Cyclotron Resonance in the Hidden-Order Phase of URu_{2}Si_{2}

We report the first observation of cyclotron resonance in the hidden-order phase of ultraclean URu_{2}Si_{2} crystals, which allows the full determination of angle-dependent electron-mass structure of the main Fermi-surface sheets. We find an anomalous splitting of the sharpest resonance line under in-plane magnetic-field rotation. This is most naturally explained by the domain formation, which breaks the fourfold rotational symmetry of the underlying tetragonal lattice. The results reveal the emergence of an in-plane mass anisotropy with hot spots along the [110] direction, which can account for the anisotropic in-plane magnetic susceptibility reported recently. This is consistent with the "nematic" Fermi liquid state, in which itinerant electrons have unidirectional correlations.     

Atomic structure of two-dimensional binary surface alloys: Si(111)-√21 × √21 superstructure

The atomic structures of Au and Ag co-adsorption-induced √21 × √21 superstructure on a Si(111) surface, i.e., (Si(111)-√21 × √21-(Au, Ag)), where the Si(111)-5 × 2-Au surface is used as a substrate, have been investigated using reflection high-energy positron diffraction (RHEPD) and photoemission spectroscopy. From core-level spectra, we determined the chemical environments of Ag and Au atoms present in the Si(111)-√21 × √21-(Au, Ag) surface. From the rocking curve and pattern analyses of RHEPD, we found that the atomic coordinates of the Au and Ag atoms were approximately the same as those of the Au and Ag atoms in other Si(111)-√21 × √21 surfaces with different stoichiometries. On the basis of the core-level and RHEPD results, we revealed the atomic structure of the Si(111)-√21 × √21-(Au, Ag) surface.     

Universal reconnection of non-Abelian cosmic strings

We show that local and semilocal strings in Abelian and non-Abelian gauge theories with critical couplings always reconnect classically in collision, by using moduli space approximation. The moduli matrix formalism explicitly identifies a well-defined set of the vortex moduli parameters. Our analysis of generic geodesic motion in terms of those shows right-angle scattering in head-on collision of two vortices, which is known to give the reconnection of the strings.     

A predissociative triplet Rydberg state of the nitrogen molecule studied by near-infrared diode laser kinetic spectroscopy

A new ³Π-³Σ band was observed in a discharge plasma of the nitrogen molecule and helium using near-infrared diode laser kinetic spectroscopy. All the lines in this band exhibited line broadening of more than 0.1 cm⁻¹. Rotational analysis revealed that the lower state of the transition was the state of N₂, which had already been studied in the D³Σ-E³Σ band. The term value and rotational constant suggested that the upper state is the G³Π_u Rydberg state with an electron configuration of (N₂⁺:X²Σ core)(3pπ_u). The line broadening is attributed to predissociation through a homogeneous interaction with a repulsive Π_u state.     

Applications of Infrared Spectroscopy to Biochemical,Food, and Agricultural Processes

Abstract

Integrated investigations on infrared spectroscopic characteristics of metabolites and on applications of infrared spectroscopy to foodstuff production, food processing, and tasting are described. As the important metabolites, saccharides, which play very important roles in various functions, located in the central position of the metabolic pathways, were selected, and the spectral features of the saccharides and related materials are discussed. Additionally, the applications of spectral analysis to the monitoring of the enzyme reaction and the sugar metabolic processes, which are the main materials in food processing, are described. Furthermore, the studies on the spectroscopic measurements during the cultivation of agricultural products as foodstuffs and in the tasting as the final quality evaluation of foods are represented. These results suggest that infrared spectroscopy could be very effective for evaluating foodstuff production and the tasting of the processed foods and that the applied topics should provide fundamental information about the spectral behavior of the metabolites and bioproducts.     

On/off spin-crossover phenomenon and control of the transition temperature in assembled Iron(II) complexes

The present study reveals the on/off of spin-crossover (SCO) phenomenon in assembled Fe(II) complexes bridged by bis(pyridyl) type ligand. Whether SCO phenomenon occurs or not in assembled Fe(II) complexes bridged by bis(pyridyl) type ligand is determined by local structure around iron atom. SCO phenomenon occurs when the coordinating pyridines facing to each other across the iron atom are propeller type, while the phenomenon does not occur when they are parallel type or distorted propeller type. DFT calculation explained that, in the shortening of Fe-pyridine bonds when changing from high-spin state to low-spin state, the pyridines of propeller type can approach the iron atom with smaller steric hindrance than those of parallel and distorted propeller type complexes. The local structure is controlled by introducing methyl substituent and introducing π-system, changing SCO phenomenon. And the transition temperature of SCO is also controlled in assembled complexes bridged by 1,2-bis(4-pyridyl)ethane by mixing anionic ligand.     

Soot formation characteristics in a lab-scale turbulent pulverized coal flame with simultaneous planar measurements of laser induced incandescence of soot and Mie scattering of pulverized coal

Soot formation characteristics of a lab-scale pulverized coal flame were investigated by performing carefully controlled laser diagnostics. The spatial distributions of soot volume fraction and the pulverized coal particles were measured simultaneously by laser induced incandescence (LII) and Mie scattering imaging, respectively. In addition, the radial distributions of the soot volume fraction were compared with the OH radical fluorescence, gas temperature and oxygen concentration obtained in our previous studies [1], [2]. The results indicated that the laser pulse fluence used for LII measurement should be carefully controlled to measure the soot volume fraction in pulverized coal flames. To precisely measure the soot volume fraction in pulverized coal flames using LII, it is necessary to adjust the laser pulse fluence so that it is sufficiently high to heat up all the soot particles to the sublimation temperature but also sufficiently low to avoid including a too large of a change in the morphology of the soot particles and the superposition of the LII signal from the pulverized coal particles on that from the soot particles. It was also found that the radial position of the peak LII signal intensity was located between the positions of the peak Mie scattering signal intensity and peak OH radical signal intensity. The region, in which LII signal, OH radical fluorescence and Mie scattering coexisted, expanded with increasing height above the burner port. It was also found that the soot formation in pulverized coal flames was enhanced at locations where the conditions of high temperature, low oxygen concentration and the existence of pulverized coal particles were satisfied simultaneously.     

Study of γ d → π + π − d Reaction in an Energy Region of 0.67 ≤ E γ ≤ 1.08 GeV

Double charged pion photoproductions from the deuteron have been studied at Research Center for Electron Photon Science (ELPH), Tohoku University. Tagged photon beams in an energy range of 0.67 ≤ E _γ ≤ 1.08 GeV were impinged on the liquid deuteron target. Produced charged particles were observed with the Neutral Kaon Spectrometer2 (NKS2). The γ d → π ⁺ π ^? d process was clearly separated among the three charged tracks. We obtained the photon energy dependence of the normalized yields of this process.