758 research outputs found

    Comment on ``Reduction of static field equation of Faddeev model to first order PDE'', arXiv:0707.2207

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    The authors of the article Phys. Lett. B 652 (2007) 384, (arXiv:0707.2207), propose an interesting method to solve the Faddeev model by reducing it to a set of first order PDEs. They first construct a vectorial quantity α\bm \alpha , depending on the original field and its first derivatives, in terms of which the field equations reduce to a linear first order equation. Then they find vectors α1\bm \alpha_1 and α2\bm \alpha_2 which identically obey this linear first order equation. The last step consists in the identification of the αi\bm \alpha_i with the original α\bm \alpha as a function of the original field. Unfortunately, the derivation of this last step in the paper cited above contains an error which invalidates most of its results

    Twinning phenomena along and beyond the bain path

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    Twinning is a phenomenon that occurs, e.g., during deformation, martensitic transformation and film growth. The present study shows that the crystallography of twinning can be described by two twinning modes along the complete Bain transformation path and beyond connecting body-centered and face-centered cubic structures. To probe this concept, we used strained epitaxial films of the Fe-Pd magnetic shape memory system. As the substrate acts as an absolute reference frame, we could show by pole figure measurements that all observed twinning can be a body-centered and face-centered cubic twinning mode. This continuously transforms towards identity when approaching the complementary structure

    Eosinophilic Heart Disease: A Case Report and Review of Literature (Poster).

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    Hypereosinophilic syndrome is a rare condition and present with nonspecific symptoms. Literature is limited. The involvement of myocardium has some peculiar features. Use of different diagnostic techniques such as echocardiography and MRI can help make the diagnosis of hypereosinophilic syndrome. We are presenting a case with review of the topic

    Promoting abnormal grain growth in Fe-based shape memory alloys through compositional adjustments

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    Iron-based shape memory alloys are promising candidates for large-scale structural applications due to their cost efficiency and the possibility of using conventional processing routes from the steel industry. However, recently developed alloy systems like Fe–Mn–Al–Ni suffer from low recoverability if the grains do not completely cover the sample cross-section. To overcome this issue, here we show that small amounts of titanium added to Fe–Mn–Al–Ni significantly enhance abnormal grain growth due to a considerable refinement of the subgrain sizes, whereas small amounts of chromium lead to a strong inhibition of abnormal grain growth. By tailoring and promoting abnormal grain growth it is possible to obtain very large single crystalline bars. We expect that the findings of the present study regarding the elementary mechanisms of abnormal grain growth and the role of chemical composition can be applied to tailor other alloy systems with similar microstructural features

    Photofission fragment characteristics of 234, 238U and 232Th in the barrier region

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    The bremstrahlung induced fission of 234, 238U and 232Th has been studied at the superconducting Darmstadt linear accelerator (SDALINAC) in the excitation energy region close to the fission barrier. In this contribution results on the fission fragment mass, total kinetic energy (TKE) and angular distributions will be presented. Fission fragment mass and TKE distributions from 234U were studied for the first time in this energy region. The results have been analyzed in terms of fission modes and a dominant yield of the mass asymmetric standard-2 mode was found in all studied nuclei. No strong dependence of the fission mode weights on the excitation energy of the compound nucleus were found. Correlations between mass, TKE and angular distributions have been investigated in 234U and 232Th. A correlation in form of an increased anisotropy for far-asymmetric masses and low TKE were found in both fissioning systems. A possible interpretation of this correlation in terms of fission modes is discussed
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