Influence of calcination temperature on structural and optical properties of TiO2-SiO2 thin films prepared by sol-gel dip coating

We prepared TiO₂-SiO₂ thin films with various TiO₂/SiO₂ ratios by sol-gel dip coating method and explored the dependence of their structural and optical properties on calcination temperature. The absorption peaks relevant to Si—O, Si—O—Ti and Ti—O bonds appeared in the FTIR spectra. With increasing TiO₂ content, the intensity of Si—O bond peaks decreases and that of Ti—O bond peaks increases. The XRD results show that the temperature of transformation from amorphous to anatase phase is lowered as TiO₂ content increases. The crystallite size of anatase phase in composite thin films increases with increasing TiO₂ content and calcination temperature. At 1000°C, the mixed phase of anatase and rutile appears in the pure TiO₂ thin films. The rutile films are denser than the anatase films. The increase in refractive index of composite thin films with calcination temperature is related to the decreased thickness and increased density as a result of evaporation of water and organic matters below 400°C. On the other hand, it is related to the change in the crystal phase and crystallite size of the films over 400°C.     

A nonlinear minimization approach to multiobjective and structured controls for discrete‐time systems

In this paper, a nonlinear minimization approach is proposed for multiobjective and structured controls for discrete‐time systems. The problem of finding multiobjective and structured controls for discrete‐time systems is represented as a quadratic matrix inequality problem. It is shown that the problem is reduced to a nonlinear minimization problem that has a concave objective function and linear matrix inequality constraints. An algorithm for the nonlinear minimization problem is proposed, which is easily implemented with existing semidefinite programming algorithms. The validity of the proposed algorithm is illustrated by comparisons with existing methods. In addition, applications of this work are demonstrated via numerical examples. Copyright © 2004 John Wiley & Sons, Ltd.     

Hinging hyperplane based regression tree identified by fuzzy clustering and its application

Hierarchical fuzzy modeling techniques have great advantage since model accuracy and complexity can be easily controlled thanks to the transparent model structures. A novel tool for regression tree identification is proposed based on the synergistic combination of fuzzy c-regression clustering and the concept of hierarchical modeling. In a special case (c = 2), fuzzy c-regression clustering can be used for identification of hinging hyperplane models. The proposed method recursively identifies a hinging hyperplane model that contains two linear submodels by partitioning operating region of one local linear model resulting a binary regression tree. Novel measures of model performance and complexity are developed to support the analysis and building of the proposed special model structure. Effectiveness of proposed model is demonstrated by benchmark regression datasets. Examples also demonstrate that the proposed model can effectively represent nonlinear dynamical systems. Thanks to the piecewise linear model structure the resulted regression tree can be easily utilized in model predictive control. A detailed application example related to the model predictive control of a water heater demonstrate that the proposed framework can be effectively used in modeling and control of dynamical systems.     

MicroRNA-155 Mediates Augmented CD40 Expression in Bone Marrow Derived Plasmacytoid Dendritic Cells in Symptomatic Lupus-Prone NZB/W F1 Mice

Systemic lupus erythematosus (SLE) is a chronic multi-organ autoimmune disease characterized by hyperactivated immune responses to self-antigens and persistent systemic inflammation. Previously, we reported abnormalities in circulating and bone marrow (BM)-derived plasmacytoid dendritic cells (pDCs) from SLE patients. Here, we aim to seek for potential regulators that mediate functional aberrations of pDCs in SLE. BM-derived pDCs from NZB/W F1 mice before and after the disease onset were compared for toll-like receptor (TLR) induced responses and microRNA profile changes. While pDCs derived from symptomatic mice were phenotypically comparable to pre-symptomatic ones, functionally they exhibited hypersensitivity to TLR7 but not TLR9 stimulation, as represented by the elevated upregulation of CD40, CD86 and MHC class II molecules upon R837 stimulation. Upregulated induction of miR-155 in symptomatic pDCs following TLR7 stimulation was observed. Transfection of miR-155 mimics in pre-symptomatic pDCs induced an augmented expression of Cd40, which is consistent with the increased CD40 expression in symptomatic pDCs. Overall, our results provide evidence for miR-155-mediated regulation in pDC functional abnormalities in SLE. Findings from this study contribute to a better understanding of SLE pathogenesis and ignite future interests in evaluating the molecular regulation in autoimmunity.     

Incremental semantic analysis for OCL compilers

In software engineering, modeling with unified modeling language and object constraint language became industry standards and are supported by many computer-aided software engineering tools. The increasing number of the modeled functionalities results in complex models that need more and more textual constraints to express the hidden restrictions applied to the systems. During the metamodel development, rebuilding all the constraints is unnecessary when only a few changes have been applied due to the iterative, incremental manner of modifications. In this paper, we present a family of algorithms that handles the changes in constraints incrementally on the expression level; thus, the required rebuilds are kept to a minimum. Incremental variable reference resolving and type checking are performed as a part of the incremental semantic analysis. Balancing between the incremental and standard compilation is also considered, heuristics are given to select the faster method of compilation at each iteration. With the achieved results the duration of metamodel development can be decreased; thus, the efficiency of the environment is improved.     

Field measurement and estimation of ventilation flow rates by using train-induced flow rate through subway vent shafts

This study measured and estimated the subway vent shaft air flow rate induced by moving trains in the tunnel. This work estimated the flow rate via the tunnel structure and train movement to determine the quantitative effect of vent shafts as air purification systems of natural ventilation to improve the air quality management of a subway. The amount of air suctioned into the tunnel is significantly larger than that vented from the tunnel. Thus, placing vent shafts near subway stations is desirable for natural ventilation systems. Experimental approaches to measure train-induced flow rates have not yet been published. Results of this study provide useful fundamental data to study the natural ventilation in a subway. Therefore, this study suggested the significant design factors required to control indoor air quality in a subway.     

Proton incorporation in yttria-stabilized zirconia during atomic layer deposition

This work elucidated the proton-incorporation mechanism in ALD YSZ¹. Isotope ²H₂O was used as an oxidant to trace proton incorporation. The ratio of ZrO₂ to Y₂O₃ ALD cycles was varied from 1:1 to 5:1. TEM confirmed that the ALD YSZ films grew as fully crystallized columnar grains in the cubic ZrO₂ phase. SIMS indicated that the Y³⁺ and ²H⁺ concentrations were linearly correlated, indicating yttria-deposition-induced proton incorporation. XPS confirmed an appreciable amount of Y(OH)₃ proportional to the ²H⁺ content in the ALD YSZ, as was also detected by SIMS. Oxide ion vacancies created by the replacement of ZrO₂ with relatively small amounts of Y₂O₃ provided additional vacancies for proton incorporation, resulting in steeper [²H⁺]/[Y³⁺] slopes.     

Carbon nanotube/Co<Subscript>3</Subscript>O<Subscript>4</Subscript> composite for air electrode of lithium-air battery

A carbon nanotube [CNT]/Co₃O₄ composite is introduced as a catalyst for the air electrode of lithium-air [Li/air] batteries. Co₃O₄ nanoparticles are successfully attached to the sidewall of the CNT by a hydrothermal method. A high discharge capacity and a low overvoltage indicate that the CNT/Co₃O₄ composite is a very promising catalyst for the air electrode of Li/air batteries.     

A general simulation procedure for the electrical characteristics of metal-insulator-semiconductor tunnel structures

The algorithm is suggested for calculating the I–V characteristics of a voltage- or current-controlled metal-tunnel-thin insulator-semiconductor system. The basic underlying physical models are discussed. Applicability of the algorithm is confirmed by a comparison of the simulation results with the measurement data obtained by the authors and borrowed from the literature, for several different structures. The presented information is supposed to suffice for calculating the electrical characteristics of the investigated structures with the various combinations of materials: metal or polysilicon gate, single-layer or stacked insulator, and semiconductor with any doping type and level.