• Journal of the Optical Society of Korea
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• 제13권1호
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• pp.15-21
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• 2009

High-order harmonic generation from a solid surface affected by the contrast of a laser pulse was studied using an oscillating mirror model. High-order harmonics generated from solid surfaces have unusual properties such as spectral redshift, and an intensity difference between even- and odd-order harmonics which is not reported for high-order harmonics generated by a gas medium. We confirmed that high-order harmonics from solid surfaces have selectivity of polarization as well as cut-off extension and the enhancement of conversion efficiency proportional to laser intensity. And the principle of operation and the characteristics of a plasma mirror system developed for achieving high contrast laser pulses to pursue the experimental realization of high-harmonic generation from solid surfaces are reported. Energy fluence on the plasma mirrors is tunable between $10\;J/cm^2$ and $1000\;J/cm^2$ and around 1000 shots are available before the plasma mirrors require replacement.

• Nuclear Engineering and Technology
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• 제56권1호
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• pp.70-77
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• 2024

A low energy ion irradiation system based on the deuterium arc ion source with a high perveance of 1 µP for a single extraction aperture has been successfully developed for the investigation of ion irradiation on plasma-facing components including the first mirror of plasma optical diagnostics system. Under the optimum operating condition for mirror testing, the ion source has a beam energy of 200 eV and a current density of 3.7 mA/cm². The ion source comprises a magnetic cusp-type plasma source, an extraction system, a target system with a Faraday cup, and a power supply control system to ensure stable long time operation. Operation parameters of plasma source such as pressure, filament current, and arc power with D₂ discharge gas were optimized for beam extraction by measuring plasma parameters with a Langmuir probe. The diode electrode extraction system was designed by IGUN simulation to optimize for 1 µP perveance. It was successfully demonstrated that the ion beam current of ~4 mA can be extracted through the 10 mm aperture from the developed ion source. The target system with the Faraday cup is also developed to measure the beam current. With the assistance of the power control system, ion beams are extracted while maintaining a consistent arc power for more than 10 min of continuous operation.

• 한국해양생명과학회지
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• 제8권2호
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• pp.150-159
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• 2023

수인성 질산 노출에 대한 향어의 독성 영향을 확인하기 위해 96시간 동안 0, 4, 20, 100, 500 및 2,500 mg NO₃^-/L의 수인성 질산에 노출을 실시하였다. 질산 96시간 급성 노출에 의한 향어의 반수치사농도(LC50)는 1,433.54 mg NO₃^-/L로 나타났다. 혈액학적 성상을 통해 수인성 질산 노출이 향어에게 미치는 생리학적 변화를 평가하였으며, RBC count는 유의적인 감소를 나타내었다(p < 0.05). 혈장 무기성분을 통해 수인성 질산 노출에 따른 향어의 이온 조절 능력 변화를 평가하였으며, 혈장 무기성분에서 calcium과 magnesium은 유의적으로 감소하였다(p < 0.05). 혈장 유기성분을 통해 수인성 질산 노출로 인한 향어의 건강도와 스트레스 상태를 평가하였으며, 혈장 유기성분인 glucose는 유의적인 증가를 나타내었다(p < 0.05). 혈장 효소성분을 통해 수인성 질산 노출로 인한 간 손상도 및 효소 활성의 변화를 평가하였으며, 혈장 효소성분인 AST, ALT 및 ALP는 높은 수준의 수인성 질산 노출에서 유의적으로 감소하였다(p < 0.05). 본 연구의 결과는 C. carpio nudus에 대한 수인성 질산 노출이 생존율, 혈액학적 성상 및 혈장성분에 독성으로 영향을 미칠 수 있음을 의미한다.

• Journal of the Optical Society of Korea
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• 제16권1호
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• pp.80-84
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• 2012

A high reflectance mirror, which has very low absorption and scattering loss, was coated onto a crystalline substrate by ion beam sputtering and then annealed at $450^{\circ}C$. We carefully selected the mirror coating material, and designed the high reflectance mirror, in order to avoid UV degradation which comes from the He-Ne plasma. We measured the surface roughness of the Zerodur substrate using phase shift interferometry and atomic force microscopy, and compared it with the TIS scattering of the mirror. The cavity ring-down method was used to measure the absorption of the mirror, and the thin film structure was correlated to its results. We also compared the optical properties of coated mirrors before and after annealing.

• 전자공학회논문지A
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• 제33A권10호
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• pp.98-106
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• 1996

A thin film of aluminum for ultra large scale integrated circuits metalization has been deposited on TiN and SiO$_{2}$ substrates by plasma assisted chemical vapor deposition using DMEAA (dimenthylethylamine alane) as a precursor. The effects of plasma on surface topology and growth characteristics were investigated. Thermal CVD Al could not be got continuous films on insulating subsrate such as SiO$_{2}$. However, it was found that Al films could be deposited on SiO$_{2}$ substate without any pretreatments by the hydrogen plasma for pyrolysis of DMEAA. Compared to the thermal CVD, PACVD films showed much better reflectance and resistance on TiN and SiO$_{2}$ substrate. We obtained mirror-like PACVD Al film of 90% reflectance and resistance on TiN and SiO$_{2}$ substrates. We obtained mirror-like PACVD Al film of 90% reflectance on TiN substrate. Excellent conformal step coverage was obtained on submicron contact holes ;by the PACVD blanket deposition.

• 한국어병학회지
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• 제35권1호
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• pp.65-75
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• 2022

Mirror carp, Cyprinus carpio nudus (weight 26.2±3.1 g, length 11.8±0.5 cm) were exposed to waterborne total ammonia nitrogen (TAN) at 0, 2, 4, 8, 16, 32, 64 and 128 mg TAN/L. The lethal concentration 50 (LC₅₀) of mirror carp, C. carpio nudus exposed to waterborne ammonia was 60.38 mg TAN/L. The red blood cell (RBC) count was significantly reduced by ammonia exposure, whereas there was no significant changes in the hemoglobin concentration and hematocrit value. In the plasma components, glucose, total protein, aspartate aminotransferase (AST) and alkaline phosphatase (ALP) were significantly increased by ammonia exposure. The results of this study suggest that the ammonia exposure to C. carpio nudus affects the survival rates, hematological parameters and plasma components as toxicity.

• 한국진공학회지
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• 제10권1호
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• pp.98-103
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• 2001

차세대 평판 디스플레이로서 플라즈마표시기(Plasma Display Pannel, PDP)는 현재 350 $\textrm{cd/cm}^2$의 휘도와 l lm/W 정도의 효율을 갖는 AC형 PDP가 개발되어 있으나, 음극선관(CRT)의 피크 휘도가 700 $\textrm{cd/cm}^2$, 효율이 수 1 m/W인 것을 감안하면 음극선관을 대체할 수 있는 표시기가 되기 위해서는 PDP의 휘도와 효율을 더욱 개선시킬 필요가 있다. 반사형 AC-PDP셀 내에서 가스 방전으로 발생된 진공 자외선(Vacuum Utraviolet, VUV) 중 배면판 쪽으로 진행되는 부분은 형광체를 여기시켜 가시광을 발생시키게 되지만, 전면판 쪽으로 진행되는 부분은 발광에 사용되지 못하고 있다. 본 연구에서는 PDP 셀 전면판의 유전체와 보호막 사이에 VUV를 반사시킬 수 있는 다이크로익 미러(Dichroic mirror)를 증착함으로써 셀 내의 VUV 이용 효율을 증가시켜 휘도와 효율을 향상시킬 수 있는 방법을 제안하였다. 다이크로익 미러를 정확하게 설계하기 위해서 미러에 사용되는 $MgF_2$, $LaF_3$, MgO 박막의 VUV 영역에서의 광학 계수(Optical Constant)를 실험과 시뮬레이션을 이용한 광도 측정법(Photometric method)을 통해서 구하였다 (1). 이 값들을 이용해서 플라즈마 표시기의 패널 방전에서 방출되는 빛의 휘도를 결정짓는 가장 중요한 요소인 147nm 부근의 진공자외선을 반사시킬 수 있는 다이크로익 미러를 설계하였다. 다이크로익 미러는 전자빔 증착기 (I-beam evaporator)를 이용하여 증착되었고, 박막의 광학 계수 결정을 위한 반사도(Reflectance), 투과도(Transmittance) 측정과 다이크로익 미러의 반사도 측정은 Reflectometer를 이용해 측정하였다. 패널 실험은 동일한 패널 내에 반쪽 면에만 다이크로익 미러를 증착시켜 방전 전압에 따른 휘도와 효율을 미러가 없는 면과 동일 조건하에 비교 측정하였다. 여러 방전 조건하에서 다이크로익 미러를 AC-PDP에 적용한 경우가 그렇지 않은 경우보다 휘도와 효율이 약 20-30% 정도 증가함을 확인하였다.

• JSTS:Journal of Semiconductor Technology and Science
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• 제1권2호
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• pp.132-139
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• 2001

We considered the uniformity of fabricated micromirror arrays by characterizing the fabrication process and calculating the appropriate driving voltages of micromirrors used as virtual photomask in maskless photolithography. The uniformity of the micromirror array in terms of driving voltage and optical characteristics is adversely affected by factors, such as the air gap between the bottom electrode and the mirror plate, the spring shape and the deformation of the mirror plate or torsion spring. The thickness deviation of the photoresist sacrificial layer, the misalignment between mirror plate and bottom electrode, the aluminum deposition condition used to produce the spring and the mirror plate, and initial mirror deflection were identified as key factors. Their importance lies in the fact that they are related to air gap deviations under the mirror plate, asymmetric driving voltages in left and right mirror directions, and the deformation of the Al sring or mirror plate after removal of the sacrificial layer. The plasma ashing conditions used for removing the sacrificial layer also contributed to the deformation of the mirror plate and spring. Driving voltages were calculated for the pixel operation of the micromirror array, and the non-uniform characteristics of fabricated micromirrors were taken into consideration to improve driving performance reliability.

• Nuclear Engineering and Technology
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• 제56권2호
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• pp.451-462
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• 2024

In order to optimize the operational safety and reliability of the upper launcher for the CFETR ECRH system, a design of the launcher based on the remote steering concept is currently being carried out for comparison with the front steering equivalent. This paper presents the remote steering system's conceptual design and simulation analysis. A Square Corrugated Waveguide (SCW) of 65 × 65 mm has been designed with an optimized length of 9.35 m. By changing the relative length of the waveguide, the transmission efficiency of the SCW is optimized within the range of steering angles ±12°. Different error factors are investigated in detail, and corresponding acceptable error ranges are provided. Considering these error factors and ignoring ohmic losses and thermal effects, the relative transmission efficiency of the SCW is estimated to be >98 % within the steering angle range. A matching steering unit for the SCW is designed, which consists of an ellipsoidal focusing mirror and a steerable flat mirror. The detailed design of the steerable mirror motion trajectory is presented. Also, the influence of the possible beam incident errors caused by the steering unit on the transmission efficiency is analyzed in detail.

• 한국수산과학회지
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• 제54권6호
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• pp.954-964
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• 2021

Mirror carp Cyprinus carpio nudus (weight 42.0±3.8 g, length 14.3±0.4 cm) were exposed to different concentrations of waterborne copper (0, 100, 200, 400, 800, and 1,600 ㎍ Cu²⁺·L^-1) at 20.3℃ for 96 h. The lethal concentration 50 of waterborne copper was 1,176.45 ㎍ Cu²⁺·L^-1. Among hematological parameters, red blood cell count was significantly decreased, whereas there were no significant changes in the hemoglobin concentration and hematocrit value. Among the inorganic plasma components, calcium was significantly decreased following copper exposure. Conversely, organic plasma components such as glucose and total protein were significantly increased. Similarly, enzymatic components, such as aspartate transaminase, alanine transaminase, and alkaline phosphatase, were also significantly increased. These findings suggest that the copper exposure is detrimental to the survival rates and physiology of C. carpio nudus.