• 대한기계학회논문집B
• /
• 제26권6호
• /
• pp.868-874
• /
• 2002

A high-impulse, low-power, digital microthruster has been developed using low-boiling-temperature liquid propellant with high-viscosity fluid plug. The viscous fiction force of the fluid plug increases the blast pressure and the low-boiling-temperature liquid propellant is intended to reduce input power consumption. The three-layer microthruster has been fabricated by surface micromachining as well as bulk micromachining in the size of 7$\times$13$\times$1.5㎣. A digital output impulse bit of 6.4$\times$10$^{-8}$ Nsec has been obtained from the fabricated microthruster using perfluoro normal hexane (FC72) propellant and oil plug, resulting in about ten times increase of the impulse bit using one hundredth electrical input energy compared to the conventional multiple-shot microthruster.

• 한국문헌정보학회지
• /
• 제40권3호
• /
• pp.305-331
• /
• 2006

서지세계의 개념모형인 FRBR은 디지털도서관의 확산으로 그 유용성이 더 증대되고 있다. 이 연구의 목적은 FRBR 모형의 적용 전략을 살펴보기 위한 것이다. 이 연구에서는 해외 적용사례를 대상으로 FRBR 모형의 채택 이유와 FRBR 제1집단 개체의 수용방법을 살펴보았다. 이 연구 결과는 FRBR모형에 대한 연구 및 구현의 활성화를 위해 활용될 수 있을 것이다.

• 대한기계학회논문집
• /
• 제11권1호
• /
• pp.88-96
• /
• 1987

본 논문에서는 Maubach의 방법에 내재된 불합리한점을 보완하고자 Fig.1(b)와 같이 .iota.=0인 곳에서 속도구배를 ㄹ변환하여 마찰계수와 조도함수를 계산하였다. 이 방법에 의해 얻어진 속도분포에서는 .iota.=0인 곳에서 속도구배에 불연적성이 일어나지 않는다.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2002년도 춘계학술대회 논문집
• /
• pp.661-665
• /
• 2002

A lot of investigations have been made in recent years on the equal channel angular pressing (ECAP) which produces ultra-fine grains. The finite element method has been used to investigate this issue. In this paper, pure-Zirconium is considered far ECAP process by three dimensional finite element analysis. The effects of fiction on the deformation behavior have been investigated and compared with two dimensional finite element analysis.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2002년도 춘계학술대회 논문집
• /
• pp.512-515
• /
• 2002

The lubrication characteristics of SAM(self-assembled monolayer) have been investigated according to the change of surface group and surface temperature treatment with FDTS(1H, 1H, 2H, 2H-Perflurodecyltrichlorosilane) SAM and OTS(octadecyltrichlorosilane) SAM in micro scale. From the experimental results, it was found that OTS SAM gets destroyed at $200^{\circ}C$ and stiction and fiction coefficient increased, but FDTS SAM was stable up to $400^{\circ}C$. Also, it was found that the friction coefficient of normal OTS SAM is lower than that of FDTS SAM, but stiction is vice versa. This work shows the importance of surface group of self-assembled monolayer to control the lubrication characteristics and thermal stability.

• 한국정밀공학회지
• /
• 제19권5호
• /
• pp.43-50
• /
• 2002

Friction welding has many merits such as energy efficiency, simple processing, etc butt difficult to obtain good weld at the welded interface and heat affected zone. To date, the continuum mechanics and fracture mechanics are utilized to analyse stresses at the interface and propagation of cracks. In this study. STS304 and SM15C are selected because they can be differentiated distinctively from metallic point of view and crack can be observed easily. It is ovserved during friction welding that STS304, rotary part is hatter than SH15C, fixed part. The last fracture occurs around the center because the surface of fatigue fracture has smooth regions, due to the separation phenomenon in plastic flows layers and striation dimple pattern.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2004년도 춘계학술대회 논문집
• /
• pp.152-155
• /
• 2004

Effects of sliding speed, applied load, counterpart radius and thickness of PMMA (Poly Methyl Methacrylate) coating layers on their dry sliding frictional and wear behavior were investigated. Sliding wear tests were carried out using a pin-on-disk wear tester. The PMMA layer was coated on Si wafer by a sol-gel technique with two different thicknesses, $1.5{\mu}m\;and\;0.8{\mu}m$. AISI 52100 bearing steel balls were used as a counterpart of the PMMA coating during the wear. Normal applied load and sliding speed were varied. Wear mechanisms were investigated by examining worn surfaces by an SEM. Under most of sliding test conditions, the thicker layer with the thickness of $1.5{\mu}m$ showed lower fiction coefficient than the thinner layer. Effects of sliding speed and counterpart's radius on the frictional behavior were varied depending on the thickness of the coating layer.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1999년도 하계학술대회 논문집 B
• /
• pp.880-882
• /
• 1999

Virtual Reality is a set of computer technologies which, when combined, provide an interface to a computer-generated world, and in particular, provide such a convincing interface that the user believes he is actually in a three dimensional computer-generated world. This computer generated world may be a model of a real-world object, such as a house; it might be an world that does not exist in a real sense but is understood by humans, such as a chemical molecule or a representation of a set of data; or it might be in a completely imaginary science fiction world. this paper describes the application of boiler digital control system MMI for power plant using virtual reality

• 대한기계학회논문집A
• /
• 제24권3호
• /
• pp.786-793
• /
• 2000

Nylon, Polyacetal and PTFE were studied to gain a better understanding of their tribological behavior. Wear tests were conducted with reciprocating motion under dry sliding conditions. Friction coefficient and specific wear rate were measured as a function of sliding distance. The worn surfaces were examined with a Scanning Electron Microscope(SEM). Polyacetal showed lowest specific wear rates and PTFE exhibited lowest friction coefficient. The dominant wear mechanism found were adhesion and abrasion.

• International journal of advanced smart convergence
• /
• 제9권1호
• /
• pp.29-36
• /
• 2020

We aim to reinterpret Bong Joon-ho's Snowpiercer through theory of posthumanism. Posthuman is a compound word of 'post' and 'human', which means transcendent-man. However, we would like to extend the meaning of posthuman or cyborgs as not only to "new human figure, or transcendent-man" but as to "human living in a digital age of converged technology". Through the extension of the meaning of posthuman, we would be able to not only find posthuman in Science Fiction movies but also apply it to our real world. Also, through the extended meaning, we will reinterpret all the elements from the film as cyberspace and as posthuman or cyborgs. Moreover, through examination of these "cyborg figures" in Bong Joon-ho's Snowpiercer (2013), we argue that the film is criticizing posthumanism in the reality that these days, people are losing the humanity due to the combination with the machine. It seems that he claims of the collapse of the current system, suggesting new human generation as the solution.