bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dissociative Adsorption of O2 on Clean and CO-Precovered Pt Surfaces
Authors: Shan Bin , Wang Ligen , Hyun Jangsuk , Sang Yang , Zhao Yujun , Nicholas John B 
Published: April 2011

ABSTRACTIt is generally accepted that CO oxidation on transition metals follows a Langmuir-Hinshelwood mechanism. The oxidation reaction takes place in two sequential steps where the oxygen molecule first dissociates into atomic oxygen and then reacts with an adsorbed CO to form CO2. One critical question concerning the reaction kinetics under high pressure is the probability of oxygen dissociation on a highly CO covered surface. On bare transition metal surfaces, molecularly adsorbed oxygen readily dissociates with little or no apparent activation barrier. In industrial diesel engine catalysis, the metal surface is initially packed with CO. Subsequent reactions such as oxygen dissociation must take place on a CO covered surface. In this paper, we performed density functional theory (DFT) calculations for O2 dissociation on Pt(111) in the presence of different CO adsorption environments. While several stable O2 molecular precursor states (top-bridge-top, top-fcc-bridge, and top-hcp-bridge) exist on a clean Pt(111) surface, these precursors become endothermic beyond a critical CO coverage of ∼0.44 ML. Furthermore, the reaction path for CO oxidation via dissociated atomic oxygen becomes less favorable at higher CO coverage, primarily due to competitive adsorption and lateral repulsion. It was found that the oxygen dissociation barrier and the binding energies of atomic oxygen are well correlated via the Evans-Polanyi relationship.
QMC Assessments of Weak-interaction Described by DFT within various XC approximations / Effects of Carbon Nanotube Oxidation on Molecular Interactions
Authors: Kanai Yosuke , Grossman Jeffrey C. 
Published: April 2011

ABSTRACTThis paper first presents the fixed-node diffusion and reptation quantum Monte Carlo (QMC) assessment of density functional theory (DFT) description of weak molecular interactions within several exchange-correlation (XC) approximations. The case of Benzene-molecule complex was studied with a number of small molecules. We found that the binding energy for the set of complexes depend significantly on XC approximation employed although its trend appears rather consistent. Analysis of the reduced density gradient revealed that the binding energy trend among different XC approximation is highly correlated with the exchange enhancement factor behaviors at large reduced density gradients. Our findings point to the importance of accurate exchange energy functional in describing the weak interactions, in addition to the more obvious correlation part in DFT description.We then present DFT investigation on molecular interaction of NO3 toward a single-wall carbon nanotube (CNT). We aim to explain the atomistic processes that are responsible for the recently observed CNT conductance changes in the redox process. We found that molecular physisorption and chemisorption to be energetically stable states, and the chemisorbed configuration becomes less endothermic with an increased oxidation state of the CNT. Our results also show that the dissociative incorporation of the molecule can become highly favored energetically in the process. This chemical state may play an important role of the occasionally-observed CNT conductance irreversibility in the experiment.
Additivity of Hardening by Nanolamellar Structure and Antiphase Domain in Ti-39at%Al Single Crystals
Authors: Koizumi Yuichiro , Minamino Yoritoshi , Tanaka Takayuki , Iwamoto Kazuki 
Published: April 2011

AbstractA mixed microstructure of antiphase domains (APD) and fine lamellar structure were introduced in a Ti-39at%Al single crystal and it was examined whether the APD hardening works even in nano-scaled lamellar structures. The hardness increases with decreasing APD size even where the L is smaller than 100 nm below which the hardening by lamellar refining saturates. The mechanism of the additivity of strengthening by APD and lamellar structure is discussed in the context of the geometries of slip direction, lamellar boundaries and APD boundaries (APDBs). For {1100}<1120> prism slip (the easiest slip system of α2-Ti3Al), the lamellar boundaries are parallel to the slip direction, and therefore they interrupt the motion of screw dislocations effectively. On the other hand, APDBs inclined from lamellar boundaries can effectively obstruct the dislocation motion regardless of the dislocation character because the shear of such APDBs results in the formation of step-like APDBs on the slip-plane and requires additional stress for dislocation motion whereas APDBs parallel to the slip direction can be sheared without forming such a step-like APDB. Accordingly, APDs and lamellar structure can contribute to the strengthening complementarily.
DNA - Directed Synthesis of ZnO Nanowires
Authors: Jost Micha , Atanasova Petia , Gerstel Peter , Sigle Wilfried , van Aken Peter A. , Bill Joachim 
Published: April 2011

AbstractIn this paper, a new and simple method for the synthesis of ZnO nanowires under very mild conditions is presented. The nanowire preparation is based on mineralization from alkaline aqueous zinc nitrate solution in the presence of fish sperm DNA as a structure-directing agent. The morphological features of the obtained structures were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), while the structural characterization of ZnO was done by X-ray diffraction.
Microstructure Characterization Of Calcified Tissues By Xrd Using An Area Detector
Authors: Rodriguez-Navarro Alejandro , Checa Antonio G. 
Published: April 2011

AbstractOrganisms can precipitate a wide array of minerals which they use to build calcified tissues (i.e., bone, mollusk shell, eggshell, coccolith) having highly sophisticated microstructures. The disposition of organic and mineral components building these materials is highly organized from the nano- to the millimeter scale. Their ordered assembly implies self-organization processes accorded in space and time, giving rise to highly sophisticated textured materials. The objective of our work is the study of fundamental processes in biomineralization such as self-organization processes and texture control in biomineral crystal aggregates. To study the order in the arrangement of shell making crystals we used area detectors available today in modern X-ray diffractometers. The 2D diffraction patterns, collected using such detectors, contain detailed information not only about the mineralogy but also about the microstructure characteristics of polycrystalline materials – crystal size, stress, crystallinity and crystallographic-texture. For instance, to understand microstructure development in mollusk shells, we use this type of detector to do microdiffraction analyses combined with high resolution SEM in order to follow the ordering mechanisms of crystals making these biomaterials.
A Comparative Analysis of Iridium Oxide Nanowires in Electrical Detection of Biochemical Reactions
Authors: Venkatraman Vinu , Reddy Ravikiran , Zhang Fengyan , Evans David , Hsu Sheng-Teng , Ulrich Bruce , Prasad Shalini 
Published: April 2011

AbstractPt, Ir, Au and few other precious metals have highly conducive electrical and chemical properties; hence have been widely used in pH sensors and bimolecular sensing applications. The chief objective of this research is to highlight and demonstrate the advantages that Iridium Oxide (IrOx) nanowires offer over these competing metals in improving the performance metrics of biomolecular sensing. Iridium oxide has very good conductivity and very high charge storing capacity, and hence has an ability to detect very small changes in the surface charge. Nanowires have an ideal morphology to crowd protein molecules and highly increase the surface area of interaction. Higher area of interaction along with iridium oxide's high intrinsic physical adsorption rate, strongly enhance the rate of immobilization of biomolecules and hence enabling high sensitivity detection. Inflammatory protein, C-Reactive protein (CRP) that is a biomarker for cardiovascular disease was used as the model biomolecule for this study.
Experimental Research on Thermal Energy Storage of a New Type of PCM Heat Exchanger
Authors: Xiaoqin Zhu , Jin Hu , Nanjing Li , Panpan Wang , Jiansheng Lu , Ben-Abdallah Noureddine 
Published: April 2011

AbstractThermal energy storage with phase change materials is one of the most efficient means of storing available energy because of its advantages such as providing higher thermal storage capacity, lower storage temperature, isothermal operation and less storage space. Thermal energy storage property of a new type of PCM heat exchanger was investigated, in which its main body is based on the traditional structure of a shell-and-tube heat exchanger, and is full of PCMs (CaCl2·6H2O) in the tubes. The hot air at the temperature of 40° was selected as a flow medium, and the temperature measurements of the test points were carried out at the inlet and outlet of this kind of PCM heat exchanger. The experimental results showed that this kind of PCM heat exchanger could store thermal energy from the hot fluid by means of PCMs in the tubes. Its prospect in engineering applications such as the recovery and utilizations of industrial afterheat or waste heat etc was also analyzed and forecasted.
Review on Development and Investigations of Phase Change Materials in Thermal Energy Storage
Authors: Xiaoqin Zhu , Jin Hu , Zhaosheng Cao , Jiansheng Lu , Jialin Sun , Ben-Abdallah Noureddine 
Published: April 2011

AbstractThermal energy storage with phase change materials is one of the most efficient ways of storing available energy because of its advantages such as providing higher heat storage capacity, lower storage temperature, isothermal operation and less storage space. This paper reviews the development and investigations of phase change materials in thermal energy storage systems of various engineering applications. There are many phase change materials that melt and solidify at a wide range of temperatures, making them attractive in a lot of applications. Various categories of phase change materials suitable for thermal energy storage are introduced, and the investigations on their important enhancement techniques are also discussed.
High Conducting Heterovalent Substituted NASICON-like Phases in ScPO4-Na3PO4Quasibinary System
Authors: Potapova Anna , Zhuravleva Mariya , Smirnova Irina , Spiridonov Felix , Zimina Galina , Novoselov Andrey 
Published: April 2011

AbstractPhase equilibria in quasibinary system ScPO4-Na3PO4 and formation of heterovalent Zr-substituted solid solutions (up to 10 mol%) for Sc3+ in Na3Sc2(PO4)3 complex phosphate were studied by ceramic technique at 1050°C. Obtained samples were investigated with X-ray powder diffraction and impedance spectroscopy. Zr-substituted (10 mol%) Na3Sc2(PO4)3has ionic conductivity of 3.18.10-1 S/cm at 300°C.
Carbon Nanoparticles for Counter Electrode Catalyst in Dye-Sensitized Solar Cells
Authors: Joshi Prakash , Xie Yu , Mwaura Jeremiah , Ropp Mike , Galipeau David , Qiao Qiquan 
Published: April 2011

AbstractWe report dye-sensitized solar cells using low cost carbon nanoparticles as an alternative to platinum as a counter-electrode catalyst for triiodide reduction. The counter carbon-electrode was deposited onto fluorine-doped tin oxide (FTO) by spin coating from an aqueous colloidal suspension of the blend of carbon nanoparticles and TiO2 nanocrystals. DSSC devices were fabricated using a stable Ru complex dye (Z-907) as the sensitizer. The cells based on carbon-nanoparticle counter electrode were made and then compared with those cells from platinum counter electrode at similar fabrication conditions. The results have shown that the device performance in terms of short circuit current density (Jsc), open circuit voltage (Voc) and energy conversion efficiency (η) from the cells based on carbon nanoparticle counter electrode were comparable to those from platinum counter-electrode devices. The carbon nanoparticle based cells have achieved an overall energy conversion efficiency of 5.55% under one sun AM 1.5 illumination (100 mW/cm2). The carbon nanoparticles showed significant potential as a low cost alternative to the current widely-used platinum.
Phosphorous and Boron Doped Colloidal Silicon Nanocrystals in Conjugated Co-polymers
Authors: Svrcek Vladimir , Fujiwara Hiroyuki , Kondo Michio 
Published: April 2011

AbstractOne-way to improve organic solar cell efficiency is blending conjugated polymer with a second nanocomposite. We report on blending of freestanding boron- and phosphorous-doped environmental friendly silicon nanocrystals (Si-ncs) with two conjugated polymers i.e. (poly(3-hexylthiophene) (P3HT) and poly[methoxy-ethylexyloxy-phenylenevinilene] (MEH PPV)). The electrochemical etching and pulverization of doped porous silicon films are used for fabrication of photesensitive Si-ncs/polymers blends. Processing of Si-ncs dispersed in polymers allows simple tuning of the Si-ncs concentrations in the blends. The blends with high Si-ncs concentrations are prepared and opto-electric properties are compared and discussed. Both types of polymers containing doped Si-ncs showed a photoconductivity response under illumination AM1.5 at ambient temperature and atmosphere.
Thermoelectric High Power Generating Module Made by n-Ba8AlxSi46-x Clathrate
Authors: Munetoh Shinji , Arita Makoto , Makiyama Hideki , Motooka Teruaki 
Published: April 2011

AbstractWe have developed a new thermoelectric power-generating module composed of 72 pieces of n-type Ba8Al18Si28 clathrate elements made by arc melting. The Seebeck coefficient, specific electric resistance and thermal conductivity of Ba8Al18Si28 clathrate were 250 μV/K, 1.9 mΩcm and 3.1 W/mK at 500 °C, respectively, and the thermoelectric figure of merit (ZT) was 0.8. The new thermoelectric module was constructed using only n-type thermoelectric elements connected in series with hook-shaped electrodes. The open-circuit voltage of the module increased with hot-side temperature up to 1.8 V at 500 °C and generated 0.24 W. The module was successfully used to charge lithium-ion batteries for mobile phones.
Actinide Selective Systems for Environmental Extraction and Sensing Applications
Authors: Wu Xianghong , Bharara Mohan Singh , Tate Brandon K , Tonks Stephen A , Vilseck Jonah Z , Gorden Anne Elizabeth Vivian 
Published: April 2011

AbstractThe potential environmental and health concerns surrounding actinides and the use of nuclear fuels limits the acceptance of nuclear power by the public. This in turn, hinders the capability of this country to take advantage of nuclear power. Expanding our fundamental knowledge of actinide coordination chemistry will allow for the development of improved actinide sensors, new separations methods, or new means of radioactive waste remediation. We have designed and optimized a solution-phase parallel method for the synthesis of a library of symmetrical 2-quinoxalinol salens, Schiff-base type ligands with a 2-quinoxalinol incorporated into the salen backbone. This combines the rigid salen coordination framework with the quinoxaline properties that impart properties for use in colorimetric or fluorescent sensors. These have now been incorporated into organic soluble resins for metal extraction.
The Role and Management of Free Water in the Production of Durable Radioactive Waste Products Using Hydraulic Cements
Authors: Angus Michael J. , Butcher Ed , Godfrey Ian H. , Milestone Neil B. 
Published: April 2011

AbstractWater is a necessary component in the production of encapsulated wastes based on hydraulic cements which are widely used for immobilization of intermediate and low level waste (ILW) and (LLW). Apart from providing the fluidity required to readily transport slurry wastes, it plays an essential role in hydrating the cement. Too low a water content prevents homogeneous mixing of the cement binder and waste and does not provide the fluidity needed for effective infilling of solid wastes. The water left after hydration creates a porous network that allows egress of gaseous corrosion/radiolytic degradation products such as hydrogen. A broad envelope (i.e. range) of acceptable water/binder ratios is essential for effective process control, particularly for the encapsulation of slurry wastes which have widely varying water contents.Nevertheless, the presence of large amounts of free water in the pore system of the hardened matrix allows easy transport of soluble ions such as hydroxide, which can lead to metal corrosion, and the increased permeability of the system increases the leachability. Therefore effective management of the ‘free’ water content of a waste product will allow optimisation of both the encapsulation process and the product quality and durability.This paper describes a range of innovative approaches to ‘water management’, including the use of alternative hydraulic cements, modification of powder characteristics and use of superplasticised composite OPC grouts and examines the contribution of 1H NMR relaxometry in providing improved understanding of the distribution of water within the pores of the hardened cement matrix.
High-Efficiency HIT Solar Cells for Excellent Power Generating Properties
Authors: Kinoshita Toshihiro , Ide Daisuke , Tsunomura Yasufumi , Taira Shigeharu , Baba Toshiaki , Yoshimine Yukihiro , Taguchi Mikio , Kanno Hiroshi , Sakata Hitoshi , Maruyama Eiji 
Published: April 2011

AbstractIn order to achieve the widespread use of HIT (Hetero-junction with I etero-Intrinsic T ntrinsic Thin-layer) solar cells, it is important to reduce the power generating cost. There are three main approaches for reducing this cost: raising the conversion efficiency of the HIT cell, using a thinner wafer to reduce the wafer cost, and raising the open circuit voltage to obtain a better temperature coefficient. With the first approach, we have achieved the highest conversion efficiency values of 22.3%, confirmed by AIST, in a HIT solar cell. This cell has an open circuit voltage of 0.725 V, a short circuit current density of 38.9 mA/cm2and a fill factor of 0.791, with a cell size of 100.5 cm2. The second approach is to use thinner Si wafers. The shortage of Si feedstock and the strong requirement of a lower sales price make it necessary for solar cell manufacturers to reduce their production cost. The wafer cost is an especially dominant factor in the production cost. In order to provide low-priced, high-quality solar cells, we are trying to use thinner wafers. We obtained a conversion efficiency of 21.4% (measured by Sanyo) for a HIT solar cell with a thickness of 85μm. Even better, there was absolutely no sagging in our HIT solar cell because of its symmetrical structure. The third approach is to raise the open circuit voltage. We obtained a remarkably higher Voc of 0.739 V with the thinner cell mentioned above because of its low surface recombination velocity. The high Voc results in good temperature properties, which allow it to generate a large amount of electricity at high temperatures.
Dielectric Function and Defect Structure of CdTe Implanted by 350-keV Bi Ions
Authors: Petrik Peter , Fried Miklós , Zolnai Zsolt , Khánh Nguyen Q. , Li Jian , Collins Robert W. , Lohner Tivadar 
Published: April 2011

AbstractIn this work we have developed optical models for the ellipsometric characterization of Bi-implanted CdTe. We have characterized the amount and nature of disorder using Rutherford Backscattering Spectrometry combined with channeling (RBS/C). Samples with a systematically varying degree of disorder were prepared using ion implantation of Bi into single-crystalline CdTe at an energy of 350 keV with increasing doses from 3.75×1013 cm-2 to 6×1014 cm−2. The motivation for use of the high atomic mass Bi ions was that previous studies using lighter ions revealed damage at a low level, even for doses several times higher than the amorphization threshold estimated by simulation [P. Petrik et al., phys. stat. sol. (c) 5, 1358 (2008)]. In contrast, Bi ions create sufficient disorder for investigation of the changes in dielectric function critical point (CP) features in a wider variety of structures from single-crystalline to the disordered state. The CP features can be described by numerous methods starting from the standard CP model, through the parameterization of Adachi [Adachi et al., J. Appl. Phys. 74, 3435 (1993)], and finally to the generalized CP models. The standard CP model has been demonstrated to be a reliable approach for polycrystalline CdTe characterization used in photovoltaic applications [Li et al., phys. stat. sol. (a) 205, 901 (2008)].
MOCVD Growth of High-Hole Concentration (>2×1019 cm−3) P-Type InGaN for Solar Cell Application
Authors: Yu Hongbo , Melton Andrew , Jani Omkar , Jampana Balakrishnam , Wang Shenjie , Gupta Shalini , Buchanan John , Fenwick William , Ferguson Ian 
Published: April 2011

AbstractInGaN alloys are widely researched in diverse optoelectronic applications. This material has also been demonstrated as a photovoltaic material. This paper presents the study to achieve optimum electrically active p-type InGaN epi-layers. Mg doped InGaN films with 20% In composition are grown on GaN templates/sapphire substrates by MOCVD. It is found that the hole concentration of p-type InGaN depends strongly on the Mg flow rate and V/III molar ratio and hole concentration greater than 2×1019 cm−3 has been achieved at room temperature. The optimum activation temperature of Mg-doped InGaN layer has been found to be 550-600°C, which is lower than that of Mg-doped GaN. A solar cell was realized successfully using the InGaN epi-layers presented here.
Properties of P(VDF-TeFE) thin film formed by annealing process with electric field
Authors: Jeong Jong-Hyeon , Kimura Chiharu , Aoki Hidemitsu , Okuyama Masanori , Sugino Takashi 
Published: April 2011

AbstractIn order to apply P(VDF-TeFE) piezoelectric polymer to micro-generator as a membrane, the polymer is deposited on a substrate by spin-coating method. In this process, some changes of properties and quality of the film are caused by a solvent which was used to dissolve the polymer granule. Since a solvent affects the film properties and surface stability, we have carried out the thermal process at a temperature higher than melting point. However, this thermal process due to a temperature higher than Curie point of the polymer causes a falling-off in electrical properties. In this paper, we have studied a method to prevent a falling-off in electric properties of P(VDF-TeFE) film even though the film is annealed at a temperature higher than Curie point.
Informatics for Quantitative Analysis of Atom Probe Tomography Images
Authors: Suram Santosh K , Rajan Krishna 
Published: April 2011

AbstractAn informatics based approach to extract further refinements on the crystallographic information embedded in the Spatial Distribution Maps (SDMs) has been developed. The data mining based methods to generate and interpret spectra that de-convolute the SDMs are discussed. This work has resulted in a method to generate SDMs that can map three-dimensional crystallographic information as opposed to existing methods that map structural information on only one atomic plane at a time. The broader implications of this work on enhancing the interpretation and resolution of structural information in atom probe tomography studies is also discussed.