Effects of Si on the Microstructure and Work Hardening Behavior of Fe‒17Mn‒1.1C‒xSi High Manganese Steels

Renlong Xiong,Yi Liu,Haitao Si,Huabei Peng,Shanling Wang,Binhan Sun,Hanxin Chen,Hyoung Seop Kim,Yuhua Wen 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.10

In order to improve the work hardening capacity under low stresses and the yield strength of conventional Hadfield steels, theeffects of Si on the microstructure and work hardening behavior of the Fe‒17Mn‒1.1C‒xSi steels under both quasi-statictensile and low load impact are investigated. It is shown that the increase of the Si contents remarkably improves the yieldstrength by 36 MPa per 1 wt% Si in the investigated steel system without significant sacrifice of ductility. The decreasingeffect of Si on the stacking fault energy is strongly affected by carbon, although the variation of carbon content was small. This led to the unexpected similar stacking fault energy between 1Si and 2Si steel. With the increase of the Si contents forthe steels, the critical strain for the onset of mechanical twinning was lowered, which was controlled by the cooperationbetween the stacking fault energy and solid solution strengthening of Si. This resulted in the earlier initiation of mechanicaltwins and an increase in the twin volume fraction. Therefore, the work hardening capacities under both quasi-static tensileand low load impact tests were enhanced. It was also found that the impact deformation decreased as more mechanical twinsabsorbed the impact energy.

비부비동 반정성 유두종의 전산화 단층촬영상과 자기공명영상의 분석

배창훈,서영중,이석춘,천승민,백운희,정은채,송시연,김용대 영남대학교 의과대학 2005 Yeungnam University Journal of Medicine Vol.22 No.2

Background: Computed tomography (CT) is commonly used to evaluate the degree of sinus involvement in case of inverted papilloma (IP). However, CT cannot differentiate tumor from adjacent inflammatory mucosa or retained secretions. By contrast, magnetic resonance imaging (MRI) has been reported to be useful in distinguishing IP from paranasal sinusitis. This study investigated whether preoperative assessment with MRI and CT accurately predict the extent of IP. Materials and methods: CT and MRI were retrospectively reviewed in 9 case of IP. Patients were categorized into staged based on CT and MRI findings according to the staging system proposed by Krouse. The involvement of IP in each sinus was also assessed. Results: Differentiation of IP from inflammatory disease may be more successful in routine case where the inflammatory mucosa has low signal intensity on T1-weighted images and very high signal intensity on T2-weighted images. CT imaging could not differentiate tumor from adjacent inflammatory mucosa or retained secretions. Conclusion: Preoperative MRI of IP can predict the location and extent of the tumor involvement in the paranasal sinuses and sometimes predicts malignant changes.

기업의 사회적 책임이(CSR) 브랜드 충성도에 미치는 영향 – 브랜드 신뢰와 e-WOM의 매개효과를 중심으로

진사사(Si-Si Chen),이염남(Yan-Nan Li) 한국콘텐츠학회 2021 한국콘텐츠학회논문지 Vol.21 No.11

브랜드 경쟁 시대에 기업은 소비자의 브랜드 신뢰도 및 충성도를 높이기 위해 많은 노력을 하고 있다. 기업의 사회적 책임이 기업의 브랜드 신뢰도 및 충성도를 높이는데 큰 역할을 하고 있다. 한편, 현재의 Covid-19 유행은 기업의 디지털 전환 속도를 가속화 했으며 소비자가 기업의 온라인 평가에 더 많은 관심을 기울이게 만들었다. 본 연구는 중국 소비자 시장을 기반으로 기업의 사회적 책임, 인터넷 입소문(e-WOM), 브랜드 신뢰를 통해 브랜드 충성도에 어떠한 영향을 미치는지에 대해 연구하였다. 이러한 연구목적을 확인하기 위해 본 논문에서는 중국과 한국에 있는 중국인 소비자를 대상으로 설문 조사를 실시하였다. 총 469개의 유효 설문이 사용되었고 수집된 데이터는 SPSS21.0를 활용해 실증 분석하였다. 연구 결과는 다음과 같이 요약된다. (1) 기업의 사회적 책임은 브랜드 신뢰에 긍정적인 영향을 미친다. (2) 기업의 사회적 책임은 브랜드 충성도에 긍정적인 영향을 미친다. (3) 브랜드 신뢰는 브랜드 충성도에 긍정적인 영향을 미친다. (4) 브랜드 신뢰와 인터넷 입소문은 기업의 사회적 책임과 브랜드 충성도의 사이에 긍정적인 매개효과가 나타낸다. In the era of brand economy, companies fulfill their social responsibilities to enhance consumers brand trust, thereby enhancing brand loyalty. On the other hand, the current Covid-19 epidemic has accelerated the pace of digital transformation of enterprises and has also made consumers pay more attention to the online reputation of enterprises. Based on the Chinese consumer market, this paper studies the corporate social responsibility, Internet word-of-mouth, brand trust, and brand loyalty of electronic product companies. To verify the impact of corporate social responsibility on brand loyalty through Internet word-of-mouth and brand trust, this paper issued a questionnaire survey to Chinese consumers. A total of 469 questionnaires were used for empirical analysis, and SPSS21.0 was used to analyze the collected data. The results are summarized as follows: (1) CSR has a positive impact on brand trust. (2) CSR has a positive impact on brand loyalty. (3) Brand trust has a positive impact on brand loyalty. (4) Brand trust and e-WOM play an intermediary role in CSR and brand loyalty.

Solid Texture Synthesis and Mapping of Liver for Virtual Surgery

Chen Si-Xi,Li Jian-Wei,Chen Guo-Dong 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.12

In order to see clearly the details inside the liver and enhance the users’ visual presence in the virtual surgery simulation system, the principles and methods of solid texture are used to render the photorealistic liver. Firstly, the sample sets are processed and multiple samples are used to synthesize the liver solid texture. Secondly, to improving the mapping efficiency of graphics hardware, the texture atlas is used to map the solid texture. In order to improve the fill rate of texture atlas, the height descending triangle bounding box method is used. The experimental result shows that the internal texture can be observed clearly. The study is of great significance to the photorealistic rendering of virtual liver surgery system, and provides a guideline for the solid texture synthesis and mapping of other human organs.

Bayesian change point analysis for extreme daily precipitation

Chen, Si,Li, Yaxing,Kim, Jinheum,Kim, Seong W. John Wiley Sons, Ltd 2017 International journal of climatology Vol.37 No.7

<P><B>ABSTRACT</B></P><P>Change point (CP) analysis of extreme precipitation plays a key role to incorporate non‐stationarity in flood predictions under climate change. This article provides a Bayesian method to detect the CP frequently appearing in extreme precipitation data. Unlike most published work based on a normal distribution, we allow for the model to follow a generalized Pareto distribution to fit extreme precipitation over a high threshold with a CP, which can effectively utilize tail behaviour of the distribution. The Bayesian CP detection is investigated on four models: a no change model, a shape change model, a scale change model, and both a shape and scale change model. Model selection is performed using the Bayes factor and model posterior probability; the posterior means of the unknown CP and the model parameters before and after the CP can be obtained based on the selected CP model. Simulation studies and a real data example are provided to demonstrate the proposed methodologies. Finally, model uncertainty issues in the frequency analysis are extensively discussed. It is found that considering the abrupt and sustained CP in extreme precipitation is important when performing hydraulic or hydrologic design.</P>

OsSPL13 controls grain size in cultivated rice

Si, Lizhen,Chen, Jiaying,Huang, Xuehui,Gong, Hao,Luo, Jianghong,Hou, Qingqing,Zhou, Taoying,Lu, Tingting,Zhu, Jingjie,Shangguan, Yingying,Chen, Erwang,Gong, Chengxiang,Zhao, Qiang,Jing, Yufeng,Zhao, Y Nature Publishing Group, a division of Macmillan P 2016 Nature genetics Vol.48 No.4

<P>Although genetic diversity has a cardinal role in domestication, abundant natural allelic variations across the rice genome that cause agronomically important differences between diverse varieties have not been fully explored. Here we implement an approach integrating genome-wide association testing with functional analysis on grain size in a diverse rice population. We report that a major quantitative trait locus, GLW7, encoding the plant-specific transcription factor OsSPL13, positively regulates cell size in the grain hull, resulting in enhanced rice grain length and yield. We determine that a tandem-repeat sequence in the 5'UTR of OsSPL13 alters its expression by affecting transcription and translation and that high expression of OsSPL13 is associated with large grains in tropical japonica rice. Further analysis indicates that the large-grain allele of GLW7 in tropical japonica rice was introgressed from indica varieties under artificial selection. Our study demonstrates that new genes can be effectively identified on the basis of genome-wide association data.</P>

Experimental behavior of circular flyash-concrete-filled steel tubular stub columns

Si-Ping Li,Yang Zhang,Guang-Yuan Fu,Chen-Jiang Yu,Bing Chen,She-Xu Zhao 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.22 No.4

The paper presents an experimental study of the structural behavior of circular flyash-concrete-filled steel tubular stub columns under axial compressive loads. In this study, 90% and 100% by weight of the cement in the concrete core was replaced with flyash. Twenty-seven specimens were tested to study the influence of flyash content, wall thickness of the steel tube, and curing age on the ultimate capacity and confinement effect. The experimental results were compared with the design values calculated using AISC-LRFD (1999), ACI (1999), AIJ (1997) and Eurocode 4 (1994). From the experimental study, it was determined that the confinement effect of circular steel tubes filled with high content flyash concrete was better than that of specimens filled with ordinary Portland cement concrete. The 5.88-mm-thick steel tube filled with 100% flyash concrete was equivalent in strength to a steel tube filled with C30 concrete at 28 days.

The Emerging Role of Chinese Transnational Corporations as Non-state Actors in Transnational Labour Law: A Case Study of Huayou Cobalt in the Global Cobalt Supply Chain

SI CHEN 서울대학교 사회발전연구소 2021 Journal of Asian Sociology Vol.50 No.1

This article aims to investigate the emerging role of Chinese transnational corporations in navigating labour norms in the context of global economic shifts. Based on a transnational labour law approach, this article conducts a case study on Huayou Cobalt, a transnational cobalt refiner headquartered in China. Since being targeted in a research report by Amnesty International in 2016, Huayou Cobalt has shown a proactive engagement with other actors along the global cobalt supply chain, as well as a rapid update of its social responsibility related corporate policies. By investigating recent regulatory updates made by Huayou Cobalt, this case study demonstrates that normative settling and behavior changes regarding labour regulation have emerged at Huayou Cobalt during the period between 2016 and 2020. Furthermore, this case study suggests that regulatory updates made by Huayou Cobalt could create both challenges and opportunities for developing a responsible global cobalt supply chain.

Establishment of Paclitaxel-resistant Breast Cancer Cell Line and Nude Mice Models, and Underlying Multidrug Resistance Mechanisms in Vitro and in Vivo

Chen, Si-Ying,Hu, Sa-Sa,Dong, Qian,Cai, Jiang-Xia,Zhang, Wei-Peng,Sun, Jin-Yao,Wang, Tao-Tao,Xie, Jiao,He, Hai-Rong,Xing, Jian-Feng,Lu, Jun,Dong, Ya-Lin Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.10

Background: Breast cancer is a common malignant tumor which affects health of women and multidrug resistance (MDR) is one of the main factors leading to failure of chemotherapy. This study was conducted to establish paclitaxel-resistant breast cancer cell line and nude mice models to explore underlying mechanisms of MDR. Methods: The breast cancer drug-sensitive cell line MCF-7 (MCF-7/S) was exposed in stepwise escalating paclitaxel (TAX) to induce a resistant cell line MCF-7/TAX. Cell sensitivity to drugs and growth curves were measured by MTT assay. Changes of cell morphology and ultrastructure were examined by optical and electron microscopy. The cell cycle distribution was determined by flow cytometry. Furthermore, expression of proteins related to breast cancer occurrence and MDR was tested by immunocytochemistry. In Vivo, nude mice were injected with MCF-7/S and MCF-7/TAX cells and weights and tumor sizes were observed after paclitaxel treatment. In addition, proteins involved breast cancer and MDR were detected by immunohistochemistry. Results: Compared to MCF-7/S, MCF-7/TAX cells had a higher resistance to paclitaxel, cross-resistance and prolonged doubling time. Moreover, MCF-7/TAX showed obvious alterations of ultrastructure. Estrogen receptor (ER) expression was low in drug resistant cells and tumors while expression of human epidermal growth factor receptor 2 (HER2) and Ki-67 was up-regulated. P-glycoprotein (P-gp), lung resistance-related protein (LRP) and glutathione-S-transferase-${\pi}$ (GST-${\pi}$) involved in the MDR phenotype of resistant cells and tumors were all overexpressed. Conclusion: The underlying MDR mechanism of breast cancer may involve increased expression of P-gp, LRP and GST-${\pi}$.

Detection of Abrupt Changes in Precipitation Extremes over South Korea Using a Bayesian Approach

Chen, Si,Shin, Ji-Yae,Kim, Tae-Woong 대한토목학회 2016 대한토목학회 학술대회 Vol.2016 No.10