• Membrane Journal
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• v.29 no.5
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• pp.263-275
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• 2019

In the present study, thickness of MOR zeolite membranes was controlled by changing seed size, seeding amount, and aging time of hydrothermal solution, and then effect of membrane thickness on pervaporative ethanol dehydration for 90 wt.% ethanol-water mixture was investigated. First, nanosize MOR zeolite seeds with a diameter of 20 to 30 nm was successfully prepared by planetary milling a laboratory synthesized MOR zeolites and the coating amount was controlled by seed concentration and infiltration volume of coating solution during vacuum-assisted seeding. As seeding amount decreased, membrane thickness was reduced up to around $4{\mu}m$. The MOR zeolite membrane having a thickness of $4{\mu}m$ showed a water/ethanol separation factor of 760 and water flux of $1.0kg/m^2h$. The excellent water flux was due to the reduced membrane thickness which was derived from the nanosize seed. Therefore, it could be concluded that membrane thickness control by using nanosize seed can be a crucial factor to improve pervaporative water flux of MOR zeolite membrane.

• Journal of the Microelectronics and Packaging Society
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• v.28 no.2
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• pp.65-70
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• 2021

In this study, interfacial properties and mechanical properties of joints were reported after Cu pads finished with organic solderability preservative (OSP) on flame retardant-4 (FR-4) printed circuit board (PCB) and electronic components were joined with a Sn-57Bi-1Ag solder paste by using a laser bonding process. The laser bonding process was performed under various bonding conditions with changing a laser power and a bonding time and effects of bonding conditions on interfacial and mechanical properties of joints were analyzed. In order to apply for industry, properties of bonding joints using a reflow bonding process which are widely used were compared. When the laser bonding process were performed, we observed that Cu₆Sn₅ intermetallic compounds (IMCs) were fully formed at the interface although the bonding times were very short about 2 and 3 s. Furthermore, void formations of the joints by using the laser bonding process were suppressed at the joints with comparing to the reflow bonding process and shear strengths of bonding joints were higher than that by using the reflow bonding process. Therefore, in spite of a very short bonding time, it is expected that joints will be stably formed and have a high mechanical strength by using the laser bonding process.

• Journal of Korean Society on Water Environment
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• v.27 no.4
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• pp.467-474
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• 2011

In an effort to investigate water pollution characteristics of Juam lake, water samples were collected from three sites (Sites A, B, and C) of Oenam stream which is a typical tributary of rural watershed in the lake and analyzed for N concentration and the corresponding isotope ratio (${\delta}^{15}N$) of ${NO_3}^-$. Concentrations of ${NO_3}^-$ were not dramatically different among the sites; $0.8{\pm}0.2mgNL^{-1}$ (range: $0.0{\sim}4.3mgNL^{-1}$) for Site A, $1.1{\pm}0.2mgNL^{-1}$ ($0.0{\sim}4.3mgNL^{-1}$) for Site B, and $1.1{\pm}0.1mgNL^{-1}$ ($0.1{\sim}2.6mgNL^{-1}$) for Site C. Meanwhile, ${\delta}^{15}N$ tended to decrease with river flow; it was highest for Site A ($45.5{\pm}5.3$‰) followed by Site B ($19.7{\pm}2.0$‰) and Site C ($8.7{\pm}1.5$‰). Such high ${\delta}^{15}N$ values of ${NO_3}^-$ in Site A suggested that ${NO_3}^-$ derived from livestock feedlot (specifically livestock excrete of which ${\delta}^{15}N$ is higher than 10‰) is the predominant pollution sources despite mountainous area occupied the most of land-use in the watershed. Using the two-sources isotope mixing model, it was estimated that the contribution of cropping activities (i.e. fertilization) became greater in down-stream area (Sites B and C) due to the higher agricultural land-use than the up-stream area (Site A). Particularly, during the active cropping season, the low contribution of organic pollution sources indicated that domestic sewage was not the predominant pollution source. Therefore, it was suggested that agricultural sources such as livestock farming and cropping rather than mountainous and residential are the dominant sources of water pollution in the study area. These results could be effectively utilized in elucidating water pollution sources in rural areas and selecting water management practices.

• The Journal of Korean Philosophical History
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• no.59
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• pp.287-312
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• 2018

Confucianism which pursues the right relationship between person and person, depicts the ideal that moral individuals contribute to community development. In the 16th century, Toegye Yi Hwang, the authority of Korean Confucianism, reflected his educational intentions and interests and made the whole of the body of Confucianism and the whole process of the study into a series of 10 paintings 'Ten Diagrams of Sage Learning'. The purpose of the education which is claimed in the 'Ten Diagrams of Sage Learning' is to become a saint, and it ultimately coincides with the purpose of moral education which is to be introspective and practical moral man. The whole theme of 'Ten Diagrams of Sage Learning' is related to revealing the principles of humanity and morality in order to restore human nature on the basis of piety. Piety(敬) is also a purpose and a method of self-discipline, and is the main content. The method of education for traditional confucianism is aiming for the organic integration of purpose, content and method of education and reveals the consistency of the combination of knowledge and behavior in content and method. Exploring the universal value of traditional culture and re-raising moral culture that is important in traditional education is to discuss that what is valid for the present and the future is derived from the past tradition. That may be useful in solving today's educational problems. Especially, it is very meaningful to adopt a reflective approach to cultivate talented people who can 'realize oneself' and 'care for the community' which is the ultimate goal of education through analyzing the essence of moral education pursued by traditional education.

• (The)Study of the Eastern Classic
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• no.56
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• pp.241-265
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• 2014

This paper looked at the existing situation and the uniqueness of the Hasu(河西) kim Inhu(金麟厚)'s collection of works. As a result, The first edition includes a piece missing in the second edition. For the title of the same work, the second edition differs from the third edition. And in the third edition, The missing piece is found through the annual report. This research found the performance that were found missing pieces. But I did not review for that depth meaning, and postpone it to a later date.

• Journal of Biomedical Engineering Research
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• v.42 no.6
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• pp.259-267
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• 2021

Recently, the market for personal health care and medical devices based on Bluetooth Low Energy(BLE) has grown rapidly. BLE is being used in various medical data communication devices based on low power consumption and universal compatibility. However, since data errors occurring in the transmission of medical data can lead to medical accidents, it is necessary to analyze the causes of errors and study methods to reduce data error. In this paper, the minimum communication speed to be used in medical devices was set to at least 800 byte/sec based on the wireless electrocardiography regulations of the Ministry of Food and Drug Safety. And the data loss rate was tested when data was transmitted at a speed higher than 800 byte/sec. The factors that cause communication data error were classified, and the relationship between each factor and the data error rate was analyzed through experiments. When there were two or more activated peripherals connected to the central, data error occurred due to channel hopping and bottleneck, and the data error rate increased in proportion to the communication distance and the number of activated peripherals. Through this experiment, when the BLE is used in a medical device that intermittently transmits biosignal data, the risk of a medical accident is predicted to be low if the number of peripherals is 3 or less. But, it was determined that BLE would not be suitable for the development of a biosignal measuring device that must be continuously transmitted in real time, such as an electrocardiogram.

• Research in Plant Disease
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• v.28 no.1
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• pp.39-45
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• 2022

Patterns of occurrence of tomato yellow leaf curl virus (TYLCV) and tomato chlorosis virus (ToCV) with whitefly on summer-cultivated tomato in Gwangju-si, Gyeonggi Province were surveyed using multiplex reverse transcription-polymerase chain reaction in 2020. In addition, distribution of the whiteflies species and their viral transmission rates were investigated throughout the tomato growing season. The infection rates of TYLCV and ToCV increased sharply during harvest, and the single infection rates were 30.9% and 5.0%, respectively, with a mixed infection rate of the two viruses being the highest at 52.2%. Single infection with TYLCV and double infections with TYLCV and ToCV accounted for the majority with 83.1%. Bemisia tabaci were dominant over Trialeurodes vaporariorum in greenhouse grown plants, and all of the investigated B. tabaci biotypes were identified as Mediterranean (MED, formerly known as Q biotype). The transmission rate of TYLCV, detected in every sampled B. tabaci MED population, was 21.4%, and the mixed transmission rate with ToCV was 35.5%. Viruliferous MED whiteflies with ToCV showed a higher rate than that of T. vaporariorum. In the transplant stage, viruliferous rate of both TYLCV and ToCV of B. tabaci was 42.7%; this rate was highest in the harvest stage. In examination of tomato yield, the increase in the mixed infection rate of TYLCV and ToCV led to complete yield loss. When the mixed infection rate increased by 10%, the yield decreased by 405.4 kg/10a.

• The Journal of the Acoustical Society of Korea
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• v.41 no.5
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• pp.481-491
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• 2022

The active sonar transmission system consists of a transmitter that outputs an electrical signal and an underwater acoustic transducer that converts the amplified electrical signal into an acoustic signal. In general, the transmitter output characteristics are dependent on load impedance, and an underwater acoustic transducer, which is a transmitter load, has a characteristic that the electrical impedance varies largely according to frequency when driven. In such a variable impedance condition, the output of the active sonar transmission system may become unstable. Hence, this paper proposes a design and control technique of a sonar transmitter for transmitting a stable transmission signal even under variable impedance conditions of an underwater acoustic transducer in an active sonar transmission system. The electrical impedance characteristics of the underwater acoustic transducer are experimentally analyzed, and the sonar transmitter is composed of a single-phase full-bridge inverter, an LC filter, and a matching circuit. In this paper, the design and output control method of the sonar transmitter is proposed to protect the transmitter and transducer. It can secure stable output voltage characteristics even if it transmits the Linear Frequency Modulation (LFM) signal. The validity is verified through the simulation and the experiment.

• Journal of the Korean Society of Floral Art and Design
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• no.42
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• pp.145-156
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• 2020

The purpose of this study was to investigate status survey on flower products with high sales by item and peak season. The survey was implemented for 103 people who are running flower shop and are members of association for Engineer Floral Design who are acquired Craftsman Floral Design and Engineer Floral Design. The result of this study, the peak season for the sale of flower product is showed May (52.0%) and February (24.3%). The reason for the selection was in May, month of family, teacher's day, etc. in February, personnel transfer and graduation ceremony. As a result of researching flower products with high sales volume by category, Cut flowers were ranked the first place of bouquet (51.5%%, 40.3%) and the second place of basket (28.8%, 37.5%) on annual and peak season. And also, Corsage, which was 6^th (1.8%) in the annual sales volume survey, increased to 3^rd (8.0%) during peak season. Pot plants were ranked 1st of foliage plant (50.6%, 51.3%) and 2nd tropical orchid·oriental orchids (27.4%, 28.3%) on annual and peak season. And also, Charcoal and bonsai, which were unresponsive in the annual sales survey, increased sales volume to 0.7% and 2.6%, respectively, during peak season. Processed flowers were highest ranked dry flower (45.3%, 39.5%), preserved flower (27.7%, 37.2%) on both non peak season and peak season. And then followed by artificial flower, pressed flower and collage.

• Journal of the Korean Society of Floral Art and Design
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• no.43
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• pp.57-79
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• 2020

The purpose of this study was to investigate the effects of emotion and EEG of people with mental illness by vocational rehabilitation program based on horticultural therapy. The subjects of the study were three people with mental illness who were training in a vocational rehabilitation team at a health center located in G city, Gyeongsangbuk-do. The result of this study, positive affect increased and negative affect decreased. The result of EEG inspection was increased 17.27% on pre test to 21.39% on post test for Theta wave and 39.66% on pre test to 49.02% on post test for Alpha wave in case of subject A. Also Beta wave was decreased 27.53% on pre test to 17.54% on post test. Subject B increased Alpha wave 29.70% on pre to 31.82% on post. Subject C increased Alpha wave 26.30% on pre to 49.42% on post. Beta wave decreased 29.85% on pre to 16.13% on post. Theta wave, when creatively idea or thought occurs, alpha wave when safety and focusing was increased and beta wave when stress, tension and anxiety was decreased. As a result of profits analysis, subject A spent cost a total of 101,700 won for material and achieve profits of 203,400 won by setting a sales price. Therefore, gain the 101,700 won of net revenue. Subject B spent cost a total of 81,000 won for material and achieve profits of 162,000 won by setting a sales price. Therefore, gain the 81,000 won of net revenue. Subject C spent cost a total of 56,200 won for material and achieve profits of 112,400 won by setting a sales price. Therefore, gain the 56,200 won of net revenue.