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Experimental study of welding effect on grade S690Q high strength steel butt joint
Cheng Chen,Sing-Ping Chiew,Mingshan Zhao,Chi King Lee,Tat Ching Fung 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.39 No.4
This study experimentally reveals the influence of welding on grade S690Q high strength steel (HSS) butt joints from both micro and macro levels. Total eight butt joints, taking plate thickness and welding heat input as principal factors, were welded by shielded metal arc welding. In micro level, the microstructure transformations of the coarse grain heat affected zone (CGHAZ), the fine grain heat affected zone (FGHAZ) and the tempering zone occurred during welding were observed under light optical microscopy, and the corresponding mechanical performance of those areas were explored by micro-hardness tests. In macro level, standard tensile tests were conducted to investigate the impacts of welding on tensile behaviour of S690Q HSS butt joints. The test results showed that the main microstructure of S690Q HSS before welding was tempered martensite. After welding, the original microstructure was transformed to granular bainite in the CGHAZ, and to ferrite and cementite in the FGHAZ. For the tempering zone, some temper martensite decomposed to ferrite. The performed micro-hardness tests revealed that an obvious “soft layer” occurred in HAZ, and the HAZ size increased as the heat input increased. However, under the same level of heat input, the HAZ size decreased as the plate thickness increased. Subsequent coupon tensile tests found that all joints eventually failed within the HAZ with reduced tensile strength when compared with the base material. Similar to the size of the HAZ, the reduction of tensile strength increased as the welding heat input increased but decreased as the thickness of the plate increased.
Jung, Sung Keun,Lee, Mee-Hyun,Lim, Do Young,Kim, Jong Eun,Singh, Puja,Lee, Sung-Young,Jeong, Chul-Ho,Lim, Tae-Gyu,Chen, Hanyong,Chi, Young-In,Kundu, Joydeb Kumar,Lee, Nam Hyouck,Lee, Charles C.,Cho, Y American Society for Biochemistry and Molecular Bi 2014 The Journal of biological chemistry Vol.289 No.52
<P>Non-small-cell lung cancer (NSCLC) is associated with diverse genetic alterations including mutation of epidermal growth factor receptor (EGFR). Isoliquiritigenin (ILQ), a chalcone derivative, possesses anticancer activities. In the present study, we investigated the effects of ILQ on the growth of tyrosine kinase inhibitor (TKI)-sensitive and -resistant NSCLC cells and elucidated its underlying mechanisms. Treatment with ILQ inhibited growth and induced apoptosis in both TKI-sensitive and -resistant NSCLC cells. ILQ-induced apoptosis was associated with the cleavage of caspase-3 and poly-(ADP-ribose)-polymerase, increased expression of Bim, and reduced expression of Bcl-2. <I>In vitro</I> kinase assay results revealed that ILQ inhibited the catalytic activity of both wild type and double mutant (L858R/T790M) EGFR. Treatment with ILQ inhibited the anchorage-independent growth of NIH3T3 cells stably transfected with either wild type or double-mutant EGFR with or without EGF stimulation. ILQ also reduced the phosphorylation of Akt and ERK1/2 in both TKI-sensitive and -resistant NSCLC cells, and attenuated the kinase activity of Akt1 and ERK2 <I>in vitro</I>. ILQ directly interacted with both wild type and double-mutant EGFR in an ATP-competitive manner. A docking model study showed that ILQ formed two hydrogen bonds (Glu-762 and Met-793) with wild type EGFR and three hydrogen bonds (Lys-745, Met-793, and Asp-855) with mutant EGFR. ILQ attenuated the xenograft tumor growth of H1975 cells, which was associated with decreased expression of Ki-67 and diminished phosphorylation of Akt and ERK1/2. Taken together, ILQ suppresses NSCLC cell growth by directly targeting wild type or mutant EGFR.</P>
Synthesis and Evaluation of Homoazasugars as Glycosidase Inhibitors
Wong, Chi-Huey,Louis, Provencher,John A. Porco, Jr.,Jung, Sang-Hun,Wang, Yi-Fong,Chen, Lihren,Wang, Ruo,Darryl H. Steensma 충남대학교 약학대학 의약품개발연구소 1995 藥學論文集 Vol.11 No.-
In an effort to develop transition-state mimetics of the glycosidase-catalyzed reaction, five- and six-membered azasugars and their homo-analogs were prepared and tested as inhibitors of glycosidases. Inhibition studies indicate that the fucosyl cationlike, five-membered imine 1 and its reduced form 2 are potent inhibitors of α-fucosidase from bovine kideney with respective K_i values of 160 nM and 2μM. The five-membered homoaminoazasugar 3 is also a potent inhibitor of the enzyme (K_i=1.9×10^-6M), while the glucose and mannose-like six-membered homoaminoazasugars 4 and 5 are less potent than the corresponding 1-deoxyazasugars as inhibitors of α-glucosidase and α-mannosidase, respectively. The primary amino group was placed in an attempt to introduce additional electrostatic interactions in the active site. The inhibitory activities are, however, in the high μM range. Synthesis of homoazasugars structurally related to a disaccharide and a nucleoside is also described.
Fabrication of semi-transparent super-hydrophobic surface based on silica hierarchical structures
Ping-Hei Chen,Chin-Chi Hsu,Pei-Shan Lee,Chao-Sung Lin 대한기계학회 2011 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.25 No.1
This study successfully develops a versatile method of producing superhydrophobic surfaces with micro/nano-silica hierarchical structures on glass surfaces. Optically transparent super hydrophobic silica thin films were prepared by spin-coating silica particles suspended in a precursor solution of silane, ethanol, and H_2O with molar ratio of 1:4:4. The resulting super hydrophobic films were characterized by scanning electron microscopy (SEM), optical transmission, and contact angle measurements. The glass substrates in this study were modified with different particles: micro-silica particles, nano-silica particles, and hierarchical structures. This study includes SEM micrographs of the modified glass surfaces with hierarchical structures at different magnifications.
Authorized Tracking and Tracing for RFID
Ming-Yang Chen,Ching-Nung Yang,Chi-Sung Laih 보안공학연구지원센터 2007 International Journal of Security and Its Applicat Vol.1 No.1
Radio Frequency Identification (RFID) systems have become popular for identifying not only objects but also persons. For example, in supply chain applications, the company can constantly track the movements of goods. Also, for Body Area Network or Personal Area Work, the tag is usually used for identifying a person. However, the movements and current locations of goods and a person’s activity profiles are the sensitive information and should be kept secret. This paper develops the interaction protocols between readers and tags to address this privacy issue of protecting tagged objects from tracking and tracing by unauthorized readers.