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Identifying valuable features from complex omics data is of great significance for disease diagnosis study. This paper proposes a new feature selection algorithm based on sample network (FS-SN) to mine important information from omics data. The sample network is constructed according to the sample neighbor relationship at the molecular (feature) expression level, and the distinguishing ability of the feature is evaluated based on the topology of the sample network. The sample network established on a feature with a strong discriminating ability tends to have many edges between the same group samples and few edges between the different group samples. At the same time, FS-SN removes redundant features according to the gravitational interaction between features. To show the validation of FS-SN, it was compared on ten public datasets with ERGS, mRMR, ReliefF, ATSD-DN, and INDEED which are efficient in omics data analysis. Experimental results show that FS-SN performed better than the compared methods in accuracy, sensitivity and specificity in most cases. Hence, FS-SN making use of the topology of the sample network is effective for analyzing omics data, it can identify key features that reflect the occurrence and development of diseases, and reveal the underlying biological mechanism. [ABSTRACT FROM AUTHOR]

Vacancies are prevalent and versatile in solid-state physics and materials science. The role of vacancies in strongly correlated materials, however, remains uncultivated until now. Here, we report the discovery of an unprecedented vacancy state forming an extended buckled-honeycomb-vacancy (BHV) ordering in Ir 16 Sb 18. Superconductivity emerges by suppressing the BHV ordering through squeezing of extra Ir atoms into the vacancies or isovalent Rh substitution. The phase diagram on vacancy ordering reveals the superconductivity competes with the BHV ordering. Further theoretical calculations suggest that this ordering originates from a synergistic effect of the vacancy formation energy and Fermi surface nesting with a wave vector of (1/3, 1/3, 0). The buckled structure breaks the crystal inversion symmetry and can mostly suppress the density of states near the Fermi level. The peculiarities of BHV ordering highlight the importance of "correlated vacancies" and may serve as a paradigm for exploring other non-trivial excitations and quantum criticality. [ABSTRACT FROM AUTHOR]

We report superconductive iridium pnictides Ba[sub x]Ir[sub 4]X[sub 12] (X = As and P) with a filled skutterudite structure, demonstrating that Ba filling dramatically alters their electronic properties and induces a nonmetal-tometal transition with increasing the Ba content x. The highest superconducting transition temperatures are 4.8 and 5.6 K observed for Ba[sub x]Ir[sub 4]As[sub 12] and Ba[sub x]Ir[sub 4]P[sub 12], respectively. The superconductivity in Ba[sub x]Ir[sub 4]P[sub 12] can be classified into the Bardeen -- Cooper -- Schrieffer type with intermediate coupling. [ABSTRACT FROM AUTHOR]

Abstract: We report the achievement of transport critical currents in Sr0.6K0.4Fe2As2 wires and tapes with a Tc =34K. The wires and tapes were fabricated through an in situ powder-in-tube process. Silver was used as a chemical addition as well as a sheath material. All the wire and tape samples have shown the ability to transport superconducting current. Critical current density Jc was enhanced upon silver addition, and at 4.2K, a largest Jc of ∼1200A/cm2 (Ic =9A) was achieved for 20% silver added tapes, which is the highest in iron-based wires and tapes so far. The Jc is almost field independent between 1T and 10T, exhibiting a strong vortex pinning. Such a high transport critical current density is attributed to the weak reaction between the silver sheath and the superconducting core, as well as an improved connectivity between grains. We also identify a weak-link behavior from the apparent drop of Jc at low fields and a hysteretic phenomenon. Finally, we found that compared to Fe, Ta and Nb tubes, Ag was the best sheath material for the fabrication of high-performance 122 type pnictide wires and tapes. [Copyright &y& Elsevier]

Abstract: Using one-step solid state reaction method, we have successfully synthesized the superconductor SrFe1− x Ru x As. X-ray diffraction indicates that the material has formed the ThCr2Si2-type structure with a space group I4/mmm. The systematic evolution of the lattice constants demonstrates that the Fe ions are successfully replaced by the Ru. By increasing the doping content of Ru, the spin-density-wave (SDW) transition in the parent compound is suppressed and superconductivity emerges. The maximum superconducting transition temperature is found at 13.5K with the doping level of x =0.7. The temperature dependence of DC magnetization confirms superconducting transitions at around 12K. Our results indicate that similar to non-isoelectronic substitution, isoelectronic substitution contributes to changes in both the carrier concentration and internal pressure, and superconductivity could be induced by isoelectronic substitution. [Copyright &y& Elsevier]

Abstract: Nb-sheathed Sr0.6K0.4Fe2As2 superconducting wires have been fabricated using the powder-in-tube (PIT) method for the first time and the superconducting properties of the wires have been investigated. The transition temperature (T c) of the Sr0.6K0.4Fe2As2 wires is confirmed to be as high as 35.3K. Most importantly, Sr0.6K0.4Fe2As2 wires exhibit a very weak J c-field dependence behavior even the temperature is very close to T c. The upper critical field H c2(0) value can exceed 140T, surpassing those of MgB2 and all the low temperature superconductors. Such high H c2 and superior J c-field performance make the 122 phase SrKFeAs wire conductors a powerful competitor potentially useful in very high field applications. [Copyright &y& Elsevier]

By breaking the restrictions on traditional alloying strategy, the high entropy concept has promoted the exploration of the central area of phase space, thus broadening the horizon of alloy exploitation. This review highlights the marriage of the high entropy concept and van der Waals systems to form a new family of materials category, namely the high entropy van der Waals materials (HEX, HE = high entropy, X = anion clusters) and describes the current issues and next challenges. The design strategy for HEX has integrated the local feature (e.g., composition, spin, and valence states) of structural units in high entropy materials and the holistic degrees of freedom (e.g., stacking, twisting, and intercalating species) in van der Waals materials, and is successfully used for the discovery of high entropy dichalcogenides, phosphorus tri‐chalcogenides, halogens, and MXene. The rich combination and random distribution of the multiple metallic constituents on the nearly regular 2D lattice give rise to a flexible platform to study the correlation features behind a range of selected physical properties, e.g., superconductivity, magnetism, and metal–insulator transition. The deliberate design of structural units and their stacking configuration can also create novel catalysts to enhance their performance in a bunch of chemical reactions. [ABSTRACT FROM AUTHOR]

Highlights: [•] Single crystals of K0.58Fe1.56Se2 were synthesized by a new single step process. [•] The anisotropy of upper critical field along ab-plane and c-axis is about 3.3. [•] High transport Jc of 1.7×104 A/cm2 at 5K has been obtained in K0.58Fe1.56Se2. [ABSTRACT FROM AUTHOR]

Abstract: A critical issue in depressing critical current density in polycrystalline iron pnictides is intrinsic weak-link behavior. Using well established, industrial scalable, deformation processes, we have achieved c-axis aligned grains in powder-in-tube Sr0.6K0.4Fe2As2 tapes. This is followed by a short high-temperature annealing to enhance the connectivity. The resultant Sr1− x K x Fe2As2 superconducting tapes have transport critical current densities exceeding 5000A/cm2 at 4.2K in self field. This advance open up possibilities for fabricating iron-based superconducting tapes capable of carrying high currents. [Copyright &y& Elsevier]

Magnetic topological insulators (TIs), possessing both magnetic order and topological electronic structure, provides an excellent platform to research unusual physical properties. Here, we report a high-pressure study on the anomalous Hall effect of magnetic TI MnSb4Te7 through transports measurements combined with first-principle theoretical calculations. We discover that the ground state of MnSb4Te7 experiences a magnetic phase transition from the A-type antiferromagnetic state to ferromagnetic dominating state at 3.78 GPa, although its crystal sustains a rhombohedral phase under high pressures. The anomalous Hall conductance σxyA is dominated by intrinsic mechanism even after the magnetic phase transition. The results shed light on the intriguing magnetism in MnSb4Te7 and pave the way for further studies of the relationship between topology and magnetism in topological materials. [ABSTRACT FROM AUTHOR]

Kagome materials have been reported to possess abundant and peculiar physical properties, which provide an excellent platform to explore exotic quantum states. We present a discovery of superconductivity in van der Waals material Pd3P2S8 composed of Pd kagome lattice under pressure. Pd3P2S8 displays superconductivity for those pressures where the semiconducting-like temperature dependence of the resistivity turns into a metallic one. Moreover, it is found that the increased pressure results in a gradual enhancement of superconducting transition temperature, which finally reaches 6.83 K at 79.5 GPa. Combining high-pressure x-ray diffraction, Raman spectroscopy and theoretical calculations, our results demonstrate that the observed superconductivity induced by high pressure in Pd3P2S8 is closely related to the formation of amorphous phase, which results from the structural instability due to the enhanced coupling between interlayer Pd and S atoms upon compression. [ABSTRACT FROM AUTHOR]

Searching for functional square lattices in layered superconductor systems offers an explicit clue to modify the electron behavior and find exotic properties. The trigonal SnAs3 structural units in SnAs‐based systems are relatively conformable to distortion, which provides the possibility to achieve structurally topological transformation and higher superconducting transition temperatures. In the present work, the functional As square lattice was realized and activated in Li0.6Sn2As2 and NaSnAs through a topotactic structural transformation of trigonal SnAs3 to square SnAs4 under pressure, resulting in a record‐high Tc among all synthesized SnAs‐based compounds. Meanwhile, the conductive channel transfers from the out‐of‐plane pz orbital to the in‐plane px+py orbitals, facilitating electron hopping within the square 2D lattice and boosting the superconductivity. The reorientation of p‐orbital following a directed local structure transformation provides an effective strategy to modify layered superconducting systems. [ABSTRACT FROM AUTHOR]

Searching for functional square lattices in layered superconductor systems offers an explicit clue to modify the electron behavior and find exotic properties. The trigonal SnAs3 structural units in SnAs‐based systems are relatively conformable to distortion, which provides the possibility to achieve structurally topological transformation and higher superconducting transition temperatures. In the present work, the functional As square lattice was realized and activated in Li0.6Sn2As2 and NaSnAs through a topotactic structural transformation of trigonal SnAs3 to square SnAs4 under pressure, resulting in a record‐high Tc among all synthesized SnAs‐based compounds. Meanwhile, the conductive channel transfers from the out‐of‐plane pz orbital to the in‐plane px+py orbitals, facilitating electron hopping within the square 2D lattice and boosting the superconductivity. The reorientation of p‐orbital following a directed local structure transformation provides an effective strategy to modify layered superconducting systems. [ABSTRACT FROM AUTHOR]

Recently, the hexagonal phase of ternary transition metal pnictides TT'X (T = Zr, Hf; T' = Ru; X = P, As), which are well-known noncentrosymmetric superconductors, were predicted to host nontrivial bulk topology. In this work, we systematically investigate the electronic responses of ZrRuAs to external pressure. At ambient pressure, ZrRuAs show superconductivity with Tc ~ 7.74 K, while a large upper critical field ~ 13.03 T is obtained for ZrRuAs, which is comparable to the weak-coupling Pauli limit. The resistivity of ZrRuAs exhibits a non-monotonic evolution with increasing pressure. The superconducting transition temperature Tc increases with applied pressure and reaches a maximum value of 7.93 K at 2.1 GPa, followed by a decrease. The nontrivial topology is robust and persists up to the high-pressure regime. Considering both robust superconductivity and intriguing topology in this material, our results could contribute to studies of the interplay between topological electronic states and superconductivity. [ABSTRACT FROM AUTHOR]

As a new type of quantum state of matter hosting low energy relativistic quasiparticles, Weyl semimetals (WSMs) have attracted significant attention for scientific community and potential quantum device applications. In this study, we present a comprehensive investigation of the structural, magnetic, and transport properties of noncentrosymmetric R AlSi (R = Sm, Ce), which have been predicted to be new magnetic WSM candidates. Both samples exhibit nonsaturated magnetoresistance, with about 900% and 80% for SmAlSi and CeAlSi, respectively, at temperature of 1.8 K and magnetic field of 9 T. The carrier densities of SmAlSi and CeAlSi exhibit remarkable change around magnetic transition temperatures, signifying that the electronic states are sensitive to the magnetic ordering of rare-earth elements. At low temperatures, SmAlSi reveals prominent Shubnikov-de Haas oscillations associated with the nontrivial Berry phase. High-pressure experiments demonstrate that the magnetic order is robust and survival under high pressure. Our results would yield valuable insights into WSM physics and potentials in applications to next-generation spintronic devices in the R AlSi (R = Sm, Ce) family. [ABSTRACT FROM AUTHOR]

High-entropy alloy (HEA) is an attracting topic raising in materials science and condensed matter physics. Although several types of superconductors have been discovered in HEAs, the critical currents (Jc) of HEA superconductors require further study. Here, we study the current-carrying ability of (TaNb)0.7(HfZrTi)0.5 HEA at various heat treatment conditions. We obtained the high upper critical field and large current carrying ability, which point to the potential applicability of the HEA superconductor under extreme conditions. Interestingly, the fishtail or the second peak effect was found in HEA superconductors, and the position of the vortex pinning force shows a maximum at 0.72 of the reduced field, which is quite different from the cuprates and iron-based high-Tc superconductors. Together with the resistive measurements, the vortex phase diagram is obtained for the HEA superconductor. [ABSTRACT FROM AUTHOR]

We report the synthesis and superconducting properties of a layered cage compound Ba3Rh4Ge16. Similar to Ba3Ir4Ge16, the compound is composed of 2D networks of cage units, formed by noncubic Rhâ€"Ge building blocks, in marked contrast to the reported rattling compounds. The electrical resistivity, magnetization, specific heat capacity, and ÎĽ SR measurements unveiled moderately coupled s-wave superconductivity with a critical temperature T c = 7.0 K, the upper critical field ÎĽ 0 H c2(0) ∼ 2.5 T, the electron-phonon coupling strength λ eâˆ'ph ∼ 0.80, and the Ginzburgâ€"Landau parameter Îş ∼ 7.89. The mass reduction with the substitution of Ir by Rh is believed to be responsible for the enhancement of T c and coupling between the cage and guest atoms. Our results highlight the importance of atomic weight of framework in cage compounds in controlling the λ eâˆ'ph strength and T c. [ABSTRACT FROM AUTHOR]

The development of PIT fabrication process of iron pnictide superconducting wires and tapes has been reviewed. Silver was found to be the best sheath material, since no reaction layer was observed between the silver sheath and the superconducting core. The grain connectivity of iron pnictide wires and tapes has been markedly improved by employing Ag or Pb as dopants. At present, critical current densities in excess of 3750 A/cm^2\ (Ic=37.5\ A) at 4.2 K have been achieved in Ag-sheathed SrKFeAs wires prepared with the above techniques, which is the highest value obtained in iron-based wires and tapes so far. Moreover, Ag-sheathed Sm-1111 superconducting tapes were successfully prepared by PIT method at temperatures as low as \sim900\ ^\circC, instead of commonly used temperatures of \sim1200\ ^\circC. These results demonstrate the feasibility of producing superconducting pnictide composite wires, even grain boundary properties require much more attention. [ABSTRACT FROM AUTHOR]

Abstract: Fe/Ti, Nb, and Ta sheathed SmO0.7F0.3FeAs wires were manufactured using the powder-in-tube method. A comparative study was made of the effect of sheath material on the microstructure and superconducting properties of the SmO0.7F0.3FeAs wires. Among these sheath materials, the penetration depth of Ta into the superconducting core is the largest. There was nearly no difference in the critical transition temperature of the SmO0.7F0.3FeAs wires sheathed with different materials, and the upper critical fields were approximately the same. On the other hand, it was found that Nb-sheathed wires had a higher superconducting current density than the others. Impurities existing in the superconducting core were thought to be one of the most important factors that affected the critical current density of the SmO0.7F0.3FeAs wires. [Copyright &y& Elsevier]

Abstract: The recent discovery of superconductivity in the iron-based superconductors with very high upper critical fields presents a new possibility for practical applications, but fabricating fine-wire is a challenge because of mechanically hard and brittle powders and the toxicity and volatility of arsenic. In this paper, we report the synthesis and the physical characterization of iron pnictide wires and bulks prepared by the powder-in-tube method (PIT). A new class of high-T c iron pnictide composite wires, such as LaFeAsO1− x F x , SmFeAsO1− x F x and Sr1− x K x FeAs, has been fabricated by the in situ PIT technique using Fe, Ta and Nb tubes. Microscopy and X-ray analysis show that the superconducting core is continuous, and retains phase composition after wire drawing and heat treatment. Furthermore, the wires exhibit a very weak J c-field dependence behavior even at high temperatures. The upper critical field H c2(0) value can exceed 100 T, surpassing those of MgB2 and all the low temperature superconductors and indicating a strong potential for applications requiring very high field. These results demonstrate the feasibility of producing superconducting pnictide composite wire. We also applied the one-step PIT method to synthesize the iron-based bulks, due to its convenience and safety. In fact, by using this technique, we have successfully discovered superconductivity at 35K and 15K in Eu0.7Na0.3Fe2As2 and SmCoFeAsO compounds, respectively. These clearly suggest that the one-step PIT technique is unique and versatile and hence can be tailored easily for other rare earth derivatives of novel iron-based superconductors. [Copyright &y& Elsevier]

Kagome lattice, made of corner-sharing triangles, provides an excellent platform for hosting exotic topological quantum states. Here, we systematically studied the magnetic and transport properties of RMn6Sn6 (R = Tb, Dy, Ho) with clean Mn kagome lattice. All the compounds have a collinear ferrimagnetic structure with different easy axis at low temperature. The low-temperature magnetoresistance (MR) is positive and has no tendency to saturate below 7 T, while the MR gradually declines and becomes negative with the increasing temperature. A large intrinsic anomalous Hall conductivity about 250, 40, and 95 Ω−1 cm−1 is observed for TbMn6Sn6, DyMn6Sn6, and HoMn6Sn6, respectively. Our results imply that RMn6Sn6 system is an excellent platform to discover other intimately related topological or quantum phenomena and also tune the electronic and magnetic properties in future studies. [ABSTRACT FROM AUTHOR]

In order to explore the effects of slim cigarette material parameters on benzo[a] pyrene (B[a]P) delivery in mainstream smoke, the uniform design method was used to design the test plan, and the stepwise regression method was used to establish the regression equations between the release of B[a]P and slim cigarette auxiliary material factors, incluUing cigarette paper permeability (X1), tipping paper permeability (X2), plug wrapper permeability (X3), tow specification in the filter (X4). The optimized auxiliary material parameters were verified. The results showed that the sequence of every factor on the B[a]P yield was X3 > X4 > X2 > X1, and all the factors had negative effects on the release of B [ a] P. The order of the influence of each factor or interaction of factors on the target value was as follows:X2X3 >X1X4 > X3² > X4, the positive correlation with the dlivery of B[a] P were X3² and X4, and the ngative correlation with the delivery of B[a]P were X2X3 and X1X4. The optimized auxiliar materal combination for low B[a]P deliver were 100 CU(X1), 800 CU (X2), 26 000 CU (X3), 6.0Y/17 000(X4). Compared with the lowest B[a]P in the expermental group, the predicative value of the B[a]P deliver in mainstream smoke of slim cigarette decreased by 39.3%. [ABSTRACT FROM AUTHOR]

Recently, natural van der Waals heterostructures of (MnBi2Te4)m(Bi2Te3)n have been theoretically predicted and experimentally shown to host tunable magnetic properties and topologically nontrivial surface states. We systematically investigate both the structural and electronic responses of MnBi2Te4 and MnBi4Te7 to external pressure. In addition to the suppression of antiferromagnetic order, MnBi2Te4 is found to undergo a metal–semiconductor–metal transition upon compression. The resistivity of MnBi4Te7 changes dramatically under high pressure and a non-monotonic evolution of ρ (T) is observed. The nontrivial topology is proved to persist before the structural phase transition observed in the high-pressure regime. We find that the bulk and surface states respond differently to pressure, which is consistent with the non-monotonic change of the resistivity. Interestingly, a pressure-induced amorphous state is observed in MnBi2Te4, while two high-pressure phase transitions are revealed in MnBi4Te7. Our combined theoretical and experimental research establishes MnBi2Te4 and MnBi4Te7 as highly tunable magnetic topological insulators, in which phase transitions and new ground states emerge upon compression. [ABSTRACT FROM AUTHOR]

The extremely large magnetoresistance (XMR) in nonmagnetic semimetals has inspired growing interest owing to both intriguing physics and potential applications. We report the results of synchrotron X-ray diffraction and electrical transport measurements on TaAs2 under pressure up to ∼37 GPa, which revealed an anisotropic compression of the unit cell, formation of unusual As-As bonds above 9.5 GPa, and enhancement of metallicity. Interestingly, the MR of TaAs2 under pressure changed gently, which at 1.7 GPa is 96.6% and at 36.6 GPa is still 36.7%. The almost robust MR under pressure could be related to the nearly stable electronic structure unveiled by the ab initio calculations. The discovery would expand the potential use of XMR even under high pressure. [ABSTRACT FROM AUTHOR]

• We found the transport performance of FeSe 0.5 Te 0.5 tapes protected only by the thin silver layer was poor at high background field, while it could be significantly improved by soldering a stabilizing layer. • We investigated the influence of different stabilizing layers on the performance of tapes. • We investigated the influence of soldering temperature on the performance of tapes. The analysis of the influence of different stabilizing layers and solders on the transport current is very necessary for the engineering application of FeSe 0.5 Te 0.5 coated conductors. The soldering temperature and thermal stress caused by cooling from room temperature to liquid helium can affect the critical current values of the superconducting tapes. For this, FeSe 0.5 Te 0.5 coated conductors with four types of stabilizing layers and three types of solders were prepared. The stabilizing layer includes the copper layer with a thickness of 0.02 mm, 0.05 mm, 0.1 mm, and the silver layer with a thickness of 0.1 mm. The solders are respectively Bi 50 Pb 25 Sn 12.5 Cd 12.5 , Bi 51.2 Pb 30.6 Cd 18.2, and Sn 63 Pb 37. The experimental results show that the critical current of the tape encapsulated by the 0.02 mm thick copper layer and Bi 50 Pb 25 Sn 12.5 Cd 12.5 is about 400 A at self-field and about 25 A at 10 T, which is superior to other samples. The details of the fabrication process and performance test results were presented in this paper. [ABSTRACT FROM AUTHOR]

[Display omitted] • Reversible and non-volatile modulation of the resistivity of SmNiO 3 was realized by electrochemical (de)intercalation of Zn2+. • Phase transition of SmNiO 3 modulated by Al3+ was reversible and volatile. • The electronic phase transition of SmNiO 3 was characterized with various techniques. • The structural distortion of SmNiO 3 was identified to be the decisive factor for the resistivity change. Perovskite rare earth nickelates possess the electronic phase transition property that can be harnessed for a multitude of exciting applications. Herein, we report the use of high-valence cations (Zn2+ and Al3+) to reconstruct the electronic band structure of samarium nickelate (SmNiO 3) and realize reversible resistivity modulation. Under positive gate voltage, the resistivity of SmNiO 3 exhibits a colossal increase upon the Zn2+ intercalation and the concurrent electron doping. Under negative gate voltage, the Zn2+ ions are extracted and the resistivity decreases significantly. The resistivity modulation using Zn2+ is non-volatile. Electrochromic behavior is also observed during the Zn2+ insertion and extraction. The electronic phase transition is characterized using various techniques. Moreover, the trivalent Al3+ ions are also investigated as charge carriers to modulate the resistivity of SmNiO 3 in a volatile manner. First-principles density functional theory calculations reveal the effect of electron doping on the electronic band structure. The resistivity change of SmNiO 3 is mainly attributed to the structural distortion induced by electron doping, rather than the Mott-like insulation. This work demonstrates the feasibility of reversible resistivity modulation of SmNiO 3 with the use of high-valence cations under applied voltage, underscoring the potential for applications in novel emerging electronic devices. [ABSTRACT FROM AUTHOR]

The structures and chemical features of layered compounds BaM2Ge4Ch6 (M = Rh, Ir; Ch = S, Se) syndiesized by high-pressure and high-temperature methods have been systematically studied. These compounds crystallize in an orthorhombic phase with space group Pbca (No. 61). These compounds have the remarkable structural feature of M--Ge--Ch pyrite-type building units, stacking with Ba--Ch layers alternatively along the c axis. It is very rare and novel that pyrite-type subunits are the building blocks in layered compounds. Theoretical calculations and experimental results indicate that there are strongly polarized covalent bonds between Ge and Ch atoms, forming heteromolecule-like anions in these compounds. Moreover, Ge atoms in this structure exhibit an unusual valence state ( ~ + l ) due to the tetrahedral coordination environment of Ge atoms along with M and Ch atoms simultaneously. [ABSTRACT FROM AUTHOR]

Abstract: AC susceptibilities (real χ′ and imaginary χ″) of Sr0.6K0.4Fe2As2 (122 type) polycrystalline with Ag addition are analysed by the grained Bean model. A variety of characteristics, double peak in χ″ and shoulder transition in χ′, appear in the model simulation. Comparing the measured χ′ and χ″ with the model allows more clear insight on the polycrystalline structure. Estimated critical current densities J cg and J cℓ of the grain and the link in the iron-based pnictides show that the addition of 20wt.% Ag increases J cℓ 9 times larger. Improvement of intergrain characteristics with Ag addition is clearly indicated. [Copyright &y& Elsevier]

We report the realization of grain alignment in Sn-added Sr1-xKxFe2As2 superconducting tapes with Fe sheath prepared by ex-situ powder-in-tube method. At 4.2 K, high transport critical current densities Jc of 2.5 × 104 A/cm2 (Ic = 180 A) in self-field and 3.5 × 103 A/cm2 (Ic = 25.5 A) in 10 T have been measured. These values are the highest ever reported so far for Fe-based superconducting wires and tapes. We believe the superior Jc in our tape samples are due to well textured grains and strengthened intergrain coupling achieved by Sn addition. Our results demonstrated an encouraging prospect for application of iron based superconductors. [ABSTRACT FROM AUTHOR]

The superconducting Sr0.6K0.4Fe2As2 (122 type) polycrystalline iron-based pnictides with Pb or Ag addition were prepared by a normal PIT method. The critical current densities were investigated by ac inductive (Campbell's) method. It was found that a fairly large critical current density over 10^10\ A/m^2 even at the relatively high temperatures flows locally with the perimeter size similar to the average grain size of the bulk samples, while an extremely low global critical current density of 10^410^6\ A/m^2 flows through the whole sample. Furthermore, a unique history dependence of global critical current density was observed, i.e., it shows a smaller critical current density in the increasing-field process than that in the decreasing-field process. Basing on the experimental results of the penetrating ac magnetic flux profile and the characteristic of ac magnetic field vs. penetration depth, the inter- and intra-granular super-current, the weak-link and the history effect in these materials were discussed. [ABSTRACT FROM AUTHOR]

MgB2 was thought as a promising superconductor used at temperatures around 20 K for cryogen-free magnet. Nanostructure materials were often selected as MgB2 additives due to their high chemical reactivity. In this paper, the mixture of nano-C and nano-SiC was doped to MgB2 bulks and tapes. The co-doping effect of C and SiC on the phase formation, microstructure, and critical current density of MgB2 bulks and tapes were systematically investigated. The mechanisms for the superconducting properties improvement in co-doped MgB2 superconductor was analyzed based on the characterization and measuring results. [ABSTRACT FROM AUTHOR]

Phase-pure polycrystalline Ba0.6K0.4+xFe2As2 with 0≤x≤0.1 were prepared using a one-step solid-state reaction method. We found that overdoping of potassium can improve the critical current density (Jc). High-field Jc for samples with x=0.1 is three times higher than that for samples with x=0. Overdoping of K has minimal effect on the critical transition temperature (Tc). Less than 0.5 K degradations in Tc was measured for samples with x=0.1. Transmission electron microscopy (TEM) revealed high concentration of dislocations in samples with x=0.1, resulting in enhanced flux pining. Further analyses on magnetization loops for powder samples confirm that K overdoping can promote intragrain Jc. Our results indicate that slight excess of K in Ba0.6K0.4Fe2As2 superconductor is beneficial to high-field applications. [ABSTRACT FROM AUTHOR]

• Proposing a novel feature evaluation criterion taking feature relevance and feature interaction into consideration. • Employing Interaction Gain to examine the interaction among features. • Combining proposed feature evaluation criterion with Recursive Feature Elimination (RFE) technique to define the informative feature subset. • Experimental results on eleven public data sets showed that proposed method could measure features more accurately and stably than other methods. Defining important information from complex biological data is of great significance in biological study. It is known that the physiological and pathological changes in an organism are usually influenced by molecule interactions. Analyzing biological data by fusing the evaluation of the individual molecules and molecule interactions could induce a more accurate and comprehensive understanding of the organism. This study proposes an Interaction Gain - Recursive Feature Elimination (IG-RFE) method which evaluates the feature importance by combining the relevance between feature and class label and the interaction among features. Symmetrical uncertainty is adopted to measure the relevance between feature and the class label. The average normalized interaction gain of feature f , every other features and the class label is calculated to reflect the interaction of feature f with other features in the feature set F. Based on the combination of symmetrical uncertainty and normalized interaction gain, less important features are removed iteratively. To show the performance of IG-RFE, it was compared with seven efficient feature selection methods, MIFS, mRMR, CMIM, ReliefF, FCBF, PGVNS and SVM-RFE, on eleven public datasets. The experiment results showed the superiority of IG-RFE in accuracy, sensitivity, specificity and stability. Hence, integrating feature individual discriminative ability and the interaction among features could better evaluate feature importance in biological data analysis. [ABSTRACT FROM AUTHOR]

The title compounds are prepared from mixtures of Rh or Ir, BaS or BaSe, Ge, and S or Se (h-BN capsule, 5 GPa, 1473 K, 2 h). [ABSTRACT FROM AUTHOR]