| 1. |
- Hallberg, Håkan, et al.
(författare)
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Modeling of Continuous Dynamic Recrystallization in Aluminum
- 2009
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Ingår i: DCE Technical Memorandum No. 11. - 1901-7278. ; 11, s. 59-62
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Konferensbidrag (refereegranskat)abstract
- A constitutive model is presented, considering grain size refinement through continuous dynamic recrystallization together with an evolving dislocation density. The grain refinement is allowed to influence both the evolution of the dislocation density and the rate dependence of the material. The model is calibrated against experimental data on aluminum and numerical simulations of equal channel angular pressing (ECAP) material processing illustrates the capabilities of the model.
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| 2. |
- Kristensen, Fredrik, et al.
(författare)
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A Flexible FFT Processor
- 2002
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Konferensbidrag (refereegranskat)abstract
- In this paper a flexible FFT processor for OFDM systems is presented. In future wireless systems using OFDM each terminal should be able to handle a wide range of different applications, from pure voice communication to high-speed data transfers, with as little overhead in power consumption and protocol procedure as possible. As the terminals will be battery powered and should be cheap to manufacture an ASIC solution is required. To be able to adapt to different communication schemes and various communication channels the FFT processor must be configurable. To minimize power consumption no more precision than necessary should be used. A pipelined radix22 FFT processor, with the possibility of run time switching between 32-1024 points, have been designed in a standard CMOS 0.35 µm technology. Clock gating and low power memories have been used to reduce power consumption.
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| 3. |
- Kristensen, Fredrik, et al.
(författare)
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A Generic Transmitter for Wireless OFDM Systems
- 2003
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Ingår i: 14th IEEE Proceedings on Personal, Indoor and Mobile Radio Communications, 2003. PIMRC 2003.. - 0780378229 ; 3, s. 2234-2238
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Konferensbidrag (refereegranskat)
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| 4. |
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| 5. |
- Kristensen, Fredrik, et al.
(författare)
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Flexible baseband transmitter for OFDM
- 2003
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Ingår i: Proceedings of the IASTED International Conference on Circuits, Signals, and Systems. - 0889863512 ; , s. 356-361
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Konferensbidrag (refereegranskat)abstract
- To fully utilize the available spectrum for a wireless communication system it is feasible to adapt to different situations on the channel. In this paper a flexible OFDM transmitter is presented together with basic theory behind OFDM transmission. It is shown that high flexibility can be obtained with a reasonable amount of additional hardware. Part of the design, the FFT-processor, has already been fabricated and measurement results are presented.
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| 6. |
- Kristensen, Fredrik, et al.
(författare)
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Reduced transceiver-delay for OFDM systems
- 2004
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Ingår i: 2004 IEEE 59th Vehicular Technology Conference. VTC 2004-Spring. - 0780382552 ; , s. 1242-1245
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Konferensbidrag (refereegranskat)abstract
- In this paper, it is shown that more than half of the data flow buffer, due to a bit reversed FFT output and cyclic prefix in an OFDM transceiver, can be removed. To achieve this, a new pipelined FFT processor is proposed and a cyclic suffix is used instead of the more commonly used cyclic prefix. The FFT processor is used either with a forward or backward data flow, i.e. performing either a decimation in time or a decimation in frequency FFT. However, this approach precludes wordlength optimization in the processor and therefore a semi floating-point arithmetic is used to achieve high signal-to-noise ratio. Total delay through the transceiver is reduced by 25% and for larger transceivers silicon area is reduced by as much as 25%. In addition, the proposed scheme reduces the required amount of memory accesses to insert a cyclic extension, and has the basic properties of a simple interleaver
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| 7. |
- McGinn, Steven, et al.
(författare)
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New Technologies for DNA analysis-A review of the READNA Project.
- 2016
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Ingår i: New Biotechnology. - : Elsevier BV. - 1876-4347 .- 1871-6784.
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Forskningsöversikt (refereegranskat)abstract
- The REvolutionary Approaches and Devices for Nucleic Acid analysis (READNA) project received funding from the European Commission for 4 1/2 years. The objectives of the project revolved around technological developments in nucleic acid analysis. The project partners have discovered, created and developed a huge body of insights into nucleic acid analysis, ranging from improvements and implementation of current technologies to the most promising sequencing technologies that constitute a 3(rd) and 4(th) generation of sequencing methods with nanopores and in situ sequencing, respectively.
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| 8. |
- Mosén, Kristina, et al.
(författare)
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Particle formation and capture during spray drying of inhalable particles
- 2004
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Ingår i: Pharmaceutical Development and Technology. - 1083-7450. ; 9:4, s. 409-417
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Tidskriftsartikel (refereegranskat)abstract
- An investigation of the spray drying process is made in great detail regarding particle formation and capture efficiency with focus on the production of inhalable particles. Mannitol was spray dried as model substance and the spray-dried products were characterized. The resulting products consisted of smooth spheres with a volume median diameter of 2.2-5.5 mum, and narrow size distributions. The investigation was performed in pilot scale of sufficient size to draw general conclusions and make some recommendations. It has been shown that the size of particles is decreased when the feed concentration is decreased, the nozzle gas/feed flow mass ratio increased, and the droplet size decreased. The collection efficiency of the cyclone device used in this study was shown to have a cut-off of 2 mum, i.e., 50% of the particles less than 2 mum are not captured. The data reported indicate that the majority of the single particles formed here, <5 μm, arise from single droplets (of about 10 μm) and are solid, nonporous particles.
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| 9. |
- Mosén, Kristina, et al.
(författare)
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The apparent plasticizing effect of polyethylene glycol (PEG) on the crystallinity of spray dried lactose/PEG composites
- 2006
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Ingår i: European Journal of Pharmaceutics and Biopharmaceutics. - : Elsevier BV. - 0939-6411. ; 64:2, s. 206-211
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Tidskriftsartikel (refereegranskat)abstract
- Aqueous solutions of lactose and polyethylene glycol (PEG) were spray dried in a Buchi Model 191 spray dryer with the aim to investigate the effect of PEG on the crystallinity of the composite. A PEG concentration of 10.7% by weight of solids was studied for PEG 200, 600, 1500, 4000 and 8000. For PEG 200 and 4000 additional concentrations from 1.5-19.3% to 1.5-32.4%, respectively, were investigated. The spray dried composites were analysed with X-ray powder diffraction and modulating differential scanning calorimetry. The crystallinity of lactose in the composites varied from 0% to 60%, dependent on the molecular weight and concentration of PEG. Apparently, lactose crystallinity is promoted by low molecular weight and high concentration of the PEG. PEG did not affect the lactose glass transition temperature. It is suggested that lactose and PEG are solidified separately during spray drying and that partial crystallization of lactose is associated with effects of PEG on the rate of drying.
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| 10. |
- Ahadi, Aylin, et al.
(författare)
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Simulation of Nanoindentation Response of Empty and Filled Viral Capsids
- 2009
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Ingår i: DCE Technical Memorandum. - 1901-7278. ; 11
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Konferensbidrag (refereegranskat)abstract
- The nanoindentation response of empty and filled viral capsids is modelled using three dimensional finite element analysis. Simulation with two different geometries, spherical and icosahedral, are performed using the finite element code Abaqus. The capsids are modeled as non-linear Hookean elastic and both small and large deformation analysis is performed. Force-indentation curves for three different viral capsids are directly compared to experimental data and the Young’s modulus is determined by calibrating the force-indentation curve to data from atomic force microscopy (AFM) experiments. Predictions are made for two additional viral capsids. The results from the simulation showed a good agreement with AFM data, see [1].
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