• Progress in Medical Physics
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• v.21 no.2
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• pp.192-200
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• 2010

Cyberknife with small field size is more difficult and complex for dosimetry compared with conventional radiotherapy due to electronic disequilibrium, steep dose gradients and spectrum change of photons and electrons. The purpose of this study demonstrate the usefulness of Geant4 as verification tool of measurement dose for delivering accurate dose by comparing measurement data using the diode detector with results by Geant4 simulation. The development of Monte Carlo Model for Cyberknife was done through the two-step process. In the first step, the treatment head was simulated and Bremsstrahlung spectrum was calculated. Secondly, percent depth dose (PDD) was calculated for six cones with different size, i.e., 5 mm, 10 mm, 20 mm, 30 mm, 50 mm and 60 mm in the model of water phantom. The relative output factor was calculated about 12 fields from 5 mm to 60 mm and then it compared with measurement data by the diode detector. The beam profiles and depth profiles were calculated about different six cones and about each depth of 1.5 cm, 10 cm and 20 cm, respectively. The results about PDD were shown the error the less than 2% which means acceptable in clinical setting. For comparison of relative output factors, the difference was less than 3% in the cones lager than 7.5 mm. However, there was the difference of 6.91% in the 5 mm cone. Although beam profiles were shown the difference less than 2% in the cones larger than 20 mm, there was the error less than 3.5% in the cones smaller than 20 mm. From results, we could demonstrate the usefulness of Geant4 as dose verification tool.

• Journal of the Mineralogical Society of Korea
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• v.19 no.4 s.50
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• pp.265-275
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• 2006

It is in its infancy to use bacteria as a novel biotechnology for leaching precious and heavy metals from raw materials. The objective of this study was to investigate biogeochemical processes of iron leaching from magnetite reduction by iron-reducing bacteria isolated from intertidal flat sediments, southwestern part of Korea. Microbial leaching experiments were performed using commercial magnetite, Aldrich magnetite, in well-defined mediums with and without bacteria. Water soluble Fe production was determined by ICP analysis of bioleached samples in comparison to uninoculated controls, and the resulting precipitated solids were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The extent of iron leaching from magnetite in the aerobic conditions (Fe = 107 ppm) was higher than that in the anaerobic environments (Fe = 94 ppm). In the anaerobic conditions, Fe(III) in commercial magnetite was also reduced to Fe(II), but no secondary mineral phases were observed. Amorphous iron oxides formed in the medium under aerobic conditions where there was sufficient supply of oxygen from the atmosphere. SEM observation suggests that the reduction process involves dissolution-precipitation mechanisms as opposed to solid state conversion of magnetite to amorphous iron oxides. The ability of bacteria to leach soluble iron and precipitate amorphous iron oxides from crystalline magnetite could have significant implications for biogeochemical processes in sediments where Fe(III) in magnetite plays an important role in the largest pool of electron acceptor as well as the tool as a novel biotechnology for leaching precious and heavy metals from raw materials.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.6
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• pp.764-769
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• 1999

This study was designed to investigate the effects of sea tangle (Laminaria japonica) extract (Dasi-Ex group: dry base $4.0\%$) and fucoidan-added (Fuco-I, II, III group: fucoidan of $1,0\%,\;2.0\%,\;3.0\%$ added to Dasi-Ex) drinks on the formation of oxygen radicals and scavenger enzyme activities of stressed mice. ICR male mice (20 $\pm$2 g) were fed experimental diets and these drinks instead of water for 18 days including 4 days of sociopsychological stress. Dasi-Ex and Fuco-I, II and III groups resulted in a marked decreases $20\~40\%$ in basal oxygen radical (BOR) formation, and $15\~25\%$ in induced oxygen radical (IOR) formation compared with control group. Hydroxyl radical formations were significantly inhibited about $10\%$ in Dasi-Ex group, while remarkably inhibited $30\~40\%$ in Fuco-I, II and III groups. lipid peroxide (ISO) levels in Dasi-Ex group were not significantly different from those of control group, tut Fuco-I, II and III groups resulted in a significant decreases about $10\%$ in LPO levels compared with control group, Dasi-Ex, Fuco-I, II and III groups resulted in a marked decreases ($31\%,\;36\%,\;39\%$ and $42\%$, respectively) in oxidized protein levels through production of carbonyl group. Significant differences in nitric oxide (NO) levels in Dasi-Ex group were not obtained, but NO levels were slightly inhibited about $7\%$ in Fuco-I and II groups and $20\%$ in Fuco-III group compared with control group. Significant differences in superoxide dismutase (SOD) and catalase (CAT) activities in Dasi-Ex and Fuco-I groups were not obtained, but Fuco-II and III groups resulted in a significant increases $25\~40\%$ in SOD activities, and about $10\%$ in CAT activities compared with control group. These results suggest that the sociopsychological stress and aging process could be effectively inhibited by biological activity of sea tangle and fucoidan components.

• Korean Journal of Poultry Science
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• v.32 no.3
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• pp.187-193
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• 2005

This study was carried out to investigate the effect of the bleeding times(30sec., 90sec., 150sec.) at slaughtering process on meat quality and storage properties of broiler. The redness$(a^{\ast}\;value)$ of skin, wing, leg muscle decreased at high bleeding time(150sec.). However, there was no significant difference in breast muscle. WHC(water holding capacity) of breast muscle decreased from $63.64\%$ at low bleeding time(30sec.) to $61.06\%$ at high bleeding time. TBARS(thiobarbituric acid-reactive substance) values were 0.18 mgMA/kg at the low bleeding time, 0.16 mgMA/kg at the middle bleeding time(90sec.) and 0.21mgMA/kg high bleeding time on 3 days of storage. Total aerobic plate counts(TPC) were $6.25logCFU/cm^2$ at the low bleeding time, $6.25logCFU/cm^2$ at the middle bleeding time and $6.53logCFU/cm^2$ at the high bleeding time. The TPC was increased as the bleeding time increased. In conclusion, meat color of chicken were acceptable when the carcasses were slaughtered at the high bleeding time.

• Korean Journal of Food Science and Technology
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• v.2 no.2
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• pp.17-25
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• 1970

Juice were extracted from fresh leaves of 70 species of plants growing in Korea by mincing and pressing the resulting pulp through a cotton cloth. Leaf protein concentrates could be prepared from many species of land and water plants that are at present economically unimportant. The choice of plants is of considerable important. Total-N, protein-N and pH determinations were made on the extracts, and total-N remaining in the fibre were calculated. Leaf protein concentrates were precipitated from the extracts at $75{\sim}80^{\circ}C$, and analysed total-N as protein-N of products. The present paper deals with the calculated yields of leaf protein concentrates from various plants, relations between yield of leaf protein concentrates and total-N of leaves, or pH of extracts, and the amino acid compositions of leaf protein concentrates. Results are summarized as follows. 1. Spinach and radish were the best sources of easily extractable, but good results were also obtained with indian mustard, kail, chenopod, red bean, cucumber, squash, houndberry, white flowered gourd, potato, Humulus japonicus, arrowroot and soybean as a good resources for the production of leaf protein concentrates. 2. In general, the greater the protein content of leaves the greater the yield of leaf protein concentrates. However, there are some plants difficult to make a adequate protein extraction by a simple mechanical process. 3. It was to be expected that leaf protein concentrates would be more extractable with the higher pH of extracts. There were a poor yield of the leaf protein concentrate in the pH values lower than 5.50 of the first extracts. 4. Protein content of the leaf protein concentrate shows marked differences, depending on species and season. It ranged between 29 to 80% of protein contents. However, the majority of plants yielded products containing more than 50% of protein. Products containing more than 75% of protein were obtained from two species of radish and indian mustard. Cabbage and Digitaria sanguinalis cilialis (summer) made products containing 29 to 32% of protein. 5. The amino acid composition of leaf protein concentrates was not greatly altered by species of plants. On an amino acid compositional basis, the leaf protein concentrate has a favorable balance of essential and non-essential amino acids, the only exception being methionine, which was usually low in all cases.

• 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.

• Land and Housing Review
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• v.3 no.4
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• pp.369-378
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• 2012

In France, there are many forms of organizations based on the intercommunal solidarity for city development and management. The purpose of the collaboration among Communes is to achieve high quality and well-equipped service-delivery system through co-operation of public services needed grand finances : water supply and sewage system and waste disposal system etc. The cooperation among French Communes and its effects, even though these were owing to the existing French local administration system, continued throughout regional co-management and social co-development process. This study suggested some characteristics and implications of the collaborative-style French new-town development and management organizations focused on the EPA, SAN and CA. First, the role of developmental corporation like EPA and its collaborative structure of decision-making are meaningful, because in these ways many related Communes could share a goal of new town development. Second, the way of new town corporation (SAN) is important in the sense of enabling the Communes to collaborate with each others while maintaining autonomy, so those are not simply state-directed objects, which was very difficult in the former French local administration system. Finally, transforming to CA (Communautes d'agglomeration:city community), EPA as an intercommunal corporation is possible to extend its purpose to the domain of regional planning including new town and periphery areas and change its position to a subject which can practice Commune's sustainable development according to stages of city's development and maturity. The most important implication of this study on urban development in Korea is that administrative consultative council or association among local governments and related authorities need to be established and effectively operate because multi-stakeholders could share a goal of urban development and management through that.

• Economic and Environmental Geology
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• v.43 no.1
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• pp.13-20
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• 2010

Acid mine drainage (AMD) from abandoned mine sites typically has low pH and contains high level of various heavy metals, aggravating ground- and surface water qualities and neighboring environments. This study investigated removal of heavy metals in a biological treatment system, mainly focusing on the removal by adsorption on a substrate material. Bench-scale batch experiments were performed with a mushroom compost to evaluate the adsorption characteristics of heavy metals leached out from a mine tailing sample and the role of SRB in the overall removal process. In addition, adsorption experiments were perform using an artificial AMD sample containing $Cd^{2+}$, $Cu^{2+}$, $Pb^{2+}$ and $Zn^{2+}$ to assess adsorption capacity of the mushroom compost. The results indicated Mn leached out from mine tailing was not subject to microbial stabilization or adsorption onto mushroom compost while microbially mediated stabilization played an important role in the removal of Zn. Fe leaching significantly increased in the presence of microbes as compared to autoclaved samples, and this was attributed to dissolution of Fe minerals in the mine tailing in a response to the depletion of $Fe^{3+}$ by iron reduction bacteria. Measurement of oxidation reduction potential (ORP) and pH indicated the reactive mixture maintained reducing condition and moderate pH during the reaction. The results of the adsorption experiments involving artificial AMD sample indicated adsorption removal efficiency was greater than 90% at pH 6 condition, but it decreased at pH 3 condition.

• Journal of Food Hygiene and Safety
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• v.25 no.1
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• pp.49-58
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• 2010

The objectives of this study were to investigate the microbial contamination levels on food service in university and to provide the information of microbial contamination to improve food safety. A total of 288 samples were collected during summer and winter season between 2006 and 2008 from 4 food services located in the university in Western Gyeongnam and were used to detect sanitary indicator bacteria [aerobic plate count (APC), coliform, and Escherichia coli] and pathogenic bacteria (Staphylococcus aureus, Salmonella spp.). As a result, APC and coliform for hand and kitchen utensils which are used often by the employee were detected at high levels of 1.1~5.5 and 1.3~5.3 log CFU/($100\;cm^2$, hand), respectively. The contamination levels of APC and coliform in cooked foods and drinking water were 0.8~6.4 and 1.3~5.0 log CFU/(g, mL), respectively. Especially, the cooked foods showed the highest contamination for APC (2.1~6.4 log CFU/g) and coliform (1.0~5.0 log CFU/g). We think the reason that the cooked foods may be contaminated with APC and coliform on cooking process by using employee's hand and kitchen utensils. Moreover, S. aureus for hand and kitchen utensils was detected at levels of 2.8~3.0 and 2.0~2.3 log CFU/(g, hand), but Salmonella spp. was not detected. According to the above results, contamination levels of the samples were mostly decreased irrespective of summer and winter season. The results obtained indicated that it is necessary to periodic monitoring for microorganism contamination and education about personal and environmental hygiene to employee for ensuring food safety of food service in university.

• Journal of Animal Environmental Science
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• v.16 no.2
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• pp.135-142
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• 2010

The composting of layer manure is economical and efficiently process. In this study, the variation of composting characteristics in layer manure was investigated according to air supply capacity. The fermented compost was added in layer manure and mixed with sawdust inside composting reactors. The level of air supply capacity was varied in the range of $50{\sim}200\;{\ell}/m^3/min$. During composting the temperature variations of composting piles was different the temperatures of composting piles for T-1 ($50\;{\ell}/m^3/min$) and T-2 ($100\;{\ell}/m^3/min$) were reached at $40^{\circ}C$ and $50^{\circ}C$ within 2 days, respectively. For T-3 ($150\;{\ell}/m^3/min$) and T-4 ($200\;{\ell}/m^3/min$), their temperatures was $60^{\circ}C$ within same days and maintained during 8 days. Water contents decreased according to the air supply capacity; 8.9%, 15.4%, 18.0% and 18.6% for T-1, T-2, T-3 and T-4. The weight ratios of T-1, T-2, T-3 and T-4 were reduced to 12.8%, 15.6%, 18.1% and 17.9%, respectively. The decreasing volumetric ratios of T-1, T-2, T-3 and T-4 were 18.0%, 21.0%, 22.3% and 22.0%. The oxygen discharge concentrations during composting were 12 ppm for T-1, T-2 and 9 ppm for T-3 and T-4. After composting, fertilizer components such as total nitrogen (TN) and phosphorous pentoxide ($P_2O_5$) were examined at each air supply capacity. Nitrogen contents of the T-1, T-2, T-3 and T-4 were 0.75%, 0.74%, 0.72% and 0.64%. Also, The contents of $P_2O_5$ were 0.35%, 0.40%, 0.38% and 0.42% for T-1, T-2, T-3 and T-4.