• 한국재료학회지
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• 제19권7호
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• pp.376-381
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• 2009

Indium Tin Oxide (ITO) thin films on Polyethylene Terephtalate (PET) substrate were prepared by Roll-to-Roll sputter system with targets of 5 wt% and 10 wt% $SnO_2$ at room temperature. The influence of the chromaticity (b*) and transmittance properties of the ITO Films were investigated. The ITO thin films were deposited as a function of the DC power, rolling speed, and Ar/$O_2$ gas flow ratio, and then characterized by spectrophotometer. Their crystallinity and surface resistance were also analyzed by X-ray diffractometer and 4-point probe. As a result, the chromaticity (b*) and transmittance of the ITO films were broadly dependent on the thickness, which was controlled by the rolling speed. When the ITO films were prepared with the DC power of 300 W and the Ar/$O_2$ gas flow ratio of 30/1 sccm using 10 wt% $SnO_2$ target as a function of the rolling speeds 0.01 through 0.10 m/min, its chromaticity (b*) and transmittance were about -4.01 to 11.28 and 75.76 to 86.60%, respectively. In addition, when the ITO films were deposited with the DC power of 400W and the Ar/$O_2$ gas flow ratio of 30/2 sccm used in 5 wt% $SnO_2$ target, its chromaticity (b*) and transmittance were about -2.98 to 14.22 and 74.29 to 88.52%, respectively.

• 한국도서관정보학회지
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• 제52권2호
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• pp.401-428
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• 2021

최근 도서관에서는 다양한 SNS를 활용하여 이용자와의 소통을 시도하고 있다. 이중 인스타그램은 최근 이용자들이 가장 많이 사용하고 있는 SNS이다. 이에 본 연구에서는 국내에서의 도서관 인스타그램을 활성화하기 위해 도서관에서의 인스타그램은 어떻게 운영되고 있는지, 사람들은 어떤 게시물과 내용에 관심이 있는지, 도서관에서 어떻게 활용을 할 수 있는지에 대한 연구질문을 바탕으로, 현재 국내 도서관 인스타그램 운영의 개선방안 및 활성화 방안을 제시하고자 하였다. 이를 위해 먼저 SNS와 인스타그램의 이론적 배경 조사, 선행연구 분석 및 관련 자료를 수집하고 분석하였다. 다음으로 인스타그램에 개설된 국내 도서관의 계정 82개를 대상으로 도서관의 관종, 지역과 인스타그램 계정의 게시물 수, '팔로워' 수, '팔로우' 수, 이미지 등을 수집한 후 각 게시물의 텍스트, 해시태그, 업로드 날짜, '좋아요' 수, 댓글 등을 분석하였다. 연구 결과, 도서관 인스타그램의 활성화를 위해서는 팔로워 증가, 이용자 맞춤 게시물 업로드, 계정 프로필의 공식화, 도서관만의 해시태그 활용, 이용자와의 소통이 필요한 것으로 나타났다.

• 천문학회지
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• 제52권1호
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• pp.11-21
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• 2019

Intensive Monitoring Survey of Nearby Galaxies (IMSNG) is a high cadence observation program monitoring nearby galaxies with high probabilities of hosting supernovae (SNe). IMSNG aims to constrain the SN explosion mechanism by inferring sizes of SN progenitor systems through the detection of the shock-heated emission that lasts less than a few days after the SN explosion. To catch the signal, IMSNG utilizes a network of 0.5-m to 1-m class telescopes around the world and monitors the images of 60 nearby galaxies at distances D < 50 Mpc to a cadence as short as a few hours. The target galaxies are bright in near-ultraviolet (NUV) with $M_{NUV}$ < -18.4 AB mag and have high probabilities of hosting SNe ($0.06SN\;yr^{-1}$ per galaxy). With this strategy, we expect to detect the early light curves of 3.4 SNe per year to a depth of R ~ 19.5 mag, enabling us to detect the shock-heated emission from a progenitor star with a radius as small as $0.1R_{\odot}$. The accumulated data will be also useful for studying faint features around the target galaxies and other science projects. So far, 18 SNe have occurred in our target fields (16 in IMSNG galaxies) over 5 years, confirming our SN rate estimate of $0.06SN\;yr^{-1}$ per galaxy.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.335-335
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• 2014

Over the past several years, transparent conducting oxides have been extensively studied in order to replace indium tin oxide (ITO). Here we report on fluorine doped zinc tin oxide (FZTO) films deposited on glass substrates by radio-frequency (RF) magnetron sputtering using a 30 wt% ZnO with 70 wt% SnO2 ceramic targets. The F-doping was carried out by introducing a mixed gas of pure Ar, CF4, and O2 forming gas into the sputtering chamber while sputtering ZTO target. Annealing temperature affects the structural, electrical and optical properties of FZTO thin films. All the as-deposited FZTO films grown at room temperature are found to be amorphous because of the immiscibility of SnO2 and ZnO. Even after the as-deposited FZTO films were annealed from $300{\sim}500^{\circ}C$, there were no significant changes. However, when the sample is annealed temperature up to $600^{\circ}C$, two distinct diffraction peaks appear in XRD spectra at $2{\Theta}=34.0^{\circ}$ and $52.02^{\circ}$, respectively, which correspond to the (101) and (211) planes of rutile phase SnO2. FZTO thin film annealed at $600^{\circ}C$ resulted in decrease of resistivity $5.47{\times}10^{-3}{\Omega}cm$, carrier concentration ~1019 cm-3, mobility~20 cm2 V-1s-1 and increase of optical band gap from 3.41 to 3.60 eV with increasing the annealing temperatures and well explained by Burstein-Moss effect. Change of work function with the annealing temperature was obtained by ultraviolet photoemission spectroscopy. The increase of annealing temperature leads to increase of work function from ${\phi}=3.80eV$ (as-deposited FZTO) to ${\phi}=4.10eV$ ($600^{\circ}C$ annealed FZTO) which are quite smaller than 4.62 eV for Al-ZnO and 4.74 eV for SnO2. Through X-ray photoelectron spectroscopy, incorporation of F atoms was found at around the binding energy of 684.28 eV in the as-deposited and annealed FZTO up to 400oC, but can't be observed in the annealed FZTO at 500oC. This result indicates that F atoms in FZTO films are loosely bound or probably located in the interstitial sites instead of substitutional sites and thus easily diffused into the vacuum from the films by thermal annealing. The optical transmittance of FZTO films was higher than 80% in all specimens and 2-3% higher than ZTO films. FZTO is a possible potential transparent conducting oxide (TCO) alternative for application in optoelectronics.

• 한국표면공학회지
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• 제52권6호
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• pp.334-341
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• 2019

Organometal halide perovskite materials have attracted much attention in the photovoltaic and light emitting devices due to the compositional flexibility with AMX₃ formula (A is an organic amine cation; M is a metal ion; X is a halogen atom). The addition of homovalent or heterovalent metal cations to the bulk organohalide perovskites has been performed to modify their energy band structure and the relevant optoelectronic properties by ligand-assisted ball milling. Here, we report CH₃NH₃Pb_1-xM_xBr₃ nanocrystals substituted by metallic cations (M is Sn²⁺, In³⁺, Bi³⁺; x = 0, 0.01, 0.02, 0.05, 0.1, 0.2). Photoluminescence and quantum yield was significantly reduced with increasing metallic cations content. These quenching effect could be resulted from the metal cations that behave as a non-radiative recombination center.

• 한국식품영양과학회지
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• 제40권9호
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• pp.1256-1264
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• 2011

시중에 유통되고 있는 조제분유의 지방산 및 TAG 조성을 알아보기 위하여 국내외 조제분유 총 11 품목을 선정하였고, Folch법을 이용하여 지방을 추출한 다음 총 지방산과 sn-2 위치의 지방산 및 silver ion HPLC를 이용한 단일불포화-포화-단일불포화 glycerol(MSM)의 조성을 분석하였다. 조제분유의 조지방의 함량은 17.21~23.51%이었고, 특히 K5의 조지방 함량이 23.51%로써 분석된 조제분유들 중에서 가장 높게 나왔으나, K1은 17.21%의 함량을 보이면서 가장 낮게 나타났다. 분석된 조제분유들의 주요 포화지방산은 lauric acid(C12:0), myristic acid(C14:0), palmitic acid(C16:0), stearic acid(C18:0)이었다. Lauric acid의 함량은 K5와 K6에서 19.49%와 23.34%로 분석되어 15%보다 높은 함량을 나타냈다. 한편, 분석된 조제분유의 palmitic acid의 함량은 7.59~21.65%의 범위로써 K2, K3, K6, F1에서 각각 14.64%, 8.29%, 13.47% 및 7.59%로써 낮은 함량을 나타냈다. 불포화 지방산들 중에서 단일불포화지방산(C14:1, myristoleic acid; C16:1, palmitoleic acid; C17:1, heptadecenoic acid; C18:1, oleic acid; C18:1t, elaidic acid)의 함량은 20.23~45.07%로 나타났고, 단일불포화지방산들 중에서 대부분을 구성하고 있는 지방산은 oleic acid(C18:1)이었다. 분석된 조제분유에서 oleic acid의 함량은 19.64~44.64%의 범위였고 총 다가불포화지방산은 19.08~29.67%의 범위였다. Omega-6 다가불포화지방산과 omega-3 다가불포화지방산의 주요한 지방산은 필수지방산인 linoleic acid(C18:2)와 linolenic acid(C18:3, n-3)로 분석된 조제분유의 비율은 10:1~13:1로, 조제분유의 지방산 조성에 대한 지표인 linoleic acid/linolenic acid의 비율인 5:1~15:1 범위 내였다. 분석한 조제분유들 중에서 sn-2 위치에서의 lauric acid 함량은 7.70~52.09%로 나타났고, myristic acid의 함량은 3.15~20.89%로써 분석된 조제분유들은 전반적으로 sn-2 위치에서의 lauric acid 함량이 20% 이상으로 높게 나타났다. 특히, 분석된 조제분유들의 sn-2 위치에 존재하는 palmitic acid의 함량은 1.84~38.74%의 범위로써 K8과 F3이 각각 38.55%와 38.90%의 높은 함량을 나타냈다. 따라서 대부분의 국내외 조제분유들을 구성하는 triacylglycerol(TAG)의 sn-2 위치에서의 palmitic acid 함량이 모유와 비교하였을 때 낮은 경향을 보임을 알 수 있었다. 이러한 조제분유보다 더 나아가 HPLC 분석을 통해서 모유의 주요 TAG 형태라고 할 수 있는 단일불포화-포화-단일불포화 glycerol(MSM)의 함량이 외국의 조제분유인 F3이 가장 높게 나타났다. 따라서 조제분유에 이러한 MSM 형태의 지방 함량을 높여야하며, MSM 형태의 모유대체지 연구를 산업화하려는 노력이 필요하다.

• Journal of Electrochemical Science and Technology
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• 제7권1호
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• pp.52-57
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• 2016

Nanoporous-layer-covered TiO₂ nanotube arrays (Type II TNTs) were fabricated by two-step electrochemical anodization. For comparison, conventional TiO₂ nanotube arrays (Type I TNTs) were also prepared by one-step electrochemical anodization. Types I and II TNTs were detached by selective etching and then transferred successfully to a transparent F-doped SnO₂ (FTO) substrate by a sol-gel process. Both FTO/Types I and II TNTs allowed front side illumination to exhibit incident photon-to-current efficiencies (IPCEs) in the long wavelength region of 300 to 750 nm without the absorption of light by the iodine-containing electrolyte. The Type II TNT exhibited longer electron lifetime and faster charge transfer than the Type I TNT because of its relatively fewer defect states. These beneficial effects lead to a high overall energy conversion efficiency (5.32 %) of the resulting dye-sensitized solar cell.

• 복식
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• 제52권3호
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• pp.19-27
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• 2002

This paper surveys the mordanting and dyeing properties of Sophora japonica L. Appropriate extraction, dyeing and mordanting condition of Sophora japonica L. were determined, and the effect of mordanting method on dye uptake and color fastness of dyed fabric was investigated. The maximum absorbance of Sophora japonica L. solution was 367.6mn, rutin solution was 365.6mn. The color of Sophora japonica L. solution was affected at pH 2 and pH 8~9. The optimum temperature to extract Sophora japonica L. was during 1 hour in 8$0^{\circ}C$. The effective dyeing temperature and time of silk were 10$0^{\circ}C$, 60min. K/S value of dyeing fabrics was increased by pre-mordanting treatment, especially Fe, Sn, Cr. In the case of Sophora japonica L. light fastness was increased by Fe mordanting. Perspiration fastness was better in acidic solution than that in alkaline solution. Fastness to rubbing and dry-cleaning were good in general.

• 대한치과교정학회지
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• 제49권6호
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• pp.360-371
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• 2019

Objective: We sought to determine the predictors of midpalatal suture expansion by miniscrew-assisted rapid palatal expansion (MARPE) in young adults. Methods: The following variables were selected as possible predictors: chronological age, palate length and depth, midpalatal suture maturation (MPSM) stage, midpalatal suture density (MPSD) ratio, the sella-nasion (SN)-mandibular plane (MP) angle as an indicator of the vertical skeletal pattern, and the point A-nasion-point B (ANB) angle for anteroposterior skeletal classification. For 31 patients (mean age, 22.52 years) who underwent MARPE treatment, palate length and depth, MPSM stage and MPSD ratio from the initial cone-beam computed tomography images, and the SN-MP angle and ANB angle from lateral cephalograms were assessed. The midpalatal suture opening ratio was calculated from the midpalatal suture opening width measured in periapical radiographs and the MARPE screw expansion. Statistical analyses of correlations were performed for the entire patient group of 31 subjects and subgroups categorized by sex, vertical skeletal pattern, and anteroposterior skeletal classification. Results: In the entire patient group, the midpalatal suture opening ratio showed statistically significant negative correlations with age, palate length, and MPSM stage (r = -0.506, -0.494, and -0.746, respectively, all p < 0.01). In subgroup analyses, a strong negative correlation was observed with the palate depth in the skeletal Class II subgroup (r = -0.900, p < 0.05). Conclusions: The findings of this study indicated that age, palate length, and MPSM stage can be predictors of midpalatal suture expansion by MARPE in young adults.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.28-31
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• 2001

Recently, in order to satisfy the consumer's demand the life cycle and the lead-time of a product is to be shortened. It is thus important to reduce the time and cost in manufacturing trial products. Several techniques have been developed and successfully commercialized in the market RPM(Rapid Prototyping and Manufacturing). However, most commercial systems currently use resins or waxes as the raw materials. So, the limited mechanical strength for functional testing is regarded as an obstacle towards broader application of rapid prototyping techniques. To overcome this problems, high-speed machining technology is being investigated worldwide for rapid manufacturing and even for direct rapid tooling application. In this paper, some fundamental experiments and analyses are carried out to obtain the filling time, materials, method, and process parameters for HisRP process. HisRP is a combination process using high-speed machining technology with automatic filling. In filling process, Bi58-Sn alloy is chosen because of the properties of los-melting point, low coefficient of thermal expansion and enviromental friendship. Also the use of filling wire is of advantage in term of simple and flexible mechanism. Then the rapid manufacturing product, for example a skull, is machined for aluminum material by HisRP process with an automatic set-up device of 4-faces machining.