• Title/Summary/Keyword: 광변색

Search Result 102, Processing Time 0.03 seconds

Studies on Discoloration of 16 Commercial wood Grown in Korea (한국산(韓國産) 유용목재(有用木材)의 변색(變色)에 관한 연구)

  • Kim, Moom-Kyu;Chung, Dae-Kyo
    • Journal of the Korean Wood Science and Technology
    • /
    • v.14 no.4
    • /
    • pp.40-46
    • /
    • 1986
  • Change of color of woods is a trouble frequently found in decorative wood products. In this paper, studies were carried out on discoloation sensitivities of wood specimens to iron (0.1%, $FeCl_3{\cdot}6H_2O$), alkali (pH12.0, NaOH), acid (pH 1.0 $C_2H_2O_4$) and exposing to sunlight (40 hrs.). Four soft-woods and eleven hard-woods grown in Korea were used in this test. The results obtained were as follows: 1. In iron stain, strong discolored wood species were Larix leptolepis, Quercus mongolica. Zelkova serrata and Prunus yedoensis, and light discolored were Paulownia lomentosa and Pinus rigida. 2. In alkali stain. light discolored wood species were Abies holophylla, Kalopanax pictum, Populus ${\times}$ albaglandulosa, Acer mono, Pinus rigida, Pinus densiflora, Quercus mongolica, Betula platyphylla var. japonica, Prunus yedoensis, Zelkova serrata, Populus euramericana, Pinus koraiensis and Paulownia tomentosa, but there was no wood species of strong discolored compared with the color difference values of other reports. 3. In acid stain, light discolored wood species were Pinus rigida, Paulownia tomentosa. Pinus koraiensis, Quercus mongolica, Kalopanax piclum and Acer mone, but there was no strong discolored species compared with the color difference values of other reports. 4. In exposing to sunlight, strong discolored species were Larix leptolepis, Acer mono, Paulownia tomentosa, Populus euramericana, Pinus densijlora, Robinia pseudoacacia, Abies holophylla, Populus ${\times}$ albaglandulosa, Zelkova serrata, Prunus yedoensis and Pinus rigida, and light discolored was Alnus japonica. In general, it was shown that Korean wood species were susceptible to change of color by exposing to sunlight and iron stain compared with by alkali stain and acid stain.

  • PDF

Tantalum Oxide를 활용한 스마트 윈도우용 전기변색 디바이스 특성

  • Park, Jae-Seong;Seo, Chang-Taek;Lee, Dong-Ik;Sin, Han-Jae;Hwang, Do-Yeon;Lee, Jeong-Hwan;Park, Seong-Eun
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2013.02a
    • /
    • pp.496-496
    • /
    • 2013
  • 스마트윈도우는 디스플레이, 산업용 외장재 등 다양한 분야에 응용이 가능하며, 특히 전기변색을 이용한 디바이스는 나노코팅 기술을 통한 나노입자 및 나노가공제어 등 나노융합기술을 접목할 수 있다. 전기변색 디바이스는유리 또는 필름 기판소재를 통해 제작이 가능하며, 본 연구에서는 전기변색의 산화, 환원반응에 의해 재료의 광특성이 가역적으로 변화할 수 있는 물질을 증착하여 기존 라미네이터 및 Sol-Gel방식의 전해질보다 열화현상에의한 성능저하를 막아주는 박막전해질 코팅 연구이다. 전기변색 소자는 외부 인가 전압(external voltage)에 의해 유도된 전하의 주입(injection) 과 추출(extraction)을 통하여 그 광학적 특성(optical property)을 가역적으로(reversibly) 변 화시킬 수 있는 특징을 가지고 있다. 전기변색소재의 원리를 간략하게 설명하면 대표적인 환원착색 물질인 전기변색층(WO, MoO, Nb2O5 등)으로 Li+ 또는 H+과 전자가 주입되면 전기변색되고 방출 시는 투명하게 되며, 반대로산화착색 물질인(V2O5, NiO, IrO, MnO 등)으로 Li+ 또는 H+과 전자가 방출되면 변색되고 주입되면 투명하게 되는 것이다. 본 연구에서는 전자가 주입되는 환원착색물질인 WO와 함께 Ta2O5박막을 증착하여 광학적특성을 연구하고 박막의 두께 및 전압인가에따른 변색 및 응답속도를 연구하고자 한다.

  • PDF

Protections of the Green Colors from Gardenia jasminoides with Polyoxyethylene Dimethicone (Polyoxyethylene Dimethicone을 이용한 천연색소 치자그린의 변색방지)

  • Lee, Dong-Ryul;Kang, Tae-Jun;Kim, Ki-Sun;Lee, Cheon-Koo
    • Journal of the Society of Cosmetic Scientists of Korea
    • /
    • v.32 no.2 s.57
    • /
    • pp.89-91
    • /
    • 2006
  • The objectives of this study were to find for suitable chemical reagents to use as a green-color protector for Gardenia jasminoldes Green pigment and to compare the effectiveness of these reagents for discoloration prevention. Gardenia jasminoldes Green treated with polyoxyethylene (POE) (12) dimethicone shouted a greener color than those treated with methoxycinnamidopropyl hydroxysultaine ultraviolet stabilizers after ultraviolet radiation (UVR). The experimental results exhibited that the concentration of the POE (12) dimethicone affected the effectiveness of green-color conservation. The greenest rotor was obtained by treating 0.10 wt% aquous solution of Gardenia jasminoldes Green with 1.0 wt% POE (12) dimethicone aqueous solution and the absorbances of the solutions after UVR were increased from 78% to 95% in comparison with the untreated. In addition, the Gardenia jasminoldes Green aqueous solution mixed with POE (12) dimethicone showed great green-color fastness in outdoor weathering exposure. The mechanism of the green color protection under UVR is unclear, however the dimethicone group of POE (12) dimethicone may play and important role in the stabilization.

Relationship between Discoloration and Flower Pigment after Pressing in Yellow-Colored Flowers (황색 꽃의 압화 후 변색과 화색소와의 관련성)

  • Byun, Mi Soon;Cho, Eun Jeong;Kim, Kiu Weon
    • FLOWER RESEARCH JOURNAL
    • /
    • v.16 no.1
    • /
    • pp.76-84
    • /
    • 2008
  • This study was conducted to find out the cause of discoloration after pressing yellow-colored flowers. Plant materials used were Lilium Asiatic Hybrids, Oncidium spp., Rosa hybrida, $Tulipa{\times}gesneriana$, Antirrhinum majus, Dianthus caryophyllus, Freesia hybrida, Zantedeschia elliottiana, Gerbera jamesonii, Helianthus annuus, and Ranunculus asiaticus. Thickness, ratio of length to width, and water content of petals did not considerably affect discoloration of pressed flowers. Expression of yellow color in petals was caused by carotenoids in Lilium Asiatic Hybrids, Oncidium spp., Rosa hybrida and $Tulipa{\times}gesneriana$, by flavonoids in Antirrhinum majus, Dianthus caryophyllus, Freesia hybrida and Zantedeschia elliottiana, and by coexistence of carotenoids and flavonoids in Gerbera jamesonii, Helianthus annuus and Ranunculus asiaticus. Carotenoids that expressed yellow color in petals affected significantly on discoloration in pressed flowers containing carotenoids alone or both carotenoids and flavonoids. However, discoloration was hardly ever found in yellow-colored species as affected by flavonoids. Dark treatment was effective for almost perfect preservation in color of pressed flowers, while light treatment resulted in severe discoloration.

Improvement of Bleaching Performance of Photosensitive Electrochromic Device by the Additive of TEMPOL (TEMPOL 첨가제 적용에 의한 광감응형 전기변색 소자 탈색성능 향상)

  • Song, Seung Han;Park, Hee sung;Cho, Churl Hee;Hong, Sungjun;Han, Chi-Hwan
    • Journal of the Korean Chemical Society
    • /
    • v.66 no.3
    • /
    • pp.209-217
    • /
    • 2022
  • We have developed photosensitive electrochromic smart windows that does not require any transparent conducting oxide (TCO) substrate. In our previous study, we demonstrated that a flexible film-type device made with a low temperature curing WO3 sol and TiO2 sol could show a reversible and rapid switching between colored and bleached state via incorporation of platinum catalysts on the surface of WO3 layer. However, when these devices were exposed to sunlight over 4 hour, it was confirmed that they did not return to fully bleached state in the darkened state due to their overcoloring process. In this study, we added 4-hydroxy-(2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPOL) as an additive to the electrolyte of photosensitive electrochromic device to effectively prevent the undesired overcoloring process. The resulting device with TEMPOL indeed did not undergo excessive coloration and showed great reversibility even after being exposed to sunlight for over 4 hours. Various concentrations of TEMPOL were applied to compare changes in the visible transmittance and coloring/bleaching kinetics of devices. In terms of energetic point of view, we proposed a plausible mechanism of TEMPOL to prevent excessive coloration.

Control of the Photo-induced Discoloration of the Handmade Korean Paper with Polyethylene Glycol (Polyethylene Glycol에 의한 수록한지(手漉韓紙)의 광(光) 변색(變色) 억제(抑制))

  • Cheon, Cheol;Park, Soo-Ahn
    • Journal of Korean Society of Forest Science
    • /
    • v.89 no.2
    • /
    • pp.161-166
    • /
    • 2000
  • Classified handmade Korean paper which has been commonly used as the material for the paper cultural assets divide into four classes. We irradiated xenon arc lamp, which has almost the same spectrum distribution as natural sunlight, to test photo-induced of discoloration according to PEG molecular weight and concentration. So, we reach the followings. 1) Unbleached handmade Korean paper with PEG showed rapid decrease of brightness for 10 hours after photo-irradiation, regardless of molecular weight of PEG, but, after 10 hours, it showed gradual increase of brightness. From this, it proved that there was an effect of preventing discoloration of photo-irradiation. 2) Chemical bleached handmade Korean paper showed increase of brightness after 20 hours. Though time was delayed in increase of brightness, there was also an effect of preventing discoloration of photo-irradiation in chemical bleached paper. 3) Handmade Korean paper made with abet-mosk showed the lowest of brightness when it was tested on 400-20% PEG. Before photo-irradiation, the brightness of paper, applied it, was the lowest, but it showed the least difference of brightness after photo-irradiation. From this, it proved that there was the greatest effect of preventing discoloration in this paper. 4) Preventing yellowish, the first phenomena by photo-irradiation ageing with applying PEG was proved that there was the decrease of value of $b^*$ +, and increase value of $L^*$, which could fairly prevent decrease of brightness.

  • PDF

Synthesis of the photochromic and electrochromic dyes and their sensible properties (I) - Dyeing application with photochromic moiety to the fiber substrate- (광변색성 및 전기변색성 색소의 합성 및 특성(I) -광변색성 특성의 섬유소재에의 응용-)

  • Son Young-A;Park Young-Min;Kim Byung-Soon;Kim Sung-Hoon
    • Textile Coloration and Finishing
    • /
    • v.18 no.2 s.87
    • /
    • pp.24-30
    • /
    • 2006
  • The photosensitive spiroxazine compound and the electrosensitive viologen compound were prepared to examine their practical application feasibilities and behaviors. These dyes represent corresponding chromism effects related to their own characteristics of the dye molecules. Thus, the prepared dyes were characterized and their absorption spectra were also investigated. Besides, an interest on direct spiroxazine exhaustion to the polyamide substrates and its photochromic effects within the fiber molecules were determined. The photochromic reaction on the substrates was clearly observed and its reversible decoloration behaviors responded.

Study on the photo-induced refractive index change of diarylethene derivative using fiber-to-planar waveguide coupler (광섬유-평면도파로 결합기를 이용한 광변색성 디아릴에텐 유도체의 광유도 굴절률 변화에 관한 연구)

  • 조강민;윤정현;임선정;박수영;강신원
    • Korean Journal of Optics and Photonics
    • /
    • v.15 no.2
    • /
    • pp.109-113
    • /
    • 2004
  • We have manufactured and characterized the fiber-to-Planar Waveguide Coupler for analysis of the photo-induced refractive index change of DM-BTE .(l,2-bis[2,5-dimethylthio-phen-3-yl]-hexafluorocyclopentene) When irradiated with ultraviolet light, the colorless diarylethene(DM-BTE)-crystal turned red while keeping the crystal shape. The red color was bleached by irradiation with visible light(λ>450 nm). The resonant wavelength was shifted and recovered owing to the refractive index variation of the planar waveguide because of its photo-functional properties on exposure to UV and visible light. The wavelength responses of this switch by UV exposure were measured as 0.057 nm/sec with saturation time of 60 seconds. and when illuminated by visible light, resonance wavelength variations were measured as 0.028 nm/sec, with recovery time of 140 seconds.