• Title/Summary/Keyword: 경도 분포

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Inhomogeneous amplitude modulation effects on the MTF of binocular objective (비균일 진폭변조가 쌍안경 대물경의 MTF에 미치는 영향)

  • 홍경희
    • Korean Journal of Optics and Photonics
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    • v.10 no.2
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    • pp.102-106
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    • 1999
  • In this study, inhomogeneous amplitude modulation effects on the imaging performance a lens system are expermentally investigated by measuring the diffraction OTF. The lens under the test is a binocular objective made in Korea. Inhomogeneous amplitude modulation is carried out by positioning the modulator cross contacted to the lens under test which is illuminated by collimated light beam. The aberration characteristics of the lens under test are examined by caculating the ray-fan through finite ray tracing. The MTFs of the lens illuminated by the homogeneous and inhomogeneous light beam are measured on the Gaussian image plane and compared with one another.

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Correlation between Reverse Redistribution and Subendocardial Myocardial Infarction Observed in Myocardial Contrast Echocardiography (역재분포 소견과 심근조영 심초음파에서 보인 심내막하경색과의 관계)

  • Kim, Sung-Eun;Choe, Won-Sick;Kwan, Jun
    • The Korean Journal of Nuclear Medicine
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    • v.34 no.3
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    • pp.228-233
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    • 2000
  • Purpose: The aim of this study is to better understand the pattern and nature of reverse redistribution (RR) in myocardial perfusion imaging. Materials and Methods: In consecutive 20 acute myocardial infarction (MI) patients, frequency of RR was correlated with that of subendocardial MI that was detected by myocardial contrast echocardiography (MCE). RR was judged to be present when there was more than one grade of worsening in perfusion at 24 hr delayed images compared with the initial rest images. MCE evaluated the significant lack of opacification in the subendocardial myocardium relative to the subepicardial myocardium to suggest the subendocardial MI. Kendall's nonparametric correlation coefficiency was calculated. Results: Concordant cases were 15 of 20 (75%) and correlation was statistically significant (p=0.0285). Conclusion: Our results suggested that RR was correlated with MCE-detected nontransmural MI.

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Correlation between the Factors of Soil Physical Property in Upland Soil (밭작물 토양물리성 지표관련 인자의 상관분석)

  • Kim, Chan-Yong;Seo, Young-Jin;Kwon, Tae-Young;Park, Jun-Hong;Heo, Min-Soon;Ha, Sang-Keun
    • Korean Journal of Soil Science and Fertilizer
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    • v.43 no.6
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    • pp.793-797
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    • 2010
  • The investigations were conducted to improve the physical properties by analyzing physico-chemical properties on the different soil families of textures at 20 upland fields located in the parts of Gyengsangbuk-do area. Soil physico-chemical properties were analyzed for bulk density, hardness, porosity, moisture, pH, EC and organic mater by soil depth on the different soil families of textures. Bulk density distributions were higher than 1.2 Mg $m^{-3}$ in the optimum range. Hardness distributions were lower than 20 mm in the optimum range. Therefore, the physical properties of upland soil was deteriorated. Correlation coefficient of bulk density with hardness and organic mater were higher significantly, that was positive and negative, respectively. The soil hardness had the greatest distribution degree to the crop yield and bulk density and organic matter followed. Conclusively, To improve the physical properties of upland soil was more effective to fertilizing organic matter than other ways.

Microstructure and Hardness Distributions of $CO_2$ Lser Hrdened 12%-Cr Seel (12%-Cr 강의 $CO_2$ 레이저 표면경화에서 금속조직과 경도분포)

  • 김재도
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.16 no.10
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    • pp.1861-1868
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    • 1992
  • Laser beam hardening of 12%-Cr steel has been evaluated by using a continuous wave 3kW co$_{2}$ laser with a hardening mirror set. Experiment was performed on the hardening condition with a laser power of 2.85kW and travel speed of 1.0 and 1.5m/min. Multi passes have been also tried to find the hardening characteristics of partly overlapped zone. The black paint to use at high temperature was adopted to increase the absorptivity of laser beam energy with the wavelength of 10.6.mu.m at the surface of base metal. The microstructure of the hardened layers was observed by using a light microscopy, SEM and TEM. A fine Lamellar martensite formed in the hardened zones exhibits very high Vickers microhardness of 600Hv, whereas the tempered martensite distributes in the base metal with Vickers microhardness of 240Hv.It has been found that laser hardening with multi passes showed no significant drop of the hardness between adjacent passes.

A comparison of community structure and denitrifying ratio for denitrifying bacteria dependent on agricultural methods and seasons (농법과 계절에 따른 탈질세균의 군집 구조와 탈질율 비교)

  • Yoon, Jun-Beom;Park, Kyeong Ryang
    • Korean Journal of Microbiology
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    • v.53 no.1
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    • pp.9-19
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    • 2017
  • We studied soil composition, $N_2O$ production, a number of denitrifying bacteria, community structure and T-RFLP patterns of denitrifying bacteria dependent on agricultural methods with the change of seasons. Analyses of the soil chemical composition revealed that total carbon and total organic carbon contents were 1.57% and 1.28% in the organic farming soil, 1.52% and 1.24% in the emptiness farming soil, and 1.40% and 0.95% in traditional farming soil, respectively. So, the amount of organic carbon was relatively high in the environment friendly farming soils than traditional farming soils. In case of $N_2O$ production, the amount of $N_2O$ production was high in May and November soils, but the rate of $N_2O$ production was fast in August soil. The average number of denitrifying bacteria were $1.32{\times}10^4MPN{\cdot}g^{-1}$ in the organic farming soil, $1.17{\times}10^4MPN{\cdot}g^{-1}$ in the emptiness farming soil, and $6.29{\times}10^3MPN{\cdot}g^{-1}$ in the traditional farming soil. It was confirmed that the environment friendly farming soil have a larger number of denitrifying bacteria than the traditional farming soil. As a result of the phylogenetic analyses, it was confirmed that six clusters were included in organic farming soil among total 10 clusters. And the result of PCA profile distribution of T-RFLP pattern on agricultural methods, the range of distribution showed wide in the organic farming method, relatively narrow in the conventional farming method, and middle in the emptiness farming method. Therefore, we could concluded that the distribution and the community structure of denitrifying bacteria were changed according to the agricultural methods and seasons.

Effects of Soil Hardness on the Root Distribution of Pinus rigida Mill. Planted in Association with Sodding Works on the Denuded Land (사방시공지(砂防施工地)에 있어서 리기다소나무의 수근(樹根)의 분포(分布)에 미치는 토양견밀도(土壤堅密度)의 영향(影響))

  • Cho, Hi Doo
    • Journal of Korean Society of Forest Science
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    • v.56 no.1
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    • pp.66-76
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    • 1982
  • Soil harness represents such physical properties as porosity, amount of water, bulk density and soil texture. It is very important to know the mechanical properties of soil as well as the chemical in order to research the fundamental phenomena in the growth and the distribution of tree roots. The writer intended to grip soil hardness by soil layer and also to grasp the root distribution and the correlation between soil hardness and the root distribution of Pinus riguda Mill. planted on the denuded hillside with sooding works by soil layer on soil profile. The site investigated is situated at Peongchang-ri 13, Kocksung county, Chon-nam Province. The area is consisted of 3.63 ha having on elevation of 167.5-207.5 m. Soil texture is sandy loam and parant rock in granite. Average slope of the area is $17^{\circ}-30^{\circ}$. Soil moisture condition is dry. Main exposure of the area is NW or SW. The total number of plots investigated was 24 plots. It divided into two groups by direction each 12 plots in NW and SW and divided into three groups by the position of mountain plots in foot of mountain, in hillside, and in summit of mountain, respectively. Each sampling tree was selected as specimen by purposive sampling and soil profile was made at the downward distance of 50cm form the sampling tree at each plot. Soil hardness, soil layer surveying, root distribution of the tree and vegetation were measured and investigated at the each plot. The soil hardness measured by the Yamanaka Soil Hardness Tester in mm unit. the results are as follows: 1) Soil hardness increases gradually in conformity with the increment of soil depth. The average soil indicator hardness by soil layer are as follows: 14.6mm in I - soil layer (0-10cm in depth from soil surface), 16.2mm in II - soil layer (10-20cm), 17.2 in III - soil layer (20-30cm), 18.3mm in IV - soil layer(30-40cm), 19.8mm in V - soil layer (4.50mm). 2) The tree roots (less than 20mm in diameter) distribute more in the surface layer than in the subsoil layer and decrease gradually according to the increment of soil depth. The ratio of the root distribution can be illustrated by comparing with each of five soil layers from surface to subsoil layer as follows: I - soil layer; 31%, II - soil layer; 26%, III - soil layer; 18%, IV - soil layer; 12%, V - soil layer; 13%, 3) Soil hardness and tree root distribution (less than 20mm in diameter) of Pinus rigida Mill. correlate negatively each other; the more soil hardness increases, the most root distribution decreases. The correlation coefficients between soil hardness and distribution of tree roots by soil layer are as follows: I - soil layer; -0.3675 (at the 10% significance level), II - soil layer; -0.5299 (at the 1% significance level), III - soil layer; -0.5573 (at the 2% significance level), IV - soil layer; -0.6922 (at the 5% significance level), V - soil layer; -0.7325 (at the 2% significance level). 4) the most suitable range of soil hardness for the growth of Pinus rigida Mill is the range of 12-14.9mm in soil indicator hardness. In this range of soil indicator hardness, the root distribution of this tree amounts to 41.8% in spite of 33% in soil harness and under the 20.9mm of soil indicator hardness, the distribution amounts to 93.2% in spite of 82% in soil hardness. Judging from above facts, the roots of Pinus rigida can easily grow within the soil condition of 20.9mm in soil indicator hardness. 5) The soil layers are classified by their depths from the surface soil.

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Mixture distribution based nonstationary frequency model using climate variables (기후 변수를 이용한 혼합분포 기반 비정상성 빈도 모델)

  • Choi, Hong-Geun;Kim, Jang-Gyeong;Kwon, Hyun-Han
    • Proceedings of the Korea Water Resources Association Conference
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    • 2019.05a
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    • pp.338-338
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    • 2019
  • 설계강우량 산정시, 일반적으로 극치자료를 활용하여 정상성 가정하에 빈도해석을 수행하고 있다. 그러나 종종 정상성으로 가정했던 기존 극치강우자료가 정상성 빈도해석 모형에서 효과적으로 모델링되지 않는 비정상성 특성을 나타내고 있다. 또한, 대부분의 극치강우 분포는 해마다 다른 규모로 발생하는 홍수와 태풍 등의 강우요인으로 인해 두 개의 첨두를 갖는 혼합분포 형태를 보인다. 이에 본 연구에서는 혼합분포 기반 비정상성 빈도모델(mixture distribution based nonstationary frequency model, MDNF)을 제시하였다. 제안된 모형의 입력자료로 기후변수(e.g. SSTs and SLPs)를 사용하여 두 개의 분포형으로 구성되는 극치강우의 혼합비(mixing ratio)에 대한 영향을 분석하였으며, 극치강우 패턴이 특정 기후변수의 영향을 받는 것을 확인하였다. 최종적으로 Bayesian 기법을 MDNF 모형에 연계하여 각 첨두에 해당하는 분포형의 매개변수들에 대한 불확실성 구간을 정량적으로 제시하였다. 본 연구를 통해 강우 패턴의 변동은 설계 강우량 추정에 영향을 미치며, 특정 기후변수와 강우 패턴이 상관성을 가지는 것을 확인함으로써 합리적인 설계 강우량 산정을 위한 중요한 근거를 제공할 것으로 사료된다.

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Factors Affecting Distribution and Dispersal of Pomacea canaliculata in South Korea (왕우렁이(Pomacea canaliculata)의 국내 분포와 확산 특성 및 영향 요인 분석)

  • Lee, Dae-Seong;Park, Young-Seuk
    • Korean Journal of Ecology and Environment
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    • v.53 no.2
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    • pp.185-194
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    • 2020
  • Pomacea canaliculate (channeled apple snail; CAS), which is one of the world's worst alien invasive species, is widely distributed in Korea, and raised ecological and economic problems. In this study, we surveyed the distribution and dispersal characteristics of CAS in Korea, and analyzed the effects of environmental and anthropogenic (or social) factors on their distribution and dispersal. We considered various events related to CAS such as changes of policy including promotion of agriculture using CAS and enactment of biological diversity conservation law. Our results showed that human activities strongly influenced to the distribution and dispersal of CAS in Korea. Distribution of CAS seemed to relate with environment-friendly agriculture considering environmental conditions of CAS habitats. And dispersal characteristics of CAS were significantly correlated with social factors such as cultivation area and rate of organic products, production CAS on inland fishery.

Geochemical Implication of Rare Earth Element from Yellow sand (Asian Dust) at Daejeon Area, Korea: A Preliminary Study for Clarifying Source Area of Yellow Sand (대전지역 황사(아시아 먼지)내 희토류원소 분포도의 지구화학적 특성-근원지 규명을 위한 초기연구)

  • Lee, Seung-Gu;Youm, Seung-Jun
    • The Journal of the Petrological Society of Korea
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    • v.17 no.1
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    • pp.44-50
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    • 2008
  • A geochemical technique based on rare earth element geochemistry was used to clarity the source of the Asian dust (Yellow sand) in the Daejeon area. The Asian dusts were collected 4 times during 31th March- 2nd April and 25th May-27th May 2007. The Yellow sand shows PAAS (Post Archean Australian Shale)-normalized REE pattern of the flattened LREE and slightly depleted LREE without Eu anomaly, whereas the Daejeon soil has slightly enriched LREE and depleted HREE with negative Eu anomaly. Our results show that REE patterns of the Asian dust are LREE-flattened similar to those of the sediment from the south-eastern part of Ordos desert. This suggests that Asian dust in the Daejeon area might be derived from the south-eastern part of Ordos desert.

Soil Physical Properties of Arable Land by Land Use Across the Country (토지이용별 전국 농경지 토양물리적 특성)

  • Cho, H.R.;Zhang, Y.S.;Han, K.H.;Cho, H.J.;Ryu, J.H.;Jung, K.Y.;Cho, K.R.;Ro, A.S.;Lim, S.J.;Choi, S.C.;Lee, J.I.;Lee, W.K.;Ahn, B.K.;Kim, B.H.;Kim, C.Y.;Park, J.H.;Hyun, S.H.
    • Korean Journal of Soil Science and Fertilizer
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    • v.45 no.3
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    • pp.344-352
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    • 2012
  • Soil physical properties determine soil quality in aspect of root growth, infiltration, water and nutrient holding capacity. Although the monitoring of soil physical properties is important for sustainable agricultural production, there were few studies. This study was conducted to investigate the condition of soil physical properties of arable land according to land use across the country. The work was investigated on plastic film house soils, upland soils, orchard soils, and paddy soils from 2008 to 2011, including depth of topsoil, bulk density, hardness, soil texture, and organic matter. The average physical properties were following; In plastic film house soils, the depth of topsoil was 16.2 cm. For the topsoils, hardness was 9.0 mm, bulk density was 1.09 Mg $m^{-3}$, and organic matter content was 29.0 g $kg^{-1}$. For the subsoils, hardness was 19.8 mm, bulk density was 1.32 Mg $m^{-3}$, and organic matter content was 29.5 g $kg^{-1}$; In upland soils, depth of topsoil was 13.3 cm. For the topsoils, hardness was 11.3 mm, bulk density was 1.33 Mg $m^{-3}$, and organic matter content was 20.6 g $kg^{-1}$. For the subsoils, hardness was 18.8 mm, bulk density was 1.52 Mg $m^{-3}$, and organic matter content was 13.0 g $kg^{-1}$. Classified by the types of crop, soil physical properties were high value in a group of deep-rooted vegetables and a group of short-rooted vegetables soil, but low value in a group of leafy vegetables soil; In orchard soils, the depth of topsoil was 15.4 cm. For the topsoils, hardness was 16.1 mm, bulk density was 1.25 Mg $m^{-3}$, and organic matter content was 28.5 g $kg^{-1}$. For the subsoils, hardness was 19.8 mm, bulk density was 1.41 Mg $m^{-3}$, and organic matter content was 15.9 g $kg^{-1}$; In paddy soils, the depth of topsoil was 17.5 cm. For the topsoils, hardness was 15.3 mm, bulk density was 1.22 Mg $m^{-3}$, and organic matter content was 23.5 g $kg^{-1}$. For the subsoils, hardness was 20.3 mm, bulk density was 1.47 Mg $m^{-3}$, and organic matter content was 17.5 g $kg^{-1}$. The average of bulk density was plastic film house soils < paddy soils < orchard soils < upland soils in order, according to land use. The bulk density value of topsoils is mainly distributed in 1.0~1.25 Mg $m^{-3}$. The bulk density value of subsoils is mostly distributed in more than 1.50, 1.35~1.50, and 1.0~1.50 Mg $m^{-3}$ for upland and paddy soils, orchard soils, and plastic film house soils, respectively. Classified by soil textural family, there was lower bulk density in clayey soil, and higher bulk density in fine silty and sandy soil. Soil physical properties and distribution of topography were different classified by the types of land use and growing crops. Therefore, we need to consider the types of land use and crop for appropriate soil management.