• Journal of Korea Foresty Energy
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• v.21 no.2
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• pp.25-33
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• 2002

One of the critical problems to preserve books and documents in libraries and archives is the deterioration. Some of previous results showed that the major cause of paper deterioration was the acid-catalyzed hydrolysis of the cellulose in paper fibres and aging rate of acidic paper was faster than that of alkaline paper. Therefore, It is necessary to remove the acid in the paper for reducing the rate of paper deterioration. It has been reported to extend the useful life of acidic paper by three to five times. Recently, It has been recognized the need for an effective method of deacidifying large quantities of books and document. However, in the previous many reports little attention was paid to the effect of paper additives. In this paper, We carried out experiment about the effect of additives on paper aging and the effect of deacidification by the gaseous ethanolamines (monoehtanolamine, diethanolamine, triehtanolamine). In result, it was found that the strength of aging was in the order of the alum＋rosin＞alum ＞AKD＞ control and the rate of deacidification was in the order of the monoethanolamine＞diethanolamine＞triethanolamine. The treatment with the gaseous ethanolamines caused decreasing of brightness and dropping of fold endurances. However, deacidification by combination treatment of the various gaseous ehtnaolamines prevented from decreasing of brightness and dropping of folding endurances.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.2
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• pp.157-166
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• 1995

The fate and use efficiency of applied nitrogen were evaluated in a pot experiment with different fertilizers and water management practices during 30days after fertilizer application. N-P-K compound fertilizers, 13-10-1l(F-l) for upland Crop use and 15-10-10(F-3) for rice Crop use, and mixed fertilizer, 21-17-17(F-2) for basal dressing in rice were used. Fertilizers corresponding to 1.8g N were mixed thoroughly with the whole volume of sandy loam soil in a pot. The pots were flooded upto 3cm above soil surface for O(0dF), 10(10dF), 20(20dF), and 30(30dF) days after fertilizer application and all the treatments were flooded continuously from 30 days after fertilizer application. During the flooding period water percolation rate was adjusted to 2.5mm/day. Rice seedlings were transplanted 40 days after fertilizer application. The pH of infiltrated water increased with increasing duration of flooding. The pH of F-2 was higher than those of F-1 and F-3 between which there were no differences. The applied nitrogen remained 23% in F-1, 29% in F-2, and 29.1 % in F-3, and 45.0% in 0dF, 26.6% in 10dF, 24.8% in 20dF, and 20.3% in 30dF as inorganic nitrogen at 63 days after fertilizer application. Nitrogen losses by leaching amounted to 51.3%, 32.1% and 48.1% of applied nitrogen in F-1, F-2 and F-3, respectively. Nitrogen leaching losses increased with increasing duration of flood- ing, amounting to 25.7%, 29.8%, 32.7%, and 35.8% in 0dF, 10dF, 20dF and 30dF, respectively. Gaseous loss of applied nitrogen was greatest in F-2, followed by F-1 and F-3. Total loss of nitrogen due to gaseous volatilization and leaching was greatest in F -1, followed by F -2 and F-3, and were greater in the treatments with longer flooding after fertilizer application. Nitrogen recovery by rice shoot until 72 days after transplanting were 23.2%, 24.7% and 27.4% of applied nitrogen in F-1, F-2 and F-3, respectively and 34.1%, 25.5%, 21.1%, and 21.2% in 0dF, 10dF, 20dF and 30dF, respectively.

• Asian Journal of Atmospheric Environment
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• v.8 no.1
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• pp.35-47
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• 2014

The purpose of the study is to evaluate the pollution level (gaseous and particle phase) in the public facilities for the PAHs, non-regulated materials, forecast the risk level by the health risk assessment (HRA) and propose the guideline level. PAH assessments through sampling of particulate matter of diameter < 2.5 ${\mu}m$ ($PM_{2.5}$). The user and worker exposure scenario for the PAHs consists of 24-hour exposure scenario (WIES) assuming the worst case and the normal exposure scenario (MIES) based on the survey. This study investigated 20 PAH substances selected out of 32 substances known to be carcinogenic or potentially carcinogenic. The risk assessment applies major toxic equivalency factor (TEF) proposed from existing studies and estaimates individual Excess Cancer Risk (ECR). The study assesses the fine dusts ($PM_{2.5}$) and the exposure levels of the gaseous and particle PAH materials for 6 spots in each 8 facility, e.g. underground subway stations, child-care facilities, elderly care facilities, super market, indoor parking lot, terminal waiting room, internet caf$\acute{e}$ (PC-rooms), movie theater. For internet caf$\acute{e}$ (PC-rooms) in particular, that marks the highest $PM_{2.5}$ concentration and the average concentration of 10 spots (2 spots for each cafe) is 73.3 ${\mu}g/m^3$ (range: 6.8-185.2 ${\mu}g/m^3$). The high level of $PM_{2.5}$ seen in internet cafes was likely due to indoor smoking in most cases. For the gaseous PAHs, the detection frequency for 4-5 rings shows high and the elements with 6 rings shows low frequency. For the particle PAHs, the detection frequency for 2-3 rings shows low and the elements with 6 rings show high frequency. As a result, it is investigated that the most important PAHs are the naphthalene, acenaphthene and phenanthrene from the study of Kim et al. (2013) and this annual study. The health risk assessment demonstrates that each facility shows the level of $10^{-6}-10^{-4}$. Considering standards and local source of pollution levels, it is judged that the management standard of the benzo (a)pyrene, one of the PAHs, shall be managed with the range of 0.5-1.2 $ng/m^3$. Smoking and ventilation were considered as the most important PAHs exposure associated with public facility $PM_{2.5}$. This study only estimated for inhalation health risk of PAHs and focused on the associated cancer risk, while multiple measurements would be necessary for public health and policy.

• 한국균학회소식:학술대회논문집
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• 2014.10a
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• pp.25-25
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• 2014

Three species of Fusarium, F. fujikuroi, F. verticillioides and F. proliferatum, are known to be associated with bakanae disease of rice [1, 2]. F. fujikuroi infects rice flowers and survive in endosperm and embryo of the seeds. Infected seed is an important source of primary inoculum of pathogens [3]. Seeds of rice (Oryza sativa cv. Boramchan) collected from bakanae-infected field were found to be 96% infected with Fusarium sp., 52% with F. fujikuroi, 42% with F. verticillioides, and 12% with F. proliferatum as determined by incubation method and species-specific PCR assays. F. fujikuroi was detected at lemma/palea, endosperm and embryo whereas F. verticillioides and F. proliferatum were recovered only from lemma/palea by means of component plating test. Seed disinfection methods have been developed to control bakanae disease and prochloraz has been most widely used for rice seeds. Two chemicals formulated with prochloraz (PC 1) and prochloraz + hexaconazole (PC 2) that inhibit biosynthesis of ergosterol strongly reduced the incidence of Fusarium spp. on selective media to 4.7% and 2.0%, respectively. Disease symptoms of rice seedlings in nursery soil were alleviated by chemical treatment; seedlings with elongated leaves or wide angle between leaf and stem were strikingly reduced from 15.6 to 3.2% (PC 1) and 0 (PC 2), stem rots were reduced from 56.9 to 26.2% (PC 1) and 32.1% (PC 2), and normal seedling increased from 0.4 to 13.3% (PC 2). Prochloraz has some disadvantages and risks such as the occurrence of tolerant pathogens [4] and effects on the sterol synthesis in animals and humans [5]. For these reasons, it is necessary to develop new disinfection method that do not induce fungal tolerance and are safe to humans and animals. Chlorine dioxide ($ClO_2$), that is less toxic, produces no harmful byproducts, and has high oxidizing power, has been reported to be effective at disinfection of several phytopathogenic fungi including Colletotrichum spp. and Alternaria spp. [6]. Gaseous $ClO_2$ applied to rice seeds at a concentration of 20 ppm strongly suppressed mycelial growth of Fusarium fujikuroi, F. verticillioides and F. proliferatum. The incidence of Fusarium spp. in dry seed with 8.7% seed moisture content (SMC) tended to decrease as the concentration of $ClO_2$ increased from 20 to 40 ppm. Applying 40 ppm $ClO_2$ at 90% relative humidity, incidence was reduced to 5.3% and resulted in significant reduction of disease symptoms on MS media. In nursery soil, stem rot was reduced from 56.9 to 15.4% and the number of normal seedlings increased from 0.4 to 25.5%. With water-soaked seeds (33.1% SMC) holding moisture in the endosperm and embryo, the effectiveness of disinfection using $ClO_2$ increased, even when treated with only 20 ppm for four hours. This suggests that moisture was a key element for action of $ClO_2$. Removal of the palea and lemma from seeds significantly decreased the incidence of Fusarium spp. to 3.0%. Seed germination appeared to decrease slightly by water-soaking at $30^{\circ}C$ because of increased SMC and by physical damage of embryos from hulling. These results indicate that the use of gaseous $ClO_2$ was effective as a means to disinfect rice seeds infected with Fusarium spp. and that moisture around the pathogens in the seed was an important factor for the action of $ClO_2$. Further investigations should be conducted to ascertain the best conditions for complete disinfection of Fusarium spp. that infect deep site of rice seeds.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.2
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• pp.94-102
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• 2008

The physico-chemical properties of ten reclaimed saline soils in five soil series of west-south Korea were analyzed according to the years past after reclamation. The soil samples were collected at the same sites two times in 2000 and 2004. The physico-chemical properties in 2000 had been changed in 2004 as follows. Soil salinity was the highest in Podu and desalinization period was the shortest in Munpo and Yeompo. Seasonal ground water level were above 100 cm in all regions that were 30 years old reclaimed tidal land, which was the same results of normal paddy field. In the case of soil physical changes, bulk density increased in fine textured soil (Poseung and Podu) but decreased in coarse textured soil (Gwanghwal, Munpo, and Yeompo). Porosity decreased in fine textured soil(Poseung and Podu) but increased in coarse textured soil. These reason were as follows. Fine textured soil were increased in solid phase but decreased in liquid and gaseous phase. Coarse textured soil, Gwanghwal and Munpo except for Yempo, were increased in gaseous phase but decreased in solid and liquid phase. Yempo that have low water table level were increased in liquid phase but decreased in solid and gaseous phase. Soil hardness increased in 4 soil series except for Munpo. In the case of chemical property changes, although there were more or less difference, it showed decreasing tendencies. Soil pH, the content of organic matter, available phosphate, and available silicate of five soil series were decreased during the four years. The content of exchangeable cation also decreased except for magnesium.

• Applied Microscopy
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• v.45 no.4
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• pp.242-248
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• 2015

In this paper, three carbon sources, i.e., solid graphite, gaseous CH4 and liquid ethanol, and one solid silicon source were employed to synthesize SiC/C nanocomposite powders by arc-discharge plasma. The processing conditions such as the component ratios of raw materials, atmospheric gases, etc. were adjusted for controllable synthesis of the nanopowders. It is indicated that both of solid graphite and silicon can be co-evaporated and reacted to form nanophases of cubic ${\beta}$-SiC with ~50 nm in mean size and a little free graphite; the carbon atoms decomposed from gaseous $CH_4$ favor to combine with the evaporated silicon atoms to form the dominant SiC nanophase; liquid carbon source of ethanol can also be used to harvest the main ${\beta}$-SiC and minor 6H-SiC phases in the assembly of nanoparticles. The as-prepared SiC/C nanocomposite powders were further purified by a heat-treatment in air and their photocatalytic performances were then greatly improved.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.6
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• pp.648-653
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• 2006

As an alternative for the traditional materials packed in biofilters treating gaseous VOCs, a novel packing material has been developed and tested. In the packing material(named as Hydrogel Bead, HB), pollutant-degrading microorganisms were immobilized in hydrogel consisted of alginate, polyvinyl alcohol(PVA), and powdered activated carbon. A closed-bottle study showed that the HB rapidly removed gaseous styrene without the losses of adsorption and biodegradation capacity. Biofilter column experiments using the HBs also demonstrated that greater than 95% of removal efficiencies were found at an inlet styrene loading rate of $245g/m^3/hr$, which was higher biofilter performance than other elimination capacity reported earlier. Furthermore, when the inlet styrene concentration increased stepwise, the adsorption played an important role in overall styrene removals. The absorbed styrene was found to be biodegraded in the following low inlet loading condition. Consequently, the new HB material is able to successfully minimize the drawbacks of activated carbon(necessity of regeneration) and biological processes(low removal capacity at dynamic loading conditions), and maximize the overall performance of biofilter systems treating VOCs.

• Geophysics and Geophysical Exploration
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• v.9 no.1
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• pp.10-18
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• 2006

We measured the changes in P-wave velocity that occur when injecting $CO_2$ in gaseous, liquid, and supercritical phases into water-saturated anisotropic sandstones. P-wave velocities were measured in two cylindrical samples of Tako Sandstone, drilled along directions normal and parallel to the bedding plane, using a piezo-electric transducer array system. The velocity changes caused by $CO_2$ injection are typically -6% on average, with maximum values about -16% for the case of supercritical $CO_2$ injection. P-wave velocity tomograms obtained by the differential arrival-time method clearly show that $CO_2$ migration behaviour is more complex when $CO_2$ flows normal to the bedding plane than when it flows parallel to bedding. We also found that the differences in P-wave velocity images were associated both with the $CO_2$ phases and with heterogeneity of pore distribution in the rocks. Seismic images showed that the highest velocity reduction occurred for supercritical $CO_2$ injection, compared with gaseous or liquid $CO_$ injection. This result may justify the use of the seismic method for $CO_2$ monitoring in geological sequestration.

• Journal of the Korean earth science society
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• v.22 no.3
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• pp.223-236
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• 2001

The concentration of gaseous mercury (Hg) was measured at hourly intervals along with relevant environmental parameters from two monitoring stations (Hannam and Kwachun) in Seoul metropolitan city during September 1999 to July 2000. Irrespective of the environmental and areal differences in the two locations, the concentrations of observed Hg levels were remarkably compatible each other. The results showed that the mean Hg level in Hannam was measured to be 5.34${\pm}$3.92 ngm$^{-3}$ (N = 2576), while that of Kwachun was 5.25${\pm}$2.53 ngm$^{-3}$ (N = 1992). Using these measurement data, we inspected Hg distribution and behavior at various time scale. When the data were analyzed at 24 hr scale, the distribution patterns for the two areas were distinguished by enrichment in either night(Hannam) or day (Kwachun). The patterns for seasonal distributions were also opposing each other such as the occurrences of peak during winter (Hannam) or summer (Kwachun). In order to analyze the factors affecting Hg distributions between two sites over different time scale, we conducted both correlation and factor analysis on both all data sets and on seasonally divided data groups. Whereas Hg exhibits strong correlations with such parameters as PM (particulate matter), SO$_2$, and NO$_2$, its relationship with meteorological parameters was not significant enough in many cases. The results of factor analysis also indicated that the Hg levels are tightly associated with most pollutants, explaining the largest portions of statistical variance. According to our study, we conclude that patterns of Hg distributions can exhibit variable patterns depending on local source processes which we expect to be diverse among different areas.

• Journal of the Korean earth science society
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• v.22 no.6
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• pp.480-490
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• 2001

The soil-air exchange processes of Hg were investigated from the Hari area of Kang Hwa Island during the late March 2001. In the course of our study, we determined the concentration gradients of Hg and combined these gradient data with micrometeorological components to derive its fluxes. Results of our study indicate that the concentration levels of Hg in the study area are notably lower than those typically found in urbanized areas of Korea. However, the computed fluxes were seen to be significantly larger for relatively remote areas, reaching over 200 ng/m$^2$/hr. Comparison of environmental conditions shows that the concentrations of most pollutant species including NO$_X$ and PM were significantly higher during emission, while meteorological conditions were characterized by high temperature and low humidity. Results of correlation analysis also indicate that such pollutants as hydrocarbons, nitrogen oxides, and PM generally exhibit strong positive correlations with Hg-related parameters during emission events, while such relationships were reversed during dry deposition events. The results of our present study suggest the possibility that the concentrations and fluxes of total gaseous Hg observed during deposition events can be influenced by the processes that are also important for the fine, rather than coarse, size fraction of particles.