• Journal of Ecology and Environment
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• 제42권4호
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• pp.155-162
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• 2018

Background: In ecosystem carbon cycle studies, distinguishing between $CO_2$ emitted by roots and by microbes remains very difficult because it is mixed before being released into the atmosphere. Currently, no method for quantifying root and microbial respiration is effective. Therefore, this study investigated the relationship between soil respiration and underground root biomass at varying distances from the tree and tested possibilities for measuring root and microbial respiration. Methods: Soil respiration was measured by the closed chamber method, in which acrylic collars were placed at regular intervals from the tree base. Measurements were made irregularly during one season, including high temperatures in summer and low temperatures in autumn; the soil's temperature and moisture content were also collected. After measurements, roots of each plot were collected, and their dry matter biomass measured to analyze relationships between root biomass and soil respiration. Results: Apart from root biomass, which affects soil's temperature and moisture, no other factors affecting soil respiration showed significant differences between measuring points. At each point, soil respiration showed clear seasonal variations and high exponential correlation with increasing soil temperatures. The root biomass decreased exponentially with increasing distance from the tree. The rate of soil respiration was also highly correlated exponentially with root biomass. Based on these results, the average rate of root respiration in the soil was estimated to be 34.4% (26.6~43.1%). Conclusions: In this study, attempts were made to differentiate the root respiration rate by analyzing the distribution of root biomass and resulting changes in soil respiration. As distance from the tree increased, root biomass and soil respiration values were shown to strongly decrease exponentially. Root biomass increased logarithmically with increases in soil respiration. In addition, soil respiration and underground root biomass were logarithmically related; the calculated root-breathing rate was around 44%. This study method is applicable for determining root and microbial respiration in forest ecosystem carbon cycle research. However, more data should be collected on the distribution of root biomass and the correlated soil respiration.

• Restorative Dentistry and Endodontics
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• 제20권1호
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• pp.55-70
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• 1995

Periapical lesions develop as a result of immunopathologic response to irritants from infected root canal systems. Removal of these irritants from the root canal system and sealing the root canal space may induce he31ing of the periapical lesions. 83 periapical lesions diagnosed as periapical abscess, periapical granuloma, chronic nonspecific inflammation, fibrosis and periapical Cyst were evaluated for the distribution of immunoglobulin containing cells. The influence of the state of root canal treatment on the distribution of immunoglobulin containing cells has evaluated. All lesions were divided into a group with no treatment, a group with canal enlargement, a group filled with gutta percha, and a group filled with Vitapex(calcium hydroxide). The distribution of immunoglobulin-containing cells according to the presence of pain and fistula was also evaluated. The following results were obtained. 1. Statistically significant difference in the distribution of immunoglobulin-containing cells among periapical abscess, periapical granuloma, chronic nonspecific inflammation/fibrosis and periapical cyst were found.(Kruskal-Wallis analysis, P<0.05) The number of immunoglobulin-containing cells in fibrosis was remarkably lower than that of periapical abscess, granuloma and cyst. 2. IgM and IgA containing cells were predominantly observed in periapical abscesses and periapical cysts, respectively. 3. All periapical lesions showed a large number of IgG containing cells followed by IgM, IgA and IgE containing cells. 4. There was a decrease in all Ig-containing cells in the group with canal filling compared to groups without treatment or with enlargement. That is, there is a decrease in Ig-containing cells as treatment progresses. 5. No significant correlation existed between the presence of pain and fistula and the distribution of immunoglobulin containing cells in periapical lesions.(t-test) Results appear to support that immune response are actively involved in the development and progress in periapical lesions. The fact that distribution of immunoglobulins differ according to the state of endodontic treatment suggests that root canal treatment may alter the humoral immune response of the periapical lesions.

• 한국음향학회지
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• 제21권3호
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• pp.304-309
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• 2002

LSP (Line Spectrum Pairs) 파라미터는 음성코덱 (codec)이나 인식기에서 음성신호를 분석하여 전송형이나 저장형 파라미터로 변환되어, 주로 저전송률 음성부호화기에 사용된다. 그러나 LPC (Linear Predictive Coding) 계수를 LSP로 변환하는 방법이 복잡하여 계산시간이 많이 소요된다는 단점이 있다. 기존의 LSP변환 방법 중 음성 부호화기에서 주로 사용하는 실근 (real root)방법은 근을 구하기 위해 주파수 영역을 순차적으로 검색하기 때문에 계산시간이 많이 소요되는 단점을 갖는다. 본 논문에서 기존의 실근 방법과 비교 평가한 알고리즘은 첫 번째 검색 대역에 멜 스케일 (met scale)을 사용하였고, 두 번째는 LSP 파라미터의 분포 특성을 조사하여 이를 토대로 검색구간의 순서와 검색간격을 달리 하였다. 실험결과, 기존의 실근 방식에 비하여 두 가지 방식 모두가 변환시간의 47% 이상이 감소되는데 반하여 동일한 근을 찾음을 알 수가 있었다.

• Journal of Forest and Environmental Science
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• 제10권1호
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• pp.8-24
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• 1994

수목(樹木)의 뿌리는 수목(樹木)의 생장(生長)과 토양(土壤)의 구조개선(構造改善)에 밀접한 관계가 있음에도 불구하고 지하부(地下部)에 위치하고 있으므로 연구가 미진한 상태이다. 따라서 각 수종(樹種)의 근계(根系)의 발달상태를 파악하는 것은 그 수종(樹種)의 특성 파악과 뿌리가 지표고정(地表固定)에 미치는 영향을 파악하는데 기초자료로 활용할 수 있다. 본 연구에서는 강원도(江原道) 소나무림(林)의 특성을 파악하기 위한 기초연구의 일부로서 일차적으로 강원대학교(江原大學校) 구내(構內) 소나무림(林)의 근계(根系) 형태(形態) 및 분포(分布)에 대하여 규명하였다. 5개의 공시목(供試木)에 대해 조사한 결과 뿌리의 형태(形態)는 수평근(水平根)이 잘 발달되어 있었다. 뿌리의 분포(分布)에 있어서 크기별로는 세근(細根)은 대부분이 점재(点在)(+)하고 있었음, 태근(太根)은 0.2cm가 대부분이었다. 깊이별로는 태근(太根), 세근(細根) 모두가 10~30cm에서 60~70% 이상 집중되었으며, 태근(太根)은 주로 0.9cm 이하였고, 세근(細根)은 대부분이 점재(点在)(+)하고 있었다.

• Journal of Advanced Marine Engineering and Technology
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• 제17권3호
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• pp.80-87
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• 1993

The various configuration of thin-shaped bevel gears are used usually for such as main reduction gear of the hovercraft. But the reasonable and concise guide to thedesign of the se bevel gears is not yet obtained, since the tooth of bevel gear has complex form. The purpose of these investigation is to be establish the design guide and to propose the desirable configuration form for thin-shaped straight bevel gear. In this report, the desirable configuration is examined experimentally by clearing up the effect of web and rim thickness, rim support condition upon the load distribution and root stress distribution along the tooth trace. The results are summarized as follows. (1) The crowning of tooth trace exerts a significant effect on the root stress distribution of thin-shaped bevel gear. (2) As the desirable configuration of the thin-shaped bevel gear, it is to be recommended that the rim is supported at the heel side of tooth trace. (3) But, as special type, it is desirable that the rim is supported at the toe side.

• 한국자동차공학회논문집
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• 제3권5호
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• pp.1-9
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• 1995

The purpose of this study is to develop a computer simulation program for analyzing load transmission characteristics of a helical gear system in design stage. In this analysis, the rotational delay, load distribution, root stress, and contact area are investigated. That is, the influence function of deflection is obtained by finite element analysis and the influence function of approach and gear tooth error are considered. Load distribution, rotational delay, and contact area are calculated by solving load-deflection equation which includes these influence functions and tooth error, and the influence function of the bending moment is obtained by finite element analysis. The root stress is calculated by the load distribution and the influence function of the bending moment. The results of the simulation are cross-checked through a specially designed experimental set-up.

• Journal of Ginseng Research
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• 제17권3호
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• pp.219-223
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• 1993

Assessment of root weight grade system for the numeral definition in Korea ginseng was tried by investigation of 13 boxes of the 15-root-grade of 4-year-old white ginseng as a model. In this case satisfaction to theoretical value was 58% in root weight and 50% in root number. The coefficient of variation (CV) was high (35%) for individual root weight in package. The CV of tap root weight 1 among package is low (7.1%) even though there was no significant correlation between tap root weight : and lateral root weight among roots. The mean percentage of tap root to root weight in each package ranged 61 to 74% with CV range of 16.5 to 33.2%. The CV was not much different between 1st and 2nd lateral root weight and the means was above 60%. Strict practice of numeral definition of root weight grade system will be prerequisite for chemical standardization of Korea ginseng.

• 한국약용작물학회지
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• 제7권3호
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• pp.177-184
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• 1999

자연교잡 실생 작약집단내에서 지상부 및 지하부에 관련하는 각형질의 특성과 분포를 조사한 결과는 다음과 같다. 자연교잡 실생 작약집단의 지상부생육은 맹아기가 4월 1일${\sim}$4월 15일, 경장은 $80.0{\sim}21.0cm$, 주당 경수는 $15{\sim}3$개로 분포가 다양하였다. 지하부의 근장은 $59{\sim}12cm$, 주당 근수는 $73{\sim}4$개였으며, 주당 약근 수량은 $882{\sim}37g$으로 개체간 변이가 심하였고 750g이상 되는 대형도 7.1% 분포하였다. Paeoniflorin함량은 $10.29{\sim}1.9%$로 7.5%이상의고 Paeoniflorin을 가진 개체도 14.3%분포하였다. 근장은 경직경과, 뿌리수량은 경장 및 뿌리직경과 각각 고도의 유의한 정의상관이 있었다.

• 한국작물학회지
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• 제44권1호
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• pp.20-25
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• 1999

This experiment was conducted to elucidate the relation-ship between vertical distribution of rice roots and yield traits under field conditions. Eight IRRI's new plant type rices (NPTRs) were tested in a volcanic ash soil paddy field under dense (IO 10 cm) and common (20 20 cm) planting densities. These lines were evaluated to have more spikelet numbers per panicle (SNP), lower filled grain rate (FGR), and lower rough grain weight per hill (RGWH). In dense planting, rough grain weight per stem (RGWS) was increased due to heavier culm and leaf dry weight (CLDW), and both RGWS and CLDW were related with the percentage of root distribution (%RWI) in the 10~30 cm soil layer, while in common planting, RGWS was not closely related with CLDW. SNP was highly related with root dry weight (RDW) in the 0~10cm soil layer. FGR was mainly affected by ROW in the 10~30 cm soil layer under both planting densities. RGWS was positively correlated with top dry weight (TDW) and harvest index (HI), and TDW was positively correlated with RWI under common planting or %RWI under dense planting, and HI was positively correlated with RWI in the 10~30 cm soil layer only under dense planting. RGWS was closely related with root weight index by dry weight (RWI) in the 10~30 cm soil layer and %RWI in the 0~30 cm or 10~30 cm soil layer under dense planting, and with only RWI in the 10~30 cm soil layer under common planting. But RGWH showed the close positive relationship with RDW and RWI in the 10~30 cm soil layer under dense planting, while under common planting, it showed the close positive relationship with RWI and %RWI in the 10~30 cm soil layer or %RWI in the 0~30 cm soil layer. The deeper root system in rice, especially under dense planting, is important for high yield of NPTRs focusing on the increment of top mass production and harvest index.

• Journal of the Korean Statistical Society
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• 제36권4호
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• pp.447-456
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• 2007

On the basis of marginal likelihood of the residual vector which is free of nuisance mean parameters, we propose new Lagrange Multiplier seasonal unit root tests in seasonal autoregressive process. The limiting null distribution of the tests is the standardized ${\chi}^2-distribution$. A Monte-Carlo simulation shows the new tests are more powerful than the tests based on the ordinary least squares (OLS) estimator, especially for large number of seasons and short time spans.