• Journal of Periodontal and Implant Science
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• v.24 no.1
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• pp.165-177
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• 1994

To investigate the depth of the root concavity and root surface area of the maxillary first premolar, 40 maxillary first premolars were used. All the teeth which extracted because of advanced periodontal disease and orthodontic treatment procedure, were sectioned every 1.5mm from cementoenameljunction to the apex with hard tissue microtome. Each sectioned root was taken photograph with slide film, and projected for measuring with a calibrated digital Curvi-Meter. The root surface area, percentage of the RSA and the linear variation of the RSA were calibrated for each 1.5mm section. Linear variation of the depth of root concavity was measured on mesial and distal root surface for each section using computer-aided digitizer. The results were as follows. 1. The total mean root length of maxillary first premolar was 13.48mm. Mean buccal root length of 2-rooted tooth was 12.59mm, mean palatal root length was 12.73mm, and mean root length of single rooted tooth was 13.78mm. 2. The total mean root surface area of maxillary first premolar was $194.17mm^2$, mean root surface area for 2-rooted tooth was $205.97mm^2$ and mean root surface area for single rooted tooth was $188.49mm^2$. 3. It was 59.93% of the total root surface area that the area from CEJ to coronal 6mm. And, the coronal half of the root length accounted for approximately 71.76% of the total root surface area. 4. Most deepest concavity of the mesial root surface was 0.65mm at apical 3.0mm, 4.5mm level in maxillary first premolar. And, that of the distal root surface was 0.37mm at apical 4.5mm level. 5. All of the maxillary first premolar had mesial root surface concavity. This mesial root surface concavity appeared to be more pronounced in 2-rooted tooth than single rooted tooth.

• Journal of Korean Society of Water and Wastewater
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• v.35 no.2
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• pp.163-174
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• 2021

Heatwaves are one of the most common phenomena originating from changes in the urban thermal environment. They are caused mainly by the evapotranspiration decrease of surface impermeable areas from increases in temperature and reflected heat, leading to a dry urban environment that can deteriorate aspects of everyday life. This study aimed to calculate daily maximum ground surface temperature affecting heatwaves, to quantify the effects of urban thermal environment control through water cycle restoration while validating its feasibility. The maximum surface temperature regression equation according to the impermeable area ratios of urban land cover types was derived. The estimated values from daily maximum ground surface temperature regression equation were compared with actual measured values to validate the calculation method's feasibility. The land cover classification and derivation of specific parameters were conducted by classifying land cover into buildings, roads, rivers, and lands. Detailed parameters were classified by the river area ratio, land impermeable area ratio, and green area ratio of each land-cover type, with the exception of the rivers, to derive the maximum surface temperature regression equation of each land cover type. The regression equation feasibility assessment showed that the estimated maximum surface temperature values were within the level of significance. The maximum surface temperature decreased by 0.0450℃ when the green area ratio increased by 1% and increased by 0.0321℃ when the impermeable area ratio increased by 1%. It was determined that the surface reduction effect through increases in the green area ratio was 29% higher than the increasing effect of surface temperature due to the impermeable land ratio.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.1457-1459
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• 2003

This study reports the surface temperature pattern of the Tokyo Metropolitan area using the ASTER surface temperature product. The product is an image processed by applying temperature-emissivity separation to atmospheric corrected infrared thermal radiance of the land surface, then converted to surface temperature by using Planck's function. Daytime and nighttime observation in a cold season and a warm season were used in this study. As a result, 1) contrast between urban and suburban, 2) extraction of heating area in urban, 3) measurement of cooling effect of green space were achieved.

• Microbiology and Biotechnology Letters
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• v.40 no.2
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• pp.157-162
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• 2012

In this study, we have for the first time applied increased surface area fractional precipitation in order to decrease the particle size of the anticancer agent paclitaxel from plant cell cultures. When compared with the case where no surface area increasing material was employed, the addition of ion exchange resin as a surface area increasing material resulted in a considerable decrease in the size of the paclitaxel precipitate. When ion exchange resin was used, the paclitaxel particles were four to five times smaller, having less than a 20 ${\mu}m$ radius, than those obtained in the absence of ion exchange resin. This is presumably because the growth of paclitaxel particles was impeded by the addition of ion exchange resin. The size of the paclitaxel precipitate also depended on the material used to increase the surface area, a result considered to be due to differences in the affinity between the particular ion exchange resin used and the paclitaxel particles. The yield of paclitaxel was significantly improved when ion exchange resin was used as a material to increase surface area. Paclitaxel, with a reduced particle size due to the addition of a surface area increasing material during the fractional precipitation process, is believed to be particularly useful for practical applications of the drug.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.387-392
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• 2005

The research was performed to predict the potential landslide with roughness index. It was known that fractal dimension and surface area index can be represented the topography, specially when the natural slopes were rough or rugged. A test site was selected and fractal dimension and surface area index were calculated from the irregular triangle network. Fractal dimension were ranged between $2.016{\sim}2.046$ and surface area index $1.56E+07{\sim}2.59E+07$. Surface area index increased as fractal dimension increased. Slope stability was calculated by infinite slope stability analysis model and was compared to slope stability by fractal and surface area index. In the result, unsafe zones where slope stability is under 1.1 were $5.11{\sim}6.25%$ for the test site. It can be said that fractal dimension and surface area index are a good index to evaluate the slope stability because when fractal dimension and surface area index are greater, then stability of the site is more unsafe.

• Nuclear Engineering and Technology
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• v.25 no.4
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• pp.507-514
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• 1993

Titanium tubes have recently been used in condensers of nuclear power plants since titanium has very good corrosion resistance to seawater. However, when it is connected to Cu alloys as tube sheet materials and these Cu alloys are connected to carbon steels as water box materials, it makes significant galvanic corrosion on connected materials. It is expected from electrochemical tests that the corrosion rate of carbon steel will increase when it is galvanically coupled with Ti or Cu in sea water and the corrosion rate of Cu will increase when it is coupled with Ti, if this couple is exposed to sea water for a long time. It is also expected that the surface area ratios, R$_1$(surface area of carbon steel/surface area of Ti) and R$_2$(surface area of carbon steel/surface area of Cu) are very important for the galvanic corrosion of carbon steel and that these should not be kept to low values in order to minimize the galvanic corrosion on the carbon steel of the water box. Immersed galvanic corrosion tests show that the corrosion rate of carbon steel is 4.4 mpy when the ratio of surface area of Fe/ surface area of Al Brass is 1 while it is 570 mpy when this ratio is 10$^{-2}$ . The galvanic corrosion rate of this carbon steel is increased from 4.4 mpy to 13 mpy at this area ratio, 1, when this connected galvanic specimen is galvanically coupled with a Ti tube. This can be rationalized by the combined effects of R$_1$ and R$_2$ on the polarization curve.

• Water for future
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• v.29 no.2
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• pp.143-151
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• 1996

The dynamic responses in the subsurface outflow, surface saturation area, soil moisture storage are established by numerical experiments with Richards equation. In addition to this, the dynamical relationship between surface saturation area and subsurface outflow, and between surface saturation area and soil moisture storage are also determined by varying the hillslope shape, soil type, and boundary condition. The simulation results indicate that the dynamical relationships between surface saturation area and subsurface outflow, and between surface saturation area and soil moisture storage are approximated by the steadystate relationships. And the dynamic responses of subsurface outflow and surface saturation area are characterized by the double peaks although the rainfall pattern is asimple pulse input. As a result of numerical simulation, the physical mechanism for the occurrence of the double peaks is explained using the concept of variable source area.

• Journal of Periodontal and Implant Science
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• v.23 no.1
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• pp.159-169
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• 1993

The thirty six mandibular second molars, which were extracted because of hopeless tooth due to advanced periodontal disease, were measured the length of mesial and distal root and the distance from cementoenamel junction to root separation. The molars were cross-sectioned every 1.5 milimeter from cementoenamel junction to root apex perpendicular to long axis and each section was photographed, projected and measured with a calibrated Digital Curvi-Meter(Com Curvi-8. Japan). The root surface area (RSA), percentage of the RSA and the linear variation of the RSA were calibrated for each 1. 5 mm section. The results were as follows. 1. The mean length of the roots was 12. 98mm for mesial root, 11.84 mm for distal root. The mesial root was longer than distal root.(p<0.01) 2. The mean distance from the cementoenamel junction to the point at which the root separate from the root trunk was 3.82mm for the buccal furcation and 4.75mm for lingual furcation. The buccal root separation was coronal than the lingual root separation.(p<0.01) 3. The total root surface area was $317.78mm^2$. 4. The mean surface area of the root trunk was $150.06mm^2$ and averaged 42.54% of the total root surface area. 5. The mean root surface area was $88.79\;mm^2$ for the mesial root, $78.93mm^2$ for distal root, The mesial root surface area was wider than the distal root surface area.(p<0.05) 6. In comparision, the mean root trunk surface area of the mandibular 2nd molar was wider than that of mandibular 1st molar(p<0.01), but each root of 2nd molar was smaller than that of 1st molar(p<0.01).

• Journal of the Korean Society of Environmental Restoration Technology
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• v.4 no.3
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• pp.1-9
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• 2001

The purpose of this study was to evaluate the burning impacts of the surface and crown fire occured in yongsan-ri meongsok-myun of chinju-city, Gyeongnam. Environmental influences like surface runoff and soil erosion changes were investigated by comparisons analysis between burned and unburned area about some initial effects after fire. The results obtained from this study were as followed; 1. The average amount of surface runoff in burned area was more 1.7 times than in unburned area. But it was gradually tend to decrease in burned area as times passed. 2. Factors significantly correlated to amount of surface runoff in burned area shown in order to unit rainfall, accumulated rainfall and sand content, as 0.9466 of multiple correlation coefficient, where as the factors in unburned area were unit rainfall, soil erosion, bulk density and soil hardness, as 0.9738 of multiple correlation coefficient. 3. The average amount of soil erosion in burned area was more 11.2 times than in unburned area. But it was gradually tend to decrease in burned area as times passed. 4. Factors significantly correlated to amount of soil erosion in burned area were surface runoff and unit rainfall, as 0.6305 of multiple correlation coefficient. The factors in unburned area shown in order to surface runoff, sand content, bulk density and unit rainfall, as 0.7879 of multiple correlation coefficient.

• Journal of the Mineralogical Society of Korea
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• v.11 no.2
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• pp.126-134
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• 1998

Surface site and areas of particles are geometrically calculated for the cubic structures to investigate how the surface sites vary with the variation of morphology and particle size. The numbers of surface site and area become smaller when the particles become equi-dimensional shape. The ratios of surface site to surface area are almost constant except the case of anion of fluorite structure. The ratios of the number of surface site to area are almost constant regardless of particle size except the size of up to 5 to 10 times of the unit cell dimension. This quantification method can be used to obtain data related to the surface reaction.