• Applied Chemistry for Engineering
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• v.28 no.2
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• pp.245-251
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• 2017

In this study, ZnO, which is widely known as a non $TiO_2$ photocatalyst, was synthesized using coprecipitation method and Ag was added in order to improve the catalytic performance. The physicochemical characteristics of the synthesized ZnO and Ag/ZnO particles were checked using X-ray diffraction (XRD), UV-visible spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), photoluminescence (PL), and photocurrent measurements. The performance of catalysts was tested by $H_2$ production using the photolysis of $H_2O$ with MeOH. By adding Ag which plays a role as an electron capture on the ZnO catalyst, the performance increased due to the recombination of excited electrons and holes. In particular, $8.60{\mu}mol\;g^{-1}$ $H_2$ was produced after 10 h reaction over the 0.50 mol% Ag/ZnO.

• Polymer(Korea)
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• v.29 no.4
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• pp.413-417
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• 2005

Orientations of liquid crystal molecules on a surface of a film of photoreactive polyvinylcinnamate were investigated in order to apply as an alignment layer of LCD. When the polyvinylcinnamate film was exposed to linearly polarized W light, optical anisotropy was induced in the film through a selective photoreaction. Liquid crystal molecules on a surface of the film was aligned along the oriented polymer chain direction through intermolecular interactions. Thermal and light stability of the photoaligned LC cell were studied by investigating LC alignment changes after the alignment layer was treated with heat and W light. When the film was exposed with linearly polarized UV several times, the LC alignment was induced only along the final UV exposure direction.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.24 no.4
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• pp.144-149
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• 1988

The purpose of this study is to find the light intensity which induced maximum gathering rate and to observe the variation of the gathering rate both in daytime and tat night by using Striped puffer, Fugu xanthopterus (Temminck et Schlegel). An experimental tank(360L$\times$50W$\times$55H cm) was set up in a dark room. An illumination system was attached to the end of one side of the tank to control horizontal light intensity. Eight artificial light sources were prepared by combination of three light bulbs (10W, 60W, 100W) and eight filters. During the experiment water depth was maintained 50 cm level in the tank. The tank was marked into six longitudinal sections each being 60cm long to observe the distribution of fish. The fish were acclimatized in dark condition for 50 minutes prior to the main experiment. Upon turning on the light, the number of fish in each section was counted 60 times every 30 seconds, and the gathering rate was obtained from the average number of fish in each section. The light intensity inducing maximum gathering rate was 298.56 lux (188.44-444.96 lux) at daytime and 298.56 lux (188.44-444.96 lux) at night. The variation of the gathering rate of fish in illumination time was increasing trend fluctuately and did not show any distinctive difference between day and night.

• Polymer(Korea)
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• v.28 no.6
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• pp.494-501
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• 2004

A new alkali developable photosensitive poly(amic acid) (PAA-0) with transmittance at 400 nm was synthesized from cyclobutane-1,2,3,4-tetracarboxylic dianhydride, 2-(methacryloyloxy)ethyl-3,5-diamino-benzoate and 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyl disiloxane in N-methyl-2-pyrrolidinone. Photosensitivity of the PAA-0 was investigated at 365-400 nm in the presence of a photoinitiator using a high pressure mercury lamp. The photo-cured poly(amic acid) was insoluble toward aqueous 2.38 wt% tetramethylammonium hydroxide solution. Negative pattern of the PAA-0 with 25 ${\mu}{\textrm}{m}$ resolution was obtained by developing with 2.38 wt% tetramethylammonium hydroxide solution after exposure of 600 mJ/$\textrm{cm}^2$ in the presence of 2,2-dimethoxy-2-phenyl-acetophenone as a photoinitiator. The patterned poly(amic acid) was converted to polyimide by thermal curing at 25$0^{\circ}C$ for 50 min, which showed chemical resistance against photoresist stripper as well as good transmittance at 400 nm.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10b
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• pp.649-651
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• 2004

본 논문은 전역조명을 효율적으로 계산하기 위한 렌더링 방법인 photon mapping 에서 물체의 조명 값을 계산하는데 필요한 radiance를 구하는 새로운 방법을 제안한다. 기존의 방법은 포톤과 표면과의 반응 종류에 상관없이 포톤을 저장할 때 단지 위치와 기타 정보만을 저장하는 방법을 사용했었다. 본 논문에서는 각각의 포톤에 하나의 반지름을 부여하여 물체 표면과의 반응 종류에 따라 가변적으로 반지름을 조절하는 방법을 사용하였다. 구현 후 실험 결과 비슷한 렌러링 시간에 이전에 사용되던 방법에 비해서 caustic 과 그림자 표현에서 더 나은 이미지 품질을 보여주었다. 또한 이전 방법에서 caustic을 명확하게 표현하기 위해서 사용했던 caustic map을 사용한 경우에 비해서 더 빠르게 렌더링 되는 결과가 나타났다.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 1999.10a
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• pp.57-58
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• 1999

과거의 대기오염은 $SO_2$와 같은 1차 오염물질이 문제가 되었다. 그러나 저황 연료유의 사용 의무화로 인해 점차 줄어드는 추세에 있는 반면, 최근에는 급속한 산업화와 소득의 증대로 기하급수적으로 늘어나는 자동차와 산업시설에서 배출되는 질소산화물($NO_x$)과 탄화수소류(HCs) 그리고 휘발성 유기화합물 (VOCs)을 포함하는 다양한 천연, 인공물질이 태양광과 반응(광화학반응)하여 2차적으로 생성된 $O_3$ 등에 의한 대기오염이 심각해지고 있다. (전병일 등, 1995)(중략)

• Proceedings of the Korean Fiber Society Conference
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• 1998.10a
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• pp.118-121
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• 1998

양모는 풍후와 광에 의해 모단(tip)의 소수성 부분이 많이 상해되는 반면 모근(root)은 상대적으로 안정하다. 이로 인하여 모단에 비하여 모근에서 염료의 확산이 더 빠르기 때문에, 양모염색에 있어서 tipping현상이 나타나게 된다. 반응성염료로 양모를 염색하는 경우 전형적인 tippy-dyeing이 일어난다. 일반적으로 이들은 두 개 이상의 수용성기를 가지므로 친수성이 강하여, 모근보다 모단에 더 많이 흡진된다. (중략)

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.11a
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• pp.382-383
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• 2000

산업이 발달함에 따라 휘발성 유기 화합물(VOC : Volatile Organic Compound)의 배출이 급증하고 있다. 이러한 VOC들은 대기중에서 산화물과 공존시 태양광의 작용을 받아 광화학반응을 일으켜 오존등의 광화학 산화성 물질을 생성시켜 광화학 스모그를 유발시키고 일부 VOC는 그 자체로서도 암을 유발시키는등 인체에 좋지 않은 영향을 미치게 된다. 이러한 VOC중 상당수는 대기중에 미량만 존재하게 되더라도 악취를 유발시켜 불쾌감을 주게된다. (중략)

• Korean Journal of Plant Resources
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• v.12 no.2
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• pp.139-144
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• 1999

The present study was carried out to determine the effects of lighting directions and light intensities on the growth of in vitro plantlets of strawberry, potato and lily. The growth of plantlets was affected by two different lighting systems, downward and sideward lighting system. There were no difference for the plantlets of strawberry regardless of lighting directions. However, leaf area, fresh weight and dry weight have increased as the light intensity increased. Also, plant height and root length on node culture of potato decreased at high intensity of the sideward lighting, while thickness of stem and root was thicker, fresh weight and dry weight were heavier, and leaf area was increased. Also, bulblet formation on scale culture of lily has been abundant, and fresh weight and dry weight were increased. Thus, the sideward lighting system which loaded three stories for culture vessels with raising light intensity into culture vessels instead of conventional downward lighting system promoted growth and raised the efficiency of production of high quality microplant.

• Korean Journal of Agricultural and Forest Meteorology
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• v.13 no.3
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• pp.115-122
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• 2011

The impacts of elevated temperature and $CO_2$ were studied on the seedlings of Maackia amurensis and Viburnum opulus var. calvescens. The seedlings were grown in controlled-environment growth chambers with four combinations of temperature and $CO_2$ treatments: $25^{\circ}C$ + ambient $CO_2$ (400 ppm), $25^{\circ}C$ + elevated $CO_2$ (800 ppm), $30^{\circ}C$ + ambient $CO_2$ (400 ppm), and $30^{\circ}C$ + elevated $CO_2$ (800 ppm). Under elevated temperature and $CO_2$ concentration, the dry weight decreased in seedlings of M. amurensis, but increased in seedlings of V. opulus var. calvescens. In addition, the shoot to root (S/R) ratio in M. amurensis reduced but that of V. opulus var. calvescens increased under elevated $CO_2$ concentration. The S/R ratios of two tree species increased under higher temperature. M. amurensis represented lower carboxylation efficiency under higher temperature and $CO_2$ concentration and that of V. opulus var. calvescens showed lower values under the only higher temperature. Photosynthetic pigment content of in the leaves of M. amurensis was lower under higher $CO_2$ concentration and higher under the increase of temperature, but that of V. V. opulus var. calvescens decreased according to the increase of temperature. Chlorophyll a/b ratios of M. amurensis and V. V. opulus var. calvescens decreased obviously with the increase of $CO_2$ concentration and temperature, respectively. In conclusion, the growth and physiological responses under the environmental changes such as temperature and $CO_2$ concentration depend on the tree species. Therefore, more studies are needed to predict the response of each tree species against the climate changes.