Gallai–Ramsey numbers for cycles

For given graphs G and H and an integer k, the Gallai–Ramsey number is defined to be the minimum integer n such that, in any k coloring of the edges of K_n, there exists a subgraph isomorphic to either a rainbow coloring of G or a monochromatic coloring of H. In this work, we consider Gallai–Ramsey numbers for the case when G=K₃ and H is a cycle of a fixed length.     

High-spin isomer in 93Mo

The high-spin states of ⁹³Mo have been studied by a ⁸²Se( ¹⁶O, 5n) ⁹³Mo reaction at a beam energy of 100 MeV using techniques of in-beam -ray spectroscopy. Measurements of -t, --t coincidences, -ray angular distributions and -ray linear polarizations were performed. The high-spin isomer was found as a (39/2^-) state at about 9.7 MeV. The near-yrast states in ⁹³Mo were interpreted using the weak-coupling picture of a d_5/2 neutron to a neutron magic core nucleus ⁹²Mo.     

Phase Manipulation between c(4 x 2) and p(2 x 2) on the Si(100) surface at 4.2 K

Phase manipulation between c(4x2) and p(2x2) on the Si(100) surface has been demonstrated at 4.2 K for the first time using a low-temperature scanning tunneling microscope. We have discovered that it is possible to change the c(4x2) surface into the p(2x2) surface, artificially, through a flip-flop motion of the buckling dimers by using a sample bias voltage control. Also, scanning at a negative bias voltage or applying a pulse voltage can restore the c(4x2) surface. The STM images as a function of bias voltage and tunneling current reveal the interesting dynamics of the buckling dimers on the long debated surface. Our results will show that energetic tunneling electrons are most likely responsible for the observed phase transition from c(4x2) to p(2x2).     

Pressure-induced superconductor-insulator transition in the spinel compound CuRh2S4

We performed resistivity measurements in CuRh2S4 under quasihydrostatic pressure of up to 8.0 GPa, and found a pressure-induced superconductor-insulator transition. Initially, with increasing pressure, the superconducting transition temperature T(c) increases from 4.7 K at ambient pressure to 6.4 K at 4.0 GPa, but decreases at higher pressures. With further compression, superconductivity in CuRh2S4 disappears abruptly at a critical pressure P(SI) between 5.0 and 5.6 GPa, when it becomes an insulator.     

Partitioned real-space density functional calculations of bielectrode systems under bias voltage and electric field

We have developed a new partitioned real-space density functional (PRDF) method and applied it to bielectrode systems under bias voltage and electric field. The electronic states, electrostatic potentials, local electric fields, and chemical potentials of biased jelliums and two Si5 clusters are fully self-consistently determined. We overcame an essential difficulty in obtaining the electronic states of biased systems from the conventional density functional method by dividing the entire system into subsystems of each electrode. The PRDF method can be applied to multielectrode systems and enables the investigation of ionic systems with computational efficiency.     

Two-pass amplification of CW laser by Nd/Cr:YAG ceramic Active mirror under lamp light pumping

The concept of an Active mirror with transparent Nd/Cr:YAG ceramics is proposed. A new ceramic material pumped by an arc-metal-halide lamp has been experimentally implemented. CW-laser light generated in a 1064 nm Nd:YAG micro-tip oscillator was amplified by an Active mirror made of Nd/Cr:YAG ceramic and pumped by CW arc-lamp light. The saturation power density of the Nd/Cr:YAG ceramic was lower than that of Nd:YAG because the stimulated-cross-section and lifetime were effectively enhanced by the sensitization of Cr ions. The maximum output laser power while keeping spatial beam quality was up to 3 W with an input lamp power of 9 W; the resulting optical-optical conversion efficiency of 33% was close to the theoretical prediction of nearly 50%.     

Laser pulses amplified by Nd/Cr:YAG ceramic amplifier using lamp and solar light sources

Laser pulses generated in a laser oscillator were amplified by Nd/Cr:YAG ceramic amplifiers. The saturation of output-laser energy was experimentally observed. We found that the stimulated emission cross-section of Nd/Cr:YAG ceramics was effectively increased and the saturation fluence was effectively reduced to 0.1 J/cm² due to the energy transfer between excited Cr and Nd ions. The output-laser energy we calculated was compared with the experimental ones and the extractable stored energy in the Nd/Cr:YAG ceramics was evaluated. This laser material is suitable for high-repetition-rate operations because of the high laser gain with low pumping intensity and low effective saturation fluence.     

Gamow-teller strengths in proton-rich exotic nuclei deduced in the combined analysis of mirror transitions

Isospin symmetry is expected for the T(z)=+/-1-->0 isobaric analogous transitions in isobars with mass number A, where T(z) is the z component of isospin T. Assuming this symmetry, strengths of analogous Gamow-Teller (GT) transitions within A = 50 isobars were determined from a high energy-resolution study at 0 degrees in combination with the decay Q value and lifetime from the beta decay. This method can be applied to other pf-shell nuclei and can be used to study GT strengths of astrophysical interest.