bluuebunny/crossref_metadata_2025 huggingface dataset:
Prevalence of Pasteurella multocida and other respiratory pathogens in the nasal tract of Scottish calves
Authors: Hotchkiss E. J. , Dagleish M. P. , Willoughby K. , McKendrick I. J. , Finlayson J. , Zadoks R. N. , Newsome E. , Brulisauer F. , Gunn G. J. , Hodgson J. C.
Published: October 2010

The prevalence of Pasteurella multocida, a cause of bovine respiratory disease, was studied in a random sample of beef suckler and dairy farms throughout Scotland, by means of a cross‐sectional survey. A total of 637 calves from 68 farms from six geographical regions of Scotland were sampled between February and June 2008. Deep nasal swabs were taken, and samples that were culture‐positive for P multocida were confirmed by PCR. Prevalence of P multocida was 17 per cent (105 of 616 calves); 47 per cent of farms had at least one positive animal. A higher prevalence was detected in dairy calves than beef calves (P=0.04). It was found that P multocida was associated with Mycoplasma ‐like organisms (P=0.06) and bovine parainfluenza type 3 virus (BPI‐3) (P=0.04), detected by culture and quantitative PCR of nasal swabs, respectively. Detection of P multocida was not associated with bovine respiratory syncytial virus (BRSV), bovine herpesvirus type 1 (BoHV‐1) or bovine viral diarrhoea virus (BVDV). Mycoplasma‐like organisms, BPI‐3, BRSV, BoHV‐1 and BVDV were detected in 58, 17, four, 0 and eight calves, on 25, five, two, 0 and five of the 68 farms, respectively.
Salmonella infection in cattle in Great Britain, 2003 to 2008
Authors: Carrique‐Mas J. J. , Willmington J. A. , Papadopoulou C. , Watson E. N. , Davies R. H.
Published: October 2010

Surveillance data for clinical disease in cattle in Great Britain due to Salmonella infections were analysed for the period 2003 to 2008 in order to describe seasonality and to investigate possible associations between Salmonella diagnoses and other variables such as region, climate, age and production type. A clear seasonal pattern was shown for Salmonella infection, coinciding with the second half of the year. The incidence of Salmonella Dublin and Salmonella Typhimurium was highest in the west of the country, which has the greatest cattle density, but this was not a feature of diagnoses with other serovars. Abortion was a more common clinical sign of S Dublin infections, but was relatively unusual in the case of S Typhimurium. The observed clinical picture and age of affected animals were largely determined by the seasonality of dairy cattle calving in Great Britain.
Eradication programme for bovine viral diarrhoea virus in Orkney 2001 to 2008
Authors: Truyers I. G. R. , Mellor D. J. , Norquay R. , Gunn G. J. , Ellis K. A.
Published: October 2010

The strategies used and the results obtained in Orkney's bovine viral diarrhoea virus (BVDV) eradication programme over eight years (2001 to 2008) are presented and discussed. The venture was undertaken by local veterinary practices and the Orkney Livestock Association (OLA) with the financial support of the Orkney Islands Council. Participation is voluntary; the programme comprises screening of youngstock, a whole‐herd test if required, elimination of persistently infected animals and strict biosecurity measures and/or vaccination. BVDV‐free herds are certified, and certification is updated annually by retesting the youngstock. The programme aims to minimise economic losses, thereby increasing the competitiveness of the Orcadian cattle industry and to improve animal health and welfare by eliminating virus circulation. Information from databases of the Scottish Agricultural College, Biobest Laboratories and OLA show that despite a significant reduction in the overall prevalence of BVDV on Orkney during the initial stages of the eradication programme, there has been little progress made since 2006 and that some difficulties have been encountered, with herd BVDV breakdowns following initial eradication. These results highlight the need for continued motivation of farmers, strict application of biosecurity measures and/or systematic vaccination of all seronegative breeding animals.
FIRST-PRINCIPLES INVESTIGATION OF STRUCTURAL AND ELECTRONIC PROPERTIES OF THE RECONSTRUCTED ZnO$(000\bar 1)$ and $(0001) (\sqrt{3}\times\sqrt{3})-R30^\circ$ SURFACES
Authors: LI J. M. , LI CHONG , WANG FEI , SUN Q. , JIA YU
Published: October 2010

The surface O or Zn vacancy of ZnO is extremely important, so in this paper we have studied the structural and electronic properties of the ZnO [Formula: see text] O -polar surface with O vacancy and [Formula: see text] Zn -polar surface with Zn vacancy comparatively using the first-principles calculations. For the former case, the topmost oxygen atoms relax outward and the angle between Zn – O – Zn bonds in the topmost double-layer decreases to 105.01° with respect to the unrelaxed surface. However, for the latter case, the topmost zinc atoms relax inward and the angle between O – Zn – O bonds in the topmost double-layer increases to 117.61° with respect to the unrelaxed surface. Both the two reconstructed surfaces become semiconducting property in contrast to the metallic property of the unreconstructed surface. The calculated surface vacancy formation energy [Formula: see text] indicates that the surface with O vacancy is slightly more easier to be formed compared to the surface with Zn vacancy. By employing the technique of ab initio atomistic thermodynamics, we calculated the surface Gibbs free energy to determine the lowest-energy structure, indicating that the surface with O vacancy is more stable than the surface with Zn vacancy under the oxygen poor condition.
HYDROGENIC IMPURITY STATES IN WURTZITE ZnO/MgZnO QUANTUM DOT
Authors: ZENG ZAIPING , WEI SHUYI , WEI JINGBO
Published: October 2010

Based on the effective-mass approximation, considering the built-in electric field effect due to the spontaneous and piezoelectric polarizations, the ground-state donor binding energy of a hygrogenic impurity in a cylindrical wurzite (WZ) ZnO / MgZnO strained quantum dot (QD) is investigated variationally. Numerical results show that the ground-state donor binding energy is highly dependent on the Mg composition, the impurity positions and the QD size. The built-in electric field also induces an asymmetric distribution of the ground-state donor binding energy with respect to the center of the QD. In particular, it is found that the ground-state donor binding energy is insensible to the dot height when the impurity is located at the right boundary of the WZ ZnO / MgZnO strained QD if the dot height is large.
PHASE DIAGRAM OF ONE-DIMENSIONAL t–U–J MODEL WITH ANISOTROPIC ANTIFERROMAGNETIC EXCHANGE
Authors: DING HANQIN , WANG YANSHEN
Published: October 2010

By using the bosonization approach and the weak-coupling renormalization group (RG) techniques, we study the phase diagram of one-dimensional half-filled t–U–J model parametrized by exchange anisotropy λ (0 ≤ λ ≤ 2) in the weak-coupling regime. In the case of anisotropic antiferromagnetic exchange (J > 0) and on-site repulsion (U > 0), the ground state is characterized by the spin-density-wave (SDW) and bond-charge-density-wave (BCDW) insulating phases. We identify the SDW correlation corresponding to the transverse SDW± phases with a gapless spin excitation (Δs=0) for λ < 4/3 and to the longitudinal SDWz phase with a spin gap (Δs > 0) for λ > 4/3, respectively. The charge excitation is always gapped (Δc > 0) in the whole regime, and the BCDW and SDWz phases show a long-range order. We also examine effects of the nonlocal Umklapp scattering of parallel-spin electrons, which play a role to weaken the BCDW phase and to enhance the SDW phase slightly. The results demonstrate that the properties of our model are not identical with those of the conventional t–U–J model.
KHOVANOV HOMOLOGY AND RASMUSSEN'S s-INVARIANTS FOR PRETZEL KNOTS
Authors: SUZUKI RYOHEI
Published: October 2010

We calculate the rational Khovanov homology of a class of pretzel knots by using the spectral sequence constructed by Turner. Moreover, we determine Rasmussen's s-invariant of almost all pretzel knots P(p, q, r) by using Turner's spectral sequence, a sharper slice-Bennequin inequality, and a skein inequality.
Growing the ERM Energy and Climate Change Practice Through Knowledge Sharing
Authors: Etti Susanne , Perkinton Karen , Cheuk Bonnie , Curtis John
Published: October 2010

Given the scale of the climate change crisis and the small window available in which to take action, Environmental Resources Management (ERM) has accelerated and supported the growth of the Energy and Climate Change practice by investing in training, service offering development, sales support, and knowledge management. This paper outlines the innovative approach that the Energy and Climate Change (E&CC) community of practice (CoP) has taken over the last two years to accelerate the growth of the practice using a holistic approach in the promotion of knowledge sharing at all levels across the company. The approach has shown that there are key factors that contribute to the success of the E&CC CoP. Central to this success is the close partnership and relationships between the knowledge sharing facilitator and the business leaders. The approach also demonstrates that the leader must take an active leadership role and spend sufficient time with members of the CoP.
A POLICY WINDOW OPENS: STRATEGIC ENVIRONMENTAL ASSESSMENT IN YORK REGION, ONTARIO, CANADA
Authors: KIRCHHOFF DENIS , MCCARTHY DAN , CRANDALL DEBBE D. , MCDOWELL LAURA , WHITELAW GRAHAM
Published: October 2010

Government agenda setting has been a focus of research in the field of policy sciences for over two decades. The concept of a policy window is explored as a driver of governmental agenda setting. The Regional Municipality of York, Ontario, Canada was chosen as a case study for exploring the application of strategic environmental assessment at the municipal level through a policy window lens. Problem, policy and political streams converged to provide the necessary conditions for improved environmental assessment and infrastructure planning in York Region. A focusing event and the resulting crisis motivated stakeholders to identify and act on the problem. An SEA-type approach was initiated as one key response. A variety of activities were initiated by York Region including the development of a Sustainability Strategy, synchronisation of master planning, wider consideration of alternatives at the master plan level and improved public consultation. Conclusions are drawn and several recommendations are presented and discussed.
GENERALIZED DERIVED ALGEBRAS AND GENERALIZED INDUCED ALGEBRAS
Authors: Phuapong Sarawut , Leeratanavalee Sorasak
Published: October 2010

Substituting for the fundamental operations of an algebra term operations we get a new algebra of the same type, called a generalized derived algebra. Such substitutions are called generalized hypersubstitutions. Generalized hypersubstitutions can also be applied to every equation of a fully invariant equational theory. The equational theory generated by the resulting set of the equations induces on every algebra of the type under consideration a fully invariant congruence relation. If we factorize the generalized derived algebra by this fully invariant congruence relation we will obtain an algebra which we call generalized induced algebra. In this paper, we prove some properties which transfer the starting algebras to generalized derived algebras and to generalized induced algebras.
HW-DIVISIBLE MODULES
Authors: Nikmehr Mohammad Javad , Nikandish Reza
Published: October 2010

In this paper, we introduce a class of R- modules called hw-divisible modules and then we investigate some properties of them.
γ*-SEMI-OPEN SETS IN TOPOLOGICAL SPACES
Authors: Hussain Sabir , Ahmad Bashir , Noiri Takashi
Published: October 2010

The concept of generalized open sets in generalized topological spaces was introduced by A. Csaszar [6,7]. In this paper, we introduce the concept of γ*-semi-open sets and investigate the related topological properties of the associated topologies SOγ*(X) and τγ. We also introduce the concepts of [Formula: see text]-sets and Λsγ-sets which generalize g· Λs-sets and g· νs-sets respectively introduced by Minguel Caldas and Julian Dontchev [5].
REES MATRIX COVERS FOR TIGHT ABUNDANT SEMIGROUPS
Authors: Guo Xiaojiang , Shum K. P. , Zhu Yongqian
Published: October 2010

Rees matrix covers for regular semigroups were first studied by McAlister in 1984. Lawson extended McAlister's results to abundant semigroups in 1987. We consider here a semigroup whose set of regular elements forms a subsemigroup, named tight semigroups. In this paper, it is proved that an abundant semigroup is tight and locally E-solid if and only if it is an F-local isomorphic image of an abundant Rees matrix semigroup [Formula: see text] over a tight E-solid abundant semigroup T, where the entries of the sandwich matrix P of [Formula: see text] are regular elements of T. Our results enrich the result of Lawson on Rees matrix covers for a class of abundant semigroups and extend the results of McAlister on Rees matrix covers for regular semigroups.
Confocal Raman Imaging of N719 Complex Adsorbed onto Anatase TiO2 Film in High Wavenumber Region: Examining the Involvement of Ti-OH Surface Groups
Authors: Lee Kee Eun , Gomez Mario , Elouatik Samir , Demopoulos George
Published: October 2010

In this study, Confocal Raman imaging of two naked and dye-coated TiO2 films (one built from a commercial paste "Dyesol" and one built from an in-house aqueous synthesized anatase variety "Aqueous") is investigated in the high wavenumber region. The use of this technique allows us to further elucidate the binding mechanism of N719 dye complex onto TiO2 involving surface hydroxyl groups. TGA analysis was also conducted to quantitatively measure the OH/OH2 content of the two TiO2 films and correlate it with the Confocal Raman images.
Investigation of a New Conditioning Method for Improved Performance of Non-Nernstian Sensors
Authors: Sekhar Praveen Kumar , Brosha Eric , Mukundan R. , Farber Boris , Shuk Pavel , Garzon Fernando H.
Published: October 2010

The article reports on a new conditioning technique referred to as the pulsed discharge technique to improve the performance of non-Nernstian potentiometric sensors. In this method, the sensor is energized through a series of positive and negative pulses between the electrodes with discharge phases in between. The sensor response is extracted from the discharge characteristics, which depend on the type of gas and its concentration. The data is presented as a combination of variables derived form the discharge characteristics. In this study, a 'La0.8Sr0.2CrO3/YSZ/Pt' sensor configuration was used to investigate this technique. The sensor baseline drift, response, and recovery time was found to improve when the device was subjected to PDT. Further, a 27-fold increase in sensor response was observed per 1000 ppm of NO compared to the device tested in the absence of PDT. The PDT technique is thought to change the interfacial defect concentration by voltage pulses in the solid electrolyte. Subsequent measurement of the relaxation rate after perturbation in the presence of the target gas gives rise to unique discharge characteristics. It is emphasized that this study has to be seen as an initial approach that demonstrates the potential of the novel conditioning principle for improving the non-Nernstian sensor performance.
Sensors Based on Electrochemically Deposited Titania Studied by AFM and EIS Techniques
Authors: Sánchez Marciano , Cuevas C. , Rincón Marina E.
Published: October 2010

We report the sensor behavior of TiO2 films obtained by low voltage electrochemical anodization of titanium sheets. Films characterization was pursued by X-ray diffraction, Scanning Electron Microscopy and Atomic Force Microscopy, to obtain information on films composition, pore diameter, and roughness. The as-obtained films were evaluated as room temperature ammonia gas sensors working on the Schottky diode principle. Changes in films capacitance and resistance upon ammonia adsorption were followed by Electrochemical Impedance Spectroscopy, and the data indicates a typical n-type sensor behavior of the as-deposited porous TiO2 films. The high impedance of these films reveals the importance of uniform lengths and/or thicker pore walls to avoid the spreading resistance of poor quality contacts
Cobalt Doped Sm0.95Ce0.05FeO3-δ for Detection of Reducing Gases
Authors: Bukhari Syed M. , Giorgi Javier B.
Published: October 2010

The newly developed Sm0.95Ce0.05Fe1-xCoxO3-δ perovskites were assessed as sensors for reducing gases. The solid state sensors were prepared in the form of pellets. Sensors with larger particle size and reduced grain boundaries are obtained as the concentration of cobalt is increased. The sensor's surface is enriched with Sm and Co, but the Sm concentration decreases with an increase in cobalt content. The introduction of cobalt in the perovskite lattice results in an increase in lattice oxygen and a decrease in surface adsorbed oxygen. The electrical conductivity responses toward H2, CO and CH4 (1-5%v/v) were measured in air and at different temperatures. The cobalt doping has improved the response to such an extent that H2, CO and CH4 can be detected at room temperature. Response and recovery time of these sensors are associated with surface chemical composition and surface morphology
Development of Thermal Conductivity Type Hydrogen Sensor
Authors: Watanabe Masaya , Inoue Ryuji , Ichikawa Daisuke , Furusaki Keizo
Published: October 2010

In fuel cell system, it is more desirable to monitor hydrogen concentration in fuel gas line for effective power generation and avoiding fuel starvation. For this need, we have developed MEMS hydrogen sensor which employs thermal conductivity measurement as its sensing principle. This sensor has a micro heater on MEMS diaphragm which enables to detect small heat release rate by hydrogen gas flow. This application requires enough robustness in highly humidified fuel gas stream with possible exposure to rich organic silicon contaminants from sealants. We have optimized the sensor design to overcome these technical hurdles by preventing dew condensation inside sensor housing and with simplified sensing algorithm.
Resonance Elastic Light Scattering and Plasmonic Phenomena in Glutathione-Mediated Gold Nanoparticle Assembly
Authors: Reed Zachary , Prance Amanda , Stobiecka Magdalena , Hepel Maria
Published: October 2010

The resonance elastic light scattering (RELS) spectroscopy has been applied to study the interactions of glutathione (GSH) with citrate-capped gold nanoparticles (AuNP). A strong dependence of GSH-induced gold nanoparticle assembly on nanoparticle size has been found. The RELS intensity measurements were carried out in a short reaction time (τ = 60 s) after injection of GSH. The strong interparticle interactions between AuNP are due to zwitterionic forces and intermolecular hydrogen bonding. The AuNP assembly has been confirmed using the surface plasmon UV-Vis spectroscopy. A fast initial adsorption rate of GSH on a clean Au surface, v = 2.4 ng cm-2 s-1, has been measured using a nanogravimetric flow-cell with piezoelectric QC/Au resonator. The adsorption/desorption processes have been evaluated. The RELS spectroscopy has been found as a very sensitive tool for studying interparticle interactions and its applications can be extended to monitor reactivities and assembly of other monolayer-protected metal clusters.
A Model for Mechanical Force Sensing in Conducting Polymers
Authors: Mirfakhrai Tissaphern , Shoa Tina , Fekri Niloofar , Madden John
Published: October 2010

Conducting polymers have been shown to work as force sensors in an electrolyte by generating a voltage or current when the force applied to them is changed. One possible sensing mechanism is the change in the polymer capacitance as a result of an induced tension. This change in capacitance can be related to perturbation of Donnan equilibrium potential by external load. In this paper we present a model using this proposition to predict conducting polymer sensing behaviour. The model also takes the dependence of the sensing voltage on the polymer oxidation state into account. The predicted model results are compared with experimental measurements on a free-standing film of polypyrrole in an aqueous electrolyte of NaPF6. Sensing voltages ranging from ~ 80-110 μV were detected in response to 1.72 MPa change in the polymer stress, when the polymer was at oxidation states of -0.2 V to 0.4 V vs. Ag/AgCl reference electrode. The load-dependent capacitance necessary to induce the observed sensing currents and voltages is determined. The cycle life of the polypyrrole mechanical sensor was also studied and it was shown that after an initial transient period, the sensing current amplitude stays constant for at least 5400 cycles.
Towards Printable Open-Air Microfluidic Devices
Authors: Collord Andrew D. , Branson Eric , Fenton Kyle , Cook Adam W. , Clem Paul , Apblett Chris
Published: October 2010

We have demonstrated a novel microfluidic technique for aqueous media, which uses super-hydrophobic materials to create microfluidic channels that are open to the atmosphere. We have demonstrated the ability to perform traditional electrokinetic operations such as ionic separations and electrophoresis using these devices. The rate of evaporation was studied and found to increase with decreasing channel size, which places a limitation on the minimum size of channel that could be used for such a device.
Development, Optimization and Evaluation of a CF4 Pretreatment Process to Remove Unwanted Interfacial Layers in Stacks of CVD and PECVD Polycrystalline Silicon-Germanium for MEMS Applications
Authors: Bryce George , Severi Simone , Van Hoof Rita , Guo Bin , Kunnen Eddy , Witvrouw Ann , Decoutere Stefaan
Published: October 2010

Poly-crystalline Silicon-Germanium is a promising structural material for post-processing Micro Electro-Mechanical Systems (MEMS) above CMOS due to its excellent mechanical and electrical properties when deposited at CMOS compatible temperatures. In this work we demonstrate a technique of removing unwanted interfacial (silicon-) germanium oxide layers that form on the surface of SiGe depositions as soon as the wafers are removed from the deposition chamber and exposed to an O2 ambient.
Comparison between Nafion and Polybenzimidazole (PBI) Membranes for Fuel Cell Type CO Sensor
Authors: Mochizuki Kei , Kikuchi Takayuki , Sudoh Masao , Ishiguro Yoshiaki , Suzuki Takayuki
Published: October 2010

This study describes a new CO sensor based on a proton exchange membrane for combustion applications over 100 degree C. One of the promising high-temperature polymers is based on the phosphoric acid doped polybenzimidazole (PBI) polymer. Output at less than 300 ppm CO was clearly detected with PBI at around 200 degree C. Based on the polarization curves, the current density approximately linearly decreased with the decreasing voltage. It was found that PBI had a high CO to H2 selectivity in the combustor exhaust. Sensor performance using PBI was less influenced by humidity than Nafion.
Iron Salt-Catalyzed One Pot Nazarov/Michael Reaction in an Ionic Liquid Solvent System
Authors: Ibara Chie , Fujiwara Masamune , Hayase Shuichi , Kawatsura Motoi , Nanjo Masato , Itoh Toshiyuki
Published: October 2010

Cascade type Nazarov/ Michael reaction of pyrrole derivatives has been demonstrated using 5 mol% Fe(ClO4)3•Al2O¬3 as catalyst in an ionic liquid as solvent; we succeeded in obtaining the product in good yield for five repetitions of the reactions without any addition of the catalyst to the reaction system.
Electrochemical Oxidation and Cation Radicals of All-Five and All-Six 1-Substituted Metallatranes (M = Si, Ge): Spectroelectrochemical Study
Authors: Jouikov Viatcheslav
Published: October 2010

Electrooxidation of all-five and all-six membered metallatranes (M = Si, Ge) derivatives of triethanolamine, and those with aryl-fused lateral chains (derivatives of 2,2',2"-nitrilotriphenol and 2,2',2'-nitrilotris(methylene) triphenol) was studied by cyclic voltammetry and EPR-spectroelectro¬chemistry supported by DFT B3LYP/ LANL2DZ calculations. Phenyl and vinyl metallatranes form distonic cation radicals which are more stable than those of triorganyl amino precursors, and can be observed in acetonitrile already at 250 K. EPR-spectroelectrochemistry revealed that spin density in these species is mainly localized on the axially directed and pointed inside the atrane cage pz orbital of nitrogen. Both EPR and Fermi contact coupling from DFT B3LYP/LANL2DZ calculations have shown zero contribution from the metal in the spin delocalization in these species. DFT calculations suggest that the N atom in these cation radicals is practically planar; Ge atom configuration flattens approaches trigonal bipyramid or, like Si, adopts closer to tetrahedral configuration, the trends depending on the substituent.
Voltammetric Investigations of Ketone Complexation by Lewis Acids
Authors: Cheek Graham T.
Published: October 2010

The electrochemical behavior of 9-fluorenone in the ionic liquid 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate (BMPY TfO) has been investigated. Two reversible redox processes characterize the fluorenone redox system in this medium. Addition of hafnium(IV) triflate to fluorenone in BMPY TfO resulted in the appearance of a shifted reduction peak corresponding to reduction of the complexed fluorenone. When hafnium(IV) chloride was added to fluorenone in BMPY TfO, however, no complexation of the fluorenone was observed; however, the fluorenone radical anion was found to undergo interaction with the HfCl4.
The Electrolytic Dissociation of 1,1-Cyclopropanedicarboxylic and 1,1-Cyclobutanedicarboxylic Acids
Authors: Kvaratskhelia Elene , Kvaratskhelia Ramaz
Published: October 2010

With the aid of the suggested by authors original method the dissociation parameters for the dilute (0.0001-0.01M) solutions of 1,1-cyclopropanedicarboxylic and 1,1-cyclobutanedicarboxylic acids were determined. Besides the equations for the accurate calculation of these parameters the simple empirical equations for the fast approximate calculation of the latters are also suggested.
Mobile Micro- and Nano-Instruments: Small, Cheap and under Wireless Control
Authors: Weagant Scott , Smith Andrea T. , Karanassios Vassili
Published: October 2010

This paper deals with miniaturization of a micro-scale and nano-volume, battery-operated, atmospheric-pressure microplasma on a hybrid, quartz-polymer (e.g., Teflon®) chip. Fundamental aspects, for example, for microplasma ignition, for plasma scaling and for measurement of excitation temperatures are discussed in some detail.
Photodetectors and Receivers for 100 GbE Applications
Authors: Bach Heinz-Gunter
Published: October 2010

100 G Ethernet is a forthcoming application to manage the ever increasing data traffic in optical communications, while improving efficiency compared to the common Open Systems Interconnection seven layer model. Short and long-haul transmission distances are differently affected by fiber impairments, thus simple on-off keying used for short distances is complemented by advanced modulation formats, applied to larger distances. Monolithically integrated InP-based photoreceivers, either comprising pin-diodes with travelling-wave amplifiers for electrical post amplification or 90{degree sign} hybrids integrated with a pair of balanced detectors forming coherent Quadrature Phase Shift Keying photoreceivers, are both shown for 100 G Ethernet transmission concepts.
Photoluminescence of CdSe/ZnS Quantum Dots in GaN/Quantum Dots/GaN Wafer Bonded System
Authors: Li Ying , Giles Alexander , Stokes Edward B.
Published: October 2010

Wafer bonding technology is applied to the GaN/quantum dots/GaN system, where CdSe/ZnS Quantum Dots serve as both the active layer and the binding layer. Photoluminescence is observed from quantum dots following wafer bonding at various temperatures under ultra high vacuum condition. Temperature dependences of bond strength and photoluminescence properties are characterized. Annealing at elevated temperature to form wafer bonds degrades photoluminescence intensity and slightly blue shifts the wavelength. Transmission Electron Microscopy is applied to study the physical properties of vacuum annealed QDs, in which agglomeration is observed.
Electric Fields and Chemical Vapor Deposition
Authors: Warwick Michael , Smith Richard , Furlan Neza , Crane Jared , Binions Russell
Published: October 2010

Chemical vapor deposition methodologies are widely employed in a variety of fields such as microelectronics and glazing. Control of film growth and microstructure, and hence film properties, may be limited by precursor properties such as volatility or decomposition chemistry. In this paper we report how the incorporation of an applied electric field to AACVD reactions of vanadyl acetylacetonate in alcohols can influence the microstructure and growth of thin films of vanadium dioxide in unusual and sometimes unexpected ways. The films were characterized using scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Raman Spectroscopy.
Analysis of the Homogeneous Thermal Decomposition of the Tungsten Dimethylhydrazido Complex Cl4(CH3CN)W(NNMe2) Using In Situ Raman Spectroscopy and DFT Calculations
Authors: Lee Jooyoung , Kim Dojun , Kim Oh Hyun , Anderson Tim , Koller Jürgen , Denomme Dan , Habibi Sophia Z. , McElwee-White Lisa
Published: October 2010

The gas-phase decomposition pathways of the tungsten dimethylhydrazido complexes Cl4(RCN)W(NNMe2) (1a: R = CH3; 1b: R = Ph), precursors for single source deposition of WNxCy, were investigated using a combination of experiments and calculations. Raman scattering experiments were performed in an impinging-jet, up-flow, aerosol-assisted CVD reactor to identify reaction intermediates. Density Functional Theory calculations (B3LYP/LanL2DZ) were used to estimate Raman active frequencies and explore the reaction surface. Dimethylamine and methylmethyleneimine, products from N-N cleavage of the hydrazido ligand, were observed under deposition conditions and identified by comparison with previously reported Raman shifts and calculated frequencies.
Novel Surface-Wave-Excited Plasma-Enhanced CVD System with Reciprocating Substrate Motion
Authors: Azuma Kazufumi , Ueno Satoko , Suzuki Masayasu , Konishi Yoshiyuki , Ishida Shinichiro
Published: October 2010

We have developed a novel surface-wave-excited plasma-enhanced chemical vapor deposition (SWP-CVD) system that exhibits reciprocating substrate motion during plasma deposition. The electron density was not affected by the substrate motion during plasma deposition. The system realizes high film homogeneity, which makes it suitable for large-area devices. The homogeneity of the film was improved with increasing substrate velocity, attaining a variation of film thickness of less than 2% at a velocity of 100 mm/s. We have also demonstrated the possibility of easy fabrication of multilayers using this system.
Hot-Wire Chemical Vapor Deposition of Ge2Sb2Te5 Thin Films
Authors: Reso Denis , Silinskas Mindaugas , Kalkofen Bodo , Lisker Marco , Burte Edmund P.
Published: October 2010

Germanium-antimony-telluride or, particularly, Ge2Sb2Te5 (GST) thin films were deposited by hot-wire (HW) chemical vapor deposition (CVD). Tetraallylgermanium (TAGe), triisopropylantimony (TIPSb), and diisopropyltelluride (DIPTe) were used as precursors for germanium, antimony, and tellurium, respectively. The influence of deposition parameters such as a temperature, pressure, and hydrogen content was investigated. It was found that higher temperature, higher pressure, and lower hydrogen flow yielded higher growth rates of the films. An admixture of hydrogen reduced the Te concentration in the GST thin films and enhanced the content of Ge and Sb. The chemical composition could also be shifted by other deposition parameters but these dependences were not as well determined as in the hydrogen case. Generally, higher germanium concentration was related to smaller amount of tellurium. The films deposited at higher pressure showed significantly higher roughness. Additionally, the switching from low resistivity to high resistivity state was tested.
Gallium Assisted PECVD Synthesis of Silicon Nanowires
Authors: Gewalt Annika , Kalkofen Bodo , Lisker Marco , Burte Edmund P.
Published: October 2010

Within the here presented experiments, we researched the gallium assisted growth of silicon nanowires. For previous deposition of the small gallium droplet-like islands, two different modifications of MW-PECVD were tested. First experiments were performed by standard liquid delivery of the Ga containing chemical. In current experiments, the chemical is transported by vapor draw out of a heat able precursor container and pulsed into a carrier gas flow. In both cases a pure organometallic precursor, trimethylgallium was used as gallium source. The results of both delivery methods were compared. As substrates differently treated <111> and <100> oriented p-doped silicon wafers were used. For the subsequently silicon super saturation similarly MW-PECVD was used as growth method. Silane acted as silicon source. Argon and hydrogen worked as plasma enhanced gases. Differences in the growth of the wires due to the change in Ga deposition and the different treatment of the substrates were analyzed.
(Vittorio de Nora Award Address) Towards Energy Storage for Renewable Generation
Authors: Pletcher Derek
Published: October 2010

An energy economy based largely on renewable sources (solar, wind, wave etc) requires energy storage to act as a buffer between generation and the customer. This Vittorio de Nora Award Lecture provides an opportunity to review the possible role of electrochemical technology, particularly redox flow batteries, to meet this demanding application. The soluble lead acid flow battery being developed in Southampton is discussed, highlighting its advantages and the technical barriers to commercial operation.
Alternating Flow Patterns for Copper Plating Uniformity
Authors: Garich Holly , Gebhart Lawrence , Snyder Stephen , Taylor E. J. , Van Zee John , Shimpalee Sirivatch
Published: October 2010

The need for smaller and faster electronic circuits is driving the design of printed circuit board (PCB) interconnects in the direction of finer pitch transmission lines, smaller diameter through holes and vias, and thicker boards with higher layer counts to provide increased circuit densities. Many of the major defects associated with the manufacture of semiconductors and PCBs may be attributed to poor mechanical quality of z-interconnects. Faraday Technology is coupling patented cell geometry with alternating flow schemes to address copper metallization for shrinking interconnect dimensions. Preliminary modeling work provided the initial switching frequency and flow rate targets for the experimental optimization work that is currently underway. This work is anticipated to improve copper metallization uniformity in high aspect ratio z-interconnects, resulting in improved throwing power and mechanical properties as compared to currently available plating cell geometries and agitation mechanisms.
Modeling Water Transport and Swelling in Polymer Electrolyte Membranes
Authors: Silverman Timothy J. , Meyers Jeremy P. , Beaman Joseph J.
Published: October 2010

Swelling of polymer electrolyte membranes with water uptake can cause curling and wrinkling. This leads to the formation of defects in the deposition and drying of catalyst layers from liquid catalyst ink on fuel cell membranes. A transient, nonuniform model of water transport and the relationship between swelling and stress is needed to help understand, predict and control these defects. We present a one-dimensional version of such a model with experimental data that partially validate it. The model shows how the application of stress changes the concentration profile in a membrane, causing a swelling gradient. The model is the foundation for the prediction of swelling-induced distortions of membrane materials in a manufacturing environment.
Mathematical Model of Carbon Corrosion in a Direct Carbon Fuel Cell
Authors: Chen Chia-Chin , Selman J. Robert
Published: October 2010

The Direct Carbon Fuel Cell (DCFC) is a type of fuel cell using carbon as fuel and molten carbonate as electrolyte. Although the primary anodic reaction is believed to be a 4-electron carbon oxidation reaction, to explain the performance of the DCFC in practice it is necessary to consider the 2-electron CO oxidation reaction as well as the reverse Boudouard reaction. Taking these multiple reactions into account, this work develops a 1-D macrohomogeneous model, and investigates the current and concentration distribution in the DCFC anode. The result shows that the active zone is mostly located on the portion of the anode bed nearest the electrolyte matrix, and that the active zone of a 4-cm high anode bed occupies only 30% of the total height. On the upper portion, the overall reaction rate is nearly zero since the overall anodic reaction, composed of two compensating electrochemical reactions, is exactly equal to Boudouard reaction. Therefore, the overall carbon corrosion within the region is contributed not only by chemically driven Boudouard reaction but also by electrochemically driven Boudouard reaction.
Direct Solid-State Electrochemical Synthesis of Silicon Tetrachloride from Silica at Ambient Temperatures and Pressures
Authors: Ari-Wahjoedi Bambang , Fuad Khairul , Ariefin M.
Published: October 2010

Silicon tetrachloride (SiCl4) is one of the most important chemical compounds in the microelectronic industries. Commercial scale synthesis of SiCl4 is usually performed by roasting silica (SiO2) and cokes (C) under flowing chlorine (Cl2) gas at temperatures {greater than or equal to}900oC. At room temperatures and atmospheric pressures, the formation of SiCl4 from Cl2, SiO2 and C can be calculated to be favorable with ΔGreaction as low as -120.77 kJ/mol. This paper reports the use of I-V characterization technique in ambient conditions SiCl4 synthesis via direct solid state electrochemical synthesis reaction, starting with sodium chloride (NaCl), rice-husk derived-SiO2, and C (graphite/charcoal mixture).
Effect of Dissolved Species on the Fluoride Electro-Removal from Groundwater
Authors: Montero-Ocampo Cecilia , Martínez Villafañe J.F.
Published: October 2010

A systematic study of the influence of the concentration of specific ions present in the groundwater (GW) (such as Ca2+, Mg2+, Fe3+ and SO42-) on the fluoride (F-) electro-removal from model water (MW) containing 5.12 mg L-1 of F- by electrocoagulation (EC) process was carried out. The results showed that Ca2+, Fe3+, Cl- and SO42- reduce the F- removal efficiency, while Mg2+ improves such process. The effect of current density applied between 1.5 and 3 mA cm-2 on the F- removal efficiency from GW by EC process was investigated. The results showed that at 3 mA cm-2 the EC treatment time to reduce the residual F- concentration to 1.5 mg L-1 (maximum contaminant level, MCL) was relatively shorter with MW, 1.5 min than with GW, 4 min. The precipitates produced from the EC operation with GW were analyzed by X-ray diffraction (XRD) and its morphology by scanning electron microscopy (SEM).
Properties of Pulse Plated CdSxTe1-x Films
Authors: Murali Ramakrishna K. , Thirumoorthy P.
Published: October 2010

Thin films of CdSxTe1-x were deposited by the pulse electrodepsoition technique using cadmium sulphate, sodium thiosulphate and tellurium di oxide on titanium and conducting glass substrates. Structural studies indicated the formation of polycrystalline films possessing hexagonal structure. The resistivity varies from 53 ohm cm to 8 ohm cm as the stochiometric co-efficient 'x' value decreases from 1 to 0. It is observed that a post heat treatment temperature of 550 C results in high photosensitivity as well as low light resistance. The optical constants, refractive index(n) and extinction coefficient(k) were evaluated from the transmission spectra of the films of different composition.
The Kinetics for Electrochemical Removal of Ammonia in Coking Wastewater
Authors: Liang Zhenhai , Sun Hongyan , Guo Wenqian , Fan Caimei , Hao Xiaogang , Liu Shi-Bin
Published: October 2010

Electrochemical removal of ammonia is a new and effective method in coking wastewater. The reaction mechanism of ammonia removal was proved by stable polarization curve in this paper. First, the supposing of reaction steps of the electrode were proposed. And then reaction parameter of the electrode was measured by Tafel curve. Finally, the reaction mechanism was determined by quasi-equilibrium approach. The results showed that Cl2 + H2O → HOCl + H+ + Cl- was the rate-determining step, the calculated apparent transfer coefficient was uniform to the experimental value.
Characteristics of Pulse Plated ZnS Films Using Nonaqueous Solvents
Authors: Murali Ramakrishna K. , Kala S. , Elango P.
Published: October 2010

Thin films of ZnS were deposited by the pulse electrodeposition technique employing zinc sulphate and sodium thiosulphate in diethylene glycol solution at 80åC and at different duty cycles in the range 6-50%. The films were polycrystalline exhibiting cubic structure. The intensity of the peaks increased with duty cycle. Transmission measurements indicated interference fringes from which the refractive index fo the films were calculated to be in the range of 2.30-2.70. The band gap of the films was in the range of 3.66-3.62 eV with increase of duty cycle. The films exhibited resistivities in the range of 400-50 ohm cm with increase of duty cycle. The films exhibited higher Photoelectrochemical cell output compared to earlier reports.
Organic Positive-Electrode Materials Based on Dialkoxybenzoquinone Derivatives for Use in Rechargeable Lithium Batteries
Authors: Yao Masaru , Senoh Hiroshi , Araki Miho , Sakai Tetsuo , Yasuda Kazuaki
Published: October 2010

The performance of 2,5-dialkoxy-1,4-benzoquinone derivatives as positive-electrode active materials for use in rechargeable lithium batteries was investigated. These derivatives showed stepwise two-electron redox behaviors in cyclic voltammetry, and also exhibited high initial discharge capacities of more than 200 mAh g-1 in charge/discharge tests. In particular, a positive-electrode that used a methoxy derivative showed the largest discharge capacity (close to 300 mAh g-1) among the dialkoxy derivatives tested. These discharge curves imply benzoquinone-based two-electron redox behavior. Theoretical quantum calculations based on the density functional theory (DFT) were also performed to discuss the electrochemical properties of these materials, and supported the experimental results.
Structured Multilayer Electrodes without Nafion for Polymer Electrolyte Membrane Fuel Cells
Authors: Zils Susanne , Wolz André , Michel Marc , Roth Christina
Published: October 2010

The use of alternative support materials and special MEA preparation techniques allow a replacing of Nafion® within the electrode layer. A possible candidate for the replacement is the electron/proton conductive polymer polyaniline (PANI). This material has proven its suitability and stability as support in a fuel cell environment. The incorporation of Pt/single-walled carbon nanotubes (SWCNT) between the PANI layers can improve the electron conductivity of the system. The assembly is fabricated by the newly introduced spray coating technique, in which alternating layers of Pt/PANI or Ru/PANI, and Pt/SWCNT are sprayed directly onto a Nafion® membrane. 3D electrodes are obtained with an expected high porosity and enhanced noble metal utilization. The assembled multilayered electrodes were used at the anode side with a commercial Pt/CB-Nafion® catalyst layer at the cathode side in a real fuel cell test. The MEAs showed high Pt utilization values with an adequate power density.
Electrochemical Characterization of Novel Hybrid Polymer Electrolytes with Multifunctional Additive
Authors: Piszcz Michal , Marczewski Maciej , Wójcik Julita , Siekierski Maciej S.
Published: October 2010

In this article the properties of the electrolyte basing on the product of the reaction of methylalumoxane with oligoethyleneglycols are studied. The electrochemical studies are performed to describe the conductivity and lithium transference number of the system. In addition DSC, SEM, NMR and vibrational spectroscopy studies are used to get more detailed description of the material. Three classes of electrolytes are here taken into consideration. First bases on PEGDME liquid oligoether system modified with the MAO-PEGME branched hetocomposite system. The second one is the branched product itself used as an electrolyte matrix. In the last cas a crosslinked system was obtained by the utilization of PEGDME - PEG mixture. Obtained conductivities were in range of 10-4 S/cm for liquid like systems and above 10-5 S/cm for the solid ones. For LiCF3SO3 containing samples lithium transference number was promising in range from 0.35 to 0.5
Electrochemical Behavior of Carbide Derived Carbons in LiPF6 and LiCF3SO3 Nonaqueous Electrolytes
Authors: Laheäär Ann , Jänes Alar , Lust Enn
Published: October 2010

This paper presents the electrochemical characteristics of electric double layer capacitors (EDLCs) based on two different non-aqueous electrolytes - 1 M LiPF6 and 1 M LiCF3SO3 in ethylene carbonate/dimethyl carbonate (1:1) mixture. The behavior of vanadium carbide derived carbon VC-CDC(800) and titanium carbide derived carbon TiC-CDC(950) in these electrolytes was studied using cyclic voltammetry and impedance spectroscopy. A wide region of ideal polarizability U {less than or equal to} 3.2 V, short characteristic time constant, limiting capacitance up to 129 F g-1, and high energy and power densities were obtained for systems with LiPF6 electrolyte, indicating that this electrolyte can be used in supercapacitors with high specific performance. In case of LiCF3SO3 electrolyte a lower voltage region of ideal polarizability was obtained and the highest discharge capacitance values were about 75 F g-1, explained by the electroreduction of CF3SO3
- anions and partial contamination of electrode surfaces under study.
Proton Conducting Polymer Electrolytes for Electrochemical Capacitors
Authors: Gao Han , Tian Qifeng , Lian Keryn K.
Published: October 2010

Solid polymer electrolytes containing phosphotungstic acid (PWA) and/or silicotungstic acid (SiWA) blended in polyvinyl alcohol (PVA) were investigated. The polymer electrolyte with a mixed PWA and SiWA had a synergistic effect on its proton conductivity over that of pure PVA-PWA or PVA-SiWA electrolytes. When adding a small amount of polyacrylic acid (PAA), a further increase in proton conductivity was obtained. Electrochemical and structural analyses were conducted on these electrolytes as well.
Anion Conduction in Solid Electrolytes Probed by Water Transport Measurement
Authors: Takahashi Hiroki , Takeguchi Tatsuya , Yamanaka Toshiro , Ueda Wataru
Published: October 2010

The application of inorganic materials as electrolyte of alkaline fuel cell is an important task to achieve noble-metal-free and high-temperature-resistant fuel cells. In the present study, water transport during ion conduction through solid electrolyte was measured to seek inorganic materials with anion conduction. We discovered the anion conduction in layered oxide NaCo2O4. Although LiCoO2 has the similar layered structure to NaCo2O4, this oxide showed cation conduction.
Nanoporous Carbon for Electrochemical Capacitors
Authors: Limmer Steven J. , Yelton W. Graham , Siegal Michael , Bunker Bruce C.
Published: October 2010

Nanoporous carbon (NPC) is a purely graphitic material with highly controlled densities ranging from less than 0.1 to 2.0 g/cm3, grown via pulsed-laser deposition. Decreasing the density of NPC increases the interplanar spacing between graphene-sheet fragments. This ability to tune the interplanar spacing makes NPC an ideal model system to study the behavior of carbon electrodes in electrochemical capacitors and batteries. We examine the capacitance of NPC films in alkaline and acidic electrolytes, and measure specific capacitances as high as 242 F/g.