bluuebunny/crossref_metadata_2025_split huggingface dataset:
Carbon Layer as a New Material for Optics
Authors: Clergereaux R. , Escaich D. , Martin S. , Raynaud P. , Gaillard F. 
Published: April 2011

AbstractPlasma enhanced CVD produces carbon layers with various properties which are highly correlated to the different process parameters such as monomer structure, plasma type or plasma power. For example, the modification of monomer (CH4 to C4H10) or the plasma source and the increase of plasma power lead to an optical band-gap which runs from 0.9 to 4.3eV, a conductivity from 5·103 to 5·105S.m−1 and a refractive index from 1.47 to 2.76. Then, it is able to control the optical and electrical film properties from the external process parameters. This paper will thus be focused on the description of relation between deposition parameters, structural characteristics of material and film properties. These materials can then be used for optoelectronics applications.
The characteristics of joints with Indium-silver alloy using diffusion soldering method
Authors: Kim Je Yoon , Park Sang Won , Yoon Jee Young , Kim Hwa Young , Lee Dae Yeon , Kim Gyu Tae , Sung Man Young , Kang Ey Goo 
Published: April 2011

AbstractBonding process using indium-silver alloy which can withstand high temperature was investigated at relatively low temperature. We used a thermal evaporator and vacuum coater for making indium-silver contact. From the result of experiment, we observed that indium and silver films which have good quality are formed. From phase diagram of In-Ag alloy, we can find that melting point of these compounds increases with the silver content, i.e. eutectic (144° C) <AgIn2 (166° C) < (300° C) < (670° C) < (695° C). And these compounds are determined by the composition ratio of the source metal. Now we confirmed the thermal characteristics of Indium-Silver alloy is controlled by silver. Consequently we have developed Ag/In/Ag multi-layer composite which has higher melting point than that of normal contact. The melting point of Ag/In/Ag multi-layer is about 700° C. The joint cross-sections are studied using SEM(scanning electron microscopy) and EDX(Energy Dispersive X-rays). From these data, we observed that the composition and microstructure of Ag/In/Ag multi-layer were reliable and this bonding procedure is a better technique compared to the conventional structure of quantum well LED and GaN/Si LED structure was made by using sapphire for substrate and might be good for high temperature electronic devices in the future.
White-Light Emitting Diode through Ultraviolet InGaN-pumped Sr2Si1−xGexO4 : Eu2+ phosphors
Authors: Kim J.S. , Jeon P.E. , Kim W.N. , Choi J.C. , Park H.L. , Kim G.C. 
Published: April 2011

AbstractThe Sr2Si1−xGexO4 : Eu2+ phosphors are formed by means of a new synthesis method. The Sr2Si1−xGexO4 : Eu2+ have the mean particle size of 200 nm and the spherical shape. The Sr2Si1−xGexO4 : Eu2+ show two emission colors : the blue color of 480 nm and the green color of 525 nm. The intensity of green band with respect to blue band is significantly decreased in comparison with that of solid-reacted bulk sample, described by the hindrance of the energy transfer between the blue and green band by numerous nanoparticle boundaries. As the increase of Ge4+ ions, the 480 nm emission intensity of the Sr2Si1−xGexO4 : Eu2+ are more dominant. This behavior can be understood in terms of the effect of Ge4+ ions on the energy transfer from 480 nm band to 525 nm band. The fabricated white-light emitting diode using ultraviolet InGaN chip with the blue and green emitting Sr2Si1−xGexO4 : Eu2+ phosphor shows warm white light of 4300 K and higher color stability against input power in comparison with a commercial blue GaN-pumped YAG:Ce3+.
Structure of Cobalt Nanosphere Superlattice Films by Small Angle X-ray Scattering
Authors: Beerman Michael , Ohnuma Masato , Bao Yuping , Krishnan Kannan M. 
Published: April 2011

AbstractCobalt nanocrystals, recently synthesized with narrow size distributions and controlled shapes, organize in a wide range of arrays as a function of shape, size and interparticle interactions. The nanocrystals (NCs) consist of a cobalt metal core with a nominal diameter of 11 nm, and an organic surfactant surface layer with a chain length of ∼1.7 nm. For the simplest case (ε-Co nanospheres, super-paramagnetic at room temperature) a hexagonal arrangement of NCs is observed in transmission electron microscope (TEM) images when precipitated from solution onto carbon films. For practical applications and for further understanding of the self-assembly process, long range order of the super lattice must be probed over regions that are greater in extent than may be examined by TEM. Hence, small angle x-ray scattering (SAXS) measurements were performed on cobalt nanospheres randomly dispersed in solution and assembled on glass substrates. Least squares fit to the intensity distribution as a function of the scattering vector q gave an average particle diameter of 11.0 ± 0.8 nm. Structure factor contribution to the intensity profile agrees well with a quasi-random model for scattering from a face centered cubic (FCC) superlattice composed of uniform radius cobalt spheres. The measured nearest neighbor interparticle spacing, 14.1 nm, agrees to within 2% of the predicted value of 14.4 nm based on a free energy model that governs the self-assembly of the nanoparticle system.
Transmission Electron Microscopy (TEM) Studies of Ge Nanocrystals
Authors: Xu Q. , Sharp I.D. , Liao C.Y. , Yi D. O. , Ager J.W. , Beeman J.W. , Liliental-Weber Z. , Yu K.M. , Zakharov D. , Chrzan D. C. , Haller E.E. 
Published: April 2011

Abstract74Ge nanocrystals were formed by ion beam synthesis in SiO2. Transmission Electron Microscopy was used to characterize the structure and properties of these Ge nanocrystals before and after liberation from the matrix. The liberation from the SiO2matrix was achieved through selective etching in a HF bath. High-resolution micrographs and selective area diffraction confirm that the crystallinity is retained in this process. Transfer of released nanocrystals is achieved through ultrasonic dispersion in methanol and deposition onto lacey carbon films via evaporation of methanol. In an effort to determine the melting point of Ge nanocrystals and observe the growth and evolution of nanocrystals embedded in the amorphous SiO2during heat treatment, as-grown nanocrystals were heatedin-situup to 1192°C±60°C in a JEOL 200CX analytical electron microscope. Electron diffraction patterns are recorded using a Charge-Coupled Device. A large melting hysteresis was observed around the melting temperature of bulk Ge.
Image-Based Nanocrystallography in Future Aberration-Corrected Transmission Electron Microscopes
Authors: Moeck P. , Qin W. , Fraundorf P. B. 
Published: April 2011

AbstractSince the crystallographic phase and morphology of many materials changes with the crystal size in the one to hundred nanometer range and the potential technological applications of nanoparticles are enormous, a need arises to determine the crystallography of nanoparticles individually. Direct space high- resolution phase-contrast transmission electron microscopy (TEM) and atomic resolution Z-contrast scanning TEM when combined with goniometry of direct and/or reciprocal lattice vectors offer the possibility of developing dedicated nanocrystallography characterization methods for such small nanoparticles. Although experimentally feasible for cubic nanocrystals with lattice constants larger than 0.4 nm in contemporary high-resolution TEMs with modest tilt range, image-based nanocrystallography by means of transmission electron goniometry has so far only been employed by a few specialists worldwide. This is likely to change in the future with the availability of aberration-corrected TEMs. The reasons why this change is likely to happen are outlined in this paper.
Fabrication of CdTe Quantum Dot Arrays on GaAs utilizng Nanoporous Alumina Masks
Authors: Jung Mi , Lee Hong Seok , Park Hong Lee , Mho Sun-Il 
Published: April 2011

AbstractThe uniformity and reproducibility of the CdTe QD arrays on the GaAs substrates can be improved by using a nanoporous mask. The CdTe QDs on the GaAs substrate were grown by a molecular beam epitaxy (MBE) method. The nanoporous alumina masks used for the fabrication of QD arrays have the thickness from 0.3 νm to 5 νm with the nanochannels of ∼ 80 nm diameter and the pore density of ∼ 1010cm−2. When the thickness of the alumina mask used for the CdTe QD growth was about 300 nm, the CdTe QD arrays formed as a replica of the nanochannels of the mask. Smaller self-assembled CdTe QDs located randomly were produced by using the thicker nanochannel mask than 0.5 νm. The thickness of the nanochannel mask controls the size of the CdTe/GaAs QDs.
Formation of an Ordered Array of Nanocrystalline Si Dots by Using a Solution Droplet Evaporation Method
Authors: Tsuchiya Yoshishige , Iwasa Tatsuya , Tanaka Atsushi , Usami Ko-Ichi , Mizuta Hiroshi , Oda Shunri 
Published: April 2011

AbstractThis paper reports on a new bottom-up technique of forming silicon nanostructures based on natural aggregation of nanocrystalline (nc) -Si dots in the solution. We first study how the nc-Si dots deposited on the Si substrate get mobile in the solution by simply dipping the substrate with the nc-Si dots on into various solutions. We then demonstrate a solution droplet evaporation method that utilizes aggregation of the dots when we evaporate a solution droplet applied onto the nc-Si dots randomly deposited on the Si substrate. It is shown that the nc-Si dots are assembled well in a droplet of the hydrofluoric acid solution, resulting in various regular patterns on the substrate.
Photochromic Nanofiber Aggregates of PVA/H3PMo12O40 Hybrid
Authors: Gong Jian , Gao Fengmei , Pan Yan , Cui Xiujun , Qu Lunyu , Wang Rongshun 
Published: April 2011

AbstractPoly (vinyl alcohol) (PVA)/H3PMo12O40ultra-fine fiber aggregates contained differential weight percentage of H3PMo12O40 to PVA (20, 50 and 80 wt.%, respectively) have been successfully prepared by electrospinning technique. By means of IR spectrum, wide-angle X-ray diffraction, and scanning electron microscope (SEM) techniques, the fiber aggregates were characterized. The result from scanning electron microscopy (SEM) showed that the average diameter of the fibers was between 240-900 nm. The photochromic behavior of the fiber aggregates was investigated by means of IR, UV-Vis spectra and electron spin resonance (ESR). The results showed that the Mo atom of H3PMo12O40 was reduced via one-electron step and the PVA was oxidized to unsaturated ketone after the PVA/H3PMo12O40 fiber aggregates was irradiated under UV light. The color of the fiber aggregates changed from white to blue under ultraviolet irradiation and the photochromism of the fiber aggregates was reversible in air condition.
Nucleation and Growth of Gold Nanoparticles Deposited by RF-Sputtering: An Experimental Study
Authors: Barreca Davide , Gasparotto Alberto , Pierangelo Elisabetta , Tondello Eugenio 
Published: April 2011

AbstractGold nanoparticles were deposited on SiO2, Si(100) and HOPG (Highly Oriented Pyrolitic Graphite) by RF-sputtering from Ar plasmas. Sample preparation was performed at temperatures as low as 60°C under different total pressures, RF-powers and deposition times, with particular attention to the influence of process parameters and growth surface on nanosystem properties. In this paper, the most important results regarding the compositional, structural and morphological features of the obtained specimens, are presented and discussed.
Nanolithographic Manipulated Cutting of Aligned Metal Oxide Nanowires
Authors: Campbell L.J. , Chen Y.X. , Zhou W.L. 
Published: April 2011

AbstractControlling the characteristics of nanowires in order to later construct nanoarchitecture and nanocomponents for nanodevice and nanosensor applications is essential. Metal oxide nanowires are aligned using the Langmuir-Blodgett (LB) technique to uniaxially compress the nanowires. A surfactant monolayer of metal oxide nanowires is fabricated, and then compressed on an aqueous subphase. The compression yields an array of aligned nanowires, which is transferred to a planar substrate. Cutting areas of the array are defined by electron beam nanolithography. After an etching process, it is shown that the metal oxide nanowires have been successfully cut. With further refinement of this technique, the nanowires can be used to construct basic building blocks of nanodevices and nanosensors.
Synthesis of Indium Tin Oxide Nanoparticles and Application to Near IR-reflective Film
Authors: Song Ja Eun , Kang Young Soo 
Published: April 2011

AbstractITO nanoparticles were synthesized by coprecipitation method in an aqueous solution and thermal method in an alcohol solution. The coprecipitate prepared at room temperature showed the crystal structure of indium oxide in X-ray diffraction when it was annealed above 300°C. In thermal method, the nanoparticles have two phase crystal structure of indium oxide hydroxide (InOOH) and indium hydroxide (In(OH)3). Annealing at the temperature above 300 °C, it showed the rhombohedral crystal structure of indium oxide (In2O3). The phase transition of ITO nanoparticle was also detected with DSC. Near IR-reflective film was prepared by spin coating using ITO sol solution. Transmission electron microsopy (TEM) and energy dispersive X-ray spectrometer (EDS) were used to characterize the morphology and composition of ITO nanoparticles. Near-IR (NIR) spectrometer was used to determine reflectance on the surface of ITO film in the NIR-radiation region.
Photoluminescent Enhancement of Ruthenium Complex Monolayers by Surface Plasmon Resonance of Silver Nanoparticles
Authors: Pan Shanlin , Wang Zhenjia , Rothberg Lewis J. 
Published: April 2011

AbstractThe photoluminescence intensity from a bis (2,2'-bipyridine)-(5-isothiocyanato-phenanthroline) Ruthenium (RuBICP) monolayer covalently bound to a glass substrate is found to be enhanced up to 20 times when silver nanoparticles are deposited on top. The emission spectra are blue shifted by interactions with the silver nanoparticles. Field enhancement is found to be able to enhance the radiative decay rate by over three orders of magnitude but fewer than 2 % of the molecules in the sample experience this large enhancement. Increased absorption rates also increase the luminescence but to a much smaller degree.
Effect of Template Materials on the Top Morphologies of Cu Nanowires
Authors: Lin Ran-Jin , Wu Luh-Huei , Tsai Ching-Hsiang , Sung Chien-Min 
Published: April 2011

AbstractAn array of copper nanowires (50-110 nm in diameters) was deposited by the electrolysis of CuSO4-H2SO4 solution at room temperature using DC current. The array was created by forcing deposited copper to follow a pattern of nano tunnels. These nano tunnels were formed with two different methods: anodizing an aluminum film that coated on a silicon wafer to form nano holes within oxidized alumina, and etching the ion-tracked polycarbonate membrane.The difference in top morphologies of the Cu nanowires in these templates is very marked. The copper nano wires deposited in anodized alumina template form the separate spherical balls with diameter of about 10 νμ on the surface of the alumina film, in spite of the template thickness of only 0.5 νm. In contrast, no such Cu agglomeration was formed with copper nano wires deposited in holes of polycarbonate. This variance in copper morphologies is likely due to the difference of the interface energy between Cu and anodic alumina and that of Cu and polycarbonate.
Synthesis and Characterization of Novel Au(core)-Au/Pt Alloy(shell) Nanostructure
Authors: Liu Ru-Shi , Chen Hau-Ming , Hu Shu-Fen 
Published: April 2011

AbstractA systematic study is reported about the amount-dependent morphology change in a series of Au-Pt bimetallic nanoparticles synthesized using chemical reduction. The amount of Au precursor is kept constant throughout whole series of compounds to obtain fixed Au core size (∼7.5 nm). The Au/Pt ratio is varied from 1/1 to 1/4 in order to synthesize Pt shell layer of different thickness. We observed a remarkable shift of surface plasmon band around 410 nm. With the aid of high resolution transmission electron microscope (HRTEM) and energy-dispersive spectrometer (EDS), the composition of shell layer is found to be Pt enriched Au-Pt alloy. As the amount of Pt increases, the Pt clusters formed a string-like shape on the surface of nanoparticles. The average diameter of these Pt clusters is about 2 nm. This special structure may exhibit unique catalytic property.
Covalent Coupling of Gold Nanoparticles to Multiwalled Carbon Nanotubes for Electronic Device Applications
Authors: Ma Xicheng , Lun Ning , Li Xia , Wen Shulin 
Published: April 2011

AbstractCreating hybrid nanostructures of disparate nanoscale blocks is of interest of exploring new types of electronic devices and networks. Here, we demonstrate the novel coupling of gold nanoparticles of 3-4 nm diameters to sidewall of multiwalled carbon nanotubes (MWNTs) using the electroless plating technique. MWNTs were initially chemically modified with an H2SO4-HNO3 acid treatment, and subsequently activated with Pd-Sn catalytic nuclei via a one-step activation approach. When the activated MWNTs were immersed in a gold-containing electroless plating bath, gold deposition occurred at the catalytic sites. The deposited gold clusters then catalyze further gold deposition on the tube surface (autocatalytic process). Novel hybrid nanostructures with gold nanoparticles homogeneously distributed on MWNTs resulted. High-resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray spectroscopy (EDS) were used to characterize the conjugation process.
Spherical Aberration Corrected Z-STEM Characterization of CdSe and CdSe/ZnS Nanocrystals
Authors: McBride James , Kippeny Tadd C. , Pennycook Stephen J. , Rosenthal Sandra J. 
Published: April 2011

AbstractSpherical aberration corrected Atomic Number Contrast Scanning Electron Microscopy (Z-STEM) has recently demonstrated an amazing ability to not only obtain sub-angstrom levels of detail but also yield chemical information at that level as well. With an optimal probe size of 0.8 Å, extremely detailed images of CdSe nanocrystals were obtained showing the lattice structure and surface morphology. As an example of the usefulness of this technique, a sample of CdSe nanocrystals prepared using trioctylphosphine oxide (TOPO) as the surfactant was compared to a sample of CdSe prepared using a mixture of TOPO and hexadecylamine (HDA) as the surfactant. The TOPO/HDA nanocrystals exhibit a narrower size distribution and several orders of magnitude greater fluorescence compared to that of the TOPO only nanocrystals. Interestingly, the Z-STEM images show a striking difference in nanocrystal morphology as the result of the addition of HDA to the reaction mixture. This result suggests surface morphology can be tuned through judicious choice of surfactant. A second example of Z- STEM imaging involves the characterization of CdSe/ZnS core/shell nanocrystals. The mass contrast afforded by Z-STEM can easily distinguish between core and shell.
Reaction and diffusion dynamics in a microfluidic format
Authors: Kohlheyer Dietrich , Lammertink Rob G. H. , Schlautmann Stefan , Besselink Geert A. J. , Vulto Paul , Schasfoort Richard B. M. 
Published: April 2011

AbstractA novel microfluidic structure based on the electroosmotic guiding of reagent streams is presented that can be used as a fully adjustable diffusion based microreactor. The position and the width of two aqueous reactant streams entering a laminar-flow chamber can be controlled individually by changing the flow ratio of three parallel guiding streams containing buffer only. To control the intensity of product formation, the overlapping area between the diffusion regions of the two different reagent streams can be adjusted. This article describes the fabrication and experimental characterization of the device.
Design and Fabrication of a Constant Shear Microfluidic Network for Tissue Engineering
Authors: Weinberg E.J. , Borenstein J.T. , Kaazempur-Mofrad M.R. , Orrick B. , Vacanti J.P. 
Published: April 2011

AbstractRecent progress in microfabrication of biodegradable materials has resulted in the development of a three-dimensional construct suitable for use as a scaffold for engineering blood vessel networks. These networks are designed to replicate the critical fluid dynamic properties of physiological systems such as the microcirculation within a vital organ. Ultimately, these 3D microvascular constructs will serve as a framework for population with organ-specific cells for applications in organ assist and organ replacement. This approach for tissue engineering utilizes highly engineered designs and microfabrication technology to assemble cells in three-dimensional constructs which have physiological values for properties such as mechanical strength, oxygen, nutrient and waste transport, and fluidic parameters such as flow volume and pressure.Three-dimensional networks with appropriate values for blood flow velocity, pressure drop and hematocrit distribution have been designed and fabricated using replica molding techniques, and populated with endothelial cells for long-term microfluidic cell culture. One critical aspect of the fluid dynamics of these systems is the shear stress exerted by blood flow at the walls of the vessel; a key parameter because of well-known mechanotransduction phenomena from mechanical shear forces which govern endothelial cell behavior. In this work, we report the design and construction of three-dimensional microfluidic constructs for tissue engineering which have uniform wall shear stress throughout the network. This type of control over the shear stress offers several advantages over earlier approaches, including more uniform seeding, more rapid achievement of confluent coatings, and better control over endothelial cell behavior for in vitro and in vivo studies.
Synthesis and Characterization of Ag Nanoparticle, Ag-TiO2 Nanoparticle and Ag-TiO2-Chitosan Complex and Their Application to Antibiosis and Deodorization
Authors: Kim Young Hwan , Kang Young Soo 
Published: April 2011

AbstractAg nanoparticles have been prepared by thermal decomposition of Ag-oleate complex using electric furnace at 300 °C for about 4 hrs. TEM images of the particles showed 2-dimensional assembly of particles with diameter of 8.0 ± 1.3 nm, demonstrating the uniformity of these nanoparticles. Ag-TiO2 nanoparticles were synthesized by sol-gel process and they had core-shell structure. Results showed the formation of the silver core and titanium oxide shell. In this study, we investigated the structure of Ag nanoparticle and Ag-TiO2 nanoparticle and Ag-TiO2-chitosan complex and their functions of antibiosis and deodorization.
Integrating Biomaterials into Microsystems: Formation and Characterization of Nanostructured Titania
Authors: Samah Zuruzi Abu , Butler Blaine C. , Parker Emily R. , Ahmed Ayesha , Evans Heather M. , Safinya Cyrus R. , MacDonald Noel C. 
Published: April 2011

AbstractWe demonstrate the facile fabrication of crack-free nanostructured crystalline titania into microsystems. Titania layers were formed by reacting Ti thin films, deposited by evaporation and sputtering, with aqueous H202. Cracks were observed in titania layers formed on blanket Ti films but absent on arrays of patterned Ti pads below a threshold dimension. Nanostructured titania formed from sputtered and evaporated Ti films consists of aligned fibrous and sponge-like nanoporous morphologies, respectively. Rat fibroblasts L-cells cultured on these titania fibers remain viable up to 3 days. These observations demonstrate the feasibility of this technique to integrate nanostructured titania into Nano|Micro-Electromechanical systems (N|MEMS) devices.