Solution of the Schrödinger equation for two different molecular potentials by the Nikiforov-Uvarov method

In this study, the solution of the Schr?dinger equation by a method developed by Nikiforov and Uvarov which is not based on the manipulation of formal power series has been schematically presented. The method gives elegant, easy and exact solutions of the Schr?dinger equation. In order to demonstrate the applications of the method, solutions of the Schr?dinger equation for the well-known pseudo-harmonic oscillator and a new symmetrical potential proposed by the authors are given. The concrete energy spectra and corresponding wave functions are obtained. The superiority and the limitations of the method compared to other methods have also been emphasized. Received: 20 November 1996 / Accepted: 1 October 1997     

Mechanism and kinetics of ordering in diblock copolymer thin films on chemically nanopatterned substrates

Lamellae forming diblock copolymer domains can be directed to assemble without defects and in registration with chemically nanopatterned substrates. Initially, thin films of the lamellar poly(styrene-b-methyl methacrylate) block copolymer form hexagonally close-packed styrene domains when annealed on chemical nanopatterned striped surfaces. These styrene domains then coalesce to form linear styrene domains that are not fully registered with the underlying chemical surface pattern. Defects coarsen, until defect-free directed assembly is obtained, by breaking linear styrene domains and reforming new structures until registered lamellae have been formed. At all stages in the process, two factors play an important role in the observed degree of registration of the block copolymer domains as a function of annealing time: the interfacial energy between the blocks of the copolymer and the chemically nanopatterned substrate and the commensurability of the bulk repeat period of the block copolymer and the substrate pattern period. Insight into the time-dependent three-dimensional behavior of the block copolymer structures is gained from single chain in mean field simulations. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 3444–3459, 2005     

Direct imaging of surface topology and pore system of ordered mesoporous silica (MCM-41, SBA-15, and KIT-6) and nanocast metal oxides by high resolution scanning electron microscopy

We report here a detailed study on the surface topology of well-known ordered mesoporous silica (SBA-15, MCM-41, and KIT-6) and a series of nanocast Co 3O 4, Co 3O 4/CoFe 2O 4 composites by high resolution scanning electron microscopy (HR-SEM). Images of the MCM-41 structure were obtained at a resolution of the pore size, as well as a real space image of the gyroid silica surface of KIT-6 for two different aging temperatures, clearly revealing the differences of the aging procedures. By using the low voltage HR-SEM technique with extremely high resolution, we could very clearly show the influence of the template properties on the structure of the nanocast metal oxides.     

Pseudomorphic transformation of highly ordered mesoporous Co3O4 to CoO via reduction with glycerol

In this report, we describe the exploration of possibilities for a pseudomorphic reduction of ordered mesoporous metal oxides by high temperature treatment with glycerol, which was most thoroughly studied as an example of the reaction of Co3O4 to CoO. It was found that the glycerol process is a gentle reduction procedure, which maintains the framework topology on the mesoscale while changing the oxidation state and the structure at the atomic scale.     

Microstructured proton-conducting membranes by synchrotron-radiation-induced grafting

Selective exposures of poly(ethylene-alt-tetrafluoroethylene) (ETFE) films with hard X-rays through high aspect ratio Ni-masks were performed at the LIGA3 beamline of the “Angström Quelle Karlsruhe” (ANKA) to create patterns of radicals used as initiators for the grafting of styrene into the bulk of the ETFE films. Grafted films were then sulfonated to obtain proton-conducting membranes. The structure definition, as investigated by scanning electron microscopy (SEM), showed a perfect discrimination between exposed and shaded areas through all the film thickness. Structuring results in a more homogeneous appearance of the membrane without affecting the degree of grafting and proton conductivity in the grafted areas. In fuel cell tests the structured membranes showed slightly lower performance due to 10% lower active area, but had a significantly higher lifetime.     

Titanium Carbide MXene as a Mode Locker in Erbium-Doped Fiber Laser Cavity

Journal of Russian Laser Research - We propose a MXene Ti3C2Tx thin-film and demonstrate as saturable absorber (SA) to generate mode-locked laser pulses. In constructing the SA, titanium carbide...     

Gain-flattened S-band depressed cladding erbium doped fiber amplifier with a flat bandwidth of 12 nm using a Tunable Mach-Zehnder Filter

S-band amplification is an important area of optical communications research, focusing on meeting the ever-increasing demands for traffic bandwidth as the C- and L-bands approaches to their limits. In this paper a novel method of providing an S-band optical amplifier with a flat gain-bandwidth is proposed. The proposed method utilizes a Depressed Cladding Erbium Doped Fibre together with a Tunable Mach-Zehnder Filter as to generate a flat amplification bandwidth of 12 nm stretching from 1492 to 1504 nm. The average gain value is approximately 24.21 dB, with a peak to peak fluctuation of 0.83 dB and a noise figure ranges from 7.13 to 10.94 dB for input signals of 1484 to 1510 nm.     

A Supported Bismuth Halide Perovskite Photocatalyst for Selective Aliphatic and Aromatic C–H Bond Activation

Direct selective oxidation of hydrocarbons to oxygenates by O₂ is challenging. Catalysts are limited by the low activity and narrow application scope, and the main focus is on active C?H bonds at benzylic positions. In this work, stable, lead‐free, Cs₃Bi₂Br₉ halide perovskites are integrated within the pore channels of mesoporous SBA‐15 silica and demonstrate their photocatalytic potentials for C?H bond activation. The composite photocatalysts can effectively oxidize hydrocarbons (C₅ to C₁₆ including aromatic and aliphatic alkanes) with a conversion rate up to 32900 μmol g_cat^?1 h^?1 and excellent selectivity (>99 %) towards aldehydes and ketones under visible‐light irradiation. Isotopic labeling, in situ spectroscopic studies, and DFT calculations reveal that well‐dispersed small perovskite nanoparticles (2–5 nm) possess enhanced electron–hole separation and a close contact with hydrocarbons that facilitates C(sp³)?H bond activation by photoinduced charges.     

Transmission characteristic of multi-turn microfiber coil resonator

A transmission characteristic of multi-turn microfiber coil resonator (MCR), which is assembled from an adiabatic microfiber, is demonstrated. A comb spectrum was obtained by wrapping a microfiber on a low refractive indexed rod. A resonance with a free spectral range of 0.8 nm was observed with a single turn on a 0.5 mm diameter low-indexed rod and the change in transmission spectrum of the MCR was evident as the number of turns increased. For every additional microfiber turn, there was an addition of an eigenmode to the system which could be observed from the addition of a new resonance for every fringe in the transmission spectrum. The FSR for every added eigenmode was measured to be close to 0.8 nm.