• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.12
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• pp.1245-1251
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• 2009

This paper describes the research on the non-eroding throat insert materials under condition of high-temperature, high-pressure, and long-burn time. C/SiC, CIT and W/$Y_2O_3$ were chosen and tested in thermal protection evaluation motor of burning time 20 seconds. From the test results, a heat resistance of W/$Y_2O_3$ was the most excellent among them, but was happened crack on material surface. Thermal reaction characteristics and heat resistance of these materials and feasibility of W/$Y_2O_3$ as throat material were ascertained.

• Journal of ILASS-Korea
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• v.18 no.1
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• pp.27-34
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• 2013

A preburner is one of the key components for a staged combustion cycle engine fueled by kerosene and Lox. Since it has oxygen rich combustion inside, temperature control is very crucial. The temperature of the exhaust gas should be low enough not to burn turbine blade and yet high to keep the efficiency high. In addition temporal and spatial deviations also managed strictly. Conventionally, the required average and maximum temperature are determined by engine system and the preburner should be developed to meet the criteria. Currently being developed preburner has 50K spatial temperature deviation requirement. It was estimated by numerical simulations and proven by tests. The numerical analysis were done with both supercritical condition and normal conditions. The tests results showed that the temperature deviations were less than expected, and the results from the test and simulations were well agreed when the supercritical conditions were considered. Above all, since the gas temperature created by the preburner is very stable with minimum deviation, the preburner developed can be used to drive a turbine and for gas-liquid combustion chambers.

• Transactions of the Korean Society of Automotive Engineers
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• v.1 no.2
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• pp.27-33
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• 1993

Using the solenoid driven gas injection valve, Hydrogen fuel supply system was made. It was attached to a single cylinder research engine and intake port injection type hydrogen fueled S.I. engine was constructed. Engine performance, emission characteristics, and abnormal combustion were studied through the engine test performed with the variations of fuel-air equivalence ratio and spark timing. Compared with gasoline, hydrogen burns so fast that cylinder peak pressure and temperature are higher and NO is emitted more at full load condition. IN the case of intake port injection type engine, COVimep becomes lower due to the well-mixing of air and fuel, and engine output is lower owing to the low volumetric efficiency. As fuel-air equivalence ratio goes up, the combustion speed increases, and COVimep decreases. NO emission peaks slightly lean of stoichiometric. As spark timing advances and fuel-air equivalence ratio goes up, the cylinder peak pressure and temperature become higher, so abnormal combustions take place easily.

• Journal of the Korean Society of Food Culture
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• v.23 no.1
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• pp.115-120
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• 2008

The dried persimmon was effective in caring an inflammation, an ulcer and a burn and preventing hypertension and arteriosclerosis. At the Jejungsinpyun. dried persimmons gruel was beneficial to stomach and intestine and toned down voice. Based on Jejungsinpyuns and Sikryochanyo, dried persimmons gruel was developed for modern people. To standardize the dried persimmons gruel, physical properties and consumer acceptability was examined. The procedures of dried persimmons gruel was to make dried persimmons juice after soaking dried persimmons with same volume water during 24 hr and blending. To decrease the astringent taste of dried persimmons, dried persimmons juice and water with cinnamon (2%) was mixed and simmered during 3 min. Dried persimmons paste with cinnamon was added and the gruel was boiled more during 5 min. dried persimmons gruel was completed. The dried persimmons gruel were divided of 5 groups consisted of each 10, 15, 20, 25, 30 g dried persimmons. As dried persimmons content increased, lightness, apparent viscosity decreased. Acceptability test indicated the sample of dried persimmons : rice ratio at 2 : 5 had the highest overall acceptability and flavor. Considered to each, the sample of the dried persimmons : rice ratio at 2 : 5 met the purpose of the study.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.1
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• pp.185-191
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• 2015

This paper suggest the safety class communication board in order to design the safety network of the nuclear safety class controller. The reactor protection system use the digitized networks because from analog system to digital system. The communication board shall be provided to pass the required performance and test of the safety class in the digital network used in the nuclear safety class. Communication protocol is composed of physical layer(PHY), data link layer(MAC: Medium Access Control), the application layer in the OSI 7 layer only. The data link layer data package for the cyber security has changed. CRC32 were used for data quality and the using one way communication, not requests and not responses for receiving data, does not affect the nuclear safety system. It has been designed in accordance with requirements, design, verification and procedure for the approving the nuclear safety class. For hardware verification such as electromagnetic test, aging test, inspection, burn-in test, seismic test and environmental test in was performed. FPGA firmware to verify compliance with the life-cycle of IEEE 1074 was performed by the component testing and integration testing.

• Journal of the Korean Solar Energy Society
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• v.28 no.4
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• pp.10-16
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• 2008

The fire resistance of thermal insulation and interior finishing materials is recently much emphasized after the fire accident at the Icheon Cold Store in January 2008. Three kinds of thermal insulation are used in buildings. They are Organic, Non-organic and cellulosic insulation. Organic insulation such as polystyrene foam board and urethane foam has high thermal resistance but it has no fire resistance. While non-organic insulation such as rockwool and glassfiber has high fire resistance, it has lower thermal resistance than organic insulation. Cellulose insulation is primarily manufactured from recycled newsprint or cardboard using shredders and fiberizers. Despite of its environmental friendliness and high thermal resistivity, its domestic use has not much increased because of the prejudice that paper can easily burn. However, the cellulose insulation as a product is about 80 wt.% cellulosic fiber and 20 wt.% chemicals, most of which are fire retardants such as boric acid and ammonium sulfate. It is required to secure its fire safety for more consumption as a building insulation in Korea. Therefore, this study investigates the fire resistance of Korean cellulose insulation according to the rate of fire retardant and finally presents the optimum rate of fire retardant in cellulose as building insulation. The fire safety test was conducted according to the ASTM C 1485-00. The test results indicate that above 18 wt% of fire retardant is necessary to secure the fire safety of cellulose insulation.

• The Journal of the Convergence on Culture Technology
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• v.7 no.2
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• pp.27-33
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• 2021

The purpose of this study was to investigate the influence of clinical nurses' sleep disorder, organizational support, and health promotion behaviors on professional quality of life. The subjects were 256 nurses working in hospitals in more than 200 and less than 300 beds hospital in B and G cities. The data were collected from September 4, 2017 to September 11, 2017. The collected data were analyzed by frequency analysis t-test, ANOVA, Scheffé test, Pearson's correlation coefficients, and multiple regression analysis using SPSS WIN 20.0. Burnout rate was 28.90± 4.00, burnout was associated with sleep disorder(r=-.321, p<.001), organizational support(r=-.321, p<.001), health promoting behavior(r=-,519 p<.001) showing a negative correlation. The factors affecting burnout were organizational support(β=-.113, p=.045), sleep disorder(β=-.129, p<.040), gender(β=-.131, p=.024), health promotion behaviors(β=-.423, p<.001) and the explanatory power was 32.2%. Based on these results, we aim to provide basic data for the development of various programs that can control burnout of nurses.

• 재활복지
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• v.21 no.2
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• pp.217-231
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• 2017

We have to consider two parts of the evaluation and treatment for the patients with head and neck burns. The primary consideration is swallowing function for nutrition supply for them and the next is speech function for efficient communication and aesthetic impression of them. The purpose of this study is to summarize the preliminary questions of Communication Screening Protocols which can help understand comprehensively on swallowing disorder, motor speech disorder and voice disorder of patients with head and neck burns. We divided the evaluation into 4 evaluation areas including 'oral mechanism', 'respiration/voice', 'articulation', and 'swallowing' by referring to overseas studies dealing with various communication disorders caused by burns, and prepared the final questionnaires by conducting the content validity verification by five expert (speech & language pathologist). The range of Content Validity Index was shown relatively appropriate with .50~.84. There was a conflict of opinions in experts whether the items in the areas of respiration/voice and swallowing may be appropriate, whereas there was no different view of the oral mechanism and articulation area. Through the different characteristics of communication difficulties of patients with head and neck burns, we expect it will be modified appropriately according to the patients through evaluation of burn patients by type and severity.

• Journal of the Korean Applied Science and Technology
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• v.29 no.4
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• pp.545-551
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• 2012

Due to the use of polymeric materials in construction materials, the fire combustion gases that occur in the fire are various. The one of combustion gases, HBr is measured to evaluate the toxicity of the combustion gases in the FTP Code Part 2, Standard NES 713 and Standard BS 6853. According to the MSDS, Inhalation of HBr gas especially cause burn, respiratory dysfunction, headache, etc. The people who are exposed to 50ppm of HBr gas, very irritant gas may also frequently result in both immediate death and post-exposure deaths due to pulmonary complications. In this paper, we conduct a research on the combustion toxicity of HBr gas hazardous test which is motility measurement of the mice exposed to the HBr standard gas comparing the biological analysis result.

• Journal of the Korean Society of Industry Convergence
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• v.20 no.2
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• pp.105-113
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• 2017

Recently the direct injection diesel engine is the most efficient one available for road vehicles, so this fundamental advantage suggests the compression injection diesel engine are a wise choice for future development efforts. The compression ignition diesel engine, with its bigger compression ratios if compared to the SI engine, offers a higher thermodynamic efficiency, also additionally the diesel engine with its less pumping losses due to the throttled intake charge as in a SI engine has higher fuel economy. But the largest obstacle to the success of this engine is meeting emission standards for Nitric oxides and particulate matter while maintain fuel consumption advantage over currently available engines. Thus its use should be largely promoted, however, diesel engine emits more Nitric oxides and particulate matter than other competing one. There has been a trade-off between PM and NOx, so efforts to reduce NOx have increased PM and vice versa, but trap change this situation and better possibility emerge for treating NOx emission with engine related means, such as injection timing, equivalence ratio, charge composition, and engine speed. The common rail direct injection system is able to adjust the fuel injection timing in a compression ignition engine, so this electronically controlled injection system can reduce the formation of NOx gas without increase in soot. In this study it is designed and used the engine test bed which is installed with turbocharge and intercooler. In addition to equipped using CRDI by controlling injection timing with mapping modulator, it has been tested and analyzed the engine performance, combustion characteristics, and exhaust emission as operating parameters.