• Journal of The Korean Society of Grassland and Forage Science
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• v.30 no.4
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• pp.333-342
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• 2010

Corn is very important forage in Korea. The great part of them is utilized as silage. Generally, it contains a lot of grains that is feed of animal. This experiment was conducted to evaluation of fermentation ability of microbes for corn silage inoculant. Good lactic acid bacteria were isolated from good corn silage by plating MRS agar containing 0.02% sodium azide, and assessed by growing and acid producing ability in MRS broth. Six lactic acid bacteria were selected, and were found to be Gram positive, rods and catalase negative and were identified to be lactobacillus plantarum (C3-2, B13-1, CC9-1), Lactobacillus fermentum (C11-4), Lactobacillus paracasei (B14-1), and Leuconostoc lactis (A3-1) on the basis of the biochemical characteristics and utilization of substrates. Corn was ensiled at ripen stage following treatment with selected five lactic acid bacteria, two commercial inoculant, and no additive (control). After 2 month, B13-1 and CC9-1 bacteria inoculated silage were lower pH and higher lactic acid content than others treatments. The Flieg's score and grade of B13-1 and CC9-1 bacteria treated silage were higher than commercial inoculant. According to this experiment, lactobacillus plantarum B13-1 and CC9-1 strain were recommendable for good inoculant of corn silage.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.407-408
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• 2011

Natural boron consists of two stable isotopes 10B and 11B with natural abundance of 18.8 atom percent of 10B and 81.2 atom percent of 11B. The thermal neutron absorption cross-section for 10B and 11B are 3837 barn and 0.005 barn respectively. 10B enriched specific compounds are used for control rods and as a reactor coolant additives. In this work 2 methods for boron enrichment were analysed: 1) Gas irradiation in static conditions. Dissociation occurs due to multiphoton absorption by specific isotopes in appropriately tuned laser field. IR shifted laser pulses are usually used in combination with increasing the laser intensity also improves selectivity up to some degree. In order to prevent recombination of dissociated molecules BCl3 is mixed with H2S 2) SILARC method. Advantages of this method: a) Gas cooling is helpful to split and shrink boron isotopes absorption bands. In order to achieve better selectivity BCl3 gas has to be substantially rarefied (~0.01%-5%) in mixture with carrier gas. b) Laser intensity is lower than in the first method. Some preliminary calculations of dissociation and recombination with carrier gas molecules energetics for both methods will be demonstrated Boron separation in SILARC method can be represented as multistage process: 1) Mixture of BCl3 with carrier gas is putted in reservoir 2) Gas overcooling due to expansion through Laval nozzle 3) IR multiphoton absorption by gas irradiated by specifically tuned laser field with subsequent gradual gas condensation in outlet chamber It is planned to develop software which includes these stages. This software will rely on the following available software based on quantum molecular dynamics in external quantized field: 1) WavePacket: Each particle is treated semiclassicaly based on Wigner transform method 2) Turbomole: It is based on local density methods like density of functional methods (DFT) and its improvement- coupled clusters approach (CC) to take into account quantum correlation. These models will be used to extract information concerning kinetic coefficients, and their dependence on applied external field. Information on radiative corrections to equation of state induced by laser field which take into account possible phase transition (or crossover?) can be also revealed. This mixed phase equation of state with quantum corrections will be further used in hydrodynamical simulations. Moreover results of these hydrodynamical simulations can be compared with results of CFD calculations. The first reasonable question to ask before starting the CFD simulations is whether turbulent effects are significant or not, and how to model turbulence? The questions of laser beam parameters and outlet chamber geometry which are most optimal to make all gas volume irradiated is also discussed. Relationship between enrichment factor and stagnation pressure and temperature based on experimental data is also reported.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.3
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• pp.40-48
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• 2014

In this study, experimental research was carried out to evaluate and improve the seismic performance of reinforced concrete beam-column joint regions using strengthening materials (embedded CFRP rod and CFRP sheet) in existing reinforced concrete building. Therefore it was constructed and tested six specimens retrofitting the beam-column joint regions using such retrofitting materials. Specimens, designed by retrofitting the beam-column joint regions of existing reinforced concrete building, were showed the stable failure mode and increase of load-carrying capacity due to the effect of crack control at the times of initial loading and confinement of retrofitting materials during testing. Specimens RBCJ-SRC2, designed by the retrofitting of CFRP Rod and CFRP Sheet in reinforecd beam-column joint regions were increased its maximum load carrying capacity by 1.97 times and its energy dissipation capacity by 2.08 times in comparison with standard specimen RBCJ for a displacement ductility of 4 and 7. Also, specimens RBCJ-SRC2 were increased its maximum load carrying capacity by 1.09~1.11 times in comparison with specimen RBCJ-SR series. And Specimens RBCJ-CS, RBCJ-SR series, RBCJ-SRC2 were increased its energy dissipation capacity by 1.10~2.30 times in comparison with standard specimen RBCJ for a displacement ductility of 5, 6.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.588-588
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• 2013

Nanoscale noble-metals have attracted enormous attention from researchers in various fields of study because of their unusual optical properties as well as novel chemical properties. They have possible uses in diverse applications such as devices, transistors, optoelectronics, information storages, and energy converters. It is well-known that nanoparticles of noble-metals such as silver and gold show strong absorption bands in the visible region due to their surface-plasmon oscillation modes of conductive electrons. Silver nanocubes stand out from various types of Silver nanostructures (e.g., spheres, rods, bars, belts, and wires) due to their superior performance in a range of applications involvinglocalized surface plasmon resonance, surface-enhanced Raman scattering, and biosensing. In addition, extensive efforts have been devoted to the investigation of Gold-based nanocomposites to achieve high catalytic performances and utilization efficiencies. Furthermore, as the catalytic reactivity of Silver nanostructures depends highly on their morphology, hollow Gold nanoparticles having void interiors may offer additional catalytic advantages due to their increased surface areas. Especially, hollow nanospheres possess structurally tunable features such as shell thickness, interior cavity size, and chemical composition, leading to relatively high surface areas, low densities, and reduced costs compared with their solid counterparts. Thus, hollow-structured noblemetal nanoparticles can be applied to nanometer-sized chemical reactors, efficient catalysts, energy-storage media, and small containers to encapsulate multi-functional active materials. Silver nanocubes dispersed in water have been transformed into Ag@Au nanoboxes, which show highly enhanced catalytic properties, by adding $HAuCl_4$. By using this concept, $SiO_2$-coated Ag@Au nanoboxes have been synthesized via galvanic replacement of $SiO_2$-coated Ag nanocubes. They have lower catalytic ability but more stability than Ag@Au nanoboxes do. Thus, they could be recycled. $SiO_2$-coated Ag@Au nanoboxes have been found to catalyze the degradation of 4-nitrophenol efficiently in the presence of $NaBH_4$. By changing the amount of the added noble metal salt to control the molar ratio Au to Ag, we could tune the catalytic properties of the nanostructures in the reduction of the dyes. The catalytic ability of $SiO_2$-coated Ag@Au nanoboxes has been found to be much more efficient than $SiO_2$-coated Ag nanocubes. Catalytic performances were affected noteworthily by the metals, sizes, and shapes of noble-metal nanostructures.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.39 no.6
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• pp.42-48
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• 2002

The design, construction and performance test of a convenient multi-purpose irradiator is described. A multi-purpose irradiator using Cesium-137 has been developed for studies of low dose radiation effects in biology and for calibration of Thermo Luminescent dosimeter(TLD). During the operation, three rods of radioactive material which are 10cm in length revolve 180 degrees and irradiate biological samples, or TLD, and return to their shielded position, after the programmed time. A programmable Logic Controller(PLC) controls the sequence of operation, interlock, motor rotation and safety system. The rotation speed of biological samples can vary up to 20 RPM. A real time monitoring system was also incorporated to check and control the operation status of the irradiator. The capacity of the irradiation chamber was 4.5 liters. The isodose distribution at arbitrary vertical planes was measured by using film dosimetry. The dose-rate was 0.13 cGy/min in air and 0.11 cGy/min in water equivalent material in the case of Cesium-137. Range of activity was 2 Ci. The homogeneity of dose distribution in the chamber was ${\pm}$7%. The actual radiation level on the surface was within permissible levels. The irradiator had a maximum 0.35 mR/min radiation leakage on its surface.

• Journal of Energy Engineering
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• v.13 no.4
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• pp.242-258
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• 2004

The duplex burnable poison absorbers concept was suggested by Korea Atomic Energy Research Institute. This BP rod is composed of inner region of natural U-Gd$_2$O$_3$ and outer shell of enriched UO$_2$-Er$_2$O$_3$. It is expected that this burnable absorber has same reactivity control capability with gadolinia burnable absorber used in extened fuel cycle. In order to evaluate the nuclear feasibility of duplex BPs, the nuclear design characteristics were compared with that of four types of burnable absorbers; gadolinia, erbia, IFBA, dysprosia duplex BP on 24 months fuel cycle for Korean Standard Nuclear Power plants. According to the evaluation results of nuclear characteristics, the duplex BPs were better than other BPs on k-infinitives, reactivity holddown worth (RHW), pin power peaking and moderator temperature coefficient (MTC). The possibility of nuclear core design was also confirmed based on the optimized fuel assemblies which were searched for a sensitivity analysis. Characteristics of core design with duplex BPs was compared with that of reference core with gadolinia BPs for cycle length, power peaking and MTC. The duplex BP core had a little longer cycle length by 4 to 7 days because of increased amount of fissile in enriched uranium at the outer shell of duplex BP In case of power peaking F$\_$Q/ of duplex BP core was reduced from 1.5773 to 1.5335. MTC was also less -0.48 pcm/C than that of reference core. Finally, evaluation of fuel cycle economy was performed for the manufacturing feasibility test and fuel cost evaluation with duplex BPs. Fuel cycle economy of duplex BP core almost was equivalent with that of gadolinia BP core.

• Nuclear Engineering and Technology
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• v.55 no.12
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• pp.4447-4464
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• 2023

This paper focuses on the development of a new computational model of the CNESTEN's TRIGA Mark II research reactor using the 3D continuous energy Monte-Carlo code TRIPOLI-4 (T4). This new model was developed to assess neutronic simulations and determine quantities of interest such as kinetic parameters of the reactor, control rods worth, power peaking factors and neutron flux distributions. This model is also a key tool used to accurately design new experiments in the TRIGA reactor, to analyze these experiments and to carry out sensitivity and uncertainty studies. The geometry and materials data, as part of the MCNP reference model, were used to build the T4 model. In this regard, the differences between the two models are mainly due to mathematical approaches of both codes. Indeed, the study presented in this article is divided into two parts: the first part deals with the development and the validation of the T4 model. The results obtained with the T4 model were compared to the existing MCNP reference model and to the experimental results from the Final Safety Analysis Report (FSAR). Different core configurations were investigated via simulations to test the computational model reliability in predicting the physical parameters of the reactor. As a fairly good agreement among the results was deduced, it seems reasonable to assume that the T4 model can accurately reproduce the MCNP calculated values. The second part of this study is devoted to the sensitivity and uncertainty (S/U) studies that were carried out to quantify the nuclear data uncertainty in the multiplication factor k_eff. For that purpose, the T4 model was used to calculate the sensitivity profiles of the k_eff to the nuclear data. The integrated-sensitivities were compared to the results obtained from the previous works that were carried out with MCNP and SCALE-6.2 simulation tools and differences of less than 5% were obtained for most of these quantities except for the C-graphite sensitivities. Moreover, the nuclear data uncertainties in the k_eff were derived using the COMAC-V2.1 covariance matrices library and the calculated sensitivities. The results have shown that the total nuclear data uncertainty in the k_eff is around 585 pcm using the COMAC-V2.1. This study also demonstrates that the contribution of zirconium isotopes to the nuclear data uncertainty in the k_eff is not negligible and should be taken into account when performing S/U analysis.

• Journal of dental hygiene science
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• v.16 no.4
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• pp.284-292
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• 2016

Water supplied through dental unit waterlines (DUWLs) has been shown to contain high number of bacteria. To reduce the contamination of DUWLs, it is essential to develop effective disinfectants. It is, however, difficulty to obtain proper DUWL samples for studies. The purpose of this study was to establish a simple laboratory model for reproducing DUWL biofilms. The bacteria obtained from DUWLs were cultured in R2A liquid medium for 10 days, and then stored at $-70^{\circ}C$. This stock was inoculated into R2A liquid medium and incubated in batch mode. After 5 days of culturing, it was inoculated into the biofilm formation model developed in this study. Our biofilm formation model comprised of a beaker containing R2A liquid medium and five glass rods attached to DUWL polyurethane tubing. Biofilm was allowed to form on the stir plate and the medium was replaced every 2 days. After 4 days of biofilm formation in the laboratory model, biofilm thickness, morphological characteristics and distribution of the composing bacteria were examined by confocal laser microscopy and scanning electron microscopy. The mean of biofilm accumulation was $4.68{\times}10^4$ colony forming unit/$cm^2$ and its thickness was $10{\sim}14{\mu}m$. In our laboratory model, thick bacterial lumps were observed in some parts of the tubing. To test the suitability of this biofilm model system, the effectiveness of disinfectants such as sodium hypochlorite, hydrogen peroxide, and chlorhexidine, was examined by their application to the biofilm formed in our model. Lower concentrations of disinfectants were less effective in reducing the count of bacteria constituting the biofilm. These results showed that our DUWL biofilm laboratory model was appropriate for comparison of disinfectant effects. Our laboratory model is expected to be useful for various other purposes in further studies.

• Korean journal of applied entomology
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• v.18 no.1 s.38
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• pp.1-10
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• 1979

An inclusion forming virus isolated from a fan webworm, Hyphantria cunea, in 1975 was identified as a nuclear polyhedrosis virus. With the virus isolated in Korea, it was considered that the virus would be one of the valuable microorganism in microbial control. In this connection, 1) the shape and size of the virus for identification, 2) susceptibility of the various instar larvae to the virus, 3) the effects of storage condition on the pathogenicity and the cross infection of the virus to the larvae of Bombyx mori were examined. The results are summarized as follows; 1. The polyhedron was tetrahedron or hexahedron of $2\mu$ in size and the rod-shaped virus particles consisting of $2\~14$ rods in a bundle were $330m{\mu}\times35m{\mu}$ in size. 2. The hexagonal nuclear polyhedra were found only in the nucleus of the midgut cells but were variable in size. 3. The $LD_{50}$ values for the various instar larvae of H. cunea were $8.377\times10^4\;PIBs/ml$ for the second, $4.974\times10^5\;PIBs/ml$ for the fifth instar larvae. The $LT_{50}values$ for $10^6\;PIBs/ml$ were 9.6 days for the second, 11.5 days for the third, 12.0 days for the fourth and 17 days for the fifth instar larvae. 4. The susceptibility of H. cunea to the nuclear polyhedrosis virus was greater in the first generation than in the second generation. 5. The effect of the storage conditions on the pathogenicity of the nuclear polyhedra was less in refrigerator $(5^{\circ}C)$ and in freezing $(-80^{\circ}C)$ than in room temperature $(18.5^{\circ}C)$, especially as air-dried polyhedra than as suspension. The pathogenicity of the polyhedra seemed to decrease by sunlight during storage as cadavers, since rather greater decrease in pathogenicity was found in sunny condition than in shady condition. 6. The effective spray concentration was $6.4\times10^7\;PIBs/ml$ in the field and its $LT_50$ values for the third and the fifth instar larvae were 4.8 days and 14.2 days, respectively. 7. No cross infections were found in the nuclear polyhedrosis virus between H. cunea and B. mori. larvae.

• Tuberculosis and Respiratory Diseases
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• v.49 no.2
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• pp.217-224
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• 2000

Background : It is well known that when macrophages are stimulated with endotoxin, they produce a wide variety of cytokine mediators, including TNF-$\alpha$ and IL-1$\beta$. However, there is an alteration in the macrophages' responsiveness when they are challenged with repeated bouts of endotoxin, termed "endotoxin tolerance" which is regarded as a self-protective phenomenon from continuous stimulation. In this study, endotoxin tolerance in the peripheral blood monocytes of sepsis patients was evaluated. Methods : Fourteen patients with organism-documented sepsis were included. The severity of illness was evaluated by APACHE II score. Peripheral blood monocytes were isolated from the patients and diluted to $1{\times}10^5$ well. After stimulation with endotoxin (LPS of E. coli O114 : B4, 100 ng/ml), they were incubated at $37^{\circ}C$ in 5% $CO_2$ incubator for 24 hours. Supernatant was collected for the measurement of TNF-$\alpha$ and IL-1$\beta$ with ELISA method. Peripheral blood monocytes of seven healthy volunteers were used as control. Results : The APACHE II score (mean$\pm$SD) of the patients at the time of blood sampling was 12.2$\pm$5.7. The primary infection foci were urinary tract infection, pneumonia, subacute bacterial endocarditis, and catheter related infection, etc. The causative organisms were gram negative rods (10 cases), gram positive cocci (6 cases) with two cases of mixed infection. Serum TNF-$\alpha$ could be measured in 4 cases with 29.9$\pm$27.7 pg/ml. Serum IL-1$\beta$was measurable in only one patient. The TNF-$\alpha$ level of supernatant of cultured peripheral blood monocytes was 2,703$\pm$2,066 pg/ml in patients and 2,102$\pm$1914 pg/ml in controls. The IL-1$\beta$level of supernatant was 884$\pm$1,050 pg/ml in patients and 575$\pm$558 pg/ml in controls. There was no difference of TNF-$\alpha$ and IL-1$\beta$ level between patients and controls. Conclusion : We cannot prove the phenomenon of endotoxin tolerance in this study. Future study needs to be focused on the more severe sepsis patients who were taken for sampling earlier. Addition of serum to the culture medium could be an another valuable option for the success of this study.