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| 2. |
- Montelius, L., et al.
(författare)
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Pattern recognition of nerve signals using an artificial neural network
- 1996
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Ingår i: ; , s. 1502-1503
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Konferensbidrag (refereegranskat)abstract
- By using a microfabricated nerve chip with integrated electrodes through which peripheral nerves can generate and make electrical connects, it should be possible to control a remote prosthesis by processing the detected nerve signals. In this study different artificial neural networks have been employed for classification of such complex patterns of signals. The signals were obtained from four electrodes detecting muscle activity in a rat hindlimb as a consequence of applied stimulus to the rat right hindpaw. These signals recorded at four different sites resembles a situation of a nerve chip with four electrodes, which implies that we might be able to use the same strategy when analyzing data from a four-electrode chip to obtain information from the nervous system. In this paper we will address the usefulness of different network topologies for analyzing measured in-vivo data from an implanted perforated nerve chip.
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| 3. |
- Carlsson, N, et al.
(författare)
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IMPROVED SIZE HOMOGENEITY OF INP-ON-GAINP STRANSKI-KRASTANOW ISLANDS BY GROWTH ON A THIN GAP INTERFACE LAYER
- 1995
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Ingår i: Journal of Crystal Growth. - : Elsevier BV. - 0022-0248. ; 156:1-2, s. 23-29
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Tidskriftsartikel (refereegranskat)abstract
- Coherent InP nano-sized islands, embedded into GaInP, have been grown by metal-organic vapour phase epitaxy using the Stranski-Krastanow growth mode. Photoluminescence, atomic force microscopy and transmission electron microscopy studies show that the insertion of a thin ∼ 4 monolayer thick GaP layer affects the critical thickness of the subsequently deposited two-dimensional InP wetting layer, increasing it from ∼ 1.5 monolayers (without an inserted GaP layer) to ∼ 2.5 monolayers (with an inserted GaP layer). We demonstrate that the inserted GaP layer affects also the island formation. The bimodal size distribution of Stranski-Krastanow islands, typical for low InP coverages, can be overcome without island coalescence by deposition on top of the thin GaP layer, where a coverage of InP of about 3.5–4.5 monolayers results in the formation of almost only the larger, fully developed, pyramidal islands. Annealing experiments at growth temperature of 580°C show that these islands (base area ≈ 40 × 50 nm2, height ≈ 10–15 nm, surface density ≈ (1−2) × 109 cm−2) are rather stable in a time-scale over several minutes before they slowly undergo an Ostwald ripening process.
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| 4. |
- Malmqvist, L, et al.
(författare)
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Liquid-target laser-plasma source for X-ray lithography
- 1997
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Ingår i: Microelectronic Engineering. - 1873-5568. ; 35:1-4, s. 535-536
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Tidskriftsartikel (refereegranskat)abstract
- We describe a compact and practically debris-free laser-plasma x-ray source suitable for proximity lithography. The source is based on a microscopic fluorocarbon continuous liquid jet droplet target, generating high-brightness lambda=1.2-1.7 nm x-ray emission with similar to 5% conversion efficiency. This target type has the advantages of producing only negligible amounts of debris, and being regenerative, thereby allowing high-repetition-rate uninterrupted operation. The source is combined with an Au/SiNx x-ray mask to demonstrate lithography of sub-100 nm structures in SAL-601 chemically enhanced resist.
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| 5. |
- Malmqvist, L, et al.
(författare)
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Nanometer table-top proximity x-ray lithography with liquid-target laser-plasma source
- 1997
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Ingår i: Journal of Vacuum Science and Technology B. - : American Vacuum Society. - 1520-8567. ; 15:4, s. 814-817
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Tidskriftsartikel (refereegranskat)abstract
- A compact laser-plasma proximity x-ray lithography system suitable for laboratory-scale low-volume nanometer patterning is presented. The laser-plasma source, which is based on a fluorocarbon liquid-jet target, generates high-brightness lambda = 1.2-1.7 nm x-ray emission with only negligible debris production. The Au/SiNx x-ray mask is fabricated by employing ion milling and a high-contrast e-beam resist. With SAL-601 chemically enhanced resist we demonstrate fabrication of high-aspect-ratio, sub-100 nm structures. The exposure time is currently 20 min using a compact 10 Hz, lambda = 532 nm, 70 mJ/pulse mode-locked Nd:YAG laser. However, the regenerative liquid-jet target is designed for operation with future, e.g., 1000 Hz, lasers resulting in projected exposure times of similar to 10 s. (C) 1997 American Vacuum Society.
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| 6. |
- MONTELIUS, L, et al.
(författare)
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CHARACTERIZATION OF THE MN ACCEPTOR LEVEL IN GAAS
- 1988
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Ingår i: Journal of Applied Physics. - CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 : AIP Publishing. - 0021-8979 .- 1089-7550. ; 64, s. 1564-1567
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Tidskriftsartikel (refereegranskat)
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| 7. |
- Wallman, L, et al.
(författare)
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Perforated silicon nerve chips with doped registration electrodes : in vitro performance and in vivo operation
- 1999
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Ingår i: IEEE Transactions on Biomedical Engineering. - 1558-2531. ; 46:9, s. 73-1065
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Tidskriftsartikel (refereegranskat)abstract
- An in vitro model was developed for the study of signal transduction between a Cu-wire, miming a neural signal source, and recording electrodes on perforated silicon chips. Phosphorous doped electrodes were used to achieve an all silicon device. The model was used to study signal amplitude as a function of the spatial position, and distance to the signal source. Recordings of the signal crosstalk to neighboring electrodes on the chips were made. It was found that the amplitude decreased by a factor of two at a distance of 50 microns between the electrode surface and the signal source. The chip electrode signal crosstalk was found to be 6 dB using an external reference electrode. Improvements were accomplished with an on chip reference electrode giving a crosstalk suppression of 20 dB. Impedance analysis showed that doped silicon electrodes displayed similar characteristics as Cu-electrodes at frequencies above 3 kHz. Sieve electrodes were implanted in the rat sciatic nerve and following a 10-week nerve regeneration period the dorsal and ventral (L5) roots in the spinal cord were stimulated. Compound action potentials were recorded via the chip. Stimulating the regenerated sciatic nerve via the sieve electrode also induced lower leg muscle contraction activity.
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| 8. |
- Wallman, L., et al.
(författare)
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Silicon sieve electrodes for neural implants - in vitro characterization & in vivo recordings
- 1998
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Ingår i: Procceedings of the 20th Annual International Conference of the IEEE Engineering in Medicine and Biology Society : Biomedical Engineering Towards the Year 2000 and Beyond - Biomedical Engineering Towards the Year 2000 and Beyond. - 0780351649 ; 20, s. 2225-2228, s. 2225-2228
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Konferensbidrag (refereegranskat)abstract
- An in vitro model was developed to characterize the electrical properties of silicon microfabricated recording electrodes, using a Cu-wire mimicing a neural signal source. Phosphorous doped electrodes were used to achieve an all silicon device. The model was used to study signal amplitude as a function of distance between the electrode surface and the signal source. Signal crosstalk to neighbouring electrodes on the chips were recorded. The crosstalk was found to be 6 dB using an external reference electrode. Improvements were accomplished with an on chip reference electrode giving an amplitude crosstalk suppression of 20 dB. It was found that the amplitude decreased by a factor of 2 at a distance of 50 μm between the electrode surface and the signal source. Sieve electrodes were also implanted in the rat sciatic nerve and following a 10 week nerve regeneration period the dorsal and ventral (L5) roots in the spinal cord were stimulated. Compound action potentials were recorded via the chip. Lower leg muscle contraction activity was also induced by stimulating the regenerated sciatic nerve via the sieve electrode.
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