Experimental Research on Fatigue Damage of Reinforced Concrete Rectangular Beam

Fangping Liu,Jianting Zhou 대한토목학회 2018 KSCE Journal of Civil Engineering Vol.22 No.9

In order to acquire the law of the fatigue damage development of reinforced concrete rectangular beams, the ultimate load carrying capacity of a tested beam was measured through the static loading test. The carrying capacity of the beam was then taken as the basis of loading amplitudes for the fatigue tests and the constant amplitude fatigue loading tests under different load levels were carried out for another three beams. The experimental results show that the crack in the beam is composed of the oblique crack in the bending shear section and the vertical crack in the pure bending section. The fatigue cracks are symmetrically distributed along the length direction, and the two sides are basically the same. The fatigue fracture of the test beam occurs in one main cracks located in the middle section of the span. According to the crack width, height and the number of cracks, the whole fatigue test process can be roughly divided into three stages, that is, the rapid development stage, the stable stage and the failure stage. The development of the deflection of the beam and the strain increment of the steel bar and the concrete increased significantly at the beginning of the fatigue cycle; with the increase of cycle number of fatigue load, the growth rate slowed down and entered a relatively stable stage of development; as fatigue destruction gets nearer, the speed became great again. The stiffness of the beam has a relatively large decrease at the beginning of the fatigue loading. In the middle of a longer period of time, it is basically in a linear decline phase. Before the failure, the stiffness decreases greatly. Overall, the stiffness degradation of the beam shows a more obvious monotonic decreasing “S” curve. In a word, many aspects reflect that the fatigue damage of reinforced concrete rectangular beam has obvious three stages damage law. In the early and later stages of fatigue test, the damage is developing rapidly; and in the intermediate stage of fatigue test, the damage development is relatively stable.

Effect of Y2O3 content on Ni60 alloy cladding layer

Fangping Yao,Zhi Ming,Jinhua LI,Xiang Chen 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.9

Six kinds of Ni60 alloy coatings with different percentage of Y 2 O 3 were prepared by laser cladding. A metallurgical microscope was used to analyze the morphology of the cladding layer. Scanning electron microscopy and EDS energy spectrum analysis were used to characterize the microstructure and element segregation of the cladding layer. A Vickers microhardness tester was used to measure the hardness of the cladding layer. Finally, a friction and wear tester established the friction and wear properties of the cladding layer. The study results show that Y 2 O 3 can significantly reduce the height of the cladding layer and increase the width of the cladding layer; it can also improve the structure refinement and element segregation of the cladding layer. The microhardness of the cladding layer is significantly improved compared to the Ni60 alloy coating without Y 2 O 3 , thereby enhancing the wear resistance of the coating.

Game among Mobile Operators, Bank and the Third-party Payment Services Provider in Mobile Payment Market

Miao Miao,Fangping Xiong,Jing Zhou 보안공학연구지원센터(IJUNESST) 2014 International Journal of u- and e- Service, Scienc Vol.7 No.1

WAVE HEIGHT DISTRIBUTION FOR SPILLING WAVES IN THE SURF ZONE

TAO YOU,ZIDAN ZHAO,FANGPING ZHONG,ZUZHI WANG 한국수자원학회 2005 한국수자원학회 학술대회 Vol.2005 No.1

Research on Influencing Factors of Chinese Mobile Communication Customers’ Switching Intention by Mobile Number Portability

Miao Miao,Jia Jia,Rui Tingting,Xiong Fangping,Li haibo 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.4

In order to explore the Influencing Factors of Switching Intention by Mobile Number Portability .We build up a structural equation model for Chinese mobile customers’ influence factors on MNP intention. Including competitive attraction, subjective norm, and policy perception, customer satisfaction, switching barriers, network quality, awareness rates, perceived service quality, usage habits and switching cost. According to empirical analysis, we find that customers with different perceive levels in MNP polices have significant differences in switching intention. And through the analysis and comparison, we find that the influence factors and the path coefficients of the customers’ switching intention are also different when they have different perceive levels in MNP policy.

Simulation of in-situ preheating of ni-based multi-layer and multi-pass coatings on H13 steel

Honggang Yin,Jinhua LI,Liwei Zhao,Fangping Yao 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.9

COMSOL was used to simulate the temperature field of the preheating and nonpreheating processes of the laser cladding multi-layer and multi-pass coating, and experimental verification was carried out. The results show that the temperature gradient value of the coating at the Z-axis is much larger than the value at the X and Y-axis, respectively. It indicates that the coating is sensitive to cracks at the Z-axis. After preheating, the quality of the coating is improved, and the results of the geometric morphology in experiments are basically consistent with the results of simulation. With increase in coating temperature, the cladding efficiency increased. The difference of temperature between the first and second layer was significantly reduced. The temperature gradient value at the Z-axis decreased. The coating grain structure presents as refined and well-distributed. The temperature gradient size in each layer decreased with the number of coatings increasing.

Dynamic behavior of lifting pipe with equivalent model under mining vessel heave motion

QingHui Song,HaiYan Jiang,QingJun Song,Linjing Xiao,FangPing Yan 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.5

The lifting pipe is a key component of deep sea mining whose dynamic response directly affects the safety of the lift-ing operation. The objective of this paper was to investigate the effects of heave motion and sailing velocity of mining vessel and the buffer mass on the dynamic response of lifting pipe. First, an equivalent model of the lifting pipe was established, and the natural frequency and dynamic response of the lifting pipe equivalent model were determined with consideration of the wave action by the method of separated variables. Secondly, the reliability of the equivalent model was verified by simulating a 5000 m stepped pipe with OrcaFlex software. Then the dynamic displacement, axial tension, axial stress of the lifting pipe under different sea conditions and sailing velocities were studied, and the main factors affecting the dynamic response of the pipe described. By comparing the simulation results of actual and equivalent models, the equivalent model can be used to analyze the longitudinal vibration characteristics of the lifting pipe. The sailing velocity of the mining vessel has little effect on the dynamic response of the lifting pipe, but the surface wave has a significant effect.

Intelligent cooling control for mass concrete relating to spiral case structure

Ning, Zeyu,Lin, Peng,Ouyang, Jianshu,Yang, Zongli,He, Mingwu,Ma, Fangping Techno-Press 2022 Advances in concrete construction Vol.14 No.1

The spiral case concrete (SCC) used in the underground powerhouse of large hydropower stations is complex, difficult to pour, and has high requirements for temperature control and crack prevention. In this study, based on the closed-loop control theory of "multi-source sensing, real analysis, and intelligent control", a new intelligent cooling control system (ICCS) suitable for the SCC is developed and is further applied to the Wudongde large-scale underground powerhouse. By employing the site monitoring data, numerical simulation, and field investigation, the temperature control quality of the SCC is evaluated. The results show that the target temperature control curve can be accurately tracked, and the temperature control indicators such as the maximum temperature can meet the design requirements by adopting the ICCS. Moreover, the numerical results and site investigation indicate that a safety factor of the spiral case structure was sure, and no cracking was found in the concrete blocks, by which the effectiveness of the system for improving the quality of temperature control of the SCC is verified. Finally, an intelligent cooling control procedure suitable for the SCC is proposed, which can provide a reference for improving the design and construction level for similar projects.

Implantable Thin-film Porous Microelectrode Array (P-MEA) for Electrical Stimulation of Engineered Cardiac Tissues

Hiren V. Trada,Venkat Vendra,Joseph P. Tinney,Fangping Yuan,Douglas J. Jackson,Kevin M. Walsh,Bradley B. Keller 한국바이오칩학회 2015 BioChip Journal Vol.9 No.2

We have designed, fabricated, and validated a novel porous, multielectrode array (P-MEA) device capable of low-voltage electrical stimulation of engineered cardiac tissues (ECTs). The primary advantage of this device is the ability to successfully function at a very low voltage thus minimizing any undesirable oxidative by-products in the culture environment or cell injury. Major features of our P-MEA include dimensions of 10 mm width and 82 mm length, four arms to allow movement of the individual pads within ECTs, each embedded electrode arm incorporates eight 100 μm×200 μm rectangular pores surrounding a 950 μm×340 μm exposed electrode, large pads on either side of the porous embedded device to function as current return electrodes, suture holes to aid in vivo suturing and stabilization, and an eight electrode connector pads. Average thickness of the Ni/Au electrodes was 20 nm of nickel and 400 nm of old, an average electrode film thickness of 0.4 μm, and a double polyimide layer thickness of 16 μm. Electrode resistance ranged from 69.45 Ω to 78.52 Ω. Electrochemical impedance spectroscopy confirmed that the P-MEA operates in the 0.01 V to 1.0 V range with favorable charge transfer characteristics. Proof of principle experiments confirmed the ability of the P-MEA to effectively embed within ECT and electricallystimulate ECT during chronic, in vitro culture. Histology imaging shows that the embedding of the device has no adverse effects on the ECT and the cardiomyocytes are aligned within the tissue. Experiments are ongoing to evaluate the role of electrical stimulation on the maturation and function of ECTs. We have designed, fabricated, and validated a novel porous, multielectrode array (P-MEA) device capable of low-voltage electrical stimulation of engineered cardiac tissues (ECTs). The primary advantage of this device is the ability to successfully function at a very low voltage thus minimizing any undesirable oxidative by-products in the culture environment or cell injury. Major features of our P-MEA include dimensions of 10 mm width and 82 mm length, four arms to allow movement of the individual pads within ECTs, each embedded electrode arm incorporates eight 100 μm×200 μm rectangular pores surrounding a 950 μm×340 μm exposed electrode, large pads on either side of the porous embedded device to function as current return electrodes, suture holes to aid in vivo suturing and stabilization, and an eight electrode connector pads. Average thickness of the Ni/Au electrodes was 20 nm of nickel and 400 nm of gold, an average electrode film thickness of 0.4 μm, and a double polyimide layer thickness of 16 μm. Electrode resistance ranged from 69.45 Ω to 78.52 Ω. Electrochemical impedance spectroscopy confirmed that the P-MEA operates in the 0.01 V to 1.0 V range with favorable charge transfer characteristics. Proof of principle experiments confirmed the ability of the P-MEA to effectively embed within ECT and electrically stimulate ECT during chronic, in vitro culture. Histology imaging shows that the embedding of the device has no adverse effects on the ECT and the cardiomyocytes are aligned within the tissue. Experiments are ongoing to evaluate the role of electrical stimulation on the maturation and function of ECTs.

The Endo-β-1,4-Glucanase of Bacillus amyloliquefaciens Is Required for Optimum Endophytic Colonization of Plants

( Xiaojing Fan ),( Ruixian Yang ),( Sixin Qiu ),( Xueqing Cai ),( Huasong Zou ),( Fangping Hu ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.5

The eglS gene in Bacillus amyloliquefaciens encodes an endo-β-1,4-glucanase that belongs to glycosyl hydrolase family 5. In this study, a disruption mutant of gene eglS was constructed to examine its role in bacterial adaptation in plants. The mutant TB2k, eglS gene inactivated bacterial strain, was remarkably impaired in extracellular cellulase activity. When inoculated on Brassica campestris, the TB2k population was reduced by more than 60% compared with the wild-type strain in the root, stem, and leaf tissues. Overexpression of eglS in the wild-type strain increased the bacteria population in the plant tissues. Further studies revealed that the transcription level of eglS was correlated with bacterial population. These data demonstrate that endo-β-1,4-glucanase of B. amyloliquefaciens is required for its optimal endophytic colonization.