Redox States of Geochemically-Enriched Shergottites as Inferred from Fe Micro-XANES Analysis of Maskelynite and Plagioclase.

第2回極域科学シンポジウム/第34回南極隕石シンポジウム 11月18日（金） 国立国語研究所 2階講

The Valence of Iron in CM Chondrite Serpentine as Measured by Synchrotron Xanes

Fe-bearing phyllosilicates are the dominant product of aqueous alteration in carbonaceous chondrites, and serpentine is the most abundant phyllosilicate in CM2 chondrites that are the most abundant carbonaceous chondrite. Browning et al. predicted that Fe(3+)/(sum of Fe) ratios of serpentine in CM chondrites should change with progressive alteration. They proposed that progressive CM alteration is best monitored by evaluating the progress of Si and Fe3+ substitutions that necessarily attend the transition from end-member cronstedtite to serpentine. Their proposed Mineralogic Alteration Index, 2-(Fe(3+)/(2-Si)), was intended to highlight and utilize the relevant ex-change information in the stoichiometric phyllosilicate formulas based upon the coupled substitution of 2(Fe(3+), Al) = Si + (Mg, Fe(2+)...) in serpentine. The value of this ratio increases as alteration proceeds. We always wanted to directly test Browning s pre-diction through actual measurements of the Fe3+ con-tent of serpentine at the micron scale appropriate to EPMA analyses (Zega et al. have measured it at much finer scale), and this test can now be made using Synchrotron Radiation X-ray Absorption Near-Edge Structure (SR-XANES). Thus, we have recently begun investigation with CMs that span a large portion of the range of observed aqueous alteration, and we first analyzed Murray, Nogoya, and ALH84029 by SR-XANES. However, we did not find clear correlation between Fe3+/(sum of Fe) ratios of serpentine and their alteration degrees. We thus analyzed serpentine in three more CMs and here report their Fe3+/(sum of Fe) ratios in comparison with our previous results

Landau (\Gamma,\chi)-automorphic functions on \mathbb{C}^n of magnitude \nu

We investigate the spectral theory of the invariant Landau Hamiltonian \La^\nu acting on the space ${\mathcal{F}}^\nu_{\Gamma,\chi}$ of $(\Gamma,\chi)$-automotphic functions on \C^n, for given real number $\nu>0$, lattice $\Gamma$ of \C^n and a map $\chi:\Gamma\to U(1)$ such that the triplet $(\nu,\Gamma,\chi)$ satisfies a Riemann-Dirac quantization type condition. More precisely, we show that the eigenspace {\mathcal{E}}^\nu_{\Gamma,\chi}(\lambda)=\set{f\in {\mathcal{F}}^\nu_{\Gamma,\chi}; \La^\nu f = \nu(2\lambda+n) f}; \lambda\in\C, is non trivial if and only if $\lambda=l=0,1,2, ...$. In such case, ${\mathcal{E}}^\nu_{\Gamma,\chi}(l)$ is a finite dimensional vector space whose the dimension is given explicitly. We show also that the eigenspace ${\mathcal{E}}^\nu_{\Gamma,\chi}(0)$ associated to the lowest Landau level of \La^\nu is isomorphic to the space, {\mathcal{O}}^\nu_{\Gamma,\chi}(\C^n), of holomorphic functions on \C^n satisfying g(z+\gamma) = \chi(\gamma) e^{\frac \nu 2 |\gamma|^2+\nu\scal{z,\gamma}}g(z), \eqno{(*)} that we can realize also as the null space of the differential operator $\sum\limits_{j=1}\limits^n(\frac{-\partial^2}{\partial z_j\partial \bar z_j} + \nu \bar z_j \frac{\partial}{\partial \bar z_j})$ acting on $\mathcal C^\infty$ functions on \C^n satisfying $(*)$.Comment: 20 pages. Minor corrections. Scheduled to appear in issue 8 (2008) of "Journal of Mathematical Physics

Tsunami generation of the 1993 Hokkaido Nansei-Oki earthquake

Heterogeneous fault motion of the 1993 Hokkaido Nansei-Oki earthquake is studied by using seismic, geodetic and tsunami data, and the tsunami generation from the fault model is examined. Seismological analyses indicate that the focal mechanism of the first 10 s, when about a third of the total moment was released, is different from the overall focal mechanism. A joint inversion of geodetic data on Okushiri Island and the tide gauge records in Japan and Korea indicates that the largest slip, about 6 m, occurred in a small area just south of the epicenter. This corresponds to the initial rupture on a fault plane dipping shallowly to the west. The slip on the northernmost subfault, which is dipping to the east, is about 2 m, while the slips on the southern subfaults, which are steeply dipping to the west, are more than 3 m. Tsunami heights around Okushiri Island are calculated from the heterogeneous fault model using different grid sizes. Computation on the smaller grids produces large tsunami height that are closer to the observed tsunami runup heights. Tsunami propagation in the nearly closed Japan Sea is examined as the free oscillation of the Japan Sea. The excitation of the free oscillation by this earthquake is smaller than that by the 1964 Niigata or 1983 Japan Sea earthquake.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43222/1/24_2004_Article_BF00874395.pd

Charge ordering and chemical potential shift in La2−x_{2-x}Srx_xNiO4_4 studied by photoemission spectroscopy

We have studied the chemical potential shift in La$_{2-x}$Sr$_x$NiO$_4$ and the charge ordering transition in La$_{1.67}$Sr$_{0.33}$NiO$_4$ by photoemission spectroscopy. The result shows a large ($\sim$ 1 eV/hole) downward shift of the chemical potential with hole doping in the high-doping regime ($\delta \gtrsim$ 0.33) while the shift is suppressed in the low-doping regime ($\delta \lesssim$ 0.33). This suppression is attributed to a segregation of doped holes on a microscopic scale when the hole concentration is lower than $\delta \simeq 1/3$. In the $\delta = 1/3$ sample, the photoemission intensity at the chemical potential vanishes below the charge ordering transition temperature $T_{\rm CO}=$ 240 K.Comment: 5 pages, 4 figure

On the tau-functions of the Degasperis-Procesi equation

The DP equation is investigated from the point of view of determinant-pfaffian identities. The reciprocal link between the Degasperis-Procesi (DP) equation and the pseudo 3-reduction of the $C_{\infty}$ two-dimensional Toda system is used to construct the N-soliton solution of the DP equation. The N-soliton solution of the DP equation is presented in the form of pfaffian through a hodograph (reciprocal) transformation. The bilinear equations, the identities between determinants and pfaffians, and the $\tau$-functions of the DP equation are obtained from the pseudo 3-reduction of the $C_{\infty}$ two-dimensional Toda system.Comment: 27 pages, 4 figures, Journal of Physics A: Mathematical and Theoretical, to be publishe

Mineralogy and crystallography of vein metals in the Almahata Sitta ureilite.

第2回極域科学シンポジウム/第34回南極隕石シンポジウム 11月18日（金） 国立国語研究所 2階講

Two-Dimensional Molecular Patterning by Surface-Enhanced Zn-Porphyrin Coordination

In this contribution, we show how zinc-5,10,15,20-meso-tetradodecylporphyrins (Zn-TDPs) self-assemble into stable organized arrays on the surface of graphite, thus positioning their metal center at regular distances from each other, creating a molecular pattern, while retaining the possibility to coordinate additional ligands. We also demonstrate that Zn-TDPs coordinated to 3-nitropyridine display a higher tendency to be adsorbed at the surface of highly oriented pyrolytic graphite (HOPG) than noncoordinated ones. In order to investigate the two-dimensional (2D) self-assembly of coordinated Zn-TDPs, solutions with different relative concentrations of 3-nitropyridine and Zn-TDP were prepared and deposited on the surface of HOPG. STM measurements at the liquid-solid interface reveal that the ratio of coordinated Zn-TDPs over noncoordinated Zn-TDPs is higher at the n-tetradecane/HOPG interface than in n-tetradecane solution. This enhanced binding of the axial ligand at the liquid/solid interface is likely related to the fact that physisorbed Zn-TDPs are better binding sites for nitropyridines.