Mechanical oscillations of magnetic strips under the influence of external field

This is the final version of the article. Available from EDP Sciences via the DOI in this record.JEMS 2012 – Joint European Magnetic SymposiaBy application of a magnetic field on an amorphous metallic strip, the orientation of magnetization of Weiss domains can be changed. When the strip changes its length, this effect is called magnetostriction. We simulate this effect using a finite element method. In particular we calculate the change of the mechanical resonance frequency of a magnetic platelet as a function of the applied field. This gives a quantitative model of the influence of the applied magnetic field on the effective Young's Modulus of the material. © 2013 Owned by the authors, published by EDP Sciences

On the limits of coercivity in permanent magnets

This is the final version. Available from AIP Publishing via the DOI in this recordThe maximum coercivity that can be achieved for a given hard magnetic alloy is estimated by computing the energy barrier for the nucleation of a reversed domain in an idealized microstructure without any structural defects and without any soft magnetic secondary phases. For Sm1–zZrz(Fe1–yCoy)12–xTix based alloys, which are considered an alternative to Nd2Fe14B magnets with a lower rare-earth content, the coercive field of a small magnetic cube is reduced to 60% of the anisotropy field at room temperature and to 50% of the anisotropy field at elevated temperature (473 K). This decrease of the coercive field is caused by misorientation, demagnetizing fields, and thermal fluctuations.Austrian Science Fund (FWF)New Energy and Industrial Technology Development Organization (NEDO

Fast stray field computation on tensor grids

A direct integration algorithm is described to compute the magnetostatic field and energy for given magnetization distributions on not necessarily uniform tensor grids. We use an analytically-based tensor approximation approach for function-related tensors, which reduces calculations to multilinear algebra operations. The algorithm scales with N^(4/3) for N computational cells used and with N^(2/3) (sublinear) when magnetization is given in canonical tensor format. In the final section we confirm our theoretical results concerning computing times and accuracy by means of numerical examples.Comment: 16 pages, 1 figure, submitted to the Journal of Computational Physic

Physics-informed machine learning combining experiment and simulation for the design of neodymium-iron-boron permanent magnets with reduced critical-elements content

Rare-earth elements like neodymium, terbium and dysprosium are crucial to the performance of permanent magnets used in various green-energy technologies like hybrid or electric cars. To address the supply risk of those elements, we applied machine-learning techniques to design magnetic materials with reduced neodymium content and without terbium and dysprosium. However, the performance of the magnet intended to be used in electric motors should be preserved. We developed machine-learning methods that assist materials design by integrating physical models to bridge the gap between length scales, from atomistic to the micrometer-sized granular microstructure of neodymium-iron-boron permanent magnets. Through data assimilation, we combined data from experiments and simulations to build machine-learning models which we used to optimize the chemical composition and the microstructure of the magnet. We applied techniques that help to understand and interpret the results of machine learning predictions. The variables importance shows how the main design variables influence the magnetic properties. High-throughput measurements on compositionally graded sputtered films are a systematic way to generate data for machine data analysis. Using the machine learning models we show how high-performance, Nd-lean magnets can be realized

On the limits of coercivity in permanent magnets

The maximum coercivity that can be achieved for a given hard magnetic alloy is estimated by computing the energy barrier for the nucleation of a reversed domain in an idealized microstructure without any structural defects and without any soft magnetic secondary phases. For Sm1-zZrz(Fe1-yCoy)12-xTix based alloys, which are considered an alternative to Nd2Fe14B magnets with a lower rare-earth content, the coercive field of a small magnetic cube is reduced to 60% of the anisotropy field at room temperature and to 50% of the anisotropy field at elevated temperature (473 K). This decrease of the coercive field is caused by misorientation, demagnetizing fields, and thermal fluctuations

YangZheng XiaoJi exerts anti-tumour growth effects by antagonising the effects of HGF and its receptor, cMET, in human lung cancer cells

BACKGROUND: Hepatocyte growth factor (HGF) is a cytokine that has a profound effect on cancer cells by stimulating migration and invasion and acting as an angiogenic factor. In lung cancer, the factor also plays a pivotal role and is linked to a poor outcome in patients. In particular, HGF is known to work in combination with EGF on lung cancer cells. In the present study, we investigated the effect of a traditional Chinese medicine reported in cancer therapies, namely YangZheng XiaoJi (YZXJ) on lung cancer and on HGF mediated migration and invasion of lung cancer cells. METHODS: Human lung cancer cells, SKMES1 and A549 were used in the study. An extract from the medicine was used. Cell migration was investigated using the EVOS and by ECIS. Cell–matrix adhesion and in vitro invasion were assessed. In vivo growth of lung cancer was tested using an in vivo xenograft tumour model and activation of the HGF receptor in lung tumours by an immunofluorescence method. RESULTS: Both lung cancer cells increased their migration in response to HGF and responded to YZXJ by reducing their speed of migration. YZXJ markedly reduced the migration and in vitro invasiveness induced by HGF. It worked synergistically with PHA665752 and SU11274, HGF receptor inhibitors on the lung cancer cells both on HGF receptor activation and on cell functions. A combination of HGF and EGF resulted in a greater increase in cell migration, which was similarly inhibited by YZXJ, and in combination with the HGF receptor and EGF receptor inhibitors. In vivo, YZXJ reduced the rate of tumour growth and potentiated the effects of PHA665752 on tumour growth. It was further revealed that YZXJ significantly reduced the degree of phosphorylation of the HGF receptor in lung tumours. CONCLUSION: YZXJ has a significant role in reducing the migration, invasion and in vivo tumour growth of lung cancer and acts to inhibit the migratory and invasive effects induced by HGF and indeed by HGF/EGF. This effect is likely attributed to the inhibition of the HGF receptor activation. These results indicate that YZXJ has a therapeutic role in lung cancer and that combined strategy with methods to block HGF and EGF should be considered. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12967-015-0639-1) contains supplementary material, which is available to authorized users

Modelling and simulation of processes in microfluidic devices for biomedical applications

AbstractWe investigate a mathematical model describing the flow of a liquid in a microchannel. The model incorporates immersed objects in the fluid as well as fixed obstacles and boundaries of the microchannel. Objects can have different elastic properties, including solid objects and deformable objects. The flow description accounts for all types of mechanical interactions: fluid–object, object–object, fluid–walls, and object–walls interactions