• Earthquakes and Structures
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• v.19 no.6
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• pp.445-457
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• 2020

An ultra-high voltage (UHV) transmission system has the advantages of low circuitry loss, high bulk capacity and long-distance transmission capabilities over conventional transmission systems, but it is easier for this system to cross fault rupture zones and become damaged during earthquakes. This paper experimentally and numerically investigates the seismic responses and collapse failure of a UHV transmission tower-line system crossing a fault. A 1:25 reduced-scale model is constructed and tested by using shaking tables to evaluate the influence of the forward-directivity and fling-step effects on the responses of suspension-type towers. Furthermore, the collapse failure tests of the system under specific cross-fault scenarios are carried out. The corresponding finite element (FE) model is established in ABAQUS software and verified based on the Tian-Ma-Qu material model. The results reveal that the seismic responses of the transmission system under the cross-fault scenario are larger than those under the near-fault scenario, and the permanent ground displacements in the fling-step ground motions tend to magnify the seismic responses of the fault-crossing transmission system. The critical collapse peak ground acceleration (PGA), failure mode and weak position determined by the model experiment and numerical simulation are in relatively good agreement. The sequential failure of the members in Segments 4 and 5 leads to the collapse of the entire model, whereas other segments basically remain in the intact state.

• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.2
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• pp.101-108
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• 2008

This study attempted to develop the technology by gaseous ozone for decontaminating building affected by a model of biological weapon agent(Bacillus subtilis spores) instead of Bacillus anthracis spore. The use of ozone is attractive method from a practical point of view of decontamination procedure since it has strong oxidation power but no residue after application. We examined the disinfection efficiency of gaseous ozone to Bacillus subtilis spores which suspension was sprayed on different material surfaces and dried. Three different types of gaseous ozone was applied : dry ozone, dry ozone with humidified air, and water bubbled wet ozone. Dry ozone(1500ppm) failed to achieve any significant inactivation for 2hrs. However, six log reduction of B. subtilis spore was achieved within 30min by 1500ppm of water bubbled wet ozone. This result shows the noticeable inactivation efficiency by gaseous ozone compared with previous studies. Good performance by wet ozone was also found for military material surface.(i.e. : gas mask hood, protective garments, army peinted metal surface).

• Korean Journal of Animal Reproduction
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• v.16 no.1
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• pp.15-20
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• 1992

These experiments were undertaken to investigate the rate of in vitro fertilization of bovine follicular oocytes treated with glycosaminoglycans(GAGs). Bovine follicular oocytes were obtained from the ovary of slaughtered animal and matured in media containing the various concentrations of hydluronic acid, chondroitin sulfate or heparin for 26 hours. Epididymal spermatozoa were capacitated and insemination was made by introducing about 10~15 matured oocytes into the suspension of spermatozoa. Six hour after insemination the eggs were transferred to TCM-199 supplemented with FCS(10%) and then examined the embryo development. After in vitro insemination, percentages of ova fertilized were 61.3 or 48.3%, respectively, for the cumulus intact or removed in the percentages of GAGs. However, in case of cumulus-free oocytes treated with GAGs, the fertilization rates were 58.8, 62.1, 58.8, and 61.8%, respectively, showing significant effect compared to 48.3% in cumulus-free oocytes. Our findings suggest that cnondroitin sulfate and heparin are superior to hyaluronic acid in the fertilizatin and pronuclear formation of bovine oocytes.

• The Journal of Advanced Prosthodontics
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• v.3 no.1
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• pp.20-24
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• 2011

PURPOSE. The aim of this study was to identify in vitro antimicrobial activity of the tissue conditioner containing silver nanoparticles on microbial strains, Staphylococcus aureus, Streptococcus mutans and Candida albicans. MATERIALS AND METHODS. Experimental disc samples ($20.0{\times}3.0$ mm) of tissue conditioner (GC Soft-Liner, GC cooperation, Tokyo, Japan) containing 0.1 - 3.0% silver nanoparticles (0%: control) were fabricated. Samples were placed on separate culture plate dish and microbial suspensions (100 ${\mu}L$) of tested strains were inoculated then incubated at $37^{\circ}C$. Microbial growth was verified at 24 hrs and 72 hrs and the antimicrobial effects of samples were evaluated as a percentage of viable cells in withdrawn suspension (100 ${\mu}L$). Data were recorded as the mean of three colony forming unit (CFU) numerations and the borderline of the antimicrobial effect was determined at 0.1% viable cells. RESULTS. A 0.1% silver nanoparticles combined to tissue conditioner displayed minimal bactericidal effect against Staphylococcus aureus and Streptococcus mutans strains, a 0.5% for fungal strain. Control group did not show any microbial inhibitory effect and there were no statistical difference between 24 hrs and extended 72 hrs incubation time (P > .05). CONCLUSION. Within the limitation of this in vitro study, the results suggest that the tissue conditioner containing silver nanoparticles could be an antimicrobial dental material in denture plaque control. Further mechanical stability and toxicity studies are still required.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.6
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• pp.581-586
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• 2010

Generally, electrokinetic potential has been considered as an intensive property. In other words, electrokinetic potential is not affected by the amount of particulate matter. Montmorillonite, one of essential inorganic matter, was chosen to measure electrokinetic potential. The result of electrokinetic potential measuring experiment showed that the value observed to decrease as the amount of montmorillonite clay increased. This is due to the fact that total ions that adsorbed per unit mass were decreased as the amount of montmorillonite was increased. As a result, electrokinetic potential is considered as an extensive property. By using these results, total interaction energy of suspension was also checked, and revealed that total interaction energy was decreased as the amount of montmorillonite increased.

• Wind and Structures
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• v.31 no.5
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• pp.393-402
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• 2020

Long-span bridges with high flexibility and low structural damping are very susceptible to the vortex-induced vibration (VIV), which causes extremely negative impacts on the ride comfort of vehicles running on the bridges. To assess the ride comfort of vehicles running on the long-span bridges subjected to VIV, a coupled wind-vehicle-bridge system applicable to the VIV case is firstly developed in this paper. In this system, the equations of motion of the vehicles and the bridge subjected to VIV are established and coupled through the vehicle-bridge interaction. Based on the dynamic responses of the vehicles obtained by solving the coupled system, the ride comfort of the vehicles can be evaluated using the method given in ISO 2631-1. At last, the proposed framework is applied to several case studies, where a long-span suspension bridge and two types of vehicles are taken into account. The effects of vehicle speed, vehicle type, road roughness and vehicle number on the ride comfort are investigated.

• Korean Journal of Veterinary Research
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• v.26 no.1
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• pp.109-115
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• 1986

Experiments were performed on mice to investigate the effects of a polycyclic aromatic hydrocarbon, 3-methylcholanthrene (MCA) on Arthus reaction, delayed-type hypersensitivity (DTH) and antibody production to sheep red blood cells (SRBC). Mice were sensitized iv with 0.1ml of 1% SRBC suspension were treated with a single ip injection of olive oil alone or with different doses of MCA in oil (0.5~50mg/Kg) at various time before (-) or after (+) sensitization (day 0) and were challenged at 4 days after SRBC. Arthus reaction was measured at 3 hours after challenge and other responses at 24 hours. Treatment with MCA inhibited Arthus reaction and DTH to SRBC, measured by footpad swelling reaction, and this immunosuppressing effect was dependent on the dose and time of MCA treatment in relation to SRBC sensitization. Humoral immune responses as measured by serum hemagglutinin-and hemolysin-titers to SRBC were significantly depressed when MCA was injected before or at the same time of sensitization. However, the response was slightly depressed when injected after SRBC. These results indicate that MCA suppress the function of the cells involved in immune responses.

• The Korean Journal of Food And Nutrition
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• v.21 no.3
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• pp.269-274
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• 2008

Plants have long been used as a food source in Korea. In this study, we investigated the combined immunomodulative effects of a water extract mixture of(pine needles, Sedum sarmentosum Bunge, hijkiaorme, buckwheat and Peril a leaves) on Balb/c mice $7{\sim}8$ weeks old. The mice were fed a chow diet ad libitum and the plant extract was orally administered every other day for four weeks at two different concentrations(50 and 500 mg/kg BW). After preparing the single-cell suspension, splenocyte proliferation was determined by the MTT(3-[4,5-di-methylthiazol-2-y]-2,5-diphenyl terazolium bromide) assay. After 48hrs of incubation with the mitogens(ConA or LPS) splenocyte from the mice groups administered 50 and 500 mg/kg BW of the plant extract showed a significant increased in proliferation compared to the control group. A hemolytic plague forming cell assay was used to indicate antibody production against sheep red blood cells(SRBC). The number of antibody-secreting cells T-dependent antigen. The result of this study suggest that supplementation with this plant extract may regulate immune function by increasing splenocyte proliferation and the number of plaque forming cells.

• International Journal of Railway
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• v.4 no.2
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• pp.34-41
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• 2011

Using a test run data, the dynamics of the interface between the catenary and pantograph constituting the current collection system in high-speed trains are investigated. The test run signals are analyzed to determine the dynamic parameters critical to the current collection performance. There are found to be frequency components of the pantograph motion that are dependent on train speed as well as components that are stationary such as the resonant mode of the panhead suspension in the pantograph. From contact force measurement using load cell, the mean contact force was found to be stable while the fluctuating component was found to be dependent on the range of the frequency of the pantograph motion taken into account. The finding implies that numerical investigations reported in the literature that are based on lumped element models of the catenary and/or pantograph provide accurate predictions on the mean value but are of limited use in estimating fluctuation of the contact force. It is concluded that simulation studies based on lumped-element models which do not incorporate panhead structural vibration modes is inaccurate at high train speeds.

• KSBB Journal
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• v.8 no.1
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• pp.62-68
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• 1993

Transformed rice plantlet were recovered from protoplasts by electroporation with the plasmld pB 1121, which contain the plant expressible NPT-II and GUS genes. Embryonic cell suspension culture was established with embryonic callus induced from mature seeds of rice (Oryza sativa L. cv. Dong-jin) on the MS medium supplemented with 2.0 mg/l 2,4-D, 0.5 mg/l kinetin, 3% sucrose. Protoplasts isolated from embryonic cell suspensions were electroplated and then poterltialty-transformed tissues were selected by growth on the medium containing 200 mg/l kanamycin sulfate. When subjected to GUS assay, they stained blue, indicating the expression of the inserted GUS genes. Plantlets were regenerated from electroplated protoplasts on the hormone free MS medium. Transferred foreign genes in the plants were confirmed by southern hybridization. These results support use of electroporation for transformation of these important cereal plants.