• 한국수소및신에너지학회논문집
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• 제25권3호
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• pp.234-239
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• 2014

To study catalytic activity and hydrogen embrittlement of Pd, Pt, Ni, and Cr in fuel cell electrode, we used density-functional theory. The calculation tools based electron density give much shorter calculation time and cheap costs. Maximum of bond overlap populations of each metal are 0.6539eV for Pd-H, 0.6711eV for Pt-H, 0.6323eV for Ni-H, 0.6152eV for Cr-H. Electron density of Cr has strongest in related metals, which shows strong localization of electron, implying anti hydrogen embrittlement behaviors.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.438-438
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• 2010

The abnormal behavior of the argon metastable density during the E-H mode transition in argon ICP discharge was investigated. Lots of investigations including global models expected that during and after the mode transition of ICP discharge, the density of metastable increases with applied rf power (i.e. electron density). However, recent direct measurement of metastable density revealed that the metastable density of argon decreases with the applied power during and after the mode transition. This result may not be explained by the previous global model which is based on the assumption of the Maxwellian electron energy distribution function (EEDF). In this paper, to explain this abnormal behavior with simple manners, a simple global model taking account of the effect of the non-Maxwellian EEDFs incorporating into a set of coupled rate equations is proposed. The result showed that the calculated metastable density taking account of non-Maxwellian EEDF and its evolution during the transition has an abnormal behavior with electron density and is in good agreement with the previous measurement results, indicating the close coupling of electron kinetics and the behavior of metastable density. The proposed simple model is expected to provide qualitative kinetic insight to understand the behavior of the metastable density in various plasma discharges which typically exhibit non-Maxwellian distribution.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2011년도 춘계학술대회 논문집
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• pp.787-788
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• 2011

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 영호남 합동 학술대회 및 춘계학술대회 논문집 센서 박막 기술교육
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• pp.86-90
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• 2006

Discharge of the flat lamp lighting source research are requested very much. For improving brightness, life time, efficiency of flat lamp, plasma diagnosis of the f1at lamp lighting source to understand property of lighting source is very important. Distance of discharge electrode is 5.5mm and width is 16.5mm, we have measured electron temperature and electron density measured with single Langmuir probe in flat lamp. We have tested the discharge from 100 Torr to 300 Torr pressure. The pulse is rectangular pulse with frequency 20kHz and duty ratio 20%. In result, electron temperature decreases and electron density increase as increase the gas pressure and electron temperature decreases and electron density increase as increase the voltage.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 춘계학술대회 논문집
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• pp.41-45
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• 2005

In this paper, parameters of electron temperature and density for the mercury-free lighting-source were measured to diagnosis and analyze in Xe based inductively coupled plasma(ICP). In results at several dependences of 20~100 mTorr Xenon pressure, 50~200W RF power and horizontal distribution were especially mentioned. When Xe pressure was 20mTorr and RF power was 200W, the electron temperature and density were respectively 3.58eV and $3.56{\times}10^{12}cm^{-3}$. The key parameters of Xe based ICP depended on Xe pressure more than RF power that could be verified. A high electron temperature and low electron density with a suitable Xe pressure are indispensible parameters for Xe based ICP lighting-source.

• KIEE International Transactions on Electrophysics and Applications
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• 제11C권4호
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• pp.107-112
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• 2001

Laser Thomson scattering measurements of electrom temperature and density in a neutral loop discharge (NLD) plasma were performed in order to reveal the electron behavior around the neutral loop (NL). The experimental results were examined by using a simulation model that included effects of a three dimensional electromagnetic field with spatial decay of the RF electric field, and the limitation of the spatial extent of the electron motion and collision effect. From the experiments and modeling of the electron behavior, it was found that NLD plasma posses the electron temeprature $T_{e}$ and density ne peaks around the NL is essential for the formation of plasma. Also, the optimum condition of plasma production could be simply estimated by the calculation of $U_{av}$ and $F_{0}$././.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2000년도 제18회 학술발표회 논문개요집
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• pp.156-156
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• 2000

Recently, the surface electronic states have attracted much attention since their standing wave patterns created around steps, defects, and adsorbates on noble metal surfaces such as Au(111), Ag(110), and Cu(111) were observed by scanning tunneling microscopy (STM). As a typical example, a striking circular pattern of "Quantum corral" observed by Crommie, Lutz, and Eigler, covers a number of text books of quantum mechanics, demonstrating a wavy nature of electrons. After the discoveries, similar standing waves patterns have been observed on other metal and demiconductor surfaces and even on a side polane of nano-tubes. With an expectation that the surface states could be utilized as one of ideal cases for studying two dimensionakl (sD) electronic system, various properties, such as mean free path / life time of the electronic states, have been characterized based on an analysis of standing wave patterns, . for the 2D electron system, electron density is one of the most importnat parameters which determines the properties on it. One advantage of conventional 2D electron system, such as the ones realized at AlGaAs/GaAs and SiO2/Si interfaces, is their controllability of the electrondensity. It can be changed and controlled by a factor of orders through an application of voltage on the gate electrode. On the other hand, changing the leectron density of the surface-state 2D electron system is not simple. On ewqy to change the electron density of the surface-state 2D electron system is not simple. One way to change the electron density is to deposit other elements on the system. it has been known that Pd(111) surface has unoccupied surface states whose energy level is just above Fermi level. Recently, we found that by depositing Pd on Cu(111) surface, occupied surface states of Cu(111) is lifted up, crossing at Fermi level around 2ML, and approaches to the intrinsic Pd surface states with a increase in thickness. Electron density occupied in the states is thus gradually reduced by Pd deposition. Park et al. also observed a change in Fermi wave number of the surface states of Cu(111) by deposition of Xe layer on it, which suggests another possible way of changing electron density. In this talk, after a brief review of recent progress in a study of standing weaves by STM, I will discuss about how the electron density can be changed and controlled and feasibility of using the surface states for a study of 2D electron system. One of the most important advantage of the surface-state 2D electron system is that one can directly and easily access to the system with a high spatial resolution by STM/AFM.y STM/AFM.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제53권3호
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• pp.157-161
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• 2004

We present a simple analytical expression of plasma density by making use of the electron density equation to study the dynamic behavior of the corona discharge plasma. It assumes that a specified voltage profile is fed through the inner conductor of the reactor chamber consisting of two coaxial conducting cylinders. The analytical description is based on the electron continuity equation with ionization and attachment by electrons. It is found that the electron density profile calculated between two coaxial cylindrical electrodes depends very sensitively on the Profile of applied voltage. The analytical expression of plasma density and its generation will provide important scaling laws in the corona discharge plasma.

• Design & Manufacturing
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• 제14권1호
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• pp.56-62
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• 2020

An electron beam was used to mainly utilize for polishing, finishing, welding, a lithography process, etc. Due to the high technical level of difficulty of high-power density electron beam, it is difficult to secure related technologies. In this study, research was carried out to improve the machinability by developing the vaporized amplification sheets to realize the electron beam drilling technology. Their vaporized amplification sheets were analyzed by using the measurement of chemical and composition, which is such as TGA, SEM. We analyzed micro-hole processing using a microscope. Also, the thermal characteristics of vaporized amplification sheets are highly significant for applying to high-power density electron beam technique. So, we finished the vaporized amplification sheets according to the process conditions and analyzed it according to the machining conditions of the electron beam. It was confirmed that the effect on the experimental results differs depending on the influence of the metal powder contained in the developed material.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 E
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• pp.2170-2172
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• 1999

A low energy large aperture(LELA) pulsed electron beam generator of a cold cathode type has been developed for environmental applications, for example, waste water cleaning, flue gas cleaning, and pasteurization etc. The operational principle is based on the emission of secondary electrons from cold cathode when ions in the plasma hit the cathode, which are accelerated toward exit window by the gradient of an electric potential. We have fabricated the LELA electron beam generator with the peak energy of 200keV and beam diameter of 200mm and obtained the large aperture electron beam in air. The electron beam current density has been investigated as a function of glow discharge current, accelerating voltage and radial distribution in front of the exit window foil. The plasma density and electron temperature have been measured in order to confirm the relation with the electron beam current density. We are going to upgrade the LELA electron beam generator in the electron energy, electron beam current and stability of operation for various applications.