An Efficient Model to Calculate Axial Natural Vibration Frequency of Power Transformer Winding

Kaiqi Li,Jian Guo,Jun Liu,Anhong Zhang,Shaojia Yu 한국자기학회 2016 Journal of Magnetics Vol.21 No.3

In the design of transformer winding, natural vibration frequency is an important parameter. This paper presents a 2D model to calculate axial vibration natural frequency of power transformer winding based on the elastic dynamics theory, and according to the elastic support equivalent principle of radial pressboards. The 3D model to calculate natural vibration frequency can be simplified as a 2D one as the support of pressboards on the winding is same. It is verified that results of the 2D model are consistent with those of 3D one, but the former can achieve much higher calculation efficiency. It shows that increasing the width and number of pressboards can improve axial natural frequency through formula analysis and simulation, and also the relations between the changes of axial pre-compression and axial natural vibration frequency on the windings are investigated. Finally, the proposed 2D model’s effectiveness is proved when compared with tested ones.

Identification of Primary Failure Modes of Tunnel System and Influence of Supporting Structures on Tunnel System Reliability using Multiple Response Surfaces

Zhiliang Liu,Liang Li,Guangming Yu,Jun Hu,Houlai Lin,Chunli Li,Shibao Lu,Kaiqi Meng,Jun Lei 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.2

A method of calculating the failure probability of the tunnel system combining finite element numerical simulation with multiple response surface method (MRSM) and Monte-Carlo simulation (MCS) is presented. The applicability of the proposed methodology is verified through a subway interval soft rock tunnel in Qingdao, China. The sensitivity of Monte-Carlo sampling number and coefficients of variation for rock masses on the failure probability of tunnel system is conducted. The primary failure modes in tunnel system are identified by reanalyzing the failure samples. The simulation results demonstrate that the failure probability of a tunnel system within soft upper and hard lower surrounding rock mass is mainly attributed to the soft upper part of the surrounding rock. The coefficients of variation of the elastic modulus E1 and the internal friction angle ϕ1 of the pebble layer (soft upper part) have significant effect on the failure probability. The failure probability of tunnel system increases as the coefficients of variation of E1 and ϕ1 increase. Two primary failure modes are found to contribute to the tunnel system reliability. The effect of rock bolt length L and pipe-roof thickness H on tunnel system reliability and two primary failure modes as well are investigated. The simulation results indicate that both the enhancements in L and H tend to be more effective than the enhancement in either L or H if a small target failure probability of tunnel system is expected. The supporting structures design can be performed based on the potential sets of (L, H) satisfying target failure probability.

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.

A Way of Candidate Set Selection for Epidemic Routing in Delay Tolerate Networks

Fuquan Zhang,Kaiqi Chen,Inwhee Joe,Demin Gao,Yunfei Liu 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.10

The radio propagation effect of fading or shadowing between mobile nodes has not been well considered in contact rate. One way to incorporate interference into contact rate is multiplied by probability that the infected node copies the message to the susceptible node during a contact in epidemic routing. In this paper, we develop a model to incorporate the wireless link reliability into contact rate. For application, we proposed a scheme for epidemical delay tolerate network with considering the effects based on the model. Simulation shows that proposed scheme has better performance.

Flexible Composite Materials – Between Inorganic Fibers and Organic Polymers

Guangchao Sun,Qingzhu Liu,Kaikai Si,Jiayu Zhang,Rui Xiong,Kaiqi Liu,Yunfa Chen 한국섬유공학회 2020 Fibers and polymers Vol.21 No.3

In order to develop a flexible composite material that could play a good cushion role for high temperature ceramicmembrane cleaning, we herein report a flexible composite material which could achieve effective buffering to relieve thestress generated by rigid contact and play a certain sealing effect. The coating method is applied to fabricate the compositematerial, which can be produced by multi-layer superposition using high silica fiber fabric and waterborne polyurethane. Theresults show that waterborne polyurethane (WPU) as a binder coating plays a key role in improving the strength by six timescompared to raw materials and maintaining the elasticity of materials. Meanwhile, the thermal degradation mechanism of thecomposites calcined at different temperatures (700-1200 oC) in air atmosphere is investigated. The as-made compositematerials still have good flexibility, and the tensile strength is about 2.4 MPa after calcination at 1000 oC for 80 h. Thisprovides a method to prepare flexible cushion composite materials for ceramic membrane filtration.

Analytical model for the basement wall horizontally supported by flexible floor diaphragms

Yongjun Lin,Xianzhao Zhang,Kaiqi Liu,Wenqiang Xu 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.79 No.5

Subterranean floors are treated as the rigid lateral support in the current practice for the basement wall design. The structural performance of the basement wall will be influenced by the floor openings, which are inevitable to satisfy building functional requirements. An analytical model for the basement wall being presented is able to analyze the effect of such opening quantitatively. The magnitude of the horizontal support stiffness is determined based on deformation analysis of the diaphragm opening area. Idealized models of the basement wall are continuous beams with various degrees of indeterminacy. The force method is used to deduce the functions for internal forces acting towards the basement wall. The proposed analytical model is verified with results derived by finite element analyses through consideration of various factors, including various numbers of stories, combinations of beam-slab sections, and percentages of floor opening dimensions. The maximum deviations on critical design sections for all prototype basement structures are less than 15.99%. Comparisons with conventional rigid support models are also performed, providing an estimation of the effect of the opening on the mechanical behavior of the basement wall.

Influence of the evolution of heat-resistant phases on elevated-temperature strengthening mechanism and deformation behavior in Al–Si multicomponent alloys

Meng Fanchao,Wu Yuying,Li Wenbo,Hu Kaiqi,Zhao Kai,Yang Huabing,Gao Tong,Sun Yue,Liu Xiangfa 한국물리학회 2022 Current Applied Physics Vol.39 No.-

Evolution of the heat-resistant phases and deformation behavior of α-Al matrix of four alloys have been characterized by SEM and EBSD. The strengthening mechanisms influenced by morphology and distribution of the heat-resistant phases were described. And the strain contouring of the α-Al matrix after deformation was rendered. The heat-resistant phases with block-like as reticular or semi-reticular network distribution exist in grain boundary can effectively provide elevated-temperature strength for alloys, while the strain contouring of α-Al matrix is mainly concentrated in the area with fewer intermetallic phases. It is shown that intermetallic phase evolution corresponds to extrusion treatment and the formation of eutectic Si and primary Si, highly interconnected networks of intermetallic phases exist in the alloy in which the primary Si and the eutectic Si are simultaneously present or disappeared. And only the disappearance of the primary Si and the extrusion treatment will destroy the network structure of the intermetallic phases. A reticular or semi-reticular microstructure is more capable of matching strength and plasticity and facilitating uniform deformation of the α-Al matrix. And the destruction of this microstructure is allowed to accommodate more plastic strain before failure.