• International journal of advanced smart convergence
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• 제2권2호
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• pp.16-18
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• 2013

In this paper, we develop a method to design a flexible thin film audio systems utilizing Polyvinylidene fluoride. The system we designed showed the properties of increased transparency and sound pressure levels. As an input terminal transparent oxide thin film is adopted. In order to provide dielectric insulation, a transparent insulating oxide thin film is coated to obtain double -layered structure. In the range of visible light, the output from the output of the system showed an increased and improved sound pressure level. The piezoelectric polymer film of polyvinylidene fluoride (PVDF) is used to produce mechanical vibration due to the applied electrical voltage signal. An analog electric voltage signal is transformed into sound waves in the audio system.

• Transactions on Electrical and Electronic Materials
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• 제14권6호
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• pp.304-307
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• 2013

Reverse engineering of semiconductor devices utilizes delayering processes, in order to identify how the interconnection lines are stacked over transistor gates. Cu metal has been used in recent fabrication technologies, and de-processes becomes more difficult with the shrinking device dimensions. In this article, reverse engineering technologies to reveal the Cu interconnection lines and Cu via-plugs embedded in dielectric layers are investigated. Stacked dielectric layers are removed by $CF_4$ plasma etching, then the exposed planar Cu metal lines and via-plugs are selectively delineated by wet chemical solution, instead of the commonly used plasma-based dry etch. As a result, we have been successful in extracting the layouts of multiple layers within a system IC, and this technique can be applicable to other logic IC, analog IC, and CMOS IC, etc.

• E2M - 전기 전자와 첨단 소재
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• 제10권8호
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• pp.783-793
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• 1997

A VLSI implementation of a self-learning neural network integrated circuits using a linearity synapse transistor is investigated. The thickness dependence of oxide current density stress current transient current and channel current has been measured in oxides with thicknesses between 41 and 112 $\AA$, which have the channel width $\times$ length 10 $\times$1${\mu}{\textrm}{m}$, 10 $\times$ 0.3${\mu}{\textrm}{m}$ respectively. The transient current will affect data retention in synapse transistors and the stress current is used to estimate to fundamental limitations on oxide thicknesses. The synapse transistor has represented the neural states and the manipulation which gaves unipolar weights. The weight value of synapse transistor was caused by the bias conditions. Excitatory state and inhitory state according to weighted values affected the drain source current.

• International Journal of Internet, Broadcasting and Communication
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• 제6권1호
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• pp.13-15
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• 2014

We develop a method to fabricate a flexible thin film audio systems using polyvinylidene fluoride(PVDF). The system we designed showed the properties of increased flexibility, transparency, and sound pressure levels. As an input port of two terminals, transparent oxide thin film with a low resistivity is adopted. In order to provide dielectric insulation, a transparent insulating oxide thin film is coated to obtain double-layered structure. In the range of visible light, the output from the output of the system showed a increased and improved sound pressure level. The piezoelectric polymer film of PVDF is used to produce mechanical vibration due to the applied electrical voltage signal. An analog electric voltage signal is transformed into sound waves in the audio system.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1998년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Spring 1998
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• pp.391-398
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• 1998

To understand the current seismic activity and regional tectonic status in and around Gyeongsang basin, Korea Institute of Geology, Mining, and Materials(KIGAM) has performed the earthquake monitoring around the Gyeongsang basin since early 1980's with portable analog seismic instruments for about two months every year. As a part of POSEIDON project, Korea-Japan joint observation around gyeongsang basin in 1991 and 1992, was performed using by temporary seismic station. KIGAM has been continuously operated nine short-period 3-components digital seismic stations since the end of 1994. During the observation period, 247 earthquakes were analyzed and their magnitude was less than 4.5. In general, we could not find any relationship between seismic activity and known surface geological features. But the epicenters were rather concentrated with NW-SE direction. The most active seismicity was found in Gyeongbuk Gyeongjugun Seokeupri and Hyodongri, and Yeongilgun Janggiri and Guryongpo in land, and in three region along the east coast which are 10km and 30km east off from Gampo and 30km east off from Jongja in offshore.

• Journal of Radiation Protection and Research
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• 제42권1호
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• pp.21-25
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• 2017

Background: We are developing L-band and S-band microwave dielectric absorption systems aiming novel dosimetry using DNAs, such as plasmid DNA and genomic DNA, and microwave technology. Materials and Methods: Each system is composed of a cavity resonator, analog signal generator, circulator, power meter, and oscilloscope. Since the cavity resonator is sensitive to temperature change, we have made great efforts to prevent the fluctuation of temperature. We have developed software for controlling and measurement. Results and Discussion: By using this system, we can measure the resonance frequency, f, and ${\Delta}Q$ (Q is a dimensionless parameter that describes how under-damped an oscillator or resonator is, and characterizes a resonator's bandwidth relative to its center frequency) within about 3 minutes with high accuracy. Conclusion: This system will be expected to be applicable to DNAs evaluations and to novel dosimetric system.

• 마이크로전자및패키징학회지
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• 제26권1호
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• pp.1-7
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• 2019

Recently, memristor (anion-based memristor) is referred to as the fourth circuit element which resistance state can be gradually changed by the electric pulse signals that have been applied to it. And the stored information in a memristor is non-volatile and also the resistance of a memristor can vary, through intermediate states, between high and low resistance states, by tuning the voltage and current. Therefore the memristor can be applied for analogue memory and/or learning device. Usually, memristive behavior is easily observed in the most transition metal oxide system, and it is explained by electrochemical migration motion of anion with electric field, electron scattering and joule heating. This paper reports the latest trends and issues of anion-based memristor.

• 마이크로전자및패키징학회지
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• 제30권3호
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• pp.83-87
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• 2023

전자 및 반도체 기술 분야에서는 Si를 대체할 혁신적인 반도체 소재 연구가 활발하게 진행 중이다. 그러나 대체 소재에 대한 연구는 진행 중이지만 2차원 물질을 채널로 사용하는 트랜지스터의 구성요소, 특히 기생 저항과 RF(고주파) 응용 프로그램과의 관계에 대한 연구는 매우 부족한 편이다. 본 연구는 이러한 부족한 부분을 메우기 위해 다양한 트랜지스터 구조에 중점을 두고 전기적 성능에 미치는 영향을 체계적으로 분석하였다. 연구 결과, Access 저항과 Contact 저항이 반도체 소자 성능 저하의 주요 요인 중 하나로 작용함을 확인하였으며, 특히 고도로 scaling down된 경우 그 영향이 더욱 두드러지는 것을 확인하였다. 고주파 RF 소자에 대한 수요가 계속해서 증가함에 따라 원하는 RF 성능을 달성하기 위한 소자 구조 및 구성 요소를 최적화하기 위한 가이드라인을 수립하는 것은 매우 중요하다. 본 연구는 2차원 물질을 채널로 사용하는 다음 세대 RF 트랜지스터의 설계 및 개발에 도움이 될 수 있는 구조적 가이드라인을 제공함으로써 이 목표에 기여할 수 있다.

• 한국산학기술학회논문지
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• 제22권6호
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• pp.583-590
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• 2021

본 연구는 아날로그 3D펜의 디지털화에 대한 연구이다. 디지털은 항상성과 변형가능성, 결합성, 재생산성 그리고 보관의 편리성 등의 특징이 있다. 이런 디지털 특성과 생산을 융합한 장치가 3D프린터인데 낮은 생산성과 재료, 물리적 특성의 한계로 산업적 활용이 제한적이다. 특히 3D프린터를 사용하기 위하여 필요한 모델링 소프트웨어 및 프린터 장치에 대한 전문기술로 인하여 사용자 접근성이 떨어지는 등의 개선 점이 있다. 이것을 보완한 3D펜은 휴대성과 사용용이성이 뛰어난 반면 디지털화가 불가능하다는 한계점이 있다. 따라서 디지털화 능력과 사용편이성을 확보하고 프린팅공정 중 유해성 논란이 있는 프린팅 재료의 안전성을 확보하기 위하여 푸드를 결합하여 연구문제와 대안을 도출하였으며 개발한 3D펜을 통하여 디지털화를 실증하였다. 3D펜의 디지털화를 위하여 구조화된 장치를 통하여 아날로그적 3D펜의 움직임을 감지하는 센서를 특정하고 이 움직임을 공간해석 알고리즘을 통하여 3차원 데이터인 X,Y,Z 좌표값으로 변환하였다. 이를 증명하기 위하여 Meshlab v1.3.4을 이용하여 시각화하고 유사성을 확인하였다. 향후 이 장치(푸드펜)을 통하여 청소년 교육 및 시니어헬스케어 프로그램에 활용할 수 있을 것으로 기대한다.

• 세라미스트
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• 제23권2호
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• pp.200-210
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• 2020

Supported catalysts are at the heart of manufacturing essential chemical, agricultural and pharmaceutical products. While the longevity of such systems is critically hinged on the durability of metal nanoparticles, the conventional deposition/dispersion techniques are difficult to enhance the stability of the metal nanoparticles due to the lack of control over the interaction between metal-support. Regarding this matter, ex-solution has begun to be recognized as one of the most promising methodologies to develop thermally and chemically robust nanoparticles. By dissolving desired catalysts as a cation form into a parent oxide, fine and uniformly distributed metal nano-catalysts can be subsequently grown in situ under reductive heat treatment, which is referred to ex-solution. Over the several years, ex-solved analog has resulted in tremendous progress in the chemical-electrochemical applications due to the exceptional robustness coupled with ease synthesis. Herein, we describe the ex-solution process in detail which therein introducing the unique characteristics of ex-solved particles that distinguish them from conventionally dispersed nanoparticles. We then go through the history of science regarding the ex-solution phenomena and summarize several major research achievements which embrace the ex-solved nanoparticles to markedly promote the catalytic performances. In conclusion, we address the remaining challenges and the future perspectives of this rapidly growing field.