• The Korean Journal of Pesticide Science
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• v.7 no.1
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• pp.32-37
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• 2003

Bacterial soft rot by Erwinia carotovora subsp. carotovora is one of the diseases causing the biggest problem in Chinese cabbage. Chemical screening was conducted to select effective agents for controlling bacterial soft rot. Control effect of antibiotics, plant activator, and Biokeeper (avirulent Erwinia) to soft rot were tested by in vitro assay, nursery test, and field experiment. The in vitro assay was done by paper disc method and potato slice method. The nursery test was performed by using mineral oil inoculation method with consistent disease induction. The in vitro assay showed that streptomycin, oxolinic acid, bronopol, and copper hydroxide significantly suppressed the growth of pathogenic bacterium and the decomposition of potato slice. However, plant activators including acibenzolar-S-methyl did not show the suppressive effect on the growth of pathogenic bacterium and the decomposition of potato slice. When applied by the nursery test condition using mineral oil inoculation method with Chinese cabbage 'Kangruckyeurum', Biokeeper, oxolinic acid, antibiotics streptomycin, validamycin, and copper compound provided 83.5%, 95.2%, 91.2%, 57.5% and 79.9% in control efficacy, respectively. However, the control effect of acibenzolar-S-methyl showed to be low to cause phytotoxicity. Also acibenzolar-S-methyl showed a significant control effect in the field experiment with Chinese cabbage 'Sanchon' in 2000, but the field experiment with Chinese cabbage 'Kangruckyeurum' in 2001 revealed it had phytotoxicity to Chinese cabbage. Such a difference was considered to be caused by differences in phytotoxic reaction of Chinese cabbage cultivars to the chemical. Streptomycin+copper, copper hydroxide and Biokeeper showed 79.7%, 71.9% and 60.9% in control efficacy, respectively, in the field experiment with Chinese cabbage 'Sanchon' in 2002.

• The Korean Journal of Malacology
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• v.28 no.3
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• pp.233-244
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• 2012

Goseong bay, located in southeast sea of Korea with an area of 2,100 ha, is a semi-enclosed bay well-known for oyster farming cultured in an extended range of 148 ha. The objective of this study is to provide the fundamental data in order to manage the effective sea area. A total 26 of surface sediment were collected from Goseong bay to evaluate their sedimentary environment and heavy metals. The loss on Ignition (LOI), C/N ratio, acid volatile sulfide (AVS) and heavy metals were analyzed. loss on ignition (LOI) of surface sediment range from 1.00% to 3.03% (average 2.00%). The carbonate content ranges from 0.52% to 4.29% (average 2.37%). C/N ratio of organic matter showed that most part of organic matter comes from neighboring continent. Acid volatile sulfide (AVS) value of surface sediment from 0.02 mg/g to 1.43 mg/g (average 0.24 mg/g). A ten element of surface sediments (Al, As, Cd, Cr, Cu, Hg, Ni, Pb, V, Zn) were calculated by enrichment factor (Ef) and the results show that some areas are highly polluted with respect Cu and Hg. The correlation matrix displays the existence of remarkable levels of correlation with both positive and negative values among different variable pairs. LOI and AVS showed both positive values. LOI and AVS values falls under 2% and 1%. Therefore, Goseong bay showed good in quality of sediment.

• Journal of Conservation Science
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• v.25 no.3
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• pp.283-291
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• 2009

Methyl Bromide that was used as fumigation gas turned out to be the substance of destroying the ozone layer. For that reason, at the Montreal Protocol in 1987 the use of methyl bromide was forbidden starting 2005 in the advanced country. Also according to the 2007 Bali Protocolly methyl bromide is expected to be forbidden and therefore the purpose of this study is to find out the effects of substitution fumigation gas (Ethylene Oxide+HFC 134a, Methyl Iodide, Cyanogen and Argon) on the metal(silver, copper and iron), wood(oregon pine), pigment(yellow, red, blue, white and black), textile(hemp, ramie, jute, silk1 and silk2 / indigo, safflower and cork) and paper. After the fumigation test, ethylene oxide+HFC 134a did not have changes in the weight and color of the material itself before and after the experiment. On exterior alteration, color change occurred partly on paper and metal. Also, in most materials color change extent was 0.5 to 1.5 on the average and showed scanty difference. The materials after the fumigation test with methyl iodide did not show weight changes after the test. However, color changes more than 1.0 was shown in most of the materials especially in dyed textile material. In blue pigment, the discoloration on the surface could be seen by naked eyes. Fumigation test with cyanogen gas did not show weight changes and discoloration is more than 1.5 before and after the test. The weight changes of test materials with the argon gas was decreased about 3 to 6%. It can be observed that discoloration on paper was generated. Color changes can be seen on jute dyed with safflower and cork for two weeks with argon gas and the extent was 6.3 and 6.0.

• Korean Journal of Environment and Ecology
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• v.30 no.6
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• pp.986-995
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• 2016

The objective of this study was to analyze the distribution of endangered fish species and elucidate their relations on chemical water quality, physical habitat conditions and ecological stream health. The dominant species in the watershed was Pseudopungtungia nigra (Pn), Gobiobotia macrocephala (Gm), Gobiobotia brevibarba (Gb), Liobagrus obesus (Lo), and Iksookimia choii (Ic) in the order. The species of Pn designated as "critical endangered species (I) (CER)", was most widely distributed species among the endangered species, so the designation of the species should be re-evaluated. The endangered species was most popular (4 species, 384 individuals) in the Cho-River region of eighteen lotic regions. According to the analysis of chemical tolerance limits in the habitats with endangered fish species, biological oxygen demand (BOD) and total phosphorus (TP) was analyzed as "very good" (Ia) and "good condition" in the chemical criteria of the Ministry of Environment, Korea. Also, chemical conditions, based on ammonia-N ($NH_{4+}$), total nitrogen (TN), phosphate-P ($PO_{4^-}P$) were much better in the habitat with endangered species (Hw) than the habitat without endangered species (Ho). In the meantime, the species of Ic showed wide ranges on the chemical tolerance, so physical habitat conditions, such as the size of substrate particles (sand) and hydrological regime, were considered as more important factors than the chemical water quality, if the water quality is not largely degraded. The endangered species were also more distributed in the high-order (4-6) streams than the low-order (1-3) streams. The evaluation of ecological stream health, based on multi-metric model of the Index of Biological Integrity (IBI), showed the large difference between the Hw (21.6, fair condition)and Ho (30.5, good condition), indicating that the habitat maintained well chemically and physically had higher distributions of endangered species. Overall, the designation of CER on the Pn should be re-evaluated due to wide-distributions, and the protections from water pollution and the habitat conservations on the endangered species are necessary in the watershed.

• Journal of Soil and Groundwater Environment
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• v.10 no.5
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• pp.25-36
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• 2005

Several metalliferous and coal mines, including Myungjin, Seojin and Okdong located at the upper watershed of Okdong stream, were abandoned or closed since 1988 due to the mining industry promotion policy. Thus these disposed an enormous amount of mining wastes without a proper treatment facilities, resulting in water pollution in the downstream areas. Acid mine drainage (AMD) and waste water effluents from the closed coal mines were very strongly acidic showing pH ranges of 2.7 to 4.5 and had a high level of Total Dissolved Solids (TDS) showing the ranges of 1,030 to 1,947 mg/L. Also heavy metal concentrations in these samples such as Fe, Cu, Cd and anion such as sulfate were very high. Concentrations of water soluble heavy metals in the Okdong streams were in the orders of Fe>Al>Mn>Zn>Cu>Pb>Cd, indicating Fe from the AMD and waste water effluents contributed greatly to the quality of water and soil in the lower watershed of Okdong stream. Copper concentrations in the effluents from the tile drainage of mine tailings dams were highest during the raining season. Water Pollution Index (WPI) of the surface water at the upper stream of Okdong river where AMD of the abandoned coal mines was flowed into main stream were in the ranges of 16.3 to 47.1. On the other hand, those at the mid stream where effluents from tailings dams and coal mines flowed into main stream were in the WPI ranges of 10.6 to 19.5. However, those at the lower stream were ranged from 10.6 to 14.9. These results indicated that mining wastes such as AMD and effluents from the closed mines were the major source to water pollution at the Okdong stream areas.

• Journal of the Korean Society for Marine Environment & Energy
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• v.17 no.4
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• pp.257-267
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• 2014

The distributions of trace metals in the East Sea were investigated during the R/V Lavrentyev cruise (July 2009) in which four transects from Russia shore to South were conducted to collect 25 surface water samples. The total dissolved concentrations of Cu and Ni were measured using ICP-MS, DRC-e. In the coastal area, their concentrations of Russia shore (Cu, 1.51; Ni, 1.82 nM) were 1.9 times for Cu and 2.0 times for Ni lower than Korea shore (Cu, 2.87; Ni, 3.71 nM). In the subregion, their concentrations of Warm region (Cu, 3.03; Ni, 2.28 nM) were higher for Cu than Cold region (Cu, 2.04; Ni, 2.28 nM). The distributions of Cu and Ni concentrations were divided by lowest level at $10^{\circ}C$ of water temperature. In this study period, the surface water temperatures of Russia shore and Japan basin were lower than $10^{\circ}C$ and them of Ulleung basin and Sakhalin shore were higher. Below $10^{\circ}C$, Cu and Ni concentrations increased when surface water temperatures decreased. Above $10^{\circ}C$, their concentrations increased with temperature, which showed highest concentrations in the Ulleung basin, directly influenced by flux from East Korean Warm Current. By comparing with other sea areas (Western Mediterranean, Atlantic), Cu concentrations in the East Sea were a little higher and Ni concentrations were lower. Particularly as the level of Cu in the offshore in the Ulleung basin were higher than in the coastal area, We can suggest that the atmospheric flux of Cu is relatively important in this area.

• Economic and Environmental Geology
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• v.12 no.1
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• pp.41-49
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• 1979

A literature review is made on the physical and chemical characteristics of clay minerals in acidic solutions from the mineralogical and hydrometallurgical viewpoints. Some of the important characteristics of clays are their ability to cation exchange, swelling, and incongruent dissolution in acidic solutions. Various clay minerals can take up metallic ions from solution via cation exchange mechanism. Generally, cation exchange capacity increases in the following order : kaolinite, halloysite, illite, vermiculite, and montmorillonite. In acidic solutions, the cation uptake such as copper by clay minerals is strongly inhibited by hydrogen and aluminum ions and thus is not economically significant factor for recovery of metals such as uranium and copper. In acidic solutions, the cation uptake is substial. Swelling is minimal at lower pH, possibly due to lattice collapse. Swelling may be controllable with montmorillonite type clays by exchanging interlayer sodium with lithium and/or hydroxylated aluminum species. The effect of add on clay minerals are : 1. Division of aggregates into smaller plates with increase in surface area and porosity. 2. Clay-acid reactions occur in the following order: (i) $H^+$ replacement of interlayer cations, (ii) removal of octahedral cations, such as Al, Fe, and Mg, and (iii) removal of tetrahedral Al ions. Acid attack initiates, around the edges of the clay particles and continued inward, leaving hydrated silica gel residue around the edges. 3. Reaction rates of (ii) and (iii) are pseudo-1st order and proportional to acid concentration. Rate doubles for every temperature increment of $10^{\circ}C$. Implications in in-situ leaching of copper or uranium with acid are : 1. Over the life span of the operation for a year or more, clays attacked by acid will leave silica gel. If such gel covers the surface of valuable mineral surfaces being leached, recovery could be substantially delayed. 2. For a copper deposit containing 0.5% each of clay minerals and recoverable copper, the added cost due to clay-acid reaction is about 1.5c/lb of copper (or 0.93 lbs of $H_2SO_4/1b$ of copper). This acid consumption by clay may be a factor for economic evaluation of in-situ leaching of an oxide copper deposit.

• Horticultural Science & Technology
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• v.30 no.5
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• pp.477-483
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• 2012

This study was carried out to investigate the influence of copper concentrations in fertilizer solution on the growth of and nutrient uptake by domestically bred strawberries. The characterization of toxicity symptoms as well as tissue analyses based on dry weight of above ground tissue were also conducted to determine the threshold levels in plants when toxicity developed in copper. The dry weights of the above ground tissue were not significantly different among the treatments of 0.25 mM to 1.0 mM in 'Keumhyang' and 'Maehyang' strawberries and that of 0.25 mM to 3.0 mM in 'Seolhyang' strawberry. This indicates that the 'Seolhyang' strawberry is more tolerant to copper toxicity than 'Keumhyang' or 'Maehyang' strawberries. Application of copper at high concentrations resulted in severe toxicity such as death of extensive areas of leaves. The lower leaves became yellow and die rapidly as the symptoms spread up the plants. The leaf blades and petioles died back to the crown and hang on by mechanical attachment. Symptoms of copper toxicity in lower leaves developed as browning on leaf margins and in patches between leaf veins that became necrotic. The elevation of copper concentrations in fertilizer solution did not influence the tissue phosphorus, potassium, calcium, and magnesium contents based on the dry weight of the above ground tissue. The tissue copper contents increased lineally as the copper concentrations in fertilizer solution were elevated. But the tissue iron, manganese and boron contents were not influenced by the concentrations. When the concentration of copper at which growth of a plant is retarded by 10% is regarded as threshold level, the copper contents based on dry weight of above ground plant tissue should be lower than 71.4, 57.9 and 74.8 $mg{\cdot}kg^{-1}$ in 'Keumhyang', 'Maehyang' and 'Seolhyang' strawberries, respectively. The symptom characterization and established threshold level in copper toxicity would help growers to prevent the reduction of crop growth and yield in 'Seolhyang' strawberry cultivation.

• Journal of radiological science and technology
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• v.31 no.3
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• pp.223-228
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• 2008

The most critical point in the medical use of radiation is to minimize the patient's entrance dose while maintaining the diagnostic function. Low-energy photons (long wave X-ray) among diagnostic X-rays are unnecessary because they are mostly absorbed and contribute the increase of patient's entrance dose. The most effective method to eliminate the low-energy photons is to use the filtering plate. The experiments were performed by observing the image quality. The skin entrance dose was 0.3 mmCu (copper) filter. A total of 80 images were prepared as two sets of 40 cuts. In the first set (of 40 cuts), 20 cuts were prepared for the non-filter set and another 20 cuts for the Cu filter of signal + noise image set. In the second set of 40 cuts, 20 cuts were prepared for the non-filter set and another 20 cuts for the Cu filter of non-signal image (noisy image) with random location of diameter 4 mm and 3 mm thickness of acryl disc for ROC signal at the chest phantom. P(S/s) and P(S/n) were calculated and the ROC curve was described in terms of sensitivity and specificity. Accuracy were evaluated after reading by five radiologists. The number of optically observable lesions was counted through ANSI chest phantom and contrast-detail phantom by recommendation of AAPM when non-filter or Cu filter was used, and the skin entrance dose was also measured for both conditions. As the result of the study, when the Cu filter was applied, favorable outcomes were observed on, the ROC Curve was located on the upper left area, sensitivity, accuracy and the number of CD phantom lesions were reasonable. Furthermore, if skin entrance dose was reduced, the use of additional filtration may be required to be considered in many other cases.

• Journal of the Korean Society of Radiology
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• v.14 no.5
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• pp.563-575
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• 2020

The purpose of this study is to evaluate the activation characteristics that occur in a linear accelerator for container security inspection. In the computer simulation design, first, the targets consisted of a tungsten (Z=74) single material target and a tungsten (Z=74) and copper (Z=29) composite target. Second, the fan beam collimator was composed of a single material of lead (Z=82) and a composite material of tungsten (Z-74) and lead (Z=82) depending on the material. Final, the concrete in the room where the linear accelerator was located contained magnetite type and impurities. In the research method, first, the optical neutron flux was calculated using the MCNP6 code as a F4 Tally for the linear accelerator and structure. Second, the photoneutron flux calculated from the MCNP6 code was applied to FISPACT-II to evaluate the activation product. Final, the decommissioning evaluation was conducted through the specific activity of the activation product. As a result, first, it was the most common in photoneutron targets, followed by a collimator and a concrete 10 cm deep. Second, activation products were produced as by-products of W-181 in tungsten targets and collimator, and Co-60, Ni-63, Cs-134, Eu-152, Eu-154 nuclides in impurity-containing concrete. Final, it was found that the tungsten target satisfies the permissible concentration for self-disposal after 90 days upon decommissioning. These results could be confirmed that the photoneutron yield and degree of activation at 9 MeV energy were insignificant. However, it is thought that W-181 generated from the tungsten target and collimator of the linear accelerator may affect the exposure when disassembled for repair. Therefore, this study presents basic data on the management of activated parts of a linear accelerator for container security inspection. In addition, When decommissioning the linear accelerator for container security inspection, it is expected that it can be used to prove the standard that permissible concentration of self-disposal.