bluuebunny/crossref_metadata_2025_split huggingface dataset:
Directly Measuring the Adhesive and Elastic Properties of Bacteria using a Surface Force Apparatus: Effect of Desiccation
Authors: Heo Cheol Ho , Maier Raina M , Curry Joan E 
Published: April 2011

ABSTRACTBacterial adhesion is the first step in biofilm formation which impacts numerous environmental, industrial and medical processes. Examples of undesirable consequences of biofilm formation include metal rust, sewage sludge and bacteria-related diseases. Desirable consequences are biofiltration and bioremediation. Bacteria are resilient and can survive in harsh environments. A severe stress is desiccation since dehydration can damage DNA and change the properties of proteins. Some bacteria protect against dehydration by accumulating sugars such as sucrose and trehalose while others undergo a transformation from an active to a dormant state. Evaporative deposition of bacteria on a surface shows that some bacteria aggregate to form two dimensional patterns which may be important for nutrient sharing and survival in dry conditions. Since bacteria are increasingly being employed as components in biosensors and biofilm reactors, it is important to understand the material properties of bacteria in dry conditions for these applications. For a decade, Atomic Force Microscopy (AFM) has been the primary tool used to study the adhesion and elastic properties of individual bacteria. In this work we show it is possible to use a Surface Forces Apparatus (SFA) to measure elastic and adhesive properties of small collections of surface bound bacteria. The measurements are conducted with incomplete, patterned bacterial films and we have developed a protocol to image the contact area with AFM after the experiment. Using the SFA, we measured the force profile between aPseudomonas aeruginosaPAO1 film and a bare mica surface.P. aeruginosaPAO1 is a ubiquitous gram-negative soil bacterium and is also an opportunistic pathogen. We repeated the measurement in the same contact position for six days to determine the effect of desiccation on the film material properties.
Processing of Dense Nanocrystalline Zirconia Thin Films by Sol-Gel
Authors: Peters Christoph , Bockmeyer Matthias , Krüger Reinhard , Weber André , Ivers-Tiffée Ellen 
Published: April 2011

ABSTRACTVia metal organic deposition (MOD) sapphire substrates were multiple dip-coated with a molecular dispersive 8 mol% Y2O3 doped ZrO2 (8YSZ) sol to prepare dense, crack-free thin films. The thin films were consecutively exposed to a tempering program with several rapid thermal annealing (RTA) steps and a final dwell temperature between 500 °C and 1400 °C for 24 h. Grain growth, phase, stoichiometry and macroscopic density of the thin films were analyzed by XRD and SEM. Grain sizes ranged between a few nanometers in diameter at 500 °C and several hundreds of nanometers at 1400 °C.
Strengthening Nanoscience Education through Multidisciplinary Collaborations
Authors: Cosby Ronald M 
Published: April 2011

ABSTRACTRecent collaborations with science and engineering faculty in major research universities have dramatically increased and strengthened research and educational opportunities in nanoscience and nanotechnology at Ball State University. The three-year Center for Computational Nanoscience (CCN) project involved eleven co-principal investigators from three disciplines (physics, chemistry, electrical engineering) and five universities, including Ball State University, University of Notre Dame, Ohio University, Purdue University, and Valparaiso University. Funded by the Indiana 21st Century Research and Technology Fund, this $1.5 million project focused on theoretical and computational investigations of the electrical and optical properties of quantum dots and included partial support for software development for the Purdue NanoHub, a web-based software repository. The effects of this collaborative project (and previous contacts) on nanoscience education and research at the undergraduate and master's levels in the Department of Physics & Astronomy at Ball State University have been extensive and are described in this paper. University and community impacts include an enhanced awareness of nanoscience and nanotechnology.
Excellent Room-Temperature Ferroelectricity in Mn-substituted BiFeO3 Thin Films Formed by Chemical Solution DepositionΨ
Authors: Singh Sushil Kumar , Ishiwara Hiroshi 
Published: April 2011

AbstractMn-substituted BiFeO3 (BFO) thin films were formed by chemical solutions deposition on Pt/Ti/SiO2/Si(100) structures. Effects of the Mn-substitution on the structure and ferroelectricity of BFO films were examined. We found that the lattice structure of the film is sensitive to the Mn-substitution and the secondary phase is appears in 50% Mn-substituted BFO films. The leakage current were increased with the Mn-substitution. However, the 5% Mn-substituted BFO film shows low leakage current than undoped BFO films in a high electric field than 0.5 MV/cm. Due to the low leakage current in Mn-doped 3, 5 and 7% BFO films, the saturated P-E hysteresis loops with remanent polarization around 100 μC/cm2 were obtained at RT.
Oxidation of Structured Silicon Thin Films for Inverse Silicon Square Spiral Photonic Crystal Fabrication
Authors: Summers Mark Alan , Brett Michael J 
Published: April 2011

ABSTRACTPhotonic Band Gap (PBG) crystals are artificially engineered structures of periodically alternating dielectric materials that enable manipulation of light in unique ways. As proposed by O. Toader and S. John, large bandwidth PBG crystals based on the diamond lattice can be constructed by fabricating a two-dimensional periodic array of silicon square spirals. Furthermore, an improved photonic crystal can be constructed by fabricating the inverse of this structure, such that void square spirals are situated in a silicon backfill. This structure yields a theoretical maximum PBG of 24%, while the direct silicon square spiral structure yields a theoretical maximum of 16%. [1]The direct silicon square spiral structure has previously been successfully fabricated using the glancing angle deposition (GLAD) process [2]. The GLAD fabrication process uses advanced substrate motion and oblique incidence deposition to engineer precise nanostructures such as helices, chevrons, or polygonal spirals. These nanostructures are grown with lateral and longitudinal periodicity using a pre-patterned substrate consisting of a tetragonal array of relief structures.Upon successful fabrication of the direct silicon square spiral structure, it was proposed that fabrication of the inverse structure could be completed using a backfill process with a silica template [2]. A periodic array of silica square spirals would be fabricated using the GLAD technique. The template would then be filled with amorphous silicon using low-pressure chemical vapour deposition (LPCVD). To reveal the inverse silicon structure, the silica template would be removed by means of chemical etching with an isotropic chemical etchant. Creation of a suitable template for the inversion of silicon square spirals is an important step in the realization of the inverse silicon square spiral PBG crystal. However, we have seen empirically that silica square spiral films grown directly via the GLAD technique are structurally inferior to silicon films. We present an intermediate step for the fabrication of a suitable template, whereby a silicon structure is fabricated with appropriate geometries and subsequently oxidized. The procedure has been optimized to ensure a thorough oxidization of the silicon posts, while minimally distorting the structure of the square spiral template.
Adhesion Property of ITO Film on Polymer Treated by Linear Ion Source
Authors: Hsiao Shih Hsiu , Tanaka Yoshikazu , Ide-Ektessabi Ari 
Published: April 2011

ABSTRACTIndium oxide doped with tin oxide, ITO, has been extensively used as the transparent conductive electrode in display industry, and also been utilized on polymeric substrate for flexible display. The polymeric material used in flexible display has its flexibility and lightweight compared to glass-based substrate. However, it does not completely meet with the requirements in mechanical properties. The ion irradiations modify the polymeric surface that can be expected to improve its adhesion property. In this study, linear ion source was developed to treat the polymeric surface, and then ITO thin film was deposited by sputter deposition commonly utilized in display industry. Atomic Force Microscope was used to analyze the physical transformation of surface structure after the various argon and oxygen ion irradiated. Finally, the scratch testing showed the adhesive strength improved between ITO thin film and polymeric substrate when surface modified by optimum ion irradiation. Moreover, linear ion source provides the good uniformity of surface treatment and is very suitable for production-scale process.
Fabrication of Organic Thin Film Transistor Based on the Ink-Jet Printed Electrodes of Nano Silver Particles
Authors: Kim Dongjo , Jeong Sunho , Lee Sul , Park Bong-Kyun , Moon Jooho 
Published: April 2011

ABSTRACTIn this work, we here developed a conductive ink which contains silver nano-particles from which the electrodes for organic thin film transistor were directly patterned by ink-jet printing. Nano-sized silver particles having ∼ 20nm diameter was used for the direct metal printing. Silver conductive ink was printed on the heavily doped n-type silicon wafer with 200-nm thick thermal SiO2 layer as a substrate. To achieve a high line resolution and smooth conductive path, the printing conditions such as the inter-drop distance, stage moving velocity and temperature of the pre-heated substrates were optimized. After the heat-treatment at temperatures of about 100 ∼ 300 ° for 30 min, the printed silver patterns exhibit metal-like appearance and the conductivity. To fabricate a coplanar type TFTs, an active material of semiconducting polymer, which was dissolved in a proper solvent, was deposited between the ink-jet printed silver electrodes by solution process. The output and transfer characterization was measured in air. The OTFT with the ink-jetted source/drain electrodes show a mobility of 1.3 × 10−3 cm2 V−1 s−1 in the saturation regime and on/off current ratio over 103 and a threshold voltage of about −13 V.
Polymer-Clay Hybrid Dielectric Layer for Flexible Organic Thin Film Transistors
Authors: Uemura Sei , Suemori Koji , Yoshida Manabu , Hoshino Satoshi , Kodzasa Takehito , Kamata Toshihide 
Published: April 2011

ABSTRACTA polymer field-effect transistor (FET) was fabricated with poly(3-hexylthophene) as an active layer and poly(methyl-methacrylate) gate dielectric modified with poly(vinyl alcohol). The influences of air atmosphere on the FET property were investigated. Under the air atmosphere, FET properties such as modulation of drain current by gate bias, leakage current and threshold voltage shift were strongly influenced by humidity. An influence was investigated by temperature dependence of FET properties. It cleared the relationship between the FET property and intrinsic mobile ion in the gate dielectric. The influence of humidity on the FET property can be prevented by insertion of a clay mineral layer, which clogs motion of ion transport in gate dielectric layer.
Connecting Curable Siloxanes to Luminescent Organic Semiconductors - Monomers for Functional Hybrid Materials
Authors: Detert Heiner , Sugiono Erli 
Published: April 2011

ABSTRACTLuminescent stilbenoid chromophores with two alkoxysilane end groups are prepared via hydrosilylation or condensation / reduction of substituted 5-ring OPVs with hydro- and aminopropylsilanes. Chromophore and curable units are connected via flexible spacers. To obtain compounds with a rigid connection between silane and π-system, iodo- or bromo-OPVs were coupled to alkoxysilanes carrying vinyl- or p-vinylphenyl moieties under Heck conditions. This approach allowed a combined connection of the chromophore to the silane moiety with an extension of the π-system. Hydrolysis of the alkoxysilanes yields silanols condensing to curable three-dimensional networks, thus allowing the transformation of small molecules to transparent and fluorescent films with well-defined chromophores.
Bias Dependent TMR in Fe/MgO/Fe(100) Tunnel Junctions
Authors: Rungger Ivan , Rocha Alexandre Reily , Mryasov Oleg , Heinonen Olle , Sanvito Stefano 
Published: April 2011

ABSTRACTWe calculate from first principles the I-V characteristics of Fe/MgO/Fe(100) tunnel junctions. In particular we compare the zero-bias transmission with self-consistent calculations at finite bias. In the case the magnetizations of the two Fe layers are parallel to each other, at small bias there is a significant contribution to the transmission coming from the minority spin channel. This is due to a sharp resonance in the transmission coefficient close to the Fermi level, originating from a surface state. As a bias exceeding 25 mV is applied, the surface states get out of resonance and the current through the minority spin channel saturates, so that the current flows mainly through the majority channel. The same effect is not present for the antiparallel alignment of the magnetization with the net result of large TMR at low bias, which then saturates for a bias larger than 25 mV.
Ferroelectric-Specific Peptides as Building Blocks for Bio-Inorganic Devices
Authors: Reiss Brian Dennis , Ocola Leonidas , Auciello Orlando , Firestone Millicent A. 
Published: April 2011

ABSTRACTThe integration of biomolecules with inorganic materials to create functional composites represents a critical step in the development of next-generation biosensors, micro/nanofluidic devices, and biochips that require a combination of abiotic (inorganics) and biotic (proteins, DNA, antibodies) components. Toward this end, we have previously applied combinatorial phage display techniques to identify a constrained heptapeptide sequence (CISLLHSTC) that selectively binds to a perovskite ferroelectric (MOCVD-deposited lead zirconium titanate, PZT). In this work, we examine the binding of this heptapeptide sequence, prepared by solid phase peptide synthesis to sol-gel PZT. In particular, the surface roughness has been examined and the long-term stability of the PZT films in biological buffered aqueous solutions by atomic force microscopy, X-ray diffraction and P-E hysteresis loop. In addition, the selectivity of the peptide binding to PZT has been determined by immunofluorescence microscopy and the nature of peptide binding to the PZT surface is probed by X-ray photoemission spectroscopy.
The Design and Control of Catalytic Motors: Manipulating Colloids and Fluids with Self-Generated Forces
Authors: Kline Timothy R. , Iwata Jodi , Lammert Paul , Velegol Darrell , Mallouk Thomas , Sen Ayusman 
Published: April 2011

ABSTRACTMicrofabrication was employed to pattern silver (Ag) on a gold (Au) surface. The two metals served as bimetallic heterogeneous catalysts for the heterogeneous decomposition of H2O2. Silver was the cathode, carrying out H2O2 reduction (to water) and gold the anode carrying out H2O2 oxidation (to oxygen). Both protons and electrons are created at the anode (as a part of the reaction) and migrate to the cathode (migration of ions is a current) where they are consumed. Thereby establishing an electric field (migration of ions obeys Ohm's law), which passively pumps fluids through electroosmosis. Electrophoresis also present as either an additive component to the electroosmotic flow or results in pattern formation (occurs at point where electroosmosis is equal and opposite to that of electrophoresis). Herein, the electrokinetic model is further tested and validated as chemical methods to tune the tracer behavior (convection to pattern formation), design of asymmetric patterns through microfabrication and attempts to indirectly measure the electric field were successful.
Influence of CNT on the Crystallization Behavior of P(VDF-CTFE) Copolymers
Authors: Shan Xiaobing , Li Suiqiong , Yang Xin , Cheng Zhongyang 
Published: April 2011

ABSTRACTP(VDF-CTFE) based nanocomposites were prepared by mixing the polymer with carbon nanotube (CNT) or C60 using solution cast method. The volume fraction of the CNT or C60 was from 0.1 % to 1.0%. The influence of CNT and C60 on the crystallization behavior of P(VDF-CTFE) was determined using XRD and DSC as well as the P-E loop. It is found that the CNT or C60 enhances the β-phase and the crystallinity. The crystallinity process in the composites was studied using DSC.
Dielectric characteristics of Poly(chloro-p-Xylene) thin films for high energy density pulsed power capacitors
Authors: Tewari Pratyush , Furman Eugene , Lanagan Michael T. 
Published: April 2011

ABSTRACTPoly(chloro-p- Xylene) or Parylene –C thin films are particularly attractive for dielectric as well as biomedical applications. In the current work the dielectric properties of Parylene-C thin films are investigated to form laminar composites with oxide thin films for high energy density pulsed power capacitors. Parylene-C thin films were synthesized by pyrolytic vapor decomposition polymerization of dichloro-di(p-Xylene) monomer. Annealing of films at 225°C has shown to enhance crystallinity of film. Conduction in Parylene-C thin films appears to be bulk-controlled with the hopping charges contributing to leakage current. The barrier height of 0.89eV and hopping distance of 2 - 2.5nm are physically plausible and similar to previously reported values in polymer literature.
Fabrication and Characterization of a Poly (3-Hexylthiophene) Thin Film Micro-sensor for Hypergolic Vapor Detection
Authors: Shu Huihua , Wan Jiehui , Shu John , Yang Hong , Chin Bryan A. 
Published: April 2011

ABSTRACTA passive chemiresistor micro-sensor was investigated for the detection of hydrazine compounds. Hydrazine compounds are a highly toxic and carcinogenic species exhibiting toxic effects in humans at very low levels of exposure. Therefore, a sensor capable of detecting ppb levels of hydrazine compounds is required to insure the safety of personnel. The present study describes the fabrication, testing, and characterization of a low-cost, ultrasensitive Poly (3-Hexylthiophene) (P3HT) thin film-based micro-sensor for the detection of hydrazine compounds. Standard microelectronic manufacturing techniques were used to form a micro-sensor composed of a silicon substrate, interdigitated gold electrodes, and P3HT sensing film. Responses of the micro-sensor to hydrazine compounds at different temperatures and concentration levels are reported. When exposed to 25 ppm hydrazine in nitrogen, the sensor's resistance was measured to change from a few ohms to over 10 Megaohms. The thermal stability of the P3HT micro-sensor and the method to improve thermal stability are also explored. Thermally annealing the P3HT micro-sensor was found to improve thermal stability at high temperatures. Moreover, the sensor exhibits good specificity to hydrazine and does not respond to the presence of NO2 and/or N2O.
Photonic-Fluidic Integrated Microstructures for Sensor and Photonic Device Applications
Authors: Callender Claire L. , Dumais Patrick , Ledderhof Christopher J. , Noad Julian P. 
Published: April 2011

ABSTRACTThe design, fabrication and characterization of liquid-filled microchannels embedded in silica layers and integrated with optical waveguides for applications in on-chip sensors and novel photonic devices are presented. These integrated microstructures are formed using plasma-enhanced chemical vapor deposition (PECVD), photolithography and reactive ion etching (RIE). Surface accessible fluid introduction ports have been developed, and microfluidic circuits including bends, T-junctions and splitters are demonstrated. Coupling of light from integrated solid silica waveguides via directional coupling or direct end-fire coupling into fluid filled channels has been achieved on-chip, and optical losses assessed experimentally and theoretically. Optimization of the microstructures for sensor applications and for novel photonic devices based on nonlinear and other optical properties of fluids in integrated liquid waveguide segments is discussed.
Plasmonic and Diffractive Coupling in 2D Arrays of Nanoparticles produced by Electron Beam Lithography
Authors: McLellan Erin , Gunnarsson Linda , Rindzevicius Tomas , Kall Mikael , Zou Shengli , Spears Kenneth , Schatz George , Van Duyne Richard 
Published: April 2011

ABSTRACTNanofabrication is one of the driving forces leading to developments in a variety of fields including microelectronics, medicine, and sensors. Precise control over nanoscale architecture is an essential aspect in relating new size-dependent material properties. Both direct write methods and natural lithography's offer a unique opportunity to fabricate “user-defined” writing of nanostructures in a wide range of materials. Electron Beam Lithography (EBL) and Nanosphere Lithography (NSL) provide the opportunity to fabricate precise nanostructures on a wide variety of substrates with a large range of materials. Using electrodynamics calculations, Schatz and coworkers have discovered one and two dimensional array structures that produce remarkably narrow plasmon resonance spectra upon irradiation with light that is polarized perpendicularly to the array axis. In order to investigate these interactions, precise control of nanoparticle orientation, size, shape and spacing is necessary. If the overall structures have excessive defects then the effect may not be seen. For the two dimensional arrays, to have the best control over array fabrication and to look at these interactions experimentally, EBL was used to construct both hexagonal arrays of circular cylinders and the Kagome lattice. The interparticle spacing in each of these structures was varied systematically. Dark field microscopy was used to look at overall sample homogeneity and collect the single particle plasmon resonance spectrum. Additionally, both dark-field and extinction spectroscopies were used to look at the bulk spectral properties of each array type and each spacing. In investigating of the two dimensional arrays, the Kagome structure was also compared to samples produced by traditional NSL to study the optical interaction of defects, domains, and overall sample uniformity on the shape and location of the plasmon resonance. This work illustrates a deeper understanding in the nature of the optical coupling in nanostructures and this knowledge can be utilized in the future to fabricate designer (tailor made) substrates for plasmonic and surface-enhanced raman applications.