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516 results on '"Liu, Yongchang"'

2. Cloning and expression analysis of the SAURX gene in Gossypium hirsutum

Author

LIU Yongchang, MA Xiaomei, WU Zhongxin, SUN Yujin, and CHEN Na

Subjects
gossypium hirsutum, auxin, saur, cell elongation, expression analysis, Biology (General), QH301-705.5, Botany, QK1-989
Abstract

[ Objective ] Small auxin up RNAs ( SAURs ), which belong to a kind of auxin early response gene , play an key role in plant cell elongation. This study aims to clone fiber development-related SAUR genes , study their expression pattern and biological function. There is of great significance for exploring the mechanism of fiber development. [ Methods ] A gene encoding SAUR protein was cloned from Gossypi- um hirsutum , and was named GhSAURX . Expression pattern , subcellular localization , phenotypic identi- fication of the transgenic Arabidopsis , and expression of auxin-related genes were performed. [ Results ] Phylogenetic analysis revealed that GhSAURX had close relationship with SAUR76 , SAUR77 , and SAUR78 in Arabidopsis , and was belonged to the SAUR76 subfamily. qRT-PCR showed that the highest expression level of GhSAURX was observed in fiber of 15 , 18 and 21 DPA , when fiber was elongating fast. Meanwhile , GhSAURX showed much higher expression level in varieties with long fiber than that in varieties with short fiber. Analysis of subcellular localization indicated that GhSAURX was distributed in cytoplasm and nucleus. Overexpression of GhSAURX promoted the elongation of the primary roots and hypocotyls under dark condition in Arabidopsis , and enhanced the expression of auxin-related genes , such as YUCCA6 , ARF7 , and PIN4 . [ Conclusion ] Our results indicated that GhSAURX functions in the cell elongation mediated by auxin.

Published
2024
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38. Improving the Oxidation Resistance of G115 Martensitic Heat-Resistant Steel by Surface Treatment with Shot Peening.

Author

Chen, Pengwen, Zhang, Jingwen, Yu, Liming, Du, Tianyu, Li, Huijun, Liu, Chenxi, Liu, Yongchang, Liu, Yuehua, and Du, Baoxin

Subjects
SURFACE preparation, SHOT peening, STEEL, OXIDATION kinetics, WEIGHT gain, CRYSTAL grain boundaries
Abstract

G115 steel is a novel martensitic heat-resistant steel, primarily utilized in the main steam pipelines and collectors of ultra-supercritical thermal power units. However, the oxidation resistance of martensitic steels in the high-temperature steam environment is usually suboptimal, significantly affecting the efficiency of power plants. In this paper, shot peening (SP) is employed as a surface treatment method for G115 steel, and the oxidation kinetics, oxide layer thickness, and microstructure of shot-peened G115 samples are compared with those of G115 steel. The results indicate that in the 650 °C steam environment, the oxidation kinetics of the shot-peened samples follow the parabolic law and that the oxidation weight gain is significantly smaller than that of the non-shot-peened samples. The higher the SP intensity, the smaller the oxidation weight gain and the better the oxidation resistance. This can be attributed to the fragmentation of the grains in the surface layer caused by external stress during SP, which creates a multitude of grain boundaries that can provide rapid diffusion pathways for corrosion-resistant Cr atoms, resulting in the accelerated outward diffusion of Cr atoms from the substrate. Simultaneously, a continuous and dense FeCr2O4 protective layer is produced at the interface between the SP layer and the substrate, obstructing the inward diffusion of oxygen and enhancing the oxidation resistance of G115 steel. [ABSTRACT FROM AUTHOR]

Published
2024
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44. Mg coating induced superconductivity in the FeSe ultrathin film

Author

Qiu, Wenbin, Ma, Zongqing, Liu, Yongchang, Wang, Xiaolin, and Dou, Shi Xue

Subjects
Condensed Matter - Superconductivity
Abstract

The transition from insulator to superconductor was achieved in the non-superconducting FeSe ultrathin film via simple Mg coating technique in present work. It was found that in non-superconducting FeSe ultrathin film without Mg coating, insulating \b{eta}-Fe1-xSe phase with iron-vacancy disorders is the main phase and more likely to be the parent phase of FeSe superconducting system. Proper Mg coating on the surface of FeSe films can lead to Mg entering FeSe crystal lattice to fill up these Fe vacancies rather than replace Fe. Simultaneously, additional electron doping is introduced and the electron carrier concentration in this parent phase can be tuned, which is responsible for the SIT and evolution of superconductivity in this system. However, abnormal decrease of electron concentration was found in FeSe film with excessive Mg coating, which brings about the severe degradation in superconducting performance., Comment: arXiv admin note: substantial text overlap with arXiv:1512.00352

Published
2015

45. Transition from insulator to superconductor and significant enhancement of superconductivity in FeSe films via tuning Fe-vacancy disorders

Author

Qiu, Wenbin, Ma, Zongqing, Liu, Yongchang, Wang, Xiaolin, and Dou, Shi Xue

Subjects
Condensed Matter - Superconductivity
Abstract

In contrast to its bulk crystals, the FeSe film or layer exhibits better superconductivity performance, which attract much interest in its fundamental research as well as potential application. In present work, transition from insulator to superconductor and significant enhancement of superconductivity were achieved in the high quality (00l) oriented FeSe films via controlling the thickness as well as the Fe/Se ratio. The highest Tc up to 15.2 K (almost 2 times higher than those of bulk crystals) and Hc2 up to 35.5 T are obtained in our atmosphere-stable FeSe thin film with practical thickness (240 nm), implying their great potential application in the electronic devices at high magnetic fields. More importantly, it was found that the Fe-vacancy disorder in FeSe films is the intrinsic factor determining the evolution of the superconductivity, rather than thickness effect. In our non-superconducting FeSe film with Fe/Se ratio of 1.00:1.09, insulating \b{eta}-Fe1-xSe phase with iron-vacancy disorders is the main phase and more likely to be the parent phase of FeSe superconducting system. Tuning the Fe-vacancy disorders via changing the Fe/Se ratio can dramatically vary the concentration of charge carrier and introduce proper electron doping, which finally leads to the transition from insulator to superconductor and further enhancement in the superconductivity. Intriguingly, our results also indicate that when the Fe/Se ratio of film is beyond a critical value, superconducting FeSe films will become instable, and phase separation occurs with new non-superconducting phase precipitating in the superconducting matrix, causing the degradation in the superconductivity. The results in present work help us to well understand the intrinsic mechanism of superconductivity among Fe-Se superconducting system and provide a new strategy to further pursue higher Tc in these materials., Comment: This paper has been withdrawn by the author for the reason that some updated results was found

Published
2015

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