• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.3
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• pp.427-436
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• 2005

Topical application of APF gel can increase the surface roughness of resin composites and the roughened surfaces may allow increased bacterial accumulation and surface staining. Resin specimens of two proprietary resin composites, Filtek Z250(FZ) and Filtek Supreme Universal(FS), and experimental resin composites containing 0%, 3%, 6% nanofillers(E0, E3, E6) were fabricated and divided into two groups of the same number; APF treatment group and no treatment group. The amount of S. mutans adhered to specimens and the mean surface roughness(Ra) were measured. The results were as follows; 1. In no treatment group, the amount of S. mutans adhered to FS was the smallest. It was significantly different from those of FZ, E3, E6(p<0.05) although it was not significantly different from that of E0(p>0.05). 2. For all resin composites used, the amount of S. mutans adhesion in APF treatment group was significantly greater than that in no treatment group(p<0.05). 3. In APF treatment group, the amount of S. mutans adhesion was significantly different between materials(p<0.05), and increased in order of FS, FZ, E0, E3 and E6. 4. Difference of the surface roughness(Ra) between materials was not statistically significant in both no treatment group and APF treatment group(p>0.05)

• Journal of Cadastre & Land InformatiX
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• v.50 no.1
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• pp.163-180
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• 2020

In this study, to build a spatial information infrastructure, which is a component of a smart city, a 3D digital twin model in the downtown area was built based on the latest spatial information acquisition technology, the drone. Several analysis models were implemented by utilizing. While the data processing time and quality of the three types of drone photogrammetry software are different, the accuracy of the construction model is ± 0.04 in the N direction and ± 0.03m in the E direction. In the m and Z directions, ± 0.02m was found to be less than 0.1m, which is defined as the allowable range of surveying performance and inspection performance for the boundary point in the area where the registration of the boundary point registration is executed. 1: 500 to 1 of the aerial survey work regulation: The standard deviation, which is the error limit of the photographic reference point of the 600 scale, appeared within 0.14 cm, and it was found that the error limit of the large scale specified in the cadastral and aerial survey was satisfied. In addition, in order to increase the usability of smart city realization using a drone-based 3D urban digital twin model, the model built in this study was used to implement Prospect right analysis, landscape analysis, Right of light analysis, patrol route analysis, and fire suppression simulation training. Compared to the existing aerial photographic survey method, it was judged that the accuracy of the naked eye reading point is more accurate (about 10cm) than the existing aerial photographic survey, and it is possible to reduce the construction cost compared to the existing aerial photographic survey at a construction area of about 30㎢ or less.

• Korean Journal of Food Science and Technology
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• v.16 no.2
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• pp.235-241
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• 1984

Two fractions of pectinesterase from Chinese cabbage were isolated by ammonium sulfate fractionation, ion exchange chromatography on DEAE-cellulose and Sephadex G-150 gel filtration. The fraction F-A and F-B were purified approximately 340- and 10-fold. The similar salt effects and pH optima (pH 7.5-8.0) were obtained for the two pectinesterase fractions. The maximum activity of both two. fractions were obtained at 20-50mM of divalent rations and at 250mM of monovalent rations. The apparent Michaelis constant of the F-A was 0.01% for citrus pectin. The temperature optima for F-A and F-B were $48^{\circ}$ and $55^{\circ}C$, respectively and both fractions were stable in the region of pH 5.0-8.0 at room temperature. The thermal inactivation of the two fractions followed the first order reaction kinetics. From D and Z-values obtained the thermal resistance of the two fractions were characterized.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.36 no.4
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• pp.223-233
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• 2018

In this study was classified the cadastral control points and parcel boundary points into 40m, 100m by flight altitude of UAV (Unmanned Aerial Vehicle) which compared the coordinates extracted from the orthophoto with the parcel boundary point coordinates by GNSS (Global Navigation Satellite System) ground survey. As a results of this study, first, in the spatial resolution analysis that the average error of the orthoimage by flight altitude were 0.024m at 40m, and 0.034m at 100m which were higher 40m than 100m for spatial resolution of orthophotos and position accuracy. Second, in order to analyze the accuracy of image recognition by airmark of flight altitude that was divided into three cases of nothing, green, and red of RMSE (Root Mean Square Error) were X=0.039m, Y=0.019m and Z=0.055m, the highest accuracy. Third, the result of the comparison between orthophotos and field survey results that showed the total RMSE error of the cadastral control points were X=0.029m, Y=0.028m, H=0.051m, and the parcel boundary points were X=0.041m, Y=0.030m. In conclusion, based on the results of this study, it is expected that if the average error of flight altitude is limited to less than 0.05m in the legal regulations related to orthophotos for cadastral surveying, it will be an economical and efficient method for cadastral survey as well as spatial information acquisition.

• Korean Journal of Microbiology
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• v.52 no.2
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• pp.166-174
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• 2016

In order to find an efficient bacterial strain that can carry out nitrification and denitrification simultaneously, we isolated many heterotrophic nitrifying bacteria from wastewater treatment plant. One of isolates NS13 showed high removal rate of ammonium and was identified as Alcaligenes faecalis by analysis of its 16S rDNA sequence, carbon source utilization and fatty acids composition. This bacterium could remove over 99% of ammonium in a heterotrophic medium containing 140 mg/L of ammonium at pH 6-9, $25-37^{\circ}C$ and 0-4% of salt concentrations within 2 days. It showed even higher ammonium removal at higher initial ammonium concentration in the medium. A. faecalis NS13 could also reduce nitrate and nitrous oxide by nitrate reductase and nitrous oxide reductase, respectively, which was confirmed by detection of nitrate reductase gene, napA, and nitrous oxide reducase gene, nosZ, by PCR. One of metabolic intermediate of denitrification, $N_2O$ was detected from headspace of bacterial culture. Based on analysis of all nitrogen compounds in the bacterial culture, 42.8% of initial nitrogen seemed to be lost as nitrogen gas, and 46.4% of nitrogen was assimilated into bacterial biomass which can be removed as sludge in treatment processes. This bacterium was speculated to perform heterotrophic nitrification and aerobic denitrification simultaneously, and may be utilized for N removal in wastewater treatment processes.

• Korean Chemical Engineering Research
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• v.48 no.2
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• pp.244-252
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• 2010

The objective of this study is to assess feasibility of simultaneous analysis for trace multi-components odorous and volatile organic compounds using a Triple-bed adsorbent tube with a thermal desorber and GC-MS. Triple-bed adsorbent tube is 3 bed packed Tenax-TA with small amount of Carbopack B and Carbosieve SIII in order of adsorption strength in a tube. The operating conditions of GC-MS was possibly able to and effectively detect high volatile and low molecular weight compounds at the mass range of 20~350 m/z using a below impurity 1ppm of Helium carrier gas, of which quantitatively analyzed by target ion extracts. According to the experiment, $C_1{\sim}C_5$ of 14 components; sulfur containing compounds(2), ketones(2), alcohols(4) and aldehydes(6) were simultaneously analyzed with recoveries of 99%, and good repeatability and linearity. High volatile and low molecular weight compounds such as methyl alcohol and acetaldehyde can be safely quantified with high recovery at a condition of 50mL/min of flow rate, below 2L of adsorption volume, and 45% of relative humidity. Target ion extract can also simultaneously quantify multicomponents with odorous and volatile organic compounds in an occasion of piled up two peaks.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.1
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• pp.73-80
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• 2004

In this paper, the implementation and embedding method of the existing air-filled waveguide-filters at millimeter-wave on general PCB substrate is introduced by systematically inserting the vias inside waveguide and mathematically manipulating the simple equations obtained ken the classical circular-post waveguide filter design. All the metal structures placed vertically such as side wall fur perfect ground plane and circular-post for signal control in the air-filled WR-22 waveguide are replaced with several types of via for constructing the bandpass-filter. Side wall and poles inside waveguide are realized by placing a series array of via and tuning the via diameter. The lengths of x, y, z axis are reduced in proportion to root square of employed substrate dielectric constant and especially the length of z axis can be more reduced due to the characteristics of the wave propagation. Because the mass production on PCB is possible without fabricating a large-scaled metal waveguide of WR-22 as input/output ports at millimeter-wave regime, the manufacturing cost is reduced considerably. Finally, when using multilayer process like LTCC for small-sized module, it is one of advantages to use only one layer f3r the filter fabrication. To evaluate the validity of this novel technique, order-3 Chebyshev BPF(Bandpass-Filter) centered at 40 GHz-band with a 2.5 ％ FBW (Fractional Bandwidth) were used. The employed substrate has relative dielectric constant of 2.2 and thickness of 10 mil of Rogers RT/Duroid 5880. Accroding to design and measurement results, a good performance of insertion loss of 2 ㏈ and return loss of -30 ㏈ is achieved at full input/output ports.

• Journal of the Korean Wood Science and Technology
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• v.28 no.2
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• pp.32-41
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• 2000

Antimicrobial and antioxidative activities on heartwood extractives from Zelkova serrata were investigated to develop a natural fungicide or preservative. The ethanol extract from Z. serrata was fractionated in the order of petroleum ether, diethylether and ethylacetate to determine antimicrobial activity. The highest antimicrobial activity against the tested microorganisms was found in the petroleum ether soluble fraction. An active antimicrobial compound was isolated from petroleum ether soluble fraction, and identified as 7-hydroxy-3-methoxycadalene by $^1H$-, $^{13}C$-NMR and EI-MS spectrometry. This compound showed higher antifungal activity, but lower antibacterial activity than hinokitiol(${\beta}$-thujaplicin), strong antimicrobial compound isolated from Thujopsis dolabrata. Antioxidative activity was also higher than ${\alpha}$-tocopherol and similar to BHT(butylated hydroxytoluene), one of the strongest synthetic antioxidant. As a result, it was concluded that 7-hydroxy-3-methoxycadalene isolated from Z. serrata had strong antifungal and antioxidative activities.

• Korean Journal of Food Science and Technology
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• v.34 no.6
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• pp.1067-1072
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• 2002

Peroxidase was used as a standard enzyme to determine optimum blanching conditions of Flammulina velutipes and Lyophyllum ulmarium. Crude peroxidase extracted from raw mushrooms had maximum activity at $10{\sim}15^{\circ}C$ and pH 5.5 (50 mM, potassium phosphate buffer) using substrates of $H_2O_2$ and p-Phenylendiamine. Thermal inactivation of the crude peroxidase followed the first-order kinetics. The activation energy and z value of the crude peroxidase for F. velutipes were 59.58 kcal/mol and $9.0^{\circ}C$, whereas were 43.05 kcal/mol and $12.4^{\circ}C$ for L. ulmarium, respectively. On the basis of thermal kinetics parameters obtained, the optimum blanching conditions for F. velutipes and L. ulmarium were 1 min at $70^{\circ}C$ and 5 min at $80^{\circ}C$, respectively. Activation energies and z values of peroxidases extracted from heat-treated mushrooms were 7.97 and 6.55 kcal/mol, and $59.8^{\circ}C\;and\;74.1^{\circ}C$ for F. velutipes and L. ulmarium, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.1
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• pp.323-328
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• 2019

In order to construct 3D geospatial information about the terrain, current measurement using a total station, remote sensing, GNSS(Global Navigation Satellite System) have been used. However, ground survey and GNSS survey have time and economic disadvantages because they have to be surveyed directly in the field. In case of using aerial photographs and satellite images, these methods have the disadvantage that it is difficult to obtain the three-dimensional shape of the terrain. The terrestrial LiDAR can acquire 3D information of X, Y, Z coordinate and shape obtained by scanning innumerable laser pulses at densely spaced intervals on the surface of the object to be observed at high density, and the processing can also be automated. In this study, terrestrial LiDAR was used to analyze slope displacement. Study area slopes were selected and data were acquired using LiDAR in 2016 and 2017. Data processing has been used to generate slope cross section and slope data, and the overlay analysis of the generated data identifies slope displacements within 0.1 m and suggests the possibility of using slope LiDAR on land to manage slopes. If periodic data acquisition and analysis is performed in the future, the method using the terrestrial lidar will contribute to effective risk slope management.