• Korean Journal of Heritage: History & Science
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• v.46 no.1
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• pp.208-227
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• 2013

Twenty-seven bronze bowls excavated from the Goryo burial complex at Deobu-gol were examined for their microstructure and chemical composition to characterize the bronze technology practiced by commoners at the time. Results showed that the objects examined can be classified into four groups: 1) objects forged out of Cu-near 22%Sn alloys and then quenched; 2) objects cast from Cu-below 10% Sn alloys containing lead; 3) objects cast from Cu-10%~20% Sn alloys containing lead and then quenched; 4) objects forged out of Cu-10~20% Sn alloys containing lead and then quenched. This study revealed that the fabrication technique as determined by alloy compositions plays an important role in bronze technology. The use of lead was clearly associated with the selection of quenching temperatures, the character of inclusions and the color characteristics of bronze surfaces. It was found that the objects containing lead were quenched at temperatures of $520^{\circ}{\sim}586^{\circ}C$ while those without lead were quenched at the range of $586^{\circ}{\sim}799^{\circ}C$. The presence of selenium in impurity inclusions was detected only in alloys containing lead, suggesting that the raw materials, Cu and Sn, used in making the lead-free alloys for the first group were carefully selected from those smelted using ores without lead contamination. Furthermore, the addition of lead was found to have significant effects on the color characteristics of the surface of bronze alloys when they are subjected to corrosion during interment. In leaded alloys, corrosion turns the surface light green or dark green while in unleaded alloys, corrosion turns the surface dark brown or black. It was found that in fabrication, the wall thickness of the bronze bowls varies depending on the application of quenching; most of the quenched objects have walls 1mm thick or below while those without quenching have walls 1mm thick or above. Fabrication techniques in bronze making usually reflect social environments of a community. It is likely that in the late Goryo period, experiencing lack of skilled bronze workers, the increased demand for bronze was met in two ways; by the use of chief lead instead of expensive tin and by the use of casting suitable for mass production. The above results show that the Goryo bronze workers tried to overcome such a resource-limited environment through technological innovations as apparent in the use of varying fabrication techniques for different alloys. Recently, numerous bronze objects are excavated and available for investigation. This study shows that with the use of proper analytical techniques they can serve as a valuable source of information required for the characterization of the associated technology as well as the social environment leading to the establishment of such technology.

• Korean Journal of Poultry Science
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• v.46 no.2
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• pp.105-115
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• 2019

In this study, viability, growth performance and egg production performance were investigated to determine the productive characteristics of 12 Korean domestic chicken varieties which have been collected and conserved for over 25 years in National Institute of Animal Science, Rural Development Administration, Korea. The 1,134 hens were tested and their production traits including survival rate, body weight, age at first egg laying, hen-day and hen-housed egg production, egg weight, and egg quality were measured. Survival rate was the highest in Korean Rhode-D and Korean Native Chicken (KNC) White and the lowest in Korean Cornish Brown (92.2% and 54.3%, respectively). Body weights from 4 to 50 wks were consistently high in the order of Korean Cornish, Korean Rhode, KNC, Korean Ogye, and Korean Leghorn breeds. There was no significant difference in weight between varieties within a breed. Age at first egg laying was the shortest in Korean Leghorn, while it was the longest in Korean Cornish. The hen-day egg production from $1^{st}$ egg to 57 wks was the highest in Korean Leghorn-K, and the lowest in Korean Cornish Brown. Egg weight was the heaviest in Korean Leghorn-F and the lightest in KNC White. The Haugh unit was the highest in Korean Rhode-C and the lowest in Korean Ogye. Taken together, these results suggest that it is desirable that the Korean Cornish variety is improved as the Korean meat breed because of its excellent growth ability, the Korean Leghorn variety is improved as the Korean layer breed because of its good laying performance, and the Korean Rhode and KNC varieties are improved as strong viable breeds because of their good survival rate.

• Korean Journal of Environment and Ecology
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• v.35 no.1
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• pp.68-80
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• 2021

This study aimed to provide basic data such as the structure of the Carpinus turczaninowii community and characteristics of the habitat environment for ex situ conservation by analyzing the plant community structure of Carpinus turczaninowii, an island plant resource. For the community structure analysis, this study established 29 plots, sized 100㎡ each, in Seokmo, Yeongjong, Yeongheung, and Daebu islands. TWINSPAN was used for the classification of communities. The classification identified six communities. Group I was the C. turczaninowii-Quercus serrata community, group II was the C. turczaninowii-Pinus densiflora community, group III was the C. turczaninowii-Quercus mongolica community, group IV was the C. turczaninowii-Sorbus alnifolia community, group V was the C. turczaninowii typical community, and group VI was the C. turczaninowii-Quercus variabilis community. The species diversity was 0.90008~1.12868, the dominance was 0.17536~0.25665, and the similarity index was 17.1429~38.2979%. The result of correlation analysis of 7 environmental factors for 6 communities by RDA ordination showed a positive correlation between the crown density and litter layer and a negative correlation between the bare rock, soil hardness, and altitude on the 1st axis. On the 2nd axis, the bare rock and crown density showed a positive correlation, and the slope showed a negative correlation. In the C. turczaninowii-Quercus serrata community (I), the crown density and the litter layer were the environmental factors affecting the vegetation distribution. In the C. turczaninowii-Pinus densiflora (II) and C. turczaninowii-Quercus mongolica (III) communities, the slope was the factor affecting vegetation distribution. In the C. turczaninowii-Sorbus alnifolia (IV), C. turczaninowii typical (V), and C. turczaninowii-Quercus variabilis (VI) communities, the bare rock, altitude, and soil hardness were the factors affecting vegetation distribution.

• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.444-451
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• 2022

Recently, long-term cultivation is becoming more common with the increase in tomato hydroponics. In hydroponics, it is very important to supply an appropriate nutrient solution considering the nutrient and moisture requirements of crops, in terms of productivity, resource use, and environmental conservation. Since seasonal environmental changes appear severely in long-term cultivation, it is so critical to manage irrigation control considering these changes. Therefore, this study was carried out to investigate the effect of irrigation volume on growth and yield in tomato long-term cultivation using coir substrate. The irrigation volume was adjusted at 4 levels (high, medium high, medium low and low) by different irrigation frequency. Irrigation scheduling (frequency) was controlled based on solar radiation which measured by radiation sensor installed outside the greenhouse and performed whenever accumulated solar radiation energy reached set value. Set value of integrated solar radiation was changed by the growing season. The results revealed that the higher irrigation volume caused the higher drainage rate, which could prevent the EC of drainage from rising excessively. As the cultivation period elapsed, the EC of the drainage increased. And the lower irrigation volume supplied, the more the increase in EC of the drainage. Plant length was shorter in the low irrigation volume treatment compared to the other treatments. But irrigation volume did not affect the number of nodes and fruit clusters. The number of fruit settings was not significantly affected by the irrigation volume in general, but high irrigation volume significantly decreased fruit setting and yield of the 12-15th cluster developed during low temperature period. Blossom-end rot occurred early with a high incidence rate in the low irrigation volume treatment group. The highest weight fruits was obtained from the high irrigation treatment group, while the medium high treatment group had the highest total yield. As a result of the experiment, it could be confirmed the effect of irrigation amount on the nutrient and moisture stabilization in the root zone and yield, in addition to the importance of proper irrigation control when cultivating tomato plants hydroponically using coir substrate. Therefore, it is necessary to continue the research on this topic, as it is judged that the precise irrigation control algorithm based on root zone-information applied to the integrated environmental control system, will contribute to the improvement of crop productivity as well as the development of hydroponics control techniques.

• Journal of the Korean Institute of Landscape Architecture
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• v.50 no.1
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• pp.1-19
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• 2022

The Geumgang Pine (Pinus densiflora) Forest in Sogwang-ri, Uljin has traditionally been a pine tree protection area (prohibited forest) for timber production purposes, and is now designated and managed as a protected area for forest genetic resource conservation by the Korea Forest Service. This study, we analyzed topographical characteristics, existing vegetation, tree age, and plant community structure, and proposed a sustainable management method for the Geumgang Pine (Pinus densiflora) Forest in Sogwang-ri, Uljin for timber havesting purposes. The topographical characteristics of the target area were 36.7% ridges and 38.7% valleys; the ratio of ridges to valleys was similar, and the slopes formed 24.7% of the total area. The types of pine forest communities are divided into six types based on the progress of pine forest renewal, the competition with other species such as deciduous broadleaf trees, and the formation of layered structures. It has been confirmed that the age of the large-diameter pine trees (40~60cm in diameter) is approximately 60~70 years, which is relatively low. As a result of the analysis of the relative importance percentage and layered structure, differences depended on the progress of the pine forest renewal project, and not only the maintenance of the pine forest, but also the creation of a secondary growth forest, the density adjustment of pine trees, and the active management of competitive trees. The average basal area by the community was 12,642.1~25,424.4cm² for the tree layer and 1.8~1,956.5cm² for the low tree layer based on a quadrat of 400m². The difference in the basal area appeared to depend on the size and number of trees forming the tree layer and the degree of pine forest renewal (the degree of time elapsed after thinning pine trees). The average number of species that appeared in each community was 8.7-20.3; there were many species located in valleys, and the type competes with deciduous broadleaf trees due to the lack of management. The diversity of species ranged from 0.6915-1.0942, and was evaluated as low compared to pine communities in central temperate zones. In this paper, we determined the management goals of Geumgang Pine (Pinus densiflora) Forest in Sogwang-ri, Uljin to produce timber with high economic value, and suggested efficient vegetation management for continuous afforestation, the establishment of a timber production system, and improvement of wood production as a management direction.

• Korean Journal of Ichthyology
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• v.35 no.4
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• pp.263-269
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• 2023

This study aims to contribute to the research on resource recovery for the rapidly declining population of Liparis tanakae by observing the larval development process and the morphology of juveniles based on their growth. Natural spawning eggs collected in Yeosu were used for observing the process of egg development and larval morphology. The water temperature during the rearing process was maintained at 12.3~13.5℃ (average 12.7℃). The fertilized eggs had an egg diameter ranging from 1.57 to 1.79 mm (average 1.71 mm) and were spherical and adhesive. Within 4 hours 35 minutes after fertilization, they reached the two-cell stage, and after 74 hours 10 minutes, the formation of the yolk sac began. At 106 hours post-fertilization, a caudal fin appeared at the tail tip. Hatching began at 526 hours, and the larvae developed with the yolk sac positioned just behind the eyes. The newly hatched larvae had both the mouth and anus open. Melanophores appeared inside the lower jaw and around the tail on the third day after hatching. By the 16th day after hatching, most of the yolk was absorbed, and melanophores were visible in the head region. Finally, on the 63rd day after hatching, the head region significantly developed, and the body shape and mouth were similar to those of an adult fish, signifying the transition to the juvenile stage. This study will serve as valuable data for aquaculture techniques related to the conservation and restoration of fish species based on the hatching and juvenile morphology of Liparis tanakae.

• Korean Journal of Environment and Ecology
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• v.38 no.4
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• pp.375-387
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• 2024

This study investigated the ecological characteristics of Fraxinus chiisanensis Nakai, one of the endemic and rare plant species in Korea, based on its distribution status, characteristics of the growth environment, and species composition. A vegetation survey that analyzed the correlation between species distribution patterns and environmental variables, along with the traits of the emergent plant species, was performed according to the explanation of environmental growth conditions and phytosociological method for the location where F. chiisanensis is found. A total of 19 dominant locations and 9 non-dominant locations of F. chiisanensis were observed in 28 study sites in 12 regions, and a total of 155 taxa were observed. According to the vegetation climate of Korea, the growth environment of the study site where F. chiisanensis is located is characterized as cold and is primarily situated within the northern temperate deciduous broadleaf forest zone. The average elevation was 859m above sea level, with an average rock exposure of 60.4%, soil exposure of 24.7%, and an average slope of 18.7°. The taxa belonging to the top P-NCD(Percentage of Net Contribution Degree) among the emergent species were mostly designated as the taxa emerging in valley vegetation. The correlation analysis of environmental variables revealed that altitude had the strongest correlation, with rock exposure showing the second highest correlation. The ongoing dynamics of the F. chiisanensis forest are anticipated to persist due to the high P-NCD values exhibited by the F. chiisanensis within the shrub and herbaceous layers among the taxa associated with tree species. Most F. chiisanensis habitats are currently situated within protected regions such as national parks, provincial parks, and county parks, where there are relatively minimal human-induced disturbances. However, there is potential for damage in areas not designated as protected, such as forest tending operation sites or new hiking trails. Concerns about declining habitat quality have prompted suggestions for management strategies such as establishing Forest Genetic Resource Reserves in these locations. In addition, follow-up and further research should be conducted to identify possible sites for distribution and establish candidate conservation areas based on various environmental conditions of F. chiisanensis.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.5
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• pp.321-327
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• 2006

In Korea, there is a growing competitive for water resources between industrial, domestic and agricultural consumer, and the environment as many other OECD countries. The demand on water use is also affecting aquatic ecosystems particularly where withdrawals are in excess of minimum environmental needs for rivers, lakes and wetland habits. OECD developed three indicators related to water use by the agriculture in above contexts : the first is a water use intensity indicator, which is expressed as the quantity or share of agricultural water use in total national water utilization; the second is a water stress indicator, which is expressed as the proportion of rivers (in length) subject to diversion or regulation for irrigation without reserving a minimum of limiting reference flow; and the third is a water use efficiency indicator designated as the technical and the economic efficiency. These indicators have different meanings in the aspect of water resource conservation and sustainable water use. So, it will be more significant that the indicators should reflect the intrinsic meanings of them. The problem is that the aspect of an overall water flow in the agro-ecosystem and recycling of water use not considered in the assessment of agricultural water use needed for calculation of these water use indicators. Namely, regional or meteorological characteristics and site-specific farming practices were not considered in the calculation of these indicators. In this paper, we tried to calculate water use indicators suggested in OECD and to modify some other indicators considering our situation because water use pattern and water cycling in Korea where paddy rice farming is dominant in the monsoon region are quite different from those of semi-arid regions. In the calculation of water use intensity, we excluded the amount of water restored through the ground from the total agricultural water use because a large amount of water supplied to the farm was discharged into the stream or the ground water. The resultant water use intensity was 22.9% in 2001. As for water stress indicator, Korea has not defined nor monitored reference levels of minimum flow rate for rivers subject to diversion of water for irrigation. So, we calculated the water stress indicator in a different way from OECD method. The water stress indicator was calculated using data on the degree of water storage in agricultural water reservoirs because 87% of water for irrigation was taken from the agricultural water reservoirs. Water use technical efficiency was calculated as the reverse of the ratio of irrigation water to a standard water requirement of the paddy rice. The efficiency in 2001 was better than in 1990 and 1998. As for the economic efficiency for water use, we think that there are a lot of things to be taken into considerations to make a useful indicator to reflect socio-economic values of agricultural products resulted from the water use. Conclusively, site-specific, regional or meteorogical characteristics as in Korea were not considered in the calculation of water use indicators by methods suggested in OECD(Volume 3, 2001). So, it is needed to develop a new indicators for the indicators to be more widely applicable in the world.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.41 no.2
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• pp.35-45
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• 2023

First, The spatial distribution characteristics of old big trees were analyzed using ArcGIS figures by combining basic information such as species and ages of old big trees in Handan City, which were compiled by the local bureau of landscaping. The types of species, distribution by ages of trees, ownership status, growth status, and diversity status were comprehensively analyzed. Statistically, Styphnolobium, Acacia, Gleditsia, and Albizia of Fabaceae accounted for the majority, of which Sophora japonica accounted for the highest proportion. Sophora japonica is widely and intensively distributed to each prefecture and district in Handan city. According to the age and distribution, the old big trees over 1000 years old were mainly Sophora japonica, Zelkova serrata, Juniperus chinensis, Morus australis Koidz., Dalbergia hupeana Hance, Ceratonia siliqua L., and Pistacia chinensis, and Platycladus orientalis. Second, as found in each type of old big tree status, various types of old big tree status were investigated, the protection management system, protection management process, and protection management benefits were studied, and the protection of old big tree was closely related to the growth environment. Currently, the main driving force behind the protection of old big trees is the worship of old big trees. By depositing its sacredness to the old big tree and sublimating the natural character that nature gave to the old big tree into a guiding consciousness of social activities, nature's "beauty" and personality's "goodness" are well combined. The protection state of the old big tree is closely related to the degree of interaction with the surrounding environment and the participation of various cultures and subjects. In the process of continuously interacting with the surrounding environment during the long-term growth of old big trees, it seems that a natural sanctuary was formed around old big trees in the process of voluntarily establishing a "natural-cultural-scape" system involving bottom-up and top-down cross-regions, multicultural and multi-subjects. Third, China focused on protecting and recovering old big trees, but the protection management system is poor due to a lack of comprehensive consideration of historical and cultural values, plant diversity significance, and social values of old big trees in the management process. Three indicators of space's regional characteristics, property and protection characteristics, and value characteristics can be found in the evaluation of the natural characteristics of old giant trees, which are highly valuable in terms of traditional consciousness management, resource protection practice, faith system construction, and realization of life community values. A systematic management system should be supported as to whether they can be protected and developed for a long time. Fourth, as the perception of protected areas is not yet mature in China, "natural sanctuary" should be treated as an important research content in the process of establishing a nature reserve system. The form of natural sanctuary management, which focuses on bottom-up community participation, is a strong supplement to the current type of top-down nature reserve management in China. Based on this, the protection of old giant trees should be included in the form of a nature reserve called a natural monument in the nature reserve system. In addition, residents of the area around the nature reserve should be one of the main agents of biodiversity conservation.