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Harmonia: Explicit Congestion Notification and Credit-Reservation Transport Converged Congestion Control in Datacenters

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Journal of Computer Science & Technology 2021年第5期36卷 1071-1086页

作者： Ding-Huang Hu de-zun dong Yang Bai Shan Huang Ze-Jia Zhou Zi-Hao Wei Xiang-Ke Liao College of Computer Science and Technology National University of Defense TechnologyChangsha 410073China

Bursty traffic and thousands of concurrent flows incur inevitable network congestion in datacenter networks(DCNs)and then affect the overall *** transport protocols are developed to mitigate the network congestion,including reactive and proactive *** schemes use different congestion signals,such as explicit congestion notification(ECN)and round trip time(RTT),to handle the network congestion after congestion ***,with the growth of scale and link speed in datacenters,reactive schemes encounter a significant problem of slow responding to *** the contrary,proactive protocols(e.g.,credit-reservation protocols)are designed to avoid congestion before it occurs,and they have the advantages of zero data loss,fast convergence and low buffer *** credit-reservation protocols have not been widely deployed in current DCNs(e.g.,Microsoft,Amazon),which mainly deploy ECN-based protocols,such as data center transport control protocol(DCTCP)and data center quantized congestion notification(DCQCN).And in an actual deployment scenario,it is hard to guarantee one protocol to be deployed in every server at one *** credit-reservation protocol is deployed to DCNs step by step,the network will be converted to multi-protocol state and will face the following fundamental challenges:1)unfairness,2)high buffer occupancy,and 3)heavy tail ***,we propose Harmonia,aiming for converging ECN-based and credit-reservation protocols to fairness with minimal *** the best of our knowledge,Harmonia is the first to address the trouble of harmonizing proactive and reactive congestion *** the common ECN-based protocols-DCTCP and DCQCN,Harmonia leverages forward ECN and RTT to deliver real-time congestion information and redefines feedback *** the evaluation,the results show that Harmonia effectively solves the unfair link allocation,eliminating the timeouts and addressing the buffer overflow.

关键词： datacenter credit-reservation protocol ECN-based(explicit congestion notification based)protocol multiprotocol converging

High Performance Interconnect Network for Tianhe System

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Journal of Computer Science & Technology 2015年第2期30卷 259-272页

作者：廖湘科庞征王克非卢宇彤谢旻夏军董德尊所光 College of Computer National University of Defense Technology Changsha 410073 Science and Technology on Parallel and Distributed Processing Laboratory National Changsha 410073 China China University of Defense Technology State Key Laboratory of High Performance Computing National University of Defense Technology Changsha 410073 China

In this paper, we present the Tianhe-2 interconnect network and message passing services. We describe the architecture of the router and network interface chips, and highlight a set of hardware and software features effectively supporting high performance communications, ranging over remote direct memory access, collective optimization, hardwareenable reliable end-to-end communication, user-level message passing services, etc. Measured hardware performance results are also presented.

关键词： Tianhe-2 supercomputer interconnect network router architecture network interface architecture user-level message passing

Mechanical properties and microstructure of Mg-treated and Catreated industrial H13 steel after quenching and tempering

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Journal of Iron and Steel Research International 2024年第8期31卷 1987-2001页

作者： Jun-ying Yue dong Hou de-yong Wang Tian-peng Qu Xiang-long Li Jun Tian School of Iron and Steel Soochow UniversitySuzhou 215021JiangsuChina

The effect of magnesium treatment and calcium treatment on the microstructure and mechanical properties of industrial H13 steel after quenching and tempering was *** impact toughness and tensile tests were mainly carried out,and the microstructure was observed by scanning electron microscopy,electron backscattered diffraction,and X-ray *** results show that magnesium treatment is still feasible in industrial *** is mainly manifested in the refinement of lath martensite and *** with calcium treatment,the prior austenite grains and carbides size of industrial H13 steel treated with magnesium decreased by 3.17μm after *** quenching and tempering,the carbides(especially V-rich carbides)in Mg treatment obviously spheroidized and distributed uniformly and increased in quantity *** lath martensite size is reduced from 2.45 to 2.31μ*** suggests that magnesium treatment was able to yield smaller grains and more evenly distributed ***,the impact toughness,yield strength,and ultimate tensile strength of industrial H13 steel with magnesium treatment increased by 28%,65.5 MPa and 123.7 MPa,*** increment of strength mainly comes from dislocation strengthening,grain refinement strengthening,and precipitation strengthening,among which precipitation strengthening accounts for the largest proportion.

关键词： Industrial H13 steel Mg treatment Heat treatment Carbide-Mechanical property

Data-driven casting defect prediction model for sand casting based on random forest classification algorithm

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China Foundry 2024年第2期21卷 137-146页

作者： Bang Guan dong-hong Wang Da Shu Shou-qin Zhu Xiao-yuan Ji Bao-de Sun Shanghai Key Lab of Advanced High-Temperature Materials and Precision Forming School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China State Key Lab of Metal Matrix Composites Shanghai Jiao Tong UniversityShanghai 200240China Hefei Casting and Forging Factory of Anhui Heli Co. LtdHefei 230000China State Key Laboratory of Materials Processing and Die&Mould Technology Huazhong University of Science and TechnologyWuhan 430074China

The complex sand-casting process combined with the interactions between process parameters makes it difficult to control the casting quality,resulting in a high scrap rate.A strategy based on a data-driven model was proposed to reduce casting defects and improve production efficiency,which includes the random forest(RF)classification model,the feature importance analysis,and the process parameters optimization with Monte Carlo *** collected data includes four types of defects and corresponding process parameters were used to construct the RF *** results show a recall rate above 90% for all *** Gini Index was used to assess the importance of the process parameters in the formation of various defects in the RF ***,the classification model was applied to different production conditions for quality *** the case of process parameters optimization for gas porosity defects,this model serves as an experimental process in the Monte Carlo method to estimate a better temperature *** prediction model,when applied to the factory,greatly improved the efficiency of defect *** show that the scrap rate decreased from 10.16% to 6.68%.

关键词： sand casting process data-driven method classification model quality prediction feature importance

Effects of cooling rate on microstructure and microhardness of directionally solidified Galvalume alloy

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China Foundry 2024年第3期21卷 213-220页

作者： Ji-peng Li de-gao Qiao Jian Li Xiao-yang Luo Peng Peng Xian-tao Yan Xu-dong Zhang Gansu Jiu Steel Group Hongxing Iron and Steel Co. Ltd.Jiayuguan 735111GansuChina School of Materials and Energy Lanzhou UniversityLanzhou 730000China

The influences of cooling rate on the phase constitution,microstructural length scale,and microhardness of directionally solidified Galvalume(Zn-55Al-1.6Si)alloy were investigated by directional solidification experiments at different withdrawal speeds(5,10,20,50,100,200,and 400μm·s^(-1)).The results show that the microstructure of directionally solidified Galvalume alloys is composed of primary Al dendrites,Si-rich phase and(Zn-Al-Si)ternary eutectics at the withdrawal speed ranging from 5 to 400μm·s^(-1).As the withdrawal speed increases,the segregation of Si element intensifies,resulting in an increase in the area fraction of the Si-rich *** addition,the primary Al dendrites show significant refinement with an increase in the withdrawal *** relationship between the primary dendrite arm spacing(λ_(1))and the thermal parameters of solidification is obtained:λ_(1)=127.3V^(-0.31).Moreover,as the withdrawal speed increases from 5 to 400μm·s^(-1),the microhardness of the alloy increases from 90 HV to 151 *** is a combined effect of grain refinement and second-phase strengthening.

关键词： Galvalume alloy directional solidification microstructure length scale microhardness

Surface engineering of Li-and Mn-rich layered oxides for superior Li-ion battery

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Tungsten 2024年第1期6卷 259-268页

作者： Lu-Xiang Ma Tian-dong Chen Chun-Xi Hai Sheng-de dong Xin He Qi Xu Hang Feng AXin Ji-Tao Chen Yuan Zhou College of Materials and Chemistry and Chemical Engineering Chengdu University of TechnologyChendu 610000China Qinghai Building and Materials Research Co. LtdXining 810000China Beijing National Laboratory for Molecular Sciences College of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China

The Li-and Mn-rich layered oxides(R-LNCM)are considered as promising cathode materials for high-energy density lithium-ion batteries(LIBs).However,the interface side reaction aggravates the voltage and capacity fading between cathode material and electrolyte at high voltage,which severely hinders the practical application of LIB ***,lithium polyacrylate(LiPAA)as the binder and coating agent is applied to suppress the voltage and capacity fading of R-LNCM *** flexible LiPAA layers with high elasticity are capable of impeding cathode cracks on the particle surface via mechanical stress ***,superior voltage and capacity fading suppression on R-LNCM electrode is finally *** a result,LiPAA-R-LNCM cathode exhibits a remarkable specific capacity of 186 mA·h·g^(-1)with~73%retention at 1℃after ***,the corresponding average discharge potential is maintained to~3.1 V with only~0.4 V falling.

关键词： LiPAA interphase layer Interface side reaction Cathode cracks Capacity and voltage fading suppression Liand Mn-rich cathode

Resonance mechanism of flapping wing based on fluid structure interaction simulation

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Chinese Journal of Aeronautics 2024年第5期37卷 243-262页

作者： Yueyang GUO Wenqing YANG Yuanbo dong dong XUE National Key Laboratory of Science and Technology on Aerodynamic design and Research School of AeronauticsNorthwestern Polytechnical UniversityXi'an 710072China Research&development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen 518063China Yangtze River delta Research Institute of Northwestern Polytechnical University Taicang 215400China

Certain insect species have been observed to exploit the resonance mechanism of their *** order to achieve resonance and optimize aerodynamic performance,the conventional approach is to set the flapping frequency of flexible wings based on the Traditional Structural Modal(TSM)***,there exists controversy among researchers regarding the relationship between frequency and aerodynamic *** that the structural response of wings can be influenced by the surrounding air vibrations,an analysis known as Acoustic Structure Interaction Modal(ASIM)is introduced to calculate the resonant *** this study,Fluid Structure Interaction(FSI)simulations are employed to investigate the aerodynamic performance of flapping wings at modal frequencies derived from both TSM and ASIM *** performance is evaluated for various mass ratios and frequency ratios,and the findings indicate that the deformation and changes in vortex structure exhibit similarities at mass ratios that yield the highest aerodynamic ***,the flapping frequency associated with the maximum time-averaged vertical force coefficient at each mass ratio closely aligns with the ASIM frequency,as does the frequency corresponding to maximum ***,the ASIM analysis can provide an effective means for predicting the optimal flapping frequency for flexible ***,it enables the prediction that flexible wings with varying mass ratios will exhibit similar deformation and vortex structure *** paper offers a fresh perspective on the ongoing debate concerning the resonance mechanism of Flexible Flapping Wings(FFWs)and proposes an effective methodology for predicting their aerodynamic performance.

关键词： Flexible Flapping Wing(FFW) Acoustic Structure Interaction Modal(ASIM) Fluid Structure Interaction(FSI) Resonance mechanism Aerodynamic performance

Ultracycles consisting of macrocycles

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Chinese Chemical Letters 2024年第5期35卷 183-188页

作者： Wen-Hui Mi Teng-Yu Huang Yu-Fei Ao Xu-dong Wang Qi-Qiang Wang de-Xian Wang Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Molecular Recognition and FunctionInstitute of ChemistryChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Presented here is a one-pot strategy starting from rationally designed macrocyclic precursors for the diverse construction of sophisticated *** type and amount of the base were found to significantly influence the macrocyclization *** use of 4.0 *** resulted in ultracycles of both types A and B while the presence of CsF larger than 6.0 *** only type B *** of anion template increased the total yields and affected the distribution of the *** ultracycles can accommodate large organic dicarboxylates anions via multiple anion-πand hydrogen bonds,and show selectivity to the size-matched heptanedioate(C7^(2−)).Based on all possible species and relevant equilibrium constants as well as material and charge balances,a numerical iterative algorithm was developed and applied to fit the association constants of B2H with dicarboxylates from glutarate(C5^(2−))to octanedioate(C8^(2−)),which gave association constants up to 10^(3) L/mol.

关键词： Ultracycles Diversity-oriented synthesis Anion recognition Anion-πinteraction

Copper slag assisted coke reduction of phosphogypsum for sulphur dioxide preparation

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Chinese Journal of Chemical Engineering 2024年第1期65卷 43-53页

作者： dong Ma Qinhui Wang State Key Laboratory of Clean Energy Utilization Institute for Thermal Power EngineeringZhejiang UniversityHangzhou 310027China

The reduction of phosphogypsum(PG)to lime slag and SO_(2)using coke can effectively alleviate the environmental problems caused by ***,the PG decomposition temperature remains high and the product yield remains *** adding additives,the decomposition temperature can be further reduced and PG decomposition rate and product yield can be ***,the use of current additives such as Fe_(2)O_(3)and SiO_(2)brings the problem of increasing economic ***,it is proposed to use solid waste copper slag(CS)as a new additive to reduce PG to prepare SO2,which can reduce the cost and meet the environmental benefits at the same *** effects of proportion,temperature and thermostatic time on PG decomposition are investigated by experimental and kinetic analysis combined with FactSage thermodynamic calculations to optimize the roasting ***,the reaction mechanism is *** is found that adding CS to the coke and PG system can increase the rate of PG decomposition and SO_(2)yield while lowering the PG decomposition *** example,when the CS/PG mass ratio increases from 0 to 1,PG decomposition rate increases from 83.38%to 99.35%,SO_(2)yield increases from 78.62%to 96.81%,and PG decomposition temperature decreases from 992.4℃to 949.6℃.The optimal reaction parameters are CS/PG mass ratio of 1,Coke/PG mass ratio of 0.06 at 1100℃for 20 min with 99.35%PG decomposition rate and 96.81%SO_(2) *** process proceeds according to the following reactions:2CaSO_(4)+ 0.7C + 0.8Fe_(2)SiO_(4)→0.8Ca_(2)SiO_(4)+ 0.2Ca_(2)Fe_(2)O_(5)+ 0.4Fe_(3)O_(4)+2SO_(2)+ 0.7CO_(2)Finally,a process for decomposing PG with coke and CS is proposed.

关键词： Phosphogypsum Sulfur dioxide Copper slag Fluidized-bed Reduction Waste treatment