• 설비공학논문집
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• 제13권11호
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• pp.1165-1173
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• 2001

The objectives of this study are to analyze the application of radiant floor cooling and to evaluate the control methods through experiments when the radiant heating system is used for cooling. Through the experiment analysis the control methods such as on/off control, variable flow control and outdoor reset with indoor temperature feedback control are evaluated and compared. The cooling curve (reset ratio) is found for radiant cooling, which shows tole relation between outside air temperature and supply water temperature. Comparison of cooling methods shows that outdoor reset with indoor temperature feedback control is more appropriate than on/off control and variable flow control with regard to prevention of the condensation and thermal comfort.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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• pp.141-144
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• 2005

Rip-off failure and Debonding failure were commonly reported premature failure modes. The main reasons of premature failure in RC beams bonded with FRP were strengthening length and the reinforcement ratio. in this study, On the basis of premature failure mechanism in RC beams bonded with FRP, premature failure criteria were proposed. Also It was verified that Rip-off failure and Debonding failure occured according to premature failure criteria

• 한국잠사곤충학회지
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• 제13권1호
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• pp.73-78
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• 1971

본시험은 공정거래를 기할 수 있도록 진섬유량으로부터 생사의 거래중량을 산정할 수 있는 정량거래방법 을 구명하기 위한한 연구로서 다음과 같은 결과를 얻었다. 1. 거래중량인 정량은 원량에서 연감후무수량을 감한 연감수분량의 원량에 대한 백분률인 연감수분률로 부터 산정하면 생사의 진섬유량을 잘 나타낼 수 있고 재현성이 있어 현행검사보다 합리적이다. 2. 연감수분률로부터 정량을 산정함에 있어서 연감후무수량에 대한 공정가산률은 44%로 함이 적당하다고 판단된다. 3. 섬도검사 잔사인 섬도사의 연감률과 하구의 연감률을 대표할 수 있을 것으로 생각되는 시료사(24타래) 의 연감률 사이에 통계적인 유의차가 없었으므로 섬도사의 연감률은 하구의 연감률을 대표할 수 있다. 4. 우리나라는 연감수분율검사에 의한 정량검사를 실시하면 약 2억원의 이득을 얻을 수 있다.

• 천문학회보
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• 제41권1호
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• pp.81.3-81.3
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• 2016

We examine whether the observational stand-off distance ratios of CMEs and their associated ICMEs could be explained by theoretical model or not. For this, we select 16 CME-ICME pairs from September 2009 to October 2012 with the following conditions: (1) limb CMEs by SOHO and their associated ICMEs by twin STEREO spacecraft and vice versa when both spacecraft were roughly in quadrature; (2) the faint structure ahead of a limb CME is well identified; and (3) its associated ICME clearly has a sheath structure. We determine the observational stand-off distance ratios of the CMEs by using brightness profiles from LASCO-C2 (or SECCHI-COR2) observations and those of the ICMEs by solar wind data from STEREO-IMPACT/PLASTIC (or OMNI database) observations. We also determine the theoretical stand-off distance ratios of the CME-ICME pairs using semi-empirical relationship based on the bow shock theory. We find the following results. (1) Observational CME stand-off distance ratio decreases with increasing Mach number at the Mach numbers between 2 and 6. This tendency is consistent with the results from the semi-empirical relationship. (2) The observational stand-off distance ratios of several ICMEs can be explained by the relationship.

• 한국정보시스템학회지:정보시스템연구
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• 제14권2호
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• pp.277-292
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• 2005

This paper uses a data mining approach to develop bankruptcy prediction models suitable for traditional (off-line) companies and electronic (on-line) companies. It observes the differences in the composition prediction models between these two types of companies and provides interpretation of bankruptcy classifications. The bankruptcy prediction models revealed the major variables in predicting bankruptcy to be 'cash flow to total assets' and 'gross value-added to net sales' for traditional off-line companies while 'cash flow to liabilities','gross value-added to net sales', and 'current ratio' for electronic companies. The accuracy rates of final prediction models for traditional off-line and electronic companies were found to be $84.7\%\;and\;82.4\%$, respectively. When the model for traditional off-line companies was applied for electronic companies, prediction accuracy dropped significantly in the case of bankruptcy classification (from $70.4\%\;to\;45.2\%$) at the level of a blind guess ($41.30\%$). Therefore, the need for different models for traditional off-line and electronic companies is justified.

• 한국세라믹학회지
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• 제28권3호
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• pp.243-251
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• 1991

High-Tc YBa2Cu3O7-x superconducting thin films have been prepared by single-target off-axis RF magnetron sputtering. Optimal ratio of Y : Ba : Cu of the single-target was determined as 1 : 1.65 : 3.35 in order to obtain the stoichiometric films. Tc, crystalline phase, and microstructures of the surface and cross-section of the ex-situ YBa2Cu3O7-x thin films on MgO(100) had a Tc, zero of 80K, and the films on LaAlO3/Si had a Tc, on-set of 90 K and a Tc, zero of 70 K.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 춘계학술대회 논문집
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• pp.17-17
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• 2009

We report the invention of a direct growth method termed On-Film Formation of Nanowire (OFF-ON) for making high-quality single-crystal nanowires, i.e. Bi and $Bi_2Te_3$, without the use of conventional templates, catalysts, or starting materials. We have used the OFF-ON technique to grow single crystal semi-metallic Bi and compound semiconductor $Bi_2Te_3$ nanowires from sputtered Bi and BiTe films after thermal annealing, respectively. The mechanism for nanowire growth is stress-induced mass flow along grain boundaries in the polycrystalline films. OFF-ON is a simple but powerful method for growing perfect single-crystal semi-metallic and compound semiconductor nanowires of high aspect ratio with high crystallinity that distinguishes it from other competitive growth approaches that have been developed to date. Our results suggest that Bi and $Bi_2Te_3$ nanowires grown by OFF-ON can be an ideal material system for exploring their unique thermoelectric properties due to their high-quality single crystalline and high conductivity, which have consequence and relevance for high-efficiency thermoelectric devices.

• Transactions on Electrical and Electronic Materials
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• 제8권4호
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• pp.166-169
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• 2007

In applying LCD to TV application, one of the most significant factors to be improved is image sticking on the moving picture. LCD is different from CRT in the sense that it's continuous passive device, which holds images in entire frame period, while impulse type device generate image in very short time. To reduce image sticking problem related to hold type display mode, we made an experiment to drive TN-LCD like CRT. We made articulate images by turn on-off backlight, and we realized the ratio of Back Light on-off time by counting between on time and off time for video signal input during 1 frame (16.7 ms). Conventional CCFL (cold cathode fluorescent lamp) cannot follow fast on-off speed, so we evaluated new fluorescent substances of light source to improve residual light characteristic of CCFL. We realized articulate image generation similar to CRT by CCFL blinking drive and TN-LCD overdriving. As a result, reduced image sticking phenomenon was validated by naked eye and response time measurement.

• Ocean and Polar Research
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• 제39권1호
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• pp.35-43
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• 2017

Concentrations of dissolved organic carbon (DOC), dissolved organic nitrogen (DON), dissolved organic phosphate (DOP), and colored dissolved organic matter (CDOM) were measured in the coastal sea off inland aqua farms in northeastern Jeju Island in summer 2015. The highest concentrations of DOC, DON, and DOP were revealed in the surface water off Hado-ri where the lowest salinity conditions prevailed (31.6). The concentrations of DOC, DON, and DOP in the surface water were lower in the inner stations (SH1-1, 1-2, and 1-3) near the aqua farms of the Haengwon-ri than in the outer stations. The concentrations of DOC, DON, and DOP negatively correlated with salinity. These results indicate that the contribution of dissolved organic matter (DOM) from the aqua farms seems to be not significant. On the other hand, the higher concentrations of DON and DOP in the inner stations of Hado-ri (HD 1-1) seem to be attributed to excrement of migrating birds. The three components of CDOM (T, M, and C peaks) showed no relationship with salinity, perhaps due to various in situ productions by marine organisms and decomposition by ultraviolet radiation. The observed lower C:M ratio, an indicator of terrestrial source, and the higher biological index (BIX) of CDOM in the station off Hado-ri indicate that DOM is produced mainly by biological activity. Based on the higher humification index (HIX) of CDOM and the higher DOC:DON ratio off Haengwon-ri, refractory DOM in the inland aqua farms is likely transported to the coastal sea.

• 청정기술
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• 제30권1호
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• pp.13-22
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• 2024

본 연구에서는 6,13-Bis(triisopropylsilylethynyl)pentacene(TP):2-Decyl-7-phenyl[1]benzothieno[3,2-b][1]benzothiophene(BT):Poly styrene (PS) 블랜딩 thin film transistor (TFT)를 제작 광 흡수 센서로의 활용에 대해 탐구한다. BT의 혼합으로 인해 off current 감소와 on/off ratio 향상을 동시에 달성하였다. 특히, TP:BT:PS (1:0.25:1 w/w) 샘플은 우수한 광 흡수 특성을 보여주었고, 이를 통해 높은 성능의 광 흡수 장치 제작이 가능함을 입증했다. 다양한 혼합 비율의 결정 구조와 전기적 특성에 대한 분석을 통해 TP:BT:PS (1:0.25:1 w/w) 샘플이 최적임을 확인하였다. 이 결과는 광 흡수 장치의 발전 뿐만 아니라 혼합 organic semiconductor (OSC)의 광전자 시스템 개발에 긍정적인 기대효과를 미칠 수 있을 것이며, 이를 통해 단일 OSC 사용의 제약을 극복하고, 미세 조정된 광학 응답을 갖춘 고성능 OSC TFT를 제작하여 의료 전자소자, 산업용 전자소자 등에 응용할 수 있을 것으로 기대된다.