Materials Literature
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Field emission of electrons from multiwall carbon nanotubes (MWCNTs) has been investigated in ultra-high vacuum by field emission microscopy (FEM). MWCNTs whose tips are capped by curved graphite layers give FEM patterns consisting of 6 bright pentagons, each of which has a dark region in its center. Interference frin…
The interplay of topological constraints and the persistence length of ring polymers in their own melt is investigated by means of dynamical Monte Carlo simulations of a three-dimensional lattice model. We ask if the results are consistent with an asymptotically regime where the rings behave like (compact) lattice ani…
Molecular-dynamics simulations show that, in an embedded-atom method nickel crystal, interstitial loops made of $〈110〉$ dumbbells may be absorbed by an edge dislocation in two different ways, either being attached to one of the Shockley partials by means of a dislocation junction or being transformed into a double sup…
We present direct evidence of the phase segregation and magnetic-field-induced structural transition in ${\mathrm{Nd}}_{0.5}{\mathrm{Sr}}_{0.5}{\mathrm{MnO}}_{3}$ as proposed earlier [R. Mahendiran et al., Phys. Rev. Lett. 82, 2191 (1999)] for the collapse of the charge-ordered insulating state. The spontaneous $(H=0)…
Powder synthesis and ceramic processing methods have to be improved to take full advantages of new, improved properties of nanocrystalline ceramics. Sintered nanocrystalline ceramics of pure, undoped zirconia are formed from nanocrystalline powder of optimized quality obtained by the chemical vapor synthesis (CVS) met…
Abstract The Horváth‐Kawazoe (HK) model is a widely used method for determining pore‐size distribution in a microporous material from a single adsorption isotherm. The original model, however, suffers from conceptual flaws. The total interaction energy of the adsorbate is underestimated since the adsorbate‐adsorbate i…
The grain-size effect on phase transition induced by pressure in ZnO nanocrystals has been investigated by in situ high-pressure synchrotron radiation X-ray powder diffraction, optical and electrical resistance measurements. The transition pressure of the B4-to-B1 phase transformation for 12 nm ZnO is found to be 15.1…
Plasma display panel technology has the potential to revolutionize the TV market by providing large and flat displays that can be hung on the wall. The authors introduce the principles of PDP technology (see Figure), and discuss their approaches to the problems related to the luminescent materials that must be overcom…
Inelastic neutron scattering was used to systematically investigate the spin-wave excitations (magnons) in ferromagnetic manganese perovskites. In spite of the large differences in the Curie temperatures ${(T}_{C}'\mathrm{s})$ of different manganites, their low-temperature spin waves have very similar dispersions with…
The isothermal crystallization kinetics of poly(trimethylene terephthalate) (PTT) have been investigated using differential scanning calorimetry (DSC) and polarized light microscopy (PLM). Enthalpy data of exotherm from isothermal crystallization were analyzed using the Avrami theory. The average value of the Avrami e…
The transport mechanism of polycrystalline samples ${\mathrm{La}}_{0.825}{\mathrm{Sr}}_{0.175}{\mathrm{Mn}}_{1\ensuremath{-}x}{\mathrm{Cu}}_{x}{\mathrm{O}}_{3}$ $(0<~x<~0.20)$ and the effects of Cu doping have been investigated. It can be concluded that the existence of Cu induces the superexchange interaction a…
Sulfur and sulfur compounds can produce pitting, crevice corrosion, dealloying, stress corrosion cracking, and stress-oriented hydrogen-induced cracking of susceptible metals and alloys. Even though the metabolic by-products of the biological sulfur cycle are extremely corrosive, there are no correlations between numb…
Considerable progress has been made recently in the production of metallic foams. Scale up has progressed so far that widespread commercial use may become a reality in the near future. In this review the merits of the various fabrication techniques are highlighted, while particular emphasis is placed on the demands of…
A Monte Carlo type reconstruction algorithm ( Saxs3D ) to yield low-resolution three-dimensional structures from one-dimensional small-angle X-ray scattering data (SAXS) is presented. It is demonstrated that Saxs3D reliably reproduces the shape of several test protein structures, with their respective SAXS profiles ca…
Both theoretical and experimental results for the dynamics of photoexcited electrons at surfaces of Cu and the ferromagnetic transition metals Fe, Co, and Ni are presented. A model for the dynamics of excited electrons is developed, which is based on the Boltzmann equation and includes effects of photoexcitation, elec…
We present a study of the effect of biaxial strain on the electrical and magnetic properties of thin films of manganites. We observe that manganite films grown under biaxial compressive strain exhibit island growth morphology which leads to a nonuniform distribution of the strain. Transport and magnetic properties of…
Ultrafast laser experiments were used to study electron-phonon coupling in Au nanoparticles in the 2.5 to 8 nm size range in aqueous solution. The electron-phonon coupling constants for these samples were found to be independent of the particle size. This is attributed to a weak interaction between the electron gas an…
Magnetotransport measurements were made on patterned, (110) oriented ${\mathrm{CrO}}_{2}$ thin films grown by the high-pressure, thermal decomposition of ${\mathrm{CrO}}_{3}$ onto rutile substrates. The low-temperature Hall effect exhibits a sign reversal from positive to negative as the magnetic field is increased ab…
Carbon materials processing is an advanced technology due to its aerospace and medical applications. In the aerospace area one can mention the carbon/carbon composites used in rockets and aeronautical brakes; in the medical area one can mention the intrabody implant tools such as heart and hydrocephalic valves and pac…
Impregnation and infiltration of fibrous materials by LC copolyester melts and the blends with viscous thermo-plastic polysulphone were quantitatively described as unsteady and steady stages in terms of rheological characteristics of the melts using an equivalent capillary model. Addition of LC polyester to viscous th…