• 한국조리학회지
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• 제20권5호
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• pp.71-75
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• 2014

The purpose of this study is to verify antecedent variables that affect emotional labor. The results are as follows. First, display rules positively affected deep acting and negatively affected surface acting. Second, customer contact time positively affected deep acting but did not affect surface acting. Third, the interaction between display rules and customer contact time did not have significant effects on surface acting but negatively affected deep acting. The implications based on these results are as follows. First, theoretically, this study extends the range of leading variables that affect emotional labor and verifies the moderation effects between these variables. Next, practically, this study suggests that presenting harmonious criteria with regards to display rules and customer contact time that fit well into the concept of food service company is a very useful tool to manage emotional labor of the employees. The limitation of this study is that the causal relationship between variables demonstrated in this study cannot be generalized due to convenience sampling and cross sectional research.

• 환경위생공학
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• 제14권3호
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• pp.10-21
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• 1999

The purpose of study were to research the characteristics of water variation adding humic acids to distilled water after ozonation. Upon investigating pH variation with contact time after providing distilled water+air, distilled water+ozone and distilled water-humic acid-air in reactor, it reduced after 60 minute in inletting air and in spite of short contact time did suddenly in inletting ozone. TOC and UV-254 continued to increase with contact time of ozone and humic acids. $NH^{4+}-N$ did slowly increase or decrease after constant contact time of ozone, because $NH^{4+}-N$ was converted into $No^3-N$ by ozone. T-N did suddenly increase after 90minute, but T-P did rarely fluctuate for total experiment. Total 30 species of organic matter were detected by GS/MSD, but 14 species did really tend to increase except for matter identified in distilled water and blank test. Humic acids generated $aliphatic{\cdot}aromatic$ hydrocarbon, alcohol and amine etc., and did various matters without inflow course of contaminants.

• 전기학회논문지
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• 제62권1호
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• pp.57-62
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• 2013

Because of high torque and easiness of speed control, Direct Current(DC) motors have been used for a long time. But, its applications are limited in circumstance and performance, since they contained brush and commutator. The commutation characteristic gives effect to life and performance of the DC motor. Naturally, the commutation characteristic analysis is strongly required. In this paper, With the result of finite element analysis, The inductance is calculated each rotor position and applied to the voltage equations coupled with commutation equation. Also, contact resistances of brush/commutator assembly are considered using contact area and brush width converted with commutator segments. The time derivative term in the differential equation is solved in time difference method. This algorithm was applied to 2-pole shunt DC motor. We considered commutation characteristic by changing contact resistance between brush and commutator segment.

• 한국분무공학회지
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• 제28권3호
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• pp.113-118
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• 2023

This study investigates the evaporation characteristics of paired sessile droplets on a heated substrate. In particular, the evaporation time and contact line behaviors were analyzed based on the droplet-to-droplet distance and substrate temperature. The contact line behavior and volume variations were visualized using the shadowgraph method. It was observed that the contact diameter and contact angle exhibited similar behavior for both single and paired droplets regardless of the droplet-to-droplet distance and substrate temperature. The paired droplets demonstrated a longer evaporation time than the single droplet due to the vapor accumulation between the droplets. Furthermore, the scaled lifetime, defined as the ratio of evaporation time between paired and single droplets, increased as the droplet-to-droplet distance decreased and decreased as the substrate temperature increased, attributed natural convection.

• 대한기계학회논문집
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• 제19권5호
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• pp.1243-1250
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• 1995

For the numerical solution of frictional dynamic contact problems, correct contact points and displacements are determined by iteratively reducing the displacement error vector monotonically toward zero And spurious oscillations are prevented from the solution by enforcing the velocity and acceleration compatibilities of the contact points with the corresponding error vectors. Numerical simulations are conducted to demonstrate the accuracy of the solution and the necessity of the velocity and acceleration compatibilities on the contact surface.

• 대한기계학회논문집A
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• 제21권12호
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• pp.2029-2037
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• 1997

In a web winding process, the contact roll plays many important roles including air-entrainment control and WIT(Wound In Tension) regulation. The behavior of contact roll significantly affects the winding tension characteristics specifically at the time of contact when the speeds of contact roll and the winding roll are not synchronized. A mathematical model for the web, the winding roll, and the contact roll is derived. By using the model derived, a nonlinear PID(NPID) controller is designed to control the winding tension at the time of contact and separation between the contact roll and the winding roll. Computer simulation study showed that the performance of the winding system with the NPID controller significantly improved compared with that of a system with PID controller.

• 한국초전도ㆍ저온공학회논문지
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• 제7권2호
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• pp.21-26
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• 2005

Breakdown characteristics and survival probability of turn-to-turn models were investigated under ac and impulse voltage at 77K. For experiments, two test electrode models were fabricated: One is point contact model and the other is surface contact model. Both are made of copper wrapped by O.025mm thick polyimide film(Kapton). The experimental results were analyzed statistically using Weibull distribution in order to examine the wrapping number effects on voltage-time characteristics under ac voltage as well as under impulse voltage in LN$_{2}$. Also survival analysis were performed according to the Kaplan-Meier method. The breakdown voltages of surface contact model are lower than that of point contact model, because the contact area of surface contact model is wider than that of point contact model. Besides, the shape parameter of point contact model is a little bit larger than that of surface contact model. The time to breakdown t$_{50}$ is decreased as the applied voltage is increased, and the lifetime indices slightly are increased as the number of layers is increased. According to the increasing applied voltage and decreasing wrapping number, the survival probability is increased.

• Journal of Mechanical Science and Technology
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• 제16권10호
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• pp.1276-1286
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• 2002

The numerical techniques are presented to solve the static and dynamic contact problems of deformable bodies having large rotations of the contact surfaces. The contact conditions on the possible contact surfaces are enforced by using the contact error vector, and an iterative scheme similar to augmented Lagrange multiplier method is employed to reduce the contact error vector monotonically. For dynamic contact problems using implicit time integration, a contact error vector is also defined by combining the displacement, velocity, and acceleration on the contact surface. The suggested iterative technique is implemented to ABAQUS by using the UEL subroutine UEL. In this work, after the computing procedures to solve the frictional contact problems are explained, the numerical examples are presented to compare the present solutions with those obtained by ABAQUS.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 C
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• pp.1013-1015
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• 1995

The electrical properties of Al/TiN/Ti contact according to post anneal ins conditions are investigated at submicron contacts. $N^+$ contact resistance increases with increasing alloy temperature while $P^+$ contact resistance slightly decreases. The contact tentage current increases wi th increasing alloy temperature for both $N^+$ and $P^+$ contacts. The contact resistance and leakage current of $N^+$ contact increases with increasing alloy tide. $P^+$ contact resistance decreases with increasing alloy time but $P^+$ contact tentage current increases. The contact resistance and contact leakage current increases with increasing alloy cycles for both $N^+$ and $P^+$ contacts.

• 제어로봇시스템학회논문지
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• 제2권1호
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• pp.35-44
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• 1996

A design method for a teleoperator robot system is presented in this paper. The control system consists of two phases; approach phase and contact one. The end-effector position of the estimated slave robot and the contact force between the end-effector and wall are displayed on the monitors at control site, using which the operator controls the teleoperator system. The approach phase controller is designed using Smith's principle and the contact one designed based upon the structured singular value ${\mu}$ in order to increase the robustness of the system. The uncertainatices such as communication time delay and the variations of system parameters are considered as a muliplicative pertubation. Computer simulations are conducted in order to evaluate the performance of the proposed design method. It is found that desirable control performance, especially in the contact phase, is obtained if the control mode is switched into contact phase when the estimated position of the slave robot end-effector is in front of the wall.