• 조명전기설비학회논문지
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• 제13권3호
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• pp.34-39
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• 1999

본 연구에서는 랑그뮤어 푸로브법을 이용요하여 고주파 유도결합 플라즈마에서 전자온도와 전자밀도를 측정하였다. 실험의 공통조건은 압력 10∼40[mTorr], 입력파워는 100∼600[W]이고, 공간분포는 측정에서의 아스펙트비(R/L)는 2로하였다. 전자온도와 전자밀도의 의존성을 측정한 결과 입력파워에서는 전자온도는 약간 증가하는 경향을 보이고 있지만 전자말도는 입력파워가 100∼250[W]까지는 증가율이 완만하고 450[W]에서 포화하는 것을 알수 있었다. 압력에 대한 의존성은 압력이 낮을수록 높은 값을 나타내고 전자밀도에서는 압력이 증가함에 따라 증가하는 것을 알 수 있었다. 전자온도의 반경방향의 공간분포는 석영창 부근에서 기판쪽으로 갈수록 감소되는 경향이 있다. 전자밀도에서는 플라즈마 중심부에서 석영창 쪽으로 약간 이동한 위치에서 피크의 값을 가지고, 석영창과 기판쪽에서는 그 값이 감소함을 볼 수 있었다. 전자온도의 축방향의 공간분포는 석영창 부근에서 기판쪽으로 감소되는 경향이 있다. 또, 전자밀도는 플라즈마 중심부에서 석영창 쪽으로 약간 이동한 위치에서 피크의 값을 가지고, 석영창과 기판쪽에서는 그 값이 감소함을 볼 수 있었다. 이상의 결과들은 유도방전플라즈마의 메카니즘의 체계적인 이해에 기여할 수 있을 것이다.

• 조명전기설비학회논문지
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• 제27권7호
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• pp.52-58
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• 2013

The two-dimensional finite difference time domain algorithm is used to numerically reconstruct the electron density profile in O-mode ultrashort pulse reflectometry. A Gaussian pulse is employed as the source of a probing electromagnetic wave. The Gaussian pulse duration is chosen in such a manner as to have its frequency spectrum cover the whole range of the plasma frequency. By using a number of numerical band-pass filters, it is possible to compute the time delays of the frequency components of the reflected signal from the plasma. The electron density profile is reconstructed by substituting the time delays into the Abel integral equation. As a result of simulation, the reconstructed electron density profile agrees well with the assumed profile.

• Bulletin of the Korean Chemical Society
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• 제22권8호
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• pp.827-832
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• 2001

The excitation temperature and electron number density have been measured for end-on-view ICP discharge. In this work, end-on-view ICP-AES equipped with the newly developed “optical plasma interface (OPI)” was used to eliminate or remove the neg ative effects caused by end-on-plasma source. The axial excitation temperature was measured using analyte (Fe I) emission line data obtained with end-on-view ICP-AES. The axial electron number density was calculated by Saha-Eggert ionization equilibrium theory. In the present study, the effects of forward power, nebulizer gas flow rate and the presence of Na on the excitation temperature and electron number density have been investigated. For sample introduction, two kinds of nebulizers (pneumatic and ultrasonic nebulizer) were utilized.

• Applied Microscopy
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• 제17권1호
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• pp.83-97
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• 1987

In order to discriminate the enteroendocrine cell types in the mucosal epithelium of the normal duodenum of the Korean hedgehog (Erinaceus koreanus). The tissues were fixed in the mixture of 1% paraformaldehyde and 1% glutaraldehyde in phosphate buffer (pH 7.2), and postfixed in 2% osmium tetroxide (phosphate buffer, pH 7.2). They were embedded in Araldite, and the ultrathin sections were made by LKB-V ultratome following the inspection of semithin sections stained with toluidine blue-borax solutions. Ultrathin sections contrasted with uranyl acetate and lead citrate were observed with JEM 100B electron microscope. At least six types of enteroendocrine cells distributed in the mucosal epithelium of the duodenum were identified according to their morphological characteristics mainly based on the size, shape, number and electron density of the secretory granules. Type I cells had moderately developed organelles. The secretory granules were pleomorphic ($370X510nm$), and the granule cores with high electron density were enveloped in limiting membrane and characterized by a narrow halo. Type II cells contained an indented nucleus and well-developed organelles. The secretory granules were round (350 nm) and classified in two kinds by electron density, moderate and high. Both granules were surrounded by limiting membrane and those with high electron density showed often a wide halo. Type III cells had an indented nucleus. The secretory granules with various electron density were round (220 nm) in shape. The granules with high electron density were enveloped in limiting membrane and characterized by a narrow halo, but those with low or moderate electron density had not been observed the limiting membrane. Type IV cells contained an indented nucleus and moderately developed organelles. The secretory granules were round (180 nm) in shape, and the granule cores with high electron density were enveloped in limiting membrane and showed often a wide halo. Type V cells had a large amount of rough endoplasmic reticulum. Secretory granules with low or moderate electron density were round (230 nm) in shape, and surrounded by limiting membrane and showed a narrow halo. Type VI cells contained an oval nucleus and well-developed organelles, especially Golgi complex. The secretory granules with high electron density were round (210 nm) in shape. The granules were enveloped in limiting membrane and showed often a wide halo.

• 천문학회보
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• 제40권1호
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• pp.63.1-63.1
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• 2015

In this study, we determine coronal electron density distributions by analyzing DH type II radio observations based on the assumption: a DH type II radio burst is generated by the shock formed at a CME leading edge. For this, we consider 11 Wind/WAVES DH type II radio bursts (from 2000 to 2003 and from 2010 to 2012) associated with SOHO/LASCO limb CMEs using the following criteria: (1) the fundamental and second harmonic emission lanes are well identified; (2) its associated CME is clearly identified in the LASCO-C2 or C3 field of view at the time of type II observation. For these events, we determine the lowest frequencies of their fundamental emission lanes and the heights of their leading edges. Coronal electron density distributions are obtained by minimizing the root mean square error between the observed heights of CME leading edges and the heights of DH type II radio bursts from assumed electron density distributions. We find that the estimated coronal electron density distribution ranges from 2.5 to 10.2-fold Saito's coronal electron density models.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.2418-2420
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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 $20{\sim}100mTorr$ Xenon pressure, $50{\sim}200W$ 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.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 광주전남지부
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• pp.43-47
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• 2006

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). As results at several dependences of 20~100mTorr Xenon pressure, the brightness of discharge tube was higher (4,900 $cd/m^2$) than other conditions when Xe pressure was 20mTorr and RF power was 200W. In that case, the electron temperature and density were 3.58eV and $3.56{\times}10^{12}cm^2$, respectively. 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.

• 한국초전도ㆍ저온공학회논문지
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• 제21권3호
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• pp.6-12
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• 2019

Extended Drude model has been used to obtain information of correlations from measured optical spectra of strongly correlated electron systems. The optical self-energy can be defined by the extended Drude model formalism. One can extract the optical self-energy and the electron-boson spectral density function from measured reflectance spectra using a well-developed usual process, which is consistent with several steps including the extended Drude model and generalized Allen's formulas. Here we used a reverse process of the usual process to investigate the extended Drude analysis when an additional low-energy interband transition is included. We considered two typical electron-boson spectral density model functions for two different (normal and d-wave superconducting) material states. Our results show that the low-energy interband transition might give significant effects on the electron-boson spectral density function obtained using the usual process. However, we expect that the low-energy interband transition can be removed from measured spectra in a proper way if the transition is well-defined or well-known.

• KIEE International Transactions on Electrophysics and Applications
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• 제2C권5호
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• pp.246-252
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• 2002

Two-dimensional steady state simulations of planar type radio frequency inductively coupled plasma (RFICP) have been performed. The characteristics of RFICP were investigated in terms of power transfer efficiency, equivalent circuit analysis, spatial distribution of plasma density and electron temperature. Plasma density and electron temperature were determined from the equations of ambipolar diffusion and energy conservation. Joule heating, ionization, excitation and elastic collision loss were included as the source terms of the electron energy equation. The electromagnetic field was calculated from the vector potential formulation of ampere's law. The peak electron temperature decreases from about 4eV to 2eV as pressure increases from 5 mTorr to 100 mTorr. The peak density increases with increasing pressure. Electron temperatures at the center of the chamber are almost independent of input power and electron densities linearly increase with power level. The results agree well with theoretical analysis and experimental results. A single turn, edge feeding antenna configuration shows better density uniformity than a four-turn antenna system at relatively low pressure conditions. The thickness of the dielectric window should be minimized to reduce power loss. The equivalent resistance of the system increases with both power and pressure, which reflects the improvement of power transfer efficiency.

• 전기학회논문지
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• 제65권7호
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• pp.1211-1217
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• 2016

Discharge characteristics of inductively coupled plasma were investigated by using electrostatic probe and fluid simulation. The Inductively Coupled Plasma source driven by 13.56 Mhz was prepared. The signal attenuation ratios of the electrostatic probe at first and second harmonic frequency was tuned in 13.56Mhz and 27.12Mhz respectively. Electron temperature, electron density, plasma potential, electron energy distribution function and electron energy probability function were investigated by using the electrostatic probe. Experiment results were compared with the fluid simulation results. Ar plasma fluid simulations including Navier-Stokes equations were calculated under the same experiment conditions, and the dependencies of plasma parameters on process parameters were well agreed with simulation results. Because of the reason that the more collision happens in high pressure condition, plasma potential and electron temperature got lower as the pressure was higher and the input power was higher, but Electron density was higher under the same condition. Due to the same reason, the electron energy distribution was widening as the pressure was lower. And the electron density was higher, as close to the gas inlet place. It was found that gas flow field significantly affect to spatial distribution of electron density and temperature.