A5054804808- Dust and Plasma Wave Phenomena
- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- Ion-surface interactions and analysis
- Plasma Diagnostics and Applications
- Atomic and Molecular Physics
- Magnetic confinement fusion research
- Electrohydrodynamics and Fluid Dynamics
- Ionosphere and magnetosphere dynamics
- Photochromic and Fluorescence Chemistry
- Infectious Diseases and Mycology
- Nuclear Physics and Applications
- Mycobacterium research and diagnosis
- Conducting polymers and applications
- Carbon Nanotubes in Composites
- Ga2O3 and related materials
- Scientific Research and Discoveries
- Gas Sensing Nanomaterials and Sensors
- Advanced Memory and Neural Computing
- Diagnosis and treatment of tuberculosis
- Electrostatic Discharge in Electronics
- Synthesis and properties of polymers
- Orbital Angular Momentum in Optics
- Polydiacetylene-based materials and applications
- Particle Dynamics in Fluid Flows
Kiel University
2009-2025
Fachhochschule Kiel
2011-2024
Goethe University Frankfurt
1986-2004
Max Planck Institute of Quantum Optics
1990
Institut für Technische und Angewandte Physik (Germany)
1990
Dusty plasmas are electrically quasi-neutral media that, along with electrons, ions, neutral gas, radiation, and electric and/or magnetic fields, also contain solid or liquid particles sizes ranging from a few nanometers to micrometers. These can be found in many natural environments as well various laboratory setups industrial applications. As separate branch of plasma physics, the field dusty physics was born beginning 1990s at intersection interests communities investigating astrophysical...
This study presents a detailed investigation of the force profiles on optically trapped microparticles within sheath dual-frequency capacitively coupled plasma, utilizing particles as diagnostic probes. By systematically varying phase angle between applied frequencies (13.56 MHz and 27.12 MHz), were precisely measured, revealing strong dependence angle. Sheath parameters, including position edge location magnitude electric field maximum, determined found to correlate closely with angle,...
In this study, a four-grid retarding potential analyzer (RPA) with drilled grid holes is investigated, focusing on correlations between orientations and resulting characteristics. The individual grids have hexagonal hole pattern can be mounted rotated relative to each other in multiples of 90°. An ion beam small divergence narrow energy distribution directed perpendicularly the RPA system used. We find that for certain configurations, particularly when are aligned, characteristics deviate...
We report on reversible light-controlled conductance switching in devices consisting of multiwalled carbon nanotube (MWCNT)–polymer nanocomposites blended with azobenzene molecules and photoisomerization the latter. Both MWCNT, which are functionalized carboxyl groups (MWCNT-COOH), embedded independently a poly(methyl methacrylate) matrix, thin films prepared by using simple spin-coating technique. demonstrate feasibility present concept photocurrent amplitude almost 10%.
A dual-frequency ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2f$</tex-math> </inline-formula> ) capacitively coupled rf argon plasma has been investigated using a passively compensated Langmuir probe (LP). The discharge is driven by two different excitation frequencies (13.56 and notation="LaTeX">$27.12~\mathrm{MHz}$</tex-math> simultaneously with variable phase angle...
We present one of the first experiments for optically trapping single microparticles as probes low temperature plasma diagnostics. Based on dual laser beam, counter-propagating technique, SiO2 are trapped at very large distances in low-temperature, low-pressure rf plasma. External forces particle measured by means displacement probe trap. Measurements can be performed during operation well without The paper focuses optical setup and verification system its principle. Three examples behavior...
Abstract The article reports on non‐electrostatic diagnostics for ion beams. A novel galvanometric force measuring probe is presented, and results are compared with corresponding measurements by a calorimetric technique using falling microparticles. target chamber operated at argon pressures where charge‐exchange collisions important. It highlighted that methods sensitive ions as well energetic neutral atoms. For the first time, bombardment induced light emission (BLE) from solid targets...
Summary Ni- and Co-nanoparticles of average sizes about 4 to 10 nm were produced by “physical” means with the cluster source LUCAS based upon laser evaporation into seeding gas adiabatic expansion an UHV experimentation chamber. They deposited subsequently oxidized in situ at 400 °C. The structures nanos characterized HRTEM chemically analyzed EFTEM. Clear core/shell established crystalline metallic core oxide shell final thickness 2 nm. In one sample it might be that is amorphous. An...
A novel experiment for the study of forces on microparticles in ion beams is presented. broad beam source provides a vertically upward directed wherein 100 μm hollow glass spheres are injected. The particles illuminated by diode laser and recorded with charge-coupled device camera. From trajectories acceleration net force determined. Information energetic neutral atoms achieved, which not accessible electrostatic methods.
Abstract An interesting aspect in the research of complex (dusty) plasmas is experimental study interaction microparticles with surrounding plasma for diagnostic purposes. Local electric fields can be determined from behavior particles plasma, i.e. may serve as electrostatic probes. From particle trajectories, also determination momentum flux beams possible, and force Recently, temperature sensitive features particular phosphors were utilized measuring surface confined sheath a rf plasma....
Novel, optically responsive devices with a host of potential applications have been demonstrated by coupling carbon nanomaterials photochromic molecules. For light-induced conductance switching in particular, we recently shown that nanotube-polymer nanocomposites containing azobenzene are very attractive and provide stable non-degradable changes conductivity over time at standard laboratory conditions. In these composites, the photoswitching mechanisms based on electronic properties related...
The force on microparticles in an energetic ion beam is investigated experimentally. Hollow glass microspheres are injected into the vertically upward directed and their trajectories recorded with a charge-coupled device camera. net particles determined by means of measured vertical acceleration. resulting pressures compared Faraday cup measurements current density calorimetric power density. Due to neutral gas background, consists, besides ions, atoms produced charge-exchange collisions. It...
The first experimental study is reported of a plasma produced by heavy-ion beam. Relevant parameters for heating with heavy ions are described, temperature and density the determined, hydrodynamic motion in target induced beam studied. measured free-electron compared two-dimensional hydrodynamic-model calculation. In accordance model, radial rarefaction wave reaching center was observed penetration velocity ion into xenon-gas measured.
The sheath of a dual-frequency capacitively coupled rf discharge has been investigated with microparticles as probes based on two different methods: by the first method, intensity profiles emitted light and scattered are used to study effects phase variation between fundamental frequency (13.56 MHz) its harmonic (27.12 or change in dc self-bias, respectively, expansion levitation height sheath. These measurements show that width well correlates self-bias function applied voltage harmonics....
This report presents two cases of cervical lymphadenitis due to Mycobacterium interjectum in healthy young children, identified by sequencing the 16S rRNA gene. Surgical resection combined with chemotherapy resulted cure. Conclusion: The attention clinicians needs be drawn an emerging mycobacterial pathogen which might overlooked or misidentified routine laboratory testing.
A two-dimensional hydrodynamic code is discussed. It includes the treatment of energy deposition by heavy ions and calculation transport coefficients. Loss terms due to volume radiation in emission limit a realistic equation state (SESAME tables or an ionized gas including solution Saha equations determine degree ionization) are considered. Numerical simulations performed study flow cylindrical tubes filled with noble gases Argon Xenon respectively. Target beam parameters chosen close...
Forces on microparticles in energetic ion beams are investigated experimentally. For this purpose, hollow glass microspheres injected into a vertically upward directed beam. The particles illuminated by diode laser, and their scattered light is recorded with charge-coupled device camera. From the trajectories, acceleration net force determined. It found that significantly higher than expected drag force. This additional part of total explained fast neutral atoms produced charge-exchange...
This paper reports on experiments aiming at an efficient technique for contact charging of conductive microparticles. Fine electrode structures generate high electric field strengths which charge the particles in with voltage electrode. Highly charged microparticles are a prerequisite electrostatic microparticle acceleration laboratory and advanced concepts space propulsion terrestrial applications. Possible applications treatment surfaces hypervelocity experiments, e.g. simulation micrometeorites.