• Wind and Structures
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• 제36권3호
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• pp.201-213
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• 2023

In this study, the effect of sea surface temperature (SST) on the distribution of vertical wind speed in the atmospheric boundary layer of coastal areas was analyzed. In general, coastal areas are known to be more susceptible to various meteorological factors than inland areas due to interannual changes in sea surface temperature. Therefore, the purpose of this study is to analyze the relationship between sea surface temperature (ERA5) and wind resource data based on the meteorological mast of Høvsøre, the test bed area of the onshore wind farm in the coastal area of Denmark. In addition, the possibility of coastal disasters caused by abnormal vertical wind shear due to changes in sea surface temperature was also analyzed. According to the analysis of the correlation between the wind resource data at met mast and the sea surface temperature by ERA5, the wind speed from the sea and the vertical wind shear are stronger than from the inland, and are vulnerable to seasonal sea surface temperature fluctuations. In particular, the abnormal vertical wind shear, in which only the lower wind speed was strengthened and appeared in the form of a nose, mainly appeared in winter when the atmosphere was near-neutral or stable, and all occurred when the wind blows from the sea. This phenomenon usually occurred when there was a sudden change in sea surface temperature within a short period of time.

• Transactions on Electrical and Electronic Materials
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• 제2권3호
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• pp.18-23
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• 2001

For the piezoelectric transformer application, Pb(Sb$\_$1/2/ Nb$\_$1/2/)O$_3$-Pb(Zr,Ti)O$_3$ ceramics were produced by attrition milling. Microstructural, dielectric and piezoelectric characteristics of the ceramics were investigated as a function of milling time. The particle size and grain size decreased while dielectric constant, density and mechanical quality factor (Q$\_$m/) increased with milling time. Temperature coefficient of resonant frequency (TCf$\_$r/) was shifted to positive side with increasing milling time. The attrition milling process proved to be one of the effective routes to produce transformers for high power application.

• 전기전자학회논문지
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• 제19권4호
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• pp.479-485
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• 2015

A resistance deviation-to-time interval converter based on dual-slope integration using second generation current conveyors (CCIIs) is designed for connecting resistive bridge sensors with a digital system. It consists of a differential integrator using CCIIs, a voltage comparator, and a digital control logic for controlling four analog switches. Experimental results exhibit that a conversion sensitivity amounts to $15.56{\mu}s/{\Omega}$ over the resistance deviation range of $0-200{\Omega}$ and its linearity error is less than ${\pm}0.02%$. Its temperature stability is less than $220ppm/^{\circ}C$ in the temperature range of $-25-85^{\circ}C$. Power dissipation of the converter is 60.2 mW.

• 한국재료학회지
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• 제30권11호
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• pp.615-620
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• 2020

Oxide semiconductor, represented by a-IGZO, has been commercialized in the market as active layer of TFTs of display backplanes due to its various advantages over a-Si. a-IGZO can be deposited at room temperature by RF magnetron sputtering process; however, additional thermal annealing above 300℃ is required to obtain good semiconducting properties and stability. These temperature are too high for common flexible substrates like PET, PEN, and PI. In this work, effects of microwave annealing time on IGZO thin film and associated thin-film transistors are demonstrated. As the microwave annealing time increases, the electrical properties of a-IGZO TFT improve to a degree similar to that during thermal annealing. Optimal microwave annealed IGZO TFT exhibits mobility, SS, V_th, and V_H of 6.45 ㎠/Vs, 0.17 V/dec, 1.53 V, and 0.47 V, respectively. PBS and NBS stability tests confirm that microwave annealing can effectively improve the interface between the dielectric and the active layer.

• 조명전기설비학회논문지
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• 제22권4호
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• pp.107-113
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• 2008

본 실험은 구동 온도와 방전관의 길이에 따라 변화하는 ICP 광원의 전기 광학적 특성에 대해서 알아보았다. 광원의 전기 광학적 특성이 정상상태에 놓이는 구동 조건을 확인하기 위하여 시간에 따른 전력 소모와 광속의 변화를 측정하였다. 전력소모와 광속의 시간에 따른 변화를 측정한 결과를 통해서 볼 때 최초구동에서 70분이 경과한 이후부터 전력소모는 초기값에 대해 1.45[%], 광속은 0.36[%]의 안정성을 나타냈다. 항온챔버 내에서 온도를 5구간으로 나뉘어 변화하면서 구동 온도에 따른 ICP 광원의 광학적 특성을 알아보았다. 휘도는 온도의 상승과 비례적으로 증가하였으나 $46.7[^{\circ}C]$ 이상에서는 오히려 감소하는 결과를 얻을 수 있었다. 파센법칙과 함께 보일-샤를의 법칙을 통해 0.02[Torr]의 압력이 변화함에 따라 더 높은 방전전압이 요구되지만 충분한 전압이 안정기에서 공급되지 못하기 때문이라 판단된다. 이와 더불어 방전관 길이에 따라 광원에 인가되는 전력과 전류을 측정하였다.

• 터널과지하공간
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• 제26권1호
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• pp.12-23
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• 2016

향후 국내에서 수행될 이산화탄소 지중저장 프로젝트의 성공적인 수행을 위해서는 현장 지질조건에 최적화된 주입 조건을 설계하는 것이 중요하다. 따라서 본 연구에서는 주입량 및 주입온도 등의 주입조건이 격리저장시스템의 역학적 안정성에 미치는 영향을 열-수리-역학 연계해석기법의 하나인 TOUGH-FLAC 해석기법을 이용하여 평가하였다. 저장시스템의 역학적 안정성은 기존 균열의 전단미끄러짐 발생가능성을 활동마찰각 및 응력원을 이용하여 분석하였다. 이산화탄소의 주입온도가 저류층의 초기온도보다 낮은 저온주입의 조건에도 열응력으로 인한 인장균열은 발생하지 않는 것으로 파악되었으나, 저류층에서 전단미끄러짐이 발생하는 결과를 보였다. 단위시간당 이산화탄소 주입량을 변화시킨 시나리오 해석에서는 단계별로 주입량을 감소시키는 주입시나리오에서 기존 균열들의 전단미끄러짐 발생 가능성이 가장 낮은 것으로 평가되었다.

• 한국임상약학회지
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• 제8권2호
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• pp.147-158
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• 1998

The purpose of this study was to test the stability of TPN basic solutions containing amino acids and dextrose. Test solutions containing $4.25\%$ amino acids in $25\%$ dextrose (central TPN basic solution) or $4.25\%$ amino acids in $10\%$ dextrose (peripheral TPN basic solution) were prepared. Two different amino acids solutions $(Fravasol^{(R)}\;vs\;Freamine^{(R)})$ were tested. The samples were taken from each admixture and stored in the evacuated, sterile containers at $2{\sim}8^{\circ}C$ and ambient room temperature. Each sample was analyzed at 0, 3, 7, 14 and 30 days of storage. Each amino acid was analyzed by amino acid analyzer. Dextrose content was measured by polarimeter. The pH and chromagen formation were also monitored. The decomposition was measured by the changes in concentration of amino acids and dextroser TPN basic $solution-Freamine^{(R)}$ admixture stored at $2\sim8^{\circ}C$ were stable for 30 days. Central and peripheral TPN basic solutions stored at room temperature were stable for 7 days and 14 days, respectively. There were no changes in color for 30 days by naked eye. Amino acid concentrations in TPN basic $solution-Fravasol^{(R)}$ admixture stored at $2\sim8^{\circ}C$ or room temperature were stable for 30 days. But, significant color change was detected according to passing time. In conclusion, Peripheral TPN basic $solution-Fravasol^{(R)}$ admixture stored at room temperature and in refrigerator were stable for 3 days and 7 days, respectively. However, central TPN basic solution-Fravasol admixtures were unstable. Therefore, it is recommended that it should be admixed right before use.

• JSTS:Journal of Semiconductor Technology and Science
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• 제14권1호
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• pp.53-60
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• 2014

Different kinds of post-deposition annealing (PDA) by a rapid thermal process (RTP) are used to enhance the field-effect passivation of $Al_2O_3$ film in crystal Si solar cells. To characterize the effects of PDA on $Al_2O_3$ and the interface, metal-insulator semiconductor (MIS) devices were fabricated. The effects of PDA were characterized as functions of RTP temperature from $400{\sim}700^{\circ}C$ and RTP time from 30~120 s. A high temperature PDA can retard the passivation of thin $Al_2O_3$ film in c-Si solar cells. PDA by RTP at $400^{\circ}C$ results in better passivation than a PDA at $400^{\circ}C$ in forming gas ($H_2$ 4% in $N_2$) for 30 minutes. A high thermal budget causes blistering on $Al_2O_3$ film, which degrades its thermal stability and effective lifetime. It is related to the film structure, deposition temperature, thickness of the film, and annealing temperature. RTP shows the possibility of being applied to the PDA of $Al_2O_3$ film. Optimal PDA conditions should be studied for specific $Al_2O_3$ films, considering blistering.

• Animal Bioscience
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• 제36권10호
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• pp.1596-1603
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• 2023

Objective: Sous-vide cooking offers several advantages for poultry meat, including enhanced tenderness, reduced cooking loss, and improved product yield. However, in duck meat, there are challenges associated with using the sous-vide method. The prolonged cooking time at low temperatures can lead to unstable microbial and oxidative stabilities. Thus, we aimed to assess how varying sous-vide cooking temperatures and durations affect the physicochemical and microbial characteristics of duck breast meat, with the goal of identifying an optimal cooking condition. Methods: Duck breast meat (Anas platyrhynchos) aged 42 days and with an average weight of 1,400±50 g, underwent cooking under various conditions (ranging from 50℃ to 80℃) for either 60 or 180 min. Then, physicochemical, microbial, and microstructural properties of the cooked duck breast meat were assessed. Results: Different cooking conditions affected the quality attributes of the meat. The cooking loss, lightness, yellowness, Hue angle, whiteness, and thiobarbituric acid reactive substance (TBARS) values of the duck breast meat increased with the increase in cooking temperature and time. In contrast, the redness and chroma values decreased with the increase in cooking temperature and time. Cooking of samples higher than 60℃ increased the volatile basic nitrogen contents and TBARS. Microbial analysis revealed the presence of Escherichia coli and Coliform only in the samples cooked at 50℃ and raw meat. Cooking at lower temperature and shorter time increased the tenderness of the meat. Microstructure analysis showed that the contraction of myofibrils and meat density increased upon increasing the cooking temperature and time. Conclusion: Our data indicate that the optimal sous-vide method for duck breast meat was cooking at 60℃ for 60 min. This temperature and time conditions showed good texture properties and microbial stability, and low level of TBARS of the duck breast meat.

• Macromolecular Research
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• 제12권6호
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• pp.545-552
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• 2004

The long-term stability of sulfonic acid-containing polyimides has been investigated. The hydrolytic degradation of homopolyimide and the block copolyimide comprising $27\;mol\%$ of 2,2'-bis(trifluoromethyl)benzidine and $9\;mol\%$ of m-phenylenediamine (BTFMB27mPl0[7/(3+1)]), was quantified through viscosity measurements and FT-IR spectroscopic analyses. The viscosity decrease with respect to time and the degradation rate were similar. The degrees of degradation with respect to time under ambient conditions and at elevated temperature in water were monitored by FT-IR spectroscopy. A new absorption peak was observed at $1786\;cm^{-1},$ which we corresponds to the presence of anhydride end groups formed by hydrolytic scission of the imide rings.