• Environmental Analysis Health and Toxicology
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• 제29권
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• pp.16.1-16.9
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• 2014

Objectives Rapid increase in engineered nanoparticles (ENPs) in many goods has raised significant concern about their environmental safety. Proper methodologies are therefore needed to conduct toxicity and exposure assessment of nanoparticles in the environment. This study reviews several analytical techniques for nanoparticles and summarizes their principles, advantages and disadvantages, reviews the state of the art, and offers the perspectives of nanometrology in relation to ENP studies. Methods Nanometrology is divided into five techniques with regard to the instrumental principle: microscopy, light scattering, spectroscopy, separation, and single particle inductively coupled plasma-mass spectrometry. Results Each analytical method has its own drawbacks, such as detection limit, ability to quantify or qualify ENPs, and matrix effects. More than two different analytical methods should be used to better characterize ENPs. Conclusions In characterizing ENPs, the researchers should understand the nanometrology and its demerits, as well as its merits, to properly interpret their experimental results. Challenges lie in the nanometrology and pretreatment of ENPs from various matrices; in the extraction without dissolution or aggregation, and concentration of ENPs to satisfy the instrumental detection limit.

• Fisheries and Aquatic Sciences
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• 제15권2호
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• pp.163-168
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• 2012

The non-utilized biomass of the aquacultured seaweed Undaria pinnatifida, particularly the rhizoid, is an alternative source of arachidonic acid (AA). Of the five aquacultured kelps that were tested, U. pinnatifida yielded the highest amount of AA, which was isolated from the rhizoids. Its identity (C20:4 n-6) was confirmed from gas chromatography-mass spectrometry spectral data. The optimal conditions for post-harvest storage or pretreatment of the rhizoids in Provasoli's enriched seawater for AA extraction were determined to be pH 7.8, 2% $CO_2$-enriched air, 20 ${\mu}mol\;m^{-2}\;s^{-1}$ light, and $10^{\circ}C$. Under these conditions, the AA content after 1 day of storage was enhanced by up to 127%. In the absence of light under ambient aeration, the AA content after 1 day of storage diminished to 90%. Rhizoids collected late in the season (April and May) contained the highest amounts of AA (approximately 2.5 mg/g tissue).

• 한국광학회지
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• 제13권2호
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• pp.155-161
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• 2002

혼탁매질인 손톱의 하부면에는 개인별로 상이한 융선과 곡 구조의 패턴인 조상(爪床, nail bed)이 있다. 이중 융선에는 혈액이 흐르는 모세혈관 고리(capillary loop)가 밀집되 있고 융선과 융선은 모세혈관 고리가 밀집되 있지 않은 골로 구분되어 있다. 670nm 파장의 레이저 빛은 피부의 진피(dermis)에서 산란특성을 가지며 혈액에는 강하게 흡수된다. 손톱하부면 조상(nail bed)의 이와 같은 생체-광학적 특성에 착안하여 혼파매질인 손톱하부면에 위치하는 조상(nail bed) 패턴을 얻어내는 콘포칼 광 스케닝(confocal optical scanning) 구조를 특징으로 하는 광학계를 제안한다. 그리고 이를 이용하여 개인별로 상이한 조상(nail bed) 패턴을 추출해 조상(nail bed) 패턴간의 correlation를 구해 비교함으로써 개인을 구별해내는 개인인증 기법을 제안한다.

• Advances in nano research
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• 제2권1호
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• pp.23-56
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• 2014

The significant growth of the Si photovoltaic industry has been so far limited due to the high cost of the Si photovoltaic system. In this regard, the most expensive factors are the intrinsic cost of silicon material and the Si solar cell fabrication processes. Conventional Si solar cells have p-n junctions inside for an efficient extraction of light-generated charge carriers. However, the p-n junction is normally formed through very expensive processes requiring very high temperature (${\sim}1000^{\circ}C$). Therefore, several systems are currently under study to form heterojunctions at low temperatures. Among them, carbon nanotube (CNT)/Si hybrid solar cells are very promising, with power conversion efficiency up to 15%. In these cells, the p-type Si layer is replaced by a semitransparent CNT film deposited at room temperature on the n-doped Si wafer, thus giving rise to an overall reduction of the total Si thickness and to the fabrication of a device with cheaper methods at low temperatures. In particular, the CNT film coating the Si wafer acts as a conductive electrode for charge carrier collection and establishes a built-in voltage for separating photocarriers. Moreover, due to the CNT film optical semitransparency, most of the incoming light is absorbed in Si; thus the efficiency of the CNT/Si device is in principle comparable to that of a conventional Si one. In this paper an overview of several factors at the basis of this device operation and of the suggested improvements to its architecture is given. In addition, still open physical/technological issues are also addressed.

• Journal of the Optical Society of Korea
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• 제17권3호
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• pp.249-254
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• 2013

In ophthalmology, a pupillometer, a device to measure the diameter of the pupil of the eye, can provide information on the function of the autonomic nervous system. The current pupillometers on the market are either too large to be a handheld instrument, or relatively expensive. In this study, a pupillometer based on a smartphone was designed. Both white and infrared LEDs and a 3M pixel camera of a smartphone were applied for the visual stimuli to an eye and for the acquisition of the eye images, respectively. Contrary to the existing method of pupil measurement that usually observe the variation of pupil diameter, the proposed algorithm in this study was applied to calculate the constriction ratio of the pupillary area in response to pupillary light reflex. The results showed that the constriction ratio of the pupillary area were all in the normal range (above 4.0) from the sixteen healthy participants. It is believed that the approach to pupil measurement used in this study is suitable for a mobile interface, and this system can be applied to clinical research, home-use healthcare, and distributed to some areas which suffer from problems like a lack of medical support.

• 대한의생명과학회지
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• 제8권1호
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• pp.13-20
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• 2002

Asadisulphide were purified from Ferrula assafoetida by organic solvent extraction and chromatography. Since ethyl acetate extracts of F. assafoetida has the strongest inhibitory effects on adherence of HL-60 cells, it was reextracted with ethyl acetate, hexane, and ethyl ether and chromatographed three times to isolate asadisulphide. HL-60 cells were grouped into untreated control, TPA-treated, asadisulphide-teated and TPA＋asadisulphide-treated groups, and structural changes of these cells were observed using light microscope, scanning electron microscope and transmission electron microscope to examine the inhibitory effects of asadisulfide on the TPA-induced adherence of HL-60 cells. Light microscopic observations showed that asadisulphide has inhibitory effects on the cell aggregation, extention of cytoplasmic processes and inhibition of substrate adhesion of HL-60 cells. Using scanning and transmission electron microscope, it was observed that cell surfaces and several ultrastructures of TPA-treated HL-60 cell were different from control group, while there were no remarkable differences between asadisulphide-treated and TPA＋asadisulphide-treated group. These results could suggest that asadisulphide has the inhibitory effects on the TPA-induced structural changes of HL-60 cells.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.251.1-251.1
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• 2014

Oraganic Light Emitting Diodes (OLED) 소자의 광추출 효율을 향상시키기 위한 방안으로 나노급 사이즈의 고 굴절률 패턴을 기판의 내부 패턴에 적용하였다. 100 nm 및 300 nm의 직경을 갖는 Si3N4 나노 패턴을 나노 임프린트 리소그래피와 건식 식각 공정을 통하여 OLED의 유리기판에 형성을 하였다. 그리고 Silicon On Glass (SOG) 물질을 패턴이 전사된 기판에 스핀 코팅으로 평탄화 공정을 진행 함으로써 OLED소자의 전기적인 특성이 떨어지는 문제점을 개선하였다. 그러고 나서 Si3N4 나노 패턴이 형성되고 평탄화 공정을 마친 기판상 OLED 소자를 제작하였다. OLED의 발광층에서 발생한 빛은 Si3N4 나노패턴에 의해 산란되어 광 추출 효율을 개선할 수 있다. 본 연구에서 두 가지 종류 100nm, 300nm 높이의 Si3N4 나노패턴으로 높이에 따른 광 추출 효율을 비교하고자 OLED 소자를 제작하였다. 기판에 Si3N4 패턴이 형성된 OLED의 효율은 Si3N4 300nm에서 13.1% 증가하였다.

• 한국농촌생활과학회지
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• 제8권2호
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• pp.83-91
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• 1997

In this study, the dyeability of natural dye extracted from chesnut shell was investigated in order to explore the using of discarded chesnut shell in natural dyeing. Dyeing experiments were done in various dyeing conditions which were different in dyeing temperature, concentration of dyebath, dyeing time, repitition of dyeing. pH of dyebath and mordant with 3 kinds of experimental fabrics silk, nylon and cotton. Color and color difference ($\Delta$ E) of every dyed fabrics were measured and color fastness to drycleaning, washing, perspiration and light were measured. The results were as follows ; 1. The dyebath became thicker with time and temperature of extraction and the characteristics of dyebath prepared chesnut shell 1g : distilled water 30㏄ after 3 hrs-boiling were 32,400ppm and 3.7pH. 2. The dyeabilities of silk and nylon fabrics were good and color difference was increased with dyeing temperature, concentration of dyebath, dyeing time, number of repitition and acidity of dyebath. But the dyeability of cotton was very poor compared to silk and nylon. 3. Without the treatment of mordant, the dyeability of silk was little lower than that of nylon, but after the treatment of mordants it became higher than nylon. After the treatment of mordant Cu and Fe, the dyeability of cotton was increased although the natural dye from the chesnut shell was hardly absorved in cotton without mordant. 4. On the whole, the colorfastness of dyed silk and nylon were very good except the colorfastness to washing in silk and the colorfastness to light in nylon.

• 한국염색가공학회지
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• 제22권3호
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• pp.207-213
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• 2010

Natural dyeing of Sangju silk for graveclothes with mulberry extract solution was studied. The anthocyanidin dye in the extracted mulberry solution was markedly influenced by pH condition, which resulted in the changed maximum light absorption from a $\lambda$max of 525nm in acidic condition to 380nm in alkaline condition possibly due to the irreversible transformation of anthocyanidin to cyanidin form of the dye. The color fastness properties to both light and washing were good when the fabrics were dyed at $80^{\circ}C$ with the mulberry-extracted solution upto twice extraction.

• Current Optics and Photonics
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• 제2권4호
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• pp.348-355
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• 2018

How to measure the creepage distance of an insulator quickly and accurately is a problem for the power industry at present, and the noticeable concern is that the high voltage insulation equipment cannot be measured online in the charged state. In view of this situation, we develop an on-line measurement system of creepage distance for high voltage insulators based on binocular stereo vision. We have proposed a method of generating linear structured light using a conical off-axis mirror. The feasibility and effect of two ways to solve the interference problem of strong sunlight have been discussed, one way is to use bandpass filters to enhance the contrast ratio of linear structured light in the images, and the other way is to process the images with adaptive threshold segmentation and feature point extraction. After the system is calibrated, we tested the measurement error of the on-line measurement system with a composite insulator sample. Experimental results show that the maximum relative error is 1.45% and the average relative error is 0.69%, which satisfies the task requirement of not more than 5% of the maximum relative error.