• Journal of the Korean Electrochemical Society
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• v.22 no.2
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• pp.69-78
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• 2019

Lithium metal anode with the highest theoretical capacity to replace graphite anodes are being reviewed. However, the dendrite growth during repeated oxidation/reduction reaction on lithium metal surface, which results in poor cycle performance and safety issue has hindered its successful implementation. In our previous work, we solved this problem by using surface modification technique whereby a surface pattern on lithium metal anode is introduced. Although the micro-patterned Lithium metal electrode is beneficial to control Li metal deposition efficiently, it is difficult to control the mossy-like Li granulation at high current density ($>2.0mA\;cm^{-2}$). In this study, we introduce vinylene carbonate (VC) electrolyte additive on micro patterned lithium metal anode to suppress the lithium dendrite growth. Owing to the synergetic effect of micro-patterned lithium metal anode and VC electrolyte additive, lithium dendrite at a high current density is dense. As a result, we confirmed that the cycle performance was further improved about 6 times as compared with the reference electrode.

• Membrane Journal
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• v.28 no.6
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• pp.424-431
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• 2018

The gas separation performance of a mixed membrane structure based on a mixture of polyethersulfone (PES) and cobalt tetraphenylporphyrin-benzylimidazole (CoTpp-BIm) as an oxygen carrier was investigated. The CoTpp-BIm mixed PES membrane had an asymmetric structure with a mixture of finger structure and sponge-like structure, and the upper surface was dense. The gas separation performance test was carried out using $94%\;N_2$ gas and $6%\;O_2$ mixed gas. Oxygen and nitrogen permeability coefficients were measured at ${\Delta}P$ ranging from 15 to 228 cmHg and the permeate side of the PES membrane was maintained at vacuum level. The oxygen permeability coefficient of CoTpp-BIm mixed PES membranes increased as supplied pressure was decreased. When the supply pressure was 15 cmHg, the gas permeability ($P_{O_2}$) was 6676 Barrer, the $O_2/N_2$ selectivity (${\alpha}$) was 6.1, and the promoting factor (F) was 2.39. Based on these results, it was confirmed that the addition of CoTpp-BIm to the PES film improved the oxygen separation characteristics.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.22 no.5
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• pp.1-12
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• 2019

It is important to measure the height of trees as an essential element for assessing the forest health in urban areas. Therefore, an automated method that can measure the height of individual tree as a three-dimensional forest information is needed in an extensive and dense forest. Since airborne LiDAR dataset is easy to analyze the tree height(z-coordinate) of forests, studies on individual tree height measurement could be performed as an assessment forest health. Especially in urban forests, that adversely affected by habitat fragmentation and isolation. So this study was analyzed to measure the height of individual trees for assessing the urban forests health, Furthermore to identify environmental factors that affect forest growth. The survey was conducted in the Mt. Bongseo located in Seobuk-gu. Cheonan-si(Middle Chungcheong Province). We segment the individual trees on coniferous by automatic method using the airborne LiDAR dataset of the two periods (year of 2016 and 2017) and to find out individual tree growth. Segmentation of individual trees was performed by using the watershed algorithm and the local maximum, and the tree growth was determined by the difference of the tree height according to the two periods. After we clarify the relationship between the environmental factors affecting the tree growth. The tree growth of Mt. Bongseo was about 20cm for a year, and it was analyzed to be lower than 23.9cm/year of the growth of the dominant species, Pinus rigida. This may have an adverse effect on the growth of isolated urban forests. It also determined different trees growth according to age, diameter and density class in the stock map, effective soil depth and drainage grade in the soil map. There was a statistically significant positive correlation between the distance to the road and the solar radiation as an environmental factor affecting the tree growth. Since there is less correlation, it is necessary to determine other influencing factors affecting tree growth in urban forests besides anthropogenic influences. This study is the first data for the analysis of segmentation and the growth of the individual tree, and it can be used as a scientific data of the urban forest health assessment and management.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.64-64
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• 2019

Screening and identification of genetic resources based on their phytoconstituents and morphological characters potentially provide baseline data for researchers, breeders, and nutraceutical companies who wish to formulate a nutrient-dense diet and health beneficial supplement. Thus, we evaluated the amount of total phenolic content and major phenolic compounds; examined if phenolic compounds could be used as distinguishing factors for perilla genetic resources; and investigated the relation between some quantitative and qualitative morphological characters with the contents of phenolic compounds in 360 accessions obtained from National Agrobiodiversity Center gene bank, Jeonju, Korea. Total phenolic content (TPC) was estimated using Folin-Ciocalteu colorimetric assay. Individual phenolic compounds were determined using an Ultra-High Performance Liquid Chromatography system equipped with Photodiode Array detector. Considerable variations were observed in TPC (7.99 to 117.47 mg GAE/g DE), rosmarinic acid (RA) (ND to 19.19 mg/g DE), caffeic acid (CA) (ND to 0.72 mg/g DE), apigenin-7-O-diglucuronide (ADG) (ND to 1.24 mg luteolin equivalent (LUE)/g DE), scutellarein-7-O-glucuronide (SG) (ND to 4.32 mg LUE/g DE), and apigenin-7-O-glucuronide (AG) (ND to 1.60 mg LUE/g DE). RA was the most dominant phenolic compound in most accessions (95.3%) followed by SG. The adaxial leaf color was light green, green and dark green in 13.8%, 65.0%, and 21.1 % of the accessions, respectively. 78.8% of the accessions had light green color at the abaxial side with the remaining being described as green. Most of the accessions (96.9%) were cordate shape, the remaining being eclipse. Intensities of green pigment at abaxial and adaxial leaf surfaces were correlated with contents of individual phenolic compounds and TPC whereas leaf length and width had no correlation with TPC, CA and RA, and negatively correlated with ADG, AG, and SG. Leaf shape was not related with content of phenolic compounds, color of leaves, or the length or width of leaves. Accessions IT57426, IT157434, IT267710, and IT267712 which contained relatively high contents of TPC and major phenolic compounds (RA and SG) could be used for further research in breeding and bioassay test. Our study result showed the contents of total phenolics and individual phenolic compounds along with the morphological characters could be useful distinguishing factors for perilla genetic resources.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.10
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• pp.3-12
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• 2018

This research aims at analyzing the changes in residential environment after a residential environment improvement project focusing on the analysis into the physical environment of a residential environment improvement project, and examining in what direction the changes by residents' own efforts occurred after public support, such as infrastructure. The present residence development method has become different from the previous pulling down method and is focused on regeneration. By examining in what direction the target residence is being changed because of the development by residents' own efforts after the government's public investment at this time, this study also aims at investigating the direction to develop a guideline for residential improvement for later improvement of deteriorated residence. As for the contents of the analysis, changes in public support, such as infrastructure, and other areas after the residential environment improvement project were compared and analyzed from the land use, street system, and condition of buildings before the residential environment improvement project through field survey, geographic information system(GIS), registered land and building data and so on. The biggest change since the support from the government was that at the beginning of the project, the application of special provision of building laws and different financial supports led to lots of newly built buildings. Since then, their number has decreased rapidly, and in most cases, there have been some changes in part, such as changes in the use of land or repair of disposal tanks. Most newly built buildings were multi-household houses, and it has caused road capacity and parking lot capacity, etc., to be exceeded, which has worsened the pleasantness of the living environment. In addition, other problems have also appeared, for example, the lack of residence supporting facilities yet with a higher level of residential density. Regarding the changes in the residential environment after the residential environment improvement project, maintenance of houses were conducted in some degree as diverse alleviation policies to improve poor residence, yet the absence of the guideline for the direction of developing the whole district has made the residence environment more dense and deteriorated. To solve these problems, in advance to a residential improvement project, specific management methods based on short-, mid- and long-term plans for the direction of development by residents' own efforts and a sustainable guideline seem to be necessary.

• Journal of the Microelectronics and Packaging Society
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• v.28 no.2
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• pp.71-79
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• 2021

In this study, we have successfully fabricated the Sn-Ni paste and evaluated the bonding properties for high-temperature endurable EV (Electric Vehicle) power module applications. From evaluating of the micro-structural changes in the TLPS (Transient Liquid Phase Sintering) joints with Sn and Ni contents in the Sn-Ni pastes, a lack of Ni powders and Ni particle agglomerations by Ni surplus were observed in the Sn-20Ni and Sn-50Ni joints (in wt.%), respectively. In contrast, relatively dense microstructures are observed in the Sn-30Ni and Sn-40Ni TLPS joints. From differential scanning calorimetry (DSC) thermal analysis results of the fabricated Sn-Ni paste and TLPS bonded joints, we confirmed that the complete reactions of Sn with Ni to form Ni-Sn intermetallic compounds (IMCs) at bonding temperatures occurred, and there is no remaining Sn in the joints after TLPS bonding. In addition, the interfacial reactions and IMC phase changes of the Sn-30Ni joints under various bonding temperatures were reported, and their mechanical shear strength were investigated. The TLPS bonded joints were mainly composed of residual Ni particles and Ni₃Sn₄ intermetallic phase. The average shear strength tended to increase with increasing bonding temperature. Our results indicated a high shear strength value of approximately 30 MPa at a bonding temperature of 270 ℃ and a bonding time of 30 min.

• Journal of the Korean GEO-environmental Society
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• v.12 no.3
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• pp.55-61
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• 2011

Song-Do international city is the area developed in large-scale land reclamation. Song-Do area consists of reclamation layer, sedimentary layer(loose silt, soft clay and sand alternating) and residual layer from the ground surface. Therefore, using pile foundation is inevitable to build structures safely. In this area, driven PHC piles have been generally constructed in terms of environmental and economic conditions. As a result of analyzing 4 sites in Song-Do district 5 and 7 recently, the method of driving pile has many problems because of existence of rigid soil in sedimentary layer and installation of more than 30m piles. In this case, when installing piles by drive after pre-boring up to appropriate depth, the results of constructability analysis were very good. And in the economic efficiency, although 4% of construction cost rose, it was a very slight increase in comparison with improvement of workability. In the case of the stability, more than 70% compared to the allowable stress of piles was satisfied through the load test. As a result, when PHC piles is installed in Song-Do district, the proper construction method is that piles are located at bearing layer after boring rigid sand layer.

• Korean Journal of Food Science and Technology
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• v.52 no.6
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• pp.655-660
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• 2020

High amylose corn starch and dextrin (acid-treated at 30, 40 and 50℃ denominated as Dextrin30, Dextrin40 and Dextrin50) were added to non-fried instant noodles. X-ray diffraction pattern, water absorption, cooking loss, microstructure, and textural properties of non-fried instant noodles were investigated. The addition of high amylose corn starch/dextrin induced a slight peak intensity at 20o in the X-ray pattern indicating the insignificant formation of amylose-lipid complex. Non-fried instant noodles including high amylose corn starch/dextrin showed lower water absorption than the control. Dense microstructure in transverse section of noodles was observed in non-fried instant noodles including high amylose corn starch/dextrin except Dextrin50. Also, the addition of high amylose corn starch/dextrin induced low tensile strength, high firmness, and high stickiness. However, non-fried instant noodles containing Dextrin50 showed a loose microstructure and high cooking loss (3.98%), which might be associated with the textural properties such as the lowest tensile strength (0.17 N), lowest increase in firmness (46.77 N) and highest stickiness (18.43 N).

• The Journal of the Korea Contents Association
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• v.21 no.6
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• pp.285-294
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• 2021

This study analyzes the factors that determine the attitude toward the electronic wristband(smartband) to check the position of self-quarantine subjects due to COVID-19. Furthermore, I analyze the interaction of class and age among the factors that determine attitudes toward the electronic wristband. In this study, the attitude toward self-quarantine electronic wristband is analyzed as a binary logit model, focusing on class and age. As a result of the analysis, the middle class significantly agreed with the self-quarantine electronic wristband compared to the lower class, and the older the person, the more in favor. On the other hand, the interaction between the class and the age shows that the age weakens the positive effect on the attitude of the self-quarantine electronic wristband in the middle and upper middle classes. The implication of this study is that it is necessary to push for mandatory electronic wristband in areas with high proportion of high-aged people with positive attitude toward self-quarantine electronic wristband and in the same age group, the approval rate is low, so it is necessary to promote mandatory electronic wristband in areas where the vulnerable class is dense.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.39 no.2
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• pp.93-101
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• 2021

Recently, with the urban redevelopment and the spread of the planned cities, there is increasing interest in the wind environment, which is related not only to design of buildings and landscaping but also to the comfortability of pedestrians. Numerical analysis for wind environment prediction is underway in many fields, such as dense areas of high-rise building or composition of the apartment complexes, a precisive 3D building model is essentially required in this process. Many studies conducted for wind environment analysis have typically used the method of creating a 3D model by utilizing the building layer included in the GIS (Geographic Information System) data. These data can easily and quickly observe the flow of atmosphere in a wide urban environment, but cannot be suitable for observing precisive flow of atmosphere, and in particular, the effect of a complicated structure of a single building on the flow of atmosphere cannot be calculated. Recently, drone photogrammetry has shown the advantage of being able to automatically perform building modeling based on a large number of images. In this study, we applied photogrammetry technology using a drone to evaluate the flow of atmosphere around two buildings located close to each other. Two 3D models were made into an automatic modeling technique and manual modeling technique. Auto-modeling technique is using an automatically generates a point cloud through photogrammetry and generating models through interpolation, and manual-modeling technique is a manually operated technique that individually generates 3D models based on point clouds. And then the flow of atmosphere for the two models was compared and analyzed. As a result, the wind environment of the two models showed a clear difference, and the model created by auto-modeling showed faster flow of atmosphere than the model created by manual modeling. Also in the case of the 3D mesh generated by auto-modeling showed the limitation of not proceeding an accurate analysis because the precise 3D shape was not reproduced in the closed area such as the porch of the building or the bridge between buildings.