Refine
Year of publication
Document Type
- Article (reviewed) (557) (remove)
Language
- English (557) (remove)
Keywords
- Dünnschichtchromatographie (17)
- Adsorption (10)
- Metallorganisches Netzwerk (9)
- Lithiumbatterie (8)
- Plastizität (8)
- 3D printing (7)
- Energieversorgung (6)
- Ermüdung (6)
- Finite-Elemente-Methode (6)
- Intelligentes Stromnetz (6)
Institute
- Fakultät Maschinenbau und Verfahrenstechnik (M+V) (256)
- Fakultät Elektrotechnik und Informationstechnik (E+I) (bis 03/2019) (112)
- Fakultät Elektrotechnik, Medizintechnik und Informatik (EMI) (ab 04/2019) (99)
- INES - Institut für nachhaltige Energiesysteme (97)
- Fakultät Wirtschaft (W) (60)
- ivESK - Institut für verlässliche Embedded Systems und Kommunikationselektronik (25)
- IfTI - Institute for Trade and Innovation (13)
- POIM - Peter Osypka Institute of Medical Engineering (13)
- Fakultät Medien und Informationswesen (M+I) (bis 21.04.2021) (12)
- Fakultät Medien (M) (ab 22.04.2021) (11)
Open Access
- Open Access (249)
- Closed Access (182)
- Gold (65)
- Closed (43)
- Hybrid (20)
- Diamond (15)
- Bronze (3)
- Grün (1)
The embedding of microwave devices is treated by applying the finite-difference method to three-dimensional shielded structures. A program package was developed to evaluate electromagnetic fields inside arbitrary transmission-line connecting structures and to compute the scattering matrix. The air bridge, the transition through a wall, and the bond wire are examined as interconnecting structures. Detailed results are given and discussed regarding the fundamental behavior of embedding.
It is demonstrated that microwave structures incorporating dielectric resonators (DR) are accurately characterised by means of a 3-dimensional finite-difference CAD package. All major assumptions made so far have been dropped, offering the possibility of a rigorous analysis of the embedding of dielectric resonators into microwave structures. In particular, a finite thickness for the microstrip conductor has been taken into account. The coupling of the DR to a microstrip placed in a metallic housing has been theoretically and experimentally investigated. Theoretical and experimental results are in good agreement and give new insight into DR coupling to microstrip circuits.
The advantages of the coupled-mode (COM) formalism and the transmission-matrix approach are combined in order to create exact and computationally efficient analysis and synthesis tools for the design of coupled surface acoustic wave resonator filters. The models for the filter components, in particular gratings, interdigital transducers (IDTs) and multistrip couplers (MSCs), are based on the COM approach that delivers closed-form expressions. To determine the pertinent COM parameters, the COM differential equations are solved and the solution is compared with analytically derived expressions from the transmission-matrix approach and the Green's function method. The most important second-order effects, such as energy storage, propagation loss, and mechanical and electrical loading, are fully taken into account. As an example, a two-pole, acoustically coupled resonator filter at 914.5 MHz on AT quartz is investigated. Excellent agreement between theory and measurement is found.
This paper treats the interaction between acoustic modes and light (Brillouin scattering) in a single mode optical fibre. Different observed spectra of the Brillouin backscattering in several fibres have been already reported. In order to have a clear idea of the process, we made a simulation to be able to `draw' the theoretical Brillouin spectrum of an optical fibre and to identify the origin of the observed backscattered lines.
First, the model and the computation method used in our simulation are described. Second, the experimentally observed spectra of two real fibres are compared with their computed spectra. Real spectra and simulated spectra are in good agreement.
Our work provides an interesting tool to investigate the changes in the Brillouin spectrum when the input parameters (characteristics of an optical fibre) vary. This should give useful indications to people working on systems which use Brillouin backscattering.
Formal verification (FV) is considered by many to be complicated and to require considerable mathematical knowledge for successful application. We have developed a methodology in which we have added formal verification to the verification process without requiring any knowledge of formal verification languages. We use only finite-state machine notation, which is familiar and intuitive to designers. Another problem associated with formal verification is state-space explosion. If that occurs, no result is returned; our method switches to random simulation after one hour without results, and no effort is lost. We have compared FV against random simulation with respect to development time, and our results indicate that FV is at least as fast as random simulation. FV is superior in terms of verification quality, however, because it is exhaustive.
The flow field-flow fractionation (FIFFF) technique is a promising method for separating and analysing particles and large size macromolecules from a few nanometers to approximately 50 μm. A new fractionation channel is described featuring well defined flow conditions even for low channel heights with convenient assembling and operations features. The application of the new flow field-flow fractionation channel is proved by the analysis of pigments and other small particles of technical interest in the submicrometer range. The experimental results including multimodal size distributions are presented and discussed.
An algorithm is presented that has successfully been utilized in practice for several years. It improves data analysis in chromatography. The program runs in an extremely reliable way and evaluates chromatographic raw data with an acceptable error. The algorithm requires a minimum of preliminaries and integrates even unsmoothed noisy data correctly.
We generalize the fluid flow problem of an oscillating flat plate (II. Stokes problem) in two directions. We discuss first the oscillating porous flat plate with superimposed blowing or suction. The second generalization is concerned with an increasing or decreasing velocity amplitude of the oscillating flat plate. Finally we show that a combination of both effects is possible as well.