Control of nano/microstructure and pit initiation sites on aluminium surface by use of self‐assembled spheres

Nano/microstructure control and electrochemical etching of aluminium substrate using a honeycomb alumina mask fabricated by anodisation with self‐assembled spheres aligned on the aluminium surface were studied to directly control the initiation sites of pits. The transfer of the hexagonally ordered pattern of self‐assembled spheres to the aluminium substrate could be achieved by substantially suppressed anodic oxide growth under the spheres where selective electrochemical etching proceeded. That is, etch pits are generated only in the thinner areas or holes of the honeycomb alumina mask with a one‐to‐one correspondence. With this process, improvements in pit distribution density and the homogeneity of pit sizes, while avoiding excessive dissolution of the aluminium surface, could be achieved easily in comparison with the conventional method. The density of pits could also be controlled by changing the diameter of spheres used as an indirect mask. Copyright © 2010 John Wiley & Sons, Ltd.     

EVAPORATION CHARACTERISTICS OF Se/Te ALLOYS AS APPLIED TO PHOTORECEPTORS

Abstract

Xerographic devices obtained by vacuum deposition of SeTe alloys have inhomogeneities in stoichiometry because of the differences in vapor pressures of the individual elements. As a result the concentration of Te on the top surface of the devices is considerably higher than the rest of the film. This is termed as “fractionation”. It has been observed that the fractionation characteristics of the SeTe alloys are dependent on the quenching temperature during the alloy preparation which in turn affects the electrical properties of the photoreceptors.     

Two polymorphs of N1,N4‐bis(5‐hydroxypenta‐1,3‐diynyl)‐N1,N4‐diphenylbenzene‐1,4‐diamine

The title compound, C₂₈H₂₀N₂O₂, forms two conformational polymorphs, (I) and (II), where the molecular structures are similar except for the orientation of the two hydroxy groups. In (I), which was obtained by slow evaporation from chloroform, the two hydroxy groups have an anti conformation. The molecules form a sheet structure within the ac plane, where the hydroxy groups form zigzag hydrogen bonds. In (II), which was obtained by slow evaporation from acetonitrile, the two hydroxy groups have a syn conformation. The molecules form a double‐sheet structure within the ab plane, where the hydroxy groups form 4‐helix hydrogen bonds.     

A five‐coordinate ruthenium(II)–porphyrin–carbene complex: [bis(3‐trifluoromethylphenyl)methylene‐κC](5,10,15,20‐tetra‐p‐tolylporphyrinato‐κ4N)ruthenium(II)

The stable title tri­fluoro­methyl‐substituted carbenyl metalloporphyrin, [Ru(C₁₅H₈F₆)(C₄₈H₃₆N₄)], has a five‐coordinate Ru atom which is displaced from the porphyrin N₄ plane towards the axial carbene ligand by 0.230 (3) Å. The Ru—C(carbene) bond coincides with a crystallographic twofold axis and its length of 1.841 (6) Å is notably shorter than the value of 1.868 (3) Å in the pyridine adduct.     

Postgel properties in the statistical crosslinking of heterochains. I. Systems with N types of chains

The heterochain crosslinking model describes nonrandom crosslinking of polymer chains and is an extension of the classical Flory/Stockmayer gelation theory. We consider the postgelation relationship for the system consisting of N types of polymer chains, in which the probability that a crosslink point on an i‐type chain is connected to a j‐type chain is explicitly given by p_ij. The analytical solutions for the weight fraction of the sol, the number‐average and weight‐average molecular weights within the sol fraction, and the crosslinking density within the sol and gel fractions are derived for the systems, with each type of chain conforming to the Schulz–Zimm distribution. Illustrative calculations are shown for the systems consisting of two and three types of chains, and the obtained results agree with those from the Monte Carlo method. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 2333–2341, 2000     

Sharp Growth Theorems and Coefficient Bounds for Starlike Mappings in Several Complex Variables

Let B be the unit ball in a complex Banach space. Let S^＊k＋1（B） be the family of normalized starlike mappings f on B such that z = 0 is a zero of order k ＋ 1 of f（z） - z. The authors obtain sharp growth and covering theorems, as well as sharp coefficient bounds for various subsets of S^＊k＋1（B）.     

Hybrid quantum circuit with a superconducting qubit coupled to a spin ensemble

We report the experimental realization of a hybrid quantum circuit combining a superconducting qubit and an ensemble of electronic spins. The qubit, of the transmon type, is coherently coupled to the spin ensemble consisting of nitrogen-vacancy centers in a diamond crystal via a frequency-tunable superconducting resonator acting as a quantum bus. Using this circuit, we prepare a superposition of the qubit states that we store into collective excitations of the spin ensemble and retrieve back into the qubit later on. These results constitute a proof of concept of spin-ensemble based quantum memory for superconducting qubits.