bluuebunny/crossref_metadata_2025 huggingface dataset:
Growth Kinetics and Physical Characterization of Low Temperature Anodic Plasma Assisted Oxide of Titanium
Authors: Busani Tito , Devine Roderick
Published: May 2009

Thin layers of Ti were sputtered onto Si wafers and then oxidized using the so-called constant current mode of microwave plasma assisted oxidation. The resulting TiO2, characterized ex situ, was determined to have a density of 4.1 g/cm3 and a refractive index at 633 nm of 2.34. Samples were then annealed in both O2 and N2 atmospheres at 600 ºC for 1 hour. Annealing the TiO2 appears to produce no interaction of the oxide with the Si substrate but re-arrangement of the network occurred resulting in increased packing density. The annealed, anodic TiO2 had a density of 4.25 g/cm3 and a refractive index of 2.38. The dielectric constant was also determined to be 42. No phase transition, from amorphous to rutile or anatase, was observed. The properties of this new amorphous TiO2 polymorph are presented.
High Performance Gate Dielectric for Low Temperature TFTs
Authors: Joshi P. , Voutsas A. , Hartzell J.
Published: May 2009

Low temperature integration of high performance TFTs is critical to realize low cost displays and sensors. The successful development of high performance flexible devices will be dictated by the enhancement in the thermal stability of the flexible substrates and the low temperature processing of the high quality gate dielectric. The low temperature processing of dielectric thin films necessitates the development of processes and techniques with plasma controlled reaction kinetics dominating the thin film growth rather then the thermal state of the substrate. At the same time, the gate dielectric reliability needs to be maintained or enhanced. In the present work, we report on the low temperature processing of high quality gate dielectric films by high-density PECVD technique. The bulk and interfacial electrical quality and reliability of the MOS capacitors as a function of process temperature are discussed in this report. A comparison with the high temperature gate oxide films has been made to establish the film quality and reliability. The present films showed high electrical performance and reliability as evaluated in terms of the electrical, Si/SiO2 interfacial, and bias-temperature stress (BTS) reliability characteristics. The observed results are promising and suggest the suitability of HDP technique for novel device development on low temperature flexible substrates.
Milestones in a Quarter Century of CMP - Plenary
Authors: Fury Michael A.
Published: May 2009

A quarter century has passed since the first semiconductor planarization experiments were conducted in the silicon wafer manufacturing facility in 1983 at IBM in East Fishkill, NY. This paper will review selected highlights of the technology and business drivers that shaped what has become a pervasive, critically enabling process sector in the pursuit of Moore's Law. Since 1988 the segment has grown from zero to $1.2B in capital equipment and $2.0B in consumable materials and ancillaries annually. The fundamental CMP process consisting of a polisher, slurry and pad has spawned a supply chain of no fewer than 18 uniquely identifiable CMP-related product lines and countless businesses. CMP has indeed matured, with an overall growth rate that matches but no longer exceeds that of the industry to which it has become so vital. The paper will conclude with an outlook for the near-term growth opportunities for CMP.
Effect of Copper CMP Slurry Chemistry on the Rate of Agglomeration of Alumina Particles
Authors: Brahma Neil , Chan Mike , Talbot Jan
Published: May 2009

The rate of agglomeration was measured for alumina particles with and without the copper in KNO3 at various pH values. For solutions without copper, agglomeration was greatest at pH of 7.5, near the isoelectric point of 6.5, at a rate of 82 nm/min, following a reaction-limited mechanism. Solutions with a pH away from the isoelectric point underwent reversible agglomeration, reaching a small agglomerate size at steady-state. The addition of copper did not affect agglomeration at pH 4. However, an increase in the agglomeration rates at pH 7.5 and 10 was observed with copper in the solutions, following a diffusion-limited mechanism.
Effect of Ceria Abrasives on Planarization Efficiency in STI CMP Process
Authors: Park Boumyoung , Kim Youngjin , Kim Hyoungjae , Jeong Haedo , Dornfeld David
Published: May 2009

The strong Ce-O-Si bonding between CeO2 abrasives and SiO2 film surface; i.e., the chemical tooth effect, improved planarization efficiency in CMP using ceria-based slurry as a result of nonlinear behavior of the removal rate. Removal rate is a power function of pressure and relative velocity (i.e., RR=kpavb). In particular, the high dependency of removal rate on pressure when a>1 results in a much higher material removal rate in the upper pattern than in the lower pattern. Therefore, the planarization efficiency of ceria-based slurry is better, from initial polishing time to the completion of the polishing step, than that of conventional silica-based slurry with an exponent value of a=1.
Post-CMP Cleaning of Copper/Hydrophobic Low-k Dielectric Films
Authors: Chen Yufei , Ko Sen-Hou , Xu Kun , Wang Yuchun , Tu Wen-Chiang , Karuppiah Lakshmanan
Published: May 2009

The requirements for copper post-CMP cleaning include slurry particle removal, organic residue removal, metal contamination reduction, water mark elimination, copper corrosion prevention, and low-k surface change minimization. The difficulty in meeting some of these requirements varies with the CMP consumables (e.g. slurry, pad, etc.) used. Over the past ten years, the most significant factor driving changes in copper post-CMP cleaning is low-k surface hydrophobicity. A highly hydrophobic ultra low-k surface provides a significant challenge not only to wafer drying, but also to wafer cleaning and rinsing. In this paper, state-of-the-art post-CMP cleaning of Cu/ultra low-k dielectric films is presented.
NIR Monitoring of CMP Slurries and Post-CMP Cleaning Solutions
Authors: Shalyt Eugene , Liang Guang , Lu Geng , Bratin Peter
Published: May 2009

The Near Infrared Spectroscopy (NIR) is a powerful analytical technique and process control tool, capable of providing simultaneous qualitative and quantitative information on both, solid and dissolved components of CMP slurries, as well as cleaning solutions. This publication will describe the analytical technique and provide multiple examples for NIR monitoring of particle content, oxidant, particle agglomerates and impurities in various commercially available CMP slurries.
Microstructure of Bit Patterned Media and Recording Characteristics in Perpendicular Magnetic Recording
Authors: Muraoka Hiroaki , Nakamura Yoshihisa
Published: May 2009

The recording physics of bit patterned media is studied for areal densities of around 2 Tbits/inch2, focused on number of grains per bit. Write error rate and signal to noise ratio in a function of number of grains are derived as analytical functions based on the statistics theory on the binomial distribution. Modeling of writing process based on the head field gradient and switching field distribution and interference fields, is presented to extract the write-head and media parameters which are necessary to attain a high areal density recording.
Filling of FePt in AAO Nanohole Array by DC Pulsed Electrodeposition
Authors: Mori Hironori , Korenaga Tomoyuki , Hosomi Naoya , Terui Toshifumi , Shingubara Shoso
Published: May 2009

The ferromagnetic nanowires embedded in anodized aluminum oxide (AAO) are important candidates for the perpendicular magnetic recording media. In the current study, we filled FePt in the AAO nanohole arrays using a pulse DC electrodeposition, by changing the ratio between the on-time and the off-time of the pulse. We found it possible to uniformly fill FePt in AAO at the pulse off-time longer than the pulse on-time. Moreover, we found that the filling of FePt became more difficult with the shrinkage of holes diameter from 70 nm to 20 nm.
Investigations on Embedding Nanoparticles by Electroplating
Authors: Wurz Marc C. , Oekermann Torsten , Wagner Piotre , Ruffert Christine , Caro Juergen , Gatzen H. H.
Published: May 2009

To create a surface suitable for tribological applications, a layer of nanoparticles was deposited on a metal coated substrate, followed by embedding the nanoparticles in a metal matrix. For the deposition, TiO2 and SiO2 nanoparticles were used, followed by a Cu embedding by electroplating. TiO2 particles failed to deliver satisfying results due to agglomeration. The results coming closest to achieving a monolayer were obtained with SiO2 nanoparticles. For the deposition, the SiO2 nanoparticles were attracted to the surface by utilizing zeta potential differences between the surface and the nanoparticles. To achieve an optimal zeta potential, the pH value of the deposition solution was adjusted appropriately. After their deposition, the SiO2 nanoparticles were attached to the surface by heat treatment. Afterwards, the SiO2 nanoparticles were embedded by electroplating. Best electroplating results were achieved on SiO2 nanoparticle layers with no continuous surface coverage, i.e. occasional voids between the nanoparticles.
Novel Thermoelectric Cooling of Magnetic Sensors
Authors: Mannam Raja , Agarwal Mangilal , Roy Amitava , Singh Varshni , Varahramyan Kody , Davis Despina
Published: May 2009

In situ thermoelectric cooling of GMR nanowires is a novel method to obtain reliable and more sensitive GMR devices. Bismuth telluride (BixTey) caps were used to provide localized thermoelectric cooling of GMR nanowires. BixTey nanowires were electrodeposited from aqueous acidic solutions containing different Bi3+ and HTeO2+ concentrations. GMR layered structures were electrodeposited from a Co-rich electrolyte using a pulsed potential technique. The highest Seebeck coefficients of -318.7 µV/K and 117 µV/K were measured for n-type and p-type nanowires, respectively. P-type nanowires were obtained for low Te concentrations (<30%). Initial experiments were conducted to study the effect of thermoelectric cooling on sensitivity of GMR nanowires. Results showed that using BixTey caps can improve magnetic sensitivity of GMR nanowires.
Magnetostrictive TMR Sensors for Mechanical Measurements
Authors: Quandt Eckhard , Meyners Dirk , Von Hofe Thomas , Malavé Antonio
Published: May 2009

Magnetostrictive TMR sensors present a unique possibility to integrate highly sensitive strain sensors on micromachined membranes for sophisticated pressure sensors. The gauge factor of such strain sensors was 840. Using them on micromachined membranes an almost linear dependency between the resistance and the applied pressure was found. The resistance change was approximately 1 Ohm/mbar in a pressure range between 0 and 0.08 bar.
U.S. Department of Energy's SECA Program: 2008 Progress and Plans
Authors: Surdoval Wayne
Published: May 2009

The U.S. Department of Energy's (DOE) Office of Fossil Energy's (FE) National Energy Technology Laboratory (NETL), in partnership with private industry, educational institutions and national laboratories, is leading the research, development, and demonstration of high efficiency, fuel flexible solid oxide fuel cells (SOFCs) and coal-based SOFC power generation systems for stationary market large central power plants. The FE Fuel Cell Program has three parts under the Solid State Energy Conversion Alliance (SECA): cost reduction, coal-based systems, and research and development. The SECA cost reduction goal is to have SOFCs capable of being manufactured at $400 per kilowatt (kW) by 2010. Concurrently, the scale-up, aggregation, and integration of the technology will progress in parallel leading to prototype validation of megawatt (MW)-class fuel flexible products by 2012. The SECA coal-based systems goal is the development of large (greater than 100 MW) integrated gasification fuel cell (IGFC) power systems.
Development of Solid Oxide Fuel Cells at Versa Power Systems
Authors: Borglum Brian
Published: May 2009

Versa Power Systems (VPS) is a developer of solid oxide fuel cells (SOFCs) for clean power generation. VPS has been working with its development partner FuelCell Energy within the U.S. Department of Energy (DOE) Office of Fossil Energy's Solid State Energy Conversion Alliance (SECA) program to apply SOFC technology in large-scale, multi-megawatt power plant systems that utilize coal in a clean and efficient manner. As a result, new initiatives such as widening the temperature of operation (600-800{degree sign}C) and scale-up of the cell and stack are now being actively pursued for these applications.
Coal-Based Solid Oxide Fuel Cell Systems
Authors: Ghezel-Ayagh Hossein , Doyon Jody , Walzak Jim , Jolly Stephen , Patel Dilip , Adriani Allen , Huang Peng , Davis Keith E. , Stauffer David , Vaysman Vladimir , Asapu Sunitha , Borglum Brian , Tang Eric , Petri Randy , Sishtla Chakravarthy
Published: May 2009

FuelCell Energy is developing solid oxide fuel cell (SOFC) technology for very efficient, economically-viable, coal-to-electricity power plants utilizing synthesis gas (syngas) from a coal gasifier (1). One of the key objectives is implementation of an innovative system concept in design of a multi-MW power plant to achieve an electrical efficiency exceeding 50% based on the high heating value (HHV) of coal, exclusive of power requirements for CO2 compression. The system is also designed to remove at least ninety percent of carbon in the syngas, for sequestration as CO2. Combined with CO2 separation technology, the Integrated Gasification Fuel Cell (IGFC) power plant is expected to achieve near-zero emissions to the environment. Development of this technology will significantly advance the nation's energy security and independence interests (through effective utilization of the nation's vast coal reserves), address pollution and greenhouse gas concerns, and help enhance the nation's economic growth.
Advances in Design of Solid Oxide Fuel Cell Hybrid Power Systems for Underwater Applications
Authors: Ghezel-Ayagh Hossein , Junker S. Tobias , Willman Carl , Peters Jonathan A. , Martin Jay , Lowe Dave , Pastula Michael , Tang Eric
Published: May 2009

A hybrid propulsion system for torpedo propulsion applications was developed. The hybrid system utilizes a solid oxide fuel cell (SOFC) to provide low power propulsion and hotel loads supplemented by a high power turbine for high speed pursuit, with both systems using common fuel and oxidant sources. A solid LiClO4 oxidant source was investigated. Individual subsystems including the SOFC stack and LiClO4 oxidant source were physically tested. Trade studies were performed comparing various fuel, oxidant, low power, and high power sources, based on testing performance of the subsystems. The SOFC low power system was demonstrated to provide the longest low power range while maintaining the necessary high power reserve for target pursuit.
Anode Degradation in SOFC: Fuel Impurity Effects on Nickel Component
Authors: Kishimoto Haruo , Yamaji Katsuhiko , Xiong Yue-Ping , Horita Teruhisa , Brito Manuel E. , Yokokawa Harumi
Published: May 2009

Anode degradation behavior in SOFCs operating with liquid hydrocarbon fuel was observed by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). Nickel particles grew from 1 micrometer to more than 3 micrometer in diameter after using desulfurized kerosene in the cell test. From the cross section analysis of SEM/EDX, nickel particles had like a Core-Rim structure and the surface of nickel particle was oxidized by further forced operation of the SOFC cell. On the other hand, the particle growth was negligible and Ni and ScSZ particles were uniformly distributed in the anode when n-dodecane was used.
LSC-Based Composites with Optimal Composition and Microstructure as Current Collecting Materials for Microtubular SOFCs
Authors: Misono Teruhiko , Murata Kenji , Yin Jingtian , Fukui Takehisa
Published: May 2009

A series of LSC/CeO2 composites were prepared as potential air side current collecting materials for micro-tubular SOFCs and their properties were examined and discussed in relation with the composition, microstructure and porosity. The results revealed that the composite specimen with 35 vol.% CeO2 and an open porosity of 73% gave a electrical conductivity of 130 S/cm at 600 ºC, which was 1.4 times as that of the LSCF with a porosity of 61%, and a thermal expansion coefficient of 12.2×10-6 1/ºC between room temperature and 600 {degree sign}C, which was almost the same as that of the LSCF cathode. The composite specimen also demonstrated good stability during a long-term test, suggesting the possibility that they serve as air side current collectors in the micro-tubular SOFCs.
Ni-YSZ SOFC Anode Processing by Mechanical Alloying and Sintering by Activated Surface
Authors: Guisard Restivo Thomaz A. , Mello-Castanho Sonia R.
Published: May 2009

Solid oxide fuel cell is an attractive technology for clean energy generation specially if biofuel feeding can be admitted. The actual challenge is to avoid catalyst poisoning by developing carbon tolerant anode materials. The work investigates copper alloyed Ni-YSZ to meet such requirements, processed by a new route - mechanical alloying MA - which allows the completely mixing and refining of the primary constituent powders. Once the material is obtained, the consolidation is carried out through the sintering by activated surface (SAS) method.
SOFC-based Systems as APU for Regional Jets: a Feasibility Analysis
Authors: Santarelli Massimo , Cabrera Manuel , Calì Quaglia Michele
Published: May 2009

Aviation emissions are growing faster than any other sector and they risk undermining the progress achieved through emission cuts in other areas of the economy. Hydrogen and fuel cell-based technologies could be developed for future replacement of on-board electrical systems in large 'more-electric' or 'all-electric' aircrafts, in order to reduce the emissions at the airport and in high atmosphere. The ENFICA-FC (Environmentally Friendly Inter City Aircraft powered by Fuel Cells) project carries out a feasibility study on all-electric inter-city aircraft to provide a preliminary definition of new typologies of aircraft systems that can be obtained with fuel cell technologies. In this work, a feasibility analysis and a preliminary weight estimation is carried out through the simulation of a complete mission, taking into account two different system configurations for supplying on-board loads of an inter-city aircraft: only-SOFC system and hybrid SOFC-μGT system.
Evaluation of Fuel Cell Performance of Nafion / Molecular Sieves Nanocomposite Membranes
Authors: Hasani-Sadrabadi Mohammad M. , Ghaffarian Seyyed R. , Dashtimoghaddam Erfan
Published: May 2009

Polymeric nanocomposite membranes were prepared through incorporating ZSM-5 type zeolite (SiO2/Al2O3=25) as molecular sieves into Nafion matrix for the direct methanol fuel cells (DMFC) applications. The transport properties of prepared membranes were characterized by measuring the methanol diffusion coefficient and proton conductivity. Nanocomposite membrane with 3.0 wt% ZSM-5 loading showed membrane selectivity of approximately 100,000 in comparison with 40,500 of Nafion117, and also a higher power density (172 mW.cm−2) than Nafion® 117 (108 mW.cm−2) for single cell DMFC in a 5 molar methanol feed.
Testing and Evaluation of a High Temperature PBI Membrane Based PEM Fuel Cell
Authors: Ubong Etim U.
Published: May 2009

A test is conducted on a high temperature PEM membrane based on polybenzimidazole (PBI) doped with phosphoric acid. The impact of various variables such as stoichiometry, temperature and pressure were experimentally evaluated on a single cell. The tests were conducted at steady state conditions and the performance of the membrane was examined. HT-PEMFC is of growing interest to the fuel cell community because of its tolerance of CO up to 5% content. As such, it can be coupled to a reformed fuel unit with less complexity of the balance of plant. It is credited with a higher mechanical strength and chemical stability. The less dependence on humidification simplifies stack design and packaging and the operation at a temperature above 100 oC reduces activation overvoltage. The test results from the voltage-current characteristics used for the analysis revealed that voltage variation with temperature showed an increase and was very predictable and thus can be statistically modeled. The output voltage increased with the increase in pressure from atmospheric to 25 psig while the change in air stoichiometry also improved the performance. The results obtained from this test are useful for modeling and validation of theoretical studies and finds a wide application in optimization exercises.
Parametric Study of a Single Cell PEM Fuel Cell
Authors: Sierra Juan M. , Sebastian Pathiyamattom J. , Gamboa Sergio A.
Published: May 2009

A 3D single cell model of a proton exchange membrane fuel cell (PEMFC) was developed using a computational fluid dynamics software (Fluent 6.3.26). The effect of operating conditions such as pressure, temperature and humidity on the performance of fuel cell was investigated. The study was focused on the activation losses and ohmic resistance. Simulations were performed at three different temperatures 25, 50 and 80 Celsius degrees, at three different gas inlet pressures 1, 2 and 3 atmospheres, and three relative humidity's 25, 50 and 100%. The best results were found when the PEMFC worked at high operating conditions. The analysis showed good agreement with the literature data. The single cell model provided a clear understanding over the influence of operating conditions in the irreversibilities that take place in PEM fuel cells.
Oxide(SnO2,CeO2,Co3O4 and NiO)-Promoted Pt/C Electrocatalysts for PEMFCs
Authors: Jiang Hong , Yu Chi , Huang Zhaofeng , Zhu Hong
Published: May 2009

In this paper the novel PtMOx/C catalyst was innovatively studied. In the preparation process of MOx/C precipitate and PtMOx/C catalyst, we compared different methods. The catalysts prepared by different methods were characterized by TEM, XRD and cyclic voltammeter. The results indicated that the microwave assisted heating of precipitates in ethylene glycol had evidently facilitated the formation of smaller and more uniform particles and their dispersion on the carbon support, and the MOx -promoted Pt/C had significantly higher activity than Pt/C electrocatalyst. It also showed that PtSnO2/C had the best activity for oxygen reduction. So we can conclude that PtSnO2/C is an excellent electrocatalyst which could be widely used for PEMFCs.
Formation of Pt Clusters Covered with Carbon Layer and Origin of the Generation of Electricity
Authors: Kumamoto Akihito , Ohyagi Shinsuke , Kaito Chihiro , Shingu Hiroshi , Suzuki Hitoshi
Published: May 2009

In order to prevent coalescence of platinum clusters on a carbon particle surface, new platinum catalysts covered with a thin carbon layer were proposed. The catalysts were produced by evaporation above the eutectic point between carbon and platinum. Most of the platinum core of 5 nm diameter was covered with a graphene layer of 1 nm thickness. The generation of electricity using this carbon coated platinum surface catalyst in a proton exchange membrane fuel cell has been demonstrated. The mechanism of the generation of electricity has been discussed on the basis of the idea of the contact potential. The electric dipole of water also has been discussed with regard to the generation of electricity.
Effect of Hydrophilic Properties of Gas Channel on Water Management of PEM Fuel Cells
Authors: Shoyama Masashi , Tomimura Testsuya , Mizutani Seiji
Published: May 2009

Effect of hydrophilic and hydrophobic properties of gas channel including bipolar plate and gas diffusion layer on cell performances was developed. It was revealed that cell performance depends on the difference of hydrophilic properties between bipolar plates and GDLs at high flooding conditions, such as high current density, high humidified and low gas stoichiometry.
A New Fuel Supply Method with Flexible Type DMFC
Authors: Tsuchiya Masayuki , Imai Tatsunori , Yachi Toshiaki
Published: May 2009

A new type direct methanol fuel cell (DMFC) with high flexibility has been investigated. The DMFC has new current collecting method, which involves sewing wire to the electrode, and this was examined in an attempt to decrease the contact resistance. The semi-active cell output characteristics were studied using different fuel concentration and flow rate. The contact resistance was significantly reduced using the wire sewing current collection method. The decrease in output voltage was prevented by increasing the fuel concentration and the flow rate of the fuel.
Optimization of Catalyst Deposited Diffusion Layer for a Direct Sodium Borohydride Fuel Cell (DNBFC)
Authors: Miley George H. , Bernas Rob , Kim Kyu-Jung , Luo Nie
Published: May 2009

As part of the development of a portable fuel cell for air independent applications using Direct Sodium Borohydride/Hydrogen Peroxide fuels, we have been studying methods for deposition of the catalysis on the diffusion layer. Optimal conditions (minimum activation, ohmic and transport losses) are obtained in this all liquid fuel cell design when the catalysis is coated throughout the diffusion layer. Catalysis deposition by various electrochemical and sputtering techniques onto a porous carbon cloth diffusion layer is briefly reviewed. We also present preliminary studies of a deposition method designed for use with larger pore diffusion layer materials such as nickel micro felt.
Co-Production of Renewable Hydrogen and Electricity
Authors: Patel Pinakin , Lipp Ludwig , Jahnke Fred , Heydorn Ed , Holcomb Franklin
Published: May 2009

Co-production of renewable hydrogen and electricity using high temperature fuel cells offers a potentially attractive option for the hydrogen infrastructure. The multiple co-products help to increase the overall value proposition. High temperature fuel cell (DFC®) systems produce their own hydrogen internally. Over 60 global units have produced >250 million kWh at customer sites. In California alone, more than 10,000 kg H2/day is being produced in units, mostly from renewable fuels, such as digester gas. Electrochemical Hydrogen Separation (EHS) systems, currently under development at FCE, can separate the hydrogen produced in the DFC® system with relatively low energy consumption and do not require pressurization. The separation process is virtually emission-free. A full-scale EHS stack has been operated for more than 5,000 hours. Plant efficiencies of ~65% are projected for hydrogen + electricity, before waste heat recovery. Technology development status and the potential benefits of this co-production system for civilian as well as military use are discussed.
Development of Advanced Reforming System for H2 Station Using CO Converter Equipped with CO2 Selective Membrane II
Authors: Shimada Keiko , Kuzushita Kaori , Kamio Eiji , Matsuyama Hideto , Ohmura Naoto , Nishiyama Satoru , Mae Kazuhiro , Maki Taisuke , Fujiwara Kazuhiro , Terada Seiji , Umegaki Tetsushi , Okada Osamu
Published: May 2009

We developed a novel membrane reactor consisted of a CO shift catalyst and a membrane for selective CO2 separation. First, we successfully developed novel facilitated transport membranes with excellent performances exceeding our target values, i.e. CO2 permeance of 1x10-4 mol/(m2skPa) and CO2/H2 selectivity of 100 at 160 oC. The developed membrane maintained high performances for more than 400 hours. Second, we developed CO shift catalysts, which had high activity for the CO shift reaction at 160 oC. Among the catalysts developed in this study, precious metal-based catalysts had quite high activities. By combining the developed membrane and catalyst, a membrane reactor-type CO converter was fabricated. By using the CO converter, CO and CO2 concentrations in feed gas (14.8 and 7.4 %, respectively) were drastically reduced. Observed CO and CO2 concentrations at the feed-side exit of the CO converter were 5 ppm and 0.3 %, respectively.
Ultra High Efficiency Direct FuelCell Systems for Premium Power Generation
Authors: Ghezel-Ayagh Hossein , Walzak Jim , Patel Dilip , Jolly Stephen , Lukas Michael , Adriani Allen
Published: May 2009

FuelCell Energy, Inc. (FCE) has been developing Direct FuelCell/Turbine® (DFC/T®) power plants for generation of clean electric power at very high efficiencies. In the DFC/T system, byproduct heat from the fuel cell is used to drive a modified unfired gas turbine to generate additional electricity. The supplemental turbine power increases the system power output and electrical efficiency, and reduces the cost of power generated without using additional fuel. The attractive features of DFC/T hybrid systems include: electrical efficiencies of up to 75% on natural gas fuel, minimal emissions, reduced carbon dioxide release to the environment, simplicity in design, independent operating pressures of the fuel cell and turbine, direct reforming internal to the fuel cell, and commercial cost competitiveness with existing combined-cycle power plants.
Status and Recent Progress of the Internal-manifold Type MCFC Stack Development in Korea
Authors: Kim Seung-Goo , Choi Young-Jae , Kuk Seung Taek , Jun Joonghwan , Lim Hee-Chun
Published: May 2009

In Korea, the research for the development of MCFC stack has been carried out since 1993. The research objective of the ongoing project started in 2004 is the development of 250kW class external reforming type MCFC power generation plant composed of two 125kW class internal-manifold type MCFC sub-stacks. Recently, some remarkable research results including the development of electrolyte impregnated electrodes and 3-piece architecture separators with 7,500cm2 and 10,000cm2 in effective electrode area were achieved. Several 5kw class stack operation tests proved new separators and stack components provided improved stack performances. A 100kW class MCFC stack composed of 130 unit cells with 10,000cm2 in effective electrode area was fabricated to evaluate the new stack concepts. These results will be reflected in the construction and operation of 125 kW class sub-stack and 250 kW class MCFC power generation system.
A Proposal To Future Energy Supplies: Your Personal Power Provider (3P+) Virtual Power Plants with Direct Solar Hydrogen and Fuel Cells
Authors: Evers Arno A.
Published: May 2009

The existing system of production and distribution of electricity creates high flaring and transmission losses. This situation can only be overcome by converting to a decentralized energy system and by implementing new methods of production and distribution. Today's production of hydrogen, storage and utilization are fully dependent upon conventional technologies not commercial feasible. All known technologies produce "black hydrogen" based on fossil fuels, rather than "green hydrogen" via direct solar energy. The ultimate target for hydrogen production is to utilize all renewable energies to produce hydrogen directly with only one conversion step, to eliminate losses and broaden the use of primary energy sources. All processes must be further developed and enriched with new devices and procedures for decentralized, personalized mass- markets. The user and the producer of energy must become one in the same! This will lead to the implementation of hydrogen and fuel cells in a worldwide, mass-market scale.
The Relationship between Electrochemical Impedance Spectra and Photovoltaic Performance Characteristics during the Light and Thermal Ageing of Dye-Sensitized Solar Cells
Authors: Nguyen Hoang T. , Mai Hai Ha T. , Nguyen Phuong Thoa T. , Lund Torben
Published: May 2009

The dye-sensitized solar cells (DSC) based on nano-crystalline titanium dioxide were fabricated and exposed to prolonged light and thermal ageing. Electrochemical impedance spectroscopy has been performed to study the variation of electronic and ionic processes in the DSC during the aging. A model of the equivalence circuit, Rs(RPtQPt)(RrQµ)(RDoQDo), was proposed to describe the main features of impedance characteristics for studied DSCs. For the fresh-prepared DSCs with various iodine concentrations, all the RPt, Rr and RDo are increased with decreasing of iodine concentration and cell performance features, such as short-circuit current, open-circuit potential and energy conversion efficiency. The cell performance degradation under light and thermal aging was reflected by increasing of Rr and RDo which was clearly shown from impedance data analysis. There was observed a correlation between the sharp rise of RDo and the decrease of ISC. It was suggested that one of the reasons for DSC decays is the decrease of iodine content in the electrolyte after long-term light and thermal stressing tests.
The Substituent Effect on the Reduction Potentials of Heterocycle-fused [60]fullerene Derivatives
Authors: Numata Youhei , Kawashima Junichi , Tajima Yusuke
Published: May 2009

Benzo furano[2´,3´:1,2][60]fullerene derivatives were derived from the reaction of fullerene monoepoxide C60O with phenol compounds in the presence of BF3•OEt2 as a Lewis acid catalyst in a chlorobenzene solution. We prepared various indolino[60]fullerene- and benzo furano[60]fullerene derivatives comprising either an electron-donating or a withdrawing substituent on the indoline and benzo furan moieties. The reduction potentials of these compounds depended on the type of substituent effect; first, linear correlations existed between the substituent constants and their first reduction potentials, and second, the first reduction potentials remarkable reduced due to the influence of the 4´-MeO groups.
Pancreatic Fistula Following Pancreaticoduodenectomy: Clinical Predictors and Patient Outcomes
Authors: Schmidt C. Max , Choi Jennifer , Powell Emilie S. , Yiannoutsos Constantin T. , Zyromski Nicholas J. , Nakeeb Attila , Pitt Henry A. , Wiebke Eric A. , Madura James A. , Lillemoe Keith D.
Published: May 2009

Pancreatic fistula continues to be a common complication following PD. This study seeks to identify clinical factors which may predict pancreatic fistula (PF) and evaluate the effect of PF on outcomes following pancreaticoduodenectomy (PD). We performed a retrospective analysis of a clinical database at an academic tertiary care hospital with a high volume of pancreatic surgery. Five hundred ten consecutive patients underwent PD, and PF occurred in 46 patients (9%). Perioperative mortality of patients with PF was 0%. Forty-five of 46 PF (98%) closed without reoperation with a mean time to closure of 34 days. Patients who developed PF showed a higher incidence of wound infection, intra-abdominal abscess, need for reoperation, and hospital length of stay. Multivariate analysis demonstrated an invaginated pancreatic anastomosis and closed suction intraperitoneal drainage were associated with PF whereas a diagnosis of chronic pancreatitis and endoscopic stenting conferred protection. Development of PF following PD in this series was predicted by gender, preoperative stenting, pancreatic anastomotic technique, and pancreas pathology. Outcomes in patients with PF are remarkable for a higher rate of septic complications, longer hospital stays, but in this study, no increased mortality.
Refining the 22q11.2 deletion breakpoints in DiGeorge syndrome by aCGH
Authors: Bittel D.C. , Yu S. , Newkirk H. , Kibiryeva N. , Holt III A. , Butler M.G. , Cooley L.D.
Published: May 2009

Hemizygous deletions of the chromosome 22q11.2 region result in the 22q11.2 deletion syndrome also referred to as DiGeorge, Velocardiofacial or Shprintzen syndromes. The phenotype is variable but commonly includes conotruncal cardiac defects, palatal abnormalities, learning and behavioral problems, immune deficiency, and facial anomalies. Four distinct highly homologous blocks of low copy number repeat sequences (LCRs) flank the deletion region. Mispairing of LCRs during meiosis with unequal meiotic exchange is assumed to cause the recurrent and consistent deletions. The proximal LCR is reportedly located at 22q11.2 from 17.037 to 17.083 Mb while the distal LCR is located from 19.835 to 19.880 Mb. Although the chromosome breakpoints are thought to localize to the LCRs, the positions of the breakpoints have been investigated in only a few individuals. Therefore, we used high resolution oligonucleotide-based 244K microarray comparative genomic hybridization (aCGH) to resolve the breakpoints in a cohort of 20 subjects with known 22q11.2 deletions. We also investigated copy number variation (CNV) in the rest of the genome. The 22q11.2 breaks occurred on either side of the LCR in our subjects, although more commonly on the distal side of the reported proximal LCR. The proximal breakpoints in our subjects spanned the region from 17.036 to 17.398 Mb. This region includes the genes DGCR6 (DiGeorge syndrome critical region protein 6) and PRODH (proline dehydrogenase 1), along with three open reading frames that may encode proteins of unknown function. The distal breakpoints spanned the region from 19.788 to 20.122 Mb. This region includes the genes GGT2 (gamma-glutamyltransferase-like protein 2), HIC2 (hypermethylated in cancer 2), and multiple transcripts of unknown function. The genes in these two breakpoint regions are variably hemizygous depending on the location of the breakpoints. Our 20 subjects had 254 CNVs throughout the genome, 94 duplications and 160 deletions, ranging in size from 1 kb to 2.4 Mb. The presence or absence of genes at the breakpoints depending on the size of the deletion plus variation in the rest of the genome due to CNVs likely contribute to the variable phenotype associated with the 22q11.2 deletion or DiGeorge syndrome.
Repetitive DNA probe linked to sex chromosomes in hybrids between Neotropical fish Leporinus macrocephalus and Leporinus elongatus (Characiformes, Anostomidae)
Authors: Hashimoto D.T. , Parise-Maltempi P.P. , Laudicina A. , Bortolozzi J. , Senhorini J.A. , Foresti F. , Porto-Foresti F.
Published: May 2009

Interspecific hybrids of fish can offer important advances in the zootechnical exploration of this animal group. However, hybrids can pose serious biological risks to the environment and natural populations, making genetic characterization and monitoring of hybrids produced in fish culture important concerns. In the present study, individuals of the hybrid ‘Piaupara’ were characterized by fluorescence in situ hybridization (FISH) using sex-specific probes to differentiate the respective parental contributions from female Leporinus macrocephalus (Piauçu) and male Leporinus elongatus (Piapara). The application of this technique demonstrated a difference in hybridization patterns between males and females of L. elongatus and L. macrocephalus, mainly due to the fact that the NOR-bearing chromosomes of L. elongatus contain some homology with the probe. This allowed us to detect a clear sex-specific distinction of the hybrid ‘Piaupara’, demonstrating that this technique is well-suited for the characterization of these hybrids. Moreover, this technique offers an important methodological advance for the study of diverse sex chromosome systems of Leporinus, supplying valuable information about the origin and establishment of a recently described sexual system in this genus.
Pregnant Women after Physical and Sexual Abuse in Germany
Authors: Jundt Katharina , Haertl Kristin , Knobbe Angelika , Kaestner Ralph , Friese Klaus , Peschers Ursula M.
Published: May 2009

Background/Aims: The aim of our study was to evaluate the prevalence of abuse among pregnant women in Germany attending our antenatal outpatient clinic and to observe whether a history of abuse had consequences for women’s feelings about their pregnancy. Methods: 455 women between the 35th and 42nd weeks of gestational age were included and were asked to fill out an anonymous questionnaire concerning their pregnancy, their actual psychological state, and their history of physical/sexual abuse. 600 questionnaires were distributed (return rate 75.8%), 70 women (10.4%) were excluded because of male companionship to ensure their safety in case that they were currently in an abusive relationship with the attending man. Results: 88 women (19.3%) reported a history of sexual and/or physical abuse. Pregnant women after physical and/or sexual abuse significantly more frequently associate negative feelings with their pregnancy than nonabused women. The Hospital Anxiety Depression Scale (HADS) and the SCL-K-9 demonstrated significantly more negative feelings of depression and anxiety, strain, loneliness and less expectation of happiness for their future in abused women. Conclusion: Physical and sexual abuse are relevant problems among women in obstetric care that may complicate their pregnancies and make them feel more depressive.
Precision and Accuracy of Stereotactic Targeting in Patients Undergoing Repeat Stereotactic Surgery
Authors: Zacest Andrew , Berk Caglar , Burchiel Kim J.
Published: May 2009

Background/Aims: Accurate and precise stereotactic targeting is crucial in obtaining the best outcome for patients undergoing functional neurosurgical procedures. Methods: We calculated the precision and accuracy of stereotactic targeting in 20 consecutive patients who underwent repeat stereotactic surgery from January 2001 to December 2007 at one institution. Two sets of target coordinates were calculated for each patient undergoing repeat surgery from their magnetic resonance images and using Stealth Station and Framelink software. The 1st target coordinate was the initial stereotactic lesion or known functional electrode contact and the 2nd was the computer-calculated coordinate of the selected functional target (ventrointermediate, globus pallidus internus, or subthalamic nucleus ) for the repeat surgery. Results: All patients had a good functional outcome following the initial surgery. Mean differences between coordinates (for all stereotactic targets combined) were 1.35, 1.18 and 1.28 mm for X, Y and Z, respectively. The absolute difference between target points was 2.77 mm. Conclusion: This demonstrates a high level of precision and accuracy with contemporary frame-based neuronavigation and stereotactic techniques. Similar data can be easily collected and analyzed for auditing purposes at any neurosurgical center to ensure optimal outcome for patients.
Long-Term Outcome of Endovascular Treatment versus Medical Care for Carotid Artery Stenosis in Patients Not Suitable for Surgery and Randomised in the Carotid and Vertebral Artery Transluminal Angioplasty Study (CAVATAS)
Authors: Ederle Jörg , Featherstone Roland L. , Brown Martin M.
Published: May 2009

Background: Optimal treatment of carotid stenosis in patients not suitable for surgery is unclear. The Carotid and Vertebral Artery Transluminal Angioplasty study contained a trial comparing medical and endovascular treatment in patients not suitable for surgery. Methods: Forty patients were randomised to medical or endovascular treatment in equal numbers, and patients were followed up for up to 10 years. The primary outcome measure was defined as stroke or death during follow-up, analysed by intention-to-treat. Secondary analyses included disabling stroke, death, any stroke, any stroke or transient ischemic attack (TIA), all during follow-up. Findings: Baseline characteristics were similar. The risk of stroke, retinal infarction or death within 30 days of endovascular treatment was 5% (95% CI: 0.1–24.9%). By the study end, >50% of patients had suffered a recurrent TIA, stroke or died. One third of events were non-stroke deaths. Overall, there was no significant difference between medical and endovascular treatment in the primary outcome rate of stroke or death after randomisation (hazard ratio: 0.98, 95% CI: 0.39–2.48) or the rate of any stroke or TIA (hazard ratio: 1.43, 95% CI: 0.54–3.75). Interpretation: We failed to show superiority of endovascular treatment above medical care alone for carotid stenosis in a very small group of patients not suitable for surgical treatment. However, the trial randomised only 40 patients, and was therefore severely underpowered to detect clinically relevant treatment differences. Ongoing trials of carotid stenting will need to demonstrate improved safety and efficacy before endovascular treatment should enter routine practice.
Preadmission Use of Warfarin Improves Short-Term Outcome in Patients with Acute Cerebral Infarction
Authors: Naess Halvor , Brogger Jan , Waje-Andreassen Ulrike , Idicula Titto T. , Thomassen Lars
Published: May 2009

Background: We hypothesized that patients with cerebral infarction on preadmission warfarin have less severe neurological deficits on admittance, less severe neurological deficits 1 week after the onset of cerebral infarction and a larger improvement as to neurological deficits within 1 week of acute cerebral infarction. Methods: All patients with cerebral infarction who did not receive thrombolytic treatment were included. Preadmission use of warfarin was registered. The National Institute of Health Stroke Scale (NIHSS) score was obtained on admittance and 7 days after stroke onset. Results: In total, 42 patients (8.1%) used warfarin at the time of stroke onset. The mean NIHSS score on admittance was 6.9 among the patients on warfarin and 5.2 among those without warfarin (p = 0.10). The 1-week improvement in the NIHSS score was 3.5 among the patients on warfarin and 0.8 among the participants without warfarin (p < 0.001). Linear regression showed that a low NIHSS score on day 7 was independently associated with a low NIHSS score on admittance (p < 0.001), low age (p = 0.002) and preadmission use of warfarin (p < 0.001). Conclusion: Preadmission warfarin was not associated with less severe neurological deficits on admittance. However, it was related to both less severe neurological deficits 1 week after the onset of cerebral infarction and larger improvement as to neurological deficits within 1 week of acute cerebral infarction.
Effect of Ascitic Media Formed by Glycerin on the Prevention of Peritoneal Adhesions
Authors: Aksoy F. , Vatansev C. , Tekin A. , Pamukcu A. , Küçükkartallar T. , Yılmaz H. , Vatansev H. , Esen H. , Aksoy N.
Published: May 2009

Aim: We aimed to investigate whether or not artificial ascites media formed using glycerin are effective in the prevention of intraperitoneal adhesions. Methods: Thirty-six Wistar albino male rats were used in the study. The rats were divided into 3 groups as follows. Group I: control group; group II (isotonic group): 3 ml of 0.9% NaCl was injected into the peritoneal cavity, and group III (glycerin group): 0.5 ml of liquid glycerin and 3 ml of 0.9% NaCl was injected into the peritoneal cavity. Results: There were serious adhesions in the control group. Adhesion rates were lower in the isotonic group compared with the control group, but the difference was not statistically significant (p > 0.05). When adhesion rates of the glycerin group were compared with the control and isotonic groups, significant differences were found, especially between the glycerin and control groups (p < 0.05). Conclusions: According to the results of our study, the use of isotonic solution and liquid glycerin decreases postoperative adhesions. We suggest that glycerin was more effective as it has the chemical ability to draw water to its media. As such, the formation of adhesions may be decreased by increasing the amount of physiological liquid inside the abdomen.