• Applied Chemistry for Engineering
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• v.32 no.1
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• pp.117-123
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• 2021

In this study, the composite was prepared by mixing SiOx, soft carbon, and carbon black and the electrochemical properties of lithium ion battery were investigated. The content of SiOx added to improve the capacity of the soft carbon anode material was varied to 0, 6, 8, 10, 20 wt%, and carbon black was added as a structural stabilizer for reducing the volume expansion of SiOx. The physical properties of prepared CB/SiOx/C composite were investigated through XRD, SEM, EDS and powder resistance analysis. In addition, the electrochemical properties of prepared composite were observed through the charge/discharge capacity, rate and impedance analysis of the lithium ion battery. The prepared CB/SiOx/C composite had an inner cavity capable of mitigating the volume expansion of SiOx by adding carbon black. The formed internal cavity showed a low initial efficiency when the SiOx content was less than 8 wt%, and low cycle stability when the content of SiOx was less than 20 wt%. The CB/SiOx/C composite containing 10 wt% of SiOx showed an initial discharge capacity of 537 mAh/g, a capacity retention rate of 88%, and a rate of 79 at 2C/0.1C. SiOx was added to improve the capacity of the soft carbon anode material, and carbon black was added as a structural stabilizer to buffer the volume change of SiOx. In order to use the CB/SiOx/C composite as a high-efficiency anode material, the mechanism of the optimal SiOx and the use of carbon black as a structural stabilizer was discussed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.139-147
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• 2021

Livestock manure is used as an organic fertilizer to replace chemical fertilizers after sufficient fermentation in an aerobic bioreactor. On the other hand, liquid manure disposal problems occur repeatedly because soil spraying is restricted during the summer when the crops are growing. To use liquid fertilizer (LF) as an additional nutrient source for crops, it is necessary to reduce the amount of suspended solids (SS) in the liquid fertilizer and secure stability problems against pathogenic microorganisms. This study examined the effects of the simultaneous SS removal and E.coli sterilization in the LF using the microbubble (MB) generator (FeMgO catalyst insertion). The remaining SS were further removed using the integrated microbubble and microfilter system. During the floating process in the MB device, the SS were removed by 57.9%, and the coliform group was not detected (16,200→0 MPN/100 mL). By optimizing the HRT of the integrated system, the removal efficiency of the SS was improved by 92.9% under the 0.1h of HRT condition. After checking the properties of the treated LF, 64.5%, 70.1%, 54.9%, and 51.5% of the TCOD, SCOD, PO4-P, and TN, respectively, were removed. The treated effluent from such an integrated system has a lower SS content than that of the existing LF and does not contain coliforms; therefore, it can be used directly as an additional fertilizer.

• Korean Journal of Psychosomatic Medicine
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• v.28 no.2
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• pp.143-154
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• 2020

Objectives : The purpose of this study was to examine cognitive and psychological characteristics of patients with military service suitability issues compared to the general psychiatric outpatients. Methods : 108 patients who visited psychiatric clinic center due to military service suitability issues and 80 general psychiatric patients were recruited from the Department of Psychiatry of university hospital. ANCOVA and chi-equare test were used to examine differences between two groups. Furthermore, we utilized paired t-test to compare the scrore within military group depending on when they performed the psychological assessment. Results : There were no significant differences between military group and general outpatient group in WAIS-IV scores. However, military group scored remarkably higher than control group on validity scales, F-r and Fp-r whereas they scored lower on validity scale, K-r. Furthermore, military group showed significantly higher on BDI and MMPI-2-RF, EID, RCd, RC2, RC3, COG, HLP, SFD, NFC, STW, SAVE, SHY, DSF, NEGE-r, INTR-r. As a result of comparison within the military group following the periods of assessment, military group did not show the significant differences on the overall scales of MMPI-2-RF. Conclusions : The present study showed that military group tends to report their psychological distress more exaggeratedly. In addition, they had significantly elevated not only emotional distress such as depression and anxiety but interpersonal problem. The implications and limitations were discussed along with some suggestions for the future studies.

• Korean Journal of Heritage: History & Science
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• v.53 no.4
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• pp.188-197
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• 2020

Termites play an important role as decomposers of the forest ecosystem, while simultaneously causing enormous damage to wooden structures. Currently, two species of subterranean termites have been reported in Korea, and termite damage to historical wooden buildings is occurring nationwide due to climate change, forest fertility, and the locational characteristics of historical wooden buildings. Subterranean termites make their nests underground or inside timber. Termites move underground and access wooden structures through the lower parts of the buildings, adjacent to the ground. Once termites attack the wooden structures, it not only spoils the authenticity of cultural heritage structure, but also hampers structural stability due to the decrease in the strength of the material. Therefore, it is important to prevent termite damage before it occurs. Chemical treatments are mainly used in Korea to control and prevent the damage. In foreign countries, physical barriers are also used to prevent entry to wooden buildings, along with chemical treatments. Physical barriers involve installing nets or particles that termites cannot pass through in the lower part of the building, around the pipes, and between the edges of the building or exterior walls and interior materials. Advantages of a physical barrier are that it is an eco-friendly method, maintains long-term effect after installation, and does not require the use of chemical treatments. Prior to applying physical barriers, studies into the characteristics of termite species must be undertaken. In this study, we evaluated the minimum passage size that each caste of Reticulitermes speratus kyushuensis can move through. We found that workers, soldiers, and secondary reproductive termites were able to pass through diameters of 0.7mm, 0.9mm, and 1.1mm respectively. Head height of termites was an important factor in determining the minimum passing size. Results from the current study will be used as a basis to design the mesh size for physical barriers to prevent damage by termites in historical wooden buildings in Korea.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.31 no.1
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• pp.8-15
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• 2021

TiO2 has been used in various fields such as solar cells, dental implants, and photocatalysis, because it has high physical and chemical stability and is harmless to the body. TiO2 nanofibers which have a large specific surface area also show a good reactivity in bio-friendly products and excellent photocatalysis in air and water purification. To fabricate TiO2 nanofibers, an electrospinning method was used. To observe the diameter of TiO2 nanofibers with fabrication variables, the fabrication variables was divided into precursor composition variables and process variables and microstructure was analyzed. The concentrations of PVP (Polyvinylpyrrolidone) and TTIP (Titanium(IV) isopropoxide) were selected as precursor composition variables, and inflow velocity and voltage were also selected as process variables. Microstructure and crystal structure of TiO2 nanofibers were analyzed using FE-SEM (Field emission scanning electron microscope) and XRD (X-ray diffraction), respectively. As-spun TiO2 nanofibers with an average diameter of about 0.27 ㎛ to 1.31 ㎛ were transformed to anatase TiO2 nanofibers with an average diameter of about 0.22 ㎛ to 0.78 ㎛ after heat treatment of 3 hours at 450℃. Anatase TiO2 nanofibers with an average diameter of 0.22 ㎛ can be expected to improve the photocatalytic properties by increasing the specific surface area. To change the average diameter of TiO2 nanofibers, the control of precursor composition variables such as concentrations of PVP and TTIP is more efficient than the control of electrospinning process variables such as inflow velocity and voltage.

• The Journal of Korean Society for Radiation Therapy
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• v.32
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• pp.85-92
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• 2020

Purpose: To find out the advantages of thermoplastic bolus compared to conventional bolus, which is mainly used in clinical practice, We evaluated Two cases in terms of dose and location reproducibility to assess Usability of thermoplastic Bolus for skin VMAT radiotherapy. Materials and Methods: Two patient's treated with left breast skin lesion were simulated using thermoplastic Bolus and planned with 2arc VMAT. the prescription dose was irradiated to 95% or more of the target volume. We evaluated The reproducibility of the bolus position by measuring the length of the air gap in the CBCT (Cone Beam CT) image. to evaluate dose reproducibility, we compared The dose distribution in the plan and CBCT and measured in vivo for patient 2. Results: The difference between the air gap in patient 1's simulation CT and the mean air gap (M1) during 10 treatments in the CBCT image was -0.42±1.24mm. In patient 2, the difference between the average air gap between the skin and the bolus (M2) during 14 treatments was -1.08±1.3mm, and the air gap between the bolus (M3) was 0.49±1.16. The difference in the dose distribution between Plan CT and CBCT was -1.38% for PTV1 D95 and 0.39% for SKIN (max) in patient 1. In patient 2, PTV1 D95 showed a difference of 0.63% and SKIN (max) -0.53%. The in vivo measurement showed a difference of -1.47% from the planned dose. Conclusion: thermoplastic Bolus is simpler and takes less time to manufacture compared to those produced by 3D printer. Also compared to conventional bolus, it has high reproducibility in the set-up side and stable results in terms of dose delivery.

• Journal of the Korean Applied Science and Technology
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• v.37 no.6
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• pp.1517-1527
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• 2020

This study is about the UV protection effect and water resistance of a multiple emulsion (W/O/W) sunblock cream applied with emotional engineering and reports an actual industrial case. Multiple emulsion system of sunblock cream has the characteristics of changing to a W/O type that is soft and moist when applied, and has excellent water resistance after absorption. Multiple emulsion cream is a highly functional sunblock cream that has both moisture and water resistance. It is a stable milky white cream with a viscosity of 36,000 cps. The organic sunscreen used for the sunscreen was ethylhexylmethoxycinnamate and bisethylhexyloxyphenolmethoxyphenyltriazine. Hexagonal zinc oxide and titanium dioxide that block both UVB and UVA were used. As a result of measuring the UV protection effect by the in-vitro method, the UV protection effect (SPF) is 78.9 for multiple emulsion cream, 76.7 for W/O cream, and 71.3 for O/W cream. It was found that the blocking effect was different. This obtained the highest effect value in the multiple emulsion. As a clinical (in-vivo) result of the UV protection effect, the SPF value representing the UV protection effect of the sunblock cream developed with a multiple emulsion system was 85.7, and the PA-value that blocks the UVA area was 26.5, and ++++. It was found that it has a corresponding high blocking effect. As a result of the water resistance test, the W/O/W formulation had a high waterproofing resistance of 93.8% even after 4 hours, W/O had 75.4%, and O/W had a low water resistance of 25.3%. In the results of the HUT test, it was found in the order of multiple emulsion sun block cream > hydrophilic cream > lipophilic cream. Based on the research results of this multiple emulsion, it is expected to be highly active as a sunblock cream dedicated to outdoor activities by improving the feeling of use, UV protection index, and water resistance. Therefore, in this study, a multiple emulsion system of sunblock cream is developed and has a characteristic that changes to a W/O type that has a soft and moist feeling when applied, and has excellent water resistance after absorption.

• Korean Journal of Agricultural and Forest Meteorology
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• v.22 no.4
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• pp.268-278
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• 2020

Flowering time has been put forward due to the recent abnormally warm winter, which often caused damages of flower buds by late frosts persistently. In the present study, cumulative chill unit and cumulative heat unit of Niitaka pear, which are required for releasing the endogenous dormancy and for flowering after breaking dormancy, respectively, were compared between flowering time prediction models used in South K orea. Observation weather data were collected at eight locations for the recent three years from 2018-2020. The dates of full bloom were also collected to determine the confidence level of models including DVR, mDVR and CD models. It was found that mDVR model tended to have smaller values (8.4%) of the coefficient of variation (cv) of chill units than any other models. The CD model tended to have a low value of cv (17.5%) for calculation of heat unit required to reach flowering after breaking dormancy. The mDVR model had the most accurate prediction of full bloom during the study period compared with the other models. The DVR model usually had poor skills in prediction of full bloom dates. In particular, the error of the DVR model was large especially in southern coastal areas (e.g., Ulju and Sacheon) where the temperature was warm. Our results indicated that the mDVR model had relatively consistent accuracy in prediction of full bloom dates over region and years of interest. When observation data for full bloom date are compiled for an extended period, the full bloom date can be predicted with greater accuracy improving the mDVR model further.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.16 no.1
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• pp.1-19
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• 2021

The purpose of this research is to improve the investment success rate for startups in the water industry for the development of the entrepreneurial environment of the Korean water industry. In this research, we identified investment determinants through prior research and stratified them, and then surveyed the investor group at the beginning of the start-up using the FGI method, and determined the order of the investment determinants of investors. At the same time, we classified 41 start-ups related to the water industry into two groups: the group that received investment and the group that did not in the early stages of the start-up. Then we investigated the understanding of the investor's investment determinants, ranked them, and compared them by using the AHP technique. Through this, this research proposes five implications. First, it is important for start-ups in the early stages to receive seed investment to revitalize investment for startups in the water industry. For this, startups need to understand investors and prepare to attract investment with the perspective of angel investors rather than the perspective of VC investors. Second, Start-ups in the water sector should consider that the characteristics of the founder are important in order to receive seed investment, and also need to define their business at the industry and market level, and provide relevant rationale to meet the expectations of investors who value industry expertise and experience, and to increase the possibility of seed investment, which is important in the early stages of a startup. Third, institutions, such as K-water(Korea Water Resources Corporation), that support water industry startups need to conduct open innovation business opportunities discovery programs linked to startups so that startups currently participating in the startup support program could have business opportunities from the business infrastructure of platform-forming companies in the water industry. In particular, such institutions should help founders develop their industrial expertise and careers by supporting this type of start-up preparation process through the participation of in-house venture founders. Fourth, when K-water uses the government start-up support fund to discover and foster founders, it should increase initial contact with seed investors, conduct more thorough verification of business plans, and develop programs that use government start-up support funds to prepare a business suitable for seed angel investors. Fifth, K-water should support seed by connecting funds for initial investment among funds operated by itself. It is also necessary to develop a program that links the company receiving the seed investment with VC investment, not angel investment in cooperation with the VC fund operation entity participating as an LP so that companies that have attracted seed investment could attract follow-up VC investment.

• Korean Journal of Plant Resources
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• v.34 no.1
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• pp.64-72
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• 2021

This study aimed to identify regions with a suitable growth environment for Ligusticum chuanxing Hort. and use basic data to identify appropriate cultivation and stable production strategies. Four main areas of cultivation were selected and the relationship between growth characteristics (aboveground and underground parts) and weather and soil environment was analyzed. Overall growth was found to be significantly higher in Pyeongchang. Atmospheric and soil temperatures showed a significant negative correlation with overall height from the ground, stem diameter, and growth characteristics of the underground part; leaf length and width were positively correlated. As insolation increased, the growth characteristics, excluding leaf size, showed a positive correlation. Soil characteristics such as organic matter (OM), N, P, and K showed negative correlations with the overall height of the upper part and growth characteristics of the underground part, including stem diameter. Analysis of roots indicated that OM, N, P, and K were essential and were absorbed through the soil. The OM, N, P, and K values in the Pyeongchang area, which showed the optimal growth, were lower than those in other areas. It is believed that these results can be used to select cultivation sites for L. chuanxing and establish cultivation technology in future.