• Journal of the Korean Wood Science and Technology
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• v.37 no.6
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• pp.531-536
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• 2009

Radial variations of ray spacing and frequency of biseriate ray were examined in the woods of most commercially important Korean softwood species of Pinus koraiensis and Larix kaempferi. Ray spacing, or ray number per mm in cross section, averaged 4.6 and 9.0 in Pinus koraiensis and Larix kaempferi, respectively. Thus, rays of Larix kaempferi appeared to be more closely arranged than those of Pinus koraiensis. Ray spacing was the densest around pith, and then slowly decreased toward bark. In tangential section, biseriate ray frequency of Larix kaempferi was higher than that of Pinus koraiensis. Biseriate ray was designated, based on the number of cells of biseriate portion in vertical extent, as the type of B+1 (one cell high), B+2 (two cells high), and so on. The dominated type was B+1 in Pinus koraiensis but B+2 in Larix kaempferi. The biseriate ray types of B+3, B+4, and B+5 were occasionally found in earlywood. Interestingly, even B+6 and B+7 types were observed in Larix kaempferi. In conclusion, it was considered that ray spacing could be used for separating juvenile wood from adult wood. Also, characteristics of ray spacing and biseriate ray might be used for identifying these two species.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.13 no.3
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• pp.280-285
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• 2008

Manganese nodule abundance estimated based on operation of a Free Fall Grab(FFG) needs to be corrected to make up for its incomplete recovery of nodule, because FFGs can not recover all the nodules distributed on seabed. The correction factor for nodule abundance was proposed as 1.29 and 1.13 in 1994 and 2002, respectively, mainly based on the analyses of seabed images. In this study we collected manganese nodules using both FFG and Box Corer(BC) at same stations to examine the accuracy of the previous correction factors. It was found that the nodule recovery of the BC was 1.4 times greater than that of the FFG at the same sampling station, suggesting the necessity of re-evaluation of the previously proposed correction factor for FFG. More extensive sampling and improvement of image analysis method are required to improve the precision of nodule abundance correction factor for FFG.

• Applied Microscopy
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• v.12 no.1
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• pp.49-56
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• 1982

A case of systemic cryptococcosis developed in 4 year old boy was described and illustrated by light and electron microscope. Light microscopically, the upper dermis of the skin showed chronic nonspecific inflammation with numerous spherical spores surrounded by a clear halo created by the wide gelatinous capsule. Ultrastructurally, the C. neoformans showed the wide capsule containing microfibrils that appeared to radiate from the cell wall and to coil and interwine in various directions. The cell was uninucleate with a single nucleolus. Along the inner nuclear envelope, numerous small vesicles were present. In addition, C. neoformans presented membranous organelles derived from the plasma membrane and comparable to bacterial mesosomes.

• Journal of Korean Society of Transportation
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• v.25 no.3
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• pp.19-28
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• 2007

Korea's national highways, which emphasize a high level of mobility, serve primarily intercity travel and are used as a detour for freeways. However. at the present. the highways do not have consistent geometric features or other characteristics: for example. some highways have full access control and others have uncontrolled access. Generally, geometric and traffic conditions affect Pronouncedly travel speeds in the highway sections. This study focused on the effect of signalized intersection relative factors on the speeds: signalized intersection densities, signal phases, and volume levels. The study shows that signalized intersection density was the strongest variable affecting the travel speeds: the speeds held fairly constant over intersection densities below 0.3 intersections/km, decreased sharply through intersection density of 0.7 intersections/km. and appeared constant at the lowest level over intersection densities above 0.7 intersections/km. The results also indicate that the effect of signal and traffic volume levels on the speeds was similar to that of the signalized intersection density.

• Journal of the Korean Magnetics Society
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• v.25 no.4
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• pp.106-110
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• 2015

We have studied electronic and magnetic structure of 2 kinds of diiron molecules using OpenMX method based on density functional method. The calculated density of states of diiron-2 is similar with that of diiron-4 because of equal number of 6 ligand atoms. The calculated total energy with antiferromagnetic spin configuration is lower than those of ferromagnetic configurations for both of them. The exchange interaction J of diiiron-4 between $Fe^{+3}$ atoms is one order larger than that of diiron-2, and the calculated J matches well with the experimental one. That comes from the short distance of Fe-O and the high O 2p energy levels. It derives a strong super exchange interaction. The angle of diiron-4 between Fe atoms is bigger than that of diiron-2. It also derives a strong super exchange interaction because of the ${\sigma}$-bond between Fe and O atoms.

• Journal of Adhesion and Interface
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• v.16 no.2
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• pp.76-82
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• 2015

W/O emulsions were prepared from the aqueous solution containing NIPAAm, MBA, and APS in the continuous phase of toluene and mineral oil mixture with HMP and Span80 by using SPG membrane emulsification, and followed by the formation of PNIPAAm hydrogel microspheres through UV photopolymerization. As the ratio of mineral oil to toluene increased in the continuous phase, both particle size of the hydrogel increased and density of PNIPAAm polymer in the hydrogel particle increased, and which significantly affected swelling/deswelling ratio ($V/V_o$) with temperature change around VPTT. When the polymerization temperature was below LCST ($20^{\circ}C$), PNIPAAm hydrogel showed filled particle morphology; however, it was turned out to hollow particle morphology with thick shell layer with $40^{\circ}C$. Both density of PNIPAAm and gel content of the hydrogel increased with the increase in MBA concentration.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.13-13
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• 2020

'20년 3월 현재 전국 3,502개 읍면동 중 73개 읍면동이 지하수를 상수원으로 급수 중이며, 48개 산업단지에서 지하수를 주 수원으로 사용 중이다. 또한 급수 소외지역의 물 공급을 위해 주로 사용되는 소규모수도시설 14,811개 중 12,073개(81.5%)는 지하수를 이용하고 있으며, 그 위치는 전국에 산재해 있다. 이처럼 지하수는 댐, 저수지 및 하천과 더불어 생·공용수의 중요한 수원이라 할 수 있다. 본 연구에서는 급수 소외지역의 주요 수원인 지하수위 현황을 이용한 가뭄 모니터링 및 전망 기법을 개발하고자 하였다. 국가 지하수관측망 중 10년 이상 장기 관측 자료를 보유한 253개 관측소의 일단위 관측자료를 기반으로, 과거 관측수위 분포를 핵밀도함수로 추정하고 Quantile Function을 이용해 현재 수위의 높고 낮은 정도를 Percentile 값으로 산정하였다. 관측소별 지하수위 Percentile은 티센망을 이용해 167개 시군별로 공간평균하고 Percentile의 범위에 따른 가뭄등급을 설정하여 지하수 가뭄 정도를 모니터링 할 수 있는 기법을 제시하였다. 또한 지하수 가뭄을 전망하기 위해 강수와 지하수위의 거시적인 응답특성을 이용하였다. 관측소별로 추정된 핵밀도함수의 누적확률을 표준정규분포의 Quantile로 변환하여 표준지하수지수I(Standardized Groundwater level Index, SGI)를 산정하고, 시군별로 공간을 일치시킨 1~12개월 지속기간별 표준강수지수(Standardized Precipitation Index, SPI)와의 상관관계를 이용해 NARX(nonlinear autoregressive exogenous) 인공신경망 예측모형을 구축하였다. 이를 통해 기상청 정량전망 강수량을 이용해 전국의 1~3개월 후 지하수 가뭄을 빠르게 전망할 수 있는 체계를 구축하고, 생·공용수 분야 국가 가뭄 예·경보의 미급수지역 가뭄현황 및 전망에 활용중이다.

• Journal of the Korean Regional Science Association
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• v.40 no.3
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• pp.43-61
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• 2024

The purpose of this study is to identify the difference of regional characteristics affecting 'marriage stage' and 'childbirth stage' and to compare how these factors differ between metropolitan and non-metropolitan areas using a heckman two-stage selection model. The main findings are as follows. First, regional characteristics affecting marriage stage and childbirth stage are different. Second, in the metropolitan area, regional characteristics such as population density, the proportion of female employee, and housing prices have a relatively greater impact on 'marriage', and in the non-metropolitan area, regional characteristics such as population density and unemployment rate have more impact on 'childbirth'. The empirical analysis suggests that marriage and childbirth stage need to be distinguished when establishing low fertility policies, and these approaches should be differentiated at regional level.

• Journal of The Korean Society of Grassland and Forage Science
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• v.24 no.3
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• pp.225-230
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• 2004

Jeju native sorghums were grown with six different planting densities ($5{\times}5cm,\;10{\times}10cm,\;15{\times}15cm,\;20{\times}20cm,\;25{\times}25cm\;and\;30{\times}30cm$) from April 3 to September 6 in 2000 in Jeju island to determine the influence to growth, yield and feed value by the planting densities. Days to heading were delayed from 66 days to 69 days as increasing of plant density. Plant height was 195.1cm at $30{\times}30cm$ plot, whereas that was 216.5cm at $10{\times}10cm$ plot, indicating that the plant was higher by the decrease of the planting density. As plant density increased, the number of leaves and steam diameter were decreased. Fresh forage yield increased from 25.4 to 61.3 MT/ha, dry matter (DM) yield from 5.8 to 16.5 MT/ha, crude protein (CP) yield from 0.4 to 1.5 MT/ha and total digestible nutrients (TDN) yield from 2.7 to 8.8 MT/ha as planting density from $30{\times}30cm\;to\;10{\times}10cm$ plot. Crude protein content increased from 7.0 to $9.0\%$, ether extract content from 1.7 to $4.4\%$, nitrogen free extract content from 36.9 to $38.4\%$ and TDN content from 46.1 to $55.5\%$ as planting density was decreased. whereas crude fiber content decreased from 43.9 to $37.1\%$ and crude ash content from 8.4 to $6.8\%$.

• Korean Journal of Materials Research
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• v.7 no.11
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• pp.986-990
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• 1997

LED와 LD의 수명과 효율은 결정에 존재하는 결함의 밀도에 반비례하며, 이러한 결함의 밀도는 적당한 기판을 사용하거나, 기판의 표면을 적절하게 제어함으로써 줄일 수 있다. GaN성장시 원자 단위의 매끄러운 표면은 완충충 성장이나 질화처리를 함으로써 얻어질 수 있다. 이렇게 얻어진 원자 단위의 매끄러운 표면에 의해 기판과 박막상이의 계면 자유에너지가 감소하기 때문에 2D성장이 촉진된다. 사파이어(AI$_{2}$O$_{3}$(0001))기판을 사용한 GaN 왕충충성장과 진화처리에 대한 최적조건은 AFM(Atomic Force Microscope)측정 결과에 의해 결정되었다. AFM에 의해 얻어진 표면 평활도의 개념은 사파이어 기판을 사용한 GaN박막성장의 최적조건을 결정하는 데 있어서 높은 신뢰도를 가질 수 있다.