• Molecules and Cells
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• v.42 no.11
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• pp.794-803
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• 2019

Ultraviolet light (UV)-induced cellular response has been studied by numerous investigators for many years. Long noncoding RNAs (lncRNAs) are emerging as new regulators of diverse cellular process; however, little is known about the role of lncRNAs in the cellular response to UV treatment. Here, we demonstrate that levels of lncRNA-HOTTIP significantly increases after UV stimulation and regulates the UV-mediated cellular response to UV through the coordinate activation of its neighboring gene Hoxa13 in GC-1 cells (spermatogonia germ cell line). UV-induced, G2/M-phase arrest and early apoptosis can be regulated by lncRNA-HOTTIP and Hoxa13. Furthermore, lncRNA-HOTTIP can up-regulate ${\gamma}-H_2AX$ and p53 expression via Hoxa13 in UV-irradiated GC-1 cells. In addition, p53 has the ability to regulate the expression of both lncRNA-HOTTIP and Hoxa13 in vitro and in vivo. Our results provide new data regarding the role lncRNAs play in the UV response in spermatogenic cells.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.333-336
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• 2006

In general, polymer materials undergo degradation when exposed to ultraviolet radiation, which can cause dissociation of chemical bonds. FRP composites which are used in strengthening existing structure are usually adhered on the concrete surface, its mechanical properties as well as appearance such as color, surface conditions are affected by sunlight and expecially ultraviolet light. In this study, variations of tensile strength after exposure for certain period of time through accelerated exposure by Xe arc methods specified in KS F 2274 are measured in order to examine strength degradation characteristics of FRP composite. As a result of ultraviolet light test for FRP composite after accelerated exposure for 0, 500, 1000, 1500 hour, discoloration of FRP composite occurs according to the passage of time. But, few strength degradations of FRP composite are observed due to exposure of ultraviolet ray with an small variation of tensile strength.

• Journal of Convergence for Information Technology
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• v.8 no.1
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• pp.147-152
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• 2018

A polarizing spectacle lens having a perfect blocking of ultraviolet light and a partial blocking of blue light and having photochromic properties has been developed. It is a functional spectacle lens which can be used as a spectacle lens in the daytime, which plays a role of sunglass in a space with strong ultraviolet rays, dramatically reducing glare caused by late-night driving or reflected light. Photochromism was recovered in 0.5 second dark reaction and 3 seconds recovery time. The polarization function was about 95%. Ultraviolet rays were completely blocked and blue light was reduced by about 30%. A lens that combines photochromic and UV blocking and polarization functions is the first attempt at investigating the domestic market.

• Tribology and Lubricants
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• v.38 no.6
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• pp.247-254
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• 2022

Chemical mechanical polishing (CMP) is a hybrid surface-polishing process that utilizes both mechanical and chemical energy. However, the recently emerging semiconductor substrate and thin film materials are challenging to process using the existing CMP. Therefore, previous researchers have conducted studies to increase the material removal rate (MRR) of CMP. Most materials studied to improve MRR have high hardness and chemical stability. Methods for enhancing the material removal efficiency of CMP include additional provision of electric, thermal, light, mechanical, and chemical energies. This study aims to introduce research trends on CMP using ultraviolet (UV) light to these methods to improve the material removal efficiency of CMP. This method, photocatalysis-assisted chemical mechanical polishing (PCMP), utilizes photocatalytic oxidation using UV light. In this study, the target materials of the PCMP application include SiC, GaN, GaAs, and Ru. This study explains the photocatalytic reaction, which is the basic principle of PCMP, and reviews studies on PCMP according to materials. Additionally, the researchers classified the PCMP system used in existing studies and presented the course for further investigation of PCMP. This study aims to aid in understanding PCMP and set the direction of future research. Lastly, since there have not been many studies on the tribology characteristics in PCMP, research on this is expected to be required.

• Fashion & Textile Research Journal
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• v.21 no.2
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• pp.231-236
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• 2019

This study investigated the proper dyeing conditions, color fastness and functionality of wool fabrics dyed with Zizania latifolia Turcz. We also tried to improve light fastness through treatment with benzophenone ultraviolet absorber. The dyeing of wool fabrics using Zizania latifolia Turcz was good even without pretreatment or mordanting treatment. Optimal wool fabric dyeing conditions were colorant concentration of 200% (o.w.f.), dyeing temperature of $100^{\circ}C$, dyeing time of 80 minutes and a dye bath pH of 3. Color fastness of dyed wool fabrics to washing, rubbing, perspiration and light was 4-5, 5, 4-4-5 (acidic), 4-5 (alkaline) and 2 respectively. The results after treatment with ultraviolet absorber for improving the fastness of daylight were improved to 3-4 grade. The UV protection rate were increased after dyeing and the deodorization of ammonia gas improved to 98%. Bacterial reduction rate (Staphylococcus aureus) of wool fabrics was excellent at 99.9%. All dye fastness (except for light fastness) was excellent; in addition, the functionality of wool fabrics dyed with Zizania latifolia Turcz also improved. The results are expected to be applied to various fields because they indicate excellent results after treatment with ultraviolet absorber for improving the fastness of daylight.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04b
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• pp.139-142
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• 2000

Displacement current was generated in the light stimulus. Solution of azobenzene molecules (8A5H) have to character trans-to-cis. The Maxwell displacement current measuring technique has been applied for the investigation of azobenzene organic thin films under alternating photoirradiation with ultraviolet($\lambda_1$) and visible($\lambda_2$) light. also, As laser beam(630~670nm) investigate light response. As result, ultraviolet($\lambda_1$) and visible($\lambda_2$) light see photoisomerization response, but laser beam not appear photoisomerization in current that differ wave range reagent.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.3
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• pp.7-14
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• 2011

Many countries and researchers in the lighting field have focused on the LED light source as a solution to energy savings and environmental pollution. The LED light source consumes less power, has a long life and is highly economical. It is vibration and shock-resistant, and environment friendly as well. But LED lighting has some problems. In particular, the photobiological safety of LED light sources is emerging as an issue. Ultraviolet radiation from the LED light source emitted directly to the human body over a long period of time is harmful. In this paper, UV radiation from white LED was measured. Finally, the LED light source emits UV radiation, but it is relatively small when compared to others.

• Journal of the Korean institute of surface engineering
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• v.44 no.3
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• pp.89-94
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• 2011

In this study, the photocurrent characteristics of plasma sprayed $TiO_2$ coatings have been investigated according to additive transition metal (Fe, Mn, Nb powder) and heat treatment conditions. The plasma sprayed $TiO_2$ coatings by heat treatment at $400^{\circ}C$ and 90 min had the higher photocurrent at ultraviolet light, no photocurrent at visible light. The photocurrent of plasma sprayed $TiO_2$ coatings added by Fe, Mn, Nb (named by plasma sprayed $TiO_2$ composite coatings) was lower than that of plasma sprayed $TiO_2$ coatings at ultraviolet light, as was low in intensity ratio of XRD(101)/(110). and the atomic percentage of oxygen by plasma sprayed $TiO_2$ composite coatings was higher than that by plasma sprayed $TiO_2$ coatings. The photocurrent of plasma sprayed $TiO_2$ composite coatings in heat treatment at $400^{\circ}C$ and 90 min was higher than that of plasma sprayed $TiO_2$ coatings in same heat treatment conditions at ultraviolet and visible light, as was high in oxygen affinity by heat treatment.

• Current Optics and Photonics
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• v.2 no.4
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• pp.303-307
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• 2018

We propose a simple ultraviolet (UV) sensor consisting of a conventional single-mode optical fiber capped with an azobenzene-moiety-containing polymer. The UV light changes the dimensions of the azobenzene polymer, as well as the refractive index of the material. Incident light with a wavelength of 1550 nm was reflected at the fiber/polymer and polymer/air interfaces, and interference of the reflected beams resulted in spectral interference that shifted the wavelength by 0.78 nm at a UV input power of $2.5mW/cm^2$. The UV sensor's response to wavelength is nonlinear and stable. The response speed of the sensor is limited by detection noise, which can be improved by modifying the insertion loss of the UV sensor and the signal-to-noise ratio of the detection system. The proposed compact UV sensor is easy to fabricate, is not susceptible to electromagnetic interference, and only reacts to UV light.

• Journal of the Korean Physical Society
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• v.73 no.12
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• pp.1879-1883
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• 2018

We analyzed the deep-trap states of GaN/InGaN ultraviolet light-emitting diodes (UV LEDs) before and after electrical stress. After electrical stress, the light output power dropped by 5.5%, and the forward leakage current was increased. The optical degradation mechanism could be explained based on the space-charge-limited conduction (SCLC) theory. Specifically, for the reference UV LED (before stress), two sets of deep-level states which were located 0.26 and 0.52 eV below the conduction band edge were present, one with a density of $2.41{\times}10^{16}$ and the other with a density of $3.91{\times}10^{16}cm^{-3}$. However, after maximum electrical stress, three sets of deep-level states, with respective densities of $1.82{\times}10^{16}$, $2.32{\times}10^{16}cm^{-3}$, $5.31{\times}10^{16}cm^{-3}$ were found to locate at 0.21, 0.24, and 0.50 eV below the conduction band. This finding shows that the SCLC theory is useful for understanding the degradation mechanism associated with defect generation in UV LEDs.