• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.297-301
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• 2004

The optimum design against contact crack initiation is investigated to find major parameters in designing desirable surface-coated asymmetric layered components. Hard ceramic coated soft materials with various elastic modulus mismatch are prepared for the analysis. Spherical indentation is conducted for producing contact cracks from the surface or interface between the coating and the substrate layer. A finite element analysis of the stress fields in the loaded layer components enables a direct correlation between the damage patterns and the stress distributions. Implications concerning the design of asymmetric layered components indicate that the coating thickness and the elastic modulus mismatch are important parameters for designing layered component to prevent the initiation of contact cracks.

• Tribology and Lubricants
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• 제12권1호
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• pp.42-46
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• 1996

This paper deals with a numerical study of the dynamic response of rubber oil seals for rotating shaft when interference as well as static and dynamic eccentricities are present. In loss of contact conditions the dynamic curve of oil seals is numerically simulated using the FEM package MSC/NASTRAN. The direct integration method is selected to analyze the time domain response of the seal lip-shaft contact. The computed results based on the experimental data indicate that the increased rotating speed may produce the gap separation between lip edge of rubber seals and shaft. These results will be very useful in predicting the dynamic leakage due to contact behaviors of rubber oil seals under dynamic conditions.

• 대한의용생체공학회:의공학회지
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• 제38권3호
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• pp.137-141
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• 2017

The indirect-contact bio-electric measurements using capacitive electrodes show large motion artifacts in comparison with conventional direct-contact measurements. It is necessary to measure the motion artifacts quantitatively, for the researches of reducing the motion artifacts. In this study, a device for quantitative measurement of motion artifacts was built. Using the device, an electrode was rubbed against some cloth(cotton) and the voltage variation of the electrode was measured as motion artifact in several environmental conditions(temperature and relative humidity). The measured waveforms agreed with that expected by the triboelectricity and the prior observations of the motion artifacts. Therefore, the results demonstrated the usability of the measurement system built in this study. The measurement system will be a great contribution to future research for reducing motion artifact.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.163.2-163.2
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• 2014

We report catalytic decomposition of few-layer graphene on an $Au/SiO_x/Si$ surface wherein oxygen is supplied by dissociation of the native $SiO_x$ layer at a relatively low temperature of $400^{\circ}C$. The detailed chemical evolution of the graphene covered $SiO_x/Si$ surface with and without gold during the catalytic process is investigated using a spatially resolved photoelectron emission method. The oxygen atoms from the native $SiO_x$ layer activate the gold-mediated catalytic decomposition of the entire graphene layer, resulting in the formation of direct contact between the Au and the Si substrate. The notably low contact resistivity found in this system suggests that the catalytic depletion of a $SiO_x$ layer could realize a new way to micromanufacture high-quality electrical contact.

• Pediatric Infection and Vaccine
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• 제5권1호
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• pp.143-146
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• 1998

Syphilis is a systemic communicable disease caused by the motile spirochete, Treponema pallidum, which is only a natural pathogen for human. The distribution and trends of syphilis are influenced by biologic factors, sexual behaviors, biomedical technology, availability of and access to health care, public health efforts, changes in population dynamics, and sociocultural factors. Although sexual contact is the main route of transmission, Treponema pallidum may also be infected through direct contact with syphilitic lesions, blood transfusion, ingestion of menstrual blood or vaginal secretions, or transplacental transmissions. In extremely unusual circumstances, infection by means of contact with a skin lesion and human bite have been reported. We experienced a case of syphilis which is thought to be infected by the abnormal imposition of hands on a child, which caused unnecessary erosive trauma with fingernails.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.539-542
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• 2002

The role of disk clamp is to fasten disks to motor and to prevent the slip of disks during operation. This paper examined the effects of the design parameters of disk clamp - thickness, contact radius and cross-sectional shape -on the clamping force and circumferential stress distribution of disk. The large stress variation in circumferential direction results in large disk waveness and will increase repeatable run-out (RRO) finally. The disk clamp-disk-disk spacer system is modeled and the FE analysis is performed by ANSYS. The disk clamp with large contact radius shows more uniform stress distribution than the one with small contact radius and the stiffness variation around circumferential direct ion or the addition of the bending sect ion can make stress distribution uniform.

• 정보저장시스템학회논문집
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• 제3권2호
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• pp.81-85
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• 2007

Reliability of a hard disk drive depends on the head disk interface (HDI) characteristics. Particularly, the disk media and the head can be damaged due to contact between the two components during operation. The contact may occur due to particles being introduced into the disk/slider interface or due to direct contact between the slider and the disk. Such contacts may be induced by external vibration or abnormal operation of the HDI. In this work the characteristics of scratches generated on the disk surface were investigated. The scratches were generated by impacting the hard disk. The type of scratches was analyzed with respect to their shape and dimensions.

• International Journal of Air-Conditioning and Refrigeration
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• 제9권2호
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• pp.1-7
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• 2001

One of the important applications of a contact melting process is a latent thermal energy storage system owing to its high heat flux and small temperature variation. In some previous works, the split fins have been employed in order to enhance the melting rate. In the present work, the direct contact melting was experimentally investigated using an ice as specimen for both split and non-split fins. It was shown that the contact melting by split fins increases the melting rate compared to that of non-split ones.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1998년도 제13차 학술회의논문집
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• pp.20-25
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• 1998

This paper proposes a new compliant contact control strategy for the robot manipulators accidentally interacting with an unknown environment. The main features of the proposed method are summarized as follows: First, each entry in the diagonal stiffness matrix corresponding to the task coordinate in Cartesian space is adaptively adjusted during con-tact along the corresponding axis based on the contact force with its environment. Second, it can be used for both unconstrained and constrained motions without any switching mechanism which often causes undesirable instability and/or vibrational motion of the end effector. Third, the adjusted stiffness gains are automatically recovered to initially specified stiffness gains when the task is changed from constrained motion to unconstrained motion. The simulation results show the effectiveness of the proposed method by employing a two-link direct drive manipulator interacting with an unknown environment.

• 가정과삶의질연구
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• 제17권3호
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• pp.159-170
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• 1999

This study analyzes the relationships between social networks and loneliness. Subjects of this study are male and female undergraduate students residing in Soul and Jeonju city Questionaires were and the obtained results were analyzed through SPSS PC+ The results are as follows 1) The size of general social networks doesnt's show difference between male and female students but at the of intimate social networks female students' one is bigger than male students' And female students' contact frequency via telephone is higher than male students' but the direct contact frequency did not show the difference: 2) The bigger the size of social networks is and the higher the contack frequency is the more the mount of social supports female students get. And the bigger the size of social networks is the more the amount of social support male students get. But among male students there are no relationships between the contact frequency and the amount of social supports 3) The size and co tact frequency of social networks is negatively related to loneliness among female and male students 4) The amount of social supports explaines the degree of loneliness at 23% among female students and 18% among male students.