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Qing-dong Liu,Wen-qing Liu,Shi-jin Zhao 대한금속·재료학회 2013 METALS AND MATERIALS International Vol.19 No.4
3D atom probe (3DAP) combined with TEM is applied to characterize the nanostructure and composition of coarsening carbides that precipitate in a Nb-V micro-alloyed steel tempered at 650 °C for 4 h. The results indicate that high temperature tempering of the as-quenched lath-like martensitic structures leads to the coarsening of alloyed carbide in the recovered ferritic matrix. TEM characterization and EDS analysis show that the alloy carbides are typically spherical or ellipsoidal and are enriched with V, Nb and Mo. Crystallographic lattice overlap and distortion create a distinct optical Moiré pattern at the carbide/matrix boundary, as observed by HRTEM. 3DAP gives the compositional distribution at atomic scale in the coarsening carbide and the surrounding matrix. Non-carbide-forming elements such as Si and Al are depleted in the carbide and are enriched at the carbide/matrix heterophase interface. Carbide-forming elements such as Mn, V, Mo and Nb distribute heterogeneously in the whole carbide, leading to the formation of a Mn-, V- and Mo-enriched core and Mo-enriched external shell.
Qing Jin,Zehua Bu,Dong-dong Pan,Xiaojie Gao,Pengshuai Yang,Haiyan Li,Zhaofeng Li,Zhenhao Xu 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.2
To address the problem on grouting control of water inflow disaster in coastal area, a caisson-type grouting experimental system of a single fracture in flowing water under tidal action was developed independently. Through the tide simulation system, the tidal action of different intensity and frequency was effectively described. Tide simulation system, fracture system, grouting system, water supply system and information monitoring system were combined to realize the visualization of the whole grouting process under tidal action. Furthermore, the grouting experiments of a plate fracture under different tidal action were developed and the blocking mechanism under tidal action was revealed. The conclusions were as follow: 1) Under constant water head, the slurry had three typical diffusion patterns, which were circular distribution, double U-shaped distribution and elliptical distribution respectively. 2) Under tidal action, the pressure showed a periodic fluctuation growth, and the growth rate slowed down with the increase of fracture aperture. 3) Strong tidal action would promote the diffusion of and increased the outflow amount of slurry, which was not conducive to grouting. Based on the water inflow treatment project of limestone mine in Guangxi, Through the field grouting tests, the 2# water inflow point was blocked. The research results have a certain reference value for the technology optimization of grouting engineering in coastal areas.
The Three-wavelength PR<SUP>3+</SUP>:YLF Laser at 604 nm 607 nm and 640 nm with Fabry-Perot Etalon
Long Jin,Yu-Shi Jin,Yuan Dong,Qing-Song Li,Yong-Ji Yu,Shu-Tao Li,Guang-Yong Jin 한국광학회 2018 Current Optics and Photonics Vol.2 No.5
A three-wavelength Pr<SUP>3+</SUP>:YLF laser at 604 nm, 607 nm and 640 nm simultaneously output by Fabry-Perot (F-P) etalon has been obtained. A 444 nm blue laser diode is used for pumping the Pr<SUP>3+</SUP>:YLF crystal, and a 0.1 mm F-P etalon is inserted in the resonator to select wavelength. The theoretical model of three-wavelength Pr<SUP>3+</SUP>:YLF laser is established, by adjusting the tilt angle of the etalon, the transmittances of the different wavelengths can be controlled, and the threshold values can be made to equalize by controlling the loss among different wavelengths. In the experiment, when the tilt angle of etalon is 9° and the optimized length of resonator is 48 mm, the total output power of 25 mW at the three-wavelength is achieved at incident pump power of 7.5 W.
Han Ying-Hao,Mao Ying-Ying,Yu Nan-Nan,Jin Mei-Hua,Jin Ying-Hua,Wang Ai-Guo,Zhang Yong-Qing,Shen Gui-Nan,Cui Yu-Dong,Yu Li-Yun,Lee Dong-Seok,Jo Yu-Jin,Sun Hu-Nan,Kwon Jeongwoo,권태호 한국응용생명화학회 2020 Applied Biological Chemistry (Appl Biol Chem) Vol.63 No.3
In this study, we used RNA sequencing (RNA-seq) to analyze and compare bulk cell samples from wild-type (WT) dermal mesenchymal stem cells (DMSCs) (n = 3) and Prx II knockout DMSCs (n = 3). The purpose of the study was to elucidate the role of Prx II on allogeneic immune rejection of transplanted DMSCs. The results revealed differential expression of 472 genes (176 up-regulated and 296 down-regulated; p ≤ 0.05) between the PrxII+/+ (WT) and PrxII−/− sample groups. When highly regulated genes were categorized according to the Gene Ontology (GO) molecular function classification and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, the PrxII−/− samples showed a robust downward trend in allograft rejection. The study identified 43 all immunologically rejected differentially expressed genes, of which 41 showed lower expression in the PrxII−/− vs. PrxII+/+ (WT) samples. These findings suggest that Prx II gene knockout may down-regulate the allograft rejection that occurs during DMSCs transplantation and improve the survival rate of DMSCs in the host. This study provides a new perspective on the clinical treatment of stem cell transplantation.
Two New Bibenzyl Glucosides from Dendrobium chrysotoxum
Dong, Fa-Wu,Luo, Huai-Rong,Wan, Qin-Li,Xu, Feng-Qing,Fan, Wei-Wei,Wang, Kai-Jin,Li, Ning,Hu, Jiang-Miao Korean Chemical Society 2012 Bulletin of the Korean Chemical Society Vol.33 No.7
Two new bibenzyl glucosides, 3,3',4',5-tetramethoxybibenzyl-4-O-${\beta}$-D-glucopyranoside (1) and 3,4,4',5-tetramethoxybibenzyl-3'-O-${\beta}$-D-glucopyranoside (2), together with five known ones, chrysotobibenzyl (3), erianin (4), chrysotoxine (5), gigantol (6) and tristin (7) were isolated from the stems of Dendrobium chrysotoxum. The structures of those compounds were elucidated by extensive spectroscopic analysis. Moreover, compounds 1-7 were assessed for inhibitory activity of two enzymes-AChE (acetylcholine esterase) and BChE (butyrylcholine esterase).
Jin-Dong Wang,Qing-Jie Wang,Hai-Tao Li 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.4
To achieve the quick and accurate calibration of the geometric errors of NC machine tool, a new method with laser tracker on the basis of space vector’s direction measurement principle is proposed in the paper. A series of measuring points are mounted on the moving part of the machine tool, and then adjacent measuring points are connected to form a space vector respectively. Due to the motion error of the machine tool, the direction of the vectors composed will be changed. Meanwhile, the deviation of vector’s direction only relates to angular displacement error rather than linear displacement error. Based on the characteristic, the change of vectors’ direction is measured by laser tracker based on the multi-station and time-sharing measurement during the motion of machine tool, and then the angular displacement errors and linear displacement errors of each axis can be accurately identified successively, which reduces the complexity of error identification. By establishing the mathematical model of geometric error measurement of machine tool based on the principle of space vector’s direction measurement, the base station calibration algorithm by measuring the motion of the designed precise turntable, the measuring point determination algorithm and geometric error separation algorithm are derived respectively, and the accuracy of these algorithms are verified by simulations. In addition, the results of the experiments show the feasibility of the proposed method.