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Spherical cavity-expansion model for penetration of reinforced-concrete targets

Acta Mechanica Sinica 2019年第4期35卷 535-551页

作者： Y.j.deng W.j.Song X.W.Chen Institute of Systems Engineering China Academy of Engineering PhysicsP.O.Box 919-416Mianyang 621999China Shock and Vibration of Engineering Materials and Structures Key Laboratory of Sichuan Province Mianyang 621000China Department of Civil Engineering and Architecture Southwest University of Science and TechnologyMianyang 621000China Department of Mechanics and Engineering Science College of EngineeringPeking UniversityBeijing 100871China Advanced Research Institute for Multidisciplinary Science Beijing Institute of TechnologyBeijing 100081China State Key Lab of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China

The feature of reinforcing bars is introduced into dynamic cavity-expansion theory. Based on the elastic-plastic response penetration model of plain (i.e., unreinforced) concrete (Forrestal and Tzou, 1997), a dynamic spherical cavity-expansion penetration model for reinforced-concrete targets is developed with consideration of the circumferential restriction effect derived from reinforcing bars in the crushed region. The theoretical solution and simplified calculation formula for the cavity radial stress in incompressible and compressible reinforced concrete are obtained by introducing a reinforcement ratio as the volume fraction of rebars in the concrete target. A damping function is presented to describe the restriction effect of a single layer of reinforcing bars on the surrounding concrete, thus establishing a model to calculate the penetration resistance of multilayer reinforced-concrete targets. Compared with test data for the penetration depth, this model considering the circumferential restriction effect produces better results compared with the existing theory.

关键词： Dynamic cavity-expansion theory Reinforced concrete Penetration resistance Reinforcement ratio

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Number matters:control of mammalian mitochondrial DNA copy number

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journal of Genetics and Genomics 2009年第3期36卷 125-131页

作者： Laura L.Clay Montier janice j.deng Department of Cellular and Structural Biology The Barshop Institute for Longevity and Aging Studies University of Texas Health Science Center at San Antonio

Regulation of mitochondrial biogenesis is essential for proper cellular functioning. Mitochondrial DNA （mtDNA） depletion and the resulting mitochondrial malfunction have been implicated in cancer, neurodegeneration, diabetes, aging, and many other human diseases. Although it is known that the dynamics of the mammalian mitochondrial genome are not linked with that of the nuclear genome, very little is known about the mechanism of mtDNA propagation. Nevertheless, our understanding of the mode of mtDNA replication has ad- vanced in recent years, though not without some controversies. This review summarizes our current knowledge of mtDNA copy number control in mammalian cells, while focusing on both mtDNA replication and turnover. Although mtDNA copy number is seemingly in excess, we reason that mtDNA copy number control is an important aspect of mitochondrial genetics and biogenesis and is essential for normal cellular function.

关键词： mitochondria DNA copy number DNA turnover replication

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Further numerical investigation on concrete dynamic behaviors with considering stress non-equilibrium in SHPB test based on the waveform features

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Acta Mechanica Sinica 2020年第4期36卷 873-886页

作者： T.H.Lv X.W.Chen Y.j.deng G.Chen State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China Advanced Research Institute of Multidisciplinary Science Beijing Institute of TechnologyBeijing 100081China Shock and Vibration of Engineering Materials and Structures Key Laboratory of Sichuan Province Southwest University of Science and TechnologyMianyang 621000China Institute of Systems Engineering China Academy of Engineering PhysicsMianyang 621999China

In this study,with the meso-scale model reliably validated in our previous work(Construction and Building Materials,2018),the waveform features of plain concrete under various loading conditions and especially with considering stress non-equilibrium are reliably reproduced and *** with waveform features,the violation indicator of the specimen stress equilibrium in the split Hopkinson pressure bar test is identified for concrete-like damage softening *** concrete material behaviors for stress non-equilibrium are further analyzed,*** dynamic increase factor(DIF)and damage development,*** conception of“damage failure volume”is introduced,and a new method of defining the development of concrete dynamic damage is given in the nimierical ***’s more,the“compression wave”and“double peak”phenomena observed in the experiment are further interpreted based on the means of numerical *** features how to reflect the concrete material properties is also *** results show that,the disappearance of the“double peak” phenomenon of reflection curve under high strain rate can be regarded as the indicator of the violation of stress *** the violation of the stress equilibrium,the relevant DIFs of the concrete specimen will not change ***,the concrete specimen will turn into structural response from material *** conception of“damage failure volume”can well explain the generation of the“double peak”phenomenon of the reflection *** “compression wave” phenomenon of reflection curve under lower strain rates is derived from the unloading expansion recovery of the concrete ***,under the same loading condition,the amplitude of the first peak of the reflection curve can be used as the evaluation standard of the bonding quality between mortar and aggregates.

关键词： Concrete material Split Hopkinson pressure bar test Numerical investigation Waveform feature Stress non-equilibrium Damage failure volume

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EFFECT　OF　ANNEALING　TEMPERATURE　ON　TEXTURE　OF　COLD－ROLLED　Ni₄₇Ti₄₄Nb₉　SHEET

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中国有色金属学会会刊：英文版 1995年第1期5卷 88-93页

作者： YANG, Gj XIE, LY HU, WY deng, j HAO, SM NW INST NONFERROUS MET RES BAOJI 721014PEOPLES R CHINA NORTHEASTERN UNIV SHENYANG 110006PEOPLES R CHINA

ＥＦＦＥＣＴＯＦＡＮＮＥＡＬＩＮＧＴＥＭＰＥＲＡＴＵＲＥＯＮＴＥＸＴＵＲＥＯＦＣＯＬＤ－ＲＯＬＬＥＤＮｉ４７Ｔｉ４４Ｎｂ９ＳＨＥＥＴＹａｎｇ；ＧｕａｎｊｕｎＸｉｅ；ＬｉｙｉｎｇＨｕ；ＷｅｎｙｉｎｇＤｅｎｇ；ＪｕＨａｏ... 详细信息

ＥＦＦＥＣＴＯＦＡＮＮＥＡＬＩＮＧＴＥＭＰＥＲＡＴＵＲＥＯＮＴＥＸＴＵＲＥＯＦＣＯＬＤ－ＲＯＬＬＥＤＮｉ４７Ｔｉ４４Ｎｂ９ＳＨＥＥＴＹａｎｇ；ＧｕａｎｊｕｎＸｉｅ；ＬｉｙｉｎｇＨｕ；ＷｅｎｙｉｎｇＤｅｎｇ；ＪｕＨａｏ；Ｓｈｉｍｉｎｇ(Ｎｏ?..

关键词： annealing temperature Ni47Ti44Nb9 texture ODF

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EFFECT OF Si CONTENT ON ORDERING DEGREE AND ELECTROMAGNETIC CHARACTERISTICS IN FeSiAl ALLOYS

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Acta Metallurgica Sinica(English Letters) 2008年第3期21卷 191-196页

作者： T.D. Zhou L.j. deng D.F. Liang School of Microelectronics and Solid-state Electronics University of Electronic Science and Technology of China Chengdu 610054 China School of Materials Science and Engineering Xihua University Chengdu 610039 China

FeSiAl alloys ribbons synthesized by melt-quench were annealed in vacuum at 873 K for 60 rain. The flaky powders were prepared by milling the annealed ribbons for 70 h. After milling, the powders were heat treated at 573 K for 90 rain. The ordering degree of the powders lattice structure was analyzed by X-ray diffraction （XRD）. The measurement of specific saturation magnetization was carried out by vibrating samples magnetometer （VSM）. Complex permittivity and complex permeability in the frequency band of 0.5-18 GHz were measured with the vector network analyzer. The ordering degree of the superlattice structure increased from 0.2＇7 to 0.49. Complex permittivity and complex permeability decreased with increasing Si content. After ordering, the specific saturation magnetization decreased from 134.2 to 85.0 ***-1. For use in anti-EMI material, the total contents of Si and Al in FeSiAl alloys should be controlled at a low level.

关键词： Flaky powder Ordering degree Specific saturation magnetization Complex permittivity Complex permeability

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Electron Structure and Microwave Absorbing Ability of Flaky FeSiAl Powders

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journal of Materials Science & Technology 2011年第2期27卷 170-174页

作者： T.D.Zhou D.F.Liang L.j.deng D.C.Luan Xihua University Chengdu 610039China State Key Laboratory of Electronic Thin Films & Integrated Devices University of Electronic Science and Technology of ChinaChengdu 610054China

Soft magnetic metallic materials have been widely used for absorbing electromagnetic *** Fe 86 t Si t Al 14（t=9,11,14 and 16） alloys powders were prepared from melt-quenched ribbons by annealing and *** a previous report we discussed the order-disordered structure of this *** this article,we studied their electron *** electron numbers of（111） and（100） plane increase with increasing Si content but Bohr magneton *** permittivity and complex permeability are both decreased with increasing Si content *** lowest value of reflectivity among the four alloys is originated from Fe 70 Si 14 Al *** peak values of reflectivity are all lower than 10 dB,and the absorbing frequency range（R 10 dB） increases from 1 to 2 GHz when t reaches 16.

关键词： Flaky powders Specific saturation magnetism Bohr magneton Absorbing ability

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Dynamic buckling mechanism of pillar rockbursts induced by stress waves

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journal of Rock Mechanics and Geotechnical Engineering 2019年第5期11卷 944-953页

作者： j.deng N.S.Kanwar M.D.Pandey W.-C.Xie Department of Civil Engineering Lakehead UniversityThunder BayOntarioP7B 5E1Canada Centre of Excellence for Sustainable Mining and Exploration Lakehead UniversityThunder BayOntarioP7B 5E1Canada Department of Civil and Environmental Engineering University of WaterlooWaterlooOntarioN2L 3G1Canada

Rockbursts are sudden and violent rock failures that can lead to huge production and equipment losses,injury or death of mining *** has been regarded as one of the key mechanisms of rockbursts,which are often induced by dynamic loads from mining excavations,such as drilling and blasting in underground *** paper attempts to investigate the dynamic buckling mechanism of pillar rockbursts in underground mining,by considering rockbursts as a dynamic stability problem of underground rock *** results include:(1)A new explanation of the“sudden and violent”phenomenon of rockbursts,characterized by exponential growth of the amplitudes of transverse displacement responses,even in the presence of rock damping;(2)Identification of the critical role in inducing rockbursts of dynamic loads that bear frequencies approximately double the natural pillar frequency;(3)The greater influence on rockburst occurrence of the amplitude of dynamic component relative to the static component of loads;and(4)Quantification of the relative effects of stress waveform of dynamic loads on pillar rockbursts,which are in decreasing order if other parameters remain constant:rectangular,sinusoidal,and exponential *** examples are provided and limitations of the approach are *** research is motivated by the on-going and ubiquitous occurrence of rockbursts in underground excavations all around the *** contrast to conventional methods that use rock specimens or rock materials to study rockbursts,this investigation emphasizes the structural effects on rockbursts,which has potential applications in hard rock mining engineering.

关键词： Pillar rockbursts Buckling mechanism Stress waves Structural rock mechanics

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COUPLED NUMERICAL SIMULATION OF STEEL FLOW AND SOLIDIFICATION IN SOFT-CONTACT BILLET MOLD

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Acta Metallurgica Sinica(English Letters) 2002年第5期15卷 471-478页

作者： A.Y. deng and j.C. HeKey Laboratory for Electromagnetic Processing of Materials, Ministry of Education, Northeastern University, Shenyang 110004, China Key Laboratory for Electromagnetic Processing of Materials Ministry of Education Northeastern University

A coupled model including electromagnetic field, fluid dynamic, heat transfer and solidification, is developed and applied to the numerical simulation of steel flow and solidification in a 100mm × 100mm soft-contact mold. In this study, the 3D finite difference method and non-staggered grid system for fluid flow with body fitted coordinate were employed. Numerical results show that the electromagnetic force mainly affects the steel flow at upper part of mold, especially in the vicinity of meniscus. There exist upward flows covering the surfaces of the billet due to the concentration of electromagnetic force on the upper part of the billet. This flows join together and form a downward flow near the SEN, so a distinct circulating flow zone is formed at upper part of mold. After applying electromagnetic force, the steel velocity is improved and the temperature is raised. The strong stirring of electromagnetic force on liquid steel makes the kinetic energy on free surface increase. It is clearly seen that the solidification start point shifts downward in soft contact mold. As a result, the initial shell thickness gets thin and the initial solidification shell length is shortened.

关键词： continuous casting mold electromagnetic force solidification numerical simulation

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Gait Recognition Under Different Clothing Conditions Via Deterministic Learning

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IEEE/CAA journal of Automatica Sinica 2024年第6期11卷 1530-1532页

作者： Muqing deng Cong Wang School of Automation Guangdong University of TechnologyGuangzhou 510006China School of Control Science and Engineering Shandong UniversityJinan 250100China

Dear Editor,This letter deals with the robustness problem of gait recognition method against maximum number of clothing *** selecting four kinds of time-varying silhouette features,gait dynamics underlying different individuals’gait features is effectively modeled by radial basis function(RBF)neural networks through deterministic *** kind of dynamics information has little sensitivity to the variance between gait patterns under different clothing *** order to eliminate the effect of clothing differences,the training patterns under different clothing conditions further constitute a uniform training dataset,containing all kinds of gait dynamics under different clothing conditions.A rapid recognition scheme is presented on published gait *** experiments demonstrate the efficacy of the proposed method.

关键词： networks neural individual

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EFFECT OF SPECIMEN SIZE ON j_R RESISTANCE CURVE

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Acta Metallurgica Sinica(English Letters) 1996年第5期9卷 350-354页

作者： H.P. Chen and Z.j. deng (State Key Lab. for Mechanical Behavior of Materials, Xi’an jiaotong University, Xi’an 710049, China)

The effect of specimen thinkness on jR resistance curve has been investigated using low and middle strength steels. As the j dominance regime is reached, the initial j-integral values, j(i), are definite even if the elastic component ji(e) and plastic component ji(p)vary with the thinkness of specimen. The wider the specimen width, the larger the ji(e)/ji and the smaller the ji(p)/ji. The crack propagation resistance, djR/da and djp/da, decreases, while dje/da increases linearly with increasing specimen *** on the above experimental results, an empirical formula dj/da = α+β. B is given, which can be used to evaluate the safety of practical structural components.A modified j-integral is presented, upon which a new view is Put forward that the increase in crack growth resistance is induced mainly by the increase in the plastic j-integral component with the crack propagation,

关键词： fracture mechanics j-R curve modified j elastic-plastic fracture

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