Study on Corrosion Resistance of Magnesium Phosphate Cement-based Coating Modified by Metakaolin

Congcong Yu,Qing Wu,Hongli Ma,Ning Yang,Kojo Kumah Darkwah,Muhammad Akbar 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.1

Magnesium ammonium phosphate cement (MAPC) with a ceramic-like structure has good anti-corrosion properties. As an anti-corrosion coating, it can resist steel corrosion and reduces economic losses caused by steel corrosion. To further improve the anticorrosive properties of the coating, this study modified MAPC by partially replacing MgO with metakaolin (MK). Electrochemical tests analyzed the effect of MK on the anticorrosive properties of the coating. The results showed that the incorporation of MK significantly improved the anticorrosive properties of the coating, and the maximum improvement was obtained when the substitution amount was 15%. The compositions and microscopic morphology of the coatings were analyzed by X-ray diffraction (XRD), thermogravimetric analysis (TG-DTG), and scanning electron microscopy (SEM). According to the results, MK addition did not significantly alter the main composition of the coating, but the MK promoted the formation of MgNH4PO4·6H2O(MAP) to some extent. The microscopic morphology of the coating surface showed that the crystals were stacked together in flower-like layers before soaking, and the crystals grew more entirely after soaking. The internal microstructure of the coating is very dense, which helps to resist the erosion of corrosive media. In addition, the changes in coating pores before and after the incorporation of MK were tested by low-field nuclear magnetic resonance (LF-NMR). Based on the results, the doping of MK can optimize the pores of the coating and reduce its porosity. It is feasible to replace part of the MgO with MK to improve the corrosion resistance of magnesium phosphate cement-based coating, and the optimal dosage of MK is 15%. This research is helpful to improve the anti-corrosion performance of the coating and reduce corrosion costs.

백자 범당세 문집의 판본에 대한 고찰

우샹 ( Wu Xiang ),치우총총 ( Qiu Congcong ) 연민학회 2016 淵民學志 Vol.26 No.-

범백자의 문집은 그가 만년에 직접 편집을 한 것이나 오랫동안 출판되지 못하였다가, 절강 徐氏의 교정으로 정각본이 출판되었다. 20~30년 동안 사람들은 그 문집의 전모를 보지 못하였기에, 범당세의 저술을 논의함에 있어서 오류가 많았다. 문집이 절강 서씨에 의해 간행되기 전에 작성된 여러 편의 문집의 서발문을 살펴보니, 간행까지의 사정이 곡절이 많고 복잡하여 한 두 마디로 개괄할 수 없었다. 따라서 필자는 여러 편 자료를 고찰하여, 문집 간행의 자세한 상황을 정리하였고, 잘못된 오류에 대해 고증을 진행하였다. Fan Bozi`s anthology is written in his later years, but failed to publish. Until the Zhejiang Tsui better text appears, can not people see all his articles for twenty or thirty years. So, when people talk about his work, there will always be an error. By studying the preface of many anthologies, it was found that his collection of anthologies was complicated. Through a number of materials , the author sortes out his collection version of the situation, and make corrections to the error.

Geochemical identification of the source and environment of produced water from CBM wells and its productivity significance: examples from typical CBM wells in eastern Yunnan and western Guizhou

Zhaobiao Yang,Congcong Wu,Yong Qin,Geng Li,Zonghao Qin 한국지질과학협의회 2020 Geosciences Journal Vol.24 No.4

The geochemical information of produced water from coalbed methane (CBM) wells is abundant in geological significance. Based on the conventional ions, hydrogen and oxygen isotopes (δD and δ18O) and trace element tests of 27 produced water samples from CBM wells, the geochemical identification of the source and environment of produced water from CBM wells and its productivity significance have been analysed. The following conclusions have been drawn: CBM produced water can be divided into three categories, namely, polluted water from frac fluids, polluted surface water and formation water. The formation water has low Cl– concentration, low total dissolved solids (TDS) concentration, and light δD and δ18O. The water polluted by frac fluid has high Cl– and TDS concentrationt, and heavy δD and δ18O. The polluted surface water has high SO42– and light δD and δ18O. CBM groundwater environments can be divided into confined and unconfined systems. The confined system is characterized by low Na+/Cl– value, high (Cl– – Na+)/Mg2+ value, a general absence of SO42–, high Sr and Ba and low F. The unconfined system is characterized by high Na+/Cl– value, low (Cl– – Na+)/Mg2+ value, low SO4 2–, low Sr and Ba and high F. Constructing a cross plot with the new D drift index (d’) value and Cl– concentration can further identify four types of source-water environments: an unconfined formation water system, an unconfined surface water system, a confined system heavily polluted by frac fluids, and a confined system only slightly polluted by frac fluids. The unconfined system often produces more formation water and has high CBM production. The confined system often produces water more heavily polluted by frac fluids and is low in CBM production. The fitting formulas of hydrochemical productivity have been established for daily CBM and water production of CBM wells.

Research on facility layout optimization algorithm of deep-water semi-submersible drilling platform

Hongyan Wang,Wensheng Xiao,Lei Wu,Keke Wei,Congcong Xu,Chao Hou,Junguo Cui,Jie Li 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.2

We aimed to create a facility layout design of semi-submersible drilling platform (DSDP) with performance constraints. The Boltzmann survival mechanism of simulated annealing algorithm was introduced into the replacement strategy of genetic algorithm to form an improved genetic algorithm called genetic and simulated annealing algorithm (GASA). The new algorithm alleviates the “combination explosion” and premature convergence of the traditional genetic algorithm. The layout problem of DSDP is efficiently solved by using this new algorithm. When the number of layout objects increases, GASA’s performance is better than that of the genetic algorithm.

Analysis of multi-coalbed CBM development methods in western Guizhou, China

Zhaobiao Yang,Yong Qin,Tongsheng Yi,Jun Tang,Zhengguang Zhang,Congcong Wu 한국지질과학협의회 2019 Geosciences Journal Vol.23 No.2

After more than 20 years of development, the exploration and production of multi-bed coalbed methane in western Guizhou is now in a key growth phase. Based on geological characteristics of CBM and requirements of main development engineering in this area, we have looked into suitable fracturing and drainage modes for this area. This study shows that the Liupanshui coalfield has a high stress field, so staged fracturing with large discharge and high volume of fracturing fluid and sand and increase of the used quantity of high strength ceramic beads is effective for this kind of multi-bed coal reservoir. In contrast, Zhina coalfield has a relatively low stress field, and the Qianbei coalfield has transitional stress conditions. Separate layer fracturing by sleeve diverter in the Zhijin block ensures effective fracturing of multi-production layers. This method enhances fracturing efficiency and decreases fracturing cost and is therefore recommended for the whole area. Coiled tubing fracturing widely used in other countries is recommended for the Zhina and Qianbei coalfields. Commingled drainage and production is considered the best choice for the development of multi-bed CBM reservoirs. The basic geologic conditions for commingled drainage production of multiple layers are that the main productive layers can be ensured to produce gas preferentially and smoothly and the critical desorption pressure liquid level of other productive layers are above the roof depth of the main productive layers. On this basis, all the layers can be produced in an orderly manner by regulating the casing pressure and liquid level depth in different draining phases.

Resequencing 302 wild and cultivated accessions identifies genes related to domestication and improvement in soybean

Zhou, Zhengkui,Jiang, Yu,Wang, Zheng,Gou, Zhiheng,Lyu, Jun,Li, Weiyu,Yu, Yanjun,Shu, Liping,Zhao, Yingjun,Ma, Yanming,Fang, Chao,Shen, Yanting,Liu, Tengfei,Li, Congcong,Li, Qing,Wu, Mian,Wang, Min,Wu, Nature Publishing Group, a division of Macmillan P 2015 Nature biotechnology Vol.33 No.4

Understanding soybean (Glycine max) domestication and improvement at a genetic level is important to inform future efforts to further improve a crop that provides the world's main source of oilseed. We detect 230 selective sweeps and 162 selected copy number variants by analysis of 302 resequenced wild, landrace and improved soybean accessions at >11× depth. A genome-wide association study using these new sequences reveals associations between 10 selected regions and 9 domestication or improvement traits, and identifies 13 previously uncharacterized loci for agronomic traits including oil content, plant height and pubescence form. Combined with previous quantitative trait loci (QTL) information, we find that, of the 230 selected regions, 96 correlate with reported oil QTLs and 21 contain fatty acid biosynthesis genes. Moreover, we observe that some traits and loci are associated with geographical regions, which shows that soybean populations are structured geographically. This study provides resources for genomics-enabled improvements in soybean breeding.

Small molecule natural compound agonist of SIRT3 as a therapeutic target for the treatment of intervertebral disc degeneration

Jianle Wang,Majid Nisar,Chongan Huang,Xiangxiang Pan,Dongdong Lin,Gang Zheng,Haiming Jin,Deheng Chen,Naifeng Tian,Qianyu Huang,Yue Duan,Yingzhao Yan,Ke Wang,Congcong Wu,Jianing Hu,Xiaolei Zhang,Xiangy 생화학분자생물학회 2018 Experimental and molecular medicine Vol.50 No.-

Oxidative stress-induced mitochondrial dysfunction is implicated in the pathogenesis of intervertebral disc degeneration (IVDD). Sirtuin 3 (SIRT3), a sirtuin family protein located in mitochondria, is essential for mitochondrial homeostasis; however, the role of SIRT3 in the process of IVDD has remained elusive. Here, we explored the expression of SIRT3 in IVDD in vivo and in vitro; we also explored the role of SIRT3 in senescence, apoptosis, and mitochondrial homeostasis under oxidative stress. We subsequently activated SIRT3 using honokiol to evaluate its therapeutic potential for IVDD. We assessed SIRT3 expression in degenerative nucleus pulposus (NP) tissues and oxidative stressinduced nucleus pulposus cells (NPCs). SIRT3 was knocked down by lentivirus and activated by honokiol to determine its role in oxidative stress-induced NPCs. The mechanism by which honokiol affected SIRT3 regulation was investigated in vitro, and the therapeutic potential of honokiol was assessed in vitro and in vivo. We found that the expression of SIRT3 decreased with IVDD, and SIRT3 knockdown reduced the tolerance of NPCs to oxidative stress. Honokiol (10 μM) improved the viability of NPCs under oxidative stress and promoted their properties of anti-oxidation, mitochondrial dynamics and mitophagy in a SIRT3-dependent manner. Furthermore, honokiol activated SIRT3 through the AMPKPGC- 1α signaling pathway. Moreover, honokiol treatment ameliorated IVDD in rats. Our study indicated that SIRT3 is involved in IVDD and showed the potential of the SIRT3 agonist honokiol for the treatment of IVDD.