Surface Texture Transformation in Micro-Cutting of AA6061-T6 with the Rehbinder Effect

Jiayi Zhang,Yan Jin Lee,Hao Wang 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.8 No.4

The Rehbinder effect (R-effect) on microcutting has been successful to augment machinability of ductile metals; however, there is a lack in understanding of its influence on texture evolution in the machined surfaces. This study validates the R-eff ect on AA6061-T6 and characterises the influence of the R-effect on the texture transformation in the machined surface. Microhardness tests reveal that the R-effect produces softer surfaces (87–96 HV) as compared with the surfaces produced conventionally (96–108 HV), which is attributed to the differences in grain types. A large fraction of substructured grains (96.4%) exists in the surfactant-affected subsurface while a higher proportion of deformed grains (42.8%) forms during conventional microcutting. In addition, the main texture components of the conventionally produced surface are Cube, Goss and S textures, which differ from the dominant volumes of Copper and R textures under the R-effect. The differences are results of the stress states induced during microcutting, which is exemplified through numerical simulations that consider the reduction in fracture toughness of the material with the R-effect. The advanced understanding of the R-effect better positions the use of surfactants as a cleaner near-dry metalworking fluid.

중국 상장 회사의 ESG 성과가 기업가치에 미치는 영향 - 기관투자자 지분 및 환경보호세의 매개효과

주가흘(Jiayi Zhou),언초(Chao Yan),송니은(Nieun Song),최성진(Seongjin Choi) 한국경영학회 2023 한국경영학회 통합학술발표논문집 Vol.2023 No.8

ESG 성과와 기업가치의 관계에 대한 기존 연구는 많지만, 그중에서 환경보호세와 기관투자자 지분이 기업 가치에 미치는 영향에 대한 기존 연구 결과의 차이가 크다. 기존 ESG 성과와 환경보호세, 기관투자자 지분에 관한 연구가 적어 환경보호세의 인센티브 효과가 중국 시장에서 실제로 얼마나 효과가 있는지가 불분명하다. 따라서 본 연구는 기업가치가 ESG 성과에 미치는 영향을 깊게 이해하기 위해 중국 상장 기업의 ESG 성과와 환경보호세 및 기관투자자 지분 간의 관계를 중점적으로 연구한다. 본 연구는 2018년부터 2021년까지 중국 A주 상장 회사 중 172개 제조업 기업의 재무 정보를 수집하여 ESG 성과가 기업가치에 미치는 영향을 분석한다. 결과적으로 다른 조건이 일정한 경우 높은 ESG 성과는 기업의 지속 가능성을 높이고 이해 관계자와 투자자의 의사 결정에 긍정적인 영향을 미칠 것으로 보인다. 둘째, 중국 A주 상장 회사 제조업이 발전하는 과정에서 ESG 성과의 증가는 상장 회사에 대한 기관의 투자액을 효과적으로 높이고 해당 기업의 환경보호세 납부액을 낮춰 기업가치를 높이는 것으로 나타났다. 마지막으로 ESG 성과가 기업가치를 높이는 촉진 효과가 상장 회사 중국유기업과 규모가 큰 회사 중 더욱 두드러진다는 사실이 드러났다. There are many existing studies on the relationship between ESG performance and corporate value, but among them, there is a large gap between the results of previous studies on the effect of environmental protection tax and institutional investor equity on corporate value. It is unclear how effective the incentive effect of the environmental protection tax actually is in the Chinese market, as there are few studies on existing ESG performance, environmental protection tax, and institutional investor equity. Therefore, this study focuses on the relationship between ESG performance of Chinese listed companies, environmental protection tax and institutional investor equity in order to deeply understand the impact of corporate value on ESG performance. This study analyzes the impact of ESG performance on corporate value by collecting financial information of 172 manufacturing companies among Chinese A-share listed companies from 2018 to 2021. The results suggest that, other things being equal, high ESG performance is expected to enhance corporate sustainability and positively influence the decision-making of stakeholders and investors. Second, in the course of the development of Chinas A-share listed company manufacturing, an increase in ESG performance effectively increases institutional investment in listed companies, lowers the amount of environmental protection tax payments of the companies, and increases corporate value. Finally, it was found that the facilitating effect of ESG performance on corporate value was more pronounced among state-owned and large-scale listed companies.

Intelligent computational design of scalene-faceted flat-foldable tessellations

Chen Yao,Lu Chenhao,Yan Jiayi,Feng Jian,Sareh Pooya 한국CDE학회 2022 Journal of computational design and engineering Vol.9 No.5

Origami tessellations can be folded from a given planar pattern into a three-dimensional object with specific geometric properties, inspiring developments in various fields of science and engineering such as deployable structures, energy absorption devices, reconfigurable robots, and metamaterials. However, the range of existing origami patterns with functional properties such as flat-foldability is rather scant, as analytical solutions to constraint equations arising in the design process are generally highly complicated. In this paper, we tackle the challenging problem of automated design of scalene-faceted flat-foldable origami tessellations using an efficient metaheuristic algorithm. To this end, this study establishes constraint curves based on compatibility conditions for all six-fold (i.e., degree-6) vertices. Subsequently, a graphical method and a particle swarm optimization (PSO) method are adopted to produce optimal origami patterns. Moreover, mountain-valley assignments for the obtained geometric designs are determined using a computational approach based on mixed-integer linear programming. It turns out that the flat-foldable internal vertices of each C2-symmetric unit fragment (UF) exist as C2-symmetric pairs about the centroid of the UF. Furthermore, numerical experiments are carried out to examine the feasibility and compare the accuracy, computational efficiency, and global convergence of the proposed methods. The results of numerical experiments demonstrated that, in comparison with the graphical method, the proposed PSO method has not only a higher accuracy but also a significantly lower computational cost, enabling us to develop an intelligent computational platform to efficiently design scalene-faceted flat-foldable origami tessellations.

Comparative transcriptome analyses provide insights into the adaptation mechanisms to acute salt stresses in juvenile Sinonovacula constricta

Bin Ma,Zhaoshou Ran,Xiaorong Xu,Jilin Xu,Kai Liao,Jiayi Cao,Xiaojun Yan 한국유전학회 2019 Genes & Genomics Vol.41 No.5

Background Sinonovacula constricta is an economically important bivalve species in China, Korea and Japan that widely resides in estuarine and coastal areas where salinity fluctuates rapidly. However, little is known about its adaptation mechanisms to acute salt stresses. Objective To reveal the underlying molecular mechanisms involved in acute salt stresses in juvenile S. constricta. Methods Nine cDNA libraries (triplicate each trial) were established from juvenile S. constricta, which were subjected to low salinity (5 psu), optimal salinity (15 psu) and high salinity (25 psu) for 6 h, respectively. Results Illumina sequencing generated 478,587,310 clean reads totally, which were assembled into 427,057 transcripts of 246,672 unigenes. Compared with the control, 1259 and 2163 differentially expressed genes (DEGs) were identified under acute low and high salt stresses, respectively. GO and KEGG enrichment analyses of DEGs revealed that several key metabolic modulations were mainly responsible for the acute salt stresses. According to the significantly highlighted KEGG pathways, some key DEGs were identified and discussed in details. Notably, based on which, some potential osmolytes were further speculated. Conclusion Here, we carried out a unique report of comparative transcriptome analyses in juvenile S. constricta in response to acute salt stresses. The identified DEGs and their significantly enriched GO terms and KEGG pathways were critical for understanding and further investigating the underlying the physical and biochemical performances, and ultimately facilitated S. constricta breeding. Besides, the transcriptome data greatly enriched the genetic information of S. constricta, which were valuable for promoting its molecular biology researches.