@article{HoffmannUhlCeblinetal.2022,
  author    = {Hoffmann, Andreas and Uhl, Matthias and Ceblin, Maximilian and Rohrbach, Felix and Bansmann, Joachim and Mallah, Marcel and Heuermann, Holger and Jacob, Timo and Kuehne, Alexander J.C.},
  title     = {Atmospheric pressure plasma-jet treatment of PAN-nonwovens—carbonization of nanofiber electrodes},
  series = {C - Journal of Carbon Research},
  volume    = {8},
  journal   = {C - Journal of Carbon Research},
  number    = {3},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2311-5629},
  doi       = {10.3390/c8030033},
  pages     = {8 Seiten},
  year      = {2022},
  abstract  = {Carbon nanofibers are produced from dielectric polymer precursors such as polyacrylonitrile (PAN). Carbonized nanofiber nonwovens show high surface area and good electrical conductivity, rendering these fiber materials interesting for application as electrodes in batteries, fuel cells, and supercapacitors. However, thermal processing is slow and costly, which is why new processing techniques have been explored for carbon fiber tows. Alternatives for the conversion of PAN-precursors into carbon fiber nonwovens are scarce. Here, we utilize an atmospheric pressure plasma jet to conduct carbonization of stabilized PAN nanofiber nonwovens. We explore the influence of various processing parameters on the conductivity and degree of carbonization of the converted nanofiber material. The precursor fibers are converted by plasma-jet treatment to carbon fiber nonwovens within seconds, by which they develop a rough surface making subsequent surface activation processes obsolete. The resulting carbon nanofiber nonwovens are applied as supercapacitor electrodes and examined by cyclic voltammetry and impedance spectroscopy. Nonwovens that are carbonized within 60 s show capacitances of up to 5 F g⁻¹.},
  language  = {en}
}
@article{HoffmannRohrbachUhletal.2022,
  author    = {Hoffmann, Andreas and Rohrbach, Felix and Uhl, Matthias and Ceblin, Maximilian and Bauer, Thomas and Mallah, Marcel and Jacob, Timo and Heuermann, Holger and Kuehne, Alexander J. C.},
  title     = {Atmospheric pressure plasma-jet treatment of polyacrylonitrile-nonwovens—Stabilization and roll-to-roll processing},
  series = {Journal of Applied Polymer Science},
  volume    = {139},
  journal   = {Journal of Applied Polymer Science},
  number    = {37},
  publisher = {Wiley},
  issn      = {0021-8995 (Print)},
  doi       = {10.1002/app.52887},
  pages     = {1 -- 9},
  year      = {2022},
  abstract  = {Carbon nanofiber nonwovens represent a powerful class of materials with prospective application in filtration technology or as electrodes with high surface area in batteries, fuel cells, and supercapacitors. While new precursor-to-carbon conversion processes have been explored to overcome productivity restrictions for carbon fiber tows, alternatives for the two-step thermal conversion of polyacrylonitrile precursors into carbon fiber nonwovens are absent. In this work, we develop a continuous roll-to-roll stabilization process using an atmospheric pressure microwave plasma jet. We explore the influence of various plasma-jet parameters on the morphology of the nonwoven and compare the stabilized nonwoven to thermally stabilized samples using scanning electron microscopy, differential scanning calorimetry, and infrared spectroscopy. We show that stabilization with a non-equilibrium plasma-jet can be twice as productive as the conventional thermal stabilization in a convection furnace, while producing electrodes of comparable electrochemical performance.},
  language  = {en}
}
@article{HeuermannEmmrichBongartz2022,
  author    = {Heuermann, Holger and Emmrich, Thomas and Bongartz, Simon},
  title     = {Microwave spark plug to support ignitions with high compression ratios},
  series = {IEEE Transactions on Plasma Science},
  journal   = {IEEE Transactions on Plasma Science},
  number    = {Early Access},
  publisher = {IEEE},
  issn      = {1939-9375},
  doi       = {10.1109/TPS.2022.3183690},
  pages     = {1 -- 6},
  year      = {2022},
  abstract  = {Upcoming gasoline engines should run with a larger number of fuels beginning from petrol over methanol up to gas by a wide range of compression ratios and a homogeneous charge. In this article, the microwave (MW) spark plug, based on a high-speed frequency hopping system, is introduced as a solution, which can support a nitrogen compression ratio up to 1:39 in a chamber and more. First, an overview of the high-speed frequency hopping MW ignition and operation system as well as the large number of applications are presented. Both gives an understanding of this new base technology for MW plasma generation. Focus of the theoretical part is the explanation of the internal construction of the spark plug, on the achievable of the high voltage generation as well as the high efficiency to hold the plasma. In detail, the development process starting with circuit simulations and ending with the numerical multiphysics field simulations is described. The concept is evaluated with a reference prototype covering the frequency range between 2.40 and 2.48 GHz and working over a large power range from 20 to 200 W. A larger number of different measurements starting by vector hot-S11 measurements and ending by combined working scenarios out of hot temperature, high pressure and charge motion are winding up the article. The limits for the successful pressure tests were given by the pressure chamber. Pressures ranged from 1 to 39 bar and charge motion up to 25 m/s as well as temperatures from 30◦ to 125◦.},
  language  = {en}
}
@inproceedings{AllalBannisterBuismanetal.2022,
  author    = {Allal, D. and Bannister, R. and Buisman, K. and Capriglione, D. and Di Capua, G. and Garc{\´i}a-Patr{\´o}n, M. and Gatzweiler, Thomas and Gellersen, F. and Harzheim, Thomas and Heuermann, Holger and Hoffmann, J. and Izbrodin, A. and Kuhlmann, K. and Lahbacha, K. and Maffucci, A. and Miele, G. and Mubarak, F. and Salter, M. and Pham, T.D. and Sayegh, A. and Singh, D. and Stein, F. and Zeier, M.},
  title     = {RF measurements for future communication applications: an overview},
  series = {2022 IEEE International Symposium on Measurements \& Networking (M\&N)},
  booktitle = {2022 IEEE International Symposium on Measurements \& Networking (M\&N)},
  publisher = {IEEE},
  isbn      = {978-1-6654-8362-9},
  issn      = {2639-5061},
  doi       = {10.1109/MN55117.2022.9887740},
  pages     = {1 -- 6},
  year      = {2022},
  abstract  = {In this paper research activities developed within the FutureCom project are presented. The project, funded by the European Metrology Programme for Innovation and Research (EMPIR), aims at evaluating and characterizing: (i) active devices, (ii) signal- and power integrity of field programmable gate array (FPGA) circuits, (iii) operational performance of electronic circuits in real-world and harsh environments (e.g. below and above ambient temperatures and at different levels of humidity), (iv) passive inter-modulation (PIM) in communication systems considering different values of temperature and humidity corresponding to the typical operating conditions that we can experience in real-world scenarios. An overview of the FutureCom project is provided here, then the research activities are described.},
  language  = {en}
}