• Journal of the Korea Organic Resources Recycling Association
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• v.19 no.1
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• pp.123-130
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• 2011

Objectives of this study were to compare the environmental effects of digestates produced in bioenergy village on the rice paddy field for recycling. Digestates were applied to the soils and the soil properties and the crop responses were analyzed according to the standard methods of soil evaluation. Plant height and the number of tiller showed similar results in both the conventional and digestate treated field, and the yield of rough rice was higher in the field treated with digestates than that with chemical fertilizer. The amounts of nitrogen absorbed in straw and grain were larger in the digestates-treated field than chemical fertilizer-treated one, and efficiency of nitrogen applied was shown to be the highest in 100% treated digestate of the pig manure. Exchangeable cation and pH increased in the soil treated with digestate after harvesting, but salt was not accumulated. With these results, it was concluded that resource recycling in green town can be facilitated through the securement of arable lands for the application of digestates and the proper use of these fertilizers. Long-term effects of digestate application on the soil environment should be sustainingly studied.

• Journal of Korean Society of Forest Science
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• v.108 no.1
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• pp.40-49
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• 2019

Coarse woody debris (CWD), which is a component of the forest ecosystem, plays a major role in forest energy flow and nutrient cycling. In particular, CWD isolates carbon for a long time and is important in terms of slowing the rate of carbon released from the forest to the atmosphere. Therefore, this study measured the physiochemical characteristics and respiration rate ($R_{CWD}$) of CWD for Larix kaempferi and Pinus rigida in temperate forests in central Korea. In summer 2018, CWD samples from decay class (DC) I to IV were collected in the 14 forest stands. $R_{CWD}$ and physiochemical characteristics were measured using a closed chamber with a portable carbon dioxide sensor in the laboratory. In both species, as CWD decomposition progressed, the density ($D_{CWD}$) of the CWD decreased while the water content ($WC_{CWD}$) increased. Furthermore, the carbon concentrations did not significantly differ by DC, whereas the nitrogen concentration significantly increased and the C/N ratio decreased. The respiration rate of L. kaempferi CWD increased significantly up to DC IV, but for P. rigida it increased to DC II and then unchanged for DC II-IV. Accordingly, except for carbon concentration, all the measured characteristics showed a significant correlation with $R_{CWD}$. Multiple linear regression showed that $WC_{CWD}$ was the most influential factor on $R_{CWD}$. $WC_{CWD}$ affects $R_{CWD}$ by increasing microbial activity and is closely related to complex environmental factors such as temperature and light conditions. Therefore, it is necessary to study their correlation and estimate the time-series pattern of CWD moisture.

• The Journal of Engineering Geology
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• v.28 no.4
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• pp.565-582
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• 2018

We investigated the hydrochemical properties of ChusanYongchulso Spring located in Buk-myeon, Ulleung Island, focusing on the formation and characteristics of aquifers in and around the Nari caldera. Abundant pumice with high permeability and numerous fractures (including faults and joints) that formed as a result of caldera subsidence are widely distributed in the subsurface, favoring the formation of aquifers. Because of the presence of porous pyroclastic rocks with a high internal surface area, the water type of the springs is characterized by $NaHCO_3$, with upper stream waters and the upper spring being characterized by $NaHCO_3$ and NaCl, respectively. Components with a high coefficient of determination with EC are $HCO_3$, Na, F, Ca, Mg, Cl, $SiO_2$, and $SO_4$. The high concentrations of Na and Cl might be attributable to the main lithologies in the area, given that alkaline volcanic rocks are distributed extensively across Ulleung Island. Eh and pH, which are considered to be important indicators of water-rock interaction, are unrelated to most components. According to the results obtained from factor analysis, the variance explained by factor 1 is 54% and by factor 2 is 25.8%. Components with a high loading on factor 1 are F, Na, EC, Cl, $HCO_3$, $SO_4$, $SiO_2$, Ca, $NO_3$, and Mg, whereas components with a high loading on factor 2 are Mg and Ca, along with K, $NO_3$, and DO with negative loadings. It is suggested that the high concentrations of Na, Cl, F, and $SO_4$ are closely related to the presence of fine-grained alkaline pyroclastic rocks with high permeability and porosity, which favorintensewater-rock interaction. However, a wide-ranging investigation that encompasses methods such as geophysical prospecting and geochemical analysis (including isotope, trace-element, and tracer techniques) will be necessary to gain a better understanding of the groundwater chemistry, aquifer distribution, and water cycling of Ulleung Island.

• Journal of the Korean Electrochemical Society
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• v.24 no.3
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• pp.65-75
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• 2021

Coin cell is a basic testing platform for battery research, discovering new materials and concepts, and contributing to fundamental research on next-generation batteries. Li metal batteries (LMBs) are promising since a high energy density (~500 Wh kg^-1) is deliverable far beyond Li-ion. However, Li dendrite-triggered volume fluctuation and high surface cause severe deterioration of performance. Given that such drawbacks are strongly dependent on the cell parameters and structure, such as the amount of electrolyte, Li thickness, and internal pressure, reliable Li metal coin cell testing is challenging. For the LMB-specialized coin cell testing platform, this study suggests the optimal coin cell structure that secures performance and reproducibility of LMBs under stringent conditions, such as lean electrolyte, high mass loading of NMC cathode, and thinner Li use. By controlling the cathode/anode (C/A) area ratio closer to 1.0, the inactive space was minimized, mitigating the cell degradation. The quantification and imaging of inner cell pressure elucidated that the uniformity of the pressure is a crucial matter to improving performance reliability. The LMB coin cells exhibit better cycling retention and reproducibility under higher (0.6 MPa → 2.13 MPa) and uniform (standard deviation: 0.43 → 0.16) stack pressure through the changes in internal parts and introducing a flexible polymer (PDMS) film.

• Korean Journal of Ecology and Environment
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• v.54 no.4
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• pp.346-362
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• 2021

A sediment control dam is an artificial structure built to prolong sedimentation in the main dam by reducing the inflow of suspended solids. These dams can affect changes in dissolved organic matter (DOM) in the water body by changing the river flow regime. The main DOM component for Yeongju Dam sediment control of the Naeseongcheon River was analyzed through 3D excitation-emission matrix (EEM) and parallel factor (PARAFAC) analyses. As a result, four humic-like components (C1~C3, C5), and three proteins, tryptophan-like components (C2, C6~C7) were detected. Among DOM components, humic-like components (autochthonous: C1, allochthonous: C2~C3) were found to be dominant during the sampling period. The total amount of DOM components and the composition ratio of each component did not show a difference for each depth according to the amount of available light (100%, 12%, and 1%). Throughout the study period, the allochthonous organic matter was continuously decomposing and converting into autochthonous organic matter; the DOM indices (fluorescence index, humification index, and freshness index) indicated the dominance of autochthonous organic matter in the river. Considering the relative abundance of cyanobacteria and that the number of bacteria cells and rotifers increased as autochthonous organic matter increased, it was suggested that the algal bloom and consequent activation of the microbial food web was affected by the composition of DOM in the water body. Research on DOM characteristics is important not only for water quality management but also for understanding the cycling of matter through microbial food web activity.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.25 no.4
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• pp.35-42
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• 1980

To establish a generation acceleration technique, two crops a year at field condition of Suweon, 10 varieties different in their spring growth habit were tested with 6 different seeding time after harvesting. These materials were harvested on June 10, 19, 79 and tested for their seed production ability at varions seeding time from July I I to August 15 with a week interval. An immatured seed germination technique and green vernalization methods were applied in cycling generations and the results obtained were summarized as follows. 1. In summer growing, seedlings establishment after transplanting was better in earlier transplanting. 2. Heading time was remarkably enhanced by earlier transplanting. Considering the results of two years early or mid of July was the suitable time to plant the second summer crop. 3. Those varieties of spring growth habit expressed little variations in plant height among the varieties. In 1978 which is referred as warm year produced plant height as tall as 8-16cm and poor crop but produced good crop with 25-65cm plant height in 1979. 4. No definit tendency in the length of spike was. observed among the cultivars but longer spike was found in winter wheat compared to the spring. 5. Number of spikes per plant was ranged from 1 to 3 regardless the transplanting time in 1979. However, more spikes per plant were produced in early or mid of July transplanting and those varieties of higher growth habit than V did not produces any spikes. 6. Higher number of grains per spike was found at earlier transplanted varieties. Therefore, it is concluded that those materials of I-IV growth habit with mid or early July transplanting would be suitable in practical sense considering their ability of seed production. 7. Two-year results indicated that wheat crop can not tolerate the temperature level higher than average 32$^{\circ}C$ C at Suweon. In this regard, the cultivation schedule was established assuming average temperature condition like the year of 1979 which was possible to grow wheats.

• Korean Journal of Animal Reproduction
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• v.24 no.1
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• pp.49-57
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• 2000

This study was conducted to investigate the developmental potential of cloned embryos derived from bovine fetal fibroblast cells, and the effect of quiescent treatment, passage number and origin of donor cells on in vitro development of cloned embryos. Fetal skin and liver-derived fibroblast cells were transferred to enucleated oocytes after serum starvation or nontreatment (cycling). After electrofusion. reconstituted embryos were activated with $Ca^{＋＋}$-ionophore and cycloheximide, and cocultured for 7~9 days with BRL cells. Some blastocysts were transferred to recipient cows 7~8 days post estrus. The development rate to the blastocyst stage of serum starved cell-derived embryos was higher (25.3%) than that of actively dividing cells-derived embryos (15.9%), The rates of blastocyst formation were 23.1~25.0% after transfer of cell passaged 4 to 6 times, and 23.8 and 25.2% after transfer of fetal skin and liver cells, respectively. After embryo transfer, 34.4% and 15.6% of recipient cows were pregnant on Day 60 and 120, respectively, and one male calf was produced from skin-derived vitrified blastocyst. The result of this study showed that the development of cloned embryos. was enhanced by quiescent treatment, but did not different among the cells passaged 4 to 6 times, and between skin and liver cells. This result also confirms that offspring can be obtained from the vitrified clone embryo derived from fetal skin cell.

• Korean Journal of Remote Sensing
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• v.39 no.5_3
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• pp.1009-1029
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• 2023

Urban trees play a vital role in urban ecosystems,significantly reducing impervious surfaces and impacting carbon cycling within the city. Although previous research has demonstrated the efficacy of employing artificial intelligence in conjunction with airborne light detection and ranging (LiDAR) data to generate urban tree information, the availability and cost constraints associated with LiDAR data pose limitations. Consequently, this study employed freely accessible, high-resolution multispectral satellite imagery (i.e., Sentinel-2 data) to estimate fractional tree canopy cover (FTC) within the urban confines of Suwon, South Korea, employing machine learning techniques. This study leveraged a median composite image derived from a time series of Sentinel-2 images. In order to account for the diverse land cover found in urban areas, the model incorporated three types of input variables: average (mean) and standard deviation (std) values within a 30-meter grid from 10 m resolution of optical indices from Sentinel-2, and fractional coverage for distinct land cover classes within 30 m grids from the existing level 3 land cover map. Four schemes with different combinations of input variables were compared. Notably, when all three factors (i.e., mean, std, and fractional cover) were used to consider the variation of landcover in urban areas(Scheme 4, S4), the machine learning model exhibited improved performance compared to using only the mean of optical indices (Scheme 1). Of the various models proposed, the random forest (RF) model with S4 demonstrated the most remarkable performance, achieving R² of 0.8196, and mean absolute error (MAE) of 0.0749, and a root mean squared error (RMSE) of 0.1022. The std variable exhibited the highest impact on model outputs within the heterogeneous land covers based on the variable importance analysis. This trained RF model with S4 was then applied to the entire Suwon region, consistently delivering robust results with an R² of 0.8702, MAE of 0.0873, and RMSE of 0.1335. The FTC estimation method developed in this study is expected to offer advantages for application in various regions, providing fundamental data for a better understanding of carbon dynamics in urban ecosystems in the future.

• The Korean Journal of Archival Studies
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• no.80
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• pp.43-88
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• 2024

The National Archives and Records Administration (NARA) is a relatively quiet latecomer to the traditional archives of the Western world. Although the United States lacks a long history of organized public records·archives management, it has developed a modern system optimized for the American historical context. This system focuses on the systematic management and preservation of the vast amount of modern records produced and collected during the tumultuous 20th century. As a result, NARA has established a modern archival system that is optimized for the American historical context. The U.S. public records·archives management system is based on the principle that records·archives are the property of the American people and belong to the public. This concept originated during the British colonial era when records were used to safeguard the rights of the colonies as self-governing citizens. For Americans, records and archives have long been a symbol of the nation's identity, serving as a means of protecting individual freedoms, rights, and democracy throughout the country's history. It is natural, therefore, that American life and history should be documented, and that the recorded past should be managed and preserved for the nation's present and future. The public records·archives management system in the United States is the result of a convergence of theories, practices, lessons learned, and ideas that have been shaped by the country's history, philosophies, and values about records, and its unique experience with records management. This paper traces the origins of records and archives in the United States in a historical context to understand the organic relationship between American life and records. It examines the process of forming a modern public records management system that is both uniquely American and universal to the American context without falling into the two forms of traditions that reflect the uniqueness of American history.

• Journal of Embryo Transfer
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• v.22 no.1
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• pp.53-61
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• 2007

This study was investigated factors affecting the pregnancy rates after transfer of pronuclear microinjected embryos for the production of transgenic Korean black goats. Embryo transfer was carried out in 343 recipient Korean black goats from September 1999 to June 2000. Estrus was induced by the insertion of intravaginal progesterone devices $CIDR^(R)$ for 2 weeks. A single injection of 400 IU equine chorionic gonadotropin was administered at 48h before $CIDR^(R)$ removal to increase the proportion of does cycling and ovulation rate. Good quality embryos were prepared by microinjection of DNA into the pronuclei of fertilized goat oocyte and cultured in vitro. Pronuclear microinjected $1{\sim}8$ cell stage embryos were surgically transferred into the oviducts of the recipient at day 4 or 5 following $CIDR^(R)$ removal, and morula to blastocyst stage embryos were surgically transferred into uterus at day 9. Pregnancy was diagnosed by transrectal ultrasound scanning at $20{\sim}30d$ and 8 weeks following embryo transfer. The pregnancy rate was affected by several factors, such as estrus induction, the number of previous transfer, transfer site, stage of CL (corpus luteum), the number of recipient CL, stage of embryos and the number of transferred embryo. The pregnancy rate was significantly higher in recipients that came into estrus naturally than recipients that induced to come into estrus with $CIDR^(R)$(59.1% vs. 36.8%; P<0.05). The pregnancy rate was higher when the embryos were transferred into the left oviduct than transferred into the right oviduct (42.9% vs. 35.3%; P<0.05). The pregnancy rate of recipients with $CH_1$ (early) stage corpus hemorrhagicum in ovary was hi틴or than recipient with $CH_3$ (late) stage hemorrhagicum (47.5% vs. 17.9%; P<0.01). Higher pregnancy rates were obtained by transfer of 1-cell stage embryos into oviduct while late blastocysts (51.6% vs. 66.7%; P<0.01) into uterus. The pregnancy rates when 3 embryos were transferred to recipients were significantly higher than when 2 embryos we.e transferred (47.6% vs. 27.0%; P<0.05). Although there were no significant difference among the group, adhesion of reproductive organs, uterine size, ovulation rate of recipients, presence of large follicle and difficulty of transfer affected pregnancy rate of recipient. Higher pregnancy rates were obtained in the recipients with $8{\sim}15m$ diameter uterine horn as compared to the recipients with <5m diameter or >20mm diameter uterine hem (38.9%, 20% vs. 18.2%), in the recipients with large follicle in the ovulated ovary ipsilaterally (53.6% vs. 37.1%) and in the transfer which was carried out easily (39.2% vs. 27.8%, 0%). In conclusion, the high rate of pregnancy was achieved following transfer of pronuclear microinjected embryos when three or four 1-cell stage embryos were transferred into oviduct with $CH_1$ stage corpus hemorrhagicum in the ovary of recipient which came into estrus naturally.