• Journal of Korean Society of Forest Science
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• v.26 no.1
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• pp.13-18
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• 1975

This study was intended to clarify interrelations among seven characters of bamboo and their influences upon its culm-volume. The analysis of covariance was used to obtain phenotypic correlations, genotypic correlations and environmental correlations among some characters of Phyllostachys bambusoides Sieb. et Zucc., and thereby path-coefficients were calculated based on Dewey's method. The characters considered here included the breast height diameter, culm-height, clear-length, subterranean stem, number of bamboo joints, butt-end diameter and culm-volume of bamboo. Average values, standard errors, variances and standard deviations for the characters mentioned above are shown in Table 1, and phenotypic correlations, genotypic correlations and environmental correlations among seven characters are shown in Table 2, according to the results, there are highly significant relationships among lines but not among some replications. According to Table 4, heritability values in the breast height and butt-end diameters are higher than those in other characters mentioned above. On the other hand, environmental correlations among general characters appear to have lower values than phenotypic and genotypic correlations do. It also appears that the butt-end diameter and breast height diameter are highly correlated with the culm-volume of bamboo. The path-coefficients of individual characters to the culm-volume of bamboo are computed from the correlations (Table 4) and presented in Figure 1 and Table 5, where it could shown the direct and indirect effects on the bamboo culm-volume of each character.

• Journal of agriculture & life science
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• v.53 no.6
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• pp.23-33
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• 2019

In accordance with a change in the management information system containing the management record and planning for the entire national forest in South Korea by an amendment of the relevant law (The national forest management planning and methods, Korea Forest Service), in this study, average, the maximum, and the minimum values for DBH were presented while only average values were required before the amendment. In this regard, there is a need for an estimation algorithm by which all the existing values for DBH established before the revision can be converted to the highest and the lowest ones. The purpose of this study is to develop an estimation equation to automatically show the minimum and the maximum values for DBH for 12 main tree species from the data in the national forest management information system. In order to develop the estimation equation for the minimum and the maximum values for DBH, there was exploited the 6,858 fixed sample plots of the fifth and the sixth national forest inventory between in 2006 and 2015. Two estimation models were applied for DBH-tree age and DHB-tree height using such growth variables as DBH, tree age, and height, to draw the estimation equation for the maximum and the minimum values for DBH. The findings showed that the most suitable model to estimate the minimum and the maximum values for DBH was Dmin=a+bD+cH, Dmax=a+bD+cH with the variables of DBH and height. Based on these optimal models, the estimation equation was devised for the minimum and the maximum values for DBH for the 12 main tree species.

• Korean Journal of Crystallography
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• v.17 no.1
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• pp.14-18
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• 2006

MOCVD 공정방법에 의해 수직정렬된 ZnO 나노선을 합성하고 공정조건 제어에 의해 합성되는 나노선의 물리적, 광학적 특성이 어떻게 변화하는지를 고찰하고자 하였다. 온도 및 산소분압제어 등의 공전변수 제어를 통하여 ZnO 나노 구조체는 나노선, 나노로드 뿐만 아니라 나노바늘 (nano-needle) 등 다양한 구조로 변화되었으며 그 직경 및 길이도 제어가 가능하였다. 전체적으로 양호한 특성의 wurzite 구조를 나타내었으며 기판에 수직인 방향으로 [0001] 방향으로 성장하였다. 광학특성에서는 나노선 직경이 작아질수록 주방출 피크의 천이현상이 관찰되었다.

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.2
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• pp.136-143
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• 1997

직경 비가 0.56인 이중동심관에 내외측모두 매끈한 벽면, 벽면 거칠기를 안측, 외측, 그리고 양측 모두의 4경우에 대한 난류 유동과 열전달특성을 실험과 이론으로 연구하였다. 시간평균속도분포, 마찰계수, 그리고 최대 속도 지점과 전단응력이 0인 지점들을 피토튜브와 X형 열선 풍속계로 측정하였다. 이중동심관내에서 4가지 경우에 따른 사각돌출형 거칠기효과가 난류 유동과 열전달에 미치는 영향을 수정난류모델을 기초로 하여 연구하였다. 직경비, 거칠기 위치, 레이놀즈수, 그리고 프란틀수 등의 여러 변수에 의해서 난류 유동과 열전달을 고찰하였다. 본 연구는 전체적 효율 측면에서 유리하게 열전달율을 향상시킬수 있는 거칠기 구조를 밝혔다.

• Proceedings of the Korea Contents Association Conference
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• 2013.05a
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• pp.221-222
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• 2013

한국인 어린이 두피 모발에서 발견되는 서캐의 미세구조적 특징을 주사전자현미경으로 관찰하였다. 서캐는 길이가 약$800{\mu}m$로 무정형의 키틴질로 둘러싸여 있다. 서캐 케이스는 약 1mm의 모발을 키틴질로 완벽하게 둘러싸서 부착되어 있다. 서캐는 원추형으로 표면이 아주 매끄러우며 정단부에는 10개의 숨관으로 구성되어 있다. 숨관은 중앙에 3개의 숨관을 중심으로 7개의 숨관들이 둘러싸고 있다. 숨관 전체의 크기는 직경이 약 $160{\mu}m$로 원형의 형태를 하고 있다. 각각의 숨관은 직경이 $60{\mu}m$인 타원형의 돔모양으로 중앙에 약 $15{\mu}m$의 호흡통로가 열려 있다. 알이 부화된 후 분리된 뚜껑 단면에는 서캐의 안쪽에서 바깥쪽방향으로 약 $1{\mu}m$ 두께의 긴 홈이 일정하게 형성되어 있었다. 이와 같은 긴 홈은 알이 부화시 몸의 팽창으로 인한 키틴질 뚜껑의 분리를 용이하게 해주는 역할을 하는 것으로 확인하였다.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.1
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• pp.61-70
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• 2019

A primary investigation on the underexpanded flow generated in a 0.4 MW class high enthalpy supersonic arc-heated plasma wind tunnel is conducted experimentally. The diameter and the position of the Mach disk from the nozzle exit is measured for overall pressure ratios ranging from 200 to 30. The empirical correlations for Mach disk diameter and position are determined which show very good agreement with experimental results.

• Journal of the Korean Institute of Landscape Architecture
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• v.49 no.2
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• pp.27-40
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• 2021

This study was carried out for the description of the conflicts on the measurement of the root collar diameter of the landscape trees that are currently being produced, distributed, and planted in S. Korea, and for determination of the standard for root collar diameter measurement. The difference in consciousness of appropriate measurement of root collar diameter among different ages of landscape practitioners was statistically significant at p<0.05 level. It seemed to be due to the difference in the amount of field experiences among different age groups. On "the ambiguity of measuring the root collar diameter' of landscape trees", the consciousness was significantly different at p<0.05 level among job positions. On "Improvement of measurement criteria for landscape trees," it was significantly different at p<0.05 level among job types. This was thought to be due to the disagreement between the client and the contractor. On "prevention of topsoil removal" when excavating landscape trees, the consciousness was significantly different at p<0.001 level among different age groups, and different at p<0.01 level among different occupations, and different at p<0.05 level among different working area. The consciousness on "removing top soil when excavating landscape trees and rooting after transplantation" was not significantly different. The consciousness on the conflict caused by "ambiguity in root collar diameter measurement criteria" was high with an average of 3.85 for job type, occupation, jop position, and work experience. It was higher for landscape contractors than public institutions. The higher job positions and more experiences, the more conflicts. The consciousness on the appropriate position of root collar diameter measurement for landscape trees revealed that measuring at above-ground part (66.5%) was prefered to the underground part (33.0%). During the excavation of landscape trees for transplant, topsoil removal up to average depth of -2cm to -4cm was favored by 84.0%, and the purpose of removing topsoil was recognized as 'to increase the size and unit cost' by 59.7%.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.3
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• pp.502-509
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• 2003

After 800 students of Chonbuk National University was examined, 86 people (male : 43, female : 43, mean age : 22.2 years old) was selected as a group of normal occlusion. From their gypsum cast, this conclusion was obtained. 1. Intra-observer measurement errors in buccolingual diameter, maxillary lateral incisors have somewhat bigger errors. In mesiodistal diameter, maxillary first molars and maxillary second molar have bigger numerical value. Mean errors of measurement are 0.051mm at buccolingual diameter of crown and 0.083mm at mesiodistal diameter. 2. Fluctuating asymmetry is 0.030 average in buccolingual diameter, and 0.037 average in mesiodistal diameter. Statistically there are no big differences. 3. Male has longer buccolingual diameter than female in every permanent teeth. Teeth which have statistical difference in buccolingual diameter are maxillary lateral incisor, maxillary canine, maxillary second molar, mandibular central incisor, mandibular canine, mandibular second premolar, and mandibular first molar. In mesiodistal diameter maxillary central incisor, maxillary canine, and mandibular first molar have statistically difference. 4. Tooth which has the biggest difference depending on gender is maxillary lateral incisor in buccolingual diameter and mandibular canine in mesiodistal diameter. 5. Both sexes have similar crown index. Male has bigger value of crown module measurement and crown area measurement in every tooth. Crown area considered as size of tooth from occlusal surface was bigger in male than in female statistically except some teeth, maxillary first premolar, mandibular lateral incisor, first premolar and second premolar.

• Journal of Bio-Environment Control
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• v.22 no.2
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• pp.123-130
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• 2013

$CO_2$ enrichment systems have been recently used to shorten the growth period of plants and the improvement of harvest and its quality. To accomplish these goals, manifold should be designed to supply the same amount of $CO_2$. In this study, CFD approach has been used to understand the effects of geometric parameters, such as tube and hole diameters. An optimized geometry has been derived through pipe and tube part, respectively. As a result, the deviation of flow rate less than 0.1 g/s was expected at all holes of the $CO_2$ enrichment system.

• Journal of Korean Society of Forest Science
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• v.87 no.2
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• pp.173-178
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• 1998

Twelve Camellia sinensis populations were studied to investigate the biomass distribution related to stand structure. With increasing mean age of the population, mean root collar diameter increased, while mean height, density and root collar area had no correlation with the age. The result of dimension analysis after cutting the sample trees showed that dry weights of stems +branches and root were exponentially increased and dry weights of current leaves and twigs were linearly increased with increasing root collar diameter. However, the dry weight of older leaves was not related to the root collar diameter. The range of total biomass was 1,162~11,474kg/ha and the range of current leaf biomass was 165~1,341kg/ha. The range of T/R ratio was 1.5~2.8. The biomass of stems+branches and root were significantly correlated with the root collar area of the population and were not significantly correlated with the mean age, mean root collar diameter and density of the population. The biomass of current leaves and twigs were significantly correlated with the root collar area and density of the population.