• Title/Summary/Keyword: 18세기

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Host-Guest Interactions of Cyclic and Acyclic Polyethers with Alkylammonium Ions (고리 및 비고리 폴리에테르와 알킬암모늄 이온과의 호스트-게스트 상호작용)

  • Jeong, Jong Hwa;Kim, Dae Yeon;Lee, Sim Seong
    • Journal of the Korean Chemical Society
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    • v.38 no.7
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    • pp.509-515
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    • 1994
  • The interactions of 11 kinds of primary and secondary alkylammonium ions with cyclic (12C4, 15C5, 18C6, DT18C6 and DA18C6) and acyclic$(Q_2O_5)$ polyethers were investigated by NMR titration and conductometry. All of the alkylammonium ions under investigation form the relatively stable 1 : 1 complexes with crown ethers and acyclic polyether by H-bond. The interactions of alkylammonium ions with analogeous hosts having different size were in the order of 18C6 > 15C5 > 12C4, and the strengthes of donor atoms toward the alkylammonium ions were in the order of N > O > S. 18C6 forms more favorable interactions with primary alkylammonium ions than secondary alkylammonium ions, otherwise DA18C6 shows the opposite behaviors. The stability constants for complexations of 18C6 with the alkylammonium ions were determined conductometrically in methanol at 25$^{\circ}C$. The major factors affecting the stability of complexes were the type of alkylammonium ions, the length of alkyl-chain and the steric hindrance due to the structure of alkyl groups on complexation.

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A study on composition and narrative style of 『Jwagyebudam』 (『좌계부담(左溪裒談)』의 구성과 서술방식)

  • Cho, Jeongyun
    • (The)Study of the Eastern Classic
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    • no.63
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    • pp.83-113
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    • 2016
  • This paper is focused on objective and meaning of its compilation through reviewing system, composition, method of description, and content of "Jwagyebudam". "Jwagyebudam" has all round form of a history and character book by recording via arranging figures from the end of 16th century to the middle of 18th century in a chronological order. Figure were not only assigned at close range by steretyping people into groups to a degree in it, but also recorded in a chronological order. In view of method of description, "Jwagyebudam" concentrated a theme by recording via separating different people associated from a figure and content of the same event by using the same method like 'Hogeonbeom(互見法)' shown in "Sagiyeoljeon(史記列傳)". In addition, it obtained effect to objectify evaluation of figures included. In a method of embodying figures, it has described concretely and in a three dimensions figures by recording anecdotes and poems associated with them via focusing on lifelong characteristic aspect of corresponding figures. In other words, "Jwagyebudam" can be called by biographies or character books, writings specialized in characters center among writings of method to weave freely experience. In a broad sense, it can be called a writing to cover a function of history book, poem and picture. This was located to a starting point of variation of inclusive and descriptive method. Namely, several kinds of writings in late Joseon dynasty can show aspect to fulfill specialized aspect gradually.

고출력 펨토초 레이저와 플라즈마의 상호작용을 통한 극고속 X선 펄스의 발생

  • Jeong, Sang-Yeong;Hwang, Seok-Won;Lee, Hae-Jun
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.08a
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    • pp.38-38
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    • 2010
  • 낮은 세기의 레이저와 정지한 전자가 반응하면 전자는 레이저 전기장 세기에 비례하여 가속되며 레이저의 파장과 같은 파장의 빛을 낸다. 반면, 레이저의 세기가 일정 수준을 넘으면 전자의 속도가 빛의 속도에 가까워지게 되어 가속이 둔화되는 현상이 나타나며, 더 이상 전기장의 세기와 가속도가 비례하지 않게 된다. 이러한 비선형적인 전자의 운동이 레이저 기본 파장의 조화파(harmonic)를 발생시키는데, 이를 상대론적 비선형 톰슨 산란(relativistic nonlinear Thomson scattering, RNTS)이라고 한다. 단일 전자를 가정한 경우 RNTS에 의해 아토초($10^{-18}$ 초) 길이의 X선 펄스가 발생하는 것이 시뮬레이션 연구를 통해 잘 알려졌다. [1] 그러나, 실제 실험에서 적용할 수 있는 것은 단일 전자가 아니라 고체, 플라즈마, 전자 빔 등의 전자 덩어리이다. 전자덩어리를 구성하는 각각의 전자가 아토초 펄스를 발생시더라도 각각의 펄스 간에 결맞음(coherence) 조건이 맞지 않으면 아토초 펄스는 발생되지 않는다. 또한, 강한 세기의 펄스를 얻는데도 결맞음은 중요하다. 이 연구에서는 결맞음 조건으로 얇은 타깃에 대한 거울 반사 조건, 즉 레이저가 얇은 타깃에 입사되며 거울의 반사 조건을 만족하는 위치에 검출기(detector)를 위치시키는 방법을 제안하였다. 박막이 충분히 얇을 경우 각각의 전자에 대하여 레이저가 발사되어 타깃에 맞고 검출되기까지의 시간이 거의 일치하게 된다. 거울 반사 조건에 의한 아토초 펄스 발생은 particle-in-cell 방법을 통한 시뮬레이션으로 검증되었다. 결맞음 조건을 위한 얇은 타깃으로는 박막과 나노선 배열(nanowire array)을 사용하였다. 전자들 간의 쿨롱(Coulomb) 힘은 결맞음이 유지되는 것을 방해하는데, 박막에 비해 나노선 배열이 쿨롱 힘의 영향을 적게 받기 때문에 결맞음이 더 잘 유지된다.

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A Study on the Influence of 18th Century Costumes in Contemporary Fashion (메트로폴리탄 박물관의 18세기 복식전시가 현대 패션에 미친 영향 연구)

  • Yun, Un-Jae;Park, Hyung-Ai
    • Journal of the Korean Home Economics Association
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    • v.44 no.1 s.215
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    • pp.25-35
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    • 2006
  • This study investigated the scheme for correctly making Korean fashion design known to the world. It attempted to increase the influence of the Eighteenth Century Costume in contemporary fashion. During the 18th century, France had an almost complete monopoly of fashion. Growing out the fairyland atmosphere of the French Court and often conceived of as ennui by personal vanity, this fashion was a product of an age which sought at any price to live life with supreme grace. Most of the special costume exhibitions in the Metropolitan Museum of Art are planned and directed by Polaire Weissman, Diana Vreeland, Richard Martin, Harold Koda. The Costume Institute has held exhibitions of the Eighteenth Century Costume several times such as "Museum Period Rooms Re-Occupied in Style," "the Eighteenth Century Women," "the Ceaseless Century," "Dangerous Liaisons," etc. Especially, the exhibition of "Dangerous Liaisons" is organized in ten parts such as the Portrait, the Levee, the Music Lesson, the Withdrawing Room, the Broken Vase, the Favorite, the Masked Beauty, the Card Game, the Late Supper, and the Shop. Using the eighteenth century as its touchstone, The Ceaseless Century proceeds differently, not seeking the short distance between a discrete present and the multiple past but rather showing the complicated navigation that comes of revivalism swing to and fro on the timeline of history and sensibility. The designers featured include Karl Lagerfeld, Gianni Versace, Vivienne Westwood, Jean Paul Gaultier, Christian Dior, Cristobal Balencicga, Christian Lacroix, Stella McCartney forChloe, Olivier Theyskens, Alexander McQueen, etc. Therefore, Korean designers should refrain from (Ed-confirm) the foreign collection without a clear purpose and should devote their effort to create with an active attitude.

Reconstruction of May Precipitation (317 Years: AD. 1682~1998) using Tree Rings of Pinus densiflora S. et. Z. in Western Sorak Mt. (설악산 서부 소나무의 연륜을 이용한 317년 (A.D. 1682~1998)간의 5월 강수량 복원)

  • 서정욱;박원규
    • The Korean Journal of Quaternary Research
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    • v.16 no.1
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    • pp.29-36
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    • 2002
  • May rainfall (317 years: A.D. 1682~A.D. 1998) of western region of Sorak Mt. was reconstructed using a tree-ring chronology of Pinus densiflora 5. et 2. The reconstruction indicated that the 1690~1710년, 1745~1755 and 1847~1853 periods were the least May rainfalls, whereas 1715~1733 and 1835~1845 the greatest ones. The wet period of 1835~1845 was agreed with that found in Songni Mt., central Korea. This wet epoch seems to be widely spreaded in Korea. There were found no significant differences among the means of the 18th, 19th and 20th century's May rainfalls. The major periodicity of May rainfalls was 2~4 years.

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Target Localization Method using the Detection Signal Strength of Seismic Sensors for Surveillance Reconnaissance Sensor Network (감시정찰 센서 네트워크에서의 지진동센서 탐지 신호 세기를 이용한 표적 측위 방법)

  • Hyeon-Soo Im;In-Yong Hwang;Hyung-Seok Kim;Sang-Heon Shin
    • The Journal of the Korea institute of electronic communication sciences
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    • v.18 no.6
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    • pp.1291-1298
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    • 2023
  • Surveillance reconnaissance sensor network is used for surveillance in wartime and area of operation. In this paper, we propose a target localization method using the detection signal strength of seismic sensors. Relay equipment calculates the target location using coordinate information and detection signal strength of the seismic sensors. Target localization error deviation due to environmental factors was minimized by subtracting the dynamic offset when calculating the target location. Field test shows improvement of target localization through reduction of errors. The average error was decreased to 3.62m. Up to 62% improved result was obtained compared to weighted centroid localization method.

A Study on Glass Mirror Trade and its Characteristics of Craft after Joseon Dynasty (조선 후기 유리거울의 수입과 공예품의 특징)

  • Park, Jinkyung
    • Korean Journal of Heritage: History & Science
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    • v.52 no.4
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    • pp.206-225
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    • 2019
  • This paper examines the trade and development aspects of glass mirrors through the literature records of the Joseon Dynasty, and studies the characteristics of existing glass mirror crafts by referring to the terms and types shown in the literature. The glass mirror in the records had called western mirrors(西洋鏡, 洋鏡), glass mirrors(玻璃鏡, 玻瓈鏡), stone mirrors(石鏡), etc. Glass mirrors were imported mainly through trade with Russia and the Qing Dynasty since the 17th century and were banned from importation in the late Joseon Dynasty. These mirrors were something new that caused a great stirring in Joseon society in the 18th century, and in the 19th century, it grew larger as a commodity needed for everyday life, especially with trade with Japan. At that time, glass mirrors were used for various purposes, such as installing large glass at a store, which were not the standard mirror usage of confirming one's appearance. These mirrors surprised Koreans in Joseon who experienced them at Yanjing Liulichang(燕京 琉璃廠) in the 18th and 19th centuries. As a result, the demand for glass mirrors rapidly increased and quickly surpassed that of bronze mirrors. Consequentially, new crafts using glass mirrors instead of bronze mirrors in Joseon began to be produced and used after the 18th century. In particular, integrated flat boards of glass mirrors were developed as crafts used indoors. It was convenient to use the hair comb box, a long-time presence in Joseon society, with the bronze mirror. This kind of mirror remained apparent in various genre paintings, including the Taepyeong Seongsido(太平城市圖, 'A Thriving City in a Peaceful Era') collected the National Museum of Korea which reflect its populism of the times. Also, the Mirror Stand(鏡臺) used in the Qing Period was produced in Joseon, but there was a difference in the way of making the drawers and box shapes between two nations. On the other hand, the Face Mirror(面鏡) was made to look at the face. Various crafts made with the aesthetic sense of Joseon, such as the ox horn inlaying craft technique, were produced with auspicious designs. In the 19th century, glass mirrors were imported from European countries, such as France, Denmark, the Netherlands, and the United Kingdom, however after the end of the 19th century Japanese crafts were popular. Glass mirrors, which were popular in the Meiji and Taisho eras of Japan, were imported and also the Mirror Screen(鏡屛) using large glass mirrors were used. In particular, the mirror screen had developed wood furniture since the previous time, which were used for banquets and large spaces, such as the drawing room, and were imported from China and Japan. In addition, the western architectural effect of attaching a mirror to the wall was also attempted to adjust the brightness of the space and introduce another image and scenery in the mirror. This was done at Deoksugung Palace's Seokjojeon.

생체모방 근육형 작동기 개발 및 응용

  • 윤광준;박훈철;구남서;배영민
    • Journal of the KSME
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    • v.44 no.6
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    • pp.40-47
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    • 2004
  • 18세기 일어난 산업혁명은 중세 농업국가에서 근대 산업국가로 탈바꿈하는 계기가 되었다 이러한 역사적 사건이 일어나게 된 초석은 바로 증기기관의 발명이다. 이후 산업화의 발자취를 살펴보면 새로운 동력 변환 장치가 개발될 때마다 사회경제적인 변화가 발생하고 새로운 패러다임을 가진 세상이 열리게 됨을 알 수 있다. 21세기에 출현하리라고 많은 사람들이 기대하고 있는 것 중 하나가 바로 인간형 또는 생체 모방형 로봇이다. (중략)

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뉴스의 인물1-제2대 광주과학기술원장 김효근박사

  • Kim, Hyo-Geun
    • The Science & Technology
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    • v.31 no.3 s.346
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    • pp.18-19
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    • 1998
  • 21세기의 우수과학기술 인재를 양성한다는 목표아래 지난95년 개원한 광주과학기술원은 세계적인 연구중심대학원으로 정보통신공학 등 5개학과를 개설하고 있다. 지난해 11월 제2데 원장으로 취임한 김효근 박사는 "21세기 정보화 국제화 시대에 대비하기 위하여 유엔대학 부설연구소를 유치하고 세계의 우수대학과 인적교류 및 공동연구로 광주과기원 발전에 최선을 다하겠다."고 밝히고 있다.

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