Reactive oxygen species (ROS) can be produced by interactions between sunlight and light-absorbing substances in natural water environments and can completely destroy various organic pollutants in waste water. In this study, we used graphene oxide modified Ag2Se nanoparticles to enhance photochemically generated oxygen (PGO) species activity. Surface area and pore volumes of the Ag2Se-graphene (Ag2Se-G) samples showed catastrophic decrease due to deposition of Ag2Se. The generation of reactive oxygen species was detected through the oxidation reaction of DPCI to DPCO. The photocurrent density and the PGO effect increase in the case of the use of modified graphene. The PGO effect of the graphene modified with Ag2Se composites increased significantly due to a synergetic effect between graphene and the Ag2Se nanoparticles. The photocatalytic activity of sample was evaluated by measuring the degradation of organic pollutants such as methylene blue (MB) and industrial dyes such as Texbrite BA-L (TBA) under visible light.

본 연구의 목적은 신흥시장 내 기업집단의 국제화 및 성과간 관계를 조명하는데 있다. 또한 국제 화의 경험이 기업의 성과에 영향을 미칠 수 있다는 가능성 하에 국제화로 인한 학습효과가 있는지 를 밝히고자 한다. 주식시장에 상장되어 있는 409개의 제조기업을 대상으로 시행된 실증에서, 본 연구는 첫째, 최소한 기업성과를 바탕으로 드러난 결과를 볼 때, 적어도 한국의 신흥시장 기업집단 만큼은 국제화로 인한 혜택을 크게 보지 못한 것으로 나타났다 (이는 U자형 성과-국제화 관계를 보여준 개별기업의 결과와 배치된다). 둘째, 기업성과와 국제화 경험간 관계와 관련하여, 신흥시장 의 기업집단에서는 유의미한 관련증거를 발견할 수 없었던 반면, 개별기업에서는 S자 형태의 상관 성을 목격할 수 있었다. 전체적인 관점에서, 본 결과들은 신흥시장 기업집단의 경우, 국제경영을 행함에 있어 고유의 기업특성을 보유하고 있다고 추측되며, 따라서 향후 미래연구에서는 기존 선행 연구에서 간과한 영역, 즉 신흥시장 기업집단의 국제화와 성과를 측정함에 있어 기업의 고유특성이 어떠한 매개효과를 가지는지를 살펴볼 필요성이 제기된다.

Cylindrical shells are often used in ship structures at deck plating with a camber, side shell plating at fore and aft parts, and bilge structure part. It has been believed that such curved shells can be modelled fundamentally by a part of a cylinder under axial compression. From the estimations with the usage of cylinder models, it is known that, in general, curvature increases the buckling strength of a curved shell subjected to axial compression, and that curvature is also expected to increase the ultimate strength. We conduct series of elasto-plastic large deflection analyses in order to clarify the fundamentals in buckling and plastic collapse behaviour of cylindrical shells under axial compression. From the numerical results, we derive design formula for predicting the ultimate strength of cylindrical shell, based on a series of the nonlinear finite element calculations for all edges, simply supporting plating, varying the slenderness ratio, curvature and aspect ratio, as well as the following design formulae for predicting the ultimate strength of cylindrical shell. From a number of analysis results, fitting curve can be developed to use parameter of slenderness ratio with implementation of the method of least squares. The accuracy of design formulae for evaluating ultimate strength has been confirmed by comparing the calculated results with the FE-analysis results and it has a good agreement to predict their ultimate strength.