• Journal of the Korean Society of Propulsion Engineers
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• v.11 no.6
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• pp.42-49
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• 2007

In this study, we analyzed flow characteristics of micro-nozzles for basic research to develop micro propulsion system. Cold gas propulsion system was used, and micro-nozzles having nozzle throat diameters of 1.0, 0.5, 0.25 mm were fabricated with EDM method. Thrust was measured through the use of plate-spring and strain gage based thrust measurement system, and flow characteristics of micro-nozzles were analyzed under ambient condition and vacuum condition. We used argon and nitrogen gases as propellant, and compared experimental results with CFD analysis. From the result, we verified the flow losses of viscosity and back-pressure caused by minimization of nozzle.

• Journal of Energy Engineering
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• v.11 no.2
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• pp.178-185
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• 2002

The object of this paper is to investigate the effects of early fuel evaporators on cold driveability of gasoline passenger cars. Experiment has been carried out for the assessment cold start performance and cold driveability. And fuel consumption rate, emission and cylinder pressure were measured. On the base of combustion pressure of cylinder, rate of heat release, cumulative heat release amount and burned mass fraction are evaluated. The results show that fuel consumption rate is increased by 17.7%, monoxide and hydrocarbon were reduced by 23% and by 45% respectively, fluctuations of indicated mean effective pressure and maximum combustion pressure were increased by 4∼6%, fuel consumption rate per power was improved by 0.2∼2.3%. These are caused by the fact maximum heat release period and main combustion period are getting short.

• Journal of Food Hygiene and Safety
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• v.16 no.1
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• pp.37-40
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• 2001

Recently, consumer's demand for natural preservatives is increasing because of residual toxicity, mutagenicity and etc. of synthetic preservatives and th study of natural preservatives is being done. In this study, antimicrobial activity of spices was investigated. Fungi occurred in bread and d noodle without mustard after 3days and 4days, respectively. However, they didn't occured in bread and noodle with mustard ball. Temperature of the water used in mixing-up mustard powder didn't affect antimicrobial activity of mustard. Fungi occurred in bread with cinnamon, Japanese pepper or horseradish after 4days, 4days or 6days, respectively. However, there wasn't the occurrence of fungi in bread with mustard after 8days, yet. Mustard and horseradish of extracts by water of spices had a strong antimicrobial activity. But the extracts by ethanol had 1ow antimicrobial activity.

• Journal of the Korean Society of Hazard Mitigation
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• v.5 no.2 s.17
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• pp.45-56
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• 2005

Cloud meteorological properties over Daegwallyeong mountain area were analyzed for experimental cloud seeding which related to a feasibility study of fog modification. The cloud seeding for fog modification has been refocused to using hygroscopic chemical to dissipate warm fog. In this study, the statistics of fog observations were analyzed and discussed. Fog properties mostly showed the Summer warm fog, the early morning occurrences before to 6 o'clock AM, and 7 to 9 o'clock dissipation in the statistics. In the Spring and Winter season an easterly wind produced cold fog which is good applied with AgI seeding agents. Extrapolation of these results suggests that the suitable seeding method and material for fog modification will be introduced from the actual seeding experiments in the cold and warm fog.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.13 no.3
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• pp.1-8
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• 2017

Variable refrigerant flow (VRF) systems have recently attracted attention in many countries due to a variety of advantages over conventional system. Especially, the water-cooled VRF heat pump, including geothermal heat pump, is a system that accurately controls the flow rate of refrigerant for the improved efficiency under part load operation. This paper describe the process of generating the cooling and heating energy performance curve coefficients and performance expressions for modeling water cooled VRF system using EnergyPlus. Through this study, the process for generating performance curves can be implemented into EnergyPlus or other comparable building energy analysis tools for the long-term evaluation of heat pump under dynamic conditions.

• Journal of Korean Clinical Nursing Research
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• v.21 no.3
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• pp.355-365
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• 2015

Purpose: The purpose of this study was to evaluate nursing protocols for superficial cryotherapy in different medical institutions. Methods: The study was conducted with a cross-sectional descriptive design. The medical institutions including general hospitals, hospitals, and geriatric hospitals were randomly selected. A total of 435 nurses from 126 institutions completed a questionnaire. Data were collected from December 2014 to June 2015. Results: Forty-two institutions (39.5%) had nursing protocol for cryotherapy. The nurses reported that durations of cold application were 2 minutes to 5 hours. Frequently used cold therapy devices in order of frequency were frozen gel packs, ice packs, and frozen IV fluid bags. There were variances in the duration of cold application according to the types of institution ($x^2=7.78$, p=.020) and nursing units ($x^2=26.42$, p<.001). In addition, intervals of cold application were different according to the nursing units (x=12.23, p=.032). There were differences in cold application instruments by regional groups (x=70.38, p<.001). Most of the nurses (95.6%) responded that national nursing protocol for superficial cryotherapy were needed. Conclusion: There were difficulties in providing consistent nursing interventions because of the practical differences and absence of evidence-based guidelines for cryotherapy. The researchers recommend that basic studies with various instruments be conducted and proper nursing protocols be developed for cryotherapy.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.5
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• pp.328-335
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• 2010

The purpose of this study is to make an analysis of influence on the cooling capacity and COP of a desiccant cooling system with a regenerative evaporative cooler when a direct evaporative cooler was applied to the inlet of regeneration process of this system. We used cycle simulation in order to analyze the performance of this system. From the cycle simulation, we knew that the optimal rotation time of desiccant rotor was between 160s and 220s and hardly ever affected cooling capacity of desiccant cooling system when this system was operated at the outdoor air condition of $35^{\circ}$ and 40% RH and low regeneration temperature of $60^{\circ}$. Also there was optimal area ratio of regeneration to dehumidification between 0.7 and 1.0. Our results showed that it had a small effect on the system’s cooling capacity to install direct evaporative cooler at the inlet of regeneration process.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.spc1
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• pp.196-199
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• 2005

This study was conducted to find out the effect of quality of water for wasabi growth by the relationship of quality of water and plant growth. In dissolved contents of water, water of lime area was higher than basalt area at $NO_3$, Cl, Ca, and Mg. In the change soil hardness and water temperature, basalt area was lower than lime one, during wasabi cultivation. Growth characteristics and yield were higher in basalt area than lime one. The weight of rhizome in basalt and lime was 585 kg/10a, 4183kg/10a, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.3
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• pp.281-285
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• 1997

Essential oil extracted by solvent, n-pantane and diethyl ether for 2 hours was 0.1∼0.5％ in Wasabia japonica Mastum. and it was showed the highest content in root and the lowest content in petiole. Allylisothiocyanate detected by gas chromatography contained in all of the plant part in wasabi. Its content in rhizome was 0.687∼1.339mg /g FW showing the highest content in rhizome. Allylisothiocyanate content was varied from culture site, variety and position of rhizome in wasabi.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.129-129
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• 2011

냉음극 변압기 전원 소스를 이용하여 저진공에서 플라즈마를 발생시키는 시스템을 개발하였다. 또한 이 장치를 이용하여 도핑된 산화막 증착 기술을 연구하였다. 이 때 도핑 전구체는 액체 소스였으며 이를 기화시켜 사용하였다. 특히 p 타입이 도핑된 이산화규소 박막 증착을 상온에서 실시하였다. 공정 압력은 400~1,000 mT였으며, 전압은 약 1,100~2,100 V 범위에서 조절하였다. 증착된 박막은 박막 두께와 홀 측정을 실시하였다. 홀 측정을 위한 인듐 금속 접합을 400 C에서 실시하였다. 결과를 요약하면, 플라즈마 공정 압력이 400에서 1,000 mTorr로 증가함에 따라 박막 증착 속도는 약 240~440 ${\AA}$/min이었다. 또한 증착된 p-SiO2의 벌크 농도는 같은 압력 증가에 따라 약 $1.2{\times}10^{19}$에서 $6.5{\times}10^{18}/cm^3$으로 절반 정도 감소하였다. 그에 따라 도핑된 산화막의 비저항은 $~1.4{\times}10^{-3}$에서 $2.5{\times}10^{-3}{\Omega}{\cdot}cm$로 증가하였다. 홀 이동도는 약 380~400 $cm^2/V{\cdot}s$를 유지하였다. 또한 전압이 1,100 에서 2,100 V로 증가함에 따라 산화막의 증착 속도는 약 330에서 410 ${\AA}$/min으로 증가하였다. 그러나 전압이 증가해도 벌크 농도는 약 8,9~$6.6{\times}10^{18}/cm^3$의 범위였다. 보다 자세한 결과는 발표를 통해 설명할 것이다.