The Structures of Four Complexes of 2,2,6,6-Tetramethyl-3,5- -heptanedione Containing One, Four, Four and Nine Cu(II) Ions

The structures of bis-(2,2,6,6-tetramethyl-3,5-heptanedionato) Cu(II) 1, di-fts-methoxy-di-μ-methoxy-tetrakis [ (2,2,6,6-tetramethy 1 ~ -3,5-heptanedionato)Cu(II)] 2, μ4-oxa-bispyrazolatotetrakis[(2,2,6,6- -tetramethyl-3,6-heptanedionato)Cu(II)] 3, and hexa-μ3-hydroxy- -μ6-(hydrogendioxo-0,0\u27)-nonakis[(2,2,6,6-tetramethyl-3,5-heptanedionctto) Cu(II)] 4 were determined by X-ray diffraction techniques. Compound 1 is a planar molecule with weak packing interactions and high thermal motion due to the interactions between the bulky t-butyl groups. The observed density is only 1.14 Mgm-s. Compound 2 is a step tetramer concenptually derived from squareplanardimers in which the axial site of one Cu(II) ion in each dimer is occupied by a bridging oxygen from an adjacent dimer. Compound 3 has four Cu(II) ions tetrahedrally coordinated to a central oxygen atom. Compound 4 has six Cu(II) ions occupying the corners of a trigonal prism and three lying above the rectangular faces. Six hydroxyl ions each coordinate three Cu(II) ions, one from each end of the prism and one from the face. In the center is an (0-H ... Of3 unit which trigonally binds the Cu(II) ions on each end of the prism. The bulky t-butyl groups in the four complexes effectively isolate the central Cu(II) ions from any intermolecular interactions

Apollo experience report guidance and control systems: Primary guidance, navigation, and control system development

The primary guidance, navigation, and control systems for both the lunar module and the command module are described. Development of the Apollo primary guidance systems is traced from adaptation of the Polaris Mark II system through evolution from Block I to Block II configurations; the discussion includes design concepts used, test and qualification programs performed, and major problems encountered. The major subsystems (inertial, computer, and optical) are covered. Separate sections on the inertial components (gyroscopes and accelerometers) are presented because these components represent a major contribution to the success of the primary guidance, navigation, and control system

Circuit enhances vertical resolution in raster scanning systems

Circuit enhances vertical resolution in electron beam, raster scanning systems exhibiting aperture distortion in the vertical direction. A sensitized area /image/ produces a video output when the scan beam nears it, which causes vertical elongation in the reconstructed images of all sensitized areas on the surface

The Structures of Four Complexes of 2,2,6,6-Tetramethyl-3,5- -heptanedione Containing One, Four, Four and Nine Cu(II) Ions

The structures of bis-(2,2,6,6-tetramethyl-3,5-heptanedionato) Cu(II) 1, di-fts-methoxy-di-μ-methoxy-tetrakis [ (2,2,6,6-tetramethy 1 ~ -3,5-heptanedionato)Cu(II)] 2, μ4-oxa-bispyrazolatotetrakis[(2,2,6,6- -tetramethyl-3,6-heptanedionato)Cu(II)] 3, and hexa-μ3-hydroxy- -μ6-(hydrogendioxo-0,0\u27)-nonakis[(2,2,6,6-tetramethyl-3,5-heptanedionctto) Cu(II)] 4 were determined by X-ray diffraction techniques. Compound 1 is a planar molecule with weak packing interactions and high thermal motion due to the interactions between the bulky t-butyl groups. The observed density is only 1.14 Mgm-s. Compound 2 is a step tetramer concenptually derived from squareplanardimers in which the axial site of one Cu(II) ion in each dimer is occupied by a bridging oxygen from an adjacent dimer. Compound 3 has four Cu(II) ions tetrahedrally coordinated to a central oxygen atom. Compound 4 has six Cu(II) ions occupying the corners of a trigonal prism and three lying above the rectangular faces. Six hydroxyl ions each coordinate three Cu(II) ions, one from each end of the prism and one from the face. In the center is an (0-H ... Of3 unit which trigonally binds the Cu(II) ions on each end of the prism. The bulky t-butyl groups in the four complexes effectively isolate the central Cu(II) ions from any intermolecular interactions

The significance of seniority for women managers’ interpretations of organizational restructuring

This paper examines the impact of restructuring within the transport and logistics sector on women managers working at senior and less senior (middle/junior management) levels of the organization. The majority of women experienced increased performance pressures and heavier workloads as well as an increase in working hours. At the same time, there were pressures to work at home (i.e. week-ends and evenings) and reduced opportunities to work from home (i.e. during normal office hours). Management level emerged as an important factor in how these changes were interpreted. Senior managers perceived more positive outcomes in terms of increased motivation and loyalty. Despite a longer working week, they were less likely to report low morale as an outcome from long hours. In fact, irrespective of management level, women working shorter hours were more likely to report low morale as an outcome. Results are discussed in relation to literature on restructuring and careers, in terms of perceptual framing and in relation to different levels of investment in the organization

Cluster Approximation for the Contact Process

The one-dimensional contact process is analyzed by a cluster approximation. In this approach, the hierarchy of rate equations for the densities of finite length empty intervals are truncated under the assumption that adjacent intervals are not correlated. This assumption yields a first order phase transition from an active state to the adsorbing state. Despite the apparent failure of this approximation in describing the critical behavior, our approach provides an accurate description of the steady state properties for a significant range of desorption rates. Moreover, the resulting critical exponents are closer to the simulation values in comparison with site mean-field theory.Comment: 9 pages, Latex format, 2 postscript figure

Random-cluster representation of the Blume-Capel model

The so-called diluted-random-cluster model may be viewed as a random-cluster representation of the Blume--Capel model. It has three parameters, a vertex parameter $a$, an edge parameter $p$, and a cluster weighting factor $q$. Stochastic comparisons of measures are developed for the `vertex marginal' when $q\in[1,2]$, and the `edge marginal' when q\in[1,\oo). Taken in conjunction with arguments used earlier for the random-cluster model, these permit a rigorous study of part of the phase diagram of the Blume--Capel model

Determination of the Axial-Vector Weak Coupling Constant with Ultracold Neutrons

A precise measurement of the neutron decay $\beta$-asymmetry $A_0$ has been carried out using polarized ultracold neutrons (UCN) from the pulsed spallation UCN source at the Los Alamos Neutron Science Center (LANSCE). Combining data obtained in 2008 and 2009, we report $A_0 = -0.11966 \pm 0.00089_{-0.00140}^{+0.00123}$, from which we determine the ratio of the axial-vector to vector weak coupling of the nucleon $g_A/g_V = -1.27590_{-0.00445}^{+0.00409}$.Comment: 5 pages, 2 figure