• Korean Journal of Food Science and Technology
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• v.39 no.6
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• pp.644-651
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• 2007

To establish the optimum conditions for storing buttercup squash, we examined the effectiveness of several storage methods and the quality of the squash under various storage conditions, including temperature (12 and $20^{\circ}C$) and relative humidity (20, 40, 60, and 80%). The spoiling rate of the squash was affected more by the storage temperature than the relative humidity, and the squash stored at $20^{\circ}C$ started to be deteriorated after 20 days of storage. At $20^{\circ}C$, soluble solid content gradually increased until 20 days of storage, and then it tended to decrease. The L-value had a tendency to increase with days of storage, and the a- and b-value also increased after 40 days. In addition, the color changes were great when the squash was stored at high temperature and high relative humidity. The total pectin content increased until 20 days at $20^{\circ}C$, and then it decreased, but less change was observed in the squash stored at $12^{\circ}C$. Overall, the results showed that storage at $20^{\circ}C$ after field curing resulted in excessive weight loss, color loss and poor eating quality, as well as a high level of decay (approximately 70%) after 40 days. However, the squash stored at $12^{\circ}C$ and 60% RH (relative humidity) showed less degreening and had a reduced level of decay, below 10%.

• Korean Journal of Remote Sensing
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• v.27 no.2
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• pp.163-170
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• 2011

In this paper, we analyzed the phase change of 5-triangular trihedral comer reflectors by using X-band Ground-Based Synthetic Aperture Radar (GB-SAR) system. Each reflector was set as a stationary target at a different distance from the system. We obtained total 123 full-polarization images during 40 hours continuously at 20 minute interval. Results of SAR interferometric analysis showed phase changes of maximum 2 radians and followed similar pattern with atmospheric data. Through a GB-SAR phase formula that includes refractive index in the air, we performed regression analysis for refractive index as a function of atmospheric humidity, temperature and pressure. As a result, refractive index of air in X-band showed relatively high coefficient of determination with humidity and temperature (0.72 and 0.76 on average, respectively) but not so with pressure (0.34). The refractive index of air in X -band changed by 3.14\;{\times}\;10^{-5}$ during the measuring time with a humidity range of 50% ~ 90% and a temperature range of $-1^{\circ}C$ ~ $9^{\circ}C$. We expect that a total expression of refractive index of air including humidity, temperature and pressure can be calculated when more extensive data would be collected at various atmospheric conditions.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.4
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• pp.1-7
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• 2003

습공기에 포함된 수증기가 상(Phase)변화를 일으킬 때 잠열이 발생하고 이 잠열은 익형 주위의 압축성 유동 상태량들을 변화시키므로, 이러한 열 증가가 유동에 끼치는 영향에 대하여 수치해석을 통하여 연구 수행하였다. 수치해석은 Rusak 과 Lee [1]가 최근에 연구 수행한 미교란 방법(small-disturbance approach)에 근거하여 이루어졌다. 고전적 핵 생성 모델과 작은 물방울 성장(droplet growth)모델을 이용한 이 방법에서는 비평형 균질 응축과정에서 일어나는 열 방출을 묘사한다. 응축에 의한 열전달, 압축성 유동의 운동에너지, 그리고 유동의 열적 상태량들 사이에서 일어나는 비선형 상호영향을 조사하고, 또한 주어진 문제를 지배가호 있는 상사 파라미터들을 제시하였다. 계산 결과들은 Euler 방정식을 사용하여 얻은 선행 수치계산들과 비교하여 잘 일치됨을 보였다. 상사법칙은 유동 동역학과 응축 상태량들이 상당히 비슷하게 거동하는 다양한 유동 형태들을 제안한다. 압축성 습공기 유동은 유체기계에 사용되는 익형들의 공력 성능을 증가시키는데 응용될 수 있다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.3
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• pp.347-352
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• 1999

The finite element formulation and simulation of drying process for ceramic electric insulators are investigated. The heat and moisture movements in green ceramics caused by the interaction of temperature gradient, moisture gradient, conduction, convection and evaporation are considered. The variations of temperature and moisture not only change the volume but also induce the hygro-thermal stress. The finite element formulation for solving the temperature and moisture distributions as well as the associated hygro-thermal stresses is derived. Using the computer code developed, the drying process of a ceramic electric insulator is simulated. Temperature distribution, moisture distribution, hygrothermal stress and deformed shape during the drying process are predicted.

• Environmental and Resource Economics Review
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• v.25 no.2
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• pp.277-297
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• 2016

This study is to analyze the effects of changing pattern of climate vaariables on total factor productivity of Korea manufacture industry. Changes in temperature, rainfalls and humidity which are the representative climate variables are used as main factors. Not only average values of the variables but those highest values are used as independent variables in the model, in order to consider the characteristic pattern of recent climate change, the high volatilities. The OLS results are unlike to previous literature that temperature and humidity had no significant impact on manufacturing productivity. An increase in the amount of precipitation was analyzed that impact negatively impacted. The analysis of panel data showed that temperatures and precipitation all that does not significantly affect the manufacturing. While the increase of the average humidity is shown to increase the total productivity of manufacture industry. In Korea, adaptation capability is important in determining the effects of climate change on productivity of manufacture industry.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.137-137
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• 2017

현재 상용화되어 있는 온실 환경제어시스템의 S/W 및 H/W는 서로 호환이 되지 않아 농민들이 원하는 맞춤형 복합 환경 제어시스템을 운영하는데 어려움이 있다. 따라서 본 연구는 다양한 제어알고리즘 및 장비를 적용시킬 수 있는 호환성이 향상된 온실 환경 제어인터페이스 모듈 성능평가를 목표로 한다. 센서 및 제어 인터페이스 모듈 성능평가를 위해 사용된 제어 시스템은 8 bit MCU가 적용된 전용 개발보드를 사용하였고, RS-232 통신 케이블을 사용하여 온실 환경 측정 데이터 값을 PC에서 수신할 수 있도록 하였다. 또한, 창개폐기, 환풍기를 사용하여 온실 내부 온/습도 환경조성을 하였다. 실험은 정오부터 제어장비를 작동시킨 후 1시간 간격으로 총 3시간 동안의 온실 내 온/습도의 변화량을 계측하였다. 3시간 중 1시간동안의 온/습도 값의 변화량을 계측한 결과 평균값은 각각 $33.21^{\circ}C$, 34.94%이었고 표준편차는 각각 $1.44^{\circ}C$, 2.74% 이었다. 제어 알고리즘은 단순한 ON/OFF 방법을 사용 하였고 총 2가지 제어장비를 사용하였으며 모두 정상 작동 하였다. 1시간동안 온실의 온도는 $30^{\circ}C{\sim}35^{\circ}C$사이를 유지하였으며, 습도는 30%~ 40% 사이로 최초 실험 목표였던 온실 내부의 온/습도 범위를 유지하였다. 이번 실험은 ON/OFF 방법의 제어 알고리즘을 사용하였지만 더욱 정밀한 온실 환경제어를 위하여 PID, 퍼지 제어 알고리즘을 추가하여 기상환경에 따른 제어범위를 더욱 세밀화 할 수 있도록 설계한다면 제어장비에 대한 효율성이 향상될 것이라 기대한다.

• Journal of Sensor Science and Technology
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• v.7 no.2
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• pp.83-89
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• 1998

$TiO_{2-x}$ thin film humidity sensors have been fabricated by sputtering method and their physical and hygroscopic characteristics have been investigated. The sputtering conditions and sintering conditions affect the sensor's sensitivity toward humidity. AES and SEM micrographs were taken for the analysis of crystal structures, surface morphology caused by adsorbed water vapour. $TiO_{2-x}$ humidity sensors showed negative impedance-humidity characteristics and the sensor which was fabricated by experimental condition 2(rf power of 200W) showed higher sensitivity and linearity than others. Then the slope of the sensor was about $0.794\;K{\Omega}/%RH$ and the response time of $TiO_{2-x}$ humidity sensors was about 2 min. for adsorption and about 3 min. for desorption at the operating temperature of $30^{\circ}C$.

• Applied Chemistry for Engineering
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• v.24 no.6
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• pp.593-598
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• 2013

In this study, we have evaluated the water absorption phenomenon of photoresist dry film, which is commonly used to build circuits on PCB (Printed Circuit Board) by photolithography, by using ATR-FTIR (Attenuated Total Reflectance-Fourier Transform Infrared). We have firstly observed significant change in fracture mode of dry film with respect to temperature and humidity, which we assumed the material transition from ductile to brittle. Secondly, we have established the process of absorption test for determining the diffusion coefficients of water into the dry film both with gravimeter and ATR-FTIR. We have successfully calculated the diffusion coefficients for each environmental conditions from the results which we achieved by gravimeter and ATR-FTIR. Compared to the gravimeter which is a conventional method for absorption test, the ATR-FTIR method in this study has been found to be very easy to use and have the same accuracy as gravimeter. Moreover, we are expecting to use the ATR-FTIR as an appropriate method to study the absorption phenomena related to any kinds of solvent and polymer system.

• Proceedings of the Korean Vacuum Society Conference
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• 2007.02a
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• pp.110-110
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• 2007

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2000.10a
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• pp.38-41
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• 2000