• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.22 no.1
• /
• pp.15-21
• /
• 2013

In this paper, a high-speed imaging and an image processing technique have been applied to detect the position of a meniscus as a function of time in the micro capillary flows. Two fluids with low and high viscosities, ethylene glycol and glycerin, were dropped into the entrance well of a circular capillary tube. The filling times of the meniscus in both cases of ethylene glycol and glycerin were compared with the theoretical models - Washburn model and its modified model based on Newman's dynamic contact angle equation. To evaluate the model coefficients of Newman's dynamic contact angle, time-varying contact angles under the capillary flows were measured using an image processing technique. By considering the dynamic contact angle, the estimated filling time from the modified Washburn model agrees well with the experimental data. Especially, for the lower-viscosity fluid, the consideration of dynamic contact angle is more significant than for the higher-viscosity fluid.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.17 no.2
• /
• pp.121-126
• /
• 2004

In this paper, the effects of the ozone oxidation of the landing polycrystalline silicon on the cell contact resistance of the DRAM device were studied. For this study, the ozone oxidation of the landing polycrystalline silicon layer was performed under various conditions, which was followed by the normal DRAM processes. Then, the cell contact resistance and $t_{WR}$ (write recovery time) of the devices were measured and analyzed. The experimental results showed that the cell contact resistance was more significantly increased for higher temperature of oxidation, longer time of oxidation, and higher concentration of ozone in the oxidation furnace. In addition, the TEM cross-sectional micrographs clearly showed that the oxide layer at the interface between the landing polycrystalline silicon layer and the plug polycrystalline silicon layer was increased by the ozone oxidation. Furthermore, the rate of the device failure due to too large write recovery time was also found to be well correlated with the increase of the cell contact resistance.

• Korean Journal of Artificial Intelligence
• /
• v.11 no.1
• /
• pp.9-15
• /
• 2023

As mobile devices such as smartphones, tablets, and kiosks become increasingly prevalent, there is growing interest in developing alternative input systems in addition to traditional tools such as keyboards and mouses. Many people use their own bodies as a pointer to enter simple information on a mobile device. However, methods using the body have limitations due to psychological factors that make the contact method unstable, especially during a pandemic, and the risk of shoulder surfing attacks. To overcome these limitations, we propose a simple information input system that utilizes gaze-tracking technology to input passwords and control web surfing using only non-contact gaze. Our proposed system is designed to recognize information input when the user stares at a specific location on the screen in real-time, using intelligent gaze-tracking technology. We present an analysis of the relationship between the gaze input box, gaze time, and average input time, and report experimental results on the effects of varying the size of the gaze input box and gaze time required to achieve 100% accuracy in inputting information. Through this paper, we demonstrate the effectiveness of our system in mitigating the challenges of contact-based input methods, and providing a non-contact alternative that is both secure and convenient.

• Nuclear Engineering and Technology
• /
• v.56 no.8
• /
• pp.3450-3462
• /
• 2024

This paper presents a computational framework for drop time assessment of a control element assembly (CEA) under fuel assembly (FA) deformations. The proposed framework consists of three key components: 1) finite element modeling of CEA, 2) fluid-structure interaction to compute drag force, and 3) modeling of frictional contact between CEA and FA. Specially, to accommodate the large motion of CEA, beam elements based on absolute nodal coordinate formulation (ANCF) are adopted. The continuity equation is utilized to calculate the drag force, considering flow changes in the cross-sectional area during the CEA drop. Lastly, beam-inside-beam frictional contact model is employed to capture practical contact conditions between CEA and FA. The proposed framework is validated through experiments under two scenarios: free falls of CEA within FA, encompassing undeformed and deformed scenarios. The experimental validation of the framework demonstrated that the drop time of CEA can be accurately predicted under the complex coupling effects of fluid and frictional contact. The drop times of the S-shaped deformation case is longer than those of the C-shaped deformation case, affirming the time delay due to frictional force. The validation confirms the potential applicability to access the safety and reliability of nuclear power plants under extreme conditions.

• Journal of the Korean Society of Food Culture
• /
• v.38 no.6
• /
• pp.442-455
• /
• 2023

This study investigated the effects of pectinase treatment and skin contact time on the quality characteristics of Dae-hong peach wine. Wine was produced with variations in enzyme treatment and skin contact time (1 hour, 2 hours, 1 day, 2 days, and until the completion of fermentation). Enzyme treatment increased the production yield by 6%, as well as ethanol and redness levels, compared to the non-treated control. Volatile components were higher when the skin contact time was 2 hours or 1 day. Results were compared according to enzyme treatment and skin contact time and found to be influenced by methanol and 3-methyl-1-butanol. Enzyme treatment effectively enhanced yields and volatile compound contents. However, skin contact should be concluded a day before 1 day to ensure compliance with methanol legislative requirements. Therefore, our findings show that enzymatic treatment with shorter skin contact time preserves the distinctive characteristics of Dae-hong peaches and ensures the production of safe and flavorful wine.

• Proceedings of the KSR Conference
• /
• 2005.11a
• /
• pp.191-196
• /
• 2005

In this study, to describe vehicle-track-bridge dynamic interaction phenomena with 1/4 vehicle model, nonlinear Hertzian contact spring and nonlinear contact damper are introduced. In this approach external loads acting on 1/4 vehicle model are self weight of vehicle and geometry information of running surface. The constraint equation on contact surface is implemented by Penalty method. Also, to improve the numerical stability and to maintain accuracy of solution, the artificial damper and the reaction from constraint violation are introduced. A nonlinear time integration method, in this study, Newmark method is adopted for both equations of vehicles and structure. And to reduce the error caused by inadequate time step size, adaptive time-stepping technique is partially introduced. As the nonlinear Hertzian contact spring has no resistance to tensile force, the bouncing phenomena of wheelset can be described. Thus, it is expected that more versatile dynamic interaction phenomena can be described by this approach and it can be applied to various railway dynamic problems.

• Progress in Superconductivity and Cryogenics
• /
• v.15 no.4
• /
• pp.10-14
• /
• 2013

We have clearly investigated with respect to the survival of the insulator at cryogenic temperature under the electrical stress. The breakdown and voltage-time characteristics of turn-to-turn models for point contact geometry and surface contact geometry using copper multi wrapped with polyimide film for an HTS transformer were investigated under AC and impulse voltage at 77 K. Polyimide film (Kapton) 0.025 mm thick is used for multi wrapping of the electrode. As expected, the breakdown voltages for the surface contact geometry are lower than that of the point contact geometry, because the contact area of the surface contact geometry is lager than that of the point contact geometry. The time to breakdown t50 decreases as the applied voltage is increased, and the lifetime indices increase slightly as the number of layers is increased. The electric field amplitude at the position where breakdown occurs is about 80 % of the maximum electric field value. The relationship between survival probability and the electrical stress at cryogenic temperature was evident.

• Journal of Korean Physical Therapy Science
• /
• v.18 no.2
• /
• pp.29-40
• /
• 2011

Purpose: The purpose of this study was to analyze the changes of parameters of foot contact by various carrying a pack methods during walking. Method: The subjects were consisted of normal forty four persons (males 30, females 14, mean age 23). The carrying a pack methods were classified into five conditions: carrying no bag(Con 1), carrying a backpack(Con 2), carrying a shoulder bag(Con 3), carrying a cross bag(Con 4), carrying a one-hand bag(Con 5). All subjects were participated in these five condition and measured foot pressure by F-scan system during walking. Then foot contact time, foot contact area, foot contact length and width were measured and analyzed. The repeated one-way analysis of variance (ANOVA) was used to get difference between conditions and independent t-test was used to get difference between left and right foot within condition. Result: In the comparison of parameters of foot, contact time, contact area and mid foot width were significantly different between conditions(p<.05), and in both foot contact time at condition 5 showed the most significant reduction(p<.05). In the comparison of parameters of foot between left and right foot within condition, every conditions were not significantly different(p>.05). Conclusion: In this study various carrying methods changed the parameters of foot contact and showed significant difference in some articles between carrying methods. However, asymmetric load of pack by carrying methods didn't affected symmetry of parameters of foot contact between left and right foot.

• The Journal of Korean Physical Therapy
• /
• v.2 no.1
• /
• pp.75-83
• /
• 1990

The purpose of this study was to determine if any differences exist in eye contact before and after vestibulaar stimulation in mentally retarded children. The subjects of this study were 20 mentally retarded children with a mean age of 9 years and 8 months and a mean intelligence quotient of $30.4{\pm}9.1$. Vestibular stimulation was given for 15 minutes, 5 times a week, for 4 weeks from September 1 to September 30, 1989. Equipment used included a rocking-horse, see-saw and scooter board. Two testers used a digital watch calibrated to 1/100 second to measure object-eye contact duration and the Blocks and Shapes test for determining frequency of object-eye contact in the subjects. The results of this study were as follows : 1. There was a significant prolongation in the duration of eye contact after 15 minutes of vestibular stimulation (p<0.005). 2. There was no significant difference in duration of eye-object contact between the first and last vestibular stimulation. 3. There was no significant difference in the length of time of attention paid to objects (frequency of eye-object contact) before and after 15 minutes of vestibular stimulation on the first vestibular stimulation. 4. There was no significant difference in the frequency of eye-object contact between the first and first vestibular stimulation. In conclusion, there was u significant improvement in duration of eye-object contact on intrasession measurement in mentally retarded children. However, there was no significant improvement over time after 4 weeks of vestibular stimulation on intersession measurement. Nor was there any statistically significant improvement in frequency of eye-object contact over time during the study period.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.65 no.8
• /
• pp.1442-1449
• /
• 2016

This paper proposes a diagnosis to detecting poor contact fault and fault location. Electrical fire by poor contact fault of power cable occupied a large proportion in the total electrical installations. The proposed method has an object to prevent electrical fault in advance. But detecting poor contact fault is difficult to detect fault type and fault location by using conventional reflectometry due to faults generated intermittently and repeatedly on the time change. Therefore, in this paper poor contact fault and fault conditions were defined. System generating poor contact fault produced for the experimental setup. SSTDR and algorithm of reference signal elimination heighten performance detecting poor contact fault on live power cable. The diagnosis methods of signal process and analysis of reflected signal was proposed for detecting poor contact fault and fault location. The poor contact fault and location had been detected through proposed diagnosis methods. The fault location and error rate of detection were verified detecting accuracy by experiment results.