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Publication0.15 mu-m passivated InP-based HEMT MMIC technology with high thermal-stability in hydrogen ambient( 2000)
;Chertouk, M.Weimann, G. -
Publication0.15 mym T-gate e-beam lithography using crosslinked P/MMA/MAA developed in ortho-xylene resulting in high contrast and high plasma stability for dry etched recess gate pseudomorphic MODFETs for MMIC production( 1994)
;Hülsmann, A. ;Mühlfriedel, E. ;Raynor, B. ;Glorer, K. ;Schneider, J. ;Braunstein, J. ;Schlechtweg, M. ;Tasker, P.J. ;Thiede, A.Jakobus, T.Pseudomorphic AlGaAs/InGaAs/GaAs modulation doped FETs (Psi-MODFETs) with sub quarter micron gate length are used in millimeter-wave amplifiers. To reduce the noise figure and enhance the cut-off frequency T-gate technology is required. To enhance device reliability and yield, the gate recess depth and width must be precisely controlled. Selective reactive ion etching (RIE) of GaAs on thin AlGaAs etch stop layers using Freon-12 as an etch gas satisfies these conditions. The e-beam patterned T-gate resist profile has to withstand this dry-etched gate recess process. Using a novel three layer resist system with crosslinked P(MMA/MAA) we were able to produce 76 GHz amplifiers with a gain of 21 dB, broadband amplifiers 5-80 GHz with 9 dB gain and dynamic frequency dividers operating in a range of 26-51 GHz based on 0.15 mym T-gate pseudomorphic MODFETs. -
Publication0.48Tb/s (12x40Gb/s) WDM transmission and high-quality thermo-optic switching in dielectricloaded plasmonics( 2012)
;Kalavrouziotis, D. ;Papaioannou, S. ;Giannoulis, G. ;Apostolopoulos, D. ;Hassan, K. ;Markey, L. ;Weeber, J.-C. ;Dereux, A. ;Kumar, A. ;Bozhevolnyi, S.I. ;Baus, M. ;Karl, M. ;Tekin, T. ;Tsilipakos, O. ;Pitilakis, A. ;Kriezis, E.E. ;Avramopoulos, H. ;Vyrsokinos, K.Pleros, N.We demonstrate Wavelength Division Multiplexed (WDM)- nabled transmission of 480Gb/s aggregate data traffic (12x40Gb/s) as well s high-quality 1x2 thermo-optic tuning in Dielectric-Loaded Surface lasmon Polariton Waveguides (DLSPPWs). The WDM transmission haracteristics have been verified through BER measurements by exploiting he heterointegration of a 60m-long straight DLSPPW on a Silicon-on-Insulator waveguide platform, showing error-free erformance for six out of he twelve channels. High-quality thermo-optic tuning has been achieved by tilizing Cycloaliphatic-Acrylate-Polymer as an efficient thermo-optic olymer loading employed in a dual-resonator DLSPPW switching tructure, yielding a 9nm wavelength shift and extinction ratio values higher han 10dB at both output ports when heated to 90°C. -
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Publication0.5-Gb/s OFDM-Based Laser Data and Power Transfer Using a GaAs Photovoltaic Cell( 2018)
;Fakidis, J. ;Videv, S.Haas, H.In this letter, we demonstrate for the first time the additional capability of high-speed data communication for single-junction photovoltaic (PV) cells. A record 3-dB bandwidth of 24.5 MHz is reported for a gallium arsenide (GaAs) PV cell. The PV cell is shown to achieve a power efficiency of at least 42% when irradiance of 0.46 W/cm2 is received from 847-nm vertical-cavity surface-emitted laser. Optimized bit-and-power-loaded optical orthogonal frequency-division multiplexing (OFDM) is applied to use the communication bandwidth most efficiently. With this, a data rate of 0.5 Gb/s is achieved for a 2-m OFDM-based laser link. To the best of our knowledge, the reported data rates achieved with a GaAs PV cell as the detector are the highest for simultaneous optical wireless information and power transfer. -
Publication(001)-Textured Growth of Diamond Films on Polycrystalline Diamond Substrates by Bias-assisted Chemical Vapor Deposition( 1997)
;Jiang, X. ;Klages, C.-P.Zhang, W.J. -
Publication1 + 1 > 2 Benchmarking und Lean-Index zur Steigerung der Lagerleistung( 2015)
;Jehle, FranziskaSeidler, TobiasDie Philosophie einer schlanken Unternehmensführung, auch bekannt als "Lean Management", hat sich inzwischen weltweit in nahezu allen Branchen, insbesondere in Produktionsbetrieben, erfolgreich etabliert. Aber auch in der Logistik bietet sich das Prinzip an. Das Fraunhofer SCS befasst sich seit langem mit der Effizienzsteigerung von Lagern. Für eine fundierte Leistungsbewertung empfehlen die Forscher eine Kombination von Lager-Benchmarking und der Ermittlung eines Lager-Lean-Index, woraus sich ein Maßnahmenplan zur Leistungsverbesserung ableiten lässt. -
Publication1 GBit/s-Datentransfer für eine bildgebende Matrix( 1996)
;Bürger, B. ;Kluge, W.Winkler, J. -
Publication1 H-NMR relaxation studies of cured natural rubbers with different carbon black fillers( 1999)
;Leisen, J. ;Breidt, J.Kelm, J. -
Publication1 kW 1 mJ eight-channel ultrafast fiber laser( 2016)
;Müller, M. ;Kienel, M. ;Klenke, A. ;Gottschall, T. ;Shestaev, E. ;Plötner, M. ;Limpert, J.Tünnermann, A.An ultrafast fiber chirped-pulse amplifier comprising eight coherently combined amplifier channels is presented. The laser delivers 1 kW average power at 1 mJ pulse energy and 260 fs pulse duration. Excellent beam quality and low-noise performance are confirmed. The laser has proven suitable for demanding scientific applications. Further power scaling is possible right away using even more amplifier channels. -
Publication1 kW, 10 mJ, 120 fs coherently combined fiber CPA laser system( 2021)
;Stark, H. ;Buldt, J. ;Müller, M. ;Klenke, A.Limpert, J.An ultrafast fiber chirped-pulse amplification laser system based on a coherent combination of 16 ytterbium-doped rod-type amplifiers is presented. It generates 10 mJ pulse energy at 1 kW average power and 120 fs pulse duration. A partially helium-protected, two-staged chirped-pulse amplification grating compressor is implemented to maintain the close to diffraction-limited beam quality by avoiding nonlinear absorption in air. -
Publication1 MHz repetition rate hollow fiber pulse compression to sub-100-fs duration at 100 W average power( 2011)
;Rothhardt, J. ;Hädrich, S. ;Carstens, H. ;Herrick, N. ;Demmler, S. ;Limpert, J.Tünnermann, A.We report on nonlinear pulse compression at very high average power. A high-power fiber chirped pulse amplification system based on a novel large pitch photonic crystal fiber delivers 700 fs pulses with 200 mu J pulse energy at a 1 MHz repetition rate, resulting in 200 W of average power. Subsequent spectral broadening in a xenon-filled hollow-core fiber and pulse compression with chirped mirrors is employed for pulse shortening and peak power enhancement. For the first time, to our knowledge, more than 100 W of average power are transmitted through a noble-gas-filled hollow fiber. After pulse compression of 81 fs, 93 mu J pulses are obtained at a 1 MHz repetition rate. -
Publication1 Prozent für die Logistikforschung: Interview( 2011)
;Klinker, R.Würmser, A.Der eine ist Wissenschaftler und Forscher aus Leidenschaft, der andere engagiert sich als Manager für den Wirtschaftsbereich Logistik. Begeistert diskutieren der Fraunhofer-IML-Chef Professor Michael ten Hompel und der Vorstandvorsitzende der Bundesvereinigung Logistik, Prof. Raimund Klinker, über Image, Investitionen und Inhalte der Logistikforschung. -
Publication[1,2,4] Triazolo[1,5-c]quinazolin-2-amines-potent-adenosine A(1) and A(2A) receptor antagonists( 2012)
;Ghattas, Wadih ;Burbiel, Joachim C. ;Hockemeyer, JörgMüller, Christa E. -
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Publication1,3-diketone fluids and their complexes with iron( 2013)
;Walter, M. ;Amann, T. ;Li, K. ;Kailer, A. ;Rühe, J.Moseler, M.Tribological experiments with 1,3-diketone fluids in contact with iron surfaces show ultralow friction, which was suggested to be connected to the formation of iron complexes. In order to support this assumption, we calculate infrared and optical spectra of various substituted 1,3-diketones and their iron complexes using gradient-corrected density functional theory (DFT). The description of the complexes requires the application of the DFT+U scheme for a correct prediction of the high spin state on the central iron atom. With this approach, we obtain excellent agreement between experiment and simulation in infrared and optical spectra, allowing for the determination of 1,3-diketone tautomeric forms. The match in the spectra of the complex strongly supports the assumption of iron complex formation by these lubricants. -
Publication1,3-Dioxolane, tetrahydrofuran, acetylacetone and dimethyl sulfoxide as solvents for non-aqueous vanadium acetylacetonate redox-flow-batteries( 2013)
;Herr, T.A non-aqueous vanadium acetylacetonate redox flow battery with different organic solvents and tetrabutylammonium hexafluorophosphate has been investigated. Cyclic voltammograms show three redox couples in 1,3-dioxolane, tetrahydrofuran, acetylacetone and two redox couples in dimethyl sulfoxide. Cell potentials between 2.21 and 2.61V are measured, depending on the solvent used. Impedance Spectroscopy has been used to determine rate limiting step in the non-aqueous redox flow battery. Experiments in a charge-discharge test cell yielded coulombic and energy efficiencies of 85.9-98.5% and 26.6-43.6%, respectively. -
Publication1,3-dipolar cycloadditions of azides and alkynes: A universal ligation tool in polymer and materials science( 2007)Lutz, J.-F.In 2001, Sharpless and co-workers introduced "click" chemistry, a new approach in organic synthesis that involves a handful of almost perfect chemical reactions. Among these carefully selected reactions, Huisgen 1,3-dipolar cycloadditions were shown to be the most effective and versatile and thus became the prime example of click chemistry. Hence, these long-neglected reactions were suddenly re-established in organic synthesis and, in particular, have gained popularity in materials science. The number of publications dealing with click chemistry has grown exponentially over the last two years. The Minireview discusses whether click chemistry is a miracle tool or an ephemeral trend.
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Publication1,3-Propanediol and its application in bio-based polyesters for resin applications( 2019)
;Kluge, Marcel ;Pérocheau Arnaud, SachaPolyester resins are important raw materials for a myriad of applications especially in the field of coatings and radical curing polymers, such as wood and powder coatings, molding compounds, and UV-curing applications. In addition, polyols derived from polyester resins are precursors for the synthesis of polyurethanes and polycarbonates. Besides dicarboxylic acid, diols are used as monomers in these polyesters. To date most of the diols utilized are derived from petrochemical feedstock. To increase the bio-based content of polyester resins, novel diols derived from renewable resources are of special interest. In this respect, 1,3-propanediol has drawn considerable attention over the last years. It is accessible via microbial fermentation of glucose from starch at a competitive price in sufficient amounts. Therefore, 1,3-propanediol could be a valuable alternative to petrochemical diols, such as 1,6-hexanediol and neopentylglycol, which are currently used as diols in most resin applications. This article gives a brief overview over the utilization of 1,3-propanediol in high molecular weight polyesters for plastic application followed by a more detailed discussion of the most relevant work in the field of polyester resins derived from 1,3-propanediol. -
Publication1-Ethynyl ethers as efficient thermal crosslinking system for hole transport materials in OLEDs( 2016)
;Limberg, F.R.P. ;Schneider, T. ;Höfle, S. ;Reisbeck, F. ;Janietz, S. ;Colsmann, A.Krüger, H.A new crosslinking concept based on a thermally activated one-component building block with thermally initiated crosslinkable ynol ether is introduced. For polystyrene matrices with glass transition temperatures below the reaction temperature, full conversion is reached within 30 min at 160 °C without employing any catalysts or co-reactants. The ynol ethers are chemically inert toward a variety of reaction conditions (e.g., radicals and strong bases) and consequently applicable to a wide range of materials for organic electronics. The crosslinkable solid compounds are bench-stable over more than a year. The broad applicability is demonstrated with a liquid model compound and a specifically designed crosslinking monomer introduced successfully as building block into polystyrenes with pending hole transporting groups. A detailed study of crosslinking kinetics by infrared measurements as well as an alternative method of crosslinker content determination utilizing differential scanning calorimetry is presented. The crosslinkable polymer and the corresponding noncrosslinkable molecule tris(4-(3,6-dibutoxy-9H-carbazol-9-yl)phenyl)amine (BuO6TCTA) are synthesized and investigated as hole transport layers (HTLs) in phosphorescent organic light emitting diodes (OLEDs). OLEDs with crosslinked and noncrosslinked HTLs show efficiencies around 80 cd A−1, indicating negligible influence of the crosslinking process on the device performance while yielding better HTL durability against solvent rinsing.