• Elastomers and Composites
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• 제50권1호
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• pp.1-6
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• 2015

Polybutadiene rubber (BR) has been well known that its physical and chemical properties are changed when it is exposed to ultraviolet light undergoing photooxidation. In this study, photooxdiation process of BR vulcanizate was investigated using a high pressure mercury lamp used as an outdoor lighting, which has high UV radiation efficiency and reasonable cost. Discoloration and crack formation of photooxdized BR vulcanite surface were examined using an image analyzer. Change of chemical functional groups of BR vulcanite surface by photooxidation was investigated using ATR-FTIR, and variation of the crosslink density with the UV irradiation time was investigated. By increasing the UV irradiation time, the crosslink density steeply increased after a period of time and did not increase any more. Formation of hydroxyl (~OH) and carbonyl (~C=O) groups on the BR vulcanizate surface increased and the1,4-cis unit was converted to the 1,4-trans unit as the photooxidation was proceeded.

• Macromolecular Research
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• 제9권5호
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• pp.253-258
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• 2001

Crosslinked poly(ethylene glycol)s (PEGs) were prepared by ultraviolet irradiation of low molar mass, liquid PEGs in the presence of benzophenone (BP) as a photoinitiator. The networks obtained have been characterized by DSC, IR, and contact angle measurements, and their water absorption and equilibrium swelling have been examined. The percent of gel formed and degree of swelling of the networks in water were dependent on the amount of BP in the reaction mixture, irradiation time and molar mass of PEG. Gel fraction yield exceeded 84%, and equilibrium swelling in water varied from 49 to 244%.

• 한국응용과학기술학회지
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• 제14권2호
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• pp.35-40
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• 1997

The organization of phospholipid monolayers and their monolayers mixed with fatty acid containing azobenzene on the water surface was investigated by means of the displacement current measurement method. The phase transition from the gaseous phase to the gaseous-fluid phase which accompanies the polar ordering of phospholipid molecules was detected in the range of immeasurably low surface pressure. The molecular area which gives the onset of the transition was determined for phospholipid monolayers. The Maxwell displacement current(MDC) pulses were generated across mixed monolayers due to the photoisomerization of fatty acid containing azobenzene by alternating irradiation of ultraviolet and visible light, because the condensation of pure azobenzene monolayers was loosened by the introduction of phospholipids into the monolayers. The displacement currents generated during light irradiation were also investgated in connection with monolayer compression cycles. It was found that the maximum of MDC appeared at the molecular area just before the initial rise of surface pressure in compression cycles.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 춘계학술대회 논문집
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• pp.267-270
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• 1998

In this study, we investigated the generation of pretilt angle for nematic liquid crystal (NLC) in a cell with oblique non-polarized ultraviolet (UV) light irradiation on polyimide (PI) surfaces. It was found that the monodomain alignment of the NLC is obtained in a cell with an angle of incidence of 70∼85$^{\circ}$on PI surface. We consider that the monodomain alignment of NLC is attributed to anisotropic dispersion force effect due to Photo-depolymerization of polymer on PI surfaces. Also, pretilt angle of NLC is generated about 3$^{\circ}$ with an angle of incidence of 70∼75$^{\circ}$. It is considered that the pretilt angle generation in NLC is attributed to interaction between the LC molecules and the polymer surfaces.

• 한국전기전자재료학회논문지
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• 제11권10호
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• pp.911-917
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• 1998

In this paper, we have investigated the generation of pretilt angle for nematic liquid crystal (NLC) in a cell with oblique non-polarized ultraviolet(UV) light irradiation polyimide (PI) surface. It was found that the monodomain alignment of the NLC is obtained with an angle of incidence of 70∼85。 on PI surface. It is considered that the monodomain alignment of NLC is attributed to anisotropic of NLC is about 3。 with and angle of incidence of 70∼75。. Finally, we observed that the voltage-transmittance, response time, and voltage-holding-ratio(VHR) characteristics of photo-aligned twisted nematic(TN)-LCD with and angle of incidence of 85。 on PI surface were almost same compared to rubbing -treated TN-LCD.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1255-1260
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• 2004

Decomposition of ozone at room temperature was investigated comparatively with commercial monolithic ozone decomposition catalyst (ODC, $MnO_2$) and monolithic photo catalyst ($TiO_2$). The effects of residence time, UV (ultraviolet) light dependence and ozone concentration on the conversion was presented. UV ray was irradiated using BLB (black light blue) lamp ($315{\sim}400$ nm), supplied with a constant intensity in the reactor. The concentration of ozone in the square-shape reactor can be controlled by combining the DBD (dielectric barrier discharge) reactor with an AC high voltage supply system. The catalytic performance, in presence of UV irradiation did not show significant changes for $MnO_2$ catalyst. $TiO_2$ catalyst was the different case, which showed higher decomposition activity in presence of UV irradiation. Deactivation of catalyst detected by real-time ozone monitor for 120 hours with a constant inlet ozone concentration.

• 한국동물학회지
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• 제25권3호
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• pp.107-114
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• 1982

수정 직후 일어나는 배, 복측 결정의 기작을 알아 보기 위하여 자외선의 조사와 난의 회전방법을 한국산 무미양서류에 적용하였다. 제 1 분열전의 수정난을 일정기간 $90^\\cdot$회전시키면 자외선에 의한 전형적인 발생결함을 억제시킬수 있었다. 한편, 제 1 분열 전 단기간 회전시킨 난으로부터 발생한 embryo의 원구배순부의 위치도 회전시 중력의 반대 방향에 위치하였던 새로운 장소에 형성되었다. 위의 결과는 다른 무미, 유미양서류를 통하여 얻은 지식과 비교 검토하여 초기발생 기작을 이해하는데 접근하고자 하였다.

• Journal of Plant Biology
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• 제5권3호
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• pp.30-36
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• 1962

The mechanism of synthesis of the toacco mosaic virus(TMV) and the potato virus X(PVX) was investigated using the methods of ultraviolet light irradiation and serological analysis. In vitro irradiation of UV on the infected tobacco juice for 10 minutes caused the infectivity of TMV and PVX to decrease markedly on their respective local lesion indicator hosts, Nicotiana glutinosa L. and Gomphrena globosa L., indicating that UV destroys directly the infectivity of the virus particles. Ten minutes after the UV was irradiated on the leaves of the two indicator hosts before inoculation, the infectivity of TMV decreased as it was irradiated in vitro, whereas that of PVX increased by 26% as compared with the unirradiated control. When the two viruses were mix-inoculated in the common host of tobacco and the synthetic products were analyzed by serological methods for a two week infection period, it was found that both viruses were multiplying more rapidly and abundantly than they were singly inoculated into the same host species. Titers from mixed series were often two times as high as those of singly inoculated series. A mechanism of competition in the synthesis between the mixed viruses in the common host is postulated.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.283-286
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• 2000

In this paper, generation form of displacement current was compared and measured induce monolayers which 8A5H with Pure azobenzene. Light response of two monolayers which compared and measured though they are the same isomer. The experimental results are as following; In case of ultraviolet($\lambda_1$) and visible($\lambda_2$) irradiation on 8A5H induce monolayers depositioned on board the peak of current was detected about 10[fA]. but light irradiation on pure azobenzene any particular reaction for detailed. This is the reason of hydrophobicity construct in molecule structures its molecule dynamic behaviour in cis and trans was not due to activated.

• 한국전기전자재료학회논문지
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• 제21권9호
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• pp.859-862
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• 2008

We have realized static image on organic light emitting diodes (OLEDs) using photoluminescence degradation. Ultraviolet (UV) was irradiated to the glass side of device. UV power was 350 Wand the wavelength was 365 nm. The UV irradiation gives rise to the degradation of photoluminescence. Due to the degradation, the current density-voltage curve was shifted to the higher voltage side and the luminescence was also degraded by the current and photoluminescence drop. The negative imaged films were prepared to control the transmittance of UV. The UV light was passed through the film. By this method, the film image was transferred to the device with reversed image and the static image was realized on the OLED.