• 전기의세계
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• v.40 no.1
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• pp.27-36
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• 1991

교통수단을 효율적으로 잘 활용하는 나라가 세계의 주도권을 행사해 왔다면 지나친 비약이라고 생각하는 사람이 있을지 모르겠으나, 해가 지지않는 나라로 찬란하 문화와 부를 구가했던 영국은 19세기 산업혁명에 의해 세계 최초의 증기 기관차를 개발했고, 20세기초에 들어 세계의 부를 누렸던 미국은 그야말로 자동차의 나라라고 할만큼 많은 자동차를 개발해왔다. 이제 맞이해야 될 21세기의 세계 역시, 어떤 나라가 새로운 교통 system을 개발하느냐 하는것도 관심의 대상이 아닐 수 없다. 앞으로는 지금까지 살아온 세대보다도 더 많은 사람의 교류와 정보의 전달 및 물자의 이동이 필요하기 때문이다. 지금 연구에 박차를 가하고 있는 21세기의 항공분야도 초음속 여객기가 상업화되어 그들의 주장대로 서울에서 Losangeles 간을 4시간대에 비행한든지, 뉴욕과 파리간이 2시간 이내에 비행된다면 세계는 어떻게 변모할 것이며, Europe 대륙에서 영국 Dover 해협을 해저로 통과하는 초고속 열차에 의해 Europe을 한 덩어리로 묶고, Europe 대륙에서 Asia 대륙을 횡단하는 초고속 열차가 실용화된다면 세계는 어떻게 변모 할 것인지를 생각해 볼때, 일일 생활권에 놓인 세계는 사회, 경제, 문화면에서 급속한 변화를 겪게 될 것은 분명하다. 이러한 시대적 변화에 순응하기 위해 우리나라에서도 서울, 부산을 2시간대로 운행 할 수 있는 초고속 열차가 추진되고 있고, 이 서울, 부산간을 축으로 하는 경부 고속전철이 완공된 후 서울에서 광주, 서울에서 강릉을 연결하는 국토종합 개발권의 고속전철이 운행된다면, 지역간 시간적 거리가 단축되고 국토 구조도 많이 변모할 것이며, 행정기관의 지방이전이나 서울 중심의 경제적, 문화적 기능들이 지방으로 많이 분산되어 좁은 국토지만 보다 효율적으로 활용될 것으로 기대된다. 이러한 명제를 안고 추진되는 우리나라의 고속전철사업을 생각하면서 이미 실용화된 선진각국의 고속전철에서 사용되고 있는 중전기기들이 어떻게 응용되고 있는지 살펴보기로 하자.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.3
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• pp.112-118
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• 2019

The development of an underwater rocket propulsion system was described in this paper. Throttle able liquid propellant and hybrid rocket propulsion systems were selected for underwater propulsion. A subscale liquid rocket combustion chamber and it's portable stand were developed and their applicability was examined. 1.5-ton.f and 1.8-ton.f hybrid rockets were developed for underwater applications. The test results indicated that the 18-ton.f hybrid rocket fully complies to the performance and underwater cruise stability requirements; thus, its development was concluded to be successfully complete.

• 월간산업보건
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• s.118
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• pp.27-33
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• 1998

본 분석기법을 소개하고자 하는 목적은 유해인자별 작업환경 측정 및 특수건강진단 시료 분석에 맞는구체적인 분석결과를 제시함으로써 산업보건관련 유관기관에 실질적인 도움을 주고자 함 입니다.

• 월간산업보건
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• s.124
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• pp.46-50
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• 1998

본 분석기법을 소개하고자 하는 목적은 유해인자별 작업환경 측정 및 특수건강진단 시료 분석에 맞는구체적인 분석결과를 제시함으로써 산업보건관련 유관기관에 실질적인 도움을 주고자 함 입니다.

• Journal of the Korean Society for Railway
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• v.12 no.5
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• pp.670-677
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• 2009

This paper is a study of testing on-board signalling equipment in advanced high speed rail at the maximum speed of 400km/h. The on-board signalling equipment in advanced high speed rail provides operating information to the driver when operating at ATC, ATS, and ATP sections, and maintains safety from driver oversight, signalling equipment malfunction, natural disasters and so on. Since the testing train performance of advanced high speed rail at 400km/h must include the function test of on-board signalling equipment, this thesis focuses on the function test of on-board signalling equipment and analyze the necessity of the test at the maximum speed. Finally, it is suggested to change some infrastructure and to use specific test methods to test the train performance at the maximum speed in high speed line ATC section.

• The Korean Journal of Applied Statistics
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• v.29 no.1
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• pp.13-25
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• 2016

High-speed railway (Korea Train Express) has had a deep impact on the regional economy of Korea. Current high-speed rail research is mostly theoretical, there is a lack of quantitative research using a precise algorithm to study the effect of high-speed railway on the regional economy. This paper analyses the influence of high-speed rail on the regional economy, with a focus on the Daegu area. Quantitative analysis using department store indexes and regional medical records is performed to calculate the economic influence of high-speed rail. The result shows that high-speed railway effects the regional economy though regional consumption growth and medical care trends.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.4
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• pp.328-336
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• 2008

The shock tunnel as a hypersonic ground test facility was designed, constructed and its performance test was conducted to reproduce the high speed flow which the hypersonic propulsion system is encountered. The design points were understood and the conceptual design was completed using the quasi one dimensional operation analysis code. After that, the specific performance and compartment design were completed using CFD simulation as the part analysis. The facility was then constructed according to those design results and the performance test was conducted for various operation conditions. In this paper, we suggested the compartment design method using CFD analysis, construction process and various performance test results in detail.

• Journal of Chest Surgery
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• v.34 no.3
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• pp.264-269
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• 2001

흉부 둔상에 의한 기도와 식도의 동시적 파열상은 매우 드물게 발생되고 있다. 그러나 최그들어 고속 교통사고의 증가와 환자에 대한 응급체계의 발전으로 점차 치험 보고례가 증가되고 있다. 저자들은 흉부의 둔상에 의하여 기도와 식도에 종적으로 긴 파열상을 입은 환자 2례의 치험을 보고한다. 1례는 이전 병원에서 시행한 기관식도 재건술이 실패한 상태에서 전원되어와 2차적으로 식도절제 및 기관재건술을 실시하였으나 사망하였고. 다른 1례는 식도절제 및 기도재건술로 합병증이 없이 생존하였다.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.5
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• pp.153-159
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• 2007

The performance of a direct-injection type diesel engine often depends on the strength of air flow in the cylinder, shape of combustion chamber, the number of nozzle holes, etc. This is of course because the process of combustion in the cylinder was affected by the mixture formation process. In the present paper, high speed photography was employed to investigate the effectiveness of holes penetrated from the bottom of cavity wall to piston crown for some more useful utilization of air. The holes would function to improve mixing of fuel and air by the increase of air flow in the cylinder. The results obtained are summarized as follows, (1) Activated first of the combustion by shorten of ignition timing and rapid flame propagation (2) Raised the combustion peak pressure, more close to TDC the formation timing of peak pressure.

• Journal of Advanced Marine Engineering and Technology
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• v.16 no.4
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• pp.60-77
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• 1992

The effects of exhaust gas recirculation(EGR) on the characteristics of exhaust emissions and specific fuel consumption have been investigated using an eight-cylinder, four cycle, direct injection diesel engine operating at several loads and speeds. The experiments in this study are conducted on the fixed fuel injection timing of $38^{\circ}$ BTDC regardless of experimental conditions. In conclusion, it is found that $NO_{x}$ emission is markedly reduced with the drop of burnt gas temperature at high speeds and loads especially as the EGR rate increases, while the soot particulate rises with EGR rate and load at a given engine speed, especially high loads. The reduction of exhaust emissions within the Korea heavy duty diesel engine emission standards can be roughly achieved by the optimal EGR rate without degarding the specific fuel consumption, based on the correlations between exhaust emissions.