Effect of electronic environment on neutrino-nucleus reactions at r-process sites

We discuss effects of the electron plasma on charged-current neutrino-nucleus reaction, $(\nu_e,e^-)$ in a core-collapse supernova environment. We first discuss the electron screening effect on the final state interaction between the outgoing electron and the daughter nucleus. To this end, we solve the Dirac equation for the outgoing electron with the screened Coulomb potential obtained with the Debye-H\"{u}ckel and the Thomas-Fermi approximations. In addition to the screening effect, we also discuss the Pauli blocking effect due to the environmental electrons on the spectrum of the outgoing electron. We find that both effects hinder the cross section of the charged-current reaction, especially at low incident energies

Effect of Heteroatoms on Field-Induced Slow Magnetic Relaxation of Mononuclear Fe-III (S=5/2) Ions within Polyoxometalates.

In this paper, the synthesis and magnetic properties of mononuclear FeIII-containing polyoxometalates (POMs) with differ- ent types of heteroatoms, TBA7H10[(A-α-XW9O34)2Fe] (IIX, X = Ge, Si; TBA = tetra-n-butylammonium), are reported. In these POMs, mononuclear highly distorted six-coordinate octahedral [FeO6]9− units are sandwiched by two trivacant lacunary units [A-α- XW9O34]10− (X = Ge, Si). These POMs exhibit field-induced slow magnetic relaxation based on the single high-spin FeIII magnetic center (S = 5/2). Combining experiment and ab initio calculations, we investigated the effect of heteroatoms of the lacunary units on the field-induced slow magnetic relaxation of these POMs. By changing the heteroatoms from Si (IISi) to Ge (IIGe), the coordination geometry around the FeIII ion is mildly changed. Concretely, the axial Fe−O bond length in IIGe is shortened compared with that in IISi, and consequently the distortion of the [FeO6]9− unit in IIGe from the ideal octahedral coordination geometry becomes larger Si Ge Si than that in II . The effective demagnetization barrier of II (11.4 K) is slightly larger than that of II (9.2 K). Multireference ab initio calculations predict zero-field splitting parameters in good agreement with experiment. Although the differences in the coordination geometries and magnetic properties of IIGe and IISi are quite small, ab initio calculations indicate subtle changes in the magnetic anisotropy which are in line with the observed magnetic relaxation properties

Lidar observation of ozone over Tsukuba (36 deg N, 140 deg E)

An ozone lidar system was installed at the National Institute for Environmental Studies (NIES) in Tsukuba, Japan in March 1988 and has been measuring vertical profiles of ozone (15 - 45 km) since September 1988. The lidar system consists of a XeCl (308 nm) excimer laser, its deuterium Raman shifter (339 nm), a XeF excimer laser (351 nm), a 2 m telescope, a receiving system and a data processing system. The precision of the derived ozone concentration is about 10 percent of an altitude of 40 km for a 4 hr observation. Temperature profiles (30 - 80 km) are also obtained from the Rayleigh scattering signals at 351 nm. Approximate 50 ozone measurements are carried out in a year and variations of vertical profiles of ozone such as seasonal variations and shorter-term variations are observed. Systematic errors due to aerosols had been negligible until the arrival of the stratospheric aerosols injected by the eruption of Mt. Pinatubo. Effects of the volcanic aerosols on ozone measurements depend on the differences between wavelengths used as the on- and off-resonance

Design and fabrication of module coil as an R&D program for Large Helical Device

A twisted solenoid coil (TOKI-MC) has been designed and fabricated in order to study the mechanical properties of the Large Helical Device (LHD). One of the most important R&D items of the LHD is the mechanical behavior of the helical coils under a large electromagnetic force. The TOKI-MC was wound obliquely on the 3D-machined elliptical bobbin with a maximum torsional rate of 36deg/m at the innermost conductor. The maximum field in the coil is 7.7 T with an operating current of 20 kA, an average current density of 40 A/mm^2, and a stored energy of 11 MJ. The TOKI-MC can simulate the electromagnetic force, conductor torsional rate, magnetic field, operating current, and current density of the LHD superconducting helical coils. The design and test results of the conductor and the design and fabrication of the coil are describe

Trends in incidence and mortality of tuberculosis in Japan : a population-based study, 1997–2016

Japan is still a medium-burden tuberculosis (TB) country. We aimed to examine trends in newly notified active TB incidence and TB-related mortality in the last two decades in Japan. This is a population-based study using Japanese Vital Statistics and Japan Tuberculosis Surveillance from 1997 to 2016. We determined active TB incidence and mortality rates (per 100 000 population) by sex, age and disease categories. Joinpoint regression was applied to calculate the annual percentage change (APC) in age-adjusted mortality rates and to identify the years showing significant trend changes. Crude and age-adjusted incidence rates reduced from 33.9 to 13.9 and 37.3 to 11.3 per 100 000 population, respectively. Also, crude and age-adjusted mortality rates reduced from 2.2 to 1.5 and 2.8 to 1.0 per 100 000 population, respectively. Average APC in the incidence and mortality rates showed significant decline both in men (−6.2% and −5.4%, respectively) and women (−5.7% and −4.6%, respectively). Age-specific analysis demonstrated decreases in incidence and mortality rates for every age category, except for the incidence trend in the younger population. Although trends in active TB incidence and mortality rates in Japan have favourably decreased, the rate of decline is far from achieving TB elimination by 2035

Tunneling Desorption of Single Hydrogen on the Surface of Titanium Dioxide

We investigated the reaction mechanism of the desorption of single hydrogen from a titanium dioxide surface excited by the tip of a scanning tunneling microscope (STM). Analysis of the desorption yield, in combination with theoretical calculations, indicates the crucial role played by the applied electric field. Instead of facilitating desorption by reducing the barrier height, the applied electric field causes a reduction in the barrier width, which, when coupled with the electron excitation induced by the STM tip, leads to the tunneling desorption of the hydrogen. A significant reduction in the desorption yield was observed when deuterium was used instead of hydrogen, providing further support for the tunneling-desorption mechanism

Rapid Surface Oxidation as a Source of Surface Degradation Factor for Bi2Se3

Bi2Se3 is a topological insulator with metallic surface states residing in a large bulk bandgap. It is believed that Bi2Se3 gets additional n-type doping after exposure to atmosphere, thereby reducing the relative contribution of surface states in total conductivity. In this letter, transport measurements on Bi2Se3 nanoribbons provide additional evidence of such environmental doping process. Systematic surface composition analyses by X-ray photoelectron spectroscopy reveal fast formation and continuous growth of native oxide on Bi2Se3 under ambient conditions. In addition to n-type doping at the surface, such surface oxidation is likely the material origin of the degradation of topological surface states. Appropriate surface passivation or encapsulation may be required to probe topological surface states of Bi2Se3 by transport measurements