• 식물조직배양학회지
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• 제27권5호
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• pp.411-413
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• 2000

The ability of microspores or young pollen grains (male gametophytes) to undergo developmetal switch to embryogenic (sporophytic) pathway exemplifies the concept of totipotency as applied to haploid posmeiotic cells. As a first step pollen is devoid of positional information provided in situ by the intact anther - by isolation and cultivation in vitro in artificial media. This is inevitably accompanied by some degree of stress response in microspore/pollen. It has been shown in both monocots and dicots that intentional stress treatment (mostly starvation or heat shock) greatly stimulates embryo induction rate. Using transgenic sHSP antisense Nicotiana tabacum we show that expression of small heat shock proteins is an integral part of successful embryo and later haploid plant production from pollen grains. Our recently published data show that sHSP chaperone function is optimal in the absence of ATP.

• Transactions on Electrical and Electronic Materials
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• 제15권3호
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• pp.117-124
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• 2014

The calculation of short-circuit currents is important for power systems operation and restoration, and for determining the means to protect human lives and properties. In this paper, a part of a power system network, around the D$\breve{e}$tmarovice power station in Czech Republic, was simulated by the well known program EMTP-ATPDraw (Electromagnetic Transients Program-Alternative Transient Program), and short-circuit currents and voltages were calculated at different points in the electric network and presented as a time function by the PlotXY program. Calculations were done just for phase-to-ground, and for the three-phase short-circuit at the Kun$\check{c}$ice substation. The results were important for determining the characteristics of the equipment required to withstand or break the short-circuit current; for this reason, the calculations were repeated using earth-fault resistances only for the case of busbar KUN shown in Figs. 5 and 6.

• 한국수학교육학회지시리즈D:수학교육연구
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• 제2권2호
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• pp.57-69
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• 1998

In the article, an analysis of solutions to six problems of geometrical character at the begining of school attendance is shown. Problems were assigned to students individually and were evaluated from different points of view. The previous research was focused mainly on their arithmetical competence. But geometry also belongs in primary education. Therefore we prepared an analogous investigation which was focused on geometrical competence. The experiment confirms that our children have, at the beginning of school attendance, a good level of visual appreciation of their surrounding world. Our schools do not systematically develop further this skill.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.601-605
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• 2004

Railway wheel is the important element of rolling-stock in the viewpoint of running safety. Thus, the material properties of strength, fatigue crack, durability are needed, and the standards for test and criteria of whee] are established to guarantee quality of wheel. In the meantime, the suppliers for wheel in domestic are varied from domestic monopolization to diverse company of China, Russia, Czech Republic, etc. The uniform quality of wheel is important from a maintenance point of view. We collected wheel samples of diverse vendors to analyze the uniformity of wheel on the basis of korea national standard. We tested material properties and analyzed the test data statistically.

• 대한기계학회논문집B
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• 제23권7호
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• pp.856-863
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• 1999

The thermal performance degradation of heat pipes is caused by the non-condensable gas generation mainly due to the electrochemical corrosion which results from the reaction of working fluids with tube materials. In this study, a simplified method described below was proposed to estimate the life of heat pipes concerning the non-condensable gas generation. The temperature distributions at the outer surface of heat pipes was measured, and based on them the amount of non-condensable gas of hydrogen was estimated. Applying it to the Arrhenius model, the mass generation of hydrogen and the volume occupied by the gas In heat pipes could be estimated for an operating temperature and time. Moreover, this simplified method was applied to the accelerated life test of nine methanol-stainless steel heat pipe samples.

• 한국결정성장학회지
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• 제12권1호
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• pp.21-26
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• 2002

Luminescence and scintillation properties of $PbWO_{4},\;XAIO_{3}$ (X = Y, Lu, Y-Lu) and $LiBaF_{3}$ based scintillators are reported. The effect of present and often not understood defect states is demonstrated in different scintillator parameters and related measurements are discussed. Importance of understanding of defect states participating in the processes of energy transfer and storage in the scintillating materials is emphasised.

• 한국표면공학회지
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• 제36권1호
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• pp.22-26
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• 2003

This short communication reports on the experiment which demonstrates that superhard nanostructured films with hardness of about 40 GPa and greater can be composed not only of two or more nanocrystalline and/or amorphous phases of different materials, as it is in the case of nanocomposite coatings, but also that can be formed by a mixture of small (<10 nm) nanocrystalline grains of the same material with different crystallographic orientation and/or lattice structures. This finding opens new possibilities to develop advanced nanostructured materials with enhanced physical and functional properties.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.145-148
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• 2000

In contrast to the $\pi$ -conjugated polymers which typically absorb light only in the visible spectral region, the $\sigma$-conjugated polymers can be used as efficient material absorbing light in the UV region. In this work, the electronic and optical properties of I$_2$-doped $\sigma$ -conjugated poly (methyl-phenylsilylene) (PMPSi) polymer were investigated. DC conductivity up to 1.2$\times$10$^{-4}$ S/cm was obtained by I$_2$-doping. In UV/Vis absorbance spectrum, a new peak was observed near 370 nm, which was explained by polaron model. The photoluminescence (PL) intensity decreased with increasing degree of I$_2$-doping, and the Infrared (IR) spectrum analysis revealed that the dopants are not directly coupled to the polymer, but effect motions of the methyl and phenyl groups.

• 지적과 국토정보
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• 제50권1호
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• pp.143-162
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• 2020

본 연구의 목적은 우리나라에 소개된 프랑스·네덜란드·일본·대만을 제외하고 지적제도와 토지등기제도의 통합사례를 조사 분석하여 그 유형을 도출하는데 있다. 연구 결과 터키·인도네시아·헝가리·체코·리투아니아 등에서 지적제도와 등기제도가 통합되어 있는 사실을 확인하였으며, 통합 사례를 분석한 결과 다음과 같이 세 가지 유형이 도출되었다. 첫째, 프랑스 형으로, 지적제도와 등기제도의 창설 당시부터 통합되어 중앙정부와 주정부는 행정부의 1개부에서 관장하고 있으나, 기초자치단체는 이를 분리하여 2개의 기관에서 관장하는 프랑스·터키 등이 있으며, 둘째, 네덜란드 형으로, 지적제도와 등기제도의 창설 당시부터 통합되어 행정부의 1개부에서 관장하는 네덜란드·인도네시아·리투아니아 등이 있고, 셋째, 일본 형으로, 지적제도와 등기제도의 창설 당시부터 분리되어 지적제도는 행정부에서, 등기제도는 사법부에서 관장하였으나, 이를 통합하여 행정부의 1개부에서 관장하는 일본·대만·헝가리·체코 등의 국가가 있다. 그리고 지적제도는 모든 국가가 행정부에서 관장하고 있으며, 등기제도는 일부 국가가 사법부에서 관장하고 있었으나, 통합한 후에는 모두 행정부에서 관장하는 것으로 분석되었다. 앞으로 지적제도와 등기제도의 통합사례에 관한 적극적인 연구가 이루어지길 바라며, 본 연구 결과가 지적과 등기제도의 통합 방안에 관한 연구의 기초자료로 활용될 수 있기를 기대한다.

• Journal of Electrical Engineering and Technology
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• 제13권6호
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• pp.2425-2433
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• 2018

This study investigates a new organic based material and its dielectric and mechanical properties. It is a comprehensive nanocomposite comprising a combination of various types of nanofillers with hydrophobic silica nanoparticles (AEROSIL R 974) as a matrix modifier and a polyamide nano nonwoven textile, Ultramid-Polyamide 6, pulped in the electrostatic field as a dielectric barrier. The polymer matrix is an epoxy network based on diglycidyl ether of bisphenol A (DGEBA) and cycloaliphatic diamine (Laromine C260). The designed nanocomposite material is an alternative to the conventional three-component composites containing fiberglass and mica with properties that exceed current electroinsulating systems (volume resistivity on the order of $10^{16}{\Omega}{\cdot}m$, dissipation factor tan ${\delta}=4.7{\cdot}10^{-3}$, dielectric strength 39 kV/mm).