Key words galaxies: magnetic fields – magnetohydrodynamics (MHD) – turbulence We summarize the current state of the long term discussion about the saturation mechanisms associated with rapid growth of small-scale magnetic field, that operate in large-scale galactic dynamos, and related problems with magnetic helicity conservation. Our general conclusion is that, taking into account magnetic hel...

Cross relaxation between macromolecular protons and water protons is known to be important in biologic tissue. In magnetic resonance (MR) imaging sequences, selective saturation of the characteristically short T2 macromolecular proton pool can produce contrast called magnetization transfer contrast, based on the cross-relaxation process. Selective saturation can be achieved with continuous wave...

Magnetic hysteresis is probably one of the most fascinating and complex physical phenomena. While (dynamically) quasi-linear magnetic materials are the basis of many practical applications (linear inductors, power transformer etc.), there exist several examples wherein the exploitation of non-linear magnetic materials is central to obtaining good signal detection performance. An example of such...

The distribution of magnetic moments in a ferromagnetic crystal is investigated. It is found that such a crystal consists of elementary layers magnetized to saturation. The width of these layers is determined. In an external magnetic field, the boundaries between these layers move; the velocity of this propagation is determined. The magnetic permeability in a periodical field parallel and perpe...

Nuclear magnetic resonance cross-relaxation spectroscopy maps the proton solidstate NMR spectrum onto the proton water NMR signal of aqueous heterogeneous materials ( Z-3). Application of a relatively long, low-intensity RF pulse, off resonance from the water Larmor frequency but within the linewidth of the solid, partially saturates the nuclear magnetism of the solid protons. Magnetic cross re...

The homogenization design method (HDM) is extended to obtain an optimal topology of magnetic fields. This is accomplished by maximizing the magnetic mean compliance in a given region of the device. HDM is applied to a three-dimensional case, taking into account the saturation effect of the material. Results show that HDM is valid to maximize the vector potential and the magnetic energy. This me...

A Ni–Mn–Ga single crystal with a phase transformation temperature above 350 K is investigated. The material demonstrates a magnetic field-induced strain (MFIS) of 7% at room temperature and of 4.2% at 350 K. The temperature dependence of the magnetic anisotropy and of the saturation magnetization has been studied in detail. At 350 K a maximum magnetic stress of 1.6 MPa and a twinning stress of ...

We report, for the first time, a multimodal, oxidation-responsive contrast agent for magnetic resonance imaging and photoacoustic imaging that uses the differences in the properties between Eu in the +2 and +3 oxidation states. The enhancement of contrast in T1-weighted magnetic resonance and photoacoustic imaging was observed in the +2 but not in the +3 oxidation state, and the complex is a kn...