Microwave plasma-based direct synthesis of free-standing N-graphene

Scheme of ethanol/ammonia plasma driven decomposition pathways considering injection of the nitrogen precursor in “hot” and “mild” plasma zone.

Enhancement of conductivity in nano carbon balls by the addition of carbon tetrachloride via room temperature solution plasma process

(a) Reaction field in solution plasma zone and dehydrogenation by Cl radicals, (b) enhancement of conductivity of nanocarbon sphere by the addition of CCl4 within benzene.

Spectral evolution of the galactic microquasars XTE J1550-564 and GRO J1655-40 during outbursts

We present results of a broadband spectroscopy of the galactic microquasars and black hole candidates XTE J1550-564 and GRO J1655-40, performed with the INTEGRAL and RXTE observatories during strong outbursts in 2003 and 2005, respectively. The spectral parameters evolution was traced during brightening and fading phases of each outburst to search a possible hysteresis and transitions from state to state. We estimated a size and optical depth of different regions around XTE J1550-564, like a hot plasma zone and optically thick accretion disk. Upper limits to the annihilation 511 keV line emission were obtained for both sources using data of the SPI spectrometer onboard the INTEGRAL observatory.

Design of a Novel Corona Plasma Reactor for Decomposition of VOCs

The configuration of discharge electrode is closely related to the uniformity and the strength of corona plasma, which has big effect on the efficiency of plasma in destructing pollutants, treating materials and so on. A novel sheet electrode was devised to enhance the input energy and the uniformity of plasma’s distribution, and its production performance of plasma was compared with other discharge electrodes including wire, needle and multi-needles. Corona images and I-V characteristic curves of discharge electrodes indicate that ultra-thin sheet electrode could produce more uniform and stronger corona plasma zone than other electrodes in this paper, which is advantageous for decomposing pollutants, treating material surface and so on. Primary VOCs decomposition experiments were conducted, and the results indicated that the highest energy yield of VOCs decomposition reached 1.8 g (benzene) • (kWh)-1 /3.5 g (toluene) • (kWh)-1.

Effect of Plasma Gas Flow Direction on Hydrophilicity of Polymer by Small Zone Cold Plasma Treatment and Hydrophobic Plasma Treatment

Plasma treatment is the most popular surface modification process of polymers. A small cold plasma zone treatment is an important modification technique in modern industry. In this study, the effect of gas flow direction on plasma treatment was investigated. In order to decrease the plasma zone area, we added a separate cylinder to surround the upper electrode. The separate cylinder is effective in limiting the plasma discharge area, and we could find a light and dark area in the vacuum chamber. After O2 plasma treatment, the result shows that only PP nonwoven in the discharge area became hydrophilic, but the other position away from the plasma zone was not affected. The water adsorption of PP nonwoven increased from 34.8% to 537.4%. When the sample is further from the plasma zone, near the up stream of gas flow, the surface property is less hydrophilic. The water contact angle analysis of PS and glass shows the same results as those of PP nonwoven. But PET in plasma zone or dark zone (plasma zone: 75° to 31°, dark zone: 75° to 52°) both show hydrophilic property. The wettability effect in the dark zone may be due to the UV-light irradiation in the process of plasma excitation.

Macroscopic control of plasma polymerization processes

Plasma polymerization covers a broad range of plasma deposits from soft to hard coatings. Nanoscale coatings are formed within a dry and eco-friendly process on different substrate materials and structures. To gain a deeper insight into plasma polymerization, a macroscopic approach using the concept of chemical quasi-equilibria might be useful. Following this macroscopic approach, the reaction parameter power input per gas flow W/F, which represents the specific energy invested per particle within the active plasma zone, solely determines the mass deposition rate. Hence, plasma polymerization can be described by measuring the deposited mass and examining the power input and gas flow which contributes to it. Thus, the control, investigation, and up-scaling of plasma polymerization processes are enabled. Different examples are given to make use of the macroscopic approach.