• Journal of the Korean Institute of Gas
• /
• v.8 no.4 s.25
• /
• pp.30-35
• /
• 2004

In this paper, the metal seal for a pressure vessel has been analyzed using the Daguchi method. This method may efficiently optimize the design parameters for a cantilever sealing device of a pressure vessel in terms of dimensions and angles. The computed results indicate that the optimized design parameters can only be drawn by sixteen experimental numbers of iterations when the Daguchi design technique has been employed. This means that the Daguchi design method is very useful for the optimization design of the curved design of the structure. Based on the computed results by the Daguchi design technique, the dimension and angle of the metal seal structure are given as $d_1=50mm,\;d_2=60mm,\;a_1=20^{\circ},\;a_2=8^{\circ},\;a_3=5^{\circ}$.

• Tribology and Lubricants
• /
• v.26 no.1
• /
• pp.61-67
• /
• 2010

The purpose of this paper is to study and analyze the failure examples on tribological characteristics of an automotive steering system. In this failure study, the grease leakage may stick leaked grease, dust, and wear particles between pinion and rack gears in mechanical steering system. In the case of seal failures such as a rod seal, o-ring and oil seals, the gear box and oil pump do not operate properly due to lack of oils. This means that oil pump does not supply a working fluid and produce a normal oil pressure of the steering system. This leads to leak a working fluid from the seals and produce a wear between pinion and rack gears. Especially, the leaked oil is usually mixed with internal wear particles and foreign dust/fine sands. Thus no leakage of working oils is very important design concepts, which is strongly related to the sealing components and smoothly operating of the mechanical friction parts of power steering system.

• ICROS
• /
• v.20 no.3
• /
• pp.22-26
• /
• 2014

본 기술 동향에서는 햅틱 기술과 관련된 최근의 동향에 대해서 살펴보기로 한다. 특히 진동 촉각을 기반으로 한 모바일 기기용 햅틱스는 관련 연구들이 활발하게 진행 중이며 이 중에 몇 가지 연구들과 활용되는 액추에이터 등에 대한 연구들을 바탕으로 앞으로의 촉각 기반 생태계를 예측해 보고, 아울러 의료 휴대폰, 컴퓨터, 재활 분야등에서 필요로 하고 또 활용 가치가 있는 햅틱 기술들에 대해서 고찰해 보기로 한다. 최근에 각광받는 웨어러블 기기등도 내부에 다양한 센서와 액추에이터를 내장하려는 움직임이 있고, 휴대폰 등에서 진동 액추에이터를 활용하여 소리를 대체하듯 촉각 기술이 터치 스크린 기반 시장을 한 단계 발전시켜 차세대 입력 장치로 발전할 수 있는 가능성을 가늠해 볼 수 있을 것이다. 지속적인 연구를 통해 관련 분야에서 필요한 촉각 기술을 개발한다면 햅틱 연구자들이 그토록 염원하는 촉각 기반 시장의 확대 성장도 그리 오랜 시일이 걸리지 않을 것으로 기대한다.

• Journal of Advanced Marine Engineering and Technology
• /
• v.15 no.5
• /
• pp.47-54
• /
• 1991

The lip seals widely used nowadays in stern tube sealing system of ships have radial sealing contact with shafts or liners, on the other hand the face seals of stern tube sealing system have axial sealing contact with seat. Because of axial sealing contact, the face seals have a large number of merits such as durability of life, simplicity of structure, easy fitting and replacement, etc. In this paper, for the purpose of development of face seals, the fundamental properties of axial sealing contact were analyzed and a trial face seal was designed and manufactured using N.B.R. rubber and Thordon which is widely used for bearing materials. The seal proper of trial face seal was made from N.B.R. rubber and the face insert was made from Thordon, thermosetting resins which are three dimensional, cross linked condensation polylmers. The performance test of trial face seal was carried out on the test bench which was specially designed and manufactured. The results were satisfactory enough to be used in practical stern tube sealing system.

• Proceedings of the Korean Information Science Society Conference
• /
• 2006.10c
• /
• pp.12-17
• /
• 2006

플래시 메모리는 기술 발전에 따른 빠른 용량 증가와 모바일 환경에 우수한 특성으로 인해 가까운 시일내에 하드 디스크를 대체할 대용량 저장 장치로서 주목 받고 있다. 이러한 흐름에 따라 플래시 메모리 사용이 증가하고 플래시 메모리에 저장하는 데이터의 양이 점차 많아지면서 플래시 메모리 상의 효율적인 인덱스 구조에 대한 필요성도 함께 증가하고 있다. 하지만 기존의 대표적인 인덱스 중 하나인 B-트리 인덱스를 플래시 메모리에 적용하기 위해서는 하드 디스크와 플래시 메모리 간의 다른 특성들 때문에 플래시 메모리에 맞게 인덱스 구조를 수정하는 작업이 필요하다. 본 연구에서는 이를 해결하기 위한 기존의 연구에 대해 소개하고 기존 연구의 한계점과 이를 개선한 인덱스 구조를 제안한다.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.35 no.1
• /
• pp.50-53
• /
• 1999

In this paper, the mechanical movement of lip seal-ring which plays the most important function in stern-tube sealing system and the possibility of leakage caused by pressure fluctuation are studied by theory and experiment. By the finite element method for axial symmetry object which receives the torsional bending load, the displacement and stress analysis of the seal-rings are executed for products of several representative manufacturers of seal-rings, and also the possibility of crack occurance are checked by theoretical analysis. A sample seal-ring id designed and manufactured using the program of displacement and stress analysis developed in this study and made an experimental apparatus to test the sampling seal-ring. The sampling seal-ring functioned excellently, but it had its durability and this problem may be solved by using the Viton instead of NBR.

• 전기의세계
• /
• v.9
• /
• pp.46-50
• /
• 1962

전력계통의 운영에 있어서 예컨데 손실전력의 감소라든가 안정한 운전의 검토 또는 전력계통의 계획시에 있어서 경제적인 송전선 및 변전소의 건설지점개정, 송전망구성방법, 고장시의 대책등을 결정하는데 있어서는 이에 관한 각종 계산을 할 필요가 생기게 된다. 그러나 복잡한 전력계통에 있어서 이들 문제를 사람이 직접 계산 해결한다는 것은 용이한 일이 아니며 필요로하는 많은 시일과 노력 및 이에 대한 그 결과의 부적확등으로 모든 문제를 다 계산하여 해결한다는 것은 바랄 수 없었다. 이와같은 전력계통의 계산을 단시간에 또한 정확하게 가능하도록 한 것이 교류계산반이다. 교류계산반은 다수의 막정발전기, 가변저항, 가변 Inductance, 가변 capacitance, 변압기등의 전위를 비치하고 이들 전위를 연결하여 실제전력계통과 같은 모위회로를 만들고 각부의 전압, 전류, 전력, 위상각등의 제량을 측정함으로써 실계통의 제특성을 신속히 파악 분석하게 한 것으로서 계산기의 분류중에서는 Analogue형의 직접형에 속하며 특히 이 교류계산반은 직접상이형인 계산장치이다.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
• /
• 2005.09a
• /
• pp.55-58
• /
• 2005

플렉서블 디스플레이를 이용한 대 화면의 디스플레이 제작을 위해, 굽혀짐이 가능한 디스플레이용 재료, 장비, 공정 기술 개발이 활발하게 추진 중이지만, 상용화로 제품이 출시되기에는 상당한 시일이 소요될 것으로 예상되므로, 대 화면을 요구하는 시장 환경에 부응하여 접이식 디스플레이 장치가 대안이 될 수 있다. 따라서 접이식 디스플레이 패널 제작 시에 패널을 구동하기 위해, 이음매를 최소로 하는 접이식 구동 임베디드 모듈의 개발이 요구되고 있으며, 이러한 요구에 발맞추어 새로운 시스템 개발 시마다 변형된 표준에 부응한 경쟁력 있는 핵심 칩 개발용 임베디드 모듈이 제안되었고, 임베디드 모듈은 추후 칩 기능 최적화의 시스템 온칩화(System On Chip)를 통하여 시스템의 프로세서와 주변 디바이스에 접목되어 사용되는 플랫폼 등으로 연구될 수 있다.

• Journal of Advanced Marine Engineering and Technology
• /
• v.15 no.4
• /
• pp.29-45
• /
• 1991

Lip type stern tube sealing systems have used in almost all the middle or large ships which are being constructed in these days. It seems that the pressure fluctuation of the seal ring interspace, the cross-section profile and the materials quality of the seal rings have great effects on the sealing fuction of this sealing system. In this paper, the mechanical movement of lip seal ring which plays the most important role in stern tube sealing system and the possibility of leakage caused by pressure fluctuation are studied by theory and experiment. Using the finite element method for the axi-symetric object which receives the torsional load, the displacement and stress analysis of the seal rings, and also the possibility of crack occurance is checked by theoretical analysis. If the force which seal ring lip periphery receives is too small, there will be the possibility of leakage caused by the pressure fluctuation of the seal ring interspace, and if this force is too large, the frictional force between the seal ring and the liner will become problematical. The possibility of leakage caused by hardening of seal ring materials and creep phenomena of tested seal rings are also examined. The trial seal rings were designed and manufactured using the program of displacement and stress analysis developed in this study and the experimental apparatus to test the trial seal rings was also designed and manufactured. This trial seal rings were fitted in the experimental apparatus which was made in the same form as an actual stern tube. The one side of this apparatus was filled with sea water and the other side of it was filled with the lubricating oil. The leakage of oil and sea water was checked and the temperature was measured, rotating the propeller shaft at the constant velocity by D.C. motor. It was proved that the trial seal rings made in Viton rubber functioned excellenty but the trial seal rings made in N.B.R. rubber had problem in its durability.

• Journal of Advanced Marine Engineering and Technology
• /
• v.37 no.2
• /
• pp.236-241
• /
• 2013

It requires long time and high cost for an apprentice engineer to reach the level of getting various experiences of engine space machinery and preparing for emergency situations. Therefore reducing the time and cost, several types of simulator that give the very similar surroundings to the ship engine room, relevant to STCW-95 are used for systematic education and training to get many experiences and good judgement in emergency. Since most simulators that are operated in Korea were imported from foreign countries, it is difficult to directly implant the amendments of STCW Convention and reflect International Maritime Organization (IMO) model courses. This study describe a development of marine auxiliary boiler simulator that makes the apprentice engineer easier to understand the relationship between equipments in steam system such as auxiliary boiler, exhaust gas boiler, and steam turbine.