bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Drying on Viscoelasticity and Permeability of
Gel
Authors: Scherer George W. 
Published: April 2011

ABSTRACTThe beam-bending method was used to measure the effect of partial drying on
the viscoelastic relaxation behavior and permeability of a two-step
acid-base catalyzed silica gel. Both the elastic modulus
(E) and the permeability (D) showed a
power-law dependence on density (ρ): E ～
ρm, m ≈ 3.0; D ～
ρ-n, n ≈ 2.5. The viscosity of the network rose
from ～1011 to ～1013 Pa·s, and was strongly dependent
on age as well as density of the gel. The viscoelastic relaxation function
was well described by the stretched exponential function with an exponent of
0.3–0.5.
Controlling the Properties of Bulk Metal Oxides at a Molecular
Level: Alkoxides Vs Carboxylates‐Alkoxides Routes
Authors: Hubert‐pfalzgraf Liliane G. , Daniele Stephane , Boulmaaz Souad , Papiernik Renee 
Published: April 2011

ABSTRACTThe reactions between alkoxides and/or alkoxides and anhydrous acetates have
been investigated for access to advanced multicomponent niobates or
titanates and with the aim to get insight into relationships between the
nature of the initial precursors ‐ single or mixed‐metal derivatives,
ligands (OAc or OR, R = Et, iPr),…‐ and the properties of the final
material. Data are based on a variety of techniques: FT‐IR, multinuclear NMR
(1H, 13C, 207Pb, 113Cd),
X‐ray investigations on single crystals. Powders have been analyzed by TGA,
SEM‐EDX, light scattering and XRD.
Tga and Dta Studies of Solvent-Exchanged Gels
Authors: Leeb Kurt , Durakpasa Hildrun , Breiter Manfred W. 
Published: April 2011

ABSTRACTSols were prepared in the system TMOS:H2O:SOLV:HC1 with molar
ratios of 1:4:3:0.0005 for SOLV = MeOH, EtOH and DMF. The gelation and aging
of these sols took place in cuvettes covered by parafilm. The gels were
removed from the cuvettes 14 days after gelation. Solvent exchange was
carried out in each of the three solvents for a period of 14 days. Starting
with fresh solvent, the exchange was repeated three times.TGA and DTA curves were taken with pieces of the original gels and of gels
after the 2nd and 3rd solvent exchange. The TGA curves display a
considerable weight loss in the temperature range of solvent evaporation. A
small step is observed at higher temperatures if MeOH or EtOH represent the
exchange solvent. The DTA curves allow a distinction what mixtures of
solvents are present. The effectiveness of the solvent exchange can be
evaluated.
Effects of Rare Earth Incorporation on the Ferroelectric and
Dielectric Properties of Sol-Gel Derived PbTiO3
Films
Authors: Teowee G. , Baertlein C.D. , Schlegel S.A. , Boulton J.M. , Uhlmann D.R. 
Published: April 2011

ABSTRACTFerroelectric (FE) films, especially PZT films, have received increasing
attention for microelectronics applications such as FE memory and in high
density DRAM's. While rare earth doped PbTiO3 ceramics has been
studied for SAW and piezoelectric applications, rare earth-doped films
seldom have been systematically explored. A series of sol-gel derived
PbTiO3 films with varying amounts (5-15 mole %) of rare earths
(such as, Nd, Sm, Tb, Dy, Er ,Yb and La ) have been prepared using acetates
and alkoxides as precursors. The solutions were spin coated onto platinized
Si wafers. The effects of the type and amount of rare incorporation on the
phase assembly and microstructure have been quantified. The results of
dielectric characterization (e.g., dielectric constant, dissipation factor
and leakage currents) and FE behaviors (viz remanent polarization, and
coercive field) are presented; these films exhibited low leakage currents
(3E-10 A/cm2) and much higher dielectric constant (up to 525)
compared to undoped PbTiO3 films.
Preparation of Ceramic Composites by
Active-Ftller-Controlled-Polymer-Pyrolysis
Authors: Colombo Paolo , Abdirashid Mohamed O. , Guglielmi Massimo , Esposti Luca Mancinelli Degli , Agostini Luca 
Published: April 2011

ABSTRACTActive-filler-controlled-polymer-pyrolysis has recently been reported as a
novel processing route for preparing near-net shape bulk ceramic composite
materials. Active fillers, like Ti or Si powders, may react with solid or
gaseous decomposition products of the polymer or with the heating gas
atmosphere. In this study, a mixture of silicone resin (GE SR350) and Si
powder was heated at temperatures up to 1430°C in Ar or N2. After
the highest temperature firing, the resulting material was primarily
comprised of SiC and SiOC when the heating was performed in Ar, or of SiOC,
SiC, Si3N4 and Si2N2O when the
heating was performed in N2. The evolution of the microstructure
of the ceramic composite was followed by DTA-TGA, FT-IR and XRD.
The Incorporation and Thermal Stability of Organic Dyes in
Dialkylsiloxane-Oxide Matrices
Authors: Darabi John G. , Schmidt W. R. , Schwenke G. , MacCrone R. K. 
Published: April 2011

ABSTRACTThe dyes oxazine 725, 7-acetoxy-4-methyl coumarin,
O-4-methylcoumarinyl-N-[3-(triethoxysilyl)-propyl] carbamate and
2′,7′-dichlorofluorescein were introduced during the acid-catalyzed
cohydrolysis of various molar ratios of tetraethoxysilane (TEOS) and the gel
modifers, diethoxydimethylsilane (DEDMS) or diethoxymethylvinylsilane
(DEMVS). The morphological features and optical absorption spectra of the
resulting dye doped gels were followed during subsequent drying and heating.
For DEDMS-TEOS molar ratios less than 1.375, gel cracking during drying was
a problem. DEDMS-TEOS molar ratios greater than 2.750 yielded optically
transparent monoliths, but did not allow for sufficient incorporation of dye
to be useful. However, the functionalized dye,
0-4-methylcoumarinyl-N-[3-(triethoxysilyl)-propyl] carbamate, appeared to be
significantly more soluble in such a highly modified matrix. Compared to
matrices derived from pure TEOS the DEDMS or DEMVS modified matrices
provided oxazine 725 doped with improved thermal stabilities. Finally, the
2′,7′-dichlorofluorescein doped dimethylsiloxane-oxide matrix showed good
thermal stability in its optical properties, having significant optical
absorption and little change in the wavelength of the absorption maximum
after heating to 300°C.
Microstructure and Crystallization Behavior of Sol-Gel Prepared
BaTiO3 Thin Films
Authors: Gust M.C. , Momoda L.A. , Mecartney M.L. 
Published: April 2011

ABSTRACTThin films of BaTiO3 were prepared by the sol-gel route using
barium titanium methoxypropoxide in methoxypropanol. Sols with water of
hydrolysis varying between h=0 and h=2 were spun onto (100) Si and Ge coated
(100) Si substrates. XRD and analytical TEM were used to study the
microstructure and crystallization behavior of these films. Polycrystalline
BaTiO3 was obtained by heat treating the films at temperatures
between 600 and 750°C using either conventional furnace annealing or rapid
thermal annealing. Films prepared from sols having the highest water content
tended to crystallize first. The BaTiO3 thin films exhibited a
fine grain size on the order of 25–50 nm. No preferred orientation was
observed. The effects of the hydrolysis conditions of the sol, the type of
heat treatment, and the choice of substrate on the final microstructure of
the films are discussed.
Electron Microscope Study of Revolving Crystal Growth of Ý–Type
Vanadium Oxide Hydrate Under Hydrothermal Conditions
Authors: Kittaka S. , Miyahara H. , Yokota Y. 
Published: April 2011

ABSTRACTAnomalous revolving stacking crystal growth of β-type vanadium oxide hydrate
formed by hydrothermal treatment was studied by transmission electron
microscopy.
Retention Behaviours Of Carbon In Sol-Gel Derived
ZrO2 Studied By Fourier Transform Infrared
Spectroscopy
Authors: Zeng H.C. 
Published: April 2011

ABSTRACTThe carbon retention patterns based on evolution of FT-IR spectra at
different calcination temperatures for ZrO2 gels derived from
Zr-n-propoxide-acetylacetone-water-isopropanol system are examined in
detail. For most captured carbon species, carbon can be depleted at
relatively low temperature of about 400°C. However, for lattice-included
species, especially those incorporated into lattice during phase transition,
a temperature around 900°C is needed to eliminate carbon in the gels. It is
found that water treatment alone does not provide new routes for carbon
retention in as-prepared ZrO2 gels. When gels are pre-treated
with Ni2+ and water, new forms of carbon containing species can
be observed. This is attributed to an inter-diffusion of Ni2+ and
ZrO2 matrix and the catalytic effect of resultant solid
solution NiO-ZrO2 on the retained carbon.
Rare-Earth Doped, Low Hydroxyl Organically Modified
Silicates
Authors: Yuh Soon-ku , Bescher Eric P. , Babonneau Florence , Mackenzie John D. 
Published: April 2011

ABSTRACTLow-hydroxyl organically modified silicates (ORMOSILS) were fabricated by a
non-hydrolytic reaction between methyl-modified silicon halides and tertiary
butyl alcohol under controlled atmosphere. The gels were characterized by
DTA and TGA., FTIR, 1H NMR and 29Si NMR. The solutions
were doped with anhydrous Erl3, which was dissolved in the sol
prior to gelation. Er3+luminescence in the gels was observed at
570 nm under excitation at 488 nm.
Nanoporosity in Ceramics from Polymeric
Precursors
Authors: Reid A.W. , Rand B. , Emsley R.J.P. 
Published: April 2011

ABSTRACTIt is shown that ceramics derived from polycarbosilane polymers may develop
an open nanoporous network after heat treatment to a temperatures between
1300 and 1550°C in argon. The resulting SiC-based ceramics were
characterised by N2 gas adsorption analysis and X-ray
diffraction. The apparent surface area, and pore volume increase with
increasing heat treatment temperature, reaching values of 170
m2g-1 and 0.12 cm3-1 respectively. The
pore network develops as the SiC crystals grow and as carbon is ejected from
the structure. It is thought that the porosity may reside within the carbon
phase, but this remains to be confirmed.
Mobility Range in Hybrid Materials
Authors: Judeinstein P. , Brik M. E. , Bayle J. P. , Courtieu J. , Rault J. 
Published: April 2011

ABSTRACTThe dynamical properties of hybrid materials obtained from mixtures of
silicon alkoxides and polyethers are studied. Different techniques are used
to analyze the mobility of the different parts of the material: thermal
analysis (DSC, DTMA) and NMR to probe the collective motion modes and EPR to
probe the local scale. The motions are dependent on the organic ratio in the
blend and the covalent grafting between the two phases. Some structural
models of these blends are proposed.
Relationships Between the Structure and the Surface Activity of
Nano-Sized Alumina in Acid Catalysis
Authors: Coster D. , Gruver V. , Blumenfeld A. , Fripiat J. J. 
Published: April 2011

ABSTRACTAs shown in another communication to Symposium V, nano-sized aluminas
enriched in pentacoordinated aluminum (Alv) are obtained through
the limited hydrolysis of aluminum alkoxides. Here the surface properties of
these aluminas are investigated from the catalytic point of view. The goal
is to obtain geometrical information on the Lewis acid sites.
1H→27A1 (cross-polarization) high resolution MAS
NMR, using chemisorbed NH3 which acts as a XH spin
reservoir, allows the direct observation of surface Al involved in the
catalytic site. The polarization transfer from these protons to surface Al
is remarkably efficient because of the relatively short A1:N-H distance. It
is observed that the main Lewis acid sites are located on distorted
tetrahedral aluminum and pentacoordinated Al. These results are compared to
low temperature infrared data of adsorbed CO.
Stoichiometrically Controlled Solid State Synthesis and Crystal Growth of C60H2
Authors: Morosin B. , Jacobs Joshua , Henderson Craig , Schirber James E. 
Published: April 2011

ABSTRACTWe have demonstrated the direct solid state synthesis of C60H2 by controlling the amount of hydrogen introduced into the reaction with C60. Palladium hydride has been used as the source of hydrogen. The main product 1,2-C60H2 is the isomer previously predicted by computational studies to be the lowest in energy of the possible 23 isomers; in addition, small amounts of the thermodynamically most stable isomer of C60H2, 1,2,3,4-C60H2, has also been obtained. To determine structural parameters by x-ray diffraction, crystal growth from various solvents yielded complex solventcontaining crystals which were examined; however, the complex nature of these crystals have so far precluded detailed crystal structure determinations.
Fullerene/Tubule Based Hollow Carbon Nano-Gears
Authors: Robertson D.H. , Dunlap B.I. , Brenner D.W. , Mintmire J.W. , White C.T. 
Published: April 2011

ABSTRACTWe report the design of several symmetric star-shaped closed carbon cages using ball and stick models. Despite the presence of seven- and eight-membered rings, these hollow carbon sprockets—containing less than 500 carbon atoms—are predicted to be more energetically stable than C60. Also, we show that these sprockets can be connected to capped fullerene tubules to form a nanostructure similar to a mechanical gear and shaft. In addition, using molecular dynamics and a reactive hydrocarbon potential, we show that these gears can be turned against each other at high angular velocities without large deformations. These nanogears illustrate some of the possible complex small structures that can be formed by inserting 5-, 7-, and 8-membered rings in an otherwise graphitic network. These nanogears also show surprisingly robust mechanical properties.
Graphene Nanotubule Cold Field Emission Electron Sources
Authors: Fishbine B. H. , Miglionico C. J. , Hackett K. E. , Hendricks K. J. 
Published: April 2011

ABSTRACTBuckytubes are considered for high current density cold field emitter array electron sources. They may provide more stable, higher-brightness emission than existing cold field emitter arrays.
Growth of Diamond Films Using C3F8AND H2in A New System
Authors: Huangfu Ping , Jin Zengsun , Lu Xianyi , Zou Guangtian , Xiao Huaxian , Chen Tianyi , Liu Mingkai 
Published: April 2011

ABSTRACTIn the present study, the new system used C3F8and H2 as source gases. Filament-assisted chemical vapor deposition was utilized. Continuous diamond films were grown on the Si and Mo substrates without any surface pretreatment. The results of scanning electron microscopy, Raman spectroscopy, X-ray diffraction, and atomic force microscopy measurements indicate that the films deposited on the Mo substrates are of high quality. Homoepitaxial diamond films were grown on the high pressure synthetic single crystal diamond substrates. The results show that in our experimental conditions epitaxial films were easily grown on the (111) synthetic diamond substrates and sometimes epitaxial filmse also grown on the (100) synthetic diamond substrates.
Hydrogen and Halogen Bonding on The Diamond (100)2 × 1 Surface: An Ab Initio Study
Authors: Hukka Terttu I. , Pakkanen Tapani A. , D'evelyn Mark P. 
Published: April 2011

ABSTRACTThis work addresses mechanistic issues in conventional and halogen-assisted diamond growth via ab initio molecular orbital calculations on hydrogenated and halogenated carbon clusters (C9H12Xi, X=H, F, or Cl; i=O, 1, or 2) as models of the dimer-reconstructed diamond (100)2× 1 surface. The dimer bond lengths (XC-CX, XC-C., C=C) and the C-X and C=C π bond energies have been determined along with the effects of lattice constraints. The calculations show that dimer bonds are longer in clusters where only the topmost carbon layer is allowed to relax and the remaining carbon atoms are constrained to lie at diamond lattice positions than in fully relaxed clusters. The calculations also predict that the first C-X bond strength is approximately the same in constrained and fully relaxed clusters and that the second C-X bond is distinctly weaker due to π bond formation, particularly in fully relaxed clusters. These results indicate that the π bond between dimer atoms on the clean (100)-(2× 1) surface is weakened considerably by the constraints imposed by the lattice but is quite important nonetheless.
Synthesis and Characterization of Nitrogen Containing Diamondlike Carbon Films made by ion Beam Deposition
Authors: Shiao Jeansong , Zorman Christian A. , Hoffman Richard W. 
Published: April 2011

ABSTRACTHydrogenated and nonhydrogenated nitrogen containing diamondlike carbon films (NDLC including a-C:N and a-C:N:H) were made in a dual ion beam deposition system. The asdeposited films were characterized by Raman spectroscopy, Rutherford backscattering spectroscopy (RBS) and elastic recoil detection analysis (ERD). The compositional stability of the films at temperatures up to 550°C was examined in situ by both RBS and ERD using a heated sample stage in the scattering chamber. The addition of nitrogen altered the Raman parameters when compared with conventional DLC. At elevated temperatures, the a-C:N films do not suffer nitrogen loss; however, the a-C:N:H films undergo nitrogen and hydrogen loss at 400°C.
Hard High Density Carbon Thin Films for X-Ray Multilayer Optics
Authors: Pedulla Joseph , Bartos Axel , Deslattes Richard D. 
Published: April 2011

ABSTRACTDual ion beam assisted deposition (DIBAD) techniques are known to produce high quality diamond-like carbon films. The reported extreme hardness and high thermal conductivity characteristics of these films have stimulated our investigation of their use as one component of multilayer x-ray optical elements. Non-crystalline carbon films were produced and were characterized by means of highly collimated x-ray refiectometry (λ = 0.154 nn), atomic force microscopy, and IR Raman spectroscopy techniques. They exhibit extreme smoothness at the surface and interface, near diamond density, high hardness, and high uniformity over areas of 0.58 x 10-4 m2. Multilayers have been constructed of this non-crystalline carbon interposed with high electron density materials that have exhibited very good x-ray and EUV optical characteristics at λ = 0.154 nm and at λ = 4.0 – 8.0 nm.
Processing, Structure, and Morphology of Graphitic Carbon Foams Produced from Anisotropic Pitch
Authors: Dutta D. , Hill Charles S. , Anderson David P. 
Published: April 2011

ABSTRACTIn order to produce a three-dimensional interconected graphitic network, foams were produced from carbon fiber precursor pitch and processed similarly to high modulus carbon fibers. Uniform size distributions of open spherical cell graphitic carbon foams were produced by microcellular foam blowing of anisotropic pitch using homogeneous and heterogeneous nucleation. The widths of cell walls and ligaments were in the range of the diameters of pitch-based carbon fibers (7-10 μm) and possessed significant alignment of anisotropic pitch crystallites.
Microstructure and Strain in GaAs/AlGaAs MQW thin Films Bonded to Different Substrates by Eutectic Alloying
Authors: Lin C. H. , Kuo H. C. , Lu Y. , Shen H. , Pamulapati J. , Dutta M. , Cheng J. Y. , Ren F. , Kuo J. M. 
Published: April 2011

AbstractResearch of the strain effect on semiconductors and their heterostructures has generated increasing interests due to its important device applications. We have developed a eutectic bonding technique to create in-plane anisotropic strain in GaAs/AlGaAs multiple quantum well (MQW) thin films. MQW thin films grown on (100) GaAs substrates were bonded to (100) GaAs, (100) Si and Y-cut LiNbO3 submounts with a Au/Sn eutectic alloy. The bonding materials consist of Au/Sn multilayer (80 wt% Au and 20 wt% Sn; 0.95μm) with a Cr (500Å) adhesion layer. The bonding process was optimized by carefully choosing the annealing conditions. After bonding, the substrates of the MQWs were removed by wet chemical etching. The in-plane strain was induced in MQW thin film due to the different thermal expansion between the thin film and submount. The strain was characterized using X-ray rocking curve. The microstructures of bonding interfaces and MQW thin films were examined by scanning electron microscope(SEM) and cross-section transmission electron microscope (XTEM). This bonding technique can be used for many new device applications which take the advantage of in-plane strain, as well as for device integration.
Strain and Interdiffusion Profiles in Epitaxied AU/NI (100) Multilayers Deduced From X-Ray Diffraction Experiments
Authors: Gilles B. , Marty A. 
Published: April 2011

AbstractAu(100)/Ni(100) periodic superlattices have been grown by the MBE technique specially for X-ray diffraction experiments. The nominal number of Ni planes deposited were 1.5, 2, 4 and 5 ML and the thickness of the gold layers was always 1.5 nm. The X-ray profiles have been simulated using a kinematical structure refinement program. The obtained strain profiles are in very good agreement with earlier HREM results. It is shown that a strong interdiffusion occurs during the growth.
Stress in Giant Magnetoresistive Ni66Fe16Co18/Ag Multilayer thin Films
Authors: Jarratt J.D. , Barnard J.A. 
Published: April 2011

AbstractThin film stress has been measured in (Ni66Fe16Co18 25 Å/Ag 50 Å) multilayer thin films that exhibit annealing-induced giant magnetoresistance (GMR) known as ‘discontinuous’ GMR1. This GMR results when NiFeCo layers are broken up into discontinuous ferromagnetic islands or platelets by immiscible Ag atom grain boundary diffusion normal to the film plane. As-deposited films display no GMR and are in compression. An MR value of 5 % with a relatively sharp profile can be induced in a ten bilayer sample annealed at 400°C for 15 min. Annealing generally results in a decrease in the as-deposited compressive stress and can result in tensile stress at high enough temperatures. Interestingly, at the annealing temperatures corresponding to the maximum induced GMR, there is a plateau in the otherwise monotonic decrease in compressive stress with increasing temperature.Stress-temperature plots reveal a plateau in the stress value during the heating of a ten bilayer sample due to plastic deformation in the film via densification. Isothermal stress-time plots done on a single sample show increasing compressive stress relief after each successively higher temperature anneal. The stress was also measured in a single bilayer film with the same volume of film as in a ten bilayer sample but far fewer interfaces. High and low angle x-ray diffraction (HXRD, LXRD) was used to reveal the structural evolution with annealing. Magnetic (M-H) hysteresis measurements revealed increasing coercivity and decreasing induced as-deposited in-plane magnetic uniaxial anisotropy with annealing temperature.
In-Process Evaluation of Kinetic Energy of Sputter Depositing Atoms Using Multijunction Thermal Converters
Authors: Su Quanmin , Huang D. X. , Wuttig Manfred 
Published: April 2011

AbstractThe kinetic energy of Au atoms was evaluated during sputter deposition of Au films using a multijunction thermal convenor (MJTC). The elastic strain energy of the deposited film was simultaneously measured by a high resolution vibrating membrane technique. For the evaluation the flux of Au atoms was treated as an energy flux irradiating a membrane connected to an infinite heat sink. The steady state temperature rise of this membrane under irradiation was used to convert to the kinetic energy of the atomic flux of known deposition rate. The kinetic energy of the sputter depositing Au flux was determined to be in the range of 5 to 18 eV. Only a fraction of it, of the order of 10−4, is converted into mechanical energy manifesting itself as film stress. The results demonstrate the possibility of using MJTCs as kinetic energy monitors during thin film deposition.
Elastic, Transversely Isotropic Film Indented by a Punch; Application to Multilayered Thin Films
Authors: Stone D.S. 
Published: April 2011

AbstractA model calculates the compliance of elastic contact between a punch and bilayer, the latter consisting of a transversely isotropic film on top of isotropic substrate. Used in data analysis, the model helps estimate the Young’s modulus of amorphous silicon (100±20 GPa) layers within amorphous silicon/aluminum multilayer composites deposited on silicon.