Reagenzien zar Identifizierung von Aldehyden und Ketonen.

Ohne Zusammenfassung     

Nanoscale C‐Rich SixC1−x Bus/Ring Waveguide Based Cross‐Wavelength Data Converter

The carbon‐rich silicon carbide (C‐rich Si_xC_1?x) micro‐ring channel waveguide with asymmetric core aspect is demonstrated for all‐optical cross‐wavelength pulsed return‐to‐zero on‐off keying (PRZ‐OOK) data conversion. Enhanced nonlinear optical Kerr switching enables 12‐Gbit per second data processing with optimized modulation depth. The inverse tapered waveguide at end‐face further enlarges the edge‐coupling efficiency, and the asymmetric channel waveguide distinguishes the polarization modes. To prevent data shape distortion, the bus/ring gap spacing is adjusted to control the quality factor (Q‐factor) of the micro‐ring. Designing the waveguide cross section at 500 × 350 nm² provides the C‐rich Si_xC_1?x channel waveguide to induce strong transverse electric mode (TE‐mode) confinement with a large Kerr nonlinearity of 2.44 × 10^?12 cm² W^?1. Owing to the trade‐off between the Q‐factor and the on/off extinction ratio, the optimized bus/ring gap spacing of 1400 nm is selected to provide a coupling ratio at 5–6% for compromising the modulation depth and the switching throughput. Such a C‐rich Si_xC_1?x micro‐ring with asymmetric channel waveguide greatly enhances the cross‐wavelength data conversion efficiency to favor its on‐chip all‐optical data processing applications for future optoelectronic interconnect circuits.     

Structural, electrical, optical and magnetic properties of Co0.2AlxZn0.8−xO films

Co_0.2Al_xZn_0.8−xO films prepared with different molar ratio of aluminum nitrate to zinc acetate were deposited on substrates by the sol-gel technique. X-ray diffraction, photoluminescence and ferromagnetism measurements were used to characterize the Co_0.2Al_xZn_0.8−xO diluted magnetic semiconductors. The authors found that the intensity of the acceptor-related photoluminescence increased with increasing aluminum concentration and an increase in the number of the acceptor-like defects (zinc vacancies especially) in the Co_0.2Al_xZn_0.8−xO film might lead to the enhancement of the magnetic properties. This implies that controls of the aluminum concentration and the number of the acceptor-like defects are important factors to produce strong ferromagnetism Co_0.2Al_xZn_0.8−xO films prepared by the sol-gel method.     

Optical design of bent rib waveguide with MOS cross-section

We provided a single-mode bent MOS-cross-section rib waveguide design with 0.9 dB/cm bending loss at 25 μm bending radius. The peak position for the TE-like mode was tuned to the gate oxide around which the maximum amount of free carriers are accumulated to optimize the free carrier dispersion effect.     

Nanoscale yttrium distribution in yttrium-doped ceria powder

The microstructure and geometry of yttrium-doped ceria particles, synthesized by spray pyrolysis (SP), were characterized by transmission electron microscopy, and the distribution of yttrium was investigated by energy-dispersive X-ray spectroscopy (EDX). The yttrium distribution was investigated by considering an electron interaction volume and geometry of the particle in an EDX profile analysis. Two models, linear and non-linear, for the yttrium concentration gradient were tested against the experimental EDX data for hollow particles. The results showed that the linear concentration distribution of yttrium fits the EDX profiles appreciably better than the non-linear concentration gradient model. This suggests that yttrium distribution is mainly controlled by the different diffusion rates of the precursors from the centre to the surface of the particle, which could be related to their different solubilities, during the heating process in SP.     

Chaos control of new Ikeda–Lorenz systems by GYC partial region stability theory

A new strategy to achieve chaos control by GYC partial region stability theory is proposed. By using the GYC partial region stability theory, the Lyapunov function is a simple linear homogeneous function of error states, the controllers are more simple and have less simulation error because they are in lower degree than that of traditional controllers. Simulation results for a new Ikeda–Lorenz system show the effectiveness of this strategy. Copyright © 2008 John Wiley & Sons, Ltd.     

Tailored Finite Point Method for Numerical Solutions of Singular Perturbed Eigenvalue Problems

We propose two variants of tailored finite point (TFP) methods for discretizing two dimensional singular perturbed eigenvalue (SPE) problems. A continuation method and an iterative method are exploited for solving discretized systems of equations to obtain the eigen-pairs of the SPE. We study the analytical solutions of two special cases of the SPE, and provide an asymptotic analysis for the solutions. The theoretical results are verified in the numerical experiments. The numerical results demonstrate that the proposed schemes effectively resolve the delta function like of the eigenfunctions on relatively coarse grid.     

Bacterial pyomyositis: MRI and clinical correlation

OBJECTIVE: To characterize the findings of magnetic resonance imaging (MRI) of bacterial pyomyositis (PM) and correlate these data with the clinical information. MATERIALS AND METHODS: Eighty-one patients were diagnosed with PM in our institute between 1997 and 2003. Of these, 40 patients (21 male, 19 female; mean age, 53 years) also underwent MRI examination. The clinical manifestation underlying medical problems and the characteristics of MRI were analyzed. Thirty of the patients received surgical intervention or image-guided drainage/aspiration of the abscess along with administration of antibiotics, while the remaining 10 patients were promptly treated solely with antibiotics. RESULTS: Thirty-one of 40 patients had underlying medical problems. These involved diabetes mellitus (DM, n = 16), malignancies including cervical cancer, prostate cancer, non-Hodgkin's lymphoma and acute lymphocytic leukemia (n = 10, one case also had DM), autoimmune disease or asthma with long-term steroid usage (n = 4, one case also had DM), liver cirrhosis (n = 2) and chronic renal insufficiency (n = 1). Four patients had no abscess formation at presentation (invasive or early purulent stage), while the remaining 36 cases presented with at least one abscess (purulent stage). Patients older than 40 years or DM patients tended to have larger abscess(s) (P < .05). Gadolinium-enhanced images demonstrated either thick (n = 12) or thin rim enhancement (n = 24) of the abscess wall. For those 10 patients promptly treated solely with antibiotics, nine demonstrated thin rim enhancement of the abscess (P < .05). CONCLUSION: Magnetic resonance imaging plays an important role in the early recognition of bacterial PM. By precisely demarcating the extent of the disease, MRI can allow planning prompt antibiotic treatment combined with or without interventional procedures.     

The regioselective switch for amino-NHC mediated C-H activation of benzimidazole via Ni-Al synergistic catalysis

We have disclosed a new mode of a chemically regioselective switch for C-H bond functionalization of benzimidazole derivatives via a cooperative effect invoked by Ni-Al bimetallic catalysis to create a steric requirement for obtaining the linear product of styrene insertion. Yet, excluding the AlMe(3) cocatalyst switches the reaction toward branch selectivity.