Røntgen og Neutronspredning
Vores forskning er tæt knyttet til brugen af store forskningsfaciliteter til fremstilling af neutron- og røntgenstråling. Dette inkluderer den nye synchrotron-røntgenkilde MAX-IV og den kommende neutronkilde ESS, begge placeret i Lund (S). Med disse kilder, og vores tilsvarende laboratorieopstillinger, fx. via CXC, studerer vi en lang række hårde og bløde materialer.
Vores tværfaglige aktiviteter strækker sig fra studier af strukturen af polymerer, over dynamik af hydrogen i komplekse biofysiske systemer, til forståelsen af hvordan kvantemekanikken påvirker egenskaberne af materialer som magneter og superledere.
Vores arbejde kombinerer fremstilling af materialer, eksperimentelle studier med neutroner, røntgen, og andre teknikker, numeriske simulationer, og papir-og-blyant teori. Derudover bidrager vi med konstruktion af instrumenter og software til ESS og MAX-IV.
Sektionen “X-ray and Neutron Science” tæller omkring 40 forskere (fra professor til PhD), som arbejder tæt sammen med andre sektioner på NBI og andre institutter på KU, med røntgen- og neutronfaciliteter rundt om i verden, og andre internationale partnere.
Sektionen holder fællesmøde hver 3-4 uge. Derudover har de individuelle forskningsgrupper deres egne ugentlige møder.
Vores sektion har en stolt tradition for undervisning og projektvejledning. Vi underviser i flere grundkurser på Fysik- og Nanoscience-uddanelserne, vi udbyder kurser i biofysik og faststoffysik, og vi underviser tre kandidatkurser og to PhD kurser indenfor røntgen- og neutronteknikker. Hvert år færdiggør vi omkring 25 Bsc og specialeprojekter, de fleste fra Fysik og Nanoscience.
Som studerende på Niels Bohr Instituttet bliver du undervist af forskere. Undervisernes døre står åbne og du kan blive en del af forskningsgrupperne.
Er du interesseret i en uddannelse inden for faststoffysik? Vil du gerne vide mere om uddannelsens indhold, hvordan det er at læse på Niels Bohr Institutet og hvordan du kan ansøge?
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Forskningen i materialer er en del af et større internationalt samarbejde og omfatter både eksperimentelle og teoretiske metoder.
Bløde materialer
Vi undersøger strukturen af bløde materialer. Et eksempel er kunstige cellemembraner af lipider, et andet polymermaterialer, så som polymersmelter og geler, sammensat af lineære eller forgrenede polymerkæder.
Systemerne studeres med en kombination af røntgen- og neutronteknikker, rheologi og numeriske simuleringer. Vi har her specielt fokus på materialernes dynamik og “self-assembly”.
Vi har også stort fokus på studiet af dynamikken af hydrogen i specifikke polymerer, specielt dem som anvendes til tandfyldninger. Endvidere undersøger vi dynamikken af biologisk bundet vand i levende celler og proteiner.
Magnetisme og superledning
Vi studerer magnetiske materialer, især for at forstå hvilken rolle magnetisme spiller for egenskabene af funktionelle materialer.
Eksempler på dette er:
- a)En vigtig del af vores forskningsprogram handler om at undersøge rollen af magnetisme i de gådefulde høj-temperatur superledere, med en ambition om at forstå mekanismen bag superledning i disse materialer.
- b)“frustrerede” magneter, hvor de magnetiske momenter kan pege mange forskellige veje og energilandskabet derved bliver meget fladt og komplekst, hvilket igen kan føre til helt nye termodynamiske faser;
- c)mange-partikel kvantemekaniske korrelationer (“entanglement”) mellem magnetiske momenter.
The X-ray and Neutron Science section has a range of in-house facilities for structural, solid-state and bio-physical studies. The section apply further to large extend international facilities for synchrotron X-ray and Neutron techniques, and has significant activities within new instrumental design and developement.
The in-house instruments are located within the H.C. Ørsted Institute, in laboratories for magnetism, for X-ray science and for biophysical studies and sample preparation. Several of the instruments are open to be used by external partners from universities as well as from industry. External application is done in terms of joint projecs.
The main instruments comprises:
Investigation of interpenetrating polymer networks for drug delivery under mechanical deformation by Small-Angle X-ray Scattering (SAXS)
The company Biomodics have developed a patented technique to incorporate a hydrogel into silicone rubber, which is widely used for tubing in biomedicine, for example in urinary catheters used in hospitals. The advantage of Biomodics’s material is that the incorporation of hydrogel prevents the formation of biofilms (germs) and that the material potentially can be used for drug delivery. The LINX (Linking Industry to Neutrons and X-rays) group at NBI is involved in a project with the company in which their materials are studied with small-angle neutron and X-ray scattering (SANS and SAXS). Block copolymer self-assembly under hyperbolic confinement
Numerical simulations reveal a family of hierarchical and chiral multicontinuous network structures self-assembled from a melt blend of Y-shaped ABC and ABD three-miktoarm star terpolymers, se figure below. These mesostructures are among the most topologically complex morphologies identified to date and represent an example of hierarchical ordering within a hyperbolic pattern, a unique mode of soft matter self-assembly. In this project the idea is to implement a simulation setup to investigate the self-assembly of model block copolymers under different hyperbolic constraints, i.e. where the polymer are forced to assemble within a thin curved film.
For more information on the Block copolymer self-assembly under hyperbolic confinement project >>
If you are interested - please contact Jacob Kirkensgaard (jjkk@nbi.ku.dk)
Simulation and experimental study of block copolymers self-assembling under spherical confinement
A rel
atively new, but conceptually simple experimental procedure makes it possible to form spherically confined nano-particles out of block copolymers by a clever evaporation of mixed good and bad solvent for the polymers. A new simulation setup allows to simulate such spherically confined systems of arbitrary mixtures of block copolymers which reproduce existing experimental results for diblock copolymers. In this project the idea is to investigate the effect of confinement on new metal containing diblocks and/or ABC star polymeric systems which in the melt state form many complex structures already.
If you are interested - please contact Jacob Kirkensgaard (jjkk@nbi.ku.dk)
Block copolymer self-assembly under double spherical (shell) nano-confinement
A relatively new, but conceptually simple experimental procedure makes it possible to form spherically confined nano-particles out of block copolymers by a clever evaporation of mixed good and bad solvent for the polymers. A new simulation setup allows to simulate such spherically confined systems of arbitrary mixtures of block copolymers which reproduce existing experimental results for diblock copolymers. In this project the idea is to investigate the effect of such confinement when the polymers at the same time are restricted to move on an inner sphere which could either be a metal nanoparticle or a liquid core. If this is a Master project there is a possibility to expand the project experimentally.
If you are interested - please contact Jacob Kirkensgaard (jjkk@nbi.ku.dk)
Structural characterization of thylakoid membrane stacks
Thylakoid membranes (TM) are a vital part of the photosynthetic machinery in green plants, cyanobacteria and algae as most of the proteins taking part of the light capturing is embedded in this membrane system. TM’s has a very striking organization on mesoscales as they arrange into stacked cylindrical domains, ‘grana’, surrounded by membrane sheets,‘stroma lamellae’, connecting other grana. Ultimately we are interested in the role of this organization in the process of photosynthesis and specifically the structural behavior in the grana stack.
The project will be focused on structural characterization of well-defined TM’s cross-characterized by electron microscopy. This will be done performing detailed measurements using Small-Angle X-ray Scattering (SAXS). There are many possible directions for a project within this field - please come and discuss if interested.
For more information on the Structural characterization of thylakoid membrane stacks project >>
If you are interested - please contact Jacob Kirkensgaard (jjkk@nbi.ku.dk)
Wang-Landau Monte Carlo simulations of single ABC miktoarm star block copolymers
The behavior of single polymer chains under different solvent conditions plays a central role in polymer physics. This is also the case when different chains are combined to form block copolymers. A single homopolymer chain in a so-called bad solvent will collapse to a structureless compact globule minimizing unfavorable contact between the solvent and the monomers. Introducing two kinds of monomers A and B immediately gives rise to a much richer behavior. In particular, micro-phase separation is possible, leading to various interesting internal structures. In this project you will use a Wang-Landau Monte Carlo simulation setup to investigate 3-armed ABC star molecules. The major interest is how confinement within a globule, which in this case is a flexible kind of confinement, affects the resulting morphology.
For more information on the Wang-Landau Monte Carlo simulations of single ABC miktoarm star block copolymers project >>
If you are interested - please contact Jacob Kirkensgaard (jjkk@nbi.ku.dk)
For at se den enkelte forskers publikationer, klik på linket nederst på siden.
For at se alle publikationer Røntgen og Neutronspredningsgruppen >>
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Kim Lefmann, professor |
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Maria Batista, Sekretær |
Staff
| Navn | Titel | |
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| Søg i Navn | Søg i Titel | |
| Als-Nielsen, Jens | Emeritus |
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| Andersen, Brian Møller | Lektor |
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| Kirkensgaard, Jacob Judas Kain | Lektor |
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| Kreisel, Andreas | Adjunkt |
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| Krighaar, Kristine Marie Løfgren | Ph.d.-studerende |
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| Lefmann, Kim | Professor |
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| Lenander, Emma Ynill | Ph.d.-stipendiat |
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| Nunes Bordallo, Heloisa | Lektor |
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| Theodor, Keld | Ingeniørassistent |
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