@article{1597, abstract = { This study analyzes the acceleration of the arms of a dual system of manipulators that aim to achieve the minimum distance by mimicking the process of approaching spacecraft that are trying to connect. The research was performed simultaneously on a real model and its digital equivalent, in accordance with the Digital Twin (DT) approach. The obtained acceleration values show, for some set sampling times, read out positions and velocities, separate distributed regions of achievable values. The Digital Twin, Digital Shadow (DS) and Digital Model (DM) approaches have recently shown great progress in development, both in academic studies and at industrial level. Along a very wide range of applications, we propose some important issues related to satellite technologies. }, author = {Jędrzejowski, M and Błachowicz, T and Krafczyk, W and Pyka, W and Tokarczyk, O and Chudy, M and Bzymek, A. and Sokół, Z and Ehrmann, Andrea}, issn = {1742-6596}, journal = {Journal of Physics: Conference Series}, number = {1}, publisher = {IOP Publishing}, title = {{Analysis of the quasi-stability of kinematic parameters for manipulators system during the docking process using the Digital Twin approach}}, doi = {10.1088/1742-6596/1950/1/012019}, volume = {1950}, year = {2021}, } @article{1623, abstract = { Square and round magnetic nano-dots of varying dimensions exhibit a large amount of possible magnetization reversal processes, from domain wall nucleation and propagation to multi-vortex states. Clustering such single nano-dots, however, may strongly modify these magnetization reversal processes due to the interactions between neighboring particles. Here we thus investigate the difference between magnetization reversal processes in clusters of hexagonally arranged round nano-dots under different orientations of the external magnetic field in comparison with single particle behavior.}, author = {Blachowicz, T and Ehrmann, Andrea}, issn = {1742-6596}, journal = {Journal of Physics: Conference Series}, number = {1}, publisher = {IOP Publishing}, title = {{Influence of clustering round magnetic nano-dots on magnetization reversal}}, doi = {10.1088/1742-6596/1730/1/012034}, volume = {1730}, year = {2021}, } @article{3516, abstract = {Silicon-wafer based solar cells are still domination the market for photovoltaic energy conversion. However, most of the silicon is used only for mechanical stability, while only a small percentage of the material is needed for the light absorption. Thin film silicon technology reduces the material demand to just some hundred nanometer thickness. But even in a tandem stack (amorphous and microcrystalline silicon) the efficiencies are lower, and light-induced degradation is an important issue. The established standard tests for characterisation are not precise enough to predict the performance of thin film silicon solar cells under real conditions, since many factors do have an influence on the degradation. We will show some results of laboratory and outdoor measurements that we are going to use as a base for advanced modelling and simulation methods.}, author = {Hamelmann, Frank and Weicht, J A and Behrens, Grit}, issn = {1742-6596}, journal = {Journal of Physics: Conference Series}, publisher = {IOP Publishing}, title = {{Light-Induced Degradation of Thin Film Silicon Solar Cells}}, doi = {10.1088/1742-6596/682/1/012002}, volume = {682}, year = {2016}, } @article{3515, abstract = {Silicon-based thin film tandem solar cells consist of one amorphous (a-Si) and one microcrystalline (μc-Si) silicon solar cell. The Staebler - Wronski effect describes the light- induced degradation and temperature-dependent healing of defects of silicon-based solar thin film cells. The solar cell degradation depends strongly on operation temperature. Until now, only the light-induced degradation (LID) of the amorphous layer was examined in a-Si/μc-Si solar cells. The LID is also observed in pc-Si single function solar cells. In our work we show the influence of the light-induced degradation of the μc-Si layer on the diode equivalent circuit. The current-voltage-curves (I-V-curves) for the initial state of a-Si/pc-Si modules are measured. Afterwards the cells are degraded under controlled conditions at constant temperature and constant irradiation. At fixed times the modules are measured at standard test conditions (STC) (AM1.5, 25°C cell temperature, 1000 W/m2) for controlling the status of LID. After the degradation the modules are annealed at dark conditions for several hours at 120°C. After the annealing the dangling bonds in the amorphous layer are healed, while the degradation of the pc-Si is still present, because the healing of defects in pc-Si solar cells needs longer time or higher temperatures. The solar cells are measured again at STC. With this laboratory measured I-V-curves we are able to separate the values of the diode model: series Rs and parallel resistance Rp, saturation current Is and diode factor n.}, author = {Weicht, J A and Hamelmann, Frank and Behrens, Grit}, issn = {1742-6596}, journal = {Journal of Physics: Conference Series}, publisher = {IOP Publishing}, title = {{Simulation of light-induced degradation of μc-Si in a-Si/μc-Si tandem solar cells by the diode equivalent circuit}}, doi = {10.1088/1742-6596/682/1/012017}, volume = {682}, year = {2016}, } @article{3512, abstract = {Zinc oxide is known as a mineral since 1810, but it came to scientific interest after its optoelectronic properties found to be tuneable by p-type doping. Since the late 1980's the number of publications increased exponentially. All thin film deposition technologies, including sol-gel and spray pyrolysis, are able to produce ZnO films. However, for outstanding properties and specific doping, only chemical vapor deposition and physical vapor deposition have shown so far satisfying results in terms of high conductivity and high transparency. In this paper the different possibilities for doping will be discussed, some important applications of doped ZnO thin films will be presented. The deposition technologies used for industrial applications are shown in this paper. Especially sputtering of aluminium doped Zinc Oxide (ZnO:Al or AZO) and LPCVD of boron doped Zinc Oxide (ZnO:B or BZO) are used for the commercial production of transparent conductive oxide films on glass used for thin film photovoltaic cells. For this special application the typical process development for large area deposition is presented, with the important trade-off between optical properties (transparency and ability for light scattering) and electrical properties (conductivity). Also, the long term stability of doped ZnO films is important for applications, humidity in the ambient is often the reason for degradation of the films. The differences between the mentioned materials are presented.}, author = {Hamelmann, Frank}, issn = {1742-6596}, journal = {Journal of Physics: Conference Series}, publisher = {IOP Publishing}, title = {{Thin film zinc oxide deposited by CVD and PVD}}, doi = {10.1088/1742-6596/764/1/012001}, volume = {764}, year = {2016}, } @article{3521, abstract = {This paper show results from the development of transparent conductive oxides (TCO's) on large areas for the use as front electrode in thin film silicon solar modules. It is focused on two types of zinc oxide, which are cheap to produce and scalable to a substrate size up to 6 m2. Low pressure CVD with temperatures below 200°C can be used for the deposition of boron doped ZnO with a native surface texture for good light scattering, while sputtered aluminum doped ZnO needs a post deposition treatment in an acid bath for a rough surface. The paper presents optical and electrical characterization of large area samples, and also results about long term stability of the ZnO samples with respect to the so called TCO corrosion.}, author = {Hamelmann, Frank}, issn = {1742-6596}, journal = {Journal of Physics: Conference Series}, publisher = {IOP Publishing}, title = {{Transparent Conductive Oxides in Thin Film Photovoltaics}}, doi = {10.1088/1742-6596/559/1/012016}, volume = {559}, year = {2014}, } @article{3563, abstract = {For analyzing the long-term behavior of thin film a-Si/μc-Si photovoltaic modules, it is important to observe the light-induced degradation (LID) in dependence of the temperature for the parameters of the one-diode model for solar cells. According to the IEC 61646 standard, the impact of LID on module parameters of these thin film cells is determined at a constant temperature of 50°C with an irradiation of 1000 W/m2 at open circuit conditions. Previous papers examined the LID of thin film a-Si cells with different temperatures and some others are about a-Si/μc-Si. In these previous papers not all parameters of the one-diode model are examined. We observed the serial resistance (Rs), parallel resistance (Rp), short circuit current (Isc), open circuit voltage (Uoc), the maximum power point (MPP: Umpp, Impp and Pmpp) and the diode factor (n). Since the main reason for the LID of silicon-based thin films is the Staebler Wronski effect in the a-Si part of the cell, the temperature dependence of the healing of defects for all parameters of the one-diode model is also taken into account. We are also measuring modules with different kind of transparent conductive oxides: In a-Si thin film solar cells fluorine-doped tin oxide (FTO) is used and for thin film solar cells of a-Si/μc-Si boron- doped zinc oxide is used. In our work we describe an approach for transferring the parameters of a one-diode model for tandem thin film solar cells into the one-diode model for each part of the solar cell. The measurement of degradation and regeneration at higher temperatures is the necessary base for optimization of the different silicon-based thin films in warm hot climate.}, author = {Weicht, J A and Hamelmann, Frank and Behrens, G}, issn = {1742-6596}, journal = {Journal of Physics: Conference Series}, publisher = {IOP Publishing}, title = {{Parameter variation of the one-diode model of a-Si and a- Si/μc-Si solar cells for modeling light-induced degradation}}, doi = {10.1088/1742-6596/559/1/012017}, volume = {559}, year = {2014}, }