• 폴리머
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• 제37권2호
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• pp.162-166
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• 2013

고분자 입자에 그래핀이 코팅된 복합체를 제조하고 구조 및 형태변화를 통한 그래핀의 새로운 응용 가능성이 제기되고 있다. 그래핀이 표면에 흡착된 폴리스티렌 복합입자의 물성제어를 위해서, 물 분산매 하에 혼합방법과 혼합순서를 달리하여 흡착반응 시간과 혼합물 내의 순간적인 상대농도 차이를 조사하였다. 유화중합으로 중합된 폴리스티렌 입자에 폴리에틸렌이민을 흡착시켜 표면에 양전하를 갖게 만든 고분자 입자와, 흑연의 화학적 박리법으로 표면에 음전하를 갖도록 제조된 그래핀 산화물과의 서로 반대되는 전하를 갖는 두 입자의 흡착을 유도한 결과 흡착반응 시간이 길수록, 순간 상대 농도차가 클수록 균질하게 표면 코팅이 만들어지고, 응집이 적은 복합 입자를 제조할 수 있었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1519_1520
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• 2009

This paper investigates forces on a charged particle used in the e-paper application. The particles were inserted into the pixels and according to the applied voltage, particles moves up or down to the electrodes. So, to design the e-paper, the force analysis is very important for the stable operation of e-paper. For these purposes, we divided forces into 4 different forces and numerically evaluated each force. From the simulation results, we confirmed that the minimum voltage to detach the particle from the bottom electrode can be obtained for the given condition.

• International Journal of Aeronautical and Space Sciences
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• 제3권2호
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• pp.40-45
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• 2002

A radiation analysis is performed for the Ka and Ku-band transponder of the Communications and Broadcasting Satellite (CBS) that is planned for launch into the geo-synchronous orbit. A particular attention is given to calculation of Total Ionizing Dose (TID) for the mission life time of 15 + 3 years. A numerical modeling of the charged particles at the geo-synchronous orbit is undertaken. The charged particles from the modeling are then transported through the mechanical structure and component housings of the transponder. A set of locations are selected for the detailed calculation of TID. The results from the present calculation show that three-dimensional modeling of the component housings as well as the mechanical structure of the spacecraft is requisite in order to acquire a reliable calculation of TID.

• Radiation Oncology Journal
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• 제29권3호
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• pp.135-146
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• 2011

With the advance of modern radiation therapy technique, radiation dose conformation and dose distribution have improved dramatically. However, the progress does not completely fulfi ll the goal of cancer treatment such as improved local control or survival. The discordances with the clinical results are from the biophysical nature of photon, which is the main source of radiation therapy in current field, with the lower linear energy transfer to the target. As part of a natural progression, there recently has been a resurgence of interest in particle therapy, specifically using heavy charged particles, because these kinds of radiations serve theoretical advantages in both biological and physical aspects. The Korean government is to set up a heavy charged particle facility in Korea Institute of Radiological & Medical Sciences. This review introduces some of the elementary physics of the various particles for the sake of Korean radiation oncologists' interest.

• Journal of Information Display
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• 제6권3호
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• pp.30-35
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• 2005

We have developed a paper-like display using polymer particles charged triboelectrically. By using a toner-type display with a simple structure, we continued that polymer particle movement is controlled by only a voltage difference between scan and data electrode. We fabricated a diagonal 2.4 inch panel on the glass substrate and successfully produced an image by the passive driving method with operating voltages of about ${\pm}$ 120 V. The contrast ratio was 4:1.

• 한국전기전자재료학회논문지
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• 제24권11호
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• pp.915-919
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• 2011

We analyzed various forces affective to the charged particles in closed space, to explain the image degradation and lifetime-shortening phenomena because of particle lumping which is one of the serious problems in reflective displays. It is possible to predict the quantity of q/m which is the most important parameter in determining the optical and electrical characteristics, by calculating the image force and kinetic energy. For stable driving, the quantity of q/m must be in the defined range but it changes during the fabrication process, so we added the filtering process to solve this problem and obtained the well-defined nonlinear driving voltage coinciding with the threshold voltage. And we obtained the fully-driving property which prevents the particle lumping and decides the image quality and lifetime of panel from the optical characteristics and occupation surface of moving particles.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 정기총회 및 추계학술대회 논문집 학회본부
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• pp.228-230
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• 1993

In this paper, to investigate the activation energy, dipole moment, relaxation time, and so on related to charged particles more completely, it was applied numerical method of asymptotic estimation to separate single relaxation from TSC spectra with a complex relaxation. As a result, we could calculated the error of physical factors related to charged particles of specimen, more accurately.

• 태양에너지
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• 제9권2호
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• pp.58-68
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• 1989

This paper describes an experimental study that was performed to determine the limiting factors on the power output in the closed cycle Electro-Hydro-Dynamic generator of small capacity. A corona discharge for producing unipolar charged particles used as the charging method. The experiment demonstrated that the corona method of charging was an efficient and effective means of producing unipolar charged particles. Four factors having an effect on the power output characteristics of EHD generator are discussed and examined experimentally, using methyl alcohol and kerosene as working fluides; a. The conversion length between attractor and collector. b. The corona current of Emitter. c. The flow velocity of working fluids. d. Load resistance. This results are as follows; 1) There in a critical value in conversion length for its maximum power output. 2) Power output increases almost linearly with corona current and flow velocity. 3) There is the critical value of load resistance producing a maximum power output. 4) Kerosene is known better working fluid than Methyl alcohol in this EHD generator.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.930-933
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• 2000

To understand the behavior of electron, ions and radicals on radio-frequency non-equilibrium plasma, it is necessary to know the basic information about its fundamental properties and reactions. Especially, the transient response of radio-frequency plasma has an important means of controlling selective etch rates and investigating the stability of a plasma chemical process. In this paper, we present the results of periodic steady-state behavior and transient behavior carbon Tetrafluoride(CF$_4$) discharge at 0.2 Torr in a 2 cm gap parallel-plate. After the number densities of charged particles became steady-state, the applied voltage was increased or decreased in an instant and the transient behavior of charged particles and radicals was investigated from one steady-state to the next steady state.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 1999년도 추계학술대회 논문집
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• pp.465-466
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• 1999

섬유층 여과기(fibrous filter)는 일반적으로 공기여과기(air filter) 라고 불리는 여과기로 fiber의 직경, filter의 두께, 공극률, 하전 여부에 따라 그 용도가 다양하다. 전하를 가진 섬유로 제조한 정전 필터는 장시간 사용시에 일반 섬유층 필터에 비해 작은 압력강하와 높은 집진 효율을 나타내기 때문에 성능과 수명이 증가한다.(중략)