• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.100-101
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• 2012

The plasma damage free and room temperature processedthin film deposition technology is essential for realization of various next generation organic microelectronic devices such as flexible AMOLED display, flexible OLED lighting, and organic photovoltaic cells because characteristics of fragile organic materials in the plasma process and low glass transition temperatures (Tg) of polymer substrate. In case of directly deposition of metal oxide thin films (including transparent conductive oxide (TCO) and amorphous oxide semiconductor (AOS)) on the organic layers, plasma damages against to the organic materials is fatal. This damage is believed to be originated mainly from high energy energetic particles during the sputtering process such as negative oxygen ions, reflected neutrals by reflection of plasma background gas at the target surface, sputtered atoms, bulk plasma ions, and secondary electrons. To solve this problem, we developed the NBAS (Neutral Beam Assisted Sputtering) process as a plasma damage free and room temperature processed sputtering technology. As a result, electro-optical properties of NBAS processed ITO thin film showed resistivity of $4.0{\times}10^{-4}{\Omega}{\cdot}m$ and high transmittance (>90% at 550 nm) with nano- crystalline structure at room temperature process. Furthermore, in the experiment result of directly deposition of TCO top anode on the inverted structure OLED cell, it is verified that NBAS TCO deposition process does not damages to the underlying organic layers. In case of deposition of transparent conductive oxide (TCO) thin film on the plastic polymer substrate, the room temperature processed sputtering coating of high quality TCO thin film is required. During the sputtering process with higher density plasma, the energetic particles contribute self supplying of activation & crystallization energy without any additional heating and post-annealing and forminga high quality TCO thin film. However, negative oxygen ions which generated from sputteringtarget surface by electron attachment are accelerated to high energy by induced cathode self-bias. Thus the high energy negative oxygen ions can lead to critical physical bombardment damages to forming oxide thin film and this effect does not recover in room temperature process without post thermal annealing. To salve the inherent limitation of plasma sputtering, we have been developed the Magnetic Field Shielded Sputtering (MFSS) process as the high quality oxide thin film deposition process at room temperature. The MFSS process is effectively eliminate or suppress the negative oxygen ions bombardment damage by the plasma limiter which composed permanent magnet array. As a result, electro-optical properties of MFSS processed ITO thin film (resistivity $3.9{\times}10^{-4}{\Omega}{\cdot}cm$, transmittance 95% at 550 nm) have approachedthose of a high temperature DC magnetron sputtering (DMS) ITO thin film were. Also, AOS (a-IGZO) TFTs fabricated by MFSS process without higher temperature post annealing showed very comparable electrical performance with those by DMS process with $400^{\circ}C$ post annealing. They are important to note that the bombardment of a negative oxygen ion which is accelerated by dc self-bias during rf sputtering could degrade the electrical performance of ITO electrodes and a-IGZO TFTs. Finally, we found that reduction of damage from the high energy negative oxygen ions bombardment drives improvement of crystalline structure in the ITO thin film and suppression of the sub-gab states in a-IGZO semiconductor thin film. For realization of organic flexible electronic devices based on plastic substrates, gas barrier coatings are required to prevent the permeation of water and oxygen because organic materials are highly susceptible to water and oxygen. In particular, high efficiency flexible AMOLEDs needs an extremely low water vapor transition rate (WVTR) of $1{\times}10^{-6}gm^{-2}day^{-1}$. The key factor in high quality inorganic gas barrier formation for achieving the very low WVTR required (under ${\sim}10^{-6}gm^{-2}day^{-1}$) is the suppression of nano-sized defect sites and gas diffusion pathways among the grain boundaries. For formation of high quality single inorganic gas barrier layer, we developed high density nano-structured Al2O3 single gas barrier layer usinga NBAS process. The NBAS process can continuously change crystalline structures from an amorphous phase to a nano- crystalline phase with various grain sizes in a single inorganic thin film. As a result, the water vapor transmission rates (WVTR) of the NBAS processed $Al_2O_3$ gas barrier film have improved order of magnitude compared with that of conventional $Al_2O_3$ layers made by the RF magnetron sputteringprocess under the same sputtering conditions; the WVTR of the NBAS processed $Al_2O_3$ gas barrier film was about $5{\times}10^{-6}g/m^2/day$ by just single layer.

• Journal of Preventive Medicine and Public Health
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• v.38 no.2
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• pp.208-214
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• 2005

Objectives: This study was performed to examine the factors affecting re-smoking in male workers. Methods: A self-administrated questionnaire survey was conducted during April 2003 to examine the smoking state of 1,154 employees of a company that launched a smoking cessation campaign in1998. Five hundred and eighty seven persons, who had stopped smoking for at least one week, were selected as the final study subjects. This study collected data on smoking cessation success or failure for 6 months, and looked at the factors having an effect on re-smoking within this period. This study employed the Health Belief Model as its theoretical basis. Results: The re-smoking rate of the 587 study subjects who had stopped smoking for at least one week was 44.8% within the 6 month period. In a simple analysis, the re-smoking rates were higher in workers with a low age, on day and night shifts, blue collar, of a low rank, where this was their second attempt at smoking cessation and for those with a shorter job duration (p<0.05). Of the cues to action variables in the Heath Belief Model, re-smoking was significantly related with the perceived susceptibility factor, economic advantages of smoking cessation among the perceived benefits factor, the degree of cessation trial's barrier of the perceived barriers factor, smoking symptom experience, recognition of the degree of harmfulness of environmental tobacco smoke and the existence of chronic disease due to smoking (p<0.05). In the multiple logistic regression analysis for re-smoking, the significant variables were age, perceived susceptibility for disease, economic advantages due to smoking cessation, the perceived barrier for smoking cessation, recognition on the degree of harmfulness of environmental tobacco smoke, the existence of chronic disease due to smoking and the number of attempts at smoking cessation (p<0.05). Conclusion: From the result of this study, for an effective smoking ban policy within the work place, health education that improves the knowledge of the adverse health effects of smoking and the harmfulness of environmental tobacco smoke will be required, as well as counter plans to reduce the barriers for smoking cessation.

• Geomechanics and Engineering
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• v.13 no.2
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• pp.269-284
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• 2017

A new technique is proposed to obtain more effective screening efficiency against the ground vibration using intermittent geofoam (IF) in-filled trench. The numerical analysis is performed by employing two-dimensional finite element method under dynamic condition. Vertically oscillated strip foundation is considered as the vibration source. In presence of the ground vibration, the vertical displacements at different locations (pick-up points) along the ground surface are captured to determine the amplitude reduction factor (ARF), which helps to assess the efficiency of the vibration screening technique. The efficiency of IF over continuous geofoam (CF) in-filled vibration barriers is assessed by varying the geofoam density, the location of trench and the frequency of excitation. The results from this study indicate that a significant reduction in ARF can be achieved by using intermittent geofoam as compared to continuous geofoam. Further, it is noticed that the efficiency of IF increases with an increase in the frequency of the vibrating source. These encouraging results put forward the potential of utilising intermittent geofoam as a vibration screening material.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.1
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• pp.157-165
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• 2001

We analyzed the electrical characteristics of platinum silicide schottky junction to develope the voltage swing in Integrated Schottky Logic gates, and simulated the characteristics with the programs in this junctions. Simulation programs for analytic characteristics are the Medichi tool for device structure, Matlab for modeling and SUPREM V for fabrication process. The silicide junctions consist of PtSi and variable silicon substrate concentrations in ISL gates. Input parameters for simulation characteristics were the same conditions as process steps of the device farications process. The analitic electrical characteristics were the turn-on voltage, saturation current, ideality factor in forward bias, and has shown the results of breakdown voltage between actual characteristics and simulation characteristics in reverse bias. As a result, the forward turn-on voltage, reverse breakdown voltage, barrier height were decreased but saturation current and ideality factor were increased by substrates increased concentration variations.

• Journal of Korea Multimedia Society
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• v.3 no.5
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• pp.535-541
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• 2000

In this paper, we analyzed the characteristics of schottky junction to develop the voltage swing of ISL, and simulated the characteristics with the programs at this junctions. Simulation programs for analytic characteristics are the SUPREM V, SPICE, Medichi, Matlab. The schottky junction is rectifier contact between platinum silicide and silicon, the characteristics with programs has simulated the same conditions. The analytic parameters were the turn-on voltage, saturation current, ideality factor in forward bias, and has shown the results of breakdown voltage between actual characteristics and simulation characteristics in reverse bias. As a result, th forward turn-on voltage, reverse breakdown voltage, barrier height were decreased but saturation current and ideality factor were increased by substrates increased concentration variations.

• YAKHAK HOEJI
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• v.50 no.2
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• pp.124-128
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• 2006

Astrocyte has emerged as an active regulator of brain function, which connects between blood vessels and neurons as well as is a structural component of the blood-brain barrier, From its structural characteristics, astrocyte seems to sensitively respond to oxygen tension, and, in turn, generate diverse cellular cascades. Therefore, to reveal astrocytlc events by oxygen change, we screened genes whose expressions are upregulated under reoxygenation after hypoxic stress using cDNA representational difference analysis (RDA) technique. Meteorin that regulates glial differentiation was isolated from primary cultured rat astrocytes as a hypoxia/reoxygenation regulatory factor. We cloned rat version of Meteorin (rMe-teorin) and determined full-size sequences of rMeteorin. In addition, RT-PCR analysis revealed that Meteorin was increased under reoxygenation in astrocytes and highly expressed in the developing brain. Collectively, these results suggest that Meteorin may regulate astrocyte-mediated effects in response to the change of oxygen tension in the pathophysiological states.

• BMB Reports
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• v.51 no.2
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• pp.59-64
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• 2018

The airway epithelium is the first place, where a defense mechanism is initiated against environmental stimuli. Mucociliary transport (MCT), which is the defense mechanism of the airway and the role of airway epithelium as mechanical barriers are essential in innate immunity. To maintain normal physiologic function, normal oxygenation is critical for the production of energy for optimal cellular functions. Several pathologic conditions are associated with a decrease in oxygen tension in airway epithelium and chronic sinusitis is one of the airway diseases, which is associated with the hypoxic condition, a potent inflammatory stimulant. We have observed the overexpression of the hypoxia-inducible factor 1 (HIF-1), an essential factor for oxygen homeostasis, in the epithelium of sinus mucosa in sinusitis patients. In a series of previous reports, we have found hypoxia-induced mucus hyperproduction, especially by MUC5AC hyperproduction, disruption of epithelial barrier function by the production of VEGF, and down-regulation of junctional proteins such as ZO-1 and E-cadherin. Furthermore, hypoxia-induced inflammation by HMGB1 translocation into the cytoplasm results in the release of IL-8 through a ROS-dependent mechanism in upper airway epithelium. In this mini-review, we briefly introduce and summarize current progress in the pathogenesis of sinusitis related to hypoxia. The investigation of hypoxia-related pathophysiology in airway epithelium will suggest new insights on airway inflammatory diseases, such as rhinosinusitis for clinical application and drug development.

• Journal of Mushroom
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• v.12 no.2
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• pp.77-81
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• 2014

Mushrooms are considered not only as food but also for source of physiologically beneficial medicines. The culinary-medicinal mushrooms may important role in the prevention of age-associated neurological dysfunctions, including Alzheimer's and Parkinson's diseases. Hericium erinaceus (H. erinaceus), is edible mushrooms, is a parasitic fungus that grows hanging off of logs and trees and well established candidate for brain and nerve health. H. erinaceus contains high amounts of antioxidants, beta-glucan, polysaccharides and a potent catalyst for brain tissue regeneration and helps to improve memory and cognitive functions. Its fruiting bodies and the fungal mycelia exhibit various pharmacological activities, including the enhancement of the immune system, antitumor, hypoglycemic and anti-aging properties. H. erinaceus stimulates the synthesis of Nerve Growth Factor (NGF) which is the primary protein nutrient responsible for enhancing and repairing neurological disorders. Especially hericenones and erinacines isolated from its fruitin body stimulate NGF, synthesis. This fungus is also utilized to regulate blood levels of glucose, triglycerides and cholesterol. H. erinaceus can be considered as useful therapeutic agents in the management and/or treatment of neurodegeneration diseases. However, this review focuses on in vitro, in vivo and clinical trials for neurodegerative disease.

• New & Renewable Energy
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• v.2 no.3
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• pp.31-36
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• 2006

Superstrate pin amorphous silicon thin-film(a-Si:H) solar cells are prepared on $SnO_2:F$ and ZnO:Al transparent conducting oxides(TCO) in order to see the effect of TCO/p-layers on a-Si:H solar cell operation. The solar cells prepared on textured ZnO:Al have higher open circuit voltage VOC than cells prepared on $SnO_2:F$. Presence of thin microcrystalline p-type silicon layer(${\mu}c-Si:H$) between ZnO:Al and p a-SiC:H plays a major role by causing improvement in fill factor as well as $V_{OC}$ of a-Si:H solar cells prepared on ZnO:Al TCO. Without any treatment of pi interface, we could obtain high $V_{OC}$ of 994mV while keeping fill factor(72.7%) and short circuit current density $J_{SC}$ at the same level as for the cells on $SnO_2:F$ TCO. This high $V_{OC}$ value can be attributed to modification in the current transport in this region due to creation of a potential barrier.

• Women's Health Nursing
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• v.13 no.2
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• pp.98-104
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• 2007

Purpose: The purpose of this study was to explore the barriers and the enhancing factors and predictors to postpartum care performance. Methods: The Research design in this study was a cross-sectional correlational survey. Subjects were 145 women at 6 to 10 weeks post delivery at an OB & GY clinic. Data was gathered with postpartum care performance, and other related variables including emotional status during pregnancy, fatigue, health recovery status, maternal role and identity. Data was analyzed using the SPSS WIN(version 11.0) program. Results: The mean score of postpartum care performance was 3.08 of 5, it had significant differences in emotional status during pregnancy, coincidence of expected sex, health recovery status, postpartum fatigue and postpartum depression. The maternal role and health recovery status were enhancing factors of postpartum care performance. Also, the barrier factors were fatigue, depression and coincidence of expected sex. Among these factors, the present health recovery status had an predictability of 11.7%, postpartum fatigue 3.2%, and coincidence of expected sex 2.5%, for a total predictability factor of 17.4% on postpartum care performance. Conclusion: Among these related factors to postpartum care performance, present health recovery status was the most predictable factor and then postpartum fatigue, and coincidence of expected sex. We need to establish a strategy to reduce postpartum fatigue and implement nursing interventions for health related consequences in postpartum women.