• 한국분말재료학회지
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• 제13권4호
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• pp.263-268
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• 2006

In this study, the colloidal stability and sedimentation behavior of crystalline $TiO_2$ particles (300nm) in various organic solvents have been investigated by means of a backscattered light flux profile (Turbiscan). The backscattered light flux profiles revealed that the $TiO_2$ nanoparticles were readily sedimented in water, methyl alcohol, and ethyl alcohol due to a flocculation-induced particle growth, while a particle coalescence and a sedimentation of the $TiO_2$ nanoparticles were hardly observed in isopropyl alcohol. The migration velocities of the $TiO_2$ particle were measured as around 6.15/min, 12.53 m/min, 6.51m/min, and 0.18m/min for water, methyl alcohol, ethyl alcohol, and isopropyl alcohol, respectively, showing a remarkably slow migration of the $TiO_2$ particles in isopropyl alcohol.

• ALGAE
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• 제21권4호
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• pp.407-416
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• 2006

Low molecular weight carbohydrates, phycobilin pigments and cell structure using light and transmission electron microscopy were used to describe a new genus of unicellular red algae, Erythrolobus coxiae (Porphyridiales, Porphyrideophyceae, Rhodophyta). The nucleus of Erythrolobus is located at the cell periphery and the pyrenoid, enclosed by a cytoplasmic starch sheath, is in the cell center. The pyrenoid matrix contains branched tubular thylakoids and four or more chloroplast lobes extend from the pyrenoid along the cell periphery. A peripheral encircling thylakoid is absent. The Golgi apparatus faces outward at the cell periphery and is always associated with a mitochondrion. Porphyridium and Flintiella, the other members of the Porphyrideophyceae, also lack a peripheral encircling thylakoid and have an ER-mitochondria-Golgi association. The low molecular weight carbohydrates digeneaside and floridoside are present, unlike both Porphyridium and Flintiella, which have only floridoside. The phycobilin pigments B-phycoerythrin, R-phycocyanin and allophycocyanin are present, similar to Porphyridium purpureum. The cells have a slow gliding motility without changing shape and do not require substrate contact. The ultrastructural features are unique to members of the Porphyrideophyceae and recent molecular analyses clearly establish the validity of this new red algal class and the genus Erythrolobus.

• 한국식품과학회지
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• 제1권1호
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• pp.45-50
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• 1969

자외부흡광 스펙트럼의 변화와 티 비 에이(TBA) 반응으로 살필 때, 수용액의 송에서의 말론알데하이드(malonaldehyde)는 과장 $260m/{\mu}$ 부근의 자외선조명에 의하여 광화학적 변화를 받는다. 이 용액에 아프라톡신(aflatoxin) 을 가하면 파장 $360m/{\mu}$ 부근의 광선에 의해서 이와 같은 변화가 재빨리 일어나며, 또 보통 형광등을 이용한 실험실의 조명에 의해서도 비록 그 변화는 느려지지만 마찬가지로 일어난다. 이과 같은 변화는 비가역적이며, 이 반응에서 아프라톡신은 다만 감광제로서의 역할을 한다. 또 이 반응의 기작은 말론알데하이드 분자의 평행적 이중결합체 형성에 의한 것 같다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.399-400
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• 2008

The light efficiency of fringe-field switching (FFS) mode when using a liquid crystal (LC) with positive dielectric anisotropy was found to be dependent on the magnitude of dielectric anisotropy, such that the lower dielectric anisotropy, the higher. We studied out not only light efficiency but also response time according to dependence on the magnitude of dielectric anisotropy. Rising and decay time became fast and slow respectively according to decreasing the magnitude of dielectric anisotropy. This paper investigates electro-optical characteristic of FFS mode using LC with a positive dielectric anisotropy dependent on the magnitude of dielectric anisotropy of the LC.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.392-393
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• 2007

In this paper, we report the characteristics inorganic EL device with high dielectric constant materials of PMN, PZT. Fabricated EL device shows stable light emission even at 20kHz -400Volt without any break down failure. Brightness voltage curve of EL device is same with typical EL. As increasing applied voltage, the brightness increased linearly. From the results of Frequency and duty ratio variation, over 50% of brightness increment was seen. Luminous efficiency was increased upto 200V range and saturated over 200V by slow increasement of light emission. We got e bright stable emission of 1733 cd/m2 at the condition of Frequency 35 KHz, Duty 10%, 400V.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.70-70
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• 2013

As the costs of carbon-footprinetd fuels grow continuously and simultaneously atmospheric carbon dioxide concentration increases, solar fuels are receiving growing attention as alternative clean energy carriers. These fuels include molecular hydrogen and hydrogen peroxide produced from water, and hydrocarbons converted from carbon dioxide. For high efficiency solar fuel production, not only light absorbers (oxide semiconductors, Si, inorganic complexes, etc) should absorb most sunlight, but also charge separation and interfacial charge transfers need to occur efficiently. With this in mind, this talk will introduce the fundamentals of solar fuel production and artificial photosynthesis, and then discuss in detail on photoelectrochemical (PEC) water splitting and CO2 conversion. This talk largely divides into two section: PEC water oxidation and PEC CO2 reduction. The former is very important for proton-coupled electron transfer to CO2. For this oxidation, a variety of oxide semiconductors have been tested including TiO2, ZnO, WO3, BiVO4, and Fe2O3. Although they are essentially capable of oxidizing water into molecular oxygen, the efficiency is very low primarily because of high overpotentials and slow kinetics. This challenge has been overcome by coupling with oxygen evolving catalysts (OECs) and/or doping donor elements. In the latter, surface-modified p-Si electrodes are fabricated to absorb visible light and catalyze the CO2 reduction. For modification, metal nanoparticles are electrodeposited on the p-Si and their PEC performance is compared.

• 한국육종학회지
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• 제42권4호
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• pp.351-356
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• 2010

Brachypodium distachyon is rapidly emerged in biological study and has been currently used as a model system for genetics and functional studies for crop improvement and biofuel production. Phosphinothricin (PPT) has been widely used as a selectable agent, which raises ammonium content and induces toxicity in non-transformed plant cells. However PPT selection is not much effective on Brachypodium callus consequently reducing transformation efficiency. In order to identify the efficient conditions of PPT selection, calli obtained from mature seeds of Brachypodium (PI 254867) were cultured on the callus inducing medium (CIM) or regeneration medium (ReM) containing serial dilutions of the PPT (0, 2, 5, 10, and 15 mg/l) in dark or light condition. Callus growth and ammonium content of each treatment were measured 2 weeks after the treatment. Although callus growth and ammonium content did not show much difference in CIM, slow callus growth and increased ammonium accumulation were found in ReM. No significant difference of ammonium accumulation in response to PPT was found between dark and light conditions. In order to identify major factors affecting increased ammonium accumulation, callus was cultured on the media in combined with phytohormones (2,4-D or kinetin) and carbon sources (sucrose or maltose) containing with PPT (5 mg/l). The highest ammonium content in callus was found in the kinetin and maltose media.

• BMB Reports
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• 제35권4호
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• pp.389-394
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• 2002

$[Ru(bpy)_2(dppz)]^2+$ (bpy=2,2'-bipyfidine, dppz=dipyrido[3,2-a:2',3'-c]phenazine) (RuBD), a long-lifetime metal-ligand complex, displays favorable photophysical properties. These include long lifetime, polarized emission, but no significant fluorescence from the complex that is not bound to DNA. To show the usefulness of this luminophore (RuBD) for probing the bending and torsional dynamics of nucleic acids, its intensity and anisotropy decays when intercalated into supercoiled and relaxed pTZ18U plasmids were examined using frequency-domain fluorometry with a blue light-emitting diode (LED) as the modulated light source. The mean lifetimes for the supercoiled plasmids (< $\tau$ >=148 ns) were somewhat shorter than those for the relaxed plasmids (< $\tau$ >=160 ns). This suggests that the relaxed plasmids were shielded more efficiently from water. The anisotropy decay data also showed somewhat shorter slow rotational correlation times for supercoiled plasmids (288 ns) than for the relaxed plasmids (355 ns). The presence of two rotational correlation times suggests that RuBD reveals both the bending and torsional motions of the plasmids. These results indicate that RuBD can be useful for studying both the bending and torsional dynamics of mucleic acids.

• 한국진공학회지
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• 제14권3호
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• pp.143-146
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• 2005

본 연구에서는 결맞는 x-선을 이용하여 표면의 거동 현상을 관찰할 수 있는 새로운 실험 방법인 x-선 상관 분광법(x-ray photon correlation spectroscopy)을 소개하고 이를 이용하여 측정한 고분자 박막에서의 거동 현상에 대한 결과를 보고하고자 한다. 이 방법은 파장이 짧은 x-선 영역에 동역학 광산란(dynamic light scattering) 원리를 적용하여 나노 스케일의 동역학 현상을 관찰할 수 있다. 또한 x-선 산란을 이용하므로 동역학 현상과 동시에 구조 특성을 측정할 수 있다. 본 논문에서는 글래스 전이보다 높은 온도에서, 기판에 코팅된 고분자 박막의 표면 거동현상을 온도와 파수의 함수로 측정하였다. 박막의 두께가 두꺼울 때에는 점성이 높은 액체에서와 계산된 이론에서와 같은 표면 거동 현상이 관찰되었고, 얇은 박막에서는 갇힘 현상에 의한 효과를 관찰하였다.

• Applied Microscopy
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• 제45권4호
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• pp.254-258
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• 2015

A histological study on the retina of Misgurnus anguillicaudatus was carried out by light microscopy and scanning electron microscopy as part of getting information about relation between its habitat and visual cells. The visual cells of the retina in M. anguillicaudatus, a bottom-dwelling freshwater pond loach in stagnant or slow waters such as swamps, reservoirs and paddy fields, consists of double cones and large rods. The cones form a row mosaic pattern in which the partners of double cones are linearly oriented with a large rod. In a double cone, the two members are unequal such that one cone may be longer than the other.