• Journal of the Korean Society of Industry Convergence
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• v.24 no.6_2
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• pp.745-751
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• 2021

The International Maritime Organization(IMO) has established Emission Control Areas(ECA) in the Baltic Sea, North Sea, and sea areas in the United States since 2012, and encourages the use of clean fuels such as Natural Gas(NG). To keep pace with the increase in international demand for LNG bunkering vessels, research for the localization of key equipment for LNG bunkering must also be performed in Korea. For research and development of core bunkering equipment and systems, in this study, heat transfer analysis and structural analysis were performed by modeling the saddle, which must first be secured structurally by directly receiving the load of the hose. As a result, the suitability of the model was reviewed by analyzing the temperature distribution and stress level through the analysis results of this study.

• Journal of Plant Biotechnology
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• v.50
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• pp.207-214
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• 2023

Lindera obtusiloba (Lauraceae) is a dioecious tree that is widely distributed in the low-altitude montane forests of East Asia, including Korea. Despite its various pharmacological properties and ornamental value, the genetic diversity and population structure of this species in Korea have not been explored. In this study, we selected 6 nuclear and 6 chloroplast microsatellite markers with polymorphism or clean cross-amplification and used these markers to perform genetic diversity and population structure analyses of L. obtusiloba samples collected from 20 geographical regions. Using these 12 markers, we identified a total of 44 alleles, ranging from 1 to 8 per locus, and the average observed and expected heterozygosity values were 0.11 and 0.44, respectively. The average polymorphism information content was 0.39. Genetic relationship and population structure analyses revealed that the natural L. obtusiloba population in Korea is composed of 2 clusters, possibly due to two different plastid genotypes. The same clustering patterns have also been observed in Lindera species in mainland China and Japan.

• Journal of Energy Engineering
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• v.27 no.2
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• pp.1-13
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• 2018

The proportion of natural gas-fueled power generation is expanding due to the change of domestic energy policy pursuing reduction of dust and increasing clean energy consumption. Natural gas fuels used for the combined-cycle power plants and the district-heating power plants are operated at high temperature and high pressure in the fuel supply system. Accidents due to leakage of the gas such as fire and explosion should be prevented by applying risk management techniques. In this study, risk assessment was performed on the natural gas fuel supply system of a combined power plant based on the API RP 581 RBI code. For the application of the API RBI code, lines and segments of the evaluation target system were identified. Operational data and input information were analyzed for the calculations of probability of failure and consequence of failure. The results of the risk assessment were analyzed over time from the initial installation time. In the code-based evaluation, the gas fuel supply system was mainly affected by thinning, external damage, and mechanical fatigue damage mechanisms. As the operating time passes, the risk is expected to increase due to the external damage caused by the CUI(Corrosion Under Insulation).

• Journal of Conservation Science
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• v.28 no.1
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• pp.21-27
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• 2012

In the Chosun period, the noble class usually buried the dead bodies in the lime-covered tomb. Recently their costumes are excavated while maintaining the shape. However, the textiles discovered from the inside have been degradated by a body and moisture. To conserve these textiles one of the most important thing is how to clean these textiles right after the excavation. The purpose of this study is to examine the effects of wet cleaning to minimize the color change of textile remains. For this purpose, silk and cotton were dyed with natural dyes (7 red, 1 blue, 6 yellow, 4 green and 4 purple colors), then they were kept for 6 months with pork meat at $10^{\circ}C$, and were washed by four cleaning solutions (water, anionic surfactant (SDS), non-ionic surfactant (Triton X-100) and natural surfactant (saponin)) at $20^{\circ}C$ and $40^{\circ}C$. The color change was evaluated by color difference (${\Delta}E$) between non-treated and after washed samples. From the results, it was found that the color changes are significantly different depending on the washing temperature, textile material, the cleaning agents and the type of dyes.

• Korean Journal of Ichthyology
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• v.27 no.4
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• pp.300-305
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• 2015

The characteristics of 11 spawning sites in the natural environment of the Korean endemic species, Liobagrus somjinensis were investigated in the Yocheon (stream) of Seomjingang (river), located in Sikjeong-dong, Namwon-si, Jeollabuk-do, Korea from May to June 2015. The spawning sites had largely two parts, the upper region close to the surface of the waters and under region at bottom: the upper part was covered with a large and flat boulder over about 256 mm in size, whereas the under part consisted mainly of pebbles and sand. The large boulder put on the upper region may be seen as a bulwark for guarding eggs laid at the under (bottom) region. All the sites under the boulder showed a similar structure having a small hollow filled with an egg mass and an individual (male). The spawning bottoms left clean having no any benthic invertebrates and detritus. The egg shape was spherical, yellow and covered with a transparent membrane and the egg size was $3.31{\pm}0.15mm$ (n=30) in diameter. The development stage of each egg mass under the boulder was almost same from morula stage to formation stage of eye lens. The average number of eggs in 11 spawning sites was $121{\pm}35.5$ (84~176) and the average number of female fecundity in ovary was $143{\pm}31.3$ (110~232).

• Journal of the Korean Society for Marine Environment & Energy
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• v.6 no.2
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• pp.3-15
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• 2003

Recently more than 450 incidents of oil spill a year have occurred in nearshore of Korea, which caused unmeasurelable losses in fisheries and severe damage in marine ecosystem. Two approaches remain paramount in any response to marine oil spill : the enhancement of natural dispersion of the oil by using dispersants, and mechanical recovery using booms and skimmers. A technique currently receiving fresh attention is the enhancement of the natural bioremediation of oil through the application of micro-organisms and/or nutrient. Oil, like many natural substances, will biodegrade over a period of time into simple compounds such as carbon dioxide, water and biomass. Bioremediation is the term used to describe a range of processes which can be used to accelerate natural biodegradation. More specifically biostimulation is the application of nutrients, and bioaugremetation or seeding is the addition of microbes specially selected to degrade oil. Bioremediation is an economically attractive method for the clean-up of oil-contaminated area. Bioremediation has been demonstrated to be an effective oil spill countermeasure for use in cobble, sand beach, salt marsh, and mud flat environment.

• Journal of the Korean Applied Science and Technology
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• v.36 no.3
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• pp.915-929
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• 2019

This study attempted to investigate the effects of natural henna-treated permanent wave on degree of damage and morphological changes of hair. For this, amino acid was analyzed, and hair thickness and surface were observed through SEM. In addition, hair curl formation & retention, methylene blue coloring, tensile strength and elongation were measured. The results found the followings: Total amino acid contents rose as the number of natural henna treatment increased, hair protection effects are expected. In terms of curl formation, in an experimental group hair became more elastic as the number of natural henna treatment increased, compared to a control group. In both control and experimental groups, hair retention decreased as shampooing frequency increased because of extension of (C) and (C)', According to analysis of hair thickness using SEM, hair became thick in an experimental group after natural henna treatment, compared to a control group. In morphological observation of hair surface, it was mostly clean, and cuticle was tidy and healthy. In methylene blue coloring, as the number of natural henna treatment increased, absorbance went up. In addition, tensile strength declined in an experimental group, compared to a control group. As the number of natural henna treatment increased, elongation in an experimental group increased, compared to a control group. The above results show that as the number of natural henna treatment increased, hair became thicker, and curl formation and retention improved. In addition, hair elasticity and flexibility were enhanced, reducing a risk of hair damage. Therefore, the study results would be available as basic data in reducing scalp and hair damage, proposing the natural henna treatment as a method to reduce hair damage from chemical perm in cosmetology industry.

• Clean Technology
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• v.21 no.3
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• pp.141-152
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• 2015

As environmental issues are emerging, bio-plastic suppliers in leading countries have been foreseeing the strong needs for environment-friendly materials such as eco-packing materials due to increased attention and regulation on recycle. To catch up with the demand, various types of bio-plastics based on natural feedstocks were developed and released on a market. These bio-plastic products drew the great attention even in domestic industries. At present, international oil price fluctuation and heavy charge on waste raise the unit cost of production and disposal expense of conventional plastic materials. These conditions make bio-plastic an alternative, because it is not restrained by oil prices and problem in the disposal. It is also expected that bio-plastic will be applied to various types of products including containers, industrial supplies, disposables, and medical supplies. However, the bio-plastic is still in its infancy, thus more research and understanding should be followed to put it to application. Bio-plastic is considered as environment-friendly material with high potential which has the advantages of production and disposal.

• Clean Technology
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• v.26 no.1
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• pp.55-64
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• 2020

According to the Korean Renewable Energy 3020 Implementation Plan, the installation capacity of renewable energy is expected to increase whereas technology for storing excess electricity and stabilizing the power supply of renewable energy sources is extremely required. Power-to-Gas is one of energy storage technologies where electricity is converted into gas fuel such as hydrogen and methane. Basically, Power-to-Gas system could be effectively utilized to store excess electricity generated by an imbalance between supply and demand. In this study, the economic feasibility analysis of Power-to-Gas reflecting the domestic situation was carried out. Total revenue requirement method was utilized to estimate the levelized cost of hydrogen. Validation on the economic analysis method in this study was conducted by comparison of the result, which is published by the International Energy Agency. The levelized cost of hydrogen of a 100-MW Power-to-Gas system reflecting the current economic status in Korea is 8,344 won kg^-1. The sensitivity analysis was carried out, applying the main analysis economic factors such as electricity cost, electrolyser cost, and operating year. Based on the sensitivity analysis, the conditions for economic feasibility were suggested by comparing the cost of producing hydrogen using renewable energy with the cost of producing natural gas reformed hydrogen with carbon capture and storage.

• Clean Technology
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• v.26 no.1
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• pp.65-71
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• 2020

Various solar hybrid energy conversion processes, which have both the advantages of renewable energy sources and fossil energy sources, have been developed in the world because stable and predictable energy supplies, such as electricity and natural gas, are necessary for modern societies. In particular, a solar hybrid energy conversion process based on a dual fluidized bed process concept has been expected as the promising solution for sustainable energy supply via thermochemical conversions, such as pyrolysis, combustion, gasification, and so on, because solar thermal energy could be captured and stored in fluidized bed materials. Therefore, the attrition and heat transfer characteristics of silicon carbide and alumina particles used for fluidized bed materials for the solar hybrid energy conversion process were studied in an ASTM D5757 reactor and a bubbling fluidized bed reactor with 0.14m diameter and 2m height. These characteristics of novel fluidized bed materials were compared with those of sand particles which have widely been used as a fluidized bed material in various commercial fluidized bed reactors. The attrition resistances of silicon carbide and alumina particles were higher than those of sand particles while the average values of heat transfer coefficient in the bubbling fluidized bed reactor were in the range of 125 ~ 152 W m^-2K^-1.