• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.298-299
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• 2014

The solution of transient response of complex stiffness system was obtained using a green function of this system. To derive the green function, governing equation of this systems was expressed in Steady Space and solved by the diagonalization. The solution of this system are written as a convolution integral form. The result that are calculated by the numerical integration process for transient responses was showed properly.

• 한국표면공학회지
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• 제39권3호
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• pp.121-128
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• 2006

A set of Quartz Crystal Microbalances (QCM's) was used to observe the film removal characteristics of three different $CO_2-nitric$ acid microemulsions. QCM's electroplated with nickel or copper were used as specimens. F-AOT, NP-4 and the newly synthesized Proline Surfactant-1 were used as surfactants to create microemulsions. While the F-AOT microemulsion yielded a relatively low removal rate, that of the Proline Surfactant-1 completely removed the Cu metal film within a short period of time. The NP-4 microemulsion removed the metal surface. However, removal rate measurements per QCM were not possible due to the instability of the microemulsion when Cu ions were present in the nitric solution. The reaction kinetics and metal removal capabilities of microemulsions formed by the different surfactants are explained along with the characteristics of reverse micelles.

• 지구물리와물리탐사
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• 제3권1호
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• pp.13-18
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• 2000

적분방정식 전자탐사 모델링에서 종종 애매모호하게 받아 들여온 특이 요소에 대한 Green 텐서 적분을 명확히 해결하고자, 전자탐사 적분방정식에서의 특이치의 개념을 전자기 이론에서 사용되는 전기장의 적분식 표현에서의 특이치 문제와의 비교를 통해 설명하였다. 또한 적분방정식 전자탐사 모델링에서 수치해의 정확도를 좌우하는 가장 중요한 요소인 특이 적분을 3차원, 2.5차원 및 2차원, 그리고 얇은 판 적분방정식의 경우에 대해 유도하고 정리하였다.

• 한국염색가공학회지
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• 제24권4호
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• pp.247-252
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• 2012

The objective of this study was to find an appropriate method and process for protecting the green color in bamboo leaves and subsequent extraction of the green colorants, chlorophyll. Various inorganic salts including cupric sulfate, ferric sulfate, and zinc chloride were employed as green color protectors. Accordingly, the effects of metal salts and treatment conditions on color protection were investigated to find appropriate protector and conditions. And also, the efficacy of bamboo colorants as a natural green dye was evaluated through dyeing and colorfastness tests. Antimicrobial activity of dyed fabrics was measured by shake flask method in terms of bacterial reduction rate using Staphylococcus aureus(ATCC 6538). On the basis of experimental results for stabilizing bamboo leaves colorants, it was confirmed that Cu was the most appropriate metal type considering dye uptake, photostability and light fastness, and its optimum concentration was 0.025%. After the stabilization, the colorants were extracted efficiently at NaOH aqueous solution of 1.00%. It was concluded that bamboo leave has a high potentiality as new resources to produce a natural green dye with antimicrobial functionality.

• Earthquakes and Structures
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• 제3권3_4호
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• pp.507-518
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• 2012

It is now widely accepted that the resulting displacement field within elastic, inhomogeneous, anisotropic solids subjected to equipartitioned, uniform illumination from uncorrelated sources, has intensities that follow diffusion-like equations. Typically, coda waves are invoked to illustrate this concept. These waves arrive later as a consequence of multiple scattering and appear at "the tail" (coda, in Latin) of seismograms and are usually considered an example of diffuse field. It has been demonstrated that the average correlations of motions within a diffuse field, in frequency domain, is proportional to the imaginary part of Green's function tensor. If only one station is available, the average autocorrelation is equal to the average squared amplitudes or the average power spectrum and this gives the Green's function at the source itself. Several works address this point from theoretical and experimental point of view. However, a complete and explicit analytical description is lacking. In this work we study analytically some properties of the Green's function, specifically the imaginary part of Green's function for 2D antiplane problems. This choice is guided by the fact that these scalar problems have a closed analytical solution (Kausel 2006). We assume the diffusiveness of the field and explore its analytical consequences.

• The Journal of Asian Finance, Economics and Business
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• 제8권5호
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• pp.143-150
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• 2021

This study aims to determine (1) the inhibiting factors and solutions in the development of eco-tourism, and (2) how green entrepreneurship can be used for eco-tourism development. The increasing issue of global warming is pushing awareness of environmental preservation. This condition changes the people's paradigm in traveling from the concept of mass-tourism to the concept of eco-tourism. The development of eco-tourism has consequences for entrepreneurial activities which is known as green entrepreneurship. This study is applied research conducted in East Lombok, one of the regions in Indonesia. The sampling technique used is purposive sampling covering a total of 34 informants. Data collection methods are carried out through interviews, observation, and documentation studies. Based on the data analysis, the findings of this study show that (a) inhibiting factors of eco-tourism development are limitation of eco-tourism knowledge, lack of awareness in environmental preservation, and absence of supporting government policy; and (b) solution for eco-tourism development discovered in this research is divided into five factors i.e., condition, demand, related industry and support, strategy, government. Besides, for applying the green entrepreneurship model i.e., developing the spirit of green entrepreneurship, training in making products and services that are environmentally friendly is needed.

• 신재생에너지
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• 제18권2호
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• pp.50-59
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• 2022

The Korean government announced the "1st Basic Plan for the Transition to Hydrogen Economy" in 2021 and declared the establishment of a hydrogen industry ecosystem by 2040. To build a low-carbon power system, resources that can efficiently accommodate renewable energy are required, and green hydrogen is considered a potential solution. This study analyzed the economic feasibility of green hydrogen-based sector coupling to reduce curtailment of renewable generation in the Jeju power system by 2025 under the scenario of with or without HVDC#3. The result showed that HVDC#3 significantly reduced the frequency of curtailment from 16.1% to 3.0%. In addition, green hydrogen-based sector coupling was an economically feasible option as result showed an IRR of 4.86% when HVDC#3 was connected and 11.45% when it was not under the condition of achieving 50% curtailment reduction. This study shows that the higher the level of renewable energy deployment, the more delayed the HVDC connection between Jeju and the main land, and the lower the SMP, the more economically feasible the green hydrogen-based sector coupling is. Furthermore, this study suggests that the policy goal of completely reducing curtailment is not economically efficient.

• 한국재료학회지
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• 제33권7호
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• pp.315-322
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• 2023

In the present work, we address the new route for the green synthesis of manganese dioxide (MnO₂) by an innovative method named the solution plasma process (SPP). The reaction mechanism of both colloidal and nanostructured MnO₂ was investigated. Firstly, colloidal MnO₂ was synthesized by plasma discharging in KMnO₄ aqueous solution without any additives such as reducing agents, acids, or base chemicals. As a function of the discharge time, the purple color solution of MnO₄^- (oxidation state +7) was changed to the brown color of MnO₂ (oxidation state +4) and then light yellow of Mn²⁺ (oxidation state +2). Based on the UV-vis analysis we found the optimal discharging time for the synthesis of stable colloidal MnO₂ and also reaction mechanism was verified by optical emission spectroscopy (OES) analysis. Secondly, MnO₂ nanoparticles were synthesized by SPP with a small amount of reducing sugar. The precipitation of brown color was observed after 8 min of plasma discharge and then completely separated into colorless solution and precipitation. It was confirmed layered type of nanoporous birnessite-MnO₂ by X-ray powder diffraction (XRD), fourier-transform infrared spectroscopy (FT-IR), and electron microscopes. The most important merits of this approach are environmentally friendly process within a short time compared to the conventional method. Moreover, the morphology and the microstructure could be controllable by discharge conditions for the appropriate potential applications, such as secondary batteries, supercapacitors, adsorbents, and catalysts.

• 한국해양공학회지
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• 제11권2호
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• pp.77-90
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• 1997

Wave deformation due to Oscillating water column (OWC) plant was studied. To solve this problem, three dimensional numerical method based on Improved Green integral equation was applied. Method condition was considered as well as fixed condition and freely floating condition. From the calculation results, main characteriatic of wave deformation due to OWC plant were discussed. Also, some calculations for the floating barge were performed to confirm the validity of numerical solution of the method.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1995년도 Proceedings of the Korea Automation Control Conference, 10th (KACC); Seoul, Korea; 23-25 Oct. 1995
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• pp.275-278
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• 1995

In this paper, we consider a dynamic shape control problem with an example of controlling a flexible beam shape. Mathematical formulations are obtained by employing the Green's function approach. Necessary conditions for optimality are derived by considering the quadratic performance criteria. Numerical results for both of the dynamic and the static cases are obtained and compared.