The new mineral, vanadoallanite-(La), found in the stratiform ferromanganese deposit from the Shobu area, Ise City, Mie Prefecture, Japan, was studied using electron microprobe analysis and single-crystal X-ray diffraction methods. Vanadoallanite-(La) is a rare-earth element-rich monoclinic epidote-supergroup mineral with simplified formula CaLaV3+AlFe2+(SiO4)(Si2O7)O(OH) (Z = 2, space group P21/m) characterized by predominantly V3+ at one of three octahedral sites, M1. The crystal studied shows large V (∼8.4 V2O3 wt.%), Fe (∼13.8 Fe2O3 wt.%; Fe2+/total Fe = 0.58) and Mn (∼8.8 MnO wt.%) contents. A small amount of Ti is also present (∼1.3 TiO2 wt.%). Structural refinement converged to R1 = 2.96%. The unit-cell parameters are a = 8.8985(2), b = 5.7650(1), c = 10.1185(2) Å, β = 114.120(1)° and V = 473.76(2) Å3. The cation distributions determined at A1,A2 and M3 are Ca0.61Mn0.39, (La0.46Ce0.14Pr0.07Nd0.18)Σ0.85Ca0.15 and Fe2+0.56Mn2+0.30Mg0.06V3+0.05Fe3+0.03, respectively. On the other hand, depending on Ti assignment, two different schemes of the cation distribution at M1 and M2 can be considered: (1) M1(V3+0.58Fe3+0.34Ti4+0.08) M2(Al0.92Fe3+0.08), and (2) M1(V3+0.58Fe3+0.42)M2(Al0.92Ti4+0.08). In both cases, the dominant cations at A1, A2, M1, M2 and M3 are Ca, La, V3+, Al and Fe2+ , respectively. According to ionic radius, Ti4+ possibly prefers M2 rather than Fe3+. A large Mn2+ content at A1 also characterizes our vanadoallanite-(La). The structural change of Mn2+-rich allanite-group minerals is considered to be controlled by two main factors. One is the large Mn2+ content at A1 in vanadoallanite-(La), which modifies the topology of the A1O9 polyhedron. The other is the expansion of M3O6 and M1O6 octahedra caused by large octahedral cations, such as Fe2+ and Mn2+, at M3 and the trivalent transition elements, V3+ and Fe3+, at M1.

Several silicate-minerals, such as ardennite – Mn2+4MgAl5[Si5(As5+,V5+)O22](OH)6, Z = 2, tiragalloite – Mn2+4[Si3As5+O12(OH)], Z = 4 and medaite – Mn2+6[Si5(V5+,As5+)O18(OH)], Z = 4 possess (V5+,As5+,P5+)O4 tetrahedra. Using electron-microprobe analysis (EMPA) and single-crystal X-ray diffraction methods, the crystal chemistry of ardennite from Salam-Château, Belgium and the Vernetto mine, Italy, tiragalloite from the Gambatesa mine, Italy, and medaite from the Molinello mine, Italy and the Fianel mine, Switzerland, were studied. Structure refinements converged to R1 values of 2.10–5.67%. According to chemical analysis, the Σ(As+V+P) content increases with decreasing Si content. Thus, Si replaces pentavalent cations in tetrahedral coordination. The (As5+,V5+,P5+,Si4+)O4 tetrahedra are categorized by their connections to SiO4 tetrahedra. The (As5+,V5+,P5+,Si4+)O4 tetrahedron of ardennite is isolated, and those of tiragalloite and medaite terminate a tetrahedral chain. The <T–O> of the isolated (As5+,V5+,P5+,Si4+)O4 tetrahedron shows a positive correlation with the mean ionic radius. For (As5+,V5+,P5+,Si4+)O4 tetrahedra with one T–O–T link, <T–O> and mean ionic radius are also correlated. In addition, the longest bridging T–O bond occurs between (As,V,P,Si)O4 and the adjacent SiO4 tetrahedron. The bridging O atom is over-bonded to satisfy the charge requirement of Σ(As+V+Si).

Schäferite, NaCa2Mg2(V5+O4)3; palenzonaite, NaCa2Mn22+(V5+O4)3; berzeliite, NaCa2Mg2(As5+O4)3; and manganberzeliite, NaCa2Mn2+2(As5+O4)3, are cubic minerals with garnet structures (space group Iad) in which tetrahedrally coordinated V5+ and/or As5+ at the Z site are charge balanced by disordered Na+ and Ca2+ at the X site, and divalent Mg2+ and Mn2+ cations at the octahedrally coordinated Y site. The crystal chemistry of palenzonaite (from the Molinello and Gambatesa mines, Italy, and the Fianel mine, Switzerland), berzeliite (from Långban, Sweden, and Montaldo, Italy), and manganberzeliite (from Varenche, Italy, and the Gozaisho mine, Japan) were studied by electron microprobe analysis and single-crystal X-ray diffraction methods. Structure refinements converged to R1 values of 1.36–2.42%. The tetrahedral site in these garnet structures is mainly occupied by pentavalent As5+ or V5+ (only up to about 20% randomly distributed Si4+ is present). Charge balance is maintained by variations in the Ca/Na ratio at the X site. Heterovalent substitution (Na+ ↔ Ca2+) at the distorted square antiprism X site in vanadate- and arsenate-bearing garnets allows full occupancy of the octahedral Y site by divalent cations (primarily Mg2+ and Mn2+). There is a positive correlation between the <Z–O> and <Y–O> bond lengths and the mean ionic radii of the substituent elements, but there is no correlation between the <X–O> bond length and the variable Na/Ca site occupancy. The ionic radii of octahedrally coordinated Mg2+ and Mn2+ are such that the shared octahedral–dodecahedral edges are similar in length to the unshared octahedral edges, which is a measure of lattice distortion in garnet structures.

The structure of hibonite from Myanmar (space group P63/mmc, Z = 2, at room temperature a = 5.5909(1), c = 21.9893(4) Å), with simplified formula CaAl12O19 and composition (Ca0.99Na0.01)Σ1.00 was investigated between temperatures of 100 K and 923 K by single-crystal X-ray diffraction methods. Structure refinements have been performed at 100, 296, 473 and 923 K. In hibonite from Myanmar, Ti substitutes for Al mainly at the octahedral Al4 site and, to a lesser degree, at the trigonal bipyramidal site, Al2. The Al4 octahedra build face-sharing dimers. If Ti4+ substitutes at Al4, adjacent cations repulse each other for electrostatic reasons, leading to off-centre cation displacement associated with significant bond-length distortion compared to synthetic (Ti-free) CaAl12O19. Most Mg and smaller proportions of Zn and Si are assigned to the tetrahedral Al3 site. 12-coordinated Ca in hibonite replaces oxygen in a closest-packed layer. However, Ca is actually too small for this site and engages in a ‘rattling-type’ motion with increasing temperature. For this reason, Ca does not significantly increase thermal expansion coefficients of hibonite. The expansion of natural Ti,Mg-rich hibonite between 296 and 923 K along the x and the z axes is αa = 7.64×10–6 K–1 and αc = 11.19×10–6 K–1, respectively, and is thus very similar to isotypic, synthetic CaAl12O19 and LaMgAl11O19 (LMA).

It is now firmly established that a small anisotropy of the galactic cosmic rays exists, observable from Earth as a variation of intensity in sidereal time. The problem now is to determine more clearly the characteristics of the anisotropy and, in particular, its detailed spatial structure and how it depends upon the energy and composition of the cosmic rays. This is a very difficult task and, in the final analysis, may not be fully achievable from Earth-based observations. The purpose of the present paper is to describe briefly an installation now operating in Tasmania to provide further information on the spatial structure of the anisotropy.

Optical and near-infrared observations of novae give us useful information for understanding the diversity of nova eruptions. Classical nova V1723 Aql was discovered by F. Kabashima and K. Nishiyama on 2010 September 11. We have conducted photometric and spectroscopic observations of V1723 Aql in both optical and near-infrared (NIR) wavelength regions since its discovery. The V-band decline time by 2 mag after the maximum, t2, was ~12 d. The apparent Fe II emission lines were also seen in the optical spectra. The Rc- and Ic-band light curves exhibited rapid declines (0.16 mag d−1 in Rc) 20 days after the visual maximum, while the NIR (J, H, and Ks) showed slow decline rates (~0.07 mag d−1). This rapid reddening suggests that dust particles formed during the very early phase of the expansion in V1723 Aql.

We investigate the properties of local HI-selected galaxies detected in blind radio surveys by using semi-analytic galaxy formation models in the hierarchical structure formation scenario. By drawing a detailed comparison between the properties of the HI-selected galaxies and the quasar absorption systems, we investigate a link between the local galaxy population and the quasar absorption systems, particularly for Damped Lymanα absorption (DLA) systems (NHI ≥ 1020.3 cm−2) and sub-DLA systems (1019 < NHI < 1020.3 cm−2).

We find that DLA galaxies, in which the HI column densities are as high as those of DLA systems, contribute primarily to the population of local HI-selected galaxies at MHI ≥ 108M⊙. By contrast, in the low-mass range MHI ≤ 107M⊙, sub-DLA galaxies replace DLA galaxies as the dominant population. The HI-selected galaxies would be a strong probe of DLA/sub-DLA systems.

Extended abstract of a paper presented at Microscopy and Microanalysis 2005 in Honolulu, Hawaii, USA, July 31--August 4, 2005

Metal enrichment of intracluster medium (ICM) is reanalysed in the hierarchical galaxy formation scenario. In order to investigate metal abundances of $\alpha$ and iron-peak elements, we incorporate metal production processes by type Ia supernovae (SNe Ia) as well as type II supernovae (SNe II) into the GALFORM model of semi-analytic galaxy formation. We find that a top-heavy initial mass function (IMF) of stars with a power index $x\simeq 0.35$ for starburst is required under the constraint that the IMF for quiescent disc star formation is the Kennicutt IMF. Our model shows an only mild evolution of [Fe/H] as suggested by a recent observation.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We are currently conducting three kinds of IR surveys of star forming regions (SFRs) in order to seek for very low-mass young stellar populations. First is a deep JHKs-bands (simultaneous) survey with the SIRIUS camera on the IRSF 1.4m or the UH 2.2m telescopes. Second is a very deep JHKs survey with the CISCO IR camera on the Subaru 8.2m telescope. Third is a high resolution companion search around nearby YSOs with the CIAO adaptive optics coronagraph IR camera on the Subaru. In this contribution, we describe our SIRIUS camera and present preliminary results of the ongoing surveys with this new instrument.

Vanadium dioxide thin films (VO2) have been deposited by laser ablation. The temperature dependence of resistivity and temperature coefficient of resistance (TCR) for each deposition condition were investigated. It was clarified that the TCR at room temperature (RT) can be optimized by controlling the oxygen pressure introduced during deposition as the deposition parameter. In the result, larger TCR's at RT were observed for the oxygen deficient condition of VO2 than for oxygen-richer samples. Obtained TCR values were 0.072/K and 0.045/K at 25°C for VO2 thin films deposited onto R-cut sapphire and SiO2/Si, respectively.

We reported a waveguide-type optical switch fabricated on a Si substrate which utilized the Quantum Confined Stark Effect (QCSE). The prepared sample is an Al0.3Ga0.7As (cladding layer) / Al0.25Ga0.75As (guiding layer) double-heterostructure (DH) optical switch with a GaAs single quantum well (SQW) in the guiding layer by MOCVD. The absorption edge of the sample is measured by photocurrent method under reverse bias using a cw Ti: Sapphire laser for a light source. We measured about 10 nm shift of the absorption edge at -8 V from the sample with 8.3 nm SQW. This result demonstrates the Stark-shift effect of GaAs SQW on Si. A 2.5 μm-width ridge was formed by etching in the top cladding layer and the light traveling in the guiding layer was confined to a fundamental mode in vertical (parallel to growth direction) and horizontal direction. This switch showed 33.1 dB/mm modulation at 867 nm wavelength in -8 V bias.

The observation of 8B solar Neutrinos in the Kamiokande-II detector is presented. Based on 450 days of data in the time period of January 1987 through May 1988, the measured flux obtained with Ee ≥ 9.3 MeV was 0.46 ± 0.13 (stat) ± 0.08 (sys) of the value predicted by the standard solar model. The detector and analysis methods were improved since June 1988 and the background level has been decreased by a factor of about three since then.

Satellite imagery has substantially improved the quality of sea-Ice observation over the last decades. Therefore, for a 25-year period, a statistical study based on the monthly Arctic sea-ice data and the monthly mean 700 mbar maps of the Northern Hemisphere was carried out to establish the relationships between sea-ice conditions and the general circulation of the atmosphere. It was found that sea-ice conditions have two opposing effects on the zonal circulation intensity, depending on the season. Heavier than normal ice in winter causes stronger than normal zonal circulation in the subsequent months, whereas heavier than normal ice in the summer–fall causes weaker zonal circulation in the subsequent months. Analyzing the two sectors, the Atlantic and Pacific ones separately, a negative correlation was found, which means a heavy ice year in the Atlantic Ocean is normally associated with a light one in the Pacific Ocean and vice versa.

The possibility that primary recrystallization textures are influenced by local inhomogeneities of deformation induced in the regions of grain boundaries has been confirmed by comparing the cold rolling and the annealing textures of polycrystalline pure irons which were different in the grain size prior to cold rolling. Analyses were made for the effects of deformation on crystals, namely storage of lattice strain and orientation spread, with application of X-ray diffraction techniques, in order to elucidate the role of in homogeneities of deformation on recrystallization texture formation. Apparent correspondence was found between the orientation dependence of stored strain energy and the textural change on recrystallization. This is a scribed to oriented nucleation in high energy blocks, in the case of originally large-grain material in which the effects of inhomogeneities of deformation are small. But discrepancies arise on this basis in originally small - grain material in which the effects of inhomogeneities of deformation are thought to be considerable. The discrepancy is inferred to arise as an effect of local inhomogeneities of deformation, from the change in the trend of rotational orientation spreads from, a stable orientation and the extent of development of potential nuclei of recrystallization at high energy blocks in the orientation spreads. The change is considered to give rise to the variation in amount of microstrain distribution, which is expressed in recovery characteristics of lattice strains and in the dependence of microstrains on the column length as analyzed by following the procedure of Warren-Averbach.