• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.3 no.2
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• pp.18-24
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• 2010

On-board spectrophotometer has been widely used as a non-contact and non-destructive measurement system in many fields. In this study, we evaluated the effect with respect to the light of on-board spectrophotometer based on a comparison with the standard spectrophotometer and color information coordinate system. Red, yellow, green and blue color paper, which were the standard reflective color paper and Munsell color paper, were used for experiments. In order to compare between a standard spectrophotometer system and an on-board spectrophotometer system, each color paper was measured 20 times. We concluded that it is possible to develop a system regardless the effect of light if the light was supplied consistently and a calibration was performed exactly while we applied an on-board spectrophotometer to non-contact and non-destructive measurement system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.995-999
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• 1995

In spindle-bearing system, the displacement characteristics of the bearing by the load applied on the spindle are affected greatly by the assembling tolerance between the spindle and housing assembled to support the bearing. Also in spindle system of rotational operation, the compliance characteristic of the bearing is expected to be varied frequently by the thermal deformation of the spindle and the housing. To predict the thermal deformation of the spindle including heat generation of the bearing, we need to examine the effect on the compliance of spindle-bearing system by the assembling tolerance. In this paper, we proposed the load-displacement relation expression considering the effect which the variation of contact pressure due to the radial directional assembling tolerance between the bearing and the housing influences on the axial and radial directional displacement characteristics of the bearing. Furthermore, for several assembling systems of bearings and housings having all different assembling tolerances, we proposed a method to predict exactly the variation of the bearing preload which is sensitive to the thermal deformation by showing the propriety with experimental results.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.4 no.3
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• pp.185-193
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• 2000

A water treatment agent with antimicrobial activity(Ag-Os) was created by exchanging silver ion($Ag^{+}$) on calcined oyster shell powder. The desorption of the exchanged silver ion was negligible, thereby indicating a stable antimicrobial water treatment agent. The sterilization effect of Ag-Os on underwater microorganisms was then investigated. An MIC (Minimum Inhibitory Concentration) test result indicated that Ag-Os had an excellent sterilization effect on G-germs, such as Escherichia coli and Pseudomonas aeruginosa. Most germs were annihilated with an Ag-Os concentration of 200 ppm and contact time of 60 minutes. The sterilization effect was mainly dependent on the contact time. The zeta potential of the Ag-Os powder adsorbed on sand was measured relative to the concentration of exchanged silver ion. As the concentration of the exchanged silver ion increased, the surface charge density of the anions on the surface of the Ag-Os powder adsorbed on sand also increased. Accordingly, this result indicated that a higher silver ion than ion exchange capacity was present on the particle surface due to adsorption. Consequently, this increased concentration of exchanged silver ion would appear to significantly enhance the sterilization power.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.4
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• pp.570-577
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• 2002

Charged liquid particle's behavior in electric and flow field was simulated to define the effect of electric field on the contact area and its dispersion. For the simulation of flow and electric field finite volume method was applied. To find out the particle's moving path in that field lagrangian equation of motion was solved by Runge-Kutta methods. We assumed that the particle was charged 10% of Rayleigh limit while the particle passing through the electrode and the particle does not have an effect on the electric field. In case of 30[Kv] of voltage charging the particles injected from the central 60% of the nozzle injection area adhere to the grounded moving plate and no dispersion occurred. Increasing the charged voltage to 40[Kv], it brought about the same phenomena as that of 30[Kv] charging except the dispersion. Voltage increasing from 30[Kv] to 40 [Kv] caused higher Coulomb force acts on the particle and it made the particle dispersion.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.8 s.173
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• pp.27-33
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• 2005

Polishing pads play an important role in chemical mechanical polishing(CMP) which has recently been recognized at the most effective method to achieve global planarization. In this paper, we have investigated CMP characteristics as a change of groove density of polishing pads. The parameter $(K_n)$ is proposed to estimate groove density of pad. The $K_n$ is defined as groove area divided by pitch area. As the groove density value increased, removal rate increased to some point and then gradually saturated in case of increasing the groove density excessively. In addition Within wafer non-uniformity(WIWNU) worse as groove density increased excessively, although WIWNU improved as groove density increased. Also the uniformity of temperature of pad surface decreased as the groove density increased. It was because that the cooling effect increased as groove density increased. In other words, increasing the groove density which means the apparent contact area of pad has influence on amount of discharge of slurry during polishing process.

• Computers and Concrete
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• v.25 no.3
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• pp.255-266
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• 2020

This study presents comparation of fixed and viscos boundary condition effects on three-dimensional earthquake response and performance of a RCC dam considering linear and non-linear response. For this purpose, Cine RCC dam constructed in Aydın, Turkey, is selected in applications. The Drucker-Prager material model is considered for concrete and foundation rock in the nonlinear time-history analyses. Besides, hydrodynamic effect was considered in linear and non-linear dynamic analyses for both conditions. The hydrodynamic pressure of the reservoir water is modeled with the fluid finite elements based on the Lagrangian approach. The contact-target element pairs were used to model the dam-foundation-reservoir interaction system. The interface between dam and foundation is modeled with welded contact for both fixed and viscos boundary conditions. The displacements and principle stress components obtained from the linear and non-linear analyses are compared each other for empty and full reservoir cases. Seismic performance analyses considering demand-capacity ratio criteria were also performed for each case. According to numerical analyses, the total displacements and besides seismic performance of the dam increase by the effect of the viscous boundary conditions. Besides, hydrodynamic pressure obviously decreases the performance of the dam.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.12
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• pp.2019-2028
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• 1997

It has been well established that resistant force and wear that occur during rolling motion depend on several factors such as material type, hardness, subsurface microstructure, applied load, and speed. The purpose of this work is to investigate the effect of microstructure and the state of deformed layer on the rolling contact characteristics in dry and lubricated rolling contacts. The results of this work show that the rolling resistance behavior depends on the state of the deformed layer. Also, lubrication can reduce the plastic flow at the surface but may still have an effect on the subsurface strain. The cross-sectional view of the microstructure shows that surface traction has a difinite effect on the morphology of the surface region. That is, significant slip seems to have taken place between the ball than those of the dry rolling case. The surface generation effects were significantly less compared to the case of dry rolling contact.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.6
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• pp.521-526
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• 2005

Within wafer non-uniformity(WIWNU) improves as the stiffness of pad decrease. We designed the pad groove to study of pad stiffness on WIWNU in Chemical mechanical polishing(CMP) and measured the pad stiffness according to groove width. The groove influences effective pad stiffness although original mechanical properties of pad are unchanged by grooving. Also, it affects the flow of slurry that has an effect on the lubrication regime and polishing results. An Increase of the apparent contact area of pad by groove width results in decrease of effective pad stiffness. WIWNU and profile of removal tate improved as effective pad stiffness decreased. Because grooving the pad reduce its effective stiffness and it makes slurry distribution to be uniform. Futhermore, it ensures that pad conforms to wafer-scale flatness variability. By grooving the top pad, it is possible to reduce its stiffness and hence reduce WIWNU and edge effect.

• The Journal of Korean Medicine
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• v.28 no.4
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• pp.18-26
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• 2007

Objective : To study the effect of the Insamyangyoung-tang(ISYT) extract on the skin barrier function, the skin pH, skin humidity and transepidermal water loss(TEWL) were measured and histological changes were observed in DNCB(2,4-dinitrochloro-benzen)-induced contact dermatitis(CD) hairless mice. Methods : The male hairless mice were divided into three groups. Each group consisted of 15 mice. The normal group which had acetone- olive oil applied. The control group which had intentionally induced CD by DNCB and it was fed normal saline orally. The ISYT group which had intentionally induced CD by DNCB and it was fed ISYT extract orally for 7 days. The three groups were checked 24h, 48h and 72h later after inducing CD, and the skin pH, skin humidity and TEWL were observed. Tissue samples were taken, and damage to the epithelial cell was observed. Statistical analysis was performed by using one way-ANOVA: significance was set at p values less than 5% (p<0.05). Results : ISYTextract efficiently maintained the pH balance, it kept the skin humidity at a normal level, and it inhibited TEWL of the DNCB-induced CD hairless mouse. The damage to the epithelium was decreased and the regeneration power of the skin was increased in the ISYT group. Conclusion : Insamyangyoung-tang has a good effect on the skin barrier function of DNCB induced contact dermatitis hairless mice.

• Korean Journal of Applied Biomechanics
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• v.24 no.3
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• pp.209-216
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• 2014

The purpose of this study was to explore the effect of 8 weeks after school classes of track sports on students' start motion through kinematic variables. 30 students in D National university of education participated for this study. These students divided into two groups, 17 students for experimental group and 13 students for control group. The two groups participated in general athletic class as common class, and the experimental group participated in after school class additionally. The general class taught track and jump skill for 3 hours a week, and the after school class taught only athletic running skill for 30 minutes a week. Pre and post test assessed to assess students' kinematic changes. Findings indicated that velocity and step rate were increased, and contact time, step length, displacement of center of mass were decreased in the experimental group. In the control group, early velocity, knee/hip angle velocity were increased, and contact time, step length, displacement of center of mass were decreased. In conclusion, the students who only participated in general class, could not maintain athletic skills obtained from the class. However, students who participated in both general and after school class accomplish athletic start skill. This is because Continuous learning effect helped students keep the skill and did not lose the skill. Thus, in order for students to learn specific sport skills, joining after school class with general class together is recommended.