The mechanism of inhibitive effect on hydrogen permeation of X70 steel by lanthanum microalloying: Enhanced kinetics of desorption

Zhengyi Xu,Pengyuan Zhang,Bo Zhang,Bing Lei,Zhiyuan Feng,Junyi Wang,Yawei Shao,Guozhe Meng,Yanqiu Wang,Fuhui Wang 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.122 No.-

In this work, electrochemical hydrogen permeation tests were carried out to obtain the steady-statehydrogen permeation current of X70 pipeline steel in acid environment and alkaline electrolyte withapplied cathodic overpotentials simulating the service conditions of pipelines. It is shown that Lamicroalloyingcan efficiently reduce the steady-state hydrogen permeation current density while maintainingthe same mechanical performance. The experimental permeation data were fitted with Iyer-Pickering-Zamanzadeh (IPZ) and surface effect model to analyze the inhibitive mechanism on hydrogenpermeation, and the results depicted that La element on the material surface greatly facilitates the desorptionprocess of hydrogen atoms. In addition, the calculated hydrogen diffusion coefficient was foundsmaller after La microalloyed, which can be ascribed to the larger hydrogen trap density. It is suggestedthat La-microalloying can mitigate hydrogen damage of X70 pipeline steel in both acidic environment orunder cathodic protection.

Study of co-excited green emission of Tb3+, Ce3+ and Gd3+ in yttrium aluminum garnet

Fei Huang,Limin Dong,Hao Wang,Weimin Wang,Yucheng Wang,Zhengyi Fu 한양대학교 세라믹연구소 2009 Journal of Ceramic Processing Research Vol.10 No.6

YAG : Tb3+, Ce3+, Gd3+ nano-phosphors derived from a sol-gel chemistry have been successfully synthesized and characterized by TG/DTA, XRD, SEM, and spectrometer. The results show that the phosphors have a uniform particle size distribution ranging 30-50 nm. The value of the lattice constant increased with an increase of the Gd3+ content. Tb3+ →Ce3+, Ce3+ →Tb3+ and Gd3+ →Ce3+ energy transfer existed in the co-excited system. The luminescence intensity was controlled by the concentration and ratio of the co-dopants. A small quantity of Gd3+ and Ce3+ evidently increased the green emission (5D4→7F5) of Tb3+. YAG : Tb3+, Ce3+, Gd3+ nano-phosphors derived from a sol-gel chemistry have been successfully synthesized and characterized by TG/DTA, XRD, SEM, and spectrometer. The results show that the phosphors have a uniform particle size distribution ranging 30-50 nm. The value of the lattice constant increased with an increase of the Gd3+ content. Tb3+ →Ce3+, Ce3+ →Tb3+ and Gd3+ →Ce3+ energy transfer existed in the co-excited system. The luminescence intensity was controlled by the concentration and ratio of the co-dopants. A small quantity of Gd3+ and Ce3+ evidently increased the green emission (5D4→7F5) of Tb3+.

A Multiple Moving Object Segmentation Algorithm Based on Background Modeling and Adaptive Clustering

Zhengyi Hu,Qingchang Tan,Kun Zhang,Xin Wang 보안공학연구지원센터 2015 International Journal of Signal Processing, Image Vol.8 No.12

A multiple moving object segmentation algorithm based on Background Modeling and Adaptive Clustering (named as BMAC) algorithm is proposed in this paper. For moving object segmentation, the algorithm uses Chebyshev inequality and the kernel density estimation method to do background modeling firstly. Then in order to classify image pixels as background points, foreground points and suspicious points, an adaptive threshold algorithm is proposed accordingly. After using background modeling, adaptive clustering is used for multi-object segmentation. It defines pixel space connectivity rate and designs a perpendicular split method, initial cluster adaptive splitting and merging self-organizing the iterative clustering segmentation algorithm, without pre-set number of clustering, completes multi-object segmentation for the foreground image. The segmentation results are consistent with the human visual judgment, the use of space connectivity information improve the accuracy of clustering segmentation, comparison and analysis the experimental results show that the proposed algorithm is feasible, rapid and effective.

AlN matrix composites fabricated by the spark plasma sintering –reactive synthesis method

Tiekun Jia,Weimin Wang,Zhengyi Fu,Hao Wang 한양대학교 세라믹연구소 2009 Journal of Ceramic Processing Research Vol.10 No.6

A mixture of Al and BN powders was adopted to synthesize AlN matrix composites using the spark plasma sintering-reactive (SPS) synthesis method. The crystalline phases of sintered samples were characterized by X-ray diffraction (XRD). Scanning electron microscope (SEM) and transmission electron microscope (TEM) images of the microstructure revealed that the BN phase was homogeneously distributed in the matrix of synthesized AlN. The effect of sintering temperature on the microstructure and properties of sintered samples was investigated. The results showed that densification of sintered samples was improved and the thermal conductivity exhibited a significant increase with an increase of the sintering temperature. A mixture of Al and BN powders was adopted to synthesize AlN matrix composites using the spark plasma sintering-reactive (SPS) synthesis method. The crystalline phases of sintered samples were characterized by X-ray diffraction (XRD). Scanning electron microscope (SEM) and transmission electron microscope (TEM) images of the microstructure revealed that the BN phase was homogeneously distributed in the matrix of synthesized AlN. The effect of sintering temperature on the microstructure and properties of sintered samples was investigated. The results showed that densification of sintered samples was improved and the thermal conductivity exhibited a significant increase with an increase of the sintering temperature.

Study on Bond-Slip Behaviors of Self-Stressing Steel Slag Concrete-Filled Steel Tube

Feng Yu,Taiyao Chen,Kang Niu,Shilong Wang,Zhengyi Kong,Yuan Fang 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.11

The bond-slip behaviors of self-stressing steel slag concrete filled steel tubes (SSSSCFST) are investigated by carrying out the push-out tests. The influence of thickness to diameter ratio, confining parameter and expansion ratio of steel slag concrete (SSC) on bond-slip performance are analyzed. Investigations of the failure modes of each specimen indicate that the shear failure of the bond interface dominates the failure of the specimen. Further, three stages of the load-slip relationship curve of bond slip was observed, i.e., the loading stage, descending section and constant load section. In the loading section, with the increase in thickness to diameter ratio or confining parameter, the interface bonding force of specimen improves firstly and then decreases. Besides, the interfacial bond strength increases with enhancement of the expansion ratio. In the descending section, the interfacial bonding force raises with improvement of diameter-thickness ratio, while decreases as the confining parameter and expansion ratio increase. Moreover, the influence of considered parameters on the ultimate interface bond load is analyzed. Finally, a theoretical model for the bond-slip behaviors of SSSSCFST is proposed by accounting for the non-uniform distribution of interface bond strength. It indicates that the theoretical model can well capture the main features that are exhibited during the whole process of push-out test.

The Application of Built-in Beam Element Method in the Aqueduct Pile Foundation Analysis

Shiyang Pan,Tongchun Li,Xiao Qing Liu,Jian-qun Zhu,Zhen Cui,Zhengyi Wang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.7

The solution using built-in beam element method to increase the calculation efficiency of aqueduct pile foundations is studied in this work. The formulations of built-in beam element method based on the normal generalized displacement method of beam element are introduced in this work. Then, the validity of the built-in beam element method is checked by a static problem of a simplified aqueduct model. Furthermore, the solution to increase calculation efficiency by built-in beam element method for aqueduct pile foundations is introduced by studying the features of built-in beam element method and normal generalized displacement method of beam element in models with different grid density and foundation stiffness. Finally, a static problem of an arch aqueduct is solved using the summed solution. The results show that it is feasible to improve efficiency with sufficient accuracy by reasonably selecting the built-in beam element method and normal generalized displacement method in the analysis of aqueduct pile foundation.

Gene Expression Profiles of HeLa Cells Impacted by Hepatitis C Virus Non-structural Protein NS4B

Zheng, Yi,Ye, Lin-Bai,Liu, Jing,Jing, Wei,Timani, Khalid A.,Yang, Xiao-Jun,Yang, Fan,Wang, Wei,Gao, Bo,Wu, Zhen-Hui Korean Society for Biochemistry and Molecular Biol 2005 Journal of biochemistry and molecular biology Vol.38 No.2

By a cDNA array representing 2308 signal transduction related genes, we studied the expression profiles of HeLa cells stably transfected by Hepatitis C virus nonstructural protein 4B (HCV-NS4B). The alterations of the expression of four genes were confirmed by real-time quantitative RT-PCR; and the aldo-keto reductase family 1, member C1 (AKR1C1) enzyme activity was detected in HCV-NS4B transiently transfected HeLa cells and Huh-7, a human hepatoma cell line. Of the 2,308 genes we examined, 34 were up-regulated and 56 were down-regulated. These 90 genes involved oncogenes, tumor suppressors, cell receptors, complements, adhesions, transcription and translation, cytoskeletion and cellular stress. The expression profiling suggested that multiple regulatory pathways were affected by HCV-NS4B directly or indirectly. And since these genes are related to carcinogenesis, host defense system and cell homeostatic mechanism, we can conclude that HCV-NS4B could play some important roles in the pathogenesis mechanism of HCV.

Centromere protein N promotes lung adenocarcinoma progression by activating PI3K/AKT signaling pathway

Zheng Yi,You Hui,Duan Jingzhu,Chen Biyu,Wu Chenlin,Chen Peipei,Wang Meifang 한국유전학회 2022 Genes & Genomics Vol.44 No.9

Background: As an important member of centromere family, centromere associated protein N (CENPN) was abnormally expressed in varied malignant tumors. Objective: This paper aimed to analyze the expression and related mechanism of CENPN in lung adenocarcinoma (LUAD). Methods: The expression of CENPN in LUAD was analyzed by Gene Expression Profiling Interactive Analysis (GEPIA) database. The mRNA expression, protein expression, cell viability, cell invasion, cell apoptosis, cell stem like characteristics were detected by RT-PCR, western blot, CCK8 assay, transwell assay, flow cytometry and spheroidization assay, respectively. Finally, the pathological changes of xenograft were estimated by H&E staining, and the expression of proteins was detected by immunohistochemistry. Results: GEPIA analysis showed that the CENPN expression in LUAD was significantly higher than that in normal lung tissue, which was negatively correlated with the prognosis. These results were consistent with our clinical data. Besides, CENPN was highly expressed in LUAD cell lines. In addition, the upregulation of CENPN amplified the cell viability, stemness and invasive ability in PC9 cells. However, the knockdown of CENPN inhibited the cell activity, stemness, invasive ability with increased cell apoptosis in A549. Furthermore, CENPN could positively regulate the phosphorylation of PI3K and AKT. The PI3K inhibitor, 740Y-P, could reverse the effect of CENPN silencing on the expression of Ki-67, cleaved caspase 3, OCT4, and snail 1. Finally, the downregulation of CENPN restrained the growth of xenograft and inactivated the PI3K/AKT pathway. Conclusion: CENPN was abnormally overexpressed in LUAD, and promoted tumor progression of LUAD by affecting PI3K/AKT pathway.