NMR study on the stability of the magnetic ground state in MnCr2{}_2O4{}_4

The canting angles and fluctuation of the magnetic ion spins of spinel oxide MnCr${}_2$O${}_4$ were studied by nuclear magnetic resonance (NMR) at low temperatures, which has a collinear ferrimagnetic order below $T_C$ and a ferrimagnetic spiral order below $T_s < T_C$. Contrary to previous reports, only one spin canting angle of Cr ions was observed. The spin canting angles of Mn and Cr ions in the ferrimagnetic spiral obtained at a liquid-He temperature were 43\,^{\circ} and 110\,^{\circ}, respectively. The nuclear spin-spin relaxation was determined by the Suhl-Nakamura interaction at low temperatures but the relaxation rate $T_2^{-1}$ increases rapidly as the temperature approaches $T_s$. This indicates that the fluctuation of the spiral component becomes faster as the temperature increases but not fast enough to leave an averaged hyperfine field to nuclei in the time scale of nuclear spin precession in the ferrimagnetic phase, which is on the order of $10^{-8}$ s. The spiral volume fraction measured for various temperatures reveals that the collinear and the spiral ferrimagnetic phases are mixed below the transition temperature of the spiral order. The temperature hysteresis in the volume fraction implies that this transition has first-order characteristics.Comment: 13 pages, 5 figure

The impact of conference food function performance on attendee satisfaction and behavior

A conference event with high attendance brings in economic resources to the destination city as well as hosting company. Its food functions in particular can be an effective tool to satisfy attendees and build good attendance, as it empowers an attendee\u27s sensory memory of an event. Besides, nutritiously balanced food, which is sought-after these days, improves an attendee\u27s learning ability. The purpose of this research was to identify factors that affect the attendee\u27s perceived performance of and satisfaction with conference food function, and further, to understand an attendee\u27s return intention based on the satisfaction level. It is concluded that the quality of food content is the sole determinant of an attendee\u27s satisfaction with the food function performance and a food function predicts an attendee\u27s intention to return. Ultimately, this research provides effective implications to the industry as to ways to make a successful conference by utilizing food functions to maximize attendee satisfaction

Sliding elastic lattice: an explanation of the motion of superconducting vortices

We introduce a system where an elastic lattice of particles is moved slowly at a constant velocity under the influence of a local external potential, construct a rigid-body model through simplification processes, and show that the two systems produce similar results. Then, we apply our model to a superconducting vortex system and produce path patterns similar to the ones reported in [Lee et al., Phys. Rev. B 84, 060515 (2011)] suggesting that the reasoning of the simplification processes in this paper can be a possible explanation of the experimentally observed phenomenon.Comment: 5 pages, 3 figures, Submitted to Physical Review Letters; Reference [17] Lee et al., Phys. Rev. B Accepted changed to Lee et al., Phys. Rev. B 84, 060515 (2011

Explaining the Color Distributions of Globular Cluster Systems in Elliptical Galaxies

The colors of globular clusters in most of large elliptical galaxies are bimodal. This is generally taken as evidence for the presence of two cluster subpopulations that have different geneses. However, here we find that, because of the non-linear nature of the metallicity-to-color transformation, a coeval group of old clusters with a unimodal metallicity spread can exhibit color bimodality. The models of cluster colors indicate that the horizontal-branch stars are the main drivers behind the empirical non-linearity. We show that the scenario gives simple and cohesive explanations for all the key observations, and could simplify theories of elliptical galaxy formation.Comment: Science, 311, 1129; Minor changes to text to match the published version (9 pages, 3 figures