Ultraviolet spectroscopy of Pr+3 and its use in making ultraviolet filters

Muhammad Maqbool,Iftikhar Ahmad 한국물리학회 2009 Current Applied Physics Vol.9 No.1

Sputtered deposited thin films of AlN:Pr and GaN:Pr emit in ultraviolet–visible and visible regions of the spectrum, respectively, under electron excitation in cathodoluminescence apparatus. The goal is to study the ultraviolet emission from Pr+3 when doped in nitride semiconductor hosts. Luminescence peaks at a wavelength of 295 nm (4.2 eV), 335 nm (3.7 eV) and 385 nm (3.24 eV) are observed as a result from 1S0 → 1G4, 1S0 → 1D2 and 1S0 → 1I6 transitions, respectively. However the 1S0 → 1G4 and 1S0 → 1D2 transitions are not observed when Pr+3 is doped in GaN host. The bandgap of GaN absorbs the ultraviolet radiation emitted from Pr+3 and hence GaN can be used as ultraviolet filter for radiation shielding and protection purposes. AlN is transparent to ultraviolet due to its wide bandgap of 6.2 eV. Sputtered deposited thin films of AlN:Pr and GaN:Pr emit in ultraviolet–visible and visible regions of the spectrum, respectively, under electron excitation in cathodoluminescence apparatus. The goal is to study the ultraviolet emission from Pr+3 when doped in nitride semiconductor hosts. Luminescence peaks at a wavelength of 295 nm (4.2 eV), 335 nm (3.7 eV) and 385 nm (3.24 eV) are observed as a result from 1S0 → 1G4, 1S0 → 1D2 and 1S0 → 1I6 transitions, respectively. However the 1S0 → 1G4 and 1S0 → 1D2 transitions are not observed when Pr+3 is doped in GaN host. The bandgap of GaN absorbs the ultraviolet radiation emitted from Pr+3 and hence GaN can be used as ultraviolet filter for radiation shielding and protection purposes. AlN is transparent to ultraviolet due to its wide bandgap of 6.2 eV.

Modification of the optoelectronic properties of two-dimensional MoS₂ crystals by ultraviolet-ozone treatment

Yang, Hae In,Park, Seonyoung,Choi, Woong Elsevier BV * North-Holland 2018 Applied Surface Science Vol.443 No.-

<P><B>Abstract</B></P> <P>We report the modification of the optoelectronic properties of mechanically-exfoliated single layer MoS<SUB>2</SUB> by ultraviolet-ozone exposure. Photoluminescence emission of pristine MoS<SUB>2</SUB> monotonically decreased and eventually quenched as ultraviolet-ozone exposure time increased from 0 to 10 min. The reduction of photoluminescence emission accompanied reduction of Raman modes, suggesting structural degradation in ultraviolet-ozone exposed MoS<SUB>2</SUB>. Analysis with X-ray photoelectron spectroscopy revealed that the formation of SO and MoO bonding increases with ultraviolet-ozone exposure time. Measurement of electrical transport properties of MoS<SUB>2</SUB> in a bottom-gate thin-film transistor configuration suggested the presence of insulating MoO<SUB>3</SUB> after ultraviolet-ozone exposure. These results demonstrate that ultraviolet-ozone exposure can significantly influence the optoelectronic properties of single layer MoS<SUB>2</SUB>, providing important implications on the application of MoS<SUB>2</SUB> and other two-dimensional materials into optoelectronic devices.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Modification of the optoelectronic properties of MoS<SUB>2</SUB> by ultraviolet-ozone treatment. </LI> <LI> Reduced photoluminescence intensity with increasing ultraviolet-ozone treatment time. </LI> <LI> Reduced Raman modes suggest structural degradation after ultraviolet-ozone treatment. </LI> <LI> Surface analysis suggest the presence of MoO<SUB>3</SUB> after ultraviolet-ozone treatment. </LI> </UL> </P>

Ultraviolet resistance on weft knitted fabric coated by benzotriazoles

Tuan Anh Nguyen,Nhu Tram Nguyen Nu 한국의류학회 2024 Fashion and Textiles Vol.11 No.1

Ultraviolet resistance upon four different types of weft knitted fabrics including Lacoste, Single Jersey, Rib and Interlock were experimentally measured and evaluated by ultraviolet–visible spectroscopy under effects of gauge, specific weight, fiber composition and finishing agent as benzotriazole derivatives. The results showed that ultraviolet protection factor (UPF) of Interlock sample reached the highest value at 42.7. Simultaneously, the higher gauge of Single Jersey knitted fabrics was, the better its ultraviolet protection exhibited. Also, insertion of polyester fibers or spandex fibers into cotton knitted fabrics with a certain ratio strongly increased UPF values. Notably, all UPFs of coated fabrics with a given content of benzotriazole were significantly improved and almost coated samples could undergo several washing cycles and still retain their inherent breathability. This work demonstrated that cotton knitted fabrics coated with benzotriazoles were excellently enhanced ultraviolet protection. Especially, the UPF values on Interlock or Rib specimens as well as Single Jersey samples blended with polyester/spandex fibers were found to be higher than 15.

감압대기 및 불활성가스 분위기에서 적합한 정전기 제거장치의 개발

이동훈 ( Dong Hoon Lee ),정필훈 ( Phil Hoon Jeong ),이수환 ( Su Hwan Lee ),김상효 ( Sang Hyo Kim ) 한국안전학회(구 한국산업안전학회) 2016 한국안전학회지 Vol.31 No.3

In LCD Display or semiconductor manufacturing processes, the anti-static technology of glass substrates and wafers becomes one of the most difficult issues which influence the yield of the semiconductor manufacturing. In order to overcome the problems of wafer surface contamination various issues such as ionization in decompressed vacuum and inactive gas(i.e. N2 gas, Ar gas, etc.) environment should be considered. Soft X ray radiation is adequate in air and O2 gas at atmospheric pressure while UV radiation is effective in N2 gas Ar gas and at reduced pressure. At this point of view, the “vacuum ultraviolet ray ionization” is one of the most suitable methods for static elimination. The vacuum ultraviolet can be categorized according to a short wavelength whose value is from 100 ㎚ to 200 ㎚. this is also called as an Extreme Ultraviolet. Most of these vacuum ultraviolet is absorbed in various substances including the air in the atmosphere. It is absorbed substances become to transit or expose the electrons, then the ionization is initially activated. In this study, static eliminator based on the vacuum ultraviolet ray under the above mentioned environment was tested and the results show how the ionization performance based on vacuum ultraviolet ray can be optimized. These vacuum ultraviolet ray performs better in extreme atmosphere than an ordinary atmospheric environment. Neutralization capability, therefore, shows its maximum value at 10-1~10-3 Torr pressure level, and than starts degrading as pressure is gradually reduced. Neutralization capability at this peak point is higher than that at reduced pressure about 104 times on the atmospheric pressure and by about 103 times on the inactive gas. The introductions of these technology make it possible to perfectly overcome problems caused by static electricity and to manufacture ULSI devices and LCD with high reliability.

골퍼들의 자외선차단제 인식과 정규라운딩 후 피부보습연구

하지성,장옥선,박안나 한국뷰티경영학회 2017 한국뷰티경영학회지 Vol.5 No.2

The purpose of this study is to research about the cognition of ultraviolet rays and the skin care against 95 golfers who visited golf course. 16 golfers were selected as test subjects to research the amount of moisture on facial skin after golf. 77.7% of test subjects understood that ultraviolet rays are harmful and they realized that the ultraviolet rays can cause pigmented skin lesion. However, 9.6% of people did not know it. Furthermore, 20.2% of people was not realized that sunburn can be caused by ultraviolet. According to this statement, people have low cognition of the harmfulness of the ultraviolet rays. Also 41.5% of test subjects answered that they don't have knowledge about sun protection factor, SPF and PA. 79.6% of golfers use sunscreen before they start to play golf. However, 20.5% of people do not use sunscreen not at all, or they don't use it when ultraviolet rays are not strong. 71.4% of test subjects do not use sunscreen because it is inconvenient. 26.9% of test subjects think that maker or brand is an important factor to choose sunscreen. 67.4% of people use sunscreen right before starting the golf but 60.9% of them do not use sunscreen over and over during golf. After the game, 28% of test subjects use mask pack for self skin care, and 37.6% of people use basic skin care product. There was an experiment for test subjects after playing golf. The water content of the right, left, and chin except the forehead was significantly increased(p<0.05) after skin moisturize care. In addition, test result shows that 75% of test subjects indicated that skin pulling feeling was decreased and felt moisturize. Plus, most of them were satisfied with their skin status.

Characteristics of Environmental Solar Ultraviolet Irradiance

Sasaki, Masako,Oyanagi, Takehiko,Takeshita, Shu Korean Society of Photoscience 2002 Journal of Photosciences Vol.9 No.2

Direct, continuous, and accurate measurements of solar ultraviolet irradiance (290-400 nm: UVR) have been carried out since 1990, by using both band-spectral ultraviolet-B (290-320 nm: UV-B) and ultraviolet-A (320-400 nm: UV-A) radiometers at Tokai University in Hiratsuka, Japan (35$^{\circ}$N, 139$^{\circ}$E). From our observations, the following findings are provided: 1) an increasing trend in solar UV -B from Oct. 1990 to Sept. 2000; 2) a regional comparison of solar UVR in Japan; 3) the distinct characteristics of UV-B and UV-A irradiance, such as diffuse property, daily and seasonal variation; and 4) human body protection against solar UVR. An increasing 10-year trend in global solar UV - B in Hiratsuka corresponded to a decrease in the total ozone amount measured at Tsukuba (36$^{\circ}$N, 140$^{\circ}$E), giving supportive evidence for a direct link between these two parameters. Furthermore, a strong correlation was found between solar UV-B and total ozone amount from results of UVR measurements at four Tokai University monitoring stations dispersed throughout Japan. Additional results revealed different diffuse properties in global solar UV and in global solar total (300-3000 nm: Total) irradiances. For example, in the global UVR, the diffuse component was dominant: about 80 % independent of weather, with more than 60 % of global UV-B, and more than 50% of global UV-A with even a cloudless clear sky. On the other hand, the portion of the diffuse in the global total irradiance was very low, less than 10 % on a cloudless clear day. Daily and seasonal variations of UV -B and UV -A irradiances were found to be quite different, because of the marked dependence of UV -B irradiance on the atmospheric ozone amount. Moreover, UV -B irradiance showed large daily and seasonal variations: the ratio between maximum and minimum irradiances was more than 5. In contrast, the variation in UV-A was small: the ratio between maximum and minimum was less than 2. Three important facts are proposed concerning solar UVR protection of the human body: 1) the personal minimal erythema dose (MED); 2) gender based difference in MED values; and 3) proper colors for UVR protective clothing.

사람의 각질세포에서 UVB 유도에 따른 MMP-1의 발현 조절과MAPKs 인산화에 타임 추출물이 미치는 효과

정하나,정현주,신경희,김영선,문제현,이태훈 한국응용생명화학회 2018 Journal of Applied Biological Chemistry (J. Appl. Vol.61 No.4

Ultraviolet rays are electromagnetic waves with a shorter wavelength than visible light, and ultraviolet rays that pass through the ozone layer are the main cause of skin aging. Chronic exposure of skin tissue to ultraviolet light activates the Mitogenactivated Protein Kinases (MAPKs) signaling pathways in human keratinocytes, resulting in increased production of matrix metalloproteinases (MMPs). In this study, we investigated the herbal extracts from Jeju Island on the anti-aging effect in human keratinocytes (HaCaTs) by ultraviolet stimulation. We examined that herb extract from Jeju Island were decreased in anti-aging activity on measuring the level of MMP-1 gene and protein expression in ultraviolet-induced keratinocytes. As a result, it was confirmed that Thymus quinquecostatus extract (TQE) significantly reduced the expression of MMP-1 in a dose-dependent manner by UV irradiated HaCaTs. According to our data, TQE significantly attenuated UV-induced phosphorylation of the MAPKs signaling elements ERK1/2, JNK1/2 and p38 proteins. These results suggest that the MAPKs pathway may contribute to the inhibitory effect of TQE on UV-induced MMP-1 production in human keratinocytes. Our results suggest that TQE may be a protective agent against skin aging by preventing UV-induced MMP-1 production. 자외선은 가시 광선보다 파장이 짧은 전자기파이며, 오존층을통과하는 자외선이 피부 노화의 주요 원인이다. 피부 조직을 자외선에 만성적으로 노출 시키면 인간 각질 형성 세포에서Mitogen-activated Protein Kinases (MAPKs) 신호 전달 경로가활성화되어 매트릭스 metalloproteinases (MMPs) 생성이 증가한다. 본 연구에서는 제주도의 초본 추출물을 대상으로 자외선 자극을 통해 인간 각질 형성 세포(HaCaTs)의 항 노화 효과에 대해 조사 하였다. 우리는 자외선 유도 된 각질 형성 세포에서MMP-1 유전자와 단백질 발현 수준을 측정 하였으며 그 결과, Thymus quinquecostatus 추출물(TQE)은 자외선 조사된 HaCaT 세포에서 의해 농도 의존적으로 MMP-1의 발현을 유의하게 감소시키는 것으로 확인되었다. 또한, TQE는 MAPK 신호 전달요소 인 ERK1/2, JNK1/2 및 p38 단백질의 자외선 유도에 따른 인산화를 유의 적으로 감소시켰다. 이러한 결과는 MAPKs 경로가 인간 각질 세포에서 UV 유도 MMP-1 생산에 대한TQE의 억제 효과에 기여할 수 있음을 시사한다. 우리의 결과는 아마도 인간 각질형성 세포에서 TQE가 자외선 유도된MMP-1 생산을 억제하는 피부 노화 소재로 활용될 수 있음을시사한다.

Thickness Dependence of Ultraviolet-excited Photoluminescence Efficiency of Lumogen Film Coated on Charge-coupled Device

Chunxian Tao,Zhaoxia Han,Jun Ruan,Shunpeng Shu,Zhongrong Lu,Ruijin Hong,Dawei Zhang 한국광학회 2017 Current Optics and Photonics Vol.1 No.4

In order to investigate the ultraviolet-excited photoluminescence properties of phosphor coatings andtheir relationship to thickness, Lumogen coatings with different thicknesses were deposited on quartzsubstrates and charge-coupled device chips by thermal evaporation. The variation of the film thicknessaffected the crystallite size, surface roughness and fluorescence signal. It was found that the Lumogencoating with the thickness of 420 nm has the largest luminescent signal and conversion efficiency, andthe corresponding coated charge-coupled devices had the maximum quantum efficiency in the ultraviolet. These results provided one key parameter for improving the sensitivity of Lumogen coated charge-coupleddevices to ultraviolet light.

천연염재의 자외선 차단성능 연구

김월순,최인려 服飾文化學會 2004 服飾文化硏究 Vol.12 No.1

This study was carried out on the process of natural dye substances which can block ultraviolet rays without producing harmful substances by pollution, germs, etc. While making human body safe in contact, extracting Gardenia, Sappan wood, Radix scutellariae, Cromwell, Mugwort, Gallnut, Lac. Those are used for curing diseases, dyeing silk cloth with those extracts, and examining the color fastness, Ultraviolet protection. From this study, the following conclusion was produced. Brightness was lower in pre-mordanting than in post. And color difference showed that Radix scutellariae was the highest. Aluminum-mordanting showed a higher color difference than Fe. Colorfastness to washing was high in all samples, and the degree of color-changing by washing was the highest in the sample dyed by gardenia, pre-mordanted gallnut showed the highest degree. Colorfastness to perspiration was the highest in gardenia. UV-A test showed that all samples a high rate of 85% or higher compared with test white cloth. Especially, post-mordanted radix scutellariae, pre-mordanted gallnut and post-mordanted sappanwood showed a superior blocking rate.

증착 중 자외광 노광에 의한 산화 아연 박막의 특성 변화

김보석,백승재,Kim, Bo-Seok,Baik, Seung Jae 한국전기전자재료학회 2016 전기전자재료학회논문지 Vol.29 No.4

ZnO thin films have wide application areas due to its versatile properties as transparent conductors, wide-bandgap n-type semiconductors, gas sensor materials, and etc. We have performed a systematic investigation on ultraviolet-assisted CVD (chemical vapor deposition) method. Ultraviolet irradiation during the deposition of ZnO causes chemical reduction on the growing surface; which results in the reduction of the deposition rate, increase in the surface roughness, and decrease of the electrical resistivity. These effects produce larger characteristic variation with various deposition conditions in terms of surface morphology and optical/electrical properties compared to normal CVD deposited ZnO thin films. This versatile controllability of ultraviolet-assisted CVD can provide a larger processing options in the fabrication of nano-structured materials and flexible device applications.