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The applicability of Dynamic Light Scattering (DLS) on strongly coupled complex plasmas (plasma crystals) in a RF discharge is discussed. A ballistic particle movement is observed and the particle velocity can be measured in all phase states. The results are in very good agreement with video based measurements. Phase transitions were studied in detail. A theoretically predicted hysteresis loop in the phase transition were observed experimentally for the first time. The diffusive particle movement was studied by small angle light scattering. These measurements are also validated by video observations.

A time-resolved analysis of the emission of power impulse magnetron sputtering plasmas reveals inhomogeneities in the form of rotating spokes. The shape of these spokes depends on the target material in a characteristic manner; the peculiar shape of the emission profiles is explained by the localization of the sputtering process as being governed by Ar gas rarefaction and the local dynamics of secondary electrons generation. This general picture is able to explain the observed emission patterns for different target materials as presented.

International audience; Diode laser absorption at 772.38 nm is used to measure the time resolved density of Ar*(3 P 2) metastable atoms in a capacitively coupled radio-frequency (RF) discharge running in argon/acetylene mixture at 0.1 mbar. The RF power is pulsed at 100 Hz and the density of Ar*(3 P 2) atoms in the 5 ms ON time and in the afterglow are recorded. Different plasma conditions, namely: 1) pure argon, 2) argon + 7% acetylene before powder formation, 3) argon + 7% acetylene after dust particles have been formed and 4) argon with dust particles remained in the plasma volume but without acetylene are studied. The measured steady-state Ar*(3 P 2) density in the middle of the reactor is always about 10 times larger in dusty argon plasma than in pure argon discharge. This is mainly a consequence of the enhancement of electron temperature after dust formation. Both steady state densities and decay times in the afterglow indicate that the degree of dissociation of C 2 H 2 in the plasma volume can be as high as 99%. It is shown that in our plasma conditions on the surface of dust particles the loss of Ar*(3 P 2) atoms is negligible compared to their loss by diffusion to the electrodes.

International audience; The spatial dynamics of the optical emission from an array of 50 times 50 individual micro cavity plasma devices are investigated. The array is operated in argon and argon-neon mixtures close to atmospheric pressure with an AC voltage. The optical emission is analysed with phase and space resolution. It has been found that the emission is not continuous over the entire AC period, but occurs once per half period. Each of the observed emission phases shows a self-pulsing of the discharge, with several bursts of emission of fixed width and repetition rate. The number of emission bursts depends on applied voltage and frequency. Spatially resolved measurements prove that the emission bursts are formed by overlapping emission pulses from single discharge cavities. Intensity differences between positive and negative half-wave can be interpreted through spatially resolved measurements of single discharge cavities.

International audience; This paper deals with the analysis of nanoparticles polymerized in nitrogen/acetylene and argon/ acetylene gas mixtures in low temperature rf discharges. The polymerization process was monitored by means of mass spectroscopy. The chemical characteristics of the material were obtained in situ by infrared absorption spectroscopy and ex situ by means of near edge x-ray absorption fine structure spectroscopy. These data were supported by complimentary elemental analyses such as deuteron induced gamma emission, Rutherford backscattering, and nuclear reaction analysis. Although morphology showed no differences, further material analysis shows clearly nitrogen incorporation in the nanoparticles, mostly by multiple bonds. In comparison with the nanoparticles from argon/acetylene plasma, the amount of carbon in carbon-nitride nanoparticles remains unchanged, whereas hydrogen content strongly decreases. The results of mass spectroscopy on neutrals and ions lead to the assumption that carbon-nitride nanoparticles are formed by copolymerization of two kinds of precursors: hydrocarbon and nitrogen containing hydrocarbon species.

International audience; Reactive plasmas are nowadays widely used for technological applications. The spontaneous formation and growth of dust is a phenomenon frequently observed in such plasmas. The formation of dust particles has been observed in a great variety of different discharge types and in different kind of gases or gas mixtures. Due to the large variety of different phenomena that can be observed in reactive complex plasmas this article will address some selected (general) problems and examples that are specific for the physics and chemistry of such systems. These examples concern the formation and growth of dust particles in reactive plasmas, the mechanisms responsible for that growth processes, the spatial distribution of the dust particles within the discharge, the response of the plasma to the formation and growth of dust particles and some technological aspects

This paper deals with the study of the temporal and spatial evolution of the dust formation in a capacitively coupled standard GEC cell in Ar/C2H2 and Ar/CH4 mixtures. To initiate the particle growth in the Ar/CH4 discharge, we have either to apply transiently high power to the discharge or to inject transiently a pulse of C2H2. In the Ar/C2H2 discharge, however, the particles are formed spontaneously at constant low power. The experiments underline the importance of acetylenic compounds for the nucleation process, i.e. for the first step of particle growth. Due to the different initiation process, the further temporal evolution of the dust formation is significantly different for both kinds of discharges. The dust particles are detected by means of laser beam scattering and by measuring the extinction of the laser beam after passing the discharge. The response of the plasma to the formation of dust has been analysed by emission spectroscopy and mass spectroscopy. The 7th harmonic signal of the rf driving voltage is a useful indicator for the presence of dust particles and their growth.

We will present UV and IR extinction measurements on isolated carbonaceous nanoparticles levitating in a low temperature argon plasma. The particles are produced via plasma polymerisation processes of different precursors. The elemental composition of the particles (H and C content) is determined by techniques as NRA and DIGE. NEXAFS measurements give additional information about the chemical structure of the nanoparticles.

We propose a new method for the investigation of plasma crystals. It is equivalent to the X‐ray scattering methods of solid state physics but using far infrared (FIR) laser beams with wavelengths comparable to the Debye length of the system. This method could provide information about structure and dynamics of large 3D plasma crystals. Such crystals with up to 1 million particles have been realised in CCP discharges using micron sized Melamin‐Formaledhyd (MF) particles. We present the setup of the FIR laser system, scattering arrangement, and plasma chamber. Results are discussed including video analysis of plasma crystals and FIR scattering on test samples.

The void formation and its development were traced by the use of a light scattering technique. Additionally, we used a plasma absorption probe to measure the electron density for the voids of different sizes. The results show a difference in electron density inside and outside the void.

International audience; We present experimental and numerical studies of the properties of a capacitively coupled 13.56 MHz discharge in a mixture of Ar and C2H2 with growing nanosize particles. It is found that at the initial stage of the growth, nanoparticles are accumulated near the sheath-plasma boundaries, where the ionization by electrons is maximal. The nanoparticles suppress the ionization due to the absorbing fast electrons and stimulate a quick change of the plasma parameters followed by a transition between different modes of discharge operation. At that moment the peaked distribution of the dust particles transforms into a flat one.

Micro plasmas operated at ambient pressure with dimensions of the confining geometry in the order of a few ten micrometers to a millimeter are actually in the focus of interest due to the broad regime of applicability they offer and due to a similarly broad range of open physical questions. Here we present optical measurements within the discharge core and the effluent region of an especially developed micro discharge jet. To get an understanding of the complex system of this discharge it is important to analyse transport phenomena of energy and particles within both parts of the discharge by various highly sophisticated diagnostics. As a consequence of the limited access and the dimensions of the micro discharge most of these diagnostics are optical. Here we present diagnostics applied to determine spatially resolved absolute atomic oxygen densities as the most reactive constituent of the effluent, density maps of ozone as final reaction product of the gas chemical chain induced by the discharge and phase resolved optical emission spectroscopy yielding insight into the excitation dynamics of the discharge. (C) 2007 WILEY-VCH Verlag GmbH & Co. KGaA. Weinheim.

Carbonaceous compounds are a significant component of interstellar dust and the composition and structure of such materials is therefore of key importance. We present 1.5 μm‐15 μm spectra of a plasma polymerized carbonaceous material produced in RF discharge under low pressure, using C2H2 as a precursor component. The plasma polymerization process described here provides a convenient way to make carbonaceous interstellar dust analogues under controlled conditions and to compare their characteristics to astronomical observations. Here, we focus on a comparison to the IR spectra of interstellar dust in the light of the criteria for “good” carbonaceous interstellar dust analogue. The UV bump at extinction curve 217.5 nm is another key feature for understanding the abundance of carbon in interstellar media. We present here some preliminary results of UV extinction on plasma polymerized astro‐analogue.

Spokes, localised light emission patterns appearing during the HiPIMS discharge, are investigated using optical emission diagnostic and electrical probes. Both, temporal and spatial aspects of the spoke phenomenon have been investigated. The evolution from stochastic to self-organised patterns consisting of a finite number of spokes along the racetrack (= spoke mode number), the transition between two spoke modes, and the stability of a spoke mode is presented. For a constant discharge current, spokes steadily rotate above the magnetron racetrack. The transition between two spoke modes is described by a model which links the spoke mode number decrease with increasing discharge current. It is based on the interaction between the current in the spoke, the Ar rarefaction and Ar replenishment times that prevail over electrostatic repulsion and charged particle diffusion. Two spokes merge by an acceleration of the trailing spoke with respect to the direction of rotation.

Low temperature plasma physics is the driving force of plasma technology which is considered to be one of the key technologies of the 21st century. Due to its central importance to many technologies there is a great demand for highly educated plasma scientists worldwide. Compared to its significance, education in low temperature plasma physics in Germany and other European countries is limited to a relatively small number of universities and institutions. In the last decade research groups located in France, Germany, Ireland, Italy, The Netherlands, Portugal, Switzerland and the United Kingdom have enjoyed fruitful co-operation in founding a series of annual European summer schools with extraordinary success. These schools were organized by Daniel C Schram (Center for Plasma Physics and Radiation Technology (CPS), Eindhoven University of Technology, The Netherlands), Jorg Winter and Marc Boke (both CoE for Plasma Science and Technology (CPST), Ruhr-Universitat Bochum, Germany). The purpose of the schools is to give new graduate students in Europe a solid introduction in and concise overview of low temperature plasma physics and to serve as a forum for providing coherent education in plasma science. The schools have become a part of the curriculum in participating universities. Our experiences have shown that contact between students and teachers forms the basis of enduring interaction. The emphasis has been on fundamental education and the in-depth treatment of subjects such as plasma sources and production, thermal and low pressure plasmas, atomic processes, plasma kinetics, diagnostics, modelling and plasma-surface interactions. After the publication of eight lecture notes as a special section in Plasma Sources Science and Technology volume 9 issue 4 in 2000 we are now able to present four additional notes. Publishing the notes in 2000 was an experiment in itself and we found that the readers of Plasma Sources Science and Technology appreciated this type of presentation. The advantages were twofold: students were introduced to the journal and the content of the lectures could be flexible and change each year. The hope that the journal could profit and increase its readership community has been fulfilled with the great success of the first publication, proven by the huge download rates of most of the notes. However, some aspects could not be treated in the original publication. Now, both compilations serve as an introduction for readers to important subjects in plasma physics. They will be forwarded to the students of the 2007 school and could also serve as an introduction to future schools. The forthcoming schools will be held, as in the past 6 years, at the Physikzentrum Bad Honnef in Germany, organized jointly by the CPS and CPST. We would like to thank all our colleagues for their continuous support and willingness to contribute to the education provided by the schools. Without their contributions and personal engagement the schools would not have been possible. We would also like to thank the following school sponsors: • The European Community • The WE Heraeus Foundation • The Center for Plasma Physics and Radiation Technology (CPS) • The CoE for Plasma Science and Technology (CPST) of Ruhr-Universitat Bochum • Arbeitsgemeinschaft Plasmaphysik APP • Research Training Group GK 1051 • Collaborative Research Centre SFB 591. Finally, we would like to thank the members of the local committees and also the management of the Physikzentrum.

In our work we are focused on study of powder formation in C2H2/Ar plasmas. In this scope we used a combination of FTIR and mass spectroscopy, which are the mostly used experimental techniques for plasma powder formation diagnostics. To test the proposed mechanism for particle nucleation delay we measured the particle nucleation under different plasma conditions: firstly we increased the gas temperature and secondly we changed the background gas from argon to helium., Comment: 12th International Congress on Plasma Physics, 25-29 October 2004, Nice (France)

The axial light distributions in parallel-plate dc microdischarges in argon show similar behavior to large scale discharges. Between the low-current Townsend mode and the high current glow mode exists a large region of currents where different oscillations appear and the dynamic Volt-Ampere characteristic shows hysteresis behavior. During the oscillations the maximum peak intensity moves closer to the cathode, which is characteristic for the abnormal glow regime even though the average current is considerably smaller., Comment: submitted to: IEEE Trans. Plasma Sci., Spec. Issue on Images in Plasma Sci

Space- and time-resolved helium metastable densities (3S1) have been measured in a radio-frequency driven self-pulsing atmospheric pressure microplasma jet (SP μ-APPJ) using tuneable diode laser absorption spectroscopy. Density maps of metastable atoms have been deduced for different times during a self-pulsing cycle with a time resolution of 20 µs, revealing the metastable dynamics in the discharge. The plasma exhibits a bright propagating constricted discharge during every pulse, co-existing with a homogeneous glow-mode (α-mode). The profiles show significantly increased metastable densities over the whole electrode gap in the region of the constricted discharge. In the sheath region, densities reach the order of 1013 cm−3. These densities are three orders of magnitude higher than the densities that were measured in the homogeneous glow-mode. Time-resolved measurements show that the increased metastable density propagates with the constricted discharge from the gas inlet to the nozzle. Between two pulses the metastable density drops down to the level of the glow-mode. Decay times of the metastables in the order of 100 µs have been measured. The propagation velocity of the constricted discharge has been determined from the movement of the metastable maximum.

The behaviour of Cu and Cr HiPIMS (high power impulse magnetron sputtering) discharges was investigated by a combination of optical emission spectroscopy, energy-resolved mass spectrometry and optical imaging, for the complete current–voltage characteristic range achievable within our experimental conditions. Inflection points typical of HiPIMS current–voltage characteristics separate plasma regimes perfectly differentiated in terms of flux composition of species towards the substrate, deposition rate, and the nature of plasma self-organization. The reorganization of the HiPIMS plasma into spokes (areas of high ionization over the target) is associated to one regime of high plasma conductivity, where also deposition rate is limited. This spoke-dominated regime can be substituted by a homogeneous regime at higher powers, where there is an increase of deposition rate, which is driven mostly by an increase in the flux of metal neutrals and metal double-charged ions. The relevance of secondary electron emission mechanisms for the support of the spoke-dominated regime in reactive and non-reactive sputtering conditions is discussed.

Dust will be present in ITER and will be an issue in terms of safety. The ITER strategy for dust management is based among others on the definition and respect of dust inventory limits. To ensure that the safety limits are fulfilled, dust diagnostics and removal techniques need to be developed considering the Tokamak environment constraints (magnetic field, radiation, vacuum and temperature). This paper presents possible dust inventory build-up monitoring strategies for different periods of the machine operation (during/between pulses and during short or long maintenance periods). The strategies rely on the use of a set of complementary techniques for dust diagnostics and removal.

Current–voltage characteristics within the temporal pulse were recorded in high-power pulsed magnetron sputtering discharges for different target materials. These curves allowed identifying at a first glance the existence of separated plasma regimes clearly differentiated by the plasma conductivity and by the spatial arrangement of the plasma emission. We could establish that regimes of high plasma conductivity are univocally associated to the self-organization of the plasma in well-defined ionization zones. As the applied power is gradually increased, the high conductivity regime is abruptly replaced by a regime of high current and low plasma conductivity, associated to homogeneous plasma emission.

The processes of argon retention by the target and redeposition of target material were investigated by x-ray photoelectron spectroscopy as a function of radial position for different plasma conditions in high-power impulse magnetron sputtering of aluminum targets. Significant differences in Ar radial concentration profiles were observed for different discharge conditions. Inside the racetrack area, Ar ion flux-dominated implantation is compensated by radiation-enhanced diffusion loss terms. Outside the racetrack, the role of ion implantation is diminished, and Ar retention by the target may stem from a balance between gettering by redeposited Al and ion-induced Ar desorption.

Al2O3 thin films, either amorphous or of varying degrees of crystallinity, were deposited by two-frequency radio-frequency magnetron sputtering. Film crystallinity was investigated by Fourier transform infrared spectroscopy and X-ray diffraction (XRD). X-ray photoelectron spectroscopy (XPS) was employed to determine the amount of Ar naturally trapped within the films during the deposition process. A clear correlation was found between the existence of crystalline phases, as determined by XRD, and a shift towards lower binding energy positions of the Ar2p core levels of embedded gas. The shift is due to differences in the local Al2O3 matrix (amorphous or crystalline) of the embedded gas, thus, providing an XPS fingerprint that can be used to qualitatively determine the presence or absence of crystalline phases in very thin films.

We report for the first time on instabilities of High Power Impulse Magnetron Sputtering Plasmas (HIPIMS) which are likely to be of the generalised drift wave type. They are characterized by well defined regions of high and low plasma emissivity along the racetrack of the magnetron and causes periodic shifts in floating potential. The azimuthal mode number m depends on plasma current, plasma density, and gas pressure. The structures rotate in

In Ar and He radio-frequency (RF) plasmas with admixtures of C2H2 and CH4 the hydrocarbon chemistry has been studied in relation to dust particle formation by means of infrared tunable diode laser absorption spectroscopy (TDLAS) combined with Fourier transform infrared (FTIR) spectroscopy. The experiments were performed in a RF capacitively coupled parallel plate reactor at a frequency of f = 13.56 MHz, a pressure of p = 0.1 mbar and a flow rate of Φ = 8 sccm of Ar or He with admixtures of 0.5 sccm C2H2 or 1 sccm CH4. The power was P = 15 W. Using TDLAS, the temporal evolution of the concentrations of the methyl radical and of four stable molecules, C2H2, CH4, C2H4 and CO, was monitored in the plasma. Simultaneously, the growth process of the dust particles was analysed by FTIR spectroscopy. The degree of dissociation of the acetylene precursor was found to be nearly constant in the range of 96% under stabilized conditions for both the Ar and He plasmas. In contrast, the degree of dissociation of the methane precursor varied between 45% and 90% depending (i) on the appearance of dust particles in the reactor volume and (ii) on the Ar or He plasma conditions. The methyl radical concentration was found to be in the range of 1011 molecules cm−3. The concentrations of all hydrocarbon species were strongly correlated with the dynamic of the dust formation. Fragmentation efficiencies of acetylene (RF (C2 H2) = 3.2 × 1016 molecules J−1) and of methane (RF (CH4) = (0.16–2.5) × 1016 molecules J−1) and conversion efficiencies to the produced hydrocarbons (RC = (0.23–8.5) × 1014 molecules J−1) could be estimated in dependence on the discharge conditions in the RF plasma.

High power impulse magnetron sputtering (HIPIMS) is a plasma vapour deposition technique used for deposition of dense coatings. In order to contribute to a better understanding of the dynamics of a HIPIMS plasma discharge, time- and wavelength-resolved measurements of the light emitted from the plasma were performed. Lateral images of the HIPIMS plasma were recorded using an ICCD camera with a gate width of 1??s. For each picture, Abel inversion was performed to compute the radial emissivity profile of the plasma. Band-pass interference filters were used to isolate the desired wavelength in order to observe lines of ions and neutrals of metal and argon (Ar) in HIPIMS plasma discharges with an aluminium (Al), titanium (Ti) or chromium (Cr) target in Ar atmosphere. The result is the temporal evolution of the radial emissivity profile of metal and gas neutrals and singly charged ions.

Two different oscillation modes in microdischarge with parallel-plate geometry has been observed: relaxation oscillations with frequency range between 1.23 and 2.1 kHz and free-running oscillations with 7 kHz frequency. The oscillation modes are induced by increasing power supply voltage or discharge current. For a given power supply voltage, there is a spontaneous transition from one to other oscillation mode and vice versa. Before the transition from relaxation to free-running oscillations, the spontaneous increase of oscillation frequency of relaxation oscillations form 1.3 kHz to 2.1 kHz is measured. Fourier Transform Spectra of relaxation oscillations reveal chaotic behaviour of microdischarge. Volt-Ampere characteristics associated with relaxation oscillations describes periodical transition between low current, diffuse discharge and normal glow. However, free-running oscillations appear in subnormal glow only.

We present clear evidence that ground state atomic oxygen shows two patterns near a surface in the helium plasma needle discharge. Two-photon absorption laser-induced fluorescence spectroscopy, combined with gas flow simulation, was employed to obtain spatially-resolved ground state atomic oxygen densities. When the feed gas flow rate is low, the radial density peaks along the axis of the needle. At high flow rate, a ring-shaped density distribution appears. The peak density is on the order of 1021 m−3 in both cases. The results are consistent with a previous report of the flow-dependent bacterial killing pattern observed under similar conditions.

Inside a miniaturized capacitively coupled cold atmospheric pressure plasma jet operated at a helium base gas flow with a minor molecular oxygen admixture atomic oxygen is created. The build up of atomic oxygen along the discharge channel and its further decay in the effluent is investigated by means of xenon calibrated two photon laser induced fluorescence spectroscopy (TALIF). The longitudinal and the transversal atomic oxygen distribution is measured from the discharge core through the transition area into the effluent. A particular emphasis is set on the influence of collisional quenching at elevated pressures.

Plasma enhanced chemical vapor deposition has been used to deposit thin films with gradual transitions from silicon to carbon on Cu, Ni, stainless steel, and NiTi. Thus show low stress, elasticity, and wear resistance with excellent adhesion on all metals under investigation. Already at low Si concentrations of 10 at. % the intrinsic stress is considerably reduced compared to pure diamondlike carbon (DLC) films. The deposition process is controlled by optical emission spectroscopy. This technique has been applied to monitor the growth precursors and to correlate them with the film composition. The compositions of the films were determined by Rutherford backscattering spectroscopy and XPS measurements. Due to the elastic properties of the gradual transition and the excellent biocompatibility of DLC, the described film systems present a useful coating for biomedical applications.

The 19th International Symposium on Plasma Chemistry (ISPC-19) was held at Ruhr-University Bochum, Germany, from 26 to 31 July 2009 under the sponsorship of the International Union of Pure and Applied Chemistry (IUPAC) and the International Plasma Chemistry Society (IPCS), and under the patronage of the Ministry of Innovation, Science, Research and Technology of North-Rhine Westphalia, Germany. Bochum also served as the host venue for ISPC-10 in 1991, and this return occasion of ISPC-19 was co-sponsored by the German Science Foundation, the Ruhr-University Bochum, and the town of Bochum.ISPC is a bi-annual international conference with topics encompassing the complete areas of plasma chemistry and plasma processing science. Almost 650 participants from over 40 countries presented 682 papers. Six plenary speakers and 22 topical invited speakers covered a broad range of topics. These keynote lectures were complemented by 105 oral contributions and about 530 poster presentations in 16 categorized scientific topics. The large number of papers reflects that the current field of plasma chemistry is lively and evolving, and crosses the borders between many disciplines ranging from natural to engineering sciences.This issue of Pure and Applied Chemistry contains 13 papers based on plenary lectures and topical invited talks presented at ISPC-19. This compilation illustrates very well that the traditional distinction between low-pressure and thermal high-pressure plasmas almost disappears; the current research topics on microplasmas and microplasma jets exhibit many similarities if compared to research on conventional arcs used for thermal spraying. We sincerely hope that this issue provides readers an overview of current and future scientific developments.Achim von KeudellConference ChairJörg WinterConference Co-Chair

not Available.

We report on the characterization of single nanoparticles produced in N2–C2H2 low pressure plasmas using scanning near-field infrared microscopy. We use a high power optical parametric oscillator as radiation source, which emits in the so-called fingerprint region 2500–3570 cm−1. We have probed the characteristic N–H absorption band at 3300 cm−1 to characterize single nanoparticles. The observed near-field contrast allows to distinguish between diamond- and polymerlike nanoparticles. Here, the term “diamondlike” refers to hard amorphous carbon material with abundant sp3-coordinated C atoms. Our results demonstrate the feasibility of an infrared spectral characterization of single nanoparticles with nanometer lateral resolution.

The plasma absorption probe is a recently developed tool for efficient determination of electron densities of low temperature plasmas. The occurrence of multiple absorption signals was a serious drawback for interpretation of the probe data. To remedy this drawback, a spherically symmetric design of an absorption probe is proposed. A spherical probe is tested in experiment and simulation and the suppression of the multiple absorption signals is demonstrated. The proof of principle for the concept is given.

The so-called Hannover classification of rejection in cardiac allografts 1 describes degrees of acute rejection with different frequencies of conversion into the forms of rejection that require therapy, where A0, A1, A2, A3, A4, A5a and A5b denote no rejection, mild rejection, mild rejection with premyocytolysis, moderate rejection, severe rejection, early-resolving phase and lateresolving phase, respectively. During episodes of acute rejection, the small coronary vessels frequently show an inflammatory response. The presence of the more severe degrees of concomitant vasculopathy implies an augmented risk of conversion into the form of acute rejection that requires therapy in the resolving and the late-resolving phases. 2 Various and different vasoactive mechanisms are obviously involved in the process of rejection, especially during the acute phase. Mediators of the eicosanoid pathway 3 and of α-adrenergic stimulation 4 might be responsible for episodes of reduction in blood flow. ST-segment depression after transplantation should therefore be expected, especially during active infiltrating processes in the myocardium. Based on these hypotheses, we studied heart transplant recipients using 24-hour ambulatory electrocardiographic recordings to determine the frequency and time of ST-segment depression after heart transplantation in relation to postoperative intervals, and to reveal a possible correlation with active rejection-related processes (acute rejection at various histologic stages).

The coplanar microscale atmospheric pressure plasma jet (μ-APPJ) is a capacitively coupled radio frequency discharge (13.56 MHz, ~15 W rf power) designed for optimized optical diagnostic access. It is operated in a homogeneous glow mode with a noble gas flow (1.4 slm He) containing a small admixture of molecular oxygen (~0.5%). Ground state atomic oxygen densities in the effluent up to 2 × 1014 cm−3 are measured by two-photon absorption laser-induced fluorescence spectroscopy (TALIF) providing space resolved density maps. The quantitative calibration of the TALIF setup is performed by comparative measurements with xenon. A maximum of the atomic oxygen density is observed for 0.6% molecular oxygen admixture. Furthermore, an increase in the rf power up to about 15 W (depending on gas flow and mixture) leads to an increase in the effluent's atomic oxygen density, then reaching a constant level for higher powers.

A bilayer system consisting of carbon and silicon has been developed to coat metals such as copper, stainless steel, nickel, and especially NiTi with an elastic, wear, and corrosion resistant film. The plasma deposited film system exhibits excellent adhesion on all metals under investigation. This adhesion is promoted by silicide formation. Additionally, the film system shows good performance under extremely high load induced via cavitation admission. Tensile tests reveal high elasticity of the film system, in that it can be elongated up to 5% before occurrence of damage of the film. The intrinsic stress inside this film system is reduced compared to pure diamondlike carbon films. Both good chemical bonding and reduced stress lead to good adhesion of the film systems on metals.

The spatial dynamics of the optical emission from an array of 50x50 individual microplasma devices is reported. The array is operated in noble gas at atmospheric pressure with an ac voltage. The optical emission is analyzed with phase and space resolution. It has been found that the emission is not continuous over the entire ac period, it occurs only twice in each cycle. Each of the observed emission phases shows a self-pulsing of the discharge, with several bursts of emission of a fixed width and repetition rate. Cross-talk between the individual devices can be observed through spatially resolved measurements. (C) 2008 American Institute of Physics.

Plasma polymerisation and growth of the dust particles are still in the scope of the plasma community. We analyze the morphology and constitution of plasma polymerized carbonaceous dust particles. The dust particles were grown under different discharge conditions with the different background gas constituents and different monomers. The strong non-equilibrium between electron and ion transport properties causes the charging of the dust in plasma. This, on the other hand, produces changes in the discharge properties, such as: mean electron energy, plasma potential, excitation profiles and sheath dynamics. We report here some of our most relevant results on the properties of complex plasmas.

The plasma absorption probe (PAP) was invented as an economical and robust diagnostic device to determine the electron density distribution in technical plasmas. It consists of a small antenna enclosed by a dielectric tube which is immersed in the plasma. A network analyzer feeds a rf signal to the antenna and displays the frequency dependence of the power absorption. From the absorption spectrum the value of the electron density is calculated. The original evaluation formula was based on the dispersion relation of plasma surface waves propagating along an infinite dielectric cylinder. In this letter the authors present the analysis of a less idealized configuration. The calculated spectra are in good qualitative agreement with their experimental counterparts, but differ considerably from those predicted by the surface wave ansatz. An evaluation scheme which takes our findings into account will improve the performance of the PAP technique further.

We present the Raman spectra of amorphous hydrogenated carbon nanoparticles prepared in an Ar–CH4 hydrocarbon plasma. The measured Raman spectra are compared with that of both soft polymerlike and hard diamondlike a-C:H films deposited from pure CH4 plasma. The film properties were studied by Rutherford backscattering and spectroscopic ellipsometry. It is shown that the plasma characteristics are continuously changed from a “precursor-rich” state to a “precursor” state during the particle formation process. As a result, the net flux of the carbon atoms to the surface of the nanoparticles (growth rate) decreases linearly as a function of time as the nanoparticles are growing up. Also, the hydrogen content in nanoparticles increases as a function of nanoparticle size. The particle growth process is then examined by a simple ballistic model. It is found that the volume polymerization process, i.e., the growth of the nanoparticles at a large particle size (⩾100nm), is essentially the same as the surface polym...

We present the results of time resolved spectroscopy measurements of the Hα line of atomic hydrogen in an Ar-C2H2 radiofrequency plasma. The presence of the fast (high-energy) and slow (low-energy) components of the hydrogen atoms can be deduced from the Doppler broadening of the Hα line. With the appearance of the dust particles, the Hα profile became narrower, indicating reduction of the fast component. We discuss several mechanisms for the formation of the fast hydrogen atoms in our plasma. The main cause for the reduction of the hydrogen atom fast component is the plasma change from electropositive to electronegative, decreasing the sheath's width and voltage. The change of plasma conditions coincides with the end of the dust coagulation/agglomeration when the dust particles become multiply negatively charged. We propose here a new experimental technique for detection of the dust coagulation/agglomeration phase.

Conditioning of the plasma-facing components of fusion devices like inner-wall surfaces and limiters is a necessary prerequisite for the obtention of pure and stable fusion plasmas. Radiofrequency assisted de-glow discharges in various gases (hydrogen, oxygen, methane) are a flexible tool to produce reactive species, which deplete the wall surfaces from reducible oxygen- and carbon-compounds, or allow to plasma-chemically deposit well defined thin layers onto them. The carbonization technique, i.e. the in-situ deposition of amorphous hydrogenated carbon layers (a-C : H) and the resulting effects on tokamak plasmas are discussed in detail. Its application leads to significantly improved plasma performance. After its development and characterization at the Julich tokamak TEXTOR it is now being used worldwide.

Starting from dibenzo-18-crown-6, 1,10-diaza-18-crown-6 and 1,7-diaza-15-crown-5, several crown ether surfactants were synthesized. They all form stable monolayers on water. The methacryloyloxy derivative of 1,10-bis(3-dodecyloxy-2-hydroxypropyl)-1,10-diaza-18-crown-6, 2c, could be polymerized in the monolayer by UV irradiation. This polymerizable crown ether surfactant also forms synthetic vesicles by sonication in water.

In synchronized Euglena gracilis (light-dark regime of 14:10 hours) the successive formation of the photosynthetic apparatus during cell ontogeny is correlated with large changes in photosynthetic efficiency (P Brandt, B von Kessel 1983 Plant Physiol 72: 616-619; B Kohnke, P Brandt 1984 Biochim Biophys Acta 766: 156-160). This observation led us to investigate the functional association of the chlorophyll a/b light-harvesting protein complex (LHCP) with photosystem I or II, because changes in energy flow to photosystem I or II and in energy transfer between the two photosystems can be a reason for these alterations. As criterion for the association of the LHCP with photosystem I or II, state transitions were determined after 15 minutes preillumination using wave-lengths of 725 or 620 nanometers. The state transitions were determined from measurements of fluorescence induction at room temperature, and fluorescence kinetics at 77 K. According to the obtained data (a) mobile LHCP is present only between the 6th and the 10th hour of the light-time of the cell cycle and (b) this functional relation of the LHCP to photosystem I only at this stage of Euglena chloroplast development is not accompanied by a decrease in stacking. A model for the organization of the newly inserted LHCP within the photosynthetic apparatus of E. gracilis is discussed.

Despite enormous potential for technological applications, fundamentals of stable non-equilibrium micro-plasmas at ambient pressure are still only partly understood. Micro-plasma jets are one sub-group of these plasma sources. For an understanding it is particularly important to analyse transport phenomena of energy and particles within and between the core and effluent of the discharge. The complexity of the problem requires the combination and correlation of various highly sophisticated diagnostics yielding different information with an extremely high temporal and spatial resolution. A specially designed rf microscale atmospheric pressure plasma jet (µ-APPJ) provides excellent access for optical diagnostics to the discharge volume and the effluent region. This allows detailed investigations of the discharge dynamics and energy transport mechanisms from the discharge to the effluent. Here we present examples for diagnostics applicable to different regions and combine the results. The diagnostics applied are optical emission spectroscopy (OES) in the visible and ultraviolet and two-photon absorption laser-induced fluorescence spectroscopy. By the latter spatially resolved absolutely calibrated density maps of atomic oxygen have been determined for the effluent. OES yields an insight into energy transport mechanisms from the core into the effluent. The first results of spatially and phase-resolved OES measurements of the discharge dynamics of the core are presented.