| 1. |
- Backenius, Erik, 1974-
(författare)
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On Reduction of Substrate Noise in Mixed-Signal Circuits
- 2005
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Microelectronics is heading towards larger and larger systems implemented on a single chip. In wireless communication equipment, e.g., cellular phones, handheld computers etc., both analog and digital circuits are required. If several integrated circuits (ICs) are used in a system, a large amount of the power is consumed by the communication between the ICs. Furthermore, the communication between ICs is slow compared with on-chip communication. Therefore, it is favorable to integrate the whole system on a single chip, which is the objective in the system-on-chip (SoC) approach.In a mixed-signal SoC, analog and digital circuits share the same chip. When digital circuits are switching, they produce noise that is spread through the silicon substrate to other circuits. This noise is known as substrate noise. The performance of sensitive analog circuits is degraded by the substrate noise in terms of, e.g., lower signal-to-noise ratio and lower spurious-free dynamic range. Another problem is the design of the clock distribution net, which is challenging in terms of obtaining low power consumption, sharp clock edges, and low simultaneous switching noise.In this thesis, a noise reduction strategy that focus on reducing the amount of noise produced in digital clock buffers, is presented. The strategy is to use a clock with long rise and fall times. It is also used to relax the constraints on the clock distribution net, which also reduce the design effort. Measurements on a test chip show that the strategy can be implemented in an IC with low cost in terms of speed and power consumption. Comparisons between substrate coupling in silicon-on-insulator (SOI) and conventional bulk technology are made using simple models. The objective here is to get an understanding of how the substrate coupling differs in SOI from the bulk technology. The results show that the SOI has less substrate coupling when no guard band is used, up to a certain frequency that is highly dependent of the chip structure. When a guard band is introduced in one of the analyzed test structures, the bulk resulted in much higher attenuation compared with SOI. An on-chip measurement circuit aiming at measuring simultaneous switching noise has also been designed in a 0.13 µ SOI process.
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| 2. |
- Elbornsson, Jonas, et al.
(författare)
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Analysis of Mismatch Effects in Randomly Interleaved A/D Converter System
- 2005
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Ingår i: IEEE Transactions on Circuits And Systems Part I. - : Institute of Electrical and Electronics Engineers (IEEE). - 1057-7122 .- 1558-1268. ; 52:3, s. 465-476
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Tidskriftsartikel (refereegranskat)abstract
- To significantly increase the sampling rate of an A/D converter (ADC), a time interleaved ADC system is a good option. The drawback of a time interleaved ADC system is that the ADCs are not exactly identical due to errors in the manufacturing process. This means that time, gain and offset mismatch errors are introduced in the ADC system. These errors cause non harmonic distortion in the sampled signal. One way to decrease the impact of the mismatch errors is to spread the distortion over a wider frequency range by randomizing the order in which the ADCs are used in the interleaved structure. In this paper we analyze how the spectrum is affected by mismatch errors in a randomly interleaved ADC system. We also discuss how the mismatch errors can be estimated.
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| 3. |
- Engkvist, Inga-Lill, 1950-, et al.
(författare)
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Planera, utforma och driva en återvinningscentral
- 2009
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Bok (populärvet., debatt m.m.)abstract
- Denna bok baserar sig på de forskningsresultat och erfarenheter som kommit fram inom forskningsprogrammet ”Framtidens återvinningscentral” som är ett multidiciplinärt forskningsprogram som drivits vid Linköpings universitet under åren 2002-2007.Boken vänder sig till alla som är involverade vid planering, byggnation, ombyggnation och drift av återvinningscentraler. Dessa kan vara ansvariga inom kommuner, arkitekter, konsulter, arbetsledare på återvinningscentral, skyddsombud, fackliga förtroendemän med flera.
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| 4. |
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| 5. |
- Malmström, Erik, et al.
(författare)
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The importance of fibroblasts in remodelling of the human uterine cervix during pregnancy and parturition.
- 2007
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Ingår i: Molecular Human Reproduction. - : Oxford University Press (OUP). - 1460-2407. ; 13, s. 333-341
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Tidskriftsartikel (refereegranskat)abstract
- It is well established that fibroblasts play a crucial role in pathophysiological extracellular matrix remodelling. The aim of this project is to elucidate their role in normal physiological remodelling. Specifically, the remodelling of the human cervix during pregnancy, resulting in an enabled passage of the child, is used as the model system. Fibroblast cultures were established from cervices of non-pregnant women, women after 36 weeks of pregnancy and women directly after partus. The cells were immunostained and quantified by western blots for differentiation markers. The cultures were screened for cytokine and metalloproteinase production and characterized by global proteome analysis. The cell cultures established from partal donors differ significantly from those from non-pregnant donors, which is in accordance with in vivo findings. A decrease in alpha-smooth actin and prolyl-4hydroxylase and an increase in interleukin (IL)-6, IL-8 and matrix metalloproteinases (MMP)-1 and MMP-3 were observed in cultures from partal donors. 2D-gel electrophoresis followed by mass spectrometry showed that the expression of 59 proteins was changed significantly in cultures of partal donors. The regulated proteins are involved in protein kinase C signalling, Ca2+ binding, cytoskeletal organization, angiogenesis and degradation. Our data suggest that remodelling of the human cervix is orchestrated by fibroblasts, which are activated or recruited by the inflammatory processes occurring during the ripening cascade.
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| 6. |
- Ahnesjö, Anders, et al.
(författare)
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Detector response modeling
- 2009
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Patent (populärvet., debatt m.m.)abstract
- A detector response correction arrangement and method is proposed for online determination of correction factors for arbitrary positions from arbitrary incident fluence distributions. As modern radiotherapy utilizes more of the available degrees of freedom of radiation machines, dosimetry has to be able to present reliable measurements for all these degrees of freedom. To determine correction factors online during measurement, Monte Carlo technique is used to precalculate fluence pencil kernels from a monodirectional beam to fully describe the particle fluence in an irradiated medium. Assuming that the particle fluence is not significantly altered by the introduction of a small detector volume, the fluence pencil kernels (212) can be integrated (214), and correction factors (216) determined, e.g. by Cavity Theory, in different positions for the detector material.
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| 7. |
- Alami, Jones, et al.
(författare)
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Phase tailoring of Ta thin films by highly ionized pulsed magnetron sputtering
- 2007
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Ingår i: Thin Solid Films. - : Elsevier. - 0040-6090 .- 1879-2731. ; 515:7-8, s. 3434-3438
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Tidskriftsartikel (refereegranskat)abstract
- Ta thin films were grown on Si substrates at different inclination angles with respect to the sputter source using high power impulse magnetron sputtering (HIPIMS), an ionized physical vapor deposition technique. The ionization allowed for better control of the energy and directionality of the sputtered species, and consequently for improved properties of the deposited films. Depositions were made on Si substrates with the native oxide intact. The structure of the as deposited films was investigated using X-ray diffraction, while a four-point probe setup was used to measure the resistivity. A substrate bias process-window for growth of bcc-Ta was observed. However, the process-window position changed with changing inclination angles of the substrate. The formation of this low-resistivity bcc-phase could be understood in light of the high ion flux from the HIPIMS discharge.
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| 8. |
- Andersson, Magnus, et al.
(författare)
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Structural Dynamics of Light-Driven Proton Pumps
- 2009
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Ingår i: Structure. - : Elsevier BV. - 0969-2126 .- 1878-4186. ; 17:9, s. 1265-1275
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Tidskriftsartikel (refereegranskat)abstract
- Bacteriorhodopsin and proteorhodopsin are simple heptahelical proton pumps containing a retinal chromophore covalently bound to helix G via a protonated Schiff base. Following the absorption of a photon, all-trans retinal is isomerized to a 13-cis conformation, initiating a sequence of conformational changes driving vectorial proton transport. In this study we apply time-resolved wide-angle X-ray scattering to visualize in real time the helical motions associated with proton pumping by bacteriorhodopsin and proteorhodopsin. Our results establish that three conformational states are required to describe their photocycles. Significant motions of the cytoplasmic half of helix F and the extracellular half of helix C are observed prior to the primary proton transfer event, which increase in amplitude following proton transfer. These results both simplify the structural description to emerge from intermediate trapping studies of bacteriorhodopsin and reveal shared dynamical principles for proton pumping.
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| 9. |
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| 10. |
- Cerne, Olof, et al.
(författare)
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Rena Turen - Utvärdering av miljöanpassade bränslen i fritidsbåtar
- 2008
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Fritidsbåtars avgasutsläpp till vatten och luft har undersökts. Tre inombords dieselmotorer och en 2-takts utombordsmotor har testats med standardbränslen och miljöanpassade bränslen. För dieselmotorerna användes standarddiesel, syntetisk diesel (GTL), rapsmetylester (RME), jetbränsle samt olika blandningar av diesel och RME. 2-taktsmotorn testades med standardbensin, alkylatbensin samt etanol (E85). För testerna med etanol krävdes en konvertering av motorn. Ekotoxikologiska tester har gjorts på kylvatten från dieselmotorer och på vatten som bubblats med avgaser från utombordsmotor. GTL gav något lägre utsläpp till luft av partiklar, kolväten, kolmonoxid och kväveoxider än vad standarddiesel gav. RME gav betydligt lägre halt partiklar och kolväten men något mer kväveoxider. Kylvatten från en inombords dieselmotor var giftigt mot sebrafiskar och kräftdjur. kylvatten. GTL och RME gav ett kylvatten som var betydligt mindre giftigt mot sebrafiskar än vad standarddiesel gav. PAH-utsläppen till vatten från dieselmotorerna var 10-20 mg per liter diesel. Utsläppen från de traditionella 2-takts utombordarna dominerar tydligt utsläppsmängderna. Standardbensin gav höga halter av miljö- och hälsofarliga ämnen, bland annat bensen, PAHer och formaldehyd. En liter bensin gav cirka 2,3 g PAH. Alkylatbensin och etanolbränslet E85 gav betydligt mindre utsläpp. Sveriges fritidsbåtar släpper uppskattningsvis ut 75 ton PAH per år. Avgasvatten från utombordare var giftigt för bakterier, alger och kräftdjur. Standardbensin var giftigast för bakterier och kräftdjur. Alkylatbensin var mindre giftig mot bakterier och kräftdjur. För alger var skillnaden liten mellan standardbensin, alkylatbensin och E85. Merparten av fritidsbåtarnas förbrukning av bensin och diesel sker i kustvatten. Trots det kan det vara i sjöar och mindre vattendrag som effekterna av utsläppen är störst. Traditionella tvåtaktare används även i sjöar som utnyttjas till dricksvatten och fiske av matfisk och kräftor. Studien visar relativt stor miljöpåverkan från den traditionella 2-takts utombordare som undersökts. Resultaten indikerar att alkylatbensin ger betydligt mindre risker. E85 kan också vara ett alternativ till standardbensin. Det går utmärkt att köra en utombordare på E85, men det kräver en konvertering av motorn vilket gör att det inte är aktuellt för flertalet användare. De observerade emissionerna av aldehyder ger anledning till att studera detta närmare. Det verkar som om bensin ger mer formaldehyd än etanol, medan etanol ger mer acetaldehyd, men testerna är inte tillräckligt omfattande för att göra en fullständig bedömning. Projektet föreslår ytterligare undersökningar bland annat av kylvatten från inombordare och aldehyder i avgaser från utombordare
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