• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.552-552
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• 2012

We fabricated reduced graphene oxide field-effect transistor (RGO-FET) on glass for highly sensitive temperature and IR detection. The device has the channels of RGO responsive to physical stimuli such as temperature and IR. The RGO sensing layers are fabricated from exfoliated graphene oxide sheets that are deposited to form a thin continuous network by electrostatic assembly. These graphene oxide networks are reduced toward reduce graphene oxide by exposure to a hydrazine hydrate vapor. To improve performance and eliminate interferences from oxygen and water vapor absorption to electrical properties of RGO-FET, the sensor devices were encapsulated by the tetratetracontane layer after annealing treatment. The device with encapsulation layer showed lower hysteresis, improved stability, and better repeatability. The temperature response of RGO-FET is examined by measuring changing the temperature, the device exhibited the high sensitivity and repeatability even with the temperature interval of 1 K. We also demonstrated that our devices have capability of IR sensing.

• 한국입자에어로졸학회지
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• 제5권3호
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• pp.123-131
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• 2009

This paper presents simulation results of particle transport in low-pressure, low-temperature plasma environment. The size dependent transport of particles in the plasma is investigated with a two-dimensional simulation tool developed in-house for plasma chamber analysis and design. The plasma model consists of the first two and three moments of the Boltzmann equation for ion and electron fluids respectively, coupled to Poisson's equation for the self-consistent electric field. The particle transport model takes into account all important factors, such as gravitational, electrostatic, ion drag, neutral drag and Brownian forces, affecting the motion of particles in the plasma environment. The particle transport model coupled with both neutral fluid and plasma models is simulated through a Lagrangian approach tracking the individual trajectory of each particle by taking a force balance on the particle. The size dependant trap locations of particles ranging from a few nm to a few ${\mu}m$ are identified in both electropositive and electronegative plasmas. The simulation results show that particles are trapped at locations where the forces acting on them balance. While fine particles tend to be trapped in the bulk, large particles accumulate near bottom sheath boundaries and around material interfaces, such as wafer and electrode edges where a sudden change in electric field occurs. Overall, small particles form a "dome" shape around the center of the plasma reactor and are also trapped in a "ring" near the radial sheath boundaries, while larger particles accumulate only in the "ring". These simulation results are qualitatively in good agreement with experimental observation.

• JSTS:Journal of Semiconductor Technology and Science
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• 제11권4호
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• pp.278-286
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• 2011

In this paper, we present a compact model of gate-voltage-dependent quantum effects in short-channel surrounding-gate (SG) metal-oxide-semiconductor field-effect transistors (MOSFETs). We based the model on a two-dimensional (2-D) analytical solution of Poisson's equation using cylindrical coordinates. We used the model to investigate the electrostatic potential and current sensitivities of various gate lengths ($L_g$) and radii (R). Schr$\ddot{o}$dinger's equation was solved analytically for a one-dimensional (1-D) quantum well to include quantum effects in the model. The model takes into account quantum effects in the inversion region of the SG MOSFET using a triangular well. We show that the new model is in excellent agreement with the device simulation results in all regions of operation.

• 한국광학회지
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• 제19권5호
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• pp.365-369
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• 2008

정전기장 편향기를 사용하는 저전압 초소형 전자칼럼에서 전자빔 집속 적정조건에 대해 조사하였다. 일정한 전자 방출 팁 전압조건에서 소스렌즈를 이용하여 전자빔을 집속할 경우 아인젤 렌즈를 이용할 경우보다 주사면적은 컸으나 전류영상의 선명도는 낮게 측정되었다. 3차원 전산시늉 결과 소스렌즈를 사용하여 전자빔을 집속할 경우 전자빔의 초점크기와 편향이 아인젤 렌즈를 이용하여 집속할 경우보다 큰 것으로 조사되었다.

• Bulletin of the Korean Chemical Society
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• 제30권11호
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• pp.2617-2620
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• 2009

Using Coulomb-Yukawa like correlated interaction potentials of integer and noninteger indices the series expansion formulae in terms of multicenter overlap integrals of three complete orthonormal sets of ${\psi}^{\alpha}$‒exponential type orbitals and linear combination coefficients of molecular orbitals are established for the potential of electrostatic field produced by the charges of molecule, where $\alpha$ = 1, 0, ‒1, ‒2,${\cdots}$. The formulae obtained can be useful for the study of interaction between atomic--molecular systems containing any number of closed and open shells when the ${\psi}^{\alpha}$‒exponential type basis functions and Coulomb-Yukawa like correlated interaction potentials are used in the Hartree-Fock-Roothaan and explicitly correlated approximations. The final results are valid for the arbitrary values of parameters of correlated interaction potentials and orbitals. As an example of application, the calculations have been performed for the potential energy of interaction between electron and molecule $H_2O$ using combined Hartree-Fock-Roothaan equations suggested by the author.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 C
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• pp.1620-1622
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• 2003

Recently, as the technology for the development of high voltage power apparatus using SF6 gas has made remarkable progress, it became possible to develop more compact power apparatus adopting single body substation system. In these gas insulated power apparatus, it is impossible to achieve perfect and safe insulation using only SF6 gas, because some solid insulation parts should be installed to support current-carrying conductor parts for electrical and mechanical safety. When spacers were installed in SF6 gas insulation system, they were exposed to severe electrical intensification which could reduce system insulation performance and restrict the rated operating voltage So, it is necessary to clarify the dielectric characteristics of spacers by analytically and experimentally, in order to design and develop more compact and optimum gas insulated systems. In this paper, the field distribution of three-phase spacers were investigated using three dimensional electrostatic field analysis tool adopting BEM method. And the obtained results were compared to the conventional two dimensional computations. According to these three dimensional calculations, it was possible to find out weak points in the spacer more clearly and these results could be applied to design more compact and optimum three phase spacer developments.

• Korean Chemical Engineering Research
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• 제62권3호
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• pp.269-273
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• 2024

TiO₂ 전기유변 유체의 수직 응력을 실험적으로 측정하고 전산모사도 수행하였다. 전기장 하에서 수직 응력은 입자 사이의 수직 방향의 정전기 인력에 의해 음수 값을 보였고, 수직 응력의 절대값은 전기장의 증가에 따라 급격하게 상승하였다. 전단 응력에서처럼 수직 항복 응력도 E²에 비례하는 특성을 보여, 수직 응력을 전기유변 현상의 평가에 활용할 수 있음을 나타냈다. 수직 응력의 거동을 이해하기 위해 수행한 전산모사는 수직 응력이 실험 결과와 정성적으로 잘 일치함을 보여 주었다. 또한 전기장 하에서는 전단 속도가 증가함에 따라 수직 응력의 절대값이 줄어드는 경향은 전단 속도에 따른 입자들의 구조 변화로 발생하는 것으로 나타났다.

• 대한환경공학회지
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• 제27권4호
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• pp.445-449
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• 2005

본 연구의 목적은 실제 가동 장치에 연결된 전기집진장치의 제거효율을 향상시키기 위하여 주입되는 트리에틸아민 주입 조건에 대한 실제 장치의 효능을 평가하는 것이다. 국내 발전소에서는 주로 호주, 중국, 남아프리카 및 미국에서 수입되는 비스무스 석탄을 이용하는데 비록 이러한 수입 석탄의 종류에 따라 발생되는 비산재의 전기저항도값이 다소 차이가 있지만, 석탄 연소시 배출되는 비산재의 대표적인 전기저항도값은 $1{\times}10^{12}\;{\Omega}-cm$ 큰 것으로 나타났다. 이 때문에 국내 대부분의 적기집진기 가동시 백 코로나 문제가 빈번하게 나타난 것으로 확인되었다. 전기집진장치 출구에서 직접 측정된 분진의 농도, 매연도 및 분진의 전기저항도와 집진효율을 동시에 확인한 결과에 따르면, 트리메틸아민의 주입이 전기집진장치의 집진효율을 상당량 증가시키는 것으로 확인되었다. 트리에틸아민 주입 전에 비산재의 전기저항도값이 $1.9{\times}10^{12}\;{\Omega}-cm$이던 것이 15 ppm(순도 99.7%) 주입시 비산재의 전기저항도값이 $2.1{\times}10^{11}\;{\Omega}-cm$으로 감소하였다. 이러한 조건에서 연돌에서 배출되는 분진의 배출량은 대략 80% 정도 감소율을 나타내며 농도 대비 $70\;mg/Sm^3$ to $14\;mg/Sm^3$수준이었다.

• 대한화학회지
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• 제56권2호
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• pp.195-200
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• 2012

In this study we present a new approach for computing the partial atomic charge derived from the wavefunctions of molecules. This charge, which we call the "y_charge", was calculated by taking into account the energy level and orbital populations in each molecular orbital (MO). The charge calculations were performed in the software, which was developed by us, developed using the C# programming language. Partial atomic charges cannot be calculated directly from quantum mechanics. According to a partitioning function, the electron density of constituent molecular atoms depends on the electrostatic attraction field of the nucleus. Taking into account the Boltzmann population of each MO as a function of its energy and temperature we obtain a formula of partial charges.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 학술대회지
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• pp.455-459
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• 2004

Electrostatic discharge(ESD) is a serious reliability concern. It causes approximately most of all field failures of integrated circuits. Inevitably, future IC technologies will shrink the dimensions of interconnects, gate oxides, and junction depths, causing ICs to be increasingly susceptible to ESD-induced damage [1][2][3]. This thesis shows the optimization of the ESD protection circuit based on the tested results of MM (Machine Model) and HBM (Human Body Model), regardless of existing Reference in fully silicided 0.18 um CMOS process. His thesis found that, by the formation of silicide in a source and drain contact, the dimensions around the contact had a less influence on the ESD robustness and the channel width had a large influence on the ESD robustness [8].