• Title/Summary/Keyword: electron impact

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SPECTRAL DIAGNOSTICS OF THE ENERGETIC PARTICLES IN SOLAR FLARES

  • FANG C.;DING M. D.;HENOUX J. C.;GAN W. Q.
    • Journal of The Korean Astronomical Society
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    • v.29 no.spc1
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    • pp.295-298
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    • 1996
  • Non-LTE calculations, with the non-thermal ionization effects included, indicated that for electron bombardment, the H$\alpha$ line is widely broadened and shows a strong central reversal. Significant enhancements at the line wings of Ly$\alpha$ and Ly$\beta$ are also predicted at the beginning of the impulsive phase of flares. For the proton bombardment, no strong broadening and no large central reversal are expected. However, due to proton-hydrogen charge exchange, the enhancements at the red wings of Ly$\alpha$ and Ly$\beta$ lines at the early impulsive phase of flares are significant. Our results show that the electron beam can also in some cases generate visible and UV continuum emission in white-light flares. However, at the onset phase, a negative flare may appear within several seconds, due to the increase of the H- opacity. Another spectroscopic signature of energetic particles, i.e. the impact polarization of atomic lines, is also mentioned.

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Effect of Welding Variables for EBW Process in AISI 4130 by Taguchi Method (다구찌 방법을 이용한 AISI 4130재료에서 EBW공정의 용접 변수 영향)

  • Kim, Won-Hoon
    • Journal of Welding and Joining
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    • v.15 no.6
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    • pp.66-77
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    • 1997
  • In the present work, Taguchi method for electron beam welding(EBW) process in AISI 4130 steel plate has been adopted for investigating the contribution of effect of welding variables. $A L_8(2^7)$ orthogonal array is adopted to obtain the effect of adjustment parameters. The adjustment parameters consist of accelerating voltage, beam current, travel speed and focus currrent. And the quality features selected for the EBW process are bead width of weldment, reinforcement, penetration depth, undercut and area of weld metal. Variance analysis is performed in order to check the effect of adjustment parameters on EBW. The mechanical properties of electron beam welded joints for each heat treatment conditions are investigated in comparison with those of base metal, especially from the view point of tensile and impact properties.

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Numerical Modeling of an Inductively Coupled Plasma Sputter Sublimation Deposition System

  • Joo, Junghoon
    • Applied Science and Convergence Technology
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    • v.23 no.4
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    • pp.179-186
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    • 2014
  • Fluid model based numerical simulation was carried out for an inductively coupled plasma assisted sputter deposition system. Power absorption, electron temperature and density distribution was modeled with drift diffusion approximation. Effect of an electrically conducting substrate was analyzed and showed confined plasma below the substrate. Part of the plasma was leaked around the substrate edge. Comparison between the quasi-neutrality based compact model and Poisson equation resolved model showed more broadened profile in inductively coupled plasma power absorption than quasi-neutrality case, but very similar Ar ion number density profile. Electric potential was calculated to be in the range of 50 V between a Cr rod source and a conductive substrate. A new model including Cr sputtering by Ar+was developed and used in simulating Cr deposition process. Cr was modeled to be ionized by direct electron impact and showed narrower distribution than Ar ions.

Optimization of MgO secondary electron emission in plasma displays, by the adoption of a suitable getter configuration;Part I: MgO degradation studies

  • Riva, Mauro;Bonucci, Antonio;Carretti, Corrado;Han, Yong-Gyu;Choi, Eun-Ha
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08a
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    • pp.220-223
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    • 2007
  • The key role of MgO is well recognized in PDP's technology. During manufacturing, significant contamination of the oxide occurs. Getters can compete against the impurities sorption speed of the oxide layer. The analysis of the impact of a suitable getter configuration on the operational parameters of PDP's is the final goal of this study.

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Changes in the Optogalvanic Signal Amplitude in a Hollow Cathode Discharge

  • Lee, Jun-Hoi;Koo, Kyung-Wan;Lee, Ki-Sik
    • Transactions on Electrical and Electronic Materials
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    • v.10 no.6
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    • pp.212-216
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    • 2009
  • The spatial distribution of the optogalvanic (OG) signal in argon at the 801.489 nm ($1s_5-2p_8$ transition at the metastable level in Paschen notation) was investigated in the radial direction of a hollow cathode discharge tube. The results of this experiment showed that the OG signal amplitude decreases in accordance with the following two conditions; first, the level of discharge current and second, the distance from the cathode dark space. These results can be quantified by analyzing the electron density profile along the discharge regions, which can directly influence the collisional ionization induced by electron impact.

Silicon Spintronics (실리콘 스핀트로닉스)

  • Min, Byoung-Chul
    • Journal of the Korean Magnetics Society
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    • v.21 no.2
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    • pp.67-76
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    • 2011
  • Semiconductor spintronics is an emerging interdisciplinary technology based on the electron spin degree of freedom, combining the magnetic materials and semiconductors. The spin transistor represents a novel semiconductor device, in which the electron spin is injected, manipulated, and detected, and thereby a memory function and data processing function are enabled in one device. Particularly, the spin transistor based on Silicon, the mainstream semiconductor, might have a significant impact on information technology. This review introduces the major progresses of Silicon spintronics in recent years, and describes the technical issues for the future.

ELECTRICAL BREAKDOWN INITIATION OF ANODIC FILMS DURING ANODIZING IN MOLTEN BISULPHATE MELT

  • Han, S.H.;Thompson, G.E.
    • Journal of the Korean institute of surface engineering
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    • v.32 no.3
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    • pp.341-343
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    • 1999
  • The morphology and composition of anodic films, formed on aluminium at various current densities, in the range $1-100{\;}Am^{-2}$, in the molten bisulphate melt at different temperatures (418-498K), have been studied using transmission electron microscopy of ultramicrotomed film sections, and ion beam thinned films. The first sign of incipient breakdown revealed by transmission electron microscopy of stripped films, is always the appearance of dark regions about 1,000 nm in diameter, representing local overgrowth of the film. The breakdown mechanism is closely related to thermal effects, because temperature rises at regions representing local overgrowth in the stripped films were observed at voltages close to the breakdown voltage, likely arising through impact ionization.

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Characterization of Nano-Grained ZnO Piezoelectric Thin Films Deposited under Various Sputtering Conditions

  • Zhang, Ruirui;Lee, Eunju;Yoon, Giwan
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2009.10a
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    • pp.428-430
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    • 2009
  • C-axis-oriented ZnO thin films were successfully deposited on p-Si (100) in an RF magnetron sputtering system. Deposition conditions such as deposition power, working pressure, and oxygen gas ratio were varied. Crystalline structures of the deposited ZnO films were investigated by a scanning electron microscope (SEM) technique. Results show that the deposition parameters can have a strong impact on the preferred orientations and grain sizes of the deposited ZnO films.

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Excretory-Secretory Products of Trichomonas vaginalis Cause Apoptosis in Mouse Sperm in Vitro

  • Keum, Jihyun;Roh, Jaesook;Ryu, Jae-Sook;Ryu, Ki-Young
    • Parasites, Hosts and Diseases
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    • v.60 no.5
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    • pp.357-360
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    • 2022
  • Excretory-secretory products (ESP) of T. vaginalis have been shown to inhibit sperm motility, viability, and functional integrity, leading to a decreased fertilization rate in vitro. This study investigated whether T. vaginalis induce apoptosis and ultrastructural changes of sperm using flow cytometry and electron microscopy. Incubation of sperm with T. vaginalis ESP increased phosphatidylserine externalization and DNA fragmentation, and decreased mitochondrial membrane potential. Transmission electron microscopy of sperm incubated with ESP revealed abnormal features such as distorted heads, broken necks, and acrosomes exocytosis. This is the first report that demonstrates a direct impact of T. vaginalis ESP on sperm apoptosis and architecture in vitro.

Evaluation of TiN-Zr Hydrogen Permeation Membrane by MLCA (Material Life Cycle Assessment) (물질전과정평가(MLCA)를 통한 TiN-Zr 수소분리막의 환경성 평가)

  • Kim, Min-Gyeom;Son, Jong-Tae;Hong, Tae-Whan
    • Clean Technology
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    • v.24 no.1
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    • pp.9-14
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    • 2018
  • In this study, Material life cycle evaluation was performed to analyze the environmental impact characteristics of TiN-Zr membrane manufacturing process. The software of MLCA was Gabi. Through this, environmental impact assessment was performed for each process. Transition metal nitrides have been researched extensively because of their properties. Among these, TiN has the most attention. TiN is a ceramic materials which possess the good combination of physical and chemical properties, such as high melting point, high hardness, and relatively low specific gravity, high wear resistance and high corrosion resistance. With these properties, TiN plays an important role in functional materials for application in separation hydrogen from fossil fuel. Precursor TiN was synthesized by sol-gel method and zirconium was coated by ball mill method. The metallurgical, physical and thermodynamic characteristics of the membranes were analyzed by using Scanning Electron Microscope (SEM), Energy Dispersive X-ray (EDS), X-ray Diffraction (XRD), Thermo Gravimetry/Differential Thermal Analysis (TG/DTA), Brunauer, Emmett, Teller (BET) and Gas Chromatograph System (GP). As a result of characterization and normalization, environmental impacts were 94% in MAETP (Marine Aquatic Ecotoxicity), 2% FAETP (Freshwater Aquatic Ecotoxicity), 2% HTP (Human Toxicity Potential). TiN fabrication process appears to have a direct or indirect impact on the human body. It is believed that the greatest impact that HTP can have on human is the carcinogenic properties. This shows that electricity use has a great influence on ecosystem impact. TiN-Zr was analyzed in Eco-Indicator '99 (EI99) and CML 2001 methodology.