bluuebunny/crossref_metadata_2025 huggingface dataset:
Tissue Distribution and Renal Excretion of Ormetoprim after Intravascular and Oral Administration in the Channel Catfish (Ictalurus punctatus)
Authors: Plakas S. M. , Dickey R. W. , Barron M. G. , Guarino A. M.
Published: November 2008

Ormetoprim is used to potentiate sulfadimethoxine in treating certain bacterial diseases of aquatic species. The tissue disposition and renal excretion of ormetoprim and metabolites were examined after intravascular and oral administration (4 mg∙kg−1) in channel catfish (Ictalurus punctatus). Peak plasma level (0.66 μg∙mL−1) of14C-ormetoprim occurred at 6 h after oral dosing. The oral bioavailability was estimated at 52%. Ormetoprim and metabolites were widely distributed in the tissues. The tissue concentrations were highest in the liver, trunk kidney, head kidney, and spleen. Clearance of the radiolabel from tissues was rapid. The muscle contained 49.3% of the intravascularly administered dose at 2 h; however, at 72 h, less than 1% of the dose remained in this tissue.14C-Ormetoprim was more persistent in the skin than in the muscle. Ormetoprim was extensively metabolized in catfish. After intravascular administration, 21.1% of the dose of14C-ormetoprim was eliminated in the urine in 48 h, predominantly as polar metabolites; less than 4% of the dose was eliminated as the parent compound. Biliary excretion was a minor route of elimination (5–6% of the dose). The data suggest branchial excretion of ormetoprim and/or metabolites.
Effects of an Experimental Lake Acidification on Zooplankton Feeding Rates and Selectivity
Authors: Sierszen Michael E. , Frost Thomas M.
Published: November 2008

Although the changes in plankton community composition that result from lake acidification have been documented, little is known about processes that accompany these changes. Here we report investigations on an important process, zooplankton herbivory, in an experimentally acidified lake. Acidification from pH 6.2 to 5.2 has not directly impaired the ability of several major taxa to gather food. Acidification may indirectly affect selective feeding behavior, through changes in the relative abundance of phytoplankton species. Dramatic shifts in population-level grazing were not reflected in overall community herbivory, because of complementary changes in populations in the reference and treatment lake basins. Hence, integrative system-level functions may be poorer indicators of perturbation than specific, fine-scale processes.
Assessing the Potential Extent of Damage to Inland Lakes in Eastern Canada due to Acidic Deposition. III. Predicted Impacts on Species Richness in Seven Groups of Aquatic Biota
Authors: Minns C. K. , Moore J. E. , Schindler D. W. , Jones M. L.
Published: November 2008

Linked regional chemical and biotic models predicted that at least 20% of all lakes in 15 of 38 secondary watersheds in eastern Canada had lost at least 20% of their potential species richness given 1980 acidic sulphate deposition levels; 20% of lakes in 15 watersheds represents circa 55 000 lakes. Fish and molluscs were the most affected of seven aquatic taxonomic groups, and rotifers the least. Mean percent loss of potential richness in all of eastern Canada ranged from 5.0 to 9.5% for the seven groups of biota under 1980 acidic deposition. Sulphur dioxide emission reductions of 42% in Canada and the United States were predicted to reduce the number of affected watersheds to seven, leaving circa 25 000 lakes with 20% or more loss of potential richness. Greater acidic deposition reductions will be needed to minimize the biotic damage affecting large areas of eastern Canada.
WEIGHTED ADDITIVE MODELS FOR SOLVING FUZZY GOAL PROGRAMMING PROBLEMS
Authors: YAGHOOBI M. A. , JONES D. F. , TAMIZ M.
Published: November 2008

Weighted additive models are well known for dealing with multiple criteria decision making problems. Fuzzy goal programming is a branch of multiple criteria decision making which has been applied to solve real life problems. Several weighted additive models are introduced to handle fuzzy goal programming problems. These models are based on two approaches in fuzzy goal programming namely goal programming and fuzzy programming techniques. However, some of these models are not able to solve all kinds of fuzzy goal programming problems and some of them that appear in current literature suffer from a lack of precision in their formulations. This paper focuses on weighed additive models for fuzzy goal programming. It explains the oversights within some of them and proposes the necessary corrections. A new improved weighted additive model for solving fuzzy goal programming problems is introduced. The relationships between the new model and some of the existing models are discussed and proved. A numerical example is given to demonstrate the validity and strengths of the new model.
SUPERSYMMETRY VERSUS BLACK HOLES AT THE LHC
Authors: ROY ARUNAVA , CAVAGLIÀ MARCO
Published: November 2008

Supersymmetry and extra dimensions are the two most promising candidates for new physics at the TeV scale. Supersymmetric particles or extra-dimensional effects could soon be observed at the Large Hadron Collider. We propose a simple but effective method to discriminate the two models: the analysis of isolated leptons with high transverse momentum. Black hole events are simulated with the CATFISH black hole generator. Supersymmetry simulations use a combination of PYTHIA and ISAJET, the latter providing the mass spectrum. Our results show that the measure of the dilepton invariant mass provides a promising signature to differentiate supersymmetry and black hole events at the Large Hadron Collider. Analysis of event-shape variables and multilepton events complement and strengthen this conclusion.
THE CONFLICT BETWEEN BELL–ŻUKOWSKI INEQUALITY AND BELL–MERMIN INEQUALITY
Authors: NAGATA KOJI , AHN JAEWOOK
Published: November 2008

We consider a two-particle/two-setting Bell experiment to visualize the conflict between Bell–Żukowski inequality and Bell–Mermin inequality. The experiment is reproducible by local realistic theories which are not rotationally invariant. We find that the average value of Bell–Żukowski operator is evaluated by the two-particle/two-setting Bell experiment in question. Bell–Żukowski inequality reveals that the constructed local realistic theories for the experiment are not rotationally invariant. The two-particle Bell experiment in question reveals the conflict between Bell–Żukowski inequality and Bell–Mermin inequality. Our analysis finds the threshold visibility for the two-particle interference to reveal the conflict noted above. The threshold visibility agrees with the value to obtain a violation of Bell–Żukowski inequality.
ELECTRONIC AND STERIC MECHANISMS IN MONO- AND DOUBLE-FLUORINATION OF Cs-C60Cl6
Authors: ZHOU FENG , WEI XIANWEN , SU HAIBIN , FU QIANG , LI QUNXIANG , BOEY FREDDY Y. C.
Published: November 2008

The ab initio studies of [Formula: see text] isomers clearly show the delicate change from sp3 carbon to sp2 carbon inside two five-membered rings of these structures, as analyzed by both geometry and electron delocalization of adjacent bonds next to both rings. Electronic origin of 2-[Formula: see text] with the highest energy among isomers is attributed to the relative increase in orbital energies, localized spatial feature due to lone pairs of chlorines, and π* characteristics for corresponding molecule orbitals. The steric effect not only favors fluorine over phenyl in substituting Cl connected with the 2- C , but also predominates configurations of double-substituted isomers. This work suggests that C s -C 60 Cl 6 can serve as one practical substituting template for synthesizing C s -C 60 F 6.
A PEER-TO-PEER COMMUNICATION INFRASTRUCTURE FOR GROUPWARE APPLICATIONS
Authors: GOTTHELF PABLO , ZUNINO ALEJANDRO , CAMPO MARCELO
Published: November 2008

Many advances have been done to allow groups of people to work together and collaborate in the Internet. Collaborative systems are characterized by the way participants interact. In many cases, equal standing members should cooperate in a non-authoritative environment, where no entity or authority is or should be in charge of regulating the group. Therefore, decentralized communication infrastructures have been hailed as promising alternatives. Recently, decentralized infrastructures based on P2P approaches have drawn the attention of the research community because of their benefits in terms of scalability, robustness, availability and potentials for leveraging computational resources distributed across the Internet. In this paper, a scalable peer-to-peer (P2P) communication Infrastructure for groupware applications is presented. It enables a large number of people to join and cooperate in a robust, decentralized and easy deployable way, without requiring high capacity servers or any other special network infrastructure. The communication infrastructure is based on a binary tree as overlay structure, which implements all groupware communication functionality, including membership management and packet forwarding, at application level, making it an inexpensive and fast deployable solution for equal standing members, such as home users with a domestic connection to the Internet. Two applications, one for synchronous groupware and the other for asynchronous collaboration, have been developed to validate the approach. Comparisons with other communication infrastructures in aspects such as end-to-end propagation delay, group latency, throughput, protocol overhead, failure recovery and link stress, show that our approach is a scalable and robust alternative.
EVOLVING A SOCIAL VISUALIZATION DESIGN AIMED AT INCREASING PARTICIPATION IN A CLASS-BASED ONLINE COMMUNITY
Authors: VASSILEVA JULITA , SUN LINGLING
Published: November 2008

The paper describes the evolution of the design of a motivational social visualization. The visualization shows the contributions of users to an online community to encourage social comparison and more participation. The newest design overcomes shortcomings in the previous two, by using more attractive appearance of the graphic elements in the visualization, better clustering algorithm and by giving up the largely unused in the previous design user customization options. The visualization integrates more information in one view, and uses an improved user clustering approach for representing graphically their different levels of contribution. A case study of the new design with a group of 32 students taking a class on Ethics and Computer Science is presented. The results show that the visualization had a significant effect on participation with respect to two activities (logging into the community and rating resources).
COLORED JONES POLYNOMIALS WITH POLYNOMIAL GROWTH
Authors: HIKAMI KAZUHIRO , MURAKAMI HITOSHI
Published: November 2008

The volume conjecture and its generalizations say that the colored Jones polynomial corresponding to the N-dimensional irreducible representation of sl(2;ℂ) of a (hyperbolic) knot evaluated at exp(c/N) grows exponentially with respect to N if one fixes a complex number c near [Formula: see text]. On the other hand if the absolute value of c is small enough, it converges to the inverse of the Alexander polynomial evaluated at exp c. In this paper we study cases where it grows polynomially.
COBORDISMS OF WORDS
Authors: TURAEV VLADIMIR
Published: November 2008

We introduce an equivalence relation, called cobordism, for words and produce cobordism invariants of words.
The HSP90-SGT1 Chaperone Complex for NLR Immune Sensors
Authors: Shirasu Ken
Published: November 2008

The nucleotide-binding domain and leucine-rich repeat-containing (NLR) proteins function as immune sensors in both plants and animals. NLR proteins recognize, directly or indirectly, pathogen-derived molecules and trigger immune responses. To function as a sensor, NLR proteins must be correctly folded and maintained in a recognition-competent state in the appropriate cellular location. Upon pathogen recognition, conformational changes and/or translocation of the sensors would activate the downstream immunity signaling pathways. Misfolded or used sensors are a threat to the cell and must be immediately inactivated and discarded to avoid inappropriate activation of downstream pathways. Such maintenance of NLR-type sensors requires the SGT1-HSP90 pair, a chaperone complex that is structurally and functionally conserved in eukaryotes. Deciphering how the chaperone machinery works would facilitate an understanding of the mechanisms of pathogen recognition and signal transduction by NLR proteins in both plants and animals.
Self-Government in Our Times
Authors: Przeworski Adam
Published: November 2008

The eighteenth-century ideal of self-government of the people was based on an assumption that renders it incoherent and unrealistic, namely, that interests and values are sufficiently harmonious that each individual needs to obey only himself while living under laws chosen by all. This conception collapses in the presence of heterogeneous preferences. Yet a weaker notion of self-government is logically coherent: A collectivity governs itself if decisions implemented on its behalf reflect the preferences of its members. I define this second-best self-government and analyze whether democratic institutions can satisfy even this definition.
Multiple Nanowire Channel Poly-Si TFTs with Defect Passivation
Authors: Liao Ta-Chuan , Tu Shih-Wei , Lin Wei-Kai , Liu Cheng-Chin , Chang Kuo-Jui , Cheng Huang-Chung , Chien Feng-Tso , Chen Chii-Wen
Published: November 2008

This work studies the NH3 plasma passivation on a novel gate-all-around poly-Si TFTs with multiple nanowire channels (GAA-MNC TFTs). The NH3 plasma passivation can effectively passivate the defects in poly-Si channel and improve the electrical performance of poly-Si TFTs. As comparison to conventional TFTs, the GAA-MNC TFTs with NH3 plasma passivation exhibit outstanding three-dimensional gate controllability and excellent electrical characteristics, which revealed a high ON/OFF current ratio (>108), a low threshold voltage, a steep subthreshold swing, and a near-free drain-induced barrier lowering. Therefore, such the high-performance GAA-MNC TFTs are very suitable for the applications in the system-on-panel (SOP) and three-dimensional (3D) circuits.
Wafer Bonding of Plasma Activated Surfaces
Authors: Plach Thomas , Dragoi Viorel , Mittendorfer Gerald , Wimplinger Markus , Hingerl Kurt
Published: November 2008

Wafer bonding behavior of plasma activated Si and SiO2 surfaces was investigated. Process evaluation was performed by various experiments. Surface energy of wafer pairs bonded after different storage times at room temperature and after thermal annealing at 300{degree sign}C was investigated as a measure of surface activation lifetime. The study of plasma treatment influence on the surface microroughness showed no roughening of surface for various orientation Si substrates. The quality of the bonded interfaces was explored by TEM cross section analysis: these bonded interfaces were found to be very smooth, with no transition from native to thermal silicon dioxide.
Electrochemical Behavior of Thallium Ion in Organic Solvents and its Application to Organic Synthesis
Authors: Tanabe Takamasa , Uno Kanako , Ishikawa Yuichi , Nishiyama Shigeru
Published: November 2008

Anodic oxidation of thallium (I) salts using an anion exchange membrane with organic solvent, produced thallium (III) oxidant with high current efficiency. Evaluation of electro-generated thallium (III) was performed by oxidation of some cyclic olefins carrying aromatic moieties.
Cathodic Adsorptive Stripping Voltammetric Behavior and Determination of Tricyclic Antidepressant Drug Nortriptyline Hydrochloride in Bulk Form and Pharmaceutical Formulation
Authors: Jain Rajeev , Keisham Radhapyari
Published: November 2008

Nortriptyline hydrochloride is second generation commonly administered tricyclic antidepressants used widely in endogenous depression and may also be effective in some cases of reactive depression. The electro reductive behaviour of nortriptyline hydrochloride was investigated and a well-defined cathodic peak was observed. From the electrochemical response the main reduction step was found to be related to the reduction of C=C group. A versatile fully validated voltammetric method for quantitative determination of nortriptyline hydrochloride in commercial tablets has been proposed, where direct dissolution of tablets is carried out in 0.1 M tetraethylammoniumperchlorate (TEAP) containing dimethylformamide (DMF) solutions. Cyclic voltammetric (CV), differential pulse cathodic adsorptive stripping voltammetric (DPCAdSV) and squarewave cathodic adsorptive stripping voltammetric (SWCAdSV) techniques were applied to study nortriptyline hydrochloride at a HMDE, exhibiting a well defined irreversible reduction peak at -1.02 V vs. Ag/AgCl (3M KCl). The current versus concentration plot was linear over the range 0.1 - 4.5 μg mL-1 and 0.1 - 5.5 μg mL-1 using SWCAdSV and DPCAdSV modes respectively, with a minimum detectability of 0.05 μg mL-1 and 0.057 μg mL-1 and with mean percentage recoveries of 99.7 and 99.4 respectively.
Development of Molecular Probes based on Firefly Bioluminescence
Authors: Maki Shojiro A.
Published: November 2008

Firefly bioluminescence enhancement technology is discovered by confirming on rate-determining step of luciferase reaction. This technology can apply to luciferin analogues having various emission colors.
The Influence of Platinum Surface Morphology on the Electrooxidation of Methanol in Alkaline Solutions
Authors: Hayes Joel R. , Zeller Daniel , Friesen Cody
Published: November 2008

In this work we compare methanol oxidation characteristics in pH 0 and pH 14 electrolytes, and examine the effect of methanol concentration and platinum surface condition (e.g. H-UPD, OH adsorption, Pt oxidation/reduction, planar, nanoporous) on the oxidation current. We observe that in rotating disc electrode (RDE) experiments the oxidation currents on smooth platinum decrease with increasing rotation rate. We show that this decrease is associated with increasing the rate at which oxidation intermediates are swept into the bulk electrolyte before being fully oxidized. To increase the dwell time of intermediates a platinum electrode with 3 nm length scale surface porosity was synthesized by dealloying a Pt-Cu alloy. We then perform the same RDE experiments and show that in this case the methanol oxidation current increases with increasing convection. We attribute this behavior to the trapping of reaction intermediates that otherwise were swept away on the polished sample.
Controlled Synthesis of Silver Particles Supported on Carbon Nanocapsules as Electrocatalysts for Oxygen Reduction Reaction in Alkaline Electrolyte
Authors: Chang Yun-Min , Wu Pu-Wei , Lin Ying-Mei , Lin Pang , Chang Yin-Fang , Liang Ru-Meng
Published: November 2008

Synthesis of various sizes particulate Ag supported on carbon nanocapsules (CNCs) were conducted in typical impregnation and wet chemical approach for physical characterization and electrochemical analysis in alkaline electrolyte. XRD of the as-synthesized powders indicated Ag in FCC phase. In i-V polarizations, the nano Ag/CNCs derived wet chemical route exhibited much enhanced oxygen reduction reaction capabilities than those of Ag/CNCs from impregnation method. Similar behaviors were recorded in galvanostatic discharging measurements between 10 and 200 mA/cm2.
A Dusty Fluid Model to Predict Hydroxyl Ion Conductivity in Alkaline Anion Exchange Membranes
Authors: Grew Kyle N. , Chiu Wilson
Published: November 2008

Recent advances in radiation grafting methods have made quaternary ammonium-based alkaline anion exchange membrane (AAEMs) fuel cells an attractive option for portable power applications. The alkaline environment of the AAEM provides several advantages that stem from the transport of hydroxyl ions across the membrane and the fuel flexibility this permits. However, demonstration of AAEM fuel cells has shown considerable losses in the form of activation and ohmic overpotentials. This work describes a dusty fluid model used to predict AAEM conductivities as a function of relative humidity and physical membrane description. A percolation model is used to account for the membrane structure and validated to Nafion 115 conductivity data.
Studies in the Oxidation of Carboxylic Acids: New Twists for an Old Reaction. Synthesis of Various Cyclic Systems and Substituted Orthoesters
Authors: Lebreux Frédéric , Buzzo Ferdinando , Marko Istvan
Published: November 2008

The Kolbe reaction is probably one of the most famous reactions in organic electrochemistry and innumerable contributions have been reported since its discovery in 1834. However, many original applications of this old reaction still await to be exploited. In this Communication, we wish to describe the development of two novel methodologies based upon the Kolbe reaction and directed towards the synthesis of various cyclic systems and substituted orthoesters.
Silyl Radicals by Reverse and One-Electron Electrochemistry
Authors: Jouikov Viatcheslav V.
Published: November 2008

Silicon-centered radicals R3Si•, both as short-lived intermediates and as persistent species, were produced by means of electrochemistry. The one-electron electrochemical oxidation of silyl anions prepared by various methods (sonochemical cleavage of disilanes with K, reductive electrochemical titration of monochlorosilanes and by reverse electrochemistry in a flow-through cell) resulted in R3Si• radicals, which were involved in radical silylation of double bonds or trapped with PTBN as shown by EPR-spectroelectrochemistry. The same radical species were produced by oxidation-reduction of hexaphenyldisilane in a flow-through teo-compartment cell. The possibility of generating silyl radicals by direct one-electron cathodic reduction has been demonstrated.
Towards Molecular-Level Understanding of Electrocatalytic Hydrogenation. A Comparison of Cyclic Voltammetric Behavior of Benzene Adsorption at Pt(111) Single Crystal Electrodes in Aqueous HClO4 and H2SO4
Authors: Obradovic Maja , Jerkiewicz Gregory , Lessard Jean
Published: November 2008

We present new results on the influence of (C6H6)ads on the HUPD and anion adsorption on the Pt(111) electrode in aqueous HClO4. The Pt(111) electrode is modified by an overlayer of C6H6 ads upon its cycling in the 0.05-0.80 V range in aq. acid + 1 mM C6H6. The (C6H6)ads overlayer significantly changes the HUPD (underpotential deposited H) and anion adsorption, and cyclic-voltammetry (CV) profiles show a sharp cathodic peak and an asymmetric anodic one in the 0.05-0.80 V potential range. The C6H6 ads layer blocks the perchlorate and sulphate anion adsorption but facilitates the adsorption of one monolayer of HUPD which is embedded in the Pt(111) surface. The behavior described above in aq. HClO4 is the same as that in aq. H2SO4. Cycling in the 0.4-1.25 V potential range in benzene-free aq. HClO4 results in the complete oxidation of (C6H6)ads to CO2, which allows the determination that a quasi full monolayer of (C6H6)ads lies on the surface.
Polarographic Studies of Reactions of Three Isomeric Benzenedicarboxaldehydes with Ammonia (NH3) and 2-Aminoethanol (H2NCH2CH2OH)
Authors: Zuman Petr , Kulla Eliona
Published: November 2008

The equilibrium constants of the reactions of isophthalaldehyde and terephthalaldehyde with ammonia and 2-aminoethanol were determined using mostly polarographic limiting currents. Addition of ammonia to orthophthalaldehyde results in a formation of a carbinolamamine, which is first dehydrated to yield an imine, later forms a reducible isoindole derivative. Such derivative is also formed in the reaction of this dialdehyde with 2-aminoethanol. Reaction scheme is presented.
Electron Transfer Dynamics Through Supramolecular Associations
Authors: Frontana Carlos E. , Gonzalez Ignacio , Gonzalez Felipe de Jesus
Published: November 2008

An analysis on the effects that selective hydrogen bonding has in electron transfer kinetics is presented. The study of the interactions between 1,3-dimethylurea and electrogenerated radical anions from a series of substituted nitrobenzenes revealed that the binding constants between such species diminishes in the order -H > -OCH3 > -CH3 > NH2. Also, the results revealed that the reorganization energy involved in such electron transfer processes changes depending on the relative position of the substituent (ortho or para), respect to the position of the nitro moiety. Employing spectroelectrochemical-ESR results and electronic structure calculations, this effect was attributed to modifications in the outer reorganization energy component for ortho substituted compounds, and to the inner component in the case of para substitution.
Linear Sweep Voltammetry of N-Bromosuccinimide
Authors: Haque Inam U. , Akram Wajiha , Iqbal Shahid , Sadaf Shamaila
Published: November 2008

Linear sweep voltammetry of N-bromosuccinimide at glassy carbon electrode in aqueous nitrate solution yielded a single, irreversible reduction wave. The cathodic peak current showed linear variation with concentration of N-bromosuccinimide. The reduction wave was simulated and kinetic parameters evaluated. Pulsed (differential and normal) voltammetric techniques are explored for determination of N-bromosuccinimide
Passive Thermal Management System for Plug-in Hybrid and Comparison with Active Cooling: Limitation of Temperature Rise and Uniformity of Temperature Distribution
Authors: Sabbah Rami , Kizilel Riza , Selman J. R. , Al-Hallaj Said
Published: November 2008

A passive thermal management system using a matrix of graphite phase change materials (PCM) suitable for cooling Lithium-Ion batteries in a plug-in hybrid electric vehicle (PHEV) is compared with that of active (forced air) cooling system. Numerical simulations for both systems were performed at different discharge rates, different operating and ambient temperatures. The results were compared with experimental results conducted for validating the model. The results show that at stressful conditions, i.e. at high discharge rates and at high operating or ambient temperatures (for example 40-45{degree sign}C), air-cooling alone is not an adequate thermal management system to keep the temperature of the cell in the desirable operating range without expending significant fan power. On the other hand, the passive cooling system is able to meet the operating range requirements under these same stressful conditions without the need for additional fan power.
State Analysis of Lithium-Ion Batteries Using Discharge Curves
Authors: Honkura Kohei , Honbo Hidetoshi , Koishikawa Yoshimasa , Horiba Tatsuo
Published: November 2008

It is essential to derive and quantitatively evaluate the parameters of capacity fade in order to understand degradation mechanisms of lithium-ion batteries. Capacity is directly connected with the discharge curve, and it can be reproduced from cathode and anode specific discharge curves. The states of lithium-ion cell cathodes and anodes were accurately estimated using nondestructive state analysis. The cell discharge curve was well reproduced for both the initial and deteriorated states from the specific cathode and anode discharge curves, the amounts of accessible active materials in each electrode, and the alignment between cathode and anode discharge curves. This method was used in a calendar-life test to separately evaluate the decrease in the amounts of active materials in each electrode and the increase in irreversible lithium loss.
Coinsertion of Water and Hydrogen in Transition Metal Oxides and Hydroxides Studied by QCM
Authors: Spicák Petr , Svoboda Vit , Sedlarikova Marie , Kazelle J. , Vondrak Jiri
Published: November 2008

The nickel hydroxide Ni(OH)2 is widely used as active electrode material in Ni-Cd and Ni-MH batteries. The aim of this work is compare mass changes of β and α form during cycling by cyclic voltammetry and EQCM (Electrochemical Quartz Crystal Microbalance). We tested both materials at the electrochemical reduction/oxidation in 0,5 M KOH using cyclic voltammetry and EQCM with the aim to observe absorption and desorption or water
In-situ Surface Recombination Measurement of Oxygen and Chlorine Atoms on Dynamic Stainless Steel Surfaces in Inductively Coupled O2 and Cl2 Plasmas
Authors: Stafford Luc , Khare Rohit , Guha Joydeep , Donnelly Vincent M.
Published: November 2008

We investigated the desorption dynamics of O2 and Cl2 molecules from electropolished stainless steel surfaces following Langmuir-Hinshelwood (i.e., delayed) heterogeneous recombination of oxygen and chlorine atoms, using the spinning-substrate technique. Near real-time elemental analysis by in-situ Auger electron spectroscopy showed that the stainless steel surface became rapidly coated with a Si-oxide-based layer (Fe:[Si+Al]:O = 1:2:9 for O2 and Fe:Si:O:Cl = 1:7:15:6 for Cl2), due to the slow erosion of the fused silica discharge tube and anodized Al chamber walls. For O atoms, the recombination probability was 0.09 {plus minus} 0.01 and was independent of the O flux impinging onto the surface. The recombination probability of Cl atoms ranged from 0.004 to 0.03 and increased with Cl-to-Cl2 number density ratio.
Challenges of High Aspect Ratio Oxide Etching
Authors: Koehler Daniel , Fischer Dominik
Published: November 2008

Plasma etch processes for fabrication of contact holes in SiO2 with aspect ratios of 20:1 and beyond were successfully developed. Both etch rates and profile control mechanisms were investigated in depth. Profile bowing, potato-shaped cross-sections, and increase of length to width ratio were identified to be the limiting factors in patterning of high aspect ratio holes in SiO2. Solutions for bow reduction and the handling of length to width ratio were developed and successfully implemented.
Organic Offset Deposition by Innovative Plasma Technology: Channel Length Modulation for NOR Flash Memories
Authors: Zanderigo Federica , Piumi Daniele , Ghilardi Tecla , Camozzi Elisa , Scintu Petronilla , Boccardi Maria Rosaria , Zhu Helen , Sadjadi Reza , Romano Andy
Published: November 2008

NOR flash memories typically use a Self Aligned Source (SAS) approach to increase array density and reduce device size. A low resistance source line common to adjacent cells in different bitlines is obtained by etching field oxide and implanting N-type dopant. The thin organic layer left by reactive ion etch (RIE) acts as a spacer during the implantation step, impacting the effective channel length and the source line resistance. Cell parameter variations induced by unpredictable changes of this film cannot be neglected as second order effects for 65nm and subsequent technology nodes. This paper discusses a new plasma technology application focused on this topic: after removing the organic film left by RIE, a tunable offset spacer has been purposely deposited on cell sidewalls and characterized by means of TEM analyses. The corresponding electrical impact on cell properties is reported and discussed.
Invetigations of Ultrathin Ru-WCN Mixed Phase Films for Diffusion Barrier and Copper Direct-Plate Applications
Authors: Greenslit Daniel V. , Kumar Sumit , Chakraborty Tonmoy , Eisenbraun Eric
Published: November 2008

A novel mixed phase Ru-WCN film grown by plasma enhanced atomic layer deposition (PEALD) has been investigated as a novel direct plate liner for advanced copper metallization. Ru/WCN films have been grown using a nanolaminate approach. Preliminary results show that composition and thickness of the film both contribute to the ability of the film to facilitate dense copper plating. TVS barrier test results indicate that 3 nm thick liners with metal ratios as high as 11:1 Ru:W can be employed as a platable Cu diffusion barrier.
Effect of Biofilm Properties on the Electrochemical Performance of Microbial Fuel Cells
Authors: Ramasamy Ramaraja P. , Ren Zhiyong , Redcloud-Owen Susan , Mench Matthew M. , Regan John
Published: November 2008

With much of the MFC research around the world being focused on the engineering of the reactors, understanding the fundamental relationship between the microbiology and electrochemistry is critical to the advancement of this technology. Biofilms of variable thickness were grown separately in different microbial fuel cell reactors which were subjected to extensive electrochemical and microbiological tests. The correlation between microbial biofilm properties and the electrochemical performance was investigated in detail. It was found that the cell count, biofilm density and the type of communities in the anode biofilm had a direct influence on the power output of microbial fuel cells. Also the power density was directly dependent on the biofilm growth and increased significantly during the initial biofilm growth period. A variation in the biofilm morphology and composition was observed during the biofilm growth period which may have a serious impact on the performance of the microbial fuel cells.
Electrochemical Dynamics of Producing Power from Treating Organic Wastewater in Biofuel Cell
Authors: Wang Li , Wang Changsong , Cao Xu , Li Xiaona , Yu Honghai
Published: November 2008

Bio-fuel cell was comprised of two chambers with inserted anode and cathode containing proton permeable ionic exchange membrane in treatment of organic waste and wastewater. The anodic chamber was seeded with mesophilic clostridium sp., and was able to couple with a buffer solution as cathodic electrolyte through the membrane in cathodic chamber. The electrochemical process was measured by using a monitoring system. The electrochemical dynamic process was investigated by the testing platform of common geometry when the bio-fuel cell operated and generated a steady state current and voltage. The mathematic model was setup by electrochemical dynamics. The reacted process dynamics was calculated by the finite element analysis method. It is useful to improve its performance.
Self Assembled Monolayer (SAM) of Metallomacrocycle as a Synthetic Cathode Catalyst for a Hybrid Bio-fuel-cell
Authors: Gervasio Dominic , Thomson Jeffery
Published: November 2008

A hybrid bio-fuel-cell (HBFC) has one electrode with an enzyme catalyst and another with a synthetic catalyst. A new cobalt(II) porphyrin, Co1, was synthesized as an oxygen reduction catalyst for a cathode in a HBFC. Co1 has a covalently attached phosphonate group, which gives Co1 affinity for metal oxide so it can form a self-assembled monolayer (SAM) on an electrode with an oxide surface. Voltammetry of a SAM of Co1 on an indium tin oxide (ITO) electrode in aqueous 0.01 molar TFMSA solution equilibrated with 1 atmosphere of Argon showed a surface charge corresponding to a monolayer of Co1. In the same triflic acid solution equilibrated with oxygen, a bare ITO electrode did not reduce oxygen at any potential, but the same ITO electrode after coated with a SAM of Co1 exhibited substantial oxygen electro reduction current, which began at 0.65 V versus NHE and was not affected by the presence of methanol. This selectivity indicates that a SAM of Co1 is a promising catalyst for a cathode, which can selectively scavenge oxygen from biological sera which also contains alcohols and other organic species.
Mediated Enzyme Electrodes for Biological Fuel Cell and Biosensor Applications
Authors: Boland Susan , Kavanagh Paul , Leech Donal
Published: November 2008

Integration of enzymes, redox mediators and high surface area materials to provide bioelectrochemical platforms capable of efficiently transferring electrons between chemicals and electrodes is a dynamic and rapidly expanding research area. These bioelectrochemical reactions are enabled by designing efficient mediated electron transfer processes between selected enzymes and electrode materials. Targeted synthesis of a library of osmium based redox mediator complexes possessing a range of redox potentials is presented whereby these mediators are designed to possess the dual function of mediation and covalent immobilization. In addition to designing inbuilt immobilization strategies for mediators, anchoring a support to surfaces can improve the stability of an enzyme/mediator layer compared to physisorbed films. An overview of some of the strategies we have adopted towards the fabrication of these anchored redox active biocatalytic films on supported pre-functionalized electrodes is presented.
Sony's Biofuel Cell
Authors: Tokita Yuichi , Nakagawa Takaaki , Sakai Hideki , Sugiyama Taiki , Matsumoto Ryuhei , Hatazawa Tsuyonobu
Published: November 2008

We have developed the passive-type biofuel cell having 3.0mW/cm2 power at 500 mV and 800 mV open circuit voltage. This performance has been achieved by introducing 2-amino-1,4-naphthoquinone (ANQ) as an anode electron mediator. Although the redox potential of ANQ, -0.36V (vs Ag/AgCl) is much more negative than that of vitamin K3 (VK3), -0.22V, the kcat value of diaphorase (DI) against ANQ, 620 sec-1 is not so small in comparison with that of VK3, 1300 sec-1. This character has been maintained even in the immobilized electrode modified by DI and ANQ, so that the biofuel cell power has increased from 1.5mW/cm2 of VK3 to 3.0mW/cm2 of ANQ.
Simulation of Multi-Step Enzyme Electrodes
Authors: Hettige Chaminda , Minteer Shelley , Calabrese Barton Scott
Published: November 2008

Incorporation of multiple enzymes on electrode surfaces can enhance the fuel efficiency of biofuel cell anodes, by sequentially catalyzing intermediate reactions such that fuel is completely oxidized. A quantitative study of multiple enzyme systems immobilized on porous electrodes is presented, considering immobilization of all enzymes uniformly codispersed in the same phase, as well as dispersion of individual enzymes in separate phases. Multiple phases maintain nonuniform pH conditions to enable optimum activity of each enzyme, while offering exposure to a common to the anode surface where the cofactor acting as a mediator may undergo oxidation. Comparisons have been made with the performance of electrodes with all the enzymes in a single electrode phase, identifying kinetic and transport conditions under which multi-phase immobilization shows improvement over single phase systems. The models are applicable to more electron rich enzyme reaction systems.
Ion Conductivity Enhancement Effect by Introduction of Dislocations in Yttria-Stabilized Zirconia
Authors: Saito Yuji , Cheng Jeremy , Crabb Kevin , Huang Hong , Pornprasertsuk Rojana , Su Pei Chen , Prinz Fritz
Published: November 2008

High dislocation density in zirconia systems may significantly affect oxygen ion conductivity. Several processes for introduction of high dislocation density were investigated including ion irradiation. YSZ single crystals were irradiated with Ar+ ions and dislocations were observed by TEM. After heat treatment, high dislocation density was observed in a certain range of depth, and no dislocations were observed in the vicinity of the surface. Conductivity measurements by AC impedance spectroscopy indicated that conductivity improved by 55%.
CO Electrochemical Oxidation on Ni Patterned Anodes for Assessing Solid Oxide Fuel Cell Kinetics
Authors: Habibzadeh Bahman , Sukeshini A. Mary , Becker Benjamin , Jackson Gregory S.
Published: November 2008

To eliminate complications associated with gas-phase transport in porous SOFC anodes, microfabricated Ni patterned anodes on YSZ electrolytes have been studied with impedance spectroscopy and voltammetry to evaluate CO electrochemical oxidation under dry and wet conditions. The patterned anodes provide a measure for approximating charge transfer rates per length of three-phase boundary. Adding ~ 3% H2O (by mole) to CO/CO2 anode flows increases exchange current densities by approximately 1.5X for temperatures between 700 and 800 {degree sign}C. This suggests that water gas shift does create adsorbed H on the Ni electrocatalyst for increased charge transfer rates. However, comparison with H2 exchange current densities indicates that CO electrochemical oxidation is still the dominant source of Faradaic current. Analysis of the measured impedance spectra for the dry and wet CO/CO2 anode flows reveals that both high-frequency charge transfer activation and low-frequency adsorption and surface diffusion are contributing significantly to the measured anode overpotentials.
Stability of Zr-Doped SrCeO3-d Under Wet CO/CO2 Atmospheres
Authors: Li Jianlin , Yoon Heesung , Oh Tak-Keun , Wachsman E. D.
Published: November 2008

The SrCeO3-based perovskite is a potential hydrogen membrane material used to incorporate the water gas shift reaction catalyst and hydrogen separation into one unit. The stability of SrCeO3 was improved using zirconium dopant. A tubular hydrogen membrane was fabricated with NiO-SrCe0.8Zr0.2O3 and SrCe0.7Zr0.2Eu0.1O3 as the substrate and membrane, respectively. The hydrogen permeation flux was stable under wet CO atmosphere.
BaCe1-x-yZrxYyO3-d Proton Conductors: The Role of the Synthetic Route on their Properties
Authors: Barison Simona , Battagliarin Marino , Boldrini Stefano , Chiodelli Gaetano , Doubova Lioudmila , Fabrizio Monica , Gerbasi Rosalba , Malavasi Lorenzo , Mortalo' Cecilia
Published: November 2008

Proton conducting electrolyte materials are promising candidates for the development of low temperature solid oxide fuel cells. Among them, various doped barium cerate compounds, such as BaCe1-xYxO3-δ, have been intensively investigated because of their high proton conductivity. As a drawback, cerates are chemically unstable in CO2-containing atmospheres, such as in case of hydrocarbon or syngas fuelled fuel cells. Conversely, doped barium zirconates electrolyte materials exhibit high chemical stability but lower proton conductivity. A goal of this work was to obtain full-density proton conducting materials having both high conductivity and good chemical stability. In particular, the compositions investigated in this work were BaCe1-x-yZrxYyO3-δ (x=0, 0.1, 0.2, 0.3, 0.4; y=0.15, 0.20). The partial substitution of Ce by Zr in doped barium cerate considerably increased their chemical stability in CO2 atmosphere without sensibly affecting the conductivity.
Performance of IT-SOFC with Ce0.9Gd0.1O1.95 Functional Layer at the Interface of Ce0.9Gd0.1O1.95 Electrolyte and Ni-Ce0.9Gd0.1O1.95 Anode
Authors: Ahn Jin Soo , Yoon Heesung , Wachsman E. D.
Published: November 2008

In this work we present a method for dispersing nano-sized Ce0.9Gd0.1O1.95 (GDC) particles at the GDC electrolyte and Ni-GDC anode interface. Dispersed nanosized particles were deposited to form an anode functional layer (AFL). Anode supports were prepared by tape casting of large micron-sized NiO powder and sub micron-sized GDC powder without pore former. For the cathode a La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF)-GDC composite was used. Without an AFL the open circuit potential (OCP) and the maximum power density were 0.677 V and 286 mW/cm2, respectively, at 650 {degree sign}C. With an AFL the OCP and the maximum power density increased to 0.796 V and 486mW/cm2, respectively, at the same temperature. Two point probe impedance measurements revealed that the AFL fabricated by the proposed method not only increased the OCP but also reduced the anode polarization. The effect of AFL pre-sintering is also presented.
Fabrication and Characterization of Light-Weighted Micro Tubular SOFCs
Authors: Suzuki Toshio , Funahashi Yoshihiro , Yamaguchi Toshiaki , Fujishiro Yoshinobu , Awano Masanobu
Published: November 2008

Micro tubular SOFCs have shown characteristic features as high thermal stability during rapid heat cycling and high volumetric power output, which is expected to overcome several problems shown in conventional (planar) SOFCs. Here we report light-weighted tubular solid-oxide fuel cells under 1 mm diameter operable under 600oC. The cell consists of ordinary materials but has new anode microstructure with high porosity of 46 % (before reduction) and reduced anode thickness of less than 200 B12-0794RB12-0794R mm. Thus, the weight of the single cell was 0.015 g per 1 cm length, 0.06 g per 1cm2 surface (electrode) area) The results showed that the performance of the cell was 628, 1017 and 1293 mW/cm2 at 500, 550 and 600oC with wet H2 fuel, respectively.
YSZ-Based Electrochemical Gas Sensors for the Detection of Explosives
Authors: Brosha Eric L. , Mukundan R. , Garzon F. H.
Published: November 2008

A zirconia-based mixed potential sensor utilizing dense lanthanum chromite and Pt electrodes and porous YSZ electrolyte was used in an alternating HC mode (unbiased) and total NOx mode (50 nA bias current applied) to detect the HC and NOx deflagration remnants of a nitroglycerin/nitrocellulose propellant (Bullseye{trade mark, serif}), ANFO (ammonium nitrate and fuel oil), blackpowder, and urea (a common, high nitrogen content fertilizer.) Unique HC and NOx sensor responses taken together with sufficient sensitivity to detect microgram quantities of Bullseye{trade mark, serif} - both directly and via capture of trace residue by swiping contaminated surfaces- suggest that detection and discrimination of HE using zirconia-based mixed potentials is possible.
Multifunctional Gas Sensor Array with Improved Selectivity Through Local Thermal Modification
Authors: Blackburn Bryan M. , Wachsman E. D.
Published: November 2008

This work involves the development of small, easily manufactured, potentiometric gas sensor arrays for continuous monitoring of pollutant (NOx, CO, HCs) concentrations. These low-power devices consist of coplanar sensing electrodes operating in the same gas environment without the need for an air-reference. The selectivity of a sensing electrode-pair is temperature dependent and may be enhanced with the use of integrated heating elements. Finite Element Modeling was used to predict thermal distributions and find the ideal locations of sensing electrodes and heating elements. General trends of baseline shift and sensitivity with changes in individual electrode temperatures are discussed. The results demonstrate that a gas sensor array with thermally modified sensing electrodes yields a device capable of selectively determining the concentrations of combustion byproducts.
Isotopically Labeled Oxygen Studies of the Exchange Behavior of Nox Over La2cuo4
Authors: Van Assche F. Martin , Wachsman E. D.
Published: November 2008

The harmful nature of nitrogen oxides (NOx) to environmental systems necessitates sensors to detect their presence. One effective means is the use of solid state sensors. These sensors are compact, rugged, and can be inexpensively fashioned, making them a viable option for measuring gas concentration. A non-Nernstian potentiometric sensor can be used to detect low concentrations of NOx gas in multiple regions of oxygen concentration. Understanding the mechanism for this behavior can assist in optimizing the sensor couple for a given application. Previous studies using Temperature Programmed Reaction and Desorption (TPR/TPD), along with IR and XPS analysis, have identified the formation of charge-building compounds that establish voltage on the sensing electrode when exposed to NOx gas. To further evaluate the mechanism, TPR and TPD were performed using isotopically labeled oxygen with simultaneous exposure to NOx.
Compositional Stresses in Polycrystalline Ceria Films
Authors: Mandowara Sunil , Sheldon Brian
Published: November 2008

Nanocrystalline ceria generally has significantly higher defect concentrations and more oxygen nonstoichiometry than coarse grained material that is equilibrated at the same temperature and oxygen partial pressure. The volume changes associated with such high nonstoichiometry can lead to significant stresses in constrained ceria films. This may have significant implications for applications such as solid electrolytes, where stresses can lead to mechanical failures. To systematically study these compositionally induced stresses, ceria films with varying film thickness were grown by MOCVD and in situ stress measurements were made by monitoring changes in the curvature. The results show that nanocrystalline films exhibit significantly higher compositional stresses than coarse grained films. The film thickness also appears to have a measurable effect on the observed compositional stresses.