Experimental and Numerical Investigation on the Behaviour of Prestressed High Strength Concrete Pile-to-pile Cap ConnectionsExperimental and Numerical Investigation on the Behaviour of Prestressed High Strength Concrete Pile-to-pile Cap Connections

Zhijian Yang,Wenjin Wang 대한토목학회 2016 KSCE JOURNAL OF CIVIL ENGINEERING Vol.20 No.5

Six Prestressed High Strength Concrete (PHC) pile-to-pile cap connections were tested to evaluate their damage process and failure modes under low cyclic loading. The hysteretic behaviour, rotation angle, ductility and bearing capacity were observed and analyzed. In addition, the effect of connecting forms and cutting-off piles on seismic performance of pile-cap connections was considered and investigated. The experimental results showed that flexural bending failure occurred in all connections. There were two main failure modes. One was tensile rupturing of prestressed bars and headings, resulting in loss of bearing capacity of the connections. The other type was more severe damage due to anchor bar yield and appearance of plastic hinge. Moreover, bond-slip failure of anchor bars was not observed in the cap, and the length of anchor bars met requirements. The analysis indicated that the bearing capacity and energy dissipation capacity increased along with the rotation capacity of the pile connections. Nonlinear finite element models were established to analyze the mechanical properties of these connections using OpenSees. The load-displacement curves obtained from the numerical analysis agreed with the experimental results. The effects of various parameters on the behaviour of the connections were conducted based on the numerical model.

Study on the Flexural Performance of Prestressed High Strength Concrete Pile

Zhijian Yang,Guochang Li,Wenjin Wang,Yajun Lv 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.10

Four prestressed high strength concrete (PHC) piles under low-cycle loading and two piles under monotonic flexural loading were tested to study the test phenomena, failure modes, hysteretic performance, ductility and bearing capacity. It was indicated that PHC piles failed suddenly and the bearing capacity decreased because of the tensile rupturing of prestressing tendons from the results, and the hysteretic curves pinched. Nonlinear finite element models were established to analyze the mechanical properties of PHC piles using ABAQUS and OpenSees. The results obtained from the numerical analysis compared well with the experimental results. In addition, nonlinear finite element models were used to study influence of the position, pattern, number and diameter of deformed bars to the PHC piles reinforced with deformed bars (PRC piles). The analysis results showed that the deformed bars should be arranged evenly in circle direction, and the bearing capacity of PRC increased with the number and diameter of deformed bars.

Flexural Behavior of High Strength Concrete Filled Square Steel Tube with Inner CFRP Circular Tube

Zhijian Yang,Guochang Li,Yan Lang,Chen Fang 대한토목학회 2017 KSCE Journal of Civil Engineering Vol.21 No.7

This paper investigates the flexural behavior of high strength concrete filled square steel beam with inner CFRP (carbon fiberreinforced polymer) circular tube by the ABAQUS/Standard solver. In addition, eight specimens were fabricated and tested to investigate the pure flexural behavior. The test data was used to verify the Finite Element Analysis (FEA) modeling and good agreement was achieved in general. Furthermore, the influences of steel yielding strength, concrete strength, steel ratio and the thickness of CFRP on the flexural performance of the specimens were analyzed by FEA. According to the analysis of bending moment versus strain curves, the materials of CFRP, steel and concrete worked well together subjected to pure bending before the CFRP tube ruptured. The results presented in this paper show that these composite beams have a very ductile response because the concrete is confined by the CFRP tube and the steel tube. The beams’ flexural response, including the flexural stiffness and the ultimate load, can be substantially improved by the inner CFRP tube. The parametric studies provide information for the development of formulae to calculate the moment capacity. A comparison of experimental failure loads with the predicted failure loads in accordance with the formulae showed good agreement.

Establishment and evaluation of a murine anb3-integrinexpressing cell line with increased susceptibility to Foot-and-mouth disease virus

Wei Zhang,Kaiqi Lian,Fan Yang,Yang Yang,Zhijian Zhu,Zixiang Zhu,Weijun Cao,Ruoqing Mao,Ye Jin,Jijun He,Jianhong Guo,Xiangtao Liu,Haixue Zheng 대한수의학회 2015 Journal of Veterinary Science Vol.16 No.3

Integrin anb3 plays a major role in various signaling pathways, cell apoptosis, and tumor angiogenesis. To examine the functions and rolesof anb3 integrin, a stable CHO-677 cell line expressing the murine anb3 heterodimer (designated as “CHO-677-manb3” cells) wasestablished using a highly efficient lentiviral-mediated gene transfer technique. Integrin subunits an and b3 were detected at the gene andprotein levels by polymerase chain reaction (PCR) and indirect immunofluorescent assay (IFA), respectively, in the CHO-677-manb3 cellline at the 20th passage, implying that these genes were successfully introduced into the CHO-677 cells and expressed stably. A plaque-formingassay, 50% tissue culture infective dose (TCID50), real-time quantitative reverse transcription-PCR, and IFA were used to detect the replicationlevels of Foot-and-mouth disease virus (FMDV) in the CHO-677-manb3 cell line. After infection with FMDV/O/ZK/93, the cell line showeda significant increase in viral RNA and protein compared with CHO-677 cells. These findings suggest that we successfully established a stableanb3-receptor-expressing cell line with increased susceptibility to FMDV. This cell line will be very useful for further investigation of anb3integrin, and as a cell model for FMDV research.

Thermal Stress Model of Transversal Forced Air-Cooled Capacitor Banks for MWPower Converters

Zhijian Yin,Rui Wu,Morten Hygum,Yongheng Yang,Huai Wang 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

Capacitor banks are key components in high power applications, the reliability of which affects the overall system lifetime. It is known that the thermal stress in each capacitor can affect the lifetime performance of the entire capacitor bank. In this paper, an analytical thermal model is presented to estimate the average capacitor thermal stress in a transversal forced air-cooled three-phase AC-filter capacitor bank for MW-level power converters. The proposed model calculates the thermal resistance of a capacitor bank considering power losses, geometry, cooling conditions and physical arrangement. With a conventional Foster thermal network, the hot-spot temperature and case temperature for each capacitor can be obtained. The experimental results on a full-scale three-phase filter capacitor bank consisting of 27 film sub-capacitors have demonstrated the effectiveness of this model.

Supercapacitors based on a nitrogen doped hierarchical porous carbon fabricated by self‑activation of biomass: excellent rate capability and cycle stability

Zhijian Zhang,Jingjing He,Xingchang Tang,Yuling Wang,Binbin Yang,Kunjie Wang,Deyi Zhang 한국탄소학회 2019 Carbon Letters Vol.29 No.6

Energy and environmental are always two major challenges for the sustainable development of the modern human being. For avoiding the serious environmental pollution caused in the fabrication process of porous carbon, a popular energy storage material, we reported a facile, green and activating agent free route hereby directly carbonizing a special biomass, Glebionis coronaria. A nitrogen doped hierarchical porous carbon with a specific surface area of up to 1007 m2 g−1 and a N doping content of up to 2.65 at.% was facilely fabricated by employing the above route. Benefiting from the peculiarly hierarchical porous morphology, enhanced wettability and improved conductivity, the obtained material exhibits superior capacitance performance, which capacitance reaches up to 205 F g−1 under two-electrode configuration, and no capacitance loss is observed after 5000 cycles. Meanwhile, the capacitance retention of the obtained material arrives up to 95.0% even under a high current density of 20 A g−1, illuminating its excellent rate capability. The fabricated nitrogen-doped hierarchical porous carbon with larger capacitance than commercial activated carbon, excellent rate capability and cycle stability is an ideal cost-efficient substitution of commercial activated carbon for supercapacitor application.

Physical systems based on Intrinsic Transistors Characteristics and Having collective Computational Abilities

Yang Wang,Zhijian Li,Bingxue Shi 대한전자공학회 1994 ICONIP : International Conference On Neural Inform Vol.3 No.1

Supercapacitors based on a nitrogen doped hierarchical porous carbon fabricated by self-activation of biomass: excellent rate capability and cycle stability

Zhang Zhijian,He Jingjing,Tang Xingchang,Wang Yuling,Yang Binbin,Wang Kunjie,Zhang Deyi 한국탄소학회 2019 Carbon Letters Vol.29 No.6

Energy and environmental are always two major challenges for the sustainable development of the modern human being. For avoiding the serious environmental pollution caused in the fabrication process of porous carbon, a popular energy storage material, we reported a facile, green and activating agent free route hereby directly carbonizing a special biomass, Glebionis coronaria. A nitrogen doped hierarchical porous carbon with a specific surface area of up to 1007 m2 g−1 and a N doping content of up to 2.65 at.% was facilely fabricated by employing the above route. Benefiting from the peculiarly hierarchical porous morphology, enhanced wettability and improved conductivity, the obtained material exhibits superior capacitance performance, which capacitance reaches up to 205 F g−1 under two-electrode configuration, and no capacitance loss is observed after 5000 cycles. Meanwhile, the capacitance retention of the obtained material arrives up to 95.0% even under a high current density of 20 A g−1, illuminating its excellent rate capability. The fabricated nitrogen-doped hierarchical porous carbon with larger capacitance than commercial activated carbon, excellent rate capability and cycle stability is an ideal cost-efficient substitution of commercial activated carbon for supercapacitor application.

On Some Skew Constants in Banach Spaces

Yuankang Fu,Zhijian Yang,Qi Liu,Yongjin Li 경북대학교 자연과학대학 수학과 2023 Kyungpook mathematical journal Vol.63 No.2

We introduce the constants E[t, X], CNJ[X] and J[t, X] to describe the asym metry of the norm. They can be seen as the skew version of the Gao’s parameter, von Neumann-Jordan constant and Milman’s moduli, respectively. We establish basic proper ties of these constants, relating them other well known constants, and use these properties to calculate the constants for specific spaces. We then use these constants to study Hilbert spaces, uniformly non-square spaces and their normal structures. With the Banach-Mazur distance, we use them to study isomorphic Banach spaces

A New Geometric Constant in Banach Spaces Related to the Isosceles Orthogonality

Yongjin Li,Zhijian Yang 경북대학교 자연과학대학 수학과 2022 Kyungpook mathematical journal Vol.62 No.2

In this paper, starting with the geometric constants that can characterize Hilbert spaces, combined with the isosceles orthogonality of Banach spaces, the orthogo nal geometric constant ΩX(α) is defined, and some theorems on the geometric properties of Banach spaces are derived. Firstly, this paper reviews the research progress of orthogo nal geometric constants in recent years. Then, this paper explores the basic properties of the new geometric constants and their relationship with conventional geometric constants, and deduces the identity of ΩX (α) and γX(α). Finally, according to the identities, the relationship between these the new orthogonal geometric constant and the geometric prop erties of Banach Spaces (such as uniformly non-squareness, smoothness, convexity, normal structure, etc.) is studied, and some necessary and sufficient conditions are obtained.