1,721,010 research outputs found
Experimental measurement of the electron energy distribution function in the radio frequency electron cyclotron resonance inductive discharge
No full textRecently, the existence of electron cyclotron resonance (ECR) in a weakly magnetized inductively coupled plasma (MICP) has been evidenced [ChinWook Chung , Phys. Rev. Lett. 80, 095002 (2002)]. The distinctive feature of the ECR effect in the MICP is efficacious heating of low-energy electrons. In the present paper, electron heating characteristics in the MICP have been investigated by observing electron energy distribution function dependencies on various external parameters such as gas pressure, driving frequency, and rf power (electron density). It is found that the ECR effect on electron heating becomes enhanced with decreasing pressure or increasing driving frequency. The ECR heating becomes weak at high rf power due to the electron-electron collisions
Heating-mode transition in the capacitive mode of inductively coupled plasmas
No full textThe evolution of the electron energy distribution function (EEDF) against pressure is investigated in the capacitive mode of inductively coupled plasma (ICP). A significant change in the EEDFs is observed: a bi-Maxwellian EEDF at low pressure (less than or equal to10 mTorr) evolves into a Druyvestein-like EEDF at high pressure (greater than or equal to50 mTorr) in the capacitive mode (low-density mode) while the EEDFs in the inductive mode (high-density mode) does not evolve like in the capacitive mode due to high electron-electron collisions. This EEDF transition in the capacitive mode of ICP is similar to that in the capacitive coupled plasma (CCP) reported in literature [V. A. Godyak and R. B. Piejak, Phys. Rev. Lett. 65, 996(1990)] as pressure increases. This observation directly shows that the electron heating mechanism of the capacitive mode in the ICP is the same as that in the CCP, as expected. (C) 2002 American Institute of Physics
Development and verification of validity and reliability of the WHOQOL-BREF Taiwan version
No full textPower dissipation mode transition by a magnetic field
No full textWe measured electrical characteristics of transversely magnetized capacitively coupled plasma at low pressure (10 mTorr). From these measurements, we found that the power characteristics of the magnetized discharge were different from those of the unmagnetized discharge. As the magnetic field increases, a square dependence of power characteristic at high current changes to a linear dependence. This can be understood as a power dissipation mode transition by a magnetic field. A calculation from a simple sheath model agrees well with the experimental data. (C) 2002 American Institute of Physics
Neuronal correlates of binocular rivalry in second-order patterns
No full textIt has been recently reported that there is binocular rivalry in second-order patterns with a dynamic carrier [Kim et al, 2006 Journal of Vision 6(6), VSS 07, abstract 47a]. To find neuronal correlates of second-order binocular rivalry, we measured BOLD signal changes in early visual cortex while subjects viewed uncorrelated dynamic random-dot fields whose contrasts were modulated at 1.5 cycles deg-1 sine-wave with orientation of ±45°. Subjects were required to press either right or left button for alternating percepts tilted rightward or leftward, respectively. We found that there is no difference of V1 activity in both hemispheres when either right or left response was made. However, there was a fluctuation of activity in V2 for alternating percepts. V2 activity increased with the right response and decreased with the left response in the left hemisphere, while the activity pattern was reversed in the right hemisphere. These results indicate that V2 area is a special site for second-order binocular processing as suggested in form and motion vision
Electron temperature and density variation due to temporal evolution of nano particle growth in RE silane plasma
No full textNonlocal electron kinetics in a planar inductive helium discharge
No full textA measurement of the electron energy distribution function (EEDF) using the ac superposition method is done over a helium pressure range of 10-100 mTorr in a planar inductive plasma, and the electron energy diffusion coefficient which describes the electron heating is calculated based on the same discharge conditions using a two-dimensional simulation. It is found that the measured EEDF shows a bi-Maxwellian distribution with a low-energy electron group at low pressures below 20 mTorr even in the inductive discharge using helium of the non-Ramsauer gas. The major factors which can affect the EEDF formation are investigated. In particular, the concept of the total electron bounce frequency, i.e., the electron residence time, is introduced as an indicator of how the electron-electron collision affects the EEDF shape. As a result, it is shown that the observed bi-Maxwellian distribution at low pressures is attributed to the combined effects of the formation of low-energy electrons through the cooling mechanism of energetic electrons enhanced by the capacitive field, the low heating rate of the low-energy electrons, the confinement of low-energy electrons by the ambipolar space potential, and the low electron-electron collision frequency which can be estimated from the total electron bounce frequency presented in this paper
Plasma parameter dependence of critical particle size at the moment of void formation in RF silane plasmas
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On a dual inductively coupled plasma for direct and remote plasma in a reactor
No full textA dual inductively coupled plasma (ICP) system in which a remote ICP (upper ICP) with small volume is attached to a main ICP (lower ICP) is developed. Two ICP antennas are connected in parallel and a variable capacitor C-var is installed in series at the end of the main ICP antenna. By adjusting the capacitance of the variable capacitor, the plasma densities and the electron temperatures in the remote region and the main region are controlled. The electron energy distribution functions (EEDFs) and plasma potential from the EEDFs are measured along z axis. It is found that there is a potential dip in the midway of two ICP antennas and the potential dip is formed to keep two plasmas quasineutral. In two regions, the EEDFs in high energy range are almost same (nonlocal) but they are different in low energy range because low energy electrons cannot overcome the potential dip. (C) 2004 American Institute of Physics
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