A study of the multiple pinhole coded aperture and the application of the minicomputer in image decoding.

Research has been done on optically reconstructed imaging employing the Multiple Pinhole Coded Aperture (hereafter abreviated as MPCA) in radioisotope tomographic imaging. However, problems remain in the optically reconstructed image method. Therefore, we employed a minicomputer (hereafter abbreviated as CPU) and developed the software for decoding and managing the radioisotope tomographic image. Combining the MPCA and the CPU system, we were able to decode and manage the radioisotope tomographic image. 1) In comparison to the optically decoded MPCA image, various input commands are possibly in the CPU method according to the dialogue between the CPU and the on line typewriter. In addition to this, decoded tomographic images of unrestricted depth are readily attainable. 2) In the CPU method noise elimination and other aspects of image management can be easily performed.     

Mössbauer and its r.f. sideband effects in iron-rich glassy alloys

Room temperature Mössbauer and its r.f. induced sideband effects are studied in glassy Fe₄₀Ni₄₀P₁₄B₆ and Fe₈₀P₁₆C₃B₁ alloys in ribbon forms. The direction of the magnetic anisotropy is found to be in the plane of the ribbon for the first alloy while the latter has some out-of-plane anisotropy component. The 3d electronic configuration for iron in the two alloys seems to be about the same in light of the observed isomer shifts and the electron donor model. The r.f. induced sidebands in the spectra are attributed to the magnetostriction of the present alloys.     

Mean-field theory for quenched reduced large-N gauge model

The reduced model à la Eguchi and Kawai, its quenched version and the Wilson theory in the string variable representation are studied by employing the loop expansion around the mean field. The spontaneous breakdown of the U(1)^d symmetry in the Eguchi-Kawai model is thoroughly investigated. It is shown that the quenched reduced model undergoes the first-order phase transition in excellent agreement with the Monte Carlo data. The quenched reduced model is shown to be equivalent to the standard Wilson theory by comparing with the string variable Wilson theory at any finite order in the loop expansion in the large-N limit.     

Evidence for muon neutrino oscillation in an accelerator-based experiment

We present results for nu(mu) oscillation in the KEK to Kamioka (K2K) long-baseline neutrino oscillation experiment. K2K uses an accelerator-produced nu(mu) beam with a mean energy of 1.3 GeV directed at the Super-Kamiokande detector. We observed the energy-dependent disappearance of nu(mu), which we presume have oscillated to nu(tau). The probability that we would observe these results if there is no neutrino oscillation is 0.0050% (4.0 sigma).     

Self-energy correction to momentum-density distribution of positron-electron pairs

Positron two-dimensional angular correlation of annihilation radiation (2D ACAR), i.e., the 2D projection of the electron momentum densities sampled by positron, in Si is employed to verify the prediction of the density functional theory within the local-density approximation (LDA). Carefully conducted test shows that the LDA introduces small but definite discrepancies to the 2D-ACAR anisotropies. Self-energy calculation using the GW method indicates that density-fluctuation contributes anisotropic momentum-density correction and thus improves the agreement between theory and experiment. These results provide valuable annotations to the arguments concerning the accuracy and validity of the LDA and GW schemes.     

Production of doubly charged helium ions by two-photon absorption of an intense sub-10-fs soft x-ray pulse at 42 eV photon energy

We report on the observation of doubly charged helium ions produced by a nonlinear interaction between a helium atom and photons with a photon energy of 42 eV which are generated with the 27th harmonic of a femtosecond pulse from a Ti:sapphire laser. The number of ions is proportional to the square of the intensity of the 27th harmonic pulse, and thus two-photon double ionization should be dominantly induced as compared with other nonlinear processes accompanying sequential ionization via a singly charged ion. This phenomenon is utilized to measure the pulse duration of the 27th harmonic pulse by using an autocorrelation technique, for the first time to our knowledge, and as a result a duration of 8 fs is found.     

Age-dependent plasticity in the superior temporal sulcus in deaf humans: a functional MRI study

Background  

Sign-language comprehension activates the auditory cortex in deaf subjects. It is not known whether this functional plasticity in the temporal cortex is age dependent. We conducted functional magnetic-resonance imaging in six deaf signers who lost their hearing before the age of 2 years, five deaf signers who were >5 years of age at the time of hearing loss and six signers with normal hearing. The task was sentence comprehension in Japanese sign language.     

Synergistic extraction of lanthanoids(III) with 2-thenoyltrifluoroacetone and benzoic acid: thermodynamic parameters in the complexation in organic phases and the hydration

In order to examine the reason why the magnitude of the synergistic effect observed in the extraction of lanthanoids(III) with a β-diketone and a monodentate Lewis base generally decreases along with increasing atomic number, the hydration number of the extracted species when lanthanoids(III) are extracted with TTA (2-thenoyltrifluoroacetone, HA) and benzoic acid (HB) into chloroform by Karl Fischer titration and the enthalpy change in complexation between LnA₃ and HB by calorimetric titration were determined across the lanthanoid series at 25 °C.It has been concluded that since the decrement of entropy change caused by the change in the number of released water molecules and in the coordination number of lanthanoids(III) upon complexation is larger than the increment of the enthalpy change, the values of the second formation constants of the complexes decrease with increasing the atomic number across lanthanoid series so that the magnitude of the synergistic extraction decreases with increasing the atomic number.