Order to disorder optical phase transition in random photonic crystals

Transition process of optical modal properties induced by the introduction of randomness into random photonic crystals is investigated by a computational method. We analyze an impulse response of two-dimensional triangular photonic crystals, in which the positions of the air holes are slightly deviated to random directions. It is shown that the appropriate degree of random departure from a perfect crystal state gives rise to multiple scattering of low group velocity band-edge modes and supports their strong Anderson localization. The achieved confinement efficiency of light exceeds the one obtained in the perfect photonic crystal state.     

Evolution of two-step structural phase transition in Fe1+dTe detected by low-temperature x-ray diffraction

The low-temperature crystal structure of Fe_1.13Te, which exhibits an anomalous two-step magnetic transition, was clarified by the systematic x-ray diffraction measurements. It was found that two-step structural phase transition, tetragonal–orthorhombic–monoclinic, occurred correspondingly to the two-step magnetic transition. The detailed analysis of the profile at 5 K indicated the coexistence of the minor orthorhombic area inside the major, monoclinic lattice, which could explain the lower-shift (suppression) of the antiferromagnetic transition temperature in Fe_1.13Te and suggest a possibility of superconductivity at the domain boundary.     

Solutions for the generalized Loewner differential equation in several complex variables

We generalize a one-variable result of J. Becker to several complex variables. We determine the form of arbitrary solutions of the Loewner differential equation that is satisfied by univalent subordination chains of the form ${f(z, t)=e^{tA}z+\cdots,}We generalize a one-variable result of J. Becker to several complex variables. We determine the form of arbitrary solutions of the Loewner differential equation that is satisfied by univalent subordination chains of the form f(z, t)=e^tAz+?,{f(z, t)=e^{tA}z+\cdots,} where A ? L(\mathbbCⁿ, \mathbbCⁿ){A\in L(\mathbb{C}^n, \mathbb{C}^n)} has the property k ₊(A) < 2m(A). Here k₊(A)=max{?l:l ? s(A)}{k_+(A)=\max\{\Re\lambda:\lambda\in \sigma(A)\}} and m(A)=min{?áA(z), z ?: ||z||=1}{m(A)=\min\{\Re\langle A(z), z \rangle: \|z\|=1\}} . (The notion of parametric representation has a useful generalization under these conditions, so that one has a canonical solution of the Loewner differential equation.) In particular, we determine the form of the univalent solutions. The results are applied to subordination chains generated by spirallike mappings on the unit ball in \mathbbCⁿ{\mathbb{C}^n} . Finally, we determine the form of the solutions in the presence of certain coefficient bounds.     

Aqueous synthesis of single-crystalline ZnO prisms on graphite substrates

Morphological change from ZnO films to ZnO prisms is achieved by an electrochemical deposition method on a graphite substrate at the low temperature of 70 °C. The ZnO prisms, which are prism-shaped ZnO rods with a wide diameter, have hexagonal well-defined crystallographic facets. The ZnO prism is 1.4 μm in diameter and 1.3 μm in length. Transmission electron microscopy and electron diffraction patterns indicate that the ZnO prisms have a single-crystalline wurtzite structure with c-axis orientation. Additionally, cathodoluminescence shows that the annealed ZnO prisms in nitrogen gas emit a significant level of near-band-edge ultraviolet light.     

A novel synthesis of α,β-unsaturated nitriles from aromatic ketones via cyanophosphates

Reaction of aromatic ketones with diethyl phosphorocyanidate in the presence of lithium cyanide gave cyanophosphates, which were converted into α,β-unsaturated nitriles by treatment with boron trifluoride etherate in high yields.     

Electronic origin of the surface reconstruction and relaxation of the (001) surface of Mo and W

The reconstruction and the relaxation of the (001) surface of Mo and W are studied by using the tight-binding d band and the Born-Mayer repulsive potential. The d band parameters are set to reproduce band energies of ab initio band calculations at high symmetry points in the Brillouin zone and the parameters in the Born-Mayer potential are chosen to obtain the correct equilibrium lattice constant and the bulk modulus of the bulk crystal. First, we give a detailed discussion on the mechanism of the surface relaxation, and then show that the (001) surfaces of Mo and W are unstable to the c(2 × 2) mode but stable with regard to the (2 × 1) mode. By calculating the energy change up to the fourth order of atomic displacement, we determine the stable surface atomic structure which is in fair agreement with experiments.     

Electron cyclotron heating in high density toroidal plasmas

Wave trajectories of the ordinary mode as well as the extraordinary one injected obliquely into a magnetic field in high density toroidal plasmas, are studied theoretically. Both waves are finally converted into the electron Bernstein mode and cyclotron damped.     

Dynamic light scattering of polystyrene single chains in a semidilute solution of poly(methyl methacrylate) and benzene

Translational diffusion and internal motion have been observed by dynamic light scattering of optically labeled single chains of polystyrene (PS) in a semidilute solution of poly(methyl methacrylate) and benzene for the case in which the dimension R_g of the PS chain is comparable to the correlation length of the matrix solution. The molecular weight M_w dependence of the hydrodynamic radius R_h is expressed as R_h ～ M, while R_h ～ M in pure benzene. The average linewidth Γ for internal motions (KR_g > 1) appears to depend on the magnitude K of the scattering vector approximately as Γ ∝ K⁴ at higher KR_g ( > 1), in contrast with the fact that Γ ∝ K³ approximately for KR_g > 1 in pure benzene. The scaling law for the K dependence of Γ does not hold in low-molecular-weight PS owing to the K dependence of Γ /K² for KR_g < 1.     

Anion-exchange separation of rhodium and iridium by ECTEOLA-cellulose column

Summary The separation of Rh(III) and Ir(IV) in amounts of 20–5300 and 20–7700 g, respectively, and in ratios of RhIr=1100 to 1001 was achieved without cross-contamination by use of a 3 g ECTEOLA-cellulose column. Rh was first eluted with 40 ml of a 3 mol/l HCl-1% (w/v) NaClO₃ solution. Ir(IV) was desorbed with 60 ml of a 6 mol/l HCl-0.1% (w/v) NaClO₃ solution. Quantitative recoveries were obtained for each metal. The present method provides much better resolution than the other existing anion-exchange methods and can effectively be applied to the separations and recoveries of Rh and Ir(III or IV) present in a more extensive range of amounts and ratios.

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Anionenaustausch-Trennung von Rhodium und Iridium mit Hilfe einer ECTEOLA-Cellulose-Säule