• Korean Journal of Clinical Laboratory Science
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• v.55 no.4
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• pp.253-260
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• 2023

The germanium-68/gallium-68 (⁶⁸Ge/⁶⁸Ga) generator has high spatial utilization and requires little maintenance, making it economical and easy to produce. Thus, the frequency of use of ⁶⁸Ga radiopharmaceuticals is rapidly increasing worldwide. Therefore, this study attempted to develop an automated synthesizer for the routine clinical application of ⁶⁸Ga radiopharmaceuticals. The automated synthesizer was based on a fixed tubing system and the structure was designed after adjusting the position of the parts to reflect the synthesis method. Using various components that can be supplied in Korea, the automated synthesizer was manufactured at a much lower price cost than that of a commercialized automated synthesizer sold by companies. ⁶⁸Ga-DOTA-[Tyr3]-octreotide (⁶⁸Ga-DOTATOC) was synthesized to evaluate the performance of the automated synthesizer. ⁶⁸Ga-DOTATOC could be synthesized with about 65% of non-decay corrected yield, and the synthesized ⁶⁸Ga-DOTATOC met all quality control standards. We have synthesized ⁶⁸Ga-DOTATOC more than 100 times, and only faced a few problems caused by mechanical errors. In this study, we successfully developed a simple automated synthesizer for ⁶⁸Ga radiopharmaceuticals with high reproducibility. As various ⁶⁸Ga radiopharmaceuticals have recently been developed, it is expected that the automated synthesizer developed in this study will be useful for routine clinical use.

• Korean Chemical Engineering Research
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• v.62 no.3
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• pp.246-252
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• 2024

In this study, impurities such as Li and F were removed from waste graphite through citric acid treatment, and changes in structural properties, capacity, and cycle stability of regenerated graphite were observed accordingly. Regenerated graphite pretreated in a nitrogen atmosphere was treated with citric acid, and its structure and characteristics were analyzed through SEM (Scanning Electron Microscope), FT-IR (Fourier Transform Infrared spectroscopy), XRD (X-ray Diffraction), and XPS (X-ray Photoelectron Spectroscopy). Waste graphite that was not treated with acid had a rapid decrease in capacity before 70 cycles, but graphite that had been treated with citric acid showed a capacity of 302.9 mAh g^-1 and a capacity retention rate of 93.1% at 100 cycles. In addition, despite changes in current density in rate performance, samples treated with citric acid showed 340.2 mAh g^-1 performance at 1.0C without change in capacity. As a result, it was confirmed that citric acid treatment not only effectively removed impurities and showed a high capacity retention rate, but also showed stability even at high current densities.

• Journal of Korea Port Economic Association
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• v.39 no.4
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• pp.205-222
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• 2023

This study examines the impact of the changes to the port logistics before and after the COVID-19 pandemic. Specifically, the study focuses on analyzing the changes to Korea's container ports network. Furthermore, this study examines the influence of the ports in the container port network before and after the COVID-19 Pandemic using the network analysis method such as centrality indexes (degree centrality, closeness centrality, and betweenness centrality) to identify changes in the structure and properties of the networks between 2018 and 2021. In this study, We analyzes the changes in the container port networks of Busan, Gwangyang, Incheon, Ulsan, and Pyeongtaek-Dangjin, the five largest ports in Korea. As a result, in case of the Busan port, Singapore port plays an important role, while Busan port plays key roles in ports of Gwangyang, Incheon, and Ulsan. In case of the Gwangyang port, Port Kelang in Malaysia has become increasingly influential as a result of the Malaysian government's policies to overcome the pandemic. In the Incheon port, Japanese ports are playing intermediary roles between their ports and those in the Incheon port network. In the case of Ulsan port, the influence of Korean ports is high, and in the case of Pyeongtaek-Dangjin port, Southeast Asian ports play a role as intermediaries between ports. By analyzing the changes in Korea's port logistics networks, this study can be used as a reference point when responding to uncertainty situations that cause changes to port logistics, such as the COVID-19 pandemic, in the future.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.42 no.2
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• pp.47-55
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• 2024

As climate change issues intensify, the importance of green spaces, a Nature-based Solution (NbS), is being emphasized for urban climate change adaptation. This study analyzes the carbon neutrality effects of the historical landscape forests of Seolleung and Jeongneung, large green spaces in urban areas, using the i-Tree Eco simulation. By doing so, the study underscores the significance of maintenance and management from a climate change adaptation perspective. For the simulation analysis, an inventory was established based on field-measured tree monitoring data of 10,643 trees within the study area, linked with climate data from nearby weather observation stations. The analysis results showed that the trees within the study area annually reduced air pollutants by 5,400 kg, stored 1,260 tons of carbon, and sequestered 98.23 tons of carbon. Additionally, since the study area primarily consists of forest species, it was found that it can secure relatively higher biomass accumulation compared to trees applied to street trees and park green spaces. This emphasizes the need for maintenance and management of historical landscape forests as urban resources that can contribute to national carbon neutrality due to their high forest structure integrity, in addition to their heritage preservation value.

• The Korean Journal of Ecology
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• v.24 no.5
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• pp.289-296
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• 2001

Community structure of the Salix and physico-chemical properties of sediment were studied from July to September, 2000 in Nam-River watershed for the purpose of inquiring niche breadth, niche overlap and the environmental factors affecting the distribution of Salix species. Among eleven Salix species, the dominant species was Salix koreensis, while the rests were such order as S. nipponica, S. gracilistyla and S. glandulosa by the relative abundance based on the basal area. Mean values and the ranges of sediment properties such as pH, conductivity, water content, organic matter, total nitrogen, available phosphorus, clay, silt and sand were 5.3∼6.3, 14∼351 μmho/cm, 0.1∼3.4%, 0.5∼7.3%, 0.01∼0.2%, 0.1∼0.4 mg/100 g, 1.7∼22.0%, 0.2∼40.8%, 39.7∼98.0%, respectively. Altitude and annual mean temperature of each site were 20∼620 m and 9.3∼13.0℃, respectively. Niche breadth was estimated by considering the differences of the soil texture as the differences of state of source. S. glandulosa was the broadest at the level of 0.77, while the rests were such order as S. koreensis, S. nipponica were 0.69, 0.54, respectively. The niche overlap showing the level of interspecific competition was the largest as 0.94 between S. purpurea var. japonica and S. purpurea var multinervis, while S. graciliglans and S. purpurea var. japonica 0.92, S. graciliglans and S. purpurea var. multinervis 0.87, respectively. According to the analysis of the correlation between eleven species of Salix and eleven environmental factors, S. gracilistyla showed the negative correlation with conductivity, water content, total nitrogen, clay, silt and annual mean temperature, and showed the positive correlation with total nitrogen, sand and altitude. S. graciliglans showed the negative correlation with conductivity, water content, organic matter, clay, silt and annual mean temperature, and showed the positive correlation with total nitrogen, sand and altitude. S. nipponica showed the negative correlation with sand and altitude, and showed the positive correlation with water content, total nitrogen, clay, silt and annual mean temperature. S. nipponica showed the opposite results of S. gracilistyla. Soil texture, total nitrogen, water content, altitude and annual mean temperature were affecting the distribution of Salix species in Nam-River watershed.

• Journal of the Korean Geographical Society
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• v.40 no.1 s.106
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• pp.126-152
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• 2005

In recent years, there are some confusions related to the definition and existence of mountain ranges, which have been described in current geography text books. We contend that these confusions came from the lack of understanding on the geomorphological processes that form the mountain system in Korea. This research attempts to clarify the definition of mountain ranges and offer geological and geomorphological explanations about the formation of them. Based on the analyses of the social and cultural causes underlying the recent debates on the existence of mountain ranges, we tried to identify the relationships among the definition of mountain ranges, geological structure of Korea, and the forming processes of mountain ranges. The current and past mountain range maps were compared with geological structures, geological maps, surface curvature, and hill shade maps. The latter two maps were derived from a Digital Elevation Model of the Korean Peninsular. The results show that we are able to prove the existence of most mountain ranges, which provides a useful framework to understand the geological evolution of Korean peninsular and formation of mountainous landscape of Korea. In terms of their morphological continuity and genesis, however, we identified five different categories of mountain ranges: 1) Uplift mountain ranges(Hamkyeong Sanmaek, Nangrim Sanmaek, Taebaek Sanmaek), which were formed by the uplift processes of the Korean Peninsular during the Tertiary; 2) Falut mountain ranges(Macheonryeong Sanmaek, Sobaek Sanmaek, Buksubaek Sanmaek), whirh were directly related to the uplift processes of the Korean Peninsular during the Tertiary; 3) Trust mountain ranges(Jekyouryeong Sanmaek, Kwangju Sanmaek, Charyeong Sanmaek, Noryeong Sanmaek), which were formed by the intrusion of granite and consequent orogenic processes during the Mesozoic era; 4) Drainage divide type mountain ranges, which were formed by the erosion processes after the uplift of Korean Peninsular; 5) Cross-drainage basin type mountain ranges (Kangnam Sanmaek, Eunjin Sanmaek, Myelak sanmaek), which were also formed by the erosion processes, but the mountain ranges cross several drainage basins as connecting mountains laterally We believe that the current social confusions related to the existence of mountain ranges has partly been caused by the vague definition of mountain ranges and the diversity of the forming processes. In order to overcome theses confusions, it is necessary to characterize the types of them according the genesis, the purpose of usages and also the scale of maps which will explains the mountain systems. It is also necessary to provide appropriate educational materials to increase the general public's awareness and understanding of geomorphological processes.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.5 s.108
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• pp.461-475
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• 2006

In this paper, it is described about the tri-band mobile antenna system design to provide broadband multimedia and direct broadcasting services using goo-stationary Koreasat 3, simultaneously operated in Ka/K/Ku band. The radiating part of the antenna system with a fan beam characteristic in the elevation plane is composed of the quasi-offset dual shaped reflector and the tri-band feeder. The tri-band feeder is also composed of the Ka/K dual band feeder with the protruding dielectric rod, the circular polarizer, the ortho-mode transducer and the circular-polarized Ku band feed array. Especially, the Ka/K dual band circular polarizer was realized firstly using the comb-type structure. For fast satellite-tracking on the movement, the Ku band feed array has the structure of the $2{\times}2$ active phased array which can make electrical beams. And, the circular-polarized characteristic in the feed array was improved by $90^{\circ}$ rotating arrangement of four radiating elements polarized circularly by a $90^{\circ}$ hybrid coupler, respectively. Four beam forming channels to make electrical beams at Ku band are divided into the main beam channel and the tracking beam channel in the output, and noise temperature characteristics of each channel were analyzed on the basis of the contributions of internal sub_units. From the fabricated antenna system, the output power at $P_{1dBc}$ of Ka_Tx channel was measured more than 34.1 dBm and the measured noise figures of K/Ku_Rx channels were less than 2.4 dB and 1.5 dB, respectively, over the operating band. The radiation patterns with co- and cross-polarization in the tri-band were measured using a near-field measurement in the anechoic chamber. Especially, Ku radiation patterns were measured after correcting each initial phase of active channels with partial radiation patterns obtained from the independent excitation of each channel. The antenna gains measured in Ka/K/Ku band of the antenna system were more than 39.6 dBi, 37.5 dBi, 29.6 dBi, respectively. And, the antenna system showed good system performances such as Ka_Tx EIRP more than 43.7 dBW and K/Ku_Rx G/T more than 13.2 dB/K and 7.12 dB/K, respectively.

• Journal of Agricultural Extension & Community Development
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• v.21 no.4
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• pp.1125-1147
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• 2014

This study was conducted to develop the health evaluation indicator of pond wetland in order to enhance the quality of eco-experience in rural area. The methods for development of evaluation indicator were consisted of 3 stages; 1st, the precedent assessment protocol was applied to 10 pond wetlands in farm villages, and eco-experience expert survey was conducted to selection the evaluation item and criteria at 2nd and 3rd stages. In the results of applying the precedent assessment protocol, we found out two problems; 1) the evaluation result of value determination and conservation value were too simple, and 2) the score by evaluation items were nearly the same, because evaluation criteria in not precisely for application in rural area. These results were reflected to expert survey. According to the 1st survey results, they suggested that 4 items should be maintained, and 3 items should be deleted, and 2 items should be modified among a total of 9 times. Therefore, it was modified into the evaluation protocol having a total of 8 items. According to the 2nd survey results, the selected evaluation items were generally proper. With regard to items for assessing the health condition of pond wetland, we selected a total of 8 items; (1) Connectivity to forest, (2) Connectivity between water body and wetland connection, (3) Number of Vegetation, (4) Surround land use, (5) Interspersion of Vegetation, (6) Crossing Structure, (7) Wetland size, and (8) Outlet structure. In addition, it was suggested that accessibility, visibility, and trash were need for utilization of pond wetland as a place for eco-experience. It is expected that the selected evaluation indicator can help to utilize the pond wetland as an eco-experience space in rural area, and maintain the pond wetland as a space for conservation of biodiversity.

• Korean Journal of Ecology and Environment
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• v.47 no.3
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• pp.176-185
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• 2014

There are no population ecological research on the natural monument (No. 191) Jeju Cymbidium kanran in South Korea. In this study, we analyzed the population structure and fine-scale habitat affinity of C. kanran in Sanghyo-dong, Jejudo Island from Oct. 2013 to Feb. 2014. We observed total of 1,237 individuals (4,341 pseudobulbs) of C. kanran (989.6 population $ha^{-1}$) within (1.25 ha) and only 17 (1.4%) individuals were inflorescent. In 60.9% of the entire populations, disease symptoms such as spots and blight leaves were observed. C. kanran populaton exhibited reverse-J shaped size distribution based on leaf area classes as individual size parameter. The three size related attributes of C. kanran (no. of pseudobulb $r_s$=-0.159, no. of leaves $r_s$=-0.148 and leaf arera $r_s$=-0.114) and soil temperature revealed a negative relationship (p<0.0001). Most of C. kanran (95.4%) were grown under Castamopsis cuspidata and spatially, C. kanran were strongly clumped at all distances. Population characteristics of C. kanran in the study area were likely originated from species habitat affinity and successional environment. Through this study, base line data for C. kanran's habitat monitoring was established and conservation measures based on population characteristics were discussed.

• Sijohaknonchong
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• v.44
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• pp.29-56
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• 2016

The purpose of this article is to shed light on the position and the importance of sijo (Korean traditional poetic form of Three-Line Stanzas) of the Korean poet Park Jae-sam among Korean sijo writers. Even though Park Jae-sam started his career as a poet writing two sijos and a poem, he began to write more poems than sijos later on. Anyway his interest in sijo writing has continued and he has served as a judge of sijo writing contests ever since. Especially in 1985, he published a collection of sijo. And each sijo writing in this collection are composed of three-line stanzas and each stanza of three lines. And each line has a rhythmic sound with a formal word formation. This article reveals that Park Jae-sam has pursued a happy unity of form and content in his sijo writings from the collection and that he has tried his hardest to realize this goal. This article notes that for this goal he puts stress on some methods of creating poetic images and the process of creating new ideas, the unity of Koreans's unique emotion of han(恨) and a sense of eternity, transcendence through ambivalent emotions, and the structure of statement mainly made of juxtaposed metaphors. And this articles also notes that as a most sincere lyric poet in the history of sijo he is much distinguished from other Korean poets in that he depicts mainly Koreans's unique emotions and their characteristics.