• Journal of Dental Rehabilitation and Applied Science
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• v.29 no.4
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• pp.337-346
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• 2013

It is necessary to consider the median lingual foramen carefully to prevent the bleeding due to the damage of the sublingual artery for implant surgery. This study is to evaluate the frequency, location, diameter and the number of the Mandibular median lingual foramen regarding gender and age in the CBCT. Sixty two images of cone beam computed tomography (CBCT) whose visited the Chonnam National University Dental hospital from Sept. 2010 to Apr. 2011 were evaluated. Frequency, number, location and the diameter of Mandibular median lingual foramen shown in the CBCT image were evaluated. Sixty two patients (100%) had at least one median lingual foramen and fifty six patients (90.32%) had multiple foramens. Forty patients (66.13%) showed the median lingual foramen on the location between Mn. central incisors. The mean vertical position of the genial spine and the median lingual foramen was 24.21 mm and 14.52 mm, respectively. And the relative mean vertical dimension of median lingual foramen was 0.45. The mean diameter of the foramen was 0.93 mm. CBCT demonstrated the frequency, location, diameter and the number of median lingual foramen. It is necessary to take CBCT before implant placement to prevent the bleeding.

• Journal of Korea Foresty Energy
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• v.25 no.1
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• pp.31-38
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• 2006

Quercus mongolica is the most common hardwood species distributed in Korea. This study was conducted to investigate the biomass and energy content of the belowground biomass of Q. mongolica and to obtain the regression equation for estimating root biomass using the tree height and diameter at breast height (DBH). A total of 18 sample trees ranging 20 to 60 year-old were selected in the study sites. Tree height, DBH, age, and weight of stemwood, sapwood, heartwood, stembark, branch, leaf, and root were measured for total biomass. The highly positive correlation was shown between the biomass of most of variables of aboveground components and root biomass. The regression equation of the aboveground total biomass was $log\;W_A\;=\;1.469\;+\;0.992\;log\;D^2H\;(R^2 =0.99)$. The regression equation of the belowground biomass was $log\;W_R\;=\;1.527\;+\;0.808\;log\;D^2H\;(R^2\;=\;0.97)$. The mean energy contents of sapwood, heartwood, bark, leaf, and root were 19,594 J/g DW, 19,571 J/g DW, 19,999 J/g DW, 20,664 J/g DW, and 19,273 J/g DW, respectively. The results obtained from this study can be used to estimate biomass and energy content of belowground using easily measurable variables such as DBH and tree height ranging from 20 to 60-year-old Q. mongolica stands.

• Journal of Wetlands Research
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• v.25 no.3
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• pp.176-183
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• 2023

The aim of this paper is to understand the blade number effect on vortex turbine performance in the cylindrical vortex chamber below the free water surface. Using the same blade profile, the performance of gravitational vortex turbine is tested each with 2, 3, 4, 5 and 6 blades installed at the relative vortex height (y/h_v) ranging from 0.065 to 0.417. The obtained results indicate that the rotation, voltage, current and power increase in the relative vortex height of 0.065 and 0.111 when increasing the number of blades at flow velocity of less than 0.7 m/s. The average power of the 5-blade turbine is more than others. The performance of the 4-blade turbine with a 130 mm diameter installed near the orifice is higher than that of the same number of blades with a 220 mm diameter in the vortex chamber.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.2
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• pp.87-92
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• 2008

The breakup processes and spray plume characteristics of liquid jets injected in subsonic air cross-flows were experimentally studied. The behaviors of column, penetration, breakup of plain liquid jet and droplet sizes, velocities have been studied in non-swirling cross-flow of air. Nozzle has a 1.0 mm diameter and Lid ratio=5. Experimental results indicate that the breakup point is delayed by increasing air momentum, the penetration decreases by increasing Weber number and the split angle is increased by increasing air velocity or decreasing injection velocity. SMD increases according as increasing height or decreases in accordance with increasing air velocity. This phenomenon is related to the momentum exchange between column waves and cross-flow stream. Droplet vector velocities were varied from 11.5 to 33 m/s. A higher-velocity region can be identified in down edge region at Z/d=40, 70 and 100. Lower-velocity region were observed on bottom position of the spray plume.

• Journal of Korean Society of Forest Science
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• v.87 no.1
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• pp.90-97
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• 1998

This study was carried out to compare the characteristics of relative conductivity(RC) in the twenty-one deciduous broad-leaved species. The results obtained were summarized as follows : 1. The RC ranged from $3.18{\times}10^{-15}$ to $1.23{\times}10^{-10}m^2$ in deciduous broad-leaved species, and appeared different values in various portions of a tree and species. 2. In eight diffuse-porous species, the ranges of average RC were $3.49{\times}10^{-13}$ to $6.35{\times}10^{-11}m^2$ in stems. $4.89{\times}10^{-13}$ to $2.99{\times}10^{-11}m^2$ in branches, and $1.33{\times}10^{-13}$ to $9.42{\times}10^{-12}m^2$ in junction part between stem and branch. In thirteen ring-porous species, the RCs were $7.14{\times}10^{-13}$ to $4.76{\times}10^{-11}m^2$ in stems, $2.93{\times}10^{-13}$ to $3.91{\times}10^{-11}m^2$ in branches, and $1.14{\times}10^{-13}$ to $9.20{\times}10^{-12}m^2$ in junction part. 3. The RC and diameter of stem have no interrelation in eight diffuse-porous species. The RC of stem increased with decreasing diameter of stem in eleven ring-porous species except Fraxinus mandshurica and Maackia amurensis. 4. In five deciduous broad-leaved species, the RC of 1-year-old shoots(the leader and adjacent laterals ) ranged from $4.87{\times}10^{-13}$ to $8.41{\times}10^{-11}m^2$ in the leaders, and $7.93{\times}10^{-14}$ to $2.01{\times}10^{-11}m^2$ in the adjacent laterals. The RCs were much greater in the leaders than in the adjacent laterals because of the hydraulic dominance of the leader shoot.

• Journal of Korean Society of Forest Science
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• v.99 no.3
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• pp.391-396
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• 2010

To analyze the characteristics of canopy fuel in Pinus densiflora stand, which is essential to assess the crown fire hazard, allometric equations for estimation of crown fuel biomass were developed by subjectively categorized crown fuel component and crown bulk density was analyzed by available fuel component categories. Ten trees were destructively sampled at Pinus densiflora stand in Mt. Palgong in Daegu and their crown fuels were weighed separately for each fuel category by size classes and by living and dead. Regression equations that estimate crown fuel load by diameter at breast height(D) or additional total height(H) were derived. The adjusted coefficient of determination values were the highest (${R^2}_{adj}$=0.835-0.996) and standard error of estimate were the lowest (SEE=0.074-0.638) in the allometric equation lnWt=${\alpha}+{\beta}lnD+{\gamma}lnH$ in average. However, in needles and small branches categories, the differences in ${R^2}_{adj}$ and SEE between equations were not significant. Crown bulk density (CBD), which was calculated by crown fuel load divided by crown volume, was 0.067 kg/$m^3$ in average when only needles were considered as available crown fuel and 0.097 kg/$m^3$ when needles and branches (0-0.5 cm diameter) were considered. The increments of CBD of needles and small branches were little even when diameter at breast height increased.

• Journal of Korean Society of Forest Science
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• v.111 no.3
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• pp.394-404
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• 2022

This study was conducted to optimize the amount of drip irrigation for Prunus×yedoensis Matsum., one of the major medium-sized landscaping trees used mainly for streetscapes and as ornamentals. The experiment was conducted in a container nursery, where we assessed the growth and physiological characteristics of 4- and 8-year-old seedlings watered at different rates (x) by a drip irrigation system. The relative growth rates (based on height and root collar diameter (RCD) measurements) were highest at 288 and 416 L/year/tree for the 4- and 8-year-old containerized seedlings, respectively. These age and treatment combinations also produced significantly different dry weight and seedling quality index values, indicating good growth. The two age groups had significantly different total root lengths, root diameters, and root volumes under these respective irrigation treatments. In addition, the 4-year-old containerized seedlings irrigated at 288 L/year/tree and the 8-year-old containerized seedlings irrigated at 416 L/year/tree had the highest activations in their chlorophyll contents. Overall, the results (differences in irrigation amounts affect the seedlings morphological relative growth, biomass growth, seedling quality, and physiological reaction) indicate that the optimal irrigation amounts for container-grown Prunus×yedoensis are 288 L/year/tree for 4-year-old (RCD class, 3cm) and 416 L/year/tree for 8-year-old (RCD class, 7 cm) containerized seedlings.

• Journal of Bio-Environment Control
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• v.14 no.3
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• pp.160-165
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• 2005

Since the growth and quality of oak mushrooms are sensitively affected by environmental conditions, an adequate environmental control is very essential to improve the yield and quality under protected cultivation. In this study, the diameter, thickness, length and hardness of cap and stipe, the dry weight, fresh weight and moisture content of the mushrooms were analyzed under the environmental conditions such as night air temperatures (control, $5{\~}11^{\circ}C$ and $12{\~}18^{\circ}C$), relative humidities in the daytime (control, humidifying for 6 h and 12 h), and wind velocities (control, fan-operation for 6 h and 12 h). At a lower night temperature, the quality of the mushrooms was improved, and considered to be optimum at $3{\~}8^{\circ}C$ in terms of fresh weight and quality. At $70{\~}80{\%}$ of relative humidity in the daytime, the fresh weight was increased, but the quality decreased. Considering the quality, the relative humidity in the daytime is adequate at around $50{\%}$. At 6 h of maintaining the wind velocity at $1{\~}2\;my{\cdot}s^{-1}$, the growth and quality were better, but the lightness became higher at 12 h although the fresh weight was reduced by evaporation. It is concluded that even though both of the yield and quality are not easily improved at a same time, optimum approaches should be required by using the relationship among environmental factors and the growth and quality.

• Journal of the Korean Geotechnical Society
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• v.35 no.8
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• pp.17-30
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• 2019

Based on pile load test results for various pile types that were constructed in-situ and pile design data of prebored PHC piles, the ratio of skin friction to total capacity (SRF) was analyzed. A SRF distribution range from the pile load test results for pilot test prebored PHC piles was 42~99% regardless of relative penetration lengths, soil types, and pile load test types. However, a SRF distribution range from the pile design data for prebored PHC piles was 20~53% regardless of relative penetration lengths and pile diameters. Also, a SRF distribution range from the restrike dynamic pile load test results for pretest working prebored PHC piles was a scattered range of 4~83% regardless of pile diameters, relative penetration lengths and soil types. The scattered SRF of pretest working piles was caused to the quality control issue on the filling of cement milk around piles and this quality control issue should be improved. The average SRF calculated by the current design method was estimated to be 2.2 times lower than the average SRF of the pilot test piles. It is because skin friction resistance is calculated at a very low level. Therefore, a new design method for skin friction will be proposed based on this study.

• Journal of the Korean Wood Science and Technology
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• v.40 no.6
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• pp.378-388
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• 2012

This study was carried out to investigate the optimum condition for sap exudation of Juglans mandshurica in comparison with Acer mono Max. trees in a site of Inje-Gun, Gangwon-Do, Korea. Amount of sap exudation, air temperature, relative air humidity and tree diameter at breast height (DBH) were monitored for the period of February 1 through March 31, 2008, and correlation analysis of several factors affecting on sap exudation was carried out. Sap exudation from J. mandshurica initiated on Feb. 28 as the same time in case of A. mono and continued for a month, and enhanced in early March compared to around the middle of March for A. mono. The amount of sap of A. mono was linearly proportional to the diameter at breast height (DBH) but there was no apparent relationship for J. mandshurica. As the amount of sap exudation per tree increased then sap exudation per unit DBH was also linearly proportional in both J. mandshurica and A. mono. The amount of sap exudation per unit DBH of J. manshurica were $0.3{\pm}0.1{\ell}/cm$ on average, which was one third times of $0.9{\pm}0.1{\ell}/cm$ for A. mono. During the days of enhanced sap exudation, the atmospheric conditions such as air temperature and relative humidity around J. manshurica trees were very similar with those of A. mono. The minimum temperature was a significant factor affecting the amount of sap of J. mandshurica whereas the range of temperature was the principal factor for A. mono. In conclusion, the sap of J. mandshurica exudated in atmospheric conditions similar to A. mono, but the amount of sap was affected by different atmospheric factors compared to A. mono.