• 보존과학연구
• /
• s.27
• /
• pp.165-180
• /
• 2006

The research was conducted to understand type of iron used by those who lived at dwelling site of Yangsoo-ri in between the first century B.C. and the first century A.D. to make steel products and their technique such as steel making process and heat treatment, based on micro structure information obtained through microscopic metallographic structure analysis with SEM-EDS of six steel productsexhumed at the site. Key findings are summarized as below. In the sense that Si-Ca-Al style and less than 0.5% of Ti were found in the non-metallic inclusion, the material used for forged iron ware was magnetite resolved in that. It is, however, unclear whether magnetite was resolved at high temperature or at low temperature. Microscopic structure analysis revealed that forged steel products were made through repeated hot working, the technique of molding by hitting after heating in the process of resolving and molding iron. As a result, the iron used here for the products was not the iron ore which was produced through resolution from discarded cast iron axe, ingot iron. It is probable that to make those steel products, disposed-of cast iron was reused after being molded by decarburizing. Although a few of relics were analyzed for the research, they were of critical importance in defining the process of ironware production from the first century B.C. and the first century A.D. at the Yangsoo-ri region. Judging from the iron from A-19 dwellingsite, it is possible to conclude that the iron was manufactured from cast iron decarburized and yet more research has to be done into relics yetto be exhumed in order to ascertain the finding. All of these findings are believed to play a critical role in further studies to define the steel-manufacturing technique used on the central Korean peninsular in the ancient times.

• The Korean Journal of Ecology
• /
• v.5 no.4
• /
• pp.204-210
• /
• 1982

Comparative study of the biomass productioin and the cyclings of nitrogen, phosphorus and potassium was carried out on the east and the northwest facing slope in the montane grassland of Mt. Soback. The maximum productin during the growing season in the east and the northwest slope were 1, 150g/m2.yr, and 755g/m2.yr. in the August, respectively. The positive correlation was appearent between biomass production and A-layer depth of the soil and the correlation coefficient (r=.964) was very significant at 1% level. In the above ground materials, the nutrients contents were high at the early of the growing season but decreased gradually. In roots, however, there are no significant trend throughout the growing season. Total amounts of minerals uptaken by plants during the growing season in the east and the northwest site were 18.20 and 10.66g/m2.yr for N, 0.06 and 0.03g/m2.yr for P, 0.23 and 0.11g/m2.yr for K, respectively. the minerals returned to the soil by litter decomposition and roots decay in the east and the northwest site were 16.19 and 9.62g/m2.yr for N, 0.046 and 0.021g/m2.yr for P, 0.211 and 0.099g/m2.yr for K, respectively. The turnover the rate (absorbed/returned) of the nutrients in the east and the northwest site were 1.13 and 1.14 for N, 1.30 and 1.43 for P, 1.09 and 1.11 for K, and the absorption rates of minerals were 0.39 and 0.29% for N, 3.16 and 1.88% for P, 0.91 and 0.57% for K, respectively.

• Animal Bioscience
• /
• v.34 no.6
• /
• pp.985-992
• /
• 2021

Objective: Artificial insemination plays an important role in genetic improvement in the goat farming system. The aim of this study was to investigate the effect of cervical application of hyaluronan (HA) on the fertility in goats after cervical artificial insemination using frozen-thawed (F-T) semen. Methods: After oestrous synchronisation with progesterone sponges and pregnant mare serum gonadotropin injection, both nulli- and multi-parous goats, were randomly allocated to 2 groups, and were inseminated with 0.25 mL of F-T semen (150×106 spermatozoa) twice at 52 h and 56 h after sponge removal. Prior to the insemination, goats in Group 1 only were given topical cervical HA application at 48 h after sponge removal. Site of insemination was recorded as os-cervix or intra-cervix or intra-uterus. Pregnancy was tested ultrasonographically 42 days after insemination. The data on pregnancy rates and percentage of animals according to the site of semen deposition were compared by Chi-square analysis. Results: The overall pregnancy rate was significantly (p<0.004) higher in goats with prior application to the cervix with HA (63.3%) than without (36.0%). Same pattern was observed in the pregnancy rates of nulli- and multi-parous goats in both the groups. Percentage of nulliparous goats according to the site of insemination in the HA group did not differ between first and the second insemination. However, in multiparous goats the percentage of animals inseminated intra-cervically was significantly increased (p≤0.05) between the first and the second inseminations. Conclusion: The results suggest that significantly higher fertility rate in the "HA goats" compared to the "without HA" group was because of deeper insemination facilitated by topical cervical application of HA. The deeper insemination into the cervical canal increase the rate of fertilisation when the cervical artificial insemination is performed.

• Korean Journal of Construction Engineering and Management
• /
• v.20 no.4
• /
• pp.114-125
• /
• 2019

Off-Site Construction (OSC) is a new construction method based on factory production. OSC (Off-Site Construction) is a new construction method based on factory production. Researches such as OSC-related design and production standardization, transport methods are actively conducted in the U.S., UK and other parts of the world as this new method has an edge over existing methods in terms of productivity, economy and quality. As the emergence of this new area requires reasonable management, an analysis of the scope of construction project management is required accordingly. Therefore, this research analyzed the study trends and relationships at the CM/PM range's "Operation level" to identify areas of study, relationship between studies and deficiencies in current research. This study carried out a comprehensive literature review of the OSC (CM/PM) research by analyzing 94 papers in Operation level as of September 3, 2018, and the analysis results are as follows. (1) Working stage level researches have been increasing rapidly since 2006. (2) Non-volumetric type is contributing most significantly at work stage level. In the building sector, it has been identified that problems such as residential: living, quality issues, non-residential: economic difficulties, factory: productivity problems have been addressed. (4) The Non-volumetric pre-assembly type dealt with the economic feasibility of residential and non-residential buildings, whereas the modular type was studied in regards to assembly quality. (5) From 2006, project management areas (e.g., quality, human resources, risks) have been expanded. It is expected that this research will help find new areas of research for OSC. If the analysis is carried out to the level of the industrial, corporate and project phases in the future, it is deemed that the overall research flow and area of the OSC industry can be identified.

• Journal of Microbiology and Biotechnology
• /
• v.4 no.2
• /
• pp.126-133
• /
• 1994

A Pseudomonas putida strain able to accumulate high amount of polyesters of medium-chain-length 3-hydroxyalkanoic acids ($PHA_{MCL)$) was isolated from soil in a landfill site using an enrichment technique. Culture condition of the isolated strain for polyester production in a one-step culture was optimized in a mineral-salts medium against pH and concentrations of ammonium sulfate, carbon source(e.g., octanoate), and phosphate. The optimal values for maximal cell growth and PHA accumulation were: pH; 7$\sim$8, $(NH_4)_2SO_4$; 8 mM, octanoate; 40 mM. The optimum temperature was in the range of $20\sim30^{\circ}C$, which was rather broader than in other bacteria. Cell growth was strongly inhibited by the phosphate limitation to less than 1 mM. An increase of phosphate concentration above 1 mM showed little effect on cell growth and polyester accumulation. When the strain was grown on octanoate under this optimized condition it produced 3.4 g dry biomass per liter and yielded 1.7 g PHA per liter amounting to 53 wt% of dry cells. The monomer units composing the polyester synthesized from octanoate were 3-hydroxyoctanoate (3HO), 3-hydroxycaproate (3HC), and 3-hydroxybutyrate (3HB) (85:13:2, mole ratio). Other low linear $C_3\simC_{10}$ monocarboxylic acids were also tested for polyester production.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.64 no.4
• /
• pp.337-342
• /
• 2015

The company of 4 core materials that are needed for photovoltaic generation is located in area around this university in Gunsan, Saemangeum. And also, it was almost completed the value chain about the production of Polysilicon, Ingot, Wafer, modules and the design, construction of generation system. The industry-academy-government has understood that because of the relative companies' production and investment, it leads to a supply and demand of manpower and thus will have field centered manpower education. This program will help the problem of lack of manpower in relative companies by establishing competitive major agreement like vocational education system. Also, the university and the participating company in joint have pushed ahead field business education to make the least of industrial-education's mismatch, the training of professional manpower connected with related industries to make the universities chemical characteristics, companies securing excellent manpower and contributed to the revitalization of the regional economy. In this paper, are aware that photovoltaic industry is a future strategic industry for the country, so we will train the immediately site adapting manpower for the area of photovoltaic material and system as our goal. This is shown results of education operation for 4 years.

• Journal of Ecology and Environment
• /
• v.34 no.3
• /
• pp.295-305
• /
• 2011

Many studies have suggested the positive effects of grazing by large herbivorous mammals on seed dispersal, but little is known about how herbivores could affect the fate of ingested seeds. This study examined the effects of seed ingestion by sika deer (Cervus nippon) on seed fate in a temperate grassland established in an urban park long resided by high densities of sika deer. I compared species composition and seasonal traits of seed abundance and maturity in the grassland community with those in deer fecal pellets. In total, 27 herbaceous species were observed, including the predominant Zoysia japonica. Seed phenology and production differed among the three dominant species (Z. japonica, Digitaria violascens, and Hydrocotyle maritima). Pellets contained at least 26 species of herbaceous seeds, and their abundance differed among species. Of the 26 species, 15 were observed in the vegetation at the study site. The peak of seed abundance in pellets for the dominant species appeared 1 month after the peak of inflorescence production (but most of the inflorescences were immature and susceptible to digestion) and consequently corresponded to the peak of mature inflorescence. Because sika deer are likely to ingest seeds at any maturity stage in the grassland and immature seeds are less hardened, ingested immature seeds can suffer great losses. The results suggested that the survival of germable seeds with great losses of immature seeds may be a factor determining which plant species can be successfully dispersed by herbivores.

• Journal of the Korean housing association
• /
• v.27 no.3
• /
• pp.11-22
• /
• 2016

In Germany, during the modern architectural movements diverse experiments for the propagation of modern housing solutions were conducted that succeeded to the spirit of Bauhaus. Therefore, the study traced how Walter Gropius adopted the trends of architectural style and aesthetic, the concept of production, the concept for new typology of housing, and issues in urban architecture. According to the results, processes to the 'sachlich' style could be seen in the cases of early and latter works of detached houses and further aesthetic changes of later works. Second, Gropius expanded his design field from detached houses to multiple dwelling and it was accompanied by typological transformation of buildings considering the industrialization and production of housing. Third, in the cases of multiple dwelling, it could be identified that site planning of housing complexes and building arrangement reflected a shift from traditional urban pattern to new alternatives suitable for mass housing supply. Thus, changes in the genealogy and propensity of German residential designs were partly summed up and their implications on modern housing architecture were discussed.

• Journal of the Korean Solar Energy Society
• /
• v.29 no.2
• /
• pp.22-30
• /
• 2009

In order to clarify predictive accuracy for the wind resource predicted by running WindPRO(Ver. 2.5) which is software for wind farm design developed by EMD from Denmark, an investigation was carried out at the northeast region of Jeju island. The Hangwon, Susan and Hoichun sites of Jeju island were selected for this study. The measurement period of wind at the sites was for one year. As a result, when the sites had different energy roses, though the two Wind Statistics made by STATGEN module were used for the prediction, it was difficult to exactly predict the energy rose at a given site. On the other hand, when the two Wind Statistics were used to predict the average wind speed, the wind power density and the annual energy production, the relative error was under ${\pm}20%$ which improved more than that when using only one Wind Statistics.

• Journal of Korean Library and Information Science Society
• /
• v.50 no.2
• /
• pp.339-359
• /
• 2019

The purpose of this study is to clarify the case and process of the application of the sign system in order to enable the user to reach the target site more efficiently in the library. For this purpose, a new sign system was applied to the S University library through procedures such as library structure, sign status, user observation, cyan production and preference survey. Detailed production process and user's reaction were identified. Based on this we suggested improvements to the library stacks signage system.