• Clean Technology
• /
• v.25 no.3
• /
• pp.256-262
• /
• 2019

Hydroxylammonium nitrate (HAN)-based liquid propellants are attracting attention as environmentally friendly propellants because they are not carcinogens and the combustion gases have little toxicity. The catalyst used to decompose the HAN-based liquid propellant in a thruster must have both low temperature activity and high heat resistance. The objective of this study is to prepare an Ru/alumina/metal foam catalyst by supporting alumina slurry on the surface of NiCrAl metal foam using a washing coating method and then to support a ruthenium precursor thereon. The decomposition activity of a HAN aqueous solution of the Ru/alumina/metal foam catalyst was evaluated. The effect of the number of repetitive coatings of alumina slurry on the physical properties of the alumina/metal foam was analyzed. As the number of alumina wash coatings increased, mesopores with a diameter of about 7 nm were well-developed, thereby increasing the surface area and pore volume. It was optimal to repeat the wash coating alumina on the metal foam 12 times to maximize the surface area and pore volume of the alumina/metal foam. Mesopores were also well developed on the surface of the Ru/alumina/metal foam catalyst. It was found that the metal form itself without the active metal and alumina can promote the decomposition reaction of the HAN aqueous solution. In the case of the Ru/alumina/metal foam-550 catalyst, the decomposition onset temperature was significantly lowered compared with that of the thermal decomposition reaction, and ${\Delta}P$ could be greatly increased in the decomposition of the HAN aqueous solution. However, when the catalyst was calcined at $1,200^{\circ}C$, the catalytic activity was lowered inevitably because the surface area and pore volume of the catalyst were drastically reduced and Ru was sintered. Further research is needed to improve the heat resistance of Ru/alumina/metal foam catalysts.

• Korean Journal of Heritage: History & Science
• /
• v.47 no.4
• /
• pp.22-47
• /
• 2014

This study was to understand the basic principles of the East Asian wooden structure system research and analysis. The Korea and China ancient architecture internal structure research that the combination of girders and crossbeams position. The ancient wooden structures of eastern Asian countries, Korea and China are not much different from each other in the principles of the wooden architecture structure, combining pillars, purlins and crossbeams. However, it seems that age-division, local-division, national-division differs in detail techniques. China ancient wooden structures combination of purlin and crossbeam, and So-seul Timber(Chinese name: Chashou叉手, Tuojiao 托脚) seems to show differences according to the age of the fulcrum position, detailed approach is also different according to various historical dynasty. Before in the 15th century, Purlin and Crossbeam are coupled to each other, but since the 15th century, seems to have developed a technique combined with each other Girder and Crossbeam and to prevent buckling of the Crossbeam cross-sectional area increased dramatically. For Tuojiao in China Tang-Wudai dynasty(A.D. 618~979), can see that saw the top position Girder and Tuojiao no direct coupling, can be seen as maintaining the safety of the material than the material of the inner wooden structures prevent buckling of the purlin. Korea ancient wooden structures of Goryeo dynasty(A.D. 918~1391), So-seul Timber(Chinese name Tuojiao) why do not to use the fashion? To use Purlin Lower backing material techniques to prevent buckling is a popular trend to stable can be thought of as a preferred way to maintain. I think that with universality beyond the local-division, national-division and the two countries since the 15th century of Korea and China ancient wooden structures detailed mechanism for the purlin buckling. In middle-late Chosen dynasty, The effect of Deotgeolyi- techniques and fleeting beams reduce the purlin buckling that reduces the load transmitted from purlin and crossbeam of how to reduce the load on the roof portion of the architecture fleeting beams used, which of craftsmanship of the Chosen Dynasty building can be referred to as another technique for preventing buckling purlin. This Korea and China ancient architecture purlin beam structure and material So-seul Timber study. Seems to be able to provide a basic research study to restore and designed the old wooden architectures.

• Management & Information Systems Review
• /
• v.38 no.2
• /
• pp.67-81
• /
• 2019

In accordance with K-IFRS 1109, financial instruments are classified to amortized cost (AC), fair value through other comprehensive income (FVOCI) and fair value through profit or loss (FVPL). And disposal gains are prohibited to be recirculated for net income when FVOCI financial instruments would be sold in the future, so-called recirculation prohibition. This research investigates whether accumulated other comprehensive income of available-for sale financial assets(AFS) under K-IFRS 1039, could affect reclassified amounts to the FVPL securities from the AFS securities. Also, this study investigates the effects of the reported income on the reclassified FVPL, because CEOs are likely to try earnings management when net income is predicted to be less than target or is low, comparing other firms. As a result of empirical analysis, first, I find that accumulated other comprehensive income of the AFS has a positive impact on the reclassified FVPL. Second, level of reporting income has no significant impact on the reclassified FVPL. Third, interaction effects are significantly positive on the firms which have more other comprehensive income and less level of reported income. Fourth, the effects of the bank and securities are more distinct than those of the manufactures. This study is the first research to investigate earnings management through AFS at the timing of the first adoption of K-IFRS 1109. Empirical results of this study provide evidence of earnings management on the reclassification of FVPL which gives meaningful implications to regulators, academic researchers and auditors.

• Korean Journal of Heritage: History & Science
• /
• v.37
• /
• pp.327-348
• /
• 2004

In this study, after analyzing several local climate characteristics of South Korea, I validated distribution, invasion, foraging, underground activities, attack season as ecological characteristics and also temperature, relative humidity, and tree species as preference characteristics of Korean termites (Reticulitermes speratus kyushuensis Morimoto). Especially, southern part of the Korean peninsula is a suitable area for inhabitation and motion of termites holding same ecological characteristic like R. speratus kyushuensis. Busan is a neighboring district at field distribution north limiting temperature of Coptotermes formosanus Shiraki and Chuncheon is a passing area through the Korean Peninsula of field distribution north limiting temperature of Reticulitermes speratus Kolbe. The termite attack of wood devices was about 34.5% for 3 years in the forest of Jongmyo. Although the attack rate of termite increased each year, the detection rate decreased and the missing rate was high by degrees. I confirmed a foraging habits which is a part of termite colony was a role of continuous decomposition and another was a role of new food hunt as experimental results. The foraging termites were found under ground at Jongmyo in Seoul from April to November in the 2001 and the most active period was on July and August. The termite invasion rate of bait station increased in every monitoring. Through the increasing attack rate of bait station during 2nd monitoring (November, 2000) and 3rd monitoring(March, 2001), I confirmed that termites moved into the deep underground in winter, and were working continuously to forage. R. speratus kyushuensis inhabiting at the Korean Peninsula is a species which has food consumption rate with higher temperature. The termite revealed the greatest amount of food(filter paper) at $30^{\circ}C$(90% RH), but showed increasing death rate at over $32^{\circ}C$. Also, survival rate of this termite was 97% at 84% RH($30^{\circ}C$), but killed 100% at 52% RH($30^{\circ}C$) and 70% RH($30^{\circ}C$). For wood feeding, this was observed the preference in a pine tree(Pinus densiflora) above all others. Survival of termites was high(87%) at a pine tree, but low(13.5%) at a paulownia tree(Paulownia coreana). In this study, I presented the biological characteristic of termite(R. speratus kyushuensis Morimoto) and confirmed the deterioration degree of termite on wooden cultural heritage in Korea. Depending on climate and soil temperature, each area in the southern part of the Korea Peninsula, has some different active period and different distribution of R. speratus kyushensis. With these results, I expect that this report helps to prepare the integrated pest management(IPM) of the termite on wooden cultural heritage in Korea, and it may help to reduce the economical loss from termite damage in Korea.

• The Journal of Korean Academy of Prosthodontics
• /
• v.57 no.2
• /
• pp.127-133
• /
• 2019

Purpose: The purpose of present study was to investigate fracture strength and mode of failure of endodontically treated teeth restored with metal cast post-core system, prefabricated fiber post system, and newly introduced polyetherketoneketone (PEKK) post-core system. Materials and methods: A total of 21 mandibular premolar were randomly grouped into 3 groups of 7 each according to the post material. Group A was for metal cast post core; Group B for prefabricated glass fiber post and resin core; and Group C for milled PEKK post cores. All specimens were restored with metal crown. The fracture strength of each specimen was measured by applying a static load of 135-degree to the tooth at 2 mm/min crosshead speed using a universal testing machine. After the fracture strength measurement, the mode of failure was observed. The results were analyzed using Kruscal-Wallis test and post hoc Mann-Whitney U test at confidence interval ${\alpha}=.05$. Results: Fracture resistance of PEKK post core was lower than those of cast metal post and fiber reinforced post with composite resin core. In the aspect of fracture mode most of the root fracture occurred in the metal post core, whereas the post detachment occurred mainly in the fiber reinforced post. In the case of PEKK post core, teeth and post were fractured together. Conclusion: It is necessary to select appropriate materials of post for extensively damaged teeth restoration and clinical application of the PEKK post seems to require more research on improvement of strength.

• Korean Journal of Plant Resources
• /
• v.32 no.2
• /
• pp.160-169
• /
• 2019

The this study was carried out to investigate the growth characteristics of wild-simulated ginseng by direct seeding and transplanting cultivation for develop standard cultivation techniques of wild-simulated ginseng. Bonghwa experimental field were confirm to be suitable location environment for cultivation of wild-simulated ginseng. As a result of this study, the germination rate of wild-simulated ginseng was significantly highest when seed size was over 6.5 mm in the spot seeding cultivation. In the case of transplanting, survival rate was significantly increased when the diameter of root was over 10 mm, planting distance was 7 cm, and the thickness of soil covering was less then 2 cm. The result of growth characteristics of wild-simulated ginseng by cultivation type, growth of stem in spot seeding cultivation was showed significantly increased when seed size over 6 mm, seeding number was 3 grains, and the seeding distance was less then 5 cm. Strip seeding cultivation was showed significantly increased in stem and root growth when seeding distance was 30 cm grains and quantity of seeding was less then 23 g. In the case of transplanting cultivation, it's was showed significantly increased in stem growth when diameter of root was over then 10 mm and direction of rhizome was top and bottom. The results of this study was that to clearly establish the techniques of cultivation of managements and it's will be suggest contribute to the industrial activation of wild-simulated ginseng.

• Journal of the Society of Disaster Information
• /
• v.17 no.3
• /
• pp.442-453
• /
• 2021

Purpose: The objective of this study is to suggest desirable direction of Korean accident investigation organization by analyzing the operation status and way of overseas developed countries' investigation agency. Method: To accomplish the objective of this study, we were examined four main characteristics of accident investigation agencies of the U.S., Japan, and Sweden, focusing on (1); the background of the establishment, (2);organizational structure, (3);major tasks and functions, (4); accident investigation procedures. Result: First, the purpose of its establishment and task is to prevent recurrence of disasters and accidents, at the same time, administrating and researching duties such as legal system, policy, recommending improvement and conducting scientific disaster-cause analysis to contribute safety for the government. Second, it is operated as an independent organization under the president, not belonging to the ministry, in order to enable fair investigation in an impartial position. Third, it has the authority to be recognized for its expertise in the results of investigation. In other words, it is operated as a permanent organization with professional personnel, and secures authority through the accident research with indepth investigation and high-quality recommendations. Conclusion: The overseas investigation agencies rapidly manage and coordinate their operational practices in order to resolve national requirements and social conflicts with fairness, accuracy and expertise in accident investigations. In order to prevent the recurrence of similar events, Korea needs to efficiently reconstruct its investigative functions distributed by each government department. In addition, institutional improvement is needed to make general adjustments at the national level, organize and operate control tower for when the accident has happened.

• Korea Science and Art Forum
• /
• v.37 no.2
• /
• pp.239-250
• /
• 2019

Along with changes in the industrial structure, revitalizing decrepit or abandoned industrial-age infrastructures are actively under way on a global scale. This study was motivated by an interest in investigating currently idle industrial infrastructures and revitalizing the abandoned passenger ferry terminal in Geoje's Jangseungpo and surrounding areas. The main aims of this study were to examine regional features for the purpose of establishing urban renewal plans and field opinions of the local residents on how to proceed with the restoration of the passenger ferry terminal. To this end, this paper looked into previous case studies of converting decrepit industrial infrastructures into new cultural venues, depending on each region's special circumstances. This paper's findings are as follows: First, as a result of this investigation, the author found that in all cases in Korea and elsewhere revitalization focused on creating modern cultural spaces appropriate for the region while retaining its traditional value. At the same time, they sought sustainable cultural and economic revival. Second, as a result of the investigation on Geoje City's local characteristics, the author found that the surrounding areas' commercial districts were depressed after the terminal's closure. At the time of the investigation, the city government was trying to reopen the terminal as a major port offering multiple international ferry destinations while attracting tourists. Third, as a result of the surveys on the local residents, it was found that more than half of the residents were in agreement with the city government's plan to reopen the terminal and expressed their wishes that they want the terminal to have other uses such as cultural venues. Based on these research results, the author makes proposals, including expanding the passenger ferry terminal and offering cultural spaces within and near the terminal, based on the local residents' opinions and in reflection of local circumstances. As part of this effort, the author also recommends a new brand name and design plan for the new passenger ferry terminal so that Geoje City can improve its local community value.

• Journal of Nutrition and Health
• /
• v.54 no.5
• /
• pp.534-546
• /
• 2021

Purpose: This study aimed at understanding meal kit purchasing behavior and investigating its relationship with the Nutrition Quotient (NQ) of young adults. Methods: We conducted a survey on adults in their 20s and 30s covering their meal kit purchase experience, satisfaction, recognition, and purchase intention, and examined the relationship between the meal kit purchase and their NQ from February to March 2021. Results: Among the 404 subjects, 37.9% of males and 48.0% of females had experience in purchasing a meal kit (p < 0.001). The highest response indicated that the purchase cost of meal kits was 10,000-20,000 Won at a time, and the frequency of purchase was less than once a month. The convenience of cooking was the main reason for the purchase of meal kits, which were consumed mainly in the evening with family. The satisfaction with the purchase experience of a meal kit was rated 3.6 points for males and 3.7 points for females out of 5 points, and the satisfaction experienced by women was significantly higher than men in terms of freshness of ingredients, packaging design, and adequacy of the quantity of content (p < 0.05). Recognition of the meal kit was rated 3.5 points for males and 3.7 points for females out of 5 points. The purchase intention of the meal kit was rated 3.8 points for those with prior purchase experience, 3.2 points for the non-experienced, 3.3 points for males, and 3.6 points for females out of 5 points each (p < 0.001). The NQ score of dietary behavior in females with experience of meal kit purchases was significantly higher than non-experience (p < 0.05). Conclusions: The dietary behavior of female showed a significant difference by the meal kit purchase experience. It is necessary to understand the consumers' meal kit purchasing behavior to enable the development of various health-oriented meal kit products.

• Korean Journal of Poultry Science
• /
• v.48 no.3
• /
• pp.133-142
• /
• 2021

The purpose of this study was to investigate whether enzyme-hydrolyzed poultry by-product meal (EHPBM) is more effective as a protein source than poultry by-product meal (PBM) and soybean meal (SBM) for broiler chickens. A group of 300 one-day-old broiler chicks was randomly allocated to three treatments with five replicates (20 birds/replicate) for five weeks. The treatments consisted of basal diets containing 1) SBM, 2) PBM, and 3) EHPBM. The EHPBM-fed group (1,853 g±125.60) showed the highest final body weight (P<0.05) when compared to the PBM-fed group (1,723 g±76.81) and SBM-fed group (1,545 g±62.31). The feed conversion ratio of the EHPBM treatment group (1.740±0.104) was significantly higher (P<0.05) than those of the SBM (1.653±0.056) and PBM groups (1.674±0.072). It can be speculated that the increased feed intake in the EHPBM group led to higher body weight gain and FCR. There was no significant effect of treatments on internal organ weight except for the bursa of Fabricius. Blood biochemical characteristic analysis showed that aspartate aminotransferase and alkaline phosphatase levels were higher in the EHPBM and PBM groups (P<0.05), probably due to the strained liver caused by the rapid growth of birds. In conclusion, EHPBM may partly replace conventional dietary protein sources such as soybean meal or poultry by-product meal and can be used to improve the productivity of broilers.