bluuebunny/crossref_metadata_2025_split huggingface dataset:
Growth of SiOx Nanowires on Self-Assembled Hexagonal Au Particle Networks
Authors: Chiang Tian Fu , Cheng Shao Liang , Chen Lih Juann 
Published: April 2011

AbstractSelf-assembled hexagonal networks with discrete Au particles on Al2O3 (00.1) and Si (111) have been synthesized. SiOx nanowires were grown on individual Au particles using a vapor transport deposition process. The growth of SiOx nanowires was found to cover completely the surface of Au particles on Al2O3 (00.1). On the other hand, the SiOx nanowires were grown selectively on Au particles on Si (111). Interaction of Au and Si substrate is invoked to explain the difference.
Ni Nanoparticles Elaborated with an Ar Ion Polishing Technique
Authors: Torres-Castro Alejandro 
Published: April 2011

AbstractNi nanoparticles where obtained from a Ni sample milled with Ar ions by using a Gatan precision ion polishing system, normally used for Transmission Electron Microscopy (TEM) sample preparation. Deposition of Ni nanoparticles was performed over two different surfaces: on a double sided carbon tape and, on a Cu grid covered with collodion film. A continuos film of Ni was characterized, over the carbon tape by SEM and EDAX techniques. The last surface was analysed by TEM. In both cases, a thin film composed of Ni nanoparticles, was founded and result obtained by TEM, show a nanoparticle diameter of about 4 nm.
Improvement of Electrical Properties of Tin Oxide Nanoparticle by Controlling its Surface Structure
Authors: Hong Sung-Jei , Han Jeong-In 
Published: April 2011

AbstractIn this study, a novel SnO2 nanoparticle was successfully synthesized by controlling its surface structure. The surface structure on the nanoparticle is consistent of Pd and PdO clusters of which size is smaller than 1nm. For uniform dispersion of the clusters, in-situ synthetic method was applied using Sn acetate and Pd acetate. The method enhances uniformity by mixing two elements as an aqueous solution. Also, those materials lower the processing temperature since the removal of organic components is possible below 300°C. HRTEM observation reveals that the size of the synthesized particle is ranged from 2 to 7 nm and the Pd cluster is uniformly distributed in the lattice of SnO2 particle. In fact, XRD analysis certifies the uniform solid solution of the Pd cluster in SnO2 since the localized Pd peak was not found. Specific surface area of the synthesized particle measured with BET surface analyzer exceeded 100 m2/g. Also, the SnO2-5wt%Pd nanoparticle exhibits the excellent change in resistance of 0.62 after aging at 400°C for 5 hours. Also, the electrical properties show very stable phenomena in spite of long- term aging for 400 hours at 400°C. So, the ultrafine SnO2-Pd nanoparticle could be synthesized by using the in-situ synthetic method.
Synthesis and Characterization of Self-Organized Nanostructure Arrays Generated by Laser Irradiation
Authors: Guan Yingfeng , Pedraza A.J. 
Published: April 2011

AbstractOne and two-dimensional arrays of nanoripples and nanoprotrusions can be generated by pulsed laser irradiation. Nanoprotrusions were produced on the surface of silicon when a Lloyd's mirror configuration was used, and could develop to a height of 80 nm. Atomic force and high resolution scanning electron microscopy studies revealed that these structures are preceded by the formation of extended ripples that can reach a height of up to 12 nm. It is shown that one or two identifiable arrays of mutually orthogonal ripples may form. Out of the four differently- spaced ripple arrays that were found, three indicated a very close connection with the production of laser-induced periodic surface structures (LIPSS). Interference of the incoming or refracted laser beam and the laser light scattered by surface undulations has been recognized as the cause of LIPSS formation. The present experiments show that the Lloyd's mirror configuration strongly enhances the formation of ripples and that nanoprotrusions form, sometimes at the intersection of two mutually orthogonal sets of ripples. Each of the beams, the directly incident and the mirror-reflected beam, independently produce an interference pattern with their corresponding scattered beams. However, these two independently generated patterns coincide because their periodicity is only a function of the angle of incidence. Thus, the two interference patterns reinforce each other's effects on the substrate. Single beam, direct irradiation of the substrate failed to induce nanoprotrusions, although 1-D ripple arrays developed.
Line Pattern in Plasma Polymer Films with Embedded Gold and Silver Nanoparticles by Irradiation with Ultrashort Laser Pulses
Authors: Kiesow Andreas , Strohkark Sven , Löschner Katrin , Heilmann Andreas , Podlipensky Alexander , Abdolvand Amin , Seifert Gerhard , Graener Heinrich , Optik Fachgruppe , Physik Fachbereich 
Published: April 2011

AbstractA method to generate line pattern structures in thin organic films with embedded gold and silver nanoparticles is introduced. The films are irradiated with ultrashort, linearly polarized laser pulses. As we find out from electron microscopy (TEM, SEM), periodically arranged line-like structures are formed after the irradiation. We have used so far three different laser wavelengths (266 nm, 400 nm, 800 nm). The resulting structure periods in the range of 170 nm to 600 nm indicate a linear correlation of the period length of the line structures and the wavelength of the incident laser light. The direction of the particle lines corresponds to the linear polarization of the laser pulses. The anisotropic structure modification is mirrored in corresponding anisotropic optical film properties.
Optical Properties of One-Dimensional Metal Nanostructures
Authors: Hao Encai , Zou Shengli , Schatz George C. 
Published: April 2011

AbstractWe present a theoretical study of the optical properties of one-dimensional (1-D) metal nanostructures including nanorods and nanotubes. Although the optical properties of gold nanotubes are similar to that of gold nanorods, both the longitudinal and transverse plasmon resonances of gold nanotubes show much larger red-shifting and narrower. The E-field calculations indicate that the 1-D gold nanostructures, particularly gold nanotubes have great potential for applications to SERS.
Self-Catalytic Branch Growth of SnO2Nanowire Junctions
Authors: Chen Y. X. , Campbell L. J. , Zhou W. L. 
Published: April 2011

AbstractMultiple branched SnO2 nanowire junctions have been synthesized by thermal evaporation of SnO powder. Their nanostructures were studied by transmission electron microscopy and field emission scanning electron microcopy. It was observed that Sn nanoparticles generated from decomposition of the SnO powder acted as self-catalysts to control the SnO2 nanojunction growth. Orthorhombic SnO2 was found as a dominate phase in nanojunction growth instead of rutile structure. The branches and stems of nanojunctions were found to be an epitaxial growth by electron diffraction analysis and high resolution electron microscopy observation. The growth directions of the branched SnO2 nanojunctions were along the orthorhombic [110] and [1 1 0]. The growth of SnO2 nanojunction is controlled by a self-catalytic vapor-liquid-solid growth using Sn nanoparticle catalysts.
ZnO Nanostructures Prepared by Different Methods
Authors: Leung Y. H. , Djurišić A. B. , Choy W. C. H. , Chan W. K. , Cheah K. W. 
Published: April 2011

AbstractZnO is of great interest for photonic applications due to its wide band gap (3.37 eV) and large exciton binding energy (60 meV). Variety of preparation methods and obtained morphologies (such as nanorods, tetrapod nanorods, nanowires, nanoribbons, hierarchical structures, nanobridges, and nanonails) were reported for this material. In this work, the morphology and optical properties of ZnO nanostructures prepared by three different methods were studied. ZnO nanostructures were prepared by oxidation of Zn (no catalyst) at 950°C, heating of a mixture of ZnO:graphite (1:1) at 1100°C, and chemical method (from solution of zinc nitrate hydrate and hexamethylenetetramine at 90°C). The properties of obtained products were examined using scanning electron microscopy, transmission electron microscopy, selected area electron diffraction, X-ray diffraction, room temperature photoluminescence and electron paramagnetic resonance spectroscopy. Chemical synthesis method produced different morphology compared to heating of Zn and ZnO:graphite. In the former case, straight rods are obtained, while in the latter case ZnO tetrapod structures are formed. The ZnO tetrapods, both from Zn and ZnO:graphite, exhibit similar photoluminescence spectra with UV peak and characteristic broad green emission but they have different EPR spectra. The EPR signal g≈1.96 is clearly visible in ZnO tetrapods synthesized from ZnO:graphite, while it is at noise level in ZnO tetrapods synthesized from Zn. Therefore, it can be concluded that the type of intrinsic defects in ZnO nanostructures is strongly dependent on the fabrication conditions, and that the green photoluminescence is not necessarily related to ≈1.96 EPR peak which is commonly assigned to shallow donors.
Magnetic and Electric Manipulation of a Single Cell in Fluid
Authors: Lee Hakho , Hunt Tom P. , Westervelt Robert M. 
Published: April 2011

AbstractMagnetic and electric manipulation of a single cell in a microfluidic channel was demonstrated using a microelectromagnet matrix and a micropost matrix. The microelectromagnet matrix is two perpendicular arrays of straight wires that are separated and topped by insulating layers. The micropost matrix is an array of post-shaped electrodes embedded in an insulting layer. By controlling the current in each wire of the microelectromagnet matrix or the voltage on each electrode of the micropost matrix, versatile magnetic or electric fields were created on micrometer length scales, controlling the motion of individual cells in fluid. Single or multiple yeast cells attached to magnetic beads were trapped and moved by the microelectromagnet matrix; a single yeast cell was directly trapped and moved by the micropost matrix.
Actin Nanotracks for Hybrid Nanodevices Based on Linear Protein Molecular Motors
Authors: Watson G. S. , Cahill C. , Blach J. , Myhra S. , Alexeeva Y. , Ivanova E.P. , Nicolau D. V. 
Published: April 2011

AbstractHybrid nano-devices based on linear protein molecular motors working on micro/nano-engineered surfaces that operate in a “cargo architecture”, i.e. motor functionalized nano-objects running on nano-tracks, offer more opportunities than the inverse “sliding architecture” because it fully uses the information regarding directionality which is encoded in tracks, i.e. actin filaments or microtubules. However, this architecture requires the development of techniques for nanolithography with actin filaments (or microtubules) based on molecular self-assembly on engineered surfaces. The present contribution reports on the progress we have made regarding the building of actin nanostructures that would preserve the inherent information over extended micro-sized areas.
Decoration of Carbon Nanotubes with Gold Nanoparticles for Catalytic Applications
Authors: Lü Wei , Ma Xicheng , Lun Ning , Wen Shulin 
Published: April 2011

AbstractGold nanoparticles supported on carbon nanotubes (CNTs) were prepared by using electroless plating technique. High-resolution transmission electron microscopy (HRTEM) has shown that spherical gold nanoparticles were homogeneously dispersed on the surfaces of the carbon nanotubes with a distribution of particle sizes sharply at around 3-4 nm in diameter. The results presented in this work will probably provide new catalysts with better performances.
Experimental study of filling carbon nanotubes with nucleic acids
Authors: Cui Daxiang , Ozkan Cengiz S. , Kong Yong , Gao Huajian 
Published: April 2011

AbstractEncapsulation of DNA molecules inside carbon nanotubes (CNT) in water were performed under the conditions of 400K and 3Bar. Double stranded DNAs of 2kb and 400bp in length, and single stranded oligonucleotides of 60bp in length were selected as target molecules. Au and Pt nanoparticles and fluorescent dye Cy3 were used as tags. Agarose gel electrophoresis was used to remove DNA molecules attached on the outside walls of CNTs. Laser confocal microscopy, scanning electron microscopy (SEM), high resolution transmission electron microscopy (HR-TEM), energy dispersive x-ray spectroscopy (EDX) were employed to confirm the encapsulation process. The results demonstrated that DNA molecules attached to the outside of CNTs can be removed by electrophoresis. Confocal microscopy and HR-TEM observations as well as EDX analysis confirmed that the Cy3-labelled DNA molecules, Au-labelled oligonucleotides and Pt-labelled DNA fragments can indeed be encapsulated inside CNTs. These experimental results support our earlier molecular dynamics simulations on encapsulating oligonucleotides inside CNTs. The DNA-CNT hybrids could be further explored for potential applications in bio-nanotechnology.
Control of Doping and Electronic Transport in Nanowires
Authors: Zhong Jianxin , Stocks G. Malcolm 
Published: April 2011

AbstractWe propose a novel concept, namely, delta-doping of nanowires, to control the carrier mobility in nanowires. Different from the traditional doping, our approach features doping of a nanowire only on its surface. Our calculations based on Anderson models for nanowires with surface disorder showed remarkably different results from the traditional doping where impurities are distributed inside the nanowire. We found that there exist transition energy levels similar to the mobility edges in three-dimensional disordered systems. If the Fermi energy is below the transition energy level, the delta-doped nanowire is simply an insulator. But once the Fermi energy exceeds this energy level, the carrier mobility increases significantly. The transition levels are almost independent of the degree of disorder in the regime of strong disorder.
Liquid Phase Deposition of Poly(ethylene terephthalate) Films
Authors: Bryce Robert M. , Nguyen Hue T. , Tykwinski Rik R. , DeCorby Ray G. , Freeman Mark R. , Tsui Ying Y. 
Published: April 2011

AbstractPoly(ethylene terephthalate), or PET, has been widely used in experiments due to its excellent properties and availability in sheets as thin as 1.5 µm. Its resistance to chemical attack makes PET a good choice as an inert substrate, but makes liquid phase deposition of thin films from solution challenging. Further, attempts to deposit films from the vapor phase have shown limited success. High quality PET films are desirable, as PET is transparent, hydrophobic, amenable to micropatterning, and is well characterized. As such, PET films are suited for use in microdevices. We report on liquid phase deposition of PET films, and on characterization of the films using optical methods.
Fabrication and Characterization of Platinum-Iridium Electrodes with Micro-Structured Surfaces For Neural Stimulation Applications
Authors: Thanawala Sachin S. , Georgiev Daniel G. , Khan Afzal , Baird Ronald J. , Auner Gregory 
Published: April 2011

AbstractControlled structuring of electrode surfaces on a microscopic scale is expected to decrease the impedance and improve the current injection capabilities of neural stimulation electrodes. We have identified conditions for the fabrication of micro-bumps on platinum-iridium alloy surfaces by means of KrF excimer laser (λ=248nm) irradiation under ambient conditions. A regular array of closely spaced micro-bumps with diameters of about 5µm and heights of about 3µm was generated on the polished face of a platinum-20%iridium wire with a diameter of 75µm. A projection system with a demagnification factor of 9 was used to image a mask with a pattern of circular-holes on the polished face of the wire. Several thousand pulses at a repetition rate of 10Hz and a fluence of 3.0 J/cm2 were applied to produce the micro-bumps. The modified electrode surfaces were studied by optical microscopy and scanning electron microscopy, and the results show the formation of micro-bumps of reproducible shape. Simple two-electrode AC impedance measurements in physiological saline in the frequency range of interest to neural stimulation applications show a considerable decrease in the impedance of micro-structured electrodes with respect to the impedance of a polished electrode.
Electroactive Polymer Deformable Micromirrors (EAPDM) for Biomedical Optics
Authors: Huang Cheng , Bai Bo , Chu Baojun , Ding Jim , Zhang Q.M. 
Published: April 2011

AbstractElectroactive polymers (EAPs) are capable of converting energy in the form of electric charge and voltage to mechanical force and movement and vice versa. Several electroactive polymer actuator materials whose responses are controlled by external electric fields, e.g. poly(vinylidene fluoride-trifluoroethylene) based fluoroterpolymers, have generated considerable interest for use in applications such as artificial muscles, sensors, parasitic energy capture, integrated bio-microelectromechanical systems (BioMEMS) and microfluidic devices due to their high electric-field induced strain, high elastic modulus, high electromechanical coupling and high frequency operation, etc. Scaling the EAP down into microsystems is one of the promising trends of EAP actuators and sensors especially for biomedical engineering. The combination of micro-optics and integrated BioMEMS, referred to as bio-micro-opto-electromechanical systems (BioMOEMS), makes a new opportunity for innovation in the EAP field. We present an approach to the fabrication of low-cost, large-stroke deformable micromirrors based on high performance electroactive polymer film microactuator arrays. Integrated Optic-BioMEMS based on electroactive polymer deformable micromirror (EAPDM) technology provide potential applications in biomedical optics such as ophthalmology (retinal imaging and vision care) and cancer detection and treatment.
Rapid Prototyping of Glass Microfluidic Devices using Femtosecond Laser Pulses
Authors: Park Myung-Il , Choi Jun Rye , Park Mira , Choi Dae Sik , Jeoung Sae Chae , Park Chong-Ook 
Published: April 2011

AbstractLaser micromachining technology with 150 femtosecond pulses is developed to fabricate glass microfluidic devices. A short theoretical analysis of femtosecond laser ablation is reported to characterize the femtosecond laser micromachining. The ablated crater diameter is measured as a function of the number of laser pulses as well as laser fluence. Two different ablation regimes are observed and the transition between the regimes is dependent on both the laser fluence and the number of laser shots. Based on the ablation phenomena described, microfluidic devices are fabricated with commercially available soda lime glasses (76 mm × 26 mm × 1 mm, Knittel Glaser, Germany). In addition to a microchannel for microfluidics, the capillary as well as optical fiber for detecting is integrated on the same substrate. The substrate is successively packaged with a lid slide glass by a thermal direct bonding. The presented developments are suitable for fast turn-around design cycle and inexpensive procedure, which provide rapid prototyping of MEMS devices.
Polariton-enhanced near field lithography and imaging with infrared light
Authors: Shvets Gennady , Urzhumov Yaroslav A. 
Published: April 2011

AbstractA novel approach to making a material with negative index of refraction in the infrared frequency band is described. Materials with negative dielectric permittivity ε are utilized in this approach. Those could be either plasmonic (metals) or polaritonic (semiconductors) in nature. A sub-wavelength plasmonic crystal (SPC), with the period much smaller than the wavelength of light, consisting of nearly-touching metallic cylinders is shown to support waves with negative group velocity. The usage of such waves for sub-wavelength resolution imaging is demonstrated in a numerical double-slit experiment. Another application of the negative-epsilon materials is laser-driven near field nanolithography. Any plasmonic or polaritonic material with nega- tive ε = –εd sandwiched between dielectric layers with εd > 0 can be used to significantly decrease the feature size. It is shown that a thin slab of SiC is capable of focusing the mid- IR radiation of a CO2 laser to several hundred nanometers, thus paving the way for a new nano-lithographic technique: Phonon Enhanced Near Field Lithography in Infrared (PENFIL). Although an essentially near-field effect, this resolution enhancement can be quantified using far-field measurements. Numerical simulations supporting such experiments are presented.
Morphologically Well-defined Gold Nanoparticles Embedded in Thermo-Responsive Hydrogel Matrices
Authors: Wang Chun , Flynn Nolan T. , Langer Robert 
Published: April 2011

AbstractNanocomposite materials consisting of colloidal gold (Au) nanoparticles embedded in thermo-responsive poly(N-isopropylacrylamide) (PNIPAm) hydrogels are synthesized. Thiol groups that bind to both Au3+ ions and colloidal Au are incorporated into the side-chains of the PNIPAm hydrogels through copolymerization. This report describes formation of morphologically well-defined Au nanoparticles with varying long-term stability inside the hydrogel matrices containing adjustable concentrations of thiols. Compared with the non-Au containing PNIPAm hydrogels, the Au-PNIPAm nanocomposite hydrogels have shown higher degrees of equilibrium swelling and different temperature-triggered phase transitions. It is hypothesized that these remarkable changes in hydrogel bulk properties are related to the different morphologies and sizes, and possibly the amount of surface charges, of the Au nanoparticles.
Patterning and Reactive Ion Etching of Diamond Films using Light Coupling Masks
Authors: Leech Patrick W. , Reeves Geoff K. , Holland Anthony S. 
Published: April 2011

AbstractWe describe the novel application of light coupling masks (LCM) in the lithographic patterning of fine structures in diamond films. A PDMS mask was used in the exposure of complex patterns of gratings in AZP 1205 resist on a substrate of Al/ diamond. The profiles of these grating patterns were then modified on a localized scale by a process of reflow of the resist. We report on the transfer of the patterns formed in resist by the LCMs into the diamond film using a sputtered Al layer as a mask. The two-stage process comprised etching of the pattern into the Al followed by transfer into the diamond film using CF4/ O2 and CHF3/ O2 gases. The presence of O2 in the CF4/ O2 and CHF3/ O2 gas mixtures produced Al oxides on the surface of the mask. The etch selectivity of the mask was greater in CF4/ O2 than in CHF3/ O2 gases and was only weakly dependent on the concentration of O2 (0-12 sccm).
Atomic Force Microscopy Applications to Neuroscience
Authors: McNally Helen A. 
Published: April 2011

AbstractIn this research, Atomic Force Microscopy (AFM) is used to investigate living neurons. Three-dimensional images of developing and dying neurons have been obtained, providing neuroscientists their first views of these dynamic structures. The unparalleled resolution provided by AFM reveals dorsal root ganglion (DRG) cells to be more complex and variable than anticipated. AFM is also used to physically contact or manipulate the cell, and thus perturb its development, and/or to measure important physiologically parameters such as surface pressure. Neural cell damage is induced by the AFM tip, which is subsequently used to image the cell's morphological response. A 3-D view of the neural cell collapse, due to this insult, suggests alternative ideas concerning acute neuronal (cellular) sealing and repair. Repair of the injured neuron using electric fields and biomolecules is also investigated, supporting clinical trials for paralysis research. AFM force measurements are used to monitor cellular activity and membrane interactions during various stages of the neural cell life cycle. The full versatility of AFM will be applied to further the understanding of neurogenesis and neurotrauma.