• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.969-971
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• 2007

The black/white electronic ink containing high mobility white nano particles and the organic black pigment particles dispersed in dielectric fluid were prepared. A charge control agent affects the electrophoretic zeta potentials of white particle, which show the maximum value in zeta potential. The electronic ink panel fabricated with the charged white particles and the black particles exhibits more than 15:1 contrast ratio at 10V.

• Nuclear Engineering and Technology
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• 제55권3호
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• pp.1061-1070
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• 2023

Over the last few years, lead-free inorganic metal perovskites have gained impressive ground in empowering satellites in space exploration owing to their material stability and performance evolution under extreme space environments. The present work has examined the versatility of eight such perovskites as space radiation shielding materials by computing their photon, charged particles and neutron interaction parameters. Photon interaction parameters were calculated for a wide energy range using PAGEX software. The ranges of heavy charged particles (H, He, C, N, O, Ne, Mg, Si and Fe ions) in these perovskites were estimated using SRIM software in the energy range 1 keV-10 GeV, and that of electrons was computed using ESTAR NIST software in the energy range 0.01 MeV-1 GeV. Further, the macroscopic fast neutron removal cross-sections were also calculated to estimate the neutron shielding efficiencies. The examined shielding parameters of the perovskites varied depending on the radiation type and energy. Among the selected perovskites, Cs₂TiI₆ and Ba₂AgIO₆ displayed superior photon attenuation properties. A 3.5 cm thick Ba₂AgIO₆-based shield could reduce the incident radiation intensity to half its initial value, a thickness even lesser than that of Pb-glass. Besides, CsSnBr₃ and La_0.8Ca_0.2Ni_0.5Ti_0.5O₃ displayed the highest and lowest range values, respectively, for all heavy charged particles. Ba₂AgIO₆ showed electron stopping power (on par with Kovar) better than that of other examined materials. Interestingly, La_0.8Ca_0.2Ni_0.5Ti_0.5O₃ demonstrated neutron removal cross-section values greater than that of standard neutron shielding materials - aluminium and polyethylene. On the whole, the present study not only demonstrates the employment prospects of eco-friendly perovskites for shielding space radiations but also suggests future prospects for research in this direction.

• 한국진공학회지
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• 제10권2호
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• pp.275-281
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• 2001

플라즈마 반응기 내에서 입자 전하 분포가 Gaussian형태로 표현될 때 전하 분포를 가지는 입자들의 충돌에 의한 입자 성장을 discrete-sectional 모델을 사용하여 이론적으로 고찰하였다. 플라즈마 반응기 내에서 입자 성장을 분석하기 위해 monomer크기, monomer생성 속도 등의 공정 변수들을 변화시켰다. 입자 크기가 40 m이상인 큰 입자들은 플라즈마 반응기내에서 대부분이 음으로 존재하였으며 40 m이하인 작은 입자들은 음성, 중성 혹은 양으로 존재하였다 입자 충돌에 의해 입자 크기가 증가함에 따라 입자 표면적의 증가와 더불어 입자가 가지는 평균 음전하수도 증가하였다. 입자 충돌에 의해 큰 입자들이 생성됨에 따라 입자크기분포는 2개의 모드로 양분화 됐다. 본 연구의 이론 결과와 Shiratani 등 [3]의 실험결과가 비교적 잘 맞았으며 본 연구에서 사용한 모델식은 플라즈마 반응기 내에서 수 나노 크기의 입자 성장 연구에도 활용될 수 있을 것으로 기대된다.

• 한국의학물리학회지:의학물리
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• 제8권1호
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• pp.47-52
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• 1997

양성자나 알파입자와 같은 무거운 하전입자가 매질 속을 진행하는 경우에 매질과 상호작용 하여 일어날 수 있는 물리적인 현상을 알아보기 위하여 몬테칼로 기법을 이용하여 시뮬레이션 하였다. 양성자선의 Bragg peak가 에너지의 증가에 따라 물 속에서 깊어짐을 확인하였다. 이러한 Bragg peak 현상을 방사선치료에 이용할 경우에 표적 조직의 흡수선량이 광자와 전자선에 비하여 국소화 되고 주변조직의 보호효과가 탁월함을 알 수 있었다.

• 한국입자에어로졸학회지
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• 제5권2호
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• pp.71-81
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• 2009

In this study, Nylon 6,6 electrospun (ES) nanofiber filter media were prepared at various spinning conditions. The ES filters tested had no intrinsic electrical charges. The ES filters were triboelectrically charged in the course of filter sample handling, and the charge was drastically decayed in a few hours. On the other hand, the corona charged melt blown filter media showed a permanent electrical charge. The electrical charge state of the ES filters was also examined by comparing collection efficiencies of ES filters for uncharged and charged aerosol particles.

• Bulletin of the Korean Chemical Society
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• 제11권6호
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• pp.487-493
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• 1990

A complete potential profile of an electrical double layer is calculated from a distribution function of charged particles based upon a model where the effect of a charged electrode and the finite size of ion are explicitly included. Electrons which are distributed on the electrode surface are assumed not to penetrate the electrode/electrolyte boundary. Formation of the constant density regions and their effects on potential and the electrical double layer capacitances are studied in great detail. The distribution of surface electrons as well as the constant density regions are found to be essential in characterizing the electrical double layer. The introduction of the ion size into the prior electrical double layer model of an ideally polarizable electrode/point charged electrolyte system, shows a great improvement in its characteristics mostly at negative potential region.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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• pp.297-300
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• 2006

This article discusses about the droplet movement on the super-hydrophobic surface by the electro-wetting on dielectric and the effect of particles on the contact angle as well as the movement is investigated. The movement of droplet, driven by the principle of electro-wetting on dielectric, and the effect of particles are experimentally verified according to the driving voltage and different particles concentrations (fluorescent, charged particles). To increase the contact angle, the super-hydrophobic surface is fabricated and applied to the dielectric layer for the EWOD device. Then its performance is verified and discussed.

• 대한기계학회논문집B
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• 제24권3호
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• pp.477-484
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• 2000

Microcontamination caused by particle deposition on the head disk interface threatens the reliability of hard disk drive. Design of slider rail to control contamination becomes an important issue in magnetic recording. In this paper, how particles adhere to the slider and the disk is examined. To investigate accumulation mechanism of the particles, trajectory of the particles in a slider/disk interface is simulated with considering various forces including drag force, gravitational force, Saffman lift force, and electrostatic force. It is found that the charged particles can easily adhere to the slider or disk surface, if an electric field exists between the slider and the disk. It is supposed that the vertical motion of the particles should be related with not only Saffman force but also electrostatic force.

• 대한기계학회논문집B
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• 제27권6호
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• pp.677-684
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• 2003

A new unipolar aerosol charger was developed by using an indirect photoelectric charging. The charger consists of two coaxial tubes, the inner UV lamp wrapped with stainless mesh and the outer Al cylinder. In this study, the effects of flow rate, particle size, and electric field were examined to search the optimal charging conditions with experimental and numerical methods. Monodisperse NaCl particles were fed into an annular space and the particles were charged by negative ions generated from Al plate exposed to the UV light. According to experimental results, the average number of elementary charge on particles increases from 2.5 to 5.5 as particle size increases from 50nm to 130nm at 2.5 L/min and 100V. The average number of elementary charge on particles was maximized at 25V as the electric potential between the stainless mesh and Al plate was varied from 0V to 400V.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.1211-1212
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• 2006

The electrophoretic deposition process of Ni nano-particles was employed for self-repairing of heat exchanger tubes. For electrophoretic deposition of Ni nano-particles on pitted Ni alloy specimen, a constant electric field of 100 V $cm^{-1}$ was applied to the specimen for 180 s in Ni-dispersed solution. It was found that as electrophoretic deposition proceeded, the size of the pit remarkably decreased due to the agglomeration of Ni nano-particles at the pit. This strongly suggests that the electrophoretic mobility of the charged particles is larger for the pit with a higher current value rather than outer surfaces with a lower current value.