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Progress in Natural Science:Materials International 2022年第1期32卷 79-86页

作者： ch.Suresh Vidyasagar D.B.Karunakar Department of Architecture and Planning Indian Institute of Technology Roorkee Mechanical and Industrial Engineering Department Indian Institute of Technology Roorkee

This study reports the influence of sintering mechanism and reinforcement materials on the formation of ultra-fine and nanograins in Al-TiB-Y nanohybrid composites. The mechanical properties of the composites and their corresponding micro and nanostructures are correlated. The experimental and characterization results revealed that despite the addition of TiB, the hard and brittle AlTi phase formation in the composites was suppressed and hence, their ductility was retained. It was found that yttrium content of 0.3 wt% was the optimum amount which created advantageous spark plasma sintering conditions, and the addition of 0.3 wt% promoted the formation of bi-modal size grains（ultra-fine and nano） along with micro grains, Ω and other nano precipitates, resulting in a significant enhancement in the composite properties. The formation of ultra-fine and nanograins may be attributed to the combined effect of melting and rapid solidification at necking zones due to Joule’s heating and thermomechanical fatigue. Among all the sintered composites, the highest hardness（137 HV）, ultimate tensile strength（UTS）(496 MPa), yield strength（YS）(438 MPa) with 15.7% elongation were obtained in the sintered sample reinforced with 1.0 wt% TiBand 0.3 wt% yttrium.

关键词： Hybrid composites Ultra-fine grains Nano grains Spark plasma sintering Nano precipitates Microstructure

Mixed Convection Heat and Mass Transfer in a Micropolar Fluid with Soret and Dufour Effects

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Advances in Applied Mathematics and Mechanics 2011年第4期3卷 389-400页

作者： D.Srinivasacharya ch.RamReddy Department of Mathematics National Institute of TechnologyWarangal-506004Andhra PradeshIndia

A mathematical model for the steady,mixed convection heat and mass transfer along a semi-infinite vertical plate embedded in a micropolar fluid in the presence of Soret and Dufour effects is *** non-linear governing equations and their associated boundary conditions are initially cast into dimensionless forms using local similarity *** resulting system of equations is then solved numerically using the Keller-box *** numerical results are compared and found to be in good agreement with previously published results as special cases of the present *** non-dimensional velocity,microrotation,temperature and concentration profiles are displayed graphically for different values of coupling number,Soret and Dufour *** addition,the skin-friction coefficient,the Nusselt number and Sherwood number are shown in a tabular form.

关键词： Mixed convection heat and mass transfer micropolar fluid Soret and Dufour effects

Composite armor philosophy(CAP):Holistic design methodology of multi-layered composite protection systems for armored vehicles

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Defence Technology（防务技术） 2024年第11期41卷 181-197页

作者： Evangelos ch.Tsirogiannis Foivos Psarommatis Alexandros Prospathopoulos Georgios Savaidis EODH SA Research and Development Department63080LakkomaChalkidikisGreece SIRIUS Department of InformaticsUniversity of OsloGaustadalleen 23B0373OsloNorway Physical Metallurgy Laboratory(PML) Mechanical Engineering DepartmentAristotle University of Thessaloniki54124ThessalonikiGreece Centre for Research&Development of Advanced Materials(CERDAM) Center for Interdisciplinary Research and InnovationBalkan CenterBuilding B’10th km Thessaloniki-Thermi Road57001ThessalonikiGreece Laboratory of Machine Elements&Machine Design School of Mechanical EngineeringAristotle University of Thessaloniki54124ThessalonikiGreece Digital Representation and Additive Manufacturing(DRAM) Center for Interdisciplinary Research and InnovationBalkan CenterBuilding B’10th kmThessaloniki-Thermi Road57001ThessalonikiGreece

A philosophy for the design of novel,lightweight,multi-layered armor,referred to as Composite Armor Philosophy(CAP),which can adapt to the passive protection of light-,medium-,and heavy-armored vehicles,is presented in this *** can serve as a guiding principle to assist designers in comprehending the distinct roles fulfilled by each *** CAP proposal comprises four functional layers,organized in a suggested hierarchy of *** notable is the inclusion of a ceramic-composite principle,representing an advanced and innovative solution in the field of armor *** paper showcases real-world defense industry applications,offering case studies that demonstrate the effectiveness of this advanced *** represents a significant milestone in the history of passive protection,marking an evolutionary leap in the *** philosophical approach provides designers with a powerful toolset with which to enhance the protection capabilities of military vehicles,making them more resilient and better equipped to meet the challenges of modern warfare.

关键词： Passive armor protection Composite armor Ballistic performance Protection systems Vehicle protection Armor design

Sum-connectivity index of a graph

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Frontiers of Mathematics in china 2016年第1期11卷 47-54页

作者： Kinkar ch. DAS Sumana DAS Bo ZHOU Department of Mathematics Sungkyunkwan University Suwon 440-746 Korea School of Information and Communication Engineering Sungkyunkwan UniversitySuwon 440-746 Korea Department of Mathematics South China Normal University Guangzhou 510631 China

Let G be a simple connected graph, and let di be the degree of its i-th vertex. The sure,connectivity index of the graph G is defined as χ（G） =∑vivj∈E（G）（di＋dj）-1/*** discuss the effect onχ（G）of inserting... 详细信息

关键词： Graph Randid index sum-connectivity index minimum degree

Zagreb indices of graphs

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Frontiers of Mathematics in china 2015年第3期10卷 567-582页

作者： Kinkar ch. DAS Kexiang XU Junki NAM Department of Mathematics Sungkyunkwan University Suwon 440-746 Korea College of Science Nanjing University of Aeronautics & Astronautics Nanjing 210016China

The first Zagreb index M1 （G） is equal to the sum of squares of the degrees of the vertices, and the second Zagreb index M2 （G） is equal to the sum of the products of the degrees of pairs of adjacent vertices of the underlying molecular graph G. In this paper, we obtain lower and upper bounds on the first Zagreb index MI（G） of G in terms of the number of vertices （n）, number of edges （m）, maximum vertex degree （△）, and minimum vertex degree （δ）. Using this result, we find lower and upper bounds on M2（G）. Also, we present lower and upper bounds on M2（G）＋ M2（G） in terms of n, m, △, and δ, where denotes the complement of G. Moreover, we determine the bounds on first Zagreb coindex MI（G） and second Zagreb coindex M2（G）. Finally, we give a relation between the first Zagreb index and the second Zagreb index of graph G.

关键词： Graph first Zagreb index index inverse degree second Zagreb index Narumi-Katayama

Modeling Passengers Boarding in Aircraft Using Cellular Automata

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IEEE/CAA Journal of Automatica Sinica 2016年第4期3卷 365-384页

作者： Themistoklis Giitsidis Georgios ch.Sirakoulis IEEE Department of Electrical and Computer Engineering Democritus University of Thrace

Aircraft are profitable to their owners as long as they are in the air transporting passengers to their destinations;therefore it is vital to minimize as much as possible their preparation time on the *** this paper we simulate different boarding strategies with the help of a model based on cellular automata parallel computational tool,attempting to find the most efficient way to deliver each passenger to her/his assigned *** seat arrangements are used,a small one based on Airbus A320/ Boeing 737 and a larger one based on Airbus A380/ Boeing777-300.A wide variety of parameters,including time delay for luggage storing,the frequency by which the passengers enter the plane,different walking speeds of passengers depending on sex,age and height,and the possibility of walking past their seat,are simulated in order to achieve realistic results,as well as monitor their effects on boarding *** simulation results indicate that the boarding time can be significantly reduced by the simple grouping and prioritizing of *** accordance with previous papers and the examined strategies,the outside-in and reverse pyramid boarding methods outperform all the others for both the small and large airplane seat *** the latter,the examined strategies are introduced for first time in an analogous way to the initial small seat arrangement of Airbus A320/ Boeing737 aircraft ***,since in real world scenarios,the compliance of all the passengers to the suggested group division and boarding strategy cannot be guaranteed,further simulations were *** is clear that as the number of passengers disregarding the priority of the boarding groups increases,the time needed for the boarding to complete tends towards that of the random boarding strategy,thus minimizing the possible advantages gained by the proposed boarding strategies.

关键词： Cellular automata aircraft boarding modeling crowd dynamics

The Reading of a Painting

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中国翻译 2000年第3期 76-78页

作者： LiangShih-ch’iu

Direct oxidation of methane to oxygenates over heteropolyanions

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Journal of Natural Gas chemistry 2008年第3期17卷 309-312页

作者： Ouarda Benlounes Sadia Mansouri chérifa Rabia Smain Hocine Laboratoire de chimie Appliqueé et de Génie chimique Université Mouloud Mammeri Laboratoire de chimie du Gaz Naturel Institut de Chimie USTHB

Partial oxidation of methane to formaldehyde and methanol was studied at atmospheric pressure in the temperature range of 700-750 °C using heteropolycompound catalysts （NH4）6HSiMo11FeO40, （NH4）4PMo11FeO39, and H4PMo11VO40, which were prepared and characterized by various analysis techniques such as infrared, visible UV, XRD and DTA. O2 or N2O was used as the oxidizing agent, and the principal products of the reaction were ch3OH, ch2O, CO, CO2, and water. The conversion and the selectivity of products depend strongly on the reaction temperature, the nature of oxidizing agent, and the composition of catalyst.

关键词： methane oxidation heteropolycompounds methanol oxygenates

Kinetic Instability of Anisotropic Drift Wave Accompanied by Field Aligned Currents in Solar Coronal Loop

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Communications in Theoretical Physics 2018年第10期70卷 470-476页

作者： Hafsa Naim ch.Uzma G.Murtaza Salam chair Department of Physics GC University

Solar coronal loops are frequently accompanied by the field-aligned currents, which drive instabilities if the drift velocity u0 > v A the Alfv′en velocity. For our choice of parameters, the critical threshold value of u0/v A is ～ 3.0 for growth and the corresponding current filling factor ～ 10-3-10-4. Below this value we are no longer in the kinetic *** coronal loops also have short-scale density gradients within each loop. The electron resonance in the presence of density gradient causes the drift mode to grow. We study the effect of these two free energy sources, the electron drift and the density gradient, in the presence of temperature anisotropy T⊥_α > T∥_α. These effects simultaneously exist in the coronae. Using gyrokinetic theory, we investigate the influence of these effects, examine how they interplay with each other and study the consequent growth of the magnetosonic wave. We observe that kinetic instability driven by density gradient can be suppressed by field-aligned currents. The temperature anisotropy with chosen signatures causes further stabilizing effect. The results may prove useful to study the heating mechanism of solar coronal loops, acceleration of particles and confinement of particles in the thermonuclear reactors.

关键词： solar corona coronal loops temperature anisotropy density inhomogeneity field-aligned currents gyrokinetic

Dynamical downfolding for localized quantum states

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npj Computational Materials 2023年第1期9卷 1050-1058页

作者： Mariya Romanova Guorong Weng Arsineh Apelian Vojtěch Vlček Department of chemistry and Biochemistry University of CaliforniaSanta BarbaraCA 93106-9510USA Department of Materials University of CaliforniaSanta BarbaraCA 93106-9510USA

We introduce an approach to treat localized correlated electronic states in the otherwise weakly correlated host ***,the environment is dynamically downfolded on the correlated *** is captured via renormalization of one and two quasiparticle interaction terms which are evaluated using many-body perturbation *** outline the strategy on how to take the dynamical effects into account by going beyond the static limit ***,we introduce an efficient stochastic implementation that enables treating the host environment with a large number of electrons at a minimal computational *** a small explicitly correlated subspace,the dynamical effects are *** demonstrate the methodology by reproducing optical excitations in the negatively charged NV center defect in diamond,that agree with experimental results.

关键词： theory subspace states