• Journal of the Society of Cosmetic Scientists of Korea
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• v.37 no.2
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• pp.137-141
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• 2011

Sunscreen is divided into the organic agent of UV absorption and inorganic agent of reflection. These are evaluated by sun protection factor (SPF) in-vivo test requiring high cost and time, while in-vitro tests are adopted commonly because of short test time, easy result collection. Generally, test method of SPF use SPF 290a by UV-vis spectrometer. The evaluate by SPF 290 has low reproducibility. Although analysis using UV-vis spectrometer has high reproducibility, it is hard to separated results of transmission, adsorption, and reflection. In this study, suggested method of elipsometer has some merit such as high reproducibility, easy separation of transmission/adsorption/re- flection, analysis using various incident angle. We tested the validity of elipsometer for SPF measurement, using commercially available sun-block (SPF 50).

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.111-111
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• 2012

In this talk, we represent a novel approach to investigating intra-nanorod surface plasmon coupling with control over block compositions. The multi-component rod-like nanostructures, which consist of optically active components (Au and Ag) and optically less active component (for example, Ni) in UV-vis-NIR spectral window, showed interesting optical response depending on each block length and the total length of the structure. By controlling the composition and relative lengths of the blocks that comprise these structures, we can tailor the overall optical properties. Depending on the relative fraction of Au and Ag blocks, the intensity of the transverse modes varied without noticeable peak shifts. However, the strong intraparticle surface plasmon coupling resulted in the collective appearance of longitudinal LSP modes, including higher-order modes. The experimental observations were confirmed by theoretical calculation, using a discrete dipole approximation method. In addition, we will briefly discuss how single nanorod solar cells can be synthesized by using by using electrochemical deposition and AAO hard templates.

• Bulletin of the Korean Chemical Society
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• v.22 no.7
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• pp.727-731
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• 2001

Conjugated-non-conjugated alternating block copolymers containing distyrylarylene units were synthesized via Wittig reaction for chemiluminescent fluorophores. The polymers were differentiated from others by the presence of aromatic unit in the chromophoric block. When UV-VIS, photoluminescence and chemiluminescence spectra of these materials were compared with copolymers, a strong bathochromic effect was observed. A more pronounced red shift and higher chemiluminscence efficiency were observed in the polymer with anthracene ring. Sodium salicylate-catalyzed reaction of bis(2-carbopentyloxy-3,5,6-trichlorophenyl) oxalate with hydrogen peroxide produced a strong chemiluminescence from blue to yellow-green light emission with wavelength of 450-537 nm in the presence of the fluorophore. The chemiluminescent intensity decayed exponentially. The glow of chemiluminescence maintained more than l2 hr and was visible with the naked eye.

• Korean Journal of Food Science and Technology
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• v.44 no.5
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• pp.634-637
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• 2012

In strawberry production, among others, the high incidence of diseases by pathogenic fungi resulting in the reduction of fruit yield and quality requires the development of eco-friendly management systems rather than chemical sprays to control them. The diameter of colonies grown in media at $25^{\circ}C$ for 5 days was measured to evaluate the in vitro inhibition of mycelial growth of 5 pathogenic fungi by irradiation with ultraviolet (UV-C, 264 nm). The mycelial growth of 5 pathogenic fungi was inhibited in potato dextrose agar (PDA) by the irradiation of UV-C for 1 hour a day, and was dramatically inhibited by the irradiation of UV-C for 9-12 h a day. The irradiation of UV-C for 9-12 h a day inhibited completely the growth of the late blight pathogen, Phytophthora cactorum. The irradiation distance of 40 to 50 cm was effective for the inhibition of mycelial growth of fungi. The mycelial growth of fungi without pre-incubation was inhibited strongly by UV-C irradiation compared to fungi pre-incubated for 2 days without light. The mycelia growth of Colletotrichum gloeosprioides and Fusarium oxysporum was inhibited strongly by UV-C irradiation in vegetable 8 juice agar compared to PDA.

• Journal of the Korean Chemical Society
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• v.59 no.3
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• pp.257-262
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• 2015

• Journal of the Korean Chemical Society
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• v.58 no.5
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• pp.490-495
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• 2014

• Proceedings of the IEEK Conference
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• 2002.06d
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• pp.243-246
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• 2002

The proliferation of digitized media(audio, image and video) is creating a processing need for copyright enforcement schemes that protect copyright ownership. we argue that a watermark must be placed in perceptually significant components of a signal if it is to be robust to signal distortions and malicious attack. In this paper, RGB coordinate image is transformed into LUV coordinate, it include the characteristics of, Human vision and then the UV component is transformed into NxN block DCT transform. we propose a technique for embedding the watermark of visually recognizable mark into the middle frequency domain of image.

• Journal of the Korean Chemical Society
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• v.55 no.2
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• pp.308-312
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• 2011

• Journal of Adhesion and Interface
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• v.12 no.3
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• pp.81-87
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• 2011

In this study, UV curing and crosslinking process was introduced for synthesis of acrylic foam tape that can be applied to the the automotive assembly process. Polymerized adhesive are laminated to baseform and varying the thickness of specimens were prepared. To measure basic mechanical properties, stainless steel was used. And in the test peel, dynamic shear and t-block were used. The acrylform adhesive show better results compare with typical adhesive and the properties depand on external factors - thick, wetting time -. To analysis functions of acrylic foam adhesive used to automobile production, evaluate the adhesive properties on the various plastic substrate. In PP and PE are categorized low surface energy materials, their properties have not been expressed. But dynamic shear tests show that some properties could be expressed by the difference break mechanism.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.2
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• pp.121-131
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• 2014

Due to the high UV light scattering effect of Zinc oxide (ZnO), it is frequently used in sunscreen skincare products. Recently ZnO coated with silica has been used in cosmetics to improve UV protection, texture, decreased photocatalytic activity, dispersibility and stability of the skin care product. In this study, we developed a ZnO composite powder coated with silica for the future application to skincare products to block UV rays that could cause photoaging. To improve consumer's satisfaction rating, we used ZnO microparticles which are widely used in the cosmetics industry. The silica was coated using hydrothermal method with sodium silicate and acid hydrolysis. UV protection of the composite powder was analyzed by UV-Vis and in-vitro test and the advantages for practical use of this powder as a skincare product were determined.