• 한국결정성장학회지
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• 제22권6호
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• pp.265-268
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• 2012

대형의 고품질 AlN 단결정은 자외선 LED 및 전력 반도체 소자용으로 중요성이 크다. 그러나, 아직 1인치급의 고품질 단결정에 대해서는 보고된 바가 없다. AlN 성장을 위한 PVT 공정에서는 성장 속도 증가를 위하여 성장 결정의 형상을 고찰하는 것이 매우 중요하다. 본 연구에서는 PVT 공정으로 성장된 AlN 결정의 성장 형태에 대하여 고찰하였다. 광학현미경을 이용하여 결정의 형태와 성장 facet에 대하여 관찰하고, 결정의 성장 습성과 관련하여 고찰하였다.

• Membrane and Water Treatment
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• 제15권1호
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• pp.11-19
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• 2024

This study presents the characteristics of growth and morphology of Anabaena sp., a representative filamentous cyanobacterium, depending on temperature variation from 10 to 30 ℃. Both the filament density (or number) and its length of Anabaena were highly affected by temperature, as well as growth stage. Rapid growth at a higher temperature led to an increase in Anabaena filament density, as well as optical density at 680 nm (OD₆₈₀). However, the number of vegetative cells within a single filament of Anabaena grown at 30 ℃ was smaller than those grown at lower temperatures, due to the intercalary division of the filament. Of the three different cells comprising a single Anabaena filament, the vegetative cell marginally affects the growth of Anabaena. The main dimensions of the vegetative cell, i.e., length and width, depend on the temperature and growth stage. The length-to-width (L/W) ratios of vegetative cells and akinetes were relatively consistent regardless of the temperature. However, in vegetative cells with dichotomous growth, the L/W ratio shows clear differences depending on their growth stage. It has been demonstrated that the L/W ratio could be used as an indicator to indirectly predict the growth stage of on-sit Anabaena samples.

• Journal of Electrochemical Science and Technology
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• 제14권2호
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• pp.194-204
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• 2023

Models based on diffusion-limited aggregation (DLA) have been extensively used to explore the mechanisms of dendritic particle aggregation phenomena. The physical and chemical properties of systems in which DLA aggregates emerge are given in their fractal. In this paper, we present a comprehensive study of the growth of electrodeposited copper dendrites in flat plate electrochemical cells from a fractal perspective. The effects of growth time, applied voltage, copper ion concentration, and electrolyte acidity on the morphology and fractal dimension of deposited copper were examined. 'Phase diagram' set out the variety of electrodeposited copper fractal morphology analysed by metallographic microscopy. The box counting method confirms that the electrodeposited dendritic structures manifestly exhibit fractal character. It was found that with the increase of the voltage and copper ion concentration. The fractal copper size becomes larger and its morphology shifts towards a dendritic structure, with the fractal dimension fluctuating around 1.60-1.70. In addition, the morphology of the deposited copper is significantly affected by the acidity of the electrolyte. The increase in acidity from 0.01 to 1.00 mol/L intensifies the hydrogen precipitation side reactions and the overflow path of hydrogen bubbles affects the fractal growth of copper dendrites.

• 한국결정성장학회지
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• 제18권5호
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• pp.184-190
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• 2008

단순 침전법으로 타원, 땅콩, 아령, 바디가 있는 구형 모양의 $CaMoO_4$ 결정을 합성하였다. $Ca^{2+}$ 이온과 $MoO_4^{2-}$ 이온 농도가 증가함에 따라서 $CaMoO_4$의 형태는 차원형에서 땅콩 모양과 아령 모양을 거쳐서 마디가 있는 구형 모양으로 전개됨을 확인하였다. 이러한 $CaMoO_4$ 결정의 형태의 전개는 프랙탈 메커니즘에 기인한다. 타원형의 양 끝 부분에서부터 가지를 치면서 결정 성장이 시작된다. 1차와 2차 프랙탈 성장에 의해서 땅콩 모양과 아령 모양이 각각 형성되었다. 아령 모양에서 더 프랙탈 성장을 하여 최종적으로 마디가 있는 구형이 형성되었다.

• 한국결정성장학회지
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• 제11권1호
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• pp.1-5
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• 2001

승화법에 의하여, 여러 조건의 성장압력과 성장온도에서 SiC 단결정을 성장시켰다. 성장된 단결정을 광학현미경으로 관찰하여 성장 step의 형태와 양상을 관찰하였으며, 성장 step의 morphology와 결정 성장 인자와의 상호 연관성에 대하여, 핵생성과 결정성장에 관한 BCF 이론을 적용시켜 고찰하였다.

• 한국물환경학회지
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• 제36권6호
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• pp.559-567
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• 2020

The abnomal responseses on growth and morphology of attached diatoms by various heavy metals were studied. Ulnaria ulna (Nitzsch) Compère was employed as experimental species and exposed to the five heavy metals such as Cu, Zn, Pb, Cd, and As with four concentrations (0, 0.01, 0.1, and 2 mg L-1), respectively. The samples of Ulnaria ulna were examined on the changes of cell growth and teratological forms on the 7th, 14th, 21th, and 28th day, respectively, after exposure to the heavy metals. The samples exposed to the highest concentration, 2.0 mg L-1, of all the heavy metals showed the most obvious decreases of growth. The samples exposed to Cd (μ=0.049day-1) and As (μ=0.048day-1) showed the highest decreasing rate of growth (p=0.021(Cd), p=0.002(As)) and the highest morphological changes of diatom valves were also samples exposed to Cd (10.41%) and As (10.13%) (p=0.009 (Cd), p=0.005(As)). In contrast, Pb induced the lowest decreasing rate (μ=0.090 day-1) and the least change in valve morphology (3.31%). The Cd and As showed relatively stronger effects on growth rates compared to Cu, Zn, and Pb. For the percentage of emergence of morphological species by the type, the highest percentage were observed in sampled exposed to type 1 (43.4%) and followed by type 2 (29.1%). The type 2 and 4 were most abundant in samples exposed to Zn and Pb while the type 3 was most abundant in Cd and As. The Cu induced only type 1, suggesting that the frequency of emergence of each type varied among hevay metals. This research suggests that the degrees of abnomal changes on growth rate and valve morphology of Ulnaria ulna can be used as a bioindicater species for heavy metal contamination in freshwater.

• 한국결정학회지
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• 제11권4호
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• pp.207-211
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• 2000

In a Czochralski silicon single crystal, the relation between the growth twin and the crystal morphology was investigated. The growth twin is nucleated on the {111} facet planes near the growth ridges. When a {111} growth twin is formed in the <100> silicon crystal, the growth ridge where twin is nucleated will continuous through the twin plane. Other two ridges at the 90。 apart will be displaced about 33° and be deformed to facets. The ridge on the opposite side of twin nucleation will disappear by forming a slight hill. Because the growth ridges of silicon is due to the {111} planes, the variation in the growth ridge formation can be predicted clearly by considering the change of the {111} plane traces in the stereographic projection after twining.

• Journal of Ginseng Research
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• 제27권4호
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• pp.178-182
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• 2003

Vesicular-arbuscular mycorrhizae (VAM) fungi naturally colonise American ginseng roots and this relationship is highly beneficial to enhance plant productivity. Our goal was to determine the effect of adding two Glomus species (Glomus etuticatum, G. intraradices) on survival, photosynthetic capacity, growth, morphology and root ginsenoside content of one-year-old American ginseng plants grown in a broadleaf forest. While our study revealed that VAM inoculations significantly affected root morphology and Re ginsenoside content, the survival, photosynthetic capacity and root growth of American ginseng plants were not significantly influenced by VAM inoculations. Surface area and volume of rootlets were 16-25% higher for ginseng grown in VAM-inoculated soil compared to those grown in the control plots. Also, Re ginsenoside content was 18 ％ higher in YAM-inoculated roots compared to controls.

• 한국결정성장학회지
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• 제5권3호
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• pp.197-208
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• 1995

과냉각도가 0.35 K보다 작은 영역에서 ice dendrite의 결정 성장 특성 및 morphology는 과냉각도 뿐만 아니라 자연대류의 함수임을 관찰하였다. 즉, 결정 성장에 대한 자연대류의 영향은 결정 성장 자체에 의한 moving boundary 효과보다 우세함을 알 수 있었다. 본 실험 범위에서 ice dendrite의 성장 속도 및 tip size(edge 및 basal plane)를 과냉각도의 함수로 정량화하였다.

• 산업기술연구
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• 제21권A호
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• pp.337-341
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• 2001

This study was carried out to screen the effective polymeric additives preventing wall growth during mycelial submerged cultivation of Ganoderma. lucidum. Effects of additives on mycelial growth and exo-polysaccharide (EPS) production in flask culture and jar fermenter system under 3 different pH processes were investigated, and changes of mycelial morphology were also examined. From flask culture of G. lucidum with additives of different concentrations, 0.1%(w/v) polyacrylic acid was effective for EPS production. As the polyacrylic acid of 0.1%(w/v) was added in medium, wall growth of G. lucidum mycelium grown in jar fermenter system could be protected. The addition of 0.1%(w/v) polyacrylic acid to medium was also improved the mycelial growth and EPS production in the later of submerged culture G. lucidum and no changes of mycelial morphology were observed.