• 한국자동차공학회논문집
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• 제7권9호
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• pp.20-27
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• 1999

The proportion of diesel vehicle is very high in this country . PM and NOx emitted from diesel-posered vehicle is severely ;affecting to be air quality . Especially, diesel particulate matters(DPM) including black smoke are hazardous air pollutants to human health and environment. In order to reduce the exhaust emissions from diesel engines, it is necessary to analyze the characteristics of exhaust emissions from diesel engines in various driving conditions. Recently, there are occasion to increase the fuel consumption rate to engine power up. So, in this study we have tested a diesel engine detached from in use -diesel vehicle and analyzed exhaust emission by driving condition and fuel dispersion rate. From this results, we will prepare the comprehensive management plan for exhaust emissions from diesel vehicles and contribute to the improvement of air pollution in urban area.

• 한국공작기계학회논문집
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• 제12권6호
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• pp.97-103
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• 2003

Currently, due to serious increase of pollution scones, lots of technology has been involved to reduce exhaust gas in diesel engine. But the amounts of exhaust gas can not be decreased somehow due to the increase of diesel vehicles. Moreover, emission standards of each counties are being stringent in advanced countries such as USA and Europe. In the near future, sulfur contents in fuel must be essentially reduced f3r health and environment because sulfur can basically reduce exhaust gas. Therefore, when will be applied to Bio-diesel and ULSD, they could reduce sulfur contents of fuel without aftertreatment and might conform the influence of engine performance, emission, smoke and fuel consumption.

• 동력기계공학회지
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• 제8권1호
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• pp.18-23
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• 2004

The direct injection diesel engine is one of the most efficient thermal engines. For this reason DI diesel engines are widely used for heavy-duty applications. But the world is faced with very serious problems related to the air pollution due to the exhaust emissions of diesel engine. So, that is air pollution related to exhaust gas resulted from explosive combustion should be improved. Exhaust Gas Recirculation(EGR) is a proven method to reduce NOx emissions. In this study, the experiments-were performed at various engine loads while the EGR rates were set from 0% to 20%. The emissions trade-off and combustion of diesel engine are investigated. Hot and cooled EGR are achieved without cooling and with cooling respectively. It was found that the exhaust emissions with the EGR system resulted in a very large reduction in oxides of nitrogen at the expense of higher smoke emissions. Also, the reduction rates of NOx emissions for hot and cooled EGR are similar at load 20%.

• Asian Pacific Journal of Cancer Prevention
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• 제14권9호
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• pp.5495-5501
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• 2013

Background: Alu elements are one of the most common repetitive sequences that now constitute more than 10% of the human genome and potential targets for epigenetic alterations. Correspondingly, methylation of these elements can result in a genome-wide event that may have an impact in cancer. However, studies investigating the genome-wide status of Alu methylation in cancer remain limited. Objectives: Oral squamous cell carcinoma (OSCC) presents with high incidence in South-East Asia and thus the aim of this study was to evaluate the Alu methylation status in OSCCs and explore with the possibility of using this information for diagnostic screening. We evaluated Alu methylation status in a) normal oral mucosa compared to OSCC; b) peripheral blood mononuclear cells (PBMCs) of normal controls comparing to oral cancer patients; c) among oral epithelium of normal controls, smokers and oral cancer patients. Materials and Methods: Alu methylation was detected by combined bisulfite restriction analysis (COBRA) at 2 CpG sites. The amplified products were classified into three patterns; hypermethylation ($^mC^mC$), partial methylation ($^uC^mC+^mC^uC$), and hypomethylation ($^uC^uC$). Results: The results demonstrate that the $%^mC^mC$ value is suitable for differentiating normal and cancer in oral tissues (p=0.0002), but is not significantly observe in PBMCs. In addition, a stepwise decrease in this value was observed in the oral epithelium from normal, light smoker, heavy smoker, low stage and high stage OSCC (p=0.0003). Furthermore, receiver operating characteristic (ROC) curve analyses demonstrated the potential of combined $%^mC$ or $%^mC^mC$ values as markers for oral cancer detection with sensitivity and specificity of 86.7% and 56.7%, respectively. Conclusions: Alu hypomethylation is likely to be associated with multistep oral carcinogenesis, and might be developed as a screening tool for oral cancer detection.

• 지역사회간호학회지
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• 제13권3호
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• pp.481-492
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• 2002

The purpose of this study was to understand and analyze the subjective structure of attitude The method was based on a Q-Methodological approach. The results of this study, there were four categories of smoking middle school students' attitude about smoking. The first type named Self Belief type that this type didn't sensible of their surrounding persons when they were smoking and they also were responsible for strong opinion at their behavior. The second type named Other's Awareness type that they were seen the behaviors they always have to see other person when they were smoked, but if they didn't smoke or have tobaccos they feel heavy and are restless. The third type named Solving of Anxiety type. They first used to smoke when they wanted to solve their anxiety, stress, awkwardness and angry. The fourth type named A Sense of Belonging Group type. This type followed if their friends were smoking they also did it with them. As to grasping of their motivation to smoking of middle school of students with smoking, they felt some intimacy and same quality each other. In consideration of various types of attitude about smoking, it was very necessary important to grasp the meaning because we were known about attitude, belief etc. And then Through getting hold of the meaning, we could understand with their thought and value of Students in middle school. Besides, as a substitute for the students were depending on smoking purposelessly will fix right self-confidence.

• 분석과학
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• 제28권6호
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• pp.385-397
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• 2015

본 연구를 통하여 담배 주류연에 포함되어 있는 HPHCs (Harmful and potentially harmful constituents) 중 7 개 그룹의 분석법을 확립하였다. 이 7 개 그룹에는 방향족 아민, 휘발성 유기화합물, 중금속, 담배특이니트로사민, 벤조[a]피렌, 암모니아, 카르보닐 그룹이 있다. 시험법 검증을 위하여 표준담배인 1R5F와 3R4F를 사용하여 분석법의 특이성, 직선성, 정성한계, 정량한계, 정확도, 정밀도 및 회수율을 확인하였다. 모든 상관계수(r²)는 0.995 이상 이였고 정성한계는 방향족 아민, 휘발성 유기화합물, 중금속, 담배특이 니트로사민, 벤조[a]피렌, 암모니아, 카르보닐 순으로 0.01-0.04 ng/cig, 0.01-0.16 μg/cig, 0.01-1.27 ng/cig, 0.06-0.28 ng/cig, 0.04 ng/cig, 0.08 μg/cig, 0.78-1.77 μg/cig으로 확인되었다. 또한 일간과 일내 상대표준편차는 모두 15% 이하였고, 회수율의 상대표준편차는 15% 이하, 회수율 범위는 79.2-117.5%로 나타났다. 이러한 결과들을 바탕으로 7 개 그룹에 대하여 확립된 시험법은 각각의 해당성분을 분석하기에 적합하다고 판단된다.

• 한국치위생학회지
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• 제19권6호
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• pp.951-961
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• 2019

Objectives: This study aims to evaluate how the amount and duration of smoking effects the bleeding and pain of gingival among adolescents in Korea while also taking into consideration the impact of drinking. Methods: Data were utilized from a web-based survey of youth health behaviors conducted by the Korean Center for Disease Control and Prevention in 2016. The subjects of the study included 65,528 adolescents from middle and high schools. As dependent variables, bleeding and pain of gingival were used. Data were analyzed using the SPSS Version 20.0 program. Results: After adjusting for the general characteristics and oral health behaviors of the subjects, in the long-term, the ≥0.52 PY group (heavy smoker) experienced 1.28 times higher bleeding and pain of gingival than the <0.52 PY group (light smoker) among adolescents who smoke and drink at the same time. Adolescents who smoked without drinking did not show any difference on bleeding and pain of gingival according to the amount of smoking in the short- and long-term. However, the findings reveal that there was a difference on bleeding and pain of gingival according to tooth brushing frequency. Conclusions: In order to promote the periodontal health of adolescents, it is argued that programs and projects should be implemented to prevent, educate, and control simultaneous behaviors of smoking and drinking.

• 한국직업건강간호학회지
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• 제29권1호
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• pp.58-68
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• 2020

Purpose: Workers with chronic health problems find it difficult to maintain their work because of socioeconomic difficulties. The purpose of this study was to evaluate the relationships between physical, ergonomic, and mental health hazards in the workplace and chronic health problems of Korean workers. Methods: A total of 28,807 wage workers participated in the study and were selected using the Fifth Korean Working Conditions Survey (2017). Multiple logistic regression analysis was used to determine the associations between physical, ergonomic, and mental health hazards and chronic health problems. Results: Of the participants, 1,220 (4.23%) had chronic health problems. Even after adjusting the general characteristics, vibration, noise, high temperature, low temperature, dust, chemical and cigarette smoke, fatigue and painful posture, dragging or pushing or moving of heavy objects, repetitive hand or arm movements, working with a computer or smartphone, use of internet or e-mail, and anxiety situations increased the risk of chronic health problems. Conclusion: The study reaffirms that exposure of physical, ergonomic, and mental health hazards in the workplace significantly increases the risk of chronic health problems.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1996년도 International Conference on Agricultural Machinery Engineering Proceedings
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• pp.359-368
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• 1996

The performance and exhaust emissions of a diesel engine using light oil, heated, rice-bran oil , heated rice-bran oil treated with ultrasonic wave, used frying oil, use frying oil treated with ultrasonic wave, used frying oil, used frying oil treated with ultrasonic wave, methyl esters of rice-bran oil and used frying oil have been compared. All the fuels performed satisfactorily in a precombustion chamber-type diesel engine without injection pump recalibration or any engine modification at the range of engine speed from 1600 to 2800 rpm at its full load during a sort period , with the rice-bran oil and rice-bran oil treated with ultrasonic wave requiring somewhat preheating when ambient temperature was below 15$^{\circ}C$. General performance and emission characteristics of light oil and bio-oils were comparable , with the bio-oil based fuels giving very low SO$_2$ and lower smoke readings.

• 한국자동차공학회논문집
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• 제13권5호
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• pp.188-194
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• 2005

The direct injection diesel engine is one of the most efficient thermal engines. For this reason DI diesel engines are widely used for heavy-duty applications. But the world is faced with very serious problems related to the air pollution due to the exhaust emissions of diesel engine. So, that is air pollution related to exhaust gas resulted from explosive combustion should be improved. Exhaust Gas Recirculation(EGR) is a proven method to reduce NOx emissions. In this study, the experiments were performed at various engine loads while the EGR rates were set from $0\%$ to $30\%.$ The emissions trade-off and combustion of diesel engine are investigated. The brake specific fuel consumption rate is very slightly fluctuated with EGR in the range of experimental conditions. The ignition delay increased with increasing EGR rate. The maximum value of premixed combustion for the rate of heat release is increased with increasing EGR rate. NOx emissions are decreased with increasing EGR rate at high load and high speed. It was found that the exhaust emissions with the EGR system resulted in a very large reduction in oxides of nitrogen at the expense of higher smoke emissions.