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1.
The work undertaken investigates the spectral, thermal and surface characteristics of a random styrene butadiene rubber (SBR)
with monomeric graft(s) of acrylic acid (AA), N-vinyl-2-pyrrolidinone (NVP) or N-isopropylacrylamide (NIPAAm) synthesised using UV polymerisation. The grafted materials were characterised by differential
scanning calorimetry (DSC), modulated differential scanning calorimetry (MDSC), attenuated total reflectance infrared Fourier
transform spectrometry (ATR-FTIR) and atomic force microscopy (AFM). Thermograph analysis has shown an endothermic transition
occurring at ~75 °C for all random SB-g-NVP copolymers, whereas the T
g value for random SB copolymer was found at 60 °C, thus suggesting that a chemical reaction between styrene and NVP had occurred.
Similar thermal profiles to that of random SB-g-NVP copolymers were evident when random SB was UV polymerised with AA. When
NIPAAm was grafted onto random SB, a notable exothermic transition was evident in all samples tested using DSC. It was established
using MDSC that this exothermic transition was caused by the breakdown of crosslinks as a result of UV polymerisation.
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2.
Low-temperature sintered Ca 2Zn 4Ti 15O 36 microwave dielectric ceramic was prepared by conventional solid state reaction method. The influences from V 2O 5 addition on the sintering behavior, crystalline phases, microstructures and microwave dielectric properties were investigated.
The crystalline phases and microstructures of Ca 2Zn 4Ti 15O 36 ceramic with V 2O 5 addition were investigated by X-ray diffraction, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy
(EDS). V 2O 5 addition lowered the sintering temperature of Ca 2Zn 4Ti 15O 36 ceramics from 1140 °C to 930 °C. Ca 2Zn 4Ti 15O 36 ceramic with 5wt% V 2O 5 addition could be densified well at 930 °C, and showed good microwave dielectric properties of ε r ~ 46, Q × f ~ 13400 GHz, and temperature coefficient of resonant frequency (τ f) ~ 164 ppm/°C.
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3.
A number of different families of nanowires which self-assemble on semiconductor surfaces have been identified in recent years. They are particularly interesting from the standpoint of nanoelectronics, which seeks non-lithographic ways of creating interconnects at the nm scale (though possibly for carrying signal rather than current), as well as from the standpoint of traditional materials science and surface science. We survey these families and consider their physical and electronic structure, as well as their formation and reactivity. Particular attention is paid to rare earth nanowires and the Bi nanoline, both of which self-assemble on Si(001).Further information within the topic of this review article, including an up-to-date list of relevant publications, can be found on our Website. The address is:
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4.
Ceramic technology has had an important role in microelectronics since 1960s and ceramic seems to be a continuously developing,
mature technology. Recently, development of low temperature co-fired ceramic technology (LTCC) has been geared up due to the
huge demand of miniaturisation of electronic components. New materials are being developed for extending the demand of wide
range of dielectric properties of LTCC, minimization of shrinkage, cambering of LTCC, high quality of conductors and patterning
etc. This paper deals with formulation of silver conductor inks for LTCC and the effect of ink organics on the LTCC in particular
to cambering/warpage, microstructure development were studied and presented.
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5.
Melt spinning technique was used to synthesize Ni 2MnGa ferromagnetic shape memory alloy ribbons. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) analysis
of the ribbon synthesized at lower wheel speed (20 m/s) reveal the formation of very fine clusters of austenitic phase of
Ni 2MnGa. However at higher wheel speed (30 m/s) the formation of martensite and nanoparticles of Ni 2MnGa with a size range of 10–20 nm in the amorphous matrix is observed. Also an amorphous phase was observed at higher wheel
speed in some areas of the ribbon. Annealing (1000 °C, 1 h) of the ribbon synthesized at higher wheel speed resulted in martensite
and γ (gamma) phases. Amorphous phase, Ni 2MnGa nanoparticles, and the martensite phase are analyzed in detail.
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6.
The microstructure of the compound (“white”) layer formed on the surface of Fe–4wt.%V alloy, by nitriding in a gas mixture
of ammonia and hydrogen at 580 °C, has been investigated by employing light and scanning electron microscopy, X-ray diffraction
and electron probe microanalysis. The compound layer is dominantly composed of γ |-Fe 4N nitride. Quantitative analysis of the composition data demonstrated that V is present in the compound layer as VN precipitates,
i.e. V is not taken up significantly in (Fe, V) nitrides. A mechanism for compound-layer formation has been proposed.
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7.
This article deals with emerging poly-generation schemes that employ pre-combustion decarbonisation of fossil fuels—eventually
with options for geological storage of the CO 2. Inevitably, such schemes are highly complex, and may require new approaches and knowledge on interactions between key components
in large plants, as even new technologies and features are expected to occur in due course as the experience from polygeneration
matures. Reference is made to the European DYNAMIS project and the Sino-European project COACH—both conducted under the auspices
of the European Commission.
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9.
Ground granulated blast furnace slag (GGBFS) reacts with water in the presence of calcium sulfates and alkalis and is frequently used as a partial replacement for portland cement in concrete. The hydration products are known to be slightly different compositionally and morphologically than those of pure portland cement hydration. In this study, a new technique, soft X-ray transmission microscopy, was used to image the hydration of slag in a variety of solutions to investigate the effects of alkali sulfate and hydroxide activators on the morphology of the resulting hydration products. This microscopy method is unique in that it enables high resolution in situ observation and documentation of the formation of hydration products over time in wet samples at atmospheric pressure. 相似文献
10.
Natural fibers are particularly interesting from a materials point of view since their morphology has been tailored to enable
a wide range of macroscopic level functions and mechanical properties. In this paper, we focus on mussel byssal threads which
possess a morphology specifically designed to provide a hysteretic yet resilient large strain deformation behavior. X-ray
diffraction studies have shown that numerous natural fibers have a multi-domain architecture composed of folded modules which
are linked together in series along a macromolecular chain. This microstructure leads to a strong rate and temperature dependent
mechanical behavior and one which exhibits a stretch-induced softening of the mechanical response as a result of the underlying
morphology evolving with imposed stretched. This paper addresses the development of a constitutive model for the stress–strain
behavior of the distal portion of mussel byssal threads based on the underlying protein network structure and its morphology
evolving with imposed stretched. The model will be shown to capture the major features of the stress–strain behavior, including
the highly nonlinear stress–strain behavior, and its dependence on strain rate and stretch-induced softening.
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11.
It has been demonstrated that doping of phthalocyanine (Pc) films by co-sublimation with organic acceptor p-chloranil (CA) initiates alterations in their crystalline structure, depending on the type of Pc molecule. In itself this
factor may inhibit or promote the effect of dopant on the specific conductivity of the particular Pc associated with formation
of the charge transfer complex between Pc and CA.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
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12.
This paper presents the analytical development of a wave equation for real, rapidly altering fields in linear, electromagnetically-coupled
materials. Giving consideration to phenomenology, crystal color symmetry and the laws of Ampere and Faraday, the analysis
is applied to an orthorhombic single-crystal, linear ferroelectromagnet. The results of the analysis are discussed with an
emphasis on the influence of the magnetoelectric coupling coefficient on the velocity expression obtained for electromagnetic
plane waves. The implications of the expressions to modulated optical properties and the use of electromagnetically-coupled
materials are discussed.
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13.
DL_POLY_3 is a general purpose molecular dynamics (MD) simulation package designed to simulate systems of the order of tens
of millions of particles and beyond by efficiently harnessing the power of modern computer clusters. Here we discuss the package
design, functionality and report on performance and capability limits. We then report the application of DL_POLY_3 to study
radiation cascades in Gd 2Ti 2O 7 and Gd 2Zr 2O 7, potential materials for high-level radioactive waste storage and discuss problems associated with the analysis of the cascades.
We see little direct amorphisation but rather the start of a transition to the fluorite structure which is more pronounced
for the Zr than the Ti compound.
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14.
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Drawing on reasoned action and family systems theories, as well as the domestic and international job transfer and relocation,
global assignments, personality and work-life balance research domains, this study examines managers’ willingness to assume
global assignments.
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We propose a multi-factor model and test several hypotheses using survey data collected from 431 global managers and 162 spouses/significant
others that examine the degree to which individual, family, and organizational variables influence managerial willingness
to accept not only the more traditional multi-year, but also the increasingly common traveling and short-term global assignments.
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Results suggest that individual (adventurousness and destination country), family (eldercare, children at home, community
tenure, and spouse/significant other relocation willingness), and organizational (compensatory rewards/benefits and career
fit) factors influence managerial willingness to assume global assignments.
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15.
After 50+ years of research to discover a way of determining the in situ strength of an adhesive bond, a method has been found
to probe this key parameter. The initial testing on composite joints has shown it to be accurate and reliable. While effective,
it is expensive to implement in a production environment and then during the final stages of assembly. A second method of
probing the adherent surface prior to bonding is presented that offers the promise of determining adhesion potential before
final bond consolidation. These new inspection methods should enable significant increases in structural performance for structures
that utilize composite materials. Before examining these two new methods a brief review of past work on adhesive bond strength
determination is presented.
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16.
For every ton of portland cement that is manufactured, approximately half a ton of carbon dioxide is released from calcining
limestone. One method of reducing the carbon dioxide from portland cement production is to reduce or eliminate the use of
limestone through replacement with calcium oxide-bearing waste materials. In this study, portland cement clinker was synthesized
using minimal limestone content and maximal waste material content, specifically fly ash and blast furnace slag. The synthetic
cements were characterized using X-ray diffraction, scanning electron microscopy, and isothermal calorimetry. Results show
that portland cement clinker can be successfully synthesized from a maximam of 27.5% fly ash and 35% slag. The synthetic
cements possessed early-age hydration behavior similar to a commercial Type I/II portland cement. However, the presence of
sulfur impurities contained in waste materials significantly affected phase formation in portland cement clinker.
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17.
We present our results on a newly synthesized bis-phenylazo derivative, namely bisperfluoroalkylsulfonylamino- arylazomethylene-triphenyl-phosphorane
(BAM-TPP). Thin films of BAM-TPP in polymethylmethacrylate (PMMA) matrix were prepared. The films (thickness, d < 60 μm) were exposed to UV-vis light with variable intensity in order to stimulate the photochromic reaction of BAM-TPP.
The resulting absorption changes of the BAM-TPP/PMMA films were investigated by spectrophotometry. The absorption spectra
reveal that BAM-TPP molecules in PMMA undergo photoisomerization with resulting decrease of absorbance in the range 500–700 nm.
Finally, the time response of film transmittance at 514 nm under increasing CW light intensity was recorded, showing that
the reverse photochromic process brings the absorbance back to its pristine value. The obtained films thus proved to be suitable
for optical switching applications.
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18.
The pulsed laser deposition technique was applied to deposit nitrogen-doped yttria stabilized zirconia (YSZ) thin films. The
working parameters were varied in order to achieve a maximal nitrogen content. The films were characterized by SIMS, XPS,
X-ray diffraction and optical spectroscopy. The surface topography was studied by AFM and HRSEM. The influence of the deposition
parameters on the film properties is discussed.
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19.
In order to synthesize compounds of various Perovskite-related structures, we have utilized a novel “melt synthesis technique”
for phosphors rather than the conventional solid state reaction techniques. The solid state reactions require multi-step processes
of heating/cooling with intermediate grindings to make homogeneous samples. However, for the melt synthesis, it is possible
to make a homogeneous sample in a single step within a short period of time (1–60 s) due to the liquid phase reaction in the
molten samples, which were melted by strong light radiation in an imaging furnace. In this study, we have prepared a red-phosphor
CaLaGaO 4:Eu 3+ which has a perovskite—related layered K 2NiF 4 structure. Well-crystallized CaLa 1−x
Eu
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GaO 4 samples with the K 2NiF 4 structure have been obtained up to x = 0.25, but there was the formation of an olivine phase when x = 0.5–1.0. The red emission at 618 nm increased with the increasing value of x up to x = 0.25.
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20.
By dedicated pre-nitriding (at 580 °C in an ammonia/hydrogen gas atmosphere) and de-nitriding (at 470 °C in a hydrogen gas
atmosphere) experiments, performed on Fe-1.04at.%Cr alloy, it could be demonstrated that the uptake of “excess” nitrogen by
the nitrided ferritic matrix is not due to the presence of iron in chromium-nitride precipitates, as it was suggested previously.
The determination of nitrogen-absorption isotherms for these pre-nitrided and de-nitrided Fe-1.04at.%Cr alloy specimens revealed
that the total amount of excess nitrogen in the alloy is composed of two parts: (a) nitrogen adsorbed at the precipitate/matrix
interface, and (b) nitrogen dissolved interstitially in the ferrite matrix strained by the misfit between (coherent) the CrN
precipitates and the matrix.
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