Research and development of cells with bellows controlled electrolyte levels Final progress report, May 11, 1965 - Apr. 1, 1966

Control of electrolyte level in sealed Ni-Cd and Ag-Cd cells with bellows actio

The Schizophrenic Spectrum of LSR 1610-0040: a Peculiar M Dwarf/Subdwarf

We present a moderate resolution (R=2000), 0.8-4.1 micron spectrum of LSR 1610-0040, a high proper motion star classified as an early-type L subdwarf by Lepine and collaborators based on its red-optical spectrum. The near-infrared spectrum of LSR 1610-0040 does not fit into the (tentative) M/L subdwarf sequence but rather exhibits a mix of characteristics found in the spectra of both M dwarfs and M subdwarfs. In particular, the near-infrared spectrum exhibits a Na I doublet and CO overtone bandheads in the K band, and Al I and K I lines and an FeH bandhead in the H band, all of which have strengths more typical of field M dwarfs. Furthermore the spectrum of Gl 406 (M6 V) provides a reasonably good match to the 0.6-4.1 micron spectral energy distribution of LSR 1610. Nevertheless the near-infrared spectrum of LSR 1610 also exhibits features common to the spectra of M subdwarfs including a strong Ti I multiplet centered at ~0.97 microns, a weak VO band at ~1.06 microns, and possible collision-induced H_2 absorption in the H and K bands. We discuss a number of possible explanations for the appearance of the red-optical and near-infrared spectrum of LSR 1610-0040. Although we are unable to definitively classify LSR 1610-0040, the preponderance of evidence suggests that it is a mildly metal-poor M dwarf. Finally, we tentatively identify a new band of TiO at ~0.93 microns in the spectra of M dwarfs.Comment: Accepted for publication in the Astronomical Journa

59Co-NMR Knight Shift of Superconducting Three-Layer NaxCoO2.yH2O

The superconducting state of NaxCoO2.yH2O with three CoO2 layers in a unit cell has been studied by 59Co-NMR. The Knight shift measured for a peak of the NMR spectra corresponding to the external magnetic field H along one of the principal directions within the CoO2 plane, exhibits a rapid decrease with decreasing temperature T below the superconducting transition temperature Tc, indicating that the spin susceptibility is suppressed in the superconducting phase, at least, for this field direction. Because differences of the superconducting properties are rather small between this three-layer NaxCoO2.yH2O and previously reported NaxCoO2.yH2O with two CoO2 layers within a unit cell, the present result of the Knight shift studies indicates that the Cooper pairs of the former system are in the singlet state as in the latter, for which the spin susceptibility is suppressed for both directions of H parallel and perpendicular to the CoO2 plane.Comment: 5 page

Magnetic and Metal-Insulator Transitions in beta-Na0.5CoO2 and gamma-K0.5CoO2 -NMR and Neutron Diffraction Studies-

Co-oxides beta-Na0.5CoO2 and gamma-K0.5CoO2 have been prepared by the Na de-intercalation from alpha-NaCoO2 and by the floating-zone method, respectively. It has been found that successive phase transitions take place at temperatures Tc1 and Tc2 in both systems. The appearance of the internal magnetic field at Tc1 with decreasing temperature T indicates that the antiferromagnetic order exists at T < Tc1, as in gamma-Na0.5CoO2. For beta-Na0.5CoO2, the transition temperatures and the NMR parameters determined from the data taken for magnetically ordered state are similar to those of gamma-Na0.5CoO2, indicating that the difference of the stacking ways of the CoO2 layers between these systems do not significantly affect their physical properties. For gamma-K0.5CoO2, the quantitative difference of the physical quantities are found from those of beta- and gamma-Na0.5CoO2. The difference between the values of Tci (i = 1 and 2) of these systems might be explained by considering the distance between CoO2 layers.Comment: 8 pages, 14 figures, 1 Tabl

Sixty original plays for primary grades

Thesis (Ed.M.)--Boston Universit

Valley-resolved electronic coherences in silicon observed by attosecond transient absorption spectroscopy

Electronic coherences are observed in silicon by attosecond transient absorption spectroscopy. Various sub-4 fs oscillations across the conduction band reveal complex couplings between valence-conduction and conduction-conduction bands indicating pathways for coherent preparation of highly excited electrons