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Using a Gaussian mathematical model to define eruptive stages of young volcanic rocks in Tengchong based on laser 40Ar/39Ar dating

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Science China Earth Sciences 2020年第5期63卷 662-673页

作者： Xinwei ZHAO jing ZHOU Fang ma jianqing ji Alan DEINO School of Earth Sciences and Resources China University of GeosciencesBeijing 100083China Key Laboratory of Orogenic Belts and Crustal Evolution School of Earth and Space SciencesPeking UniversityBeijing 100871China Berkeley Geochronology Center Berkeley CA94709USA

Reconstruction of Quaternary environments,late Cenozoic geodynamics and evaluation of volcanic hazards,all depend on the precise delineation of eruptive *** recent years,laser 40Ar/39Ar dating methods have been widely used for dating young volcanic rocks,given their stable automated testing process,very low background level and high sensitivity,which meet the requirements for precise dating of young *** paper applied high-precision laser 40Ar/39Ar dating to the main volcanic units in the Tengchong area and obtained ages in the range of 0.025–5.1 ma using conventional data processing ***,conventional dating highlighted issues related to very low radiogenic 40Ar content,accidental errors and poor data stability,which led to huge age ***,lacking a unified timescale,conventional methods were unable to strictly define the stages of the Tengchong volcanic eruptions,leading to ongoing *** this study,we applied a Gaussian mathematical model to deal with all 378 original ages from 13 *** apparent age-probability diagram,consisting of three independent waveforms,have been *** corresponding isochron ages of these three waveforms suggest there were three volcanic eruptive stages,namely during the Pliocene(3.78±0.04 ma),early Middle Pleistocene(0.63±0.03 ma)and late Middle Pleistocene to early Late Pleistocene(0.139±0.005 ma).These results accurately define eruptive stages in the Tengchong area.

关键词： Laser 40Ar/39Ar dating Gaussian mathematical model Eruptive stages Apparent age-probability diagram Age deviations Isochron age

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The simultaneous improvements of strength and ductility in additive manufactured Ni-based superalloy via controlling cellular subgrain microstructure

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Journal of materials Science & Technology 2021年第9期68卷 184-190页

作者： Yanan Zhao Zongqing ma Liming Yu ji Dong Yongchang Liu State Key Lab of Hydraulic Engineering Simulation and Safety.School of materials Science and Engineering Tianjin UniversityTianjin 300072China Tianjin Sino-German University of Applied Sciences TianjinChina

Fine cellular subgrain structure was formed in the Selective Laser Melting(SLM) manu factured IN718 alloy via optimizing the processing *** the subsequent homogenization heat treatment process,the Laves phase dispersed at the subgrain boundaries can be eliminated while the cellular subgrain structure is reserved in the printed samples after holding at 1080℃ for 50 *** the prolongation of the holding time,the subgrain boundaries undergo low angle rotation via the motion ofdislocation,which leads to the annihilation of the cellular subgrain ***,during the subsequent double aging heat treatment process,the reserved cellular subgrain structure in the homogenized samples promotes the precipitation of γ" second phase nanoparticles,and these precipitated γ" phase nanoparticles prefer to distribute at subgrain *** was found that these unique subgrain boundaries with γ" phase precipitates can hinder but not fully terminate the motion of dislocation during the plastic deformation process,which contributes to increasing the strength as well as holding the stable plastic ***,the strength and ductility of final prepared IN718 alloy with cellular subgrain microstructure were improved simultaneously compared to the prepared alloy without cellular subgrain structure,which even exceed the mechanical properties standards(AMS 5662) of wrought IN718 *** results in our work suggest that controlling the subgrain structure is a promising effective strategy to improve the mechanical properties of SLM manu factured nickel-based superalloy.

关键词： Selective laser melting Superalloy Subgrain structure Strengthening and toughening

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Effects of the Wetting Particles on Phase Separation of Binary Mixtures

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Chinese Physics Letters 2000年第11期17卷 824-826页

作者： LIU ji-Wen ma Yu-Qiang National Laboratory of Solid State Microstructures Nanjing UniversityNanjing 210093

We study phase separation of binary mixtures in the presence of mobile particles by the lattice Monte Carlo *** presence of mobile particles changes the morphology of the domain growth,in agreement with earlier experimental *** varying the wetting interaction strength,we can control the speed of phase separation,and find a critical wetting strength beyond which the growth of the domains slows *** propose a novel scaling function which describes the growth of the domain size L(t)as a function of *** suggests an applicable way to tune the speed of phase separation by the coupling between the phase decomposition and the mobile particle-wetting process.

关键词： strength separation phase

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Wong-Zakai approximations and long term behavior of stochastic FitzHugh-Nagumo system

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International Journal of Biomathematics 2021年第3期14卷 23-52页

作者： Ling Qin Dandan ma ji Shu School of mathematics Science Laurent mathematics Center and V.C.&V.R.Key Lab Sichuan Normal University Chengdu 610066P.R.China

This paper is concerned with the Wong-Zakai approximations given by a stationary process via the Wiener shift and their associated long term behavior of stochastic FitzHugh-Nagumo system driven by white *** prove the existence and uniqueness of pullback random attractors for the approximate system under much weaker conditions than the original *** the system is driven by additive white noise,we also prove the convergence of solutions of Wong-Zakai approximations and the upper semicontinuity of random attractors of the approximate random system as the size of approximation approaches zero.

关键词： Wong-Zakai approximation random attractor FitzHugh-Nagumo system upper semicontinuity white noise

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A Novel Defender-Attacker-Defender Model for Resilient Distributed Generator Planning with Network Reconfiguration and Demand Response

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Energy Engineering 2024年第5期121卷 1223-1243页

作者： Wenlu ji Teng Tu Nan ma Nanjing Power Supply Company State Grid Jiangsu Electric Power Co.Ltd.Nanjing210019China

To improve the resilience of a distribution system against extreme weather,a fuel-based distributed generator(DG)allocation model is proposed in this *** this model,the DGs are placed at the planning *** an extreme event occurs,the controllable generators form temporary microgrids(MGs)to restore the load ***,a demand response program(DRP)mitigates the imbalance between the power supply and demand during extreme *** cope with the fault uncertainty,a robust optimization(RO)method is applied to reduce the long-term investment and short-term operation *** optimization is formulated as a tri-level defenderattacker-defender(DAD)*** the first level,decision-makers work out the DG allocation scheme;at the second level,the attacker finds the optimal attack strategy with maximum damage;and at the third level,restoration measures,namely distribution network reconfiguration(DNR)and demand response are *** problem is solved by the nested column and constraint generation(NC&CG)method and the model is validated using an IEEE 33-node *** studies validate the effectiveness and superiority of the proposed model according to the enhanced resilience and reduced cost.

关键词： Distribution system resilience defender-attacker-defender distributed generator demand response microgrids formation

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THE OPTIMIZATION OF THE HULL FORM WITH THE MINIMUM WAVE maKING RESISTANCE BASED ON RANKINE SOURCE METHOD

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Journal of Hydrodynamics 2009年第2期21卷 277-284页

作者： ZHANG Bao-ji ma Kun ji Zhuo-shang State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology Dalian116024 China Ship CAD Engineering Center Dalian University of Technology Dalian 116024 China

The hull form optimization concerns one of the most important applications of wave making resistance theories. In order to obtain a hull form with the minimum wave making resistance, an optimization design method based on the CFD is proposed, which combines the Rankine source method with the nonlinear programming （NLP）. The bow-body shape is optimized with the minimum wave making resistance as the objective function. A hull form modification function is introduced to represent an improved hull surface, which can be used to generate a new smooth hull surface by multiplying it by the offset data of the original hull surface. The parameters of the hull form modification function are taken as the design variables. Other constraint conditions can also be considered, for example, in optimizing the lines of the bow, appropriate displacements can be taken as the basic constraints. S60 hull form is selected as the original hull. Three improved hulls are obtained by optimal design. Rankine source method proves to be an effective method in ship form optimization based on analysis of the resistance performance and lines of the improved hull.

关键词： Rankine source method CFD NLP optimization method,wave making resistance

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Non-interference topology scheme in wireless sensor networks

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The Journal of China Universities of Posts and Telecommunications 2007年第2期14卷 7-13页

作者： ma Shu-hui ji Hong YUE Guang-xin School of Telecommunication Engineering Beijing University of Posts and Telecommunications Beijing 100876 China

A novel topology scheme, cell with multiple mobile sinks method （CMMSM）, is proposed in this article for the collection of information and for the environment monitoring in wireless sensor networks. The system consists of many static sensors, scattered in a large scale sensing field and multiple mobile sinks, cruising among the clusters. Conservation of energy and simplification of protocol are important design considerations in this scheme. The noninterference topology scheme largely simplifies the full-distributed communication protocol with the ability of collision avoidance and random routing. The total number of cluster heads in such a topology was analyzed, and then an approximate evaluation of the total energy consumption in one round was carded out. Simulation results show that CMMSM can save considerable energy and obtain higher throughput than low-energy adaptive clustering hierarchy （LEACH） and geographical adaptive fidelity （GAF）.

关键词： sensor networks energy consumption topology design multiple mobile sinks

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Neighbor Sum Distinguishing Total Colorings of Triangle Free Planar Graphs

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Acta mathematica Sinica,English Series 2015年第2期31卷 216-224页

作者： ji Hui WANG Qiao Ling ma Xue HAN School of mathematical Sciences University of Ji'nan

A total k-coloring c of a graph G is a proper total coloring c of G using colors of the set [k] = {1, 2,...,k}. Let f（u） denote the sum of the color on a vertex u and colors on all the edges incident to u. A k-neighbor sum distinguishing total coloring of G is a total k-coloring of G such that for each edge uv ∈ E（G）, f（u） ≠ f（v）. By X＂nsd（G）, we denote the smallest value k in such a coloring of G. Pilgniak and Wozniak conjectured that X＂nsd（G） ≤ △（G）＋ 3 for any simple graph with maximum degree △（G）. In this paper, by using the famous Combinatorial Nullstellensatz, we prove that the conjecture holds for any triangle free planar graph with maximum degree at least 7.

关键词： Neighbor sum distinguishing total coloring combinatorial Nullstellensatz triangle freeplanar graph

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Embryonic Growth and Yolk Depletion during Incubation in the Chinese Skink, Plestiodon chinensis

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Asian Herpetological Research 2019年第1期10卷 56-61页

作者： Li ma Kun GUO Shan SU Xiang ji jiangsu Key Laboratory for Biodiversity and Biotechnology College of Life Sciences Nanjing Normal University

We collected 24 gravid female Chinese skinks(Plestiodon chinensis) to study embryonic growth and yolk depletion during incubation. Females laid eggs between late may and mid-June. Eggs were incubated at 24(± 0.3) ℃. One egg from each clutch was dissected at 5-d intervals starting at laying. Embryonic stages at laying varied from Dufaure and Hubert's(1961) Stage 30-35, with a mean stage of 32.6. Incubation lengths at 24 ℃ varied from 35.1 to 48.3 d, with a mean of 41.5 d. Based on the derived functions describing instantaneous changes in embryo dry mass and yolk dry mass, we identified three phases of embryonic growth or yolk depletion in P. chinensis. Phase 1, from Day 0(at laying) to Day 15(～36% of the way through incubation), was one of minimal transfer of material from yolk to embryo. Phase 2, from Day 15 to Day 32-33(～77%-80% of the way through incubation), was characterized by increasingly rapid embryonic growth or yolk depletion. Phase 3, from Day 32-33 to hatching, was characterized by reduced embryonic growth or yolk depletion. The length of the last embryonic stage(Stage 40 = completely differentiated embryos) accounted for about 28% of incubation length, and the dry mass of the smallest embryos of Stage 40 accounted for only ～48% of the hatchling dry mass. Our study adds evidence to the idea that oviposition is not timed to coincide with the onset of rapid embryonic growth in oviparous reptiles, and is first to demonstrate that ～50% embryonic growth occurs in the last quarter of incubation in P. chinensis.

关键词： egg incubation embryonic growth embryonic stage Plestiodon chinensis scincid lizard yolk depletion

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Comparative Study of Convective Heat Transfer Performance of Steam and Air Flow in Rib Roughened Channels

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Journal of Thermal Science 2018年第2期27卷 184-194页

作者： ma Chao ji Yongbin GE Bing ZANG Shusheng CHEN Hua marine engineering college Dalian Maritime University School of Mechanical Engineering Shanghai Jiao Tong University

A comparative experimental study of heat transfer characteristics of steam and air flow in rectangular channels roughened with parallel ribs was conducted by using an infrared camera. Effects of Reynolds numbers and rib angles on the steam and air convective heat transfer have been obtained and compared with each other for the Reynolds number from about 4,000 to 15,000. For all the ribbed channels the rib pitch to height ratio(p/e) is 10, and the rib height to the channel hydraulic diameter ratio is 0.078, while the rib angles are varied from 90° to 45°.Based on experimental results, it can be found that, even though the heat transfer distributions of steam and air flow in the ribbed channels are similar to each other, the steam flow can obtain higher convective heat transfer enhancement capability, and the heat transfer enhancement of both the steam and air becomes greater with the rib angle deceasing from 90° to 45°. At Reynolds number of about 12,000, the area-averaged Nusselt numbers of the steam flow is about 13.9%, 14.2%, 19.9% and 23.9% higher than those of the air flow for the rib angles of 90°,75°, 60° and 45° respectively. With the experimental results the correlations for Nusselt number in terms of Reynolds number and rib angle for the steam and air flow in the ribbed channels were developed respectively.

关键词： steam cooling air cooling rib-roughened channel gas turbine heat transfer

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