4,104 research outputs found

    Synthesis and Characterization of platinum – selenium Derivatives: X-ray Structure of \u3cem\u3etrans\u3c/em\u3e-Pt(Pet\u3csub\u3e3\u3c/sub\u3e)\u3csub\u3e2\u3c/sub\u3e(SePh)\u3csub\u3e2\u3c/sub\u3e

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    The crystal structure of trans-[((bis)triethylphosphine)(bis(phenylselenato))platinum (II)] has been determined by single crystal X-ray diffraction. Crystallization occurs in the triclinic space group P-1 (No. 2) with a = 8.9964(2) Å, b = 11.5103(2) Å, c = 14.9335(3) Å; α = 85.8750(10)°, β = 72.5350(10)°, γ = 68.4450(10)°. Details of the structure and spectroscopic results are presented and discussed and comparisons are made with related square planar platinum (II) structures

    Study of bonding methods for flip chip and beam leaded devices

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    The results are presented of a comprehensive study and evaluation for the bonding of flip chip and beam leaded devices onto hybrid microcircuit substrates used in high reliability space applications. The program included the evaluation of aluminum flip chips, solder (silver/tin) bump chips, gold beam leaded devices, and aluminum beam leaded devices

    \u3cem\u3eN\u3c/em\u3e-Methylbenzothiazole-2(3\u3cem\u3eH\u3c/em\u3e)-selone, C\u3csub\u3e8\u3c/sub\u3eH\u3csub\u3e7\u3c/sub\u3eNSSe

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    The crystal structure of N-methyl1,3-benzothiazole-2(3H)-selone, (mbts) has been studied to estimate the changes in the molecular geometry of the mbts ligand upon coordination. Hypervalent complexes of mbts with TeII and II have been studied by us previously. A significant elongation of the Se=C bond [from 1.817 (7) in mbts to 1.85-1.88 Ã… in the complexes] was found, but there were no significant changes in the other geometric parameters of the ligand. The only other bond-length decrease of note was for SeC-NMe [from 1.35 (1) in mbts to 1.32-1.34 Ã… in the complexes]. Thus, only the amino group takes part in electron redistribution upon coordination

    Bromobis(Diethyldithiocarbamato)(4-Methoxyphenyl)Tellurium(IV)

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    The crystals of the TeIV complex p-CH3OC6H4Te(Et2NCS2)2Br are isomorphous with those of the the iodine and mixed iodine/bromine analogues previously investigated. The structure is pentagonal bipyramidal at the Te atom with four S atoms [Te-S 2.618-2.721 (1) Å] and the Br atom [Te-Br 2.943 (1) Å] in equatorial positions. The p-methoxyphenyl group is axial [Te-C 2.147 (3) Å]. The second axial position is approached by a Br atom of a centrosymmetrically related complex [TeBr 3.423 (1) Å, C-TeBr 173.1 (1)°] so that the molecules are joined into centrosymmetric pairs by this weak secondary coordination

    NASA micromin computer Monthly progress letter, Jan. 1967

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    Microminiature circuit development for flight control computer

    Self Calibration of Tomographic Weak Lensing for the Physics of Baryons to Constrain Dark Energy

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    Numerical studies indicate that uncertainties in the treatment of baryonic physics can affect predictions for shear power spectra at a level that is significant for forthcoming surveys such as DES, SNAP, and LSST. Correspondingly, we show that baryonic effects can significantly bias dark energy parameter measurements. Eliminating such biases by neglecting information in multipoles beyond several hundred leads to weaker parameter constraints by a factor of approximately 2 to 3 compared with using information out to multipoles of several thousand. Fortunately, the same numerical studies that explore the influence of baryons indicate that they primarily affect power spectra by altering halo structure through the relation between halo mass and mean effective halo concentration. We explore the ability of future weak lensing surveys to constrain both the internal structures of halos and the properties of the dark energy simultaneously as a first step toward self calibrating for the physics of baryons. This greatly reduces parameter biases and no parameter constraint is degraded by more than 40% in the case of LSST or 30% in the cases of SNAP or DES. Modest prior knowledge of the halo concentration relation greatly improves even these forecasts. Additionally, we find that these surveys can constrain effective halo concentrations near m~10^14 Msun/h and z~0.2 to better than 10% with shear power spectra alone. These results suggest that inferring dark energy parameters with measurements of shear power spectra can be made robust to baryonic effects and may simultaneously be competitive with other methods to inform models of galaxy formation. (Abridged)Comment: 18 pages, 11 figures. Minor changes reflecting referee's comments. Results and conclusions unchanged. Accepted for publication in Physical Review
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