• Korean Journal of Weed Science
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• v.31 no.3
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• pp.221-228
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• 2011

Weed control is of fundamental importance when planting horticultural crops, particularly during the establishment phase. Weeds compete for nutrients, water and light, and can severely threaten the survival and early growth of newly planted crops. Failure to control weeds represents one of the single most important factors leading to crop loss. Knowledge on the existence of the diversity of weed species in greenhouses is of our main concern in this study in order to develop a most efficient and effective weed control strategies. Sixty-two greenhouses were surveyed in 3 cities and counties of Gyeongnam area in March to October 2009 to investigate the feature of weed occurrence in polyvinyl chloride (PVC) after harvesting of the main crops. Forty-one weed species were identified and classified to 18 families which were composed of 14 annual weeds, 18 summer annual weeds and 9 perennial weeds. On the other hand, broadleaf, grasses and sedges recorded with 30, 7 and 4 weed species, respectively. Asteraceae was the most dominant weed species (9 species) noted followed by Poaceae (7 species), Cyperaceae (4 species), Caryophyllaceae and Brassicaceae (3 species respectively) and other families have 1~2 species. The dominant weed species occurred in the greenhouse based on the summed dominance ratio. These weeds were Digitaria sanguinalis, Cyperus iria, Portulaca oleracea, Rorippa islandica, Mazus japonicas, Cardamine flexousa, and Eclipta prostrata and others. Weed occurrence in the greenhouse after horticultural crops consisted of summer annuals (4 species), winter annuals (3 species), and perennial annuals (1 specie). The dominant species occurred in tilled soil based on summed dominance ratio of weeds were Cardamine flexousa (88.1%), Eclipta prostrate (57.4%) and Portulaca oleracea (55.2%). Comparison of weed occurrence was thoroughly surveyed also in which field without PVC, weed species were Portulaca oleracea (55.2), Eclipta prostrata (57.9%) and Trigonotis peduncularis (25.1%) and field with PVC, the identified weeds were Portulaca oleracea (98.75), Trigonotis peduncularis (49.1%), and Eclipta prostrata (36.8%).

• Journal of Mushroom
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• v.18 no.1
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• pp.1-9
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• 2020

Mycorrhiza refers to the association between a plant and a fungus colonizing the cortical tissue of the plant's roots during periods of active plant growth. The benefits afforded by plants from mycorrhizal symbioses can be characterized either agronomically, based on increased growth and yield, or ecologically, based on improved fitness (i.e., reproductive ability). In either case, the benefit accrues primarily because mycorrhizal fungi form a critical linkage between plant roots and the soil. The soilborne or extramatrical hyphae take up nutrients from the soil solution and transport them to the root. This mycorrhizae-mediated mechanism increases the effective absorptive surface area of the plant. There are seven major types of mycorrhizae along with mycoheterotrophy: endomycorrhizae (arbuscular mycorrhizae, AM), ectomycorrhizae (EM), ectendomycorrhizae, monotropoid, arbutoid, orchid, and ericoid. Endomycorrhizal fungi form arbuscules or highly branched structures within root cortical cells, giving rise to arbuscular mycorrhiza, which may produce extensive extramatrical hyphae and significantly increase phosphorus inflow rates in the plants they colonize. Ectomycorrhizal fungi may produce large quantities of hyphae on the root and in the soil; these hyphae play a role in absorption and translocation of inorganic nutrients and water, and also release nutrients from litter layers by producing enzymes involved in mineralization of organic matters. Over 4,000 fungal species, primarily belonging to Basidiomycotina and to a lesser extent Ascomycotina, are able to form ectomycorrhizae. Many of these fungi produce various mushrooms on the forest floor that are traded at a high price. In this paper, we discuss the benefits, nutrient cycles, and artificial cultivation of mycorrhizae in Korea.

• Nuclear Medicine and Molecular Imaging
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• v.40 no.4
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• pp.228-232
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• 2006

Purpose: electrophilic $^{18}F(T_{1/2}=110\;min)$ radionuclide in the form of $[^{18}F]F_2$ gas is of great significance for labeling radiopharmaceuticals for positron omission tomography (PET). However, its production In high yield and with high specific radioactivity is still a challenge to overcome several problems on targetry. The aim of the present study was to develop a method suitable for the routine production of $[^{18}F]F_2$ for the electrophilic substitution reaction. Materials and Methods: The target was designed water-cooled aluminum target chamber system with a conical bore shape. Production of the elemental fluorine was carried out via the $^{18}O(p,n)^{18}F$ reaction using a two-step irradiation protocol. In the first irradiation, the target filled with highly enriched $^{18}O_2$ was irradiated with protons for $^{18}F$ production, which were adsorbed on the inner surface of target body. In the second irradiation, the mixed gas ($1%[^{19}F]F_2/Ar$) was leaded into the target chamber, fellowing a short irradiation of proton for isotopic exchange between the carrier-fluorine and the radiofluorine absorbed in the target chamber. Optimization of production was performed as the function of irradiation time, the beam current and $^{18}O_2$ loading pressure. Results: Production runs was performed under the following optimum conditions: The 1st irradiation for the nuclear reaction (15.0 bar of 97% enriched $^{18}O_2$, 13.2 MeV protons, 30 ${\mu}A$, 60-90 min irradiation), the recovery of enriched oxygen via cryogenic pumping; The 2nd irradiation for the recovery of absorbed radiofluorine (12.0 bar of 1% $[^{19}F]fluorine/argon$ gas, 13.2 MeV protons, 30 ${\mu}A$, 20-30 min irradiation) the recovery of $[^{18}F]fluorine$ for synthesis. The yield of $[^{18}F]fluorine$ at EOB (end of bombardment) was achieved around $34{\pm}6.0$ GBq (n>10). Conclusion: The production of $^{18}F$ electrophilic agent via $^{18}O(p,n)^{18}F$ reaction was much under investigation. Especially, an aluminum gas target was very advantageous for routine production of $[^{18}F]fluorine$. These results suggest the possibility to use $[^{18}F]F_2$ gas as a electrophilic substitution agent.

• Horticultural Science & Technology
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• v.32 no.6
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• pp.872-878
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• 2014

This study aimed to enhance storage and freshness of strawberry fruits and foliage vegetables by spray treatment with Chlorella vulgaris as a bio-fertilizer. The tested strain, C. vulgaris CHK0008, was isolated from an organically cultivated rice paddy and identified as C. vulgaris by its morphology and 18S rDNA and 23S rDNA sequence homology. We successfully cultured C. vulgaris CHK0008 in BG11 modified medium (BG11MM) and adjusted $2.15{\times}10^6cell/mL$ C. vulgaris CHK0008 to one OD value by measuring the optical density at 680 nm using a UV-vis spectrophotometer. The soluble solid content of 'Seolhyang' and 'Yukbo' strawberry fruits treated by spray application with C. vulgaris CHK0008 was enhanced by 22.2% and 11.5% respectively, compared to untreated controls. Additionally, the decay rates of treated 'Seolhyang' and 'Yukbo' strawberry fruits decreased 63.8% and 74.4% respectively, compared to untreated control. Surface color changes and chlorosis of leaves in leaf vegetables such as lettuce, kale, red ornamental kale, white ornamental kale and beet were observed in samples treated with water spray for 10 days after cold storage. However, the decay rate of leafy vegetables treated with foliar application of 25% C. vulgaris CHK0008 liquid culture was significantly decreased compared to that of the untreated control during storage at $4^{\circ}C$.

• Journal of Animal Environmental Science
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• v.1 no.1
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• pp.9-19
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• 1995

This study was carried out to investigate the effect of sawdust bedding barn on manure handing, management labour and physiological aspect of dairy cows, and then to establish the criteria on the optimum utilization method of sawdust bedding barn. 46 tie stall barns and 49 sawdust bedding barns were surveyed to cmopare the milk productivity between two different barns, and also 5 tie stall barns, 15 sawdust bedding barns and 1 rice hull bedding barn were selected to study the utilization situation of sawdust barn in Kyung-Ki province area. The major results obtained were as follows; 1. The roof material of sawdust barn were consisted of 66% vinyl house, 23% PVC light and 11% slate and galvanum coated tin. Most of the floor structure was earth ground with the rate of the approximately 82%. 2. The average occupied area of sawdust bed per cow was 15.2 $m^2$, depth that 30 cm and the utilization period was 12 months. 3. Milk Yield was significantly higher at sawdust barn than at tie stall barn(P<0.01). Bacterial and somatic cell count in raw milk were less at the sawdust barn than in tie stall barn. However, there was not significance difference between two barns. 4. The labour hour needed to cow management in the sawdust barn was approximately 48% of that of tie stall barn. 5. The temperature and moisture content measured in sawdust bed were closely affected by seasonal ambient temperature. The skin and hair of cow were much cleaner at the PVC light roofed sawdust barn than any other roof materials. 6. The additives used for improving of fermentation did not show any effect on temperature and moisture content in sawdust bed. When the ambient temperature was $30.4^{\circ}C$, the surface temperature of measured 1 cm above the sawdust bed was $12.2^{\circ}C$ lower and the temperature of 100 cm above the sawdust bed was $2.4^{\circ}C lower under shading net facility than that of vinyl roofed one.7. The hoof length of miking cow was 7.95 cm in tie stall and 9.19 cm in sawdust barn with high significance (P<0.01). And disease occurence such as mastitis and foot-rot tended to decrease in the sawdust barn. 8. The number of total bacteria and coliform bacteria were less in the sawdust bed compared with earth ground resting area. And a parasite strongyloides papillosus was detected but without any infected cow. 9. The nitrate($NO_3N$) content in non-roofed earth ground resting area and earth ground under the sawdust bed was likely to pollute the ground water. 10. In economic point of view, rice hull bedding barn was the cheapest among different systems. And in the sawdust bedding barn PVC light + slate roofed barn was most desirable, and vinyl roofed one the least.

• Food Science of Animal Resources
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• v.29 no.2
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• pp.220-228
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• 2009

This study was conducted to determine the preblending effect of curing agents on the characteristics of mechanically deboned chicken meat (MDCM), including the pH, water-holding capacity (WHC), and stability under refrigeration conditions. MDCM was preblended with different curing agents [NaCl, 0.75 or 1.5%; sodium tripolyphosphate (STPP), 0.25 or 0.5%; ascorbic acid, 250 or 500 ppm; sodium nitrite, 75 or 150 ppm] and were stored at $4^{\circ}C$ overnight. The preblending of NaCl was found to have improved the WHC and emulsion stability; STPP was found to have improved the pH, WHC, and emulsion stability; and ascorbic acid or sodium nitrite did not affect the pH, WHC, and emulsion stability. The addition of ascorbic acid or sodium nitrite, however, decreased the 2-thiobarbituric acid (TBA) and volatile basic nitrogen (VBN) values of the preblended MDCM through the antioxidizing properties. The mixing effects of different curing agents on MDCM were also evaluated with nine different conditions. Among the treatments, the mixture of NaCl and STPP improved the WHC and emulsion stability due to the increased solubility of salt-soluble protein in the preblended MDCM. The mixture of NaCl, STPP, and ascorbic acid increased the pH, WHC, and emulsion stability, but the mixture of NaCl, STPP, ascorbic acid, and sodium nitrite improved the WHC, emulsion stability, and redness of the surface color with improved storage stability due to the decreased VBN and TBA values. As a result, the mixture of 1.5% NaCl, 0.5% STPP, 500 ppm ascorbic acid, and 75 ppm sodium nitrite showed the best properties as curing agents for MDCM preblending.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.4
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• pp.343-356
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• 2016

The Korea Radioactive Waste Agency (KORAD) has developed a dual-purpose metal cask for the dry storage of spent nuclear fuel that has been generated by domestic light-water reactors. The metal cask was designed in compliance with international and domestic technology standards, and safety was the most important consideration in developing the design. It was designed to maintain its integrity for 50 years in terms of major safety factors. The metal cask ensures the minimization of waste generated by maintenance activities during the storage period as well as the safe management of the waste. An activation evaluation of the main body, which includes internal and external components of metal casks whose design lifetime has expired, provides quantitative data on their radioactive inventory. The radioactive inventory of the main body and the components of the metal cask were calculated by applying the MCNP5 ORIGEN-2 evaluation system and by considering each component's chemical composition, neutron flux distribution, and reaction rate, as well as the duration of neutron irradiation during the storage period. The evaluation results revealed that 10 years after the end of the cask's design life, $^{60}Co$ had greater radioactivity than other nuclides among the metal materials. In the case of the neutron shield, nuclides that emit high-energy gamma rays such as $^{28}Al$ and $^{24}Na$ had greater radioactivity immediately after the design lifetime. However, their radioactivity level became negligible after six months due to their short half-life. The surface exposure dose rates of the canister and the main body of the metal cask from which the spent nuclear fuel had been removed with expiration of the design lifetime were determined to be at very low levels, and the radiation exposure doses to which radiation workers were subjected during the decommissioning process appeared to be at insignificant levels. The evaluations of this study strongly suggest that the nuclide inventory of a spent nuclear fuel metal cask can be utilized as basic data when decommissioning of a metal cask is planned, for example, for the development of a decommissioning plan, the determination of a decommissioning method, the estimation of radiation exposure to workers engaged in decommissioning operations, the management/reuse of radioactive wastes, etc.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.6 no.3
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• pp.201-210
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• 2001

Salinity, DIN, DIP, DIN/DIP and indigenous algal assay were determined to estimate the limiting nutrient for phytoplankton growth in Gwangyang Bay, South Sea of Korea. Seawater samples were collected at surface and bot-tom water in 4 November 1999 (dry season) and 2 September 2000 (after heavy rain). In 4 November 1999, the salinity, DIN, DIP and DIN/DIP were 29.92 psu, 13.59 ${\mu}M$, 3.41 ${\mu}M$ and 4.14 respectively. In 2 September 2000, These values were 24.62 psu, 27.77 ${\mu}M$, 2.82 ${\mu}M$ and 9.79 respectively. The DIN and DIP concentrations in this study were higher than Deukryang, Yeoja and Gamak Bay, South Sea of Korea. Especially, DIP concentration was 8 times high compared to Deutryang, Yeoja and Gamak Bay. The main sources of nitrogen seem to be freshwater runoff from Somjin River and industrial wastewater. But, the main sources of phosphorus seem to be industrial wastewater around Gwangyang Bay. The limiting nutrient was nitrogen at all station in 4 November 1999. The limiting nutrient was also nitrogen in 2 September 2000 in spite of heavy rain observed because of relatively much volume of phosphorus sup-plied from point sources than nitrogen. In case of below 20 psu in salinity by heavy rain, the limiting nutrient willbe shift from nitrogen to phosphorus at some area of Somjin River estuary. But the limiting nutrient will be never shift to phosphorus throughout Gwangyang Bay, eastern coast of Yeoja and Dolsan because of much volume of phosphorus runoff from point source in coastal area of Gwangyang Bay.

• Journal of Animal Science and Technology
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• v.47 no.5
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• pp.825-836
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• 2005

This study was carried out to evaluate the quality characteristics of the fermented pork with soy sauce, red pepper paste and soybean paste. The ham of pork were cut to cube (7 × 10 × 2 cm³) and Korea traditional seasonings such as soy sauce (T1), red pepper paste (T2), soybean paste (T3) were seasoned by the proportions of meat to seasonings (1:1), respectively. The pH of fermented pork with soybean paste seasoning were significantly higher compared to those for fermented pork with soy sauce and red pepper paste seasoning at 1 and 28 days of storage, but were significantly lower at 14 days of storage. The water-holding capacity of fermented pork with soy sauce seasoning were significantly higher compared to those for fermented pork with red pepper and soybean paste seasoning at 28 days of storage. The surface meat L* values of fermented pork with soybean paste seasoning were significantly higher compared to those for fermented pork with soy sauce and red pepper paste seasoning, but a* and b* values of fermented pork with red pepper paste seasoning significantly higher. The volatile basic nitrogen (VBN) of fermented pork with soybean paste seasoning were significantly lower compared to those for fermented pork with soy sauce seasoning at 1 and 28 days of storage. The shear force and thiobarbituric acid reactive substances (TBARS) of fermented pork with soybean paste seasoning were significantly lower compared to those for fermented pork with soy sauce and red pepper paste seasoning. The total plate counts of fermented pork with soybean paste seasoning were significantly higher compared to those for fermented pork with soy sauce and red pepper paste seasoning at 14 days of storage, but were significantly lower at 28 days of storage. The Escherichia coli of fermented pork with soy sauce and soybean paste seasoning were significantly lower compared to those for fermented pork with red pepper paste seasoning at 1 day of storage. The Lactobacilli spp. of fermented pork with red pepper paste seasoning were significantly lower compared to those for fermented pork with soy sauce and soybean paste seasoning.

• Journal of Animal Science and Technology
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• v.47 no.5
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• pp.837-850
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• 2005

This study was conducted to investigate the changes of quality characteristics on seasoned pork with Korean traditional 4 types seasoning such as soybean sauce(T1); Kimchi sauce(T2); pickled shrimps sauce(T3); onion sauce(T4). The seasoned samples were aged at 10±1℃ for 13 days. The results obtained were as follows; Except for T2, pH of treatments were significantly decreased(P<0.05) as aging period increased. Salinity(%) and saccharinity(%) of seasoned meat were tended to increased during aging period. Thiobarbituric acid reactive substances(TBARS) were increased significantly during storage in all treatment(P<0.05). T4 showed the highest TBARS among the all treatment groups. Volatile basic nitrogen(VBN) values of all treatments were significantly increased(P<0.05) as storage period increased. There were no significant differences in water holding capacity(WHC) among the all treatments, and those values were not changed by the passage of storage days. Shear force values of all treatments were tended to decreased by the passage of storage days. In surface color, the values of L*, a* and b* showed a tendency of increasing value along the storage days. The values of a* and b* of T2 were significantly higher than other treatments during aging period(P<0.05). In inner color, a* and b* values of T2 were significantly higher than those of other treatments during aging period(P<0.05). In the sensory evaluation of cooked meat, T3 treatment resulted in lower score in aroma, flavor, tenderness, juiciness and overall acceptability. The number of total plate counts and Lactobacilli spp. tended to increase with storage in all treatments group. The numbers of Escherichia coli were not changed by the passage of storage time.