bluuebunny/crossref_metadata_2025_split huggingface dataset:
Low-Frequency Climate Response of Quasigeostrophic Wind-Driven Ocean Circulation
Authors: Abramov Rafail V. , Majda Andrew J. 
Published: September 2011

Abstract
Linear response to external perturbation through the fluctuation–dissipation theorem has recently become a popular topic in the climate research community. It relates an external perturbation of climate dynamics to climate change in a simple linear fashion, which provides key insight into physics of the climate change phenomenon. Recently, the authors developed a suite of linear response algorithms for low-frequency response of large-scale climate dynamics to external perturbation, including the novel blended response algorithm, which combines the geometrically exact general response formula using integration of a linear tangent model at short response times and the classical quasi-Gaussian response algorithm at longer response times, overcoming numerical instability of the tangent linear model for longer times due to positive Lyapunov exponents. Here, the authors apply the linear response framework to several leading empirical orthogonal functions (EOFs) of a quasigeostrophic model of wind-driven ocean circulation. It is demonstrated that the actual nonlinear response of this system under external perturbation at leading EOFs can be predicted by the linear response algorithms with adequate skill with moderate errors; in particular, the blended response algorithm has a pattern correlation with the ideal response operator on the four leading EOFs of the mean state response of 94% after 5 yr. In addition, interesting properties of the mean flow response to large-scale changes in wind stress at the leading EOFs are observed.
Filtering Partially Observed Multiscale Systems with Heterogeneous Multiscale Methods–Based Reduced Climate Models
Authors: Kang Emily L. , Harlim John 
Published: September 2011

Abstract
This paper presents a fast reduced filtering strategy for assimilating multiscale systems in the presence of observations of only the macroscopic (or large scale) variables. This reduced filtering strategy introduces model errors in estimating the prior forecast statistics through the (heterogeneous multiscale methods) HMM-based reduced climate model as an alternative to the standard expensive (direct numerical simulation) DNS-based fully resolved model. More importantly, this approach is not restricted to any analysis (or Bayesian updating) step from various ensemble-based filters. In a regime where there is a distinctive separation of scales, high filtering skill is obtained through applying the HMM alone with any desirable analysis step from ensemble Kalman filters. When separation of scales is not apparent as typically observed in geophysical turbulent systems, an additional procedure is proposed to reinitialize the microscopic variables to statistically reflect pseudo-observations that are constructed based on the unbiased estimates of the macroscopic variables. Specifically, these pseudo-observations are constructed offline from the conditional distributions of the microscopic forcing to the macroscopic dynamics given the macroscopic variables with the method-of-moments estimator. This HMM-based filter is comparable to the more expensive standard DNS-based filter on a stringent test bed, the two-layer Lorenz’96 model, in various regimes of scale gap, including the not so apparent one. This high filtering skill is robust in the presence of additional model errors through inconsistent pseudo-observations and even when macroscopic observations are spatially incomplete.
A Cycloalkane-based Thermomorphic System for Organocatalytic Cyclopropanation Using Ammonium Ylides
Authors: Kim Shokaku , Ikuhisa Naoki , Chiba Kazuhiro 
Published: September 2011

Abstract
Highly polar ammonium ylide intermediates derived from α-halocarbonyl compounds were successfully trapped by cycloalkane phase-tagged activated alkenes via a cycloalkane-based thermomorphic (CBT) process, which allows for facile product isolation using a single liquid–liquid extraction step to effectively generate cyclopropane libraries in the cyclohexane phase.
A Highly Selective Colorimetric Chemosensor for Mn2+ Based on Bis(N-salicylidene)ethylenediamine in Pure Aqueous Solution
Authors: Gou Chao , Wu Haiqiang , Jiang Sisi , Yi Chenglin , Luo Jing , Liu Xiaoya 
Published: September 2011

Abstract
A novel easily available chemosensor 1 based on bis(N-salicylidene)ethylenediamine was reported, which exhibits highly selective and sensitive recognition toward Mn2+ in pure aqueous solution over a wide range of tested metal ions with a clear naked eye color change from colorless to red. This represents the first reported colorimetric chemosensor capable of detecting Mn2+ in aqueous solution.
High efficiency front-illuminated nanotube-based dye-sensitized solar cells
Authors: Li Kangle , Adams Stefan 
Published: September 2011

ABSTRACTA highly reproducible two-step anodization method is reported to fabricate anatase TiO2 nanotube layers. The nanotube membrane fabricated by this method is highly uniform and crack-free. Large area nanotube membranes can be transferred completely onto transparent FTO electrodes without the need for damaging ultrasonic agitation or acid treatment for application in front-illuminated nanotube-based dye-sensitized solar cells. A 16 μm thin front-illuminated nanotube-based dye-sensitized solar cell produced using this method reaches an efficiency of 6.3% under 1 sun illumination AM1.5.
Nanosecond response organic photodiodes: From device physics towards biosensor applications
Authors: Valouch S. , Kettlitz S. W. , Christ N. , Züfle S. , Ögün C. M. , Nintz M. , Lemmer U. 
Published: September 2011

ABSTRACTIn this work we investigate polymer photodiodes based on a blend system consisting of poly(3-hexylthiophene-2,5-diyl) (P3HT) and the fullerene derivative (6,6)-phenyl C-butyric acid methyl ester (PCBM). An optimized low source impedance architecture allows measurements in the GHz range with minimum distortion, while at the same time allowing to probe the favourable sandwich device structure. We have studied the underlying device physics and investigated the influence of parameters such as active layer thickness and bias voltage on the transient photocurrent response. Using a numerical simulation software combining a self-consistent drift-diffusion model in conjunction with an optical model based on the transfer matrix method we model the transient photocurrent of polymer photodiodes. Transient photocurrent measurements utilizing this low impedance device architecture excited by 1.6 ns short laser pulses show very good correlation between simulated and measured results. Furthermore we have developed an encapsulation technique to integrate high-speed organic photodiodes onto standard printed circuit boards (PCBs) to avoid the degradation of the devices by humidity or oxygen.
Fluorescent Nanodiamond – A Novel Nanomaterial forIn VivoApplications
Authors: Mohan Nitin , Zhang Bailin , Chang Cheng-Chun , Yang Liling , Chen Chao-Sheng , Fang Chia-Yi , Hsieh Hsiao-Han , Cho Chun-Yi , Wu Yi-Chun , Weng Jui-Hsia , Chung Bon-chu , Chang Huan-Cheng 
Published: September 2011

ABSTRACTFluorescent nanodiamonds (FNDs) with a size in the range of 10 – 100 nm have been produced by ion irradiation and annealing, and isolated by differential centrifugation. Single particle spectroscopic characterization with confocal fluorescence microscopy and fluorescence correlation spectroscopy indicates that they are photostable and useful as an alternative to far-red fluorescent proteins for bioimaging applications. We demonstrate the application by performingin vivoimaging of bare and bioconjugated FND particles (100 nm in diameter) inC. elegansand zebrafishes and exploring the interactions between this novel nanomaterial and the model organisms. Our results indicate that FNDs can be delivered to the embryos of both organisms by microinjection and eventually into the hatched larvae in the next generation. No deleterious effects have been observed for the carbon-based nanoparticlesin vivo. The high fluorescence brightness, excellent photostability, and nontoxic nature of the nanomaterial have allowed long-term imaging and tracking of embryogenesis in the organisms.
Method for Fabricating Arrays of Graphene Nanoribbons
Authors: Khokhlov Pavel , Lazarev Pavel , Morozov Evgeny 
Published: September 2011

ABSTRACTThis paper discusses recent progress made in developing an advanced sp2 carbon-based materials that can be produced by wet coating as a thin layer and processed to form highly ordered arrays of Graphene Nanoribbons (GNRs) that attach to the substrate on edge with their planes parallel to each other. The fabrication method is based on carbonization of organic molecules spatially preordered in crystalline film on the substrate. This material, named Ribtan, can be used to fabricate GNRs films over large areas that exhibit a very smooth film surface and can form strong covalent bonds to the substrate. The width (film thickness) of Ribtan GNRs can be controlled precisely down to a few nanometers. We demonstrated advantage of Ribtan material for application in supercapacitors as well as feasibility for use in transparent electrodes, solid tribological coatings, and thin film transistors.
Hydrogen from bioethanol: Catalytic honeycombs loaded with Co-Fe/ZnOfor small-scale energy applications
Authors: Ledesma Cristian , Roig Maria , Llorca Jordi 
Published: September 2011

ABSTRACTCatalytic monoliths loaded with ZnO-supported Co-Fe catalysts were prepared in one step by the in situ urea method and tested in the ethanol steam reforming reaction to produce hydrogen. The most active and selective formulation was attained with a Fe/Co molar ratio between 0.05 and 0.1, which showed negligible amounts of methane among the reaction products, thus offering an active and selective material for the low-temperature steam reforming of ethanol for small-scale energy applications.
Lanthanum Oxide Capping Layer for Solution-Processed Ferroelectric-Gate Thin-Film Transistors
Authors: Phan Tue T. , Bui Trinh N. Q. , Miyasako Takaaki , Pham Thanh V. , Tokumitsu Eisuke , Shimoda Tatsuya 
Published: September 2011

ABSTRACTWe report on the use of La2O3 (LO) as a capping layer for ferroelectric-gate thin-film transistors (FGTs) with solution-processed indium-tin-oxide (ITO) channel and Pb(Zr,Ti)O3 (PZT) gate insulator. The fabricated FGT exhibited excellent performance with a high “ON/OFF” current ratio (ION/IOFF) and a large memory window (∆Vth) of about 108 and 3.5 V, respectively. Additionally, a significantly improved data retention time (more than 16 hours) as compared to the ITO/PZT structure was also obtained as a result of good interface properties between the ITO channel and LO/PZT stacked gate insulator. We suggest that the LO capping layer acts as a barrier to prevent the interdiffusion and provides atomically flat ITO/LO/PZT interface. This all-oxide FGT device is very promising for future ferroelectric memories.
Inner composition, defects and morphology of AlGaAs nanowires grown by Au-catalyzed MOVPE
Authors: Prete P. , Buick B. , Speiser E. , Lovergine N. , Richter W. 
Published: September 2011

ABSTRACTThe inner composition, defect content and morphology of AlGaAs nanowires (NWs) grown on (111)B-GaAs by Au-catalyzed MOVPE is reported. The NWs grow tapered with their [111] axis normal to the substrate. The Raman spectra of single AlGaAs NWs were measured in non-resonant conditions with sub-μ-meter spatial resolution, allowing determination of the Al content. NWs consist of GaAs for TG<475°C, but show a two-fold compositional structure for TG >475°C, namely an AlxGa1-xAs core surrounded by an AlyGa1-yAs (y<x) shell, ascribed to the combination of Au-catalyzed (axial) and conventional (sidewall) growth. The cross-sectional shape of AlGaAs NWs changes from triangular (for TG=500÷525°C) to almost hexagonal (for TG=550°C), due to an exchange between $\left\{ {\bar 211} \right\}$ and {110} planes as the slowest to grow. The NWs have free-electron concentrations ∼1018 cm-3, due to Si contamination of the Al source.
ZnO-based transparent anodes for organic light-emitting devices
Authors: Sivaramakrishnan K. , Bakken N. , Alford T. L. 
Published: September 2011

ABSTRACTZnO/Au/ZnO (ZAZ) electrodes grown on flexible PEN substrates were evaluated as transparent electrodes for organic light-emitting devices (OLEDs). OLEDs fabricated with the ZAZ electrodes showed reduced leakage in contrast to control OLEDs on ITO and reduced ohmic losses at high current densities. At a luminance of 25000 cd/m2, the lum/W efficiency of the ZAZ electrode based device was 5% greater than for the device on ITO. The ZAZ electrodes also allow for a broader spectral output in the green wavelength region of peak photopic sensitivity compared to ITO. The results have implications for electrode choice in display technology.
Partially Hydrogenated Graphene: Semiconductor Material with a Tunable Gap and Its Non-Destructive Optical Characterization
Authors: Gaspari F. , Shkrebtii A.I. , McNelles P. , Cabellos J.L. , Mendoza B.S. 
Published: September 2011

ABSTRACTWe report first principles modeling of partially hydrogenated graphene, with a variety of hydrogen induced superstructures. The dependence of the optical gap on hydrogen content and coverage is examined, to assess the best configurations suitable for optoelectronic applications. Electron and optical DFT LDA gaps in the range between 0.2 and 1.5 eV were obtained for low hydrogen coverage. For such systems, hydrogen clustering (by saturating neighbouring C dangling bonds at the opposite sides of the graphene sheet) is energetically most favourable and generally produces larger gap. More homogeneous H distribution one-side bonded to C-host atoms is, in contrast, less energetically favourable or even structurally unstable and generally produces smaller gap. In addition, ordering of hydrogen was observed at 50% of H, that offers a possibility of transforming 2D graphene to an array of 1D nanowires Calculated linear optical anisotropy and nonlinear second harmonic generation (this will be discussed in a forthcoming paper) indicate these are not only gap sensitive, but can provide an access to microscopic details of the 2D nano-sheets such as symmetry, hydrogen induced structure, degree of hydrogenation, chemical bonding and many others, all promising for device application. The approach developed can be used for graphene/ graphane single layer or bilayer, formed on top of various substrates, where experimental geometries may not provide conditions for complete hydrogenation of the 2D nano-sheet(s).
Biofuels: The Role of Biodiesel and Improving Its Performance
Authors: Knothe Gerhard 
Published: September 2011

ABSTRACTConcerns about the availability and long-term supply of petroleum-derived fuels have caused the search for alternative sources of energy. Liquid fuels will for some applications be necessary for an indefinite period of time. Therefore, defining relevant feedstocks, producing fuels from these feedstocks and the properties of these fuels are critical issues. Fuels powering compression-ignition (diesel) and turbine (jet) engines are among these liquid energy sources. Biodiesel, defined as the mono-alkyl esters of vegetable oils, animal fats or other triacylglycerol-based feedstocks plays a prominent role in this connection as alternative to petrodiesel fuels. Important issues facing biodiesel are feedstock supply as not enough vegetable oil is available to replace the whole petrodiesel market and the issue of fuel properties, especially cold flow and oxidative stability. The search for additional feedstocks coupled with the food vs fuel issue has increased interest in inedible oils derived from sources such as used cooking oils, jatropha and algae. However, biodiesel from these sources, as biodiesel derived from classical sources such as commodity vegetable oils, must meet performance criteria and this is not necessarily the case. Therefore, modifying the composition of biodiesel, i.e., its fatty ester profile, is a critical issue to enhance its use in the marketplace. Esters of specific fatty acids impart improved properties to biodiesel with esters of decanoic and palmitoleic acid displaying favorable properties for enrichment in biodiesel feedstocks. Renewable diesel is another fuel that can be obtained from triacylglycerol-based feedstocks. In its composition, i.e. alkane-type hydrocarbons, it more closely resembles petrodiesel fuel. While biodiesel is obtained from triacylglycerol-based feedstocks via a transesterification reaction using an alcohol in presence of a catalyst under mild conditions, renewable diesel can be obtained from such feedstocks via a hydrodeoxygenation reaction using hydrogen in presence of a catalyst under more severe conditions. Biodiesel and renewable diesel are compared regarding their production and properties and it is suggested that each fuel has a role to play in an alternative energy mix based on its properties.
DNA as an Engineering Material: From Assembly to Computation on Silicon
Authors: Akin Hayri E. , Zhong Jiebin , Penchev Miroslav , Ozkan Cengiz S. , Ozkan Mihrimah 
Published: September 2011

ABSTRACTDNA possesses inherent recognition and self-assembly capabilities, making it attractive templates for constructing functional material structures as building blocks for nanoelectronics. Here we report the use of DNA towards the assembly and electronic functionality of nanoarchitectures based on conjugates of carbon nanotubes (CNTs), nanowires (NWs) and DNA computing on Si-CMOS platform. First, assembly of CNTs with DNA is demonstrated and electrical measurements of these nanoarchitectures demonstrate negative differential resistance in the presence of CNT/DNA interfaces, which indicates a biomimetic route to fabricating resonant tunneling diodes. End-to-end assembly of NWs is realized with designed DNA sequences and process is carried on silicon CMOS based microarray platform. Second, this microarray platform is adopted to perform DNA computing. To begin with, the information present in an image is encoded through the concentrations of various DNA strands via selective hybridization and decoded on microarray to recreate the original image. Lately, various satisfiability (SAT) problems, which has long served as a benchmark problem in DNA computing, are solved on this platform via DNA. The goal in a SAT Problem is to determine appropriate assignments of a set of Boolean variables with values of either “true” or “false” such that the output of the whole Boolean formula is true. Other than making 1st time silicon compatible DNA computing, our studies make us understand bio molecules, especially DNA has various advantages for future hybrid technologies.
Synergistic effects on band gap-narrowing in titania by doping from first-principles calculations: density functional theory studies
Authors: Long Run , English Niall J. 
Published: September 2011

ABSTRACTThe large intrinsic band gap in TiO2 has hindered severely its potential application for visible-light irradiation. We have used a passivated approach to modify the band edges of anatase-TiO2 by codoping of X (N, C) with transition metals (TM=W, Re, Os) to extend the absorption edge to longer visible-light wavelengths. It was found that all the codoped systems can narrow the band gap significantly; in particular, (N+W)-codoped systems could serve as remarkably better photocatalysts with both narrowing of the band gap and relatively smaller formation energies and larger binding energies than those of (C+TM) and (N+TM)-codoped systems. Our theoretical calculations help to rationalise experimental results and provide reasonably meaningful guides for experiment to develop more powerful visible-light photocatalysts.
Alloy Oxide Electrocatalysts for Regenerative Hydrogen-Halogen Fuel Cell
Authors: Mondal Sujit K , Rugolo Jason , Aziz Michael J. 
Published: September 2011

ABSTRACTStable, catalytically active, and inexpensive halogen electrodes are essential for the success of the regenerative hydrogen-halogen fuel cell as a competitive means of large-scale electricity storage. We report the synthesis and electrochemical testing of two novel electrode materials — ruthenium-cobalt and ruthenium-manganese alloy oxides. These alloys were fabricated by wet chemical synthesis methods as a coating on a titanium metal substrate and tested for chloride and bromide oxidation and for chlorine and bromine reduction. These alloy oxides exhibit high catalytic potency and good electrical conductivity good stability, while having a significantly reduced precious metal composition compared to commercial chloride oxidation electrodes made of the oxide of a ruthenium-titanium alloy. We tested alloys with Ru content as low as 1% that maintained good electrochemical activity. Stability tests indicate immeasurably small mass loss.
Comparison of ion beam and electron beam induced transport of hot charge carriers in metal-insulator-metal junctions
Authors: Hopster Johannes , Diesing Detlef , Wucher Andreas , Schleberger Marika 
Published: September 2011

ABSTRACTThe generation of hot charge carriers within a solid bombarded by charged particles is investigated using biased thin film metal-insulator-metal (MIM) devices. For slow, highly charged ions approaching a metal surface the main dissipation process is electronic excitation of the substrate, leading to electron emission into the vacuum and internal electron emission across the MIM junction. In order to gain a deeper understanding of the distribution and transport of the excited charge carriers leading to the measured device current, we compare ion induced and electron induced excitation processes in terms of absolute internal emission yields as well as their dependence on the applied bias voltage.
First Principles Analysis of Ultra-Thin Silicon Films with Dimer Structures
Authors: Kamiyama Eiji , Sueoka Koji 
Published: September 2011

ABSTRACTThe impact of dimer formations at the surfaces of the internal atoms of silicon (Si) thin film was evaluated by examining silicon-on-insulator (SOI) and plate models. In the SOI models, a dimer formation was modeled at one side of the Si thin film. The plate models had two dimers at each surface, which had been considered as a Si bulk model in previous studies. First principles calculation showed that the deviations of Si atoms from the first to fourth layers of the SOI models did not differ remarkably from those of the plate models. The internal atoms deeper than the fifth layer showed near-zero deviation in some of the SOI models and had evident non-zero deviation in the other SOI models. All the SOI and plate models showed lower Si atom self-energy than in the Si bulk. The layer-to-layer distance of internal atoms in the films became longer than that of atoms in Si bulk. These results indicated that (i) Si films with dimer surfaces are relaxed by deviations in the whole film, and (ii) even the thick plate model with 32 layers dose not reveal the nature of Si bulk.
Semiconducting Polymer and Hydrogenated Amorphous Silicon Heterojunction Solar Cells
Authors: Middya A. R. , Schiff Eric A. 
Published: September 2011

ABSTRACTIn this work, we report on investigation of p-type semiconducting polymer, {poly(3,4 polyethylenedioxythiophene)-poly(styrenesulfonate)} (PEDOT:PSS) as the p-layer in NIP and PIN hydrogenated amorphous silicon (a-Si:H) solar cells. The rectification ratio of solution-casted diode is ∼ 10, it increases to 3×104 when PEDOT:PSS is deposited by Spin Coating technique. We observed additional photovoltaic effect when light is illuminated through polymer side. So far, best solar cells characteristics observed for PEDOT:PSS/a-Si:H hybrid solar cells are Voc ≈ 720 mV and Jsc ≈ 1 - 2 mA/cm2.