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A new look on the electric spark sensitivity of nitramines

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Defence Technology（防务技术） 2020年第1期16卷 10-17页

作者： Svatopluk Zeman ning liu Institute of Energetic Materials Faculty of Chemical TechnologyUniversity of PardubiceCZ-43210 PardubiceCzech Republic Xi'an Modern Chemistry Research Institute Xi'anShaanxi710065China

Electric spark energy,E_(ES),for a 50%probability of initiation of the 14 nitramines was determined using a measuring instrument in which the electrodes are in direct contact with the *** proportional relationships were established between the logarithm of the E_(ES)values and the length of the longest N-N bond in the nitramine *** finding is compatible with the mechanism of the first step in the electro-reduction of the nitramine *** proportional relationships were found to exist between the E_(ES)values and the crystal lattice free volumes,ΔV(*** increase in theΔV values increases the nitramine's resistance to electric sparks)but there were several nitramines with the opposite course of this *** a semilogarithic relationships between the E_(ES)values and a ratio of intrinsic volumes of molecule,V_(int),to theΔV values were described as well as ambiguous linear dependence between these energies and a sum of the positive and negative extremes of the molecular surface electrostatic potentials,V_(S,∑).Several nitramines studied(always the same ones)display roughly the same distribution in the coordinate systems of relationships with lengths of the longest N-N bonds,the Vint/ΔV ratio and the sum V_(S,∑)as the independent *** was found that,typically,such relationships start from a single identical point,in effect a point corresponding to data for a structural unit from which tho studied nitramines can be hypothetically generated,and/or are converging on another point,often the one corresponding to the data for *** the findings point to a fundamental influence of the intermolecular forces on reactivity of nitramines exposed to electric sparks.

关键词： Electric spark Free volume Initiation Nitramines Sensitivity

Influence of baffle position on liquid sloshing during braking and turning of a tank truck

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2010年第5期11卷 317-324页

作者： ning KANG Kui liu School of Transportation Science and Engineering University of A eronautics and Asttvnautics Beijing 100191 China

The influence of baffle position on liquid sloshing during the braking and turning of a tank truck was studied using a volume of fluid (VOF) model. The forces,their positions and weight distribution during braking and the forces and rolling moment during turning were calculated. The reliability of the calculation method was validated by comparisons with experimental results. The results showed that during braking,liquid splashes in the tank and the maximum forces and G (the ratio of weight acting on the front axle to the rear axle) are large when A (the ratio of the arch area above the baffle to the area of cross section)≤0.1. When A≥0.2,as the position of the baffle is lowered,the maximum of Fx (the force in direction x) first decreases then increases,and the maximum of Fy (the force in direction y) and G increase. During turning,liquid splashes in the tank and the maximum forces and M (the rolling moment) are large when D (the ratio of the arch area above the baffle to the area of cross section)≤0.2. When D≥0.3,as the position of the baffle is lowered,the maximums of Fy,Fz (the force in direction z) and M increase.

关键词： Tank truck Volume of fluid (VOF) method Liquid sloshing Two phase flow Baffle

Peridynamic modelling of impact damage in three-point bending beam with offset notch

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Applied Mathematics and Mechanics(English Edition) 2017年第1期38卷 99-110页

作者： ning liu Dahsin liu Wu ZHOU School of Mechanical Engineering Nanjing University of Science and Technology Department of Mechanical Engineering Michigan State University

The nonlocal peridynamic theory has been proven to be a promising method for the material failure and damage analyses in solid mechanics. Based upon the integro- differential equations, peridynamics enables predicting the complex fracture phenomena such as spontaneous crack nucleation and crack branching, curving, and arrest. In this paper, the bond-based peridynamic approach is used to study the impact damage in a beam with an offset notch, which is widely used to investigate the mixed I-II crack propagation in brittle materials. The predictions from the peridynamic analysis agree well with available experimental observations. The numerical results show that the dynamic fracture behaviors of the beam under the impact load, such as crack initiation, curving, and branching, rely on the location of the offset notch and the impact speed of the drop hammer.

关键词： peridynamics impact damage crack propagation fracture mode

Probing vector-like top partner from same-sign dilepton events at the LHC

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Communications in Theoretical Physics 2020年第10期72卷 80-86页

作者： Hang Zhou ning liu Physics Department and Institute of Theoretical Physics Nanjing Normal UniversityNanjing210023China

The standard model is a successful theory but is lacking a mechanism for neutrino mass generation as well as a solution to the naturalness *** the models that are proposed to simultaneously solve the two problems,heavy Majorana neutrinos and top partners are usually predicted to lead to a new decay mode of the top partner mediated by the heavy Majorana neutrinos:T→b W^+→b l^+l^+qq^*** this paper,we will study the observability of such a new signature via the pair production process of a top partner pp→TT→2 b+l^±l^±+4 j in a model independent *** performing Monte Carlo simulations,we present the 2σexclusion limits of the top partner mass and mixing parameters at the HL-LHC.

关键词： top quark partner LHC same sign leptons

Promoting effect of tantalum and antimony additives on deNOx performance of Ce3Ta3SbOx for NH3-SCR reaction and DRIFT studies

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Journal of Rare Earths 2018年第6期36卷 594-602页

作者： ning liu Jingyu Wang Fengying Wang Jun liu School of Environment and Safety Engineering North University of ChinaTaiyuan 030051China Key Laboratory of Coal Science and Technology Ministry of Education and Shanxi ProvinceTaiyuan University of TechnologyTaiyuan 030024China

A superior Ce-Ta-Sb composite oxide catalyst prepared using homogeneous precipitation method exhibited excellent deNOx efficiency and nearly 100% Nselectivity with broad operation temperature window and better resistance to higher space velocity, meanwhile strong resistance to HO and SO. This catalyst was systematically characterized using XRD, Nadsorption, SEM, TEM, XPS, ESR, Raman, H-TPR,NH3-TPD and in situ DRIFTS. There exists a synergistic effect between Ce, Ta and Sb species. It is further indicated that the prominent deNOx performance of the Ce3 Ta3 SbOx catalyst is attributed to the elevated Ce3+ concentrations, abundant active surface oxygen species, as well as surface acidity and reducibility,which is closely linked with the synergistic effect between Ce, Sb and Ta species. Results from DRIFTS reveal that the reaction mechanism of surface-adsorbed NH3 and NOspecies is linked to temperature,the L-H mechanism mainly occurs at low temperature(300 ℃). Overall,these findings indicate that Ce3 Ta3 SbOx is promising for NOpractical abatement.

关键词： Ce-Ta-Sb mixed oxides Homogeneous precipitation method NH_3-SCR Synergistic effect NO_x adsorbed species Rare earths

Sparse Representation Based Image Super-resolution Using Large Patches

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Chinese Journal of Electronics 2018年第4期27卷 813-820页

作者： liu ning ZHOU Pan liu Wenju KE Dengfeng National Laboratory of Pattern Recognition Institute of Automation Chinese Academy of Sciences Department of Electrical and Computer Engineering National University of Singapore

This paper addresses the problem of generating a high-resolution image from a low-resolution image. Many dictionary based methods have been proposed and have achieved great success in super resolution application. Most of these methods use small patches as dictionary atoms, and utilize a unified dictionary pair to conduct reconstruction for each patch, which may limit the super resolution performance. We use large patches instead of small ones to combine a dictionary and to conduct patch reconstruction. Since a large patch contains more meaningful information than a small one, the reconstruction result may have more high frequency details. To guarantee the completeness of the dictionary with large patch, the scale of the dictionary should be large as well. To handle the storage and calculation problems with large dictionaries,we adopt a binary encoding method. This method can preserve local information of patches. For each patch in the low-resolution image, we search its similar patches in the low-resolution dictionary to obtain a sub-dictionary. We compute its sparse representation to get the corresponding high-resolution version. Global reconstruction constraint is enforced to eliminate the discrepancy between the SR result and the ground truth. Experimental results demonstrate that our method outperforms other super resolution methods, especially when the magnification factor is large or the image is blurred by white Gaussian noise.

关键词： Super resolution Sparse representations Binary encoding

Numerical investigation of the dynamics of flexible vegetations in turbulent open-channel flows

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Journal of Hydrodynamics 2022年第4期34卷 681-699页

作者： Dong Xu Jia-ning liu Yun-feng Wu Chun-ning Ji State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300072China

Aquatic vegetations widely exist in natural rivers and play an essential role in the evolution of the water environment and ecosystem by changing the river’s hydrodynamic characteristics and transporting sediments and *** reality,most aquatic vegetations are highly flexible,which invalidates the“rigid-cylinder”assumption widely adopted in many *** explore the dynamics of submerged flexible vegetation in open-channel flows and its feedback to turbulent flow structures,numerical simulations are carried out using an in-house fluid-structure interaction(FSI)*** the simulations,the geometry of vegetation plants is grid-resolved,the turbulent flow is simulated using the large eddy simulation(LES),the dynamics of the flexible plants are solved using the vector form intrinsic finite element(VFIFE)method,and the turbulent flow and the plants are two-way coupled using the immersed boundary(IB)*** dynamic responses of the flexible vegetation with different plant flexibility,spacing,and submergence are *** results show that flexible plants are subjected to complex flow-induced vibrations(FIVs)rather than static *** FIV involves both streamwise and cross-flow motions driven by the small-scale vortex shedding around the plants and the large-scale Kelvin-Helmholtz(K-H)vortices developed in the vegetation canopy *** vegetations exhibit pulsive wave motion of different patterns in relatively long and narrow open *** with the open-channel flows with static plants with equivalent bending deformation,the dynamic responses of flexible plants may increase the turbulent Reynolds stress of the open-channel flow by 70%–100%and increase the invasion depth of the K-H vortices by 30%–50%.

关键词： Flexible vegetation dynamic responses flow-induced vibration(FIV) fluid-structure interaction(FSI)

Existence Results for Impulsive Neutral Stochastic Evolution Inclusions in Hilbert Space

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Acta Mathematica Sinica,English Series 2011年第7期27卷 1405-1418页

作者： Han Wen ning Bin liu School of Mathematics and Statistics Huazhong University of Science and Technology Wuhan 430074 P. R. China

This paper is concerned with the existence of mild solutions of a class of impulsive neutral stochastic evolution inclusions in Hilbert space in the case where the right hand side is convex or nonconvex-valued. The re... 详细信息

关键词： Impulsive mild solutions stochastic evolution inclusions convex nonconvex

Large Deviation for Supercritical Branching Processes with Immigration

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Acta Mathematica Sinica,English Series 2016年第8期32卷 893-900页

作者： Jing ning liu Mei ZHANG School of Mathematical Sciences Laboratory of Mathematics and Complex SystemsBeijing Normal University

In this paper, we study the large deviation for a supercritical branching process with immigration controlled by a sequence of non-negative integer-valued independently identical distributed random variables, improving the previous results for non immigration processes. We rely heavily on the detail description and limit property of the generating function of immigration processes.

关键词： Supercritical branching processes large deviation immigration