• The Korean Journal of Pesticide Science
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• v.4 no.4
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• pp.19-25
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• 2000

The leaching behaviour of quinclorac was elucidated using soil columns. On top of each glass column packed with a rice paddy soil up to the 30 cm height were applied three different treatments of [$^{14}C$]quinclorac: quincloiac only (T-1), quinclorac adsorbed onto active carbon (T-2), and quinclorac adsorbed onto a mixture of active carbon and $Ca(OH)_{2}$ (T-3). Half of the columns were planted with rice plants for 17 weeks and half of them unplanted for comparison. Average amounts of $^{14}C$-activity percolated from tile soil columns without rice plants in T-1, T-2, and T-3 were 81.1%, 27.8% and 48.0%, respectively, of tile originally applied $^{14}C$, whereas those with rice plants grown were 36.8%, 9.6% and 11.0%, respectively, indicating that the leaching of [$^{14}C$]quinclorac was significantly affected by vegetation and by treatment with the adsorbents. The bioavailability of the herbicide to rice plants in T-1, T-2, and T-3 were 13.6%, 11.0% and 13.9%, respectively. The residue levels of quinclorac in the edible part of rice grains would be far less than the maximum residue limit (MRL, 0.5 ppm). After the leaching, the amounts of $^{14}C$ remaining in soil in with rice planting T-1, T-2, and T-3 were 36.3%, 73.7%, and 61.8%, whereas those without rice planting were 19.7%, 71.1%, and 52.3%, respectively. The balance sheets indicate that [$^{14}C$]quinclorac translocated to rice shoots would be lost by volatilization and/or in other ways in T-1 and T-3. The $^{14}C$-activity partitioned into the aqueous phase of the leachates collected from all treatments was less than 7% of the total, but it increased gradually with time in the case of rice growing, suggesting tile formation of some polar degradation products.

• 대한공업교육학회지
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• v.42 no.1
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• pp.106-124
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• 2017

This study used the secondary Delphi method for experts, in order to propse a proper formation plan for the goal and curriculum of elementary and secondary invention/intellection property education. Its results are as following; First, the key objective of invention/intellectual property education for each school level is evaluated as appropriate. With regard to the key objective, elementary schools are aiming at 'fostering awareness and attitude for invention'(M=4.5), middle schools, 'understanding of invention process and method'(M=4.2), general high schools, 'application and evaluation of invention method'(M=4.1), and specialized high schools, 'understanding and application of Employee Invention'(M=4.6). The objective and goal of education for each school level are also evaluated as appropriate. Second, although the proper formation plans for a key learning element of elementary and secondary invention/intellectual property education were almost identical to an actual formation of preceding literature, overall change is required for the formation balance of each learning element, according to the objective and goal of school-leveled invention/intellectual property education. An appropriate formation shall be focusing on basic learning elements (A, B, C, D, E, and F) for elementary and middle schools(73.2%, 65.1%), lowering somewhat the former elements and increasing expanded learning elements for high schools(51.0%), which are connected to the invention, course(H), and patent application(K). Third, elementary and secondary invention/intellectual property education system should be oriented to its objective and goal. In order to reach this, an appropriate formation plan should be made for each school level, based on the principle of Tyler's learning organization, such as continuity, sequence and integration, which are key learning element. Specialized high schools, in particular, need to be differentiated from general ones, as well as elementary and middle schools. Additionally, for understanding and applying an employee invention, invention/intellectual property education system needs to be established in the phase of secondary occupational education.

• Korean Journal of Organic Agriculture
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• v.14 no.1
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• pp.55-67
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• 2006

A survey of 31 organic farmers were conducted to investigate the actual conditions of organic matter application. The amounts of organic matter application in the fields were higher in order of fruit, vegetable and rice farm. The average was 50 ton/ha in vegetable farms. In the green vegetable farms saw dust and animal manure were mainly utilized to make compost. Rice straw, wood chip, and forest bushes were also used for composting. In the fruit vegetable farms materials relatively lower in nitrogen content such as rice straw and cattle manure were used in vegetative period and materials higher in nitrogen content such as oil cake and wild grass were used in reproductive phase. Nutrient balance investigated in the farm in Icheon region who produce lettuce, angelica, and kale continuously in one cropping year indicated surplus in three major nutrients. Nitrogen and phosphorous were in excess by 29 and 10 kg respectively in the organic rice farm in yang-pyoung region. While soil chemical properties in the organic farms are within the adequate range in open field, it is much higher than the limits in the greenhouse soils. Overall application of organic matter is in an oversupply state. This results suggested that the organic matter management should be based on the soil conditions for sustainable cultivation. Chemical composition of organic matters and soil test reports should be considered prior to the application of organic matter.

• KSBB Journal
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• v.18 no.3
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• pp.211-216
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• 2003

The removal yield of dissolved organic matter in drinking water by biological activated carbon (BAC) process was investigated. The tested processes wer raw water-AC process (BAC1), raw water-ozonation-BAC process (BAC2), and raw water-ozonation-coagulation/sedimentation-BAC process (BAC3). The amounts of organic matter was measured as dissolved organic carbon (DOC), ulta-violet radiation at 254 nm wavelength ($UV_{254}$), total nitrogen (T-N), ammonia nitrogen (NH_3$-N), and total phosphate (T-P). As a results, 30.7% DOC was removed by BAC2 process, which showed higher removal efficiency than BAC1 or BAC3 processes. The removal yield of $UV_{254}$ in BAC1, BAC2, and BAC3 processes were observed as 45.3%, 44.6%, 58.4%, respectively. And the removal yield of ammonia nitrogen were 66%, 81%, 29% in each BAC processes. The optimal empty bed contact time (EBCT) of BAC processes was estimated as 10 minute. This study has shown that BAC process combined with ozone treatment was efficient for removing dissolved organic matter in water.

• Journal of the Korean Geographical Society
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• v.31 no.2
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• pp.138-159
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• 1996

There has been a tendency for Geomorphology and Climatology to be dominant in Physical Geography for 50 years in Korea. Physical Geography is concerned with the study of the totality of natural environment through the integrated approaches. But, an overall direction or a certain paradigm could not be found, because major sub-divisions of Physical Geography have been studied individually and the subjects and the approaches in studying Physical Geography are enormously diverse. A consensus of opinion could not also exist in deciding what kind of the sub-divisions should be included in the physical geography in general and how those should be summarized. Furthermore it would be considered imprudent to survey the studies of Physical Geography besides those of Geomorphology and Climatology due to the small number of researchers. Assuming that the rest of Physical Geographical studies with the exception of Geomorphological and Climatological studies are the Physical Geography in general, the studies of Physical Geogrpahy in general are summarized and several aspects are drown out as follows. First the descliption of all possible factors of natural environments was the pattern of early studies of Physical Geography and the tendency is maintained in the various kinds of research and project reports. Recently Physical Geographers have published several introductory textbooks or research monographs. In those books, however, the integrated approaches to Physical Geography were not suggested and the relationship between man and nature are dealt with in the elementary level. Second, the authentic soil studies of Physical Geographers are insignificant, because the studies of soil in Physical Geography have been mostly considered as the subsidiary means of Geomorphology Summarizing the studies of Soil Gegraphy by physical geographers and other Pedologists, the subjects are classified as soil-forming processes, soil erosions, soil in the tidal flat and reclaimed land, and soil pollution. Physical Geographers have focused upon the soil-forming processes in order to elucidate the geomorphic processes and the past climatic environment. The results of other subjects are trifling. Thirdy Byogeygrayhers and the results of studies are extremely of small number and the studies of Biogeography in Korea lines in the starting point. But, Biogeography could be a more unifying theme for the Physical-human Geography interface, and it would be expected to play an active part in the field of environmental conservation and resource management. Forth, the studies of Hydrogeography (Geographical Hydrology) in Korea have run through the studies of water balance and the morphometric studies such as the drainage network analysis and the relations of various kinds of morphometric elements in river. Recently, the hydrological model have introduced and developed to predict the flow of sediment, discharge, and ground water. The growth of groundwater studies is worthy of close attention. Finally, the studies on environmental problems was no mole than the general description about environmental destruction, resource development, environmental conservation, etc. until 1970s. The ecological perspectives on the relationship between man and nature were suggested in some studies of natural hazard. The new environmentalism having been introduced since 1980s. Human geographers have lead the studies of Environmental Perception. Environmental Ethics, Environmental Sociology, environmental policy. The Physical geographers have stay out of phase with the climate of the time and concentrate upon the publication of introductory textbooks. Recently, several studies on the human interference and modification of natural environments have been made an attempt in the fields of Geomorphology and climatology. Summarizing the studies of Physical Geography for 50 years in Korea, the integrated approaches inherent in Physical Geography disappeared little by little and the majol sub-divisions of Physical Ceography have develop in connection with the nearby earth sciences such as Geology, Meteorology, Pedology, Biology, Hydrology, etc been rediscovered by non-geographers under the guise of environmental science. It is expected that Physical Geography would revive as the dominant subject to cope with environmental problems, rearming with the innate integrated approaches.

• Korean Chemical Engineering Research
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• v.46 no.5
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• pp.988-993
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• 2008

The characteristics of NO oxidation using sodium chlorite ($NaClO_2$) powder have been investigated by a flow type packed-bed reactor, where the reaction temperature and the space velocity are varied in the range of $20{\sim}230^{\circ}C$ and $0.4-2.2{\times}10^5hr^{-1}$, respectively, and the simulation gas mixtures are composed of NO (0~200 ppm), $NO_2$ (0-200 ppm), $O_2$ (0~15%) and $H_2O$ (0~15%) within $N_2$ balance. It has been found that the oxidation efficiency of NO depends greatly on the reaction temperature, exhibiting the existence of critical reaction temperature at about $170^{\circ}C$ where the oxidation efficiency of NO is maximized and then abruptly decreased with further increase of reaction temperature, resulting in being negligible over $190^{\circ}C$. Such a behavior in the oxidation efficiency has been originated from the phase transition of $NaClO_2$ at about $170^{\circ}C$ to form $NaClO_3$, and NaCl which are chemically inactive toward the oxidation of NO. The chemical reaction of NO with $NaClO_2$ has been observed to produce $NO_2$, ClNO and $ClNO_2$, whereas that of $NO_2$ only OClO species. Additionally, we have also observed that the introduction of $O_2$ and $H_2O$ has little influence on the oxidation of NO.

• Journal of Korea Society of Industrial Information Systems
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• v.12 no.5
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• pp.1-13
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• 2007

In this research, we found out that bridging nodes have great effect on the robustness of protein-protein interaction networks. Until now, many researchers have focused on node's degree as node's essentiality. Hub nodes in the scale-free network are very essential in the network robustness. Some researchers have tried to relate node's essentiality with node's betweenness centrality. These approaches with betweenness centrality are reasonable but there is a positive relation between node's degree and betweenness centrality value. So, there are no differences between two approaches. We first define a bridging node as the node with low connectivity and high betweenness value, we then verify that such a bridging node is a primary factor in the network robustness. For a biological network database from Internet, we demonstrate that the removal of bridging nodes defragment an entire network severally and the importance of the bridging nodes in the network robustness.

• The Korean Journal of Pesticide Science
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• v.7 no.3
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• pp.176-181
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• 2003

The leaching behaviour of [aniline-$^{14}C$]mefenacet in soil was investigated using glass columns (5 cm I.D. $\times$ 30 cm. H) packed with two types of soils with different physicochemical properties. $^{14}C$-Mefenacet (8.33 kBq) and mefenacet (in total, 1.05 mg/kg) were treated onto soil columns and rice plants (Oryza sativa L.) were grown for 17 weeks on these columns. Leachates from the columns were collected at the rate of 122.5 mL per week. $^{14}C$-Activities leached from soil A (OM, 3.1%; CEC, 86 mmol(+)/kg; texture, loam) columns with and without rice plants were 1.95 and 4.19% of the originally applied, whereas those from soil B (OM, 1.3%; CEC, 71 mmol(+)/kg; texture, loam) were 2.69 and 7.05%, respectively. These results indicated that larger amounts of $^{14}C$ were percolated from soil B with less organic matter and from the columns without vegetation. $^{14}C$-Activities absorbed by rice plants from soil A and B were 8.95 and 8.47%, respectively, most of which remained in the root and shoot excluding unhulled grains and ears without grains. $62\sim73%$ of the originally applied $^{14}C$ remained in the depth of $0\sim5cm$ in soil. The mass balance indicated that the losses by volatilization and/or mineralization amounted to $3.4\sim9.2%$ of the originally applied. $^{14}C$-Radioactivities in the aqueous phase of the leachates ranged from 59.4 to 97.7% of the radioactivities in leachates, showing the fast transformation of mefenacet to the polar metabolites.

• Journal of the Mineralogical Society of Korea
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• v.23 no.1
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• pp.51-61
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• 2010

Ettringite $(Ca_6[Al(OH)_6]_2(SO_4)_3{\cdot}26H_2O)$ is a sulfate mineral that shows a complicate property in concrete. It is often called as "a cancer of concrete" because secondary ettringite formation in hardened concrete often cause expansion and cracking of concrete due to its expansive crystal structure. In the present study, we tested the possibility for crystal growth inhibition of secondary ettringite by crystallization inhibitors that are commercially used for scaling inhibitors in Korea. For the test, we developed a method of ettringite solution synthesis. Three types of crystallization inhibitors were selected and examined the effects On ettringite growth inhibition. The experimental results of ettringite solution synthesis indicated that ettringite was successfully synthesized under condition that the mass balance between calcium hydroxide saturated solution and aluminum sulfate solution was attained. Monosulfate and semisulfate were synthesized when the ratio of $Ca^{2+}$ ions to ${SO_4}^{2+}$ ions was increased. The induction time of ettringite crystallization was less than 2 min. and crystallization was almost completed within an hour. The experimental results of ettringite crystallization inhibition showed that organic PBCT (2-Phosphonobutane-1,2,4-Tricarboxylic Acid) and inorganic SHMP (Sodium Hexametaphosphate) were relatively less effective on ettringite crystallization inhibition under experimental conditions. However, organic HEDP (1-Hydoxyethylidene-1,1-Diphosphonic Acid) effectively prevented ettringite growth with producing amorphous gel phase materials up to inhibitor concentration 0.1 vol.% of aluminum sulfate solution.

• Korean Journal of Dental Materials
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• v.45 no.4
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• pp.257-274
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• 2018

The purpose of this study was to evaluate the effect of acid-treatment conditions on the surface properties of the RBM (Resorbable Blast Media) treated titanium. Disk typed cp-titanium specimens were prepared and RBM treatments was performed with calcium phosphate ceramic powder. Acid solution was mixed using HCl, $H_2SO_4$ and deionized water with 4 different volume fraction. The RBM treated titanium was acid treated with different acid solutions at 3 different temperatures and for 3 different periods. After acid-treatments, samples were cleaned with 1 % Solujet solution for 30 min and deionized water for 30 min using ultrasonic cleanser, then dried in the electrical oven ($37^{\circ}C$). Weight of samples before and after acid-treatment were measured using electric balance. Surface roughness was estimated using a confocal laser scanning microscopy, crystal phase in the surface of sample was analyzed using X-ray diffractometer. Surface morphology and components were evaluated using Scanning Electron Microscope (SEM) with Energy Dispersive X-ray spectroscopy (EDX) and X-ray Photoemission Spectroscopy (XPS). Values of the weight changes and surface roughness were statistically analyzed using Tukey-multiple comparison test (p=0.05). Weight change after acid treatments were significantly increased with increasing the concentration of $H_2SO_4$ and temperature of acid-solution. Acid-treatment conditions (concentration of $H_2SO_4$, temperature and time) did not produce consistent effects on the surface roughness, it showed the scattered results. From XRD analysis, formation of titanium hydrides in the titanium surface were observed in all specimens treated with acid-solutions. From XPS analysis, thin titanium oxide layer in the acid-treated specimens could be evaluated. Acid solution with $90^{\circ}C$ showed the strong effect on the titanium surface, it should be treated with caution to avoid the over-etching process.