On class numbers of quadratic extensions¶over function fields

We consider class numbers of quadratic extensions over a fixed function field. We will show that there exist infinitely many quadratic extensions which have class numbers not being divisible by 3 and satisfy prescribed ramification conditions. Received: 24 October 1997 / Revised version: 26 February 1998     

Structure comparison between Th2Zn17-type and TbCu7-type Sm–Fe intermetallic compounds and their nitrides by means of 57Fe-Mössbauer spectroscopy

Samarium–iron intermetallic compounds were prepared by a melt spinning method with low and high wheel speeds, which resulted in a Th₂Zn₁₇-type and a TbCu₇-type structure, respectively. Structure comparison between these types was investigated for Sm–Fe intermetallic compounds and their nitrides by ⁵⁷Fe-Mössbauer spectroscopy.     

Regression-based model of skin diffuse reflectance for skin color analysis

A simple regression-based model of skin diffuse reflectance is developed based on reflectance samples calculated by Monte Carlo simulation of light transport in a two-layered skin model. This reflectance model includes the values of spectral reflectance in the visible spectra for Japanese women. The modified Lambert Beer law holds in the proposed model with a modified mean free path length in non-linear density space. The averaged RMS and maximum errors of the proposed model were 1.1 and 3.1%, respectively, in the above range.     

Annealing behavior of a void network in amorphous silicon

A void network in a-Si films prepared by vacuum deposition was studied. A close relationship in annealing behavior has been observed between the changes in surface area of voids and in the ESR signal strength.     

Observables and quark confinement in the covariant canonical formalism of Yang-Mills theory

A concise criterion for observables in Yang-Mills theory is presented in the framework of covariant canonical field theory. As an example, the symmetric energy-momentum tensor θ_øν is proved to be an observable and its physically meaningful form is clarified. The validity of the “Maxwell-type” equation of motion is established in the physical subspace $\text{V}$_phys defined by the subsidiary condition $\text{Q}{}_{\mathrm{<mtext>B</mtext>}}\text{?}\text{phys}\text{〉 = 0}$ (Q_B: BRS charge). Its meaning and consequences are discussed in connection with the notion of observables: especially, all (quasi-) local observables in QCD are shown to be colour singlets and this fact paves the way to quark confinement.     

The synthesis of 2-ethoxy-6,11-dimethyl-7,9-bisdehydroaza[14]annulene and its benzannelated derivatives

Title azaannulenes were synthesized starting from annulenones, and the ¹H-NMR spectra are discussed in connection with tropicity of these annulenes.     

Magnetic field dip and the lifetime of the spherical tensor element of the density matrix in a He-Ne laser

The magnetic field dips (MFD) of the 0.633 and 1.15 μm lines of a He-Ne laser are investigated. It is found that the widths of the MFD signals are not determined by a single upper or lower laser state. Thus, there is some ambiguity in the interpretation of the MFD measurement for the determination of the lifetime, which is difficult to resolve theoretically or experimentally. The effect of pressure on MFD is also discussed, with emphasis on excitation-transfer collisions between the excited and ground states of neon atoms.