bluuebunny/crossref_metadata_2025_split huggingface dataset:
Self-Assembling Nanostructures: Recognition and Ordered Assembly in Protein-Based Materials
Authors: McGrath Kevin P. , Kaplan David L. 
Published: March 2011

AbstractA new approach to materials design is presented, utilizing specific recognition and assembly at the molecular level. The approach described exploits the control over polymer chain microstructure afforded by biosynthesis to produce proteinbased materials with precisely defined physical properties. Incorporated into these materials are recognition elements that stringently control the placement and organization of each chain within higher order superstructures. The proteins, designated Recognin A2 through Recognin E2, are recombinant polypeptides designed de novo from both natural consensus sequences and an appreciation of the physical principles governing biological recognition. These materials are designed to examine the forces involved in specific recognition and complexation. through control of charge identity and placement, a pattern for specific interaction can be introduced. A subset of these materials are programmed to spontaneously assemble into complex, multicomponent structures and represent the first step in a rational approach to nanometer-scale structural design.
Over-Expression of a Core Repeat from an Insect Silk Protein that forms Intramolecular Disulfide Bonds
Authors: Smith Stanley V. , Case Steven T. 
Published: March 2011

AbstractA gene encoding one complete [C+SR] core repeat from spIa, a 1000-kDa silk protein from Chironomus tentans, was synthesized and its recombinant protein expressed to high levels in bacterial cells. We observed that reducing agents significantly alter the electrophoretic mobility of this protein. A variety of data indicate that the purified recombinant protein is folded and its structure stabilized by two intramolecular disulfide bonds.
Cloning and Expression of a Synthetic Mussel Adhesive Protein inEscherichia Coli
Authors: Salerno Anthony J. , Goldberg Ina 
Published: March 2011

AbstractRepetitious gene cassettes that encode the consensus decapeptide repeat ofMytilus edulisbioadhesive protein were cloned and expressed inEscherichia coli. The bioadhesive precursor (BP, Mx−25,000) was expressed from one 600-bp gene comprised of a 30-bp unit repeat. The repetitious gene appeared stable in a T7-based host/vector system.Using the T7 expression system for induction, BP was produced at levels approaching 60% of total cell protein. BP was found both in intracellular inclusions and in the soluble fraction. Interestingly, methionine was processed from the N-terminus of the purified protein to give an authentic consensus precursor protein.
Development of Electrically Conductive Poly(3-Hexylthiophene) as a thin Film Sensor for Hydrazine Vapor
Authors: Ellis D. L. , Zakin M. R. , Bernstein L. S. , Rubner M. F. 
Published: March 2011

AbstractThin films of the electrically conducting polymer, poly(3-hexylthiophene) (P3HT), were developed as sensors for hydrazine vapor at the part-per-billion level. The P3HT films were fabricated by a spin coating technique onto quartz substrates incorporating gold interdigitated electrodes, and were rendered conductive by doping with an NOPF6 solution. The sensors respond strongly and instantaneously to hydrazine concentrations as low as 1 part-per-billion with a measurement accuracy of ±20%. In addition, the sensors exhibited excellent environmental stability, long shelf life, and good interference rejection.
Core Level Orbital Interactions and Fast Ion Conduction
Authors: Oliveria M. , Johnson K. H. 
Published: March 2011

AbstractAlthough there has been much success in theoretical modelling of fast ion conductors with molecular dynamics simulations, there has been less attention paid to development of a chemical understanding of fast ion conduction. In this paper we explore the importance of core level interactions and the role that they play in constructing high diffusivity paths in solids. In particular, we have carried out molecular orbital calculations (using the self-consistent-field X-alpha scattered-wave method) on AgI clusters to examine the orbital interactions of the filled Ag 4d level. We hypothesize that it is the interaction of the d electrons that is responsible for fast ion conduction in AgI and other Ag and Cu binary fast ion conductors. The results of these calculations will be compared with other electronic structure calculations and XPS data.
Non-Debye Relaxation Process of Hopping Ionic Conduction in Lattice Gas Models
Authors: Sato Hiroshi , Datta Anuradha 
Published: March 2011

AbstractBased on the examination of the relaxation process of the motion of a single particle in the assembly of particles of the same species, it is shown that the relaxation process of the motion of a particle in a lattice gas model is intrinsically non-Debye. The origin of this effect is traced to the deviation of the motion of particles from equilibrium immediately after their jumps.
Structure, Fragmentation, and Phonons in Silicon Microclusters
Authors: Li Wei , Kalia Rajiv K. , Vashishta Priya 
Published: March 2011

AbstractMolecular-dynamics simulations are performed to investigate structures, vibrational spectra, and fragmentation channels of silicon microclusters ranging in size from 32 to 52 atoms. Structural information is derived from pair-distribution functions, bond-angle distributions, and the structure and statistics of rings. Molecular-dynamics simulation results for energetics suggest that 33, 39, 45 and 51 atom clusters are highly stable. These magic-number clusters have predominantly five and six membered rings. With an increase in “temperature”, most clusters tend to fragment by loosing one atom at a time. Vibrational densities of states of 32-52 atom silicon clusters show only minor deviations from the bulk behavior.
Oxygen Ion Conductivity in a New Class of Layered Bismuth Oxide Compounds
Authors: Thomas Julie K. , Anderson Mairin E. , Krause Wendy E. , Loye Hansconrad Zur 
Published: March 2011

AbstractCompounds that consist of intergrowths between the Aurivillius phase Bi4Ti3O12 and brownmillerite-like slabs of BaMO2.5were synthesized and their oxygen ion conductivities investigated. Both BaBi4Ti3ScO14.5 and BaBi4Ti3InO14.5 display a discontinuity in their Arrhenius plots that appears to be caused by an oxygen vacancy order-disorder transition. Conductivity data for two Aurivillius phases BaBi4Ti4O15 and BaBi2Nb2O9 are included for comparison.
Ruthenium Doped Gadolinium Titanate: Effects of a Variable Valent Acceptor on Ionic and Electronic Conduction
Authors: Spears M.A. , Tuller H.L. 
Published: March 2011

AbstractWe have investigated ruthenium doped gadolinium titanate, Gd2(RuxTi1-x)2O7-δ with 0 ≤ x ≤ 0.2, to determine the role of variable valent Ru in influencing the defect structure and transport properties of the pyrochlore host. We have developed a defect chemical model to interpret electrical conductivity, thermoelectric power, and thermogravimetry data. We have found that Ru acts as an acceptor compensated in large part by oxygen vacancies, resulting in enhanced ionic conduction at low values of x. For larger values (x ≈ 0.05), electronic conductivity predominates which we attribute to electron migration by hopping through a Ru-derived defect band.
A Study of the Electrical Behavior of UO2(O3PC6H5) Supported Film
Authors: Benavente J. , Barrado J.R. Ramos , Bruque S. , Martinez M. 
Published: March 2011

AbstractThe electrochemical behaviour of a polymeric supported uranyl phophonate film, when it is placed in contact with solutions of two generating electrolytes, (H2PO3C6H5 and UO2(NO3)2) at different concentrations, is studied by AC impedance spectroscopy and diffusion potential measurements. The equivalent circuit associated to the film and some of its characteristic electrical parameters (Rf and Qf) are determined. The cation transport numbers in the film (t+ = I+/I) with both electrolytes as well as their variation with concentration are also obtained. Differences found in the Qf parameter for both film/electrolyte systems are attributed to the different values of the transport numbers.
Characterization of I.T.O. Thin Film Electrodes in Li-Based Systems and their Use in Electrochromic Windows
Authors: Golden S. J. , Steele B.C.H. 
Published: March 2011

AbstractThin films of tin-doped indium oxide (I.T.O.) were produced by r.f. sputtering and lithiated electrochemically in LiClO4-PC. X-ray diffraction studies showed a cubic structure with a small increase in the cubic lattice parameter with x up to unity (LixITO). Electrochemical studies indicated that Li insertion is reversible, at least over a small number of cycles. Spectral transmittance decreased slightly with considerable levels of insertion indicating low electrochromic colouration efficiencies and making thin film I.T.O. a suitable counter-electrode material for electrochromic window systems.
Kinetics Study of Hydrogen Discharge from A Lani4.5AL0.5Dy Electrode by in Situ Real Time Neutron Diffraction
Authors: Poinsignon Christiane , Dalphrase Nicole , Latroche Michel , Pannetier Jean , Percheron Annick 
Published: March 2011

AbstractElectrochemical studies performed by linear potential scan voltamperometry on the monosubstituted intermetallic hydrides LaNi4.5M0.5, with M=AI, Mn or Co, confirm previous observations [ 14, 16, 20] of the influence of the nickel substitute on the rate of hydrogen insertion/desinsertion in solid gaz : the rate of discharge is faster for the Co and Mn substituted hydrides than for the Al one : during a controled discharge process by potential step of 20mV during 10 hours, hydrogen full capacity is desinserted over a potential range of 200mV in 80 hours for LaNi4.5AI0.5, over 130mV in 40 hours for LaNi4.5Mn0.5 and over 50mV in 30 hours for LaNi4.5Co0.5Coupled techniques of real time neutron diffraction and linear potential scan voltammetry applied to the in situ study of the charge/discharge of a LaNi4.5A10.5Dx electrode in a KOD 7N electrolyte gives account for the respective variation of the cell parameters of the α and β phases[ 11] and provides access to the hydogen desinsertion kinetics from both phases. The decrease rate of the unit cell volume of the α phase is found to be 4.8 10−3 A3/hour whereas that of the β phase is 61 10−3 A3/hour. At the end of the discharge process occurence of isolated 13ph ase domains is attributed to the faster rate of hydrogen desinsertion in the β phase than in the (β phase, which is in all likelihood at the origin of the loss of capacity observed during cycling for this electrode.
Fourier Transform Infrared (FTIR) Analysis of Copper Oxide Thin Films Prepared by Metal Organic Chemical Vapor Deposition (MOCVD)
Authors: Chang Yu-Neng 
Published: March 2011

AbstractFTIR results from cuprous oxide (Cu2O) and cupric oxide (CuO) films prepared by MOCVDtechnique were presented. According to FTIR and XRD results, Cu2O films can be prepared by MOCVD using 0.20 tort of copper acetylacetonate (Cu(acac)2) vapor and 150 torn of oxygen, at a deposition temperature of 340°C. The strong reductive tendency of Cu(acac)2 vapor in the MOCVD process is noted, as the oxidation state of copper was reduced from 2+ in Cu(acac)2 to 1+ in the Cu2O film. Cu2O films have a strong IR absorption band at 610 cm−1. CuO films were prepared at 0.20 tort of Cu(acac)2 vapor and 190 torr of oxygen, at a deposition temperature of 420°C. The IR bands of CuO films located at 440 cm−1, 480cm−1, and 540cm−1. The XRD results indicated that Cu2O films have a preferential orientation at (111) plane. From IR study, it appears that the MOCVD processing condition has an impact on the film microstructure, which in term influenced the band position and band shape of corresponding IR bands.
The Lithium Electrode Interface: A Crucial Aspect in Polymer Batteries
Authors: Scrosati Bruno , Croce Fausto 
Published: March 2011

AbstractRechargeable, polymer lithium batteries are today considered as very promising advanced power sources for electric vehicle and/or consumer electronics. Many polymer electrolytes, some of which having very high ambient temperature conductivity, have been developed and characterized. However, very little attention has been so far dedicated to the study of the characteristics of the lithium electrode interface. Since the clarification of the interfacial phenomena is crucial in assessing the effective impact of polymer batteries, we have undertaken a detailed investigation of the Li passivation processes in most relevant electrolyte media and in this work we report results obtained in highly conductive cells using electrolytes formed by the immobilization of lithium solvates in polymer networks.
In Situ X-RAY Diffraction Studies of Li+ Insertion into V6O13
Authors: Lampe-Önnerud C. , Gustafsson T. , Thomas J.O. 
Published: March 2011

AbstractA fast in situ X-ray powder diffraction set-up working in transmission mode is used to explore the structural changes occurring on Li+ insertion into the active V6O13 component of the cathode in a thin-film < Li I polymer electrolyte | V6O13 > battery. It is confirmed that the V6O13 is indeed converted reversibly into three discrete phases, LixV6O13 for x = 1, 4 and 8, as the fully charged cell (ca. 3.OV) is discharged to 1.8V. The effect on the insertion process of repeated cycling with different currents has been studied. Cell collapse was induced after ca. 35 cycles for 0.2 mA/cm2. This was not reflected, however, in any significant change in the diffraction pattern from the battery. Moreover, the battery returned to normal functioning after lying on open circuit for 7 days. A gradual loss of reflection intensity is observed, but no particle line-broadening. The implications of these results are discussed as they relate to the nature of the solid-state insertion process of Li+ into V6O13.
Dehydration and Lithium Insertion Studies in Phyllomanganates
Authors: Strobel Pierre 
Published: March 2011

AbstractLayered oxides AxMnO≈2,yH20 (A = Na, K, NH4, Cs or Mn2+) have been dehydrated and intercalated by lithium. Dehydration is accompanied by a shrinking of the interlayer space height depending on the size of A. The valence of Mn is reduced to +2 by reaction with n-butyllithium. Electrochemical studies of cells AxMnO≈2-graphite | LiClO4-PC|I Li showed two main reaction peaks at ca. 3V and below 2 V. The first reaction is a reversible reduction to a disordered Mn3+ phased. Capacities at the third cycle are ca. 300 Wh/kg. No marked difference was found as a function of A or of the degree of order of the starting compound.
Electron Microscopy Characterization Of Epitaxial Growth Of Ag Deposited On Mgo Microcubes
Authors: Liu J. , Pan M. , Spinnler G. E. 
Published: March 2011

AbstractThe crystalline structure, the morphology and the chemistry of small Ag particles vacuum-deposited on preheated MgO microcubes were characterized by in situ and ex situ electron microscopy and surface analysis techniques. Observations were made of the nucleation and growth of Ag clusters on MgO surfaces and along surface steps. It is found that Ag particles deposited onto clean MgO crystals have an epitaxial orientation relationship of (100)Agll(100)MgO with [100]Agll[00]MgO. Prior to air exposure Ag particles are stable under the electron beam but they become unstable upon exposure to air. During electron irradiation on air-exposed samples terraces are formed on the surfaces of MgO cubes, preferentially near Ag particles and at their interfaces with the substrate. The stability of vacuum-deposited Ag particles and the growth of the terraces on MgO microcubes seem to depend on air exposure of the sample.
Artifacts in Atomic Force Microscopy of Nanoporous and Mesoporous Fiducial Samples
Authors: Deckman H. W. , Plano R. J. 
Published: March 2011

AbstractArtifacts dominate atomic force microscope (AFM) images of nanoporous and mesoporous inorganic oxide materials taken under ambient atmospheric conditions with currently available tips. Artifacts in these AFM images are attributed to tip-sample interactions and the sharpness of tips on currently available cantilevers. We show that by modifying currently available AFM tips with carbonaceous materials, many image artifacts are eliminated. To characterize image artifacts, a variety of fiducial samples with feature sizes between ∼100 Å and 2,000 Å are used. One of the most useful fiducial samples is a close packed array of holes in a commercially available alumina membrane and we suggest that it be adopted as a standard fiducial sample.
High Resolution Electron Microscopy of ∑ =3 NiSi2 (111)(115) Si And NiSi2(221)/(001)Si Interfaces
Authors: Chen Wen-Jauh , Chen Fu-Rong 
Published: March 2011

AbstractHigh resolution imaging technique is applied to systematically study the ∑ =3 NiSi2(111)/(115)Si and NiSi2(221)/(001)Si interfaces. The long-period boundaries of ∑ =3 NiSi2 (111)/(115)Si and NiSi2(221)/(001)Si have been shown to decompose into short period of symmetrical NiSi2 (111)/(111)Si and NiSi2 (112)/(112)Si atomic facets which are similar to the case of asymmetrical twin boundaries in NiSi2 crystal. This result is consistent with the computer simulation in grain boundary case that asymmetrical tilt boundaries which are generally of longer periods may facet on an atomic scale into short period symmetrical boundaries.The domain-related atomic faceting interfaces have been found in both of.∑ =3 NiSi2(111)/(115)Si and NiSi2(221)/(001)Si interfaces. The coexistence of two domain-related atomic faceting interfaces in the ∑ =3 NiSi2(111)/(115)Si has also been observed in different area of an interface which are separated by a 1/4<111> type of dislocation associated with a ‘demi-step’. The Burgers vector and step of a dislocation required to separate two domain structures in the ∑ =3 NiSi2/Si interface can be derived from the CCSL model.
Experimental Optimization for Imaging with Photoelectron Diffraction
Authors: Tobin J. G. , Waddill G. D. , Li Hua , Tong S. Y. 
Published: March 2011

AbstractThe experimental apparatus and its optimization for holographic imaging with energy dependent photoelectron diffraction are described. A substantial improvement in data taking efficiency has resulted, allowing total data collection time to be reduced to about twelve hours for a single image-map.
Design of Ultra High Vacuum Scanning Electron Microscope Combined with Scanning Tunneling Microscope
Authors: Takai Mikio , Yokoi Naoki , Mimura Ryou , Sawaragi Hiroshi , Aihara Ryuso 
Published: March 2011

AbstractAn ultra high vacuum (UHV) scanning electron microscope (SEM) combined with a scanning tunneling microscope (STM) has been designed and constructed to solve problems, arising from STM surface imaging and nanofabrication using STM tips, such as difficulty in probe tip location and change in tip shape. The system facilitates to image and/or to modify a wide range of area from submicron down to subnanometer. A ZrO/W thermal emitter in a Schottky mode has been used for an electron gun to obtain a low energy spread with a high angular current density. Minimum beam spot diameters of 6 and 12 nm with currents of 100 pA and 4 nA are estimated by optical property calculation for high resolution (SEM) and high current (fabrication) modes, respectively.
The Surface Structure of Oxides Studied with Reflected High Energy Electrons
Authors: Hsu Tung 
Published: March 2011

AbstractReflected high energy electrons have been employed for studying surfaces of single crystal oxides in real and reciprocal space. The techniques used include reflection high energy electron diffraction (RHEED), reflection electron microscopy (REM), scanning reflection electron microscopy (SREM), and reflection electron energy loss spectroscopy (REELS). These methods have provided much information on surface morphology as well as the atomic and electronic structure of MgO, ∝-Al2O3, ∝ -Fe2O3, SiO2, TiO2(rutile), and ZnO single crystals. Analyses for chemical composition and electronic states are possible using SREM and REELS. Surfaces terminating at different atomic layers of large-unit-cell materials have been determined in REM images and also in REELS data obtained under REM and SREM. Surface modification due to bombardment with the incident electron beam is pronounced on some oxide surfaces. These processes have been investigated with the REM imaging and REELS techniques.
Scanning Tunneling Microscopy Perspective of Structures on Reduced SrTiO3 (001) Surfaces
Authors: Liang Yong , Bonnell Dawn A. 
Published: March 2011

AbstractScanning tunneling microscopy has been used in ultra high vacuum to provide atomic scale structural information on reduced SrTiO3(001) surfaces. Our tunneling images exhibit row-like features with 12 Å and 20 Å periodicities on the reduced surface. A local 2×1 reconstruction was also revealed on some regions of the surface. The experimental results are discussed in terms of the different sublimation rates of surface constituents and formation of lamella structures of Srn+lTinO3n+l.
Surface Structure and Electronic Property of Reduced SrTiO3 (100) Surface Observed by STM/STS
Authors: Matsumoto Takuya , Tanaka Hiroyuki , Kawai Tomoji , Kawai Shichio 
Published: March 2011

AbstractWe have obtained STM images and STS data with atomic-scale resolution for SrTIO3 (100) surface annealed in UHV at 1200 °C. A √5×√5-R26.6° surface superstructure indicating oxygen vacancy ordering has been observed. The STS data provide evidence for a localized surface state arising from oxygen vacancies at 1.35 eV below the Fermi level. STM images of the √5×√5 structure correspond to the surface orbital of the ordered Ti-oxygen vacancy.
Mechanisms and Energetics of Surface Atomic Processes, an Atom-Probe Field Ion Microscope Study
Authors: Tsong Tien T. 
Published: March 2011

AbstractAtom-probe field ion microscopy is capable of imaging solid surfaces with atomic resolution, and at the same time chemically analyzing atoms selected by the observer from the atomic image. The samples are restricted to those having a tip shape, but in many cases this is no longer a drawback since structures in high-tech materials are reducing in size to that comparable to or smaller than the field ion emitter tip. This technique is finding many applications in different areas. Our recent applications of this technique to the study of the dynamical behavior of surfaces and surface atoms and their mechanisms and energetics, and the atomic scale chemical and composition analysis will be briefly described.
Growth and Surface Morphology of Thin Silicon Films Using an atomic Force Microscope
Authors: Hegde Rama I. , Chonko Mark A. , Tobin Philip J. 
Published: March 2011

AbstractThe growth and surface morphology of thin LPCVD silicon films were investigated with an atomic force microscope (AFM). Silicon films of 30 nm thicknesses were deposited on SiO2 using SiH4 at four different temperatures between 550 °C and 625 °C. These AFM results permitted visualization of silicon surface granularity, roughness, and the transition with temperature from amorphous to crystalline structure between 550 °C and 580 °C. The surface of the amorphous film deposited at 550 °C is very smooth and the film is continuous physically, while the film formed at 580 °C appears crystalline, rough and porous. At 600 °C and 625 °C the films are fully crystalline. For these higher temperature films surface roughness and the average grain size decreased significantly compared to 580 °C film. Crystallinity and film continuity were further examined by x-ray diffraction (XRD) and cross-sectional TEM measurements.