• 제목/요약/키워드: STAR

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STAR-CCM+를 이용한 썬루프 버페팅 유동 소음 해석 (Numerical Analysis of Sunroof Buffeting using STAR-CCM+)

  • 사티쉬 본투;프레드 멘돈카;김귀연;백영렬
    • 한국소음진동공학회논문집
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    • 제24권3호
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    • pp.213-218
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    • 2014
  • 썬루프 버페팅 소음의 고유특성을 의미하는 속도에 따른 소음강도의 증-감쇠 현상을 살펴보고자, HSM(Hyundai simplified model) 형상에 대해서 유동소음 해석 프로그램인 STAR-CCM+을 통하여 전체 차속 범위에 걸쳐 시험과 비교 검토하였다. 차량 내부의 재질에 따른 압축성 효과 및 감쇠효과는 인공 압축성과 감쇠 보정 기법인 FRET(frequency response test)를 이용하였다. 시뮬레이션 결과는 특정 속도에서 나타나는 소음 강도의 증-감쇠 시험결과를 매우 잘 예측하였으며 최대 SPL 수치도 정확히 예측하였다. 이는 썬루프 개방에 의해 발생하는 전단면에서의 유동 박리 주파수를 유동 소음 해석인 STAR-CCM+가 전 차속에 걸쳐서 매우 잘 예측하고 있음을 나타낸다.

The effect of young stellar populations in Early-type galaxies

  • 서혜원;정현진;오규석;이석영
    • 천문학회보
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    • 제35권1호
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    • pp.74.1-74.1
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    • 2010
  • We have investigated the radial g-r color gradients of early-type galaxies in the Sloan Digital Sky Survey (SDSS) DR6 in the redshift range 0.00$H{\beta}$ absorption-line strengths and/or emission-line ratios that are indicative of the presence of young stellar populations. This implies that most of the residual star formation in early-type galaxies is centrally concentrated. Blue-cored galaxies are predominantly low-velocity dispersion systems. A simple model shows that the observed positive color gradients are visible only for a billion years after a star formation episode for the typical strength of recent star formation. The observed effective radius decreases and the mean surface brightness increases due to this centrally concentrated star formation episode. As a result, the majority of blue-cored galaxies may lie on different regions in the fundamental plane (FP) from red-cored ellipticals. However, the position of the blue-cored galaxies on the FP cannot be solely attributed to recent star formation but requires substantially lower velocity dispersion. We conclude that a low-level of residual star formation persists at the centers of most of low-mass early-type galaxies, whereas massive ones are mostly quiescent systems with metallicity-driven red cores.

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NO EXCESS OF STAR FORMATION IN THE z = 1.4 STRUCTURE: Hα OBSERVATIONS OF THE RADIO-LOUD AGN 6CE1100+3505 FIELD

  • Shim, Hyunjin;Lee, Jong Chul;Hwang, Narae;Park, Byeong-Gon
    • 천문학회지
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    • 제52권6호
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    • pp.235-244
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    • 2019
  • We present the results of near-infrared imaging observations of the galaxy overdensity around the z = 1.44 radio-loud active galactic nucleus (AGN) 6CE1100+3505, which was carried out with the purpose of sampling the redshifted Hα emission from the actively star-forming galaxies that could constitute the overdensity. The existence of the structure around this AGN was spectroscopically confirmed by previous grism observations which are however limited to the central region. Using the CH4Off narrow/medium-band and H broad band filters in the Wide Infrared Camera (WIRCam) on the Canada-France-Hawaii Telescope (CFHT), we constructed a sample of objects that show a flux excess in the CH4Off band due to line emission. The emission line flux is ~ 4.9 × 10-16 erg s-1 cm-2, corresponding to a star formation rate (SFR) of ~ 50 M yr-1 for galaxies at redshifts z ~ 1.4. None of the galaxies with medium-band flux excess is located within 1 Mpc from the central AGN, and there is no evidence that the selected galaxies are associated with the proposed cluster. Along with the star formation quenching near the center that was found from the previous grism observations, the lack of extreme starbursts in the structure suggests that at z ~ 1.4, overdense regions are no longer favorable locations for vigorous star formation.

1960년대 록 스타 패션의 도상학적 해석 (Iconological Interpretation of the Fashion of Rock Stars in the 1960's)

  • 이정원;금기숙
    • 복식
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    • 제58권6호
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    • pp.69-84
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    • 2008
  • Considering that star reflects the image of current society, analyzing fashion of celebrity is to read ideal type and demands of beauty of the era. Especially the rock music-represents youth culture that last on present day-born in 1960's, and it is considered to a significant decade in pop music history. Thus this research will analysis rock star's fashions in iconological view of E. Panofsky. The aim of this document is Clarifying how the fashion of pop stars appeared and what formed its worth. As a result of analyzing fashions of rock star in 1960's, it is available to find these sameness and difference. The Mods borrowed images of the past, and introduce the elite modernism and shows very urban style. The Folky and the Psychedelic showed post-structuralism propensity against industrial society, in the case of the Folky it induced styles that symbolize labor class to realize social worth. And as an aftereffect of war and repulsion of commercial worth, they embody nature-returning peasant look so that it shows pastoral mood in total. The Psychedelic express somewhat struggling escapism and it generated illusionary images with quests to superego and glorification to psychedelic status. The Folky and the Psychedelic are same in the side of introducing existentialism, this occurred by using ethnic factor. But the Folky showed plain outlook by pop propensity, on the other hand, the Psychedelic showed magnificent outlook such as optical art, pop art, and futurism ought to express merrymaking culture. And common feature of these is introduction of unisex mod which is came after the change of gender role. Thus each star or group has professed special ideology into their culture and it is reflected to acts which is including music and dress style. This affair is analyzed like these two things. The mass of people schemes their identity with inducing special ideology to their culture at the first. And the purpose to archive cultural hegemony in inter-social class at the next.

한국어 양순 파열음 발음시 구강내압과 폐쇄기, VOT에 대한 연구 (The Study on Intraoral Pressure, Closure Duration and VOT During Phonation of Korean Bilabial Stop Consonants)

  • 표화영;최홍식
    • 대한후두음성언어의학회지
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    • 제7권1호
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    • pp.50-55
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    • 1996
  • Acoustic analysis study was performed on 20 normal subjects by speaking nonsense syllables composed of Korean bilabial stops$(/P, P^{\star}, P^{h}/)$ and their preceding and/or following vowel /a/ (that is, $[pa, p^{\star}a, p^{h}a, apa, ap^{\star}a, ap^{h}a]$) with an ultraminiature pressure, sensor. in their mouths. Speech materials were phonated twice, once with a moderate voice, another time with a loud voice. The acoustic signal and intraoral pressure were recorded simultaneously on computer. By these procedures, we were to measure the intraoral pressure, closure duration and VOT of Korean bilabial stops, and to compare the values one another according to the intensity of phonation and the position of the target consonants. Intraoral pressure was measured by the peak intraoral pressure value of Its wave closure duration by the time interval between the onset of intraoral pressure build-up and the burst meaning the release of closure ; Voice onset time(VOT) on by the time interval between the burst and the onset or glottal vibration. Heavily aspirated bilabial stop consonant /$p^h$/ showed the highest intraoral pressure value, unaspirated /$p^{\star}$/, the second, slightly aspirated /P/, the lowest. The syllable initial bilabial stops showed higher intraoral pressure than word initial stops, and the value of loudly phonated consonants were higher than moderate consonants. The longest closure duration period was that of /$p^{\star}$/ and the shortest, /P/, and the duration was longer in word initial position and in the moderate voice. In VOT, the order of the longest to shortest was $/{p^h}/, /p/, /{p^\star}/$, and the value was shorer when the consonant was in intervocalic position and when it was phonated with a loud voice.

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고출력 LED 패키지의 열 전달 개선을 위한 금속-실리콘 병렬 접합 구조의 특성 분석 (Heat Conduction Analysis of Metal Hybrid Die Adhesive Structure for High Power LED Package)

  • 임해동;최봉만;이동진;이승걸;박세근;오범환
    • 한국광학회지
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    • 제24권6호
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    • pp.342-346
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    • 2013
  • 고출력 LED 패키지의 방열 특성 향상을 위하여, 다이 접합부에 실리콘 접착제와 금속 패턴의 병렬 접합 구조를 적용하여 열 유동 해석을 수행하였다. 그 결과, LED 칩에서 발생한 열은 주로 금속 패턴 구조물을 통해 기판으로 효과적으로 전달되고 있으나, 패턴 구조물의 크기에 따라 효율의 차이가 있음을 확인하였고, 그 효과를 정량화하기 위해 정규화 길이를 도입하여 칩과 금속 패턴 구조물의 면적에 따른 열 저항을 비교하였다. 정규화 길이가 길어지면 금속 패턴 구조물에 의한 열 우회 경로가 칩에 고르게 분포하여 열 저항이 감소하였으며, 그 값은 단순 병렬 열 저항 이론 값보다 다소 큰 수치로 수렴하지만, 충분한 열 저항 개선 효과를 얻을 수 있었다.

THE NEW ECLIPSING POST COMMON-ENVELOPE BINARY SDSS J074548.63+263123.4

  • HEMHA, NIWAT;SANGUANSAK, NUANWAN;IRAWATI, PUJI;DHILLON, VIK;MARSH, TOM R.
    • 천문학논총
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    • 제30권2호
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    • pp.201-204
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    • 2015
  • The common-envelope process is a complicated phase in binary evolution. A lot of effort has been dedicated to study the common-envelope stage, but many questions related to this process are yet to be answered. If one member of the binary survives the common-envelope phase, the binary will emerge as a white dwarf accompanied by a low-mass main sequence star in close orbit, often referred as a post common-envelope binary (PCEB). SDSS J0745+2631 is among the list of newly found PCEBs from the Sloan Digital Sky Survey (SDSS). This star is proposed to be a strong eclipsing system candidate due to the ellipsoidal modulation in its light curve. In this work, we aim to confirm the eclipsing nature of SDSS J0745+2631 and to determine the stellar and orbital parameters using the software Binary Maker 3.0 (BM3.0). We detected the primary eclipse in the light curve of SDSS J0745+2631 in our follow-up observation from January 2014 using the ULTRASPEC instrument at the Thai National Observatory. The data obtained on 7th and 8th January 2014 in g filter show an evident drop in brightness during the eclipse of the white dwarf, but this eclipse is less prominent in the data taken on the next night using a clear filter. According to our preliminary model, we find that SDSS J0745+2631 hosts a rather hot white dwarf with an effective temperature of 11500K. The companion star is a red dwarf star with a temperature of 3800K and radius of 0.3100 $R_{\odot}$. The red dwarf star almost fills its Roche lobe, causing a large ellipsoidal modulation. The mass ratio of the binary given by the Binary Maker 3.0 (BM3.0) model is M2/M1 = 0.33.

De-epithelialized dermal flap for nipple reconstruction: A modified star flap

  • Lee, Su Hyun;Kim, Deok Woo;You, Hi Jin;Jung, Jae A;Hwang, Na Hyun;You, Jae Pil;Yoon, Eul Sik
    • Archives of Plastic Surgery
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    • 제46권4호
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    • pp.324-329
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    • 2019
  • Background Multiple approaches for nipple reconstruction exist, and none is considered superior to all others. The star flap is one of the most popular methods for nipple reconstruction, but gradual height loss is a major concern. We present a new modification of the star flap that incorporates a de-epithelialized dermal flap, along with the associated surgical results. Methods We reviewed the medical records of patients who underwent nipple reconstruction using the modified star flap method. The design was different from the conventional star flap in that the lateral wings were changed into a trapezoidal shape and de-epithelialized dermal flaps were added. The patients were followed up at 2, 4, 6, and 12 months postoperatively, and nipple height was measured. The postoperative nipple height achieved using the modified method was compared with that obtained using the traditional method. Results From February 2013 to June 2017, 32 patients received surgery using the modified star flap, and 18 patients who underwent nipple reconstruction before 2013 comprised the conventional method group. All patients had undergone breast reconstruction with an abdominal tissue-based flap. The mean follow-up period was 14.4 months in the modified method group and 17.3 months in the conventional method group. The mean maintenance of projection at 12 months postoperatively was $56.28%{\pm}18.58%$ in the modified method group, and $44.23%{\pm}14.15%$ in the conventional method group. This difference was statistically significant (P<0.05). Conclusions The modified method using a de-epithelialized dermal flap provides reliable maintenance of projection in patients who have undergone abdominal tissue-based breast reconstruction.

축구 스타의 휴먼 브랜드가 구단에 대한 태도 및 애착에 미치는 영향 (The Impact of Soccer Star's Human Brand on Attitude and Attachment to club)

  • 신진호
    • 한국응용과학기술학회지
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    • 제38권2호
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    • pp.579-586
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    • 2021
  • 본 연구는 축구 스타의 휴먼 브랜드가 구단에 대한 태도 및 애착에 미치는 영향력을 규명하여 구단 소속 스타 선수들의 브랜드 관리의 중요성 및 시사점을 제공하고자 했다. 따라서 K리그 구단 소속 축구 선수를 선호하고 있는 사람을 표본으로 선정해 2021년 1월 14일부터 3월 5일까지 모바일 조사를 실시했으며, 총 348부의 자료를 최종 분석에 이용했다. 자료처리는 SPSS(ver. 21.0) 프로그램을 활용해 빈도분석, 내적일관성 및 탐색적 요인분석, 상관분석, 다중회귀 분석을 실시했다. 본 연구의 주요 결과는 다음과 같다. 첫째, 축구 스타의 휴먼 브랜드는 윤리성, 매력성, 차별성 순으로 구단에 대한 태도에 영향을 미치는 것으로 나타났다. 둘째, 축구 스타의 휴먼 브랜드는 윤리성, 매력성, 차별성 순으로 구단에 대한 애착에 영향을 미치는 것으로 나타났다.

TRAO-TIMES: Investigating Turbulence and Chemistry in Two Star-forming Molecular clouds

  • Yun, Hyeong-Sik;Lee, Jeong-Eun;Choi, Yunhee;Evans, Neal J. II;Offner, Stella S.R.;Baek, Giseon;Lee, Yong-Hee;Choi, Minho;Kang, Hyunwoo;Cho, Jungyeon;Lee, Seokho;Tatematsu, Ken'ichi;Heyer, Mark H.;Gaches, Brandt A.L.;Yang, Yao-Lun
    • 천문학회보
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    • 제46권2호
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    • pp.37.2-37.2
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    • 2021
  • Turbulence produces the density and velocity fluctuations in molecular clouds, and dense regions within the density fluctuation are the birthplace of stars. Also, turbulence can produce non-thermal pressure against gravity. Thus, turbulence plays a crucial roles in controlling star formation. However, despite many years of study, the detailed relation between turbulence and star formation remain poorly understood. As part of the Taeduk Radio Astronomy Observatory (TRAO) Key Science Program (KSP), "mapping Turbulent properties In star-forming MolEcular clouds down to the Sonic scale (TIMES; PI: Jeong-Eun Lee)", we mapped two star-forming molecular clouds, the Orion A and the ρ Ophiuchus molecular clouds, in six molecular lines (13CO 1-0/C18O 1-0, HCN 1-0/HCO+ 1-0, and CS 2-1/N2H+ 1-0) using the TRAO 14-m telescope. We applied the Principal Component Analysis (PCA) to the observed data in two different ways. The first method is analyzing the variation of line intensities in velocity space to evaluate the velocity power spectrum of underlying turbulence. We investigated the relation between the star formation activities and properties of turbulence. The other method is analyzing the variation of the integrated intensities between the molecular lines to find the characteristic correlation between them. We found that the HCN, HCO+, and CS lines well correlate with each other in the integral shaped filament in the Orion A cloud, while the HCO+ line is anti-correlate with the HCN and CS lines in L1688 of the Ophiuchus cloud.

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