Synthesis and characterization of dinuclear p-, m- and o-xylyl bridged complexes of molybdenum and tungsten. The crystal structures of μ-p-xylyl- bis(η-pentamethyl-cyclopentadienyltri- carbonylmolybdenum) and μ-m-xylyl-bis(η- pentamethylcyclopentadienyltricarbonyltungsten)

The reactions of η⁵-Cp^*M(CO)₃Na (M = Mo, W) with ,′-p-, m- and o-dichloro-xylenes yielded p-, m- and o-xylyl bridged dinuclear complexes of η⁵-Cp^*M(CO)₃ in high yields. All of such new complexes are stable to air and water, even stable in dilute acids and bases.     

An Improved Preparation of Polymer-Type η3-Allylpalladiumchlorides

Five polymer-type new compounds-(η³-cyclopentadienyl)palladiumchloride ( 6 ), (η³-indenyl) palladiumchloride ( 7 ), (η³-cycloheptatrienyl)palladiumchloride ( 8 ), (η³-phenalenyl)palladiumchloride ( 9 ) and (1,2,3-η³-4,5,6,7-η⁴-cyclopheptatrienyl)(palladium-chloride)(tricarboryl Iron) ( 10 ) have been prepared from the reaction of Na₂PdCl₄ with 1-trimethylsilylcyclopentadiene ( 1 ), 1-trimethylsilylindene ( 2 ), 1-trimethylsilyl cycloheptatriene ( 3 ), 1-trimethylsilylphenalene ( 4 ) and 1-trimethylsilylcycloheptatriene tricarbonyl Iron ( 5 ) respectively. All the complexes( 6 )-(10) are obtained in excellent yield using the improved preparation route. Furthermore, a reaction mechanism is proposed.     

Crystal and molecular structure of [(C6H5)2P(=0)(CH2CH2N(CH3)3 +][I−]

The title compound crystallizes in the centrosymmetric triclinic space group withZ=4. The crystallographic asymmetric unit contains two independent cations; interatomic distances within these include P=O=1.47(1) and 1.47(1) Å, P–C₆H₅=1.78(2)–1.81(1)Å and P–CH₂CH₂NMe₃ ⁺=1.80(1) and 1.81(1) Å. The phosphine oxide moiety is involved in intermolecular hydrogen bonding ()...H–C, with O...H2.42Å) and the iodide is involved in I...H–C contacts with I...H3.10Å.     

On asymptotic tests in three-factor factorial designs with no replications

We revisit the problems of testing three-factor classification models with a single observation per cell. A common approach in analyzing such nonreplicated data is to omit the highest order interaction and regard it as error. This paper discusses the use of a multiplicative model (See and Smith, 1996 and 1998) which is applied on residuals in order to separate the variability due to three-factor interaction from what is counted as random error. In particular, to test the significance of the interaction term, we derived an approximated distribution of the likelihood ratio test statistic based on the quadrilinear model known as Tucker’s three-mode principal component model. The derivation utilizes the distribution of the eigenvalues of the Wishart matrix.     

Cancellation of fine-structure splitting in quantum dots by a magnetic field

We demonstrate control of the fine-structure splitting of the exciton emission lines in single InAs quantum dots by the application of an in-plane magnetic field. The composition of the barrier material and the size and symmetry of the quantum dot are found to determine decrease or increase in the linear polarization splitting of the dominant exciton emission lines with increasing magnetic field. This enables the selection of dots for which the splitting can to be tuned to zero, within the resolution of our experiments. General differences in the g-factors and exchange splittings are found for different types of dot.     

Efficient single photon detection by quantum dot resonant tunneling diodes

We demonstrate that the resonant tunnel current through a double-barrier structure is sensitive to the capture of single photoexcited holes by an adjacent layer of quantum dots. This phenomenon could allow the detection of single photons with low dark count rates and high quantum efficiencies. The magnitude of the sensing current may be controlled via the thickness of the tunnel barriers. Larger currents give improved signal to noise and allow sub-mus photon time resolution.     

Optical V(z) for high-resolution 2pi surface plasmon microscopy

Surface plasmons are electromagnetic surface waves whose k vectors are greater than that of free-space radiation. We excite surface plasmons by using an oil-immersion lens, which forms one arm of an interferometer. We demonstrate the way in which the characteristic output variation with defocus is determined by the propagation properties of the surface plasmons, which leads to diffraction-limited surface plasmon microscopy in the far field.     

Modelling of ER squeeze films at low amplitude oscillations

An experimental investigation of electrorheological squeeze film dynamics is presented for constant applied voltage and low strain amplitude. Both broadband random and sinusoidal motion are examined to explain complex film dynamics. Spectral results indicate a primarily elastic response with slip at the plate boundaries. By examining the evolution of an effective shear modulus over time, sinusoidal results show that slip at the boundaries is due to a solvent layer which may be modelled as a separate variable thickness squeeze film.