bluuebunny/crossref_metadata_2025 huggingface dataset:
Band Engineering of Rutile TiO2 by Cobalt Doping in Ru/Rutile-TiO2/Ru Capacitor aiming 40-nm DRAM and Beyond
Authors: Tonomura Osamu , Sekiguchi Tomoko , Inada Naomi , Hamada Tomoyuki , Miki Hiroshi , Torii Kazuyoshi
Published: May 2009

A Feasible fabrication process of Ru/rutile-Co-doped TiO2/Ru capacitor for 40-nm DRAM and beyond is developed. As-deposited Ru lower electrode is found out to crystallize Co-doped TiO2 overlayer into rutile having relative permittivity beyond 90 owing to lattice matching. Furthermore, we predicted doping of element having small ionic radius, such as Co, increase Schottky barrier, leading to decrease in leakage current. Temperature dependence of leakage current of RIR-Co-doped-TiO2 capacitor and band structure analysis with X-ray photoelectron spectroscopy shows that leakage current is determined by balancing between thermionic current and tunneling current through Schottky barrier. By doping of Co, the thermionic current decreases, whereas the tunneling current increases. With calculation using theoretical dependence of amount of doped element on leakage current, optimum percentage of Co is estimated as 0.3-0.6 % to achieve a sufficiently low leakage-current. This technology opens possibility to utilize 40-nm DRAM and beyond.
Multiprincipal-Element AlCrTaTiZr-Nitride Nanocomposite Film of Extremely High Thermal Stability as Diffusion Barrier for Cu Metallization
Authors: Chen Dao-Sheng , Chen Ming-Ku , Chang Shou-Yi
Published: May 2009

To inhibit Cu diffusion in interconnects, an effective diffusion barrier of high thermal stability is strongly demanded. Thus in this study, a nitride nanocomposite film of equimolar five-element high-entropy alloy, (AlCrTaTiZr)N, was developed and deposited by reactive sputtering. Thermal stability of the (AlCrTaTiZr)N film and its barrier performance to the interdiffusion of Si and Cu were investigated under thermal annealing at 700 to 900oC. The (AlCrTaTiZr)N, constructed of mixed crystalline and amorphous nanocomposite structure, was found to remain thermally stable at an extremely high temperature of 900oC. Neither interdiffusion between Si and Cu through the (AlCrTaTiZr)N layer nor formation of any silicides occurred. Severe lattice distortions caused by the incorporation of multiprincipal elements and the nanocomposite structure of nanocrystallites surrounded by an amorphous matrix without the existence of grain boundaries were expected as the dominant factors for the high thermal stability and superior diffusion resistance of the (AlCrTaTiZr)N film.
Effect of NH3/He Plasma Treatment on Electromigration Behavior and Electrical Reliability of Copper Interconnects
Authors: Chang Shou-Yi , Lin Fong-Jie , Lin Chia-Feng
Published: May 2009

Electromigration reliability tests of Cu interconnect structures with or without an NH3/He plasma treatment have been performed in this study at 400oC under a high current density of 8 MA/cm2 to clarify the effect of plasma treatment on the interface structure, early-stage electromigration behavior and electrical reliability of interconnects. From cumulative failure probabilities, small shape factors and large median time to failure were obtained for the interconnects with the plasma treatment, indicating an improved electromigration resistance. The oxide layer on Cu surface was removed, and an alternative CuSiN interlayer with a lattice spacing of 0.195 nm formed at the Cu/SiCN interface, enhancing interface adhesion and reducing the diffusion paths of Cu atoms. Therefore, voids nucleated inside the Cu wires, rather than at the interface. The change in the Cu/SiCN interface structure varied the early-stage electromigration-induced voiding behavior and effectively improved the electrical reliability of the Cu interconnect structures.
Potential-pH Diagrams of Copper for the Planarization Slurries with Different Complexing Agents
Authors: Aksu Serdar
Published: May 2009

Planarization processes such as chemical mechanical planarization (CMP) and electrochemical mechanical planarization (ECMP) are typically carried out with slurries containing complexing agents as one of the principal chemical components. In such slurries, complexing agents enhance the solubility of copper and increase the dissolution rate of the abraded material, promoting higher copper planarization rates. The nature of the complexing agents used in the slurry, along with slurry pH and redox potential are among the key factors controlling the dissolution and passivation behavior of copper, and thereby governing the dynamic copper removal and planarization rates during the CMP and ECMP processes. In this paper, potential-pH diagrams of copper in aqueous systems containing a number of complexing agents including glutaric acid, maleic acid, α-alanine and α-aminobutyric acid are presented. The predominance regions of copper complexes under different copper and ligand activities and their implications on copper removal during planarization processes are discussed.
Reduction of Scratch on Brush Scrubbing in Post CMP Cleaning by Analyzing Contact Kinetics on Ultra Low-k Dielectric
Authors: Gu Xun , Nemoto Takaneo , Teramoto Akinobu , Ito Takashi , Sugawa Shigetoshi , Ohmi Tadahiro
Published: May 2009

Damage reduction during planarization is strongly required to avoid scratch generation leading to yield loss in an integrated circuit fabrication especially after implementation of ultra low-k dielectrics in Cu damascene structure. By analyzing contact characteristic on the advanced non-porous ultra low-k dielectric, fluorocarbon film, brush scrubbing at high rotation rate and low down pressure is proposed to satisfy both particle removal efficiency and scratch reduction in post CMP cleaning. Shear force increases with increasing in brush rotation rate because of enlargement of pressured area which is generated by fluid flow. Enhancement of contribution of fluid flow by increasing brush rotation rate with lowering down force to particle removable efficiency can be direction for future low-k compatible process.
Extreme Nano-structure Control by Sputtering for the High Density Perpendicular Recording Media and Head
Authors: Takahashi Migaku , Tsunoda Masakiyo , Saito Shin
Published: May 2009

In order to open a way to realize ultra high density hard disk (HD) drives with fast operation speed utilizing a spin nano-technology, precisely controlled fabrication technology with nano-scale for head and media according to the required properties is essential from material, processes, and physical view point. In the present paper, correlation between process parameter of ultra clean (UC) dry-process proposed by us and structure and physical property for ferro/antiferro interface, magnetic tunnel junctions and perpendicular magnetic recording media will be widely discussed.
Annealing-Induced Solid-Phase Epitaxy at Interfaces between CoFeB Layers and MgO Barrier-Layer in CoFeB/MgO/CoFeB Magnetic Tunnel Junctions and Their Magnetic Properties
Authors: Kitamoto Yoshitaka , Takeuchi Takashi , Tsunekawa Koji , Choi Young-suk , Nagamine Yoshinori , Djayaprawira David D.
Published: May 2009

The present paper describes influences of annealing conditions and chemical composition on grain-to-grain epitaxy, which is induced by annealing after sputter-deposition, in MgO based magnetic tunnel junctions (MTJs) with CoFeB ferromagnetic layers. Annealing-induced crystallization in the amorphous CoFeB layer (at as-deposited state) at the interface with the MgO layer in CoFeB/MgO/CoFeB MTJs is investigated by electron microscopy. Annealing conditions such as temperature and time as well as the chemical composition in the CoFeB layers strongly influence magnetoresistance (MR) ratio. Excess annealing (temperature and time) causes the break-down of synthetic antiferromagnet (SAF) structure in MTJs for practical applications, resulting in the decrease of MR ratio. Fe-rich CoFeB is more suitable to obtain better grain-to-grain epitaxy and higher MR ratio in view of lattice mismatch with the MgO layer. The annealing conditions and chemical composition are optimized to exhibit the highest MR ratio with keeping SAF structure.
Critical Parameters of Solution Design for Electrodeposition of 2.4 T CoFe Alloys
Authors: Brankovic Stanko R. , George Jinnie , Bae Sang , Litvinov Dmitri
Published: May 2009

The electrodeposition of soft, high magnetic moment alloys has become the critical fabrication step in manufacturing of magnetic recording heads. The need for ultimately high magnetic moment alloys (2.4 T CoFe) and the electrodeposition process capable of delivering magnetic structures with dimension in the range of several tens of nanometers are the new tasks that have to be addressed if the future magnetic recording devices will use the electrodeposited alloys for writing pole application. This complex challenge could be successfully achieved by fully considering the conditions at the electrochemical interface for additive adsorption and incorporation, iron hydroxide formation and incorporation, and by careful design of the bath chemistry and deposition parameters that would yield the high moment alloys with the optimum magnetic properties. In this manuscript, some of the key aspects of successful electrodeposition of 2.4 T CoFe alloys are discussed with experimental results and theoretical foundations indicating future direction for development of electrodeposited high moment alloys and nanostructures.
Process of CoPt Alloys Electrodeposition for MEMS/NEMS Applications
Authors: Berkh Olga , Shacham-Diamand Yosi , Gileadi Eliezer
Published: May 2009

CoPt electrodeposited alloys present high interest for application in MEMS/NEMS, because of their interesting magnetic characteristics. Integration of CoPt films into MEMS/NEMS devices is hampered by instability of the deposition process (change of deposition current efficiency and CoPt alloy characteristics with total charge passed through electrolyte in previous runs). The deposition process of CoPt alloys from ammonium citrate electrolyte containing the diammine-dinitrito-platinum (II) complex as the source of Pt is considered in terms of its stability and reliability. Removal of ligands by thermal treatment of Pt complex allows the elimination of the total charge effect on deposition current efficiency. The role of ammonia loss during pretreatment and operation is discussed.
Electrodeposition of Co, Sm and Co-Sm Thin Layers
Authors: Ispas Adriana , Buschbeck Mihaela , Pitula Slawomir , Mudring Anja , Uhlemann Margitta , Bund Andreas , Endres Frank
Published: May 2009

Electrodeposition of thin layers with thicknesses between 40nm and 700nm of cobalt, samarium and cobalt-samarium was carried out in the ionic liquid 1-butyl- 1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide, [P1,4]-TFSA, The precursors for electrodeposition were tailor-made Co(TFSA)2 and Sm(TFSA)3 metal salts. We could show that by increasing the temperature the quality of the deposited layers improved significantly. Moreover, the deposition potential influences strongly the morphology of the deposits.
DC Aqueous Electrodeposition of Sm-Co Permanent Magnets
Authors: Wei J.C. , Schwartz Morton , Nobe Ken
Published: May 2009

DC electrodeposition of permanent magnets has been studied using parallel electrodes in aqueous solutions of Sm, Co and glycine. It has been shown that reproducible metallic SmCo alloy electrodeposits of high Sm content sufficient to achieve the intermetallic compounds, SmCo5 and Sm2Co17, have been obtained. These alloys after appropriate heat treatment can provide inexpensive nano- and micron-size as well as electroform materials with high performance permanent magnetic properties. A temperature of 60oC is optimum for producing deposits of at least 32 at % Sm or higher. Some desirable properties can be obtained by the use of certain specific supporting electrolytes. Magnetic hysteresis loops of SmCo deposits at both 25 and 60oC show that as Sm content increases deposits are transformed from anisotropic to isotropic magnetics. Magnetic properties of electrodeposits are comparable to sputtered deposits before heat treatment.
Effects of Organic Additives on the Residual Stress of Ni and Ni Alloys Electrodeposited from the Sulfamate Bath
Authors: Kim Hyoung Chan , Kim Young Seok , Lee Sang Joon , Lee Ju Dong , Lee Man Sig , Kim Yang-Do
Published: May 2009

The residual stress in the deposits of Ni and Ni alloys was estimated from the deflection of one side deposited test strips (Specialty testing & Development Co.). 2,6-Naphthalene- disodiumsulfate (2,6-NDS) and 1,3,6-Naphthalenetrisodiumsulfate (1,3,6-NTS) were adopted instead of saccharin and , among the three additives, the lowest residual stress was obtained with 1,3,6-NTS. However, to adjust compressive stress, certain quantity of amine additives such as MEA (Monoethanolamine), DEA (Diethanolamine) and TEA(Triethanolamine) were added stepwise to the bath containing 1,3,6-NTS while electrodepositon proceeded. Effects on reducing residual stress was in order of MEA<DEA<TEA, which seemed to have a connection with lone pair and basicity of the nitrogen attached to the amine additives. The highest Vickers hardness was attained with the Ni-Co alloy deposit from the Ni-Co(Ni:80g/L-Co:4.8g/L) bath and the cobalt content of the deposit was 28.4%(wt./wt.). Properties and cobalt content of the deposits were evaluated and analyzed with SEM, XRD, EDS and ICP respectively.
Electrodeposition of Magnetic Nickel Matrix Nanocomposites
Authors: Bund Andreas , Gräf Christian , Thiemig Denny , Kubeil Clemens
Published: May 2009

We will discuss recent results from our labs on the electrocodeposition of magnetic nanoparticles in a nickel matrix. To enhance the particle content of the layers we applied a magnetic field during the electroplating process. The role of the orientation of the magnetic field on the particle content of the layers will be discussed.
Design of a Multiple-Electrode Magnetic-Alloy Plating Cell Using Numerical Modeling
Authors: McHugh Paul R. , Wilson Gregory , Erickson Dave , Woodruff Daniel
Published: May 2009

Uniformity specifications for modern magnetic-alloy electroplating processes are stringent, and become more challenging as substrate sizes increase and product is driven closer to the substrate edge. Tight process specifications on uniformity and composition require electric field control and uniform electrolyte agitation. The latter is difficult because the substrate must maintain a fixed orientation with respect to a magnetic-field during processing. A new multiple-electrode, high-agitation cell for electroplating magnetic alloys is discussed. Mass-transfer simulations are used to design a multi-blade, oscillating structure that provides a spatially-uniform and controllable agitation level, which enables modification of alloy composition and/or deposition rate. Electric-field simulations are used to design a chamber in which the electric field can adapt to different electrochemical processes including various bath conductivities, substrate resistances, and applied currents. A remote placement of the thief electrode is used to avoid particle contamination on the substrate and to reduce thief maintenance.
Development of IT-SOFC Based on Lanthanum Gallate Electrolyte
Authors: Nishi Junya , Inagaki Toru , Nishiwaki Futoshi , Kano Jiro , Onishi Yasutaka , Yamasaki Satoru , Hirata Katsuya , Sato Motoki , Akbay Taner , Eto Hiroyuki
Published: May 2009

The Kansai Electric Power Company, Inc. and Mitsubishi Materials Corporation started a joint research project for developing intermediate temperature (600{degree sign}C to 800{degree sign}C) solid oxide fuel cells (IT-SOFC) in 2001. High performance disk-type cells with lanthanum gallate-based electrolyte and a seal-less cell-stack design enable high efficiency operation at temperatures below 800{degree sign}C. The development of 10 kW-class CHP system under a project supported by NEDO (New Energy and Industrial Technology Development Organization) was started in FY2004. In 2007, the performance test of the 10 kW-class system using town gas as fuel has been undertaken. In this test, the electrical efficiency of 41%HHV on AC power output of 10 kW and the overall efficiency of 82%HHV by recovering 60åC hot water have been achieved. And the voltage degradation rate per 1,000 hours was 1.08% after 3,000 hours operation has been observed during the field test of the 10 kW-class system. Furthermore, after making some refinements to enhance the performance of 10 kW-class module, the second long-term stability test for 3,000 hours were carried out in 2008. Efforts to enhance cell and module durability have been made with 1 kW-class modules operated for 5,000 hours, and with the cell-stack units operated for 15,000 hours. The voltage degradation rates per 1,000 hours were 0.51 % for the 1 kW-class modules, and 0.23 - 0.48% for the cell-stack units.
Low Temperature SOFC Cathode Layer Deposited by Reactive Spray Deposition Technology (RSDT)
Authors: Maric Radenka , Neagu Roberto , Zhang Xinge , Roller Justin
Published: May 2009

Present work presents the results obtained by using a direct deposition technique to make SOFC cathode materials that either significantly reduce or eliminate the need for sintering. A reference composite cathode made of 75 wt.% Sm0.5Sr0.5CoO3 (SSC) and 25 wt.% Sm0.2Ce0.8O1.9 (SDC) has been applied on a cermet supported thin SDC electrolyte cell. Cell peak power performance was measured to be 0.49 W cm−2 operating at 600 {degree sign}C after firing at 1050 {degree sign}C. The measured total electrode polarization Rp(a + c) was 0.102 Ω cm2 at 600 {degree sign}C. In this study a thin (~5 μm) SSC cathode has been applied by Reactive Spray Deposition Technology (RSDT) and the total polarization was reduced to 0.079 Ω cm2, indicating over 20% reduction of losses compared to the traditional cathode processing route
Advanced Anode-supported Micro-tubular SOFC Development
Authors: Zuo Chendong , Du Yanhai , Finnerty Caine , Cheekatamarla Praveen , Dong Jian , Jiang Juan , Huang Wenhua , Lankin Michael , Sharp Rebecca
Published: May 2009

Micro-tubular SOFCs with rapid start-up and great thermal-shock resistance for portable applications are being developed at NanoDynamics Energy, Inc. In this paper, we present the single-cell that can provide over 10 W power, while being able to withstand very rapid temperature changes (up to 980 oC/min). The cell power did not lag with fast heating rates and the single-cell exhibited a 1.3% power increase after 200 thermal cycles. Due to the excellent thermal-shock resistance, the cell can provide full power within two minutes of operation.
CFD Modeling of Planar, Solid Oxide Fuel Cells at the Institute of Nuclear Energy Research, Taiwan using STAR-CD
Authors: Ippolito James , Huang I-Ming , Recknagle Kurtis
Published: May 2009

Presented is a key paper in the development of effective SOFC models. The paper employed a fully three-dimensional, computational fluid dynamics (CFD) STAR-CD model on a planar, five-cell, solid oxide fuel cell. Geometry and experimental data were provided by the Institute of Nuclear Energy Research (INER), Taiwan. The objective of this study was to validate the CFD results based on measurements taken at INER. The model was validated experimentally and used to predict current density distribution, fuel and oxidant utilization, flow and temperature distribution, and heat transfer information.
Multi-Scale Physical Modeling of Fuel Cells, From Sub-System to Stack
Authors: Montaland Patrice
Published: May 2009

A methodology allowing the design and the optimization of fuel cells systems has been developed thanks to a comprehensive modeling environment. This solution enables to size components of a system, optimize architectures and geometries, develop and test control strategies, test different gas mixture and material solutions, predict produced voltage and transient evolution of temperatures, pressures, mass flow rates and gas mass fraction everywhere in the system. The solution uses physical modeling, based on energy exchanges approach between basic elements which can be assembled to represent any configuration of a complete fuel cell system. It allows to create a predictive model of complete system, and to represent both static and dynamic behavior. It enables the simulation of the stack as well as global systems (coupling between stack, cooling system, feeding system, control system, electrical system...).
Feasibility of SOFC Operation with Bio-Methane and Bio-Hydrogen from Anaerobic Digestion
Authors: Leone Pierluigi , Lanzini Andrea , Santarelli Massimo , Zitella Paola , Calì Quaglia Michele
Published: May 2009

High efficiency and valuable energy distributed generation could be achieved with the coupling of solid oxide fuel cells and biomass processing technologies. This coupling would take advantage of the high operating temperature of the fuel cell and the efficient recovery of its waste high temperature irreversible heat for processes' integration (i.e. thermal integration) and system's performance enhancement. However, different biomass processing technologies lead to bio-fuels of different behaviour in terms of degradation phenomena at the anode side, fuel cell system thermal balance and impact on the performance of the overall system. This paper investigates the utilization of different biogases from anaerobic digestion in solid oxide fuel cells. Two different fermentation paths will be investigated. A first path leads to the production of bio-methane mixtures characterized by the presence of CH4/CO2 (typical 60/40 vol%); a second and innovative path leads to the production of bio-hydrogen mixtures which consist of H2/CO2 (typical 50/50 vol%).
Solid Oxide Fuel Cells: Development Activities, Trends and Technological Challenges
Authors: Minh Nguyen Q. , Singhal C. , Williams Mark
Published: May 2009

Development efforts in solid oxide fuel cells (SOFCs) for power generation have expanded significantly in the past twenty years. At present, SOFC is being studied/developed in at least thirty countries worldwide. The widening interest in this technology arises from the continuing need to develop cleaner and more efficient power systems and the attractive attributes of this type of fuel cell (multi-fuel capability, all-solid state construction, and high operating temperature) that permit appropriate cell designs/system configurations and efficient operation on a variety of practical fuels for a broad range of applications. This paper surveys worldwide activities, examines R&D trends, and discusses key technological challenges in the development of SOFC for power generation.
Recent Advances in Hydrogen and Fuel Cell Technology
Authors: Garland Nancy , Milliken JoAnn , Satyapal Sunita , Munetz Jonathan , McMurphy Kevin
Published: May 2009

Research supported by the Department of Energy's Hydrogen Program has yielded substantial progress in hydrogen production, delivery, storage, and fuel cell technologies. The Program has met its hydrogen cost target of $3/gas gallon equivalent (gge) for hydrogen produced by distributed natural gas reforming, down from $5/gge in 2005. While some current fuel cell vehicles have a range exceeding 300 miles, the Program have identified promising materials-based technologies to achieve this range across all vehicle platforms without compromising passenger or cargo space, performance, or cost. In the area of fuel cells, the projected cost for a mass-produced, polymer electrolyte membrane (PEM), automotive fuel cell system has been reduced to $73/kW from $275/kW in 2002. Program-funded research has led to improvements in conductivity for high-temperature PEM fuel cell membranes at low relative humidity, and to the development of a membrane electrode assembly (MEA) with over 7,300-hour durability.
In Situ PEM Fuel Cell Water Measurements
Authors: Borup Rod L. , Mukundan Rangachary , Davey John , Spendelowa Jacob , Hussey Daniel S. , Jacobson David L. , Arif Muhammad
Published: May 2009

Efficient PEM (Polymer Electrolyte Membrane) fuel cell performance requires effective water management. To achieve a deeper understanding of water transport and performance issues associated with water management, we have conducted in situ water examinations to help understand the effects of components and operations. High Frequency Resistance (HFR), AC Impedance and Neutron imaging were used to measure water content in operating fuel cells. High resolution neutron radiography was used to image fuel cells during a variety of conditions. The effect of specific operating conditions, including flow direction (co-flow or counter-flow) was examined. Counter-flow operation was found to result in higher water content than co-flow operation, which correlates to lower membrane resistivity. A variety of cells were used to quantify the membrane water in situ during exposure to saturated gases, during fuel cell operation, and during hydrogen pump operation. The quantitative results show lower membrane water content than previous results suggested.
Effect of Freezing Conditions on PEM-FC Components
Authors: Gavello Gianluigi , Ambrosio Elisa P. , Icardi Ugo A. , Specchia Stefania , Francia Carlotta , Penazzi Nerino , Specchia Vito
Published: May 2009

For mobile applications, performance of polymer electrolyte membrane fuel cells (PEM-FCs) should be maintained with being exposed to subzero temperatures in winter time. To simulate such a situation, a single cell PEM-FC was operated at 70{degree sign}C, stopped, kept at -10{degree sign}C for 8 h, and heated to 80{degree sign}C for the next operation. The cell was unable to work. The degradation was attributed to freezing of water present inside the MEA, produced during operation, and remained in the PEMFC after the operation. To prevent the performance degradation, water was removed from the PEM-FC by supplying dry N2 to the PEM-FC before the cell temperature fell down to -10{degree sign}C. Several freezing/thawing cycles were operated to study the PEM-FC performance degradation. Effects of water freezing in the PEM-FC on the electrode structure were examined by SEM analysis.
Humidity Standard of Compressed Oxygen for Future Generation PEM Fuel Cells
Authors: Huang Peter H.
Published: May 2009

Compressed oxygen is one of the most important needs for future generation PEM fuel cells. For the measurement and control as well as the design of humidification equipment, knowledge of the equilibrium water content of oxygen as a function of temperature and pressure is desirable. A simple presentation in chart form is usually adequate for most fuel cell applications and such a chart has been prepared based on the information on the water vapor content of a oxygen-water mixture. Absolute humidity of grams of water vapor per kilogram of dry oxygen is determined as a function of pressure up to 20 atmospheric pressures for various dew-point temperatures in the range of 0 {degree sign}C to 100 {degree sign}C. The maximum expanded uncertainty at a 95 percent confidence level is determined to be 2 percent of the value for this temperature range.
Three-Dimensional Simulation of Liquid Water Distribution in a Single PEMFC with Interdigitated Flow Channels
Authors: Le Anh D. , Zhou B.
Published: May 2009

A powerful approach to investigate two-phase interactions and liquid interface tracking has been developed in a 3-D proton exchange membrane fuel cell (PEMFC). By introducing Volume-of-Fluid (VOF) algorithm combined with detail fluid flow, heat and mass transport and electrochemistry processes, the real-time water liquid motion in the channels and accumulation in the porous media can be described at different time instants during operation. The simulation shows that the presence of liquid water in the channels causes a significant increase of pressure drop and uneven distribution of flow field in the cell. Moreover, liquid water located in some regions of the gas diffusion layers (GDLs) hinders the mass transport of reactant gases and prevents the reactions taking place in the catalyst layers, resulting in a degradation of current density and then severely affects the PEMFC performance.
Investigation on Denaturing Agents for Use with Ethanol in Direct Ethanol Fuel Cells (DEFC)
Authors: Cremers Carsten , Bayer Domnik , Kintzel Birgit , Joos Martin , Krausa Michael , Martin Dierk , Bernard Jörg
Published: May 2009

An ethanol derivative and fusel oil were investigated regarding their possible use as denaturing agents for ethanol for DEFC in 0.5 M sulphuric acid and 0.1 M potassium hydroxide solution at platinum by means of cyclic voltammetry and differential electrochemical mass spectroscopy. It was found that fusel oil is not suitable as denaturing agent for DEFC due to strong adsorption to platinum surfaces and the hindrance of the ethanol conversion. On the other hand, the investigated ethanol derivative does not hinder the ethanol conversion as much and therefore seems to be a promising candidate for a denaturing agent to use with ethanol in DEFC.
Development of the Hydrogen Storage System for the Deep and Long Range Underwater Vehicle Powered by Fuel Cell
Authors: Hyakudome Tadahiro , Yoshida Hiroshi , Tsukioka Satoshi , Sawa Takao , Ishibashi Shojiro , Aoki Taro , Iwamoto Takashi , Kawaharazaki Yoshinori , Muto Atsutoshi , Oda Tomomasa
Published: May 2009

Development of power sources is one of the most important key technologies for battery-driven underwater vehicles. Usually, many underwater vehicles use rechargeable batteries such as lithium-ion batteries or silver-zinc batteries for their power source. However, in the case of a Long range Cruising type Autonomous Underwater Vehicle (LCAUV), it needs great electric power storage and supply in proportion to the cruising distance. So fuel cells are planned as power the source for this underwater vehicle. A Polymer Electrolyte Fuel Cell and Metal Hydride system is most suitable for underwater vehicles because the PEFC & MH system generates electricity at total efficiency and at low temperature. In 2005, the AUV "URASHIMA" achieved a cruise distance of 317km. Now, the next generation LCAUV which will be able to cruise over 3,000km, is under development using advanced technologies. The technology involved in the hydrogen storage system is one of the important technologies.
Direct High Pressure Hydrogen Production: a Laboratory Scale PEM Electrolyser Prototype.
Authors: Marangio Francesco , Santarelli Massimo , Pagani Matteo , Calì Quaglia Michele
Published: May 2009

Hydrogen production by water electrolysis is a consolidated technology field, but in the last few years the interest is growing. The increasing interest for higher efficiency and low volume hydrogen storage, and the supposed growth of renewable energy power systems have recently motivated new efforts in this domain. In this framework, hydrogen production directly at high pressure is raising increasing interest: in a certain range of pressure, this solution shows higher overall efficiency (from electric power to already compressed hydrogen), and even a positive effect on the system cost thanks to the elimination of the compressor or of some compression stages. Main topic of the paper is the development and validation of the polarisation model of an alpha-prototype laboratory scale electrolyser, developed by Giner Electrochemical Systems (US) and tested thanks to the test bench built at the Dipartimento di Energetica of the Politecnico di Torino in the framework of an agreement with Sapio Spa (Monza, Milan, Italy).
Development of Fuel Processor and Catalyst for a 1kW Class Residential PEFC Co-Generation System
Authors: Komiya Jun
Published: May 2009

PEFC has some desirable characteristics for a small scale co-generation,those are potential for high efficiency and low cost, easiness of start-up and shutdown and so on. Taking this into account, Tokyo Gas Co., Ltd. launched two models of 1 kW class PEFC residential cogeneration systems named LIFUELTM into Japanese market in February 2005. TG has been developing the two systems with Ebara Ballard Corporation and Panasonic Corporation. Fuel processing technologies are very important for a natural gas fuelled PEFC co-generation to achieve high performance. TG has been developing a fuel processor and the technologies have been licensed to EBC. In this paper, our fuel processing technologies and durability evaluation of the fuel processor are reported.
Carbon Sequestration Systems Using Direct FuelCell for Combined Carbon Dioxide Separation and Power Generation
Authors: Ghezel-Ayagh Hossein , Patel Dilip , Sanderson Robert
Published: May 2009

FuelCell Energy (FCE) has developed novel system concepts for separation of carbon dioxide from greenhouse gas emission sources, using Direct FuelCell® (DFC®) technology. DFC is based on carbonate fuel cells featuring internal reforming. The unique chemistry of carbonate fuel cells offers an innovative approach for separation of CO2 from fossil-fuel power plant exhaust streams (flue gasses). DFC-based CO2 separation systems are suitable for many types of coal-based power plants, from existing pulverized coal (PC) plants to future integrated gasification combined cycle (IGCC) plants. The carbonate fuel cell system also produces electric power at high efficiency. Cost of electricity (COE) analysis of the DFC system suggests that the simultaneous generation of power and CO2 capture is an attractive scenario for re-powering the existing coal-fueled power plants.
A Tsunami Ball Approach to Storm Surge and Inundation: Application to Hurricane Katrina, 2005
Authors: Ward Steven N.
Published: May 2009

Most analyses of storm surge and inundation solve equations of continuity and momentum on fixed finite-difference/finite-element meshes. I develop a completely new approach that uses a momentum equation to accelerate bits or balls of water over variable depth topography. The thickness of the water column at any point equals the volume density of balls there. In addition to being more intuitive than traditional methods, the tsunami ball approach has several advantages. (a) By tracking water balls of fixed volume, the continuity equation is satisfied automatically and the advection term in the momentum equation becomes unnecessary. (b) The procedure is meshless in the finite-difference/finite-element sense. (c) Tsunami balls care little if they find themselves in the ocean or inundating land. (d) Tsunami ball calculations of storm surge can be done on a laptop computer. I demonstrate and calibrate the method by simulating storm surge and inundation around New Orleans, Louisiana caused by Hurricane Katrina in 2005 and by comparing model predictions with field observations. To illustrate the flexibility of the tsunami ball technique, I run two “What If” hurricane scenarios—Katrina over Savannah, Georgia and Katrina over Cape Cod, Massachusetts.
The Density‐Dependent Correlations among Observables in Nuclear Matter and Hyperon‐Rich Neutron Stars
Authors: Uechi Schun T. , Uechi Hiroshi
Published: May 2009

The conserving σ‐ω‐ρ mean‐field approximation with nonlinear interactions of hadrons has been applied
to examine properties of nuclear matter and hyperonic neutron stars. The nonlinear interactions that will
produce density‐dependent effective masses and coupling constants of hadrons are included in order to
examine density correlations among properties of nuclear matter and neutron stars such as binding energy,
incompressibility, K, symmetry energy, a4, hyperon‐onset density, and maximum masses of neutron stars.
The conditions of conserving approximations in order to maintain thermodynamic consistency to an
approximation are essential for the analysis of density‐dependent correlations.
In vitro and In vivo Anticancer Activity of Novel Synthetic Makaluvamine Analogues
Authors: Wang Wei , Rayburn Elizabeth R. , Velu Sadanandan E. , Nadkarni Dwayaja H. , Murugesan Srinivasan , Zhang Ruiwen
Published: May 2009

Purpose: The present study was designed to determine biological structure-activity relationships for four newly synthesized analogues of natural compounds (makaluvamines). The compounds, 7-(4-fluorobenzylamino)-1,3,4,8-tetrahydropyrrolo[4,3,2-de]quinolin-8(1H)-one (FBA-TPQ); 7-(phenethylamino)-1,3,4,8-tetrahydropyrrolo[4,3,2-de]quinolin-8(1H)-one (PEA-TPQ); 7-(3,4-methylenedioxyphenethylamino)-1,3,4,8-tetrahydropyrrolo[4,3,2-de]quinolin-8(1H)-one (MPA-TPQ); and 7-(3,4-dimethoxyphenethylamino)-1,3,4,8-tetrahydropyrrolo[4,3,2-de]quinolin-8(1H)-one (DPA-TPQ), were synthesized and purified, and their chemical structures were elucidated on the basis of physicochemical constants and nuclear magnetic resonance spectra.

Experimental Design: The structure-activity relationship of the compounds was initially evaluated by comparing their in vitro cytotoxicity against 14 human cell lines. Detailed in vitro and in vivo studies were then done in MCF-7 and MDA-MB-468 breast cancer cell lines.

Results: The in vitro cytotoxicity was compound, dose, and cell line dependent. Whereas all of the compounds exerted some activity, FBA-TPQ was the most potent inducer of apoptosis and the most effective inhibitor of cell growth and proliferation, with half maximal inhibitory concentration values for most cell lines in the range of 0.097 to 2.297 μmol/L. In MCF-7 cells, FBA-TPQ exposure led to an increase in p53/p-p53, Bax, ATM/p-ATM, p-chk1 and p-chk2, and p-H2AX; and cleavage of poly(ADP)ribose polymerase, caspase-3, caspase-8, and caspase-9. It also decreased the levels of MDM2, E2F1, Bcl-2, chk1/2, and proteins associated with cell proliferation [cyclin-dependent kinase (Cdk)2, Cdk4, Cdk6, cyclin D1, etc.]. Moreover, FBA-TPQ inhibited the growth of breast cancer xenograft tumors in nude mice in a dose-dependent manner. Western blot analysis ofthe xenograft tumors indicated that similar changes in protein expression also occur in vivo.

Conclusion: Our preclinical data indicate that FBA-TPQ is a potential therapeutic agent for breast cancer, providing a basis for the development of the compound as a novel anticancer agent.
Evidence for association of lymphoid enhancer-binding factor-1 (LEF1) with the number of functional and inverted teats in pigs
Authors: Tetzlaff S. , Jonas E. , Phatsara C. , Murani E. , Ponsuksili S. , Schellander K. , Wimmers K.
Published: May 2009

The lymphoid enhancer-binding factor-1 (LEF1) belongs to a family of regulatory proteins that share homology with the high mobility group protein-1 (HMG1). The LEF1 gene is a mediator in the canonical Wnt-signalling pathway required for morphogenesis of early mammary gland during embryogenesis. Here we describe the molecular characterisation of the porcine LEF1 gene and its association with number of teats and inverted teats in experimental and commercial populations. The 2357-bp cDNA sequence contains an 1197-bp open reading frame encoding a protein of 398 amino acids. The porcine LEF1 protein shares high identity with LEF1 in other mammalian species. The LEF1 gene contains 12 exons and maps to pig chromosome 8 (SSC8). We identified two single nucleotide polymorphisms (SNPs), a T1351C transition and an A1666C transversion, in the 3′ end of LEF1. Associations of the SNP A1666C with presence of inverted teats (P≤ 0.01), total number of teats (P ≤ 0.01) and total number of inverted teats (P ≤ 0.01) were highly significant; SNP T1351C showed near significance with total number of inverted teats (P ≤ 0.1) in the experimental DUMI population. SNP T1351C was significantly associated with total number of inverted teats (P= 0.04) and close to significance with affected teats (P = 0.06) in commercial populations. Haplotype analysis confirmed the tendency towards association with affected teats (P = 0.06) in the experimental DUMI population. The function, position, and associations shown here promote LEF1 as a candidate gene for number of teats and in particular for presence and number of inverted teats.
Studies on the short range spreading of the male specific lethal (MSL) complex on the X chromosome in Drosophila
Authors: Sun X. , Birchler J.A.
Published: May 2009

A series of autosomal insertions of chromosomal fragments derived from around the X linked white eye color locus have been examined for male specific lethal (MSL) complex binding using both immunostaining and fluorescence in situ hybridization (FISH) techniques. The results show that the transposing elements (TEs) composed of several genes in the white region (3C2-3C5) do not recruit the MSL complex when inserted into an autosome. The same result is found for the Tp(1:3)wzh insertion, a fragment of the X chromosome inserted into the third chromosome. Two other insertions, Dp(1:2)w70h (3A7-3C2-3) and Dp(1:2)51b (3C2-3D6), which extend more distally or proximally beyond the TE insertion, respectively, display a binding pattern of the MSL complex at the autosomal location. These insertions were also examined in females ectopically expressing MSL-2 and show similar binding activity. In addition, the Tp(3:1)O5 transposition strain containing an autosomal segment in the X chromosome was examined for spreading of the MSL complex. Limited spreading of the MSL complex into autosomal regions was indicated by immunostaining and FISH. This spreading was further confirmed by chromatin immunoprecipitation of the MSL complex covering the autosomal sequences.
E-Selectin Genetic Variation as a Susceptibility Factor for Ischemic Stroke
Authors: Haidari Mehran , Hajilooi Mehrdad , Rafiei Ali Reza , Rezaii Ali Akbar , Hoseinipanah Seyed Mohamad
Published: May 2009

The polymorphism of the E-selectin gene has been implicated in the pathogenesis of atherosclerosis. We sought to explore whether the allelic variants relate to ischemic stroke. We conducted a case-control study of 359 cases of ischemic stroke and 353 community controls. Participants were evaluated for known cerebrovascular risk factors, and the E-selectin S128R and L554F genotypes were established using the polymerase chain reaction (PCR) method. The frequency of minor allele (R) and heterozygous (RS) genotype of E-selectin S128R polymorphism was significantly higher in the stroke patients than in the controls. Evaluation of genetic variation for E-selectin L554F polymorphisms revealed that the frequency of minor allele (F) and its heterozygous genotype (LF) is almost 4 times higher in the stroke patients than the controls (16.7 vs. 4.3 and 33.4 vs. 8.5, respectively). Multivariable logistic regression analysis after adjustment for age, sex and conventional vascular risk factors demonstrated that alleles R of S128R and F of L554F polymorphisms are independent risk factors for ischemic stroke. The combination of 2 minor alleles of E-selectin genes appeared to be the strongest susceptibility factor for ischemic stroke (adjusted OR: 5.89, 95% CI: 2.84–12.21, p = 0.0001). Our study demonstrates that the E-selectin S128R and L554F polymorphisms are associated with susceptibility to ischemic stroke.
Selection and Characterization of Packaging Cell Lines for XJ-160 Virus
Authors: Zhu Wu-yang , Liang Guo-dong
Published: May 2009

Objectives: XJ-160 virus is a mosquito-derived Sindbis-like virus isolated in China. Based on its infectious clone (pBR-XJ-160) we have developed an RNA-based vector system. In this work, we constructed packaging cell lines (PCLs) for XJ-160 virus. Methods: Firstly, XJ-160 virus structural protein expression cassette pcE or pICH was constructed by cloning the gene of glycoprotein E3E26KE1 or capsid protein of XJ-160 virus into pcDNA3.1(+) or pIRES, respectively. Then the PCLs (BHK-21E+Capsid cells) for XJ-160 virus were obtained by two selections with G418 and hygromycin. Results: The results indicate that BHK-21E+Capsid cells, stably expressing E3E26KE1 protein and capsid protein of XJ-160 virus, not only highly increased packaging efficiency of the vector from XJ-160 virus, but also provided packaging function for the vector from Semliki Forest virus. Conclusion: These results suggest potential utility of the PCLs of XJ-160 virus for large-scale vector production and facilitating broad alphavirus applications. Also, the construction of PCLs for XJ-160 virus lays a basis for developing alphavirus-derived vector systems.
Treatment Experience of Subsequent Complications after Roux-en-Y Biliojejunostomy
Authors: Li Z. , Cui N. , Chen L.
Published: May 2009

Purpose: Roux-en-Y biliojejunostomy has been frequently used in the management of benign biliary disease. The aim of this study was to summarize one institute’s experiences in prevention and management of subsequent complications of Roux-en-Y biliojejunostomy. Methods: A retrospective analysis was carried out for patients who underwent reoperation after Roux-en-Y biliojejunostomy from February 1990 through June 2004. Operation history, laboratory test data before the last operation, and images were collected. Results: Sixty-one patients, aged 36–60 years and with a 3.5-year average operation interval, were involved in the study. Anastomotic stricture (47, 80.3%), recurrent calculi (36, 60.7%), and biliary tract infection (all) were the most common complications after Roux-en-Y biliojejunostomy. Other complications (such as calculi of the intrahepatic duct or intrahepatic duct stricture, malformed or twisted jejunum loop, too long or too short proximal jejunum, disappearance of the normal form of anastomosis, and adhesion of the intestinal loop) were also detected by laparotomy. Conclusion: Calculus, stricture, and infection arise as a result of each other. Lessening of the anastomotic stricture, fluent drainage of the distal jejunum below the anastomosis, and relieving pressure of gastrointestinal tract are pivotal in decreasing subsequent complications after Roux-en-Y biliojejunostomy.
Somatic Mutations of the CDC4 (FBXW7) Gene in Hereditary Colorectal Tumors
Authors: Miyaki Michiko , Yamaguchi Tatsuro , Iijima Takeru , Takahashi Keiichi , Matsumoto Hiroshi , Mori Takeo
Published: May 2009

Objectives: Cdc4 (Fbxw7) is a potential tumor suppressor that regulates ubiquitination and proteolysis of multiple targets such as cyclin E, c-Myc, c-Jun and Notch. CDC4 mutations were investigated in 194 colorectal carcinomas and adenomas for comparison between sporadic and hereditary cancers. Methods: Mutations of the CDC4 gene were analyzed by PCR-SSCP and sequencing, and loss of heterozygosity (LOH) was analyzed by microsatellite marker analysis. Results: Somatic CDC4 mutations were detected in 9% (3 of 33) of hereditary nonpolyposis colorectal cancer (HNPCC), 9% (3 of 33) of familial adenomatous polyposis (FAP) carcinomas, and 10% (7 of 73) of sporadic carcinomas. CDC4 mutations were also detected in adenomas at frequencies of 6% (2 of 31) and 4% (1 of 24) in FAP and sporadic cases, respectively. Frameshift mutations were observed in HNPCC tumors, while single-base substitutions predominantly occurred in FAP and sporadic tumors. LOH at the chromosome 4q region was rarely detected in tumors with CDC4 mutations. Conclusions: The results indicate that the frequency of CDC4 mutations in colorectal tumors is similar in patients with HNPCC and FAP compared to patients with sporadic carcinomas. Moreover, infrequent LOH suggests that the CDC4 gene does not follow the general 2-hit model.