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Static and Cyclic Tension Behavior of Post-Installed Rebar after Exposure to High Temperature
Qun Xie,Song Xue,Yongqiang Zhao 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.6
In order to investigate the static and cyclic tension behavior of post-installed rebar along with cement-based adhesive that is adopted after exposure to high temperature, a three-phase experimental program has been carried out and two typical embedment depths, 10d and 15dare designed. The surfaces of specimens are firstly heated up to 800oC, and then the residual strength at different temperatures of cement-based adhesive has been studied by consequent static pull-out tests. Experimental results show that the tensile strength has a significant reduction at elevated temperatures compared with that of room temperature. The cement-based adhesive has almost lost its full bond strength when the temperature exceeds 350oC. Finally, the bond performance of cement-based adhesive under cyclic loading has been further tested and analyzed. It is found that both 10d and 15d specimens have failed abruptly with rebar pull-out. The employment of long embedment depth has been verified to be an effective method to improve the bond performance of cement-based adhesive under static and cyclic loading. Static numerical investigation indicates that the bond stress distribution is not uniform along the embedment length of post-installed rebar at different temperatures of cement-based adhesive. The temperature-dependent tensile strength prediction has also been obtained based on the experimental data.
Qun He,Michael C. H. Yam,Zhiyang Xie,Xue-Mei Lin,Kwok-Fai Chung 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.44 No.4
In this study, the classical J2 flow theory is explicitly proved to be inappropriate to describe the plastic behaviour of structural steels under different stress states according to the reported test results. A numerical framework of the characterization of the strain hardening and ductile fracture initiation involving the effect of stress states, i.e., stress triaxiality and Lode angle parameter, is proposed based on the mechanical response of structural steels under monotonic loading. Both effects on strain hardening are determined by correction functions, which are implemented as different modules in the numerical framework. Thus, other users can easily modify them according to their test results. Besides, the ductile fracture initiation is determined by a fracture locus in the space of stress triaxiality, Lode angle parameter, and fracture strain. The numerical implementation of the proposed model and the corresponding code are provided in this paper, which are also available on GitHub. The validity of the numerical procedure is examined through single element tests and the accuracy of the proposed model is verified by existing test results.
Qun Wei,Lei Xu,Zhimeng Tang,Zhangbiao Xu,Cheng Xie,Lirong Guo,Wei Li 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.122 No.-
Herein, a facile preparation method with characteristics of energy-saving, efficient and environmentallyfriendly is proposed. Firstly, GICs (Graphite Intercalation Compounds) were synthesized by microwaveassisted hydrothermal method using flake graphite (FG) as raw material, H2SO4, and K2S2O8 as oxidativeintercalations by microwave-assisted oxidation for 5 min, and then EG was prepared from obtained GICsby microwave irradiation for 40 s under the microwave power of 800 W, and the effect of different processconditions on EG expansion volume (EV) was studied. The results show that EG with a good expansioncan be rapidly prepared by microwave irradiation, and the EV value can reach 455 mL /g under theoptimal conditions. In particular, the prepared EG has a high graphitization degree with less structuraldamage, exihibiting good industrial application prospects. The mechanism of K2S2O8 oxidation and graphiteexpansion under microwave irradiation was analyzed. In adition, flexible graphite foil papers preparedwith the obtained EG exhibit good electrical conductivity and thermal properties. The as preparedEG material shows an efficient adsorption of hydraulic oil and vegetable oil and excellent flame retardantperformance. This preparation method is green, low cost, and safe, and can be used for the efficient batchpreparation of EG.
Investigation on low velocity impact on a foam core composite sandwich panel
Zonghong Xie,Qun Yan,Xiang Li 국제구조공학회 2014 Steel and Composite Structures, An International J Vol.17 No.2
A finite element model with the consideration of damage initiation and evolution has been developed for the analysis of the dynamic response of a composite sandwich panel subject to low velocity impact. Typical damage modes including fiber breakage, matrix crushing and cracking, delamination and core crushing are considered in this model. Strain-based Hashin failure criteria with stiffness degradation mechanism are used in predicting the initiation and evolution of intra-laminar damage modes by self-developed VUMAT subroutine. Zero-thickness cohesive elements are adopted along the interface regions between the facesheets and the foam core to simulate the initiation and propagation of delamination. A crushable foam core model with volumetric hardening rule is used to simulate the mechanical behavior of foam core material at the plastic state. The time history curves of contact force and the core collapse area are obtained. They all show a good correlation with the experimental data.
( Yue Qun Wang ),( Xiang Li Ye ),( Jun Mei Zhou ),( Yong Qi Wan ),( Hua Ping Xie ),( Yun Deng ),( Yan Yan ),( Yong Qing Li ),( Xiong Wei Fan ),( Wu Zhou Yuan ),( Xiao Yang Mo ),( Xiu Shan Wu ) 생화학분자생물학회(구 한국생화학분자생물학회) 2011 BMB Reports Vol.44 No.1
Zinc finger (ZNF) proteins play a critical role in cell growth, proliferation, apoptosis, and intracellular signal transduction. In this paper, we cloned and characterized a novel human KRAB-related zinc finger gene, ZNF425, which encodes a protein of 752 amino acids. ZNF425 is strongly expressed in the three month old human embryos and then is almost undetectable in six month old embryos and in adult tissues. An EGFP-ZNF425 fusion protein can be found in both the nucleus and the cytoplasm. ZNF425 appears to act as a transcription repressor. Over-expression of ZNF425 inhibits the transcriptional activities of SRE, AP-1, and SRF. Deletion analysis indicates that the C2H2 domain is the main region responsible for the repression. Our results suggest that the ZNF425 gene is a new transcriptional inhibitor that functions in the MAPK signaling pathway. [BMB reports 2011; 44(1): 58-63]
( Yan Qun Hu ),( Li Li Chen ),( Chuan Wang ),( Ya Feng Xie ),( Zhi Xi Chen ),( Liang Zhuan Liu ),( Ze Hong Su ),( Yi Mou Wu ) 한국미생물 · 생명공학회 2015 Journal of microbiology and biotechnology Vol.25 No.8
Chlamydophila psittaci is an important intracellular pathogen. Persistent infection is an important state of the host-parasite interaction in this chlamydial infection, which plays a significant role in spreading the organism within animal populations and in causing chronic chlamydiosis and serious sequelae. In this study, a C. psittaci persistent infection cell model was induced by penicillin G, and real-time quantitative PCR was used to study the transcriptional levels of 10 C. psittaci genes (dnaA, dnaK, ftsW, ftsY, grpE, rpsD, incC, omcB, CPSIT_0846, and CPSIT_0042) in acute and penicillin-G-induced persistent infection cultures. Compared with the acute cultures, the penicillin-G-treated cultures showed a reduced chlamydial inclusion size and a significantly decreased number of elementary body particles. Additionally, some enlarged aberrant reticulate body particles were present in the penicillin- G-treated cultures but not the acute ones. The expression levels of genes encoding products for cell division (FtsW, FtsY) and outer membrane protein E encoding gene (CPSIT_0042) were downregulated (p < 0.05) from 6 h post-infection onward in the persistent infection cultures. Also from 6 h post-infection, the expression levels of DnaA, DnaK, IncC, RpsD, GrpE, and CPSIT_0846 were upregulated (p < 0.05); however, the expression level of OmcB in the persistent infection was almost the same as that in the acute infection (p > 0.05). These results provide new insight regarding molecular activities that accompany persistence of C. psittaci, which may play important roles in the pathogenesis of C. psittaci infection.
Nanhong Tang,Qun Xie,Xiaoqian Wang,Xiujin Li,Yanlin Chen,Xu Lin,Jianyin Lin 대한약학회 2011 Archives of Pharmacal Research Vol.34 No.5
Snake venom cystatin (sv-cystatin) is a member of the cystatin family of cysteine protease inhibitors. To further evaluate the possibility of sv-cystatin in cancer therapy, this study examined the effects of sv-cystatin on the invasion and metastasis of liver cancer cells (MHCC97H) in vitro and in vivo as well as the underlying mechanism. sv-cystatin cDNA was transfected into MHCC97H cells and the anti-invasion and antimetastasis effects of sv-cystatin were determined using migration and matrigel invasion assays and a lung-metastasis mice model. The results suggest that sv-cyst clone (sv-cystatin expression in MHCC97H cells) delayed the invasion and metastasis in vitro and in vivo compared to the parental, mock and si-sv-cyst clone cells (inhibited sv-cystatin expression by siRNA). The decreased activities of cathepsin B, MMP-2 and MMP-9 and EMT change index including higher E-cadherin, lower N-cadherin and decreased Twist activity were observed in the sv-cyst clone, which contributes to the change in invasion and metastasis ability of MHCC97H cells. This study provides evidence that expression of the sv-cystatin gene in MHCC97H cells inhibits tumor cell invasion and metastasis through the reduction of the proteinases activity and Epithelial-Mesenchymal Transition (EMT), which might contribute to the anticancer research of the sv-cystatin protein.
Systemic Analysis on Risk Factors for Breast Cancer Related Lymphedema
Zhu, Ya-Qun,Xie, Yu-Huan,Liu, Feng-Huan,Guo, Qi,Shen, Pei-Pei,Tian, Ye Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.16
Background: To evaluate risk factors for upper extremity lymphedema due to breast cancer surgery. Materials and Methods: Clinical studies published on PubMed, Ovid, EMbase, and Cochrane Library from January 1996 to December 2012 were selected. Results: Twenty-five studies were identified, including 12,104 patients. Six risk factors related to the incidence of lymphedema after breast cancer treatment were detected: axillary lymph node dissection (OR=3.73, 95%CI 1.16 to 11.96), postoperative complications (OR=2.64, 95%CI 1.10 to 6.30), hypertension (OR=1.83, 95%CI 1.38 to 2.42), high body mass index (OR=1.80, 95%CI 1.30 to 2.49), chemotherapy (OR=1.38, 95%CI 1.07 to 1.79) and radiotherapy (OR=1.35, 95%CI 1.10 to 1.66). We found significant protective factors for lymphedema: pathologic T classification (OR=0.57, 95%CI 0.36 to 0.91) and stage (OR=0.60, 95%CI 0.39 to 0.93), while some factors, like age, number of positive lymph nodes, number of lymph node dissection, demonstrated no obvious correlation. Conclusions: Axillary lymph node dissection, postoperative complications, hypertension, body mass index, chemotherapy, radiotherapy are risk factors for lymphedema after breast cancer treatment. Attention should be paid to patients with risk factors to prevent the occurrence of lymphedema.