Ultra-speed tube train, which runs in vacuum atmosphere to overcome aero-dynamic dragging force, is considered as a high-speed ground transportation system to back up long-distance air travel. To realize the ultra-speed tube train, feasibility study of currently available Maglev technologies especially for propulsion and levitation system is needed. Propulsion by linear synchronous motor(LSM) and levitation by electro-dynamic suspension(EDS) which are utilized in the Japan's MLX system could be one of candidated technologies for ultra-speed tube train. In the LSM-EDS system, the key component is superconducting magnet, and its reliability and performance is very important to guarantee the safe-operation of Maglev. As the initiative of the feasibility study, this paper deals with the basic structure of superconducting magnet and core technologies to design and operate it. And by surveying the current R&D achievement in Korea, the nation's capability to develop advanced superconducting magnet for Maglev is presented.
This study compared the dictionary processing of symbolic words from the lexicographical point of view for each Korean dictionary of South and North Korea.
To summarize the results:
In the North Korean dictionary, ''ponttanmal'' is used as a hyperonym for onomatopoeia and mimetic words. On the other hand, in the South Korean dictionary, there is no representative word to refer to them.
There are more blanks in the symbolic words system in the South Korean dictionary than in the North Korean dictionary.
In the definition of meaning, the South Korean dictionary is divided into three main categories: ''- sounds, - shapes, and feels'', whereas North Korean dictionaries are divided into ''- sounds'' and ''- shapes''.
레벨계는 비침습적으로 매질의 레벨을 측정 할 수 있어 산업계에서 안전과 유지보수와 연관되어 점점 다양한 종류의 레벨계가 사용되고 있는 추세이다. 레벨계는 석탄, 밀가루, 쌀 등의 고체 매질과 물, 석유 등의 액체매질과 같은 여러 종류의 매질에 따라 측정이 가능하며 매질에 따른 오차를 줄이기 위해 도플러 효과를 이용한 계측으로 측정 오차를 보완 할 수 있으나, 신호처리 단계가 더 많아져 연산속도가 더 필요하게 되고 하드웨어 복잡도가 증가하며 고비용 구조가 요구된다. 본 논문에서는 원격 측정 레벨계의 신호처리 연산구조를 개선 하는 방법을 제안하여 연산량을 줄이고 요구되는 FPGA의 리소스 사용량을 줄일 수 있는 방법을 제시하고자 한다.
This research is aimed to seek an alternative and critisize the argument of useless that 2000s appeared in earnest.The policy of standard language with Seoul as the center destroys using dialect and language variety. The standard language was critisized considerably becuase it was likely different f...
Reactive sprays of two propellant combinations(GOx/kerosene and GN₂O/ethanol) were observed and compared with each other as a basic research of visualizing supercritical combustion. A shadowgraph imaging method was used to visualize the reactive sprays, and shadowgraph images were converted to density gradient magnitude images to analyse the structure of reactive sprays. The gas-liquid interface of GOx/kerosene spray showed rougher boundary and steeper density gradient near the injector face than the N₂O/ethanol at similar combustion chamber pressure. Spray core length was calculated from averaged density gradient magnitude images and it was revealed that spray core length of GOx/kerosene was shorter than that of GN₂O/ethanol, although momentum flux ratio of GOx/kerosene propellant combination was lower.
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