Thienoanellierte 6aλ4-Thia-1,6-diazapentalene durch baseninduzierte Dimerisierung von 5-Methyl-isothiazoliumsalzen

Thienoanneleted 6aλ⁴-Thia-1,6-diazapentalenes by Baseinduced Dimerisation of 5-Methyl-isothiazolium Salts Isothiazolium salts 2 and 3 are easily available by reaction of (Z/E)-β-thiocyanatovinyl aldehydes with primary aliphatic and aromatic amines in acetic acid or with aromatic amine hydrochlorides, respectively. Preparative advantages of this reaction are demonstrated and discussed. Reaction of 3 with secondary amines results in an unexpected formation of 6aλ⁴-thia-1,6-diazapentalenes 5 , a new typ of thiadiazapentalenes anellated with a heterocyclic ring system. The structure of 5 was evidenced by IR, UV, ¹H-, ¹³C-n.m.r. spectral data and supported by elemental analysis. By means of ¹⁵N- and ¹³C-n.m.r. spectroscopy the synthesized thiadiazapentalenes were found to be stable towards protonation.     

Hand path priming in manual obstacle avoidance: Evidence that the dorsal stream does not only control visually guided actions in real time.

According to a prominent theory of human perception and performance (M. A. Goodale & A. D. Milner, 1992), the dorsal, action-related stream only controls visually guided actions in real time. Such a system would be predicted to show little or no action priming from previous experience. The 3 experiments reported here were designed to determine whether priming exists for visually guiding the hand to targets with obstacles sometimes in the way. In all 3 experiments, priming was observed in the curvature of hand paths. Hand paths when no obstacles were present were more curved if obstacles had recently appeared than if obstacles had not recently appeared. The results also show that hand path priming was not the result of active prediction, persisted for many trials, and generalized over the workspace. The times to initiate movements also reflected the use of a sophisticated visual search strategy that took obstacle likelihood into account. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mechanism of stress-induced leakage current in MOS capacitors

Stress-induced leakage current (SILC) is examined both below and above the voltage at which the preexisting Fowler-Nordheim tunneling current dominates. Based on these results, it is argued that SILC is the result of inelastic rather than elastic trap-assisted tunneling. This clarification explains the well-known thickness dependence of the SILC at low fields that has identified it as a scaling limitation for nonvolatile memory tunnel oxide. It also explains a newly observed different thickness dependence at high fields and facilitates modeling of the electric field/voltage and trap density dependencies of the SILC     

Schlumberger's software improvement program

A corporate-wide software process improvement effort has been ongoing at Schlumberger for several years. Through the motivation efforts of a small group, productive changes have occurred across the company. We see improvements in many development areas, including project planning and requirements management. The catalysts behind these advances include capability assessments, training, and collaboration     

Low Temperature Electronic Transport in Al–Cu–Ru Quasicrystalline Alloys

Electrical resistivities of several quasicrystalline (QC) icosahedral Al–Cu–Ru alloys have been measured between room temperature and mK temperatures. None of the Al–Cu–Ru samples exhibited “insulating” behaviors in their resistivities. One sample had a large resistivity of ≈49,000 μΩ cm at room temperature. Its resistivity increased with decreasing temperatures by a factor of 3.2 and exhibited a maximum around 2 K. Fitting discrepancies between the experimental magnetoconductivity data and the weak localization and electron–electron interaction theories suggest that the weak localization theory poorly describes the electronic conduction behavior of this highly resistive quasicrystalline sample.     

Electronic Transport Properties of Speer Carbon Resistors—Experimental Results and Semi-empirical Fits

Speer carbon composition resistors, in particular the 470 and 220 1/2 W grade 1002 resistors, have been used as secondary thermometers at temperatures below 4 K for many years. Their zero field resistances have been measured between 300 K and 4 K using a dip probe. Above 10 K, the resistance behavior can be explained using a simple temperature power law, R(T) R₀/T^0.16. The resistance measurements have been extended to 0.02 K using dilution refrigerators. Between 4 K and 0.3 K, the resistances exhibited activated laws having hopping exponents y 0.5. Below 0.3 K, the 470 resistors exhibit a crossover to a weaker activated law. Crossover resistance expressions suggest that the resistances follow a Mott variable-range hopping (VRH) law below 0.05 K. The low temperature magnetoresistance (MR) data showed changes of less than ±12 % of the zero field resistance values in fields up to 10 T. Fits using the wave function shrinkage and the forward interference models gave only fair agreement with the MR data.     

Localized Deformation and Fracture in Neutron Irradiated Zircaloy-2

A detailed examination of the deformation bands and the fracture surface morphologies was made with neutron irradiated Zircaloy-2 sheet that had been prepared with similar compositions and microstructures, but with different crystallographic textures. These materials were irradiated at 600 (327°C) to fluences up to 2 x l0²¹ n/cm² (E > 1 MeV). Tests were made in simple tension and in plane strain tension at 523 (250°C) and at a strain rate of 0.05 min^-1. In the material with (0002) poles predominantly parallel to the normal of sheet sample, the specimen tested in simple tension was macroscopically deformed in a manner consistent with the expected slip direction (1120). However, within individual grains, “pencil glide” deformation was noted where the slip direction was shared by more than one slip plane. The slip planes are of the type (10―1l), where the most likely values ofl are 0 and 1. The deformation was in sharply defined bands reminiscent of Lüders bands, to other materials, where (0002) poles were tilted toward the tensile direction, deformation occurred in less localized manner. In plane strain tension, however, the same materials fractured with very little plastic deformation, but with indications that small amounts of shear deformation occurred in a direction not parallel to the basal plane. The fracture morphologies were strongly affected by texture in the simple tension tests, to plane strain, however, the fracture morphologies were determined more by the constraints of the test than by the texture of the material in spite of the large differences in fracture stress that have been observed in materials with different texture.