• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.702-709
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• 2018

A quick-hardened concrete track was developed to improve the aged ballasted track to a concrete track, and applied to earthworks and tunnels of main and urban railways. Rebars for reinforcement are not generally applied to prestressed concrete sleepers. On the other hand, many cracked sleepers have been observed in railroad sites. A wide sleeper, which is one of the main components of quick-hardened concrete track, should be structurally safe and crack-resistant in a ballasted and concrete track to avoid this problem. In particular, a wide sleeper manufactured by a post-tension method must have reinforcing bars applied to the rail-seat section. In this paper, static tests, dynamic tests, and fatigue tests were carried out to compare the flexural strength and crack resistance performance of a wide sleeper with and without reinforcing bars for a quick-hardened concrete track. As a result of the test, if some reinforcing bars are applied appropriately to the rail-seat section of a wide sleeper, it will be possible to prevent the occurrence of cracks, delay the expansion of the crack width, and the flexural fracture.

• Journal of the Korea Fashion and Costume Design Association
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• v.5 no.1
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• pp.33-45
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• 2003

This is a study that examines the fashion changes in the 20th century in terms of various subcultures in the period. Starting from defining the concept and the developing process of subculture, this study traces the history of subcultural styles from 1930s to 1990s, focusing on the way each generation resisted the main stream through its styles. This study is intended to provide a theoretical frame on the understanding of subcultural styles, with a close examination of its formative and developing process and characteristics. This study understands subcultural style as a way of deviate or resistant expression within a society. It differentiates itself from the main style by deliberately and publicly asserting its own identity, and, as a result, realizes in the form of fashion its repressed subconsciousness, resistance to the alienation from the society, and deviation from the normative ethics and morality of a society. The four types of subcultural styles presented in chapter 4 are based on their form of resistance, and they are classified and analyzed as follows: The first type is revision, which tries to revise and change the given form by adding new elements. There are two kinds of revision, one is dressing up, which dresses for success, and the other is minimal dressing. Hyperbole is the second type, which resists by emphasizing or hyperbolizing the main stream with its erotic, nihilistic, or dynamic forms. Two kinds of hyperbole are examined, one is hyperbole of masculinity, and the other is ostentatious hyperbole. The third type is reversal and rejection, which reverses the forms from the established sign system into its own secret code, or rejects the traditional taboos. This type include no dressing, and the reversal of sex identity. Isolation and redrawal is the fourth type, which tries to distance itself from the ritual code of the day. This type is divided into dressing of the escape from time, and dressing of the escape from space. The first group of this type is characterized by nostalgia or futurism. An emphasis is given on ethnicity, naturalism, or a closed space within a city in dressing of the escape from space. In conclusion, it can be said that subcultural style puts the foremost importance on individual freedom. Since 1990s, the distinction between the subcultural styles and high fashion gets somewhat blurred, while the liberal, sexual, life stylistic tension between the two groups are heightened.

• Journal of the Korean Applied Science and Technology
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• v.31 no.2
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• pp.231-237
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• 2014

The supercritical fluids (SCFs) have been widely used for material synthesis and processing due to their remarkable properties including low viscosity, high diffusivity and low surface tension. Carbon dioxide is one of the suitable solvents in SCFs processes in terms of its advantages such as easy processibility (with low critical temperature and pressure), inexpensive, nonflammable, nontoxic, and readily available. However, it has generally low solubility for high molecular weight polymers with the exception of fluoropolymers and siloxane polymers. Therefore, hydrocarbon solvents and hydrochlorofluorocarbons have been used for various SCFs process by its high solubility for high molecular weight polymers. In this report, a PMMA/clay nanocomposites were fabricated by using supercritical fluid process. The $Na^+$-MMT(montmorillonites)was modified by a fluorinated surfactant which is able to enhance compatibility with the chlorodifluoromethane(HCFC-22) and thus, improve dispersability of the clay in the polymer matrix. The PMMA/fluorinated surfactant modified clay nanocomposite shows enhanced mechanical and thermal properties which characterized by X-raydiffraction(XRD), Thermo gravimetric analysis(TGA), Dynamic mechanical analysis (DMA) and Transmission electron microscopy (TEM).

• Applied Chemistry for Engineering
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• v.30 no.4
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• pp.435-444
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• 2019

In this study, two types of nonionic saccharide biosurfactants, GP-6 and GP-7, were prepared from coconut oil and the structure of resulting products was investigated by FT-IR, $^1H-NMR$ and $^{13}C-NMR$ spectrophotometer. The interfacial properties of GP-6 and GP-7 were found to be excellent from interfacial property measurements such as critical micelle concentration, static and dynamic surface tensions, interfacial tension, emulsification power, wetting property and foam stability. Detergency test evaluated by using a Terg-o-tometer showed moderately good detergency compared to that of conventional surfactants used in detergent formulations. Biodegradability, acute oral toxicity, acute dermal irritation and acute eye irritation tests revealed that both surfactants possess excellent mildness and superior environmental compatibility indicating the potential applicability to detergent products formulations. In particular, GP-6 can be considered as a strong candidate in detergent formulations since it is more surface active, mild and readily biodegradable than GP-7.

• Tuberculosis and Respiratory Diseases
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• v.82 no.3
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• pp.251-260
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• 2019

Background: Beyond its current function as a rescue therapy in acute respiratory distress syndrome (ARDS), extracorporeal membrane oxygenation (ECMO) may be applied in ARDS patients with less severe hypoxemia to facilitate lung protective ventilation. The purpose of this study was to evaluate the efficacy of extended ECMO use in ARDS patients. Methods: This study reviewed 223 adult patients who had been admitted to the intensive care units of 11 hospitals in Korea and subsequently treated using ECMO. Among them, the 62 who required ECMO for ARDS were analyzed. The patients were divided into two groups according to pre-ECMO arterial blood gas: an extended group (n=14) and a conventional group (n=48). Results: Baseline characteristics were not different between the groups. The median arterial carbon dioxide tension/fraction of inspired oxygen ($FiO_2$) ratio was higher (97 vs. 61, p<0.001) while the median $FiO_2$ was lower (0.8 vs. 1.0, p<0.001) in the extended compared to the conventional group. The 60-day mortality was 21% in the extended group and 54% in the conventional group (p=0.03). Multivariate analysis indicated that the extended use of ECMO was independently associated with reduced 60-day mortality (odds ratio, 0.10; 95% confidence interval, 0.02-0.64; p=0.02). Lower median peak inspiratory pressure and median dynamic driving pressure were observed in the extended group 24 hours after ECMO support. Conclusion: Extended indications of ECMO implementation coupled with protective ventilator settings may improve the clinical outcome of patients with ARDS.

• Journal of the Society of Disaster Information
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• v.18 no.3
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• pp.646-659
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• 2022

Purpose: In this study, we developed a 4-way sway prevention brace that efficiently reduces the installation area and has excellent stability and seismic performance compared to the conventionl sway prevention brace used in existing firefighting facilities. The performance and reliability of the developed 4-way way prevention brace were analyzed by the tensile, compression tests and seismic tests. Method: As the static test, 4-way sway prevention braces were installed on the horizontal and vertical pipes to perform the tensile and compression tests based on the KFI certification standard and the maximum movement was measured at the rated load. As a dynamic test, 4-way sway prevention braces were installed in the pipes filled with water, and the test response spectrum to the input excitation wave were measured through the acceleration sensors. After the seismic tests, separation, failure, and local deformation of the pipes, and 4-way sway prevention braces were not observed. Result: The results of the tensile and compression tests indicated that the maximum movement of the pipe during tension and compression was 50% to 70% or less compared to the certification values, indicating that the performances of the 4-way sway prevention braces were very excellent. The results of the the seismic tests indicated that the test response spectrum of the 4-way sway prevention braces is within the required response spectrum. Conclusion: In this study, it was found that the 4-way sway prevention braces satisfied the KFI certification standard and were superior compared to the existing sway prevention brace in terms of the stability, cost, and installation area.

• Membrane Journal
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• v.32 no.4
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• pp.253-263
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• 2022

This study suggests a guideline for designing unit process of wastewater reuse in terms of a maintenance of the process based on critical parameters to draw a high quality performance of RO unit. Defining the parameters was done by applying membrane integrity test (MIT) in pretreatment process utilizing lab-scale MF. SDI is utilized for judging whether permeate is suitable to RO unit. However, result said TOC concentration matching with particle count analysis is better for judging the permeate condition. When membrane test pressure (P_test) was measured to derive log removal value in PDT, virgin state of membrane fiber was used to measure dynamic contact angle utilizing surface tension of the membrane fiber. Actually, foulant affects to the state of membrane surface, and it decreases the P_test value along with time elapsed. Consequently, LRV_DIT is also affected by P_test value. Thus, sensitivity of direct integrity test descends with result of P_test value change, so P_test value should be considered not the virgin state of the membrane but its current state. Overall, this study focuses on defining design parameters suitable to MF pretreatment for RO process in wastewater reuse by assessing its impact. Therefore, utilities can acknowledge that the membrane surface condition must be considered when users conduct the direct integrity test so that P_test and other relative parameter used to calculate LRV_DIT are adequately measured.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.1
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• pp.67-75
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• 2023

In this study, the dynamic characteristics of an offshore platform being installed and physical phenomena are analyzed from the perspective of interaction between operation and maneuvering simulation using a real-time Maneuvering & Operation simulator of Shipbuilding & Marine Simulation Center at Tongmyong University. It was simulated to install the semi-submersible drilling rig moored by 8 mooring lines according to a scenario that is similar to it on the real sea, and 4 tug boats for position keeping of the rig and an offshore support vessel for hook-up of the mooring lines were operated. During the simulation, the motion, trajectory, tension of the objects were output in real time, and they were analyzed at each work procedure. This study about the simultaneous simulation of operation and maneuvering showed the detailed motion of the offshore platform and ships on the operation procedure and the interaction between operation and maneuvering in specific environment condition. Also, it confirmed that the simulation can be utilized to determine the possibility of offshore platform installation in specific situations.

• Journal of Korean Society of Steel Construction
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• v.22 no.1
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• pp.1-12
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• 2010

According to the capacity design concept which forms the basis of the current steel seismic codes, the braces in concentrically braced frames (CBFs) should dissipate seismic energy through cyclic tension yielding and cyclic compression buckling while the beams and the columns should remain elastic. Brace buckling in inverted V-braced frames induces unbalanced vertical forces which, in turn, impose the additional beam moments and column axial forces. However, due to difficulty in predicting the location of buckling stories, the most conservative approach implied in the design code is to estimate the column axial forces by adding all the unbalanced vertical forces in the upper stories. One alternative approach, less conservative and recommended by the current code, is to estimate the column axial forces based on the amplified seismic load expected at the mechanism-level response. Both are either too conservative or lacking technical foundation. In this paper, three combination rules for a rational estimation of the column axial forces were proposed. The idea central to the three methods is to detect the stories of high buckling potential based on pushover analysis and dynamic behavior. The unbalanced vertical forces in the stories detected as high buckling potential are summed in a linear manner while those in other stories are combined by following the SRSS(square root of sum of squares) rule. The accuracy and design advantage of the three methods were validated by comparing extensive inelastic dynamic analysis results. The mode-shape based method(MSBM), which is both simple and accurate, is recommended as the method of choice for practicing engineers among the three.

• (The) Research of the performance art and culture
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• no.34
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• pp.9-42
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• 2017

Of all Geommu(劍舞, Korean sword dance), Gisaeng-Geommu danced by gisaeng(妓生, Korean female entertainers) for private guests and at the royal court. The Sword dance in the late Joseon Dynasty used to be dynamic exuding menacing "sword spirit(劍氣)." Sword dance being transmitted today is more ritualistic and elegant. This study considers Korean sword dance has a core structure and motifs transcending generational differences, and based on this critical thinking, aims to analyze the structure of Korean sword dance. This study analyzed the prose "Geommugi(劍舞記)" by Park Je-ga(朴齊家) and the poem "Mugeompyeonjeongmiin(舞劍篇贈美人)" by Jeong Yak-yong(丁若鏞) out of literary works from the late Joseon Dynasty, and from official records of rituals(笏記), "Geomgimu(Sword Dance, 劍器舞)" and "Geommu" in "Gyobanggayo(敎坊歌謠)." In the introduction part of Sword dance, a dancer appears, bows and performs a hand dance or hansam(汗衫) dance to and fro. In the development part, a dancer meets with a sword but first hesitates to hold it and dances holding swords in both hands. The climax shows expert sword skills and combat scenes. In the conclusion part, the court dance involves a dancer bidding a formal farewell, while the dance for entertainment, a dance throws away the sword to finish. From literature materials, the structure of Korean sword dance could be divided into an introduction, a development, a climax and a conclusion. Based on this, this study analyzed sword dance movements by linking the beats accompanying the current sword dance, in the order of a Yeombul, the traditional Korean ballad Taryeong or Neujeun Taryeong, Jajin Taryeong, Taryeong and Jajin Taryeong. The introduction part includes a Buddhist prayer and the beginning of Taryeong. Dancers appear, and in two rows they dance facing each other. On the slow beat, their dances are relaxed and elegant. The development part is matched with Jajin Taryeong. Dancers sit in front of swords and grab them, and they dance holding a pair of swords. The beat gradually becomes faster, progressing the development of the dance. But then, the slower Taryeong is placed again. The reason behind it is to create a tension for a little while, before effectively reaching a climax by speeding up the tempo again. Moving on to Jajin Taryeong, dancers' movements are bigger and more dynamic. The highly elated Jajin Taryeong shows dance movements at the climax on fast, robust beats. In the conclusion part, the beat is quick-tempo and on the upbeat again on Jajin Taryeong. Driving on without a stop on the exciting Yeonpungdae(燕風臺) melody, dancers standing in a line dance wielding the swords and bow before finishing.