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Tuning the reactivity of Al-Ni by fine coating of halogen-containing energetic composites

Defence Technology（防务技术） 2022年第10期18卷 1810-1821页

作者： Su-lan Yang ke-juan meng Wu-xi Xie Hong-qi Nie Qi-Long Yan Science and Technology on Combustion Internal Flow and Thermo-Structure LaboratoryNorthwestern Polytechnical UniversityXi'an710072China b Xi'an Modern Chemistry Research Institute Xi'an710065China

In this paper,various core-shell structured Al—Ni@ECs composites have been prepared by a spray-drying *** involved ECs refer to the energetic composites(ECs)of ammonium perchlorate/nitrocellulose(AP/NC,NA)and polyvinylidene fluoride/hexanitrohexaazaisowurtzitane(PVDF/CL-20,PC).Two Al—Ni mixtures were prepared at atomic ratios of 1:1 and 1:3 and named as Al/Ni and Al/3Ni,*** thermal reactivity and combustion behaviors of Al—Ni@ECs composites have been comprehensively *** showed that the reactivity and combustion performance of Al—Ni could be enhanced by introducing both NA and PC energetic *** which the Al/Ni@NA composite exhibited higher reactivity and improved combustion *** measured flame propagation rate(v=20.6 mm/s),average combustion wave temperature(T_(max)=1567.0°C)and maximum temperature rise rate(γ_(t)=1633.6°C/s)of Al/Ni@NA are higher than that of the Al/Ni(v=15.8 mm/s,T_(max)=858.0°C,andγ_(t)=143.5°C/s).The enhancement in combustion properties could be due to presence of the acidic gaseous products from ECs,which could etch the Al_(2)O_(3)shell on the surface of Al particles,and make the inner active Al to be easier transported,so that an intimate and faster intermetallic reaction between Al and Ni would be ***,the morphologies and chemical compositions of the condensed combustion products(CCPs)of Al—Ni@ECs composites were found to be different depending on the types of *** compositions of CCPs are dominated with the Al—Ni intermetallics,combining with a trace amount of Al_(5)O_(6)N and Al_(2)O_(3).

关键词： Arrested high energy ball milling Intermetallic alloy Combustion performance Energetic composites Reactivity control

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Actively tunable electromagnetically induced transparency in hybrid Dirac-VO2 metamaterials

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Optoelectronics Letters 2025年第1期21卷 13-20页

作者： DI ke XIE meng XIA Huarong CHENG Anyu LIU Yu DU Jiajia Department of Optoelectronic Engineering Chongqing University of Post and Telecommunications Chongqing key Laboratory of Autonomous Navigation and Microsystem Chongqing University of Posts and Telecommunications Department of Automation Chongqing University of Post and Telecommunications

In this paper, we present a metamaterial structure of Dirac and vanadium dioxide（VO2） and investigate its optical properties using the finite-difference time-domain（FDTD） technique. Using the phase transition feature of VO2, the design can realize active tuning of the plasmon induced transparency（PIT） effect at terahertz frequency, thereby converting from a single PIT to a double-PIT. When VO2is in the insulating state, the structure is symmetric to obtain a single-band PIT effect. When VO2is in the metallic state, the structure turns asymmetric to realize a dual-band PIT effect. This design provides a reference direction for the design of actively tunable metamaterials. Additionally, it is discovered that the transparent window's resonant frequency and the Fermi level in this structure have a somewhat linear relationship. In addition, the structure achieves superior refractive index sensitivity in the terahertz band, surpassing 1 THz/RIU. Consequently, the design exhibits encouraging potential for application in refractive index sensors and optical switches.

关键词： Transparency

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POSITIVE PERIODIC SOLUTIONS OF PREDATOR-PREY SYSTEMS WITH INFINITE DELAY

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Chinese Annals of Mathematics,Series B 2000年第1期21卷 43-54页

作者： WANG ke FAN meng Department of Mathematics Northeast Normal University Changchun China

Conditions for existence of positive periodic solutions of nonautonomous, nonconvoluton type predator-prey system with infinite delay are given.

关键词： Positive periodic solutions Predator-prey system Infinite delay

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Elastic Low-Energy Electron Collisions with Methanethiol

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Chinese Journal of Chemical Physics 2015年第6期28卷 -页

作者： ke-dong Wang Ju meng Institute of Theoretical and Computational Chemistry Key Laboratory of Mesoscopic Chemistry of MOE School of Chemistry and Chemical Engineering Nanjing University Nanjing 210093 ChinaSchool of Physics and Electronical Engineering Henan Normal University Xinxiang 453007 China School of Physics and Electronical Engineering Henan Normal University Xinxiang 453007 China

We report ab initio scattering calculations results of electron-methanethiol collisions using R-matrix approach within the static-exchange and static-exchange-polarization approximations. The calculated elastic integral cross sections are in agreement with the experimental data. Two shape resonances of 2A′ symmetry located at 4.06 and 8.32 eV are detected within static-exchange-polarization model. For this dipole molecule, Born-closure procedure was used to account for the higher partial waves (l>4) for the convergence of the cross section. The effective collision frequencies over a wide electron temperature range (200–30000 K) are calculated using the data of the momentum-transfer cross section.

关键词： Elastic integral cross sections Differential cross section Shape resonance

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Conflict-free Incidence Coloring of Outer-1-planar Graphs

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Acta Mathematicae Applicatae Sinica 2024年第4期40卷 929-942页

作者： meng-ke QI Xin ZHANG School of Mathematics and Statistics Xidian UniversityXi’an 710071China

An incidence of a graph G is a vertex-edge pair(v,e)such that v is incidence with e.A conflict-free incidence coloring of a graph is a coloring of the incidences in such a way that two incidences(u,e)and(v,f)get distinct colors if and only if they conflict each other,i.e.,(i)u=v,(ii)uv is e or f,or(iii)there is a vertex w such that uw=e and vw=*** minimum number of colors used among all conflict-free incidence colorings of a graph is the conflict-free incidence chromatic number.A graph is outer-1-planar if it can be drawn in the plane so that vertices are on the outer-boundary and each edge is crossed at most *** this paper,we show that the conflict-free incidence chromatic number of an outer-1-planar graph with maximum degree△is either 2△or 2△+1 unless the graph is a cycle on three vertices,and moreover,all outer-1-planar graphs with conflict-free incidence chromatic number 2△or 2△+1 are completely *** efficient algorithm for constructing an optimal conflict-free incidence coloring of a connected outer-1-planar graph is given.

关键词： outer-1-planar graph incidence coloring combinatorial algorithm channel assignment problem

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Incidence Coloring of Outer-1-planar Graphs

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Acta Mathematicae Applicatae Sinica 2024年第3期40卷 840-848页

作者： meng-ke QI Xin ZHANG School of Mathematics and Statistics Xidian UniversityXi'an 710071China

A graph is outer-1-planar if it can be drawn in the plane so that all vertices lie on the outer-face and each edge crosses at most one another *** is known that every outer-1-planar graph is a planar *** this paper,we conjecture that every planar graph G has a proper incidence(Δ(G)+2)-coloring and confirm it for outer-1-planar graphs with maximum degree at least 8 or with girth at least ***,we prove that every outer-1-planar graph G has an incidence(Δ(G)+3,2)-coloring,and every outer-1-planar graph G with maximum degree at least 8 or with girth at least 4 has an incidence(Δ(G)+2,2)-coloring.

关键词： incidence coloring outer--planar graph planar graph

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Precise drag prediction of airfoil flows by a new algebraic model

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Acta Mechanica Sinica 2020年第1期36卷 35-43页

作者： meng-juan Xiao Zhen-Su She State key Laboratory for Turbulence and Complex Systems College of EngineeringPeking UniversityBeijing100871China

We report the results of accurate prediction of lift(C L)and drag(C D)coefficients of two typical airfoil flows(NACA0012 and RAE2822)by a new algebraic turbulence model,in which the eddy viscosity is specified by a stress length(SL)function predicted by structural ensemble dynamics(SED)*** accuracy of the prediction of C D with error of a few counts(one count is 10−4)and of C L with error under 1%-2%are uniformly obtained for varying angles of attack(AoA),indicating an order of magnitude improvement of drag prediction accuracy compared to currently used models(typically around 20 to 30 counts).More interestingly,the SED-SL model is distinguished with fewer parameters of clear physical meaning,which quantify underlying turbulent boundary layer(TBL)with a universal multi-layer structure,and is thus promising to be more easily generalizable to complex *** use of the new model for the calibration of flow condition in experiment and the extraction of flow physics from numerical simulation data of aeronautic flows are discussed.

关键词： Lift and drag coefficients Airfoil Flows Stress Length Structural ensemble dynamics

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Symmetry-based description of laminar-turbulent transition

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Science China(Physics,Mechanics & Astronomy) 2019年第9期62卷 79-85页

作者： meng-juan Xiao Zhen-Su She Department of Mechanics and Engineering Science and State key Laboratory for Turbulence and Complex Systems College of EngineeringPeking University

We report a simple but accurate description of flat plate transitional flow based on a structural ensemble dynamics(SED) theory of wall turbulence. It is postulated and verified by simulation data that a multi-layer stress length(SL) function ?12 presents a two-state structure in the streamwise x direction, characterizing the laminar-turbulent transition. The resulting algebraic model(called SED-SL) predicts correctly for the first time the entire streamwise profiles of the friction coefficient, Cf(x), of all seven sets of experimental(of e.g. T3 series) and simulations data of flat plate transitional flows, with varying incoming turbulence intensities Tu(or scales), superior to other closure models, with a two-state correlation for transition location Rex*= 3.3 × 10^6(1 +(Tu/0.65)^4)^-1.5/4. The extension to accurate description of transitional flows of engineering interests is discussed.

关键词： SED theory stress length multi-layer

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Survival analysis of a stochastic single-species population model with jumps in a polluted environment

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International Journal of Biomathematics 2016年第1期9卷 207-221页

作者： meng Liu ke Wang School of Mathematics and Statistics Northeast Normal University Jilin 130024 P. R. China School of Mathematical Science Huaiyin Normal University Huaian 223300 P. R. China Department of MathematicsHarbin Institute of Technology Weihai 264209 P. R. China

This paper is concerned with a stochastic single-species system with Levy jumps in a polluted environment. Some sufficient conditions on extinction, non-persistence in the mean, weak persistence in the mean, strong persistence in the mean, stability in the mean and stochastic permanence are obtained. The threshold between extinction and weak persistence in the mean is established. At the same time, under a simple condition, it is proved that this threshold also is the threshold between extinction and stability in the mean. The results reveal that L@vy jumps have significant effects to the persistence and extinction results.

关键词： Leay noise threshold Ito's formula.

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Effect of Nalmefene on Delayed Neurocognitive Recovery in Elderly Patients Undergoing Video-assisted Thoracic Surgery with One Lung Ventilation

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Current Medical Science 2020年第2期40卷 380-388页

作者： meng-yun LI Chao CHEN Zheng gang WANG Jian-juan ke Xiao-bo FENG Department of Anesthesiology Zhongnan HospitalWuhan UniversiryWuhan 430071China

The intravenous use of nalmefene has been found to exert neuroprotective effect in patients with severe traumatic brain injury and acute cerebral infarction;nonetheless,it is unknown whether nalmefene alleviates delayed neurocognitive *** purpose of the current research was to clarify the impact of nalmefene on delayed neurocognitive recovery in aged patients experiencing video-assisted thoracic surgery(VATS)with intraoperative use of one lung ventilation(OLV).The present study involved 120 paticents undergoing selective VATS,randomized to accept low-dose nalmefene(N1 group,n=40),high-dose nalmefene(N2 group,1n=40)or equal volume of physiologic saline(control group,1=40).A battery of neuropsychological tests were used to estimate cognitive function I day before surgery(o)and 10 days after surgery or before discharge(t).Regional cerebral oxygen saturation(rSO2)was detected 5 min before induction(t),5 min after induction(1),15 and 60 min after onset of OLV(62 and 13),and 15 min after termination of OLV(4).The plasma values of interleukin(IL)-1β,IL-6,tumor necrosis factor(TNF)-a1 and adiponectin(ADP)were also detected prior to induction of anesthesia(T0),1 h,2 h and 6 h after surgery(TI,T2,T3).On 1,delayed neurocognitive recovery occurred in 5/40(12.5%)patients of NI group,in 5/40(12.5%)patients of N2 group and in 13/40(32.5%)patients of control group(PNl group>control group(P<0.05).The result of our present research supports the hypothesis that the perioperative intravenous t

关键词： nalmefene one lung ventilation elderly patients delayed neurocognitive recovery perioperative neurocognitive disorders thoracic surgery

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