Fraunhofer-Publica
The Fraunhofer-Publica has been successfully documenting the research results of the Fraunhofer-Gesellschaft for over 30 years. The platform enables the collaborative linking of research-relevant objects and disseminates within the international scientific community.
The Fraunhofer-Publica thus fulfils its responsibility to promote the transfer of knowledge and know-how to industry and society.
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Research outputs
As an application-oriented research organisation, Fraunhofer aims to conduct highly innovative and solution-oriented research - for the benefit of society and to strengthen the German and European economy.
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Projects
Fraunhofer is tackling the current challenges facing industry head on. By pooling their expertise and involving industrial partners at an early stage, the Fraunhofer Institutes involved in the projects aim to turn original scientific ideas into marketable products as quickly as possible.
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Researchers
Scientific achievement and practical relevance are not opposites - at Fraunhofer they are mutually dependent. Thanks to the close organisational links between Fraunhofer Institutes and universities, science at Fraunhofer is conducted at an internationally first-class level.
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Institutes
The Fraunhofer-Gesellschaft is the leading organisation for applied research in Europe. Institutes and research facilities work under its umbrella at various locations throughout Germany.
Recent Additions
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PublicationAdaptive Wärmepumpenregelung mit KI( 2024)
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PublicationStructure and Validation of a Kinematic Surface Simulation Model for the Direct Laser Writing Process( 2024)The article introduces the structure and validation of a kinematic surface simulation model for the replication of laser‐structured surfaces and their impressions after hot embossing. The surface replication is accomplished by the stepwise Boolean intersection of a structured and digitized point ablation with the workpiece. The resulting surface is characterized according to ISO 25178. Resulting from the kinematic simulation principle, the model can be applied to a wide range of material-machine combinations in the field of laser structuring and enables a time-efficient, nanometer‐resolved replication of representative surfaces with a size up to several square millimeters. Within the validation process it was proven that the main surface characteristics can be predicted by the model. Compared to AI approaches and numerical or multiphysical simulations, preliminary studies are only needed to a very small extent. Furthermore, complex influences such as material and temperature‐related properties do not need separate consideration as they are taken into account by the digitized point ablation.
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PublicationChloromonas fuhrii sp. nov. (Chlorophyceae), a cosmopolitan alga from colored snow( 2024-02-20)The modern concept of the genus Chloromonas includes a subclade of species found exclusively in snow. We describe Chloromonas (Cr.) fuhrii sp. nov., a new member of this clade, which is closely related to Cr. muramotoi from Japan. The new species is characterised by the absence of a stigma, pyrenoid, and defined papilla, ready loss of flagella in culture, and a single lobed chloroplast. Strains of Cr. fuhrii have been sourced from green, orange, and pink/red snow. The species has been found in Svalbard, Antarctica, and New Zealand, with most genetic variation occurring in Svalbard. The minimal variation present in New Zealand strains suggests a relatively recent arrival. Secondary structure models for ITS2 in the new species demonstrate a separation from Cr. muramotoi due to one CBC. The nine New Zealand strains isolated showed no variation in ITS2 but four variable base positions in ITS1. Inclusion of the single Antarctic and four Svalbard strains resulted in 14 variable positions in ITS2 and 69 in ITS1, with the sequences remaining alignable. The ITS data showed a strong biogeographic signal, both in total in an unrooted tree, and using ITS2 alone with Cr. muramotoi as an outgroup. The absence of a stigma in this species prompted a survey of the literature, showing that stigma absence in Chloromonas is strongly associated with the snow habitat, occurring at about 10 times the rate observed in other habitats, perhaps owing to the difficulty of phototaxis in snow with abundant reflected light.
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PublicationInfluence of Screw Design and Process Parameters on the Product Quality of PEO:LiTFSI Solid Electrolytes Using Solvent-Free Melt Extrusion( 2024-05-28)All-solid-state battery (ASSB) technology is a new energy system that reduces the safety concerns and improves the battery performance of conventional lithium-ion batteries (LIB). The increasing demand for such new energy systems makes the transition from laboratory scale production of ASSB components to larger scale essential. Therefore, this study investigates the dry extrusion of poly(ethylene oxide):lithium bis (trifluoromethylsulfonyl)imide (PEO:LiTFSI) all-solid-state electrolytes at a ratio of 20:1 (EO:Li). We investigated the influence of different extruder setups on the product quality. For this purpose, different screw designs consisting of conveying, kneading and mixing elements are evaluated. To do so, a completely dry and solvent-free production of PEO:LiTFSI electrolytes using a co-rotating, intermeshing, twin-screw extruder under an inert condition was successfully carried out. The experiments showed that the screw design consisting of kneading elements gives the best results in terms of process stability and homogeneous mixing of the electrolyte components. Electrochemical impedance spectroscopy was used to determine the lithium-ion conductivity. All electrolytes produced had an ionic conductivity (σionic) of (1.1-1.8) × 10-4 S cm-1 at 80 °C.
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PublicationQualitative evaluation of flip chip solder bumps produced by stencil printing of solder paste on various electroless nickel/gold metallizations( 2006)Stencil printing of solder paste in conjunction with electroless Ni/Au UBM on Al metallization offers the most economical method for wafer bumping either for Flip chip applications or for WLCSP packages. This paper deals in detail with the bumping process of 6? wafers at 300µm and 200µm pitch and investigates the bump interface integrity for different Au flash thicknesses on 5µm Ni. The bump height produced is 108±5µm with Sn63Pb37 and Sn4Ag0.5Cu compositions. Bumped chips have undergone high temperature storage at 150oC and up to 10 multiple reflow passes. Interesting results show that the shear strength of bumps with 5µmNi/26nmAu/Sn4Ag0.5Cu interface is about 97.1±8.3 MPa; very close to the standard 5µmNi/80nmAu UBM used so far in electroless processes. Furthermore, Sn4Ag0.5Cu bumps with only 5µm Ni UBM (without flash Au) has shown significant shear strength of about 80.4 ± 8.9 MPa which corresponds to about 17% reduction in strength. The prevailing shear fracture mode for all bumped chips is solder bulk fracture. The results imply that a possible reduction in Au flash thickness or a complete absence of Au can be potentially applied without any compromise in the mechanical integrity and robustness of the bumps.
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PublicationAlgorithm for the Automatic Verification of Complex Mixed-Signal ICs regarding ESD-Stress( 2005)In this publication, an algorithm is described which automates the verification of a com¬p¬lex integrated circuit (IC) with regard to the behavior under transient high voltage impulses (e.g. ESD). Here, the complexity of the whole circuit diagram is being reduced in a first step in order to carry out a transient simulation with high current simulation models time-efficiently in a second step. The nowadays usual manual extraction of the relevant circuit parts for such a transient analysis is then automated and therefore, the error susceptibility of this process is minimized as well. The algorithm is embedded in a commercial design frame¬work for IC-design and uses the data structures already existing.