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Moment Redistribution Effect of the Continuous Glass Fiber Reinforced Polymer-Concrete Composite Slabs Based on Static Loading Experiment

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Structural Durability & Health Monitoring 2025年第1期19卷 105-123页

作者： zhao-Jun Zhang wen-Wei wang Jing-Shui Zhen bo-cheng Li De-cheng Cai Yang-Yang Du hui Huang Offshore Oil Engineering Co.Ltd. Tianjin300461China Department of Bridge Engineering School of TransportationSoutheast UniversityNanjing211189China

This study aimed to investigate the moment redistribution in continuous glass fiber reinforced polymer(GFRP)-concrete composite slabs caused by concrete cracking and steel bar yielding in the negative bending moment *** experimental bending moment redistribution test was conducted on continuous GFRP-concrete composite slabs,and a calculation method based on the conjugate beam method was *** composite slabs were formed by combining GFRP profiles with a concrete layer and supported on steel beams to create two-span continuous composite slab *** methods,epoxy resin bonding,and stud connection,were used to connect the composite slabs with the steel *** experimental findings showed that the specimen connected with epoxy resin exhibited two moments redistribution phenomena during the loading process:concrete cracking and steel bar yielding at the internal *** contrast,the composite slab connected with steel beams by studs exhibited only one-moment redistribution phenomenon throughout the loading *** the concrete at the internal support cracked,the bending moment decreased in the internal support section and increased in the midspan *** the steel bars yielded,the bending moment further decreased in the internal support section and increased in the mid-span *** GFRP profiles do not experience cracking,there was no significant decrease in the bending moment of the mid-span *** test specimens experienced compressive failure of concrete at the mid-span *** results showed good agreement between the calculated and experimental values of bending moments in the mid-span section and internal support *** proposed model can effectively predict the moment redistribution behavior of continuous GFRP-concrete composite slabs.

关键词： Moment redistribution GFRP-concrete composite slabs bending moment experimental study analysis model

Precipitation behavior of 14H-LPSO structure in Mg–12Gd–2Er–1Zn–0.6Zr Alloy

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Rare Metals 2016年第5期35卷 367-373页

作者： Kai wen wen-bo Du Ke Liu zhao-hui wang Shu-bo Li College of Materials Science and Engineering Beijing University of Technology

The microstructures of as-cast and as-solution Mg–12Gd–2Er–1Zn–0.6Zr alloys were investigated by optical microscopy（OM）, scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, highresolution transmission electron microscopy（HRTEM）X-ray diffraction（XRD） and selected-area electron diffraction（SAED） in the present investigation. The results show that the primary eutectic phase Mg5（Gd, Er, Zn） and some flocculent features are found in the as-cast alloy; the SAED pattern indicates that these flocculent features are the dense areas of stacking faults. The 14H-LPSO structure precipitates in the temperature range of 673–793 K, and the volume fraction of 14H-LPSO structure increases with the extension of heating time; however, there is no precipitation of 14H-LPSO structure when the temperature reaches up to 803 K. In addition, the Mg5（Gd, Er, Zn） phase dissolves gradually along with the precipitation of 14H-LPSO structure.

关键词： Mg–Gd–Er–Zn–Zr alloy Dense stacking faults area Heat treatment Microstructure

Microstructures and mechanical properties of homogenization and isothermal aging Mg–Gd–Er–Zn–Zr alloy

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Rare Metals 2016年第6期35卷 443-449页

作者： Kai wen wen-bo Du Ke Liu zhao-hui wang Shu-bo Li College of Materials Science and Engineering Beijing University of Technology

The effects of homogenization and isothermal aging treatment on the mechanical properties of Mg-12Gd- 2Er-1Zn-0.6Zr （wt%） alloy were investigated. The precipitated long-period stacking order （LPSO） structure and the aging precipitation sequence of the conditioned alloys were observed and analyzed, respectively. The results indicate that the 14H-LPSO structure occurs after the homogenization treatment and the 131 phase forms after the isothermal aging process. These two independent processes could be controlled by the precipitation temperature range. The significant increase in the elongation of the as-cast alloy after homogenization treatment is attributed to the disappearance of the coarse primary Mgs（Gd, Er, Zn） phase and the presence of the 14H-LPSO structure. The precipitation sequence of the investigated alloy is α-Mg（SSS）/β″（D019）/β′（cbco）/β. Furthermore, the yield tensile strength （YTS） and ultimate tensile strength （UTS） values of the isothermal aging alloy have a great improvement, which could be attributed to the high density of the precipitated β′ phase.

关键词： Magnesium alloys Isothermal aging Mechanical properties Mg-Gd-Er-Zn(Zr) Microstructures

Joint power allocation and relay selection for decode-and-forward cooperative relay in secure communication

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The Journal of China Universities of Posts and Telecommunications 2013年第2期20卷 79-85页

作者： YANG Yun-chuan zhao hui SUN Cong wang wen-bo Key Laboratory of Universal Wireless Communications Beijing University of Posts and Telecommunications ICMSEC AMSS Chinese Academy of Sciences

In this paper, we investigate the cooperative strategy with total power constraint in decode-and-forward （DF） relaying scenario, in the presence of an eavesdropper. Due to the difference of channel for each source-relay link, not all relay nodes have constructive impacts on the achievable secrecy rate. Besides, the final achieved secrecy rate depends on both source-relay and relay-destination links in DF relaying scenario. Therefore, the principal question here is how to select cooperative strategy among relays with proper power allocation to maximize the secrecy rate. Three strategies are considered in this paper. First, we investigate the cooperative jamming （CJ） strategy, where one relay with achieved target transmission rate is selected as a conventional relay forwarding signal, and remaining relays generate artificial noise via CJ strategy to disrupt the eavesdropper. Two CJ schemes with closed-form solutions, optimal cooperative jamming （OCJ） and null space cooperative jamming （NSCJ）, are proposed. With these solutions, the corresponding power allocation is formulated as a geometric programming （GP） problem and solved efficiently by convex programming technique. Then, to exploit the cooperative diversity, we investigate the cooperative relaying （CR） strategy. An iterative algorithm using semi-definite programming （SDP） and GP together with bisection search method is proposed to optimize the cooperative relaying weight and power allocated to the source and relays. Furthermore, to exploit the advantages of both CR and CJ, we propose an adaptive strategy to enhance the security. Simulation results demonstrate that the efficiency of the proposed cooperative strategies in terms of secrecy rate.

关键词： physical layer security CJ CR power allocation SDP GP

Microstructural control and hardening response of Mg–6Zn–0.5Er–0.5Ca alloy

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Rare Metals 2016年第7期35卷 526-531页

作者： Xiao-Bing Zheng Ke Liu zhao-hui wang Shu-bo Li wen-bo Du School of Material Science and Engineering Beijing University of Technology

The effects of heat treatment on microstructures and hardening response of Mg-6Zn4）.5Er4）.5Ca （wt%） alloy were investigated by optical microscope （OM）, scanning elec- tron microscope （SEM）, and transmission electron microscope （TEM） in this paper. The results show that the Mg（Zn4）.5Er- 0.5Ca alloy contains Mg3Zn6Erx quasicrystalline phase （I- phase） and Ca2Mg6Zn3 phase under as-cast condition. Most of the Ca2Mg6Zn3 phases and I-phases dissolve into matrix during heat treatment at 475 ℃ for 5 h. After the as-solution alloy was aged at 175 ℃ for 36 h, a large amount of MgZn2 precipitate with several nanometers precipitate. It is suggested that the trace addition of Ca results in refining the size of the precipitate, and the presence of the nanoscale MgZn2 phase is the main factor to improve the peak-aged hardness greatly to 87 HV, which in- creases about 40 % compared with that of as-cast alloy.

关键词： Mg-6Zn-0.5Er-0.5Ca alloy Heat treatment Aging hardening

Microstructure and mechanical properties of AZ31 magnesium alloy reinforced by I-phase

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Rare Metals 2019年第8期38卷 733-738页

作者： Hai-Rong Wu wen-bo Du Shu-bo Li Ke Liu zhao-hui wang School of Materials Science and Engineering Beijing University of Technology

The particles of Mg-Zn-Gd icosahedral quasicrystal master alloy were added into the AZ31 alloy by the repeated plastic working(RPW)process in order to improve the mechanical properties of the AZ31 alloy at room *** microstructure and tensile properties of composites were investigated by scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray diffraction(XRD),and tensile testing machine at room *** results suggest that the RPW process can effectively refine the matrix and make the I-phase particles distribute *** ultimate tensile strength and the yield strength of the composites reach their maximum values of 362.3 and 330.5 MPa,respectively,when the amount of I-phase particles added is10 %.Meanwhile,the elongation of the composites decreases sharply.

关键词： I-phase Reinforced composite Repeated plastic working Mechanical property

Bit error probability of distributed Turbo coded relay systems over quasi-static Rayleigh fading channels

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The Journal of China Universities of Posts and Telecommunications 2010年第2期17卷 41-45页

作者： PENG Yue-xing WU Mu-zi zhao hui wang wen-bo Wireless Signal Processing and Network Laboratory Key Lab of Universal Wireless Communications Ministry of Education School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing 100876 China

As is known, distributed Turbo coding （DTC） performs close to the theoretic outage probability bound of a relay channel when correct decoding is assumed at the relay. However, decoding error is inevitable in practical fading channels due to the error-prone feature of radio channels, and the decoding error propagation in DTC scheme will severely degrade the error performance of the relay system. As a result, it is necessary to evaluate the error performance of the DTC scheme in multi-hop relaying wireless systems in practical fading channels. Moreover, the theoretical method of analysis provides an effective tool for obtaining the error performance besides lengthy simulations. In this article, the concept of equivalent signal-to-noise ratio （SNR） of the two-hop relay channel and the method of computing equivalent SNR are developed, and then the upper bound on the bit error probability （BEP） of DTC relay systems is analyzed by use of Turbo code＇s distance spectrum, the concept of uniform interleaver, the limit-before-averaging technique, and the union bound method. both theoretical analysis and numerical simulation are implemented for relay systems with DTC scheme over quasi-static Rayleigh fading channels. The results show that the upper bound approaches the simulation results in the medium to high SNR region.

关键词： bit error probability distributed Turbo code relay network union bound distance spectrum SNR

Microstructure and electrochemical properties of La0.8-xMMxMg0.2Ni3.1Co0.3Al0.1(x=0,0.1,0.2,0.3)alloys

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Rare Metals 2017年第8期36卷 645-650页

作者： Na Zhou wen-bo Du Pei-Long Zhang Yong-Guo Zhu zhao-hui wang Ke Liu Shu-bo Li College of Materials Science and Engineering Beijing University of TechnologyBeijing 100124China Whole Win Materials Science and Technology Co. LtdBeijing 100083China

The present study aims to improve electrochemical properties of the La-Mg-Ni-based hydrogen storage alloys through partial substitution for La by mischmetal（MM）.The La_（0.8-x）MM_xMg_（0.2）Ni_（3.1）Co_（0.3）Al_（0.1）（x=0,0.1,0.2,0.3）alloys were prepared by inductive melting,and their phase structures and electrochemical properties were studied by X-ray diffraction（XRD）,scanning electron microscope（SEM）,energy-dispersive X-ray spectrometry（EDX）and electrochemical *** show that the alloys mainly consist of La_2Ni_7-type phase,La_5Ni_（19）-type phase,LaNi_5-type phase and LaNi_3-type *** addition of MM does not change the phase compositions,while it leads to more uniform phase distribution and obviously promotes the formation of La_2Ni_7-type phase which possesses favorable electrochemical *** studies indicate that the substitution for La by MM could effectively improve the high rate dischargeability（HRD）of the alloy electrode,and the optimal value of HRD_（1500）（HRD at 1500 mA·g^（-1））increases from 40.63%（x=0）to 60.55%（x=0.3）.Although the activation properties of the alloy electrodes keep almost unchanged,both the maximum discharge capacity（C_（max））and the cycling stability are significantly improved by MM addition.

关键词： Hydrogen storage alloy Microstructure Discharge capacity High rate dischargeability Cyclingstability

Microstructure,mechanical properties and stretch formability of as-rolled Mg alloys with Zn and Er additions

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Rare Metals 2021年第8期40卷 2179-2187页

作者： Ke Liu Jing-Tao Liang wen-bo Du Shu-bo Li zhao-hui wang Zi-Jian Yu Jin-Xue Liu College of Materials Science and Engineering Beijing University of TechnologyBeijing100124China Zhengzhou Light Metal Research Institute Zhengzhou450041China

The magnesium alloy has a unique advantage in 3C fields due to its high specific strength and excellent electromagnetic shielding ***,it is difficult to deform homogeneously because of hexagonal close-packed *** the present work,the microstructure,mechanical properties and stretch formability of magnesium alloy sheets with different alloying elements were *** was indicated that a trace addition of Zn or/and Er made a key role in modifying texture,activating shear bands formation and precipitating nanoscale second phases,respectively,which resulted in an obvious improvement in both stretch formability and mechanical *** results suggested that the Mg-0.5 Zn-0.5 Er alloy sheet exhibited higher tensile strength along the rolling direction,i.e.,yield strength of 180 MPa and ultimate tensile strength of 201 MPa,accompanying with superior Erichsen value of 7.0 mm at room *** good performances of the sheet were ascribed to weakening basal texture intensity,formation of shear bands and precipitation of nanoscale W-phase(Mg_(3)Zn_(3)Er_(2)).

关键词： Mg-Zn-Er alloy Hot rolling Texture Shear band Stretch formability