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  • Author: T. Fukuda x
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Abstract

The superstructure of tetrataenite, FeNi from the Saint Severin meteorite was determined using X-ray diffraction data from a conventional X-ray source and synchrotron radiation. Lattice constants of tetrataenite show clearly tetragonal symmetry; a = 3.581(2) Å, b = 3.582(2) Å, c = 3.587(2) Å, α = 90.03(3)°, β = 90.04(3)° and γ = 90.00(3)°. The structure, however, is monoclinic. The space group may be Pm. The atomic coordinates and the temperature were determined by data from conventional X-ray diffraction. The ordering of Fe/Ni was determined by refinement of site occupancies of the atoms applying the difference of anomalous scattering factors of Fe and Ni with synchrotron radiation λ = 1.746 Å. The tetrataenite from the Saint Severin meteorite does not show perfect ordering of Fe and Ni. It still contains 15% disorder of Fe/Ni on average.

This paper proposes a novel adaptation method for behavior-based locomotion robot. Utilization of the hierarchical behavior controller concept makes the controller designing process easier and shorter, because the designer can deal with behavior controllers for simple behaviors independently, and coordinate those behavior controllers in order for a robot to perform the objective behavior after finishing the design of the fundamental behavior controllers. Some problems are still remaining. One is how to adjust the behavior coordinator when the objective behavior or robot parameters are slightly changed. We propose a novel method to adjust the behavior coordinator against some changes. This method measures the effects of the fundamental behavior controllers to the total behavior, and changes the activation values for them in fewer trials. This proposed method is applied to the real brachiation robot control. This brachiation robot has redundant mechanism to locomote from branch to branch with 14 actuators like a long-armed ape.

Abstract

In order to determine the electric quadrupole moment of the short-lived β-emitter 41Sc from the quadrupole coupling constant in TiO2 , we measured the field gradient by detecting the Fourier-Transformed-NMR of stable isotope 45Sc doped in TiO2. Also, in order to study the electronic structure of impurities systematically, EFGs were measured for 45Sc, 49Ti and 93Nb in a TiO2 ingle single crystal.

The alignment correlation terms in the β-ray angular distributions from the purely spin aligned mirror pair 12B(Iπ= 1+ T1/2 = 20.2ms) and 12N(Iπ = 1+,T1/2 = 11.0ms)were precisely measured to place a new limit on the G-parity conservation law. For the creation of the alignment, the spin manipulation technique was applied, which utilized the nuclear quadrupole interactions. The - parity violating induced tensor coefficient was determined to be 2MfT/fa = -0,15 ± 0,12 ± 0,05 (theor.), which is consistent with the theoretical prediction based on QCD in which 2MfT/fA is proportional to the mass difference between up and down quarks which constitute the nucleon. Also determined the axial charge to be y= 4,90±0,10 (90% CL). From the result, we have found that the nucleon mass inside the nucleus is reduced (16 4)% relative to the free nucleon mass