• Journal of Veterinary Clinics
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• v.16 no.2
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• pp.281-288
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• 1999

Helicobacter species have been identified in or isolated from domestic carnivores, but their prevalence in different population of animals and their clinical significance are still unknown. This study was peformed to evaluate the prevalence of Helicobacter in clinically healthy dogs by urease test, culture, morphological examination and polymerase chain reaction (PCR) technique. Tissue samples from 70 dogs in Kangwon and Kyunggi areas from August 1998 to April, 1999, were examined. The detection rates of Helicobacter by urease activity of tissue-samples were 84.6%, 61.3% and 4.8 % in the fundus, the antrum and the duodenum, respectively. One strain of Helicobacter was isolated from the duodenum. It was identified as H canis by biochemical and morphorogical examination. The detection rates of Helicobacter by histological examination were 92.3%, 79.0% and 4.8% in the fundus, antrum and the duodenum, respectively. Helicobacter organisms were colonized more in the gastric pits than in the surface of epithelium, the gastric gland or the parietal cell. Although most of dogs were colonized with Helicobacter in tissue, gross lesions and specific histopathological lesions caused by Helicobacter in these tissues were not observed. The detection rate of Helicobacter by PCR was 78.6%. The histological examination was more sensitive than urease test, culture or PCR technique for the detection of Helicobacter.

• Journal of the Korean Ceramic Society
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• v.35 no.5
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• pp.443-450
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• 1998

Layered double hydroxides(LDHs) [{{{{ {Mg }_{1-x } }}{{{{ {Al }_{x } }}({{{{ {OH}_{2 } }})]ζ+({{{{ {CO }`_{3 } ^{2- } ){ }_{x/2 } }}$.${{{{ { yH}_{2 }O }} wioth variation of layer charge densitywere synthesized by co-precipitation methdo since their charge densities have a very important role to be det-ermined the physicochemical properties of layered materials. The XRD IR and thermal studies of them were discussed and the kinetic study for the decarbonation reaction was also carried out. From the results of XRD analysis we found that the lattice parameter and the unit cell volume were linearly decreased with the amount of Al substituents(x) in the vicinity of x=2∼10${\times}$1/3${\times}$10-1 but they had nearly constant values when the x are far from these vicinit. The activation energies for the decarbonation reaction of x=6.8, 10${\times}$1/3${\times}${{{{ { 10}^{-1 } }} were estimated to be 47.0, 37.6, 39.3 kcal/mol The specific surface areas(90-120 m2/g) of stable hy-drotalcite-type LDHs were dractically decreased with increasing of layer charge density.

• Korean Journal of Materials Research
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• v.28 no.1
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• pp.50-61
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• 2018

Various carbon aerogels (CAs) were prepared from polymerization of resorcinol and formaldehyde and applied as the electrode materials of an electric double layer capacitor (EDLC) with the aim of controlling the textural and electrochemical properties of CAs by the type of base catalyst and the ratio of resorcinol to catalyst (R/C). The CAs from $NaHCO_3$ and $KHCO_3$ with $H^+$ ions had higher specific surface areas but exhibited lower electrochemical properties than those from $K_2CO_3$ and $Na_2CO_3$, which had more uniform pore size distributions. The electrochemical properties of $Na_2CO_3$ were superior to those of $K_2CO_3$ probably because the polarizing power of $Na^+$ ions was higher than $K^+$ ions. With an increasing R/C ratio, the pore sizes of CA showed a tendency to increase but the uniformity of the pore size distribution got worse. For the four base catalysts, the highest electrochemical property was obtained at the R/C ratio of 500.

• Journal of Environmental Impact Assessment
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• v.14 no.5
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• pp.317-335
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• 2005

This paper is primarily intended to propose a new concept of "aggregate control of road density" which is defined as the area-wide road surface per watershed area. An empirical study for experimental sites was conducted to confirm how a standard GIS technology can be used to assist in estimating the road density in terms of total volume threshold control. Guidelines for a replicable methodology are presented to provide a strong theoretical basis for the standardization of factors involved in the estimation of the road space threshold; the meaningful classification of road types, delination of watershed boundary, interpretation for distribution trends of road density etc. A variety of visual maps using overlay analysis can be generated over large areas quickly and easily to show the fact that some degree of road space already exists in the experimental sites. They could be used as an evidence to limit further construction of road network in comparison with other tributary watershed. It is anticipated that this research output could be used as a valuable reference to confirm the potential of introducing the new concept of "site specific road density" to support more scientific and objective decision-making in the process of road construction project.

• Journal of the Korean Ceramic Society
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• v.25 no.1
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• pp.59-65
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• 1988

To develop porous glass membranes used for a effective membrane-separation process, porous glasses and glass membranes were prepared from the sodium borosilicate parent glass by the phaseseparation technique and effects of heat-treatment and leaching conditions on their characteristics were investigated. The crack-free glass membranes could be fabricated from the 9.4 Na2-O-30.7 B2O3-59.2 SiO2-0.7 Al2O3(wt%) parent glass by heat-treatment at the lower temperature(550-570$^{\circ}C$) and for longer than 45 hrs for the phase separation, followed by leaching with 3N-HCl＋60% ethylene glycol solution at 90$^{\circ}C$ over 25 hrs. Porous glasses prepared in this work showed large specific surface areas(400㎡/g) and narrow pore size distribution with the mean pore radius of 14${\AA}$ enough for the application as reverse osmosis membranes. The salt-rejection efficiency and product-flux of the glass membranes heat-treated at 570$^{\circ}C$ for 80 hrs were found to be 51.8% and 270cc/㎡. hr, respectively. This result suggests that the porous glass membranes fabricated in this study could be applied for the reverse osmosis process.

• Journal of the Korean Ceramic Society
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• v.39 no.7
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• pp.617-621
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• 2002

Calcium aluminosulfate (3CaO.3Al$_2$O$_3$.CaSO$_4$or $C_4$A$_3$S) was prepared by chemical synthesis from the nitrate salts and aluminum sulfate. $C_4$A$_3$S was the main phase after calcination at 110$0^{\circ}C$. The specific surface areas after calcination at 110$0^{\circ}C$ and 130$0^{\circ}C$ were about 2.5 and 1.0 $m^2$/g, respectively. Hydration was investigated by XRD, DSC, SEM, EDS, conduction calorimetry and analysis of the liquid phase. Calorimetry showed that the induction period was longer than that of a sample prepared by conventional solid state sintering and this was attributed to the formation of amorphous coatings in abundance of $Al_2$O$_3$ and SO$_3$. Crystalline hydration products, principally calcium monosulfoaluminate hydrate and Al(OH)$_3$, appeared subsequently.

• Carbon letters
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• v.5 no.2
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• pp.81-87
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• 2004

The effect of compositions of $Al_2O_3$ in the mixed $Fe/Al_2O_3$ catalysts on the synthetic behaviors of carbon nanotubes (CNTs) by catalytic chemical vapor deposition (CCVD) process was investigated in wide range of the mixture ratios of support materials. CNTs were synthesized with $Fe/Al_2O_3$ catalysis under the condition of 40 min in synthetic time, and 923 K of synthetic temperature using $C_2H_4$ and $H_2$ as synthetic and carrier gas, respectively. The carbon yield with the content of $Al_2O_3$ showed in a parabolic curve and the maximum carbon yield was 40 wt.% of $Al_2O_3$. As the mixture ratio of $Al_2O_3$ increased, decreasing tendency was observed in the diameter of CNTs. Specific surface areas of CNTs were increased with the increase of the mixture ratio of $Al_2O_3$.

• The Journal of the Korean dental association
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• v.9 no.12
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• pp.791-795
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• 1971

Thirty-four children who were patients at the Pedodontic Department of Infirmary of Dental College, S.N.U., aged from 3 years 1 month to 6 years 10 months. One quadrant jaw was measured for each child, Each of the 5 teeth was measured in 6 specific areas, therefore, a total of 1,020 measurements were observed. The results were as follows: 1. Facial surface was the shallowest of all. It was 0.14 mm. shallower than lingual, 0.62mm. shallower than mesial, 0.98mm. shallower than distal. 2. The sulcus generally increased in depth from anterior to posterior. 3. The anterior segment in the maxilla was the shallowest of all. It was 0.68mm. shallower than posterior of maxilla, 0.08 mm. shallower than anterior of mandible, 0.63 mm. shallower than posterior of mandible. 4. The most frequent measurement observed in the both jws was 1.4mm. 5. The mean for the complete anterior segment in the maxilla was 1.3±0.50 mm. In the posterior segment of the maxilla, the mean was 2.0v0.74mm. In the mandible, the mean for the anterior segment was 1.4±0.46 mm. In the posterior segment of the mandible, the mean was 2.0±0.56 mm. 6. The mean gingival sulcus depth for the entire Primary Dentition was 1.7±0.59 mm.

• Environmental Engineering Research
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• v.19 no.3
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• pp.215-221
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• 2014

Nano-sized $TiO_2$ particles were produced by a premixed flame aerosol reactor, and they were immobilized on a mesh-type substrate in form of particulate film. The reactor made it possible maintaining the original particulate characteristics determined in the flame synthetic process. The particulate morphology and crystalline phase were not changed until the particulate were finally coated on the substrate, which resulted in the better performance of the photocatalytic conversion of the volatile organic compounds (VOCs) in the ultraviolet $(UV)-TiO_2$ system. In the flame aerosol reactor, the various specific surface areas and the anatase weight fractions of the synthesized particles were obtained by manipulating the parameters in the combustion process. The performance of the $TiO_2$ particulate films was evaluated for the destruction of the VOCs under the various UV irradiation conditions. The decomposition rates of benzene and formaldehyde under the irradiation of UV-C of 254 nm in wavelength were evaluated to check the performance of $TiO_2$ film layer to be applied in air quality control system.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.744-746
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• 2003

A 3D modeling of urban area can be composed the terrain modeling that can express specific and shape of the terrain and the object modeling such as buildings, trees and facilities which are found in urban areas. Especially in a 3D modeling of building, it is very important to make a unit model by simplifying 3D structure and to take a texture mapping, which can help visualize surface information. In this study, the texture mapping technique, based on library for 3D urban modeling, was used for building modeling. This technique applies the texture map in the form of library which is constructed as building types, and then take mapping to the 3D building frame. For effectively apply, this technique, we classified buildings automatically using LiDAR data and made 3D frame using LiDAR and digital map. To express the realistic building texture, we made the texture library using real building photograph.