• 한국감성과학회:학술대회논문집
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• 한국감성과학회 1998년도 추계학술발표 논문집
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• pp.88-93
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• 1998

The purpose of this study was to examine theory about indoor thermal comfort-environment as well as to determine thermal sensation and physical responses for men in summer and winter indoor environment, under various air temperature and relative humidity, with male university students. Subjective Evaluation, Heart rate(Electrocardiogram, ECG), Electroencephalo gram(EEG) were examined. We found that comfort of people was achieved at SET*. 24.7$^{\circ}C$, -0.82${\alpha}$-wave) both in summer and in winter.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.179-182
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• 2007

COMS (Communication, Ocean and Meteorological Satellite) is a geosynchronous satellite and has been developing by KARI and Astrium for Ka-band communication, ocean observation and meteorological observation. COMS Chemical Propulsion System (CPS) uses a bipropellant propulsion subsystem, which is applied for transferring COMS from GTO to GEO (mission orbit) and implementing station-keeping manoeuvres. In this paper COMS CPS is briefly introduced for understanding. A few of mathematical thermodynamic modelings of bipropellant propulsion system in literatures are reviewed and authors has studied those models for developing a computer program, which predicts variations of thermodynamic properties such as temperature and pressure histories in the helium pressurant tank, MMH propellant tank and NTO propellant tank during LAE firing and on-orbit manoeuvrings. The CPS thermodynamic model may be used to compute pressurant and propellant masses and to size tank volumes.

• Parasites, Hosts and Diseases
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• 제31권2호
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• pp.91-98
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• 1993

To determine the infectivlty and maturity of nletacercanae of Parqgonimur westermani after keeping at low temperature for a long period, 45 mice and 45 rats were each infected with 20 metacercariae which were kept at $4^{\circ}C$ for 8 to 234 days. The worm recovery in mice increased with age of worm and reached a peak of 32% at 41-50 days and then decreased with age. The rate In rats first decreased to a lowest point of 6% at 71-100 days and then Increased with age. In 42 infected mice and 41 infected rats, 187 immature worms (183 tiny and 4 Juvenile ones) and 190 worms (164 tiny, 19 Juvenile and 7 mature ones) were recovered respectively. Two wormcysts with eggs only and 8 empty wormcysts were also found In the rats. In addition, the frozen metacercanae can still develop to mature worms in SD rats.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2005년도 추계학술발표논문집
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• pp.127-139
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• 2005

It is very difficult to export the fresh agricultural products to long distant countries such as America and EU without any damage. Fresh exporting products would be met very hazardous environments such as hot and cold weather, heavy trembles with rolling and pitching. Therefore, care should be taken on tight fastening the products inside the container and keeping the designated temperature and relative humidity. The physical strength of outer box should be applied differently because each agricultural product has its own character for packaging. There have been many agricultural products researches for export packaging to the U.S.A. so far. However they have never got desirable results which enough to apply it in real. The main purpose of this research is to develop optimum compressive strength of corrugated fiber board box which would be used to American export packaging of fresh agricultural products such as perilla leaves, green red pepper and spinach.

• 한국식품조리과학회지
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• 제19권1호
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• pp.24-33
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• 2003

The purpose of the study was to investigate the HACCP systems of contract foodservice establishments by surveying HACCP plans and prerequisite programs from the twelve HACCP-implemented contract foodservice establishments appointed by KFDA. All the subjects (100%) appeared to develop HACCP plans with their own hazard analysis. Except the two giving no response, it turned out that two establishments had 2 CCPs (20%), four had 4∼5 CCPs (40%) and another four had 9 CCPs (40%). Especially, 'cleaning and sanitizing of raw vegetables and fruits (90%)' and 'cooking (temperature) (100%)' were monitored as CCPs by all the subjects. Only one subject (8.3%) answered that continuous monitoring was not conducted. But the verification, record keeping and internal audits were maintained by all the subjects (100%). Most of the surveyed foodservice establishments maintained various prerequisite programs enough to back up HACCP system.

• 태양에너지
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• 제11권2호
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• pp.34-40
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• 1991

Thermal stratification enhancement for the higher extraction efficiency of hot water storage tank was experimentally studied with transparent fiber glass cylindical tank($350{\ell}$, D=516mm, H=1680mm). Height to diameter ratio (H/D =1,2,3), flow rate(Q= 8,10,12LPM), inlet-outlet temperature differences(${\Delta}T=20,25,30^{\circ}C$), and geometry of inlet-outlet port were the parameters. In particular, three kind of distributors were used for geometry of inlet-outlet port. As a result, it was possible to get extraction efficiency of 95% by using the distributor having variable diameter but keeping a constant diameter of perforation. So it is recommendable to design the distributor so that the main pipe decrease in diameter toward the dead end.

• 설비공학논문집
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• 제13권10호
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• pp.993-1001
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• 2001

Experimental investigation on the performance of dual-evaporator refrigeration system with an ejector has been carried out. In this study, a hydrofluorocarbon (HFC) refrigerant R134a is chosen as a working fluid. The condenser and two-evaporators are made as concentric double pipes with counter-flow type heat exchangers. Experiments were performed by changing the inlet and outlet temperatures of secondary fluids entering condenser, high-pressure evaporator and low-pressure evaporator at test conditions keeping a constant compressor speed. When the external conditions (inlet temperatures of secondary fluid entering condenser and one evaporator) are fixed, results show that coefficient of performance (COP) increases as the inlet temperature of the other evaporator rises. It is also shown that the COP decreases as the mass flaw rate ratio of suction fluid to motive fluid increases. The COP of dual-evaporator refrigeration system with an ejector is superior to that of a single-evaporator vapor compression system by 3 to 6%.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 추계학술대회 논문집
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• pp.474-480
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• 2002

Aspheric optical lenses and mirrors are widely used in recent. It is more difficult to manufacture and measure the aspherical optics compared to conventional spherical ones. The interferometric optical test is common for the measurement of spherical optical surface. But the application of the interferometry to the measurement of aspheric surface is difficult because it needs a precise null corrector and very careful environmental conditions such as keeping constant temperature, humidity, atmospheric pressure and vibrations. To enhance productivity of optics manufacturing on-machine measurement and correction has been developed in this study. For practical applications, robustness of the measurement method to environments is more important. For the purpose an optical OMM(On-Machine Measurement) system has been developed using Shack-Hartmann test which has robustness to the environment. The wavefront has been reconstructed from the measured data using the primary aberration polynomial function by least square fitting. The measured result of the developed only system gives the maximum deviation only in 200 nm from the result measured by a commercial Fizeau interferometer Wyko 6000.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(III)
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• pp.377-382
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• 2003

In tread braking of freight cars, braking force is produced by the friction between the wheel and the braking shoe. Friction coefficients such as the brake power, weight variation and brake shoe types should be sensitively treated as the design parameters. The conditions of the car, empty and weighted, should also be taken into consideration in brake force design and the control of brake force has some limitations in terms of the brake system design so that the brake materials selection should be considered as important measures to solve that difficulties. Friction characteristics of brake materials should remain within the range of maximum and minimum value and the friction performance should remain stable regardless of braking time and temperature. This study presented an experimental evaluation method to secure optimum braking performance by keeping safe braking effect and braking distance by the friction coefficient of the brake shoe of the freight cars.

• International Journal of Air-Conditioning and Refrigeration
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• 제10권4호
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• pp.201-210
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• 2002

Experimental investigation on the performance of dual-evaporator refrigeration system with an ejector has been carried out. In this study, a hydrofluorocarbon (HFC) refrigerant R134a is chosen as a working fluid. The condenser and two-evaporators are made as concentric double pipes with counter-flow type heat exchangers. Experiments were peformed by changing the inlet and outlet temperatures of secondary fluids entering condenser, high-pressure evaporator and low-pressure evaporator at test conditions keeping a constant compressor speed. When the external conditions (inlet temperatures of secondary fluid entering condenser and one of the evaporators) are fixed, results show that coefficient of performance (COP) increases as the inlet temperature of the other evaporator rises. It is also shown that the COP decreases as the mass flow rate ratio of suction fluid to motive fluid increases. The COP of dual-evapo-rator refrigeration system with an ejector is superior to that of a single-evaporator vapor compression system by 3 to 6%.