Materials Literature
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The effect of the inclusion of As antisites in the diluted magnetic semiconductor (Ga,Mn)As is studied within density functional theory in the local spin density approximation. In the case of homogeneous distribution of Mn ions we find that the ferromagnetism is largely weakened by the presence of the antisites. This…
NiFe 2 O 4 nanocrystals were dispersed in silica by a sol−gel route. The dried gel was amorphous, in which isolated Fe 3+ ions had a weak interaction with silica matrix, as characterized by a weak IR absorption at ca. 580 cm -1 . Heat treatment at 400 °C resulted in nickel ferrite clusters being partially formed, and…
Experiments on surface melting of several organic materials have shown contradictory results. We study the Van der Waals interactions between interfaces in surface melting of the bulk CH_4 and interfacial melting of the CH_4 film on the MgO substrate. This analysis is based on the theory of Dzyaloshinskii, Lifshitz, a…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTUnusual pH-Dependent Polarity Changes in PAMAM Dendrimers: Evidence for pH-Responsive Conformational ChangesWei Chen, Donald A. Tomalia, and James L. ThomasView Author Information Department of Chemical Engineering and Applied Chemi…
A novel and direct method is described for conjugating protein molecules to luminescent CdSe−ZnS core−shell nanocrystals (Quantum Dots) for use as bioactive fluorescent probes in sensing, imaging, immunoassay, and other diagnostics applications. The approach makes use of a chimeric fusion protein designed to electrost…
The chemical oxidative polymerization of diphenylamine-4-sulfonate (DPASA) was carried out in aqueous and 0.5 M H 2 SO 4 solutions using potassium peroxodisulfate (PDS) as an oxidant. The course of polymerization was followed by UV−visible spectroscopy. The absorbances corresponding to the intermediate and the polymer…
Using the methods of atomic force microscopy, X-ray diffraction and Fourier transform infrared spectroscopy, chemical etching of the (010) surface of flux-grown orthorhombic MoO 3 (α-MoO 3 ) single crystals has been investigated in detail. The (010) surface was etched repeatedly in a 0.08 M NaOH aqueous solution, and…
A [2]-rotaxane Zn 2 −Au + made from a dumbbell component ended by Zn(II) porphyrin stoppers and a ring component incorporating a Au(III) porphyrin has been assembled in 13% yield using the transition metal templating route. 1 H NMR studies show that its conformation in solution is very different from those of its comp…
The soliton model for motion of the 90° partial in silicon has provided an explanation for the large reduction in activation energy (1 eV) which occurs under prolonged exposure to an H plasma. Applying the same theoretical model to diamond yields a drop of 1.6 eV and puts dislocation motion into the realm of the possi…
In many industrial processes, pieces of the same polymer material are brought into contact at a temperature above the glass transition. Interdiffusion takes place across the interface and leads to a strengthening of the junction. Often, a cross-linker agent is also added in order to improve the global mechanical prope…
In environmental catalysis the removal or destruction of S-containing molecules is a very important issue nowadays. The interaction of H 2 S and SO 2 with Cr 2 O 3 (0001), MgO(100) and Cr x Mg 1 - x O(100) surfaces ( x = 0.05−0.08) was studied using synchrotron-based high-resolution photoemission. X-ray absorption nea…
The measured thermal resistance across a thin film deposited on a substrate often includes the internal thermal resistance within the film and the thermal boundary resistance (TBR) across the film-substrate interface. These two resistances are frequently lumped and reported as an equivalent thermal conductivity of the…
The xanthene dye fluorescein was immobilized, via anion-exchange reactions, in the interlayer region and/or on the surface of a synthetic Zn−Al hydrotalcite, prepared by the thermal hydrolysis of urea. Surface uptake was investigated by equilibrating [Zn 0.67 Al 0.33 (OH) 2 ] [CO 3 ] 0.165 0.4 H 2 O with diluted solut…
An anomalously strong volume magnetostriction in Invars may lead to a situation when at low temperatures the dislocation free energy becomes negative and a multiple generation of dislocations becomes possible. This generation induces a first order phase transition from the FCC crystalline to an amorphous state, and ma…
The pair- and three-proton interaction potentials for metal-phase hydrogen are calculated. Irreducible three-proton interactions are shown to be essential in the development of the metal hydrogen structure. Possible manifestations of the three-ion interactions in the structure of quickly quenched metallic systems are…
The adsorption capacities of carbon dioxide on six commercial hydrotalcite-like compounds and the main factors (aluminum content, anion type, water content, and heat treatment temperature) influencing their adsorption capacity at high temperatures have been investigated using a gravimetric technique. There is an optim…
Partial discharge (PD) measurements taken on-site are frequently affected by noise due to external disturbances. This paper describes a noise reduction method that may be used to isolate the PDs from the noise. The basic principles of wavelet de-noising analysis are presented. The PDs are then processed to allow accur…
Among the three main synthetic fibers (acrylics, polyamide, and polyester), the growth of acrylic fibers has been slow. By the end of the year 2000, the annual worldwide production of acrylics is e...
Vibrational modes in suspensions of soft colloids in a fluid can be detected experimentally by Brillouin light scattering. Besides the usual acoustic mode, being essentially the longitudinal phonon of the liquid matrix, an "opticlike" mode is observed in giant starlike micelles at low volume fractions. We propose that…
Dense, crack-free, uniform, and homogeneous (RE2O3)0.08(ZrO2)0.92 (RE=Sc, Y) nanocrystalline thin films were fabricated by a simple sol-gel method and characterized by impedance studies. At temperatures beyond 600 °C, the electrical conductivity of (Sc2O3)0.08(ZrO2)0.92 and (Y2O3)0.08(ZrO2)0.92 nanocrystals in pure cu…