• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2001.11a
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• pp.143-143
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• 2001

• Tribology and Lubricants
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• v.35 no.4
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• pp.206-214
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• 2019

This study investigates alternative refrigerants and refrigerant oils as well as the tendency of protecting the global environment in view of automobile air-conditioning systems. Since decades, the R12 refrigerant is not used in automobile air-conditioners because of the ozone depletion potential (ODP) problem, and for the last 20 years, the ODP-free R134a refrigerant is leading the new automotive air-conditioning market. However, owing to its high global warming potential (GWP), the R134a refrigerant use in automobile air-conditioning system is also prohibited by law, and alternative refrigerants with a low GWP need to be proposed. Therefore, recently, the application of R1234yf, R152a, or other alternative refrigerants has started worldwide. By contrast, natural refrigerant R744 was introduced in the market several years ago by VDA (Verband Der Automobilindustrie), which is a German association in the automotive industry. This study also deals with refrigerant oils. For a long time, polyalkylene glycol (PAG) oil has been traditionally used with automobile air-conditioners, and polyolester (POE) oil is suitable for HEV, PHEV, and EV air-conditioning systems, where it is used by the electrically driven compressor owing to its excellent electrical insulation properties. Finally, PAG is an excellent lubricant for all the R134a, R152a, R1234yf, and R744 refrigerants, and has the advantage that it can be applied rapidly to alternative refrigerant air-conditioning systems.

• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.433-438
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• 2005

An AHX(Accumulator Heat eXchanger) consists of a commercial accumulator and an inner heat exchanger located inside of the accumulator. The AHX is used in multi air-conditioners to assure the liquid-phase refrigerant entering into the expansion device. This purpose is achieved by heat transfer between the refrigerant leaving the evaporator and the refrigerant leaving the condenser. In this study, the effects of AHX on the performance of a refrigeration system using H-22 were measured and the test results were analyzed. The operating characteristics of the refrigeration system with the installation of AHX were quite different from those without the installation of AHX. Therefore, it is required to find an optimum refrigerant charging amount and optimum operating conditions, when AHX is installed in the refrigeration system with an fixed area expansion device such as a capillary tube.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.29 no.9
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• pp.70-74
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• 2000

소형에어컨의 대부분은 2004년까지 에너지절약법으로 정해진 목표기준을 달성하도록 의무화하고 있다. 또 오존층보호를 위해 신냉매로의 전환도 필요한 바, 본 보고에서는 소형에어컨의 에너지절약 기술과 신냉매 대응기술에 관하여 소개한다. 그밖에 에너지절약법의 목표기준을 달성하기 위해서 필요한 향후 연구과제에 대해서 기술한다.

• Proceedings of the SAREK Conference
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• 2004.06a
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• pp.60-60
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• 2004

• Korean Journal of Clinical Laboratory Science
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• v.49 no.4
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• pp.435-438
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• 2017

Nontuberculous mycobacteria (NTM) contains M. avium-intracellular complex (MAC), M. fortuitum, M. chelonae, M. abscessus, M. kansasii, etc., which causes infections in swine, poultry, and other animals. These bacteria are opportunistic pathogens that can contaminate people, and in doing so, cause various social economic problems. This study proved that NTM are also present in air conditioners of multiuse facilities in frequently visited populated areas. The results of this study are meaningful because they showed that pathogenic microbes can live in the surroundings and cause diseases to people with impaired immunity. This study used the AFB stain, L-J medium culture, and PCR method for the detection of MTB and NTM in air conditioner dust. MTB was not detected in any of the collected samples, while NTM was detected in 2 out of 40 samples (5%). Most people living in the modern environment cannot avoid being exposed to air conditioners so special attention is needed for sanitary inspections and the management of air conditioners. Moreover, it is important to study NTM through various individuals, accumulate the related data and establish the methods and standards of hygiene management system to reduce NTM infections in public areas. Moreover, it would be necessary to identify the precise species of NTM through DNA sequencing and evaluate the effects of NTM on the pulmonary tuberculosis in immunodeficiency patients.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.688-689
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• 2009

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.456-459
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• 2000

Due to cost-effective and compact system design IPM-based inverters are now being seen as an attractive alternative to conventional discrete-based inverters technique for low power ac drives in particular such as washing machines refrigerators and air-conditioners. Fairchild-IPM newly developed in order to provide the advantages of the lowest cost and better performance is discussed and its specification is given.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.11a
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• pp.129-133
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• 2000

Vapor oil fer radiator fm press in heat exchangers of air conditioners is carefully considered as the cooling performance can be affected by the residual vapor oil on the surface of radiator fin after fin press working. In this work, vapor oil for radiator fin press was developed in consideration of several properties such as physical characteristics, the rate of volatility, hazardous properties and material compatibility. In addition, it was confirmed that radiator fin press workability adopting the vapor oil and the cooling performance of air conditioner using the radiator fin were good.

• The Journal of Korean Academic Society of Nursing Education
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• v.3 no.2
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• pp.150-162
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• 1997

The purpose of this study is to examine hospital noise level and discomfort due to noise. The subjects were 156 patients from University hospital in Taegu. The data was collected from April 10 to May 14, 1997. The collected data were analyzed by SPSS program using percentage, paired t-test, ANOVA, and Pearson Correlation Coefficient. The results were as follows ; The mean score of noise level was 1.62. There was no statistically significant difference in noise level between day and night. Patients perceived higher noise in the categories of conversation of visitors, conversation of care providers, noise of air conditioners, and the conversation of nearby patients than others during the day. Patients perceived higher noise in the categories of noise of air conditioners, conversation of visitors, conversation of care providers, and telephone ringing than others during the night. There were no statistically significant differences in noise level among the 4 wards during the day or night. Discomfort was due to the forementioned noise, categories of high scores were sleep disturbed, irritated, not so bad or not noisy, and noisy. To avoid noise, the subjects coped by putting on a quilt, going out, sleeping, opening or closing the window or door, and plugging ears. These results indicated that hospital noise have a negative influence on patients' health. So noise levels should be reduced in hospitals.