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Zhong Fu Wang,Handong Liu,Riyun Li,Yunfeng Fang,Dan Bi 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.9
This paper geologically analyzed and numerically simulated the rock avalanche which happened in Pusa Village, Zhangjiawan Town, Nayong County, Guizhou Province, China on 28 August 2017, with approximately 5 × 105 m3 of failure mass. The features, dynamic processand evolution mechanism of the Pusa avalanche, based on the detailed field geological survey, UAV photography and monitoring video, was analyzed in detail, and the numerical model was established to simulate the initiation-movement-accumulation process. The results show that the rock avalanche originated basically from the limestone and siltstone of Yelong Formation, Triassic which extend approximately horizontally and possess developed dissolution and subsidence. The joints within such strata have progressively evolved into fissure belt and subsidence belt resulting from long-term weathering, and the steep joints parallel to slope surface were developed due to the tectonic and unloading actions. The slope deformed and fractured because of long-term gravity and weathering actions, and meanwhile the rainstorm and mining activity accelerated the deformation of slope, which finally resulted in the overall instability of slope. The in-depth analysis to the generation and disaster-induced mechanism of Pusa avalanche is of great importance to the prevention of such accidents.
InSAR Studies of Alaska Volcanoes
Zhong Lu,Chuck Wicks,Dan Dzurisin,John Power 大韓遠隔探査學會 2005 大韓遠隔探査學會誌 Vol.21 No.1
Interferometric synthetic aperture radar (InSAR) is a remote sensing technique capable of measuring ground surface deformation with sub-centimeter precision and spatial resolution in tens-of-meters over a large region. This paper describes basics of InSAR and highlights our studies of Alaskan volcanoes with InSAR images acquired from European ERS-1 and ERS-2, Canadian Radarsat-1, and Japanese JERS-1 satellites.
Zhong Li,Dawei Zheng,Feng Hong,Dan Ni 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.1
Cavitating flow over a two-dimensional Clark-Y hydrofoil is numerically investigated via a Modified density correction method (MDCM) for turbulence closure to improve the capability of two-phase flow simulation for the k-ε RNG turbulence model. A transport equation model for the local volume fraction of vapor is solved, and a modified version of the Kunz model is used for the condensation and evaporation processes. Simulations have been conducted for various cavitation numbers ranging from non-cavitating to cloud cavitation. We compared the time-averaged lift and drag coefficients, cavitation dynamics, and time-averaged velocity profiles with the available experimental data for the MDCM and Density correction method (DCM). The comparisons between numerical and experimental results show that the MDCM and DCM are capable of capturing the special trends of the lift coefficient at the inception cavitation stage and the drag coefficient at the cloud cavitation stage. The MDCM is more robust and physical than the DCM in predicting the wake flow downstream from the trailing edge. The predicted attached cavities of both models almost show the same trend near the leading edge of the hydrofoil. However, the MDCM predicts more shedding cavity than the DCM in the wake region.
Characterizing the strain transfer on the sensing cable-soil interface based on triaxial testing
Dan Zhang,Guan-Zhong Wu,Tai-Song Shan,Bin Shi,Yuan-Jiang Fang,Kang Ren 국제구조공학회 2022 Smart Structures and Systems, An International Jou Vol.30 No.1
The deformation coordination between a rock/soil mass and an optical sensing cable is an important issue for accurate deformation monitoring. A stress-controlled triaxial apparatus was retrofitted by introducing an optical fiber into the soil specimen. High spatial resolution optical frequency domain reflectometry (OFDR) was used for monitoring the strain distribution along the axial direction of the specimen. The results were compared with those measured by a displacement meter. The strain measured by the optical sensing cable has a good linear relationship with the strain calculated by the displacement meter for different confining pressures, which indicates that distributed optical fiber sensing technology is feasible for soil deformation monitoring. The performance of deformation coordination between the sensing cable and the soil during unloading is higher than that during loading based on the strain transfer coefficients. Three hypothetical strain distributions of the triaxial specimen are proposed, based on which theoretical models of the strain transfer coefficients are established. It appears that the parabolic distribution of specimen strain should be more reasonable by comparison. Nevertheless, the strain transfer coefficients obtained by the theoretical models are higher than the measured coefficients. On this basis, a strain transfer model considering slippage at the interface of the sensing cable and the soil is discussed.
Dan Zong,Li Yin,Qian Zhong,Wen-jie Guo,Jian-hua Xu,Ning Jiang,Zhi-rui Lin,Man-zhi Li,Ping Han,Lin Xu,Xia He,Mu-sheng Zeng 대한암학회 2016 Cancer Research and Treatment Vol.48 No.1
Purpose The purpose of this study was to investigate the function of Zinc finger protein 488 (ZNF488) in nasopharyngeal carcinoma (NPC). Materials and Methods The endogenous expression of ZNF488 in NPC tissues, normal nasopharyngeal epithelium tissues and NPC cell lines were detected by quantitative reverse transcription polymerase chain reaction. ZNF488 over-expressing and knock-down NPC cell line models were estab- lished through retroviral vector pMSCV mediated over-expression and small interfering RNA (siRNA) mediated knock-down. The invasion and migration capacities were evaluated by wound healing and transwell invasion assays in ZNF488 over-expressing and control cell lines. Soft-agar colony formation and a xenograft experiment were performed to study tumorigenic ability in vitro and in vivo. Immunofluorescence and western blotting analysis were used to examine protein changes followed by ZNF488 over-expression. Microarray analysis was performed to explore gene expression profilings, while luciferase reporter assay to evaluate the transcriptive activity of Tcf/Lef. Results ZNF488 was over-expressed in NPC tissues compared with normal tissues, especially higher in 5-8F and S18, which are well-established high metastatic NPC clones. Functional studies indicate that over-expression of ZNF488 provokes invasion, whereas knock-down of ZNF488 alleviates invasive capability. Moreover, over-expression of ZNF488 promotes NPC tumor growth both in vitro and in vivo. Our data further show that over-expression of ZNF488 induces epithelial mesenchymal transition (EMT) by activating the WNT/β -catenin signaling pathway. Conclusion Our data strongly suggest that ZNF488 acts as an oncogene, promoting invasion and tumorigenesis by activating the Wnt/β -catenin pathway to induce EMT in NPC.
Zhong-Liu Zhou,Wen-Qing Yin,Xiao-Peng Zou,Dan-Ying Huang,Cui-Liu Zhou,Lian-Mei Li,Ke-Cheng Chen,Zi-Ying Guo,San-Qing Lin 한국응용생명화학회 2014 Applied Biological Chemistry (Appl Biol Chem) Vol.57 No.6
The extraction and solvent partition of the leaves ofEucalyptus citriodora, and repeated column chromatography for n-BuOH fraction yielded a new flavonoid glycoside, citrioside C (1),along with three known flavonoid glycosides (2-4). The latter wereidentified with kaempferol-3-O-β-D-glucopyranosyl (12)-α-L-rhamnoside(2), kaempferol-3-O-α-L-rhamnoside (3), and quercetin-3-O-α-Lrhamnoside(4). Their chemical structures were identified on thebasis of spectroscopic data analyses including NMR, MS, UV, andIR. All constitutents were isolated for the first time from the leavesof Eucalyptus citriodora. The potential antivirus activity of all theisolated compounds was evaluated. Compound 4 showed potentantiviral activity against respiratory syncytial virus with 50%inhibition concentration (IC50) value of 1.9 μg/mL and selectiveindex value of 9.8.
Kinetics of Sn(Oct)2-Catalyzed Ring Opening Polymerization of ε-Caprolactone
Dan Wu,Yin Lv,Rui Guo,Jiahui Li,Aerman Habadati,Bowen Lu,Heyun Wang,Zhong Wei 한국고분자학회 2017 Macromolecular Research Vol.25 No.11
To evaluate the effects of different alcohols (primary, secondary, and two different tertiary alcohols) as initiators on the structure of polycaprolactone (PCL) in ring-opening polymerization (ROP), four experiments were conducted in toluene with tin(II) 2-ethylhexanoate (Sn(Oct)2) as the catalyst. The kinetics of ε-caprolactone (ε-CL) ROP at different temperatures and monomer concentrations were studied with n-butanol as the initiator and Sn(Oct)2 as the catalyst. The kinetic plot of ln(M0/Mt) vs. time (t) seems a linear, which indicates that the propagation rate is in the first order with respect to monomer concentration. When the reaction temperature increased, the reaction rate and the final relative maximum monomer conversions also increased. The molecular weight of PCL initially increased and then decreased as monomer conversion increased. This behavior can be attributed to the high viscosity of the system, which affected monomer diffusion and polymer chain propagation. In addition, prolonging reaction time caused inter-/intramolecular transesterification. However, when monomer concentration decreased, the reaction rate decreased. The actual activation energy of Sn(Oct)2-catalyzed ROP of ε-CL in toluene was -75 kJ/mol.