• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.39-40
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• 2022

This study is intended to examine the curing effect of the combination of the bubble sheet on the concrete by analyzing the temperature profile and core strength of the simulated concrete structure. The test results relvealed that the average temperature of the concrete applying photothermal sheet overlapped with the double bubble sheet at the bottom was 23.5℃, which had the highest insulation and insulation effect compared to other types of surface insulation curing sheets, and the core strength increased by up to 56%.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.667-668
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• 2006

Usually nanosecond pulsing laser ablation of metal is under thermal effect. Many studies of the theoretical analysis and modeling to predict a result of laser ablation of metal are suggested on the basis of the photothermal mechanism. In this paper, we investigate the etching depth and laser fluence of laser ablation of copper films. We proposed the simplified SSB Model(Srinivasan-Smrtic-Babudp model) to study the photothermal effect of nanosecond pulsing laser ablation of copper thin metal. The experimental results were obtained by using the 355nm DPSS $Nd:YVO_4$ laser.

• Applied Chemistry for Engineering
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• v.32 no.3
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• pp.299-304
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• 2021

This study focuses on the preparation of acetaminophen (AP) imprinted functional biomaterials for a transdermal drug delivery using mung bean starch (MBS), polyvinyl alcohol (PVA), sodium benzoate (S) as a crosslinking agent, glycerol (GL) as a plasticizer, and melanin (MEL) as a photothermal agent. The prepared AP imprinted biomaterials were characterized using FE-SEM and their physical properties were evaluated. The photothermal effect and AP release property for functional biomaterials were examined with the irradiation of near infrared (NIR) laser (1.5 W/cm²). When the NIR laser was irradiated on functional biomaterials with/without the addition of MEL, the temperature of MEL added biomaterial increased from 25 ℃ to 41 ℃, whereas the biomaterial without MEL increased from 25 ℃ to 28 ℃. Results indicate that there is the photothermal effect of prepared biomaterial with the addition of MEL. Based on the results, AP release properties were evaluated using standard buffer solutions and artificial skin. It was found that AP release rates of MEL added AP loaded biomaterials were 1.2 times faster than those of MEL non-added AP loaded biomaterials when irradiating with NIR laser. We envision that the developed functional biomaterials can be utilized for an acute pain-killing treatment.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.1
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• pp.21-30
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• 2021

The purpose of this study is to investigate the antibacterial effects of indocyanine green (ICG) and near-infrared diode lasers on multispecies biofilms. Multispecies biofilms of Streptococcus mutans, Lactobacillus casei and Candida albicans were treated with different irradiation time using photosensitizer ICG and 808 nm near-infrared diode laser. Colony forming unit (CFU) was measured, and qualitative evaluation of biofilm was performed with confocal laser scanning microscopy (CLSM). Temperature measurement was conducted to evaluate photothermal effect. In the groups using ICG and diode laser, reduction in CFU was statistically significant, but the difference in antibacterial effect on L. casei and C. albicans with irradiation time was not significant, and similar results were confirmed with CLSM. Groups with ICG and diode laser showed higher temperature elevation than groups without ICG, and results of measured temperature were similar to the range of hyperthermia. In conclusion, ICG and near-infrared diode laser showed antibacterial effects on multispecies biofilms, but studies on protocol are necessary for clinical application.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.5
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• pp.871-876
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• 2019

We fabricated concave optical fiber tips using hydrofluoric acid solution and photothermal effect induced by $1.55{\mu}m$ wavelength laser applied to an optical fiber. The radius of curvature of the concave optical fiber tips fabricated with different applied laser power, etching time, and concentration of hydrofluoric acid was measured with an optical microscope. Then, we analyzed how the radius of curvature changes for those three variables. In addition, the reliability of the measurement method using a microscope was verified through a free spectral range(FSR) and a scanning electron microscope(SEM). Through this paper, the radius of curvature can be adjusted by the variables of the fabrication process of concave optical fiber tips; thus, it is overcoming the limitations of conventional optical fiber etching methods using hydrofluoric acid solutions.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.292.2-292.2
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• 2013

Graphene, a two-dimensional graphite material consisting of sp2-hybridized carbons. The properties of graphene such as extremely high carrier mobility, high thermal conductivity, low resistivity, large specific make it a promising materail of divices and material. Typically, poly (methyl methacrylate) (PMMA) is used when graphene transfer to other substrates. To remove PMMA on graphene, people used to dip the graphene into the acetone. However, it is known that the remove of PMMA on the graphene is difficult to completely using the acetone. Therefore, to remove the PMMA on the graphene surface, many research groups have employed various methods such as the thermal treatment, photothermal method, and other solvent. Nevertheless, a part of PMMA still remain on graphene surface. Usually, to observe the residual PMMA on graphene surface, topography of graphene surface scanned by atomic force microscopy is used. However, in that case, we can not distinguish PMMA and other particles. In this study, to confirm the residual PMMA on graphene surface, we employed novel measurement technique which is available to distinguish PMMA and other particles by means of photothermal effect.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.375-379
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• 1997

Pulsed Er:YAG and $CO_2$ lasers induced temperature rise of tissue are studied using axisymmetric, two-dimensional, and transient Pennes' bio-heat equation or the implications of skin resurfacing. Model results indicate that Er:YAG laser induced temperature has much higher but more shallow distribution in tissue than that of the $CO_2$ laser because of its higher absorption coefficient. The increase of repetition rate does not affect the temperature rise too much because these laser modalities have much shorter heat diffusion time than the temporal length of each off-pulse. This model works as a tool to understand the photothermal effect in the laser-tissue interaction.

• Journal of Photoscience
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• v.5 no.1
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• pp.39-43
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• 1998

Pulsed Er: YAG and CO$_2$ lasers induced temperature rise of tissue is studied using axisymmetric, two-dimensional, and transient Pennes bio-heat equation for elucidating the implications of skin resurfacing. Modeling indicates that Er:YAG laser induced temperature has much higher but more shallow distribution in tissue than that of the CO$_2$ laser because of much higher absorption coefficient. The increase of repetition rate does not much affect on temperature rise because these laser modalities have much shorter heat diffusion time than the temporal length of each off-pulse. This model works as a tool to understand the photothermal effect in the laser-tissue interaction.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.5
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• pp.731-736
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• 2017

In this paper, we report the fabrication of concave surface fiber tips for optical resonators. It was confirmed that the radius of curvature on fiber end can be controlled by introducing the hydrofluoric acid solution and the wavelength of $1.55{\mu}m$ laser which is absorbed well in the etchant to induce the photothermal effect. Using the microscope images, we observed the proposed concave fiber tip fabrication method is effective to make the controllable concave tips. We also observed changes in the size of the beam emitted from the tips with the various radius of curvature using the beam profiler. The authors believe that the proposed method will be applied to resonators for optical communications.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.11
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• pp.28-34
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• 2015

By incorporating a 966nm near infrared laser, we demonstrated bidirectional current triggering of between 0 and 10mA in a two-terminal planar device based on a highly resistive vanadium dioxide ($VO_2$) thin film grown by a pulsed laser deposition method. A two-terminal planar device, which had an electrode separation of $100{\mu}m$ and a $50{\mu}m-wide$ $VO_2$ conducting layer, was fabricated through ion beam-assisted milling and photolithographic techniques. A bias voltage range for stable bidirectional current triggering was determined by investigating the current-voltage curves of the $VO_2-based$ device in a current-controlled mode. Bidirectional current triggering of up to 10mA was realized by directly illuminating the $VO_2$ film with a focused infrared laser beam, and the transient responses of triggered currents were analyzed when the laser was modulated at various pulse widths and repetition rates. A switching contrast between off- and on-state currents was evaluated as ~3571, and the rising and falling times were measured as ~40 and ~20ms, respectively.