• Journal of the korean Society of Automotive Engineers
• /
• v.5 no.3
• /
• pp.33-44
• /
• 1983

This paper deals with the experimental study on the behavior of fuel (methanol) in intake manifold by using the basic apparatus which is manufactured the visible straight tube type model. In this study, the new device for liquid film thickness measurement and vaporization rate measurement are introduced to investigate the variation of liquid film thickness along the intake manifold and to observe the effect of vaporization of injected fuel. the results are summarized as follows: 1) The vaporization rate increases in proportion to decreasing of throttle valve angle and growing air fuel ratio. 2) The liquid film thickness along the intake manifold is mostly independent for the throttle valve angle in low air velocity and then affected in high air velocity, but the distribution of the liquid film thickness on circumferential position almost constant in the region of 300mm down stream from carburetor. 3) The mean liquid film thickness is 0.04 - 0.18mm in case of methanol in the region of air velocity Va = 12m/s - 55m/s and decreases with decreasing the throttle valve angle.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2005.11a
• /
• pp.251-255
• /
• 2005

By using liquid film thickness measurement the spray characteristics of swirl injector according to the geometric parameters were investigated in this paper. A specially designed injector having a variable backhole length, swirl chamber length, orifice length was used to measure the liquid film thickness. The spray characteristics of the injector were represented by mass flow rate according to the injection pressure, liquid film thickness in the lower orifice, spray cone angle.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.686-689
• /
• 2003

Many technologies are applied to the measurement of elastohydrodynamic lubrication (EHL) film thickness. In particular, optical in-situ interferometric method has many advantages in making the actual contact behaviors realized with the experimental apparatus. Careful selection of incident lights greatly enhances the fringe resolution up to nanometer scale by using image processing technology. In this work, it is found that dichromatic incident light can provide much finer resolution of EHL film thickness than monochromatic incident light, because it has much more variables of color components to be discriminated among the wavelengths of colors according the variations of EHL film thickness. Some simulated interferometric images are shown how the film thickness is resolutionized in nanometer scale

• Journal of ILASS-Korea
• /
• v.11 no.3
• /
• pp.147-154
• /
• 2006

A specially designed injector using electric conductivity was used to measure the liquid film thickness accurately. The measurement conducted through the precise calibration, accuracy is demonstrated in comparison with the previous theory and the results using other measurement method. The tendency of liquid film thickness for geometric parameters was examined by the precise measurement. The variation of air core and stability are examined through the visualization of the formation of air core in swirl chamber and the variation of liquid film thickness by the time.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2005.11a
• /
• pp.7-8
• /
• 2005

The pseudo MOSFET measurement technique has been a simple and rapid method for characterization of SOI wafers without any device fabrication process. We adopted the pseudo MOSFET technique to examine the surface silicon film thickness dependence of electrical properties of SOI wafer. The measurements showed that turn-on voltage increased and electron mobility decreased as the SOI film thickness was reduced in the SOI film thickness of less than 20 nm region.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.10 no.2
• /
• pp.70-77
• /
• 2006

A specially designed in;ector using electric conductivity was used to measure the liquid film thickness exactly, The measurement conducted through the precise calibration, accuracy is demonstrated in comparison with the previous theory and the results using other measurement method. The variation of internal flow and stability are examined through the variation of liquid film thickness by the time. The tendency of liquid film thickness for geometric parameters was examined by the precise measurement.

• Journal of Mechanical Science and Technology
• /
• v.17 no.11
• /
• pp.1704-1713
• /
• 2003

Point contact film thickness in elastohydrodynamic lubrication (EHL) is analyzed by image processing method for the images from an optical interferometer with monochromatic incident light. Interference between the reflected lights both on half mirror Cr coating of glass disk and on super finished ball makes circular fringes depending on the contact conditions such as sliding velocity, applied load, viscosity-pressure characteristics and viscosity of lubricant under ambient pressure. In this situation the film thickness is regarded as the difference of optical paths between those reflected lights, which make dark and bright fringes with monochromatic incident light. The film thickness is computed by numbering the dark and bright fringe orders and the intensity (gray scale image) in each fringe regime is mapped to the corresponding film thickness. In this work, we developed a measuring technique for EHL film thickness by dividing the image patterns into two typical types under the condition of monochromatic incident light. During the image processing, the captured image is converted into digitally formatted data over the contact area without any loss of the image information of interferogram and it is also interpreted with consistency regardless of the observer's experimental experience. It is expected that the developed image processing method will provide a valuable basis to develop the image processing technique for color fringes, which is generally used for the measurement of relatively thin films in higher resolution.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2003.11a
• /
• pp.368-376
• /
• 2003

In this research, DLC thin films are produced as several hundred nm thickness by PE-CVD method. And then these thin films are estimated tribological characteristics to find out useful possibilities as a protecting film for high-quality function and life extension at MEMs by mechanical properties observation . These are measured thickness and residual stress of DLC coating. Compared after measuring friction coefficient, adhesion force, hardness, cohesive force of coating films. As results all test, we can decide several conclusions. First, friction coefficient decreased, as the load increased. otherwise, friction coefficient increased, as thickness of coating film increased under low load$(1\~50mN)$. Secod, adhesion force increased as thickness of coating films. Third, hardness of coating film is affected by substrate coating film when it is less than thickness of 300nm and it has general hardness of DLC coating film when it is more than thickness of 500nm. Fourth, cohesive force of coating film is complexly affected by hardness, adhesion force, residual stress, etc.

• Journal of the Society of Naval Architects of Korea
• /
• v.49 no.5
• /
• pp.433-439
• /
• 2012

Anticorrosive paint is the most widely used in shipbuilding and the dry film thickness is very important in terms of productivity and assurance of anticorrosive performance. However, it is difficult to achieve the recommended target film thickness because the dry film thickness depends on labor's skill in practice and is affected by a number of parameters, such as spray pressure, paint flow rate, tip size, spray distance, SVR(Solid Volume Ratio), etc. Present paper derives an empirical equation through the correlation analysis of parameters selected by spray experiments of anti corrosive painting in order to predict the coated status. Comparing the calculated results with practical data, we show that the empirical equation can successfully expect DFT(Dry Film Thickness).

• Journal of the Korean Vacuum Society
• /
• v.8 no.3A
• /
• pp.231-237
• /
• 1999

$SrBi_{22.4}Ta_2O_9$ (SBT) thin films of 70~150 nm thickness were prepared on platinized silicon substrates by Liquid Source Misted Chemical Deposition (LSMCD) process, and their microstructure, feroelectric and leakage current characteristics were investigated. By annealing at $800^{\circ}C$ for 1 hour in oxygen ambient, SBT films were fully crystallized to the Bi layered perovskite structure without preferred orientation. The grain size of the LSMCD- derived SBT films was about 100nm, and was not varied with the film thickness. $2P_r$ and $E_c$ of the SBT films increased with decreasing the film thickness, and the 70nm-thick SBT film exhibited $2P_r$ of 17.8 $\mu$C/$\textrm{cm}^2$ and $E_c$ of 74kV/cm at applied voltage of 5V. Within the film thickness range of 70~150nm, the relative dielectric permittivity of the LSMCD-derived SBT film decreased with decreasing the film thickness. Leakage current densities lower than $10^{-7}\textrm{A/cm}^2$ at 5V were observed in the SBT films thicker than 125nm.