• Transactions on Electrical and Electronic Materials
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• 제14권1호
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• pp.24-27
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• 2013

In this paper, we investigated the effect of luminescence properties of various concentrations of magnesium-doped ZnS:Mn phosphor excited by plasma luminescence device. The PL intensity was evaluated in the range of 300~500 nm excitation wavelengths. We found the highest PL intensity of the phosphors excited by 365 nm and 450 nm was observed at Mg concentrations of 1.4 wt% and 0.8 wt%, respectively. In addition, an emission peak was distinguished at 580 nm wavelength. With increasing Mg dopant level, enhanced PL intensity was observed, which is possibly applicable to color converting materials by blue emission for white light sources. Finally, we evaluated the luminance properties of color converting ZnS:Mn,Mg phosphors with plasma blue light source. the white luminance of plasma light source with CIE(0.36,0.26) was established by color converting phosphors of ZnS:Mn with 0.8 wt% Mg.

• 한국전기전자재료학회논문지
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• 제29권2호
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• pp.69-74
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• 2016

In this study, we proposed an a-IGZO (amorphous In-Ga-Zn-O) TFT (thin-film transistor) with off-planed source/drain structure. Furthermore, two different electrode materials (ITO and Ti) were applied to the source and drain contacts for performance improvement of a-IGZO TFTs. When the ITO with a large work-function and the Ti with a small work-function are applied to drain electrode and source contact, respectively, the electrical performances of a-IGZO TFTs were improved; an increased driving current, a decreased leakage current, a high on-off current ratio, and a reduced subthreshold swing. As a result of gate bias stress test at various temperatures, the off-planed S/D a-IGZO TFTs showed a degradation mechanism due to electron trapping and both devices with ITO-drain or Ti-drain electrode revealed an equivalent instability.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회 2차
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• pp.45-52
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• 2010

Thermal properties of geomaterial are overlooked with other geomechanical properties. The transient line-source (TLS) method is one of the most used testing methods for measuring the thermal conductivity (K) and thermal diffusivity ($\alpha$) of materials. But more recently, Transient Plane-Source method was developed to measure these. It has several advantage of comparing with TSL method, but there has not been documented application in geomaterial. A Resistance Temperature Detector is used to construct sensor. For durability of Probe, Adopt a new technique that two probes are bonded in exact matching. For standard materials, such as glycerin, and ice the measured K and a values of these materials were generally within 2-5% from the standard values in the literature. This document present to evaluate the thermal properties of geomaterials and its application was tested for varying degree of saturation using the Transient Plane Source method. The result of this study suggests that it is an comparatively accurate method for simultaneously measuring thermal conductivity and thermal diffusivity and can identify the feasibility to geomaterial.

• 대한음성학회지:말소리
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• 제48호
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• pp.35-55
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• 2003

The aim of this study is to clarify the process of the sound changes of Japanese consonants (Dakuons) in the analysis of the transcriptions of Korean Source-Materials (i.e. Japanese textbooks for Korean and the records of travel in Japan) written in the 15-l8th centuries with the Korean writing system. Especially these records of travel in Japan are meaningful in that the process of change of Dakuon is shown in detail. The results are as follows. 1) In the 15th century, all Dakuons /g d z b/ had nasality. 2) The nasality of /z/ and /b/ disappeared in the 16th century. 3) The nasality of /d/ disappeared in the late 17th century.

• 한국표면공학회지
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• 제41권4호
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• pp.134-141
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• 2008

We have developed a numerical model for a remote ICP(inductively coupled plasma) system in 2D and 3D with gas distribution configurations and confirmed it by plasma diagnostics. The ICP source has a Cu tube antenna wound along a quartz tube driven by a variable frequency rf power source($1.9{\sim}3.2$ MHz) for fast tuning without resort to motor driven variable capacitors. We investigated what conditions should be met to make the plasma remotely localized within the quartz tube region without charged particles' diffusing down to a substrate which is 300 mm below the source, using the numerical model. OES(optical emission spectroscopy), Langmuir probe measurements, and thermocouple measurement were used to verify it. To maintain ion current density at the substrate less than 0.1 $mA/cm^2$, two requirements were found to be necessary; higher gas pressure than 100 mTorr and smaller rf power than 1 kW for Ar.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.411-412
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• 2007

EL (electro luminescent) is generally studied as a large size plane light emitting device and flexible light source because of it's simple manufacturing process. In this experiment, we manufactured flexible white emitting light source using Ni-foil with blue phosphor and color change materials. With increasing the thickness of color change material, the luminance of white emission is increased and the color coordinate of white color was shifted to pure white of (0.317,0.328) by strong emission of color change materials excited by blue excitation spectra. Also the luminance level was 30% higher in white emitting light device than blue only light source.

• 한국정밀공학회지
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• 제28권1호
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• pp.19-23
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• 2011

Recently, focused ion beam (FIB) applications have been investigated for the modification of VLSI circuit, the MEMS processing, and the localized ion doping, A multi aperture FIB system has been introduced as the demands of FIB applications for high speed and large area processing increase. A liquid metal ion source has problems, a large angular divergence and a metal contamination into a substrate. In this study, a gas ion source was introduced to replace a liquid metal ion source. The gas ion source generated inductively coupled plasma (ICP) in a quartz tube (diameter: 45 mm). Ar gas fed into the quartz was ionized by a 2 turned radio frequency antenna. The Ar ions were extracted by 2 extraction grids. The maximum extraction voltage was 10 kV. A numerical simulation was used to optimize the design of extraction grids and to predict an ion trajectory. As a result, the maximum ion current density was 38 $mA/cm^2$ and the spread of ion energy was 1.6 % for the extraction voltage.

• Journal of Korean Vacuum Science & Technology
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• 제4권3호
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• pp.73-77
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• 2000

Single crystal and polycrystalline Si thin films were doped with phosphorus by a 2-zone diffusion method to develop the low-resistivity polycrystalline Si electrode for a hemispherical grain. Solid phosphorus source was used in order to achieve uniformly and highly doped surface region of polycrystalline Si films having rough surface morphology. In case of 2-zone diffusion method, it is proved that the heavy doping near the surface area can be achieved even at a relatively low temperature. SIMS analysis revealed that phosphorus doping concentration in case of using solid P as a doping source was about 50 times as that of phosphine source at 750$^{\circ}C$. Also, ASR analysis revealed that the carrier concentration was about 50 times as that of phosphine. In order to evaluate the electrical characteristics of doped polycrystalline Si films for semiconductor devices, MOS capacitors were fabricated to measure capacitance of polycrystalline Si films. In ${\pm}$2 V measuring condition, Si films, doped with solid source, have 8% higher $C_{min}$ than that of unadditional doped Si films and 3% higher $C_{min}$ than that of Si films doped with $PH_3$ source. The leakage current of these films was a few fA/${\mu}m^2$. As a result, a 2-zone diffusion method is suggested as an effective method to achieve highly doped polycrystalline Si films even at low temperature.

• 반도체디스플레이기술학회지
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• 제18권2호
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• pp.78-81
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• 2019

In this study, we will analyze the design, development and application of these small drones using open source. These drones are used in flight exercises, aerial photography, and coding education. In the era of the fourth industrial revolution, such as the development of sensor technology, expansion of open source sharing, and application of artificial intelligence, Is expected to be able to demonstrate convergence. In this paper, we have studied the design and fabrication of small drones using open source. In the case of drones, various functions and differentiated materials are required depending on the application, and the future development of the unmanned mobile object, namely the drone, in which the creativity and the technology are combined with each other continues to be enhanced by the improvement of autonomy and artificial intelligence. Software-based architecture-based technologies have been developed in collaboration with embedded SWs that combine sensors, motors, and control systems. In hardware, it is customary to use a combination of materials and design to increase the freedom of design. It will be made in a free structure.

• Journal of Radiation Protection and Research
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• 제48권2호
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• pp.68-76
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• 2023

Background: In the process of discussion on the possibility of using radionuclide-contaminated soil and debris generated by radiation disasters, a strategy for the proper management of radiation exposure protection while considering the source of the contaminated materials is necessary. Materials and Methods: The radiological protection criteria that are likely to be applied to the source-related approach based on the International Commission on Radiological Protection recommendations and the International Atomic Energy Agency safety standards are summarized. We proposed five interpretations of radiation protection to contribute to the promotion of discussion on the possibility of using a part of low-level-radionuclide-contaminated soil and debris in the post-accident rehabilitation. Interpretations I to III are based on the idea of "using a reference level to protect the public in post-accident rehabilitation," whereas IV and V are based on the idea of "using the dose constraint to protect the public in the post-accident rehabilitation when the sources are handled in a planned activity." The former idea is subdivided into three based on the definition of the source, which is managed by the reference level, and the latter idea is divided into two depending on whether or not additional dose from using contaminated materials is deemed acceptable. Results and Discussion: To confirm the applicability of the five interpretations presented, we suggested the concrete values of protection criteria via two feasible cases. In this case study, we proposed radiation protection by the dose constraint based on the Interpretation IV and chose 1 mSv/yr for the public and 20 mSv/yr for workers dealing with radionuclide-contaminated materials. Conclusion: We concretely and systematically demonstrated how the concept of radiation protection can be applied to the process of discussion on the possibility of using radionuclide-contaminated materials within the framework of an international system of protection. This study's findings can provide necessary information to discuss the possibility of using radionuclide-contaminated materials as an alternative option for recovery and reconstruction after a radiation disaster from the viewpoint of radiation protection.