• Journal of Pharmaceutical Investigation
• /
• 제39권2호
• /
• pp.121-125
• /
• 2009

The objective of this study was to investigate the feasibility of applying the Intense Pulsed Light (IPL) as a tool to enhance the skin absorption of arbutin, a well-known skin-whitening agent. Arbutin solution or skin formulation was applied on the back of hairless mouse skin in vivo after IPL treatment, and then the skin deposition of arbutin was determined by HPLC. IPL treatment significantly increased the amount of arbutin in the skin after 6 hours when arbutin solution was applied 20 times. IPL also enhanced the skin deposition of arbutin when arbutin formulation was applied, although it was not significantly different. Significant increase of surface skin temperature was observed by IPL treatment, which might be a mechanism of the enhanced skin absorption of arbutin. These results suggest the feasibility of using IPL as a tool to increase the skin absorption of whitening agents, although further research needs to be conducted to understand its exact mechanism.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
• /
• pp.533-536
• /
• 2006

A light-weight aggregate with a surface layer was fabricated using glass abrasive sludge and expanding agents. The glass abrasive sludges were mixed with expanding agents ($Fe_2O_3,\;graphite,\;CaCO_3$) and formed into precursors. These precursors were sintered in the range of $700-900^{\circ}C$ for 20min. The sintered light-weight aggregate had a surface layer with smaller pores and an inner region with larger pores. The surface layer and pores controlled the water absorption ratio and physical properties. As the expanding agent fraction and the sintering temperature increased, the porosity and pore size increased. The light-weight aggregate with $Fe_2O_3$ and graphite as the expanding agents had a low water absorption ratio while the porous material with $CaCO_3$ as the expanding agent had a higher water absorption ratio and more open pores.

• 대한치과기공학회지
• /
• 제33권4호
• /
• pp.291-297
• /
• 2011

Purpose: The purpose of this study was to know the availability of three photosensitizers, CQ, PD, DA, as a photosensitizer of dental resin composite. We want to know abortion band around visible light region for the using potential possibility as a photosensitizer for visible light cured dental composite resin. And I studied to know the relative photodecomposition ratio of three photosensitizers with or without photoinitiator, DAEM. Methods: The photodecomposition of three photosensitizers were studied by UV absorption spectroscopy in ethanol and determined by same instrument with irradiation time for relative photodecomposition. In order to study the effect of amine on photodecomposition was added the DAEM in the photosensitizer solution and the relative rate was measured by the same procedure with aove mentioned. Results: The all of three photosensitizers are absorbed around visible light region. The relative rate of decrease in absorbance incereased in the order: CQ < BD < PD. The effect of DAEM on the photodecomposition of the photosensitizers was appeared different results without DAEM. The photodecomposition rate of PD and DA decreased somewhat with the addition of amine, while that of CQ increased. The rtealtive photodecomposition rate increased in the oprder: BD ${\leq}$ CQ < PD with the addition of amine, but the differnce was not significant. Conclusion: PD and DA like CQ gives to the possibility of use as a photosensitizer for visible light cured dental composite resin by absorption around visible light region and photodecomposition in the maximum absorption wavelength. And it is showed that PD and DA are not effective decomposed with amine initiator, DAEM but CQ decomposed with DAEM effectively. This result may be due to a different mechanism operating for the decomposition of photosensitizers in the presence of amine.

• 한국조경학회지
• /
• 제29권6호
• /
• pp.92-100
• /
• 2002

This study was carried out to obtain fundamental information on the growth response of interior landscape plants under fluorescent light, sunlight and optical fiber lighting indoors. Saintpaulia ‘Delaware’, ‘Kalanchoe blossfeldiana, Anthurium scherzerianum and Ardisia crenata were examined using light intensity of 5001ux and 1,0001ux of fluorescent light, sunlight and optical fiber lighting in an interior environment. Results of experiments are as follows; 1) Plant growth status showed the best results under optical fiber lighting compared with fluorescent light or sunlight. 2) Plant growth status was better under 1,0001ux light intensity than 5001ux light intensity and in cases of the same light intensity, the highest growth increase was under optical fiber lighting. while it was showed relatively different according to the different plant species between a fluorescent light and sunlight. 3) The deep pinkish red color of Saintpaulia ‘Delaware’flower was obtained first under an optical fiber lighting and a fluorescent light, a sun light in that order. 4) Regarding interred activity, photosynthetic rate and transpiration rate, intercellular CO, water absorption rate showed a similar tendency generally in spite of a little difference. Namely, transpiration rate and intercellular CO, $CO_2$ a absorption rate increased according to increase of photosynthetic rate. 5) Photosynthetic rate of test plants except Anthurium scherzerianum increased according to increase of light intensity and increased highest under optical fiber lighting in the same light intensity condition. Increases differed under fluorescent light and sun light. That of Saineaulia ‘Delaware’and Anthurium scherzerianum increased in the order of optical fiber, fluorescent light and sun light, but that of Kalanchoe blossfeldiana and Ardisia pusilla increased in the order of optical fiber lighting, sun light and fluorescent light. Summing up these results, In visual value or internal health status of all experimental plants we obtained the highest result under an optical fiber lighting. Finally, we need to introduce an optical fiber lighting in interior landscape space as main light source.

• 대한전자공학회논문지
• /
• 제25권5호
• /
• pp.495-500
• /
• 1988

The effectiveness of tri layer resist (TLR) technique is compared with that of single layer resist (SLR) technique in order to make a 0.8um pattern with the linewidth deviation of 10 percents. SLR technique is not appropriate to shape the micro-pattern on oxide and aluminum steps because of the standing wave effect and the light scattering effect in shaping the resist pattern. On the contrary, the uniform line with a width of 0.8um on oxide and aluminum steps can be formed by TLR technique, reducting such effects. The planarization and the light absorption coefficient of the bottom layer resist in TLR are optimized by exposing it to ultra violet light after baking it for 30min at 230\ulcorner. An uniform line with a width of 0.8um on oxide step is defined with the light absorption coefficient of 0.85 whereas that on aluminum step is defined with 0.95.

• Journal of the Optical Society of Korea
• /
• 제7권3호
• /
• pp.174-179
• /
• 2003

We construct a four-level system where a metastable state is included in an $Er^{3＋}$ Doped Yttrium aluminum garnet (YAG) crystal. Because of the action of the coherent field, the traditional light amplification with inversion can be exhibited with remarkable variation. As a result, we propose a method to achieve the gain equalization by atomic coherence. At the same time, we find that the high index of refraction accompanied by vanishing absorption can also be reached in this model. We also find that a higher index of refraction with zero absorption can be easily obtained when the coherent field is off resonance.

• 원예과학기술지
• /
• 제34권1호
• /
• pp.84-93
• /
• 2016

인공광 식물공장은 조명에 많은 전력이 소요되므로 광이용효율의 향상은 필수적이다. 본 연구에서는 식물공장의 LED 광원에 산란 유리를 사용함으로써 광이용효율을 향상하고자 하였다. 실험에는 Haze factor 40%와 80%의 산란 유리가 적용된 두 가지 처리구와 산란 유리를 사용하지 않은 대조구를 두었다. 3-D 광선추적기법을 이용하여 상추 작물의 군락 광분포를 분석하였으며 군락 광합성률은 밀폐 아크릴 챔버를 이용하여 측정하였다. 각 처리구 별로 16주의 상추를 수경재배 방식으로 28일간 재배하여 생장량을 비교하였다. 시뮬레이션 결과, 모든 처리구에서 작물의 상단부에 광량이 집중되었고 대조구에서 작물 상부에 광량 핫스팟이 발생하며 처리구에 비하여 광이용효율이 감소하였다. 총 광 흡수량은 대조구에서 가장 높았으나 유효 광 흡수량은 처리구에서 더 높았고 산란광의 비율이 높은 처리에서 더 높게 나타났다. 작물의 군락 광합성률과 생장량은 산란 유리를 사용한 처리구에서 대조구에 비해 높게 나타났다. 결과적으로 산란 유리의 이용을 통해 상추의 군락 내 광분포가 개선되었고 군락 광합성률 및 생장량이 증가하여 식물공장의 광이용효율이 향상되는 것으로 나타났다.

• Biotechnology and Bioprocess Engineering:BBE
• /
• 제4권1호
• /
• pp.78-81
• /
• 1999

Light penetration depth in high-density Chlorella cultures can be successfully estimated by Beer-Lambert's law. The efficiency of light energy absorption algal cultures was so high that algal cells near the illuminating surface shade the cells deep in the culture. To exploit the potential of high-density algal cultures, this mutual shading should be eliminated or minimized. However, providing more light energy will not ease the situation and it will simply drop the overall light utilization efficiency.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
• /
• pp.226-226
• /
• 2013

Si is a dominant solar material, which is the second most abundant element in the earth giving a benefit in the aspect in cost with low toxicity. However, the inherent limit of Si has an indirect band gap of 1.1 eV resulting in the limited optical absorption. Therefore, a critical issue has been raised to increase the utilization of the incident light into the Si absorber. The enhancement of light absorption is a crucial to improve the performances and thus relieves the cost burden of Si photovoltaics. For the optical aspect, an efficient design of a front surface, where the incident light comes in, has been intensively investigated to improve the performance of photon absorption. Lambertian light trapping can be attained when the light active surface is ideally rough to increase the optical length by about 50 compared to a planar substrate. This suggests that an efficient design may reduce thickness of the Si absorber from the conventional 100~300 ${\mu}m$ to less than 3 ${\mu}m$. Theoretically, a hole-array structure satisfies an equivalent efficiency of c-Si with only one-twelfth mass and one-sixth thickness. Various approaches have been applied to improve the incident light utilization in a Si absorber using textured structures, periodic gratings, photonic crystals, and nanorod arrays. We have designed hole and pillar structured Si absorbers. Four-different Si absorbers have been simultaneously fabricated on an identical Si wafer with hole arrays or pillar arrays at a fixed depth of 2 ${\mu}m$. We have found that the significant enhanced solar cell performances both for the hole arrayed and pillar arrayed Si absorbers compared to that of a planar Si wafer resulting from the effective improvement in the quantum efficiencies.

• 전기학회논문지
• /
• 제60권6호
• /
• pp.1169-1174
• /
• 2011

CdTe thin-film solar cell technology is well known that it can theoretically improve its conversion efficiency and manufacturing costs compared to the conventional silicon solar cell technology, due to its optical band gap energy (about 1.45eV) for solar energy absorption, high light absorption capability and low cost requirements for producing solar cells. Although the prior studies obtained the high light absorption, CdTe thin film solar cell has not been come up to the sufficient efficiency yet. So, doping method was selected for the improvement of the electrical characteristics in CdTe solar cells. Some elements including Cu, Ag, Cd and Te were generally used for the p-dopant as substitutional acceptors in CdTe thin film. In this study, the sputtering-deposited CdTe thin film was immersed in $AgNO_3$ solution for ion exchange method to dope Ag ions. The effects of immersion temperature and Ag-concentration were investigated on the optical properties and electrical characteristics of CdTe thin film by using Auger electron spectroscopy depth-profile, UV-visible spectrophotometer, and a Hall effect measurement system. The best optical and electrical characteristics were sucessfully obtained by Ag doping at high temperature and concentration. The larger and more uniform diffusion of Ag ions made increase of the Ag ion density in CdTe thin film to decrease the series resistance as well as mede the faster diffusion of light by the metal ions to enhance the light absorption.