bluuebunny/crossref_metadata_2025_split huggingface dataset:
The two origins of p-type conduction in transparent conducting Ga-doped SnO2 thin films
Authors: Wang Huan-hua , Yang Tieying , Wang Baoyi , Ibrahim Kurash , Jiang Xiaoming 
Published: September 2011

AbstractThe p-type conduction in transparent Ga-doped SnO2 thin films was realized and its two origins were discerned through comparison experiments associated with growth conditions, Rutherford backscattering spectroscopy and x-ray photoelectron spectroscopy analysis. All the experiment results suggest that the adsorbed oxygen both in the grain boundaries and at the surfaces is another origin of the net hole conduction in the polycrystalline thin films. This mechanism provides a fairy well explanation for the growth temperature dependence of the p-type conductivities of the films. It also offers a useful guide to better the properties of p-type conducting oxide thin films.
Identification of Impurity Phases in Cu2ZnSnS4 Thin-film Solar Cell Absorber Material by Soft X-ray Absorption Spectroscopy
Authors: Bär M. , Schubert B.-A. , Wilks R.G. , Marsen B. , Zhang Y. , Blum M. , Krause S. , Yang W. , Unold T. , Weinhardt L. , Heske C. , Schock H.-W. 
Published: September 2011

ABSTRACTThe composition of Cu2ZnSnS4 thin-film solar cell absorbers was varied to induce the.formation of secondary impurity phases. For their identification, the samples have been investigated by Cu L3 and S L2,3 soft x-ray absorption (XAS) spectroscopy. We find that Cu L3 XAS is especially sensitive to the presence of copper sulfides as well as copper oxides and/or changes in the electron configuration, suggesting a basis for future studies of the surface, defect, and interface characterization of similar samples. Additionally, it is shown that the S L2,3 absorption data can be used as a very sensitive probe of the variations in the prevalence of S-Zn bonds in the near-surface region of the investigated samples.
Structure and photocatalytic properties of Bi25FeO40 crystallites derived from the PEG assisted sol-gel methods
Authors: Bu Shundong , Cai Dengrong , Li Jianmin , Yu Shengwen , Jin Dengren , Cheng Jinrong 
Published: September 2011

ABSTRACTSillenite Bi25FeO40 crystallites have been fabricated via a sol-gel approach. X-ray diffraction results show that single-phase Bi25FeO40 can be synthesized at the annealing temperature of 600 oC with the help of PEG additive. The amount of additives and the annealing temperature has great effects on the formation of phase pure Bi25FeO40 crystallites. The morphologies of Bi25FeO40 crystallites were observed by SEM techniques. UV-vis diffuse reflectance spectroscopy indicated the good visible light absorption of Bi25FeO40 crystallites. The photo-catalytic activity of Bi25FeO40 powders was evaluated by the degradation of methyl orange solution assisted by H2O2 under UV-Vis light and Vis-only light irradiation, which suggested that Bi25FeO40 crystallites are potential photocatalytic materials.
New designs of hydrophobic and mesostructured Ultra Low k materials with isolated mesopores
Authors: Grunenwald Anthony , Ayral André , Albouy Pierre Antoine , Rouessac Vincent , Jauffres David , Verdier Marc , Gergaud Patrice , Licitra Christophe , Zenasni Aziz , Jousseaume Vincent , Simon Jean-Paul 
Published: September 2011

ABSTRACTIn this work, hydrophobic mesostructured organosilica thin films, exhibiting isolated mesopores (~ 7 nm), have been successfully deposited by spin-coating using different polystyrene-block-polyethylene oxide copolymers (PS-b-PEO) as structure-directing agents and methyltriethoxysilane (MTES) as organosilica precursor. Different ordered mesostructures (Face Centered Cubic, 2D or 3D Hexagonal and Body Centered Cubic) can be achieved by controlling different synthesis parameters. X-Ray Diffraction (XRD) and Grazing Incidence Small Angle X-Ray Scattering (GISAXS) techniques were used to investigate the mesostructure evolution through thermal and UV treatments. Swelling and shrinkage were evidenced by in-situ XRD and X-Ray Reflectivity measurements during the thermal removal of the meso-templates. Infrared spectroscopy and 29Si NMR were additionally used to investigate the microstructure evolution. The film porosity was estimated thanks to Ellipsometry Porosimetry (EP). Correlation between mechanical properties through nanoindentation measurements and the mesostructure ordering is discussed as well as assessments of the dielectric constant k by mercury contact probe.
Patterning Organic Fluorescent Molecules with SAM Patterns
Authors: Wu Qiong , Hao Juanyuan , Shi Shoulei , Wang Weifeng , Lu Nan 
Published: September 2011

ABSTRACTWe report a low-cost and high-throughput method to fabricate large-area light emitting pattern via thermal evaporation of organic molecules on the patterned self-assembled monolayer of homogenous 3-aminopropyltrimethoxysilane. This method is based on the selective deposition of the organic light emitting molecules on the template of self-assembled monolayer (SAM), which is patterned with nanoimprinting lithography. The selectivity can be controlled by adjusting the design of the pattern, the storage duration and the substrate temperature. The deposition selectivity of the molecules may be caused by the different binding energy of the molecules with the SAM and the substrate surface.
Microstructure of sputter-deposited noble metal-incorporated oxide thin films patterned by means of laser interference
Authors: Catrin Rodolphe , Gries Thomas , Horwat David , Migot Sylvie , Muecklich Frank 
Published: September 2011

ABSTRACTLaser interference patterning-induced microstructural modifications have been investigated in two noble metal-incorporated oxide thin film systems: Pd0.25Pt0.75Ox and gold-incorporated yttria-stabilized zirconia - Au-YSZ. Transmission electron microscopy was used to investigate the influence of the laser treatment on the microstructure of the samples. In the case of Pd0.25Pt0.75Ox, the formation of a nanocomposite arrangement resulted from the precipitation of metal nanograins in the oxide matrix triggered by laser irradiation. In Au-YSZ, the starting microstructure consisted of gold nanograins embedded in a YSZ matrix. A noticeable growth and coalescence of gold nanograins occurred near the surface in the region of maximum interference. Simultaneously, a foamy morphology, mostly consisting of gold crystals, was formed at the film surface. In contrast to thermal annealing, the laser treatment proposed here is a fast procedure to partially relocate gold at the film surface and provide a local solid lubrication.
Experimental Demonstration of Hopfield Neural Network using DNA molecules
Authors: Akin Hayri E. , Karabay Dundar , Mills Allen P. , Ozkan Cengiz S. , Ozkan Mihrimah 
Published: September 2011

ABSTRACTDNA Computing is a rapidly-developing interdisciplinary area which could benefit from more experimental results to solve problems with the current biological tools. In this study, we have integrated microelectronics and molecular biology techniques for showing the feasibility of Hopfield Neural Network using DNA molecules. Adleman’s seminal paper in 1994 showed that DNA strands using specific molecular reactions can be used to solve the Hamiltonian Path Problem. This accomplishment opened the way for possibilities of massively parallel processing power, remarkable energy efficiency and compact data storage ability with DNA. However, in various studies, small departures from the ideal selectivity of DNA hybridization lead to significant undesired pairings of strands and that leads to difficulties in schemes for implementing large Boolean functions using DNA. Therefore, these error prone reactions in the Boolean architecture of the first DNA computers will benefit from fault tolerance or error correction methods and these methods would be essential for large scale applications. In this study, we demonstrate the operation of six dimensional Hopfield associative memory storing various memories as an archetype fault tolerant neural network implemented using DNA molecular reactions. The response of the network suggests that the protocols could be scaled to a network of significantly larger dimensions. In addition the results are read on a Silicon CMOS platform exploiting the semiconductor processing knowledge for fast and accurate hybridization rates.
Improvement of solubility and biocompatibility of MnO based nanoparticles in aqueous solutions
Authors: Koll Kerstin , Schladt Thomas D. , Weber Stefan , Jochum Florian D. , Theato Patrick , Schreiber Laura M. , Tremel Wolfgang 
Published: September 2011

ABSTRACTMnO nanoparticles were surface modified using two different multifunctional polymers. By introducing a PEG group, the long term stability, MRI applicability and sterile filtration could be greatly improved. Furthermore, PEGylated MnO NPs were less toxic compared to non-PEGylated NPs. The results suggest that these nanoparticles are suitable for in vivo applications.
Rational Designs on TiO2-based Nanocomposites for Solar Photocatalytic Purification
Authors: Gao Shanmin , Xu Tao 
Published: September 2011

ABSTRACTWe report an template-free process to fabricate S-C-codoped and (I2)n-C-codoped meso/nanoporous TiO2 nanocrystallites. Methylene blue solutions are used as a model pollute to evaluate the sorption and photocatalytic activity of the samples under visible light radiation. The high photocatalytic activity in visible light region of our samples is attributed to numerous oxygen vacancies, large specific surface area and the continuous states in the band gap of TiO2 introduced by I2 or S doping.
Anodically Fabricated Sr-doped TiO2 Nanotube Arrays for Photoelectrochemical Water Splitting Applications
Authors: Hamedani Hoda A. , Allam Nageh K. , Garmestani Hamid , El-Sayed Mostafa A. 
Published: September 2011

ABSTRACTThe present work reports the synthesis of self-organized strontium-doped titania nanotubes arrays as a potential material for photocatalytic water splitting. Electrochemical anodization process was used to grow such material under various electrochemical conditions. The effect of dopant concentration on the morphology and photoelectrochemical properties of the material was investigated. The microstructure, morphology and composition of as-prepared and heat treated nanotubes were characterized by field emission scanning electron microscopy (FESEM), x-ray diffraction (XRD), transmission electron microscopy (TEM) and x-ray photoelectron spectroscopy (XPS). The results showed that increasing the dopant concentration up to its solubility limit results in higher photoelectrochemical activity. A preliminary proof of concept of the photocatalytic activity of the fabricated material was estimated in terms of the use of such material as a photoanode for photoelectrochemical water splitting.
Morphology and Electronic Structures of Calcium Phosphate Coated Titanium Dioxide Nanotubes
Authors: Liu Lijia , Kim Sun , Chan Jeffrey , Sham Tsun-Kong 
Published: September 2011

ABSTRACTTitanium dioxide nanotubes (TiO2-NT) have been synthesized via an electrochemical anodization strategy followed by calcination under different temperatures to form TiO2 nanostructures of anatase and rutile crystal phases. The nanotube-on-Ti structure is further used as a substrate for calcium hydroxyapatite (HAp) coating. The effect of TiO2 morphology and crystal phases (i.e. amorphous, anatase and rutile) on the coating efficiency of HAp has been investigated in comparison with HAp coating on bare Ti metal. The HAp coated TiO2-NT have been studied using X-ray absorption near-edge structure (XANES) at the Ti K- and Ca K-edge. The results show that TiO2 of amorphous and anatase phases are of comparably good performance for HAp crystallization, and both are better than rutile TiO2, while HAp is hardly found on bare Ti. The implications of the findings are discussed.
Microcapsule-based materials for electrophoretic displays
Authors: Dai Runying , Wu Gang , Yin Peipei , Chen Hongzheng 
Published: September 2011

ABSTRACTElectrophoretic displays, the rewritable non-light-emitting display technology based on the movement of colored pigments inside a low dielectric liquid as a voltage is applied, have attracted a great deal of academic and commercial interests due to the combination of the advantages of both electronic displays and conventional paper, including paper-like high contrast appearance, ultra-low power consumption, thinness, flexibility etc. Fabrication of electrophoretic ink by microencapsulating the electrophoretic suspension into individual microcapsules is one way to realize such application. However, there are still some limitations for its commercial application, such as the dispersion and the electrophoretic mobility of charged particles due to the nano-particles aggregation, the barrier property and stability of microcapsule wall due to the suspension releasing, etc. In this presentation, systematic studies on the preparation of electrophoretic particles and microencapsulation by complex coacervation method were carried out to solve the mentioned problems. The obtained microcapsules can be quasi-monolayer coated on ITO/PET substrate and driven by static mode to obtain a matrix character display prototype.
Hybrid Aerogel-MLI Insulation System Performance Studies for Cryogenic Storage in Space Applications
Authors: Begag R. , White S. , Fesmire J.E. , Johnson W.L. 
Published: September 2011

ABSTRACTLong duration storage of large quantities of cryogenic fluids for propulsion, power, and life-support is an essential requirement for missions into space. Efficient and reliable insulation materials are key to the success of these missions. The required insulation material must outperform the current standard multi-layer insulation (MLI) for thermal insulation and provide additional features such as durability, micrometeoroid orbital debris protection, and flexibility, all in one single-layer material. Ultra-low density and highly hydrophobic fiber reinforced aerogel material integrated with MLI has the potential to offer a great insulation package which will overcome several issues that the current standard MLI alone suffers from such as: 1) damage during installation, 2) high cost, and 3) degradation over time. The hybrid aerogel/MLI solution affords a more reliable alternative because it is robust, and will outperform the MLI in cases of vacuum loss. Low density and highly resilient methylsilicate aerogel will contribute less solid conductivity to the overall heat transfer within the aerogel/MLI system. Sol-gel optimization of low density and low dust methylsilicate aerogels will be presented. Thermal performance of two prototypes of hybrid aerogel/MLI composites and a baseline MLI system (1 inch thick, 90 layers) fabricated by Aerospace Fabrication and Materials (AFM) and tested at cryogenic temperatures under different vacuum level conditions (at Cryogenic Laboratory, NASA KSC) will also be presented.
Design and Functionalization of Magnetic Core-Shell Oxide Nanoparticles Exhibiting Exchange Bias Features
Authors: Mammeri Fayna , Mamèche Faïza , Kataya Zeinab , Yaacoub Nader , Slawska-Waniewska Anna , Menguy Nicolas , Grenèche Jean-Marc , Ammar Souad 
Published: September 2011

ABSTRACTCore-shell magnetic nanoparticles (CSNPs) composed of a ferrimagnetic core (CoFe2O4) embedded in an antiferromagnetic shell (CoO) were produced using seed mediated growth in a polyol. Different core sizes and shell thicknesses were considered. The structural and magnetic properties of assemblies of these nanoparticles were characterized by means of X-ray Diffraction, Transmission Electron Microscopy, dc-magnetometry (SQUID) and 57Fe Mössbauer spectrometry. The measured EB magnetic field values, at low temperature, are found to be weak whatever the microstructural characteristics of the studied CSMNPs. Simultaneously, both the magnetization and the interparticle interaction (mainly dipolar) appear clearly reduced when the shell thickness increases.
Effects of direct lateral Current Injection on the Performance, Overall Efficiency and Emission Distribution in GaN LED structures: a 2D Computational Study
Authors: Kivisaari Pyry , Oksanen Jani , Tulkki Jukka 
Published: September 2011

ABSTRACTWe study and demonstrate the potential benefits of using a transverse junction structure in GaN LEDs by simulating and comparing the structure with conventional vertical injection structures.The direct current injection component enabled by the transverse structure significantly reduces the height of the polarization-induced potential barriers and facilitates the electron flow into the active material, improving the overall efficiency. In addition, the transverse junction structure enables a more even radiative recombination distribution from different quantum wells. We estimate the attainable optical output efficiency and also discuss the influence of the active layer design on the quantum efficiency. Based on the obtained results, shifting from the conventional 1-dimensional LED structures to genuinely 2-dimensional structures may allow new possibilities to optimize LED performance.
Electromechanical Response of Multilayered Polymer Films for High Energy Density Capacitors
Authors: Wolak Mason A. , Shirk James S. , Mackey Matt , Carr Joel , Hiltner Ann , Baer Eric 
Published: September 2011

ABSTRACTMultilayered films comprising alternating layers of polycarbonate (PC) and poly(vinylidene fluoride-hexafluoropropylene) (P[VDF-HFP]) show an enhanced dielectric strength (EB> 750 kV/mm) and an increased energy storage density (Ud ~ 13.5 J/cm3) compared to monolithic PC and P[VDF-HFP] films. Here the role of electromechanical effects in the breakdown of multilayer films is explored both by imaging the changes in the layer structure caused by electrical fields below the breakdown field and by a direct measurement of the strain in multilayer PC/ P[VDF-HFP] films subjected to similar fields. Focused Ion Beam (FIB)/ Scanning Electron Microscopy (SEM) images of the layer structure in films subjected to repeated cycles at near-breakdown fields showed local changes in the thickness of individual layers, suggesting that mechanical forces arising from field-induced compression may play a role in the steps preceding the breakdown. The directly measured field induced strain showed evidence for both an elastic and a flow component to the strain. The mechanical responses of films with ≤ 50 vol% P[VDF-HFP] were modeled as simply the sum of an elastic and viscous flow. The observed electromechanical properties vary with the layer structure. This suggests that multilayering polymers may provide a means to mitigate deleterious electromechanical effects in low modulus, high dielectric materials.
The Study about the Control of Defect Factors to Improve Properties of P(VDF-TeFE) Thin Film
Authors: Jeong Jong-Hyeon , Terashima Daiki , Kimura Chiharu , Aoki Hidemitsu 
Published: September 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. Since a solvent affects the film properties and surface stability, we have carried out the thermal process at a temperature higher than melting point. In the annealing process of a P(VDF-TeFE) thin film, electrical properties of the film was improved by an application of an electric field. The established study was the investigation of variations in characteristics by an application of a certain electric field. We have attempted to measure about the critical intensity of an electric field and investigate what the influences of the application is caused using a XPS spectrum in this study. Moreover, in order to control the intrusion of impurities, we have used the vacuum chamber to carry out the annealing process in it.
Characterization and Optimization of Fluid Flow in a High Biot Number System
Authors: Wlezien Richard , Prapas Jason , Briggs Sarah , Hodes Marc , Manno Vincent , Matson Douglas , Chiesa Luisa 
Published: September 2011

ABSTRACTExperiments and analysis have been conducted to characterize flow separators used in applications where heated fluid passes between layers of solid material such as in the manufacturing of gelatinous materials. The Biot number of the configuration is the key parameter, and must be taken into account when optimizing performance. It is shown that most prior work was for low Biot number systems, and the particular configurations under consideration operate at high Biot number. Existing designs developed for lower Biot number (such as membrane filter spacers) are shown to perform poorly for this application. An experimental apparatus was designed and fabricated to quantitatively assess pressure drop through the system using different separation strategies. These results were compared with a simplified two-term model based on the physics of viscous drag in these devices. Channels without separators behave like classical Poiseuille flow. Channels with separators can be modeled with a two-term equation: a baseline Poiseuille term and a form drag term. A variety of separator designs are compared and their overall performance is discussed. We also illustrate the high sensitivity to gap height in all configurations.
A Hexagonal Pillar Array of Thermo-responsive Soft Actuators Prepared by Nanoimprinting
Authors: Wu Ching-Mao , Lin Szu-Yin , Huang Kuo-Tung 
Published: September 2011

ABSTRACTThermo-responsive actuation (thermomechanical effects) based on nematic liquid crystal elastomers (LCEs) have become a research priority in the preparation of soft actuators. Nematic LCEs combine the anisotropic features of liquid crystal phases with the rubber elasticity of polymer network. When heated at nematic to isotropic phase transition temperature (N-to-I temp.), a uniaxial thermomechanical deformation of LCEs will undergo at nearly constant volume due to a change of LC director order. Recently, an array of the micro-sized LCE pillars related to such thermomechanical effects have been successfully constructed through a soft lithography technology (i.e., replica molding). The prepared LCE pillars are mono-dispersive and micro-sized. They also possess N-to-I temp. higher than 100°C, largely limiting the available application. By contrast, the present study will report a hexagonal array of nano-sized thermo-responsive pillar actuators that are able to contract and expand in response to temperature changes around a lower N-to-I temp. is manufactured via using reactive rod-like liquid crystal and ultraviolet nanoimprinting technology. According to atomic force microscope (AFM) observation, a hexagonal array of pillars can be easily constructed by nanoimprinting and a responsive surface with a thermo-stimuli-driven roughness change is achieved. The room-temperature AFM scans quantitatively represent the single pillar shows a diameter of ca. 270 nm and 140 nm in depth, and the pitch meaning the averaged inter-pillar distance is measured as ca. 425 nm, thus lying in a nano-sized range. Furthermore, temperature-variable AFM is also utilized to demonstrate the pillar behaves as a thermally-stimulated nano-sized actuator. In our case, when heated above N-to-I phase transition temperature (ca. 65°C), it is clearly observed that the pillar diameter is expanded in the order of over 12-15 % and then reversibly contracted in response to temperature drop.