• Journal of the Korea Institute of Building Construction
• /
• v.20 no.1
• /
• pp.11-18
• /
• 2020

Carbon nanotubes are used in various industries with their excellent mechanical properties and electrical conductivity. In the construction industry, research is being conducted to give self-sensing capabilities to structures, but the results of experiments vary among researchers, and the analysis is insufficient. Therefore, in this study, the hydration and electrical properties of MWCNT-added cement pastes were measured. The electrical resistance values of hydration heat, porosity, Rietveld quantitative analysis, compressive strength, and distance were measured.. The heat resistance, porosity, Rietvelt quantitative analysis, compressive strength and distance were measured according to electrical resistance. Experimental results showed that the heat of hydration decreased with increasing MWCNT. XRD Rietveld quantitative analysis showed that there was no significant difference in the amount of hydration products with increasing addition rate of MWCNT. As a result of SEM analysis, the MWCNT is agglomerated by van der Waals forces, and this area is considered to be caused by voids and weak areas. The electrical resistance value decreases as the addition rate is increased, and thus may play a role for magnetic sensing in the future.

• Composites Research
• /
• v.33 no.2
• /
• pp.61-67
• /
• 2020

Preforming is crucial in resin transfer molding process using woven fabric. When shear deformation exceeds the locking angle, wrinkles are generated in the preform, which causes defects in the RTM process. Therefore, in this study, the allowable shear deformation limit of carbon fiber woven fabrics is quantified and the molding characteristics are verified using the actual fabric forming. As a result, the characteristics of creases according to the layer setups have been examined and the results have been discussed. Numerical analyses have been also performed using measured shear properties. These results have been compared with the experimental results.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.35 no.11
• /
• pp.1157-1162
• /
• 2011

The parking brake is an essential unit embedded in the track-driving motor of an excavator. The parking brake plays an important role in keeping the excavator in place not only when it is parked, but also during the digging operation. In fact, the load placed on the parking brake during the digging operation is significantly higher than the parking load, because the impact and rating loads caused by the bucket digging force cycle frequently and have very high load ranges. Therefore, the load conditions during the digging operation should be taken into account in the parking brake certification test. In this study, a series of experiments was carried out in which various operating pressures were applied to the parking brake, where repeated loads were reciprocally placed on the brake by locking the multifriction disc and releasing the hydraulic cylinder. The characteristics of the parking brake were investigated by comparing the obtained experimental results and the theoretical design specifications.

• Journal of Adhesion and Interface
• /
• v.11 no.2
• /
• pp.70-75
• /
• 2010

It described the modification of polydimethylsiloxane (PDMS) with amphiphilic methyl methacrylate-based polyethylene glycol (PMMA-b-PEG) to enhance the hydrophilicity of a PDMS surface and cytotoxicity of it. PMMA-b-PEG solutions in water/ethanol mixture was spun-cast on the PDMS surface and the surface was characterized by long-term measurement of water contact angle. The morphology of PDMS surfaces coated with PMMA-b-PEG was characterized by field emission scanning electron microscopy and atomic force microscope. Cytotoxicity of the modified surfaces was investigated by MTT assay which would be necessary for the evaluation of tissue compatibility after implantation of the materials. Based on the MTT assay, PDMS coated with PMMA-b-PEG didn't show any significant cytotoxcity.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.42 no.4 s.304
• /
• pp.21-30
• /
• 2005

In this paper, we propose lane detection and trackinB algerian using B-Snake as robust algorithm. One of chief virtues of Lane detection algorithm using B-Snake is that it is possible to specify a wider range of lane structure because B-Spline conform an arbitrary shape by control point set and that it doesn't use any camera parameter. Using a robust algorithm called CHVEP, we find the vanishing point, width of lane and mid-line of lane because of the perspective parallel line and then we can detect the both side of lane mark using B-snake. To demonstrate that this algorithm is robust against noise, shadow and illumination variations in road image, we tested this algorithm about various image divided by weather-fine, rainy and cloudy day. The percentage of correct lane detection is over 95$\%$.

• The Journal of the Convergence on Culture Technology
• /
• v.6 no.4
• /
• pp.535-543
• /
• 2020

The KSA caused an error in deriving the statistical measurement items due to the misconfiguration of the safety variables and sub-modules that constitute the safety statistics framework for external causes of death, and pathogenesis, without considering the academic classification system of the field and area of the disaster/accident. By naming it as a mechanism, it was analyzed that the result of poor statistical validity has arrived. Therefore, in this study, by changing the safety parameters according to the WHO safety definition and setting the sub-modules appropriately, the categories of falls, drowning accidents, and accidents exposed to inanimate mechanical forces are classified as accidents at industrial sites and work in daily life. As a result, by systematically re-establishing the complex group of statistical items of the NSO by deriving the field of disasters/accidents according to the nature of the source of external causes of death and setting the relevant domains academically, statistical validity gets better and It is anticipated to play an important role in determining the direction of safe investment.

• Aerospace Engineering and Technology
• /
• v.1 no.1
• /
• pp.8-27
• /
• 2002

In this study, the load analysis of a composite canard aircraft is performed numerically. Excel visual basic program for PC is used to calculate aerodynamic coefficients, loads and moments etc.. The basic data required for the load analysis such as aircraft configuration and dimension, parts and its weight and coordinate etc. are obtained from Catia modeling, measurement or material density. Aircraft weight, center of gravity, inertia moment, structural design speeds, wing load distribution, forces and moments are evaluated by using these data. V-n diagram is also represented for selecting critical loads applied to the wing and fuselage. The V-n diagram is investigated to decide the flight envelope of canard aircraft for design speed VA, VC, VD and load factor +3.8G, -1.52G at maximum weight of 2,573 lbs and sea level. In the future, the results of the wing and fuselage load analysis is to represented by using selected critical loads.

• Journal of Navigation and Port Research
• /
• v.41 no.6
• /
• pp.389-394
• /
• 2017

In this paper, the captive model test of a submarine using the RA test was carried out in a square basin. The target model submarine consisted of four types varying according to the position of conning tower and control planes. Hydrodynamic derivatives were acquired by multi-regression analysis. As a result, horizontal dynamic stability indexes of the four types presented positive values and satisfied dynamic stability requirements. In addition, the stability index of type 1 and type 4 - each with the same cruciform configuration of the aft planes - scored within the acceptable range of motion stability.

• Journal of Biomedical Engineering Research
• /
• v.24 no.4
• /
• pp.309-318
• /
• 2003

In this paper a 6 degree-of-freedom robot was studied for medical purpose. In the past the robot used for industry field was utilized for medical robot but in these days the robot used for rehabilitation. welfare, and service. This system was Proposed for a stroke patient or a patient who can not use one arm. A master-slave system was constructed to exercise either paralysis or abnormal arm using normal arms movement. Study on the human body motion result was applied to calculate a movement range of humans elbow and shoulder. In addition, a force-torque sensor is applied to estimate the rehabilitation extent of the patient in the slave robot. Therefore, the stability of the rehabilitation robot could be improved. By using the rehabilitation robot, the Patient could exercise by himself without any assistance In conclusion. the proposed system and control algorithm were verified by computer simulation and system experiment.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.4
• /
• pp.1509-1514
• /
• 2011

The core of IT products, electronic components, especially the MLCC, chip inductors, chip Varistors and so on. In order to test the electrical characteristics of the chip using the Reno-pin contact test method has been used. In current chips, mass production of semiconductor manufacturing processes, high-speed production test for the chip speed up, precision is required. But Vibration displacement is a very short, so in order to overcome these shortcomings, the displacement amplification to design the structure has been actively studied. In this paper, a building structure with a flexible hinge was designed amplification instrument, semiconductor chip industry in the performance test and inspection equipment to measure the electrical characteristics of high speed linear actuators Reno-Pin using system was developed.