• Progress in Medical Physics
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• v.12 no.1
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• pp.95-102
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• 2001

The intracavitary cones were designed which were made of stainless steel and have scratched inside cone to be generated electron scatter and designed to be attached easily to the LINAC collimator and controlled cones length to be contacted smoothly between the patient and the cone tip. Two types of intracavitary cones were designed. One is the straight end cones with circular opening on the distal end and the other is 30 degree beveled end cones with elliptical opening on the distal end. Each type of intracavitary cone ranged in daimeter from 2.5 cm to 3.5 cm and required a separate set of lower trimmer annulias cone diameter. The film phantom was designed with an internal cassette that accurately aligned the film edge with the film phantom surface. Film optical density data were measured by photodensitometer(Wellhofer 700i) Dosimetry measurements were made to commission the LINAC for 6 - 20 MeV electron using the intracavitary cones. Isodose curves were measured for all energy and cones combinations. Output is defined as the maximum dose per MU along the clinical central axis in water at 113 cm SSD. Calibration output, defined to be the output for the 15cm$\times$15cm diameter straight cone, was adjusted to 1.00 cGy/MU at each energy according to the TG-21 protocol.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.493-493
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• 2014

The manufacturing cost of thin-film photovoltics can potentially be lowered by minimizing the amount of a semiconductor material used to fabricate devices. Thin-film solar cells are typically only a few micrometers thick, whereas crystalline silicon (c-Si) wafer solar cells are $180{\sim}300\mu}m$ thick. As such, thin-film layers do not fully absorb incident light and their energy conversion efficiency is lower compared with that of c-Si wafer solar cells. Therefore, effective light trapping is required to realize commercially viable thin-film cells, particularly for indirect-band-gap semiconductors such as c-Si. An emerging method for light trapping in thin film solar cells is the use of metallic nanostructures that support surface plasmons. Plasmon-enhanced light absorption is shown to increase the cell photocurrent in many types of solar cells, specifically, in c-Si thin-film solar cells and in poly-Si thin film solar cell. By proper engineering of these structures, light can be concentrated and coupled into a thin semiconductor layer to increase light absorption. In many cases, silver (Ag) nanoparticles (NP) are formed either on the front surface or on the rear surface on the cells. In case of poly-Si thin film solar cells, Ag NPs are formed on the rear surface of the cells due to longer wavelengths are not perfectly absorbed in the active layer on the first path. In our cells, shorter wavelengths typically 300~500 nm are also not effectively absorbed. For this reason, a new concept of plasmonic nanostructure which is NPs formed both the front - and the rear - surface is worth testing. In this simulation Al NPs were located onto glass because Al has much lower parasitic absorption than other metal NPs. In case of Ag NP, it features parasitic absorption in the optical frequency range. On the other hand, Al NP, which is non-resonant metal NP, is characterized with a higher density of conduction electrons, resulting in highly negative dielectric permittivity. It makes them more suitable for the forward scattering configuration. In addition to this, Ag NP is located on the rear surface of the cell. Ag NPs showed good performance enhancement when they are located on the rear surface of our cells. In this simulation, Al NPs are located on glass and Ag NP is located on the rear Si surface. The structure for the simulation is shown in figure 1. Figure 2 shows FDTD-simulated absorption graphs of the proposed and reference structures. In the simulation, the front of the cell has Al NPs with 70 nm radius and 12.5% coverage; and the rear of the cell has Ag NPs with 157 nm in radius and 41.5% coverage. Such a structure shows better light absorption in 300~550 nm than that of the reference cell without any NPs and the structure with Ag NP on rear only. Therefore, it can be expected that enhanced light absorption of the structure with Al NP on front at 300~550 nm can contribute to the photocurrent enhancement.

• Conservation Science in Museum
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• v.16
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• pp.82-95
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• 2015

Old Monk by Yun Duseo is realized to use silver paper which is made of rarity material. This sudy investigates reason why silver, that is easily discoloration in environmental condition, is susceptible in present. The method was the surface treatment materials and the base fiber through direct observation, optical instruments and XRF analysis. Based on these results, reproducing experiment was conducted to research materials in paper of Old Monk and the surface treatment technique. The results, the paper was treated 'Dochim' with a mineral having polygonal crystals for improving smoothness and density. XRF analysis result showed high calcium content, therefore, the paper was not used silver, it guess pulverized shells of abalone or other types of shellfish. Accordingly, the research was narrowed down to shells with shiny, reflective surfaces which at the same time contain high amounts of calcium. A new experiment was conducted using unprocessed abalone shells. Through the reproducing experiment, shellfish has high possibility as used mineral in paper. Notwithstanding, this experiment was unable to precisely reproduce the smoothness and shine of the original paper. Further research may therefore be needed.

• Parasites, Hosts and Diseases
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• v.50 no.3
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• pp.191-197
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• 2012

Seroepidemiological changes of Toxoplasma gondii infection among the residents of the islands of Gangwha-gun, Incheon for 2 years were surveyed and evaluated by ELISA using a crude extract antigen. In 2010, sera of 919 adult residents in Gyodong-myeon and 313 adults in Samsan-myeon were collected and checked for IgG antibody titers, which showed 14.5% (133 sera) and 19.8% (62 sera) positive rates, respectively. In 2011, sera of 955 adults in Gyodong-myeon and 341 adults in Samsan-myeon were examined, which showed an increase of positive rates to 23.8% (227 sera) and 31.7% (108 sera), respectively. Totally, the seroprevalence of the first year was 15.8% and it increased rapidly to 25.8% in the second year. The positive rates of both sexes increased simultaneously with the significant ratio of males to females by 1.7-2.2 fold (P<0.05). In both myeons, 661 sera were collected every year and showed changes in optical density (OD) in 177 sera; newly found as positives in 73 persons (11.0%), negative conversion in 10 persons (1.5%), and maintained or increased in 94 persons (14.2%). This rapid increase in the prevalence of toxoplasmosis in Gangwha islands may be due to in part peculiar changes in the toxoplasmic environment of the islands and presumably the consumption of the pork bred domestically within the islands or imported from high endemic nations. It is necessary to find out symptomatic toxoplasmic patients and confirm the risk factors for further infection in the islands of Gangwha-gun.

• Fire Science and Engineering
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• v.31 no.2
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• pp.52-60
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• 2017

Numerical simulations were performed to evaluate the habitability of an operator for a cabinet fire in the main control room of a nuclear power plant presented in NUREG-1934. To this end, a Fire Dynamics Simulator (FDS), as a representative fire model, was used. As the criteria for determining the habitability of operator, toxic products, such as CO, were also considered, as well as radiative heat flux, upper layer temperature, smoke layer height, and optical density of smoke. As a result, the probabilities of exceeding the criteria for habitability were evaluated through the sensitivity analysis of the major input parameters and the uncertainty analysis of fire model for various fire scenarios, based on V&V (Verification and Validation). Sensitivity analyses of the maximum heat release rate, CO and soot yields, showed that the habitable time and the limit criterion, which determined the habitability, could be changed. The present methodology will be a realistic alternative to enhancing the reliability for a habitability evaluation in the main control room using uncertain information of cabinet fires.

• Korean Journal of Food Science and Technology
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• v.31 no.3
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• pp.764-770
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• 1999

Antimicrobial activities were assayed through the hot-water extracts from 41 species of medicinal plants against Helicobacter pylori which is known as the ulcerogenic phathogen. Opuntia ficus-indica, Houttuynia cordata, Sinomenium acutum, and Coptis japonica showed the MIC at the concentrations less than 100 ppm, Pulsatilla koreana, Forsythia koreana, Rheum undulatum, and Perilla frutescens less than 200 ppm, Belamcanda chinensis, Arctium lappa, Cassia tora, Citrus tachibana, Siegesbeckia orientalis, and Caesalpinia sappan less than 300 ppm by the 2-fold dilution method. In disc method only three of them were confirmed to have antimicrobial activities which were increased in the order Perilla frutescens, Coptis japonica, Caesalpinia sappan. Three extracts were partitioned with chloroform, ethyl acetate and butanol in sequence and examined for the activity to inhibit H. pylori. The major ativities were observed in ethyl acetate fraction of Caesalpinia sappan, butanol fraction of Perilla frutescens, butanol and chloroform fraction of Coptis japonica. The partitioned fractions were found to have increased antimicrobial activities in all extracts. The experiments in which the extracts were added into urea R broth containing the crude urease derived from H. pylori resulted in the increase of pH and optical density at 560 nm to 8.15 and 1.7 respectively. Urease activity of H. pylori was inhibited over 80% by Caesalpinia sappan, Perilla frutescens, and Coptis japonica, of which Caesalpinia sappan suppressed up to 95%.

• Korean journal of food and cookery science
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• v.27 no.4
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• pp.17-26
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• 2011

This study was performed to analyze the antibacterial activity against food hazardous microorganisms and antimutagenic effects of Sanguisorba officinalis L. ethanol extracts on Salmonella Typhimurium TA100. The antibacterial activity was evaluated by paper disc diffusion assay, minimum inhibition concentration (MIC), and optical density of the culture with the ethanol extract for 24 hr. Antibacterial activity was tested with seven microorganisms including Escherichia coli, Escherichia coli O157:H7, Pseudomonas aeruginosa, Salmonella Typhimurium, Listeria monocytogenes, Bacillus cereus, and Staphylococcus aureus. The paper disc diffusion assay showed distinct clear inhibition zones around the discs treated with the extract for five microorganisms, except Escherichia coli and Escherichia coli O157:H7. MIC values were 0.625-2.5 mg/mL for these five strains that showed clear zones. The time-kill assay was consistent with the results from the paper disc diffusion assay and MIC test. Additionally, antimutagenicity of the extract was determined using the Ames test. The ethanol extract at 5 mg/plate inhibited 72.42% and 89.85% of mutagenicity induced by 4-nitroquinoline 1-oxide and sodium azide, respectively. These results demonstrate that the ethanol extract from S. officinalis L. has remarkable antibacterial activity and antimutagenicity.

• Korean Journal of Veterinary Research
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• v.39 no.1
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• pp.159-168
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• 1999

Swine whipworm(Trichuris suis) is cosmopolitan nematode which can cause serious pathology in immature stage(larva2~larva5) of infected pigs, such as anorexia, diarrhea, anemia, and death in heavy infections. In this larval stages, it is very difficult to diagnose the infection of whipworm and to differentiate from other common swine gastrointestinal disorders such as 21 day scours which are associated with TGE virus, rota virus, coccidium, and the stress of weaning. In this experiment, the isolated antigens of Trichuris spp. were carried out to examine the structure and specificity of antigens and to select the reasonable antigens which would be used in serological diagnosis by electrophoresis, Western blotting, ELISA. The results of this experiment were as follows; 1. The common fractions of each Trichuris suis antigen were identified 28,32,45, 80kDa by SDS-PAGE with silver stain and four major fractions could be detected in positive swine sera by Western blot analysis. 2. The OD(optical density) values of somatic and excretory-secretory antigens which were reacted against positive(negative) sera from pigs infected with Trichuris suis by ELISA reader were; 1) OD values($mean{\pm}SD$) of adult somatic antigen against positive(negative) sera were $0.30{\pm}0.12(0.09{\pm}0.006)$ and third-stage larva of somatic antigen were $0.28{\pm}0.038(0.10{\pm}0.005)$. And OD values of excretory-secretory antigens of adult and third-stage larva were $0.24{\pm}0.031(0.11{\pm}0.005)$ and $0.08{\pm}0.013(0.10{\pm}0.003)$, respectively. 2) OD values of adult somatic, larval somatic antigen and adult excretory-secretory antigen response to positive sera were significantly (p<0.01) associated with negative swine sera. And the Cut-off OD values(minimum positive value) were determined to be mean negative value plus 3 SD that would minimized the risk of false positives. 3. The OD values of somatic antigens of T suis and T vulpis against swine positive(negative) sera were $0.30{\pm}0.120(0.09{\pm}0.006)$ and $0.25{\pm}0.141(0.09{\pm}0.003)$. These data mean that the somatic antigens of T suis and T vulpis were able to diagnose T vulpis infection in dogs as well as T suis infection in pigs. These results suggest that somatic antigen of third-stage larva and excretory-secretory antigen of adult T suis could be used the diagnostic antigen by serological test(ELISA) in immature Trichuris spp. infection.

• Korean Journal of Microbiology
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• v.40 no.4
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• pp.263-268
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• 2004

Two species of halophilic bacteria were isolated from five salted seafoods and identified by 16S rDNA sequenc­ing homology. One was identified as Halomonas subglaciescola and other four strains were belong to Halomo­nas marina. The identity of all isolates with standard organisms was above $95\%.$ H. subglaciescola, H. marina IN, and H. marina SH-2 grew in salinity condition from $3%\;to\;18\%$ NaCl but growth of H. marina SQ and H. marina SH-l grew in salinity environment from $8\%\;to\;17\%.$ Maximum biomass of H. subglaciescola, H. marina IN, H. marina SQ, H. marina SH-1, and H. marina SH-2 growing in LB medium containing $15\%$ NaCl were about 3.2, 4.5, 4.5, 5.7, and 4.2, however the maximum biomass in LB medium containing $5\%$ NaCl were about 2.2, 1.1, 0.7, 0.2, and 2.4 as optical density at 660 nm, respectively. In scanning electron micrograph, unknown material (mucus) attached to outer membrane of all isolates was observed. When mucus isolated from halophilic bacterial cell was added to culture of E. coli, E. coli grew in medium containing $15\%$ NaCl.

• Journal of Energy Engineering
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• v.17 no.4
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• pp.189-197
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• 2008

In this study, a system to measure continuously the fuel concentration in a steady flow rig on the basis of Rayleigh scattering is presented. The system can be employed to measure both the temporal and the spatial distribution. Also, it is possible to calibrate the system for the measurement of accurate absolute concentration. Firstly, the system was tested at a calibration chamber for the determination of scattering cross section from propane, butane, acetylene, Freon-12 and Genetron 143a. After this, the system was adapted to a steady flow rig to measure the temporal and spatial fuel concentration. The rig is composed of cylinder head, intake manifold, injector, and transparent cylinder which can simulate internal combustion engine. To cope with the interference of Mie scattering, which is main obstacle of the measuring concentration with Rayleigh scattering, a hardware filter was installed for reducing the number density of particles. Furthermore a software filter was developed, which is based on the rise time and the time constant of the photomultiplier-amplifier system. In addition, background noisy was reduced by adjusting the optical array and applying the pin hall and beam trap. The results show that LRS can provide useful information about concentration field and the software filter is very effective method to remove Mie interference.