bluuebunny/crossref_metadata_2025 huggingface dataset:
HIGH PERFORMANCE, LOW-COMPLEXITY LINE-BASED MOTION ESTIMATION ALGORITHM WITH SMOOTHING AND PREPROCESSING
Authors: CHEW LI WERN , CHIA WAI CHONG , ANG LI-MINN , SENG KAH PHOOI
Published: March 2009

This paper introduces a smoothing and preprocessing (S+P) technique for a line-based one-bit-transform (1BT) motion estimation scheme. In the proposed algorithm, a smoothing threshold ( Threshold S) is incorporated into the 1BT convolutional kernel. By using the smoothing threshold, scattering noise which is a common problem in most 1BT images can be greatly reduced. After the transformation, the 1BT images for the current and reference frames are divided into a number of macroblocks. The macroblock in the current frame is first compared with the macroblock at the same position in the reference frame. If the Sum of Absolute Difference (SAD) is below a certain preprocessing threshold ( Threshold P), the macroblock in the current frame is considered to have negligible movement and motion search is not performed. Simulation results show that this technique achieves high performance and greatly reduces the number of search operations. By incorporating the S+P technique, the PSNR achieved by the 1BT is approaches the performance of the 8-bit Full Search Block Matching Algorithm (FSBMA), and the difference is as low as 0.08 dB. In addition, this technique outperforms current state-of-the-art 1BT motion estimation techniques. An improvement in PSNR performance by up to 0.6 dB and a reduction in the number of search operations by 60% to 93% is achieved using video conferencing sequences.
A ROBUST IRIS LOCALIZATION ALGORITHM VIA RADIAL SYMMETRY FOR NONIDEAL CAPTURING CONDITION
Authors: ZHANG WEN-CONG , LI BIN , YE XUE-YI , ZHUANG ZHEN-QUAN , WANG KONG-QIAO
Published: March 2009

Iris localization is a key component of practical iris recognition system. Previous algorithms show good localization performances for iris images captured in the ideal conditions. However, in practice, the quality of iris image is greatly influenced by luminance, eyelashes, hair or glasses frame, which will cause mislocalization. In order to improve the robustness of iris localization, this paper proposes a new localization algorithm based on the radial symmetry transform, in which the radial symmetry characteristic of the pupil is utilized to realize iris localization. Experimental results show that the proposed algorithm can efficiently avoid the interference of luminance and other bad conditions, and realize robust precise localization in a real-time system.
HIGH PERFORMANCE SCALABLE RADIX-2n GF(2m) SERIAL–SERIAL MULTIPLIERS
Authors: ALMILADI ABDURAZZAG , IBRAHIM MOHAMAD
Published: March 2009

In this paper, a new architecture for radix-2n serial–serial multiplication/reduction for the finite field GF(2m) is presented. The input operands are serially entered one digit at a time and the output result is computed serially one digit at a time. The reduction polynomial is also fed serially to the structure so that changing the reduction polynomial will not require rewriting or rewiring the structure. The structure utilizes a serial transfer which reduces the bus width needed to transfer data back and forth between memory and multiplication unit. The structure possesses features of regularity, modularity and scalability which are a design requirement for an efficient utilization of FPGA resources. Also, a systolic scalable area efficient design which provides a 50% reduction in hardware without degrading the speed performance is proposed. A radix-4 version of the proposed architecture has been designed, simulated and synthesized using Xilinx ISE 10.1 targeting a Xilinx Virtex-5 FPGA.
ALL GROUNDED PASSIVE ELEMENTS CURRENT-MODE ALL-PASS FILTER
Authors: MINAEI SHAHRAM , YUCE ERKAN
Published: March 2009

In this paper, a new current-mode (CM) all-pass filter employing two Dual-Output Second-Generation Current Conveyors (DO–CCIIs), one grounded resistor and one grounded capacitor is presented. The proposed circuit exhibits low input impedance and high output impedance, which makes it suitable for cascading. Moreover, adding two extra resistors to the proposed circuit, a new gain-variable voltage-mode (VM) all-pass filter is obtained. A quadrature oscillator employing minimum number of grounded passive components is derived from the developed CM filter as an application of the first-order all-pass filter. Both of the proposed all-pass filters do not require matching of passive components. The effects of the parasitic impedances of the DO–CCIIs on the transfer function (TF) of the proposed CM filter as an example are investigated. In addition, the proposed CM all-pass filter and oscillator circuit are simulated using SPICE simulation program to confirm the theory.
IMPROVED REPRESENTATIVES FOR JUDGING UNREPAIRABILITY AND DECIDING ECONOMIC REPAIR SOLUTIONS OF MEMORIES
Authors: LIANG HSING-CHUNG
Published: March 2009

This paper introduces a novel method of identifying better representatives of faulty cells in a memory map to help judge unrepairability and provide economical repair solutions. These representatives, called leading elements (LE), are classified into four primary types based on their characteristics. The proposed method primarily assigns the faulty cells without row or column complements as LE, making them more useful in judging unrepairability and providing economical repair solutions. Some initially identified LE are further replaced with suitable faulty cells for being LE. Experiments on many example maps show the distribution of LE in various sizes of memories with distinct numbers of faulty cells. Compared to the previous work, the improved procedure can identify 7.3% more LE, with only 1.5% additional run time.
AN APPLICATION OF COMPLEX WAVELETS FOR HIGH FREQUENCY SWITCHING NOISE DETECTION
Authors: CHEN WENJIE , YANG XU , WANG ZHAOAN
Published: March 2009

Switching signal is always composed of a series of fast voltage and current transient impulsive waves, which are created during turn-on and turn-off operation of the switching elements. This paper presents a scalogram and phase spectrum analyzing approach for the high-frequency switching noise detection. A complex Gaussian wavelet is used to extract the oscillation feature of the noise signal. The proposed scheme is more suitable in discriminating the type of switching noise than conventional wavelet transform approaches. Simulation results show the effectiveness and advantages of the method.
ALGORITHM FOR AMPLITUDE CONTROL OF LIMIT CYCLES EMERGING FROM HOPF BIFURCATIONS IN 3D SYSTEMS
Authors: LIU SUHUA , TANG JIASHI
Published: March 2009

A general algorithm is proposed for controlling the amplitude of limit cycle emerging from the Hopf bifurcation in a 3D nonlinear dynamic system using nonlinear state feedback. An expression of the curvature coefficient of limit cycle and an explicit control formula are derived by utilizing the center manifold theory and normal form reduction. The expression and formula present a convenient approach to obtain an effective analytical control and predict the amplitude of limit cycles. Three examples — the Langford, the Chen and the Chua systems — are used to illustrate the application of this control approach. The simulation results are presented to confirm the analytical predictions.
BASINS OF ATTRACTION IN NONSMOOTH MODELS OF GEAR RATTLE
Authors: MASON JOANNA F. , PIIROINEN PETRI T. , WILSON R. EDDIE , HOMER MARTIN E.
Published: March 2009

This paper is concerned with the computation of the basins of attraction of a simple one degree-of-freedom backlash oscillator using cell-to-cell mapping techniques. This analysis is motivated by the modeling of order vibration in geared systems. We consider both a piecewise-linear stiffness model and a simpler infinite stiffness impacting limit. The basins reveal rich and delicate dynamics, and we analyze some of the transitions in the system's behavior in terms of smooth and discontinuity-induced bifurcations. The stretching and folding of phase space are illustrated via computations of the grazing curve, and its preimages, and manifold computations of basin boundaries using DsTool (Dynamical Systems Toolkit).
NONLINEAR RESPONSES OF A STRING-BEAM COUPLED SYSTEM WITH FOUR-DEGREES-OF-FREEDOM AND MULTIPLE PARAMETRIC EXCITATIONS
Authors: CAO D. X. , ZHANG W.
Published: March 2009

The nonlinear dynamic responses of a string-beam coupled system subjected to harmonic external and parametric excitations are studied in this work in the case of 1:2 internal resonance between the modes of the beam and string. First, the nonlinear governing equations of motion for the string-beam coupled system are established. Then, the Galerkin's method is used to simplify the nonlinear governing equations to a set of ordinary differential equations with four-degrees-of-freedom. Utilizing the method of multiple scales, the eight-dimensional averaged equation is obtained. The case of 1:2 internal resonance between the modes of the beam and string — principal parametric resonance-1/2 subharmonic resonance for the beam and primary resonance for the string — is considered. Finally, nonlinear dynamic characteristics of the string-beam coupled system are studied through a numerical method based on the averaged equation. The phase portrait, Poincare map and power spectrum are plotted to demonstrate that the periodic and chaotic motions exist in the string-beam coupled system under certain conditions.
GLOBAL EXPONENTIAL STABILITY OF IMPULSIVE FUZZY CELLULAR NEURAL NETWORKS WITH DELAYS AND DIFFUSION
Authors: LI KELIN
Published: March 2009

In this paper, a class of impulsive fuzzy cellular neural networks (FCNNs) with mixed delays and diffusion is formulated and investigated. By establishing an intergro-differential inequality, applying M-matrix theory and inequality technique, several sufficient conditions are obtained to ensure the existence, uniqueness and global exponential stability of an equilibrium point for impulsive FCNNs with mixed delays and diffusion. In particular, the estimate of the exponential convergence rate is also provided, which depends on the system parameters and impulses. These results generalize and improve the earlier publications. Some examples are given to show the effectiveness of the obtained results. It is believed that these results are significant and useful for the design and applications of FCNNs.
FROM THE BOX-WITHIN-A-BOX BIFURCATION ORGANIZATION TO THE JULIA SET PART I: REVISITED PROPERTIES OF THE SETS GENERATED BY A QUADRATIC COMPLEX MAP WITH A REAL PARAMETER
Authors: MIRA CHRISTIAN , GARDINI LAURA
Published: March 2009

Properties of the different configurations of Julia sets J, generated by the complex map TZ: z′ = z2 - c, are revisited when c is a real parameter, -1/4 < c < 2. This is done from a detailed knowledge of the fractal bifurcation organization "box-within-a-box", related to the real Myrberg's map T: x′ = x2 - λ, first described in 1975. Part I of this paper constitutes a first step, leading to Part II dealing with an embedding of TZ into the two-dimensional noninvertible map [Formula: see text]. For γ = 0, [Formula: see text] is semiconjugate to TZ in the invariant half-plane (y ≤ 0). With a given value of c, and with γ decreasing, the identification of the global bifurcations sequence when γ → 0, permits to explain a route toward the Julia sets. With respect to other papers published on the basic Julia and Fatou sets, Part I consists in the identification of J singularities (the unstable cycles and their limit sets) with their localization on J. This identification is made from the symbolism associated with the "box-within-a-box" organization, symbolism associated with the unstable cycles of J for a given c-value. In this framework, Part I gives the structural properties of the Julia set of TZ, which are useful to understand some bifurcation sequences in the more general case considered in Part II. Different types of Julia sets are identified.
ON CHAOTIC BEHAVIOR OF A FIXED OFFSHORE STRUCTURE
Authors: CASSIANO JEFERSON , BALTHAZAR JOSÉ MANOEL
Published: March 2009

In this paper we analyze the qualitative behavior of a fixed offshore oil platform under sea action perturbation (flows and tides), which is modeled by an inverted rigid pendulum with an elastic articulation at sea surface. We study their bifurcation properties provided by analytical framework and investigate their response to small oscillations, considered a more realistic case taking into consideration the platform features as flexibility and saturation.

Our goal is to establish analytic conditions for chaotic oscillations occurrence in this model using the Poincaré–Mel'nikov's criterion for separatrix splitting in transverse orbits, considering external periodic force.
EFFECT OF JUMP DISCONTINUITY FOR PHASE-RANDOMIZED SURROGATE DATA TESTING
Authors: MAMMEN ENNO , NANDI SWAGATA , MAIWALD THOMAS , TIMMER JENS
Published: March 2009

In this paper we discuss two modifications of the surrogate data method based on phase randomization, see [Theiler et al., 1992]. By construction, phase randomized surrogates are circular stationary. In this respect they differ from the original time series. This can cause level inaccuracies of surrogate data tests. We will illustrate this. These inaccuracies are caused by end to end mismatches of the original time series. In this paper we will discuss two approaches to remedy this problem: resampling from subsequences without end to end mismatches and data tapering. Both methods can be understood as attempts to make non-circular data approximately circular. We will show that the first method works quite well for a large range of applications whereas data tapering leads only to improvements in some examples but can be very unstable otherwise.
MACRO- AND MICROSCOPIC APPROACHES TO PLANE STRAIN DEFORMATION STATES OF FACE-CENTERED CUBIC METALS UNDER WEDGE INDENTATION
Authors: GAN YONG X. , CHEN XI
Published: March 2009

Face-centered cubic (FCC) metals show active slip under indentation loading. In this work, both macro- and microscopic models are proposed to analyze the deformation behavior of face-centered-cubic (FCC) single crystals under wedge indentation. In the part of macroscopic approach, stress distribution and anisotropic yielding were investigated. Load-displacement relation was obtained to reveal the mechanical responses of the crystals. In the microscopic approach section, an indention induced lattice rotation zone was identified and the deformation behavior was analyzed using the single crystal plasticity theory. The crystal lattice rotation experimental results and slip line trace observations validate the analytical predictions.
STRAINED FERROELECTRIC THIN FILMS
Authors: ZHANG TONG-YI
Published: March 2009

Using thermodynamics approach, the present work analytically studies the effect of mismatch strains on the material properties of ferroelectric thin films. A one-dimensional model is first developed to illustrate the physical picture and the procedure of the theoretical approach. Then, the effect of non-equal mismatch strains is investigated by using the same theoretical approach.
FORMATION OF CRACK-LIKE DIFFUSION WEDGES AND COMPRESSIVE STRESS EVOLUTION DURING THIN FILM GROWTH WITH INHOMOGENEOUS GRAIN BOUNDARY DIFFUSIVITY
Authors: BHANDAKKAR TANMAY K. , CHASON ERIC , GAO HUAJIAN
Published: March 2009

We consider the effects of inhomogeneous grain boundary (GB) diffusivity on the formation of crack-like grain boundary diffusion wedges and evolution of compressive stress during the growth of a polycrystalline thin film on a substrate with a perfectly bonded film-substrate interface. The problem is formulated as a class of moving boundary diffusion problems with fully coupled elasticity, GB diffusion and film growth. The inhomogeneous GB mobility leads to a set of hypersingular integro-differential equations which are solved by a special numerical scheme. During the film growth, atoms diffuse into the GBs due to the tensile coalescence stress in the film associated with GB formation. We show that, at deposition rates comparable to the diffusion time scale, such GB diffusion leads to temporal decay of GB traction and induces crack-like singular stress concentration at the roots of the GBs. For a slowly growing high mobility thin film, the stress intensity factor near the tip of the diffusion wedge is comparable to that of a GB diffusion wedge under annealing conditions and can lead to nucleation of dislocations, which in turn can influence stress evolution during film growth. Furthermore, the higher chemical potential at the film surface can overdrive adatoms into GBs and result in a final compressive stress in the film. Our simulations on cyclic film deposition and growth interruption processes qualitatively reproduced the experimentally observed behavior of GB mobility on the Stress-Thickness evolution during deposition, the stress relaxation during growth interruption, as well as the dependence of steady state stress on the deposition rate.
SIMULATING THE FLUID DYNAMICS OF NATURAL AND PROSTHETIC HEART VALVES USING THE IMMERSED BOUNDARY METHOD
Authors: GRIFFITH BOYCE E. , LUO XIAOYU , McQUEEN DAVID M. , PESKIN CHARLES S.
Published: March 2009

The immersed boundary method is both a general mathematical framework and a particular numerical approach to problems of fluid-structure interaction. In the present work, we describe the application of the immersed boundary method to the simulation of the fluid dynamics of heart valves, including a model of a natural aortic valve and a model of a chorded prosthetic mitral valve. Each valve is mounted in a semi-rigid flow chamber. In the case of the mitral valve, the flow chamber is a circular pipe, and in the case of the aortic valve, the flow chamber is a model of the aortic root. The model valves and flow chambers are immersed in a viscous incompressible fluid, and realistic fluid boundary conditions are prescribed at the upstream and downstream ends of the chambers. To connect the immersed boundary models to the boundaries of the fluid domain, we introduce a novel modification of the standard immersed boundary scheme. In particular, near the outer boundaries of the fluid domain, we modify the construction of the regularized delta function which mediates fluid-structure coupling in the immersed boundary method, whereas in the interior of the fluid domain, we employ a standard four-point delta function which is frequently used with the immersed boundary method. The standard delta function is used wherever possible, and the modified delta function continuously transitions to the standard delta function away from the outer boundaries of the fluid domain. Three-dimensional computational results are presented to demonstrate the capabilities of our immersed boundary approach to simulating the fluid dynamics of heart valves.
Microglial Physiology: Unique Stimuli, Specialized Responses
Authors: Ransohoff Richard M. , Perry V. Hugh
Published: March 2009

Microglia, the macrophages of the central nervous system parenchyma, have in the normal healthy brain a distinct phenotype induced by molecules expressed on or secreted by adjacent neurons and astrocytes, and this phenotype is maintained in part by virtue of the blood-brain barrier's exclusion of serum components. Microglia are continually active, their processes palpating and surveying their local microenvironment. The microglia rapidly change their phenotype in response to any disturbance of nervous system homeostasis and are commonly referred to as activated on the basis of the changes in their morphology or expression of cell surface antigens. A wealth of data now demonstrate that the microglia have very diverse effector functions, in line with macrophage populations in other organs. The term activated microglia needs to be qualified to reflect the distinct and very different states of activation-associated effector functions in different disease states. Manipulating the effector functions of microglia has the potential to modify the outcome of diverse neurological diseases.
Human Marginal Zone B Cells
Authors: Weill Jean-Claude , Weller Sandra , Reynaud Claude-Agnès
Published: March 2009

Human marginal zone (MZ) B cells are, in a sense, a new entity. Although they share many properties with their mouse counterpart, they also display striking differences, such as the capacity to recirculate and the presence of somatic mutations in their B cell receptor. These differences are the reason they are often not considered a separate, rodent-like B cell lineage, but rather are considered IgM memory B cells. We review here our present knowledge concerning this subset and the arguments in favor of the proposition that humans have evolved for their MZ B cell compartment a separate B cell population that develops and diversifies its Ig receptor during ontogeny outside T-dependent or T-independent immune responses.
Immune and Inflammatory Mechanisms of Atherosclerosis
Authors: Galkina Elena , Ley Klaus
Published: March 2009

Atherosclerosis is an inflammatory disease of the wall of large- and medium-sized arteries that is precipitated by elevated levels of low-density lipoprotein (LDL) cholesterol in the blood. Although dendritic cells (DCs) and lymphocytes are found in the adventitia of normal arteries, their number is greatly expanded and their distribution changed in human and mouse atherosclerotic arteries. Macrophages, DCs, foam cells, lymphocytes, and other inflammatory cells are found in the intimal atherosclerotic lesions. Beneath these lesions, adventitial leukocytes organize in clusters that resemble tertiary lymphoid tissues. Experimental interventions can reduce the number of available blood monocytes, from which macrophages and most DCs and foam cells are derived, and reduce atherosclerotic lesion burden without altering blood lipids. Under proatherogenic conditions, nitric oxide production from endothelial cells is reduced and the burden of reactive oxygen species (ROS) and advanced glycation end products (AGE) is increased. Incapacitating ROS-generating NADPH oxidase or the receptor for AGE (RAGE) has beneficial effects. Targeting inflammatory adhesion molecules also reduces atherosclerosis. Conversely, removing or blocking IL-10 or TGF-β accelerates atherosclerosis. Regulatory T cells and B1 cells secreting natural antibodies are atheroprotective. This review summarizes our current understanding of inflammatory and immune mechanisms in atherosclerosis.
The Liver as a Lymphoid Organ
Authors: Crispe Ian Nicholas
Published: March 2009

The liver receives blood from both the systemic circulation and the intestine, and in distinctive, thin-walled sinusoids this mixture passes over a large macrophage population, termed Kupffer cells. The exposure of liver cells to antigens, and to microbial products derived from the intestinal bacteria, has resulted in a distinctive local immune environment. Innate lymphocytes, including both natural killer cells and natural killer T cells, are unusually abundant in the liver. Multiple populations of nonhematopoietic liver cells, including sinusoidal endothelial cells, stellate cells located in the subendothelial space, and liver parenchymal cells, take on the roles of antigen-presenting cells. These cells present antigen in the context of immunosuppressive cytokines and inhibitory cell surface ligands, and immune responses to liver antigens often result in tolerance. Important human pathogens, including hepatitis C virus and the malaria parasite, exploit the liver's environment, subvert immunity, and establish persistent infection.
Regulatory T Cells in the Control of Host-Microorganism Interactions
Authors: Belkaid Yasmine , Tarbell Kristin
Published: March 2009

Each microenvironment requires a specific set of regulatory elements that are finely and constantly tuned to maintain local homeostasis. Various populations of regulatory T cells contribute to the maintenance of this equilibrium and establishment of controlled immune responses. In particular, regulatory T cells limit the magnitude of effector responses, which may result in failure to adequately control infection. However, regulatory T cells also help limit collateral tissue damage caused by vigorous antimicrobial immune responses against pathogenic microbes as well as commensals. In this review, we describe various situations in which the balance between regulatory T cells and effector immune functions influence the outcome of host-microorganism coexistence and discuss current hypotheses and points of polemic associated with the origin, target, and antigen specificity of both endogenous and induced regulatory T cells during these interactions.
Horror Autoinflammaticus: The Molecular Pathophysiology of Autoinflammatory Disease
Authors: Masters Seth L. , Simon Anna , Aksentijevich Ivona , Kastner Daniel L.
Published: March 2009

The autoinflammatory diseases are characterized by seemingly unprovoked episodes of inflammation, without high-titer autoantibodies or antigen-specific T cells. The concept was proposed ten years ago with the identification of the genes underlying hereditary periodic fever syndromes. This nosology has taken root because of the dramatic advances in our knowledge of the genetic basis of both mendelian and complex autoinflammatory diseases, and with the recognition that these illnesses derive from genetic variants of the innate immune system. Herein we propose an updated classification scheme based on the molecular insights garnered over the past decade, supplanting a clinical classification that has served well but is opaque to the genetic, immunologic, and therapeutic interrelationships now before us. We define six categories of autoinflammatory disease: IL-1β activation disorders (inflammasomopathies), NF-κB activation syndromes, protein misfolding disorders, complement regulatory diseases, disturbances in cytokine signaling, and macrophage activation syndromes. A system based on molecular pathophysiology will bring greater clarity to our discourse while catalyzing new hypotheses both at the bench and at the bedside.
Corrosion of a Zr-based Bulk Metallic Glass with Different Surface Finishing States
Authors: Gebert Annett , Gostin Flaviu , Kühn Uta , Schultz Ludwig
Published: March 2009

The Zr59Ti3Cu20Al10Ni8 bulk metallic glass has been studied regarding the effect of surface finishing states on its anodic behavior in 0.01 M Na2SO4 (pH=7) without / with 0.01 M NaCl. The anodic response of the alloy ground to grid 4000 depends on the pre-immersion time at OCP during which the surface gradually passivates. Fine polishing with diamond suspension does not significantly alter the passivation properties. But fine polishing with SiO2-based suspension may cause similar as 1 % HF etching a Cu enrichment at the alloy surface leading to an enhanced active dissolution. Fine polishing increases the pitting susceptibility.
Morphological and Structural Properties of β-Ga2O3 Nanostructures
Authors: Yasuda Takahito , Yang Qing , Honda Satoshi , Ogino Kazuki , Tatsuoka Hirokazu , Tanaka Miyoko , Brown Paul
Published: March 2009

β-Ga2O3 nanowires and nanobelts were synthesized by the thermal oxidation of Ga with Cu5Si or CaSi2 powders, and the morphological and structural properties of the β-Ga2O3 nanostructures have been investigated. It was found that not only the growth morphology, but also the optical property depends on the oxidation conditions of the nanostructures. The β-Ga2O3 nanowires show a UV luminescence around 370 nm under the excitation of He-Cd at 325 nm. On the other hand, the nanobelts show blue emissions around 450 nm. As a comparison, the nanostructures were synthesized by the thermal oxidation of only Ga. The defect features of the nanostructures are discussed in consideration with their optical properties. The results encourage us to control the morphological and structural properties of the nanostructures in relation to their optical properties.
Compositional Phase Transition of Amorphous AlON
Authors: Yoshida Shinji , Orita Kenji , Hasegawa Yoshidaki , Mochida Atsunori , Takigawa Shinichi
Published: March 2009

We have clarified the compositional dependence of the thermal stabilities and chemical structures of aluminum oxynitride (AlON) films. Thermally induced changes in composition and structure of AlON with various compositional ratio (R=N/(N+O)) have been investigated. Although AlON films show amorphous phase in the wide range of R, we find that AlON has two chemically different phases with different thermal stability, which are separated at critical nitrogen composition of R=0.4. Rutherford back scattering measurement and infrared spectroscopy indicate that AlON with R<0.4 shows structural phase transition and nitrogen desorption occurred by thermal annealing. In contrast, AlON with R>0.4 is thermally stable amorphous phase. We propose a model of bonding structure which explains the thermal stability of AlON.
The Effects of Deposition and Processing Parameters on the Electronic Structure and Photoluminescence from Nitride-Passivated Silicon Nanoclusters
Authors: Wilson Patrick R. , Roschuk Tyler , Zalloum Othman , Wojcik Jacek , Mascher P.
Published: March 2009

Silicon nanoclusters (Si-ncs) embedded in silicon nitride films have been studied to determine the effect that deposition and processing parameters have on their growth, luminescent properties, and electronic structure. Luminescence was observed from Si-ncs formed in silicon-rich silicon nitride films with a broad range of compositions and grown using three different chemical vapour deposition (CVD) based systems: plasma-enhanced CVD (PECVD), inductively coupled plasma CVD (ICP CVD), and electron cyclotron resonance PECVD (ECR PECVD). Photoluminescence experiments revealed broad, tunable emissions with peaks ranging from the near-infrared across the full visible spectrum. The emission energy was highly dependent on the film composition and changed only slightly with annealing, which primarily affected the emission intensity. X-ray absorption spectra at the Si K- and L3,2-edges exhibited composition dependent phase separation and structural re-ordering of the Si-ncs and silicon nitride host matrix under different post-deposition annealing conditions.
About the Insoluble to the Soluble Prussian Blue Transformation
Authors: Agrisuelas Jerónimo , García-Jareño José Juan , Giménez-Romero David , Vicente Francisco
Published: March 2009

Interfacial and nano-gravimetric results are analyzed together with spectro-electrochemical in situ results in order to study the electrochemical transformation of the Prussian Blue films from the freshly deposited to the stable form. This is a complex process that implies apparently the lost of water molecules and the entrance of potassium ions into the ferrocyanide vacancies of the crystalline structure.
Alkaline Water Electrolysis Resistance Evolution at Normal Earth Gravity and Under Zero Gravity Conditions
Authors: Mandin Philippe P. , Le Graverend Jean-Briac , Wüthrich Rolf , Fukunaka Yasuhiro
Published: March 2009

The goal of the present work is to present both experimental and numerical modelling of the gas production, during a two-phase electrolysis process: the alkaline water electrolysis. Numerical and experimental results obtained at normal and zero gravity will be presented. This possibility of zero gravity experiments allows the study of electrochemical performances in absence of natural convective transport. Particularly, such results allow input data identification and give accurate validation benchmark for numerical modelling.
Controlling Ce3+ Emission Color in Silicate Garnet Phosphor
Authors: Prasanth Nammalwar K. , Kishore Manepalli S. , Chandran R. G. , Setlur Anant
Published: March 2009

In this report, we discuss the crystal chemistry and luminescence properties of Ce3+ activated Lu2-xCa1+xMg2-xScxSi3O12 garnets. We identify that the previously published silicate garnets, Lu2CaMg2Si3O12 and Ca3Sc2Si3O12 form a full solid solution with Sc3+ primarily substituting for Mg2+ in octahedral and Ca2+ substitution in the dodecahedral sites. Within this solid solution, both the lowest energy Ce3+ 4f1®5d1 excitation peak and the Ce3+ 5d1® 4f1 emission peak blueshifts as x increases with emission maximum for x = 0 at ~605nm and x =2 at ~505nm. The reasons for this blueshift in the luminescence spectra is discussed as well as the thermal quenching of these phosphors as a function of composition
Synthesis and Physical Properties of Organogels based on Low Molecular Weight Gelators: 4-(2-perfluoroalkyl)ethylthiobenezene Derivatives
Authors: Iuchi Ayuko , Morita Yuki , Hirakawa Tomomi , Kasatani Kazuo , Okamoto Hiroaki
Published: March 2009

Several derivatives for 4-(2-perfluoroalkyl)ethylthiobenzene were prepared and their gelation properties were investigated. The alkyl and alkylene derivatives formed organogels with polar and non-polar organic solvents such as alcohols, tolunene, N,N-dimethylformamide, acetonitrile and propylenecarbonate. The thermal properties for these organogels are revealed to be thermo-reversible physical gels. Furthermore, organogel electrolyte using alkyl derivative was prepared from LiPF6 as a supporting electrolyte and mixed solvent of ethylene carbonate and dimethyl carbonate, and the ionic conductivities of gel electrolyte and that of the corresponding electrolyte solution were examined.
Electrodeposition of High-Tc Superconducting Bi-Sr-Ca-CuO Nanostructures
Authors: Abbott Silky , Gunasekaran R. A. , Young David P. , Singh Varshni , Davis Despina
Published: March 2009

We report on the reproducible growth of superconducting (Bi1-xPbx)2Sr2CuO6+δ and (Bi1-xPbx)2Sr2Ca2Cu3O10+δ nanostructures, which has been a major difficulty in the electrochemical deposition of thin films of BSCCO. The precursors of superconducting Bi(Pb)-Sr-Ca-CuO were electrodeposited in an electrolytic bath prepared from the nitrate salts of the constituent metals in an organic solvent, dimethylsulfoxide (DMSO). The superconductor was electrodeposited in the form of nanotubes and nanowires. The as-deposited samples were given a controlled oxidative thermal treatment in air. The influence of deposition potential, annealing temperature and pH was studied and optimized to get the desired stoichiometry, 2201 and 2223 phase of superconducting Bi(Pb)-Sr-Ca-CuO. A novel three-step electrodeposition scheme was implemented to control the elemental stoichiometry specifically, the oxygen stoichiometry in the sample. Characterization of the electrodeposited and annealed nanostructures was done using XRD, EDS, SEM and PPMS. A plausible theoretical interpretation is given to explain the purpose behind the electrodepositing nanostructures.
Evaluation of PEFC Stack Performance and Effects of Cooling Failure
Authors: Okano Jun , Matsushita Yoshio , Okajima Keiichi
Published: March 2009

Polymer electrolyte fuel cell (PEFC) has advantages because of less environmental impact and high system efficiency. It is expected to use many applications such as fuel cell vehicles, residential fuel cell systems. However, there are many technical problems to overcome for the practical use of fuel cells. In particular, it is important to improve the system reliability and the stack failure diagnosis. In this study, PEFC stack performances and effects of cooling failure were investigated. From the result, voltage deviations were calculated in consideration of the Nernst loss caused by the hydrogen partial pressure loss. From the results of a cooling failure test, the plugged cell temperature increased by 8.65 åC at 33 A. The voltage of plugged cell increased on the cooling failure test, though the stack voltage dropped.
An Electronic Perspective On The Electrochemical Changeover In Prussian Blue-Like Materials
Authors: Agrisuelas Jerónimo , Bueno Paulo R. , Ferreira Fabio F. , Gabrielli Claude , García-Jareño José Juan , Giménez-Romero David , Perrot Hubert , Vicente Francisco
Published: March 2009

Derivative voltabsometric scans together with previous electrogravimetric results allow to distinguish between the different electrochemical processes due to Fe-sites located into the Prussian Blue crystalline framework and other located next to ferrocyanide vacancies. The potassium, proton and hydrated proton counterions involved in these reactions are correlated to changes in near-UV/VIS/near-IR spectra. Potassium counter-ions show two different sites for insertion: one located into the crystalline framework and the other into ferrocyanide vacancies. From the monitoring of electroactive Fe-sites, it is possible to assume that the reduction of all Fe-sites located next to ferrocyanide vacancies is responsible for the PB magnetic ordering observed at room temperature.
Thermodynamic Modeling of a Tubular High-Temperature Steam Electrolyzer Cell
Authors: Gauthier Wilfried , Delhomme Catherine , Vulliet Julien , Rochais Denis
Published: March 2009

High-Temperature Steam Electrolysis (HTSE) is a promising method for highly efficient large-scale hydrogen production. In our study, a theoretical model was developed to describe the evolution of the electrochemical reaction along a tubular cell of a High-Temperature Steam Electrolyzer. The model is based on the Nernst relation with classical sources of voltage loss. The developed model allows the evolution of the current density to be calculated along the tubular cell thanks to a fine longitudinal discrimination of the cylinder. The results show that the current density, and so the heat production, decreases along the tubular cell. The temperature of gaseous species along the cylinder is evaluated as well as hydrogen and oxygen production and steam consumption. Therefore, thickness, porosity, tortuosity and pore radius size of the electrodes are considered. At last, iterating the model for different voltages give the entire current-voltage curve (J-V), characteristic of the cell. Parametric analyses are finally performed to determine the effect of materials properties and operating parameters.
Nanoimprint of Polymer Electrolyte Membrane for Micro Direct Methanol Fuel Cell Application
Authors: Zhang Yi , Lu Jian , Wang Qing , Takahashi Masakaru , Itoh Toshihiro , Ryutaro Maeda
Published: March 2009

This paper reviews current progress on the miniaturization of direct methanol fuel cell (DMFC) by micro-electro-mechanical systems (MEMS) technology. MEMS-based DMFC has low performance because of low catalyst efficiency. Thermal nanoimprint technology is presented as an attractive method for achieving high catalyst efficiency. Fine patterns were directly formed on Nafion 117 membrane by using thermal nanoimprint method. With passive feeding of 1 M methanol solution and air, the nanoimprinted micro DMFC prototype had a open circuit voltage (OCV) of about 0.74 V and a maximum power density (MPD) of 0.2 mW/cm2, which were much higher than those of the state-of-the-art MEMS-based micro DMFC with similar catalyst loading, suggesting that much higher catalyst efficiency had been realized. This conclusion was also supported by the fuel cell experiments on the nanoimprinted membrane using humidified hydrogen and oxygen at 60oC.
Organic Light-Emitting Diodes Tuned with an External Color Tuning Layer
Authors: Chang Chi-Sheng , Liu Po-Tsun , Chen Chin H. , Chou Yi-Teh
Published: March 2009

Blue phosphorescence OLED devices with an external color tuning layer (ECTL) for the purpose of producing white lighting emission has been fabricated. A graded FIrpic phosphorescent blue device shows a much higher efficiency than one that is not graded, and by applying 1.0wt.% ECTL will produce WOLED with high efficiency of 9.6 cd/A and CIEx,y at (0.31, 0.43), and by using a lower concentration of 0.5wt.% ECTL, the efficiency will even reach 12.6 cd/A and CIEx,y at (0.25, 0.43). It is demonstrated that this methodology provides an easy fabrication process for producing highly efficient WOLED devices with tunable colors.
Theoretical Analysis of Phosphors Based on First-Principles Cluster Calculations Using the Relativistic DVME Method
Authors: Yoshida Hisashi , Ogasawara Kazuyoshi
Published: March 2009

We have performed the theoretical calculations on the electronic structures of host crystals used for phosphors and those of rare-earth-doped phosphors using the computational programs of the relativistic discrete-variational Xα potential (DV-Xα) method and one of its extension programs known as the discrete-variational multi-electron (DVME) method. Both of them are powerful tools for the study of the optical properties of conventional and novel phosphors.
Luminescence of Ce3+ in the Scandate Perovskites
Authors: Setlur Anant , Happek U.
Published: March 2009

The luminescence of Ce3+ in scandate perovskite hosts is investigated in this report. In general, the energy position of the Ce3+ excitation and emission bands are at lower energy versus comparable Al3+ perovskites, which is primarily attributed to a larger Ce3+ 5d1 centroid shift. The efficiency of Ce3+ luminescence is low at room temperature (<10% of the low temperature value), and it is shown through both comparisons to other perovskites and direct measurements that Ce3+ luminescence quenching in the scandate perovskites is primarily due to photoionization.
Luminescent Properties of Two Kinds of Newly Synthesized Metal Organic Frameworks(MOF's) Containing Trivalent Europium and Terbium
Authors: Taoyun Zhu , Uematsu Kazuyoshi , Ishigaki Tadashi , Toda Kenji , Sato Mineo
Published: March 2009

Using pyridine-2,4-dicarboxylic(2,4-dipic) and pyridine-3,5-dicarboxylic(3,5-dipic) acids as ligands for trivalent europium and terbium atoms, three types of MOFs were succefully synthesized by a hydrothermal condition, and their structures were solved by single X-ray diffraction analysis. The chemical formula of the MOFs were confirmed as [Eu3(2,4-dipic)4 (2,4-dipicH)]·11H2O, [Eu2(3,5-dipic)3]·4H2O, and [Tb2(3,5-dipic)3]·17H2O. The thermal stability and luminescent properties for these conpound were investigated.
Characterization of High Luminance Red Phosphor (Y,Gd)2O3:Eu for Cold Cathode Fluorescent Lamps
Authors: Okishiro Kenji , Shiiki Masatoshi , Imamura Shin , Okazaki Choichiro
Published: March 2009

The optical properties of (Y,Gd)2O3:Eu and Y2O3:Eu were examined under both UV and VUV excitation. The evaluation found that the optical properties were greatly different between VUV and UV excitation. Higher luminance and shorter afterglow were also confirmed in comparison with Y2O3:Eu. Additionally, the temperature dependence of the luminance was improved by Gd substitution.
Electrolytic Metal Coatings and Metal Finishing Using Ionic Liquids
Authors: Abbott Andrew , Barron J. C. , Elhadi M. , Frisch G. , Gurman S. J. , Hillman A. R. , Smith E. L. , Mohamoud M. A. , Ryder Karl S.
Published: March 2009

Here we describe the electrolytic deposition of a range of metallic coatings, alloys and composites from room temperature ionic liquids that have low environmental impact/toxicity, are inexpensive and easy to handle. We show that some of these systems can be considered as "drop-in" replacement technologies for existing aqueous processes that currently utilize strong inorganic acids and highly toxic reagents.
Do You REALLY Want a High Potential Cathode ?
Authors: Huggins Robert A.
Published: March 2009

Many investigations of high potential cathodes in lithium systems have shown evidence of oxygen evolution, which can lead to thermal runaway problems. It will be shown that this is to be expected on the basis of thermodynamic considerations. Experiments involving 10 phases in the Li-Co-O, Li-Fe-O and Li-Mn-O systems were performed in a glove box over a limited range of both oxygen pressure and voltage, and the results interpreted in terms of ternary phase stability diagrams. They showed a linear relation between the logarithm of the equilibrium oxygen pressure and the potential, independent of both the chemical compositions and the crystal structures of the phases involved. Extrapolation to higher potentials indicates very high values of the equilibrium oxygen pressures in high voltage cathode materials. These results show that the critical issue related to the equilibrium oxygen pressure of high potential cathodes is their potential, not their compositions or crystal structures.
Organic Compound/Metal Oxide Hybrid Thin Film Prepared by the Liquid Phase Deposition Method
Authors: Deki Shigehito , Kodama Yasuaki , Mizuhata Minoru
Published: March 2009

Organic compound/metal oxide composite thin films have been prepared by the liquid-phase deposition method in one-step deposition technique. Organic dyes were added to the metal fluoro-complexes aqueous solution in order to entrap these dyes within the growing thin films of metal oxides, yielding organic dye/metal oxide hybrid materials. According to Raman spectroscopy and X-ray photoelectron spectroscopy, the formation of the materials in the case of cationic dyes can be explained by electrostatic interaction between negative charge density at the fluorinated surface of metal oxides and the cationic dyes. UV-Vis results indicate that stilbazo and pyrocatechol violet (catecholate dye molecules) form a charge transfer complex with metal oxides through the catechol moiety with a bidentate linkage.
Preparation of Perovskite-Type Oxide Fine-Powder by Polymer Precursor Method
Authors: Takase Satoko , Suzuki Soichiro , Matsumoto Toshikazu , Shimizu Youichi
Published: March 2009

We have examined the effects of chelating agents and anti-sintering aids for the preparation of perovskite-type oxide fine powders by a polymer precursor method at low temperature. The single SmFeO3 phase was obtained at the low temperature of 600ºC by using ethylenediamine for chelating agent, however the specific surface area of the powders obtained at low temperature still showed relatively small surface areas due to sintering. Therefore, anti-sintering aids were tried to use at calcining process. It was found that the use of anti-sintering aid at calcining process not only prevented the sintering but also lowered the calcination temperatures to obtain a single phase perovskite-type oxide.
Novel High Molecular Weight Levelers Extending Gap Fill to Smaller Features
Authors: Adolf James , Akolkar Rohan , Landau Uziel
Published: March 2009

It has been recently demonstrated that a high molecular weight leveler can improve gap fill, in addition to minimizing the overburden (1). An analysis of this phenomenon and a quantitative model explaining the effect are presented here. The penetration of the high molecular weight leveler into the via is restricted due to its large size and slow diffusion, leading to preferential passivation of the wafer top surface. Since the leveler is a strong inhibitor, the applied current is therefore preferentially directed into the vias. Because the side walls are passivated by PEG, the majority of this current is directed to the via bottom, improving bottom-up fill. The process conditions and the distribution of features on the wafer affect this improvement. The model has been quantified using a computer implemented simulation combining empirical and analytical methods. Requirements for suitable additives for this application are specified, identifying polyethylenimine as one such additive.
Copper ECD Process of ULSI Circuits Controlled by Electroanalysis Combined with Multi-way Chemometrics. Transfer of the PARAFAC/ILS Calibration
Authors: Jaworski Aleksander R. , Wikiel Hanna , Wikiel Kazimierz
Published: March 2009

Since the emergence of ECD copper for damascene processing in the late 1990's, reductions in the sizes of trenches and vias in ULSI circuits have been placing increasingly stringent demands on plating bath control in order to satisfy strict chip manufacturing standards. The optimization of the manufacturing of electronic components, resulting in cost minimization, while fulfilling process specifications, can only be achieved by accurate concentration monitoring and control of the multicomponent plating baths. The Real Time Analyzer (RTA) utilizing a variety of voltammetric techniques is an in-situ, on-line monitoring system that provides a complete chemical analysis of different plating solutions. This presentation addresses several issues associated with multi-way calibration transfer (also known as instrument standardization) routines. As only one calibration model (i.e., master calibration) is required after standardization for concentration predictions on numerous secondary systems, the calibration transfer allows exchangeability among RTA systems and/or their critical components.