bluuebunny/crossref_metadata_2025_split huggingface dataset:
TEM Investigation of Epitaxial Assembly in Aggregates of BaTiO3 and CaTiO3 Nanocrystalline Particles Synthesized under Hydrothermal Conditions
Authors: Iwaji Naoki , Takebe Hiromichi , Kuwabara Makoto 
Published: April 2011

ABSTRACTWe investigated epitaxial assembly in aggregates of BaTiO3 and CaTiO3 nanocrystals, which were synthesized under a hydrothermal condition at 150°C using distilled water-ethanol solvent, by transmission electron microscopy analysis. The volume ratio of distilled water-ethanol used as the solvent gives a significant influence on the crystal growth of the nanocrystals. The obtained results indicate that epitaxial assembly is surely involved in the crystal growth of BaTiO3 and CaTiO3 nanocrystals under the present thermal condition.
Enhancement of light transmission through nanoslit in a circular metallic film flanked by parallel periodic gratings
Authors: Kumar Dinesh , Asakawa Kiyoshi 
Published: April 2011

ABSTRACTWe investigate the potential of a slit grating structure on a silver film embedded in a high index dielectric film, as a Plasmonic optical antenna in infrared region. Using FDTD calculations it is demonstrated that the transmission properties of the structure has strong dependence on the dimension of dielectric film. By tapering the height of output gratings directionality of the emitted beam has been improved. We propose the application of the Plasmonic antenna and examine its performance in axial injection of light from single mode fiber to photonic crystal waveguide.
Atomic Structure of PtRu Nanoparticle Catalysts and Their Methanol Oxidation Activity
Authors: Nitani Hiroaki , Honda Yusuke , Horioka Ryo , Ohara Kosuke , Kawaguchi Takuya , Nakagawa Takashi , Seino Satoshi , Yamamoto Takao A. , Daimon Hideo 
Published: April 2011

ABSTRACTPtRu bimetallic nanoparticles supported on carbon nanoparticle (PtRu/C) catalysts were synthesized with radiation irradiation. The samples were structural analyzed by techniques of X-ray absorption fine structure (XAFS), transmission electron microscope (TEM) and X-ray diffraction (XRD). The results indicated that PtRu/C catalysts which prepared by an electron beam irradiation had more homogeneous atomic arrangement than that prepared by a gamma-ray irradiation. We found a clear correlation between the atomic structure and the catalytic activity of PtRu/C catalysts. These results supported the bi-functional mechanism.
Preparation and Photocatalytic Properties of TiO2/SiO2Composite Nanofibers
Authors: Lee Sung Wook , Lim Tae Ho , Kim Sang Beom , Hyun Dong Ho 
Published: April 2011

ABSTRACT(1-x)SiO2/(x)TiO2composite micro/nano scale fibers with various compositions were successfully prepared by electrospinning their sol-gel precursors of titanium(IV) isopropoxide(TiP), and tetraethyl orthosilicate(TEOS), followed by calcinations. Any gelator or binder was not used in this direct preparation process for composite fibers. The surface morphology and structure of sintered composite fibers were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), and Fourier transform infrared (FT-IR). The crystallization behavior and surface morphology of the as-spun fibers were largely influenced by the calcination temperature and the content of TiO2. The photocatalytic activity of SiO2/TiO2composite fibers was examined by UV-DRS spectra. The experiments demonstrated that the MB in aqueous solution was successfully photodegraded using SiO2/TiO2composite nanofibers under UV-visible light irradiation.
Flame Retardant Intumescent Polyamide 11-Carbon Nanofiber Nanocomposites: Thermal and Flammability Properties
Authors: Lao Si Chon , Koo Joseph H , Morgan Alexander , Jor Hung-Kai , Nguyen Khiet , Wissler Gerhardt , Pilato Louis , Luo Zhiping 
Published: April 2011

ABSTRACTCurrent polyamide 11 and 12 are lacking in fire retardancy and high strength/high heat resistance characteristics for fabricated parts that are required for performance driven applications. The introduction of selected nanoparticles such as carbon nanofibers (CNFs), combined with a conventional intumescent flame retardant (FR) additive into the polyamide 11/polyamide 12 (PA11/PA12) by melt processing conditions has resulted in a family of intumescent polyamide nanocomposites. These intumescent PA11 and PA12 nanocomposites exhibit enhanced polymer performance characteristics, i.e., fire retardancy, high strength, and high heat resistance and are expected to expand the market opportunities for resin manufacturers. The overall objective of this research is to develop improved PA11 and PA12 polymers with enhanced flame retardancy, thermal, and mechanical properties for selective laser sintering (SLS) rapid manufacturing. Arkema RILSAN® PA11 polymer was examined with CNFs and Clairant Exolit® OP 1230 intumescent FR additive. They were used to create a family of FR intumescent PA11-CNF nanocomposites. Transmission electron microscopy (TEM) was used to determine the degree of CNFs and intumescent FR additive dispersion in PA11. Injection molded specimens were fabricated for material properties measurements. Thermal stability of these polymer nanocomposites (PNs) was examined by TGA. Flammability and thermal properties of these PNs were obtained using the cone calorimeter, UL 94 test method, and heat deflection temperature.
Functionalized Photonic Crystal Sensor Elements based on Nanoporous Polymers
Authors: Kim Sung Jin , Nio Elizabeth , Chodavarapu Vamsy P , Titus Albert H , Swihart Mark T , Cartwright Alexander N 
Published: April 2011

ABSTRACTWe report the development of oxygen sensors using polymer photonic bandgap structure and CMOS chips. These integrated sensors provide a new platform for the development of low cost, low (battery) powered, light weight, robust, fast and small sensors. We demonstrate an approach to encapsulation of chemical and biological recognition elements within the porous structures. This sensing platform is built on our recently demonstrated nanofabrication technique using holographic interferometry of a photo-activated mixture that includes a volatile solvent as well as monomers, photoinitiators, and co-initiators. Resulting structure is nanoporous polymer 1D photonic bandgap structures that has reflection grating property and can be directly integrated into optical sensor systems that we have previously developed. For optical sensor system, CMOS (Complementary Metal Oxide Semiconductor) detectors that include phototransistors, trans impedance amplifier, and other signal processing units are used. Combining CMOS chip and nano-porous polymer reflection grating, we demonstrate an oxygen sensor as a prototype by encapsulating the fluorophore (tris(4,7-diphenyl-1,10-phenathroline)ruthenium(II) using fluorescence intensity.
Optical Properties of Double-Decker-Shaped Poly (Silsesquioxane)
Authors: Watanabe Akira , Tadenuma Shohei , Miyashita Tokuji 
Published: April 2011

ABSTRACTThe double-decker-shaped silsesquioxane (DDSQ) is a new family of silsesquioxanes consisting of a Si-O-Si case structure and functional organic side chains. The optical properties of a novel organic-inorganic hybrid polymer based on the DDSQ were studied. The double-decker-shaped poly(silsesquioxane) (DDPSQ) showed excellent transparency and thermal stability. The thermo-optic coefficient of the DDPSQ is 3 or 4 times larger than conventional polymers.
Structure and Luminescence of Ce-doped Lu2SiO5 Nanophosphor
Authors: Blair Michael Wayne , Jacobsohn Luiz G , Bennett Bryan L , Muenchausen Ross E , Sitarz Stephanie C , Smith James F , Cooke D Wayne , Crozier Peter A , Wang Ruigang 
Published: April 2011

ABSTRACTNanophosphors correspond to nanostructured inorganic insulator materials that emit light under particle or electromagnetic radiation excitation. In this work we investigate the structure and luminescent properties of Ce-doped Lu2SiO5 (LSO) nanophosphors prepared by solution combustion synthesis with the Ce content 0.1 to 12 at. %. Samples were characterized by transmission electron microscopy (TEM), line scan electron energy-loss spectroscopy (EELS), x-ray diffraction (XRD), and electron paramagnetic resonance (EPR) spectroscopy. Photoluminescence excitation and emission spectra are composed of two major bands centered at 360 and 430 nm, respectively. These results reveal a red-shift and enhanced Stokes shift for the nanophosphors when compared to bulk. Ce content was also found to affect photoluminescence emission intensity and fluorescent lifetime. The nanophosphor concentration quenching curve presents a broad maximum centered at 1 at.%. Lifetime measurements show a continuous decrease from 34 to 21 ns as Ce content is increased.
Investigation of Nano-thin β-SiC Layers for Chemical Sensors
Authors: Rahimi Ronak , Raghavan Srikanth , Shelton N.P. , Penigalapati Dinesh , Balling Andrew , Woodworth Andrew A. , Denig Tobias , Stinespring Charter D. , Korakakis D. 
Published: April 2011

ABSTRACTSilicon Carbide possesses a combination of properties that make it ideal for use in electronics. Its high values of electric breakdown field, melting point and saturated electron drift velocity have attracted the attention of the semiconductor community. Although the interest in β-SiC/Si devices has intensified in recent years [1-2], little focus has been given to the study of nano-thin film devices. Monocrystalline nano-thin β-SiC films have been reproducibly grown on Si (100) by Gas Source Molecular Beam Epitaxy (GSMBE). Auger Electron Spectroscopy and Reflection High Energy Electron Diffraction characterization have confirmed a growth consistent of β-SiC/Si. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) characterization has determined film thicknesses of 30nm. These nano-films have been used in the fabrication of Metal-Semiconductor-Metal (MSM) devices formed from aluminum Schottky contacts. Under electrical characterization, these MSM devices have exhibited unique properties in that the dominant conduction path does not occur at the β-SiC/Si interface [3] as previously reported, but within the entire β-SiC layer. It is proposed that the device is isolated from the Silicon substrate and due to the nano-thin β-SiC films used in this work the differentiation between surface and ‘bulk’ is not clear. Results obtained through chemical experimentation have indicated that conduction is largely dependent on the surface condition of the device. This suggests the possibility for nano-thin, surface-like, β-SiC films to be used in chemical agent sensors.
In-situ synthesis of Si3N4/TiN nanocomposite powders in cryogenic solution
Authors: Yang Mei , Lü Mingli , Zhu Hongmin 
Published: April 2011

ABSTRACTA new method of Si3N4/TiN nanocomposite powders through reaction at low temperatures was proposed and tested. The reduction of titanium chloride and silicon chloride by sodium was conducted in liquid ammonia at the temperature range of −40°C∼−50°C, and titanium nitride and silicon nitride nanopowders were obtained. Based on these reactions, in-situ coating and co-precipitation were conducted. The TiN nano-particles deposited on the surface of Si3N4 particles as the nuclei in the in-situ coating and in the co-precipitation two or more source of ions were reduced uniformly in the liquid ammonia. Si3N4/TiN nanocomposite powders were prepared by the both routes and were characterized with X-ray diffraction, transmission electron microscopy. The effects of in-situ and the particle size on the morphology of the composite were discussed.
Dielectric and Thermomechanical Properties of Polypropylene/Multi-Walled Carbon Nanotubes Nanocomposites
Authors: Kanapitsas A. , Logakis E. , Pandis C. , Zuburtikudis I. , Pissis P. , Delides C. G , Vatalis A. S. 
Published: April 2011

ABSTRACTThe purpose of this work is to examine the dielectric, electrical and thermo-mechanical properties of multi-walled carbon nanotubes (MWCNT) filled polypropylene nanocomposites formed by melt-mixing. To that aim dielectric relaxation spectroscopy (DRS) and dymamic mechanical analysis (DTMA) were employed. The results are discussed in terms of nucleating action of MWCNT and interfacial polymer-filler interactions. Special attention is paid to percolation aspects by both ac conductivity measurements for the samples which are above the percolation threshold and permittivity measurements for the samples which are below percolation threshold.
Phase Separation in Silica Sol-gel System Containing Anionic Surfactant
Authors: Matsui Taisuke , Nakanishi Kazuki , Kanamori Kazuyoshi , Hanada Teiichi 
Published: April 2011

ABSTRACTBy inducing phase separation parallel to the sol-gel transition of alkoxy-derived silica systems, silica monoliths with well-defined co-continuous macropores were obtained from the systems containing anionic surfactants. We adopted three kinds of anionic surfactants which differ from each other in the length of alkyl chain (CH3(CH2)17SO3Na, CH3(CH2)15SO3Na, CH3(CH2)13SO3Na). Mesopores were also found in the silica skeletons presumably by the supramolecular templating. Characterization of the dried or heat-treated samples was carried out by a scanning electron microscope (SEM) and nitrogen adsorption measurements. Experimental results showed that due to the moderate interaction between silica oligomers and surfactants, most of the surfactants are distributed to the solvent phase which determines the macropore volume. The median size and volume of the macropores could be controlled independently by the starting composition. In the absence of any additive to enhance templating by the surfactant, the samples exhibited only amorphous mesopores.
Examination of Mesopore Structure of Hierarchically Macro/mesoporous Silica by Thermoporometry
Authors: Fukui Etsuji , Shinohara Keiske , Nakanishi Kazuki , Kanamori Kazuyoshi , Hanada Teiichi 
Published: April 2011

ABSTRACTThermoporometry was employed to monitor the mesopore evolution in wet, drying and heat-treatment stages of monolithic macro/mesoporous silica with SBA-15 like structure. Direct comparison of mesopores in wet state was only possible with the samples extracted with sulfuric acid. In good agreement with the preceding study, the sulfuric acid not only removed the surfactant but also modified the silica gel network into that with reduced amount of micropores and increased stability against the drying stress. Thermoporometry revealed that the structural evolution takes place completely in the wet condition, which accompanies a decrease in the thickness of non-freezable water.
Chemical Data Writing into Metal/oxide Interface: Characterization of Low Dimensional Interface Reactions by I-V Measurements
Authors: Ishii Masashi , Nakao Aiko , Sakurai Kenji 
Published: April 2011

ABSTRACTWe investigated electric and chemical properties of metal/Y2O3 interfaces. The Pt/Y2O3 interface can be chemically activated by bias voltage, resulting in a microscopic oxidation-reduction center at interface. The oxidation-reduction of the center alternatively changed resistance of the Pt/Y2O3 system, and the alternation yield hysteresis with respect to the bias voltage, i.e. a memory effect. On the other hand, in Au/Y2O3 system, non-oxidization of Au induced ejection of O2 gas from the interface, so that there was no memory effect. Possible reactions of these metal/Y2O3 systems were proposed, and the balance between oxidation and reduction at microscopic center was concluded to be essential for the memory effect.
Engineered Nanocomposites for Solid Oxide Fuel Cells By Colloidal Crystal Templating
Authors: McLachlan Martyn A , Ying An , Kilner John A , McComb David W , Skinner Stephen J 
Published: April 2011

ABSTRACTColloidal crystal templating has been used to prepare three-dimensionally ordered macroporous (3DOM) films of La1-xSrxMnO3-d (LSM), yttria stabilized zirconia (YSZ) and porous composites of LSM and YSZ. These materials have direct applications as cathodes in solid oxide fuel cells (SOFCs). The 3DOM materials have been prepared by low temperature processing, which is a major step towards overcoming electrode sintering, interdiffusion and deleterious phase formation associated with conventional high temperature processing. The preparation of porous composites and the elimination of high temperature densification presents an opportunity to create SOFCs with a large number of triple phase boundaries which should be accompanied by an corresponding improvement in device performance. The microstructure of the 3DOM films was assessed using scanning electron microscopy and the crystal structure and phase purity assessed by x-ray diffraction.
Failure and Formation of Axial Nanowire Heterostructures in Vapor-Liquid-Solid Growth
Authors: Paladugu Mohanchand , Zou Jin , Guo Ya-Nan , Auchterlonie Graeme J. , Joyce Hannah J. , Gao Qiang , Tan H. Hoe , Jagadish Chennupati , Kim Yong 
Published: April 2011

ABSTRACTTo observe the axial growth behavior of InAs on GaAs nanowires, InAs was grown for different growth durations on GaAs nanowires using Au nanoparticles. Through transmission electron microscopy, we have observed the following evolution steps for the InAs growth. (1) In the initial stages of the InAs growth, InAs cluster into a wedge shape preferentially at an edge of the Au/GaAs interface by minimizing Au/InAs interfacial area; (2) with further growth of InAs, the Au particles move sidewards and then downwards by preserving an interface with GaAs nanowire sidewalls. The lower interfacial energy of Au/GaAs than that of Au/InAs is attributed to be the reason for such Au movement. This downward movement of Au nanoparticle later terminates when the nanoparticle encounters InAs growing radially on the GaAs nanowire sidewalls, and with further supply of In and As vapor reactants, the Au nanoparticles assist the formation of InAs branches. These observations give some insights of vapor-liquid-solid growth and the kinks formation in nanowire heterostructures.
Engineering Morphology of Surfaces by Oblique Angle Etching
Authors: Cansizoglu Mehmet F. , Karabacak Tansel 
Published: April 2011

ABSTRACTDuring a typical chemical etching process growth front morphology generally generates an isotropic rough surface. In this work, we show that it is possible to form a rippled surface morphology through a geometrical self-assembly process using a chemical oblique angle etching technique. We observe in our Monte Carlo simulations that obliquely incident reactive species preferentially etch the hills that are exposed to the beam direction due to the shadowing effect. In addition, species with non-unity sticking (etching) coefficients can be re-emitted from the side walls of the hills and etch the valleys, which at the end can lead to the formation of ripples along the direction of the beam. This mechanism is quite different than the previously reported ripple formation during ion-beam bombarded surfaces where the particles have much higher energies, lower incidence angle and ripple formation is mainly due to physical deformation of the surface. We investigate the ripple formation process in our simulated surfaces for a wide range of etching angle and sticking coefficient values.
Strain-assisted Formation of Nano-scaled Lamellar Structure in Ti-39at%Al Single Crystals
Authors: Koizumi Yuchiro , Tanaka Takayuki , Takeshi Fujita , Yoritoshi Minamino 
Published: April 2011

ABSTRACTWe have studied the effects of straining prior to annealing for lamellar structure formation in a Ti-39at%Al single crystal intending to accelerate the lamellar structure formation and decrease the resultant lamellar spacing via preferential nucleation of γ-TiAl phase at dislocations in α2-Ti3Al phase. In a crystal cold-rolled to 10% reduction before annealing, a fine lamellar structure with 88 nm average spacing was formed by annealing at 1073 K for 1×104 s whereas no lamella were observed in the crystal subjected to the same annealing without cold-rolling. In addition, it was also demonstrated that when the crystal is locally strained by indentation and annealed at 1073 K for 1×104 s, a lamellar structure with 43 nm average lamellar spacing is formed in areas near the indentation and there were no lamella beyond these areas. This means that distributions of lamellae can be controlled by controlling the distribution of strain before annealing.
Development of Oil/Water/Surfactant Microemulsions as Templates for Micro and Nanostructured Metal Foams
Authors: Cock Catherine , Renee Woo , O'Neil Brenda , Leigh McKenzie , Manning Jason , Bakker Martin Gerard 
Published: April 2011

ABSTRACTThere are a range of applications for bicontinuous metal micro and nanostructures including as porous electrodes for supercapacitors, in fuel cells and in advanced batteries. We have previously demonstrated a number of methods of generating metal nanostructures by electrodeposition into various templates including hexagonal surfactant phases and mesoporous silica. More recently we have been exploring the application of oil-in-water microemulsions as templates. We have found empirically that the formation of microstructure is strongly effected by the viscosity of the oil phase, the rate of metal electroreduction and the surface roughness of the substrate. We interpret these observations as reflecting a competition between growth of the metal around the oil droplet and the redistribution of the oil in front of the growing metal film. We are currently exploring bicontinuous and water-in-oil phases with the expectation that such templates will yield bicontinuous metal films with larger accessible surface areas. Preliminary results with water-in-oil phases appear to show the formation of bicontinuous nanostructured films on the 20 nm length scale.
Modified Microparticles of Calcium Alginate Gel for Controlled Release of Anesthetics
Authors: Batyrbekov Erkesh E. , Akylbekova Turar N. , Iskakov Rinat M. 
Published: April 2011

ABSTRACTThe aim of this work is the development of controlled delivery system immobilized by local anesthetics on the basis of modified microparticles of calcium alginate gels. The kazkain, rikhlokain, lidokain and novokain were used as local anesthetics. Modified microparticles were obtained by syringed dropwise a solution of ansthetics in sodium alginate into solution of polymers such as chitosan or polyethyleneimine in calcium chloride. The obtained modified alginate microparticles were contained immobilized anesthetics in core of particles and a surface layer of polymer. Effects of polymer concentration and exposure duration on the thickness of polymer coating were determined. The release of anesthetics from the modified alginate gel particles into a physiological solution with different thickness of coating were studied. All the release data show the typical pattern for a matrix controlled mechanism. The cumulative amount of drug released from alginate gels was linearly related to the square root of the time and the release rate decreased this time. The process is controlled by the diffusion of anesthetics through the polymeric coating. The data shown a possibility of the regulation of the rate of anesthetics release from the modified alginate particles by way of alternation of thickness of the polymer coating. The anesthetic effect of the alginate microparticles containing drugs was tested on rats by method “tail flick” according two criteria: full analgesia – the absence of reaction on pain and sufficient analgesia – exceeding of pain threshold sensibility two and more times. Medical-biological tests show that the duration of anesthetic activity for the drug-containing alginate beads increases at 5-8 times in comparison of free drugs.