bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rapid Thermal Oxidation of Lightly Doped Silicon in N2O
Authors: Sun S.C. , Wang L.S. , Yeh F.L. , Lai T.S. , Lin Y.H. 
Published: April 2011

ABSTRACTIn this paper, a detailed study is presented for the growth kinetics of rapid thermal oxidation of lightly-doped silicon in N2O and O2 on (100), (110), and (111) oriented substrates. It was found that (110)-oriented Si has the highest growth rate in both N2O and dry O2, and (100) Si has the lowest rate. There is no “crossover” on the growth rate of rapid thermal N2O oxidation between (110) Si and (111) Si as compared to oxides grown in furnace N2O. Pressure dependence of rapid thermal N2O oxidation is reported for the first time. MOS capacitor results show that the low-pressure (40 Torr) N2O-grown oxides have much less interface state generation and charge trapping under constant current stress as compared to oxides grown in either 760 Torr N2O or O2 ambient.
Nanocrystalline Doped Cerium Oxide as a Catalyst for SO2 Reduction by Co
Authors: Tschöpe Andreas , Ying J. Y. , Liu W. , Flytzani-Stephanopoulos M. 
Published: April 2011

AbstractNanocrystalline processing by inert gas condensation has the inherent advantages of generating: (1) high surface area nanoclusters, (2) non-stoichiometric oxides, and (3) high dispersions of dopants. This approach is exploited in the synthesis of fluorite-structured catalysts for SO2 reduction by CO. Nanocrystalline CeO2-x, La-doped CeO2-x, and Cu-doped CeO2-x were produced by magnetron sputtering from a pure or mixed metal target, followed by controlled oxidation of the metallic clusters. The as-prepared doped and undoped nanocrystalline CeO2-x materials were found to be excellent catalysts for complete SO2 conversion to elemental sulfur. Undoped nanocrystalline CeO2-x enabled light-off at 460 °C, a temperature ∼120 °C lower than that over polycrystalline CeO2, which is a novel effective catalyst itself. The high catalytic activity of the nanocrystals was associated with their high concentration of oxygen vacancies. Excellent poisoning resistance was also exhibited by the nanocrystalline CeO2-x samples. These materials have stable activity in the presence of excess CO2.
Microstructural Studies of the WO3/TiO2 Monolayer Catalyst System Using High Resolution Electron Microscopy
Authors: Burrows A. , Kiely C. J. , Joyner R. W. , Knözinger H. , Lange F. 
Published: April 2011

AbstractWe have characterised the WO3T'iO2 (anatase) catalyst system using High Resolution Electron Microscopy. We will show that the overlayer preserves the surface roughness of titania and consists of 2D-hexagonal clusters that have a definite orientation relationship with the support. The contrast observed from these clusters is discussed in terms of existing structural models. A comparison between traditional chemical methods of preparation and simple mechanical mixing is made to assess the effectiveness of the latter to disperse WO3.
The Catalytic Reduction of Nitrogen Oxide Over the Catalysts Supported on Activated Carbon Fibers
Authors: Lu Yun , Fu Ruowen , Chen Yishan , Zeng Hanmin 
Published: April 2011

AbstractCopper-series, nickel-series, and copper-cobalt composite-series catalysts supported on activated carbon fiber were prepared in this paper. Their structures and catalytic activities for the reduction of nitric oxide with ammonia were investigated simultaneously.
Sol-Gel Synthesis of Hybrid Organic-Inorganic Tin Oxide Based
Materials
Authors: Ribot Francois O. , Banse F. , Sanchez C. 
Published: April 2011

ABSTRACTRSn(OAmt)3 with R = n-butyl, n-butenyl or para-styryl, which are
monomeric precursors, have been hydrolyzed. The so-obtained products have
been characterized mainly by 119Sn NMR. In every cases, tin
expands its coordination from 4 to 5 and 6, and hydrolysis yields tin
oxo-hydroxo species of small size. For n-butyl and n-butenyl, a cage-like
tin oxo-hydroxo cluster,
{(RSn)12(μ3–O)14(μ2-OH)6}2+,
was evidenced as the major compound formed. Organic polymerization of the
unsaturated organic groups linked to tin was initiated on the hydrolysis
products and yielded hybrid systems which can be pictured as tin oxo-hydroxo
oligomers attached together by polymeric chains.
Titanate Ceramics from Wet-Chemically Prepared
Powders
Authors: Lin C.H. , Yan T.S. 
Published: April 2011

ABSTRACTA simple method of producing very fine, homogeneous
BaxSr1-xTiO3 powders was
developed in this study by wet-chemically reacting
Ti(0H)4-xH2O, Ba(OH)2, and
Sr(OH)2 as raw materials under 100°C. Relationships were
obtained between particle size, composition, and reaction temperatures,
reaction tunes, Sr/Ba ratios, and (Ba+Sr)/Ti ratios of the solution.Experimental results indicated that the particle size, which was around 40
nm, was both proportional to the reaction temperature as well as independant
of the reaction time. In light of the varying reactivities of Ba and Sr
towards Ti, reaction time was found to be a primary factor which controls
the precise Ba/Sr ratio and (Ba+Sr)/Ti ratio of the titanate powder. A
suitable reaction condition was observed to have prevented by-products
Ba6Ti17O40 or
Ba2Ti04 from being formed.The titanate powders were compressed and sintered for various temperatures.
The compressibility and the sinterability of the powders were obtained. The
microstrucure, dielectric constant and dissipation factor of the titanate
ceramics ware observed and measured. These values sufficiently correlated
with those of the titanate ceramics produced from the powders by the
solid-state sintering method.
Hydroxyapatite Ceramics from Hydrothermally Prepared
Powders
Authors: Lin C.H. , Huang C.W. , Chang S.C. 
Published: April 2011

ABSTRACTHydroxyapatite (Ca5(P04)3(0H)) is an
effective material for artificial human bone production. Hydroxyapatite
powders were hydrothermally produced in this work by reacting
Ca(OH)2 with Na3PO4·12H2O in
an autoclave at various temperature and for various times. The particle size
of hydroxyapatite was observed to be very fine, uniform, around 50 nm, as
well as independent of reaction time.The hydroxyapatite powders were compacted and sintered at various
temperatures for 2 hrs. The density, grain size, and hardness of the
hydroxyapatite ceramics were measured and compared with those of the
hydroxyapatite ceramics produced by the powders from the commercial source.
The hydroxyapatite ceramics from the hydrothermal powders were found to have
a higher density, smaller grain size, and higher hardness.After the hydroxyapatite ceramics were dipped in a simulated biological body
liquid for 10 days, the density and hardness of the hydrooxyapatite ceramics
from the hydrothermal powders were less deteriorated than those of the
hydroxyapatite ceramics from the commercial powder.
Monophasic Pre-Mullite Gels Prepared by a Nonhydrolytic
Process
Authors: Acosta Sylvie , Corriu Robert J.P. , Leclercq Dominique , Mutin P. Hubert , Vioux Andre 
Published: April 2011

ABSTRACTA nonhydrolytic sol-gel route to aluminosilicates is proposed which avoids
the problems associated with different hydrolysis rates for the precursors.
Two pre-mullite gels (Al2O3/SiO2=3/2) were
prepared in two different ways. The conversion to mullite was studied as a
probe for chemical homogeneity. The results indicate that a monophasic
precursor (i.e. homogeneous at the atomic level) may be easily obtained by
etherolysis of a mixture of SiCl4 and AlCl3.
Sol-Gel Synthesis of Protoenstatite
Authors: Jones Steven A. , Burlitch James M. 
Published: April 2011

ABSTRACTProtoenstatite, a high-temperature polymorph of enstatite
(MgSiO3), is generally not stable at room temperature, and is
difficult to synthesize. Using a recently developed, hydrogen
peroxide-assisted, sol-gel synthesis, protoenstatite was synthesized in a
form that was stable at room temperature. Its crystallization was strongly
dependent on processing conditions, particularly on the manner in which the
xerogel was formed and fired. Xerogels prepared by evaporation, sprav-drying
and freeze-drying were compared by XRD, HTXRD, BET, TG/DTA, and
29Si NMR methods. When samples were prepared by evaporation or
spray-drying, the result was a mixture of polymorphs. Only the freeze-dried
precursor yielded protoenstatite at a lower temperature and within a shorter
time than any previously reported.
Electrochemical Synthesis and Characterization of
NaCuO2
Authors: Roberts Gerald L. , Kauzlarich Susan M. 
Published: April 2011

ABSTRACTNaCuO2 has been prepared via electrodeposition from a sodium
hydroxide/potassium hydroxide melt and characterized by single crystal and
powder X-ray diffraction, magnetic susceptibility, and resistivity. Clusters
of blue-black plate-like and needle crystals are grown at positive
potentials on a platinum anode with a platinum or a zirconium crucible
serving as the cathode and a platinum reference electrode. Details of the
electrochemical procedure are described, along with a cyclic voltammogram.
NaCuO2 exhibits temperature independent paramagnetism over the
temperature range 30 – 300 K. Its room temperature resistivity is greater
than 106 Ω-cm.
Properties and Characterization of Porous Material Prepared by
Hydrothermal Treatment of Kaolin
Authors: Malla Prakash B. , Arrington-Webb Lee Ann 
Published: April 2011

ABSTRACTA kaolin was hydrothermally treated with various amounts of NaOH and KOH at
150°C for 15 min to chemically aggregate the kaolin plates in a structured
configuration. X-ray powder diffraction analysis indicated that kaolin was
the only crystalline phase present. Chemical analyses showed that about 0.25
- 1.1 % Na2O and 1.2 - 5.0 % K2O were trapped in the
solid phase depending on the reaction conditions. Mercury porosimetry
indicated a highly porous nature with pore volumes of 0.3 - 1.4 ml/g and
median pore sizes of 0.06 - 0.3 μm. Scanning electron micrographs showed
that the aggregation was achieved by surface modification and random
association (edge to edge and face to edge, face to face) of the particles.
Measurement of light scattering coefficient of the coating showed an
increase of ∼350% in scattering compared to that of the precursor kaolin.
These materials are useful in imparting highly opacifying properties to
paper and paint. They are also potentially useful as catalysts, catalyst
supports, and in other applications which demand a high light scattering
ability and macroporous nature.
Microporous Alumino-Silicate Gels Synthesized by Sol-Gel
Method
Authors: Chu L. , Yaluris G. , Zeltner W. A. , Anderson M. A. 
Published: April 2011

ABSTRACTMicroporous alumino-silicate gels were prepared by the sol-gel method. The
Al cations were incorporated into these systems by mixing an aluminum
nitrate solution into silica water based sols under controlled pH
conditions. The micro structure as well as the form of the products are
influenced by the amount of Al additives. Al cations have significant
effects on the properties of silica sols and gels. The alumino-silicate gel
has micro porosity with surface area as high as 300 m2/g even
after calcining at 900 °C for one hour. Strong negative charge is found on
these alumino-silicate surfaces in aqueous solution indicating the Al
cations have been substituted isomorphically into the Si sites in the
framework of silica.
CdSe Nanocrystals Formation in Silica Sonogels
Authors: Hummel Daniele C. , Torriani Iris L. , Ramos Aline Y. , Craievich Aldo F. , De La Rosa-Fox Nicolas , Esquivias Luis 
Published: April 2011

ABSTRACTHost-matrix gels were prepared by hydrolysis of TEOS with the addition of
cadmium nitrate, formamide as DCCA (drying control chemical additive) and
submitted to a preselected dose of high power ultrasound. The impregnation
of the dry “sonogel” with KSeCN solution under vacuum conditions promoted
the formation of the CdSe nanocrystals and enhanced the mechanical
properties of the matrix. A transparent red xerogel was obtained and
characterized by optical spectroscopy, TEM and SAXS measurements. The
results support a structural model of a porous matrix containing CdSe
nanocrystals exhibiting a bimodal size distribution that depends on the Se
content of the impregnating solutions. The blue shift of the optical
absorption bands reveal the quantum-size confinement effects of CdSe
nanocrystals.
Morphology of TiO2 Aerogels
Authors: Zhu Zhu , Tomkiewicz Micha 
Published: April 2011

ABSTRACTThe morphology of titanium dioxide aerogel was studied using a variety of
complementary techniques that include: nitrogen adsorption, Small-Angle
Neutron Scattering (SANS), scanning and transmission electron microscopies
(SEM/TEM) and X-ray diffraction. Since these techniques sense different
components of the microstructure, global parametrization should coalesce the
results into a uniform framework.
Nano Sized Pd Particles In A SiO2 Matrix By Sol-Gel
Processing
Authors: Burkhart T. , Mennig M. , Schmidt H. , Licciulli A. 
Published: April 2011

ABSTRACTPd colloid containing Ormocers (organically
modified ceramics) have
been prepared from Pd amino complexes of the type
Pd[NH2CH2CH2NH(CH2)3Si(OMe)3]2ac2
by hydrolysis and condensation (sol-gel reaction) of the silane together
with Si(OEt)4 and
Si(OEt)3(CH2)3OCH2CHCH2O.
The amino complex formation is necessary to avoid spontaneous reduction and
uncontrolled colloid formations in the liquid phase. This synthesis route
leads to Pd colloid containing powders and coatings on glass. By thermal
curing (temperatures up to 500 °C) using different atmospheric conditions
(N2, Ar, H2/N2) brown to deep black
coatings on glass with transmission values from 80 to 0 % can be obtained.
The average particle size can be controlled by varying the molar ratio of
the used Pd salt (Pd(ac)2) and the aminosilane.
Sol-Gel Processing and Structure Development of Lead Titanate
Particles
Authors: Wright John S. , Francis Lorraine Falter 
Published: April 2011

ABSTRACTSpherical particles of lead titanate, PbTiO3, (PT) were prepared
from partially hydrolyzed alkoxide solutions modified with benzoic acid.
Modified and aged alkoxide solutions were added dropwise to isopropyl
alcohol, forming particles (0.2 to 1.0 μm in diameter). FTIR spectroscopy
results demonstrate chelation of the PT alkoxide which prevented the
formation of an extended gel network. Diffuse reflectance FTIR (DRIFT)
spectra indicate the benzoate ligands are present until 450°C; TGA results
show significant weight loss at 450°C. PT particles crystallize into the
perovskite phase at =450°C, as determined by DTA and XRD. The relatively low
crystallization temperature may be due to the effect of benzoate ligands on
amorphous structure and presence of internal surfaces.
Clay-Polymer Nanocomposites: Polyether and Polyimide
Systems
Authors: Pinnavaia Thomas J. , Lan Tie , Kaviratna Padmananda D. , Wang Muh S. 
Published: April 2011

ABSTRACTA new type of clay-polyether nanocomposite has been prepared by the
self-polymerization of diglycidyl ether of bisphenol A in the galleries of
acidic alkylammonium ion exchanged forms of montmorillonite. The acid
catalyzed intragallery polymerization process leads to the spontaneous
exfoliation to the 10Å-thick clay layers. Intra- and extragallery
polymerization processes are distinguishable by DSC.Clay-polyimide hybrid composites have also been prepared by the
intercalation of polyamic acid in montmorillonites and subsequent thermal
conversion to polyimide. In contrast to the completely exfoliated
clay-polyether system, the polyimide system contain regularly intercalated
clay aggregates in the polymer matrix. Although regular face-face clay layer
aggregation is extensive, the clay-polyimide hybrid composite films exhibit
greatly improved CO2 barrier properties.
New Routes to Silicic Acid Containing Inorganic-Organic Hybrid
Precursors and Polymers
Authors: Hoebbel D. , Endres K. , Reinert T. , Schmidt H. 
Published: April 2011

ABSTRACTIn view of the outstanding role that silicic acids (sa.) play in inorganic
materials a survey will be presented regarding the possibilities of the
integration of sa. in organic matrices via chemical reactions. The objective
is to combine the advantageous properties of the silicic acid with those of
the organic compounds in order to generate novel materials. The reactions of
silicic acids with organic molecules, as studied by 29Si NMR
spectroscopy, are described using the silicic acid
H8Si8O20 with a defined double four-ring
structure as an example. By silylation of the hydrophilic
H8Si8O20 its functional organophilic
derivatives were synthesized. The s.a. derivatives with epoxy-, alkoxy-,
HSi-, ketoester or unsaturated groups are capable of condensation,
polymerization, complexation or additive reactions leading to reactive
inorganic-organic precursors or polymers with the defined silicic acid unit.
The synthesis and structure of the following s.a. containing precursors and
polymers will be reported, (a) inorganic-organic polymers with a high
content of silanol groups, (b) microporous polymers free of silanol groups
and (c) metal (Al, Zr) alkoxide complexes attached to defined silicic acid
units. The model reactions of the double four-ring silicic acid derivatives
can be transferred to technical silicic acid solutions prepared
from water glass. The presented reaction pathways are a basis
for the preparation of a great variety of new inorganic-organic compounds
with tailor-made structures and properties which can be used for highly
homogeneous and stoichiometric materials.
Synthesis and Characterization of Semiconductor Nanop
Articulates
Authors: Herron Norman , Wang Ying 
Published: April 2011

ABSTRACTSemiconductor nanoparticulates are important materials bridging the gap in
size and electronic properties between molecular species and bulk materials.
Synthetic approaches to producing controlled sized clusters of this sort
will be described, covering physical encapsulation in zeolites or porous
glass and extending to discrete syntheses using surface terminating
reagents. The optical properties of the resultant materials will be
described in detail and the structural topology of the clusters elucidated
by combined powder and single crystal diffraction. Thermal transformations
of these clusters into bulk materials will be tracked and the processing
possibilities explored for the production of polycrystalline films and
polymer/semiconductor composites. Photoconductivity in the latter composites
will be described.
Synthesis and Properties of Ytterbium Doped C60
Authors: Irons Stephen H , Klavins P. , Liu J.Z. , Lan M.D. , Shelton R.N. , Song K. , Kauzlarich S.M. 
Published: April 2011

ABSTRACTYtterbium doped C60 (YbxC60) has been synthesized through the use of a liquid ammonia intercalation route. This allows for precise control of the stoichiometric composition. Magnetization data were taken in fields up to 1 Tesla and temperatures between 5 and 300 K on samples with 1≤X≤5. We find the ytterbium introduces significant anisotropies into the system which give rise to long time magnetic relaxation effects that persist to high temperatures. We suggest the existence of an amorphous structure to explain the results.
Low Temperature Diamond Growth With CF4 Addition in A Hot Filament Reactor
Authors: Corat Evaldo. J. , Trava-Airoldi V. J. , Leite Nélia F. , Peña Angel F.V. , Baranauskas Vítor 
Published: April 2011

ABSTRACTIn this work we show that the addition of a small amount of CF4 to a regular CH4 -H2 gas mixture allows diamond growth at lower temperatures with reasonable growth rates. We used a hot filament assisted reactor and observed diamond growth with a substrate temperature as low as 390 ଌ. We present a comparative study for the growth dependence on substrate temperature with and without CF4 addition in the gas mixture. The growth rate is measured by post growth weighting with a micro balance. Raman spectroscopy, SEM and AFM images show the good quality of the films grown at low temperatures when CF4 is added to the feeding gas.
The Growth of Amorphous CuxTi1-x Films: Relationship Between Intrinsic Stresses and Microstructure Observed by STM
Authors: Von Hülsen U. , Geyer U. , Dina S. , von Minnigerode G. 
Published: April 2011

AbstractThe evolution of the surface topography of thin amorphous Cu-Ti films during the film growth is investigated by scanning tunneling microscopy. The films begin to grow with smooth surfaces until the film thickness reaches a critical value. Then, within a small thickness interval, a grainy microstructure of the film develops which looks very similar to the microstructure of polycrystalline films. Measurements of the intrinsic macroscopic stress in these films during the film growth show compressive stresses in the early growth stages. Then a change to tensile stresses accompanies the change in the surface topography within the same thickness interval. Both, the surface topography and the intrinsic stresses, are always correlated and depend on the deposition temperature and on the film composition. We discuss implications of these observations on the origin of macroscopic intrinsic tensile stresses in amorphous transition metal films.
Potential Limitations of Conventional Photomasks Due to Inherent Internal Stress - the Need for an Alternative Opaque Layer
Authors: Cairns James A. , Liu Chi-Wing , Hourd Andrew C. , Keatch Robert P. , Lawrenson Brian 
Published: April 2011

AbstractConventional photomasks consisting of chromium films on fused silica or glass substrates are widely used. However, it is becoming apparent that interfacial stress between the chromium and the transparent substrate, as well as the need for wet chemical processing for pattern production, will ultimately limit a photomask’s ability to be patterned reproducibly. An alternative approach is to chose an opaque layer which exhibits minimum interfacial stress with respect to the substrate while having the ability of being patterned by fluorocarbon gas plasma processing.This work describes the use of silicon/germanium as an alternative opaque layer, which can be deposited uniformly by co-sputtering and patterned by fluorocarbon reactive ion etching. The suitability of the material in terms of interfacial stress is demonstrated by the use of microfabricated silicon dioxide cantilever structures. In addition, the influence of Si/Ge ratio on optical properties, the plasma processing performance, and chemical compatibility with the rest of the photomask making process is described.
Metallic thin Films on Ceramic Substrates: Stress-Enhanced Intermixing and Spinel Formation
Authors: Pirouz P. , Ikuhara Y. , Flynn C. P. 
Published: April 2011

AbstractMultilayers of vanadium and MgO with different layer thicknesses were grown by molecular beam epitaxy (MBE) and the V/MgO and MgO/V interfaces were investigated by cross-sectional high resolution electron microscopy (HREM). For the smallest layer thickness of 5 nm, the vanadium and MgO films were coherent with each other and no misfit dislocations were observed. For the larger layer thicknesses of 10 nm and 50 nm, the vanadium surface exhibited undulations, and for the largest thickness, interdiffusion had occurred between the MgO film and the underlying V substrate and an interfacial spinel phase had formed. These observations are discussed in terms of the morphological instabilities of the strained vanadium film as it grows on the MgO substrate.