• Journal of the Microelectronics and Packaging Society
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• v.24 no.2
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• pp.69-74
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• 2017

Effect of post-annealing treatment times at $200^{\circ}C$ on the peel strength of screen-printed Ag film/polyimide substrate were systematically investigated by $180^{\circ}$ peel test for thermal reliability assessment of printed interconnect. Initial peel strength around 16.7 gf/mm increased up to 29.4 gf/mm after annealing for 24hours, and then sharply decreased to 22.3, 3.6, 0.6, and 0.1 gf/mm after 48, 100, 250, and 500 hours, respectively. Ag-O-C chemical bonding as well as binder organic bridges formations seemed to be responsible for interfacial adhesion improvement after the initial annealing treatment, while excessive Cu oxide formation at Cu/Ag interface seems to be closely related to sharp decrease in peel strength for longer annealing times.

• Korean Journal of Agricultural Science
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• v.2 no.1
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• pp.101-110
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• 1975

This study was carried out to determine the effect of water control on Rice plan in warmer season(July~August). The results are summarized as follows; 1. Compared to ordinary watering methods, a constant irrigation method indicated a decrease in water temperature of $1.5^{\circ}C$. 2. In the plot of constant irrigation, there was an increase in the root system in general and an increase of root distribution near the surface in particular. The near surface root distribution under ordinary watering method shows about forty percent distribution. The constant irrigation method shows a near-surface root distribution of sixty-percent within a perimeter of five centimeters. 3. Under the contants irrigation method, there was an increase in length and area of the flag leaf. 4. The total nitrogen and silica content of leaf-bodies at maturing stage was greater when using the constant irrigation method. 5. There was an increase in the number of panicles and the number of spikelets when using the constant irrigation method. 6. The yield was remarkably increased with constant irrigation.

• Polymer(Korea)
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• v.33 no.1
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• pp.19-25
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• 2009

New polyelectrolytes derived from ionene-containing photocurable reactive oligomer (PIDM) were prepared for water-resistant humidity-sensitive membranes. The mixture of PIDM, hexamethylene dimethacrylate (HDM), pentaerythritol triacrylate dimer (SP1013), and photoinitiator was simultaneously coated on the sensor electrode with photoinitiated radical polymerization. The pretreatment of the substrates with vinyl-type silane-coupling reagent was performed for improving the water durability and stability of the sensors at high temperature and humidity. When the resistance dependences on the relative humidity of the crosslinked PIDMs were measured, it was found that the resistance varied three orders of magnitude between 20 and 90%RH, which was required for the humidity sensor operating at ambient humidity. Their hysteresis, temperature dependence, response time, water durability, and high temperature/humidity stabilities were measured and evaluated as a humidity-sensing membrane.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.416-416
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• 2010

본 연구에서는 저가격, 대면적화를 위한 롤투롤 스퍼터를 설계&개발하고, 성막직전 PET 기판의 열처리 유무를 통한 ITO 박막을 성막 시킨 저항막 방식의 터치 패널용 투명 전극에 대하여 전기적, 광학적, 구조적, 표면적 특성을 분석하였다. 롤투롤 스퍼터는 degassing챔버와 스퍼터 챔버가 한 시스템에 구성되었고, Degassing 챔버는 좌우측의 Rewinder/Unwinder 롤러에 의해 감고 풀어지는 PET기판의 수분 및 가스를 중앙부에 위치한 히터를 통해 제거하며, 수분 제거 후 스퍼터 챔버로 옮겨진 1250 mm폭의 PET기판을 Unwinder/Rewinder 롤러에 장착하며, Unwinder 롤러로부터 풀려진 PET 기판은 guide 롤러를 거쳐 cooling drum과의 물리적 접촉에 의해 PET 기판의 냉각이 일어나게 된다. ITO 캐소드 전에 장착된 할로겐 히터 상부로 기판이 지나가면서 열처리가 진행되고 열처리 후 두 개의 ITO 캐소드 상부를 지나면서 연속적으로 ITO 박막이 PET 기판에 성막 되게 된다. ITO 박막의 주요 성막 변수인 DC Power, Ar/$O_2$ 가스 유량비, 기판의 속도는 최적으로 고정하고, 성막 직전 기판의 열처리에 유무에 따른 ITO박막의 필름을 각각 고온 챔버에서 $140^{\circ}C{\times}90min$ 동안 열처리를 통한 내열성 테스트를 진행하여 ITO 필름의 특성 향상을 비교 분석하였다. 분석을 위해 전기적 특성은 four-point probe로 측정했고, 투과도는 Nippon Denshoku사(社)의 COH-300A를 이용해 가시광(550nm)에서 분석했고, FE-SEM으로 ITO박막 의 표면 상태를 분석하였다. 또한 Bending Tester(Z-100)를 이용하여 기계적 안정성을 분석하였다. 성막직전 PET 기판의 열처리를 하지 않은 ITO박막은 고온의 챔버 에서 $140^{\circ}C{\times}90min$ 동안 내열성 테스트 후 면저항이 511($\omega/\Box$)에서 630($\omega/\Box$)으로 높아졌으나, 성막직전 열처리를 통한 ITO 박막인 경우에는 465($\omega/\Box$)에서 448($\omega/\Box$)로 안정화 되었고, 투과율은 성막직전 열처리를 통해 1%향상되어 89%를 보였고, 유연성 또한 보다 우수한 특성을 보였다. 표면 조도는 평균 0.416 nm의 낮은 값을 보였다. 이는 PET 기판의 degassing 공정 중 충분히 제거되지 않은 가스나 불순물을 성막직전 열처리 공정으로 충분히 제거하여 깨끗한 PET 기판 상에 ITO 박막을 성막시키고, 열처리시 기판에 주어진 열에너지에 의해 보다 밀도가 높은 ITO 박막이 성장했기 때문으로 사료 된다.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.290.2-290.2
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• 2013

X-선 튜브는 의료 영상 및 치료, 산업용 제전 장치, 비파괴 X-선 영상 장치 등에서 사용되는데 기존의 열전자원을 이용한 X-선 튜브와는 달리, 냉음극형 X-선 튜브는 빠른 속도의 디지털 구동이 가능하며 전력 소비가 낮은 장점이 있다. 따라서, 최근 많은 연구자들에 의해서 냉음극형 X-선 튜브에 관한 연구가 활발하게 진행되고 있다. 냉음극형 X-선 튜브는 전계 방출을 이용한 전자원을 사용하며, 탄소나노튜브 (CNT), Si, 다양한 종류의 나노선 등이 대표적이다. 그 중에서 CNT는 높은 종횡비로 인해 전계 방출 특성이 우수하여 가장 대표적인 물질이다. CNT를 이용한 전자원을 제작하기 위해서는 직접 성장법, 전기영동법, 스크린 프린팅법, 디핑법 등 다양한 방법이 존재한다. 직접 성장법을 제외한 방법들은 모재료인 CNT와 용매, 금속재료들을 섞어 페이스트나 수용액의 상태를 제작하여야 한다. 이 때, 금속 재료는 기판과 CNT간의 접착 및 전자 전도 통로의 역할을 하는 무기 충전제이며 일반적으로 나노 혹은 수 마이크로미터 크기의 상태로 존재하는 것을 주로 사용한다. X-선 튜브 제작은 일반적으로 외벽을 유리 혹은 세라믹을 주로 사용하는데 아노드 전극 및 캐소드 전극 등과 결합하여 진공 밀봉된 형태가 되어야 한다. 브레이징 방법은 금속과 세라믹을 결합하는데 매우 유용한 방법이며, 그 중에서도 진공 브레이징 방법은 다량의 부품을 한 번에 결합시킬 수 있다. 하지만 진공 브레이징 공정의 온도는 약 $700{\sim}1,000^{\circ}C$이며 이는 금속 재료가 충분히 증발할 수 있는 온도가 된다. 본 발표에서는 고온 진공 상태에서의 무기 충전제의 증발에 대한 현상을 관찰하고 고온진공 상태에서 증발없이 무기 충전제로의 역할을 할 수 있도록 다양한 금속 및 합금에 대한 연구를 수행하였다. 또한, 이 연구를 통해 선택된 무기 충전제를 포함하여 CNT 페이스트를 볼밀링 방법을 이용하여 제작하였으며, 이를 이용한 CNT 에미터가 X-선 튜브의 전자원으로 사용될 수 있는지 확인하기 위해 전계 방출 실험을 함께 실시하였다. 제작된 CNT 에미터가 우수한 전계 방출 특성을 가지고 있음을 확인하였으며, 이는 본 연구를 통해 선택된 금속 및 합금 재료가 무기 충전제로의 역할을 잘 수행하고 있음을 보여준다.

• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.286-291
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• 2022

The effect of root-zone local cooling on seedling growth of tomato was investigated. Lower pipe cooling was used for local cooling of the root zone, and the root zone temperature was set at 20 and 25℃. There was no difference in plant height, root length, and leaf number according to local cooling temperature. Leaf area, fresh weight, dry weight, and chlorophyll content of the shoot and root was higher in the 25℃ than those of 20℃ at 28 DAS. These results showed that cooling for seedling growth of tomato 25℃ is sufficient considering energy efficiency. This study will be helpful in the development of local cooling technology that can reduce the energy required for cooling during the production of tomato seedlings in the high temperature season.

• Nuclear Engineering and Technology
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• v.27 no.4
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• pp.518-531
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• 1995

A study has been Peformed to investigate the thermal margin increase by replacing the single-channel analysis model with a multichannel analysis model. h new critical heat flux(CHF) correlation, which is applicable to a 17$\times$17 Korean Fuel Assembly(KOFA)-loaded core, was developed on the basis of the local conditions predicted by the subchannel analysis code, TORC. The hot sub-channel analysis was carried out by using one-stage analysis methodology with a prescribed nodal layout of the core. The result of the analysis shooed that more than 5％ of the thermal margin can be recovered by introducing the TORC/KRB-1 system(multichannel analysis model) instead of the PUMA/ERB-2 system(single-channel anal)sis model). The thermal margin increase was attributed not only to the effect of the local thermal hydraulic conditions in the hot subchannel predicted by the code, but also to the effect of the characteristics of the CHF correlation.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.1
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• pp.38-46
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• 2022

Two different gas diffusion layers having noticeable differences in micro-porous layer's (MPL's) crack were studied as a substrate for the gas diffusion electrode (GDE) with different binder/carbon (B/C) ratios in high-temperature polymer electrolyte fuel cell (Ht-PEMFC). As a result, the performance defined as the voltage at 0.2 A/cm² and maximum power density from the single cells using GDEs from H23 C2 and SGL38 BC with different B/C ratios were compared. GDEs from H23 C2 showed a proportional increase of the voltage with the binder content on the other hand GDEs from SGL38 BC displayed a proportional decline of the voltage to the binder content. It was revealed that MPL crack influences the structure of catalyst layer in GDEs as well as affects the RC_athode which is in close connection with the Ht-PEMFC performance.

• Journal of Bio-Environment Control
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• v.18 no.2
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• pp.160-165
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• 2009

This study was undertaken the effect of high temperature and high humidity on protein expression and especially plasma membrane (PM) $H^{+}ATPase$ of umbel with flowers of early cultivar 'Shinsunhwang' and intermediate cultivar 'Maebsihwang' of onion (Allium cepa L.). There were no visible any difference on the protein pattern from before flowering stage to full flowering stage of two onion cultivars, however, seed set stages were revealed induced/deduced protein patterns. At day 18, protein expression pattern of the high temperature and high humidity treatments of two cultivars was significantly reduced compared to controls. Furthermore, various protein expression of the high temperature treatment was more reduced compared to high humidity treatment. PM $H^{+}ATPase$ expression of the control plants of two onion cultivars was clearly shown, but was not detectable under high temperature treatment of the two onion cultivars using western blot analysis. PM $H^{+}ATPase$ expression of the high humidity treatment was faintly detected intermediate cultivar 'Maebsihwang', not early cultivar 'Shinsunhwang'. These results indicate that protein expression pattern and PM $H^{+}ATPase$ under high temperature treatment was considered to be more damaged compared to high humidity.

• Korean Journal of Agricultural and Forest Meteorology
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• v.24 no.4
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• pp.218-233
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• 2022

The long-term (1986~2020) predictability of the number of days of heat and cold damages for each growth stage of soybean is evaluated using the daily maximum and minimum temperature (Tmax and Tmin) data produced by Pusan National University Coupled General Circulation Model (PNU CGCM)-Weather Research and Forecasting (WRF). The Predictability evaluation methods for the number of days of damages are Normalized Standard Deviations (NSD), Root Mean Square Error (RMSE), Hit Rate (HR), and Heidke Skill Score (HSS). First, we verified the simulation performance of the Tmax and Tmin, which are the variables that define the heat and cold damages of soybean. As a result, although there are some differences depending on the month starting with initial conditions from January (01RUN) to May (05RUN), the result after a systematic bias correction by the Variance Scaling method is similar to the observation compared to the bias-uncorrected one. The simulation performance for correction Tmax and Tmin from March to October is overall high in the results (ENS) averaged by applying the Simple Composite Method (SCM) from 01RUN to 05RUN. In addition, the model well simulates the regional patterns and characteristics of the number of days of heat and cold damages by according to the growth stages of soybean, compared with observations. In ENS, HR and HSS for heat damage (cold damage) of soybean have ranged from 0.45~0.75, 0.02~0.10 (0.49~0.76, -0.04~0.11) during each growth stage. In conclusion, 01RUN~05RUN and ENS of PNU CGCM-WRF Chain have the reasonable performance to predict heat and cold damages for each growth stage of soybean in South Korea.