• Transactions on Electrical and Electronic Materials
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• v.7 no.4
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• pp.167-172
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• 2006

Submicron colloidal silica coated with ceria were prepared by mixing of silica and nano ceria particles and modified by hydrothermal reaction. The polishing efficiency of the ceria coated silica slurry was tested over oxide film on silicon wafer. By changing the polishing pressure in the range of $140{\sim}420g/cm^2$ with the ceria coated silica slurries in $100{\sim}300nm$, rates, WIWNU and friction force were measured. The removal rate was in the order of 200, 100, and 300 nm size silica coated with ceria. It was known that the smaller particle size gives the higher removal rate with higher contact area in Cu slurry. In the case of oxide film, the indentation volume as well as contact area gives effect on the removal rate depending on the size of abrasives. The indentation volume increase with the size of abrasive particles, which results to higher removal rate. The highest removal rate in 200 nm silica core coated with ceria is discussed as proper combination of indentation and contact area effect.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.6
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• pp.561-565
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• 2007

Because of a good wear resistance and a stable contact resistance, Ag-CdO is widely used as electrical contact material. But, the Cd-oxide mainly exists as a coarse particle and adversely affected to environment. As a reason, $Ag-SnO_2$ alloy has been developed. The Sn-oxide maintains stable and fine particle even at high temperature. In order to investigate the effect of Misch metal (Mm) additional that affects the formation of the oxide and the formation of fine matrix Ag, we studied the microstructures and properties of Ag-Sn-In(-Mm) material fabricated by rapid solidification process. The experimental procedure were melting using high frequency induction, melt spinning, and internal oxidation. The Mm addition makes Ag matrix more fine than no Mm addition. The reason is that the addition of Misch metal decreased a latent heat of fusion of alloy, as a result the rapid solidification effect of alloy is increased. The maximum hardness shows at 0.3 wt%Mm. after that the hardness is decreased until 0.4 wt% Mm, but still larger than no Mm addition alloy. At 0.5 wt% Mm alloy, the precipitation of Misch metal causes a decrease of hardness than no Mm addition alloy.

• Transactions on Electrical and Electronic Materials
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• v.18 no.4
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• pp.225-228
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• 2017

In this study, zinc tin oxide (ZTO) films were prepared on indium tin oxide (ITO) glasses and annealed at different temperatures under vacuum to investigate the correlation between the Ohmic/Schottky contacts, electrical properties, and bonding structures with respect to the annealing temperatures. The ZTO film annealed at $150^{\circ}C$ exhibited an amorphous structure because of the electron-hole recombination effect, and the current of the ZTO film annealed at $150^{\circ}C$ was less than that of the other films because of the potential barrier effect at the Schottky contact. The drift current as charge carriers was similar to the leakage current in a transparent thin-film device, but the diffusion current related to the Schottky barrier leads to the decrease in the leakage current. The direction of the diffusion current was opposite to that of the drift current resulting in a two-fold enhancement of the cut-off effect of leakage drift current due to the diffusion current, and improved performance of the device with the Schottky barrier. Hence, the thin film with an amorphous structure easily becomes a Schottky contact.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1145-1150
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• 2005

The aim of this paper is to investigate the effect of surface texturing on metal surface and to understand the potential of friction reduction through micro-scale dimple to fabricate by photolithography on pin-on-disk test using flat-on-flat contact geometry. It was verify that the friction property with respect to the same pitch has been influence on the size of dimple under lubricated sliding contact. Also, we can recognize from Stribeck curve that the friction property has a connection with the size of dimple. It can explain a relationship between the friction coefficient and a dimensionless parameter for lubrication condition. The friction property has been an effect on the size of surface texture on reduction friction, not only because the density of dimple, but also because the ratio of diameter/pitch. This ratio of approximately 0.5 is recommend under the tested friction condition. It suggested that the ratio of d/p is an important parameter for surface texture design.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.217-222
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• 2004

The aim of this paper is to investigate the effect of micro-dimple size on reduction friction and to understand the potential of friction reduction through micro-scale dimple to fabricate by photolithography on pin-on-disk test using flat-on-flat contact geometry. It was verify that the friction property with respect to the same pitch has been influence on the size of dimple under lubricated sliding contact. Also, we can recognize from Stribeck curve that the friction property has a connection with the size of dimple. It can explain a relationship between the friction coefficient and a dimensionless parameter for lubrication condition. The friction property has been an effect on the size of surface texture on reduction friction, not only because the density of dimple, but also because the ratio of diameter/pitch. This ratio of approximately 0.5 is recommend under the tested friction condition. It suggested that the ratio of d/p is an important parameter for surface texture design.

• Korean Journal of Human Ecology
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• v.12 no.5
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• pp.713-735
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• 2003

The purpose of this study was to investigate the effects of the characteristics of maternal social networks on maternal expectation for their own children to examine the path that social networks had an effect on the self-esteem and the emotional intelligence of children through maternal expectation for their own children. The data used in this study were collected from 524 fourth to sixth graders and their mothers residing in Daejeon using structured questionnaire. The major findings of the study were as follows : (1) Among social network characteristics, proportion of friends and neighbors, proximity, direction and interference had a negative effect, and proportion of mothers of child's friends, frequency of contact, intimacy, emotional support, service support had a positive effect on maternal expectation for their own children. (2) Among social network characteristics, proportion of mothers of child's friends had a direct effect and proportion of friends, neighbors, and mothers of child's friends, proximity, frequency of contact, intimacy, direction, emotional support, service support, and interference had an indirect effect on children's emotional intelligence through maternal expectation for their own children. (3) Among social network characteristics, proportion of kin and mothers of child's friends, intimacy, service support, material support and interference had a direct effect, and proportion of neighbors and mothers of child's friends, proximity, frequency of contact, direction, service support had an indirect effect on children's emotional intelligence through maternal expectation for their own children.

• The Journal of the Korea Contents Association
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• v.21 no.5
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• pp.465-476
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• 2021

This study considers both causal and control factors for explaining both contact and distribution of sexually explicit material and tests their interaction effects for examining buffering effects of control factors in causal process. This study examines the effect of low self-control, differential association with peers and patriarchy family environmental factor as causal factors. It also considers three control factors such as morality. legal punishment, and lack of opportunity and test interaction effect between causal and control factors in both contact and distribution cases. Using data from college students in Seoul, results show that the effects of all causal factors are significant in both contact and distribution of sexually explicit material and the effect of differential association is the most significant. However, their interaction effects between causal and control factors are different across contact and distribution cases. In the contact case, all interaction effects are not significant. It means that causal factors have independent effects and control factors have no buffering effects. However, in the distribution case, the interaction effects between low self-control and morality, between differential association and morality, between patriarchy family and punishment, and between patriarchy family and lack of opportunity are significant. Empirical implications are discussed.

• Korean Journal of Materials Research
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• v.12 no.12
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• pp.918-923
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• 2002

In this work, CdTe films were deposited on CdS/ITO/glass substrate by a close spaced sublimation (CSS) method. A $Cu_2$Te layer was deposited on the CdTe film by evaporating $Cu_2$Te powder. Then the samples were annealed for p+ ohmic contact. TEM and XRD analysis showed that $CdTe/Cu_2$Te interface exhibited different forms with various annealing temperature. A good p+ ohmic contact was achieved when the annealing temperature was between $180^{\circ}C$ to $200^{\circ}C$. Best cell efficiency of 12.34% was obtained when post annealing temperature was $200^{\circ}C$ for 5 min. Thermal stress test of the CdS/CdTe cells with carbon back contact showed that the $Cu_2$Te contact was stable at $50^{\circ}C$ in $N_2$ and was slowly degraded at $100^{\circ}C$ in $N_2$. In comparison to the conventional carbon contact, the $Cu_2$Te contact showed a better thermal stability.

• Journal of The Korean Society of Integrative Medicine
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• v.8 no.4
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• pp.307-321
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• 2020

Purpose : A person infected by SARS-CoV2 may present various symptoms such as fever, pain in lower respiratory tract, and pneumonia. Measuring body temperature is a simple method to screen patients. However, changes in the surrounding environment may cause errors in infrared measurement. Hence, a non-contact thermometer controls this error by setting a correction value, but it is difficult to correct it for all environments. Therefore, we investigate device error values according to changes in the surrounding environment (temperature and humidity) and propose guidelines for reliable patient detection. Methods : For this study, the temperature was measured using three types of non-contact thermometers. For accurate temperature measurement, we used a water bath kept at a constant temperature. During temperature measurement, we ensured that the temperature and humidity were maintained using a thermo-hygrometer. The conditions of the surrounding environment were changed by an air conditioner, humidifier, warmer, and dehumidifier. Results : The temperature of the water bath was measured using a non-contact thermometer kept at various distances ranging from 3~10 cm. The value measured by the non-contact thermometer was then verified using a mercury thermometer, and the difference between the measured temperatures was compared. It was observed that at normal surrounding temperature (24 ℃), there was no difference between the values when the non-contact thermometer was kept at 3 cm. However, as the distance of the non-contact thermometer was increased from the water bath, the recorded temperature was significantly different compared with that of mercury thermometer. Moreover, temperature measurements were conducted at different surrounding temperatures and the results obtained significantly varied from when the thermometer was kept at 3 cm. Additionally, it was observed that the effect on temperature decreases with an increase in humidity Conclusion : In conclusion, non-contact thermometers are lower in lower temperature and dry weather in winter.

• Journal of the Health Care and Life Science
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• v.9 no.2
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• pp.245-252
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• 2021

We surveyed the lecture types and campus lifes which college students preferred during COVID-19 Pandemic situation. Students who attend colleges in Gwangju city, Jeonnam and Jeonbuk province, answer a questionnaire. The principal result of the survey showed that all grades preferred un-contact lecture but nevertheless also preferred the compound method of contact and un-contact lecture(p=0.923). In educational satisfaction degree by lecture type, the degree of satisfaction for contact lecture ranked highest at 2.82(p=0.000). But the survey showed the degree was not a variable which had a significant effect on the improvement of scholastic performance(p=0.325). The questionnaire analysis shows that students demand un-contact lecture high because of infection risk, but they wish the un-contact lecture which can solve problems in real time rather than the recorded lecture. As a result of this study, instructor is highly required to prepare un-contact teaching plans which reflect the demands of students.