The Relationship Between Nanoscale Structure and Electrochemical Properties of Vanadium Oxide Nanorolls

In this paper, we explore the relationship between the nanoscale structure and electrochemical performance of nanoscale scrolls of vanadium oxides (vanadium oxide nanorolls). The vanadium oxide nanorolls, which are synthesized through a ligand‐assisted templating method, exhibit different morphologies and properties depending upon the synthetic conditions. Under highly reducing conditions, nearly perfect scrolls can be produced which have essentially no cracks in the walls (well‐ordered nanorolls). If the materials are produced under less reducing conditions, nanorolls with many cracks in the oxide walls can be generated (defect‐rich nanorolls). Both types of samples were examined by X‐ray diffraction (XRD), transmission electron microscopy (TEM), and X‐ray photoemission spectroscopy (XPS) to characterize their local structure, local redox state, and nanoscale structure. After ion‐exchange to replace the templating ammonium ions with Na⁺, the ability of these materials to electrochemically intercalate lithium reversibly was investigated. In sweep voltammetry experiments, the well‐ordered nanorolls showed responses similar to those seen in crystalline orthorhombic V₂O₅. In contrast, the defect‐rich vanadium oxide nanorolls behaved electrochemically more like sol–gel‐prepared vanadium oxide materials. Moreover, the specific capacity of the well‐ordered nanorolls was about 240 mA h g^–1 while that of the defect rich nanorolls was found to be as much as 340 mA h g^–1 under these same conditions. Disorders on both the atomic and nanometer length scales are believed to contribute to this difference.     

An optimization‐based domain decomposition method for the Boussinesq equations

We study an optimization based domain decomposition method for the Boussinesq equations governing natural convection problems. Domain decomposition is cast into a constrained minimization problem for which the objective functional measures the jump in the dependent variables across the interface between solid and fluid subdomains. We showthat solutions of the minimization problem exist and derive an optimality system from which these solutions may be determined. Finite element approximations of the solutions of the optimality system are examined. The domain decomposition method is also reformulated as a nonlinear least‐squares problem and the results of some numerical experiments are given. © 2002 John Wiley & Sons, Inc. Numer Methods Partial Differential Eq 18: 1–25, 2002     

Simple reversible energy recovery logic using NMOS switch networkswith cross-coupled PMOS pair

A simpler reversible energy recovery logic is proposed, called feedback RERL, based on the previously presented reversible energy recovery logic (RERL), which does not have any nonadiabatic losses     

Digital DBS system design and implementation for TV and databroadcasting using Koreasat

A digital DBS system was developed in order to provide TV and data broadcasting services over the Korean Peninsula using Koreasat. The system was designed and implemented to have studio quality video, CD quality audio, a multilingual broadcasting service, closed captioning service, 4×3/16×9 picture aspect ratio, data services supporting up to 2 Mbps, 99.99% system availability, 99% link availability at the worst month, and pay-channel broadcasting with 500 million subscribers. This paper introduces its functional requirements, system design, and implementation     

Highly reliable flip-chip-on-flex package using multilayered anisotropic conductive film

Anisotropic conductive film (ACF) has been used as interconnect material for flat-panel display module packages, such as liquid crystal displays (LCDs) in the technologies of tape automated bonding (TAB), chip-on-glass (COG), chip-on-film (COF), and chip-on-board (COB). Among them, COF is a relatively new technology after TAB and COG bonding, and its requirement for ACF becomes more stringent because of the need of high adhesion and fine-pitch interconnection. To meet these demands, strong interfacial adhesion between the ACF, substrate, and chip is a major issue. We have developed a multilayered ACF that has functional layers on both sides of a conventional ACF layer to improve the wetting properties of the resin on two-layer flex for better interface adhesion and to control the flow of conductive particles during thermocompression bonding and the resulting reliability of the interconnection using ACF. To investigate the enhancement of electrical properties and reliability of multilayered ACF in COF assemblies, we evaluated the performance in contact resistance and adhesion strength of a multilayered ACF and single-layered ACF under various environmental tests, such as a thermal cycling test (−55°C/+160°C, 1,000 cycles), a high-temperature humidity test (85°C/85% RH, 1,000 h), and a high-temperature storage test (150°C, 1,000 h). The contact resistance of the multilayered ACF joint was in an acceptable range of around a 10% increase of the initial value during the 85°C/85% RH test compared with the single-layered ACF because of the stronger moisture resistance of the multilayered ACF and flex substrate. The multilayered ACF has better adhesion properties compared with the conventional single-layered ACF during the 85°C/85% RH test because of the enhancement of the wetting to the surface of the polymide (PI) flex substrate with an adhesion-promoting nonconductive film (NCF) layer of multilayered ACF. The new ACF of the multilayered structure was successfully demonstrated in a fine-pitch COF module with a two-layer flex substrate.     

Leveraging single rate schemes in multiple rate multicast congestion control design

A significant impediment to deployment of multicast services is the daunting technical complexity of developing, testing and validating congestion control protocols fit for wide-area deployment. Protocols such as pragmatic general multicast congestion control (pgmcc) and TCP-friendly multicast congestion control (TFMCC) have recently made considerable progress on the single rate case, i.e., where one dynamic reception rate is maintained for all receivers in the session. However, these protocols have limited applicability, since scaling to session sizes beyond tens of participants with heterogeneous available bandwidth necessitates the use of multiple rate protocols. Unfortunately, while existing multiple rate protocols exhibit better scalability, they are both less mature than single rate protocols and suffer from high complexity. We propose a new approach to multiple rate congestion control that leverages proven single rate congestion control methods by orchestrating an ensemble of independently controlled single rate sessions. We describe a new multiple rate congestion control algorithm for layered multicast sessions that employs a single rate multicast congestion control as the primary underlying control mechanism for each layer. Our new scheme combines the benefits of single rate congestion control with the scalability and flexibility of multiple rates to provide a sound multiple rate multicast congestion control policy.     

Stability improvement of V/f-controlled induction motor drive systems by a dynamic current compensator

Stability improvement of V/f-controlled induction motor drive systems by a dynamic current compensator is proposed. The proposed method uses a dynamic current compensator to improve the stability of the V/f-controlled induction motor drive systems. This method is easy to implement and helps eliminate the oscillations causing the instability of V/f-controlled induction motor drive systems.     

A high-order accurate hybrid scheme using a central flux scheme and a WENO scheme for compressible flowfield analysis

A high-order accurate hybrid central-WENO scheme is proposed. The fifth order WENO scheme [G.S. Jiang, C.W. Shu, Efficient implementation of weighted ENO schemes, J. Comput. Phys. 126 (1996) 202–228] is divided into two parts, a central flux part and a numerical dissipation part, and is coupled with a central flux scheme. Two sub-schemes, the WENO scheme and the central flux scheme, are hybridized by means of a weighting function that indicates the local smoothness of the flowfields. The derived hybrid central-WENO scheme is written as a combination of the central flux scheme and the numerical dissipation of the fifth order WENO scheme, which is controlled adaptively by a weighting function. The structure of the proposed hybrid central-WENO scheme is similar to that of the YSD-type filter scheme [H.C. Yee, N.D. Sandham, M.J. Djomehri, Low-dissipative high-order shock-capturing methods using characteristic-based filters, J. Comput. Phys. 150 (1999) 199–238]. Therefore, the proposed hybrid scheme has also certain merits that the YSD-type filter scheme has. The accuracy and efficiency of the developed hybrid central-WENO scheme are investigated through numerical experiments on inviscid and viscous problems. Numerical results show that the proposed hybrid central-WENO scheme can resolve flow features extremely well.     

Preliminary Results of a New Temporary Vocal Fold Injection Material

Temporary vocal fold injection is a valuable procedure for vocal fold paralysis or paresis of uncertain permanency and as a trial augmentation to decide the value of vocal fold augmentation. A new material made from glycerin, carboxymethylcellulose, and water has recently been developed for temporary vocal fold augmentation. Eleven patients underwent vocal fold injection for the treatment of glottal incompetence with this material. The duration of effectiveness of this injection material was 2 to 3 months depending on the injection amount. This new material satisfies several requirements for an ideal temporary vocal fold injection material in terms of injectability, convenience, duration of effectiveness, and safety. The authors conclude that this new material is a good option for temporary vocal fold augmentation.     

Edge Profile Effect of Tunnel Oxide on Erase Threshold-Voltage Distributions in Flash Memory Cells

The erase threshold-voltage (VT) distribution in Flash electrically erasable programmable read-only memory cells was investigated versus the tunnel oxide edge profiles in self-aligned shallow trench isolation (SA-STI) and self-aligned poly (SAP) cells. The capacitive coupling with offset voltage correction is transcribed into VT transient for simulating erase VT dispersion without numerous full structure device simulations. It is shown that SAP gives rise to smaller VT dispersion, compared with SA-STI. The VT dispersion resulting from variations in dielectric thickness and oxide edge profiles is shown to fall far short of observed VT distribution, calling for examination of additional process and cell parameters