• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.16 no.2
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• pp.165-172
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• 2018

As an approach for estimation of the droplet size in the molten salt-liquid metal extraction process, a droplet formation experiment at room temperature was conducted to evaluate the applicability of the Scheele-Meister model with water-mercury system as a surrogate that is similar to the molten salt-liquid metal system. In the experiment, droplets were formed through the nozzle and the droplet size was measured using a digital camera and image analysis software. As nozzles, commercially available needles with inner diameters (ID) of 0.018 cm and 0.025 cm and self-fabricated nozzles with 3-holes (ID: 0.0135 cm), 4-holes (ID: 0.0135 cm), and 2-holes (ID: 0.0148 cm) were used. The mercury penetration lengths in the nozzles were 1.3 cm for the needles and 0.5 cm for the self-fabricated nozzles. The droplets formed from each nozzle maintained stable spherical shape up to 20 cm below the nozzle. The droplet size measurements were within a 10% error range when compared to the Scheele-Meister model estimates. The experimental results show that the Scheele-Meister model for droplet size estimation can be applied to nozzles that stably form droplets in a water-mercury system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.1
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• pp.149-155
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• 2015

This paper proposes 5-MS/s 10-bit digital-to-analog converter(DAC) with the improved linearity. The proposed DAC consists of a 10-bit R-2R-based DAC, an output buffer using a differential voltage amplifier with rail-to-rail input range, and a band-gap reference circuit for the bias voltage. The linearity of the 10-bit R-2R DAC is improved as the resistor of 2R is implemented by including the turn-on resistance of an inverter for a switch. The output voltage range of the DAC is determined to be $2/3{\times}VDD$ from an rail-to-rail output voltage range of the R-2R DAC using a differential voltage amplifier in the output buffer. The proposed DAC is implemented using a 1-poly 8-metal 130nm CMOS process with 1.2-V supply. The measured dynamic performance of the implemented DAC are the ENOB of 9.4 bit, SNDR of 58 dB, and SFDR of 63 dBc. The measured DNL and INL are less than +/-0.35 LSB. The area and power consumption of DAC are $642.9{\times}366.6{\mu}m^2$ and 2.95 mW, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.228-228
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• 2007

전력선 통신용 비접촉식 커플러는 고속형(2~30 MHz)과 저속형(100~450KHz)으로 나누어 볼 수 있는데, 고속형은 현재 국내에서 독자적으로 개발되어 다양한 모델이 적용되고 있는 상황이지만, 저속형은 시작품수준으로 제조되어 있으나 신호전송 특성의 향상절구가 필요한 상황이다. 전력선 통신용 커플러는 전력선 또는 모뎀으로 통신신호를 전달하는 기능을 하는 것으로서, 전력선 통신을 위한 핵심부품이다. 따라서 본 연구에서는 100~450 KHz 대역에서 사용 가능한 저속형 비접촉식 커플러를 제조하기 위해, 권선조건, 대전류형 자심재료의 모의 해석, 노이즈 필터조건, 임피던스 매칭, 하우징방법 등의 각 공정 변수를 확립하고자 하였다. 자심재료의 모의해석에서 자심재료의 높이와 전력선 도체 단면적 변화는 자심재료의 전류포화특성에 영향을 미치지 않으며, 유효길이와 에어-갭 크기가 증가할수록 전류포화특성은 향상되는데, 자심재료의 내경이 64 mm일 때 자심재료의 폭((외경-내경)/2)은 15 mm 이상이어야 하고, 에어-갭은 약 $600\;{\mu}m$ 정도의 에어-갭을 형성시켜야함을 확인할 수 있었다. 또한 저속용 비접촉식 커플러 제조조건 실험에서 내경${\times}$외경${\times}$높이가 $64{\times}94{\times}140mm$인 자심재료를 이용하여 권선 수와 에어-갭을 각각 3회, $400{\sim}600\;{\mu}m$ 삽입했을 때, 가장 우수한 특성을 나타내었다. 그리고 저역 통과 필터를 출력부에 내장하여 통신신호 이외의 노이즈를 제거할 수 있었다. 본 연구에서 제조된 300 A급 지중선용 저속형 비접촉식 커플러는 내경${\times}$외경${\times}$높이가 $58{\times}1144{\times}158mm$이고, 100~450 KHz 통신대역에서 약$7{\pm}2dB$의 삽입손실을 나타내었다.

• Journal of Korean Philosophical Society
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• v.129
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• pp.341-366
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• 2014

This Thesis analyzes the two forms of Confucian Golden Rule(Shu恕) that were proposed by Zhu Xi朱熹 and Dai Zhen戴震 each other, and researches their ethical significances. Zhu Xi don't regards Shu as universal ethics by itself, while Dai Zhen identify Shu as the ground of universal ethics, According to this thesis, Zhu Xi thought that Shu has a danger of immoral misusage in some situation because Shu is so simplistic form of identification. Because this, Zhu Xi, for the purpose of blocking arbitrary misusage of Shu and holding universality of ethics, suggests that moral sincerity(Zhong忠) of subject is necessary to practice of Shu. Dai Zhen, however, criticizes Zhu Xi's Ethical Structure. In Dai Zhen's view, Zhu xi's idea that the subject has to establish his own morality through Zhong before practice Shu cannot make him escape from subjectivity necessarily. In this point, Dai Zhen revive Shu. His Shu concept means the reciprocity of human desires to each other. But Dai Zhen's idea, as Zhu Xi worried, has a danger of immoral misusage in some situation. On this problem, this thesis elucidates that Dai Zhen' desire concept is not individual various desires but is common basic desires of existence, thereby attests that Dai Zhen's Shu is safe from immoral misusage. This thesis claim that even if Zhu Xi's and Dai Zhen's position is so different, the ethical aims of two scholars is same. They both attempted to overcome the evil of subjectivism and to procure universality of ethics, furthermore to accomplish social fairness. Consequently, this thesis claims that two scholars both walked in same way because both wanted to establish the universality of Shu and to pursue realization of social fairness.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.4
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• pp.366-372
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• 2019

In this paper, we fabricated a capacitive humidity sensor with an IDT(Interdigitated) electrode using commercial polyimide containing fluorine, and its properties were measured and analyzed. First, in order to analyze the composition of commercial polyimide, EDS analysis was performed after patterning process on a silicon wafer. The area of the humidity sensor was $1.56{\times}1.66mm^2$, and the width of the electrode and the gap between the electrodes were $3{\mu}m$ each. The number of electrodes was 166 and the length of the electrode was 1.294mm for the sensitivity of the sensor. The fabricated sensor showed that the sensitivity was 24 fF/%RH, linearity <${\pm}2.5%RH$ and hysteresis <${\pm}4%RH$. As a result of measuring the capacitance value according to the frequency change, the capacitance vlaue decreased with increasing frequency. Capacitance deviations with 10kHz and 100kHz were measured as 0.3pF on average.

• Korean Journal of Heritage: History & Science
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• v.54 no.3
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• pp.52-67
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• 2021

This study is an attempt to explore the roles of and the collaborative relationship between Daheojang and Maedeupjang. Daheojang and Maedeupjang share a similar manufacturing process. However, in modern times, Daheojang totally disappeared, and Maedeupjang was designated as an intangible cultural property. The present study will investigate the role of Daheojang and Maedeupjang based on the literature of the Joseon dynasty. Daheojang were craftsmen who made bands and strings of woven or twisted silk strands. They made mangsu and tassels or made knots to produce magnificent artifacts. Maedeupjang complete all steps of the process, from refining, dyeing, combining threads, daheo, maedeup, to the tassel. Daheojang in the Joseon dynasty was the center of this process. Daheojang belonged to almost all Uigwe because it used items ranging from large uso to cushion straps. Dahoe is a craft with various items and techniques. It has been widely used to produce majestic items like formal dresses, ritual ceremony pieces, and mountings, as well as daily items like jodae, pocket straps, and norigae. Based on the records of Uigwe in the late Joseon dynasty, the study explored the collaborative relationship between Daheojang and Maedeupjang. Sambang, the room where both Daheojang and Maedeupjang belong, was the room to produce the royal chair. The royal chair essentially includes large uso. The large uso is an artifact that ties a knot in a thick circle more than two meters long. While Daheojang made rounded daheo, Maedeupjang made delicate and balanced knots. Also, they produced royal inscriptions together with a royal seal with decorative mangsu and a seal of thick rounded daheo. In order to learn about traditional technology, it is necessary to study the system of the times and social trends. Therefore, the study focused on Daheojang, who were common master craftsmen during the Joseon dynasty but now are not familiar to most people.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.2
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• pp.76-83
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• 2022

Since the 3D printing mortar is exposed to the atmosphere immediately after printing, moisture is largely evaporated from the surface of the layer. The evaporation of moisture on the surface of the layer greatly causes drying shrinkage and increases the risk of cracking and damage to the structure due to drying shrinkage. This study experimentally evaluated the shrinkage behavior of the initial age using the mortar used for 3D printing. The change in shrinkage was evaluated by comparing the shrinkage of the specimen cured by the sealing method and the atmospheric exposure method. In addition, compared with the case where type 1 cement was used 100%, the shrinkage amount was evaluated when 20% of fly ash was replaced and 10% of silica fume was used. In particular, the effect of three chemical admixtures applied using 3D printing on shrinkage was evaluated experimentally. When fly ash and silica fume were used, the shrinkage amount increased by 60 - 110% compared to the case when type 1 cement was used. The application of viscosity modifiers and shrinkage reducers reduced the shrinkage by at least 18% and at most 70% depending on the curing conditions. The temperature of the specimen temporarily decreased to 15 ℃ at the beginning of curing, and the correlation between the internal temperature of the specimen and the shrinkage behavior was observed.

• Composites Research
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• v.37 no.1
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• pp.7-14
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• 2024

Due to the structural characteristic of a double roller, the double roller can have various deformation behaviors depending on a gap block design, even if dimensions and loading conditions for the double roller are the same. Based on this feature, we propose a strategy for designing the gap block of the carbon-fiber reinforced plastic (CFRP) double roller to minimize defects (e.g., sagging and wrinkling), which can be raised during the product conveying process, with the pursue of the lightweight design. In the suggested strategy, analysis cases are first selected by considering main design parameters and engineering tolerances of the gap block, and then deformation behaviors of these selected cases are extracted using the finite element method (FEM). Here, to obtain the optimal gap block parameters that satisfy the purpose of this study, deformation deviations in the contact area are calculated and compared using the extracted deformation behaviors. Note that the contact area in this work is located between the product and the roller. As a result, through the design method of the gap block proposed in this work, it is possible to construct the CFRP double roller that can significantly decrease the defects without changing the overall sizes of the roller. A detailed method is suggested herein, and the results are evaluated in a numerical way.

• Journal of the Society of Disaster Information
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• v.20 no.1
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• pp.40-46
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• 2024

Purpose: In this study, in order to ensure the evacuation safety of plant facilities, we analyze the relationship between the height of smoke removal boundary walls, the presence or absence of smoke removal equipment, and evacuation safety. Method: Using fire and evacuation simulations, evacuation safety was analyzed through changes in the height of the smoke removal boundary wall, air supply volume and exhaust volume according to vertical dista. Result: In the case of visible drawings, if only 0.6m of boundary wall is used, the time below 5m reaches the shortest, and 1.2m of boundary width is 20% longer than when using smoke removal facilities. In the case of temperature, 1.2m is 20% longer than 0.6m when only the boundary width is used without smoke removal facilities. Conclusion: It was found that increasing the length of the smoke removal boundary wall could affect visibility, and installing a smoke removal facility would affect temperature. Therefore, it is determined that an appropriate smoke removal plan and smoke removal equipment should be installed in consideration of the process characteristics.

• Journal of Environmental Policy
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• v.9 no.2
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• pp.3-19
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• 2010

Anyang-cheon(stream) runs through southern metropolitan area of Seoul to Han-river in Korea. Due to fast growth of Seoul, the water quality and quantity problems in Anyang-cheon have occurred. To cope with the problems, the Integrated Watershed Management program for Anyang-cheon was adopted and a KRW 26.1 billion (USD 21.8 million) pilot project (construction of 4 facilities such as reservoir) is suggested for 4 sub-watersheds of Anyang-cheon, which cost will be shared by the 12 local governments (LG). Three cost division schemes are compared. By Scheme 1, if the cost is borne by the LG in a watershed where the facilities are constructed (no cost division scheme), the LG in I is to bear 0.58% of the total construction cost, LG in watershed II 29.54%, LG in IV 0%, LG in V 69.88%. In particular, LG in IV in this scheme bears no cost because no facility is constructed, even though watershed IV is the major beneficiary of the facility construction. Scheme 2 is to share the cost by length of streams in each sub-watershed and the suggested cost share for each sub-watershed is 13.76% by I, 7.34% by II, 45.87% by IV, and 33.03% by V. However, this cost division scheme is fair only under the false assumption that the bargaining powers of group of LGs are identical. To suggest a better and fair division rule, Shapley Value, a cooperative game solution, is used to suggest Scheme 3. In Scheme 3, Shapley Value measures the summation of average marginal contribution of each player in all possible coalitions as cost division scheme and is known to provide a fair division considering bargaining power. In the context of Anyang-cheon, LGs in upper stream have superior bargaining position. The result suggests the cost division is fair under Scheme 3, when the cost shares are 0.29% by I, 14.77% by II, 50% by IV, and 34.94% by V, respectively.