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The magnetic and transport properties of YbIrGe and LuIrGe have been investigated. YbIrGe with the TiNiSi-type orthorhombic structure is an antiferromagnet with T N = 2.4 K . Magnetic susceptibility χ(T) of YbIrGe shows a strong anisotropy which changes from the easy-plane type within the ab-plane above 100 K to the easy-axis type along the b-axis at lower temperatures. χ(T) along the a-axis makes a kink at TN in contrast to T-independence of χ(T) along b- and c-axis below TN. We propose that the Yb magnetic moments couple antiparallel in the direction of the a-axis as a magnetic structure below TN. The magnetic entropy gain at TN was released by 85% of the expected value of Rln 2 at the maximum. Therefore, YbIrGe may not be classified as a typical heavy fermion compound.

Using the computer simulation technique various properties of interstitial clusters (bundle of crowdions) in Fe has been investigated. The actual shapes of the hexagonal loops were studied in detail and it was found that the direction of each segment of a loop depends upon the loop size; that is, in smaller loops 〈1 1 1〉 direction is preferred and in larger loops 〈1 1 2〉 direction is realized, resulting in the higher Peierls stress for smaller loops and lower Peierls stress for larger loops. The behavior of the thermally activated motion of loops has been studied by the MD method, showing that the small loop I19 moved along 〈1 1 1〉 direction at 100 K under the aid of energy deposition 10 eV in a rather uniform way without clear kink formation.

Studies on bias mechanisms, such as the dislocation bias and production bias have so far been made in the Fe and Ni model crystals. In the present work the interaction between an edge dislocation and interstitial clusters has been mainly studied by computer simulation from the viewpoint of the production bias for Fe and Ni. Capture zones for interstitial clusters In (bundles of n crowdions, n=1, 2, 3, 5) to an edge dislocation line have been obtained, with the definition of the capture zone as the region where the binding energy is larger than kT=0.067 eV (T=500 °C). This shows increasing capture areas on the expansion side of the edge dislocation line with increasing size of interstitial clusters both in Fe and Ni. The energy change from the as-trapped state of the interstitial cluster to the absorbed state into the edge dislocation core was also calculated. This showed that the final stable configuration is a jogged state in Fe. This is also correct in Ni but only when the size of the interstitial cluster is larger than a certain value. These results give a confirmed basis to the production bias mechanism.

A high-spin isomeric beam line has been constructed at RIKEN based on the inverse kinematics of fusion–evaporation reactions. The beam line provides high-spin isomers as secondary beams, whose intensity is more than 10 5 sec −1 . The characteristics and the present status of the beam line are described.

In order to investigate the fundamental aspects of damage evolution under irradiation computer simulations of the interaction between a dislocation and point defects such as a self-interstitial atom (SIA), a vacancy and interstitial clusters have been performed for various configurations. It is found both in Fe and Ni that a crowdion with axis parallel to the Burgers vector of an edge dislocation interacts more strongly than those with other axis orientations. The same tendency was seen for the dumbbell. The capture range (capture area) within which SIAs are trapped by an edge dislocation is larger for Ni than for Fe, and that for vacancies is much smaller than that for SIAs, suggesting that the bias factor in Ni is larger than that in Fe.

Atomic structures of interstitial type dislocation loops and the interaction between these loops and an edge dislocation have been investigated for Fe and Ni by means of computer simulation in order to understand the basic feature of the damage structure evolution during irradiation which provides cascade formation of defects. Clusters of crowdions or dumbbells were placed in the model lattices and final structures were observed after full relaxation. It is found that in the case of clusters of crowdions, relaxation of the structure, namely, split of strain concentration for each crowdion in the cluster occurs with increasing the number of crowdions in one cluster, i.e., beyond about ten, and this split structure indicates the transition to dislocation loops, because a straight edge dislocation has the same split nature both in Fe and Ni. In the study of the interaction between an initial cluster and an edge dislocation it is found that a stacking fault of an extended edge dislocation is heavily deformed by the presence of an interstitial cluster just below the slip plane. Finally the critical stress for the motion of an interstitial loop, that is, Peierls stress, for the dislocation loop was investigated and it is found that as the loop size increases, Peierls stress decreases and approaches the level for a straight edge dislocation.

Positron lifetime calculations have been performed on vacancy clusters (stacking fault tetrahedra (SFT), vacancy loops), such clusters on dislocation line, interstitial clusters, such clusters on a dislocation line and dislocation line itself in order to investigate the so-called intermediate lifetimes observed in the experiments, namely, positron lifetimes between that at a matrix and that at a single vacancy. Before lifetime calculations, various defects were constructed in the model lattices and were relaxed completely to obtain the stable atomic structure by using N -body potentials. Then positron lifetime calculation was carried out for each defect. It was shown that positron lifetime for a SFT in Ni dependes on its size and becomes smaller with increasing the size. The positron wave function is mainly localized at the corner of a SFT, which gives rather lifetime, e.g., 130 ps for V 28 , but when the cluster size is small, e.g., less than 10 vacancies, it gives a rather longer lifetime, e.g., 177 ps for V 6 because of the wave function localized at the inner space of a cluster. These behaviours are consistent with the experimental results. It was also found that the positron lifetime on a dislocation line and that at a jog are short (113 and 119 ps, respectively for Ni, 117 and 117 ps, respectively for Fe), close to the lifetime at matrix (110 ps for both Ni and Fe) and in these cases trapping potentials for a positron are shallow both for Ni and Fe.

Atomic structure and dynamic behavior of small interstitial clusters (dislocation loops) in Fe and Ni have been studied by means of both the static relaxation method and the molecular dynamics (MD) method in order to clarify their role in the evolution of damage structure during irradiation, especially in the so-called production bias effect through one-dimensional migration and sink efficiency to dislocations. Model crystals were constructed by using N-body potentials and stable atomic structures of small interstitial clusters, i.e., bundle of crowdions were obtained. It was found that each crowdion in the cluster has a split structure when the number of crowdions in the cluster is larger than 10. Dynamic behavior of the loop, e.g., the interaction with a crowdion on a (I I 1 loop axis was also investigated as a function of time by the MD method. It was shown that a small interstitial cluster, e.g., I 19 in Fe is very mobile under the interaction with a crowdion, which shows that this interstitial cluster I 19 has already the property of a dislocation loop of edge character and low Peierls potential for the motion of this loop, which is consistent with the straight edge dislocation in Fe.

From the seeds of Trichilia elegans ssp. elegans , six new limonoids, four of which possess the uncommon seco -A, B and D carbocyclic rings, have been isolated, together with two known limonoids-kihadanin A and B and 3-O-β- d -glucopyranosyl-sitosterol . The structures of these compounds have been established on the basis of 1D and 2D NMR spectroscopic techniques.

Oxygen adsorption on a W(100) surface has been investigated by the method consisting of surface photoabsorption measurement and analysis in terms of surface dielectric function. Reflectance variation of p-polarized light incident near the Brewster angle was measured in the photon-energy range from 1.6 to 5.0 eV, from which variation of the surface dielectric function for electric field tangential to the surface is then derived. The result indicates that optical transitions above 4.5 eV and below 2.0 eV are suppressed, and two optical transitions appear around 2.5 and 4.0 eV when coverage is less than 0.7 ML, whereas the transitions below 2.6 eV decreases above 0.9 ML. The electronic states relevant to these transitions are reasonably interpreted with the existing results of ultraviolet photoemission and inverse photoemission studies, which demonstrates the validity of this method.

Using the embedded atom type many body potentials for iron and copper, the lattice relaxation around copper impurity atoms in iron has been performed. The stable configuration of atoms around copper and copper vacancy complexes in FeCu alloy was simulated. By introducing a positron into the relaxed lattice of FeCu binary alloy with and without a vacancy, positron lifetimes have been calculated. The positron lifetime in a relaxed FeCu matrix was 119 ps, while in a relaxed Cu-vacancy pair it was 168 ps. The latter, which is shorter than the positron lifetime in a single vacancy, is in good agreement with the experimental lifetime observed in FeCu alloy irradiated with electrons at low temperature.

In order to obtain information on the bias factor in void swelling in metals, computer simulation in a model lattice has been performed for the interaction between a dislocation, or a dislocation loop and point defects in both fcc (Au) and bcc (Fe) metals. Not only a straight dislocation but also a jogged dislocation was chosen for the calculation of the interaction. In fcc metal, the calculation was made for the interaction between an extended dislocation and point defects. The effective interaction range, L, was determined for all the cases, and from these values the so-called bias factor was obtained as 55 and 19% for fcc (Au) and bcc (Fe) metals, respectively in the case of a straight dislocation. Almost no difference for this range L was seen between a dislocation without a jog and that with a jog. However, sink efficiency is considered to be higher for a jogged dislocation than a straight one. A comparatively small bias factor, about 8%, was obtained for the case of a dislocation loop and point defects in the fcc lattice.

A windowless gas target was developed for the production of secondary high-spin isomer beams (HSIB). An 16 O target in the compound form of CO2 gas was used to produce a 145 m Sm beam by using an 16 O ( 136 Xe , 7n) 145 m Sm reaction. The target gas pressure was kept constant at 50 Torr. A target thickness of about 1 mg/cm2 was achieved with a 10 cm target length. Gas was recirculated and the consumption was very little.

We have performed physical property measurements of clathrate-type silver oxide: Ag6O8AgNO3, having a face-centered cubic structure with a space group of Fm 3 ¯ m . We examined the temperature dependence of heat capacity, electrical resistivity and magnetic susceptibility measurements. We confirmed the superconducting state and estimated that the upper critical magnetic field: Hc2 was to be about 710 Oe by the electrical resistivity measurements under various magnetic fields.

A new type of polarimeter has been built for protons between 20 and 84 MeV. It is a ray trace type with a multifoil of carbon, multiwire proportional chambers and plastic scintillators. The polarimeter distinguishes between elastic and inelastic scattering from carbon foil and has a large solid angle acceptance (∼ 470 msr) from the carbon foil. The effective analyzing power and the effective efficiency for practical use are estimated at 0.84 and 1.7 × 10−4 in the vicinity of 60 MeV, respectively. To evaluate these values, cross sections and analyzing powers for p—C elastic scattering have been measured for laboratory scattering angles between 15° and 80° at 19 energies from 21.1 to 83.8 MeV.

The double-differential cross section d2σ/dΩ dE, analyzing power Aγ, polarization Py' and polarization transfer coefficient Ky'y were measured for the ( d , p X ) reaction with 65 MeV deuterons for 12C at 14.0° and for 58Ni at 7.0°, 14.0°, 20.5° and 40.0°. The experimental data were analyzed within the framework of the post-form DWBA appropriate for the “spectator breakup”, and the preequilibrium exciton model together with the evaporation mode. The experimental angular distributions are well explained by taking account for these processes over the whole proton energy region observed.

Inelastic scattering exciting the 2+ and 4+ members of the Kπ=2+ γ-vibrational band in 152, 154Sm, 160Gd, 164Dy, 166, 168Er, 176Yb, 182, 184W and 192Os has been measured with 65 MeV polarized protons. The quadrupole (Y22) and hexadecapole (Y42) transition strengths to the γ-vibrational band have been extracted systematically for the first time. They show strong mass number dependences, which are explained qualitatively by a simple geometrical picture.