• Journal of the Korean Society of Industry Convergence
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• v.1 no.1
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• pp.21-30
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• 1998

The purpose of this study is to clarify the floor temperature on the human body and to estimate thermal comfort zone in a heated room. In order to evaluate the effects of floor heating, a series of experiments were carried out using Korean subjects. The following experiments were conducted: 1) to obtain the effective radiation area and configuration factors of the person in the sitting posture on a floor to get the mean radiant temperature, 2) to measure contacted area of the person to the floor to calculate conduction heat rate, 3) to measure convective heat transfer coefficient of the body and 4) to know the thermal comfort zone of indoor environment heated by ON-DOL. Subjects were exposed to the following conditions: combinations of air temperature $20^{\circ}C$, $22.5^{\circ}C$, $25^{\circ}C$, and floor temperature $20^{\circ}C$, $22.5^{\circ}C$, $25^{\circ}C$, $27.5^{\circ}C$, $30^{\circ}C$, $32.5^{\circ}C$, $35^{\circ}C$, $37.5^{\circ}C$, $40^{\circ}C$ under still air and 50% relative humidity in the controllable artificial climate chamber. To evaluate the effect of heat conduction between the body and a floor modified mean skin temperature was defined. Weighting coefficient to calculate mean skin temperature were modified with the contacted area. The experiments revealed a positive correlation between the modified operative temperature and the modified mean skin temperature. The modified mean skin temperature can indicate the effect of heat conduction between body and a floor surface.

• Transactions of Materials Processing
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• v.28 no.3
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• pp.145-153
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• 2019

The objective of this study is to analyze the mechanical splicing characteristic of the threaded bar according to the contact conditions of the transverse rib. In order to consider the contact conditions of the rib, selection of the main variables including the gap of the core diameter ($l_c$), rib angle (${\theta}$), and the number of contacts ($C_N$) of transverse rib was done. So as to analyze the splicing characteristic of the D51 threaded bar, a finite element (FE) simulation of the tensile test was conducted using the designed D51 threaded bar and coupler. Through FE simulation results, it was verified that the mechanical slicing characteristics varied based on the main design variables ($l_c$, ${\theta}$, and $C_N$). It was further confirmed that it was important to determine the $C_N$ in consideration of $l_c$. Additionally, the tensile test results of the D25 and D51 threaded bar combined with the couplers were similar to FE simulation results. Furthermore, to quantitatively evaluate FE simulation and test results, the calculation equation for the contacted projection area ratio (R) of the transverse rib was proposed. To secure a mechanical splicing joint of the threaded bar, it was established that the R calculated using the proposed equation had to be greater or equal to 40%.

• Journal of Preventive Medicine and Public Health
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• v.46 no.3
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• pp.147-154
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• 2013

Objectives: Many epidemiological studies have suggested that a variety of medical illnesses are associated with suicide. Investigating the time-varying pattern of medical care utilization prior to death in suicides motivated by physical illnesses would be helpful for developing suicide prevention programs for patients with physical illnesses. Methods: Suicides motivated by physical illnesses were identified by the investigator's note from the National Police Agency, which was linked to the data from the Health Insurance Review and Assessment. We investigated the time-varying patterns of medical care utilization during 1 year prior to suicide using repeated-measures data analysis after adjustment for age, gender, area of residence, and socioeconomic status. Results: Among 1994 suicides for physical illness, 1893 (94.9%) suicides contacted any medical care services and 445 (22.3%) suicides contacted mental health care during 1 year prior to suicide. The number of medical care visits and individual medical expenditures increased as the date of suicide approached (p<0.001). The number of medical care visits for psychiatric disorders prior to suicide significantly increased only in 40- to 64-year-old men (p=0.002), women <40 years old (p=0.011) and women 40 to 64 years old (p= 0.021) after adjustment for residence, socioeconomic status, and morbidity. Conclusions: Most of the suicides motivated by physical illnesses contacted medical care during 1 year prior to suicide, but many of them did not undergo psychiatric evaluation. This underscores the need for programs to provide psychosocial support to patients with physical illnesses.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.33 no.6
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• pp.203-211
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• 1984

MOS silicon solar cells have been developed using the fixed (interface) charge inherent to thermally oxidized silicon to induce an n-type inversion layer in 1-10 ohm-cm p-type silicon. Higher collection efficiencies are predicted than for diffused junction cells. Without special precautions a conversion efficiency of 14.2% is obtained. A MOS silicon solar cell is described in which an inversion layer forms the active area which is then contacted by means of a MOS grid. The highest efficiency is obtained when the resistivity of the substrate is high.

• Korean Journal of Computational Design and Engineering
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• v.18 no.1
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• pp.1-9
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• 2013

Nowadays in order to perform assembly process planning by using CAPP (Computer Aided Process Planning), researches to generate the assembly sequence automatically have come under constant interest by many researchers and they are devoted to optimize the assembly sequence. In this paper, the product on analyzing the relationship between assembled parts via contacting information such as common area, automatically based on the liaison graph of the product. To verify the validness and efficiency of the approach, the simple product is tested in the experimental way.

• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.2
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• pp.346-363
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• 2015

We have performed integrated dynamics modeling for a supercavitating vehicle. A 6-DOF equation of motion was constructed by defining the forces and moments acting on the supercavitating body surface that contacted water. The wetted area was obtained by calculating the cavity size and axis. Cavity dynamics were determined to obtain the cavity profile for calculating the wetted area. Subsequently, the forces and moments acting on each wetted part-the cavitator, fins, and vehicle body-were obtained by physical modeling. The planing force-the interaction force between the vehicle transom and cavity wall-was calculated using the apparent mass of the immersed vehicle transom. We integrated each model and constructed an equation of motion for the supercavitating system. We performed numerical simulations using the integrated dynamics model to analyze the characteristics of the supercavitating system and validate the modeling completeness. Our research enables the design of high-quality controllers and optimal supercavitating systems.

• Journal of radiological science and technology
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• v.8 no.2
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• pp.71-72
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• 1985

This study was performed on the dose distribution of various field size and the effect of penumbra shield in the telecobalt unit. The results obtained are as follows. 1. Errors of the light and ${\gamma}-ray$ field size was below the regulation as 0.52 percentage. 2. The coefficient of field area was increased with the larger field area, and this coefficient was showed the more difference in larger SSD. 3. The rectangular field areas, which were described by level of the same percentage depth does, were decreased with the more elongation factor. At the same elongation factor, the compensating factor was decreased with the larger field size. 4. The lead block or extension collimator was able to shield r-ray exposure of outside field size from 50 to 80 percentage. 5. On the matching adjacent fields, while the gap between beam edges are contacted, that overlapped beam edges indicated up to 140 percentage, and while the gap was 1 cm, it could be reduced to 90 Percentage. The lead-libocking on the overlapped area was more effective to lower dose, as 80 percentage in this case. 6. Percentage depth dose of various trimming field sizes were increased linearlly according to area 1 perimeter size, but the center split field size did not maintain linearlly.

• Journal of Ocean Engineering and Technology
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• v.28 no.5
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• pp.423-428
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• 2014

Ice loads may be conveniently categorized as local ice loads and global ice loads. Local ice loads are often defined as ice pressures acting on local areas of shell plates and stiffeners. Therefore, local ice loads are defined in all ice class rules. However, directly measuring the local ice pressure using the actual ice class vessel is a very difficult task because appropriate instruments for direct measurement must be installed on the outer hull, and they are easily damaged by direct ice contacts/impacts. This paper focuses on the estimation of the local ice pressure using the data obtained from icebreaking tests in the Arctic sea in 2010 using the Korean icebreaking research vessel (IBRV) ARAON. When she contacted the sea ice, the local deformation of the side shell was measured by the strain gauges attached to the inside of the shell. Simultaneously, the contact area between the side shell and sea ice is investigated by analyzing the distribution of the measured strain data. Finally, the ice pressures for different contact areas are estimated by performing a structural analysis.

• Tribology and Lubricants
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• v.25 no.2
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• pp.86-95
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• 2009

Adhesion tests were carried out in order to investigate the effect of temperature on the adhesion behavior between a PMMA film and a fused silica lens in the micro scale. For the tests, a microtribometer system was specially designed and constructed. The pull-off forces on the PMMA film were measured under atmospheric condition as the temperature of the PMMA film was increased from 300 K to 443 K and decreased to 300 K. The contact area between the PMMA film and the lens was observed during the test. The adhesion behavior was changed with the change of the PMMA surface state as the temperature increased. In glassy state below 363 K, the pull-off force did not change with the increase of temperature. In rubbery state from 383 K to 413 K, the pull-off force increased greatly as the temperature increased. In addition, the area of contact was enlarged. In viscous state above 423 K, the fingering instability was observed in the area of contact when the PMMA film contacted with the lens. It was also found that the adhesion behavior can be varied with the thermal history of the PMMA film. The residual solvent in the PMMA film could emerge to the PMMA surface due to the heating and reduced the pull-off force.

• Journal of Biosystems Engineering
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• v.16 no.3
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• pp.211-218
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• 1991

In this study, the break of the rotary blade which is occured from a stress concentration of the inside of blade by the outside impulsive load, is analyzed to 3-dimension used by the Freezing Photoelastic Method. These results are as follows. 1. The bending and compression stress are the greatest at the location of blade case. 2. The section area of 3cm-location from the blade case is the smallest, therefore, there are breaked 58% of all at this location and are proofed to the most danger section 3. The section area which by stress concentration of 3cm-location from blade case is caused by the production of blade, and it was higher danger of break than another location's. 4. In the location of 6cm and 9cm from the blade case, the bending stress has received a little and the section area has larger than another's, so it is not almost possible that the break at that location 5. In order to prevent of break, the external part which has contacted soil have to made tender for receiving a little stress and the internal part which received a large stress have to strengthen.