• Korean Journal of Microbiology
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• v.49 no.4
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• pp.360-368
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• 2013

Recently interactive water fountains are gaining popularity in making public facilities in South Korea. The total number of interactive fountains is rapidly growing at the rate of >50% annually. In this study, we performed quantitative microbial risk assessment to estimate infection risks in children by Legionella spp. while playing in interactive fountains. The exposure dose for a given concentration of Legionella in water was calculated using water-aerosol partition rate of Legionella, exposure duration, inhalation rate, and deposit rate of aerosols in the lungs following inhalation. The dose was converted to infection risk by using the dose-response function developed for L. pneumophila. High weight and/or old children, i.e., 12-year children, running around in fountains were the highest risk group by showing >0.05 infection probability for fountain waters containing ${\geq}10^4$ CFU/L Legionella. The result supported the current guideline by Korea Centers for Disease Control and Prevention, which permits use of water with < $10^3$ CFU/L Legionella cells for all purposes. However, the results still warrant further evaluation of the guideline to accommodate risks for children because the dose-response relationship in the model was developed for healthy adults. Further risk assessment studies need to be conducted by employing dose-response model for children who generally carries weaker immune system than adults.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.184-184
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• 2012

Recently, InGaN/GaN multi-quantum well grown on GaN pyramid structures have attracted much attention due to their hybrid characteristics of quantum well, quantum wire, and quantum dot. This gives us broad band emission which will be useful for phosphor-free white light emitting diode. On the other hand, by using quantum dot emission on top of the pyramid, site selective single photon source could be realized. However, these structures still have several limitations for the single photon source. For instance, the quantum efficiency of quantum dot emission should be improved further. As detection systems have limited numerical aperture, collection efficiency is also important issue. It has been known that micro-cavities can be utilized to modify the radiative decay rate and to control the radiation pattern of quantum dot. Researchers have also been interested in nano-cavities using localized surface plasmon. Although the plasmonic cavities have small quality factor due to high loss of metal, it could have small mode volume because plasmonic wavelength is much smaller than the wavelength in the dielectric cavities. In this work, we used localized surface plasmon to improve efficiency of InGaN qunatum dot as a single photon emitter. We could easily get the localized surface plasmon mode after deposit the metal thin film because lnGaN/GaN multi quantum well has the pyramidal geometry. With numerical simulation (i.e., Finite Difference Time Domain method), we observed highly enhanced decay rate and modified radiation pattern. To confirm these localized surface plasmon effect experimentally, we deposited metal thin films on InGaN/GaN pyramid structures using e-beam deposition. Then, photoluminescence and time-resolved photoluminescence were carried out to measure the improvement of radiative decay rate (Purcell factor). By carrying out cathodoluminescence (CL) experiments, spatial-resolved CL images could also be obtained. As we mentioned before, collection efficiency is also important issue to make an efficient single photon emitter. To confirm the radiation pattern of quantum dot, Fourier optics system was used to capture the angular property of emission. We believe that highly focused localized surface plasmon around site-selective InGaN quantum dot could be a feasible single photon emitter.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.8
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• pp.76-82
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• 2016

In this paper, we evaluated shielding effectiveness (SE) of carbon nanotube (CNT) film using near field scanning (NFS) in near field analysis. We adopted CNT film with deposit carbon density of 5% and thickness of 1mm for evaluation of shielding characteristic. Using a test coupon analogized to an actual IC package, we measured SE according to measuring position and SE according to distances between the CNT film and the test coupon. As a result, the measured SE in the near field varied with frequency. Especially, the measured electric field SE in the center of the test coupon is better than that of the measured edge point of the test coupon where it is affected by fringing effect. The results show that the measured SE in the near field is affected not only by frequency but also by measurement environment such as position and height of the probe and height of shielding film. In conclusion, we should choose proper methods for SE measurement considering interference distance in the electronic control system because there is little correlation between the proposed evaluation method in the near field and ASTM D 4935-10.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.135-135
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• 2015

Tubes are of extreme importance in industries as for fluid channels or wave guides. Furthermore, some weapon systems such as cannons use the tubes as gun barrels. To increase the service life of such tubes, a protective coating must be applied to the tubes' inner surface. However, the coating methods applicable to the inner surface of the tubes are very limited due to the geometrical restriction. A small-diameter cylindrical magnetron sputtering gun can be used to deposit coating layers on the inner surface of the large-bore tubes. However, for small-bore tubes with the inner diameter of one inch (~25 mm), the magnetron sputtering method can hardly be accommodated due to the space limitation for permanent magnet assembly. In this study, a new approach to coat the inner surface of small-bore tubes with the inside diameter of one inch was developed. Instead of using permanent magnets for magnetron operation, an external electro-magnet assembly was adopted around the tube to confine the plasma and to sustain the discharge. The electro-magnet was operated in pulse mode to provide the strong axial magnetic field for the magnetron operation, which was synchronized with the negative high-voltage pulse applied to the water-cooled coaxial sputtering target installed inside the tube. By moving the electro-magnet assembly along the tube's axial direction, the inner surface of the tube could be uniformly coated. The inner-surface coating system in this study used the tube itself as the vacuum chamber. The SS-304 tube's inner diameter was 22 mm and the length was ~1 m. A water-cooled Cu tube (sputtering target) of the outer diameter of 12 mm was installed inside of the SS tube (substrate) at the axial position. The 50 mm-long electro-magnet assembly was fed by a current pulse of 250 A at the frequency and pulse width of 100 Hz and 100 usec, respectively. The calculated axial magnetic field strength at the center was ~0.6 Tesla. The central Cu tube was synchronously driven by a HiPIMS power supply at the same frequency of 100 Hz as the electro-magnet and the applied pulse voltage was -1200 V with a pulse width of 500 usec. At 150 mTorr of Ar pressure, the Cu deposition rate of ~10 nm/min could be obtained. In this talk, a new method to sputter coat the inner surface of small-bore tubes would be presented and discussed, which might have broad industrial and military application areas.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.157-157
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• 2015

Recently, the growing interest in organic microelectronic devices including OLEDs has led to an increasing amount of research into their many potential applications in the area of flexible electronic devices based on plastic substrates. However, these organic devices require a gas barrier coating to prevent the permeation of water and oxygen because organic materials are highly susceptible to water and oxygen. In particular, high efficiency OLEDs require an extremely low water vapor transition rate (WVTR) of $1{\times}10^{-6}g/m^2day$. The Key factor in high quality inorganic gas barrier formation for achieving the very low WVTR required ($1{\times}10^{-6}g/m^2day$) is the suppression of defect sites and gas diffusion pathways between grain boundaries. In this study NBAS process was introduced to deposit enhanced film density single gas barrier layer with a low WVTR. Fig. 1. shows a schematic illustration of the NBAS apparatus. The NBAS process was used for the $Al_2O_3$ nano-crystal structure films deposition, as shown in Fig. 1. The NBAS system is based on the conventional RF magnetron sputtering and it has the electron cyclotron resonance (ECR) plasma source and metal reflector. $Ar^+$ ion in the ECR plasma can be accelerated into the plasma sheath between the plasma and metal reflector, which are then neutralized mainly by Auger neutralization. The neutral beam energy is controlled by the metal reflector bias. The controllable neutral beam energy can continuously change crystalline structures from an amorphous phase to nanocrystal phase of various grain sizes. The $Al_2O_3$ films can be high film density by controllable Auger neutral beam energy. we developed $Al_2O_3$ high dense barrier layer using NBAS process. We can verified that NBAS process effect can lead to formation of high density nano-crystal structure barrier layer. As a result, Fig. 2. shows that the NBAS processed $Al_2O_3$ high dense barrier layer shows excellent WVTR property as a under $2{\times}10^{-5}g/m^2day$ in the single barrier layer of 100nm thickness. Therefore, the NBAS processed $Al_2O_3$ high dense barrier layer is very suitable in the high efficiency OLED application.

• Journal of Preventive Medicine and Public Health
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• v.7 no.1
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• pp.131-138
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• 1974

The author has conducted survey on the status of physical growth and morbidity of the children for christian children's fund programme, as a means of collecting basic data for the anticipated establishment of a health planning. A total 345 children aged 9 to 16 underwent C.C.F. programme while as a control, a total of 480 children of same ages from the middle-class school children in Jeonju area was also studied. As results of survey conducted for a period of one month (form July 1 to 31, 1974) on a total 429 children in 347 households living in Jeonju area. I. Socio-economic background 1. By educational status of the children, 39.9 per cent of the total children was attending at primary school, 33.8 per cent in middle school and 15.6 per cent in high school. 2. The greatest proportion or 28.8 per cent of the household head were engaged in labor, 17.9 per cent in peddler and 13.2 per cent in retail. 3. As for the living standard of the households, low class constitued 90.1 per cent, middle and high classes only 9.9 per cent. 4. 39.5 per cent of the households had their own house, 39.1 per cent lived in rent deposit house or rooms and 14.6 per cent in monthly rented house and rooms. II. Physical growth and nutritional status 1. The growth of children for C.C.F. programme in terms of height was found to be slightly smaller than the school children. The ages frm 9 to 16 corespond to the 'secondary growth and replenishment period and this period was regarded to be the one most affected by environmental and nutritional factors of all the other periods of growth and developmet. 2. The body weight of the children for C.C.F. presented a quite different pattern from that of the school children. The above findings appeared thin-and-long stature from the famillies with higher living standard while those from the household with low standard of living had a short-and-plump one. 3. According to the values of Rohrer's index, the children of C.C.F carried a higher degree of 'replenishment' than the children in Jeonju area and adolesecence comes later for the girls under C.C.F. programme. III. Morbidity 1. The monthly prevalence rate was 110.0 per thousand persons for the children under C.C.F. programme. 2. The total number of case was classified by timing of the incidence as follws. 40.0 per cent was constituted by diseases carried over from tile previous month and 60.0 per cent by new incidences. 3. The diseases were broken down by W.H.O. disease classification into the greatest proportion or 39.1 per thousand person constituted by disease of the digestive system.

• Journal of the Korean earth science society
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• v.25 no.6
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• pp.484-494
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• 2004

The Soowang Au-Ag deposits occur as quartz veins which filled fissures in middle Cretaceous porphyritic granite an/or gneiss of the Precambrian Sobaegsan gneiss complex. The paragenetic studies suggest that vein filling can be divided into four identifiable stages (I to IV). Stage I is the main sulfide stage, characterized by the deposition of base-metal sulfide and minor electrum. Stage II is the electrum stage, whereas stage III represents a period of the deposition of silver-bearing sulfosalts and minor electrum. Stage IV is the post ore stage. Mineralogical and fluid inclusion evidences suggest that mineralization of the Soowang deposits were deposited by the cooling of the fluids from initial high temperatures 300$^{\circ}C$ to later low temperatures 150$^{\circ}C$. The salinity of the fluids were moderate, ranging from 10.4wt.% equivalent NaCl in sphalerite to 3.1wt.% equivalent NaCl in barite. The gold-silver mineralization of the Soowang mine occurred at temperatures between 140 and 250$^{\circ}C$ from fluids with log $fs_2$ from -12 to -18 atm. A consideration of the pressure regime during ore deposition, based on the fluid inclusion evidence of boiling, suggests lithostatic pressure of less than 210 bars. This pressure condition indicates that vein system of the Soowang deposit formed at depth around 800 m below the surface at the time of gold-silver mineralization.

• Journal of Physiology & Pathology in Korean Medicine
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• v.17 no.6
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• pp.1453-1462
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• 2003

In order to study the effect of oral administration of Mawhangyounpye-tang against to asthma, astham was induced to allergy-sensitive Balb/c mouse with ovalbumin using method of Hatfield et al (1997). The changes of diameter lumen of upper portion of the trachea, lung weight, gross appearance of lung, histological profiles of lung and trachea, numbers of cellular compartments in the bronchoalveolar lavage fluid (BALF), numbers and morphology of the mast cells in the trachea, numbers of mucus-secretory cell in the broncus, morphology of the bronchus, ultramicroscopical appearance of surface of trachea and number of cilia and mucous-secretory cells by scanning electron microscope. Obtained results were as follows. 1. The diameters of trachea lumen were significantly decreased in asthma induced control groups and these decreasing were result from hypertrophy of mucous membrane. However, these phenomena were dramatically recovered in the Mawhangyounpye-tang dosing groups. 2. Lung weights and black spots, which were result from infiltration of inflammatory cells, were significantly increased in asthma induced control groups but these phenomena were dramatically recovered in the Mawhangyounpye-tang dosing groups. 3. Hypertrophy of mucous membrane of trachea and bronchus and !bronchioles in the lung, peritracheal, peribronchus and peribronchiolar inflammatory cell infiltration, and mucoid exudate deposit in the lumen were observed in asthma induced control groups but these phenomena were dramatically recovered in the Mawhangyounpye-tang dosing groups. 4. Cellular compartments including neutrophil and eosinophil were dramatically increased in the BALF of asthma induced control groups but these phenomena were dramatically recovered in the Mawhangyounpye-tang dosing groups. 5. Mast cell degranulation and decreasing of the numbers of mast cells were detected in the trachea of asthma induced control groups. However, these phenomena were dramatically recovered in the Mawhangyounpye-tang dosing groups. 6. Shed, decreasing of cilia cell and increasing of mucous-secretory cells in the surface of the trachea of asthma induced control groups but these phenomena were dramatically recovered in the Mawhangyounpye-tang dosing groups. In conclusion, it Is considered that Mawhangyounpye-tang has somewhat favorable effect on the asthma because the asthma specific series of abnormalities in respiratory system were decreased after oral administratin of Mawhangyounpye-tang in this study. In future, it is needed that the toxicological and dosagespecific study of Mawhangyounpye-tang to use against asthma with safe.

• The Journal of the Korea Contents Association
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• v.14 no.8
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• pp.250-256
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• 2014

This study was carried out in order to seek social support direction by allowing them to recognize necessity of preparing for their stably old age life and by inquiring into the preparation for old age life targeting dental hygienists who work at dental clinics. It sent questionnaire by post to dental hygienists of 1,560 dental clinics, which were sampled with a stratified sampling method, and then conducted a cross-sectional study based on self-administration. As a result of a problem of being worried in old age life, the ratio with the response as saying of being 'economy' was indicated to be the highest. The ratio of financial preparation for old age was shown to be high with 84.3%. Its method was the highest in 'fixed deposit and installment savings' with 62.6%. The satisfaction with financial preparation for old age stood at averagely 2.60, thereby having shown to be dissatisfied. It was shown to be low with 2.97 in the mean score of physical preparation for old age life, 3.59 in emotional preparation, and 2.56 in preparation for leisure. In conclusion, the satisfaction with financial preparation for old age life in our country's dental hygienists was low. Even the physical, emotional, and leisure-based preparations were shown to be low. Hence, it is considered to be likely needed to be planned preparation for old age life from the 30s. Also, for this, Korean Dental Hygienists Association needs to positively develop several kinds of programs such as education, policy and system for old age life following these people's retirement.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.3 no.3
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• pp.1-7
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• 1983

In spite of extensive knowledge of the surface chemistry and the transport mechanism in filtration systems, there is still insufficient understanding of the physical characteristics of suspensions and the system components. Because of this, no filtration mechanisms are mathematically generalized to the full extent. The purpose of this paper is to propose experimental equations for the filtration process. using the tracer study in filter layer. Some of results are as follows. (1) The Volume of the specific deposit (${\sigma}$) in filtration was directly measurable using the tracer study without interrupting the filtration. (2) It was also confirmed that the head loss in filtration was greatly in fluenced by the micro-air babbles. (3) The correction coefficient(f) was introduced into the Kozeny-Carman equation in order to apply it for the clogging filter media. The coefficient(f) was experimentally obtained. The total head loss of the filter media is given by next equation. $${\frac{h}{h_0}}={\frac{1}{L}}{\int}^{z=L}_{z=0}f({\sigma})g({\varepsilon}_0,{\sigma})dz$$ $$f=aexp(-b{\sigma})$$ The above equation was applicable without regard to the variation of the suspension concentration, the filter medium diameter, the filter depth, the filtration velocity, and the amount of aluminum in all continuous filtration experiments. (4) The total head loss was graphically generalized assuming mathematical filtration models I II (see fig. 7,8) (5) The total head loss was obtained from the filtration model in the field filtration conditions. (see fig. 9,10)