检索结果-南通市图书馆

Experimental study on ceramic balls impact composite armor

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2020年第2期16卷 408-416页

作者： Wei-zhan Wang Zhi-gang Chen shun-shan Feng Tai-yong Zhao Underground Target Damage Technology National Defense Key Discipline Laboratory North University of ChinaTaiyuan 030051ShanxiChina State Key Laboratory of Explosion Science and Technology Beijing Institute of Technology100081BeijingChina

Ceramic balls represent a new type of damaging element,and studies on their damaging power of composite armor are required for a comprehensive evaluation of the effectiveness of various types of *** goal of this study was to determine the impact ofφ7 mm toughened Al2 O3 ceramic balls on a composite ceramic/metal *** influences of the ceramic panel and the thickness of the metal backing material on the destroying power of the ceramic balls were first *** on the agreement between numerical simulation,experimental results,and calculation models of the target plate resistance,the response mechanism of the ceramic balls was further *** results indicate that for a back plate of Q235 steel,with an increasing thickness of the ceramic panel,the piercing speed limit of the ceramic balls gradually increases and the diameter of the out-going hole on the metal back *** conditions were tested to assess the effects on the piercing speed,the diameter of the out-going hole,the micro-element stress,and the integrity of the recovered ceramic bowl.

关键词： Impact Penetration Infinitesimal Interface collapse

Light Flavor Vector and Pseudo Vector Mesons from a Light-Cone QCD Inspired Effective Hamiltonian Model with SU（3） Flavor Mixing Interactions

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2010年第6期27卷 37-39页

作者： GUO xiao-Bo TAO Jun LI Lei WANG shun-Jin Center of Theoretical Physics School of Physics and Technology Sichuan University Chengdu 610064 School of Science Southwest University of Science and Technology Mianyang 621010 Center of Theoretical Nuclear Physics National Laboratory of Heavy Ion Accelerator Lanzhou 730000

Based on the light-cone effective Hamiltonian with confining potential and SU （3） flavor mixing interactions, the flavor mixing mesons on the u, d, and s quark sectors are investigated. The mass eigen equations of the flavor mixing vector and pseudo vector mesons are solved. The calculated masses are in good agreement with the experimental data.

关键词： Vectors Weight Mixing Flavour

Effect of Indirect Transformation of Retained Austenite During Tempering on the Charpy Impact Toughness of a Low-Alloy Cr-Mo-V Steel

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2020年第10期33卷 1346-1358页

作者： yong-Han Li Zhong-Hua Jiang Zhen-Dan Yang Jue-shun Zhu Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences72 Wenhua RoadShenyang 110016China

A modified tempering treatment has been designed in order to avoid the direct transformation of retained austenite(Ar)during tempering of a low-alloy Cr-Mo-V *** of the direct transformation of Ar into ferrite and M23C6 carbides during conventional tempering at 700℃,transformation into aggregate of ferrite and cementite has been forced by a pre-tempering at 455℃ before conventional *** have been performed on specimens quenched with cooling rates 1.5,3 and 12℃/s,providing different types of Ar within the as-quenched *** results show that the tempering modification does not improve the Charpy impact toughness at the highest quenching rate of 12℃/s,where the specimens cannot incur cleavage cracking induced from fine and discontinuous M23C6 carbides along lath *** the lowest quenching rate 1.5℃/s,the Charpy impact toughness can be improved,and the failure is dominated by carbide aggregates,which originate from the decomposed products of blocky *** is because the tempering modification effectively suppresses the formation of coarse M23C6 carbides at interfaces between the carbide aggregate and bainitic matrix,thereby resulting in a relatively homogeneous distribution of M23C6 carbides inside carbide ***,the tempering modification is recommended for large-scale forgings,in which relatively high quenching rates are difficult to achieve.

关键词： Bainite steel Retained austenite Impact toughness

Interaction between microporous magnesia castable and 38CrMoAl steel

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2023年第3期30卷 516-524页

作者： Cheng Yuan Yu Liu Guang-qiang Li yong-shun Zou Ao Huang The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education Wuhan University of Science and TechnologyWuhan 430081HubeiChina Hubei Provincial Key Laboratory for New Processes of Ironmaking and Steelmaking Wuhan University of Science and TechnologyWuhan 430081HubeiChina

The microporous magnesia refractory shows a promising application prospect as tundish lining due to excellent thermal insulation and slag *** effect of interaction between microporous magnesia castable and 38CrMoAl steel containing 0.876 wt.%Al on the cleanliness of 38CrMoAl steel was studied and compared with that of fused magnesia *** results show that the micropores in the microporous magnesia castable can promote the formation of dense and continuous MgO-Al_(2)O_(3)layer,which can inhibit the further pollution of molten steel by refractories,whereas the MgO-Al_(2)O_(3)layer formed in test of fused magnesia castable is not *** 30 min holding,the total oxygen content in the steel samples for the test of microporous magnesia castable is only 42.2%of that for the test of fused magnesia *** inclusions in the steel samples for the test of microporous magnesia castable are also less than those for the test of fused magnesia *** shows that microporous magnesia castable is a promising tundish refractory for the preparation of clean high-Al steel.

关键词： Microporous magnesia castable Fused magnesia castable High-Al steel Cleanliness Tundish lining refractory

Identifying influential spreaders in complex networks based on entropy weight method and gravity law

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2020年第4期29卷 582-590页

作者： xiao-Li Yan Ya-Peng Cui shun-Jiang Ni Institute of Public Safety Research Tsinghua UniversityBeijing 100084China Department of Engineering Physics Tsinghua UniversityBeijing 100084China Beijing Key Laboratory of City Integrated Emergency Response Science Beijing 100084China

In complex networks,identifying influential spreader is of great significance for improving the reliability of networks and ensuring the safe and effective operation of ***,it is widely used in power networks,aviation networks,computer networks,and social networks,and so *** centrality methods mainly include degree centrality,closeness centrality,betweenness centrality,eigenvector centrality,k-shell,***,single centrality method is onesided and inaccurate,and sometimes many nodes have the same centrality value,namely the same ranking result,which makes it difficult to distinguish between *** to several classical methods of identifying influential nodes,in this paper we propose a novel method that is more full-scaled and universally *** into account in this method are several aspects of node’s properties,including local topological characteristics,central location of nodes,propagation characteristics,and properties of neighbor *** view of the idea of the multi-attribute decision-making,we regard the basic centrality method as node’s attribute and use the entropy weight method to weigh different attributes,and obtain node’s combined ***,the combined centrality is applied to the gravity law to comprehensively identify influential nodes in ***,the classical susceptible-infected-recovered(SIR)model is used to simulate the epidemic spreading in six real-society *** proposed method not only considers the four topological properties of nodes,but also emphasizes the influence of neighbor nodes from the aspect of *** is proved that the new method can effectively overcome the disadvantages of single centrality method and increase the accuracy of identifying influential nodes,which is of great significance for monitoring and controlling the complex networks.

关键词： complex networks influential nodes entropy weight method gravity law

Applying physics informed neural network for flow data assimilation

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2020年第6期32卷 1050-1058页

作者： xiao-dong Bai yong Wang Wei Zhang Ministry of Education Key Laboratory of Coastal Disaster and Defence Hohai UniversityNanjing210098China Max Planck Institute for Dynamics and Self-Organization GöttingenGermany Science and Technology on Water Jet Propulsion Laboratory Marine and Research Institute of ChinaShanghai200011China

Data assimilation(DA)refers to methodologies which combine data and underlying governing equations to provide an estimation of a complex *** informed neural network(PINN)provides an innovative machine learning technique for solving and discovering the physics in *** encoding general nonlinear partial differential equations,which govern different physical systems such as fluid flows,to the deep neural network,PINN can be used as a tool for *** to its nature that neither numerical differential operation nor temporal and spatial discretization is needed,PINN is straightforward for implementation and getting more and more attention in the *** this paper,we apply the PINN to several flow problems and explore its potential in fluid *** the mesoscopic Boltzmann equation and the macroscopic Navier-Stokes are considered as physics *** first introduce a discrete Boltzmann equation informed neural network and evaluate it with a one-dimensional propagating wave and two-dimensional lid-driven cavity *** laminar cavity flow is also considered as an example in an incompressible Navier-Stokes equation informed neural *** parameterized Navier-Stokes,two turbulent flows,one within a C-shape duct and one passing a bump,are studied and accompanying pressure field is *** examples end with a flow passing through a porous *** in this paper show that PINN provides a new way for intelligent flow inference and identification,ranging from mesoscopic scale to macroscopic scale,and from laminar flow to turbulent flow.

关键词： Data assimilation(DA) deep learning physics informed neural network hydrodynamics

Skeleton-trimmed leggero pillar[5]arene:Amorphous and non-porous material for highly-selective haloalkane separation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2023年第2期34卷 1-2页

作者： xiao-yong Yu yong Chen College of Chemistry State Key Laboratory of Elemento-Organic ChemistryNankai UniversityTianjin 300071 China

Halogenated alkanes are high-value chemical feedstocks in synthetic chemistry and petrochemical industry[1,2].Therefore,the separation of halogenated alkane isomers is one of the necessary chemical processes in the petrochemical ***,the isomers normally have close boiling points due to the same molecular weight and similar chemical structure,which makes it difficult to separate the isomers with high purity by traditional methods such as ***,it is of great significance for petrochemical industry to find an efficient and energy-saving scheme to separate halogenated alkanes isomers.

关键词： isomers separation alkanes

An Almost Sure Central Limit Theorem for Self-normalized Weighted Sums

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2013年第1期29卷 79-92页

作者： yong ZHANG xiao-yun YANG College of Mathematics Jilin University

Let X, X1, X2, be a sequence of nondegenerate i.i.d, random variables with zero means, which is in the domain of attraction of the normal law. Let （ani, 1 ≤ i ≤n,n ≥1} be an array of real numbers with some suitable conditions. In this paper, we show that a central limit theorem for self-normalized weighted sums holds. We also deduce a version of ASCLT for self-normalized weighted sums.

关键词： almost sure central limit theorem self-normalized weighted sums domain of attractio of thenormal law

Numerical investigation of an advanced aircraft model during pitching motion at high incidence

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2016年第2期59卷 276-288页

作者： LIU Jian SUN HaiSheng HUANG yong JIANG yong xiao ZhiXiang School of Aerospace Engineering Tsinghua University Beijing 100084 China China Aerodynamics Research and Development Center Mianyang 621000 China

An unsteady Reynolds averaged Navier–Stokes(URANS) method combined with a rigid dynamic mesh technique was developed to simulate unsteady flows around complex configurations during pitching motion. First, a test case with the NACA0012 airfoil was selected to validate the numerical methods and our in-house codes. Then, we evaluated the unsteady flows around an advanced aircraft model during harmonic pitching motion at high incidence. The effects of pitching motion on the hysteresis of aerodynamic force, the evolution of the leading-edge vortex, and the distribution of pressure on the model's surface were analyzed in detail. The roles of several significant parameters such as the reduced frequency and pitching amplitude were revealed. Several conclusions were found: pitching motion would delay the initiation of the leading-edge vortex, strengthen the vorticity, postpone the occurrence of vortex breakdown, and weaken the massively separated flows, thus causing additional aerodynamic force. Two categories of critical reduced frequency have been found, which divide the influence of reduced frequency on aerodynamic force into three stages, called the linear increasing range, slowly increasing range, and constant range. The first-order phase lag between the aerodynamic force and the incidence is a constant that is independent of the amplitude when the reduced frequency is sufficiently high. A scaled maximum value of C_L is proposed; it depends only on the reduced frequency(instead of the amplitude), and increases linearly when the reduced frequency is sufficiently low.

关键词： pitching motion hysteresis critical reduced frequency phase lag scaled maximum of CL