Experimental study on through-beam connection system for concrete filled steel tube column-RC beam

Chunyu Tian,Congzhen Xiao,Tao Chen,Xueyi Fu 국제구조공학회 2014 Steel and Composite Structures, An International J Vol.16 No.2

A new through-beam connection system for a concrete filled steel tube column to RC beam is proposed. In this connection, there are openings on the steel tube while the reinforced concrete beams are continuous in the joint zone. The moment and shear force at the beam ends can be transferred to column by continuous rebar and concrete. The weakening of the axial load and shear bearing capacity due to the opening of the steel tube can be compensated by strengthening steel tube at joint zone. Using this connection, construction of the joint can be made more convenient since welding and hole drilling in situ can be avoided. Axial compression and reversed cyclic loading tests on specimens were carried out to evaluate performance of the new beam-column connection. Load-deflection performance, typical failure modes, stress and strain distributions, and the energy dissipation capacity were obtained. The experimental results showed that the new connection have good bearing capacity, superior ductility and energy dissipation capacity by effectively strengthen the steel tube at joint zone. According to the test and analysis results, some suggestions were proposed to design method of this new connection.

Synergistic Effect of PVA Fiber and PTB Emulsion on Mechanical Properties of Cementitious Composites for Damage Repair in Operating Tunnels

Chunyu Zhang,Mengjun Chen,Rentai Liu,Xiuhao Li,Jia Yan,Zhijing Zhu,Fengshuai Fan 대한토목학회 2022 KSCE Journal of Civil Engineering Vol.26 No.12

Operating tunnels are often located in complex geological conditions and are prone to various types of damage. Even after structural repair, the repaired material may be vulnerable to secondary damage. It is difficult to effectively repair operating tunnel damage. Hence, developing high-performance repair materials for tunnel structures is critical. This study aimed to develop repair materials by studying the synergistic effects of fiber and polymers. The effectof polyvinyl alcohol (PVA) fiber and PTB (COMPAKTUNA.PRO) emulsion on the compressive strength (40 × 40 × 40 mm, GB/T 17671-2020), flexural strength (40 × 40 × 160 mm, GB/T 17671-2020), uniaxial tensile properties (330 × 60 × 13 mm, JC/T 2461-2018), bond strength (40 × 40 × 160 mm, JC/T 2537-2019), rapid chloride migration coefficient (ϕ100 × 50 mm, GB/T 50082-2009), porosity (40 × 40 × 40 mm, SY/T 6490-2014), and scanning electron microscopy (less than 1 cm3, GB/T 27788-2020) was analysed. The test was completed in the laboratory of our school, and the average value of three specimens per mix ratio was taken. The results indicate that both PVA fiber and PTB emulsion addition reduce the compressive strength but significantly increase the flexural strength, tensile strength, and ultimate tensile strain of cementitious composite. The compressive-to-flexural strength ratio decreases, and the uniaxial compression toughness index increases. The cementitious composites exhibit good integrity after damage. The influence of the PVA fiber is more potent than that of the PTB emulsion. The PTB emulsion increases the impermeability and bonding strength of the cementitious composite and can improve the disadvantages caused by adding the PVA fibers. The bridging effect of the PVA fiber and the membrane-forming effect of the PTB emulsion together influence the performance and cause a synergistic effect to achieve superposition and complementation of advantages. The optimal content of the PVA fiber and PTB emulsion under the synergistic effect can be obtained. The findings can provide a theoretical basis for the optimal design and practical application of restoration materials.

IL-17A Secreted by Th17 Cells Is Essential for the Host against Streptococcus agalactiae Infections

( Jing Chen ),( Siyu Yang ),( Wanyu Li ),( Wei Yu ),( Zhaowei Fan ),( Mengyao Wang ),( Zhenyue Feng ),( Chunyu Tong ),( Baifen Song ),( Jinzhu Ma ),( Yudong Cui ) 한국미생물생명공학회(구 한국산업미생물학회) 2021 Journal of microbiology and biotechnology Vol.31 No.5

Streptococcus agalactiae is an important bacterial pathogen and causative agent of diseases including neonatal sepsis and meningitis, as well as infections in healthy adults and pregnant women. Although antibiotic treatments effectively relieve symptoms, the emergence and transmission of multidrug-resistant strains indicate the need for an effective immunotherapy. Effector T helper (Th) 17 cells are a relatively newly discovered subpopulation of helper CD4⁺ T lymphocytes, and which, by expressing interleukin (IL)-17A, play crucial roles in host defenses against a variety of pathogens, including bacteria and viruses. However, whether S. agalactiae infection can induce the differentiation of CD4⁺ T cells into Th17 cells, and whether IL-17A can play an effective role against S. agalactiae infections, are still unclear. In this study, we analyzed the responses of CD4⁺ T cells and their defensive effects after S. agalactiae infection. The results showed that S. agalactiae infection induces not only the formation of Th1 cells expressing interferon (IFN)-γ, but also the differentiation of mouse splenic CD4⁺ T cells into Th17 cells, which highly express IL-17A. In addition, the bacterial load of S. agalactiae was significantly increased and decreased in organs as determined by antibody neutralization and IL-17A addition experiments, respectively. The results confirmed that IL-17A is required by the host to defend against S. agalactiae and that it plays an important role in effectively eliminating S. agalactiae. Our findings therefore prompt us to adopt effective methods to regulate the expression of IL-17A as a potent strategy for the prevention and treatment of S. agalactiae infection.

Functional Roles of Exosomes in Allergic Contact Dermatitis

Song Bocui,Chen Qian,Li Yuqi,Zhan Shuang,Zhao Rui,Shen Xue,Liu Min,Tong Chunyu 한국미생물·생명공학회 2022 Journal of microbiology and biotechnology Vol.32 No.12

Allergic contact dermatitis (ACD) is an allergen-specific T-cell-mediated inflammatory response, albeit with unclear pathogenesis. Exosomes are nanoscale extracellular vesicles secreted by several cell types and widely distributed in various biological fluids. Exosomes affect the occurrence and development of ACD through immunoregulation among other ways. Nevertheless, the role of exosomes in ACD warrants further clarification. This review examines the progress of research into exosomes and their involvement in the pathogenesis, diagnosis, and treatment of ACD and provides ideas for exploring new diagnostic and treatment methods for this disease.

A Novel Distributed Clustering-based MDS Algorithm for Nodes Localization in WSNs

Guoyong Dai,Chunyu Miao,Yidong Li,Keji Mao,Qingzhang Chen 보안공학연구지원센터 2015 International Journal of Grid and Distributed Comp Vol.8 No.2

Localization of sensors nodes is a key and fundamental issue in wireless sensor networks due to random deployment. In this paper, we propose a tree based clustering (TBC) multidimensional scaling algorithm for wireless sensor networks with the purpose of overcoming the shortage of classical MDS algorithms in its localization accuracy and computing complexity. Clustering is adopted to degrade the problem scale in our approach and a moderate number of common nodes between clusters are kept during clustering. Inner cluster local coordinates are calculated and then mapped into global coordinates according to the tree structure formed by clustering. Simulations on MATLAB are conducted and the results show that the proposed algorithm has better localization coverage and higher accuracy than the traditional MDS based algorithms.

Feedback Analysis of Transcutaneous Energy Transmission with a Variable Load Parameter

Tianliang Yang,Chunyu Zhao,Dayue Chen 한국전자통신연구원 2010 ETRI Journal Vol.32 No.4

The transcutaneous energy transmission system (TETS) composed of a Class-E amplifier may operate at a state away from the optimum power transmission due to the load variation. By introducing the feedback-loop technique, the TETS can keep the optimum state with constant output voltage by adjusting the important design parameters, that is, the duty ratio and frequency of the driving signal and the supply voltage. The relations between these adjusted parameters and the load are investigated. The effectiveness of the feedback technique is validated through a design example with a variable load parameter. The experimental results show that the Class-E amplifier in the feedback loop can keep operating at the optimum state under the condition of up to 50 percent variation of the load value.

Weak fault detection method of rolling bearing based on testing signal far away from fault source

Zhiyuan He,Guo Chen,Tengfei Hao,Chunyu Teng,Minli Hou,Zhenjie Chen 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.3

In some cases, because of the complex internal structure of the machines, the positions of the vibration sensors are far away from the rolling bearings, such as in an aeroengine, causing the fault features to become extremely weak, which brings great challenge to the detection of rolling bearings. To address this problem, an integrated detection method is proposed. First, a method named MEDL is proposed to determine the optimal filter length in minimum entropy deconvolution (MED) to enhance the periodic fault impulse component in the weak signal, which accuracy is 1. After that, the MEDL is combined with variational mode decomposition (VMD) and autocorrelation to extract fault features from strong background noise. A series of fault simulation experiments for rolling bearings were conducted by using an aeroengine rotor experimental rig with casing. The results verify that the accuracy of the integrated detection method is 100 % in different measuring points, speeds and fault types. At the same time, it compared with spectral kurtosis (SK) and empirical wavelet transform (EWT). It proves that the integrated detection method is more robust in extracting the weak fault characteristic of rolling bearings from the casing signals effectively.

Supramolecular assembled three-dimensional graphene hybrids: Synthesis and applications in supercapacitors

Ni, Lubin,Zhang, Wang,Wu, Zhen,Sun, Chunyu,Cai, Yin,Yang, Guang,Chen, Ming,Piao, Yuanzhe,Diao, Guowang Elsevier 2017 APPLIED SURFACE SCIENCE - Vol.396 No.-

<P><B>Abstract</B></P> <P>Graphene-based materials have received worldwide attention in the focus of forefront energy storage investigations. Currently, the design of novel three-dimensional (3D) graphene structures with high energy capability, superior electron and ion conductivity, and robust mechanical flexibility is still a great challenge. Herein, we have successfully demonstrated a novel approach to fabricate 3D assembled graphene through the supramolecular interactions of β-cyclodextrin polymers (β-CDP) with an adamantine end-capped poly(ethylene oxide) polymer linker (PEG-AD). The incorporation of PEG-AD linker into rGO sheets increased the interlayer spacing of rGO sheets to form 3D graphene materials, which can provide efficient 3D electron transfer pathways and ion diffusion channels, and facilitate the infiltration of gel electrolyte. The as-prepared 3D self-assembled graphene materials exhibit significantly improved electrochemical performances of supercapacitor in terms of high specific capacitance, remarkable rate capability, and excellent cycling stability compared to pristine reduced graphene oxide. This study shed new lights to the construction of three dimensional self-assembled graphene materials and their urgent applications in energy storage.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Supramolecular assembled three-Dimensional (3D) graphene was first fabricated by host-guest interactions of β-CDPs with PEG-AD linkers. </LI> <LI> The incorporation of PEG-AD linker into rGO sheets can provide efficient 3D electron transfer pathways and ion diffusion channels. </LI> <LI> The 3D self-assembled graphene exhibits high specific capacitance, remarkable rate capability, and excellent cycling stability. </LI> <LI> This study shed new lights to design 3D self-assembled graphene materials and their urgent applications in energy storage. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Supramolecular assembled three-dimensdional graphene-based architectures were built by host-guest interactions of β-cyclodextrin polymers(β-CDPs) with adamantine end-capped poly(ethylene oxide) polymer linker (PEG-AD), exhibit significantly improved electrochemical performances of supercapacitor in terms of high specific capacitance, remarkable rate capability, and excellent cycling stability compared to pristine reduced graphene oxide.</P> <P>[DISPLAY OMISSION]</P>

Phosphonitrogenated methyl epoxyoleate as sustainable bio-based lubricating additive for paraffin oil and vegetable oil

Fangfang Jie,Mingjia Liao,Siwei Jiang,Chunyu Song,Chengli Tang,Boshui Chen 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.12

Phosphonation and nitrogenation of methyl epoxyoleate (MEO) were done to prepare phosphonitrogenated methyl epoxyoleate (PNMEO). The structural characteristics of PNMEO were characterized. The tribological properties of PNMEO and MEO as additives in a paraffin oil and a rapeseed oil were evaluated, and the morphologies, element compositions and tribochemical species of worn surfaces were analyzed. Results showed that PNMEO was more efficient in enhancing tribological properties of oils than MEO. Results also showed that PNMEO and MEO were more powerful in paraffin oil than in rapeseed oil in improving loadcarrying, friction-reducing and anti-wear performances, but in rapeseed oil than in paraffin oil in improving extreme pressure property. The tribological mechanisms of PNMEO in reducing friction and wear were attributed to PNMEO-involved tribo-adsorptions and tribo-reactions to produce a composite boundary lubrication film which consisted of a matrix of PNMEO with inclusions of iron oxide, polyphosphates, aminic compounds, and the base oil molecules.

Involvement of Orai1 in tunicamycin-induced endothelial dysfunction

Hui Yang,Yumei Xue,Sujuan Kuang,Mengzhen Zhang,Jinghui Chen,Lin Liu,Zhixin Shan,Qiuxiong Lin,Xiaohong Li,Min Yang,Hui Zhou,Fang Rao,Chunyu Deng 대한약리학회 2019 The Korean Journal of Physiology & Pharmacology Vol.23 No.2

Endoplasmic reticulum (ER) stress is mediated by disturbance of Ca2+ homeostasis. The store-operated calcium (SOC) channel is the primary Ca2+ channel in non-excitable cells, but its participation in agent-induced ER stress is not clear. In this study, the effects of tunicamycin on Ca2+ influx in human umbilical vein endothelial cells (HUVECs) were observed with the fluorescent probe Fluo-4 AM. The effect of tunicamycin on the expression of the unfolded protein response (UPR)-related proteins BiP and CHOP was assayed by western blotting with or without inhibition of Orai1. Tunicamycin induced endothelial dysfunction by activating ER stress. Orai1 expression and the influx of extracellular Ca2+ in HUVECs were both upregulated during ER stress. The SOC channel inhibitor SKF96365 reversed tunicamycin-induced endothelial cell dysfunction by inhibiting ER stress. Regulation of tunicamycin-induced ER stress by Orai1 indicates that modification of Orai1 activity may have therapeutic value for conditions with ER stress-induced endothelial dysfunction.