• Journal of Sensor Science and Technology
• /
• v.33 no.1
• /
• pp.24-29
• /
• 2024

Inkjet printing technology is used to mass-produce displays and electrochemical sensors by dropping tens of pico-liters or less of specific-purpose ink through nozzles, just as ink is sprayed and printed on paper. Unlike the deposition method for vaporizing material in a vacuum, inkjet printing technology can be used for processing even under general atmospheric pressure and has a cost advantage because the material is dissolved in a solvent and used in the form of ink. In addition, because it can only be printed on the desired part, masks are not required. However, a technical shortcoming is the difficulty for commercialization, such as uniformity for forming the thickness and coffee ring effect. As sizes of devices decrease, the need to print electrodes with precision, thinness, and uniformity increases. In this study, we improved the printing and processing conditions to form a homogeneous electrode using Ag ink (DGP-45LT-15C) and applied this for patterning to fabricate a heat sensor. Upon the application of voltage to the heat sensor, the model with an extended width exhibited superior heat performance. However, in terms of sheet resistance, the model yielded an equivalent value of 21.6 Ω/□ compared to the ITO.

• Journal of the Korean earth science society
• /
• v.33 no.3
• /
• pp.280-293
• /
• 2012

In order to clarify the characteristics of dispersion of volcanic tephra emitted from the Mt. Baegdu with various eruption environment, numerical analysis were performed using numerical models, Weather Research and Forecast (WRF) and FLEXPART. Synoptic conditions at 12 October 2010 was adopted because the volcanic ash of Mt. Baegdu can reach the Korean peninsula and its dispersion pattern was compared with different Volcanic Explosivity Index (VEI) and particle size. Predominant size of falling out ash flowing in the peninsular is smaller than 0.5 mm and the ash large than the size is difficult to get in the peninsular due to the its weak ability of truculent diffusion. the difference of ash distribution with various VEI scenarios is not so much but number density of ash in the air is dramatically changed. Volcanic ash tends to be deposited easily in eastern coastal area such as Gangneung and Busan, because of the inflow of ash from East Sea and barrier effect of the Taeback mountains along the east coast of the Korean Peninsula. Accumulated amount of ash deposition can be increased in short period in several urban areas.

• Journal of the Korean earth science society
• /
• v.32 no.4
• /
• pp.360-372
• /
• 2011

In order to clarify the advection and dispersion characteristics of volcanic tephra to be emitted from the Mt. Baekdu, several numerical experiments were carried out using three-dimensional atmospheric dynamic model, Weather and Research Forecast (WRF) and Laglangian particles dispersion model FLEXPART. Four different temporally averaged meteorological values including wind speed and direction were used, and their averaged intervals of meteorological values are 1 month, 10 days, and 3days, respectively. Real time simulation without temporal averaging is also established in this study. As averaging time of meteorological elements is longer, wind along the principle direction is stronger. On the other hands, the tangential direction wind tends to be clearer when the time become shorten. Similar tendency was shown in the distribution of volcanic tephra because the dispersion of particles floating in the atmosphere is strongly associated with wind pattern. Wind transporting the volcanic tephra is divided clearly into upper and lower region and almost ash arriving the Korean Peninsula is released under 2 km high above the ground. Since setting up the temporal averaging of meteorological values is one of the critical factors to determine the density of tephra in the air and their surface deposition, reasonable time for averaging meteorological values should be established before the numerical dispersion assessment of volcanic tephra.

• Korean Journal of Environmental Agriculture
• /
• v.28 no.1
• /
• pp.15-19
• /
• 2009

Ammonia in atmosphere has a negative effect on the natural ecosystems, such as soil acidification and eutrophication, by wet and dry deposition. Livestock manure, compost, and fertilizer applications to arable land have been recognised as a major source of atmospheric ammonia emissions. The objective of this study was to evaluate the efficiency of compost application techniques in reducing ammonia loss in upland soil. The reductions in ammonia emission were 70 and 15% for immediate rotary after application (IRA) and rotary at 3 day after application (RA-3d) in comparison with surface application (SA). Total ammonia emissions for 13 days, expressed as % ammonia-N applied with compost, were 42, 35.7, and 12.7% for SA, RA-3d, and IRA treatments, respectively. The ammonia emission rate fell rapidly 6 h after application and 61 % of total ammonia emission occurred within the first 24 h following surface application. The lime application along with compost significantly enhanced the total ammonia emission. Total ammonia emission for 22 days were 40.1, 31.4, and 27.7 kg/ha for immediate incorporation in soil after lime and compost application, lime incorporation in soil following 3 days after compost surface application, and compost incorporation in soil following 3 days after lime surface application, respectively. Therefore, lime and livestock manure compost application at the same time was not recommended for abatement of ammonia emission in upland soil.

• Korean Journal of Soil Science and Fertilizer
• /
• v.44 no.6
• /
• pp.1207-1213
• /
• 2011

This study was conducted to assess $N_2O$ emissions in agricultural soils of Korea. According to 1996 and 2006 IPCC (Intergovernmental Panel on Climate Change) methodology, $N_2O$ emission was calculated the sum of direct emission ($N_2O_{DIRECT}$) and indirect emission ($N_2O_{INDIRECT}$). To calculate $N_2O$ emissions, emission factor was used default of IPCC and activity data was used the food, agricultural, forestry and fisheries statistical yearbook of MIFAFF (Ministry for Food, Agriculture, Forestry and Fisheries). It was emitted 8,608 $N_2O$ Mg resulted from direct emission by application of chemical fertilizer and animal manure, input in n-fixation crops and input of crop residues and emissions converted $N_2O$ into $CO_2$ equivalent was 2,668 $CO_2$-eq Gg. Indirect emission as $N_2O_{(G)}$ (atmospheric deposition of $NH_3$ and $NO_X$) and $N_2O_{(L)}$ (leaching and runoffs) were 4,567 and 6,013 $N_2O$ Mg and emissions converted $N_2O$ into $CO_2$ equivalent were 1,416 and 1,864 $CO_2$-eq Gg, respectively. Total $N_2O$ emission in Korea agricultural soil in 2009 was 5,948 $CO_2$-eq Gg.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.7 no.2
• /
• pp.141-147
• /
• 2005

This study investigated air pollutant levels and physiological variation of Ginkgo biloba in Chuncheon. The results were as follows: The annual average concentrations of $SO_2,\;NO_2\;and\;PM10$ were 0.004ppm, 0.013 ppm and $66{\mu}g/m^3$, respectively. The volume weighted average concentrations of ionic components were $SO_4\;^{2-}\;3.584 mg/m^3,\;NO_3^-\; 2.803 mg/m^3,\;Cl^-\;1.485 mg/m^3\;and\;NH_4\;^+\;0.998 mgg/m^3$ in precipitation. The annual wet deposition amount of the major ions was shown to be $SO_4^{2-}\;3.865g/m^2/yr,\;NO_3^-\;2.924g/m^2/yr,\;Cl^-\;2.773g/m^2/yr\;and\; NH_4\;^+\;1.485 g/m^2/yr$ during this study period. The seasonal averaged pH in leaves were spring pH 5.9 0.5, summer pH 5.5 0.4 and fall pH 5.1 0.3. The seasonal average water soluble sulfur content in leaves were spring 0.012 0.004%, summer $0.012\;0.002\%\;and\;fall\;0.020\;0.007\%$. The seasonal average water soluble sulfur content in bark were spring $0.0071\;0.0003\%,\;summer\; 0.0066\;0.0004\%,\;fall\;0.0063\;0.0004\%\;and\;winter\;0.0071\;0.0003\%$.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.12 no.4
• /
• pp.315-327
• /
• 2007

This study investigated temporal and spatial variation of Pb and stable Pb isotopes accumulated in Ulleung Basin core sediments (4) using MC ICP/MS in order to identify the sources of anthropogenic Pb in the East/Japan Sea. Leached (1M HCl) Pb concentration and isotope ratios ($^{207}Pb/^{206}Pb\;and\;^{208}Pb/^{206}Pb$) were nearly constant during 300 yrs past than 1930, but increased up to twice in concentration and as much as 3.41% (1.70%) after 2000. On the other hand, residual Pb concentrations were nearly constant for past 400 yrs. The accumulation rates of anthropogenic Pb in the basin area were in the range of $3.1-3.5mg/m^2/yr$, which were similar levels to total atmospheric Pb deposition fluxes from 1990s to the present. In the slope area, more increase of anthropogenic Pb accumulation than the levels expected from mass accumulation rate could be found after the middle of 1990s. From the detailed evaluation for the temporal and spatial variation of accumulation rate and isotope ratios of anthropogenic Pb, we proposed probable sources and pathways of anthropogenic Pb. Pb emmision by coal burning from the China and Korea initiated the accumulation of anthropogenic Pb in the sediments of East/Japan Sea from 1930s. The accumulation of Pb increased by the addition of anti-nocking agents from both countries untill the beginning of 1990s, but from the middle of 1990s to the present, the phase-out of gasoline additives and the rapid increase of coal burning from the China maintained the atmospheric Pb levels in the Ulleung basin nearly similar to before. However, the local sources within this basin might take an important role in the rapid increase of anthropogenic Pb accumulation in slope areas from the middle of 1990s.

• Journal of Radiation Protection and Research
• /
• v.39 no.1
• /
• pp.38-45
• /
• 2014

This paper describes the results of assessment of radiological dose resulting from operation of the Daedeok nuclear facilities including the HANARO research reactor, which has been performed to assure whether or not to comply with the regulation standards of the radioactive effluents releases. Based on the meteorological data and the radiation source term, the maximum individual doses were evaluated from 2010 to 2012. The atmospheric dispersion and the deposition factors of gaseous effluents were calculated using the XOQDOQ computer code. ENDOS-G and ENDOS-L code systems were also used for maximum individual dose calculation from gaseous and liquid effluents, respectively. The results were compared with the regulation standards for the radioactive effluents presented by the Nuclear Safety and Security Commission (NSSC). The effective doses and the thyroid doses of the maximum individual were calculated at the maximum exposed point in the Daedeok site, and contributions of exposure pathways to the radiological doses resulting from gaseous and liquid radioactive effluents were evaluated at each facility of the Daedeok site. As a result, the maximum exposed age was analysed to be the child group, and the operation of HANARO research reactor had a major effect more than 90% on the individual doses. The main exposure pathways for gaseous radioactive effluent were from ingestion and inhalation. The effective doses and the thyroid doses were considerably influenced by tritium and iodine, respectively. The gaseous radioactive effluents contributed more than 90% on the total doses, whereas the contributions of the liquid radioactive effluents were relatively low. Consequently, the maximum individual dose due to radioactive effluents from the nuclear facilities within the Daedeok site were less than 3% of the regulation standard over 3 years; therefore, it can be concluded that radioactive effluents from the nuclear facilities were well managed, with the radiation-induced health detriment for residents around the site being negligible.

• Journal of Korean Society of Forest Science
• /
• v.88 no.4
• /
• pp.541-554
• /
• 1999

The objectives of this study were to examine the amount of nutrient input by throughfall and stemflow, and the nutrient dynamics by throughfall, stemflow and soil solution among Piuns koraiensis, Larix leptolepis and hardwood forests including oaks at Kwangju-Gun, Kyonggi-Do. A total amount of rainfall during the study period was 1410.1mm. Of the total rainfall, 85% was from throughfall at the L. leptolepis stand, 84.5% at the thinned P. koraiensis stand, 83.2% at the unthinned P. koraiensu stand and 81.2% at the hardwood stand, showing greater throughfall at the conifer stand than at the hardwood stand. Stemflow showed 2.7% of rainfall at the hardwood stand, 1.3% at the unthinned P. koraiensis stand, 1.2% at the thinned P. koraiensis stand and 0.8% at the L. leptolepis stand, showing greater stemflow at the hardwood stand than at the conifer stand. Ion concentration of stemflow was greater than those of rainfall and throughfall. The conifer stand showed higher ion concentration than the hardwood stand both for cation and anion. The ion concentrations of throughfall and stemflow were higher in the descending order : $NH{_4}^+$-N > $K^+$ > $K^+$ > $Na^+$ > $Mg^{2+}$ for cations and $SO{_4}^{2-}$ > $NO{_3}^-$-N > $Cl^-$-N for anions. After the precipitation passed through the canopy, $K^+$ increased most at the hardwood stand, whereas $NH{_4}^+$-N did most at the P. koraiensis and L. leptolepis stands. The ion concentration of soil solution was higher in the descending order : $Ca^{2+}$ > $Mg^{2+}$ > $Na^+$ for cations and $NO{_3}^-$-N > $Cl^-$ > $SO{_4}^{2-}$ for anions. $NH{_4}^+$-N and $K^+$ seemed to be supplied primarily from atmospheric deposition while $Ca^{2+}$, $Mg^{2+}$ and $Na^+$ from weathering.

• Particle and aerosol research
• /
• v.11 no.3
• /
• pp.63-75
• /
• 2015

Atmospheric environment in Korea is influenced by outside, especially China. The concentrations of air pollutants in China have showed decreasing trends since 2000. However, these concentration levels in China are still higher than other developed countries. The Chinese Government has tried several measures to control the air pollution. In this study, the details of the amendments and smog reduction strategies in China, especially for Beijing are reviewed and the strategies for Korean side to promote cooperation in Northeast Asia are suggested and discussed. The Chinese State Council amended the Environmental Protection Provisions and Clean Air Act and announced The Action Plan for Air Pollution Control (2013-2017), focusing on three key regions, Beijing-Tianjin-Hebei area (Jing-Jin-Ji), Yangtze River Delta (YRD) and Pearl River Delta (PRD). These policy actions and plan are mainly for the reducing coal usage and emissions from vehicles. It is suggested that, Korea should actively promote multi-national cooperation in the region to take an initiative role in environmental areas.