• Journal of Korean Society for Atmospheric Environment
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• 제17권6호
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• pp.475-485
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• 2001

The presence of airborne particles in the earth atmosphere expert important controls on the global climate because of their effects on the radiative balance. However, there are major uncertainties associated with the direct and indirect radiative effects of aerosols. In addition, their physicochemical properties cannot only the decline of air quality but also damage human health. Airborne particles were collected by two different commercial air samples, high volume sampler(for TSP) and low volume sampler(for P $M_{10}$ ) at the campus of Kunsan National University during February to September, 2000. In most cases, TSP and P $M_{10}$ were sampled once a week for the duration of 24 hours from 9:00 a.m. In addition samples were collected more intenisve, when the yellow dust was expected. Each sample was analyzed for pH and major ions concentration (C $l^{[-10]}$ , S $O_4$$^{2-}$, N $O_3$$^{[-10]}$ , N $a^{+}$, N $H_4$$^{+}$, $K^{+}$, $Mg^{2+}$, $Ca^{2+}$) by ion chromatography and atomic absorption spectrophotometry. Acidity (pH) of TSP and P $M_{10}$ ranged from 5.09 to 8.51 and from 6.22 to 7.54, respectively. The concentrations of airborne particles were found to satisfy both the short and long-term air quality standards during the sampling period. If the ratio of ionic concentrations originating from None sea salt(Nss) to sea salt(ss) in aerosol samples was concerned, it was found that the ionic concentrations from marine environment contributed dominantly in total mass concentration in the airborne particles. When seasonal trends were examined, the TSP concentrations in spring were higher than those of other seasons. It may result form frequent occurrences of yellow dust and during the spring season. The concentration ratio of P $M_{10}$ to TSP ranged from 0.78 to 1 during the sampling period. pH in the airborne particle was highest during spring, but the other seasons maintained almost same level. These results suggest that alkaline species in yellow dust can directly neutralize aerosol acidity. During spring season, yellow dust could be a positive factor that can defer the acidification of surface soil and water by neutralizing acidic aerosols in the atmosphere.osphere.

• Asian-Australasian Journal of Animal Sciences
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• 제21권10호
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• pp.1416-1424
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• 2008

The objective of this research was to study the production and quality of forage at three different times of the year (April, June and July) of six winter cereals in the southern plateau of the Iberian Peninsula. The cereals studied were Triticale (xTriticosecale wittm) cv. "Tritano", Oat (Avena sativa L.) cv. "Prevision" and cv. "Saia; Rye (Secale cereale L.) cv. "Giganton", Barley (Hordeum vulgare L.) cv. "Cameo" and cv. "Albacete". The study was carried out in three different locations and over three successive years of harvesting. The three variables considered were location, year and cereal. The % dry matter (DM), % crude protein (CP), % acid detergent fiber (ADF), % neutral detergent fiber (NDF) and % ash content were determined for the three sampling periods and the quality was calculated in milk forage units (MFU/kg DM), the production in kg DM/ha, MFU/ha and kg CP/ha. In all three sampling periods the quality of the cereals was significantly influenced only by the year and by species. However, for production of dry matter (kg DM/ha), milk forage units (MFU/ha) and gross protein (kg CP/ha) all three variables were of significant influence as were their interactions. In the April sampling, the species which showed a significantly higher production ($p{\leq}0.05$) was rye (1,693 kg DM/ha), which, along with its forage quality (16.56% CP, 0.886 MFU/kg DM) meant that the same occurred in MFU/ha and kg CP/ha. Significant differences between species were also found for the June sampling. The most productive cereal was again rye with 2,656 kg DM/ha, although its sharp fall in forage quality meant that barley cv Albacete (2,513 kg DM/ha) returned the highest production in forage units (1,934 vs. 1,951 MFU/ha) and barley cv. Cameo (2,413 kg DM/ha) in gross protein production (242 vs. 264 kg CP/ha). The significantly highest cereal production for July was barley cv. Albacete (4,923 kg DM/ha, 9.11% CP 0.722 MFU/kg DM). As a consequence of the results, we conclude that from the viewpoint of nutritional quality and production, rye is the most suitable for use in early spring in whatever year and location. However, barley cv. "Albacete" is the most appropriate for utilisation in later spring or early summer.

• Journal of Korean Society for Atmospheric Environment
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• 제15권4호
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• pp.393-402
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• 1999

Precipitation samples were collected by the wet-only sampling method in Iksan in the northwest of Chonbuk from March 1995 to February 1997. These samples were analyzed for the concentration of ion components, in addition to pH and electrical conductivity. The annual mean pH of precipitation was 4.8 and the seasonal trend of pH was shown to be low in Fall and Winter(4.5), middle-ranged in Spring(4.7) and high in Summer(5.0). The frequency of pH below 5.6 was about 71%. The seasonal pattern of pH frequency was found to be different in each season. In the case of the pH less than 5.0, the frequency was higher in Spring, Fall and Winter than in Summer, especially higher in Fall than in other seasons. The concentrations of analysed ions showed a pronounced seasonal pattern. However, major ion species for all seasons were $NH^+_4,;Ca^{2+};and;Na^+$ among cations and $SO^{2-}_4,;Cl^-;and;NO^-_3$ among anions. The major acidifying species appeared to be $nss-SO^{2-}_4;and;NO^-_3$, and the main bases responsible for the neutralization of precipitation acidity were $nss-Ca^{2+};and;NH^+_4$. The potential acidity of precipitation, pAi, was found to be between 3.0 and 5.0 for total samples, while the measured pH was approximately between 3.9 and 7.8. The seasonal trend of pAi showed a decreasing order: Summer (4.3), Winter(4.0), Spring and Fall(3.8). During the Fall, both pAi and pH were especially very low, which indicated that during this period the potential acidity of precipitation was high but the neutralizing capacity was low. For Spring, pAi was very low but pH was slightly high. This was likely due to the large amount of $CaCO_3$ in the soil particles transported over a long range from the Chinese continent that were incorporated into the precipitation, and then neutralized the acidifying species with its high concentraton.

• Journal of Ginseng Research
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• 제28권4호
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• pp.165-172
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• 2004

Ginseng is traditionally cultivated worldwide in cold continental climates. It is now also being cultivated in maritime environments such as New Zealandis. This paper reports a number of growth and quality parameters for plants grown under those conditions over two growing seasons and the intervening winter dormant period. While shoot biomass peaked mid-summer, in contrast, root biomass peaked late autumn/early winter. Starch, sucrose, fructose, glucose and inositol were detected in the roots. Starch concentrations were highest in early autumn (mean 470 mg $g^{-1}$ dry weight) and lowest in mid spring (218 mg $g^{-1}$ dry weight). Sucrose concentrations were low during early summer until late autumn but increased rapidly with the onset of winter and peaked during mid spring (168 mg $g^{-1}$ dry weight). Fructose and glucose concentrations were similar and peaked in late spring (5.3 and 6.2 mg $g^{-1}$ dry weight). Inositol concentrations peaked in mid summer (1.7 mg $g^{-1}$ dry weight). Starch/sugar ratios were high during summer and autumn and low during winter and spring. Ginsenoside concentrations and profiles showed that the six major ginsenosides, Rgl, Re, Rb1, Rc, Rb2 and Rd, were present, but Rf was absent. Concentrations did not vary with sampling date. The most abundant ginsenosides were Re (15.9 to 17.5 mg $g^{-1}$ dry weight) and Rb1 (10.7 to 18.1 mg $g^{-1}$ dry weight). Combined, they accounted for < $75{\%}$ of total ginsenoside concentrations. Limited taste tests indicated that highest root quality occurred during late autumn, after the shoots had senesced. However, quality could not be related to plant chemistry.

• Journal of Korean Society of Forest Science
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• 제99권5호
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• pp.698-705
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• 2010

The concentration of monoterpenes (12 species) was measured from spring to fall in 2008 in ambient air at six different forests located in the southern parts of Korea. Sampling - using a Solid Adsorption Tube - was conducted at 2-hour-interval a day (24 hours) of each season. The highest annual average concentration of total monoterpene was 0.715 ppbv, which occurred at Mt. Baega. ${\alpha}$-Pinene, sabinene and ${\beta}$-pinene were the most abundant compounds throughout the sampling periods and areas. The concentrations of monoterpene were higher in spring than in any other seasons. The compositions and concentrations of monoterpene displayed a distinct pattern by area. Most of monoterpenes had diurnal variations with higher concentrations during the daytime, and lower during the nighttime. This may be due to the fact that the amount of monoterpenes emitted increases at elevated ambient temperatures and increased sunlight intensity. The results of this study showed that each area had distinct monoterpene compositions, which depended on the tree species, topography and local climate at each area.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제14권11호
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• pp.5338-5343
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• 2013

In a haptic system, a virtual wall is modeled as a virtual spring. The larger the stiffness of the virtual spring is, the more improved the reality of the virtual wall is, but the more unstable the haptic system becomes. This paper shows how to increase the stiffness of the virtual spring while the stability of the haptic system is guaranteed and shows the effects of a mass (Md) and a damper (Bd) of a haptic device on the stability when first-order hold method is applied and a virtual wall is modeled as a virtual spring (Kw). The simulation results show the boundary of the virtual spring is proportional to the square root of the mass (Md) and the damper (Bd) while maintaining the stability. The relation among the virtual spring (Kw), the mass (Md) and the damper (Bd) of the haptic device, and sampling time (T) is inferred as $K_w{\leq}{1.611M_d}^{0.50}{B_d}^{0.50}T^{-1.51}$, by using the simulation results. The maximum available stiffness of the virtual spring in first-order hold method is larger than in zero-order hold method. So the reality of the virtual wall can be improved.

• Journal of Environmental Health Sciences
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• 제39권1호
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• pp.56-70
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• 2013

Objectives: This paper aims to investigate the seasonal deposition characteristics of water-soluble ion species by comparing the deposition amount of two samples taken according to different sampling methods of deposition for ambient aerosol such as gases and particulate matters. Methods: Deposition samples were collected using two deposition gauges in the downtown area of Iksan City over approximately two weeks of each season in 2004. The type of deposition gauges consisted of two different sampling methods known as dry gauge and a wet gauge. The dry gauge was empty and used a dry PE bottle with an inlet diameter of 9.6 cm. Before the beginning of each deposition sampling, a volume of 30-50 ml distilled ionized water was added to the wet gauge to wet the bottom during the sampling period. Deposition samples were measured twice per day and analyzed for inorganic water-soluble ion species using ion chromatography. Results: The daily deposition amounts of all measured ions in the dry gauge and the wet gauge showed a significant increase when precipitation occurred, having no difference of deposition amount between in the wet gauge and in the dry gauge. By excluding two samples from rainy days during the sampling period, the mean daily deposition of all ions in dry gauge and wet gauge were $6.58mg/m^2/day$ and $18.16mg/m^2/day$, respectively. The mean deposition amounts of each ion species were higher in the wet gauge than in the dry gauge because of the surface difference of the sampling gauge, especially for $NH_4{^+}$ and ${SO_4}^{2-}$. The mean deposition amounts of $NH_4{^+}$ and ${SO_4}^{2-}$ in the wet gauge were found to be about 15.4 times and 5.2 times higher than that in dry gauge, with a pronounced difference between spring and summer, while the remaining ion species were 1.1-2.0 times higher in the wet gauge than in the dry gauge. Dominant species in the dry gauge were $Ca^{2+}$ and $NO_3{^-}$, accounting for 36.4% and 18.1% of the total ion deposition, whereas those in the wet gauge were $NH_4{^+}$ and ${SO_4}^{2-}$, accounting for 32.5% and 25.0% of the total ion deposition, respectively. Conclusion: The seasonal differences in deposition amounts of water-soluble ion species in ambient aerosol depending on the two types of different sampling methods were identified. This suggests that the removal of ambient aerosol is strongly influenced by the weather conditions of each season as well as the condition of earth's surface, such as dry ground and water.

• Journal of Korean Society for Atmospheric Environment
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• 제19권E1호
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• pp.11-20
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• 2003

To characterize airborne particulate carbon and its temporal variation in the heavily industrialized metropolitan city, Seoul in South Korea, aerosol sampling was performed from 1986 to 1996. Correlation coefficients of elemental carbon (EC) and organic carbon (OC) with mass concentration of fine particles ($\underline{\leq}$2.1 ${\mu}m$) are 0.73 and 0.51, respectively. EC concentrations of the fine particle mode are 10.1, 5.9, 4.5, and 7.4 ${\mu}g\;m^{-3}$ in winter, spring, summer, and autumn, respectively. On the other hand, OC concentration shows maximum value in winter and followed by autumn, summer, and spring. A seasonal peak in the ratio of OC to EC in fine particles was observed during the summer photochemical season from June to August. Concentrations of EC and OC in Asian dust storm events are generally higher than in non- Asian dust storm events except in 1990. The difference of EC concentrations between Asian dust storm periods and non-Asian dust storm periods are much larger than those of OC concentrations. There are slight increases of EC concentration between 1987 and 1990 and a gradual decrease between 1990 and 1996.

• Journal of Environmental Health Sciences
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• 제22권2호
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• pp.124-129
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• 1996

In order to investigate the deposition chara.cteristics of water-soluble ionic components in dustfall in Kwangju city, dustfall samples were collected by deposit jar for one year from December 1992 to November 1993. The depositjon amount of dustfall and water-soluble ionic components ($SO_4^{2-}, NO_3^-, Cl^-, NH_4^+, Na^+, Ca^{2+}, Mg^{2+}, K^+$) were measured. The total deposition amount of dustfall was 10.0 ton/$km^2$/month and showed seasonal trend of Summer and Spring > Fall and Winter. The total deposition amounts of water-soluble components showed 2.41 ton/$km^2$/month and seasonal trend of Summer > Fall > Spring > Winter. Deposition amount of $SO_4^{2-}$ was 0.99 ton/$km^2$/month which makes up 41% of water-soluble components. The deposition amounts of dustfall and watersoluble components according to the sampling points were approximately similar to each other. From this result, it can be estimated that the deposition amounts of dustfall and water-soluble components in dustfall were more influenced by the seasonal variation than the regional emission characteristics of pollution source. The content of each ionic component to the deposition amount of water-soluble components showed in order of $SO_4^{2-} > Cl^- > NH_4^+ > Na^+ > Ca^{2+} = K^+ > NO_3^- > Mg^{2+}$ respectively.

• Journal of Korean Society for Atmospheric Environment
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• 제18권4호
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• pp.297-303
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• 2002

Fine particles (d$_{p}$ < 2.5 $\mu$m) were measured using an annular denuder system (ADS) in Chongju. The data set was collected on fifty-eight different days with a 24-hr sampling period from October 27, 1995 through August 25, 1996. Particulate nitrate in the ADS was also measured on teflon and nylon filters in series behind denuders to collect HNO$_3$, HNO$_2$, SO$_2$and NH$_3$. From this study. the mean concentration of particulate nitrate of PM$_{2.5}$ in the ADS were seen with the following order: winter (5.05) ＞fall (4.36) ＞spring (3.92) > summer (1.10 $\mu\textrm{g}$/㎥). Nitrate losses, which calculated from the ratio of nylon filter nitrate to the sum of teflon and nylon filter nitrates, varied in the following manner summer (72.2%) > spring (42.6%) > fall (23.5%)> winter (0.4%). Especially, gaseous nitric acid was dominant at temperature higher than 8$^{\circ}C$ while particulate nitrate was major species in total nitrate below that temperature. This indicates the particulate nitrate loss is strongly correlated rather with ambient temperature.e.e.