Internal reflectance spectroscopy associated with cyclic staircase voltammetry using a microcomputer

In order to obtain extensive information on electrode-solution interfaces, a rapid-scan internal reflectance spectroscopic system is combined with cyclic staircase voltammetry; the staircase wave generated by computer software is applied to an optically transparent tin oxide electrode. The internal reflectance spectrum is measured at each step of the applied staircase voltage simultaneously with the instantaneous current.     

ESR study on the structure of the ethylene radical cation stabilized in frozen SF6 and some fluoroalkanes: An evidence for a twisted structure

ESR spectra of the ethylene radical cation were detected at cryogenic temperatures in SF₆, C₂F₆ and C₃F₈. From the unusually small hyperfine couplings estimated for¹H and¹³C, it has been shown that the ethylene radical cation has a non-planar structure with a torsional angle in the range of 8°–23°. Upon annealing the sample at a temperature above 93 K, the ethylene radical cation in SF₆ changed into a monofluoroethyl radical through charge recombination with fluoride anion or SF ₆ ^? .     

Identification of a dehydrodimer of avenanthramide phytoalexin in oats

A new compound (1) was found to accumulate when oat leaves were treated with elicitors. A reaction with peroxidase and avenanthramide B, an oat phytoalexin, in the presence of hydrogen peroxide resulted in the formation of 1. The chemical structure of 1 was determined to be a cyclic dehydrodimer of avenanthramide B based on spectroscopic analyses and chemical derivatization, and 1 was named bisavenanthramide B.     

Synthesis and Properties of an Overcrowded Silabenzene Stable at Ambient Temperature

Solid-state, room-temperature stability for silabenzene 1 is granted by the bulky silane rendering kinetic inertness. Silabenzene 1 is synthesized in good yield from the crowded chlorosilane 2 with tert-butyllithium. The delocalized, aromatic nature of 1 was confirmed by NMR spectroscopy and the (1)J(Si-C) value, as well as calculations on an analogous silabenzene.     

Toric Rings Arising from Cyclic Polytopes

Let d and n be positive integers with n ≥ d + 1 and 𝒫 ? ? ^d an integral cyclic polytope of dimension d with n vertices, and let K[𝒫] = K[?_≥0𝒜_𝒫] denote its associated semigroup K-algebra, where 𝒜_𝒫 = {(1, α) ∈ ? ^d+1: α ∈ 𝒫} ∩ ? ^d+1 and K is a field. In the present paper, we consider the problem when K[𝒫] is Cohen–Macaulay by discussing Serre's condition (R ₁), and we give a complete characterization when K[𝒫] is Gorenstein. Moreover, we study the normality of the other semigroup K-algebra K[Q] arising from an integral cyclic polytope, where Q is a semigroup generated by its vertices only.     

Direct observations of vortices in a high-Tc superconductor (La1-xSrx)2CuO4 by scanning SQUID microscopy

In order to investigate the behavior of vortices in high-T_c superconductors under low magnetic fields, we have performed scanning SQUID microscopy (SSM) on the ab-surfaces of (La_1-xSr_x)₂CuO₄ (LSCO) single crystals at low temperatures. The observed magnetic images clearly demonstrated vortices in units of K₀ (=hc/2e) below T_c. Vortices trapped inside the overdoped LSCO tended to be arranged in a one-dimensional manner, while those in optimally doped crystals were randomly distributed. From the variable-temperature SSM measurements, it was directly visualized that the normal state with regular magnetic-field distribution gradually changed into the inhomogeneous Meissner state, and finally vortices evolved, with decreasing temperature.     

Influence of relaxation phenomena in dynamic magnetization processes on magnetic power losses of non-oriented electrical steel sheets

We have reported that the magnetic power losses per magnetizing cycle change with the magnetization pausing time in a constant rate of magnetization change and some relaxation phenomena exist in the magnetization pausing period. We discuss the influence of the relaxation phenomena on the dynamic magnetic power losses and suggest that the relaxation phenomena seems to be causes of the frequency dependence of the magnetic losses and of the variation of losses that cannot be expressed only by magnetization speed dependence of losses.