Description of microwave discharges in hydrogen

Rau, Hans; Picht, Friederike

doi:10.1088/0022-3727/26/8/016

Cited by 19 publications

(20 citation statements)

References 14 publications

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“…Many investigators − simulated kinetics in plasmas such as hydrogen, oxygen, and silane plasma and showed a distribution of activated species in an afterglow region. Their simulation did not deal with all activated species but with either radicals or electrons, and ions, although the plasma contains radicals, electrons, and ions.…”

Section: Theoretical Background Of Remote Hydrogen Treatmentmentioning

confidence: 99%

Surface Modification of Poly(tetrafluoroethylene) by Remote Hydrogen Plasma

Yamada

Tasaka

et al. 1996

Macromolecules

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The kinetics of hydrogen plasma in an afterglow region has been simulated to distinguish remote plasma treatment from conventional (direct) plasma treatment. A simulation shows the possibility that remote hydrogen plasma treatment can enhance interaction reactions with hydrogen radicals relative to those with electron and hydrogen ions. Practically, hydrogen substitution processes in the PTFE sheet by remote and direct hydrogen plasma treatments have been investigated by means of contact angle measurement and XPS. The hydrogen plasma makes the surface of the PTFE sheet hydrophilic. The hydrophilicity depends on the sample position as well as the rf power and the plasma exposure time. The sample position strongly influences the hydrophilicity. The remote hydrogen plasma leads to higher hydrophilicity than the direct hydrogen plasma. The F/C atom ratio for the remote hydrogen-plasma-treated PTFE sheet is 0.41 and that for the direct hydrogen-plasma-treated PTFE sheet is 0.60. The main product of the substitution atoms by remote and direct hydrogen plasma treatments is a dihydrogen-substituted carbon unit and reaches 63% and 55% of the total carbon, respectively. The substitution proceeds at least 3.4 nm from the surface of the PTFE sheet. Remote hydrogen plasma treatment especially accomplishes complete substitution (the F/C atom ratio is 0). These experimental results show the accuracy of the simulation regarding the kinetics of the remote hydrogen plasma.

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Section: Theoretical Background Of Remote Hydrogen Treatmentmentioning

confidence: 99%

Surface Modification of Poly(tetrafluoroethylene) by Remote Hydrogen Plasma

Yamada

Tasaka

et al. 1996

Macromolecules

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“…There are essentially two principal frictional coefficients: F φ , for the spinning rotation of the long axis; and F θ , for the tumbling about the long axis. The observed fast and slow component relaxation times are given by 1/τ fast ) 2kT(1/F θ + 2/F φ ) and 1/τ slow ) 6kT/F θ , respectively (37).…”

Section: Methodsmentioning

confidence: 97%

“…The qualitative appearance of this signal is quite similar to that for the wild-type rod minifilaments Since a symmetric bipolar filament has no inherent dipole, we argued previously (23,24) that a dipole moment is induced by a distortion of the minifilament structure, as, for example, by flexing of the HMM portions of the monomers within the filament in the direction of the applied electric field. This can explain the large negative birefringence component of the signal that indicates a very unusual perpendicular orientation of the long filament axis with respect to the applied electric field (37). The positive birefringence signal is due to a projection of the optical axis onto this perpendicular dipole direction, as, for example, from a nonzero angle between the HMM and the minifilament axis.…”

Section: Prediction Of Coiled-coil Formation By Myosin II Rodsmentioning

confidence: 96%

Flexibility of Acanthamoeba Myosin Rod Minifilaments

Redowicz

Bowers

et al. 1999

Biochemistry

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Previous electric birefringence experiments have shown that the actin-activated Mg2+-ATPase activity of Acanthamoeba myosin II correlates with the ability of minifilaments to cycle between flexible and stiff conformations. The cooperative transition between conformations was shown to depend on Mg2+ concentration, on ATP binding, and on the state of phosphorylation of three serines in the C-terminal end of the heavy chains. Since the junction between the heavy meromyosin (HMM) and light meromyosin (LMM) regions is expected to disrupt the alpha-helical coiled-coil structure of the rod, this region was anticipated to be the flexible site. We have now cloned and expressed the wild-type rod (residues 849-1509 of the full-length heavy chain) and rods mutated within the junction in order to test this. The sedimentation and electric birefringence properties of minifilaments formed by rods and by native myosin II are strikingly similar. In particular, the Mg2+-dependent flexible-to-stiff transitions of native myosin II and wild-type rod minifilaments are virtually superimposable. Mutations within the junction between the HMM and LMM regions of the rod modulate the ability of Mg2+ to stabilize the stiff conformation. Less Mg2+ is required to induce minifilament stiffening if proline-1244 is replaced with alanine. Deleting the entire junction region (25 amino acids) results in a even greater decrease in the Mg2+ concentration necessary for the transition. The HMM-LMM junction does indeed seem to act as a Mg2+-dependent flexible hinge.

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“…A low-temperature plasma 17,18 of suitable characteristics can be produced, e.g., by inductive 19 and capacitive 20 rf discharges, 21 cathodic 22 and anodic 23,24 vacuum arcs, and microwave discharges. 25 The plasma parameters, together with other simulation parameters, are listed in Table I.…”

Section: Modelmentioning

confidence: 99%

Plasma-controlled metal catalyst saturation and the initial stage of carbon nanostructure array growth

Levchenko

Ostrikov

Mariotti

et al. 2008

Journal of Applied Physics

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The kinetics of the nucleation and growth of carbon nanotube and nanocone arrays on Ni catalyst nanoparticles on a silicon surface exposed to a low-temperature plasma are investigated numerically, using a complex model that includes surface diffusion and ion motion equations. It is found that the degree of ionization of the carbon flux strongly affects the kinetics of nanotube and nanocone nucleation on partially saturated catalyst patterns. The use of highly ionized carbon flux allows formation of a nanotube array with a very narrow height distribution of half-width 7 nm. Similar results are obtained for carbon nanocone arrays, with an even narrower height distribution, using a highly ionized carbon flux. As the deposition time increases, nanostructure arrays develop without widening the height distribution when the flux ionization degree is high, in contrast to the fairly broad nanostructure height distributions obtained when the degree of ionization is low.

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Description of microwave discharges in hydrogen

Cited by 19 publications

References 14 publications

Surface Modification of Poly(tetrafluoroethylene) by Remote Hydrogen Plasma

Surface Modification of Poly(tetrafluoroethylene) by Remote Hydrogen Plasma

Flexibility of Acanthamoeba Myosin Rod Minifilaments

Plasma-controlled metal catalyst saturation and the initial stage of carbon nanostructure array growth

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