of Gastroenterology 2024年第16期30卷 2179-2183页

作者： cong Dai Yu-Hong Huang min Jiang Department of Gastroenterology First Hospital of China Medical UniversityShenyang 110001Liaoning ProvinceChina

In this editorial we comment on the article published in the recent issue of the World journal of *** focus specifically on the mechanisms underlying the effects of fecal microbiota transplantation(FMT)for irritable bowel syndrome(IBS),the factors which affect the outcomes of FMT in IBS patients,and *** has emerged as a efficacious intervention for clostridium difficile infection and holds promise as a therapeutic modality for *** utilization of FMT in the treatment of IBS has undergone scrutiny in numerous randomized controlled trials,yielding divergent *** current frontier in this field seeks to elucidate these variations,underscore the existing knowledge gaps that necessitate exploration,and provide a guideline for successful FMT implementation in IBS *** the same time,the application of FMT as a treatment for IBS confronts several challenges.

关键词： Fecal microbiota transplantation Irritable bowel syndrome Microbiota Randomized controlled trial Meta-analysis

Distributions of Visual Receptive Fields from Retinotopic to Craniotopic Coordinates in the Lateral Intraparietal Area and Frontal Eye Fields of the Macaque

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Neuroscience Bulletin 2024年第2期40卷 171-181页

作者： lin Yang min Jin cong Zhang Ning Qian mingsha Zhang Key Laboratory of Cognitive Neuroscience and Learning Division of PsychologyBeijing Normal UniversityBeijing 100875China Institute of Neuroscience Key Laboratory of Primate NeurobiologyCAS Center for Excellence in Brain Science and Intelligence TechnologyChinese Academy of SciencesShanghai 200031China Department of Neuroscience and Zuckerman Institute Columbia UniversityNew York 10027USA

Even though retinal images of objects change their locations following each eye movement,we perceive a stable and continuous *** possible mechanism by which the brain achieves such visual stability is to construct a craniotopic coordinate by integrating retinal and extraretinal *** have been several proposals on how this may be done,including eye-position modulation(gain fields)of retinotopic receptive fields(RFs)and craniotopic *** the present study,we investigated coordinate systems used by RFs in the lateral intraparietal(liP)cortex and frontal eye fields(FEF)and compared the two *** mapped the two-dimensional RFs of neurons in detail under two eye fixations and analyzed how the RF of a given neuron changes with eye position to determine its coordinate *** same recording and analysis procedures were applied to the two brain *** found that,in both areas,RFs were distributed from retinotopic to craniotopic *** was no significant difference between the distributions in the liP and *** a small fraction of neurons was fully craniotopic,whereas most neurons were between the retinotopic and craniotopic *** distributions were strongly biased toward the retinotopic side but with significant craniotopic *** results suggest that there is only weak evidence for craniotopic RFs in the liP and FEF,and that transformation from retinotopic to craniotopic coordinates in these areas must rely on other factors such as gain fields.

关键词： Reference frames Eye-centered Headcentered Visual stability

Pseudomonotonicity of Nonlinear Transformations on Euclidean Jordan Algebras

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Acta Mathematicae Applicatae Sinica 2024年第1期40卷 192-204页

作者： Yuan-min li School of Mathematics and Statistics Xidian UniversityXi’an710071China

In this paper, we have introduced the concepts of pseudomonotonicity properties for nonlinear transformations defined on Euclidean Jordan algebras. The implications between this property and other P-properties have been studied. More importantly, we have solved the solvability problem of the nonlinear pseudomonotone complementarity problems over symmetric cones.

关键词： Euclidean Jordan algebra nonlinear transformation complementarity problem pseudomonotone