• Journal of the Korea Safety Management & Science
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• v.11 no.1
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• pp.67-73
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• 2009

The goal of this study was to assess the level of vibration in an walking-type cultivator, and to provide a basic information to manage the vibration exposure for farmers. The latent periods of vibration-induced white finger (VWF) were assessed through analyzing the vibration levels and frequency characteristics. Also, vibration acceleration levels based on the daily vibration exposure duration was suggested. The latent periods of vibration-induced white finger were assessed by ISO 5349 method. The latent periods were 4.5 and 10.1 years at 10% and 50% of farmer group, respectively. Also, under ACGIH (American Conference of Governmental Industrial Hygienists) standard, daily vibration exposure duration at 6.7 m/s2 of vibration acceleration has to be less than 4 hours. Therefore, education that maximum working hours should be less than 4 continuous hours is necessary for the operators of walking-type cultivators.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.137-140
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• 2000

Synthesis of a new copoly (M4Ch-ChMA), copoly ((4-methacryloyloxy) chalcone-cholestery methacrylate), with chalconyl and cholesteryl moiety characteristics for photoalignment materials was investigated. Good thermal stabilities of the synthesized copolymers are confirmed by thermogravimetric analysis (TGA) measurement. The pretilt angles of the nematic liquid crystal (NLC) are reduced as UV exposure time is increased on the copolymer surfaces. A pretilt angle of 81$^{\circ}$ in NLC was observed with UV exposure of 3 min on the copolymer-3 surface. The NLCs pretilt angle is attributable to increased chalcone with increasing the UV exposure time.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.561-565
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• 1999

We measured the optical properties in Ag/chalcogenide films with the exposure of 325nm-Held laser In addition we have investigated the Ag doping mechanism as considering the changes of Ag-concentration distribution and optical energy gap ( $E_{op}$ ) with Photon-dose. The "windows" characteristics of Ag thin film occur around the wavelength of 325 nm and the Ag is evaluated to be transparent, without an absorption, in the region. While the $E_{op}$ of S $b_2$ $S_3$ thin film was changed largely by an exposure of HeNe laser(632.8 nm) an exposure of HeCd laser resulted in relatively small variation of $E_{op}$ . Therefore it is thought that photon absorption at the metal layer plays an important role in Ag photodoping.on at the metal layer plays an important role in Ag photodoping.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.502-505
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• 2003

We synthesized high thermal photoalignment material with hydroxyl aromatic polyimide, and studied the liquid crystal (LC) aligning capabilities on the photopolymer layers. Also, electro-optical (EO) performances for the twisted-nematic (TN)-liquid crystal display (LCD) photoaligned with linearly polarized UV exposure were investigated. A good LC alignment with UV exposure on the photopolymer surface can be obtained. However, the low pretilt angles were obtained below $1^{\circ}$. The Voltage-transmittance (V-T) curve without backflow bounce in the photoaligned TN cell with UV exposure was observed. The response time of photoaligned TN cell was measured about 24 ms.

• Journal of the Optical Society of Korea
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• v.5 no.1
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• pp.16-19
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• 2001

A photopolymer, copoly (M4Ch-ChMA), copoly ((4-methacryloyloxy) chalcone-cholesteryl methacrylate), was synthesized in this study. The electro-optical (EO) characteristics for the photo-aligned vertical-alignment (VA)-liquid crystal display (LCD) were investigated. Excellent voltage-transmittance curves for the VA-LCD photo-aligned by polarized UV exposure on the copoly (M4Ch-ChMA) surface were observed. The response time for the photo-aligned VA-LCD decrease with increasing UV exposure time. consequently, the photo-dimerized chalcone moiety increased with increasing UV exposure time, which then contributed to a low response time for the VA-LCD photo-aligned.

• Journal of Life Science
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• v.7 no.3
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• pp.212-218
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• 1997

The studies were conducted to explore the dffects of growth or survival against various factors and plasmid profiles of 49 Y. enterocolitica isolated from springs water. In the presence of calcium hypochlorite, y. enterocolitica was entirely extinguished by exposure for 33 hours at 0.8 ppm concentration, and was grown up to 7% NaCl, but not at 95 NaCI. Y. enterocolitica was presented optimal growth at pH 7.0 anad 9.0, and not allowth the growth at pH3.0, 5.0 and 11.0. The optimal temperature for growth of Y. enterocolitica was 25$\circ$C and 35$\circ$C, and allowed the growth at refrigerant temperature, 5$\circ$C. Y. enterocolitica was remarkably decreased by exposure for 30 seconds under UV light, and entirely extinguished by exposure for 90 seconds. Therefore, UV light was effective for sterilization of Y. enterocolitica. Fourty-nine strains of Y. enterocolitica were harbor plasmid DNA of approximately 46 Kb molecular weight.

• Clinical and Experimental Pediatrics
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• v.64 no.1
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• pp.3-11
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• 2021

There is a growing body of literature on the adverse health effects of ambient air pollution. Children are more adversely affected by air pollution due to their biological susceptibility and exposure patterns. This review summarized the accumulated epidemiologic evidence with emphasis on studies conducted in Korea and heterogeneity in the literature. Based on systematic reviews and meta-analyses, there is consistent evidence on the association between exposure to ambient air pollution and children's health, especially respiratory health and adverse birth outcomes, and growing evidence on neurodevelopmental outcomes. Despite these existing studies, the mechanism of the adverse health effects of air pollution and the critical window of susceptibility remain unclear. There is also a need to identify causes of heterogeneity between studies in terms of measurement of exposure/outcome, study design, and the differential characteristics of air pollutants and population.

• The Research Journal of the Costume Culture
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• v.13 no.3 s.56
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• pp.425-438
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• 2005

This study is to examine the types of expression and aesthetic characteristics of on-line game characters by analyzing those game characters' body and their costume that appear in various domestic on-line game sites. It is shown in this study that types of the human bodies and costume expressed through the game characters are grouped into five categories such as exposure and tightness, enlargement and exaggeration, curtailment and simplification, gender stereotype and unification. Furthermore, there are four typical aesthetic characteristics resulting from those types of expressions; First, 'grotesque' is expressed in the form of extreme enlargement and exaggeration, extreme exposure and concealment, combined images among human, animal or machine, or monstrous devilish images. Second, in an effort to express 'eroticism', bodies are directly exposed, see-through costumes are used in order to emphasize the body lines or very tight designs are used. Third, 'futuristic' characteristics are shown through geometrical shape and silhouette, machine-like details, strong artificial colors or glossy hi-tech material. Lastly, 'pastiche' is expressed with reconciliation of variety of costumes of game characters. Various opposite or heterogeneous styles are combined or harmonized each other to show pastiche, of which examples are male and female, superior culture and inferior one, rich and poor, oriental and western, human and machine, human and nature or past and future, etc.

• The Research Journal of the Costume Culture
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• v.14 no.6
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• pp.1042-1055
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• 2006

The purpose of this study is to consider the formative characteristics of dance sports from such points of view as shapes, colors, material and decorations, and to examine artistic characteristics that are expressed through those elements. As a result, this study shows five artistic characteristics as follows; First, rhythmic characteristic is expressed with repeat of lines that is formed by pleats, shirring or gather, with duplication of ruffle's wave, with gradation of colors, with Moire-effect that is generated with overlap of see-through material, with glossy material that reflects lights to a great extent, with fringe. Second, bodily characteristic emphasizes the beauty of human bodies through direct or indirect body exposure by way of cut-and-open, see-throughness or close adhesion. Third, decorative characteristic is shown with beads, fringe, ruffle, embroidery, shirring, binding, or feather. Fourth, the beauty of female body is manifested to express eroticism, which is culminated by body exposure, body consciousness, use of illuminating or see-through material or colorful trimming. Finally, elegant characteristic is revealed through feminity, sophistication, and harmony that are expressed with black and white colors, see-through material, or bead trimmings.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.19 no.1
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• pp.51-58
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• 2021

Chemical decontamination of primary systems in a nuclear power plant (NPP) prior to commencing the main decommissioning activities is required to reduce radiation exposure during its process. The entire process is repeated until the desired decontamination factor is obtained. To achieve improved decontamination factors over a shorter time with fewer cycles, the appropriate flow characteristics are required. In addition, to prepare an operating procedure that is adaptable to various conditions and situations, the transient analysis results would be required for operator action and system impact assessment. In this study, the flow characteristics in the steady-state and transient conditions for the chemical decontamination operations of the Kori-1 NPP were analyzed and compared via the MARS-KS code simulation. Loss of residual heat removal (RHR) and steam generator tube rupture (SGTR) simulations were conducted for the postulated abnormal events. Loss of RHR results showed the reactor coolant system (RCS) temperature increase, which can damage the reactor coolant pump (RCP)s by its cavitation. The SGTR results indicated a void formation in the RCS interior by the decrease in pressurizer (PZR) pressure, which can cause surface exposure and tripping of the RCPs unless proper actions are taken before the required pressure limit is achieved.