• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 2007년도 Proceedings of The Convention
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• pp.117-126
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• 2007

Cosmetics have mild activity on the human body, and intended to be used for cleaning, beautifying the human body, and also keeping healthy skin or hair, promoting attractiveness or altering the appearance. Functional cosmetics, in other words cosmeceuticals, are restricted for following functions: 1) Whiten the skin tone by preventing deposition of melanin pigmentation or lightening of the color of melanin of skin, 2) alleviate or improve wrinkles of the skin, and 3) protect the skin from the ultra violet rays from the sun. According to the functions of the functional cosmetics, skin whitening products, anti-wrinkle products, and suntan & sunscreen products are manufactured. In order to manufacture and import the functional cosmetics in Korea, the approval process in KFDA is necessary. The review process in KFDA is performed based on The Korea Food and Drug Administration Notification 2007-44, "The Regulation of Reviewing the Functional Cosmetics" (June 29, 2007). Only after the approval of KFDA, functional cosmetics are allowed to advertise to the consumers for their functionality.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.429-435
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• 2006

In this study multi-zone modeling program CONTAM 2.4 which is developed by NIST is used for modeling the air disinfection system which is consist of dilution, filtration, ultra violet germicidal irradiation (UVGI) for removing the indoor microorganism such as bacteria and fungus. Developed models those protect occupants against indoor microorganism generated in our daily life are enable to use for immune building simulation tool. Also, results indicate that those models are enable to compute the real situation that is almost impossible of carrying out experiment and identify the disinfection rate with highly reliance. Results also suggest that engineers will use these models as a design tool for the immune building system.

• Journal of the Optical Society of Korea
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• 제17권1호
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• pp.73-80
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• 2013

In the process of lithography using ultra violet light sources for semiconductor devices, most of defects are made by sub-micrometer pollutants generated at photochemical reactions. We proposed and developed a novel vibration-insensitive on-axis interferometer with a sub-micrometer lateral resolution by using the interference between two beams: one scattered from defects and the other reflected from a reference area without defects. The proposed system was successfully demonstrated to detect a small Al defect of 0.5 ${\mu}m$ diameter within the inspection time of less than 30 minutes over the area of the photo-mask which is 6 inch by 6 inch square.

• Current Optics and Photonics
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• 제3권3호
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• pp.243-247
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• 2019

We have developed a compact, wavelength-selectable, Q-switched Nd:YAG laser at mid ultraviolet for chemical warfare agent detection. The fundamental wave at 1064 nm is delivered by a pulsed solid state laser incorporating with a square-type Nd:YAG rod in a resonator closed by two crossed Porro prisms for environmental reliability. The output energy at 213 nm ($5{\omega}$) and 266 nm ($4{\omega}$) by ${\chi}^{(2)}$ process in the sequentially disposed BBO crystals are measured to be 6.8 mJ and 15.1 mJ, respectively. The output wavelength is selected for $5{\omega}$ and $4{\omega}$ by a motorized wavelength switch. The energy ratio of the $5{\omega}$ to the $4{\omega}$ is varied from 0.05 to 0.85 by controlling the phase matching temperature of the nonlinear crystal for sum-frequency generation without change of the output pulse parameters.

• Current Optics and Photonics
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• 제6권4호
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• pp.375-380
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• 2022

We demonstrate two types of light field displays based on waveguide grating coupler arrays: a line beam type and a point source type. Ultra violet imprinting of an array of diffractive nanograting cells on the top surface of a 50-㎛-thin slab waveguide can deliver a line beam or a point beam to a multidirectional light field out of the waveguide slab. By controlling the grating vectors of the nanograting cells, the waveguide modes are externally coupled to specific viewing angles to create a multidirectional light field display. Nanograting cells with periods of 300 nm-518 nm and slanted angles of -8.5°~+8.5° are fabricated by two-beam interference lithography on a 40 mm × 40 mm slab waveguide for seven different viewpoints. It is expected that it will be possible to realize a very thin and flexible panel that shows multidirectional light field images through the waveguide-type diffraction display.

• Journal of Korean Vacuum Science & Technology
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• 제3권2호
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• pp.116-120
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• 1999

Possible role of hydrogen atoms on the formation of microcrystalline silicon films was schematically investigated using a plasma enhanced chemical vapor deposition system. A layer-by-layer technique that can alternate deposition of ${\alpha}$-Si thin film and then exposure of H2 plasma was used for this end. The experimental process was extensively carried out under different hydrogen plasma times (t2) at a fixed number of 20 cycles in the deposition. structural properties, such as crystalline volume fractions and grain shapes were analyzed by using a Raman spectroscopy and a scanning electron microscopy. Electrical transports were characterized by the temperature dependence of the dark conductivity that gives rise to the calculation of activation energy (Ea). Optical absorption was measured using an ultra violet spectrophotometer, resulting in the optical energy gap (Eopt). Our experimental results indicate that both of the hydrogen etching and the structural relaxation effects on the film surface seem to be responsible for the growth mechanism of the crystallites in the ${\mu}$c-si films.

• Advances in nano research
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• 제13권5호
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• pp.437-451
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• 2022

Synthesis approaches usually affect the physical and chemical properties of ferrites. This helps ferrite materials to design them for desired applications. Some of these methods are mechanical milling, ultrasonic method, micro-emulsion, co-precipitation, thermal decomposition, hydrothermal, microwave-assisted, sol-gel, etc. These methods are extensively reviewed by taking example of ZnFe₂O₄. These methods also affect the microstructure and local structure of ferrite which ultimately affect the physical and chemical properties of ferrites. Various spectroscopic techniques such as Raman spectroscopy, Fourier Transform Infrared spectroscopy, Ultra Violet-Visible spectroscopy, Mossbauer spectroscopy, extended x-ray absorption fine structure, and electron paramagnetic resonance are found helpful to reveal this information. Hence, the basic principle and the usefulness of these techniques to find out appropriate information in ZnFe₂O₄ nanoparticles is elaborated in this review.

• 헤리티지:역사와 과학
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• 제54권4호
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• pp.22-35
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• 2021

최근 기후가 급격히 변하고 미세 먼지가 증가하는 등 대기 환경 오염 물질의 양상도 변하고 있다. 이에 따라 채색 문화재에 사용되는 안료의 안정성 연구에 대한 필요성이 대두되고 있다. 회청은 전통 인공 무기 안료로 스몰트(Smalt)라고 불리는 청색의 유리 안료이다. 포타쉬 유리에 코발트를 녹여 만드는데 벽화, 회화 등의 채색 문화재에 사용되어왔다. 본 연구에서는 시판되는 회청 안료 3종을 수집하여 안료의 특성을 분석하였다. 회청은 제조사에 따라 발색 원소인 Co와 융제인 K의 함량에 차이를 보였는데 Smalt-3의 경우 Co 함량이 15.1 wt.%로 가장 적았고, K 함량은 29.6 wt.%로 가장 많았다. 채색 시편을 제작하여 안료의 보존에 영향을 미치는 것으로 알려진 자외선, CO₂/NO₂ 등의 대기 오염 가스, 그리고 미세 먼지에 이온 상태로 존재하는 염(NaCl) 등 주요 환경 인자에 대한 안정성을 평가하였다. 색 안정성에 영향을 미친 인자는 NO₂ 가스, 자외선, 수용성 염(NaCl)이며 이 중 NO₂ 가스가 색 변화에 가장 큰 영향을 미친 것으로 나타났다. 성분 분석 결과, 안료의 색 변화에 K와 Co의 함량이 영향을 미치는 것을 확인할 수 있었으며, Smalt-3은 NO₂와 수용성 염(NaCl)에서 색의 안정성이 가장 취약하였다. 특히 수용성 염(NaCl)은 색 변화에도 작용하지만 이보다 채색층 표면 물성을 약화시켜 채색층 도막 안정성에 악영향을 미치는 것을 본 연구를 통해 확인하였다. 반면 CO₂ 가스에 노출된 시편들은 색상 및 성분에 큰 변화가 없었다. 따라서 CO₂를 제외하고 시험에 적용된 모든 환경 인자가 회청의 색상을 변화시키고 도막의 안정성도 저해한다는 것을 알 수 있었다.

• 미생물학회지
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• 제20권3호
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• pp.125-133
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• 1982

Mutational experiments were performed to imporve the cellulase productivity of Aspergillus phoenicis KU175, isolated from the southern part of Korea, as a high cellulase producer. By treatment ultra-violet light nad 4-NQO(4-Nitroquinoline-N-Oxide), mutation waas induced, and treatment ultra-violet light and 4-NQO (4-Nitroquinoline-N-Oxide), mutation was induced, and A.phoenicis KU175-115 was finally selected for its highest avicelase production. Avicelase production of the mutant was increased about 2 times compared with those of the wild strain. However, activities of other hydrolytic enzymes, such as amylase, protease and nuclease, of the mutant strain didn't show a marked difference compared with those of the nuclease, of the mutant strain didn't show a marked difference compared with the wild strain, except slight increase in ribonuclease activity and slight decrease in glucoamylase activity. Avicelases from the mutant strain selected were purified from wheat bran culture by successive salting out, followed by dialysis and column chromatography, and their charcteristics were compared with thosw of the wild strain. Avicelase was separated into three peaks in the mutant strain as well as in the case of wild strain. Avicelase II activity of the mutant strain was prominently higher than that of the wild strain, while avicelase I and III activities of those were equivalent. The optimal pH ranges and stability of avicelase II from the mutant strain were pH4-5 and pH3.5-6.0, respectively, as well as in the case of the wild strain. The optimal temperature and thermal stability of avicelase II from the mutant strain were $40{\sim}50^{\circ}C\;and\;20{\sim}55^{\circ}C$, respectively. These results were same as those of the wild strain. By the using of Eadie-Hofastee plot, $K_m\;and\;V_{max}$ of avicelase II from the mutant and the wild strain were calculated to be 2.29mg/ml and $4.84{\mu}g$ reducing sugar as glucose per min equally, from the line fitted to the data by the least square method. Activity of avicelase II from the mutant strain was slightly activated by $Mg^{++}\;but\;inhibited\;by\;Cu^{++}, \;Mn^{++}\;and\;Zn^{++}$, as well as in the case of the wild strain. Therefore, it was concluded that the mutant didn't induce the formation of another avicelase isozyme, or the changes in the properties of avicelase, but induce the changes in the productively of the same avicelase II by the action of regulatory gane.

• 한국안광학회지
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• 제13권1호
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• pp.71-76
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• 2008

목적: 저온에서 열처리에 의해 소다-라임-실리카 유리 위에 강한 UV방사 나노결정 ZnO박막을 단순하고 효율적 방법으로 개선하고자 한다. 방법: 소다-라임-실리카 유리 위에 코팅되고 전열처리 및 300$^{\circ}C$의 후열처리를 행하여 제조된 나노 결정질 ZnO 박막의 결정 구조적, 표면 형상적 및 광학적 특성을 X-선 회절 분석, 전계방사 주사형 전자 현미경, 원자간력 현미경, ultra violet - visible - near infrared spectrophotometer 및 photoluminescence를 이용하여 분석하였다. 결과: 가시광 영역에서 높은 투과율과 자외부에서 뚜렷한 흡수밴드를 갖는 c-축으로 고배향된 ZnO 박막을 300$^{\circ}C$의 후열처리를 통하여 얻을 수 있었다. 비교적 뚜렷한 near band edge 발광을 보이는 photoluminescence 스펙트럼이 나타났으며, 결함에 의한 완만한 녹색 발광은 거의 관찰되지 않았다. 결론: 앞으로 본 연구는 300$^{\circ}C$ 이하의 저온에서 저렴하고 쉽게 ZnO을 기초로한 광전기 소자에 적용될 것이다.