Development of a beamline for the study of interactions between a relativistic electron beam and crystals at the SAGA Light Source

A beamline dedicated to the study of interactions of a relativistic electron beam with crystals has been designed and constructed at the SAGA Light Source (SAGA-LS). This beamline consists of a compact two-axis goniometer in a vacuum chamber and two screen monitors placed downstream of the goniometer. An electron beam is provided from the SAGA-LS injector linac. The beam parameters such as the beam emittance and the Twiss parameters have been measured using the “Q-scan method”. Proposals for experiments on channeling radiation and parametric X-ray radiation are also discussed

Diode-type Gas Sensors Fabricated with a Titania Film on a Ti Plate and Pd-Pt Electrodes –Effects of Polymer Coating on the Hydrogen-sensing Properties–

H2 responses of a diode-type gas sensor fabricated with a TiO2 film prepared by anodization of a Ti plate and Pd-Pt electrodes (Pd-Pt/TiO2) and the effects of polymer coating on the Pd-Pt/TiO 2 sensor were investigated in this study. The H2 response of the Pd-Pt/TiO2 sensor in dry N2 was larger than that in dry air at 250°C, but the addition of moisture into the atmosphere reduced O2 concentration dependence of H2 response. The responses decreased drastically at lower temperature (50°C), but the responses in N2 were larger than those in air under both dry and wet conditions. The coating of polymer on the Pd-Pt/TiO2 sensor increased the H 2 responses in wet air and N2 and reduced O2 concentration dependence of H2 responses

Magic angle effects of the one-dimensional axis conductivity in quasi-one dimensional conductors

In quasi-one-dimensional conductors, the conductivity in both one-dimensional axis and interchain direction shows peaks when magnetic field is tilted at the magic angles in the plane perpendicular to the conducting chain. Although there are several theoretical studies to explain the magic angle effect, no satisfactory explanation, especially for the one-dimensional conductivity, has been obtained. We present a new theory of the magic angle effect in the one-dimensional conductivity by taking account of the momentum-dependence of the Fermi velocity, which should be large in the systems close to a spin density wave instability. The magic angle effect is explained in the semiclassical equations of motion, but neither the large corrugation of the Fermi surface due to long-range hoppings nor hot spots, where the relaxation time is small, on the Fermi surface are required.Comment: 4 pages, 3 figure

Root hydrotropism is controlled via a cortex-specific growth mechanism

Plants can acclimate by using tropisms to link the direction of growth to environmental conditions. Hydrotropism allows roots to forage for water, a process known to depend on abscisic acid (ABA) but whose molecular and cellular basis remains unclear. Here, we show that hydrotropism still occurs in roots after laser ablation removed the meristem and root cap. Additionally, targeted expression studies reveal that hydrotropism depends on the ABA signalling kinase, SnRK2.2, and the hydrotropism-specific MIZ1, both acting specifically in elongation zone cortical cells. Conversely, hydrotropism, but not gravitropism, is inhibited by preventing differential cell-length increases in the cortex, but not in other cell types. We conclude that root tropic responses to gravity and water are driven by distinct tissue-based mechanisms. In addition, unlike its role in root gravitropism, the elongation zone performs a dual function during a hydrotropic response, both sensing a water potential gradient and subsequently undergoing differential growth

Simultaneous charge polarization and fragmentation of N₂ molecules in slow keV collisions with Kr⁸⁺ ions

Coulomb fragmentation processes in collisions of Kr8+ ions with nitrogen molecules were studied at projectile energies between 19 and 171 eV/u. At low impact energies (less than or similar to50 eV/u) and small impact parameters, the electron distribution of the fragmenting molecular N-2(q+) ion becomes strongly polarized. This is due to the presence of the slow highly charged projectile during the fragmentation process. Microscopic calculations simultaneously incorporating electron transfer and molecular dissociation give insight into the dynamics of this newly found polarization effect