Thermally activated flux flow in superconducting epitaxial FeSe0.6Te0.4 thin film

AbstractThe thermally activated flux flow effect has been studied in epitaxial FeSe0.6Te0.4 thin film grown by a PLD method through the electrical resistivity measurement under various magnetic fields for B//c and B//ab. The results showed that the thermally activated flux flow effect is well described by the nonlinear temperature-dependent activation energy. The evaluated apparent activation energy U0(B) is one order larger than the reported results and showed the double-linearity in both magnetic field directions. Furthermore, the FeSe0.6Te0.4 thin film shows the anisotropy of 5.6 near Tc and 2D-like superconducting behavior in thermally activated flux flow region. In addition, the vortex glass transition and the temperature dependence of the high critical fields were determined

Difference in anisotropic vortex pinning in pristine and proton-irradiated (Ca0.85La0.15)10(Pt3As8)(Fe2As2)5 single crystals

We measured the in-plane electrical resistivity of pristine and irradiated (Ca0.85La0.15)10(Pt3As8)(Fe2As2)5 single crystals in B//c and B//ab up to B = 13 T to study the difference between in-plane and out-of-plane vortex pinning and the effect of proton irradiation on these pinning. The crystal structure analyzed by the selected area electron diffraction was monoclinic in these two samples. Protons incident along the c-axis caused an expansion of the lattice constants a and b. The expansion of the lattice constants significantly increased the c-axis coherence length ξc. The vortex pinning in B//ab is well understood by an intrinsic pinning mechanism, which was attenuated by proton irradiation. On the other hand, the vortex pinning in B//c is well understood by the plastic creep theory due to point defects that are enhanced by proton irradiation. © 2021 The Author(s)1

Construction status and prospects of the Hyper-Kamiokande project

The Hyper-Kamiokande project is a 258-kton Water Cherenkov together with a 1.3-MW high-intensity neutrino beam from the Japan Proton Accelerator Research Complex (J-PARC). The inner detector with 186-kton fiducial volume is viewed by 20-inch photomultiplier tubes (PMTs) and multi-PMT modules, and thereby provides state-of-the-art of Cherenkov ring reconstruction with thresholds in the range of few MeVs. The project is expected to lead to precision neutrino oscillation studies, especially neutrino CP violation, nucleon decay searches, and low energy neutrino astronomy. In 2020, the project was officially approved and construction of the far detector was started at Kamioka. In 2021, the excavation of the access tunnel and initial mass production of the newly developed 20-inch PMTs was also started. In this paper, we present a basic overview of the project and the latest updates on the construction status of the project, which is expected to commence operation in 2027

Prospects for neutrino astrophysics with Hyper-Kamiokande

Hyper-Kamiokande is a multi-purpose next generation neutrino experiment. The detector is a two-layered cylindrical shape ultra-pure water tank, with its height of 64 m and diameter of 71 m. The inner detector will be surrounded by tens of thousands of twenty-inch photosensors and multi-PMT modules to detect water Cherenkov radiation due to the charged particles and provide our fiducial volume of 188 kt. This detection technique is established by Kamiokande and Super-Kamiokande. As the successor of these experiments, Hyper-K will be located deep underground, 600 m below Mt. Tochibora at Kamioka in Japan to reduce cosmic-ray backgrounds. Besides our physics program with accelerator neutrino, atmospheric neutrino and proton decay, neutrino astrophysics is an important research topic for Hyper-K. With its fruitful physics research programs, Hyper-K will play a critical role in the next neutrino physics frontier. It will also provide important information via astrophysical neutrino measurements, i.e., solar neutrino, supernova burst neutrinos and supernova relic neutrino. Here, we will discuss the physics potential of Hyper-K neutrino astrophysics

Discovery of widespread transcription initiation at microsatellites predictable by sequence-based deep neural network

Using the Cap Analysis of Gene Expression (CAGE) technology, the FANTOM5 consortium provided one of the most comprehensive maps of transcription start sites (TSSs) in several species. Strikingly, ~72% of them could not be assigned to a specific gene and initiate at unconventional regions, outside promoters or enhancers. Here, we probe these unassigned TSSs and show that, in all species studied, a significant fraction of CAGE peaks initiate at microsatellites, also called short tandem repeats (STRs). To confirm this transcription, we develop Cap Trap RNA-seq, a technology which combines cap trapping and long read MinION sequencing. We train sequence-based deep learning models able to predict CAGE signal at STRs with high accuracy. These models unveil the importance of STR surrounding sequences not only to distinguish STR classes, but also to predict the level of transcription initiation. Importantly, genetic variants linked to human diseases are preferentially found at STRs with high transcription initiation level, supporting the biological and clinical relevance of transcription initiation at STRs. Together, our results extend the repertoire of non-coding transcription associated with DNA tandem repeats and complexify STR polymorphism

Purification of molybdenum trioxide calcine by selective leaching of copper with HCl–NH4Cl

The leaching of Mo, Cu and Fe from MoO(3) calcines (59-61% Mo) containing 1-2% Cu, 1-2% Fe and other impurities produced from roasting molybdenite (MoS(2)) concentrate was examined using water and a series of chloride lixiviants, including NH(4)Cl (0.6 M), HCl (0.115-1.40 M) and a mixture of HCl (0.70 M) + NH(4)Cl (0.1-0.93 M) at a solid/leachant (w/v) ratio of 1:1 and within the temperature range 25-70 degrees C. Stabcal modelling showed that there are many compounds formed from Cu, Fe and Mo co-exist in the solution. Optimisation studies show that HCl solutions of concentrations >= 0.35 M are capable of dissolving >80% of Cu within 1 h. The addition of NH(4)Cl (0.30-0.93 M) to 0.7 MHCl reduces the dissolution of Mo to <0.5%, due to the formation of a precipitate containing mainly NH(3)(MoO(3))(3), as confirmed by X-ray diffraction. A mixture of 0.7 M HCl and 0.6 M NH(4)Cl at ambient temperatures removes Cu to <0.5% within 2 h, as required for the production of Fe-Mo alloys at Kwangyang Ferro Alloys Co. (Korea). Although not required, Fe was removed to <0.6% whereas most other metal impurities were removed to <0.1%. Pilot plant trials over 7 campaigns, each treating 2.0-2.2 tonnes of MoO(3) calcine containing 2.1% Cu using 1.44 M NH(4)Cl and 0.97 M HCl at an ambient temperature yielded final products containing 0.22% Cu as required. Mass balance calculations (closure to 96-99%) of the pilot plant trials confirm that the Mo loss during leaching is around 0.5%

Optical properties in the hole-doped Ca8.5Na1.5(Pt3As8)(Fe2As2)5 single crystal

For newly synthesized hole-doped Ca8.5Na1.5(Pt3As8)(Fe2As2)5 single crystals, we measured the infrared reflectivity spectrum and the magnetic field dependence of magnetoresistivity and Hall resistivity. The results of these two experiments in normal states are well described by two band models. In normal states below 150 K, the optical conductivity spectrum shows the transfer of spectral weights from the mid-infrared region to the near-infrared region by Hund's coupling, a strong correlation effect. Meanwhile, the carrier concentration evaluated by magnetoresistivity and Hall resistivity decreases significantly at 150 K due to the formation of pseudogap. In the superconducting state, the spectral weight in the low frequency region by the superconducting condensate is completely suppressed, which is well analyzed by the generalized Mattis-Bardeen (M-B) model with a two superconducting gap

Corrigendum to’ Purification of molybdenum trioxide calcine by selective leaching of copper with HCl–NH4Cl.’ [Hydrometallurgy 109 (2011) 9–17. / 1-s2.0-S0304386X11001137]

The authors regret to inform that there was a correction in the author's name Sang Yun Seo to Sangyun Seo. The authors would like to apologise for any inconvenience caused..