• Transactions on Electrical and Electronic Materials
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• 제13권5호
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• pp.233-236
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• 2012

The driving properties of a particle-insertion method that filters non-moving particles are analyzed, by measuring its optical and electrical properties. An area that is occupied by the moved particles is proposed, as a desirable evaluation method for a reflective display. To compare the driving property of the particle-moving method with that of the reported simple particle-loading method, two panels are fabricated, according to the different particle-insertion methods, in the same panel condition, of which the width of ribs is $30{\mu}m$, the cell size is $220{\mu}m{\times}220{\mu}m$, the cell gap is $116-120{\mu}m$, the q/m value of the black particles is $+1.8{\mu}C/g$ and that for the white particles is $-4.3{\mu}C/g$. The particle-moving method has a filtering effect which excludes the non-moving particles, inserting only movable particles into the respective cell, so that a panel fabricated by the particle-moving method can drive most of the particles in a cell. Also, most of the particles move at the threshold voltage of 40 V, with enhanced reflectivity. The driving property is also verified by measurement of the occupation rate of the moved particles.

• 한국항공우주학회지
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• 제45권11호
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• pp.932-938
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• 2017

플라자마의 거동을 오일러리안 격자와 라그랑지안 입자를 혼합하여 해석하는 Particle-in-cell 기법을 적용하여 간략화된 홀추력기를 해석하였다. 본 연구는 중성입자, 이온입자 뿐만 아니라 전자도 라그랑지안 기법으로 개별추적 계산하기 때문에 message passing interface 기법을 이용해 대용량 계산이 가능한 병렬클러스터링을 적용하였다. 계산에 앞서 일정한 벡터의 자기장에서 전자군의 나선형 거동을 해석하였고, 절대해와 일치함을 확인하여 코드를 검증하였다. 실린더 내부에 반경방향으로 일정한 자기장과 축방향으로 일정한 전기장을 고정시켜 플라즈마의 거동을 PIC 모델을 이용하여 해석하였다. 반응 실린더 내부에 전자가 로렌츠 힘에 의해 이중나선을 그리며 구속되는 현상이 잘 포착되었고, 고속 회전하는 전자와 주입된 중성입자가 충돌하여 이온화 되었고, 대전된 입자가 축방향의 전기장에 의해 급 가속하는 현상 또한 잘 모사되어 플라즈마의 플룸 거동을 모사하였다.

• 대한의용생체공학회:의공학회지
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• 제43권2호
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• pp.94-101
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• 2022

Recent advancement of micro/nano technology enables the development of diverse micro/nano particle-based delivery systems. Due to the multi-functionality and engineerability, particle-based delivery system are expected to be a promising method for delivery to the target cell. Since the particle-based delivery system should be delivered to the various kinds of target cell, including the cardiovascular system, cancer cell etc., it is frequently decorated with multiple kinds of targeting molecule(s) to induce specific interaction to the target cell. The surface decorated molecules interact with the cell surface expressed molecule(s) to specifically form a firm adhesion. Thus, in this study, the probability of adhesion is estimated to predict the possibility to form a firm adhesion for the multi-ligand decorated particle-based delivery system.

• 전기학회논문지
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• 제59권12호
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• pp.2250-2255
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• 2010

An fine silver particle has a variety of uses, such as in killing micrograms and as catalysts. Many techniques have been used for the production of the fine particles. Faraday cell, consisting of two silver electrodes in an electrolyte, is unique, but it is hard to get a very fine particle by this method. A finer silver nano-particle producing cell, utilizing a dielectric bed as a lower electric current and higher field controlling means, has been proposed and investigated. The I-V characteristics of the cell and effect of the dielectric bed on the producing finer silver nano-particles have been investigated. The I-V characteristics of the cell with the dielectric bed were different from that of the same system without the bed, due to the increased cell resistance and elevated electric field intensity. It is found that the proposed cell with the dielectric bed can produce finer silver nano-particles effectively, which, however, can be used as one of effective fine silver nano-particle producing means.

• 한국전기전자재료학회논문지
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• 제22권1호
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• pp.93-97
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• 2009

We analyzed voltage characteristics of toner particle type display according to particle layers and cell gap between two electrodes and ascertained the aging effects by measuring the response time of particles with and without aging process. The threshold/driving/breakdown voltage is proportional to layers of toner particles and cell gap and the response time at driving voltage is faster than that of threshold and breakdown voltage because of different q/m of color and black particles. The analysis of response time is a method of estimation of optical characteristics, driving voltage and particle lumping and these results are promoted by aging process. We use the laser and photodiode to measure response time and optical properties. It has not been studied and reported to analyze the relationship of response time, threshold/driving/breakdown voltage, lumping phenomena, cell gap, and aging process for toner particle type display.

• 한국산학기술학회논문지
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• 제9권1호
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• pp.35-40
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• 2008

본 논문에서 대전입자형 디스플레이 패널의 기본적인 구동방식 및 각각의 셀의 선택적 구동방식에 관하여 기술하였다. 패널을 제작하기 위해 $500{\mu}m{\times}500{\mu}m$의 셀면적을 가지고 있는 마스크패턴을 설계하였으며 기본적인 구동조건을 바탕으로 셀갭의 변화에 따른 구동전압의 변화를 관찰하였다. 수동메트릭스 방식으로 구동되는 패널의 각각의 셀을 선택적으로 구동하기 위해 선택된 셀과 선택되지 않은 셀의 전위차 상관관계를 확립하여 패널의 선택적인 구동을 수행하였으며 구동이 완료된 패널의 crosstalk현상을 관찰하였다. 또한 추가적인 전압을 인가하지 않아도 마지막 이미지가 오랜 시간 동안 유지되는 패널의 메모리 효과를 확인하였다.

• 대한기계학회논문집
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• 제18권2호
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• pp.432-445
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• 1994

From a theoretical analysis point of view, the 2-stage precipitator is decomposed into two units: charging cell and collecting cell. Collection efficiency predictions of the two-stage parallel-plate electrostatic precipitator have been performed theoretically incorporating with the charging and the collecting cells. Particle trajectorise passing the charging cell have been modeled as a simple one. Particle charge distribution at the outlet of the charging cell is calculated through integration of the present unipolar combined charging rate along the entire particle trajectory, and average charge of particles at the outlet of the charging cell is obtained from the particle charge distribution. As for the collecting cell, the diminution of particle concentration along the longitudinal direction of the collecting cell is investigated considering the conventional Deutsch's theory and the laminar theory. One should note that the collection efficiency formula derived is based on monodisperse aerosols. It has been confirmed through the analysis that predictions of particle charge by applying White's unipolar diffusion charging theory overpredict actual cases in the continuum regime, while predictions by Fuch's unipolar diffusion charging theory indicate the reasonable result in the same regime. Theoretical predictions of collection efficiency are also compared with the available experimental results. Comparisons show that the experimental results are consistently located in the collection efficiency region bounded by the two limits, the Deutsch and the laminar collection efficiencies. Finally design parameters of the 2-stage electrostatic precipitator have been investigated systematically through the one-variable-at-a-time method in terms of collection efficiency. Applied voltages on the corona wire of the charging cell and the plate of the collecting cell, and the average air velocity have been selected as the design parameters.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.53-54
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• 2007

Charged particle type display using particles which have opposite charge and color is based on effect of reversible optical property due to electric field. we designed mask pattern for fabrication of the charged particle type display based on glass substrate and investigated cell gap dependent of driving voltage and selectively driving method. the panel driven by our selectively driving method, we could obtain image which had vary little crosstalk caused by electrical interference and conform the last image maintained by memory effect without additional voltage.

• International Journal of Naval Architecture and Ocean Engineering
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• 제7권6호
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• pp.1034-1043
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• 2015

This is the continuation of a numerical study on vortex shedding from a blunt trailing-edge of a hydrofoil. In our previous work (Lee et al., 2015), numerical schemes for efficient computations were successfully implemented; i.e. multiple domains, the approximation of domain boundary conditions using cubic spline functions, and particle-based domain decomposition for better load balancing. In this study, numerical results through a hybrid particle-mesh method which adopts the Vortex-In-Cell (VIC) method and the Brinkman penalization model are further rigorously validated through comparison to experimental data at the Reynolds number of $2{\times}10^6$. The effects of changes in numerical parameters are also explored herein. We find that the present numerical method enables us to reasonably simulate vortex shedding phenomenon, as well as turbulent wakes of a hydrofoil.

• 한국가시화정보학회지
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• 제16권2호
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• pp.23-30
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• 2018

The present study compares flow fields reconstructed by data assimilation method with different combinations of parameters. As a data assimilation method, Vortex-in-Cell-sharp (VIC#), which supplements additional constraints and multigrid approximation to Vortex-in-Cell-plus (VIC+), is used to reconstruct flow fields from scattered particle tracks. Two parameters, standard deviation of Gaussian radial basis function (RBF) and grid spacing, are mainly tested using artificial data sets which contain few particle tracks. Consequent flow fields are analyzed in terms of flow structure sizes. It is demonstrated that sizes of the flow structures are proportional to an actual scale of the standard deviation of RBF. It implies that a combination of larger grid spacing and smaller standard deviation which preserves the actual standard deviation is able to save computational resources in case of a low track density. In addition, a simple comparison using an experimental data filled with dense particle tracks is conducted.