Magnetization Plateaus in the Spin-1/2 Kagome Antiferromagnets: Volborthite and Vesignieite

The magnetization of two spin-1/2 kagome antiferromagnets, volborthite and vesignieite, has been measured in pulsed magnetic fields up to 68 T. A magnetization plateau is observed for each compound near the highest magnetic field. Magnetizations at saturation are approximately equal to 0.40Ms for both compounds, where Ms is the fully saturated magnetization, irrespective of a difference in the distortion of the kagome lattice between the two compounds. It should be noted that these values of magnetizations are significantly larger than Ms/3 predicted theoretically for the one-third magnetization plateau in the spin-1/2 kagome antiferromagnet. The excess magnetization over Ms/3 is nearly equal to the sum of the magnetizations gained at the second and third magnetization steps in volborthite, suggesting that there is a common origin for the excess magnetization and the magnetization steps.Comment: 4 pages, 4 figures. Phys. Rev. B, accepte

Perspectives of River Ecology Reseach

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Dynamics of Bound Magnon Pairs in the Quasi-One-Dimensional Frustrated Magnet LiCuVO_4

We report on the dynamics of the spin-1/2 quasi-one-dimensional frustrated magnet LiCuVO$\mathrm{_4}$ measured by nuclear spin relaxation in high magnetic fields 10--34 T, in which the ground state has spin-density-wave order. The spin fluctuations in the paramagnetic phase exhibit striking anisotropy with respect to the magnetic field. The transverse excitation spectrum probed by $^{51}$V nuclei has an excitation gap, which increases with field. On the other hand, the gapless longitudinal fluctuations sensed by $^7$Li nuclei grow with lowering temperature, but tend to be suppressed with increasing field. Such anisotropic spin dynamics and its field dependence agree with the theoretical predictions and are ascribed to the formation of bound magnon pairs, a remarkable consequence of the frustration between ferromagnetic nearest neighbor and antiferromagnetic next-nearest-neighbor interactions.Comment: 7 pages, 6 figure

多変量解析による多臓器不全患者の転帰に関する研究

Multiple Organ Failure (MOF) is a leading cause of death of the critically ill patients in the Intensive Care Unit (ICU). Even vigorous supportive care to treat completed MOF often fails. These analysis were performed to determine the risk factors for the outcome of patients with MOF. Eighty-eight consecutive adult cases that were diagnosed as MOF at the ICU of the Sapporo Medical College Hospital from 1987 to 1989 were used in this study. Multivariate statistical analysis, quantification type II was applied to the outcome of patients with MOF for 15 items. From the partial correlation coefficients of those items, factors which strongly affected the outcome were mode of nutrition, DIC score, APACHE II score, and etiology for admission to ICU. And according to the category scores in those items, feeding with total par enteral nutrition, high DIC score, high APACHE II score, and cardiothoracic surgery as a cause of ICU admission were the risk factors for the ICU death of patients with MOF. On the other hand, total or partial enteral nutrition was firmly associated with good results. These findings suggest that enteral feeding with the least possible delay should improve the outcome of MOF