• Title/Summary/Keyword: Particle beam

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Influence of Image Sticking on Electra-Optical Characteristics in Alternating-Current Plasma Display Panels

  • Choi, J.H.;Jung, Y.;Jung, K.B.;Kim, S.B.;Choi, E.H.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2003.07a
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    • pp.760-763
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    • 2003
  • We have investigated the electro-optical characteristics of image sticking in AC PDP. Although Image sticking is one of major factors to determine display quality in AC PDP, so far, it has not being reported why it is occurred and how we can prevent it. In this experiment, we have analyzed the effect of MgO protective layer and phosphor on the image sticking and we have measured the difference of firing voltage, brightness and discharge current between sticking image and normal image in AC PDP. As a result, Phosphor degradation is a more major factor than MgO protective layer and the firing voltage of gas discharge in sticking image is higher than that of normal discharge.

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Influence of wall charge configurations prior to addressing discharge on dynamic margin in AC Plasma Display Panel

  • Jung, Y.;Choi, J.H.;Jung, K.B.;Kim, S.B.;Choi, E.H.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2003.07a
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    • pp.764-767
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    • 2003
  • We have experimentally investigated the influence of wall charge configurations prior to addressing discharge on dynamic margin in AC plasma display panel. In this experiment, we have analyzed the quantity and polarity of wall charge accumulated on the front and rear dielectrics just prior to the addressing discharge under the conventional driving sequence.

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Electro-Optical characteristics with dielectric thickness of AC-PDP

  • Jung, K.B.;Choi, J.H.;Kim, S.B.;Jung, Y.;Choi, E.H.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2003.07a
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    • pp.768-770
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    • 2003
  • In AC PDP, since charges generated by gas discharge are accumulated on the dielectric. The dielectric is a major factor to determine cell capacitance and its memory effect is a play an important role in PDP driving. In this experiment, we have investigated the electro-optical characteristics with dielectric thickness and we have analyzed wall charge and wall voltage by Q-V energy diagram. The dielectric thickness was varied from 20 um to 50 um. As results, according to the dielectric thickness increase,cell capacitance and power consumption is reduced.

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Measurement of Electron Temperature and Plasma Density in Coplanar AC Plasma Display Panels.

  • Cho, Il-Ryong;Moon, Min-Yook;Ryu, Chung-Gon;Choi, Myung-Chul;Choi, Eun-Ha
    • 한국정보디스플레이학회:학술대회논문집
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    • 2003.07a
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    • pp.748-751
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    • 2003
  • The electron temperature and plasma density in coplanar alternating-current plasma display panels (AC-PDPs) have been experimentally investigated by a micro Langmuir probe and the high speed discharge images in this experiment.

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Profile and Dose Distribution for Therapeutic Heavy Ion Beams

  • Sasaki, Hitomi;Komori, Masataka;Kohno, Toshiyuki;Kanai, Tatsuaki;Hirai, Masaaki;Urakabe, Eriko;Nishio, Teiji
    • Proceedings of the Korean Society of Medical Physics Conference
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    • 2002.09a
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    • pp.211-213
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    • 2002
  • The purpose of this work is acquiring some parameters of therapeutic heavy ion beams after penetrating a thick target. The experiments were performed using a pencil-like $\^$12/C beam of about 3 mm in diameter from NIRS-HIMAC, and the data were taken at several points of the target thickness for $\^$12/C beam of 290 MeV/u and 400 MeV/u. By the simultaneous measurements using some detectors, the atomic number of each fragment particle was identified, and the beam profile, the dose distribution and the LET spectrum for each element were derived.

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ELECTRON TEMPERATURE ESTIMATION OF NON-THERMAL ATMOSPHERIC-PRESSURE NEON AND OXYGEN ADMIXTURE PLASMA JET BY CONVECTIVE WAVE PACKET MODEL

  • SORNSAKDANUPHAP, Jirapong;SUANPOOT, Pradoong;Hong, Young June;Ghimire, Bhagirath;CHO, Guangsup;CHOI, EunHa
    • Proceedings of the Korean Vacuum Society Conference
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    • 2016.02a
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    • pp.207-207
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    • 2016
  • plasma group velocities of neon with oxygen admixture (ug) are obtained by intensified charge coupled device (ICCD) camera images at fixed gate width time of 5 ns. The propagation velocities outside interelectrode region are in the order of 104 m/s.The plasma ambipolar diffusion velocities are calculated to be in the order of 102 m/s. Plasma jet is generated by all fixed sinusoidal power supply, total gas flow and repetition frequency at 3 kV, 800 sccm and 40 kHz, respectively. The amount of oxygen admixture is varied from 0 to 2.75 %. By employing one dimensional convective wave packet model, the electron temperatures in non-thermal atmospheric-pressure plasma jet are estimated to be in a range from 1.65 to 1.95 eV.

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ELECTRON TEMPERATURE ESTIMATION OF NON-THERMAL ATMOSPHERIC-PRESSURE NEON AND ARGON PLASMA JET BY CONVECTIVE WAVE PACKET MODEL

  • SORNSAKDANUPHAP, Jirapong;SUANPOOT, Pradoong;Hong, Young June;Ghimire, Bhagirath;CHO, Guangsup;CHOI, Eun Ha
    • Proceedings of the Korean Vacuum Society Conference
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    • 2015.08a
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    • pp.156.1-156.1
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    • 2015
  • Neon and argon plasma group velocities (ug) are obtained by intensified charge coupled device (ICCD) camera images at fixed gate width time of 5 ns. The propagation velocities in upstream and downstream region are in the order of 104-105 m/s. The plasma ambipolar diffusion velocities are calculated to be in the order of 101-102 m/s. Plasma jet is generated by sinusoidal power supply in varying voltages from 1 to 4 kV at repetition frequency of 40 kHz. By employing one dimensional convective wave packet model, the neon and argon electron temperatures in non-thermal atmospheric-pressure plasma jet are estimated to be 1.95 and 1.18 eV, respectively.

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Measurement of excited Xe($1s_4$) and Xe($1S_5$) atoms by laser absorption spectroscopy in coplanar AC-PDP

  • Oh, P.Y.;Lee, J.H.;Moon, H.S.;Hong, J.W.;Jeon, W.;Cho, G.S.;Choi, E.H.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2004.08a
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    • pp.515-517
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    • 2004
  • The laser absorption spectroscopy has been used for measuresurement of the xenon atoms in the resonant $1S_4$ and metastable $1S_5$ states in coplanar AC PDP. For the purpose of improving VUV luminous efficiency and optimization of PDP cells, it is important to study behavior of excited Xe atoms in a micro-discharge cell of a coplanar AC-PDP. We measured the xenon excited density of $1S_5$ and $1S_4$ state under mixture gas of Ne-Xe(10%) with gas pressure of 350 Torr and sustaining gap distance of 150 um.

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Basics of particle therapy II: relative biological effectiveness

  • Choi, Jin-Hyun;Kang, Jin-Oh
    • Radiation Oncology Journal
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    • v.30 no.1
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    • pp.1-13
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    • 2012
  • In the previous review, the physical aspect of heavy particles, with a focus on the carbon beam was introduced. Particle beam therapy has many potential advantages for cancer treatment without increasing severe side effects in normal tissue, these kinds of radiation have different biologic characteristics and have advantages over using conventional photon beam radiation during treatment. The relative biological effectiveness (RBE) is used for many biological, clinical endpoints among different radiation types and is the only convenient way to transfer the clinical experience in radiotherapy with photons to another type of radiation therapy. However, the RBE varies dependent on the energy of the beam, the fractionation, cell types, oxygenation status, and the biological endpoint studied. Thus this review describes the concerns about RBE related to particle beam to increase interests of the Korean radiation oncologists' society.