bluuebunny/crossref_metadata_2025 huggingface dataset:
The influence of web silk decorations on fleeing behaviour of Florida orb weaver spiders, Argiope florida (Aranaeidae)
Authors: Bateman Philip W. , Fleming Patricia A.
Published: May 2013

Spider web silk decorations may (i) act to attract prey, (ii) be decoys for predators, and (iii) make the web visible to prevent larger animals from destroying them. To disentangle the last two hypotheses, we examined the fleeing response and flight initiation distance (FID) of the Florida orb weaver spider (Argiope florida Chamberlin and Ivie, 1944). Spiders were approached in one of two manners: (1) a “predatory” one mimicking a bird and (2) a “looming” approach mimicking the approach of a large animal. We predicted that if silk decorations had an antipredator function, then the extent of silk decoration would influence whether spiders fled from the predatory approach. However, if the function was primarily a signal to large animals, then all spiders would flee the looming approach, but FID would be influenced by the extent of silk decoration. We found no influence of silk decorations on fleeing behaviour and FID of spiders. Spider fleeing behaviour was, however, influenced by height of the web from the ground. The effects of web height might reflect an adaptive response to a more exposed position and therefore could support either of the two hypotheses tested; however, we have no evidence supporting the role of silk decorations on antipredator responses.
Assembly and comparative analysis of transposable elements from low coverage genomic sequence data in Asparagales
Authors: Hertweck Kate L.
Published: May 2013

The research field of comparative genomics is moving from a focus on genes to a more holistic view including the repetitive complement. This study aimed to characterize relative proportions of the repetitive fraction of large, complex genomes in a nonmodel system. The monocotyledonous plant order Asparagales (onion, asparagus, agave) comprises some of the largest angiosperm genomes and represents variation in both genome size and structure (karyotype). Anonymous, low coverage, single-end Illumina data from 11 exemplar Asparagales taxa were assembled using a de novo method. Resulting contigs were annotated using a reference library of available monocot repetitive sequences. Mapping reads to contigs provided rough estimates of relative proportions of each type of transposon in the nuclear genome. The results were parsed into general repeat types and synthesized with genome size estimates and a phylogenetic context to describe the pattern of transposable element evolution among these lineages. The major finding is that although some lineages in Asparagales exhibit conservation in repeat proportions, there is generally wide variation in types and frequency of repeats. This approach is an appropriate first step in characterizing repeats in evolutionary lineages with a paucity of genomic resources.
OPTIMAL RECONFIGURABLE CONTROL FOR ADAPTIVE STRUCTURES WITH POLE CONSTRAINTS
Authors: ASHOKKUMAR CHIMPALTHRADI R.
Published: May 2013

Linear quadratic optimal regulator in multi-input setting exhibits several properties that are useful in adaptive control of structures. Its ability to preserve guaranteed stability margins in each input channel is particularly attractive to switch actuators, develop management schemes and meet the response tailoring objectives in the structure. A stabilizing controller for each of these actuators is already known from the regulator design. Since these controllers are infinite gain margin controllers, it is shown that they are also linear quadratic optimal with respect to a scalar multiplying the controller corresponding to the actuator. In this paper, these optimal controllers in a reconfigurable architecture are considered. Dynamic response tailoring by each actuator combination is investigated. Further, while switching actuators, parametric robustness of the reconfigurable systems is assessed with respect to the perturbed eigenvalues in a circular region. An oscillator model and a cantilever beam are used to illustrate the dynamic response tailoring in an adaptive structure using conventional and reconfigurable control principles.
ON SOME STANDARD GRADED ALGEBRAS IN MODULAR INVARIANT THEORY
Authors: PATTANAYAK S. K.
Published: May 2013

For a finite-dimensional representation V of a finite group G over a field K we denote the graded algebra R ≔ ⨁d≥0 Rd; where Rd ≔ ( Sym d∣G∣V*)G. We study the standardness of R for the representations [Formula: see text], [Formula: see text], and [Formula: see text], where Vn denote the n-dimensional indecomposable representation of the cyclic group Cp over the Galois field 𝔽p, for a prime p. We also prove the standardness for the defining representation of all finite linear groups with polynomial rings of invariants. This is motivated by a question of projective normality raised in [S. S. Kannan, S. K. Pattanayak and P. Sardar, Projective normality of finite groups quotients, Proc. Amer. Math. Soc.137(3) (2009) 863–867].
SIMPLE QUANTUM PROTOCOLS FOR THE MILLIONAIRE PROBLEM WITH A SEMI-HONEST THIRD PARTY
Authors: HE GUANG PING
Published: May 2013

Recently there were many quantum protocols devoted to solve the millionaire problem and private comparison problem by adding a semi-honest third party. They all require complicated quantum methods, while still leak a non-trivial amount of information to at least one of the parties. But it will be shown here that once the third party is introduced, there can be protocols which is very simple in the sense that they require quantum key distribution as the only quantum resource. Meanwhile, the amount of information leaked can be made arbitrarily small. Furthermore, in most previous protocols the third party can spoil the protocols without being detected. In our protocol such cheating can also be avoided, so that the only constraint left is that the third party should not conspire with another participant. Thus our solutions surpass all existing protocols on both feasibility and security.
Development and Flight Test Evaluations of an Autonomous Obstacle Avoidance System for a Rotary-Wing UAV
Authors: Kang Keeryun , Prasad J. V. R.
Published: May 2013

This paper presents the development and flight-testing of an obstacle avoidance system that can provide a rotary-wing unmanned aerial vehicle (UAV) the autonomous obstacle field navigation capability in uncertain environment. The system is composed of a sensor, an obstacle map generation algorithm from sensor measurements, an online path planning algorithm, and an adaptive vehicle controller. The novel approach of path planning presented in the paper is the integration of a newly developed receding horizon (RH) trajectory optimization scheme with a global path searching algorithm. The developed RH trajectory optimization scheme solves the local nonlinear trajectory optimization problem using approximated vehicle dynamics, maneuverability constraints, and terrain constraints within the finite range of the sensor. The global path searching by dynamic programming algorithm finds the shortest path to the destination to provide the initial guess to the RH trajectory optimization. The spline-based direct solver, Nonlinear Trajectory Generation (NTG), solves the RH trajectory optimization in real time and updates the solution continuously. The developed system is implemented within the Georgia Tech UAV Simulation Tool (GUST) and on the onboard computer of the Georgia Tech UAV test bed. Simulations and flight tests carried out for the benchmark scenarios and with sensor-in-the-loop flight tests demonstrated the viability of the developed system for autonomous obstacle field navigation capability of a UAV.
Cooperative Search and Exploration in Robotic Networks
Authors: Hu Jinwen , Xu Jun , Xie Lihua
Published: May 2013

Great potentials of robotic networks have been found in numerous applications such as environmental monitoring, battlefield surveillance, target search and rescue, oil and gas exploration, etc. A networked multi-robot system allows cooperative actions among robots and can achieve much beyond the summed capabilities of each individual robot. However, it also poses new research and technical challenges including novel methods for multi-agent data fusion, topology control and cooperative path planning, etc. In this paper, we review recent developments in cooperative control of robotic networks with focus on search and exploration. We shall first present a general formulation of the search and exploration problem, and then divide the overall search strategy into different modules based on their functions. Methods and algorithms are illustrated and compared following the classification of the modules. Moreover, a 3D simulator developed in our laboratory is introduced and its application is demonstrated by experiments. Finally, challenges and future research in this area are provided.
MuseUs
Authors: Coenen Tanguy , Mostmans Lien , Naessens Kris
Published: May 2013

This article describes a case study on MuseUs, a pervasive serious game for use in museums, running as a smartphone app. During the museum visit, players are invited to create their own exposition and are guided by the application in doing so. The aim is to provide a learning effect during a visit to a museum exhibition. Central to the MuseUs experience is that it does not necessitate a predefined path trough the museum and that it does not draw the attention away from the exposition itself. Also, the application stimulates the visitor to look at cultural heritage elements in a different way, permitting the construction of personal narratives while creating a personal exposition. Using a methodology derived from action research, we present recommendations for the design of similar applications and conclude by proposing a high-level architecture for pervasive serious games applied to cultural heritage.
An easy to author dialogue management system for serious games
Authors: Mori Daniele , Berta Riccardo , De Gloria Alessandro , Fiore Valentina , Magnani Lauto
Published: May 2013

This article describes an architecture for a dialogue management system to be employed in serious games for natural language interaction with nonplayer characters. The aim of this work is to improve the learning experience by enhancing the immersiveness felt by the player. The system is implemented in a Service Oriented Architecture perspective and it exposes its functionalities through Web services. It also provides an easy to use authoring tool, which allows cultural heritage experts to define the character's knowledge without the need for learning a scripting language. We tested the system by embedding it in a simple serious game, where the user could interact with the virtual representation of a XVI century Geneoese artist, Luca Cambiaso, in order to acquire knowledge about his life and artworks. These early lab test results showed a high level of appreciation for the usability of the system and for the user engagement. Tests also showed that the system is a good didactic tool, since players demonstrated a similar level of knowledge acquisition to that achieved by reading a text.
Proofs probable
Authors: Savage Neil
Published: May 2013

Shafi Goldwasser and Silvio Micali laid the foundations for modern cryptography, with contributions including interactive and zero-knowledge proofs.
Thumb numbers
Authors: Denning Peter J.
Published: May 2013

Rules of thumb stated as numerical rules are enticing, but many are folk theorems that may not apply in your critical situation.
Learning from the past to face the risks of today
Authors: Leveson Nancy G.
Published: May 2013

The Space Shuttle software program can provide guidance to today's projects.
Access to the internet is a human right
Authors: Wicker Stephen B. , Santoso Stephanie M.
Published: May 2013

Connecting Internet access with freedom of expression and creativity.
Incentives and rewarding in social computing
Authors: Scekic Ognjen , Truong Hong-Linh , Dustdar Schahram
Published: May 2013

Praise, pay, and promote crowd-member workers to elicit desired behavioral responses and performance levels.
Consequence analysis of complex events on critical U.S. infrastructure
Authors: Adam Nabil , Stiles Randy , Zimdars Andrew , Timmons Ryan , Leung Jackie , Stachnick Greg , Merrick Jeff , Coop Robert , Slavin Vadim , Kruglikov Tanya , Galmiche John , Mehrotra Sharad
Published: May 2013

How to mitigate a cyber-physical attack that disables the transportation network and releases a cloud of chlorine gas.
Puzzled: Solutions and sources
Authors: Winkler Peter
Published: May 2013

Last month (May 2013) we posed a trio of brainteasers concerning Ant Alice and her ant friends who always march at 1 cm/sec in whatever direction they are facing, reversing direction when they collide.
Predicting whether users view dynamic content on the world wide web
Authors: Jay Caroline , Brown Andy , Harper Simon
Published: May 2013

Dynamic micro-content—interactive or updating widgets and features—is now widely used on the Web, but there is little understanding of how people allocate attention to it. In this article we present the results of an eye-tracking investigation examining how the nature of dynamic micro-content influences whether or not the user views it. We propose and validate the Dynamic Update Viewing-likelihood (DUV) model, a CHi-squared Automatic Interaction Detector (CHAID) model that predicts with around 80% accuracy whether users view dynamic updates as a function of how they are initiated, their size, and their duration. The model is constructed with data from live Web sites and does not rely on knowledge of the user's task to make its predictions, giving it a high level of external validity. We discuss one example of its application: informing how dynamic content should be presented in audio via assistive technology for people with visual impairments.
Influence of personality on satisfaction with mobile phone services
Authors: Oliveira Rodrigo De , Cherubini Mauro , Oliver Nuria
Published: May 2013

We propose a conceptual model that explains the relationship between the users' personality profile and their satisfaction with basic mobile phone services (calls, messages, and simple GPRS/3G services). The model captures direct and indirect effects on satisfaction by means of two variables: actual mobile phone usage and perceived usability of the related services. We empirically validate the model with data gathered from 603 customers of a telecommunication operator, and find that: (1)
extroversion
,
conscientiousness
, and
intellect
have a significant impact on customer satisfaction—positively for the first two traits and negatively for the latter; (2)
extroversion
positively influences mobile phone usage; and (3)
extroversion
and
conscientiousness
positively influence the users' perceived usability of mobile services. Interestingly, usability has the strongest positive impact on satisfaction, whereas mobile phone usage has a negative impact on satisfaction. We discuss key findings of this model and propose several implications for the design of mobile phone services.
Negotiating food waste
Authors: Ganglbauer Eva , Fitzpatrick Geraldine , Comber Rob
Published: May 2013

Ecological sustainability is becoming of increasing concern to the HCI community, though little focus has been given yet to issues around food waste. Given the environmental impact of food waste, there is potential to make a significant difference. To understand everyday domestic practices around food and waste, we took a “practice” lens and carried out a study in 14 households that involved interviews, in-home tours and, in five of the households, a FridgeCam technology probe. The analysis highlights that food waste is the unintended result of multiple moments of consumption dispersed in space and time across other integrated practices such as shopping and cooking, which are themselves embedded in broader contextual factors and values. We highlight the importance of respecting the complex negotiations that people make within given structural conditions and competing values and practices, and suggest design strategies to support dispersed as well as integrated food practices, rather than focusing on waste itself.
A fuzzy model for high-level clones in software
Authors: Baliyan Niyati , Sharma Vidushi , Shivani
Published: May 2013

High-level similarities in software, referred to as High-Level Clones (HLCs) may manifest themselves as behavior clones, concept clones, collocated simple clones or domain model clones [3]. The presence of such similarities may deter the maintainability of software, while identifying them may improve the reuse, reengineering, evolution and understandability of software [2]. This study proposes an integrated measure of high-level cloning, using a four input fuzzy model. It also proves that the calculated extent of high-level cloning is practically equal to the simulation result in the MATLAB's fuzzy toolbox.
Mapping extended rationale diagrams to OLAP queries
Authors: N. Parimala , Kumar Ranjeet
Published: May 2013

We propose a method that enables decision makers to formulate OLAP queries. Firstly, the decision maker's analysis requirements are expressed as an extended rationale diagram. Subsequently, using the extended rationale diagram, we verify whether it is possible to get the information from the data warehouse. If it is, we generate the outline of the corresponding OLAP query. If it is not, we inform the user about the missing information.
Synthesis and Characterization of Nanosized (DyO1.5)x(WO3)y(BiO1.5)1-x-y for Lower Temperature SOFC Application
Authors: Lidie Ashley A. , Lee Kang Taek , Wachsman Eric D.
Published: May 2013

The high ionic conductivity (DyO1.5)x(WO3)y(BiO1.5)1-x-y (DWSB) material was synthesized using a coprecipitation method. Adding the acid solution containing Dy(NO3)3 and Bi(NO3)3 to the basic solution containing (NH4)10W12O41•5H2O, a DWSB precursor was formed. Upon calcination, nano-sized (DyO1.5)x(WO3)y(BiO1.5)1-x-y powder with the appropriate fluorite phase is generated. This nanopowder was incorporated into a composite cathode with La0.80Sr0.20MnO3-δ (LSM) using the glycine-nitrate process to coat the DWSB with the LSM. The two phases are mixed at the nano-scale and no reactivity between the two phases is observed. The ASR values for this cathode (0.17 Ω-cm2 at 600⁰C) is reduced by a half order of magnitude compared with the same composition mixed with solid state methods (0.45 Ω-cm2 at 600⁰C). Furthermore, the ASR values are significantly reduced from composite cathodes of LSM and common ionic conductors, namely LSM-GDC (1.3 Ω-cm2 at 600⁰C) and LSM-YSZ (1.5 Ω-cm2 at 600⁰C).
Investigation of Gadolinia-Doped Ceria (GDC) Electrolyte by Electrochemical Impedance Spectroscopy
Authors: Zhang Lei , Liu Feng , Brinkman Kyle , Virkar Anil V.
Published: May 2013

Electrochemical impedance spectroscopy (EIS) is widely used in the study of aqueous and solid state electrochemistry. Information such as sample conductivity and electrode effects can be studied by varying the frequency. Despite extensive use of EIS, two issues regarding the measurement and interpretation warrant discussion. They concern the high frequency inductive load and the use of constant phase element (CPE) for data fitting. The experimental work was conducted on polycrystalline gadolinia-doped ceria. In this work, subtracting lead impedance is shown to be an effective way to recover semi-circular behavior at high frequency, representative of grain boundary effects. The present work shows that in many instances for data interpretation, pure capacitance may be used in the equivalent circuit, instead of the often used CPE. The significance is that fitting can be achieved using one parameter rather than two needed for CPE.
Dispersion of Oleate-modified CeO2 Nanocrystals in Non-Polar Solvent and Aqueous Solution
Authors: Kobayashi Katsutoshi , Haneda Masaaki , Ozawa Masakuni
Published: May 2013

Oleate-modified CeO2 nanocrystals with the size of 2-7 nm were synthesized by a hydrothermal treatment. Characterization of the nanocrystal was performed by XRD, TEM, and IR analyses. Dispersion states of the hydrophobic CeO2 nanocrystals were investigated in toluene and several types of alkaline aqueous solution such as KOH, TMAH, and ammonia solution, and different dispersion modes were observed. Toluene and strongly basic aqueous solution gave excellent transparent dispersion liquids, while the weakly basic solution resulted in the turbid dispersion indicating the formation of large micelles. The particle-size distribution measurement by the DLS method and the surface-potential measurement suggested the dispersion mechanism of CeO2 nanocrystals and clarified the micelle formation process in aqueous solution.
Electrical Performance of La-Substituted SrTiO3 Anode Material with Different Deficiency in A-Site
Authors: Chen Gang , Kishimoto Haruo , Yamaji Katsuhiko , Kuramoto Koji , Horita Teruhisa
Published: May 2013

Performance of (La0.25Sr0.75)1-xTiO3
(LST) with different deficiency (x) in A-site and the effect of A-site deficiency on the interfacial reaction between LST anode and 1CeO2-10Sc2O3-89ZrO2 (ScSZ) electrolyte were investigated. According to the results of XRD and SEM of LSTs with different deficiency, a maximum value of x (between 0.1 and 0.15) for single phase LST was found to be existed in LST. La2Zr2O7 (LZO) was found to be formed at the interface of ScSZ and stoichiometric LST or LST with little deficiency in A-site. A-site deficiency in LST could suppress the interfacial reaction between LST and ScSZ. The performance of the cells with A-site deficient LST anode was increased as the value of A-site deficiency in LST increased.
Ultra Small Angle X-ray Scattering Studies of Solid Oxide Fuel Cell Cathode Powders
Authors: Chang Kee-Chul , Ingram Brian , Hopper Mitch , Ilavsky Jan , You Hoydoo
Published: May 2013

We demonstrate the feasibility of using Ultra Small Angle X-ray scattering to study cathode structures in solid oxide fuel cells (SOFC) under operating conditions. Cathode thickness has been optimized and symmetric SOFC test structures have been characterized. We also demonstrate that we can follow the evolution of microstructure on a La0.6Sr0.4Co0.2Fe0.8 infiltrated yttria stablized zirconia backbone structure under annealing, showing the viability of characterizing multi-scale cathode structures in real time.
Cathode Performance and Deposited Cr under Cr Poisoning Condition in the (La0.6Sr0.4)(Co0.2Fe0.8)O3 Cathode
Authors: Cho Do-Hyung , Kishimoto Haruo , Brito Manuel E. , Yamaji Katsuhiko , Nish MIna , Shimonosono Taro , Wang Fangfang , Yokokawa Harumi , Horita Teruhisa
Published: May 2013

The Cr poisoning behavior of LSCF6428 cathode was investigated under Cr containing vapor conditions at 1073 K using LSCF6428/GDC/Pt cells. Under a cathodic polarization of - 200 mV, cathode current decreased by supplying of Cr containing vapor. From the AC impedance, a significant increase of the polarization resistance (low frequency contribution) was observed during cell tests. Post-analysis of operated samples showed that a thick SrCrO4 layer was formed on the surface of LSCF cathode and a small amount of SrCrO4 was found inside. From the long- term operated sample (380 h), pore-like dark spots were confirmed in LSCF grains. Correlation between LSCF cathode performance and deposited Cr was deduced from change of polarization resistance and the amount of deposited Cr (Cr/La ratio) in LSCF cathode.
Influence of Water Vapor on Sulfur Distribution Within La0.6Sr0.4Co0.2Fe0.8O3 Cathode
Authors: Wang Fangfang , Yamaji Katsuhiko , Cho Do-Hyung , Shimonosono Taro , Nishi Mina , Kishimoto Haruo , Brito Manuel E. , Horita Teruhisa , Yokokawa Harumi
Published: May 2013

Effects of water vapors on the sulfur poisoning behavior ofLSCF6428 cathode were investigated by comparison inperformance and impedance spectroscopic results ofLSCF6428/10GDC cells, which were tested at 1073 K (800 oC) for100 h under two conditions: (a) 1 ppm SO2 with dry air and (b) 1ppm SO2 with 1.2% humidified air. Results of performancedegradation with impedance spectroscopic data revealed that thespeed for rather heavy degradation is accelerated about 10 times inthe presence of water vapor. Detailed analyses on post-test sampleshow that the amount of formed SrSO4 during the same operationtime is much larger in the humidified air.
Correlation between Protonic Conductivity and Structure of Phosphate Glasses for Intermediate Temperature Fuel Cells
Authors: Sumi Hirofumi , Fujishiro Yoshinobu , Oine Takahiro , Kasuga Toshihiro
Published: May 2013

We measured NMR, Raman spectra and AC impedance for BaO-ZnO-P2O5 glasses. The short-range order of these glasses was based on metaphosphate (Q
P
2) structure. A part of O-P-O bonding was broken and the mobile proton concentration increased for ternary BaO-ZnO-P2O5 glasses. The protonic conductivity was 2 × 10-7 S/cm for 30 mol%ZnO-10 mol%BaO-60 mol%P2O5 glass at 200 oC. Co-doping of the cations with different coordinate numbers is effective to improve the protonic conductivity for phosphate glasses.
High Proton Conductivity in Anodic ZrO2–WO3–SiO2 Nanofilms
Authors: Ye Ke , Aoki Yoshitaka , Tsuji Etsushi , Nagata Shinji , Habazaki Hiroki
Published: May 2013

The proton conductivity of the anodic ZrO2–WO3–SiO2 nanofilms prepared by anodizing of sputter-deposited Zr37W47Si16 alloy at several formation voltages for 1.8 ks in 0.1 mol dm−3 phosphoric acid electrolyte at 20oC has been examined below 250oC in various environments. The proton conductivity activated by thermal treatment at 250oC is not influenced by the presence of O2 and H2O in the atmosphere. However, the conductivity is enhanced by one order of magnitude in H2-containing atmosphere. The H2-induced conductivity enhancement is reversible; the enhanced conductivity is returned to an original value by exposing again in an O2-containing atmosphere.
Hf Cap Thickness Dependence in Bipolar-Switching TiN\HfO2\Hf\TiN RRAM Device
Authors: Chen Yang Yin , Pourtois Geoffrey , Clima Sergiu , Goux Ludovic , Govoreanu Bogdan , Fantini Andrea , Degreave Robin , Kar G. S. , Groeseneken Guido , Wouters Dirk J. , Jurczak Malgorzata
Published: May 2013

In this work, the influence of Hf cap thickness of bipolar resistive switching in TiNHfO2HfTiN resistive random access memory (RRAM) stack was investigated. More stable bipolar switching and longer endurance were achieved by increasing the Hf cap thickness from 2nm to 10nm. First-principle simulation suggested more oxygen vacancies (Vox) generation for thicker Hf cap. Lower FORMING voltage from thicker Hf cap devices confirms more Vox generation in the stack. X-ray photoelectron spectroscopy (XPS) also physically detected more oxygen scavenge from HfO2 bulk by thicker Hf cap. The more generated Vox in thicker Hf cap stack probably accounted for the improved bipolar switching properties.
(Invited) Analysis of the Scaling Effect on NAND Flash Memory Cell Operation
Authors: Shirota Riichiro , Watanabe Hiroshi
Published: May 2013

In recent years, the enormous success of NAND Flash memory technology in realizing multi-gigabyte memory chips has evidently triggered a lot of difficulties concerning its cell operation, such as parasitic neighbouring cell coupling, FN-tunnelling statistics, Vt distribution widening by RTN, et al. In this paper, two kinds of phenomena are shown. One is the increase of the interface state density after write/erase cycles, which will degrades the sub-threshold swing (SS) of the memory cell in the NAND string. The other is the increase of the programmed Vt distribution after programming, which also reduces the cell operation margin. It is revealed that Vt distribution widening is closed depends on the floating gate doping concentration of Phosphorus. These phenomena become more serious as cell size smaller.
Characteristics of Nano-Crystalline Ge2Sb2Te5 Material for Phase Change Memory
Authors: Ohyanagi Takasumi , Takaura Norikatsu
Published: May 2013

We report nano-crystalline Ge2Sb2Te5 (GST) with nano-meter-sized GST crystals. The transition temperature from amorphous to crystalline state was improved compared to that of non-doped and SiO2-doped GST. Structure analysis was conducted by transmission electron microscopy (TEM) and x-ray absorption fine structure (XAFS) spectroscopy.
Electrical Properties of Sol-Gel Derived PbLaZrTiOx Capacitors with Nonnoble Metal Oxide Top Electrodes
Authors: Takada Yoko , Tsuji Toru , Okamoto Naoki , Saito Takeyasu , Kondo K. , Yoshimura Takeshi , Fujimura Norifumi , Higuchi Koji , Kitajima Akira , Oshima Akihiro
Published: May 2013

PbLaZrTiOx(PLZT) thin films were fabricated on Pt(111) substrateby the sol-gel method for ferroelectric capacitors. Pt top electrodeswere deposited by sputtering, aluminum-doped zinc oxide (AZO)or indium tin oxide (ITO) top electrodes were deposited by pulsedlaser deposition (PLD) on PLZT capacitors. We compared bothdegradation characteristics by annealing in 200°C, 1Torr, 3%hydrogen atmosphere and fatigue properties, exhibited the PLZTcapacitors with AZO and ITO top electrodes has better propertiescompared to the PLZT capacitors with Pt top electrodes.
Electric Conduction Mechanism of Resistive Switching Memory Fabricated with Anodic Aluminum Oxide
Authors: Otsuka Shintaro , Shimizu Tomohiro , Shingubara Shoso , Iwata Nobuyuki , Watanabe Tadataka , Takano Yoshiki , Takase Kouichi
Published: May 2013

The electric conduction mechanism of electrochemically treated anodic porous alumina (APA) resistance switching (RS) memory is investigated. The current-voltage characteristics of the APA were measured for both of high resistance state and low resistant state at room temperature. The conduction mechanism of a high resistance state can be explained by separating into three regions of Ohm's law, space charge limited current (SCLC), and Fowler-Nordheim (F-N) tunneling. It was suggested that the F-N tunneling decreases the reproducibility of switching voltages.
Pulse Switching Property of Reset Process in Resistive Random Access Memory (ReRAM) Consisting of Binary-Transition-Metal-Oxides
Authors: Moriyama Takumi , Kinoshita Kentaro , Koishi Ryosuke , Kishida Satoru
Published: May 2013

For high speed switching of ReRAM, we must elucidate a dominant parameter to control switching speed for a reset process (t
reset). Since t
reset is not necessarily determined by only one parameter, we proposed a method to get reset parameters which are expected to be related to t
reset, low resistance, applied voltage and filament temperature (T
reset), from a same experimental data. The estimated reset parameters of Pt/NiO/Pt structures show that t
reset is dominantly dependent on T
reset, considering the direction of oxygen ions migration in set and reset processes. A possibility that T
reset was underestimated due to decrease in resistance of NiO surrounding the neighborhood of filament by Joule heating was discussed.
Fabrication of a Vertical Nanogap for Nonvolatile Memories
Authors: Furuta Shigeo , Masuda Yuichiro , Takahashi Tsuyoshi , Ono Masatoshi , Naitoh Yasuhisa , Shimizu Tetsuo
Published: May 2013

As one of the candidates of a next-generation memory, we study the memory element using resistance change of the metal nanogap. Since this element has many advantages, for example, quite simple structure, wide material selectivity, high-speed programing, and high temperature tolerance. In this report, to realize miniaturization and mass production, vertical type nanogap elements were developed. As a result of measurements, the characteristic of vertical type is better than the element of lateral type. We studied switching speed of the elements and confirmed that the switching speed is under 50 ns.
(Invited) Application of Ordered Intermetallic Phases to Electrocatalysis
Authors: Matsumoto Futoshi , Saravanan Govindachetty , Kobayashi Genki
Published: May 2013

We present here the results of the oxidation of formic acid (FA) at various constant electric potentials on ordered intermetallic PtPb nanoparticles(Nps), their tolerance toward carbon monoxide (CO), and their details about oxidative mechanism. Relatively stable and higher FA oxidation current density was observed for 20 h in an aqueous solution of sulfuric acid, whereas the oxidation current of FA rapidly decreased on commercially available Pt and Pt-Ru alloy Nps. In addition, PtPb Np surfaces showed no CO-stripping oxidation current due to a negligible and/or no irreversible adsorption of CO onto the PtPb Nps. The oxidation of FA on PtPb Nps does not generate CO molecules as intermediate poisoning species, confirmed by electrochemical impedance spectroscopy.
Durable Oxide-Based Catalysts for Application as Cathode Materials in Polymer Electrolyte Fuel Cells (PEFCs)
Authors: Rabis Annett , Fabbri Emiliana , Foelske A , Horisberger Michael , Kötz Rüdiger , Schmidt Thomas J.
Published: May 2013

The goal of this work is the development of new oxide based highly active model catalysts for the oxygen reduction reaction in PEFCs. In this work, a description for the preparation of SnO2 thin films by reactive magnetron sputtering is given. The films are characterized using x-ray diffraction, x-ray photoelectron spectroscopy and electrochemical measurements. Composition and high potential stability of the SnO2 films was proven before its use as substrates for Pt model electrodes. Oxygen reduction kinetics on Pt/SnO2 demonstrates similar activities as compared to typical carbon based systems, an important prerequisite for further studies and development of SnO2 based electrocatalysts.
One-Step Electrodeposition of Multilayered Surfactant/MnO2 Composite and Its Electrochemistry
Authors: Shamoto Mitsuhiro , Mito Shunsuke , Tomono Kazuaki , Nakayama Masaharu
Published: May 2013

Multilayered manganese dioxide film intercalated with surfactant molecules was synthesized by anodic oxidation of aqueous Mn(II) ions in the presence of cetyltrimethylammonium (CTA) ions. Ion-exchange and electrochemical properties of the CTA/MnO2 nanocomposite were examined in different electrolytes (Na2SO4, sodium dodecylsulfate (NaDS), sodium benzenesulfonate (NaBS), and dodecyltrimethylammonium chloride. CTA+ cations that were incorporated between MnO2 layers during electrodeposition were not ion-exchanged with Na+ in solution, probably as a result of hydrophobic interaction between their long alkyl chains. According to XPS analysis, cationic head groups of the surfactants were coupled with not only negative charges on MnO2 layers but also Cl- anions. These Cl- anions were readily replaced with SO4
2- and BS-, which means installation of anion exchange sites in the interlayer. Only in NaBS electrolyte, the CTA/MnO2 film provided a good electrochemical response without releasing the CTA+ ions, where the electroneutrality of the film was maintained by Na+ ions.
ORR Activity Enhancement of MBE-Prepared Pt Monolayer on Au Single-Crystal Substrate
Authors: Iijima Yuki , Takahashi Yu , Matsumoto Ken-ichi , Todoroki Naoto , Wadayama Toshimasa
Published: May 2013

Oxygen reduction reaction (ORR) activities of Pt/Au(111) and Pt/Au(100) bimetallic surfaces prepared using molecular beam epitaxy were evaluated in this study. Surface structures of the bimetallic surfaces were verified using a scanning tunneling microscope under ultra-high vacuum conditions. The deposition of a 0.3-nm-thick Pt on a clean Au(111) at 300 K (300K-Pt0.3nm/Au(111)) generated a corrugated Pt(111) epitaxial layer on which monoatomic-height Pt islands are present. The ORR activity estimated from the kinetically controlled current density at 0.9 V vs. RHE was ca. two times greater than that of the clean Pt(111). In contrast, the 473K-Pt0.3nm/Au(111) as well as 300K-Pt0.3nm/Au(100) exhibited small hydrogen-related charges, thereby were less ORR active than the corresponding clean Pt substrate surfaces. These results suggest that atomic arrangements of surface Pt atoms, particularly the morphologies of the most dense plane of Pt(111), correlate with the enhancement in the ORR activity of Pt–Au bimetallic nanoparticles.
Redox Properties and Catalytic Activity for Oxygen Reduction Reaction of Electropolymerized Aromatic Diamines
Authors: Kishioka Shin-ya
Published: May 2013

Electrochemical polymerization of 2,3-diaminophenazine (2,3-DAP) was carried out in an acidic aqueous solution and in anacetonitrile solution. While the redox property of poly(2,3-DAP)deposited in acidic aqueous solution indicated rather complicatedcurrent-potential response, poly(2,3-DAP) deposited in acetonitrileshowed simple wave shape. Catalytic activity of both poly(2,3-DAP)s for oxygen reduction reaction was compared to that ofpoly(o-phenylenediamine) using cyclic voltammetry.
Photoelectrochemical Hydrogen Generation and Concomitant Organic Dye Oxidation under TiO2 Nanotube
Authors: Zanoni Maria Valnice Boldrin , Guaraldo Thais
Published: May 2013

Highly ordered TiO2 nanotube has been widely employed as photoanode for degradation of organic compounds oxidation during photoelectrochemical process, but its capacity to form hydrogen is not explored. The present work describes the degradation of reactive black 5 dye used as a model of organic pollutant at TiO2 nanotube electrode and concomitant generation of hydrogen at the cathode. A two compartment cell (25mL each compartment) with 0.1 mol L-1 Na2SO4 medium was used and the TiO2 nanotube was photoactivated with UV light using 150W Xe-Arc lamp (Oriel) under bias potential. All photoelectrochemical measurements were carried out in a potenciostat Autolab PGSTAT 302 using a Pt gauze as cathode and as reference electrode a Ag/AgCl. Dye degradation was monitored by spectrophotometric and TOC measurements and hydrogen generation monitored by volume and gas chromatography analysis. The influence of parameters like concentration, pH of the cathode and anode and applied potential was investigated. Using the best experimental conditions of 5x10-5 M dye in 0.1 M Na2SO4 M pH 6, E= 1.0 V and UV irradiation it was obtained 100% of color removal and 72% of TOC removal. Simultaneously was 44% of hydrogen efficiency after 2 h of photoelectrolysis.
Composite Thin Film Iridium- Niobium Oxide Electrocatalysts for the Oxygen Evolution Electrode
Authors: Zlotorowicz Agnieszka , Seland Frode , Sunde Svein
Published: May 2013

A series of (IrO2)1-x(Nb2O5)x catalyst with Nb2O5 loading from 0.1-0.7 mol% was prepared by hydrolysis method and annealed at 500 ºC. Electrodes of the catalyst powder was characterized in 0.5 mol dm−
3 H2SO4 by cyclic voltammetry (CV) and quasi steady-state polarisation measurements (LSV). X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) indicated a phase separation into iridium oxide and niobium pentoxide in the catalyst for all compositions and forms composite oxide rather than a solid solution. In line with this, at room temperature the catalytic activity decreased with increasing niobium content in the catalyst. However, raising the temperature to 80 oC inverted this sequence so that the catalytic activity increased in the order IrO2 < (IrO2)0.7(Nb2O5)0.3 < (IrO2)0.9(Nb2O5)0.1.
Investigation of Ion Dependence of Electronic Structure for 3d3 Ions in Mg2TiO4 Based on First-Principles Calculations
Authors: Novita Mega , Yoshida Hisashi , Ogasawara Kazuyoshi
Published: May 2013

In this work, the local electronic structures around isoelectronic 3d
3 ions such as V2+, Cr3+, and Mn4+ in Mg2TiO4 crystals were investigated based on first-principles configuration-interaction calculations. The factors to determine tendencies of the crystal field splitting and the multiplet energy among them were analyzed in detail based on the explicit many-electron wave functions. The multiplet energy levels of V2+, Cr3+, and Mn4+ doped in Mg2TiO4 were calculated using the discrete variational multi-electron code, which is a configuration-interaction calculation program based on the discrete variational-Xα method. Overall, the results show that only the calculation with consideration of the lattice relaxation effect can provide a reasonable tendency, where the multiplet energies of 4A2 → 4T2 (U-band) and 4A2 → 4T1a (Y-band) increase as the charge of the transition metal ion increases.
Electroluminescence from Cr3+ in Perovskite Thin-Film Phosphors Using LaAlO3 and LaGaO3 as Hosts
Authors: Miyata Toshihiro , Nishi Yuki , Mori Takayuki , Abe Shinya , Minami Tadatsugu
Published: May 2013

We observed multicolor and near-infrared electroluminescence (EL) from perovskite oxide thin-film phosphors using Cr- and Ce-co-doped LaGaO3 and LaAlO3. These phosphor thin films were prepared by varying either Cr or Ce content using a combinatorial r.f. magnetron sputtering deposition method. Intense deep-red and weak yellow-green EL emissions were observed from thin-film electroluminescent (TFEL) devices fabricated using posannealed LaGaO3:Ce,Cr thin films. Intense near-infrared emission and yellow-green EL emissions were observed from TFEL devices fabricated using posannealed LaAlO3:Ce,Cr thin films. The highest EL intensity was obtained in TFEL devices using postannealed LaGaO3:Ce,Cr and LaAlO3:Ce,Cr phosphor thin films with Cr content approximetly 3 and 1at.%, respectively. All the observed emission peaks in EL from the LaGaO3:Ce,Cr and/or the LaAlO3:Ce,Cr phosphor thin films were assigned to either the emission originating from the transition in the Ce3+ and Cr3+ ions.
Fast Luminescence in Silicon-Germanium Nanostructures
Authors: Lockwood David J. , Wu Xiaohua , Baribeau Jean-Marc , Modi Nikhil , Tsybeskov Leonid
Published: May 2013

Epitaxially-grown three-dimensional Si/SiGe nanostructures produce photoluminescence and electroluminescence in the desired spectral range of 1.3-1.6 μm. We show that by controlling and modifying such Ge-rich SiGe nanoclusters during growth it is possible to fabricate very fast and hence more efficient SiGe light-emitting devices. The physics of carrier recombination in these Si/SiGe nanostructures is discussed. The present results provide another possible route toward CMOS compatible light emitters.
XANES and XES Studies of Luminescent Silicon Carbonitride Thin Films
Authors: Khatami Zahra , Wilson Patrick Robert James , Wojcik Jacek , Mascher Peter
Published: May 2013

We investigated the photoluminescence (PL) and electronic properties of both undoped and doped silicon carbonitride (SiCN) thin films, fabricated using electron cyclotron resonance plasma enhanced chemical vapor deposition (ECR PECVD). The PL intensity of SiCN films is highly dependent on the annealing temperature and doping condition with rare-earth metals. Notably, Ce+3- and Tb+3-related luminescence were observed from doped samples after being annealed in nitrogen ambient at 1200°C for one hour. The electronic characteristics of these doped and un-doped films were analyzed using soft X-ray absorption near edge structure (XANES) and X-ray emission spectroscopy (XES) measurements, showing significant structural re-ordering occurs as the annealing temperatures were increased.
Comparative Study of Using Chlorine and Hydrogen Chloride for Synthesis of Titanium Carbide Derived Carbon
Authors: Tallo Indrek , Thomberg Thomas , Jänes Alar , Lust Enn
Published: May 2013

For the synthesis of carbide derived carbons molecular chlorine is dominantly used, but hydrogen chloride is also mentioned as a reagent. There is however no thorough investigation whether the resulting carbon is comparable or distinct using different gases for halogenation of carbides. Different titanium carbide derived carbon powders were synthesized from titanium carbide within the temperature range from 700 to 1100°C either using molecular chlorine or hydrogen chloride as reactants. High-resolution transmission electron microscopy, X-ray diffraction and Raman spectroscopy analysis were carried out to investigate the structure of the synthesized materials. The electrochemical characteristics of the supercapacitors based on the synthesized carbon electrode materials have been tested using cyclic voltammetry, constant power and electrochemical impedance methods. Based on experimental results, titanium carbide derived carbon materials synthesized by using molecular chlorine can be considered superior over those materials that have been synthesized using hydrogen chloride.
Nitrogen Doped Graphene as a High Efficient Electrode for Next Generation Supercapacitors
Authors: Chabot Victor , Hassan Fathy Mohamed , Yu Aiping
Published: May 2013

This study reports the preparation of nitrogen doped graphene (NG) by hydrothermal synthesis. The morphology, structure, and composition of the prepared NG were confirmed with SEM, XRD, XPS and Raman spectroscopy. The material was tested for supercapacitive behavior. Our emphasis here is focused on the method of synthesis as an energy saving process, compared to other methods utilizing high temperatures or plasma techniques. The results confirmed that 2.77% nitrogen was chemically doped to graphene. Furthermore, it was found that doping with nitrogen increased the supercapacitance of graphene by 45%, reaching 131 F/g. An equivalent two electrode cell fabricated from NG material could provide energy density as high as 4.55 Wh/kg and a stable average power density of 2.46 kW/kg.
Dramatic Improvements in Electric Double-Layer Capacitors by Using Polysaccharides
Authors: Yamagata Masaki , Ikebe Shota , Kasai Yuki , Soeda Kazunari , Ishikawa Masashi
Published: May 2013

A nonaqueous solid-state electrolyte based on an alginate (Alg) with a conventional supporting electrolyte was prepared for use in electric double layer capacitors (EDLCs). According to the charge/discharge measurements, despite the use of a solid-state electrolyte, the model EDLC cells containing the Alg-based electrolyte possessed a higher discharge capacitance than the corresponding solution-based electrolyte, which implies that the high affinity of Alg for activated carbon electrodes decreases the electrode/electrolyte interfacial resistance. Because of its good affinity for carbon materials, we also applied Alg as a binder to an activated carbon-based composite electrode. The test cells with the composite electrodes containing Alg demonstrated a remarkably powerful EDLC performance using both a conventional organic-solution-based electrolyte and a highly viscous ionic liquid electrolyte.
Temperature effects in Activated Carbon Supercapacitors
Authors: Kirk Donald W. , Graydon John W , Klas Sivan
Published: May 2013

Supercapacitors are energy storage devices that have the ability to be charged and discharged much faster than batteries but suffer from low energy density. In researching the influence of pore dimensions of activated carbon to increase energy storage, we reported earlier that there can be a significant fraction of charge held in activated carbon that has a very long redistribution time constant, at least for the carbon source with which we were working. This implies that the energy density could be increased if we can understand the reasons for charge redistribution. In this paper, the research has been extended to include other commercial carbon sources and similar charge redistribution phenomenon has been found. The effect of temperature has been studied to understand the phenomenon of charge redistribution in activated carbon supercapacitors.
Cathodic Synthesis of Birnessite Films for Pseudocapacitor Application
Authors: Tanimoto Takahiro , Abe Hikaru , Tomono Kazuaki , Nakayama Masaharu
Published: May 2013

Cathodic reduction of an aqueous solution of potassium permanganate in the presence of various alkaline metals except for Na+ ions led to a deposition of birnessite-type layered MnO2. Thehighest crystallinity was achieved in a bath containing 2 mMK MnO4 and 50 mM KCl by applying a constant potential of 0 V vs Ag/AgCl. The cathodic formation of birnessite was prevented by the presence of divalent cations, and Na+ ions yielded an amorphous or low crystalline product. The birnessite film thus formed showed excellent pseudocapacitive characteristics in its as-deposited state; i.e., a specific capacitance as high as 322 F g-1 at a potential scan rate of 2 mV s-1, which is much higher than that (75F g-1) of the birnessite film prepared anodically from Mn2+ ions.