• Journal of Korean Society for Atmospheric Environment
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• v.23 no.3
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• pp.322-331
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• 2007

In this study, we have analyzed $PM_{10}$ concentration measured at Incheon Regional Air Monitoring Network (10 stations) and meteorological data at Incheon Weather Station to investigate factors (i.e. wind direction, wind speed, relative humidity, major meteorological phenomenon, and sea-land breezes existence) influencing $PM_{10}$ concentration in Incheon during 2005. Statistical differences among meteorological factors were assessed by Kruskal-Wallis test or Mann-Whitney U test. The main conditions causing high $PM_{10}$ concentration are summarized below; 1. When westerly wind prevailed (however, $PM_{10}$ decreased when winds were blowing from the east or north). 2. When the winds were calm, owing to accumulation of nearby emissions under stagnant conditions, or when the wind speed is in excess of 6 m/s, which shows the effect of fugitive dust produced by wind erosion. 3. Under the condition of high relative humidity and poor diffusion based on meteorological phenomenon such as fog, mist, and haze. 4. When the Sea-Land breezes existed, which occurred 70 days in Incheon during 2005 and contributed significantly to high $PM_{10}$ concentration in the coastal urban area. In conclusion, we have found that the meteorological factors have influence on $PM_{10}$ concentration in Incheon.

• Particle and aerosol research
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• v.5 no.2
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• pp.53-62
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• 2009

In this study, the continuous monitoring of the concentration of PM-10 atmospheric particulate matter using beta ray attenuation method was compared with gravimetric method from September, 2006 to August, 2007. On the effects of the PM-10 concentration and mass difference by relative humidity and precipitation were considered. The result showed that the measurement error between beta ray method and gravimetric method are within -3~6% in average, which means PM-10 concentration data with beta ray method are relatively comparable. The current study also shows that the high PM-10 concentration events are mainly due to haze, Asian dust, and high relative humidity and the PM-10 mass concentration is closely related with relative humidity and precipitation events. Based on daily mean data, the PM-10 increases as relative humidity increases up to 70~80%, then decreases over 80% due to the precipitation. However, the distinct measurement discrepancy was not shown between beta ray method and gravimetric method based on current results. Consequently, this study shows that the collocated measurement in different instrument is essential in order to quantify the accuracy of PM-10. Furthermore, the more comprehensive and spatially distributed comparison is needed and this is remained for future study.

• Journal of Korean Society for Atmospheric Environment
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• v.10 no.3
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• pp.203-208
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• 1994

The trend of visibility variation of Seoul during 1980-1993 is analyzed. Annual average visibility has been decreased during the 1980s except 1988 and 1989 but not decreasing during the early 1990s. Also, the number of days with haze during 1983-1993 did not increase. Mixing height is deemed to be a dominant factor determining visibility. During the period, the difference between the average visibility at 6 p.m and 9 a.m decreased with the average visual range at 9 a.m slightly increased. Thus there is possibility that the effect of Photochemcial reactions becomes noticeable. The number of vehicles and the concentration of criteria air pollutants on the trend of visibility variation of Seoul would not be directly related to the variation of visibility.

• Journal of Environmental Science International
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• v.25 no.1
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• pp.107-125
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• 2016

Long-term variations of $PM_{10}$ and the characteristics of local meteorology related to its concentration changes were analyzed at 4 air quality sites (Ido-dong, Yeon-dong, Donghong-dong, and Gosan) in Jeju during two different periods, such as PI (2001-2006) and PII (2007-2013), over a 13-year period. Overall, the long-term trend of $PM_{10}$ was very slightly downward during the whole study period, while the high $PM_{10}$ concentrations in PII were observed more frequently than those in PI. The concentration variations of $PM_{10}$ during the study period was clarified in correlation between $PM_{10}$ and meteorological variables, e.g. the low (high) $PM_{10}$ concentration with large (small) precipitation or high (low) radiation and in part high $PM_{10}$ concentrations (especially, Donghong-dong and Gosan) with strong wind speed and the westerly/northwesterly winds. This was likely to be caused by the transport effect (from the polluted regions of China) rather than the contribution of local emission sources. The $PM_{10}$ concentrations in "Asian dust" and "Haze" weather types were higher, whereas those in "Precipitation", "Fog", and "Thunder and Lighting" weather types were lower. The contribution of long-range transport to the observed $PM_{10}$ levels in the urban center (Ido-dong, Yeon-dong, and Donghong-dong), if estimated by comparison to the data of the background site (Gosan), was found to explain about 80% (on average) of its input.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.345.2-345.2
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• 2016

Alumina (Al2O3) doped zinc oxide (ZnO) films (AZO) have been prepared from 2 wt.% Al2O3 doped ZnO target by DC magnetron sputtering at a 2 mTorr (0.27 Pa) chamber pressure in (15 sccm) argon ambient. We obtained films of various opto-electronic properties by variation of target angle from 32.5o to 72.5o. At lower target angle deposited films show higher values in optical gap, mobility of charge carrier, carrier concentration, crystallite grain size, transmission range of wavelength, which are favorable characteristics of AZO as a transparent conducting oxide (TCO). At higher target angle the sheet resistance, work function, surface roughness for the AZO films increases. Measured haze ratio of the films changed lower to higher and size of characteristic surface structure of as deposited film ranges from ~40 nm to ~300 nm. By a combination of low and high target angle we obtained a textured TCO film with high conductivity.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.309-309
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• 2010

We have investigated the effect of $H_2$ plasma treatment on the BZO (ZnO:B, Boron doped ZnO) thin films. The BZO thin films are prepared by LP-MOCVD (Low Pressure Metal Organic Chemical Vapor Deposition) technique and the samples of BZO thin film are performed with $H_2$ plasma treatment by plasma treatment system with 13.56 MHz as RIE (Reactive Ion Etching) type. After exposing $H_2$ plasma treatment, measurement of transmittance, reflectance and haze spectra in 300~1100 nm, electrical properties as resistivity, mobility and carrier concentration and work function was analysed. Regarding the results of the $H_2$ plasma treatment on the BZO thin films are application to the TCO for solar cells, such as the a-Si thin films solar cell.

• Korean Journal of Materials Research
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• v.19 no.5
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• pp.259-264
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• 2009

In this study we investigated the effect of the multi-step texturing process on the electrical and optical properties of hydrogenated Al-doped zinc oxide (HAZO) thin films deposited by rf magnetron sputtering. AZO films on glass were prepared by changing the $H_2/(Ar+H_2)$ ratio at a low temperature of $150^{\circ}C$. The prepared HAZO films showed lower resistivity and higher carrier concentration and mobility than those of non-hydrogenated AZO films. After deposition, the surface of the HAZO films was multi-step textured in diluted HCl (0.5%) for the investigation of the change in the optical properties and the surface morphology due to etching. As a result, the HAZO film fabricated under the type III condition showed excellent optical properties with a haze value of 52.3%.

• Journal of Korean Society for Atmospheric Environment
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• v.26 no.4
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• pp.392-402
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• 2010

Black carbon (BC) concentrations were measured with an aethalometer (AE-16, 880 nm) at time interval of 5-min at an urban site of Gwangju over a year 2008. 24-hr filter-based integrated measurements of $PM_{2.5}$ particles were also made at the same site during the winter and summer intensive periods to test any optical loading bias in the raw BC data measured by aethalometer. BC concentration was higher in winter than in summer, possibly due to increase in emissions from energy consumption and poor dispersion with reduction of boundary layer in winter. Also temporal cycles of BC indicate that short-term transient spikes were common, occurring primarily during the rush-hour periods. A similar feature was also observed in diurnal concentration cycle of CO, mainly emitted from motor vehicles. When both low wind speed and weather patterns such as mist, haze and etc were combined, high BC concentrations frequently occurred. The amount of optical loading effect described by the "k" factor showed the seasonal variation, ranging from 0.0003 to 0.0036. This implies that optical loading effect is not seen at all times. From the comparison between the filter-based elemental carbon (EC) and aethalometer BC data, it was found that the loading compensated BC values were more reasonable than the raw BC ones reported from the aethalometer.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.272-277
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• 2019

In this paper, a manufacturing method of an anti-glare cover glass on LCD for outdoor use is proposed. The main specification of cover glass is hardness and anti-glare. Hardness is achieved by using the tempered glass, and anti-glare(AG) film is laminated to meet anti-glare specification no the tempered glass. However, the AG film is difficult to maintain the AG performance continuously because the abrasion resistance of the PET film itself is as weak as about 3H. Therefore, a novel production procedure using screen printing method is proposed. The proposed coating is implemented by applying $ZnO-B_2O_3-SiO_2$ powder on glass surface and the glass is made with enhanced hardness through tempering process. In order to apply the ZBS powder uniformly on the glass surface, a screen printing process is used. The main parameters to be considered in screen printing are the oil concentration and mesh opening size. Because the amount of ZBS powder applied to the printing process is controlled by these two parameters, the correlativity is confirmed through the experiments. In order to evaluate the performance of the proposed method, the haze, surface roughness and transmittance are selected as the performance index and are compared with the AG film. As a result of comparison, it is verified that the transmittance of the proposed tempered glass is 83.1%, which is slightly lower than 89.5% of AG film, but the hardness is more than double to 7H.

• Analytical Science and Technology
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• v.27 no.1
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• pp.1-10
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• 2014

The $PM_{10}$ and $PM_{2.5}$ samples were collected at Gosan Site of Jeju Island, and analyzed, in order to investigate the size distribution and pollution characteristics of their components. $NH{_4}{^+}$, nss-$SO{_4}^{2-}$, $K^+$, and $CH_3COO^-$ were mostly existed in fine particles. Meanwhile, $NO{_3}{^-}$ was distributed in both fine and coarse particles, and $Na^+$, $Cl^-$, $Mg^{2+}$, nss-$Ca^{2+}$ were rich in coarse particle mode. The concentrations of nss-$Ca^{2+}$ and $NO{_3}{^-}$ were increased 36.7 and 3.2 times in coarse particles, and 15.0 and 3.1 times in fine particles during the Asian Dust periods. Especially, the concentrations of crustal elemental species such as Al, Fe, Ca, K, Mg, Ti, Mn, Sr, Ba were highly increased for those periods. In the haze events, the concentrations of secondary air pollutants were increased 1.3~2.6 and 1.5~4.2 times in coarse and fine particles, respectively. Moreover, the remarkable increase of $NO{_3}{^-}$ concentration was also observed in fine particle mode. The factor analysis showed that the composition of coarse particles was influenced mainly by marine sources, followed by soil and anthropogenic sources. On the other hand, the fine particles were influenced by anthropogenic sources, followed by marine and soil sources.