• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.11
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• pp.775-784
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• 2017

The purpose of this study was to analyse the basic data of the engine tuning inspection by confirming the working possibility of effective engine tuning and identifying the characteristics of tuned engine that are no problem with the safety operation and environment in a driving gasoline car. The effects of tuned engine on the characteristics of air/fuel ratio and performance at a wide range of engine speeds were experimentally investigated by the actual driving car with a four-cycle, four-cylinder DOHC, turbo-intercooler, water-cooled gasoline engine operating under four types of non-tuning, and tuning 2-1, 2-2 and 2-3. The tuned parts of engine in a driving gasoline car include the intake manifold, intake pipe, air filter, exhaust manifold, exhaust pipe and silencer. In this experiment, the air-fuel ratio and torque of both non-tuned and tuned engines that one person took on board in the car with a five-speed automatic transmission were measured by the chassis dynamometer(Dynojet 224xLC). It was found that the maximum torque of tuned engine in a driving gasoline car was increased by 103.68% on average, while the maximum output was increased by 119.68% on average in comparison to the non-tuned engine.

• Clinical and Experimental Pediatrics
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• v.53 no.2
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• pp.190-194
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• 2010

Purpose : To investigate the nature of deviant voice physiology in preoperative children with congenital heart disease. Methods : Ninety-four children with congenital heart disease were enrolled. Their cries and related acoustic variables (fundamental frequency, duration, noise to harmonic ratio, jitter and shimmer) were analyzed using a multi-dimensional voice program. Results : The average fundamental frequency showed a significant decrease in patent ductus arteriosus, ventricular septal defect, and tetralogy of Fallot, except in atrial septal defect and pulmonary stenosis. The length of the analyzed sample (duration) did not show a significant difference when compared with the control group. There was a significant increase in jitter percent in ventricular septal defect, patent ductus arteriosus, and atrial septal defect. There was an increase in shimmer in ventricular septal defect, patent ductus arteriosus, and atrial septal defect. The noise-to-harmonic ratio increased in ventricular septal defect, patent ductus arteriosus, and atrial septal defect but there was no significant difference in pulmonary stenosis and tetralogy of Fallot. While analyzing acoustic variables, the voice change was significantly higher, especially in patent ductus arteriosus followed by ventricular septal defect and atrial septal defect. Most of these acoustic variables were deviant in left-to-right shunt lesions in congenital heart disease, especially in patent ductus artriosus. Conclusion : The results of the voice change analysis of preoperative children with congenital heart disease revealed that the acoustic variables differed by each congenital heart disease. Moreover, the acoustic variables were prominently deviant in congenital heart disease with left-to-right shunts.

• Journal of the korean Society of Automotive Engineers
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• v.18 no.5
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• pp.53-68
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• 1996

마그네슘이 자동차 경량화에 관심이 되는 이유는 근본적으로 CAFE 규제와 같이 경량화를 통한 화석연료의 소모를 크게 억제해야 한다는 사회적인 규제이나, 지난 10여년간의 기술발전으로 내식성이 나쁘다거나 취급이 위험한 금속이라는 인식이 크게 개선된 데에도 있다. 다른 경량금속에 대한 Mg 지금 가격의 비교조건이 호전되었고 향후 원소 재공급의 다변화가 추진되고 있는 것도 환경을 변화시킨 중요한 요인이다. 그간 중요한 경량화 대체 재료로 연구투자가 많았던 유기고분자 재료 및 FRP 등과 같은 복합재료는 폐기부품의 재활용이 어려움 때문에 호나경친화적인 단점이 부각되어, 이 소재의 증가가 주춤해 있다. 마그네슘의 경우에는 재활용이 가능하고, 진동흡수효과가 매우 커서 소음발생을 크게 줄일 뿐만 아니라, 주행 및 내구성시험에서 치수안정성이 좋고 많은 종류의 전자기기 사용에 의한 전자파 차폐효과도 큰 장점을 가지고 있다. 본 고에서는 Mg 다이캐스팅으로 자동차부품의 경량화 현황과 선진국에서 보는 전망을 미국을 중심으로 정리하고, 이와 관련한 Mg 다이캐스팅으로 자동차부품의 경량화 현황과 선진국에서 보는 전망을 미국을 중심으로 정리하고, 이와 관련한 Mg 기술적인 이슈와 시장전망도 서술하였다. 그리고 현재 우리나라의 연구계와 부품업계에서 추진하고 있는 연구개발 동향을 자동차 업계에 소개하는 의미도 있다. 이처럼 우리나라의 현황을 정리해 보는 것은 국내 자동차 산업이 국제적인 경쟁을 하고 있고 Mg기술과 원료확보에서 일본의 견제를 받고 있는 우리의 현실에서도 필요한 작업으로 생각된다.값들로 구성되는 형상을 내구 성능, 성형성등을 고려하여 최종 형상으로 결정한다. 내구성능의 예측은 금속부품의 내구수명 예측에 널리 이용되고 있는 방법이 방진 고무부품의 경우에도 적용 가능한지를 검토하고, 방진 고무부품에도 일반적으로 적용될수 있는 내구수명 예측방안의 개발 가능성을 타진해 보았다. 본 연구의 목표는 시제품을 제작하기 이전에 설계된 부품에 대한 스프링 상수 및 내구특성을 체계적으로 규명하여 제품 시험의 횟수를 줄이고, 보다 정밀한 제품을 제작할 수 있도록 하기 위한 것이다.세포수는 초기 배반포기배에서 팽윤 배반포기배로 진행됨에 따라 두배에서 세배 정도 증가되었음을 알 수 있었다. 또한, differential labelling과 bisbenzimide기법에서 얻어진 각각의 총세포수를 비교하였을 때 총세포수는 발달의 진행 정도에 따라 증가되며 그와 동시에 동일한 군 간의 세포수도 거의 유사함을 알 수 있었다. 따라서, ICM과 TE를 differential labelling하는 기법은 수정란의 quality를 평가하는데 매우 유용한 기법으로서 착상전 embryo 발달을 연구하는데 효과적으로 이용될 수 있다는 것을 시사한다. 고도의 유의차를 나타낸 반면 비수구, 초생수로구 및 Bromegrass 목초구 간에는 아무런 유의차가 인정되지 않았다. 7. 농지보전 처리구인 배수구와 초생수로구는 비처리구에 비해 낮은 침두 유출량과 낮은 토양유실량을 나타내었다.구보다 14% 절감되는 것으로 나타났다.작용하는 것으로 사료된다.된다.정량 분석한 결과이다. 시편의 조성은 33.6 at%

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.39-39
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• 2018

최근 플라즈마 의학이 발달하면서 제트, 펜, 니들, 토치 등의 다양한 형태의 플라즈마 발생기가 개발되었으며 내부의 가스라인으로 가스의 종류, 유속, 조성 등을 조절하여 생물학적 효과를 극대화 할 수 있고 안정적으로 플라즈마 방전상태를 유지할 수 있으나 처리 면적이 좁아 실제 생물학적 시스템 (세포, 조직, 그리고 박테리아) 적용에 있어 한계점이 존재한다. 이러한 한계점을 극복하기 위해서 유전체격벽방전 (Dielectric barrier discharge, DBD) 방식을 이용한 플렉서블 활성종 발생기를 제작하고 생물학적 시스템에 적용하기 위한 방전 특성 평가를 진행하였으며, 간단한 in vitro 모델인 한천 젤을 이용하여 플라즈마 처리에 따른 전달물질의 침투거리를 확인하였다. 플라즈마 방전 시 생성되는 수산화기 [OH], 과산화수소 [$H_2O_2$], 초산소음이온 [$O_2{^-}$], 오존 [$O_3$], 그리고 산화질소 [$NO_x$]와 같은 산소 및 질소 활성종 (Reactive oxygen and nitrogen species, RONS)은 세포벽 또는 세포막의 주요 구성성분인 다당류와 인지질의 과산화 반응을 통해 구조를 변화시키고 생물학적 시스템의 표면의 pH를 낮춘다. 이러한 RONS의 작용은 살균, 소독 뿐만 아니라 약물의 침투를 돕는다. 일반적으로 한천 겔은 농도에 따라 생체 내 뇌 조직과 물리적 특성이 유사하고, 미생물학 기질, 방사선학 연구를 위한 조직모델로 사용되기 때문에 본 연구에서는 3%와 5% 농도의 한천 젤을 사용하여 침투거리를 확인하였다. 한천 젤은 $2.5{\times}2.5{\times}2.5cm^3$의 크기로 준비되었고 대조군으로 염료가 포함된 에멀젼을 0.01 g 도포하고, 실온에서 30분간 보존 후 단면을 잘라 현미경으로 침투거리를 확인하였으며, 실험군으로 플라즈마 전처리 후 에멀젼을 도포한 시표와 에멀젼 도포 후 플라즈마 처리한 시료에 대해 에멀젼 침투거리의 변화를 확인하였다. 본 연구의 플렉서블 활성종 발생기는 인체에 부착하여 사용되기 때문에 화상, 홍반을 유발을 방지하기위해 $40^{\circ}C$의 온도에서 실험을 진행하였고 이때에 플라즈마 방전조건은 $0.065W/cm^2$ 수준의 전력을 소모하는 1.7 kV의 전압, 16 kHz의 주파수로 10분간 처리하였다. 그 결과 3%의 한천 젤의 경우 침투거리 0.779 mm에서 0.826 mm, 0.942 mm까지 침투거리가 증가하였고 5%의 한천 젤의 경우 0.859 mm, 0.949 mm로 증가하였다. 이러한 침투거리 증가는 젤 표면의 다당류를 구성하고 있는 단량체가 플라즈마 처리시 화확적 구조가 끊어져 결론적으로 약물 침투가 증가된 것으로 판단된다.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.4
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• pp.558-563
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• 2000

The lasers have been used in dentistry for more than 30 years and the application of lasers for drilling dental hard tissue has been investigated since the early developement of lasers. Recently, the Er:YAG laser was invented for hard tissue ablation. The Er:YAG laser, having a wavelength of 2.94um, is highly absorbed in both water and hydroxiapatite, leading to a very effective material for hard tissue removal by bursting off the solid tissue component that is, enamel and dentin are removed by the Er :YAG laser by water vaporization and microexplosion, without any melting of inorganic tissues. Therefore, the Er:YAG laser produced round craters with well defined margins and the surrounding tissues had no cracks and no charring. When used for cavity preparation, pulpal damage should not occur if hear buildup is minimized by careful selection of exposure parameters and by use of a water spray. The present study demonstrated that the Er:YAG laser cut the tooth substance adequately for composite resin restoration, without having undesirable side effects such as harmful effects on the pulp, discoloration or cracking etc. Also, the child patients were well cooperative during laser treatment mainly because of little noise, lesser vibration and minimal pain compared to conventional means of cavity preparation.

• Journal of the Korean Society for Nondestructive Testing
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• v.27 no.4
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• pp.305-312
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• 2007

Among many types of light rail transits (LRT), the rubber-tired automated guide-way transit (AGT) is prevalent in many countries due to its advantages such as good acceleration/deceleration performance, high climb capacity, and reduction of noise and vibration. However, AGT is generally powered by high-voltage electric power feeding system and it may cause electromagnetic interference (EMI) to measurement sensors. The fiber optic sensor system is free from EMI and has been successfully applied in many applications of civil engineering. Especially, fiber Bragg grating (FBG) sensors are the most widely used because of their excellent multiplexing capabilities. This paper investigates a prestressed concrete girder bridge in the Korean AGT test track using FBG based sensors to monitor the dynamic response at various vehicle speeds. The serviceability requirements provided in the specification are also compared against the measured results. The results show that the measured data from FBG based sensors are free from EMI though electric sensors are not, especially in the case of electric strain gauge. It is expected that the FBG sensing system can be effectively applied to the LRT railway bridges that suffered from EMI.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.35 no.1
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• pp.73-96
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• 2024

This study aimed to establish a systematic and comprehensive operational plan for the library to be constructed in the Gwacheon Knowledge Information Town. To achieve this, a survey on the demand for library operations was conducted among actual users of the Gwacheon City Public Library, and plans for the library collection development, user services, and methods to revitalize use were formulated based on the survey results. The findings are as follows. First, the library's construction/space analysis results suggest the need for a multifunctional cultural space accessible to everyone, serving as both a relaxation area and venue for a free information exchange and communication, allowing for a certain level of noise to facilitate an open atmosphere for users. Second, the analysis of the preferred types and forms of library materials revealed that printed materials ranked first, followed by web resources in the second place, and e-books/e-journals in the third. Additionally, there was a high preference for subjects such as literature and history. Third, a high preference was observed for cultural and arts programs, indicating the need for the future Gwacheon Knowledge Information Town Library to strengthen and implement programs focusing on cultural and artistic themes.

• Journal of Korean Tunnelling and Underground Space Association
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• v.26 no.5
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• pp.449-461
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• 2024

The use of tunnel boring machine (TBM), a mechanized excavation method with low noise and vibration and high safety compared to NATM method, has increased globally. In particular, slurry shield TBMs are used in subsea and submarine sections because they have an advantage in high pressure compared to EPB (earth pressure balanced) methods. As such, the used water of slurry shield TBMs is discharged through wastewater treatment facilities. In the case of large-scale TBMs, the amount of water used is enormous, so it should be recycled to reduce costs and protect the environment. Various types of additives are used to improve the performance of the slurry treatment plant (STP) and filter press. Among them, coagulants improve the productivity of the filter press by neutralizing the charges on particles. In this study, lab tests were conducted to evaluate the reusability of the used water through the filter press after flocculants were added.

• Journal of Environmental Policy
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• v.8 no.4
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• pp.125-147
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• 2009

The Basic Environmental Policy Act (BEPA) (Law No. 4257 effective 1. August 1990) sets forth the basic policies and administrative framework for environmental preservation, leaving more detailed regulations, and emission controls to separate laws targeting air, water, and solid waste, etc. The BEPA Article 31 adopts an unprecedented strict liability standard for damages as an absolute liability. The BEPA Article 31 provides for liability as follows. If a company is alleged to have caused damage through pollution of the environment, it will be liable for damages unless it can show that the pollution did not cause damages, or that it did not actually cause pollution. If the company did cause pollution, and if the pollution is the cause for the damages in question, the company will be liable irrespective of whether it was negligent or otherwise at fault. If there are two or more companies involved in the pollution, but it is unclear which company caused the damages, all of the companies will be jointly and severally liable for the damages. In this paper, the author attempts to uncover the problems of BEPA Article 31 and then seeks desirable amendments by comparing it to the German Environmental Liability Act. First, it will be necessary to provide definitions of 'companies etc.'. Second, it will be necessary to enumerate the kinds of company facilities. Third, it will be necessary to provide exclusionary clauses on material damages. Fourth, it will be necessary to show 'presumption of cause and effect'. Fifth, it will be necessary to provide a clause on 'right to information'. Sixth, it will be necessary to provide a clause for force majeure. Seventh, it will be necessary to take measures to secure abundant liability for damages which can be caused by the owner of the facility, the potential polluter. Finally, it is appropriate that Korea now legislate an Environmental Liability Act akin to the German Environmental Liability Act.