We present a detailed study of line structure in early to late-time spectra of Supernova (SN) 1993J. Spectra during the nebular phase, but within the first two years after explosion, exhibit small-scale structure in the emission lines of some species, notably oxygen and magnesium, showing that the ejecta of SN 1993J are clumpy. On the other hand, a lack of structure in emission lines of calcium...

We present a single epoch of high signal-to-noise ratio spectropolarimetry of the Type Ia supernova (SN Ia) 2004S taken nine days after maximum light. The flux spectrum is normal, but with the additional presence of high-velocity (HV) line features in both Ca II and Fe II. The object shows continuum polarization at the 0.4% level in the red, a value which appears to be typical of SNe Ia. The co...

The Sn(IV) atom in the title compound, [Sn(C(4)H(9))(2)(C(18)H(11)BrN(2)O(3))], shows a distorted cis-C(2)NO(2)Sn trigonal-bipyramidal coordination. One of the butyl chains is disordered over two sites in a 0.60 (1):0.40 (1) ratio.

0021-9517/$ see front matter 2010 Elsevier Inc. A doi:10.1016/j.jcat.2010.01.016 * Corresponding author. Fax: +1 510 642 4778. E-mail address: [email protected] (A.T. Bel The dehydrogenation of ethane to ethene on Sn-promoted Pt supported on calcined hydrotalcite, PtSn/ Mg(Al)O, was investigated with the aim of understanding the effects of Sn on the local environment of the dispersed Pt, ...

We have determined elemental abundance ratios in the core of the Perseus cluster for several elements. These ratios indicate a central dominance of SN Ia ejecta similar to that found for A496, A2199 and A3571 (Dupke & White 2000a). Simultaneous analysis of ASCA spectra from SIS1, GIS 2&3 shows that the ratio of Ni to Fe abundances is ∼ 3.4 ± 1.1 times Solar within the central 4. This ratio is c...

The tetra-nuclear title compound, [Sn4(CH3)8(C3H7O)2O2(C3H4N3S)2], lies about a center of inversion; the mol-ecule features a three-rung-staircase Sn4O4 core in which two Sn(IV) atoms are bridged by the 4-methyl-5-sulfanyl-idene-4,5-dihydro-1H-1,2,4-triazol-1-ide group. The negatively charged N atom of the group binds to the terminal Sn(IV) atom at a shorter distance [Sn-N = 2.236 (2) Å] compar...

The Cu-Sn metallurgical soldering reaction in two-segmented Cu-Sn nanowires is studied by in situ transmission electron microscopy. By varying the relative lengths of Cu and Sn segments, we show that the metallurgical reaction results in a Cu-Sn solid solution for small Sn/Cu length ratio while Cu-Sn intermetallic compounds (IMCs) for larger Sn/Cu length ratios. Upon heating the nanowires to ∼5...

where Z = {Zn;n = 1, 2, . . .} is a non-degenerate, zero mean Gaussian process representing the noise and S = {Sn;n = 1, 2, . . .} and Y = {Yn;n = 1, 2, . . .} are stochastic processes representing input signals and output signals, respectively. The channel is with noiseless feedback, so Sn is a function of a message to be transmitted and the output signals Y1, . . . , Yn−1. The signal is subje...