• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.913-917
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• 2003

In the electronic components and devices fabrication, thin film resistors with low TCR(temperature coefficient of resistance) and high precision have been used over 3 GHz microwave in recent years. Ni-Cr alloys thin films resistors is one of the most commonly used resistive materials because it has low TCR and highly stable resistance. In this work, we fabricated thin film resistors using Evanohm alloys target(72Ni-20Cr-3Al-4Mn-Si) of s-type with excellent resistors properties by RF-sputtering. Also we reported best deposited conditions of thin film resistors for microwave to observe microstructure and electronic properties of thin film according to deposited conditions(between target and substrate, power supply)

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.193-193
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• 2010

HIPIMS(High sputtering impulse magnetron sputtering)은 수십 ${\mu}s$의 짧은 pulse 동안 수kw의 매우 높은 파워를 인가할 수 있어 밀도 $10^{13}/cm^3$ 이상의 고밀도 플라즈마 방전이 가능하여 스퍼터된 타겟 이온들의 이온화율이 매우 높은 특징을 가진다. HIPIMS를 통해 증착한 박막의 경우 매우 치밀한 조직을 가지고 있어 기존 DC, Pulsed DC, RF 증착을 통한 박막에 비해 우수한 물성을 보여준다. 본 실험에서는 대면적의 고품위 Al:ZnO 박막을 증착하기위하여 HIPIMS 증착법을 사용하였다. 1000mm폭 타겟상에서 균일한 증착을 위하여 Balanced B-field, Unbalanced field를 각각 인가하여 실험하였다. 시뮬레이션을 통하여 타겟 중심부와 가장자리의 자기장을 결정하였으며, target edge에서의 증착율과 cathode erosion 방지를 위하여 원형 트랙형으로 보조 자석을 설치하였다. $Al_2O_3$(2wt%)가 첨가된 planar target을 사용하였고, power는 700 W~2 kW, 그리고 pulse 폭은 $50-150 {\mu}s$정도로 변화시켜 가면서 상온에서 증착하였다. 플라즈마 가스로는 Ar만을 사용하여 두께는 60-100 nm정도로 증착하였다. Plasma emission monitoring을 통해 측정한 결과 Balanced B-field 에 비해 Unbalanced B-field 조건 에서 스퍼터된 이온들의 균일도가 우수하였으며 증착된 박막의 균일도 또한 증가하였다.

• Journal of Ocean Engineering and Technology
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• v.34 no.5
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• pp.371-376
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• 2020

Underwater acoustics, which is the study of the phenomena related to sound waves in water, has been applied mainly in research on the use of sound navigation and range (SONAR) systems for communication, target detection, investigation of marine resources and environments, and noise measurement and analysis. Underwater acoustics is mainly applied in the field of remote sensing, wherein information on a target object is acquired indirectly from acoustic data. Presently, machine learning, which has recently been applied successfully in a variety of research fields, is being utilized extensively in remote sensing to obtain and extract information. In the earlier parts of this work, we examined the research trends involving the machine learning techniques and theories that are mainly used in underwater acoustics, as well as their applications in active/passive SONAR systems (Yang et al., 2020a; Yang et al., 2020b; Yang et al., 2020c). As a follow-up, this paper reviews machine learning applications for the inversion of ocean parameters such as sound speed profiles and sediment geoacoustic parameters.

• Journal of agriculture & life science
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• v.45 no.6
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• pp.175-181
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• 2011

Effective Agrobacterium-mediated transformation of Trichoderma harzianum could be achieved using the $Al_2O_3$ particles-abraded mycelia pellets. Transformation efficiency, as percents for the number of hygromcin-resistant mycelia pellets out of total pellets tested, was about 20 in average for $Al_2O_3$ experiment. No transformed mycelium was obtained from the intact mycelia pellets. After second round of antibiotics selection, DNA integration of hygromycin resistant gene and the expression of target gene could be confirmed by PCR and RT PCR, respectively. This is the first report of Agrobacterium-mediated T. harzianum transformation.

• Advances in nano research
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• v.16 no.6
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• pp.531-548
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• 2024

The study focuses on using remote sensing to gather data about the Earth's surface, particularly in urban environments, using satellites and aircraft-mounted sensors. It aims to develop a classification framework for road targets using multi-spectral imagery. By integrating Convolutional Neural Networks (CNNs) with XGBoost, the study seeks to enhance the accuracy and efficiency of road target identification, aiding urban infrastructure management and transportation planning. A novel aspect of the research is the incorporation of quantum sensors, which improve the resolution and sensitivity of the data. The model achieved high predictive accuracy with an MSE of 0.025, R-squared of 0.85, RMSE of 0.158, and MAE of 0.12. The CNN model showed excellent performance in road detection with 92% accuracy, 88% precision, 90% recall, and an f1-score of 89%. These results demonstrate the model's robustness and applicability in real-world urban planning scenarios, further enhanced by data augmentation and early stopping techniques.

• Nuclear Engineering and Technology
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• v.53 no.6
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• pp.1970-1978
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• 2021

The aim of this study was to optimize the target, moderator, and collimator (TMC) in a neutron beam generator for the accelerator-based BNCT (A-BNCT) system. The optimization employed the Monte Carlo Neutron and Photon (MCNP) simulation. The optimal geometry for the target was decided as the one with the highest neutron flux among nominates, which were called as angled, rib, and tube in this study. The moderator was optimized in terms of consisting material to produce appropriate neutron energy distribution for the treatment. The optimization of the collimator, which wrapped around the target, was carried out by deciding the material to effectively prevent the leakage radiations. As results, characteristic of the neutron beam from the optimized TMC was compared to the recommendation by the International Atomic Energy Agent (IAEA). The tube type target showed the highest neutron flux among nominates. The optimal material for the moderator and collimator were combination of Fluental (Al₂0₃+AlF₃) with ⁶⁰Ni filter and lead, respectively. The optimized TMC satisfied the IAEA recommendations such as the minimum production rate of epithermal neutrons from thermal neutrons: that was 2.5 times higher. The results can be used as source terms for shielding designs of treatment rooms.

• Proceedings of the Korean Vacuum Society Conference
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• 2008.08a
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• pp.112-112
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• 2008

• Journal of the Korean Ceramic Society
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• v.51 no.5
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• pp.375-379
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• 2014

Nanocrystalline TiAlN coatings were prepared by reactively sputtering TiAl metal target with $N_2$ gas. This was done using a magnetron sputtering system operated in DC and ICP (inductively coupled plasma) conditions at various power levels. The effect of ICP power (from 0 to 300 W) on the coating microstructure, corrosion and mechanical properties were systematically investigated using FE-SEM, AFM and nanoindentation. The results show that ICP power has a significant influence on coating microstructure and mechanical properties of TiAlN coatings. With increasing ICP power, the coating microstructure evolved from the columnar structure typical of DC sputtering processes to a highly dense one. Average grain size of TiAlN coatings decreased from 15.6 to 5.9 nm with increasing ICP power. The maximum nano-hardness (67.9 GPa) was obtained for the coatings deposited at 300 W of ICP power. The smoothest surface morphology (Ra roughness 5.1 nm) was obtained for the TiAlN coating sputtered at 300 W ICP power.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.109-109
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• 2016

철을 보호하는 코팅막에 있어서 현재는 우수한 희생방식성을 가지는 아연(Zn)이 많은 분야에서 활용되고 있지만 성능 향상을 위해서는 코팅막의 두께 증가가 필연적이다. 동일한 두께 혹은 그 이하에서 더 나은 내식성을 가지는 코팅막을 개발하는 목적으로 알루미늄(Al)과 마그네슘(Mg)을 이용한 코팅막의 개발을 진행하고 있으며 이 발표에서는 Al과 Mg의 코팅막을 다층으로 제작하여 이전 실험의 Al-Mg 코팅 강판과 비교 하였을 때 어떠한 특성이 나타나는지를 확인하였다. Al-Mg 코팅층은 99.999%의 Al, 99.99%의 Mg target을 사용하여 스퍼터링을 이용하여 냉연강판 위에 코팅하였다. 증발물질과 기판과의 거리는 7cm 이며, 기판은 세척을 실시한 후 클리닝 챔버에 장착하고 ${\sim}10^{-5}Torr$ 까지 진공배기를 실시하였다. 클리닝 챔버가 기본 압력까지 배기되면 아르곤 가스를 주입하고 기판홀더에 -800 V의 직류 전압을 인가하여 약 30분간 글로우 방전 청정을 실시하였다. 기판의 청정이 끝나면 아르곤 가스를 차단하고 코팅 챔버로 시편을 이송 후 코팅층 성분의 구성형태에 따라 Al과 Mg을 코팅하였다. Al-Mg 코팅층은 $5{\mu}m$의 두께를 기준으로 계면의 코팅층이 각각 Al과 Mg이며 다층으로 구성된 코팅층을 제작하였다. 그리고 후속 공정으로 질소 분위기 $400^{\circ}C$에서 10분간 열처리를 하였다. Al-Mg 코팅층을 주사전자현미경(SEM)으로 관찰한 결과, 표면에서는 Al 또는 Mg의 결정성 구조를 보였으며 단면에서는 다층의 경계를 조금이지만 확인할 수 있었으며 글로우방전분광기(GDLS)를 통해 열처리 후에는 층의 구분이 모호해 지는 것을 확인 할 수 있었다. 그리고 XRD를 통하여 열처리 후 Al-Mg 합금상의 생성도 확인하였다. 또한 Al-Mg가 다층으로 코팅된 강판을 염수분무시험을 통해서 내부식 특성을 확인하였다. Al-Mg 코팅 강판의 염수분무시험 결과, 모든 제작된 코팅층에서 열처리 전 보다 열처리 후 3배 이상의 내식성의 향상효과를 확인할 수 있었다. 이러한 결과로부터 열처리에 의한 합금상 생성 그리고 Al-Mg 박막의 미세구조 변화가 강판의 내식성에 영향을 미치고 있다는 것을 확인할 수 있었지만 다층 제작이 미치는 영향에 대해서는 좀 더 연구가 필요한 것으로 판단된다.

• Proceedings of the IEEK Conference
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• 2003.11a
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• pp.493-496
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• 2003

Recently, Ryu et al. proposed a multiple target DOA tracking algorithm, which has good features that it has no data association problem and simple structure. But its performance is seriously degraded in the low signal-to-noise ratio. In this paper, a measurement fusion method is presented based on ML(Maximum Likelihood), and the new DOA tracking algorithm is proposed by incorporating the presented fusion method into Ryu's algorithm. The proposed algorithm has a better tracking performance than that of Ryu's algorithm, and it sustains the good features of Ryu's algorithm.