SCIENTIFIC-ORGANIZATIVE BASES OF THE COLLABORATION IN RENAL TRANSPLANTATION WITH THE INTERNATIONAL SYSTEM `INTERTRANSPLANT"

No abstrac

Magnetically-induced electric polarization in an organo-metallic magnet

The coupling between magnetic order and ferroelectricity has been under intense investigation in a wide range of transition-metal oxides. The strongest coupling is obtained in so-called magnetically-induced multiferroics where ferroelectricity arises directly from magnetic order that breaks inversion symmetry. However, it has been difficult to find non-oxide based materials in which these effects occur. Here we present a study of copper dimethyl sulfoxide dichloride (CDC), an organo-metallic quantum magnet containing $S = 1/2$ Cu spins, in which electric polarization arises from non-collinear magnetic order. We show that the electric polarization can be switched in a stunning hysteretic fashion. Because the magnetic order in CDC is mediated by large organic molecules, our study shows that magnetoelectric interactions can exist in this important class of materials, opening the road to designing magnetoelectrics and multiferroics using large molecules as building blocks. Further, we demonstrate that CDC undergoes a magnetoelectric quantum phase transition where both ferroelectric and magnetic order emerge simultaneously as a function of magnetic field at very low temperatures

On the extreme variants of nuclear fusion realization

The canonic reaction of helium synthesis as a result of deuterium and tritium interaction can take place both in high-temperature and low-temperature variants. In both cases, the nuclei draw together so closely that Coulomb’s barrier becomes enough transparent for tunneling. In the case of high-temperature synthesis the energy of chaotic thermal motion is needed to overcome the energy of electrostatic repulsion of «bare» nuclei. As a contrary, in the low-temperature variant, when deuterium and tritium nuclei replace protons in partially ionized hydrogen molecule, and negatively charged μ-meson replaces the only electron, electromagnetic interaction of nuclei with μ-meson provides nuclei approach each other to the critical distance of Rс ≈ 5 ∙ 10–13 m. A hypothesis on appearance of intermedium quasi-molecular states (IQS) when negatively charged ions collide is formulated. It is supposed that in such states the nuclei can draw together due to effective attraction to the group of negatively charged electrons having higher mass and charge as compared with individual electron. The value Rс ≈ 5 ∙ 10–13 m guarantees the tunneling only for light nuclei; therefore, the focus is made on ions’ collision with α-clustered nuclei (having compositions divisible to α-particles compositions). It is expected that the new nuclei synthesis will take place in the presence of oncoming tunneling of relatively weakly connected α-particles from α-clustered nuclei. For IQS formation, the energy acquired by colliding ions in external fields has to be comparable with the energy of their entire ionization. It was shown that the energies (not exceeding 1 keV) of oxygen ions in experiments with electrolysis of water, were accompanied by appearance of mainly carbon, silicon and iron, which meet this condition. These facts testify for the existence of IQS that have to be considered as one of the necessary conditions of low-energy nuclear reactions. In the Conclusion the program of further research is briefly stated. © 2017, Institute for Metals Superplasticity Problems of Russian Academy of Sciences. All rights reserved

Hall coefficient and Hc2 in underdoped LaFeAsO0.95F0.05

The electrical resistivity and Hall coefficient of LaFeAsO0.95F0.05 polycrystalline samples were measured in pulsed magnetic fields up to m0H = 60 T from room temperature to 1.5 K. The resistance of the normal state shows a negative temperature coefficient (dr/dT < 0) below 70 K for this composition, indicating insulating ground state in underdoped LaFeAsO system in contrast to heavily doped compound. The charge carrier density obtained from Hall effect can be described as constant plus a thermally activated term with an energy gap DE = 630 K. Upper critical field, Hc2, estimated from resistivity measurements, exceeds 75 T with zero-field Tc = 26.3 K, suggesting an unconventional nature for superconductivity.Comment: 12 pages and 4 figure

Anisotropy Reversal of the Upper Critical Field at Low Temperatures and Spin-Locked Superconductivity in K2Cr3As3

We report the first measurements of the anisotropic upper critical field $H_{c2}(T)$ for K$_{2}$Cr$_{3}$As$_{3}$ single crystals up to 60 T and $T > 0.6$ K. Our results show that the upper critical field parallel to the Cr chains, $H_{c2}^\parallel (T)$, exhibits a paramagnetically-limited behavior, whereas the shape of the $H_{c2}^\perp (T)$ curve (perpendicular to the Cr chains) has no evidence of paramagnetic effects. As a result, the curves $H_{c2}^\perp (T)$ and $H_{c2}^\parallel(T)$ cross at $T\approx 4$ K, so that the anisotropy parameter $\gamma_H(T)=H_{c2}^\perp/H_{c2}^\parallel (T)$ increases from $\gamma_H(T_c)\approx 0.35$ near $T_c$ to $\gamma_H(0)\approx 1.7$ at 0.6 K. This behavior of $H_{c2}^\|(T)$ is inconsistent with triplet superconductivity but suggests a form of singlet superconductivity with the electron spins locked onto the direction of Cr chains

A model for intermediate quasi-molecular state and variants of chemical element synthesis

In the present work, the simplest quasi-classic model of intermediate quasi-molecular state (IQS) is discussed. From the one hand, the model is based upon Bohr’s idea about a binding electron orbit of hydrogen molecule having a round form with the orbital plane orthogonal to the section connecting the nuclei. From the other hand, the model permits coupling of electrons (with opposite spins) owing to non-potential contact interaction that had been introduced in hadronic mechanics of Santilli. In order to underline the specifics of the results of such interactions, term “isoparticles” is used in hadronic mechanics. Using a pair of bivalent oxygen ions, it is shown that the simplest model allows drawing the nuclei together until critical distances Rc ≈ 10-13 m. In the discussion of the results, an additional possibility of element synthesis for IQS is noted. This possibility is connected with exchange of virtual isopositron-isoelectron pairs between the near-coming nuclei. The upper level of such interaction radius [Rint]max corresponds to Rc ≈ 10-13 m in the case of exchange of virtual positroniums (with rest energy ≈ 1 MeV), while the lower level [Rint]min ≈ 10−15 m is realized in the case of virtual π0-mesons interchange. As soon as in hadronic mechanics π0-meson is interpreted as a bonded state of isopositron and isoelectron (with rest energy ≈ 135 MeV), the offered mechanism of exchange naturally allows the existence of virtual pairs with energies ε in the interval 1 MeV < ε < 135 MeV. Therefore, by achievement of IQS, the channel for new elements synthesis opens and does not require decomposition of the initial nuclei till α-particles with their following synthesis at opposing motion towards common center of attraction. © 2018, Institute for Metals Superplasticity Problems of Russian Academy of Sciences. All Rights reserved.В данной работе рассматривается простейшая квазиклассическая модель промежуточного квазимолекулярного состояния (ПКС). С одной стороны, модель базируется на идее Бора о связующей электронной орбите молекулы водорода в форме окружности с плоскостью орбиты, ортогональной отрезку, соединяющему ядра. С другой стороны, в модели допускается спаривание электронов (с противоположными спинами) за счет непотенциального контактного взаимодействия, которое было введено в адронной механике Сантилли. Чтобы подчеркнуть специфику результатов подобных взаимодействий, в адронной механике используется термин изочастицы. На примере столкновения пары двухвалентных ионов кислорода показано, что простейшая модель ПКС допускает сближение ядер до критических расстояний Rc≈10−13 м. При обсуждении результатов отмечается дополнительная для ПКС возможность синтеза элементов. Эта возможность заключается в обмене сближающихся ядер виртуальными изопозитрон-изоэлектронными парами. Верхняя граница радиуса такого взаимодействия [Rint]max соответствует Rc в случае обмена виртуальными позитрониями (с энергией покоя ≈1 МэВ), тогда как нижняя граница [Rint]min≈10−15 м реализуется при обмене виртуальными π0-мезонами. Поскольку в адронной механике π0-мезон интерпретируется как связанное состояние изопозитрона и изоэлектрона (с энергией покоя ≈135 МэВ), то предлагаемый механизм обмена естественно допуска ет существование виртуальных пар с энергиями ε из интервала 1 МэВ<ε<135 МэВ. Следовательно при достижении ПКС открывается канал для синтеза новых элементов, не требующий распада исходных ядер на α-частицы с последующим их синтезом при встречном движении к общему центру притяжения

Electronic in-plane symmetry breaking at field-tuned quantum criticality in CeRhIn5

Electronic nematics are exotic states of matter where electronic interactions break a rotational symmetry of the underlying lattice, in analogy to the directional alignment without translational order in nematic liquid crystals. Intriguingly such phases appear in the copper- and iron-based superconductors, and their role in establishing high-temperature superconductivity remains an open question. Nematicity may take an active part, cooperating or competing with superconductivity, or may appear accidentally in such systems. Here we present experimental evidence for a phase of nematic character in the heavy fermion superconductor CeRhIn5. We observe a field-induced breaking of the electronic tetragonal symmetry of in the vicinity of an antiferromagnetic (AFM) quantum phase transition at Hc~50T. This phase appears in out-of-plane fields of H*~28T and is characterized by substantial in-plane resistivity anisotropy. The anisotropy can be aligned by a small in-plane field component, with no apparent connection to the underlying crystal structure. Furthermore no anomalies are observed in the magnetic torque, suggesting the absence of metamagnetic transitions in this field range. These observations are indicative of an electronic nematic character of the high field state in CeRhIn5. The appearance of nematic behavior in a phenotypical heavy fermion superconductor highlights the interrelation of nematicity and unconventional superconductivity, suggesting nematicity to be a commonality in such materials