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High strength and high ductility Mg-Gd-Y-Zn-Zr alloys obtained by controlling texture and dynamic precipitation through LPSO phase structure of different initial morphologies

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Journal of Rare Earths 2024年第12期42卷 2217-2230页

作者： Yayun He rui guo Xi Zhao Zhimin Zhang College of Mechanical and Electrical Engineering North University of China School of Aeronautics and Astronautics North University of China College of Materials Science and Engineering North University of China

This paper investigated the effects of three different initial phase structures on the microstructure evolution and tensile properties of extruded Mg-Gd-Y-Zn-Zr alloy, using an extrusion ratio of 3.6. These three initial phase structures were obtained by heat treatment, which is narrow spacing long-period stacking ordered phase(LPSO) phase structure alloy(EN alloy), wide spacing LPSO phase structure alloy(EW alloy), and narrow spacing LPSO phase and β phase overlapping phase structure alloy(EO alloy). The dynamic recrystallization(DRX) and dynamic precipitation behavior of extruded alloys with different initial structures, as well as their strengthening and ductility mechanisms were studied in detail. After hot extrusion with a low extrusion ratio, the alloy exhibits a bimodal structure composed of undynamic recrystallization(UN-DRX) grains and dynamic recrystallization(DRX) grains with strong textures. The narrow-spacing LPSO phase structure inhibits DRX and dynamic precipitation, while both the wide-spacing LPSO phase structure and the overlapping phase structure alloys promote DRX and dynamic precipitation. The strength improvement is mainly due to the strong texture and internal dislocation pinning of the undynamic recrystallization zone(UN-DRX) and the high strengthening effect of the narrow spacing LPSO phase. Although the promotion of DRX improves grain boundary strengthening effect, it cannot make up for reducing the UN-DRXed grain strengthening effect. A lower volume fraction of β dynamic precipitation phase is beneficial for improving the ductility of the alloy.

关键词： Mg-Gd-Y-Zn-Zr alloy Recrystallization behavior Mechanical property Rare earths

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BEESO:Multi-strategy Boosted Snake-Inspired Optimizer for Engineering Applications

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Journal of Bionic Engineering 2023年第4期20卷 1791-1827页

作者： Gang Hu rui Yang Muhammad Abbas guo Wei Department of Applied Mathematics Xi’an University of TechnologyXi’an710054China School of Computer Science and Engineering Xi’an University of TechnologyXi’an710048China Department of Mathematics University of SargodhaSargodha40100Pakistan University of North Carolina at Pembroke PembrokeNC28372USA

This paper presents an efficient enhanced snake optimizer termed BEESO for global optimization and engineering *** a newly mooted meta-heuristic algorithm,snake optimizer(SO)mathematically models the mating characteristics of snakes to find the optimal *** has a simple structure and offers a delicate balance between exploitation and ***,it also has some shortcomings to be *** proposed BEESO consequently aims to lighten the issues of lack of population diversity,convergence slowness,and the tendency to be stuck in local optima in *** presentation of Bi-Directional Search(BDS)is to approach the global optimal value along the direction guided by the best and the worst individuals,which makes the convergence speed *** increase in population diversity in BEESO benefits from Modified Evolutionary Population Dynamics(MEPD),and the replacement of poorer quality individuals improves population *** Elite Opposition-Based Learning(EOBL)provides improved local exploitation ability of BEESO by utilizing solid solutions with good *** performance of BEESO is illustrated by comparing its experimental results with several algorithms on benchmark functions and engineering ***,the results of the experiment are analyzed again from a statistical point of view using the Friedman and Wilcoxon rank sum *** findings show that these introduced strategies provide some improvements in the performance of SO,and the accuracy and stability of the optimization results provided by the proposed BEESO are competitive among all *** conclude,the proposed BEESO offers a good alternative to solving optimization issues.

关键词： Snake optimizer Bi-Directional Search Evolutionary Population Dynamics Elite Opposition-Based Learning Strategy Mechanical optimization design

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A mathematical model of combined therapies against cancer using viruses and inhibitors

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Science China Mathematics 2008年第12期51卷 2315-2329页

作者： TAO YouShan guo qian Department of Applied Mathematics Dong Hua UniversityShanghai 200051China Department of Mathematics Shanghai Normal UniversityShanghai 200234China

This paper deals with a procedure for combined therapies against cancer using oncolytic viruses and inhibitors. Replicating genetically modified adenoviruses infect cancer cells, reproduce inside them and eventually cause their death (lysis). As infected cells die, the viruses inside them are released and then proceed to infect other tumor cells. The successful entry of virus into cancer cells is related to the presence of the coxsackie-adenovirus receptor (CAR). Mitogen-activated protein kinase kinase (known as MEK) inhibitors can promote CAR expression, resulting in enhanced adenovirus entry into cancer cells. However, MEK inhibitors can also cause G1 cell-cycle arrest, inhibiting reproduction of the virus. To design an effective synergistic therapy, the promotion of virus infection must be optimally balanced with inhibition of virus production. We introduce a mathematical model to describe the effects of MEK inhibitors and viruses on tumor cells, and use it to explore the reduction of the tumor size that can be achieved by the combined therapies. Furthermore, we find an optimal dose of inhibitor: Poptimal = 1 - μ/δ for a certain initial density of cells (where μ is the removal rate of the dead cells and δ is the death rate of the infected cells). The optimal timing of MEK inhibitors is also numerically studied.

关键词： tumors oncolytic viruses MEK inhibitors mathematical modeling 35Q80 35R35 92A15 92C50

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Rheological and DSC Studies on the Interaction between κ-Carrageenan and Cellulose Nanocrystals (CNC)

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Chinese Chemical Letters 2006年第5期17卷 695-698页

作者： rui guo En Yong DING Key Laboratory of Cellulose and Lignocellulosics Chemistry Guangzhou Institute of Chemistry Chinese Academy of Sciences Guangzhou 510650 Graduate School of the Chinese Academy of Sciences Beijing 100039

Rheometer and differential scanning calorimetry （DSC） have been used to probe the mechanism of gelation in gels formed by mixture of k-carrageenan and cellulose nanocrystals （CNC）. The results indicated that an as... 详细信息

关键词： Rheology DSC r-carrageenan cellulose nanocrystals (CNC).

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Bounds on partial derivatives of NURBS surfaces

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Applied Mathematics(A Journal of Chinese Universities) 2017年第3期32卷 281-293页

作者： WANG guo-jin XU Hui-xia HU qian-qian School of Mathematical Sciences Zhejiang University Institute of Mathematics Zhejiang Wanli University Department of Mathematics Zhejiang Gongshang University

In this paper, we estimate the partial derivative bounds for Non-Uniform Rational B-spline(NURBS) surfaces. Firstly, based on the formula of translating the product into sum of B-spline functions, discrete B-spline theory and Dir function, some derivative bounds on NURBS curves are provided. Then, the derivative bounds on the magnitudes of NURBS surfaces are proposed by regarding a rational surface as the locus of a rational curve. Finally, some numerical examples are provided to elucidate how tight the bounds are.

关键词： NURBS curve NURBS surface derivative bound Dir function discrete B-spline

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Accurate and efficient follower log repair for Raft-replicated database systems

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Frontiers of Computer Science 2021年第2期15卷 91-103页

作者： Jinwei guo Peng CAI Weining qian Aoying ZHOU School of Data Science and Engineering East China Normal UniversityShanghai200062China

State machine replication has been widely used in modern cluster-based database *** commonly deployed configurations adopt the Raft-like consensus protocol,which has a single strong leader which replicates the log to other *** the followers can handle read requests and many real workloads are usually read-intensive,the recovery speed of a crashed follower may significantly impact on the *** from traditional database recovery,the recovering follower needs to repair its local log *** Raft protocol takes many network round trips to do log comparison between leader and the crashed *** reduce network round trips,an optimization method is to truncate the follower’s uncertain log entries behind the latest local commit point,and then to directly fetch all committed log entries from the leader in one round ***,if the commit point is not persisted,the recovering follower has to get the whole log from the *** this paper,we propose an accurate and efficient log repair(AELR)algorithm for follower *** is more robust and resilient to follower failure,and it only needs one network round trip to fetch the least number of log entries for follower *** approach is implemented in the open source database system *** experimentally show that the system adopting AELR has a good performance in terms of recovery time.

关键词： Raft high availability log replication log repair

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Hot Deformation Mechanism and Ring Rolling Behavior of Powder Metallurgy Ti_2AlNb Intermetallics

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Acta Metallurgica Sinica(English Letters) 2017年第7期30卷 621-629页

作者： Zheng-Guan Lu Jie Wu rui-Peng guo Lei Xu rui Yang Institute of Metal Research Chinese Academy of Sciences School of Materials Science and Engineering University of Science and Technology of China School of Materials Science and Engineering Northeastern University

Powder metallurgy（PM） Ti–22Al–24Nb–0.5Mo（at.%） alloys were prepared by hot isostatic pressing. In order to study the feasibility of PM ＋ ring rolling combined process for preparing Ti_2AlNb rings, thermal mechanical simulation tests of PM Ti_2AlNb alloys were conducted and two rectangular PM rings（150 mm in height, 75 mm in thickness,350 mm in external diameter） were rolled as a validation experiment. Experimental results show that the flow stress of Ti_2AlNb alloys exhibited a significant drop at the very beginning of the deformation（true strain／0.1）, and became stable with the increase in strain. Stress instability phenomenon of PM Ti_2AlNb alloys was more obvious than that of wrought alloy. Flow stress fluctuation at the initial stage of deformation is related to phase transition of Ti_2AlNb alloys which strongly depends on heat treatment and thermal mechanical deformation process. Processing windows during initial stage of ring rolling process is very crucial. A sound PM Ti_2AlNb rectangular ring blank（height = 150 mm, thickness = 30 mm, external diameter = 750 mm） was successfully rolled in two passes by using the improved heat preservation method and optimized rolling parameters. Tensile properties of PM Ti_2AlNb alloy were improved, and the porosity was reduced after ring rolling.

关键词： Ti_2AlNb alloy Powder metallurgy Hot deformation Ring rolling

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Ultrasound-assisted Extraction of Kamebakaurin from Rabdosia excisa by Response Surface Methodology

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Chemical Research in Chinese Universities 2013年第6期29卷 1072-1077页

作者： TANG Jian MA rui-li LI qian-qian JIANG Chun-bao CHEN rui OUYANG Zhen CHEN Hai-sheng School of Pharmacy Jiangsu University Zhenjiang 212013 P.R.China School of Pharmacy Second Ministry Medical University Shanghai 200433 R R. China College of Material Chemistry and Chemical Engineering Hangzhou Normal University Hangzhou 310036 P. R. China

For the efficient extraction of kamebakaurin（KA）, the ultrasound-assisted extraction（UAE） of KA from Rabdosia excisa（R, excisa） via response surface methodology（RSM） was investigated with high-performance liquid chromatography（HPLC）. Effects of the experimental parameters such as extraction solvent, ratio of liquid to plant material, extraction time and extraction temperature on the extracting efficiency of KA from R. excisa were evaluated, and the purity of KA in residual was calculated. The optimized conditions were 65.5%（volume fraction） acetone, 35 ℃, time of 24.6 min with ultrasound of 80 W/L, 40 kHz, ratio of liquid to plant material at 30：1（mL/g）. The maximum yield of KA is 0.708 mg/kg, with mean purity of 6.09%, indicating that ultrasound-assisted extraction is a feasible and useful method for extracting KA from R. excisa.

关键词： Ultrasound-assisted extraction Kamebakaurin Rabdosia excisa Response surface methodology

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A Review and Prospects on Collaborative Ontology Editing Tools

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Journal of Integrative Agriculture 2012年第5期11卷 731-740页

作者： XIAN guo-jian ZHAO rui-xue Agricultural Information Institution Chinese Academy of Agricultural SciencesBeijing 10008lPR.China

Building ontology is a fundamental but also hard work. Collaborative ontology editing tools can make ontology development more efficiently. In this paper, the important features of collaborative ontology development were analyzed, and several tools such as AGROVOC Concept Server Workbench （ACSW）, Collaborative Prot6g6 and WebProt6g6 were studied. Besides, some comparisons among them from several aspects were made and some prospects for the further improvement of these tools were given. Finally, we show it is a good way to build agricultural ontology with these tools collaboratively and simultaneously.

关键词： collaborative ontology editing agricultural ontology ACSW Collaborative Prot6g6 WebProt6g6

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Global attractor for Hirota equation

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Applied Mathematics(A Journal of Chinese Universities) 2008年第1期23卷 57-64页

作者： ZHANG rui-feng guo Bo-ling Institute of Appl. Math. College of Math. and Inform. Sci. Henan Univ. Kaifeng 475001 China. Institute of Appl. Phys. and Comput. Math. Beijing 100088 China.

The long time behavior of solution for Hirota equation with zero order dissipation is studied. The global weak attractor for this system in Hper^k is constructed. And then by exact analysis of the energy equation, it ... 详细信息

关键词： Hirota equation a priori estimate global attractor.

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