• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.246-246
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• 2010

In this paper, we investigated the diffraction grating efficiency on AsSeS and Ag-doped amorphous chalcogenide Ag/AsSeS thin film for used to volume hologram. The Chalcogenide film thickness was 0.5um and Ag thin film was varied from 10nm and 20nm. Diffraction efficiency was obtained from (P:P) polarized Diode Pumped Solid State laser(DPSS, 532.0nm: 200mW) beam on AsSeS and Ag/AsSeS thin films. As a results, diffraction grating was not formed at AsSeS thin film but at Ag-doped AsSeS thin film, diffraction grating was formed well compare with the former.

• Proceedings of the Korean Magnestics Society Conference
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• 2010.06a
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• pp.40-40
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• 2010

• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.89.1-89.1
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• 2013

We present a multiwavelength study of the X-class flare, which occurred in active region (AR) NOAA 11339 on 3 November 2011. The EUV images recorded by SDO/AIA show the activation of a remote filament (located north of the AR) with footpoint brightenings about 50 min prior to the flare occurrence. The kinked filament rises-up slowly and after reaching a projected height of ~49 Mm, it bends and falls freely near the AR, where the X-class flare was triggered. Dynamic radio spectrum from the Green Bank Solar Radio Burst Spectrometer (GBSRBS) shows simultaneous detection of both positive and negative drifting pulsating structures (DPSs) in the decimetric radio frequencies (500-1200 MHz) during the impulsive phase of the flare. The global negative DPSs in solar flares are generally interpreted as a signature of electron acceleration related to the upward moving plasmoids in the solar corona. The EUV images from AIA $94{\AA}$ reveal the ejection of multiple plasmoids, which move simultaneously upward and downward in the corona during the magnetic reconnection. The estimated speeds of the upward and downward moving plasmoids are ~152-362 and ~83-254 km/s, respectively. These observations strongly support the recent numerical simulations of the formation and interaction of multiple plasmoids due to tearing of the current-sheet structure. On the basis of our analysis, we suggest that the simultaneous detection of both the negative and positive DPSs is most likely generated by the interaction/coalescence of the multiple plasmoids moving upward and downward along the current-sheet structure during the magnetic reconnection process. Moreover, the differential emission measure (DEM) analysis of the active region reveals presence of a hot flux-rope structure (visible in AIA 131 and $94{\AA}$) prior to the flare initiation and ejection of the multi-temperature plasmoids during the flare impulsive phase.

• Journal of IKEEE
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• v.15 no.2
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• pp.134-142
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• 2011

This paper describes a tripple-mode high-efficiency DC-DC buck converter. The DC-DC buck converter operate in PWM(Pulse Width Modulation) mode at moderate to heavy loads(100mA~500mA), in PFM(Pulse Frequency Modulation)at light loads(1mA~100mA), and in LDO(Low Drop Out) mode at the sleep mode(<1mA). In PFM mode DPSS(Dynamic Partial Shutdown Strategy) is also employed to increase the efficiency at light loads. The triple-mode converter can thus achieve high efficiencies over wide load current range. The proposed DC-DC converter is designed in a CMOS 0.18um technology. It has a maximum power efficiency of 96.4% and maximum output current of 500mA. The input and output voltages are 3.3V and 2.5V, respectively. The chip size is 1.15mm ${\times}$ 1.10mm including pads.

• Particle and aerosol research
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• v.18 no.4
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• pp.87-95
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• 2022

Currently, droplet protective screens (DPSs) are used to prevent the spread of respiratory diseases. As virus particles can maintain their infective in indoor environments, recent studies have investigated the risk of airborne transmission. However, the ability of DPSs to block airborne transmission has not been verified yet. In this study, the preventive ability of DPSs against droplet and airborne transmission was evaluated. Moreover, the effectiveness of a Portable air purifier (PAP) was investigated. According to results, in a simulated room where an infectious person spoke, the DPS blocked more than 90% of the micron-sized droplets (with a diameter larger than 1 ㎛) transmitted to the front of the infectious person. However, sub-micron droplets (with a diameter smaller than 1 ㎛) passed through the DPS and spread in a room. However, the PAP reduced the amount of both micron and sub-micron droplets transmitted to the front of the infectious person. When the PAP airflow direction was set from the DPS surface to the free space near the infectious person, improved prevention against droplet and airborne transmission was recorded. However, airborne transmission was accelerated when the PAP airflow direction was set from the free space to the DPS surface.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.205-207
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• 2008

The new process for hybrid silicon thin film transistor (TFT) using DPSS laser has been developed for realizing both low-temperature poly-Si (LTPS) TFT and a-Si:H TFT on the same substrate as a backplane of active matrix liquid crystal display. LTPS TFTs are integrated on the peripheral area of the panel for gate driver integrated circuit and a-Si:H TFTs are used as a switching device for pixel in the active area. The technology has been developed based on the current a-Si:H TFT fabrication process without introducing ion-doping and activation process and the field effect mobility of $4{\sim}5\;cm^2/V{\cdot}s$ and $0.5\;cm^2/V{\cdot}s$ for each TFT was obtained. The low power consumption, high reliability, and low photosensitivity are realized compared with amorphous silicon gate driver circuit and are demonstrated on the 14.1 inch WXGA+ ($1440{\times}900$) LCD Panel.

• New Physics: Sae Mulli
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• v.68 no.11
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• pp.1167-1172
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• 2018

Carbon nanotubes (CNTs) are structures of carbon atoms bonded together in hexagonal honeycomb shapes, with multi-walled CNTs having a very high thermal conductivity of $3000W/m{\cdot}K$ and single-walled CNTs having a conductivity of $6000W/m{\cdot}K$. In this work, the transmittance and the thermal diffusivity of a multi-walled carbon nanotube dispersion with a concentration of 1.5 M were measured using a single beam method, a dual beam method, and the thermal lens effect. The nonlinear optical coefficients were obtained by using the z-scan method, which moved the sample in the direction of propagation of the single laser beam, propagation and the thermal diffusivity was measured using a double laser beam. As a pump beam, a diode-pumped solid state (DPSS) laser with a wavelength of 532 nm and an intensity of 100 mW was used. As the probe beam, a He-Ne laser having a wavelength of 633 nm and an intensity of 5 mW was used. The experimental result shows that when the concentrations of the sample were 9.99, 11.10, 16.65, and 19.98 mM, the nonlinear absorption coefficients were 0.046, 0.051, 0.136 and 0.169 m/W, respectively. Also, the nonlinear refractive indices were 0.20, 0.51, 1.25 and $1.32{\times}10^{-11}m^2/W$, respectively, and the average thermal diffusivity was $1.33{\times}10^{-6}m^2/s$.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.275-276
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• 2011

We have investigated the holographic grating formation on Ag-doped amorphous chalcogenide As2Se3 thin films with Ag layer. The basic optical parameter which is a refractive index and extinction coefficent was taken by n&k analyzer. The source of laser was selected based on these parameter. Holographic gratings have been formed using He-Ne laser (wavelength: 632.8 nm) Diode Pumped Solid State laser (DPSS, wavelength: 532.0 nm) under [P:P] polarized the intensity polarization holography. The diffraction efficiency was obtained by +1st order intensity.

• Laser Solutions
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• v.16 no.3
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• pp.27-31
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• 2013

To engrave high-density circuit-line patterns in IC substrates, we applied a projection ablation technique in which a dielectric ($ZrO_2/SiO_2$) mask, a DPSS UV laser instead of an excimer laser, a refractive beam shaping optics and a galvo scanner are used. The line/space dimension of line patterns of the dielectric mask is $10{\mu}m/10{\mu}m$. Using a ${\pi}$ -shaper and a square aperture, the Gaussian beam from the laser is shaped into a square flap-top beam; and a telecentric f-${\theta}$ lens focuses it to a $115{\mu}m{\times}105{\mu}m$ flat-top beam on the mask. The galvo scanner before the f-${\theta}$ lens moves the beam across the scan area of $40mm{\times}40mm$. An 1:1 projection lens was used. Experiments showed that the widths of the engraved patterns in a buildup film ranges from $8.1{\mu}m$ to $10.2{\mu}m$ and the depths from $8.8{\mu}m$ to $11.7{\mu}m$. Results indicates that it is required to increase the projection ratio to enhance profiles of the engraved patterns.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.647-650
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• 2006

Low temperature polycrystalline silicon (LTPS) technology using a high power laser have been widely applied to thin film transistors (TFTs) for liquid crystal, organic light emitting diode (OLED) display, driver circuit for system on glass (SOG) and static random access memory (SRAM). Recently, the semiconductor industry is continuing its quest to create even more powerful CPU and memory chips. This requires increasing of individual device speed through the continual reduction of the minimum size of device features and increasing of device density on the chip. Moreover, the flat panel display industry also need to be brighter, with richer more vivid color, wider viewing angle, have faster video capability and be more durable at lower cost. Kornic Systems Co., Ltd. developed the $KORONA^{TM}$ LTP/GLTP series - an innovative production tool for fabricating flat panel displays and semiconductor devices - to meet these growing market demands and advance the volume production capabilities of flat panel displays and semiconductor industry. The $KORONA^{TM}\;LTP/GLTP$ series using DPSS laser and XeCl excimer laser is designed for the new generation of the wafer & FPD glass annealing processing equipment combining advanced low temperature poly-silicon (LTPS) crystallization technology and object-oriented software architecture with a semistandard graphical user interface (GUI). These leading edge systems show the superior annealing ability to the conventional other method. The $KORONA^{TM}\;LTP/GLTP$ series provides technical and economical benefits of advanced annealing solution to semiconductor and FPD production performance with an exceptional level of productivity. High throughput, low cost of ownership and optimized system efficiency brings the highest yield and lowest cost per wafer/glass on the annealing market.