• 한국초전도ㆍ저온공학회논문지
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• 제16권4호
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• pp.53-56
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• 2014

A numerical method of magnetic field calculation for the air-core solenoid is presented in this paper. In application of the Biot-Savart law, the magnetic field induced from the source current can be obtained by a double integration ormula. The numerical method named composite Simpson's rule for the integration is applied to the program and the adaptive quadrature method is used to adjust the step size in the calculation according to the precision we need. When the target point is in the solenoid and the intergrand's denominator may be zeroin the process of calculation, the method sill can provide an appropriate result. We have developed a program which calculates the magnetic field with at least 1ppm precision and named it as rzBI() to implement this method. The method has been used in the design of an MRI magnet, and the result show it is very flexible and convenient.

• 설비공학논문집
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• 제11권6호
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• pp.799-807
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• 1999

Exergy analysis is widely used in energy system analysis for more efficient energy use. Pinch technology has focused on chemical plants, such as pure heat exchanger networks. In this study, the objective is to seek more effective means with integrating above two methods. In order to demonstrate effective result and to prove possibility for pinch analysis, the steam turbine is adopted to make heat recovery in the heat exchanger network. Three cases are introduced using the integration of exergy and pinch analysis. The standard steam turbine utility is the base case, and adding the heat pump to this system is the second case. The third case is the system with the heat pump and minimum utilities. The results show that the output power of steam turbine in the case(2) and case(3) are increased up to 42% and 46%, respectively, compared with that of base case.

• 항공우주정책ㆍ법학회지
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• 제4권
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• pp.37-49
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• 1992

In the changing glabal order, international aviation order is also challenged. Regionalism including EC integration press us to review and renew traditional international aviation legal order. Under such a significant circumstances, this paper examines the legal concept of freedoms of air and air cobotage and problems of their expanded applications. The papar particularly analyzes various concepts of cabotage and arguments in the interpretations of article 7 (cabotoge) of Chicago Convention and presents alternatives of future direction to accommodate problems which world aviation community faces today.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 1998년도 유체기계 연구개발 발표회 논문집
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• pp.209-214
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• 1998

A thermodynamic simulation method is developed for the process design and the performance evaluation of the gas turbine in IGCC power plant. The present study adopts four clean coal gases derived from four different coal gasification and gas clean-up processes as IGCC gas turbine fuel, and considers the integration design condition of the gas turbine with ASU(Air Separation Unit). In addition, the present simulation method includes compressor performance map and expander choking models for considering the off-design effects due to coal gas firing and ASU integration. The present prediction results show that the efficiency and the net power of the IGCC gas turbines are seperior to those of the natural gas fired one but they are decreased with the air extraction from gas turbine to ASU. The operation point of the IGCC gas turbine compressor is shifted to the higher pressure ratio condition far from the design point by reducing the air extraction ratio. The exhaust gas of the IGCC gas turbine has more abundant wast heat for the heat recovery steam generator than that of the natural gas fired gas turbine.

• 한국군사과학기술학회지
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• 제13권6호
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• pp.1019-1025
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• 2010

This paper describes on methods in test and evaluation of the guided rocket munitions of the domestic new generation multiple launcher rocket system. We modified and refer to the present model of air-to-air missile(AAM) and surface-to-air missile(SAM). Also we suggested a method of surface-to-surface missile(SSM) based on the characteristics of the guided rocket in test and evaluation(T&E). According to this study, the suggested activity of T&E should be observed methods compatible with each item on the established model. Therefore, we expect that the proposed research material will be a good guide to the study of a surface-to-surface missile(SSM) installed GPS/INS integration navigation guidance & control systems in the future.

• 한국군사과학기술학회지
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• 제20권6호
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• pp.788-793
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• 2017

This military aircraft requires the compatibility evaluation of armed installations in accordance with guidelines and standards. In order to ensure the influence of gas-air mixtures caused by gunfire of the supersonic aircraft, CFD analysis of internal and external flows was performed and the results carried out and discussed. The low velocity vortex was formed due to the shape of the Gun Port, after firing the gas-air mixture was evacuated to the outside flow, where it moved to the front of the aircraft and soon merged with the aircraft flow field.

• Journal of Positioning, Navigation, and Timing
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• 제11권1호
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• pp.51-58
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• 2022

Korea Augmentation Satellite System (KASS) is a Satellite Based Augmentation System (SBAS) system under development in South Korea and aims to provide air navigation services after 2023. In order to provide reliable service, detailed design for the operation of this system is required. This paper proposes a detailed operation-based designs based on mission, architecture, operation definition of the system. For the stable operation of the system, an operation organization was designed and operation activities were classified in consideration of the architecture and function of the system. Detailed operation procedures were designed according to this classification and operation procedures related to the command and configuration of subsystem were verified on the Integration, Verification and Qualification (IVQ) platform for integrated testing and verification. The proposed operation concepts and procedures will be continuously confirmed and verified during verification, qualification and service preparation, and will be updated event after official KASS service.

• 한국항공운항학회지
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• 제22권1호
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• pp.108-113
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• 2014

Recently increase in the number of aircraft caused the air traffic congestion and flight delays. If timely action to reform the air traffic system is not taken, these may result in added economic impact. As a result, the air traffic management should be changed in an innovative manner to modernize the existing air traffic control environment. This paper reviews the trends of airspace reforms such as integration of terminal control areas and flexible use of airspace introduced by foreign countries and compares their merits and demerits in order to provide a judgement to adopt the concept in domestic airspace in the future.

• Clinical and Experimental Pediatrics
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• 제55권6호
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• pp.185-192
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• 2012

The prevalence of allergic diseases has increased worldwide, a phenomenon that can be largely attributed to environmental effects. Among environmental factors, air pollution due to traffic is thought to be a major threat to childhood health. Residing near busy roadways is associated with increased asthma hospitalization, decreased lung function, and increased prevalence and severity of wheezing and allergic rhinitis. Recently, prospective cohort studies using more accurate measurements of individual exposure to air pollution have been conducted and have provided definitive evidence of the impact of air pollution on allergic diseases. Particulate matter and ground-level ozone are the most frequent air pollutants that cause harmful effects, and the mechanisms underlying these effects may be related to oxidative stress. The reactive oxidative species produced in response to air pollutants can overwhelm the redox system and damage the cell wall, lipids, proteins, and DNA, leading to airway inflammation and hyper-reactivity. Pollutants may also cause harmful effects via epigenetic mechanisms, which control the expression of genes without changing the DNA sequence itself. These mechanisms are likely to be a target for the prevention of allergies. Further studies are necessary to identify children at risk and understand how these mechanisms regulate gene-environment interactions. This review provides an update of the current understanding on the impact of air pollution on allergic diseases in children and facilitates the integration of issues regarding air pollution and allergies into pediatric practices, with the goal of improving pediatric health.

• 한국항행학회논문지
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• 제7권2호
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• pp.180-190
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• 2003

실수축 상의 적분 방법에 의한 정확한 closed-form 그린함수를 이용하여 코플래너 도파로의 불연속에 대한 공간영역 full-wave 해석을 하였다. MPIE(Mixed Potential Integral Equation)를 풀기 위한 수치계산 방법으로는 삼각형 요소를 이용한 갤러킨 방법을 사용하였다. 경계면에서 삼각형 요소상의 기저함수로는 선형함수를 사용하였으며, 관측점과 전원점이 일치하는 특이점 근방의 적분 계산을 위해 면적분을 선적분 형태로 바꾸어 피적분 함수의 특이점이 사라지도록 하는 해석적인 방법을 사용하였다. 실수축 적분방법에 의한 그린함수를 이용함으로써 불연속에 대한 정확한 특성을 구하였다.