• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.8
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• pp.731-736
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• 2016

Three-dimensional (3D) high-aspect-ratio (HAR) microstructures for biomedical applications (e.g., microneedle, microadhesive, etc.) are microfabricated using the hybrid ultraviolet (UV) lithography in which inclined, rotational, and reverse-side UV exposure processes are combined together. The inclined and rotational UV exposure processes are intended to fabricate tapered axisymmetric HAR microstructures; the reverse-side UV exposure process is designed to sharpen the end tip of the microstructures by suppressing the UV reflection on a bottom substrate which is inevitable in conventional UV lithography. Hybrid UV lithography involves fabricating 3D HAR microstructures with an epoxy-based negative photoresist, SU-8, using our customized UV exposure system. The effects of hybrid UV lithography parameters on the geometry of the 3D HAR microstructures (aspect ratio, radius of curvature of the end tip, etc.) are measured. The dependence of the end-tip shape on SU-8 soft-baking condition is also discussed.

• Journal of the HCI Society of Korea
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• v.9 no.1
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• pp.1-9
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• 2014

Use of smart phones and other means allowed ready access to social networking service (SNS) and its users have explosively increased. In the meantime, Facebook which has the largest user community has caused various social problems due to its conservative privacy policy; yet its users are continuously increasing and committed to the service although its privacy policy has not so much changed. In this research, we studied the irony of increasing popularity of Facebook despite its negative privacy policy in the light of its users' double-sided desire. That is, users use Facebook because they are curious about other users' personal information and activities although they are at the same time anxious about public exposure of their own personal information and activities. To test this conjecture, we investigated users' double-sided desire (privacy protection, viewing others' activities) using questionnaire and reverse scenario test and confirmed that proper balance of privacy protection and activity exposure is an important contributor to continued popularity of Facebook. Much research studied SNS focusing on self-presentation that is on the side of self-exposure. This research highlights the importance of balance keeping between hide-and-seek for SNS companies such as Facebook in the use of privacy policy.

• Korean Journal of Environmental Agriculture
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• v.19 no.2
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• pp.154-159
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• 2000

This study was carried out to elucidate the symptom of leaf injury to ozone and to determine varietal difference to ozone injury in rice and soybean plant. Ozone was produced by electrostatic discharge in oxygen and was monitored by UV absorption ozone analyzer. The rice leaves were spotted red and rolling leaf edge, discolored to reddish brown or yellowish white in response to ozone, and the leaves that were severely stressed were withered from the tip of leaf. The soybean ones were also discolored to lemon yellow, yellow or dark brown. The leaf injury in both rice and soybean was clearly appeared at the reverse side of leaf and in lower leaves. Milyang 23 and Nonganbyeo among rice cultivars tested were resistant to ozone, but Chucheongbyeo was resistant to it. The ratio of leaf injury was increased and chlorophyll content was decreased as the extension of ozone exposure from 2 to 8 hours in rice. Keunolkong and Danyeopkong among soybean cultivars tested showed resistant reaction to ozone, but Kwangankong and Muhankong were susceptible to it. It was observed that the soybean plants grown for 45 days after seeding were severely damaged by ozone than those of other growth stages.

• Journal of the Korean Society of Costume
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• v.56 no.9 s.109
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• pp.14-23
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• 2006

The purpose of this study is to identify the esthetic features of femme fatale character fashions, which are shown in Movie . The feature of evil femineity is the attribute of evil which brings men to ruin by the dangerous, cunning, and cruel trick, and is expressed in black color, red color, and slash fashion. This fashion shows the dark reverse side of women's sexual desire in relation to anxiety, evil, and death. The feature of sensuality evokes physical pleasures or desires, and maximizes the exposure of sexual regions by tightening or loosening women's body. In the fashion expressing this feature, the forms are fit or loose silhouette. and the colors are black and red. and the materials are soft. This fashion seems to deconstruct the past concept of sex consciousness and emphasize the independent and autonomous femineity. The feature of positiveness combines feminine elements with masculine elements in relation to power elements. This feature is expressed in tailored suit and trousers, with few patterns and details, and in black color and gray color. This fashion reflects the aggressive, challenging, and independent femineity, and expresses the potential defense for the weakness and danger of female body. The feature of purity expresses the earnest and truthful mind, and is expressed in the soft and light one-piece dress, the elegant suit, and the pink color and black color fashion. This fashion shows angel-like and reliable womanly beauty, but at the same time shows women's attribute which changes their behavior and thinking every moment, so that this fashion shows women's double-sided attribute which combines women's weakness and violence, or tenacity and conflict.

• The Journal of Korean Society for Radiation Therapy
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• v.27 no.1
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• pp.87-95
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• 2015

Purpose : This study presents the usefulness assessment of secondary shield for the lens exposure dose reduction during radiation treatment of peripheral orbit. Materials and Methods : We accomplished IMRT treatment plan similar with a real one through the computed treatment planning system after CT simulation using human phantom. For the secondary shield, we used Pb plate (thickness 3mm, diameter 25mm) and 3 mm tungsten eye-shield block. And we compared lens dose using OSLD between on TPS and on simulation. Also, we irradiated 200 MU(6 MV, SPD(Source to Phantom Distance)=100 cm, $F{\cdot}S\;5{\times}5cm$) on a 5cm acrylic phantom using the secondary shielding material of same condition, 3mm Pb and tungsten eye-shield block. And we carried out the same experiment using 8cm Pb block to limit effect of leakage & transmitted radiation out of irradiation field. We attached OSLD with a 1cm away from the field at the side of phantom and applied a 3mm bolus equivalent to the thickness of eyelid. Results : Using human phantom, the Lens dose on IMRT treatment plan is 315.9cGy and the real measurement value is 216.7cGy. And after secondary shield using 3mm Pb plate and tungsten eye-shield block, each lens dose is 234.3, 224.1 cGy. The result of a experiment using acrylic phantom, each value is 5.24, 5.42 and 5.39 cGy in case of no block, 3mm Pb plate and tungsten eye-shield block. Applying O.S.B out of the field, each value is 1.79, 2.00 and 2.02 cGy in case of no block, 3mm Pb plate and tungsten eye-shield block. Conclusion : When secondary shielding material is used to protect critical organ while irradiating photon, high atomic number material (like metal) that is near by critical organ can be cause of dose increase according to treatment region and beam direction because head leakage and collimator & MLC transmitted radiation are exist even if it's out of the field. The attempt of secondary shield for the decrease of exposure dose was meaningful, but untested attempt can have a reverse effect. So, a preliminary inspection through Q.A must be necessary.

• Journal of the Korean Society of Radiology
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• v.16 no.4
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• pp.435-442
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• 2022

The heel effect creates a density difference in the X-ray images because the intensity of the anode and cathode side of the X-ray tube is not equal. The purpose of this study is to evaluate the density difference due to the heel effect by rotating the step wedge by 180 degrees and then changing the distance. After fixing the tube voltage and tube current to 72 kVp and 10 mAs, the forward and reverse directions were taken using a step wedge. At this time, the distance (80 cm ~ 130 cm) was taken at 10 cm intervals, and the density value was measured by setting the region of interest for each step of the step wedge through the M6 program. First, the difference in intensity between the anode and the cathode was confirmed through the radiation exposure test. In addition, when the distance (from 80 cm to 130 cm) was changed, the difference in density between the cathode and the anode decreased as the projection distance increased. As a result, images of uniform density can be obtained as the projection distance increases.