bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surface Characterization of Carbon-Bearing Magnetite (CBM) and Carbon-Bearing Ni(II)-Ferrite (CBNF)
Authors: Sano T. , Akanuma K. , Tsuji M. , Tamaura Y. 
Published: April 2011

AbstractOxygen-deficient magnetite (ODM; Fe3O4-δ, δ>0) synthesized by reduction of magnetite with H2 at 300°C decomposed CO2 to carbon with an efficiency of nearly 100% at 300°C. In this reaction, two oxygen ions of the CO2 were incorporated into the spinel structure of ODM and carbon was deposited on the surface of ODM with zero valence to form visible particles. The particles of carbon separated from ODM were studied by Raman, energy-dispersive X-ray and wave-dispersive X-ray spectroscopies. The carbon which had been deposited on the ODM was found to be a mixture of graphite and amorphous carbon in at least two levels of crystallization. X-ray photoelectron spectroscopy and X-ray diffraction patterns of the carbon-bearing magnetite (CBM) showed no indication of carbide (Fe3C) or metallic iron (α-Fe) phase formation. In the C 1s XPS spectra of the CBM, no peaks were observed which could be assigned to CO2 or CO. X-ray diffractometry, chemical analysis and TG-MS measurement showed that the carbon-bearing Ni(II)-ferrite (CBNF) (Ni(II)/Fetotal = 0.15) synthesized by the carbon deposition reaction from CO2 with the H2-reduced Ni(II)-ferrite was represented by (Ni0.28Fe2.72O4.00)1-δ (Ni2+06.9Fe2+2.31O3.00)δCτ (δ= 0.27, τ= 0.17). The carbon of the CBNF gave the CIOlayer-like oxide containing some Ni2+ ions.
Recycled Rubber in Cement Composites
Authors: Raghavan D. , Tratt K. , Wool R. P. 
Published: April 2011

AbstractDisposal of 200 million waste tires in the US each year has become a major problem. An environmentally sound innovative technology of recycling rubber in cement matrix was examined. Using silane coupling agent the rubber was bonded to the hydrating cement making a lighter composite, which absorbed more energy than ordinary Portland cement. The bonding information was obtained by peel strength analysis. SEM was used to understand the mode of fracture in pure cement paste, cement bonded rubber composite and rubber filled cement paste. It was found that cracks propagate through the rubber particle in rubber bonded cement composite while in unbonded rubber cement mix, the cracks propagate around the interface. The density and shrinkage measurements are also discussed.
Recycling of Plastic and Rubber Tire Waste in Asphalt Pavements
Authors: Morrison Geoffrey R. , Lee Nolan K. , Hesp Simon A.M. 
Published: April 2011

AbstractThis paper discusses some important issues related to the use of recycled thermoplastics and rubber tire waste in asphalt binders for hot-mix pavements. Both high temperature rheological and low temperature fracture studies are presented on recycled polyethylene, devulcanized and crumb rubber-modified asphalt binders. The results are compared to unmodified and commercially available modified binders. This research is especially timely in light of the U.S. Intermodal Surface Transportation Efficiency Act of 1991, Section 1038 which, starting in 1995, will force state and local governments to use significant amounts of recycled rubber tire or plastic waste in federally funded highway projects.High temperature rheological measurements of the loss modulus, loss tangent and complex modulus show a significant improvement when only small quantities of crumb rubber, devulcanized crumb rubber or waste polyethylene are added to the asphalt binders.The low temperature fracture performance of the modified asphalts is greatly influenced by the interfacial strength between the dispersed and continuous phase. The fracture toughness increases dramatically, only when low molecular weight polymers are grafted in-situ onto the rubber and polymer dispersed phases in order to strengthen the interface. This points to a crack-pinning mechanism as being responsible for the dramatic increase in fracture toughness that is observed in this work. Single phase, devulcanized crumb rubber-asphalt systems perform quite poorly at low temperatures.
Fundamentals of Particle Flocculation and Removal From Water
Authors: Spicer Patrick T. , Pratsinis Sotiris E. 
Published: April 2011

AbstractThe flocculation of polystyrene particles with aluminum sulfate or alum (Al2 (SO4)3) by turbulent shear was studied as a function of the applied shear rates (63–129 s−1) and flocculant concentrations (11 and 32 mg/L) in a stirred tank. Increasing the shear rate increased the floc growth rate but decreased the maximum attainable floc size. Increasing the concentration of alum increased the floc growth rate and the maximum floc size. A steady state between floc growth and breakage was attained after which the floc size distribution no longer changed. The normalized steady state size distributions allowed evaluation of the relative contributions of shear rate and flocculant concentration to the performance of the process.
Structural Development In Silica Systems
Authors: Dokter W.H. , Beden T.P.M. , van Garderen H.F. , van Santen R.A. 
Published: April 2011

ABSTRACTResults obtained with small angle neutron and X-ray scattering will be
presented of systems with various silica concentrations. Silica gels with
low silica concentration exhibit uniform mass fractal behaviour and after
prolonged aging, dual mass fractal behaviour. A zeolite (silicalite)
synthesis precursor gel with a high silica concentration was also
investigated and was found to exhibit surface fractal behaviour. A model is
presented, explaining the occurrence of dual fractality after prolonged
aging. The change-over from mass fractal behaviour to surface fractal
behaviour is explained, supported by scattering spectra calculated from
simulated aggregate structures.
Formation, Structure, and Material Properties From the Reaction
Product of M(OCHMe2)4 (M=Ti, Zr) And
HOAc
Authors: Alam Todd M. , Boyle Timothy J. , Buchheit Catherine D. , Schwartz Robert W. , Ziller Joseph W. 
Published: April 2011

ABSTRACTIn attempt to ultimately control the characteristics of the PZT films, we
have decided to investigate some of the basic chemistry associated with
these solutions. Frequently, these solutions have been generated from Group
IV metal alkoxides in acetic acid (HOAc). Therefore, studies of the
simple reactivity between
M(OCHMe2)4 (M = Ti, Zr) and HOAc have been
undertaken. These reactions were monitored by 1H, 13C,
17O NMR, FT-IR, TGA/DTA, and single crystal X‐ray studies.
Films were produced from spin‐coat deposition of crystalline material (from
the titanium reaction) in toluene and aged solutions as well.
Titania-Alumina Composites
Authors: Luo Shengcheng , Gui Unli'n , Fu Xianzhi , Tang Youqi 
Published: April 2011

ABSTRACTTitania-alumina composites were carried out by various methods. The
composite prepared by mixed gelation method showed the merits of both
γ-Al2O3 and TiO2 (anatase), and it
behaved much better than the γ-Al2O3 alone as the
carrier of HDS catalyst or H2S adsorbent. Another representative composite
was prepared by sol-gel method. The hydroxide of aluminium alkoxide was
peptised directly with TiCl4 to form
TiO2-Al2O3 composite sol, and then the
composite membrane without support was obtained. The sizes of primary
particles were around 5nm as characterised by TEM.
Nano-Crystalline Powders and Suspensions Generated Using A
Flow-Through Hydrothermal Process, Part II: Applications
Authors: Darab John G. , Buehler M. F. , Linehan J. C. , Matson D. W. 
Published: April 2011

ABSTRACTUltra-fine, nano-crystalline six-line ferrihydrite
(5Fe2O3-9H2O) and cubic zirconia (ZrÜ2)
powders have been produced using the Rapid Thermal Decomposition of
precursors in Solution (RTDS) technology. Nano-crystalline RTDS six-line
ferrihydrite powder used as an in situ precursor for
first-stage direct coal liquefaction catalysts increased the liquefied
products from Blind Canyon Seam coal by 22% absolute over thermal background
at 350°C. Initial sintering studies performed on nano-crystalline RTDS
ZrO2 powder have also been presented and compared to
predictions made from theories derived for micro-crystalline powders.
Engineering of Porosity in Amorphous Materials. Plasma Oxidation
of Hydrocarbon Templates in Polysilsesquioxanes*
Authors: Loy Douglas A. , Buss Richard J. , Assink Roger A. , Shea Kenneth J. , Oviatt Henry 
Published: April 2011

ABSTRACTArylene- and alkylene-bridged polysilsesquioxanes were prepared by sol-gel
processing of bis(triethoxysilyl)-arylene monomers 1-4, and alkylene
monomers 5-9. The arylene polysilsesquioxanes were porous materials with
surface areas as high as 830 m2/g (BET). Treatment with an
inductively coupled oxygen plasma resulted in the near quantitative removal
of the arylene bridging groups and a coarsening of the pore structure. Solid
state 29Si NMR was used to confirm the conversion of the
sesquioxane silicons (T) to silica (Q). The alkylene-bridged
polysilsesquioxanes were non-porous. Oxygen plasma treatment afforded silica
gels with mesoporosity. The porosity in the silica gels appears to arise
entirely from the oxidation of the alkylene spacers.
The Reactivity of C60 in Fuming Sulfuric and Chlorosulfonic Acids
Authors: Miller G.P. , Buretea M.A. , Swirczewski J.W. , McConnachie J.M. 
Published: April 2011

ABSTRACTC60 is sultonated in fuming sulfuric acid and chlorinated in chlorosulfonic acid. Both reactions involve initial oxidation of C60 followed by in situ trapping of electrophilic C60 cation.
Fi-Stm Study of Fullerenes
Authors: Hashizume Tomihiro , Sakurai T. 
Published: April 2011

ABSTRACTAdsorption of C60, C70, C60(x)C70(1-x) and Sc2C84 on the Cu(111)1×1 and Ag(l11)1×1 surfaces has been investigated by field ion-scanning tunneling microscopy (FI-STM). On the Cu(111) and Ag(111) surfaces, the fullerene molecules are mobile on the terrace at room temperature and segregate to the steps to form linear chains then two-dimensional islands with a close-packed configuration. Upon monolayer adsorption, highly ordered 4×4 commensurate phases form in the case of the C60, C70 and C60(x)C70(1−x) adsorption on the Cu(111) surface, while close-packed hexagonal multiple phases, with nearest-neighbour distance equal to that of the bulk phase, form in the case of the C60 and Sc2C84 adsorption on the Ag(111) surface. These observations imply the competition between the adsorbate-adsorbate and adsorbate-substrate interactions. The intramolecular structures observed in the STM images of the C60 and C70 molecules in the Cu(111)-4×4 phases are analyzed to determine the adsorption geometry and are interpreted as the local density of the states of the C60 and C70 molecules.
Electrical Properties of C60 and Its Partially Decomposed Thin Films Fabricated by Vacuum Evaporation and Ion Plating Methods
Authors: Asakawa T. , Sasaki M. , Yoshimoto M. , Gonda S. , Shiraishi T. , Koinuma H. 
Published: April 2011

ABSTRACTThin films were prepared, from C60 powders by vacuum evaporation and rf-plasma excited ion plating methods. The film structures ranged from fcc-polycrystal C60film to amorphous C60 film and to amorphous carbon films containing varying amounts of C60 molecules depending on the preparation method and conditions. Electrical conductivity of these films was found so sensitive to air that highly reproducible data were obtained only when the measurement was done by in-situ high vacuum conditions. The Co films deposited at 120°C on fused silica substrates by vacuum evaporation were amorphous and they had conductivities three orders of magnitude lower than those of fcc-polycrystal C60 films deposited on cleaved NaCl(100) substrates under the same conditions. The conductivities of both amorphous and fcc-polycrystal C60 films decreased drastically when these films were exposed to air. Partially decomposed C60 ion-plating films showed conductivities close to those of the air-exposed amorphous and fcc-polycrystal C60 films.
Crystal Structure of Endohedral Metallofullerene La@C82
Authors: Suematsu H. , Murakami Y. , Kawata H. , Fujii Y. , Hamaya N. , Shimomura O. , Kikuchi K. , Achiba Y. , Ikemoto I. 
Published: April 2011

ABSTRACTSince the success of synthesis the molecular structure of the endohedral metallofullerene is a most interesting subject in relation to the electronic state of metal and carbon cage. Highquality crystals of endohedral metallofullerene La@C82 have been synthesized by the arc discharge and HPLC method. The x-ray powder diffraction and the precession photograph of a tiny single crystal have revealed the cubic structure with the space group I43d and the lattice constant ao = 25.72 ± 0.007 Å at room temperature. The structure is characterized by the molecular arrangement in which the molecules align in the [111] direction with the molecular axis orienting in the same [111] direction; this structure suggests the existence of a dipole interaction between the molecules. The metal position in the cage is also discussed on the basis of an ellipsoidal model of molecule.
Controlled Formation of Buried Layers of Carbon
Authors: Ila D. , Zimmerman R. L. , Jenkins G. M. 
Published: April 2011

ABSTRACTPartially cured and cured PF-resin samples were prepared at 150°C, 170°C and at 200°C in an inert environment and then bombarded by MeV ion beams using protons, alphas and nitrogen. Using low ion beam current density, 100 to 500 pA/mm2 for the nitrogen ions, 10 to 20 nA/mm2 for the alpha ions, and 50 to 500 nA/mm2 for protons, we have produced buried carbon layers without breakdown i.e., crack formation. The thicknesses of the carbon layers produced were of the order of a few tens of nanometers at a depth of a few nanometers to several micrometers depending on the energy, the type of bombarding ions and the curing temperature of the precursor. The electrical resistivity of these layers was measured in situ and was reduced from 109 Ω-cm to 10 Ω-cm. The lowest resistivity, 10 Ω-cm, was measured in the alpha bombarded, 150°C heat-treated resin. The carbonized volumes were analyzed by Raman microprobe spectroscopy which showed that the strongest graphitic (G-line) and distorted (D-line) Raman signals observed were from the nitrogen and alpha irradiated samples.
Photocarrier Generation in Fullerene Films
Authors: KÖnenkamp R. , Erxmeyer J. , Weidinger A. 
Published: April 2011

ABSTRACTWe present results from a detailed study of photoconductivity in thin C60 films. It is shown that the generation of mobile charge carriers involves molecular electronic transitions coupled to molecular vibrations. The vibrational bands broaden with temperature and shift at the fcc-to-scphase transition. For excitations with energy below ∼1.8 eV photoconduction appears to involve a tail of defect states whose distribution is somewhat dependent on sample preparation.
Nucleation and Growth Processes During The Chemical Vapor Deposition of Diamond
Authors: Angus John C. , Evans Edward A. 
Published: April 2011

ABSTRACTThe nucleation of independent diamond crystals can occur through graphitic, sp2, intermediates. Evidence from several sources indicates that diamond growth may take place through sp2 surface layers. Steady state analysis of simple reaction networks leads to expressions for the diamond growth rates, the concentration of sp2 impurities in the diamond, and for the nucleation rate of new crystals.
A Comparative Study of Nucleation Enhancement Techniques for Plasma Cvd of Diamond Thin Films
Authors: Meilunas R.J. , Tobin A. 
Published: April 2011

ABSTRACTThree methods recently proposed for enhancing the nucleation density of thin film diamond on non-diamond surfaces during microwave plasma assisted chemical vapor deposition are investigated. The results of a series of nucleation and growth studies utilizing a dc biasing technique, carbon cluster (C70) thin film overlayers, and thin film metal (Fe) overlayers for diamond nucleation enhancement are presented. The influence of the substrate and plasma processing parameters under which the above nucleation enhancement effects occur has been determined for the three respective techniques.
Preparation of High Density Graphite Materials from Coal Tar Pitch
Authors: Park Yang-Duk , Kim Chul-Woo , Seo Young-Dae 
Published: April 2011

ABSTRACTPreparation of high density graphite materials from coal tar pitch was investigated. The effect of β-resin content on the mechanical properties of graphite solid prepared from semi-coke, which was prepared by wet milling method, was examined. β-Resin content was effective for fabrication of green bodies without lamination and for improving the mechanical properties of graphite materials.
Parameter Optimization for the Arc-Adlc-Deposition Process
Authors: Knotek O. , Löffler F. , Barimani C. , Brand J. 
Published: April 2011

ABSTRACTOne method used by the industry for the deposition of thin carbon films is the dc cathodic arcion plating process. The evaporation of a graphite cathode by a high energy arc beam results in the production of carbon atoms, ions and macroscopic graphitic fragments. All these particles influence the film growth, the structure and therefore the film properties. The incorporation of the macroscopic graphitic fragments can be avoided by the use of mechanical or magnetic filters in front of the cathode. These filters prevent the direct bombardment of the substrates with particles. This particle separation involves decreased substrate current densities and this means lower deposition temperature (< 200°C) and growth rates. With the addition of inert (argon) and reactive gases (nitrogen and methane) and the use of a bias voltage on the substrate economical deposition rates of 2-4 μm/h and good adhesion on various materials can be reached.This paper describes the production of amorphous hydrogen and hydrogen-free carbon films by a modified cathodic arc evaporation process using a simple mechanical filter for particle reduction. It shows the influence of some process parameters on the optimization of the process stability and process efficiency. Some characteristic properties of these coatings are shown by an example.
Atomic Structure Modifications of Diamond-Like Nanocomposite Films: Observation by Raman Spectroscopy, FTIR and STM
Authors: Dorfman B. , Abraizov M. , Pollak Fred H. , Yan D. , Strongin M. , Yang X.-Q. , Rong Z.-Y. 
Published: April 2011

ABSTRACTRaman spectroscopy, FTIR and scanning tunneling microscopy (STM) were used to study diamond-like nanocomposite (DLN) and metal containing DLN (Me-DLN) films. The FTIR spectra showed no appreciable absorption from the C-H stretch vibration band in DLN when 1 kV rf bias voltage was applied. Thermal annealing (450°C for 2 hrs) of (a) DLN and Cr-DLN films caused no change in the Raman spectra while (b) for Pt-DLN films there was a blue shift of both the crystalline (G) and microcrystalline (D) graphite-like features, an increase in the ID/IG intensity ratio and a decrease in the linewidths. The changes observed were more pronounced in the film with the highest Pt concentration. The STM image of this Pt-DLN film revealed a structure of aromatic graphite rings.
Preparation and Characterization of Aerogel-Based Carbon Nanocomposites
Authors: Cao Wanqing , Song Xian Yun , Hunt Arlon J. 
Published: April 2011

ABSTRACTAerogels are highly porous solids prepared by sol-gel processing and supercritical evacuation. Because of their high surface area, aerogels can be used as an effective catalyst for the thermal decomposition of many gaseous compounds. A variety of hydrocarbon gases have been chosen to deposit carbon in the aerogel matrix, with the deposition temperature varying from 500° to 850°C depending on the hydrocarbon used. The amount of carbon that can be deposited in the aerogel is surprisingly large, reaching up to 10 times the original weight after extensive deposition using acetylene. Overall, the aerogel composites prepared have a uniform microstructure with the average particle size in the nanometer range. In addition, we have observed some interesting graphitic structures including carbon nanotubes and rings of various shapes. Carbon deposited in the aerogel can reduce infrared transmission of the material as well as volume shrinkage at elevated temperatures, thereby improving its thermal performance.
Computer Simulation of Creation and Motion of Edge Dislocations in Face Centered Crystals
Authors: Tajima N. , Nozaki T. , Hirade T. , Kogure Y. , Doyama Masao 
Published: April 2011

AbstractComplete and dissociated edge dislocations were created near the center of the surface (101) of aluminum small crystals whose surfaces are (111), (111), (101), (101). (121) and (121). Molecular dynamics with N-body embedded atom potentials were used. Higher stress is needed to create a complete edge dislocation than to create a dissociated dislocation.
Stress Evolution During the Formation and Transformation of Titanium Silicide
Authors: Svilan V. , Harper J. M. E. , Cahral C. , Clevengeri L. A. 
Published: April 2011

AbstractThe evolution of stress vs. temperature was measured during the formation of TiSi2 in the reaction of Ti with (100) Si and with polycrystalline Si, and during the phase transformation from C49 to C54 TiSi2. The formation of C49 TiSi2 causes an increase in compressive stress, followed by relaxation before the transformation to C54 TiSi2, which causes no significant stress change. C54 TiSi2 is shown to be elastic in the temperature range of 750–860 °C. This difference in the deformation mechanisms of C49 and C54 TiSi2 affects the morphological stability of TiSi2 in fine line structures.
Growth of Hydrogenated Amorphous Silicon (A-Si:H) on Patterned Substrates for Increased Mechanical Stability
Authors: Hong Wan-Shick , Delgado J. C. , Ruiz O. , Perez-Mendez V. 
Published: April 2011

AbstractResidual stress in hydrogenated amorphous silicon (a-Si:H) film has been studied. Deposition on square island pattern reduced the stress when the lateral dimension of the islands became comparable to the film thickness. The overall stress was reduced by approximately 40% when the lateral dimension was decreased to 40 μm, but the adhesion was not improved much. However, substrates having a 2-dimensional array of inversed pyramids of 200 μm in lateral dimension produced overall stress 3∼4 times lower than that on the normal substrates. The inversed pyramid structure also had other advantages including minimized delamination and increased effective thickness. Computer simulation confirmed that the overall stress can be reduced by deposition on the pyramidal structure.
X-Ray Measurements of Deformations in Films and Substrates in Heteroepitaxial SYSTEM GaAs/Ge
Authors: Burle N. , Pichaud B. , Thomas O. 
Published: April 2011

AbstractX-Ray Transmission and Reflection Topography settings have been used to perform stress and strain measurements in the epitaxial system GaAs/Ge : radius of curvature of the whole sample is obtained from the Lang (transmission) set-up ; tetragonal distortion in the layer is deduced from the Berg-Barrett (reflection) setup. Comparison of these results and correlation with dislocations densities estimated from topographs enable the elastic state of the system to be known.
Mechanical Properties and Microstructure of AL(1wt%SI) And AL(1wt%SI, 0.5wt%CU) Thin Films. The Role of Diffusional Creep in the Tensile Stress Regime
Authors: Bader S. , Kalaugher E. M. , Arzt E. 
Published: April 2011

AbstractThe microstructure and mechanical properties of hot (h) and cold (c) sputtered Al-lwt%Si and Al-lwt%Si-0.5wt%Cu films were studied using transmission electron microscopy and wafer curvature stress measurements.Stress/temperature curves of all films showed only slight differences in compression on healing once a stable grain size was established. However, on cooling several remarkable differences were observed. These observations cannot be explained by assuming dislocation glide/climb as the dominant relaxation mechanism. The results will be discussed in terms of grain boundary diffusional relaxation (Coble creep), which occurs in addition to dislocation glide.