• Journal of the Korean Society of Radiology
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• v.1 no.1
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• pp.11-16
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• 2007

In this study, we have performed contrast-detail analysis for an amorphous selenium(a-Se) based digital X-ray imaging system by using a contrast-detail phantom(CDRAD 2.0) to test its low contrast performance. The X-ray imaging system utilizes an 500-mm-thick a-Se semiconductor X-ray absorber coated over an amorphous silicon(a-Si) TFT(thin-film transistor) detector matrix with a $139mm{\times}139mm$ pixel size and a $46.7cm{\times}46.7cm$ active area. In the measurement of contrast-detail curves we first acquired X-ray images of the CDRAD 2.0 phantom at given test conditions(i.e., 40, 50, 60, 70, 80 kVp, and 16 mA.s), and then evaluated the contrast-detail characteristics of the imaging system from each phantom image by using an image quality factor called the image-quality-figure-inverse(IQFinv). The IQFinv values for the imaging system gradually improved with the photon fluence, indicating the improvement of image visibility: 24.4, 35.3, 39.2, 41.5, and 43.4 at photon fluences of $1.8{\times}105$, $5.9{\times}105$, $11.3{\times}105$, $19.4{\times}105$, and $29.4{\times}105$ photons/$mm^2$, respectively.

• Journal of Mushroom
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• v.11 no.4
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• pp.249-253
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• 2013

'Gonji10ho', a new variety of Neolentinus lepideus, was bred by mating two monokaryotic strains isolated from 'GMNL66037' and 'GMNL66014' in Mushroom Research Institute, Gyonggi-Do ARES in 2012. The optimum temperature for the mycelial growth of 'Gonji10ho' was $29^{\circ}C$ on PDA medium and that for the primordia formation and the growth of fruiting body of 'Gonji10ho' was $20{\pm}1^{\circ}C$. In bottle cultivation of 'Gonji10ho', the period of spawn running was around 35 days at $22{\pm}1^{\circ}C$ and the period from scratching of inoculum to harvesting was 27 days. 'Gonji10ho' had thicker pileus and stipe than control variety('Solhyang'). The number of available stipe was fewer than that of control variety. During the cultivation of 'Conji10ho', the occurrence rate of Trichoderma spp. was lower than that in control variety. In bottle cultivation, the yield of fruiting bodies of 'Gonji10ho', which was 38% higher than that of control variety, was 69.6 g/900 ml bottle, and in bag cultivation, that of 'Gonji10ho', which was 10% higher than that of control variety, was 114.2 g/1 kg bag. In physical characteristics, the strongness and brittleness of the pileus of 'Gonji10ho' were higher than those of control variety. When considered in the period available for sale, the shelf life of 'Gonji10ho', which was 5 days longer than that of control variety, was 34 days.

• Korean Journal of Food Science and Technology
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• v.28 no.2
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• pp.324-329
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• 1996

In order to develop a novel dewatering process for soybean milk residue, hydraulic press with ohmic heating was built and its expression conditions were examined. The electric conductivity of raw soybean milk residue was 0.128 S/m and increased linearly with increasing temperature. Water content of the residue could be reduced to 74% with the conventional hydraulic press, but to less than 70% by applying ohmic heating to the hydraulic press. The most effective dewatering was achieved by applying alternative current with 5 kHz frequency at 60 V during expression. The solid content of the expressed liauid was markedly reduced from 10% to 3.3% by ohmic heating during expression. Temperature of the cake rose to above $95^{\circ}C$ during the dewatering due to ohmic heating.

• Journal of Radiation Protection and Research
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• v.29 no.2
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• pp.97-104
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• 2004

MIRD-type Korean adult male phantom, 'KMIRD' was constructed to calculate Korean-specific dosimetric quantities for radiation protection consideration. The external shape of KMIRD was based on national physical standard data of Korean. KMIRD has thicket trunk than MIRD5 and arm models divided from trunk. The height and weight of the KMIRD are 171 cm and 63.8 kg. ICRP23 data were referred to constitute organs and tissues of KMIRD. However nine organs were constructed based on Korean reference data provided by Radiation Health Research Institute. In the present study, the MCNPX2.3 Monte Carlo transport code was combined with KMIRD to calculate dose conversion coefficients for photon in the energy range from 0.05 to 10 MeV. The simulated irradiation geometries are broad parallel photon beams in AP, PA, LLAT and RLAT direction. Absorbed dose conversion coefficients were compared with data calculated with MIRD5, MIRD-type phantom based on ICRP23 reference man. In some organs, the discrepancies between two phantoms amount up to nearly 30%. The effective doses conversion coefficients of KMIRD are lower than those of MIRD5. The dose discrepancies between two MIRD-type phantoms ate because of physical differences between Korean and Western, also geometric differences between two phantoms. KMIRD should be revised using the full set of Korean reference data of all organs. The developed MIRD-type Korean adult male phantom can be applied to dose assessment of internal exposure.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.16 no.4
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• pp.419-429
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• 2003

A three-dimensional (3-D) method of analysis is presented for determining the free vibration frequencies of thick, hyperboloidal shells of revolution. Unlike conventional shell theories, which are mathematically two-dimensional (2-D), the present method is based upon the 3-D dynamic equations of elasticity. Displacement components u/sub r/, u/sub θ/, u/sub z/ in the radial, circumferential, and axial directions, respectively, we taken to be sinusoidal in time, periodic in θ, and algebraic polynomials in the r and z directions. Potential(strain) and kinetic energies of the hyperboloidal shells are formulated, and the Ritz method is used to solve the eigenvalue problem, thus yielding upper bound values of the frequencies by minimizing the frequencies. As the degree of the polynomials is increased, frequencies converge to the exact values. Convergence to four digit exactitude is demonstrated for the first five frequencies of the hyperboloidal shells of revolution. Numerical results are tabulated for eighteen configurations of completely free hyperboloidal shells of revolution having two different shell thickness ratios, three variant axis ratios, and three types of shell height ratios. Poisson's ratio (ν) is fixed at 0.3. Comparisons we made among the frequencies for these hyperboloidal shells and ones which ate cylindrical or nearly cylindrical( small meridional curvature. ) The method is applicable to thin hyperboloidal shells, as well as thick and very thick ones.

• Korean Journal of Plant Taxonomy
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• v.40 no.3
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• pp.135-144
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• 2010

This study intended to investigate environmental factors including soil and vegetation in order to understand the environmental and ecological characteristics of four different habitats of Abelia tyaihyoni. These habitats, according to investigations, are mostly located at elevations of 203 m to 297 m with angles of inclination ranging from 9 degrees to 17 degrees. The litter depth of habitats is 2 cm to 5 cm. A total of 113 vascular plant taxa are identified in seven quadrates of the four habitats. The life form of 113 species is H-$D_4$-$R_5$-e type. The importance value of Abelia tyaihyoni is 39.61%, and 4 highly ranked species such as Quercus dentata (6.27%), Spiraea blumei, Spiraea prunifolia for. simpliciflora (4.04%) and Ulmus davidiana var. japonica (3.84%) are considered to be an affinity with Abelia tyaihyoni in their habitats. The dominant species of woody plants in the four habitats are represented as Pinus densiflora (21.22%) and Quercus dentata (16.82%) in the subtree layer (T2), and Carex humilis var. nana (18.95%) and Carex lanceolata (17.63%) in the herbaceous layer (H). The degree of their average species diversity is 1.42, and that of dominance and evenness are 0.07 and 0.86, respectively. The type of soil is sandy loam, clay loam and loam, and the average field capacity of soil is 22.49%. Their average organic matter is 9.39%, soil pH 6.75, and available phosphorus is $1.23 {\mu}g/g$.

• The Korean Journal of Mycology
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• v.48 no.2
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• pp.125-133
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• 2020

A new oak mushroom cultivar 'Hwadam' was bred from monokaryotic strains of 'GMLE36062' and 'LE15401'. The optimum temperature for mycelial growth of 'Hwadam' on potato dextrose agar was 25℃. The cultivation period of 'Hwadam' lasted for 129 days until the first harvest of the fruiting bodies, including 35 days for spawn run, 84 days for browning, and 10 days for development of fruiting bodies. The fruiting bodies of 'Hwadam' had a hemispherical, brighter pileus and thicker stipe than the control cultivar (Sanjo 701ho). The three-cycle yield of 'Hwadam' was 554 g, which was higher than that of control cultivar (405 g). In addition, 'Hwadam' contained 79.4 mg/g of beta-glucan and 0.93 mg GAEs/g of phenolic compounds, which was similar to that of the control cultivar but higher than that of 'L808' and 'Chujae 2ho'.

• Journal of the Korean Magnetics Society
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• v.9 no.2
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• pp.111-120
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• 1999

The effects of annealing in rotating magnetic field after deposition on electromagnetic properties of $Co_{82}Zr_6Mo_{12}$ thin (200~1200 $\AA$) films prepared by RF-magnetron sputtering were investigated in terms of microstructure and surface morphology. The coercivity decreases, but $4{\pi}M_5$ does not change with increasing the film thickness. The coercivity of the films was decreased below 300 $^{\circ}C$ due to stress relief and decreasing the surface roughness, while increased at 400 $^{\circ}C$ due to partial grain growth. And then, $4{\rho}M_5$ was almost independent of annealing temperatures below 200 $^{\circ}C$, but increased from 7.4 kG to 8.0 kG at 300 $^{\circ}C$ and at 400 $^{\circ}C$, which was caused by precipitation and growth of fine Co particles in the films. The electrical resistivity of films was decreased with increasing annealing temperatures and the magnetoresistance was a negative value of nearly 0 $\mu$$\Omega$cm. After annealing at 300 $^{\circ}C$, maximum effective permeability was 1200 to the hard axis of the thin films according to high frequency change. Considering the practical application of biasing layers of the films for magnetoresistive heads, optimal annealing conditions was obtained after one hour annealing at 300 $^{\circ}C$ in 400 Oe rotating magnetic field.

• Korean Journal of Plant Resources
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• v.25 no.5
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• pp.517-522
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• 2012

This study was conducted to investigate the morphological and anatomical characteristics of needle and the genetic diversity of Pinus pumila Regel which is a unique and the southern peripheral population in South Korea. ANOVA test showed that there were significant differences among individuals within population in all 8 needle characteristics. Average characteristics of 66 individuals were 53.59 mm in needle length, 0.78 mm in needle width, 68.98 in needle index, 0.65 mm in needle thickness, 4.56 ea. in maximum stomata row, 3.80 ea. in minimum stomata row, 8.36 ea. in total stomata row and 1.71 ea. in resin canals, respectively. Resin canal per needle of this species ranged from one to three, depending on external type. Especially, arrangement types were 69.47% in two resin canals and 30.45% in a single resin canal. A total of 78 bands was generated from 9 selected I-SSR primers. The estimates of genetic variation were 61.5% in proportion of polymorphic bands (P), 1.698 in effective number of alleles ($A_e$), 0.388 in expected heterozygosity ($H_e$) and 0.567 in Shannon's information index (S.I.), respectively.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 1998.11a
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• pp.19-20
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• 1998

오버레이용접에 의한 표면개질기술(Weld Surfacing or Hardfacing Technology)은 내식성, 내 마모성, 또는 내열성을 갖는 합금의 용접재료를 모재 표면에 균일하게 용착(오버레이:Ovedayer)시킴으로써 목적하는 재료의 표면성질을 향상시키는 표면처리의 한 방법이으로써 1922년 Stoody가 Steel Tube에 Cr합금 분말을 충진한 용접봉을 제조하여 석유시추용 회전드릴의 선단 표면을 오버 레이 용접시켜 내마모성을 획기적으로 개선시킴으로써 이루어 졌다. 초기 오버레이 용접기술은 발전설비I 제철설비I 시벤트설비, 그리고 제지설비 등 주로 설비 부품들의 표면부 내마모성을 개선시키는 방향으로 주로 연구 개발이 이루어졌으나, 기술개발의 진전으로 탈황설비 둥의 표면부 내식성 향상, 연속주조롤 표면부의 내산화성, 내열피로성, 내마모 성 향상 둥을 위해 점차 산업전반에 널리 이용되고 있으며, 설비의 고도화 및 장수명화가 요구되 면서 본 기술의 중요성 또한 점차 부각되고 있다. 그림 1은 연강의 모재 위에 셀프쉴드플럭스코어드와이어(Self-Shield Flux Cored Wire:SS-FCW, 이하 55-FCW라 기술함)를 사용하여 오버레이 용접올 하는 장면을 도식적으로 나 타낸 것이다. 모재와 전극재인 용접봉(S5-FCW) 사이에서 아크가 발생되고, 아크열에 의해서 용접 봉 및 모재 일부가 용융되면서 모재 표면에 새로운 오버레이 표면층이 형성된다. 통상 오버레이 층의 1층 두께는 2-6mm 내외이며, 단층 혹은 다충 오버레이를 자유롭게 실시한다. 오버레이층의 물성은 아크열에 의한 모재로의 용입정도에 따라 1층부에서는 모재의 영향을 크게 받지만 오버레 이충 수가 증가된 3층부에서 부터는 전적으로 용접봉의 성분에 좌우된다. 사진 1은 연강(55-41)의 모재위에 크롬탄화물이 다량 함유된 고크롬 탄화물형 내마모재가 오버 레이된 내마모 복합강판 (wear plate)의 단면 미세조직 사진으로써 모재부와 오버레이충을 함께 보여주고 있다. 모재와 오버레이 충간의 경계면은 모재 일부가 용융된 후 웅고하면서 형성됨으로 인해서 도금이나 용사층과는 달리 매우 견고하게 결합되어 있다. 따라서 계면부의 탈락이라는 문 제점은 거의 없어 심한 응력을 받는 기계구조물 및 부품에도 본 기술은 널리 적용되고 있다. 그리고 사진 1에서 알 수 있는 바와 같이 모재와는 전혀 상이한 재료를 자유로이 선택하여 표면 유효층 일부만 오버레이시키며I 주조 및 단조가 불가능한 재료까지도 표면부에 오버레이 시킴으로 서 부품 및 설비의 제조에 있어 재료비의 절감과 제품의 수명이 획기적으로 개선될 수 있다. 그리고 최근에는 도금 빛 용사 둥과 같은 표면처리를 할 경우임의 소재 표면에 도금 및 용 사에 용이한 재료를 오버레이용접시킨 후 표면처리를 함으로써 보다 고품질의 표면층을 얻기위한 시도가 이루어지고 있다. 따라서 국내, 외의 오버레이 용접기술의 적용현황 및 대표적인 적용사례, 오버레이 용접기술 및 용접재료의 개발현황 둥을 중심으로 살펴봄으로서 아직 국내에서는 널리 알려지지 않은 본 기 술의 활용을 넓이고자 한다.