Numerical Investigation and Design of Cold-formed Steel Angle Columns with Complex Edges under Axial Compression

Jun-Feng Zhang,Mengmeng Feng,En-Feng Deng,Shiyun Pang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.2

Currently, cold-formed steel (CFS) is widely used in fabricated steel structures for high strength-to-weight ratio and ease for installation. However, limited research is available in the literature on the CFS angle columns with complex edges under axial compression. In this paper, the axial compressive capacity of the CFS angle columns with complex edges was numerically studied. The distortional buckling characteristics of 1008 CFS angle sections with complex edges were analyzed by finite strip software CUFSM. Detailed non-linear finite element model (FEM) was developed based on finite element program ABAQUS and verified by comparing with test results. The verification indicated that the developed FEM could well predict the ultimate strength and failure model of the specimens. Using the validated FEM, an extensive parametric study comprised of 330 models was conducted. The influences of the specimen length, the edge ratio and the limb-width ratio of the angle section on the axial compressive capacity of CFS angle columns with complex edges were evaluated. Then an improved direct strength method (DSM) was proposed based on the existing DSM. The evaluations based on tests and FEA results showed that using the modified DSM to predict the load-bearing capacity of the CFS angle columns with complex edges was feasible.

Macrophages Promote Coal Tar Pitch Extract-induced Tumorigenesis of BEAS-2B Cells and Tumor Metastasis in Nude Mice Mediated by AP-1

Zhang, Peng,Jin, Yue-Fei,Zhang, Qiao,Wu, Yi-Ming,Wu, Wei-Dong,Yao, Wu,Wu, Yong-Jun,Li, Zhi-Tao,Zhao, Yong,Liu, Yu,Feng, Fei-Fei Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.12

Background: We sought to evaluate the role of tumor associated macrophages (TAMs) on the promotion of coal tar pitch extract (CTPE)-induced tumorigenesis of human bronchial epithelial cells (BEAS-2B) and tumor metastasis in nude mice, and related mechanisms. Materials and Methods: BEAS-2B cells were first treated with 2.4 mg/mL CTPE for 72 hours. After removal of CTPE, the cells were continuously cultured and passaged using trypsin-EDTA. THP-1 cells were used as macrophage-like cells. BEAS-2B cells under different conditions (n=6/group) were injected into the back necks of nude mice, and alterations of tumor xenograft growth, indicative of tumorigenicity, and tumor metastasis were determined. Pathological changes (tumor nests and microvascular lesions) of HE-stained tumor tissues were also evaluated. The expression of AP-1(c-Jun) in xenografts and metastatic tumors was determined using immunohistochemistry. Results: Tumor size and weight in nude mice transplanted with the mixture of CTPE-induced passage 30 BEAS-2B and THP-1 cells (2:1) were increased compared to those from the CTPE-treated BEAS-2B cells at passage 30 alone at different observation time points. Tumor metastasis to lymph nodes and liver was only detected after transplantation of a mixture the two kinds of cells. The numbers of tumor nests and microvascular lesions, and the expression levels of AP-1 (c-Jun) in tumors from the mixture of two kinds of cells were increased apparently in contrast to those in tumor from the CTPE-treated BEAS-2B cells of passage 30 alone. In addition, there was positive correlation between AP-1 (c-Jun) expression level and the number of microvascular lesions, or between AP-1 (c-Jun) expression level and tumor metastasis in these two groups. Conclusions: TAMs not only facilitate tumorigenesis transformation of CTPE-induced BEAS-2B cells, but also promote tumor growth, angiogenesis and metastasis in nude mice in vivo, which may be mediated by AP-1.

Electrochemical Preparation of TiO₂/CNT Electrodes with a TNB Electrolyte and Their Photoelectrocatalytic Effects

Feng-Jun Zhang,Ming-Liang Chen,오원춘 한국세라믹학회 2009 한국세라믹학회지 Vol.46 No.4

We investigate a method for the electrochemical preparation of titanium dioxide/carbon nanotube (TiO₂/CNT) composites involving the electroplating of Ti in a titanium n-butoxide (TNB) electrolyte into a CNT matrix. The BET surface areas of TiO₂/CNT composites decreased as electrochemical operating time increased. Changes in XRD patterns showed a typical anatase type on the TiO₂/CNT composite prepared with a CNT matrix by the electroplating method in the TNB solution. In SEM micrographs, the titanium complex particles were uniformly distributed on the CNT surface. The results of chemical elemental analysis for the TiO₂/CNT composites showed that most of the spectra for these samples produced stronger peaks for carbon and Ti metal than those of any other element. Finally, the prominent photoelectrocatalytic (PEC) activities of the TiO₂/CNT composites could be attributed to the combined effects of photodegradation of TiO₂, electron assistance of CNT and the application of a sufficient voltage.

Effects of stiffening rings on the dynamic properties of hyperboloidal cooling towers

Jun-Feng Zhang,Huai Chen,Yao-Jun Ge,Lin Zhao,Shi-Tang Ke 국제구조공학회 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.49 No.5

As hyperboloidal cooling towers (HCTs) growing larger and slender, they become more sensitive to gust wind. To improve the dynamic properties of HCTs and to improve the wind resistance capability, stiffening rings have been studied and applied. Although there have been some findings, the influence mechanism of stiffening rings on the dynamic properties is still not fully understood. Based on some fundamental perceptions on the dynamic properties of HCTs and free ring structures, a concept named “participation degree” of stiffening rings was proposed and the influence mechanism on the dynamic properties was illustrated. The “participation degree” is determined by the modal deform amplitude and latitude wave number of stiffening rings. Larger modal deform amplitude and more latitude waves can both result in higher participation degree and more improvement to eigenfrequencies. Also, this concept can explain and associate the pre-existing independent findings.

Experimental and Numerical Research on Process Formability in Magnetic Pulse Forming of AZ31 Magnesium Alloy Sheets

Jun-Rui Xu,Jun-Jia Cui,Guangyong Sun,Yan-Rong Li,Chun-Feng Li 한국정밀공학회 2015 International Journal of Precision Engineering and Vol. No.

The plain strain of AZ31 magnesium alloy sheet in magnetic pulse forming was investigated by numerical simulation and experimental method. Combination of uniform pressure coil and Holmberg's specimen was employed to evaluate the plain strain of AZ31 sheet. The numerical simulation for magnetic pulse plain strain of AZ31 sheet is performed by means of ANSYS FEA software. The magnetic flux density of uniform pressure coil was distributed uniformly, especially at the center of gauged area of AZ31 sheet directly in relation to the deformation behavior of AZ31 sheet. The velocity of typical point increases as increasing energy, and the more position closes to the center of sheet the higher velocity achieves. The forming height is increased with increasing discharge voltage. Compared with C=768 μF and C=1536 μF, the capacitance of 1152 μF is more effective for forming, which is confirmed by experiments. The peak velocity at the center of sheet is about 105 m/s. The major strains of magnetic pulse plane strain lie approximately in the strain ranges of 5.83-6.45%. However, the 3.22-3.82% (major strain) are the limit strains in quasi-static condition. The experimental results indicate that the major strain of AZ31 sheet improves about 75% compared with the quasi-static case.

Protective efficacy of a high-growth reassortant swine H3N2 inactivated vaccine constructed by reverse genetic manipulation

Feng Wen,Ji-Hong Ma,Hai Yu,Fu-Ru Yang,Meng Huang,Yan-Jun Zhou,Ze-Jun Li,Guangzhi Tong 대한수의학회 2014 JOURNAL OF VETERINARY SCIENCE Vol.15 No.3

Novel reassortant H3N2 swine influenza viruses (SwIV)with the matrix gene from the 2009 H1N1 pandemic virushave been isolated in many countries as well as duringoutbreaks in multiple states in the United States, indicatingthat H3N2 SwIV might be a potential threat to public health. Since southern China is the world’s largest producer of pigs,efficient vaccines should be developed to prevent pigs fromacquiring H3N2 subtype SwIV infections, and thus limit thepossibility of SwIV infection at agricultural fairs. In thisstudy, a high-growth reassortant virus (GD/PR8) wasgenerated by plasmid-based reverse genetics and tested as acandidate inactivated vaccine. The protective efficacy of thisvaccine was evaluated in mice by challenging them withanother H3N2 SwIV isolate [A/Swine/Heilongjiang/1/05(H3N2) (HLJ/05)]. Prime and booster inoculation withGD/PR8 vaccine yielded high-titer serum hemagglutinationinhibiting antibodies and IgG antibodies. Completeprotection of mice against H3N2 SwIV was observed, withsignificantly reduced lung lesion and viral loads invaccine-inoculated mice relative to mock-vaccinatedcontrols. These results suggest that the GD/PR8 vaccine mayserve as a promising candidate for rapid intervention ofH3N2 SwIV outbreaks in China.

A Delay-aware Application Protocol for Wireless Sensor Networks

Jun-feng Gao,Hong-guo Zhang,Guang-yi Tang 보안공학연구지원센터 2015 International Journal of Grid and Distributed Comp Vol.8 No.6

Recent advances in micro electro mechanical systems (MEMS), wireless communication, and network technology, wireless sensor networks (WSNs) have become technically and economically feasible. In most case, WSNs are usually applied to many applications that require unattended operation. However unlike traditional networks, WSNs are resource constrained distributed networks. The delay latency, uncertainty and dynamic reliability of the WSNs may strongly impact on the WSNs applications. The information content or meaning of sending and receiving data will happened frequency when exchanging data among these sensor nodes over the WSNs. In addition, the application protocol themselves for data exchange may also impact on the WSNs applications. An inappropriate protocol will result in serious inefficiency so as not to meet application requirement. In order to ensure the reliability, integrity, and the continuity of data operations on the WSNs, this paper presents a delay-aware application protocol for WSNs applications. This protocol is based on ZigBee protocol that is suited for remotely monitor and control because of its low-power. Simulation results show that the protocol is feasible for the wireless sensor network in terms of the reliability, integrity and continuity of data.

Formation of Magnetic Graphene Nanosheets for Rapid Enrichment and Separation of Methyl Orange from Water

Feng-Jun Zhang,Zhuo Zhang,Han Xuan,Hong-Chen Xia,Lei Zhu,오원춘,Fazhi Xie 한국세라믹학회 2014 한국세라믹학회지 Vol.51 No.6

Magnetic-graphene nanosheets have been synthesized via a simple effective chemical precipitation method followed by heattreatment. The composite nanosheets are super paramagnetic at room temperature and can be separated by an external magneticfield. The prepared magnetic-graphene nanosheets were characterized by X-ray diffraction (XRD), scanning electron microscopy(SEM), transmission electron microscopy (TEM), Raman spectroscopy, and BET surface area analysis. The resultsdemonstrated the successful attachment of iron oxide nanoparticles to graphene nanosheets. It was found that the attachednanoparticles were mainly Fe3O4. The magnetic-graphene nanosheets showed near complete methyl orange removal within 10mintues and would be practically usable for methyl orange separation from water.

Growth and fixed points of meromorphic solutions of higher-order linear differential equations

Jun-Feng Xu,Hong-Xun Yi 대한수학회 2009 대한수학회지 Vol.46 No.4

In this paper, we investigate the growth and fixed points of meromorphic solutions of higher order linear differential equations with meromorphic coefficients and their derivatives. Because of the restriction of differential equations, we obtain that the properties of fixed points of meromorphic solutions of higher order linear differential equations with meromorphic coefficients and their derivatives are more interesting than that of general transcendental meromorphic functions. Our results extend the previous results due to M. Frei, M. Ozawa, G. Gundersen, and J. K. Langley and Z. Chen and K. Shon. In this paper, we investigate the growth and fixed points of meromorphic solutions of higher order linear differential equations with meromorphic coefficients and their derivatives. Because of the restriction of differential equations, we obtain that the properties of fixed points of meromorphic solutions of higher order linear differential equations with meromorphic coefficients and their derivatives are more interesting than that of general transcendental meromorphic functions. Our results extend the previous results due to M. Frei, M. Ozawa, G. Gundersen, and J. K. Langley and Z. Chen and K. Shon.

Expression patterns of octoploid strawberry TGA genes reveal a potential role in response to Podosphaera aphanis infection

Jun Feng,Yang Cheng,Caixia Zheng 한국식물생명공학회 2020 Plant biotechnology reports Vol.14 No.1

TGA family transcription factors are downstream components of the salicylic acid (SA) pathway and play a crucial role in the penetration defense against powdery mildew, a disease caused by the biotrophic pathogen Podosphaera aphanis that can cause enormous financial losses. However, the TGA genes in the octoploid strawberry (Benihoppe) remain largely unexplored. In this study, 11 FaTGA genes were identified and grouped into five subgroups based on the Strawberry GARDEN database. The evolution of TGAs has been relatively conservative, maintaining nearly the same protein domain and motif architectures. RT-qPCR showed that FaTGA s have different expression patterns in roots, stems, and leaves. The characteristics of their gene expression patterns indicate that FaTGA1, FaTGA2, FaTGA5, FaTGA7, FaTGA8, FaTGA9, and FaTGA10, as well as SA-responsive genes, were responsive to P. aphanis infection. In particular, exogenous SA induced significant upregulation of FaTGA and SA-responsive genes. Further correlation analysis suggested that FaTGA1, FaTGA2, FaTGA5, FaTGA7, FaTGA8, and FaTGA10 may play a crucial role in the response to powdery mildew disease. Taken together, our results reveal the responses of TGA genes in the strawberry P. aphanis interaction, which will provide further insight into the strawberry defense against powdery mildew.