• Journal of the Korean Magnetics Society
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• v.5 no.4
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• pp.287-293
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• 1995

자성물질의 자구를 관측하고, 표면의 자기전하를 측정하는 간단하면서도 정량적인 방법을 제시하였다. 관측방법은 자기 garnet film을 사용하며, 이 방법을 이용하여 {100} 철단결정 표면의 자구를 관측할 수 있었다. garnet film의 자구는 garnet 면과 수직한 자기장에 의해서만 변하고 임계 자기장에서는 사라진다. 그러나, 철단결정의 자구는 단결정 표면에 평행하게 걸어준 자기장에 대하여서는 영향을 받지만 수직하게 가한 자 기장에는 아무런 영향을 받지 않는다. 위와 같이 성질을 이용하여 철단결정과 평행한 자기장을 가할 때 철단결정의 자구에 유도된 전하에 인하여 garnet film의 자구가 변화하며, 이 garnet film의 자구는 편광된 빛을 이용하여 직접 관측할 수 있다. 이 방법으로 철단결정의 표면에 유도 되는 자기전하 분포를 측정할 수 있었고, 또한 단결정에 걸어준 전류가 변할때 단결정 자구의 움직임을 관측할 수 있었다. 이 관측한 결과 를 이용하여 철단결정에 전류를 가할 때의 비대칭적으로 유도되는 교류 자기감수율 실험의 결과를 설명할 수 있었다.

• Journal of Practical Agriculture & Fisheries Research
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• v.19 no.1
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• pp.75-82
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• 2017

This experiment was carried out to establish growth characterestics and number of bulblet, bulb weight, and diameter of bulblet on scale tissue culture in Lilium brownii. Flowering date of Lilium brownii was 25th, May with 50cm hight in field condition. Vimyl house condition was flowered 28th May with 54cm hight. Number of bulblet, bulb weight, diameter of bublet was good position of outer>Middle>inner scale in Lilium brownii. Number of bulblet formation was the best with 3.5 in large scale. Concentration of BA was the best at 1.5mg/L with 3.8 bulblet with bulb weight, weight and diameter of bulblet.

• Korean Journal of Plant Tissue Culture
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• v.26 no.2
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• pp.103-107
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• 1999

The effects of MS salt strength, sucrose, and cultural conditions on bulblet formation and growth were investigated to optimize the conditions for micropropagating bulblets from in vitro bulb scales of Lilium Oriental Hybrid 'Casa Blanca'. There was no difference on bulblet formation in the range of 1/2~2 $\times$ strength of MS salt, but it was inhibited remarkably in 3 $\times$ strength of MS salt. The growth of regenerated bulblets was most stimulated on MS basal medium. Favorable bulblet formation and its growth from bulb scales were achieved when grown on the media with 1 : 2 or 1 : 3 in the ratio of NH$_4$^+ : NO$_3$^- , as well as on MS basal medium (NH$_4$^+ : NO$_3$^- = about l : 2). Therefore, MS basal medium was very suitable for bulblet formation and growth from bulb scales. Bulblet formation was inhibited but its growth was stimulated with increase sucrose concentration in the medium. The growth of regenerated bulblets was very effective on the media with 9~12% sucrose. Addition of activated charcoal (AC) to the medium inhibited bulblet formation from bulb scales, but enhanced the growth of regenerated bulblets. Especially, the medium containing 1 g/L AC was most effective on the growth of bulblets. No difference was found on bulblet formation and growth from bulb scales under light and dark conditions. In vitro micropropagation of L. Oriental Hybrid 'Casa Blanca' was supposed very reasonable to enhance the growth of the bulblets after forming of bulblets from in vitro bulb scales, and then, subculture the bulb scales from the grown bulblets on MS medium with 9% sucrose and 1 g/L AC.

• Journal of Life Science
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• v.12 no.6
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• pp.740-744
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• 2002

This experiment was conducted to clarify the effects of physiological properties in culture media on the proliferation and the acclimation of bulblets of several kinds of lilies cultured in vitro. Proliferation rate of bulblets from bulblet of Oriental hybrid ‘Marco Polo’, ‘Casa Blanca’ and Asiatic hybrid ‘Jolanda’ was higher in solid MS media compared with bulblets from scale Acclimation rate of regenerated bulblets was high in solid media which was pre-cultured in vitro, compared with liquid media. Sprouting rate of bulblets from bulblet was higher than bulblets from scale.

• Korean Journal of Plant Tissue Culture
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• v.28 no.3
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• pp.135-140
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• 2001

A series of studies were carried out to establish micropropagation system, using airlift bioreactors (ebb $\varepsilon$ flood type, 5 L), of Lilium oriental hybrid 'Casa Blanca'. The bulblets with swollen basal plate were formed from bulb scales, then proliferated to bulblet clusters with swollen basal plate. Finally normal bulblets were formed from the sections. Bulblet formation and proliferation with swollen basal plate were not accomplished entirely in liquid culture of 5 L airlift bioreactors, but leafy bulb scales grew vigorously. Bulblet clusters with swollen basal plate were proliferated by periodic immersion culture. Bulblet proliferation was not affected by light, but scale leaves grew under light. MS medium containing 2.0 mg/L benzyl adenine (BA) and 0.3 mg/L indole acetic acid (IAA) was favorable to the bulblet proliferation with swollen basal plate. In liquid culture of 5 L bioreactors, bulblets from bulblet sections with swollen basal plate grew vigorously on MS medium with 70 g/L sucrose. It was effective for bulblet growth to replace the new medium after 8 weeks in culture during 16 weeks of cultural period. 15 g injection of bulblet sections as a cultural material was suitable for bulblet growth in 5 L bioreactors.

• Korean Journal of Plant Tissue Culture
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• v.22 no.2
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• pp.89-93
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• 1995

Regeneration and growth of bulblets from bulblet-derived bulb-scale segment of Lilium longiflorum (cv Georgia) were investigated. Bulblets were initiated on bulb scales taken from bulblets on MS medium containing 0.05 mg/L 2,4D with 3% sucrose or 0.02 mg/L 2,4D with 9% sucrose. Benzyladenine promoted the differentiation of bulblets but inhibited the growth of differentiating bulblets. The growth of bulblet was promoted by supplying 1/2 strength 1/2 NH$_4$NO$_3$ concentration in MS medium containing 12% sucrose.

• Electrical & Electronic Materials
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• v.1 no.4
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• pp.319-332
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• 1988

높은 포화자속밀도와 낮은 철손을 갖는 Fe/aub 80/B$_{12}$Si$_{8}$ 비정질합금을 일반열처리, 자장열처리시켜 그의 자기적특성과 자구구조와의 관계를 조사하였다. 이를 위하여 Fe$_{80}$B$_{12}$Si$_{8}$ 비정질리본을 단롤법으로 제작하여 결정화온도를 측정하였으며 측정된 결정화온도 이하의 여러 온도에서 30분간 Ar-gas 분위기하에서 일반열처리, 자장열처리를 행하였다. 이와같이 하여 준비된 시료의 자기적특성을 조사하기 위하여 D.C., A.C. Recorking Fluxmeter를 이용하였으며 자구구조는 Bitter method로 관찰하였다. as-cast 상태의 시료를 일반열처리함에 따라 내부응력이 완화되면서 maze자구가 점차 사라지고 wave형태의 180.deg.자구가 관찰되었다. 동시에 자화과정에 있어서 자기이력곡선은 Barkhausen jump가 없어 smooth하였다. 그리고 자장열처리시에는 as-cast 상태나 일반열처리에 비해 자기적특성이 현저하게 향상되었으며 이는 열처리를 행함에 따라 내부응력이 완화되면서 maze 자구가 없어지고 일축자기 이방성으로 리본길이방향에 평행하게 형성된 180.deg.자구에 기인하는 것이라 사료된다. 그리고 자장열처리의 경우, 폭방향으로 열처리한 리본의 자구폭은 길이방향으로 열처리한 리본의 폭보다 미세하였으며 전자의 이력손실이 후자의 것보다 더 컸다.다.

• Journal of the Korean Magnetics Society
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• v.25 no.6
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• pp.180-184
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• 2015

We have investigated the magnetization reversal behavior in ferromagnetic $Co_{0.5}Fe_{0.5}$ alloy films using the magneto-optical Kerr microscope capable of the direct observation of time-resolved domain patterns. Interestingly enough, as the sample thickness increases the magnetization reversal behavior becomes changed from a single domain wall motion to the random nucleations of domains. Also, from the stochastic analysis of the domain jump sizes during the domain wall motion, it was found that the magnetization reversal behavior in the samples shows the critical scaling behavior with the critical exponent of ${\tau}{\sim}1.33$.

• Journal of the Korean Magnetics Society
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• v.27 no.1
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• pp.35-40
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• 2017

Kerr microscopy was assembled to observe magnetic domain image of ultra thin 3 %Si-Fe by using parts of an optical microscope. Digital images were obtained from CCD camera attached to the microscopy. A method was suggested to decide a boundary between magnetic domain regions in this study. The method was using some operations such as subtraction, integration and least mean square approximation for pixel values in the digital image. The method has a strong point that high priced image processor is not needed in the Kerr microscopy system. From the results that three different domain walls were observed and magnetic flux density of 0.085 [T], this method could be applied in the magnetic domain regions having a straight $180^{\circ}$ domain wall.

• Korean Journal of Medicinal Crop Science
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• v.2 no.2
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• pp.154-161
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• 1994

This experiment was carried out to establish micropropagation system in Fritillaria thunbergii Miq. Through the culture of bulblet scales, stems, node-buds and shoot tips with special reference to the effect of physiological age of explant and plant growth regulators on bulblet formation. Number of formed bulblets was significantly increased in node-bud or stem tissue compared to scals segments and on the medium supplemented with kinetin than BA containing medium. Optimum levels of kinetin for bulblet formation from node-bud taken from above 3 cm shoot length and stem segments excised from below 3 cm shoot length were 5.0 mg /L and $1.0{\sim}3.0\;mg$ /L kinetin, respectively. Interesting phenomenon was observed, the direct formation of bulblets from the axilliary bud of cultured explants. Bulblet forming capacity in stem tissue was depended on stem age, young stem had high regeneration ability compared to old stem taken from above 10 cm shoot length. 1.0 mg /L kinetin was optimum concentration for the formation of bulblets from old stem segments. Stem tissue taken from underground growing plant was promoted coampare to shoot tips or bulb scale segments. Optimum concentration of sucrose was $5{\sim}7%$. Summariged above results revealed that effective explant for micropropagation was stem and /or node-bud tissue excised from less than 3 cm plant height compared to those of bulb scale segments which showed high contamination after culture. Maximum multiplication rate of young stem and /or node-bud segment was about 20 times. Kinetin requirement for stimulation of bulblet formation from cultured explant depended on source of explants but favorable levels of kinetin for organogenesis ranged from 1.0 mg /L to 5.0 mg /L.