bluuebunny/crossref_metadata_2025_split huggingface dataset:
Atomic Ordering in Nano-layered FePt: Multiscale Monte Carlo Simulation
Authors: Kozubski Rafal , Kozlowski Miroslaw , Wrobel Jan , Wejrzanowski Tomasz , Kurzydlowski Krzysztof J , Goyhenex Christine , Pierron-Bohnes Veronique , Rennhofer Marcus , Malinov Savko 
Published: March 2010

AbstractCombined nano- and mesoscale simulation of chemical ordering kinetics in nano-layered L10 AB binary system was performed. In the nano- (atomistic) scale Monte Carlo (MC) technique with vacancy mechanism of atomic migration was implemented with diverse system models. The mesoscale microstructure evolution was, in turn, modeled by means of MC procedure simulating antiphase boundary (APB) motion as controlled by APB energies evaluated within the nano-scale simulations. The study addressed FePt thin layers considered as a material for ultra-high density magnetic storage media and revealed metastability of the L10 c-variant superstructure with monoatomic planes parallel to the (001) free surface and off-plane easy magnetization. The layers, initially perfectly ordered in the L10 c-variant, showed homogenous disordering running in parallel with a spontaneous re-orientation of the monoatomic planes into a mosaic-microstructure composed of L10 a- and b-variant domains with (100)- and (010)-type monoatomic planes, respectively. The domains nucleated heterogeneously on the Fe free surface of the layer, grew discontinuously inwards its volume and finally relaxed generating an equilibrium microstructure of the system. Two �atomistic-scale� processes: (i) homogenous disordering and (ii) nucleation of the L10 a- and b-variant domains showed characteristic time scales. The same was observed for the meso-scale processes: (i) heterogeneous L10 variant domain growth and (ii) domain microstructure relaxation. The above phenomena modelled within the present study by means of multiscale MC simulations have recently been observed experimentally in epitaxially deposited thin films of FePt.
An Interactive Desktop Computer Program for Simulating Nanometer Scale Surface Pattern Formation
Authors: Wang Michael 
Published: March 2010

AbstractNanometer-scale patterns may form as one or more chemical components deposit on a solid substrate. This self-assembly process can be described by a set of nonlinear integral-differential diffusion equations accounting for two opposing factors: phase separation to minimizing Gibb's free energy in individual surface phases and reduction in phase boundaries to minimize surface energy created by phase separation. I here present a desktop computer program that allows us to interactively simulate self-assembly of nanometer-scale surface patterns. In particular, this program provides a convenient tool for studying the effects of temperature variations and preexisting patterns on the self-assembly process. Computer simulations show that an increase in temperature may enlarge pattern sizes and can eventually lead to the disappearance of the patterns.
Molecular dynamics simulation of ds-DNA on a gold surface at low surface coverage
Authors: Lee One-Sun , Schatz George C. 
Published: March 2010

AbstractMolecular dynamics methods have been used to study the conformation of ds-DNA on a gold surface for low surface coverage at the atomistic level. Each ds-DNA strand, which is attached to the [111] surface of gold with a -S(CH2)6- linker, is found to be nearly perpendicular to the surface and maintaining the Watson-Crick B-DNA conformation. The tilt angle between the ds-DNA and an axis normal to the gold surface is 7.3 (+/-) 2.2 degree. The concentration of counterions around the ds-DNA is increased by a factor of 1.8 relative to the bulk, which is significantly lower than in our previous simulations of ds-DNA at high surface coverage.
Density-Functional Analysis on Vacancy Orbital and its Elastic Response of Silicon
Authors: Ogawa Takafumi , Tsuruta Kenji , Iyetomi Hiroshi , Kaneta Hiroshi Yamada , Goto Terutaka 
Published: March 2010

AbstractRecent experiments on ultrasonic measurements of non-doped and boron-doped silicon indicate that vacancies in crystalline silicon can be detected through the elastic softening at low temperature. This is attributed to enhanced response of electronic quadrupole localized at the vacancies to the elastic strain. In the present work, the electronic quadrupole moment of the vacancy orbital in silicon and their strain susceptibility are evaluated quantitatively by using the density-functional method. We show the orbital of gap state is localized around vacancy but extended over several neighbors. The effect of applied magnetic field on the vacancy orbital and its multipole structures are also investigated. We find that the results obtained from these calculations are consistent with the ultrasonic experiments.
InGaAs/GaAsSb Heterostructures: Aluminum-Free Intersubband Devices
Authors: Nobile Michele , Strasser Gottfried , Detz Hermann , Mujagic Elvis , Andrews Aaron , Klang Pavel , Schrenk Werner 
Published: March 2010

AbstractAn experimental study on mid-infrared intersubband absorption in InGaAs/GaAsSb multiple quantum wells grown lattice-matched to InP substrates by molecular beam epitaxy is presented. Intersubband absorption in a broad wavelength region (5.8 - 11.6 μm) is observed in multiple quantum well samples with well widths ranging between 4.5 and 12 nm. A conduction band offset at the InGaAs/GaAsSb heterointerface of 360 meV gives an excellent agreement between the theoretically calculated ISB transition energies and the Fourier-transform infrared spectroscopy measurements over the whole range of well widths under investigation. Two kinds of intersubband devices based on the InGaAs/GaAsSb material system are presented: a quantum well infrared photodetector operating at a wavelength of 5.6μm and an aluminum-free quantum cascade laser. The presented quantum cascade laser emits at a wavelength of 11.3 μm, with a threshold current density of 1.7 kA/cm2 at 78 K.
MESFETs on H-terminated Single Crystal Diamond
Authors: Calvani Paolo , Rossi Maria Cristina , Conte Gennaro , Carta Stefano , Giovine Ennio , Pasciuto Benedetto , Limiti Ernesto , Cappelluti Federica , Ralchenko Victor , Bolshakov A. , Sharonov G. 
Published: March 2010

AbstractEpitaxial diamond films were deposited on polished single crystal Ib type HPHT diamond plates of (100) orientation by microwave CVD. The epilayers were used for the fabrication of surface channel MESFET structures having sub-micrometer gate length in the range 200-800 nm. Realized devices show maximum drain current and trasconductance values of about 190 mA/mm and 80 mS/mm, respectively, for MESFETs having 200 nm gate length. RF performance evaluation gave cut off frequency of about 14 GHz and maximum oscillation frequency of more than 26 GHz for the same device geometry.
RF Power Performance Evaluation of Surface Channel Diamond MESFET
Authors: Rossi Maria Cristina , Calvani Paolo , Conte Gennaro , Camarchia Vittorio , Cappelluti Federica , Ghione Giovanni , Pasciuto Benedetto , Limiti Ernesto , Dominijanni Donatella , Giovine Ennio 
Published: March 2010

AbstractLarge-signal radiofrequency performances of surface channel diamond MESFET fabricated on hydrogenated polycrystalline diamond are investigated. The adopted device structure is a typical coplanar two-finger gate layout, characterized in DC by an accumulation-like behavior with threshold voltage Vt ∼ 0-0.5 V and maximum DC drain current of 120 mA/mm. The best radiofrequency performances (in terms of fT and fmax) were obtained close to the threshold voltage. Realized devices are analyzed in standard class A operation, at an operating frequency of 2 GHz. The MESFET devices show a linear power gain of 8 dB and approximately 0.2 Wmm RF output power with 22% power added efficiency. An output power density of about 0.8 W/mm can be then extrapolated at 1 GHz, showing the potential of surface channel MESFET technology on polycrystalline diamond for microwave power devices.
Nanodiamonds Particles as Additives in Lubricants
Authors: Michail Ivanov G. , S Pavlyshko V. , Ivanov D. M. , Petrov Igor , McGuire Gary , Shenderova Olga 
Published: March 2010

AbstractIn the current work we report results of tribological testing of stable colloidal dispersions of detonation nanodiamond (DND) and polytetrafluoroethylene (PTFE) in mineral oil based greases as well as in polyalphaolefin (PAO) oil. Testing has been performed on these formula-tions using ring-on-ring, shaft/bushing and four ball test techniques. The test results demon-strated significant improvements for tribological characteristics (friction coefficient, extreme pressure failure load and diameter of wear spot) for certain formulations. A strong synergistic effect when using a combination of DND/PTFE additives was observed by a sharp decrease of friction coefficient. It was also demonstrated that using DND with smaller aggregate size (10nm versus 150nm) resulted in better lubricating performance of PAO-based composition.
Substitutionally-Functionalized vs Metallicity-Selected Single-Walled Carbon Nanotubes: A High Energy Spectroscopy Viewpoint
Authors: Ayala Paola , Kramberger Christian , Miyata Yasumitsu , De Blauwe Katrien , Shiozawa Hidetsugu , Follath Rolf , Kataura Hiromichi , Pichler Thomas 
Published: March 2010

AbstractThe unique one-dimensional electronic and optical properties attributed to single-walled carbon nanotubes (SWCNTs) are mainly related to the peculiar local arrangement of sp2 hybridised carbon atoms. This structural configuration gives raise to interesting features, which can be identified with various spectroscopic techniques. In the case of SWCNTs, high energy spectroscopy methods represent effective key tools to analyse the modifications of the underlying basic correlation effects in the bonding environment, the charge transfer between functionalized nanotubes, and on-wall doping. More specifically, in this article we review the shape of the C1s photoemission (PES) response related to the density of states (DOS) of the valence band (VB) in SWCNTs and its changes upon on-wall functionalization and metallicity-sorting. In the last, the progress in the identification of changes in the site selective valence-band electronic structure is clarified in detail.
Synthesis of High Quality Few Layer Graphene Sheets in Large Quantities by Radio Frequency Chemical Vapor Deposition
Authors: Dervishi Enkeleda , Li Zhongrui , Watanabe Fumiya , Shyaka Jimmy , Biswas Abhijit , Courte Aurelie , Umwungeri Jean Luc , Biris Alexandru R. , Biris Alexandru S. 
Published: March 2010

AbstractThis work reports a low-cost method for large scale production of high quality graphene via radio-frequency chemical vapor deposition. High quantities of graphene were successfully synthesized on the Fe-Co/MgO (2.5:2.5:95 wt.%) catalytic system utilizing acetylene as a hydrocarbon source at 1000 °C. The as-produced graphene sheets were purified in a single step by washing with a diluted hydrochloric acid solution under sonication. Next, they were thoroughly characterized by microscopy, spectroscopy, and X-Ray diffraction. Advanced transmission electron microscopy and atomic force microscopy analyses have indicated the formation of 3-5 layered graphene nanosheets. Thorough analyses by Raman spectroscopy were also performed demonstrating the presence of high quality and few-layer graphene samples. This low cost and highly reproducible method may be applied in a straightforward way to produce large quantities of graphene for various advanced applications.
CNTFET Gas Sensors Using SWCNT Mats: Method for Low-cost Fabrication, Solution to Improve Selectivity, Experimental Results using Interfering Agents
Authors: Bondavalli Paolo , Gorintin Louis , Legagneux Pierre , Pribat Didier , Caillier Laurent , Simonato Jean-Pierre 
Published: March 2010

AbstractThe first paper showing the great potentiality of Carbon Nanotubes Field Effect transistors (CNTFETs) for gas sensing applications was published in 2000 [1]. It has been demonstrated that the performances of this kind of sensors are extremely interesting: a sensitivity of around 100ppt (e.g. for NO2 [2]) has been achieved in 2003 and several techniques to improve selectivity have been tested with very promising results [2]. The main issues that have not allowed, up to now, these devices to strike more largely the market of sensors, have been the lack of an industrial method to obtain low-cost devices, a demonstration of their selectivity in relevant environments and finally a deeper study on the effect of humidity and the possible solutions to reduce it. This contribution deals with CNTFETs based sensors fabricated using air-brush technique deposition on large surfaces. Compared to our last contribution [3], we have optimized the air-brush technique in order to obtain high performances transistors (Log(Ion)/Log(Ioff) ∼ 5/6) with highly reproducible characteristics : this is a key point for the industrial exploitation. We have developed a machine which allows us the dynamic deposition on heated substrates of the SWCNT solutions, improving dramatically the uniformity of the SWCNT mats. We have performed tests using different solvents that could be adapted as a function of the substrates (e.g. flexible substrates). Moreover these transistors have been achieved using different metal electrodes (patented approach [4]) in order to improve selectivity. Results of tests using NO2, NH3 with concentrations between ∼ 1ppm and 10ppm will be shown during the meeting.
A Figure of Merit for Transparent Conducting Nanotube Films
Authors: Pekker Aron , Kamaras Katalin , Nemes Norbert , Garcia-Hernandez Mar 
Published: March 2010

AbstractWe propose a wavelength-dependent figure of merit for transparent conducting nanotube networks, composed of the sheet resistance and the optical density. We argue that this would be more useful than previous suggestions, because it relies on more realistic assumptions regarding the optical parameters of real nanotubes.
Electrically Conductive CNT/PTFE Composite Film for Corrosion Resistant Coating on Bipolar Plate of Fuel Cell
Authors: Show Yoshiyuki , Takahashi K. , Nishimura R. , Kohara K. , Fukami Y. , Murata H. 
Published: March 2010

AbstractComposite film of carbon nanotube (CNT) and polytetrafluoroethylene (PTFE) was formed with despersion fluid of CNT and PTFE. The film showed high electrical conductivity in the range of 5-13S/cm. This conductive film was applied on the stainless steel bipolar plate for the polymer electrolyte membrane fuel cell (PEMFC) as anticorrosion film. This coating decreased the contact resistance between the surface of bipolar plate and the membrane electrode assembly (MEA) of the PEMFC. Therefore, the output power of the fuel cell was increased by 1.6 times.
Catalyst-Free GaN Nanowire Nucleation: Correlation of Temperature-Dependent Nanowire Orientation and Growth Matrix Changes
Authors: McElroy Kaylee , Ayres Virginia M , Bieler Thomas R. , Jacobs Benjamin W , Crimp Martin A 
Published: March 2010

AbstractGrowth orientation and type of internal structures are both observed to change abruptly as a function of growth temperature in catalyst free growth of gallium nitride nanowires. In the present work, corresponding temperature-dependent changes in the growth matrix substrate that can affect the availability of nucleation sites and influence the reactivity of constituent adatom materials in catalyst-free nanowire growth are investigated. The influence of Ga vapor pressure and an abrupt change in the availability of single versus molecular adatom constituents is identified as a possible controlling parameter.
Shape Control and Emission-wavelength Extension of InP-based InAsSb Nanostructures
Authors: Lei Wen , Tan H. H. , Jagadish C. 
Published: March 2010

AbstractThis paper presents a study on the shape control and emission wavelength extension of InP-based InAsSb nanostructures. InGaAs buffer, combined with low growth temperature and medium V/III ratio, provides an effective approach to fabricate InAsSb QDs. By using InGaAsSb sandwich layer to serve as both strain reducing layer and metamorphic buffer layer, the emission wavelength of InAsSb QDs can be extended well beyond 2um, which is very useful for their application as mid-infrared emitters.
Mid-infrared Electroluminescence from Surface Plasmon Coupled InAs Quantum Dots
Authors: Passmore Brandon , Adams David , Ribaudo Troy , Wasserman Dan , Lyon Stephen , Shaner Eric 
Published: March 2010

AbstractThe mid-infrared spontaneous emission from intersubband energy transitions in self-assembled InAs quantum dots is demonstrated with plasmonic top contact output couplers. Electrically pumped devices having subwavelength meshes designed to exhibit extraordinary optical transmission from 9 – 12 μm are measured and compared to a reference device with an open area contact. From additional patterning on the top contact, the signal-to-noise ratio was 4 times greater than the reference device. Beyond simply filtering the emission spectra of the quantum dot material, an emission null is observed which we link to the dots being in the near field region of the plasmonic coupler.
Fascinating World of Nanomaterials, Applications and Technology Hurdles in Commercial Production
Authors: Hullavarad Shiva , Hullavarad Nilima 
Published: March 2010

AbstractNanoparticles, nanowires, nanorods and other kinds of nanostructures have been of great interest to scientific field. Semiconducting nanowires have attracted much attention due to the fact that reduced dimensional confinement of electrons, holes and photons make them particularly attractive as potential building blocks for nanoscale optoelectronic devices, highly quantum efficient lasers and non-linear optical converters. It is generally accepted that the low dimensional structures (where the size in one direction is equivalent to or smaller than the de Broglie wavelength) are useful materials for investigating the dependence of electrical and thermal transport or mechanical properties on the dimensionality and quantum confinement. Nanomaterials also play an important role as functional units in fabricating the electromechanical devices. Semiconductor nanostructures of different materials and shapes are investigated due to their size dependent electronic properties observable at dimensions comparable to or less than Bohr radius of exciton in these materials. Especially various oxides and sulphides have generated interests in variety of applications. In this paper, the recent progress in various nanostructures, paradigms in implementation and technology hurdles in implementing nanostructures are discussed
Moving Nanotechnology Toward the Market: Business Strategy and IP Management in the Value Chain
Authors: Giordani Sara 
Published: March 2010

AbstractThe idea that nanotechnologies have the potential to transform different industry sectors and impact on various market segments is receiving large support and contributions from international economic organisations’ reports, research institutions’ newsletters, academics’ and management scholars’ papers and consulting firms’ articles.
The patent landscape, with its burgeoning number of patent filings, and the patent offices worldwide reporting on the increasing number of patent applications in the nanotechnology field, appear as complementary indicators of this trend. As nanosciences research and engineering efforts made feasible the attractive promise of closing the gap between research and industrialization, research outcomes and applications were protected for exclusive exploitation via patent filing and patent portfolio building.
Different Cell Responses on Biologically Inspired Nano-coatings for Orthopedic Applications
Authors: Zhang Lijie , Hemraz Usha D. , Fenniri Hicham , Webster Thomas J 
Published: March 2010

AbstractVarious bone defects, caused by trauma, disease or age-related degeneration, represent a crucial clinical problem all over the world. However, traditional implant materials may cause many complications after surgeries, leading to intense patient pain. Thus, the objective of this in vitro study was to develop a biologically inspired coating on conventional titanium with materials that possess biomimetic nanostructured architectures and favorable surface chemistry. Specifically, self-assembled rosette nanotubes (RNTs) functionalized with various osteogenic peptides and amino acids (such as lysine-arginine-serine-arginine (KRSR), arginine-glycine-aspartic acid (RGD) and lysine (K)) were designed as coatings. Results revealed excellent cytocompatibility properties of these RNTs towards enhancing osteoblast (bone forming cell) and endothelial cell adhesion. In particular, KRSR and RGD functionalized RNTs coated on titanium promoted the greatest osteoblast densities when compared to uncoated titanium. In addition, the KRSR functionalized RNTs selectively improved osteoblast adhesion but not endothelial cell adhesion when coated on titanium. From this study, it can be speculated that the biologically inspired nanotubular structure and osteogenic surface chemistry of RNTs altered the surface properties of titanium to transform it into a more favorable environment for orthopedic applications.
The Impact of Substrate Topography on Cell Filopodia Extension and Cell Spreading
Authors: Yang Lei , Stout David Andrew , Liang Amy , Webster Thomas J 
Published: March 2010

AbstractRecent research has found that cell spreading on materials affects cell functions, including proliferation and differentiation. Also, cell spreading is related to filopodia extension which has been shown to be dependent on substrate topography. To better understand this correlation, live-cell imaging was used here to investigate osteoblast (bone forming cell) filopodia extension and cell spreading on two different kinds of diamond. Nanocrystalline diamond (NCD) and submicron crystalline diamond (SMCD) were fabricated to possess similar surface chemistry but different topographies, consisting of nanoscale spherical grains in NCD and submicron polyhedral grains in SMCD. The filopodia extension and cell expansion results showed that cells on nanoscale topographies had faster filopodia extension and greater expansion area than on submicron topographies. Results indicated that substrate topography has an impact on cell filopodia extension and cell spreading, and NCD promoted filopodia extension and cell expansion better than SMCD.
Nanoengineering of Immune Cell Function
Authors: Shen Keyue , Milone Michael C , Dustin Michael L. , Kam Lance Cameron 
Published: March 2010

AbstractT lymphocytes are a key regulatory component of the adaptive immune system. Understanding how the micro- and nano-scale details of the extracellular environment influence T cell activation may have wide impact on the use of T cells for therapeutic purposes. In this article, we examine how the micro- and nano-scale presentation of ligands to cell surface receptors, including microscale organization and nanoscale mobility, influences the activation of T cells. We extend these studies to include the role of cell-generated forces, and the rigidity of the microenvironment, on T cell activation. These approaches enable delivery of defined signals to T cells, a step toward understanding the cell-cell communication in the immune system, and developing micro/nano- and material- engineered systems for tailoring immune responses for adoptive T cell therapies.