New Matsushiro underground cosmic ray station (220 M.W.E. in depth)

A new underground cosmic ray station has been opened at Matsushiro, Japan, and a multidirectional (17 directional channels) muon telescope has been installed at an effective vertical depth of 220 m.w.e. The counting rates are; 8.7 x 10,000/hr for the wide vertical component and 2.0 x 10,000/hr for the vertical component. Continuous observation has been performed since March 22,1984. Some details of the telescope and preliminary analyzed results of the data are presented

Emergence of metallic surface states and negative differential conductance in thin β\beta-FeSi2_2 films on Si(001)

The electronic properties of the surface of $\beta$-FeSi$_2$ have been debated for a long while. We studied the surface states of $\beta$-FeSi$_2$ films grown on Si(001) substrates using scanning tunnelling microscopy (STM) and spectroscopy (STS), with the aid of density functional theory (DFT) calculations. STM simulations using the surface model proposed by Romanyuk et al. [Phys. Rev. B 90, 155305 (2014)] reproduce the detailed features of experimental STM images. The result of STS showed metallic surface states in accordance with theoretical predictions. The Fermi level was pinned by a surface state that appeared in the bulk band gap of the $\beta$-FeSi$_2$ film, irrespective of the polarity of the substrate. We also observed negative differential conductance at $\sim$0.45 eV above the Fermi level in STS measurements performed at 4.5 K, reflecting the presence of an energy gap in the unoccupied surface states of $\beta$-FeSi$_2$.Comment: 16 pages, 5 figure

Regional differences in the incidence of severe brain damage in survivors with cardiac disease and witnessed out-of-hospital cardiac arrest

Background: Brain damage can occur after out-of-hospital cardiac arrest (OHCA) leading to permanent disability.Aims: This study investigated the incidence of severe brain damage and associated risk factors in survivors with cardiac disease after OHCA.Methods: The Utstein database for Japan was used to identify 23,640 survivors with cardiac disease and witnessed OHCA between 2005 and 2012. Survivors were assessed at 1 month. Odds ratios (ORs) for the incidence of severe brain damage according to regional variables were determined with logistic regression analysis.Results: The incidence of severe brain damage was 37.3%. Automated external defibrillator use and cardiopulmonary resuscitation were associated with significant improvement in cerebral function; adrenaline administration and longer duration from request for transport until hospital arrival were associated with deterioration of cerebral function. Twenty of 47 prefectures showed significant ORs for the incidence of severe brain damage.Conclusion: Regional differences in the incidence of severe brain damage were found among survivors with cardiac disease and witnessed OHCA

CONTINUOUS MEASUREMENTS OF COSMIC-RAY INTENSITY WITH MULTI-DIRECTIONAL MUON TELESCOPE 50 M.W.E. UNDERGROUND AT MATSUMOTO

A multi-directional muon telescope having an area of 8m² was constructed in a tunnel with a vertical depth of approximately 50 m. w. e. at Matsumoto. Continuous measurements of cosmic-ray intensity have been made since April 7, 1971. A preliminary report is presented concerning the underground site, experimental apparatus, and its arrangement, as well as some examples of experimental data obtained, and analyzed results of cosmic-ray daily variation. Counting-rates are 6 x 10⁴/hr of vertical component for 8 m² area at a depth of ～50 m. w. e., and 3.4 x 10⁴ /hr of N-component at ～42 m. w. e., 0.85 x 10⁴ /hr of S-component at ～92 m. w. e. for each of 6 m² area, 1. 1 x 10⁴ /hr of E-component at ～65 m. w. e., and 1. 55 x 10⁴ /hr of W-component at ～53 m.w.e. for each of 4m² area, inclined at 40° to the vertical. It is found that the observed phases of diurnal and semidiurnal vectors for five components are indicative of the extraterrestrial nature of the daily variation. The observation thus may provide an important information on the modulation of cosmic-ray intensity variation.Article信州大学教養部紀要. 第二部, 自然科学 6: 9-30(1972)departmental bulletin pape

Topological surface states hybridized with bulk states of Bi-doped PbSb2Te4 revealed in quasiparticle interference

Topological surface states of Bi-doped PbSb2Te4 [Pb(Bi0.20Sb0.80)2Te4] are investigated through analyses of quasiparticle interference (QPI) patterns observed by scanning tunneling microscopy. Interpretation of the experimental QPI patterns in the reciprocal space is achieved by numerical QPI simulations using two types of surface density of states produced by density functional theory calculations or a kp surface state model. We found that the Dirac point (DP) of the surface state appears in the bulk band gap of this material and, with the energy being away from the DP, the isoenergy contour of the surface state is substantially deformed or separated into segments due to hybridization with bulk electronic states. These findings provide a more accurate picture of topological surface states, especially at energies away from the DP, providing valuable insight into the electronic properties of topological insulators.Comment: 7+8 pages, 4+5 figure

Spreading of aqueous surfactant solutions on oil substrates: Superspreaders vs non-superspreaders

HypothesisThe question of why aqueous solutions of some surfactants demonstrate a rapid spreading (superspreading) over hydrophobic solid substrates, while solutions of other similar surfactants do not, has no definitive explanation despite numerous previous studies. The suggested hypothesis for this study assumes that once the spreading coefficient of surfactant is positive, there is a concentration range for solutions of any surfactant which demonstrates rapid spreading. As it is impossible to calculate spreading coefficients for solid substrates, we compare the spreading performance of known superspreaders and non-superspreaders on liquid (oil) substrate.ExperimentsThe kinetics of spreading of aqueous solutions of a series of branched ionic surfactants and non-ionic trisiloxane surfactants on two liquid substrates was studied and compared with the spreading of a surfactant-free liquid, silicone oil. Both dynamic and equilibrium spreading coefficients were calculated using measured surface and interfacial tensions.FindingsThere is no difference in spreading rate on liquid substrate between solutions of surfactants proven as superspreaders (while spreading on solid substrate) or non-superspreaders. A rapid spreading (superspreading) with the characteristic rate of spreading O(102–103) mm2/s occurs if the dynamic spreading coefficients exceeds the positive threshold value. If the dynamic spreading coefficient is negative or slightly positive, complete wetting still occurs, but the spreading is slow with the spreading rate is O(1) mm2/s. Spreading exponents for surfactant solutions in the rapid spreading regime are considerably larger than for the surfactant-free liquid. A number of spreading and dewetting patterns were observed depending on the surfactant type, its concentration and substrate