TY - JOUR A1 - Hampe, Andreas A1 - Kalinka, Gerhard A1 - Meretz, S. A1 - Schulz, Eckhard T1 - An advanced equipment for single-fibre pull-out test designed to monitor the fracture process KW - Verbundwerkstoffe KW - Thermoplaste KW - Adhäsion KW - Reibung KW - Haftung KW - Interface KW - Schubfestigkeit KW - Scherfestigkeit KW - Messmethode PY - 1995 SN - 0010-4361 VL - 26 IS - 1 SP - 40 EP - 46 PB - Butterworth-Heinemann CY - Guildford, Surrey AN - OPUS4-11988 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schulz, Eckhard A1 - Kalinka, Gerhard A1 - Meretz, S. A1 - Hampe, Andreas T1 - Pull-out of Single Fibres KW - Verstärkungsfaser KW - Verbundwerkstoffe KW - Interface KW - Adhäsion KW - Reibung KW - Haftung KW - Thermoplast PY - 1994 SN - 0945-0084 VL - 84 IS - 5 SP - 25 EP - 26 PB - Hanser CY - München AN - OPUS4-11989 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schulz, Eckhard A1 - Kalinka, Gerhard A1 - Meretz, S. A1 - Hampe, Andreas T1 - Einzelfaserauszug - Eine Methode zum Bestimmen der Grenzflächenfestigkeit KW - Verstärkungsfaser KW - Verbundwerkstoffe KW - Interface KW - Adhäsion KW - Reibung KW - Haftung KW - Thermoplast PY - 1994 SN - 0023-5563 VL - 84 IS - 5 SP - 608 EP - 610 PB - Hanser CY - München AN - OPUS4-11994 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ho, K.K.C. A1 - Lamoriniere, S. A1 - Kalinka, Gerhard A1 - Schulz, Eckhard A1 - Bismarck, A. T1 - Interfacial behavior between atmospheric-plasma-fluorinated carbon fibers and poly(vinylidene fluoride) N2 - Atmospheric-plasma fluorination was used to introduce fluorine functionalities onto the surface of carbon fibers without affecting their bulk properties. The interfacial adhesion between atmospheric-plasma-fluorinated carbon fibers and poly(vinylidene fluoride) (PVDF) was studied by means of direct wetting measurements and single fiber pullout tests. Measured contact angles of PVDF melt droplets on modified carbon fibers show that short exposure times of carbon fibers to atmospheric-plasma fluorination (corresponding to a degree of surface fluorination of F/C = 0.01 (1.1%)) leads to improved wettability of the fibers by PVDF melts. The apparent interfacial shear strength as a measure of practical adhesion, determined by the single-fiber pullout test, increases by 65% under optimal treatment conditions. The improved practical adhesion is not due to the formation of transcrystalline regions around the fibers or a change of the bulk matrix crystallinity or to an increased surface roughness; it seems to be due to the compatibilization of the interface caused of the atmospheric-plasma fluorination of the carbon fibers. KW - Carbon fibers KW - Fluorination KW - Contact angle KW - Interface KW - Adhesion KW - Surface area KW - Fiber properties PY - 2007 DO - https://doi.org/10.1016/j.jcis.2007.04.076 SN - 0021-9797 SN - 1095-7103 VL - 313 IS - 2 SP - 476 EP - 484 PB - Elsevier CY - Orlando, Fla. AN - OPUS4-16026 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Baytekin, H.T. A1 - Baytekin, B. A1 - Schulz, a. A1 - Springer, A. A1 - Gross, Thomas A1 - Unger, Wolfgang A1 - Artamonova, M. A1 - Schlecht, S. A1 - Lentz, D. A1 - Schalley, C.A. T1 - Metallo-supramolecular nanospheres via hierarchical self-assembly N2 - A novel coordination oligo/polymer is synthesized by metal-directed self-assembly from equimolar amounts of the (dppp)M(OTf)2 precursor complexes (dppp = bis-(diphenylphosphino)-propane, OTf = triflate; M = PdII or M = PtII) and banana-shaped bidentate dipyridyl ligands. The assemblies were characterized by ESI mass spectrometry and NMR spectroscopy. The analysis of the cloudy suspension prepared by dissolving the coordination polymer in aqueous methanol solutions indicates nanosized spherical objects to form. Evidence for vesicle formation from these metallo-supramolecular oligomers comes from (cryogenic) transmission electron microscopy (TEM, cryo-TEM). Atomic force microscopy revealed stable nanospheres on hydrophilic mica and monolayer formation on hydrophobic highly oriented pyrolitic graphite (HOPG) substrates. On mica, also torus-shaped object were observed, which are rationalized by vesicles that opened during the drying procedure and released the internal solvent. Elemental analysis of the nanoassemblies by X-ray photoelectron spectroscopy (XPS) indicates uncoordinated and coordinated pyridines in the coordination polymers that form the nanospheres. Various control experiments using different metal centers and modified ligands support the conclusions. KW - Self-assembly KW - Metallo-supramolecular chemistry KW - Coordination polymers KW - Vesicles KW - Electron microscopy KW - Nano-materials PY - 2009 DO - https://doi.org/10.1021/cm900642p SN - 0897-4756 SN - 1520-5002 VL - 21 IS - 13 SP - 2980 EP - 2992 PB - American Chemical Society CY - Washington, DC AN - OPUS4-19638 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Frunza, S. A1 - Schönhals, Andreas A1 - Frunza, L. A1 - Ganea, P. A1 - Kosslick, H. A1 - Harloff, J. A1 - Schulz, A. T1 - Molecular relaxation processes in a MOF-5 structure revealed by broadband dielectric spectroscopy: signature of phenylene ring fluctuations N2 - The molecular mobility of a MOF-5 metal–organic framework was investigated by broadband dielectric spectroscopy. Three relaxation processes were revealed. The temperature dependence of their relaxation rates follows an Arrhenius law. The process observed at lower temperatures is attributed to bending fluctuations of the edges of the cages involving the Zn–O clusters. The processes ('region II') at higher temperatures were assigned to fluctuations of phenyl rings in agreement with the NMR data found by Gould et al. (J. Am. Chem. Soc. 2008, 130, 3246). The carboxylate groups might also be involved. The rotational fluctuations of the phenyl rings leading to the low frequency part of relaxation region II might be hindered either by some solvent molecules entrapped in the cages or by an interpenetrated structure and have a broad distribution of activation energies. The high frequency part of region II corresponds nearly to a Debye-like process: This is explained by a well-defined structure of empty pores. PY - 2010 DO - https://doi.org/10.1021/jp1071617 SN - 1520-6106 SN - 1520-5207 SN - 1089-5647 VL - 114 IS - 40 SP - 12840 EP - 12846 PB - Soc. CY - Washington, DC AN - OPUS4-22255 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lüth, Peter A1 - Brandes, E. A1 - Frost, K. A1 - Kurth, Lutz A1 - Schmidt, Martin A1 - Michael-Schulz, Heike A1 - Uhlig, S. T1 - CEQAT-DGHS Ringversuchsprogramm für die Chemikaliensicherheit -Methodenvalidierung N2 - Bei der Bewertung der Verlässlichkeit der im Labor gewonnenen Prüfergebnisse spielen Ringversuche eine entscheidende Rolle. Die Bundesanstalt für Materialforschung und –prüfung (BAM) unterstützt deshalb den weiteren Ausbau des Ringversuchsprogramms des im Jahr 2007 gegründeten Kompetenzzentrums zur Qualitätssicherung für Prüfungen von Gefahrgütern und Gefahrstoffen auf physikalische Gefahren (Centre for quality assurance for testing of dangerous goods and hazardous substances, CEQAT-DGHS). Bei allen bisher untersuchten Prüfmethoden besteht ein Verbesserungsbedarf. Die RV müssen daher zunächst auf die Methodenentwicklung, -verbesserung und -validierung und auf die Bestimmung der Messunsicherheit der jeweiligen Prüfmethode abzielen und nicht auf Leistungstests. T2 - Behörden-Erfahungsaustausch CY - Berlin, Germany DA - 4. Juni 2018 KW - Prüfmethode KW - Methodenvalidierung KW - Gefahrgut KW - Gefahrstoff KW - Qualitätssicherung PY - 2018 AN - OPUS4-45297 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jost, M. A1 - Strunck, S. A1 - Heunisch, Andreas A1 - Wiens, A. A1 - Prasetiadi, A.E. A1 - Weickhmann, C. A1 - Schulz, Bärbel A1 - Quibeldey, M. A1 - Karabey, O.H. A1 - Rabe, Torsten A1 - Follmann, R. A1 - Koether, D. A1 - Jakoby, R. T1 - Continuously tuneable liquid crystal based stripline phase shifter realised in LTCC technology N2 - This work presents the design, fabrication and measurements of a low temperature cofired ceramic (LTCC) integrated liquid crystal (LC) phase shifter. The effective permittivity of the phase shifter and therefore its differential phase shift can be tuned continuously by orienting the LC directors with electric fields. The phase-shift demonstrator is designed for Ka-band frequencies around 30 GHz and represents a stripline filled with LC, embedded inside an LTCC multilayer structure, which provides a space-qualified and hermetically-sealed LC cavity within an RF-capable material system. The total length of the device is 37 mm while the phase shifting LC section has a length of 14.6 mm. At 30 GHz it exhibits a differential phase shift of 60° with an insertion loss around 6 dB, resulting in a figure of merit around 10°/dB. An advantage is that the insertion loss is nearly independent of the tuning state of the LC. The response time of the phase shifter, depending on the desired LC orientation, is between 62 ms and 37 s. T2 - EuMC 2015 - 45th European microwave conference CY - Paris, France DA - 07.09.2015 PY - 2015 SN - 978-2-87487-039-2 SP - 1260 EP - 1263 AN - OPUS4-35268 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Strunck, S. A1 - Gaebler, A. A1 - Karabey, O.H. A1 - Heunisch, Andreas A1 - Schulz, Bärbel A1 - Rabe, Torsten A1 - Follmann, R. A1 - Kassner, J. A1 - Koether, D. A1 - Manabe, A. A1 - Jakoby, R. T1 - Reliability study of a tunable ka-band SIW-phase shifter based on liquid crystal in LTCC-technology N2 - A tunable substrate-integrated waveguide phase shifter using low-temperature co-fired ceramic (LTCC)-technology is presented in this paper. By changing the effective permittivity in the liquid crystal (LC)-filled waveguide, the differential phase can be tuned continuously. This is achieved by means of an analog signal applied to the electrodes, surrounding the LC. The design allows for precise tuning of the differential phase, which is proven with a Monte Carlo measurement resulting in phase errors of less than 3° at 28 GHz. Besides that, the ambient temperature dependency of the module is shown. The phase shifter has a high integration level and can be included into a complete and lightweight single-phased array antenna module. The phase shifter is realized with a high level of integration which is available through the multilayer process of the LTCC. It has a length of 50 and provides a differential phase shift of more than 360° at 28 GHz. The figure of merit for tunable phase shifters is >40°/dB. KW - Passive components and circuits KW - New and emerging technologies and materials PY - 2014 DO - https://doi.org/10.1017/S175907871400083X SN - 1759-0787 SN - 1759-0795 SP - 1 EP - 7 PB - Cambridge Univ. Press CY - Cambridge AN - OPUS4-31198 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gaebler, A. A1 - Moessinger, A. A1 - Goelden, F. A1 - Manabe, A. A1 - Goebel, M. A1 - Follmann, R. A1 - Koether, D. A1 - Modes, C. A1 - Kipka, A. A1 - Deckelmann, M. A1 - Rabe, Torsten A1 - Schulz, Bärbel A1 - Kuchenbecker, Petra A1 - Lapanik, A. A1 - Mueller, S. A1 - Haase, W. A1 - Jakoby, R. T1 - Liquid crystal-reconfigurable antenna concepts for space applications at microwave and millimeter waves N2 - Novel approaches of tunable devices for millimeter wave applications based on liquid crystal (LC) are presented. In the first part of the paper, a novel concept of a tunable LC phase shifter realized in Low Temperature Cofired Ceramics technology is shown while the second part of the paper deals with a tunable high-gain antenna based on an LC tunable reflectarray. The reflectarray features continuously beam scanning in between ±25°. Also first investigations on radiation hardness of LCs are carried out, indicating that LCs might be suitable for space applications. KW - Tunable antenna KW - Phase shifter KW - Liquid crystal KW - LTCC PY - 2009 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-194273 DO - https://doi.org/10.1155/2009/876989 SN - 1687-5877 VL - 2009 IS - Article ID 876989 SP - 1 EP - 7 PB - Hindawi Publishing Corporation CY - New York, NY, USA AN - OPUS4-19427 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -