• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.1
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• pp.81-87
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• 2021

In this study the skin care system was designed and tested by introducing V-IPL(Variable-Intense Pulse Light) methods that allow various skin treatments. The discharge method, a new method of switching on the flash lamp sequentially according to the lesions, was used. Pulse shape control is implemented in the system using the conventional LC variable method and the switching method control method of the switching element. As a result, the pulse width could be varied up to 1[㎛] by using a microprocessor, and by turning on the flash lamp sequentially along the lesions the depth and width, the pulse shape and pulse shape could be more diverse. We could also make long pulses of up to 1~100[ms] in various pulse width. And the special differences between the existing system and the proposed system in this study are as follow. Existing system is one pulse(pulse width : 1~40ms) and proposed system is three pulse(pulse width : 1~100ms).

• Korean Journal of Food Science and Technology
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• v.34 no.4
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• pp.631-636
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• 2002

Lethality of high intensity light pulse on the pre-determined microbial populations has been investigated. Prior to the treatment, Lactobacillus plantarum, Lactobacillus brevis, Leuconostoc mesenteroides and Pediococcus pentosaceus were cultivated separately onto the surface of Lactobacilli MRS agar. Pre-determined microbial populations were applied to the test media and these sample were exposed to high intense light source with an exposure time ranging from 1 to $2500\;{\mu}s$. Results showed that at least 200 light pulses of $1\;{\mu}s$ duration were required to reduce L. Plantarum cells by 90% at 25 kV, the greater the number of light pulses, the larger the reduction in viable cell numbers. Viable cells of L. plantarum and the others were reduced by more than 5 and 6 log cycles at the upper exposure level of $750\;{\mu}s$, respectively. These study shows that pulsed light emissions can significantly reduce populations of lactic acid bacteria on exposed surface with exposure times. Killing efficiency for L. plantarum significantly increased with decreasing the distance between the lamp and the surface of samples.

• Journal of the Optical Society of Korea
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• v.13 no.1
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• pp.80-85
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• 2009

An experimental study of energy absorption and x-ray emission from ultrashort laser pulse irradiation of in-situ produced solid clusters has been performed. Silver clusters produced by a 30 mJ, 300 ps laser pulse were irradiated up to an intensity of $3{\times}10^{17}\;W/cm^2$ by a 70 mJ, 45 fs compressed laser pulse from the same Ti:sapphire laser. Absorption of the laser light exceeding 70% was observed, resulting in an x-ray yield (>1 keV) of ${\sim}60{\mu}J$ pulse. This may constitute a much simpler means of intense x-ray generation using ultrashort laser pulses as compared to the irradiation of structured / pre-deposited cluster targets, and it offers higher x-ray conversion efficiency than that from gas clusters and planar solid targets.

• Journal of the Microelectronics and Packaging Society
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• v.27 no.4
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• pp.113-117
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• 2020

In this paper, We investigated the effect of heat treatment process using photo-thermal effect in order to improve mechanical properties of nanostructure on polymer films made by nanoimprint process with hybrid resin. Nanostructures which have a low refractive characteristic were fabricated by UV nanoimprint and after that heat treatment was performed using IPL (intense pulsed light) under process condition of 550 V voltage, pulse width 5 ms, frequency 0.5 Hz. The transmittance and mechanical property of fabricated nanostructure films were evaluated to observe changes in the pattern transfer rate and mechanical properties of nanostructures. The transmittance of the nanostructure was measured at 97.6% at 550 nm wavelength. Nanoindentation was performed to identify improved anti-scatch properties. Result was compared by the heat source. In case of post treatment with IPL, hardness was 0.51 GPa and in the case of hotplate was 0.27 GPa, resulting the increase of hardness of 1.8 times. Elastic modulus of IPL treated sample was 5.9GPa and Hotplate treated one was 4GPa, showing the 1.4 time increase.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.293.1-293.1
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• 2016

Various materials including conductive, dielectric, and semi-conductive materials, constitute suitable candidates for printed electronics. Metal nanoparticles (e.g. Ag, Cu, Ni, Au) are typically used in conductive ink. However, easily oxidized metals, such as Cu, must be processed at low temperatures and as such, photonic sintering has gained significant attention as a new low-temperature processing method. This method is based on the principle of selective heating of a strongly absorbent film, without light-source-induced damage to the transparent substrate. However, Cu nanoparticles used in inks are susceptible to the growth of a native copper-oxide layer on their surface. Copper-oxide-nanoparticle ink subjected to a reduction mechanism has therefore been introduced in an attempt to achieve long-term stability and reliability. In this work, a flash-light sintering process was used for the reduction of an inkjet-printed Cu(II)O thin film to a Cu film. Using a photographic lighting instrument, the intensity of the light (or intense pulse light) was controlled by the charged power (Ws). The resulting changes in the structure, as well as the optical and electrical properties of the light-irradiated Cu(II)O films, were investigated. A Cu thin film was obtained from Cu(II)O via photo-thermal reduction at 2500 Ws. More importantly, at one shot of 3000 Ws, a low sheet resistance value ($0.2527{\Omega}/sq.$) and a high resistivity (${\sim}5.05-6.32{\times}10^{-8}{\Omega}m$), which was ~3.0-3.8 times that of bulk Cu was achieved for the ~200-250-nm-thick film.

• Journal of the Optical Society of Korea
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• v.20 no.1
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• pp.135-139
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• 2016

I propose a vector passive harmonic mode-locked fiber laser based on topological insulator Bi2Se3 interacting with a fiber taper with a diameter of 7 μm. The particles of topological insulator are deposited uniformly onto the fiber taper with light pressure effect. By incorporating the fabricated saturable absorber into an Er-doped fiber laser cavity, stable mode-locked fiber is obtained. Due to the intense evanescent field of the fiber taper, strong confinement of light enhances the nonlinearity of the laser cavity, and passive harmonic mode-locking is performed. I observe a maximum harmonic mode-locking of 356th, corresponding to a frequency of 3.57 GHz. The pulse duration is 824 fs, and the full width at half maximum of the spectrum is about 8.2 nm. The polarization dependent loss of the saturable absorber is ~ 2.5 dB in the wavelength range of the C band. As the cavity contains no other polarization dependent device, the mode-locked laser is functioning in the vector state. The harmonic order vs pump power is investigated. To the best of our knowledge, this report is the highest frequency mode-locked fiber laser based on Bi2Se3. Experimental results indicate that the topological insulator Bi2Se3 functioning with a thin fiber taper is effective for vector harmonic mode-locking.

• The Korean Society of Law and Medicine
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• v.15 no.1
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• pp.35-57
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• 2014

Recently, there has been fierce argument between oriental and western doctors in the medical field. The use of medical devices has particularly come to the fore lately. Appropriate medical devices are required to diagnose and treat patients' conditions or illnesses accurately. At issue recently in medical device sector are diagnostic instruments using radiation, magnetic resonance imaging, ultrasound, IPL(Intense Pulse Light), and instruments used for tonometry. Relating to this issue, Association of Korean Oriental Medicine and The Association of Korean Medicine are sharply opposed. It is predicted that more accusations of this kind will be seen in the future. As oriental medicine contends, ultrasonic imaging itself seems to cause no harm to humans and its use may have an advantage for national health. The use of western diagnostic equipment can expand the diagnostic range of oriental doctors. However, unless new legislation is made, it is against the law for oriental doctors to use this equipment. Both law and medical science require grounds and predictability on the correctness of a decision and all of its consequences. Additionally, oriental medicine's use of ultrasounds and other medical devices should be established by standards and grounds which make same the diagnosis with repetition. Therefore, the scope of oriental medicine can be expanded following a revision of the Oriental Medicine Promotion Act and it is estimated that the state of national health will be greatly improved by the mutual respect of both sides of the health profession.

• Journal of The Korean Ophthalmological Society
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• v.59 no.11
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• pp.1097-1102
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• 2018

Purpose: To report a case of toxic optic neuropathy caused by chlorfenapyr ingestion accompanied by central nervous system involvement. Case summary: A 44-year-old female visited our clinic complaining of reduced visual acuity in both eyes for 7 days. She had ingested a mouthful of chlorfenapyr for a suicide attempt 2 weeks prior to the visit. Gastric lavage was performed immediately after ingestion at the other hospital. Her best-corrected visual acuity was finger count 30 cm in the right eye and hand motion in the left eye. Both pupils were dilated by 5.0 mm and the response to light was sluggish in both eyes. A relative afferent pupillary defect was detected in her left eye. Funduscopy revealed optic disc swelling in both eyes. Magnetic resonance imaging of the brain showed a symmetric hyper-intense signal in the white matter tract including the internal capsule, corpus callosum, middle cerebellar peduncle, and brainstem. The patient was diagnosed with toxic optic neuropathy induced by chlorfenapyr ingestion, and underwent high-dose intravenous corticosteroid pulse therapy. Three days later, the best-corrected visual acuity was no light perception in both eyes. Three months later, optic atrophy was observed in both eyes. Optical coherence tomography revealed a reduction in the thicknesses of the retinal nerve fiber layer and ganglion cell and inner plexiform layer in the macular area. Conclusions: Ingestion of even a small amount of chlorfenapyr can cause severe optic nerve damage through the latent period, despite prompt lavage and high-dose steroid treatment.