Determination of spherosiloxane cluster bonding to Si(100)-2 x 1 by scanning tunneling microscopy

Scanning tunneling microscopy is used to determine the bonding geometry of the spherosiloxane cluster, H(8)Si(8)O(12) , on Si(100)-2 x 1. The images obtained are consistent with monovertex bonding to the Si(100)-2 x 1 surface via activation of a single Si-H bond. Filled and empty state images show good agreement with calculations of the electron density distribution of the cluster as well as the Psi(2) highest occupied molecular orbital and lowest unoccupied molecular orbital surface plots of the cluster.     

Synthesis of chloro (diethylalkoxyphosphine) gold (I) salts and their subsequent conversion to s-diethylalkoxyphosphine gold 2,3,4,6-tetra-o-acetyl-thio-β-D-glucopyranosides

A novel alkoxy-interchange leqding to a variety of alkoxy phosphine-gold-chlorides from one common starting material is reported.     

Conformations of proline-containing cyclic peptides. II. Asymmetric solution conformations of cyclo-(L-Pro2-Gly)2 and its alkaline-earth metal complexes as studied by NMR spectroscopy

By ¹H and ¹³C NMR methods, the title peptide, either free or complexed with metal ions, is shown to preferentially assume asymmetric solution conformations. Spectral data strongly suggest the occurrence of an unusual β-turn with two Pro residues in consecutive corner positions.     

The basic equations of the dynamics of the continuous distribution of dislocations III. special problems

The basic equations of the dynamics of the continuous distribution of dislocations analogical to Maxwell equations are derived in a series of papers [I, II, III]. The analogy of the elastic and electromagnetic fields is analyzed. In part [III] some special problems are discussed, such as the density of the forces acting on the dislocations, the energy dissipation during the movement of dislocations, which is expressed by an equation analogical to Ohm's law. The equations derived in the previous parts in four-dimensional symbolics are considered in the three-dimensional differential and integral form. It is found that in special cases the relations become the known ones of elastodynamics, hydrodynamics and the static theory of the continuous distribution of dislocations. It is found that Kröner's method of integrating the equations of the dislocation field by means of so-called incompatibility tensors is analogical to the integration of the Maxwell equations by means of Hertz vectors. The analogy between the elastic dislocation field and the electromagnetic field is discussed in detail.

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Electronic structure of PdO studied by photoemission (XPS,UPS)

In this paper we present the results of photoemission studies (XPS and UPS) performed on a polycrystalline surface of PdO. The electron density of states (EDOS) deduced both from XPS and UPS (He_I and He_II) are very similar. The valence band of PdO, which differs significantly from the Pd one, can be built up by four structures located at 0.5 eV, 2.2eV, 4.5 eV and 6.5 eV below E_F. The various electronic contributions (p or d) in the band are considered and, in order to explain our spectra, we discuss several hypothesis taking into account the possible existence of satellite lines or crystal field effects. Our XPS and UPS spectra show that the energy bands of PdO are narrow (～ 2–3 eV), moreover the energy shift of the core levels (|ΔE^F_B| = 2 eV) is important : these results suggest that the correlations between the d electrons may be important in PdO.     

Nuclear spin-lattice and nuclear spin-spin relaxation time measurements in EuB6 at low temperatures using the spin-echo technique

Experimental results on the nuclear spin-lattice and nuclear spin-spin relaxation times in the ferromagnetic EuB₆ at temperatures below 4·2 K are presented using the external magnetic field,H _ext, in the range of 0 ⩽H _ext ⩽ 10 kG. Nuclear spin-spin relaxation time computed on the basis of the Suhl-Nakamura process turns out to be 3·2μs, which compares well with the experimental value 11·1μs obtained with the 10 kG magnetic field at 1·7 K. It is found that in the ferromagnetic EuB₆,T ₁ is approximately 5 × 10³ times larger thanT ₂ at 1·7 K with the 10 kG magnetic field. Thus the effect ofT ₁ onT ₂ can be neglected. From the experimental value ofT ₂, the value of the homogeneous line broadening is found to be 14 kHz. The corresponding value obtained from the cw method is 175 kHz. This evidently shows the presence of the inhomogeneous line broadening in the cw NMR.     

A new gas volumetric determination of the nitrate ion

The gas volumetric determination is based on the thermal decomposition of ammonium nitrate which is carried out in a fused ammonium hydrogensulphate—ammonium sulphate mixture placed in a two-step reactor. The method is easily applicable for the analysis of solid inorganic nitrates, and can also be used for solutions.     

The application of the thermodynamics of irreversible processes to welding arcs

The self-regulation of an inert gas shielded metal welding arc is dealt with briefly. A thermodynamic equation is derived for the self-regulation of such an arc.

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