• Title/Summary/Keyword: retro

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Efficient Cyclization of Substituted Diphenols : Application to the Synthesis of Sulforhodamine B (치환 다이페놀의 효율적 고리화 반응: 설퍼로다민B의 합성에의 응용)

  • Park, Min Kyun;Shim, Jae Jin;Ra, Choon Sup
    • Clean Technology
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    • v.21 no.2
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    • pp.102-107
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    • 2015
  • Rhodamine dyes are widely used as fluorescent probes because of their excellent photophysical properties, such as high extinction coefficients, excellent quantum yields, great photostability, relatively long emission wavelengths. A great synthetic effort has been focused on developing efficient and practical procedures to prepare rhodamine derivatives, because for most applications the probe must be covalently linked to another (bio)molecule or surface. Sulforhodamine B is one of the most used rhodamine dyes for this purpose, because it carries two sulfoxy functions which can be easily utilized for binding with other molecules. Recently, we needed an expedient, practical synthesis of sulforhodamine derivatives. We found the existing procedure for obtaining those compounds unsatisfactory, particularly, with the cyclization process of the dihydroxytriarylmethane (1) to produce the corresponding xanthene derivative (2). We report here our findings, which represent modification of the existing literature procedure and provide access to the corresponding xanthene derivative (2) in a high yield. Use of methanol as a co-solvent was found quite effective to prohibit the water molecule produced during the cyclization reaction from retro-cyclizing back to the starting dihydroxytriarylmethane and the yield of the cyclization was increased (up to 84% from less than 20%). The reaction temperature was significantly lowered (80 vs. 135 ℃). Thus, the reaction proceeds in a higher yield and energy-saving manner where the use of reactants and the production of chemical wastes is minimized.

A Study on the Cadmium Tolerance of Some Native Herb Plants (수종 야초류의 카드뮴 내성에 대한 연구)

  • Chang, Ju-Youn;Chang, Yun-Young;Bae, Bum-Han;Lee, In-Sook
    • The Korean Journal of Ecology
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    • v.24 no.5
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    • pp.309-313
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    • 2001
  • This research was conducted to test cadmium tolerance by five speices of native herbs for screening cadmium tolerance plant. We examined germination rate, root and shoot growth rate of seedling, fresh biomass of native herbs exposed to cadmium solution for 14 days. Especially, germination rate of Abutilon avicennae and Amaranthus retroflexus was over 90% in all concentration, but germination rate of Aeschynomene indica, Echinochloa crus-galli var. oryzicola and Echinochla crus-galli var. frumentacea began to decrease when they exposed to 15 mgCdSO₄ /L. The higher the Cd concentration, the length of root, shoot grew lower. The fresh biomass of Echinochloa crus-galli var. oryzicola, Echinochla crus-galli var. frumentacea and Amaranthus retro-flexus were not so different from each control, but those of Abutilon avicennae and Aeschynomene indica began to decrese greatly when exposed to 60 mgCdSO₄ /L. EC/sub 50/(Effective Concentration 50%) of Abutilon avicennae, Aeschynomene indica and Amaranthus retroflexus was 44.6∼77.5 mgCdSO₄ /L for root growth, 38.6∼114 mgCdSO₄ /L for shoot growth, 60∼107.5 mgCdSO₄ /L for fresh biomass. Among the native herbs, sensitivity of cadmium ordered as root length > fresh biomass > shoot length. These results indicate that Abutilon avicennae is a tolerant species for cadmium.

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A Study of the sustainable Design Direction for a City Commuter Vehicle (씨티 커뮤터 자동차를 위한 지속 가능한 디자인 방향에 관한 연구)

  • 조원철
    • Archives of design research
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    • v.13 no.3
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    • pp.59-68
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    • 2000
  • This thesis is about design spirit demanded by the 21st century vehicle design studied in consideration of city commuter. First of all, going over the transition of the last century vehicle design led to the arrangement of the changes in vehicle models. Even though the invention of vehicles brought about immense improvement in living standard of the people, it also brought about other factors that were harmful for human living. Through this realization the main fact that should be emphasized is that the vehicles in 21s1 century should not be a threat to the human life or be the main cause for the environmental pollution of the earth. With the question as to whether the vehicles development direction at the beginning of the year 2000 like the Retro design and Hybrid-Compact car development is appropriate to these demands, the development of City Commuter vehicle (the most human and environment-friendly concept which can also serve as the connecting means in transportation system) and its case studies were compared. Through this, the design spirit that should be inherent in environment and vehicle human and vehicle relationships and the design factors needed for the continuous development of the vehicles were arranged.(classified) Rather than suggesting a new direction for the specific style for vehicle design, this thesis is to emphasize that to improve the standard living of the people with vehicle as a product that will be continually produced in the 21st century, the morals and the mission of the designers about the environment and humanity recovery should be the core of the active movement and education of vehicle design.

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Minimalism in Modern Hairstyle and Fashion (현대 헤어스타일과 의상에 나타난 미니멀리즘의 양상)

  • Sohn Hyang-Mi;Park Kil-Soon
    • Journal of the Korean Society of Clothing and Textiles
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    • v.29 no.12 s.148
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    • pp.1554-1561
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    • 2005
  • This study aims to analyze modern hairstyle and fashion in the collections in the late 1990s, based on the concepts and characteristics of Minimalism, a buzzword of the art field in the 1960s. This study used qualitative research method, in other words, presenting an analysis framework by studying domestic and foreign books and dissertations on Minimalism and then applying the Internet or visual image to the analysis framework. The result indicates that Minimalism design in modem hairstyle and fashion has four characteristics: simplicity, unity, repetition and spatiality.

Space Debris Tracking Coverage Analysis of Spinning Disk for Optical Path Switch of Geochang Laser Tracking System (거창 레이저 추적 시스템의 광 경로 전환을 위한 회전 디스크의 우주쓰레기 레이저 추적 성능 분석)

  • Sung, Ki-Pyoung;Lim, Hyung-Chul;Yu, Sung-Yeol;Choi, Man-Soo;Ryou, Jae-Cheol
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.48 no.5
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    • pp.391-399
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    • 2020
  • KASI (Korea Astronomy and Space Science Institute) has been developing the multipurpose laser tracking system with three functions of satellite laser tracking, adaptive optics and space debris laser tracking for scientific research and national space missions. The space debris laser tracking system provides the distance to space debris without a laser retro-reflector array by using a high power pulse laser, which employs a spinning disk to change the optical path between the transmit and receive beams. The spinning disk causes the collision band which is unable to reflect the returned signal to a detector and then has an effect on the tracking coverage of space debris. This study proposed the mathematical model for tracking coverage by taking into account the various specifications of spinning disk such as disk size, spinning velocity and collision rate between the disk and hole. In addition, the spinning disk specifications were analyzed in terms of tracking coverage and collision band based on the mathematical model to investigate tracking requirements of the Geochang laser tracking system.

Development and Preliminary Performance Analysis of a fast and high precision Tracking Mount for 1m Satellite Laser Ranging (1m급 인공위성 레이저추적 시스템용 고속·고정밀 추적마운트 개발 및 예비 성능분석)

  • Choi, Man-Soo;Lim, Hyung-Chul;Lee, Sang-Jung
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.44 no.11
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    • pp.1006-1015
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    • 2016
  • This paper presents preliminary design and performance analysis of a fast and high precision Tracking Mount for 1m Satellite Laser Ranging(SLR) which is development by Korea Astronomy and Space science Institute(KASI). SLR is considered to be the most accurate technique currently available for the precise orbit determination of Earth satellites. The SLR technique measures the time of flight between pulses emitted from laser transmitter and pulses returned from satellites with laser retro-reflector array. It provides millimeter level precision of range measurements between SLR stations and satellites. A fast and high precision Tracking Mount for SLR which is proposed in this research should be capable of day and nighttime laser tracking about the satellites with laser reflectors from 200 km to 36,000 km altitude(geosynchronous orbit). In order to meet this requirement, we performed mechanical design and structural analysis for Tracking Mount. Also we designed the motion control system and conducted pre-performance analysis to obtain good performance results for a fast and high precision Tracking Mount.

Performance Analysis of the First Korean Satellite Laser Ranging System

  • Choi, Man-Soo;Lim, Hyung-Chul;Choi, Eun-Jung;Park, Eunseo;Yu, Sung-Yeol;Bang, Seong-Cheol;Kim, Tae-Keun;Kim, Young-Rok;Kim, Dong-Jin;Seong, Kipyung;Ka, Neung-Hyun;Choi, Cer-Hee;Hwang, Joo-Yeon;Kucharski, Daniel;Han, In-Woo;Nah, Jakyoung;Jang, Jung-Guen;Jang, Bi-Ho;Lee, Sang-Jung
    • Journal of Astronomy and Space Sciences
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    • v.31 no.3
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    • pp.225-233
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    • 2014
  • The first Korean satellite laser ranging (SLR) system, Daedeok SLR station (DAEK station) was developed by Korea Astronomy and Space Science Institute (KASI) in 2012, whose main objectives are space geodesy researches. In consequence, Korea became the $25^{th}$ country that operates SLR system supplementing the international laser tracking network. The DAEK station is designed to be capable of 2 kHz laser ranging with precision of a few mm both in daytime and nighttime observation of satellites with laser retro-reflector array (LRA) up to the altitude of 25,000 km. In this study, characteristics and specifications of DAEK station are investigated and its data quality is evaluated and compared with International Laser Ranging Service (ILRS) stations in terms of single-shot ranging precision. The analysis results demonstrated that the DAEK station shows good ranging performance to a few mm precision. Currently, the DAEK station is under normal operations at KASI headquarters, however, it will be moved to Sejong city in 2014 to function as a fundamental station for space geodesy researches in combination with other space geodesy systems (GNSS, VLBI, DORIS, etc.).

A Study on the Patterns of Recollection and the Desires of Users in the Drama Series (드라마 <응답하라> 시리즈의 기억 회상과 시청자의 수용욕망 연구)

  • Ahn, Sang-Won;Kim, Hye-Bin
    • The Journal of the Korea Contents Association
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    • v.16 no.9
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    • pp.679-693
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    • 2016
  • The purposes of this study were to examine the patterns of recalling memories in the series and look into the desires of viewers disclosed in the process. Entering the 2010s, people got to recall their memories from the 1980s and 1990s. Nostalgia and retro became cultural products. What made the series, those depict the pure love, friendship, and family affection of main characters under age in those decades, so popular among the viewers? Finding a repeating pattern in recollection of the past, dating, and family love, the investigator saw that the pattern met the needs of viewers and thus analyzed their desires inherent in the series with a focus on its "narratives" and "characters." Their unique sounds effect and music established a micro-narrative that could be divided, thus allowing viewers to own certain scenes easily, which worked to make "non-existent" memories. Secondly, the series succeeded in capturing the desire of viewers living in the age of neoliberalism to reduce their fatigue from excessive choices by setting the characters in a contrived way and thus presenting the desire of maintaining the stable middle class world with no conflicts and the passive female characters. The recollections provided by the series, in the end, fill the desire and deficiency of the present beyond a simple return to the past.

A Case Study of Tkatchev stretched Motion by Technical Feedback in Horizontal Bars (기술처치에 의한 철봉 Tkatchev stretched 동작의 사례연구)

  • Back, Jin-Ho;Son, Won-Il
    • Korean Journal of Applied Biomechanics
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    • v.18 no.4
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    • pp.77-87
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    • 2008
  • This study is to formulate strategy for subject who are selected as national team in horizontal bars event in apparatus gymnastics. For this, skill training program was applied to players for 8 weeks. Then it was analyzed by using 3D motion Analysis system to seek the difference between before and after using the program. There were decisive demerit element K's first try for Tkatchev stretched movement from low elevation and crooked body while elevating. Not only, the location of his center of mass is far and low and there was some concern in his landing due to bended his hip-joint, but also, it exposed weak point in retro-action followed technique. Thus, to overcome that weak point, the subject repeated practices on following; when preparing for Tkatchev stretched movement at downward for big spin, make sure extend shoulder angle faster, make sure Tap movement is short and concise using hip-joint angular while delaying Tap timing for folding the body, and moreover, while backlashing the body, used shoulder joint angle wide to pull up the body. As a result, the speed of vertical upward did rut increase when separation from the bar. However, height of elevation increased that the leg would rut hit the horizontal bar even straight up the hip-joint. Therefore, the movement itself provided magnificent motion and even helped decrease the demerits.

An Analysis on Retro Jacket Designs of Haute Couture Designers for the Development of High-Value Added Fashion Products (고부가가치 패션제품개발을 위한 오뜨꾸뛰르 디자이너 복고적 재킷디자인 분석)

  • Kim, Eonjeong;Yoo, Youngsun
    • Journal of the Korean Society of Costume
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    • v.64 no.3
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    • pp.77-92
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    • 2014
  • The purpose of this research is to examine the expression methods of Haute Couture designers' high value-added jacket designs, In order to achieve this, the positions and sizes of the design component items of tailored jackets designed by Haute Couture designers from the 1940s to the 1970s were analyzed. The results of the analysis are as follows. First, the silhouette changed while leading the contemporaneous fashions, and such changes could be confirmed by the width and length of the jacket's shoulder, chest, waist, and hem that determine the silhouette. Particularly, the length of the chest changed which signifies that the depth of the armhole was playing an important role in the production of high value-added jackets in relation to the sleeves and the fit of jackets. Second, the position and the size of the dart are the components that can express the fit of a jacket and the designer's creativity, The starting point position of the dart and the position passing by waist, and the position of the end of the dart were placed in the position beyond B.P. depending on the designer's creativity and techniques, deriving the changes of the silhouette and creating high value-added jackets. Third, the tailored collar, which was a three-dimensional component made up of the upper collar, gorge line, lapel, and break line, was an important component that could express high value-added jackets. Changes in the width and the height of the break line position of the sides of the neck were represented as changes in the neck size of the collar, and changes in the vertex locations of the upper collar corner-point, the gorge line (the corner-point of the lapel and V zone) were also represented as diverse tailored collar designs. And the differences in the width and the length of each component of the collar were related to each other and represented as changes in the slope and angle of the collar outline. Fourth, the changes in sleeve designs of the jacket were in such items as the width of the sleeve opening, the width of the sleeve hem, and the length of the sleeve, and were represented as diverse sleeve designs such as widened sleeve opening types, and straight line types.