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81.
Leonie Reinders Stephanie Pfeifer Sarah Kröner Heiko Stolpmann Achim Renfftlen L. Charlyn Greiler Bernd Clauß Michael R. Buchmeiser 《Journal of the European Ceramic Society》2021,41(6):3570-3580
Polycrystalline mullite fibers and novel zirconia-toughened mullite (ZTM) fibers with average diameters between 9.7 and 10.3 μm containing 3, 7 and 15 wt.-% tetragonal ZrO2 (ZTM3, ZTM7, ZTM15) in the final ceramic were prepared via dry spinning followed by continuous calcination and sintering in air. A shift in the formation of transient alumina phases and tetragonal ZrO2 to higher temperatures with increasing amounts of ZrO2 was observed. Concomitantly, the mullite formation temperature was lowered to 1229 °C for ZTM15 fibers. X-ray diffraction revealed formation of the desired tetragonal crystal structure of ZrO2 directly from the amorphous precursor. Room temperature Weibull strengths of 1320, 1390 and 1740 MPa and Weibull moduli of 9.5, 7.1 and 9.0 were determined for mullite, ZTM3 and ZTM15 fibers, respectively. Average Young’s moduli ranged from 190 to 220 GPa. SEM images revealed crack-free fiber surfaces and compact microstructures independent of the amount of ZrO2. 相似文献
82.
Becker S Xu T Ilchmann F Eisler J Wolf B 《Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine》2011,225(12):1196-1201
This paper presents a concept for an implantable micro-pump based on hydrogen-generating gas cells. The gas-generating cell is separated from the drug reservoir by an expandable latex membrane. The system offers linear drug delivery with flowrates ranging from 8 nl/s to 2 microl/s and a total delivery volume of up to 160 ml. Drugs can be dispensed over a wide backpressure range. The device is scalable based on the size of the gas-producing cell and requires no external energy source. Possible fields of application include in vivo local drug delivery for chemotherapy, diabetes, and pain management. 相似文献
83.
84.
Julia Orlik Kathrin Pietsch Achim Fassbender Olena Sivak Konrad Steiner 《Applied Composite Materials》2018,25(4):709-724
Warp-knitted spacer fabrics are considered, which are plates or shells composed of two knitted plane layers connected by vertical beams. Our aim is to compute the effective stiffness and permeability of such spacer fabrics on the basis of their structure and properties of yarns and the monofil. In order to reduce the computational effort and simplify the computational model, homogenization and dimension reduction techniques are applied. They replace the fabric by an equivalent two-dimensional plate or shell with effective elastic properties. To compute the effective permeability, the fluid simulation is done on the fully resolved micro-structure. The paper demonstrates the algorithm on application examples. We compute the elastic properties of a spacer fabric and its effective permeability for different outer-plane compression stages. Numerical examples were performed by applying the multi-scale simulation tools, developed at Fraunhofer ITWM and by comparing with the corresponding experimental results, based on measurements performed at the TU Dresden. The developed algorithms and simulation tools enable a full virtualisation of the material design adapted to exposure scenarios in various technical application cases, i.e. infiltration processes with polymers in the field of fiber reinforced composites, which enables new discoveries for the designing and manufacturing process of 3D warp-knitted spacer fabrics. 相似文献
85.
Sascha Kulas Christian Vogt Andreas Resch Jonas Hartwig Sven Ganske Jonas Matthias Dennis Schlippert Thijs Wendrich Wolfgang Ertmer Ernst Maria Rasel Marcin Damjanic Peter Weßels Anja Kohfeldt Erdenetsetseg Luvsandamdin Max Schiemangk Christoph Grzeschik Markus Krutzik Andreas Wicht Achim Peters Sven Herrmann Claus Lämmerzahl 《Microgravity science and technology》2017,29(1-2):37-48
86.
Hua Lv Alessandra da Silva Adriana I. Figueroa Charles Guillemard Iván Fernández Aguirre Lorenzo Camosi Lucia Aballe Manuel Valvidares Sergio O. Valenzuela Jürgen Schubert Martin Schmidbauer Jens Herfort Michael Hanke Achim Trampert Roman Engel-Herbert Manfred Ramsteiner Joao Marcelo J. Lopes 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(39):2302387
Van der Waals (vdW) heterostructures combining layered ferromagnets and other 2D crystals are promising building blocks for the realization of ultracompact devices with integrated magnetic, electronic, and optical functionalities. Their implementation in various technologies depends strongly on the development of a bottom-up scalable synthesis approach allowing for realizing highly uniform heterostructures with well-defined interfaces between different 2D-layered materials. It is also required that each material component of the heterostructure remains functional, which ideally includes ferromagnetic order above room temperature for 2D ferromagnets. Here, it is demonstrated that the large-area growth of Fe5−xGeTe2/graphene heterostructures is achieved by vdW epitaxy of Fe5−xGeTe2 on epitaxial graphene. Structural characterization confirms the realization of a continuous vdW heterostructure film with a sharp interface between Fe5−xGeTe2 and graphene. Magnetic and transport studies reveal that the ferromagnetic order persists well above 300 K with a perpendicular magnetic anisotropy. In addition, epitaxial graphene on SiC(0001) continues to exhibit a high electronic quality. These results represent an important advance beyond nonscalable flake exfoliation and stacking methods, thus marking a crucial step toward the implementation of ferromagnetic 2D materials in practical applications. 相似文献
87.
In the world of large‐scale applications, software as a service (SaaS) in general and use of microservices, in particular, is bringing service‐oriented architectures to a new level: Systems in general and systems that interact with human users (eg, sociotechnical systems) in particular are built by composing microservices that are developed independently and operated by different parties. At the same time, SaaS applications are used more and more widely by enterprises as well as public services for providing critical services, including those processing security or privacy of relevant data. Therefore, providing secure and reliable service compositions is increasingly needed to ensure the success of SaaS solutions. Building such service compositions securely is still an unsolved problem. In this paper, we present a framework for modelling, validating, and ranking secure service compositions that integrate both automated services as well as services that interact with humans. As a unique feature, our approach for ranking services integrates validated properties (eg, based on the result of formally analysing the source code of a service implementation) as well as contractual properties that are part of the service level agreement and, thus, not necessarily ensured on a technical level. 相似文献
88.
DNA Primer Extension with Cyclopropenylated 7‐Deaza‐2′‐deoxyadenosine and Efficient Bioorthogonal Labeling in Vitro and in Living Cells
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Dr. Damian Ploschik Dr. Franziska Rönicke Hanna Beike Dr. Ralf Strasser Prof. Dr. Hans‐Achim Wagenknecht 《Chembiochem : a European journal of chemical biology》2018,19(18):1949-1953
A deoxyadenosine triphosphate (dATP) analogue for DNA labeling was synthesized with the 1‐methylcyclopropene (1MCP) group at the 7‐position of 7‐deaza‐2′‐deoxyadenosine and applied for primer extension experiments. The real‐time kinetic data reveals that this 1MCP‐modified dATP analogue is incorporated into DNA much faster than that of the similarly 1MCP‐modified deoxyuridine triphosphate (dUTP) analogue. The postsynthetic fluorescent labeling of these oligonucleotides works efficiently according to PAGE analysis, and can be applied for immobilization of a functional antibody on a surface. Site‐specific labeling at two different positions in DNA was achieved and the bioorthogonality of the postsynthetic fluorescent labeling was demonstrated in living HeLa cells. 相似文献
89.
90.
We studied spatially isolated single-walled carbon nanotubes (SWNTs) immobilized in a quasi-planar optical lambda/2-microresonator using confocal microscopy and spectroscopy. The modified photonic mode density within the resonator is used to selectively enhance or inhibit different Raman transitions of SWNTs. Experimental spectra are presented that exhibit single Raman bands only. Calculations of the relative change in the Raman scattering cross sections underline the potential of our microresonator for the optical control of nonequilibrium phonon populations in SWNT. 相似文献