• Title/Summary/Keyword: Light absorber

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A Study on the Friction Welding of SM45C/SM20C-Pipe which Used in the Light Piston-Rod (경량화 쇽업소바 피스톤로드에 사용되는 SM45C/SM20C-Pipe의 마찰용접에 관한 연구)

  • Min, Byung-Hoon;Choi, Su-Hyun;Kang, Jeong-Sik;Lee, Hyung-Ho;Min, Taeg-Ki
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.17 no.4
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    • pp.42-50
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    • 2008
  • Various researches to reduce weight of a vehicle are achieving. One of these researches is tendencious to manufacture the hollow piston rod using friction welding instead of solid one of the vehicle shock absorber. This study deals with the friction welding of SM45C to SM20C-pipe that is used normally in the vehicle shock absorber. The friction time was variable conditions under the conditions of spindle revolution of 2,000rpm, friction pressure of 55MPa, upset pressure of 75MPa, and upset time of 2.0seconds. Under these conditions, the microstructure of weld interface, tensile fracture surface and mechanical tests of friction weld were studied and so the results were as follows. When the friction time was l.5seconds under the conditions, the maximum tensile strength of the friction weld happened to be 837MPa, which is 113% of SM20C's tensile strength and 97% of SM45C's. The optimal welding conditions were n=2,000rpm, $P_1=55MPa$, $P_2=75MPa$, $t_1=1.5sec$, $t_2=2.0sec$ when the total upset length is 1.7mm.

The effect and stability of plant extract ingredient as uv absorber (자외선 흡수제로서의 식물추출성분의 안정성과 효과)

  • 김경동;이용두;박성순;윤성화;이석현
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.26 no.1
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    • pp.41-58
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    • 2000
  • Recently the harmfulness of W radiation is in creasing due to encironmental pollution. Environmental population may also play a role in global decrease of ozone layer, A major consequence of ozone depletion is increase in solar ultra violet radiation received at the earth's surface excessive exposure to W radiation cause a lot of problems in our skin. Plant extract that possess antioxidative activities has been reported to retard the oxidation process in product to which they have been added. Plant are alived under solar light. So it is expect the plants have so many protection mechanisms and UV absorbent ingredients against ultra violet radiation such as UVB, UVA. Plant extract which were flavonoids, alkaloids and others could be transformed into UV absorber by chemical modification. Therefore with the aim of finding alternative natural absorber that can safely be used in cosmetic, we have screened various extract for their UV absorbent effect. Thus, the cosmetic safety against human skin, antimicrobial effects and others could be improved by using the silicon.

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A Study on Monte Carlo Simulation in Resin of New Austria Tunnel Method by admixture for Shrinkage Compensating Concrete (무수축 콘크리트 혼화제를 활용한 New Austria Tunnel Method 수지에서 Monte Carlo 시뮬레이션에 관한 연구)

  • Kim, Ki-Jun;Sung, Wan-Mo;Kim, Joo-Han;Jung, Hyung-Hak
    • Journal of the Korean Applied Science and Technology
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    • v.34 no.1
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    • pp.125-131
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    • 2017
  • The influences of scatterer and absorber in turbid material by light scattering in concrete admixture were interpreted for the scattered intensity and wavelength. The molecular properties have been studied by Monte Carlo simulation in resin of New Austria Tunnel Method. It has been found that the effects of optical properties in scattering media could be investigated by the optical parameters(${\mu}_s$, ${\mu}_a$,${\mu}_t$). Monte Carlo Simulation method for modelling of light transport in the civil engineering and construction field was applied. The results using a phantom were discussed that the admixture for shrinkage compensating concrete in NATM-rasin from source to detector is measured, and scattering intensity is stronger with those obtained through Monte Carlo Simulation. It may also aid in designing the best model for coatings and corrosion for the durability of metal constructions.

A Study on Monte Carlo Simulation by Beam Scattering in Resin of New Austria Tunnel Method for Safety of Industrial Disaster (산업재해 안전을 위한 New Austria Tunnel Method 수지에서 빔산란에 관한 Monte Carlo 시뮬레이션에 관한 연구)

  • Kim, Ki-Jun;Lee, Joo-Youb
    • Journal of the Korean Applied Science and Technology
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    • v.29 no.3
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    • pp.473-479
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    • 2012
  • The influences of scatterer and absorber in turbid material by light scattering were interpreted for the scattered intensity and wavelength. The molecular properties have been studied by Monte Carlo simulation in resin of New Austria Tunnel Method. It has been found that the effects of optical properties in scattering media could be investigated by the optical parameters(${\mu}_s$, ${\mu}_a$, ${\mu}_t$). Monte Carlo Simulation method for modelling of light transport in the civil engineering and construction field was applied. The results using a phantom were discussed that the distance from source to detector is closer, and scattering intensity is stronger with those obtained through Monte Carlo Simulation. It may also aid in designing the best model for coatings and corrosion for the durability of metal constructions.

Preparation of methylammonium lead halide perovskite thin films by dual feed ultrasonic spray method (이중주입 초음파분무법에 의한 메틸암모늄 할로젠화 납 페로브스카이트 박막의 제조)

  • Kim, Rock Yoon;Kim, Tae Huei;Park, Kyung Bong
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.29 no.1
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    • pp.6-11
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    • 2019
  • Methylammonium lead halide ($MAPbX_3$, X = I, Br) thin films, used as the light absorber of perovskite solar cells, were prepared using the dual feed ultrasonic spray method. Going through a deposition at a substrate temperature of below $60^{\circ}C$ and then a final heat treatment at $75^{\circ}C$ for 5 minutes using dual feed ultrasonic spray method, $MAPbI_3$ single phase could be formed. Whereas undergoing a deposition at temperatures above $80^{\circ}C$, the spheroidal grains could be changed into rod-shaped fractal structures due to the decomposition of the perovskite phase. Furthermore, using the same method at a higher heat treatment temperature of $100^{\circ}C$, $MAPbI_{3-x}Br_x$ thin films could also be formed from $MAPbI_3$ and $MAPbIBr_2$ solution.

Risk Assessment of Drometrizole, a Cosmetic Ingredient used as an Ultraviolet Light Absorber

  • Lee, Jae Kwon;Kim, Kyu-Bong;Lee, Jung Dae;Shin, Chan Young;Kwack, Seung Jun;Lee, Byung-Mu;Lee, Joo Young
    • Toxicological Research
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    • v.35 no.2
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    • pp.119-129
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    • 2019
  • As the use of cosmetics has greatly increased in a daily life, safety issues with cosmetic ingredients have drawn an attention. Drometrizole [2-(2'-hydroxy-5'-methylphenyl)benzotriazole] is categorized as a sunscreen ingredient and is used in cosmetics and non-cosmetics as a UV light absorber. No significant toxicity has been observed in acute oral, inhalation, or dermal toxicity studies. In a 13-week oral toxicity study in beagle dogs, No observed adverse effect level (NOAEL) was determined as 31.75 mg/kg bw/day in males and 34.6 mg/kg bw/day in females, based on increased serum alanine aminotransferase activity. Although drometrizole was negative for skin sensitization in two Magnusson-Kligman maximization tests in guinea pigs, there were two case reports of consumers presenting with allergic contact dermatitis. Drometrizole showed no teratogenicity in reproductive and developmental toxicity studies in which rats and mice were treated for 6 to 15 days of the gestation period. Ames tests showed that drometrizole was not mutagenic. A long-term carcinogenicity study using mice and rats showed no significant carcinogenic effect. A nail product containing 0.03% drometrizole was nonirritating, non-sensitizing and non-photosensitizing in a test with 147 human subjects. For risk assessment, the NOAEL chosen was 31.75 mg/kg bw/day in a 13-week oral toxicity study. Systemic exposure dosages were 0.27228 mg/kg bw/day and 1.90598 mg/kg bw/day for 1% and 7% drometrizole in cosmetics, respectively. Risk characterization studies demonstrated that when cosmetic products contain 1.0% of drometrizole, the margin of safety was greater than 100. Based on the risk assessment data, the MFDS revised the regulatory concentration of drometrizole from 7% to 1% in 2015. Under current regulation, drometrizole is considered to be safe for use in cosmetics. If new toxicological data are obtained in the future, the risk assessment should be carried out to update the appropriate guidelines.

The Effect of Three-Dimensional Morphology with Wet Chemical Etching in Solar Cells

  • Kim, Hyunyub;Park, Jangho;Kim, Hyunki;Kim, Joondong
    • Proceedings of the Korean Vacuum Society Conference
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    • 2013.02a
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    • pp.667-667
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    • 2013
  • Optimizing morphology of the front surface with three dimensional structures (3D) in solar cell is essential element for not only effectivelight harvesting but also carrier collection and separation without the cost burden in process. We designed a three-dimensionally ordered front surface with wet chemical etching. Wet chemical etching is a proper way to have three dimensional structures. The method efficiently transmits the incident light at the front surface to a Si absorber and has competitive price in manufacturing when comparing with reactive ion etching (RIE) to have three dimensional structures. This indicates that optimized front surface with three dimensional structures by wet chemical etching will bring effective light management in solar cells.

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Penetration depth and Wave Propagation in Random Media (무질서한 매질에서 침투깊이와 파동 전파)

  • Kim, Ki-Jun;Sung, Ki-Chun
    • Journal of the Korean Applied Science and Technology
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    • v.23 no.1
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    • pp.70-76
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    • 2006
  • The influence of fluorophor, scatterer, absorber in turbid materials by light scattering were interpreted for the scattered fluorescence intensity and wavelength, it is studied the molecular property by laser induced fluorescence spectroscopy. It can be found that the effects of optical property are penentrated in scattering media by the optical $parameters({\mu}s$, ${\mu}a$, ${\mu}t$, ${\gamma}$, ${\rho})$. The value of scattering coefficient ${\mu}s$ is large appeared by means of the increasing particles of scattering, it can be found that the slope appears exponentially as a function of distance from laser source to detector. It may also utilize in designing the best model for oil chemistry, laser medicine and application of medical engineering.

Photodegradation of Paper Treated by Photostabilizer (광안정제(光安定劑)를 처리(處理)한 종이의 광열화(光劣化))

  • Kim, Bong-Yong
    • Journal of the Korean Wood Science and Technology
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    • v.23 no.3
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    • pp.23-27
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    • 1995
  • Several characteristic results of physical and optical properties of paper treated by UV light were obtained in the previous papers(Kim et al. 1988). In this paper, folding endurance and brightness of paper prepared by spraying photostabilizer were examined in order to elucidate photodegradation phenomena, UV light absorber and radical scavenger were most effective in preventing of folding endurance decrease. These results may be indicated that depolymerization of cellulose and hemicellulose chains leading to degradation of paper mechanical properties mainly caused by radical reaction. Ineffective hydroperoxide decomposer may be explained because of auto-oxidation reactions before forming stable compound from hydroperoxide.

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Studies on the Measurements of Optical Parameters in Turbid Material by Light Scattering (혼탁 매질에서 광산란에 의한 광학적 파라미터들의 측정에 관한 연구)

  • Kim, Ki-Jun;Sung, Ki-Chun
    • Journal of the Korean Applied Science and Technology
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    • v.12 no.2
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    • pp.151-156
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    • 1995
  • The influences of fluorophor, scatterer, absorber in turbid material by light scattering were interpreted for the scattered fluorescence intensity and wavelength, it has been studied the molecular properties by laser induced fluorescence spectroscopy. It has been found that the effects of optical properties in scattering media by the optical parameters(${\mu}_{s}$, ${\mu}_{a}$, ${\mu}_{t}$). The value of scattering coefficient ${\mu}_{s}$ is large by means of the increasing particles of scatterer, it has been found that the slope decays exponentially as a function of distance from laser source to detector. It may also aid in designing the best model for oil chemistry, laser medicine and application of medical engineering.