• 한국자동차공학회논문집
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• 제12권5호
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• pp.1-11
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• 2004

In order to recognize thermal efficiency and power improvement in case that diesel cycle is turned into diesel-atkinson cycle, the fuel-air diesel-atkinson cycle considered gas exchange process is analyzed non-dimensionally and thermodynamically. As a result, in case of diesel-atkinson cycle, as expansion ratio is increased, thermal efficiency and mean effective pressure is increased and it has maximum value at Rec=1. When diesel cycle is turned into diesel-atkinson cycle by late intake valve closing timing, thermal efficiency and power is decreased because of the decline of effective compression ratio and intake airflow, but it could be compensated by increase of compression ratio or super-charged. In case compression ratio is compensated, Rec appears 1 around 100$^{\circ}$ ABDC, and it is expected that thermal efficiency is enhanced by 14.3% compared with conventional diesel cycle. In case compression ratio and intake airflow are compensated simultaneously, super-charged pressure is demanded 2.06bar at Rec=1 and it is more efficient when only compression ratio is compensated in the view point of thermal efficiency.

• The Journal of the Acoustical Society of Korea
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• 제24권3E호
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• pp.87-89
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• 2005

The acoustical sources of intake and exhaust systems in fluid machines are often characterized by the source impedance and strength using linear frequency-domain modeling. In the case of the sources which are nonlinear and time-variant, however, the source parameters were sometimes incorrectly obtained. In this paper, the source model and direct measurement technique are modified in order to evaluate the effect due to nonlinear and periodically time-varying source character as well as the linear property of the reflectivity of in-duct fluid machine source. With a priori known kinematical information of the source, the types of nonlinear time-variant terms can be presumed by a simple physical model, in which there is practically no restriction on the form of the model. The concept of source impedance can be extendable by introducing the linear frequency response function for each nonlinear or time-variant input. Extending the conventional method and adapting the reverse MISO technique, it is possible to develop a direct method that can deal with the nonlinear time-variant source parameters. The proposed direct method has a novel feature that there is no restriction on the probability or spectral natures of the excited sound pressure data. The present method is verified by the simulated measurements for simplified fluid machines. It is thought that the proposed method would be useful in predicting the insertion loss or the radiated sound level from intake or exhaust systems.

• 한국식품과학회지
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• 제26권5호
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• pp.616-621
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• 1994

한국인을 위한 식품중 유해성분의 기준설정 및 안전성 평가에 필요한 식품계수를 제안하기 위하여 $1986{\sim}90$년에 걸쳐 국민영양조사에 의한 식품섭취량과 식품수급표에 의한 공급량 자료로부터 농축산식품 원료에 대한 식품 종류별 섭취량을 최적화 하였다. 농축산물의 1인당 1일 평균 섭취량은 1.0kg으로 조정하였으며 곡류 422g, 감자류 29g, 두류 17g, 견과종실류 5g, 과일류 97g, 채소류 300g, 육류 49g, 난류 20g, 우유류 72g 이었다.

• 한국식품과학회지
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• 제27권4호
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• pp.618-624
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• 1995

우리나라에서 식품중 농약잔류 허용기준의 적합성을 평가하고 Codex 기준의 수용 가능성을 검토하기 위하여 허용기준치와 한국인의 식품계수 만을 적용한 농약성분의 이론적 최대섭취량을 계산한 다음 ADI 값과 비교하였다. 국내에서 허용기준이 설정된 105개 농약성분의 ADI 대비율은 대부분이 80% 이하 수준을 유지하고 있으나 ADI를 초과하는 농약은 13개 성분이었다. 한편 Codex 기준이 있는 82개 농약성분에서 ADI를 초과하는 농약은 20개 성분에 이르고 있다. 한국기준 또는 Codex 기준에서 ADI를 초과하는 22개 성분에 대해서는 그 원인을 지적하였으며 안전마진 확보를 위한 대책이 마련되어야 할 것이다.

• 수산해양교육연구
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• 제27권4호
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• pp.1075-1083
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• 2015

The purpose of this study consists in analyzing the reality of processed food intake by students in different educational environments such as fisheries maritime high schools and general high schools and their awareness of food additives and investigating the reality of nutrition education. In order to achieve this purpose, we selected a total of 400 students as the subjects of this study from fisheries high schools located in Busan, Incheon, Gyeongbuk, Chungbuk and Jeonnam and general high schools located in Busan, Gyeonggi and Jeonnam. The findings of this study are summarized as follows. First, when analyzing the reality of fisheries Maritime and general high school students' processed food intake, in terms of the gender difference, the female students indicated a higher processed food intake frequency than the male students and in terms of the school types, the fisheries Maritime and general high school students showed an almost similar processed food intake frequency. Second, seeing that most female and male students were aware that the food additives were unsafe substances. Third, when analyzing the reality of nutrition education, there were more students who had not received a nutrition education than the students who had received a nutrition education.

• 한국수소및신에너지학회논문집
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• 제21권2호
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• pp.98-103
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• 2010

In order to develop two-stroke free-piston hydrogen engine to obtain high thermal efficiency and low emission, backfire occurrence have to be prevented. In this research, backfire characteristics are analyzed as functions of the intake valve opening timing and compression chamber pressure under piston by using RICEM (Rapid Intake Compression Expansion Machine) that has reverse uni-flow scavenging. As the result, reverse uni-flow scavenging is advantage about back fire. but, it exists suitable intake valve opening timing and its timing become known that equivalence ratio 1 retard until the piston rises. Also, To rise chamber pressure of lower piston, this does not cause backfire occurs in equivalent ratio 0.6 observed back fire. Therefore, 2cycle hydrogen fueled free-piston engine is undesirable scavenging compression by compressing the piston.

• 한국자동차공학회논문집
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• 제14권5호
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• pp.121-129
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• 2006

An Intake Port of SI engines plays a key role on improving engine performance by maximizing full load volumetric efficiency or by optimizing in-cylinder air motion. However, designing an intake port has been usually performed based on port experts' experience and know-how, which means that analytical analyses are relatively insufficient. In this paper, port design parameters which decide an overall port shape were defined in order to correlate them relevantly with flow test results accumulated so far. Test species were composed of all twenty eight SI engines which cover major engine displacements from 1,000cc to 4,000cc. First, they were tested on a steady state flow test rig to find out their flow coefficients. Secondly, those flow coefficients were analyzed based on the port design parameters measured from the engines. The most effective parameters were port height, valve head diameter, and the ratio of port size and cylinder bore diameter. The final correlation equation could predict flow coefficients within 2% deviation.

• 공학기술논문지
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• 제11권4호
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• pp.253-257
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• 2018

Exhaust gas from the combustion of automobiles adversely affects the human body and even pollutes the atmosphere. This study investigated the influence of exhaust gas change on intake manifold using the nozzle. First, the flow analysis was performed using the 3D flow analysis program. When the nozzle inlet air velocity increased, the average air velocity in the nozzle diameters of ${\Phi}2.5$ and ${\Phi}5$ increased 37.3% and 31.9% respectively at the intake manifold outlet. As the nozzle inlet air velocity increased, the maximum flow rate of air increased to 42.2% and 32.6%, respectively at nozzle diameters of ${\Phi}2.5$ and ${\Phi}5$. In order to verify the analysis results, experiments on the exhaust gas were performed in the engine simulation system. As the nozzle inlet velocity increased, HC values decreased by 42.4% and 31.4% at nozzle diameters of ${\Phi}2.5$ and ${\Phi}5$, respectively. And CO values decreased by 40.7% and 31.1% at nozzle diameters of ${\Phi}2.5$ and ${\Phi}5$.

• 식품보건융합연구
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• 제7권3호
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• pp.33-40
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• 2021

The purpose of this study was to investigate the effects of turmeric intake and weight training on blood alcohol concentration, liver enzyme levels of and their effects on health promotion in adult males. There was no significant difference of taking turmeric powder combined with weight training exercise on blood alcohol levels in adult men who consumed alcohol on a regular basis. There was also no change on the change of body composition. The results were collected from elite athletes that had spent more than 10 years in their respective sports so it is difficult to observe any significant results from 8 weeks, short-term exercises of 1RM 70~80%, 3 times per week. In the next study, it is necessary to divide the subjects into more diverse groups and subject them by varying amounts of turmeric intake, exercise, etc., in order to fully study and understand the effects on blood alcohol level, change, and health promotion. Consequently, this study demonstrated there were no significant differences in the effects of continuous drinking habits of adult men's turmeric powder intake and weight training exercise on changes in GOT, GPT, γ-GTP, and blood alcohol concentrations. Moreover, health improvements themselves didn't affect changes in body composition.

• 한국식생활문화학회지
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• 제21권1호
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• pp.8-16
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• 2006

This study was performed by questionnaire to investigate the preference and intake frequency of Korean traditional commercial beverages. The subjects were consisted of 320 participants in Daegu and Kyungpook area. 'Chain market' scored 49.4% as purchasing place of traditional beverages. 'Tea bag' scored 31.6% as the favorite package of traditional beverages. On the reasons of drinking traditional beverage 'good for health' scored the highest with 31.3% respondents, followed by 'good smell' with 14.4%. Coffee and traditional tea were the choice of beverage after having a rich meal and on occasion of entertaining guests. The favorite foods in ordinary days were 'tea', 'alcohol', 'ice cream', 'nuts' and 'cookie'. More than thirty percent of the respondents, both male and female, raised the need of improvement in taste of traditional beverage. In the intake frequency, Korea traditional beverages obtained 1.80 points as a whole. 'Green tea' scored highest(3.40points) while 'mulberry-leaf tea' received the lowest score of 1.31 points. The preferred Korean traditional drinks were 'greed tea', 'shick hae', 'citron tea', 'misitgaru', 'maesil tea', 'rice tea' in the order. On the other hand, the preference for 'mulberry-leaf tea', 'boxthom tea', 'ginger tea', 'chrysanthemum tea' and 'omija tea' was very low. The people who are on twenties preferred 'shick hae', 'honey tea', 'citron tea', 'black tea' and 'misitgaru' more than the other generation.