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182 Uppsatser om Magnetic resonance imaging - Sida 1 av 13

Design och konstruktion av mätuppställning för induktiv mätning av magnetisk spinndynamik

Development in spin dynamic occurs in the whole world because of therising demands on fast electronic storage for example hard drivesand RAM (Random Access Memory). Measuring the spin resonance of amaterial gives you the insight of the theoretical speed for amagnetic memory. This means the maximum storage speed is below thefirst resonance. All magnetic materials have different propertiesthat will inflict the resonance frequency which brings that theconstructors of memories need to know which magnetic material theywill use to obtain best results. In the market for normal users themaximum storage speed in a RAM memory is 1.6 GHz.

Magnetresonanstomografi, MRI : Litteraturstudie och simulering

Magnetiskresonanstomografi, MRI, är en användbar teknik inom flera områden, i denna uppsats ligger fokus på användning inom medicin. Fysiken som ligger bakom MRI presenteras, som t ex uppdelning av energinivåer och kärnmagnetiskresonans. Uppbyggnad och tekniken som ligger bakom MRI har även studeras. Sedan har det gjorts jämförelse mellan MRI, röntgen och datortomografi. Utöver litteraturstudierna har simulering gjorts. I denna del har en modell för hjärnan byggts i programmet Comsol Multiphysics.

Elektronstrukturbaserad magnetiseringsdynamik

In this project a method used for performing accurate simulations on magnetization dynamics based on constrained field density functional theory has been validated and used for performing computations on a few magnetic materials. The method has been shown to simulate systems consisting of iron well, but there are still problems with simulations of alloys containing both magnetic and non-magnetic materials..

Patienters upplevelse i samband med MR-undersökning.

Magnetic resonance imaging (MRI) is a safe and painless diagnostic method. The patient may become concerned, suffer from anxiety and experience the examination as unpleasant. Detailed information and a good treatment can reduce anxiety and distress for the patient. The purpose of this study was to illuminate the patient?s experiences in connection to MRI, and to describe the patients needs for information and treatment.

Afasi-vänlig information : inför funktionell undersökning av språk med magnetresonanstomografi (fMRI)

Functional Magnetic resonance imaging, fMRI, can be used for analyzing brain activity in subjects performing language tasks. The purpose of this study was to develop aphasia-friendly information adjusted to aphasic subjects participating in fMRI studies. The objectives were to investigate if adjusted information was important for the ability to perform language tasks and if the information could be used for different types of aphasia.Sixteen aphasic subjects participated in the study, six of these underwent fMRI. The participants varied in grade and type of aphasia. They had Swedish as their native language and were aged between 26 and 89, mean 57.

Visualisering av hovleden hos häst med magnetresonanstomografi

Lameness localized to the hoof is a common problem in horses. Magnetic resonance imaging (MRI) as a diagnostic tool is becoming more common and is well suited for examination of the distal limb and the hoof capsule. Today there are two different methods of MRI where in one the horse is under general anesthesia and in the other the horse is standing and only sedated. In this study we have compared the visualization of the distal interphalangeal joint using these two methods in two different groups of horses with unknown clinical problems referred to two different equine hospitals. The width of the joint structures including thickness of joint cartilage and joint fluid and also the width of the dorsal pouch of the distal interphalangeal joint were measured.

Magnetisk separering av malmpebbles i KA3 - mekaniska konceptförslag : Magnetic separation of ore in KA3 - conceptual design propositions

This has been a thesis work for an bachelor degree at Umeå university. The work has been done at LKAB?s facilities in Kiruna and its main purpose has been to investigate and construct some conceptual designs for replacing a screen with magnetic separation in KA3 concentrator plant. First all information available about magnetic separation was gathered and studies of magnetic separation at the sorting plant and studies of the plant KA3 was conducted. Companies that manufacture magnetic separators were contacted.

Lönsamhetsbedömning av utökad MR-kapacitet på Karolinska Universitetssjukhuset

This thesis analyses how a radiology department at the largest hospital in Sweden, Karolinska University Hospital, most profitably could expand its capacity for investigating cancer patients using Magnetic resonance imaging (MRI). The queues today for patients waiting to be scanned are long, which delays the start of cancer treatments. Meanwhile the hospital has a budget deficit of half a billion SEK, which make any expansion hard. In this thesis we evaluate the alternatives of investing in new machinery; utilize the current machinery better by using them more days annually or through a shift work system. Finally we evaluate a combination of these.

Rekonditionering av IBC

This report describes how the system may be exposed to oscillations and how this can lead to resonance. Resonance is a phenomenon that occurs when a system is affected by external periodic oscillations with frequencies close to the system's natural frequencies. Structures subjected to resonance can risk great damage and destruction, why resonance is something that is important to take into account when designing structures. Alternative ways to counteract resonance is to supply damping in the system. Damping means that the resonance decreases instead of letting the amplitude increase.The report discusses some examples on constructions that have experienced the effect of resonance.

Standardisering av dragarinstallation

This report describes how the system may be exposed to oscillations and how this can lead to resonance. Resonance is a phenomenon that occurs when a system is affected by external periodic oscillations with frequencies close to the system's natural frequencies. Structures subjected to resonance can risk great damage and destruction, why resonance is something that is important to take into account when designing structures. Alternative ways to counteract resonance is to supply damping in the system. Damping means that the resonance decreases instead of letting the amplitude increase.The report discusses some examples on constructions that have experienced the effect of resonance.

Ett alternativt lågtrycksbränslesystem

This report describes how the system may be exposed to oscillations and how this can lead to resonance. Resonance is a phenomenon that occurs when a system is affected by external periodic oscillations with frequencies close to the system's natural frequencies. Structures subjected to resonance can risk great damage and destruction, why resonance is something that is important to take into account when designing structures. Alternative ways to counteract resonance is to supply damping in the system. Damping means that the resonance decreases instead of letting the amplitude increase.The report discusses some examples on constructions that have experienced the effect of resonance.

Konstruktion av instrument för dragprov på nervceller

This report describes how the system may be exposed to oscillations and how this can lead to resonance. Resonance is a phenomenon that occurs when a system is affected by external periodic oscillations with frequencies close to the system's natural frequencies. Structures subjected to resonance can risk great damage and destruction, why resonance is something that is important to take into account when designing structures. Alternative ways to counteract resonance is to supply damping in the system. Damping means that the resonance decreases instead of letting the amplitude increase.The report discusses some examples on constructions that have experienced the effect of resonance.

Resonans

This report describes how the system may be exposed to oscillations and how this can lead to resonance. Resonance is a phenomenon that occurs when a system is affected by external periodic oscillations with frequencies close to the system's natural frequencies. Structures subjected to resonance can risk great damage and destruction, why resonance is something that is important to take into account when designing structures. Alternative ways to counteract resonance is to supply damping in the system. Damping means that the resonance decreases instead of letting the amplitude increase.The report discusses some examples on constructions that have experienced the effect of resonance.

Temperaturens, kadaverålderns och radiopulssekvensens betydelse för bildkvaliteten vid magnetresonanstomografi av tarsus hos häst

Magnetic resonance imaging (MRI) has the potential to be used for the diagnosis and study of osteoarthrosis in the equine tarsal region. In the development of new diagnostic MRI techniques cadaver specimens are often used. To allow the use of cadaver legs for these types of studies it is important to know the effect of time after death on the MRI image. Since the relaxation times are temperature dependent, it is interesting to examine whether the time after death and the temperature of the cadaver may play a role in the image appearance and quality. The radio pulse sequences that show the different types of tissues are also important to know when pathological evaluation with MRI is used.

Variationer i normal språklig förmåga hos vuxna jämfört med neural aktivitet

Since the brain is an important prerequisite for human language there is a great interest to gain more knowledge about healthy brain activity during language mediated communication. This study examines variations in high level language ability relating to demographic factors like gender and age and relates language ability to neural activity.Eighteen individuals in ages between 22 and 64 were included and divided into groups in relation to gender and age. The material used to assess language ability was derived from Testbatteri för Bedömning av Subtila Språkstörningar (Laakso, Brunnegård, Hartelius & Ahlsén, 2000), Swedish Lexical Decision Test (Almkvist, Adveen, Henning & Tallberg, 2007) and a reading test (Högskoleprovet). The results were correlated with measured brain activity using functional Magnetic resonance imaging (fMRI) and language paradigms. ANOVA was applied to discover possible demographic variances in language ability as well as in brain activity.The results showed no significant differences in language ability.

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