• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.935-938
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• 2002

The degree of contamination in outdoor insulation system is one of the most importance factor to determine the level of insulation, and the salt is known as the most dangerous contaminants in the most region of the world. In a macroscopic point of view, as shown through the preceding study, the generation and deposition of salt contaminants has a great relation with the geographical conditions and the meteorological conditions, such as, wind velocity, wind direction, precipitation and so forth. However, in the aspect of microscopic analysis, the pollution mechanism has a great relation with aerodynamic properties of insulator, originated from the profile of insulators, and the non-uniform deposition is unevitable. So, in this investigation, we had make a experiment to seize the electrical properties of non-uniformly contaminated insulator. The results of this investigation could be used as a good groundwork in the determination of outdoor insulation design.

• Journal of the Korean Chemical Society
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• v.3 no.1
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• pp.23-27
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• 1954

The relation between the height of ascending solvents and its velocity were studied with strips of Toyo No. 50 filter paper. The filter paper strip of 3cm width and cat 30 cm length is hooked down or fixed between two sheets of glass plates inside a cylinder containing the solvent, in which the lower end of the strip is dipped. As the solvents, acetone, hydrochloric acid, water or mixtures of these are used. For short time intervals, Ostwald's folmula $h = Kt^n$ was found to be most suitable to express the relation between the height of the solvent front, h, and time, t. For longer time intervals, results will be discussed in the next paper. The mean values of the constant m in the above formula for pure acetone and pure water were 0.44 and 0.485, respectively, and that of K were 0.05 and 2.4, respectively. The time interval whose the above formula applies, for each solvent was 2 hours for the former, and a half hour for the later, respectively. The movement of solutes, such as $Cu^{++}$ and $Fe^{++}$ showed that the Rf values of solutes become constant values after a long periods; e.g., ca. 6 hours with 10N-HCl-Acetone (1 : 9) solvent.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.4
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• pp.315-322
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• 2015

In this paper, the theory of rectangular plate on the elastic foundation is used to get the relation equation between the effective Young’s modulus and the ice sheet deflection by applying the characteristic length concept, since the model ice sheet is rectangular shape in KRISO (Korea Research Institute for Ships and Ocean Engineering) ice basin. The obtained relation equation is equal to that of using the circular plate theory. A device is made and used to measure the deflection of ice plate using LVDT (Linear Variable Differential Transformer) for several loading cases and the procedure of experiments measuring the deflection used for getting the Young’s modulus is explained. In addition, the flexural strength value obtained through flexural strength experiments is compared with that of finite element analysis using the obtained effective Young’s modulus. Also, a nonlinear FEA (Finite Element Analysis) of cantilever ice beam is done with eroding effect and LS-DYNA result shows the fracture of brittle ice under 1 mm/s velocity load.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.8
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• pp.7-12
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• 2010

When a vehicle is running, wheel is generating vertical and lateral force on the rail, in addition to load of vehicle, through a complicated set of motions. The derailment coefficient refers to the ratio of lateral force to vertical force(wheel load), and if the value exceeds a certain level, a wheel climbs or jumps over the rail. That's why the value is used as a criterion for running safety. Derailment coefficient of rolling stocks alters according to shape of rail track. I measured three-dimensional angular velocity and acceleration to use 3D Motion Tracker. Test result, derailment coefficient of rolling stocks and shape of rail track examined closely that have fixed relation. Specially, was proved that roll motion has the close coupling relation.

• Journal of Ocean Engineering and Technology
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• v.21 no.1 s.74
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• pp.18-24
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• 2007

When the wind blows strong, most waves are breaking at sea. Breaking waves occur by exceeding the limitation of wave steepness (wave height/wave length = 1/7). Because a wave of single angular frequency couldn't generate the breaking phenomena at a two-dimensional ocean engineering basin, the breaking wave can be generated by the superposition of waves with various angular frequencies based on dispersion relation. This study investigates the particle kinematics in the breaking wave and the magnitude of the breaking wave exciting force at the breaking point and breaking region. We compare the regular wave load in a regular wave, which has same specifications (wave height, period and length), with the breaking waveload. Also, the experimental results of wave exciting force and particle velocity are investigated, by comparison with the analytic results using the potential theory.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.141.2-141.2
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• 2012

We present photometric solutions of the 26,212 eclipsing binaries discovered in the LMC by Graczyk et al. (2011). They published that 70 percent of a total are detached systems. Another 25 and 5 percent are semi-detached and contact binaries, respectively. We discovered that 21 percent of 26,121 eclipsing binary stars are eccentric orbit systems. The binary star distribution in the LMC is different from those of the Galactic center direction (Bade window). It is very interesting that there are only 5 of 357 (2 percent) stars have eccentric orbit in the Galactic Center (Kang 2011). We selected the light curve of 18,274 detached systems. Then we estimated the fundamental parameters on the basis of their photometric solutions and the semi-major-axis (a) assuming the distance modulus to the LMC~18.50. We compared the estimated fundamental parameters with an empirical mass-luminosity relation and consistency between mass-radius relation base on stellar evolution model in the low metallicity (Z=0.008) by Bertelli et al. (2009). This method allows for independent determine of the fundamental parameters of the eclipsing binaries in the LMC without the radial velocity curves.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.03a
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• pp.619-626
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• 2002

In this study, a correlation among pressure, time and quantity of injection was organized from the laboratory tests, which were executed many times representing in-situ soil conditions carefully and then it would be applied to the in-situ soil injection simulator which will be developed for optimal injection into the ground. The sort of sample soils were both sand(A specimen) and silty sand(B specimen). Injection tests were gone into operation by compaction state, injection velocity and the depth individually. In the ground improved with permeation Infection, the relation among injection pressure of the same depth, the injected quantities and time were systematic by the depth. By defining the limit range of injection pressure and quantity about the variety of a linear equation obtained from lining each of their trend, the application of laboratory injection monitoring program and the data to evaluate its realization were produced. In the ground improved with root type injection, the relation between injection pressure and the injected quantities was irregular because fracture state occurred quickly.

• Proceedings of the KIEE Conference
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• 2004.05b
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• pp.173-175
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• 2004

The degree of contamination on outdoor insulators is one of the most importance factor to determine the pollution level of outdoor insulation. Outdoor insulators in coastal are affected due to salty wind blowing from the seaside. The sea salt is known as the most dangerous pollutant. As known through the preceding study, the generation of salt pollutant and the pollution degree of outdoor insulators have a close relation in accordance with meteorological conditions, such as temperature, humidity, dewpoint, wind velocity and wind direction. Therefore, at first, we have analyzed relation between meteorological conditions and contaminants for development of prediction method. In this paper, we have investigated a statistical estimation technique based on actual data for equivalent salt deposit density(ESDD) of outdoor insulators which were installed in Kochang field test substation with multiple linear regression analysis.

• Korean Institute of Interior Design Journal
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• v.17 no.4
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• pp.84-91
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• 2008

The objective of this study is to investigate how visitors' behavior change in relation to the pattern of exhibition in art museum. For the purpose Busan Museum of Modern Art was selected as the sample in this study. And two patterns of exhibition, namely the planar exhibition and the three dimensional exhibition, were surveyed using the tracking movement method. The data gathered from random-sampling 60 visitors in a art museum was analyzed by the correlation analysis and T-test. The results are as follows; 1) There is no meaningful difference in visitors' behavior by the exhibition pattern in terms of their viewing area, viewing time, viewing distance, viewing velocity, viewing rate. 2) In contrast, there is meaningful difference in terms of the number of stops by visitors and the time spent without movement to see the objects; visitors stopped more often and stayed longer within the three dimensional exhibition space than the planar exhibition in a art museum. In sum, visitors extrinsically show no big behavioral difference between the planar exhibition and the three dimensional exhibition, but much difference in the way they communicate with objects; they show more active behavior within the three dimensional exhibition space.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.06a
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• pp.55-63
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• 2001

Friction and wear properties of brake friction materials containing different metal fibers (Al, Cu or Steel fibers) were investigated using a pad-on-disk type friction tester. Two different materials(gray iron and Al-MMC)) were used for disks rubbing against the friction materials. Results from ambient temperature tests revealed that the friction material containing Cu fibers sliding against cast iron disk showed a distinct negative ${\mu}$-ν (friction coefficient vs. sliding velocity) relation implying possible stick-slip generation at low speed. The negative ${\mu}$-ν relation was not observed when the Cu-containing friction materials were rubbed against the. Al-MMC counter surface. As applied loads increased, friction materials showed higher friction coefficients comparatively. Friction materials slid against cast iron disks exhibited higher friction coefficients than Al-MMC disks during high temperature tests. On the other hand, high temperature test results suggested that copper fibers in the friction material improved fade resistance and the steel fibers were not compatible with Al-MMC disks showing severe material transfer and erratic friction behavior during sliding at elevated temperatures.