Ferrimagnetic order in the mixed garnet (Y1− x Gd x )3Fe5O12

Ferrimagnetic order in the mixed rare-earth iron garnet (Y₁?_?? _x Gd _x )₃Fe₅O₁₂ system has been reinvestigated to cover the temperature range 5.0 to 700?K. The magnetization versus temperature exhibits a systematic variation with changing concentration x. The ferric-ion exchange coupling is strong enough to determine the Curie temperature ≈559?K for all the values x. The compensation temperature at which the magnetization crosses zero (shows the minimum) demonstrates the applicability of the three-sublattice model. The magnetic moment at 5.0?K indicates reasonable agreement with the relation n _B?=?|21x???5.0|μ_B for the (Y₁?_?? _x Gd _x )₃Fe₅O₁₂ system. The compensation temperature decreases with decreasing x from 1.0 and reaches zero near x?=?0.24. An enlargement of coercive force in the hysteresis loop for the low-field M-H curve is clearly seen in near the compensation temperature, indicating that a single domain is formed and the rotation of this single domain occurs without building up a multidomain structure.     

Dynamic instability of a wheel moving on a discretely supported infinite rail

The parametric instability of a wheel moving on a discretely supported rail is discussed. To achieve this, an analysis method is developed for a quasi-steady-state problem which can represent an exponential growth of oscillation. The temporal Fourier transform of the rail motion is expanded by a Fourier series with respect to the longitudinal coordinate, and then the response of the rail deflection due to a quasi-harmonic moving load is derived. The wheel/track interaction is formulated by the aid of this function and reduced to an infinite system of linear equations for the Fourier coefficients of the contact force. The critical velocities between the stable and unstable states are calculated based on the nontrivial condition of the homogeneous matrix equation. Through these analyses the influences of the modeling of rail and rail support on the unstable speed range are examined. Moreover, not only the first instability zone but also other zones are evaluated.     

A Remark on the Courant-Friedrichs-Lewy Condition in Finite Difference Approach to PDE's

The Courant-Friedrichs-Lewy condition (The CFL condition) is appeared in the analysis of the finite difference method applied to linear hyperbolic partial differential equations. We give a remark on the CFL condition from a view point of stability, and we give some numerical experiments which show instability of numerical solutions even under the CFL condition. We give a mathematical model for rounding errors in order to explain the instability.     

Mechanism of asymmetric sulfimidation with N-alkoxycarbonyl azide in the presence of (OC)Ru(salen) complex

Spectroscopic analysis of imidation of alkyl aryl sulfides with N-2,2,2-trichloro-1,1-dimethylethyloxycarbonyl azide 2 in the presence of (OC)Ru(salen) complex 1 strongly suggests that an addition compound of the azide 2 to 1 is the active species for the imidation, while the addition compound undergoes the undesired intramolecular CH insertion onto the salen ligand of the complex in the absence of sulfide, directly or via the corresponding nitrene-ruthenium species.     

Chromatographic characterization of hydrophilic interaction liquid chromatography stationary phases: hydrophilicity, charge effects, structural selectivity, and separation efficiency

Fourteen commercially available particle-packed columns and a monolithic column for hydrophilic interaction liquid chromatography (HILIC) were characterized in terms of the degree of hydrophilicity, the selectivity for hydrophilic-hydrophobic substituents, the selectivity for the regio and configurational differences in hydrophilic substituents, the selectivity for molecular shapes, the evaluation of electrostatic interactions, and the evaluation of the acidic-basic nature of the stationary phases using nucleoside derivatives, phenyl glucoside derivatives, xanthine derivatives, sodium p-toluenesulfonate, and trimethylphenylammonium chloride as a set of samples. Principal component analysis based on the data of retention factors could separate three clusters of the HILIC phases. The column efficiency and the peak asymmetry factors were also discussed. These data on the selectivity for partial structural differences were summarized as radar-shaped diagrams. This method of column characterization is helpful to classify HILIC stationary phases on the basis of their chromatographic properties, and to choose better columns for targets to be separated. Judging from the retention factor for uridine, these HILIC columns could be separated into two groups: strongly retentive and weakly retentive stationary phases. Among the strongly retentive stationary phases, zwitterionic and amide functionalities were found to be the most selective on the basis of partial structural differences. The hydroxyethyl-type stationary phase showed the highest retention factor, but with low separation efficiency. Weakly retentive stationary phases generally showed lower selectivity for partial structural differences.     

An extension of Krugman’s core–periphery model to the case of a continuous domain: Existence and uniqueness of solutions of a system of nonlinear integral equations in spatial economics

We consider a model that is an extension of Krugman’s core–periphery model to the case of a bounded closed domain included in a Euclidean space. We can describe the relation of the density of workers, the density of nominal wages, and the density of real wages by the system of nonlinear integral equations of the model. If we obtain a solution of the system under the condition that the density of workers is given, then the solution is called a short-run equilibrium. In this paper we prove that this model has a short-run equilibrium, and we obtain a sufficient condition for its uniqueness. Moreover we obtain upper and lower estimates for short-run equilibria, and we construct a useful iteration scheme to numerically obtain short-run equilibria.     

A comparative visualization tool for ocean data analysis based on mode water regions

Journal of Visualization - Ocean data have been improved with the enhancement of observed values and the evolution of computational technologies. It has also been verified based on the...     

Studies on a new biosynthetic pathway for menaquinone

Menaquinone is biosynthesized from chorismate via a new pathway involving 1,4-dihydroxy-6-naphthoate in Streptomyces and presumably in pathogenic bacteria Helicobacter and Campylobacter.     

Data fitting independent of grid structure using a volumic version of MPU

Abstract  

Volume graphics is a key technology in fields such as fluid dynamics and medical science. The visualization of volume data requires the creation of a continuous scalar field to exactly or approximately interpolate scalar values assigned to the discrete voxels. In the present paper, we propose a method that we refer to as the volumic version of the multi-level partition of unity (volumic MPU). The method approximately interpolates the scalar values with good precision to generate a scalar field that is continuous up to second-order differentiation. The volumic MPU, being independent of grid structures of input volume data, is applicable to both irregular-grid data and regular grid data. The volumic MPU can also be used as an effective data-compression technique. The speed to evaluate the created scalar field is almost as high as that of trilinear interpolation.