Materials Literature
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We calculate the conductance of a circular constriction of radius a in an insulating diaphragm which separates two conducting half spaces characterized by the mean free path l. Using the Boltzmann equation we obtain an answer for all values of the ratio $l/a.$ Our exact result interpolates between the Maxwell conducta…
Thermally initiated cationic ring-opening polymerization of 3-ethyl-3-(hydroxymethyl)oxetane was carried out using benzyltetramethylenesulfonium hexafluoroantimonate as initiator. The resulting hydroxy-functional polyether was thoroughly analyzed by 1H and 13C NMR spectroscopy and found to have a hyperbranched archite…
Currently, the immunohistochemical evaluation of smooth muscle differentiation is usually based on desmin, which also reacts with skeletal muscle and is not present in all smooth muscle tumors, and alpha-smooth muscle actin, which reacts with myoepithelial cells. Neither marker typically reacts with gastrointestinal s…
We analyze specific-heat measurements in the temperature range $1<T<200 \mathrm{K}$ for two types of carbon nanotube samples: multiwalled tubes and ropes of single-walled tubes. The multiwalled tube sample has a specific-heat not unlike that of graphite, which we maintain is reasonable given the structural simil…
In spite of a superficial similarity with gas bubbles, the intimate coupling between dynamical and thermal processes confers to oscillating vapor bubbles some unique characteristics. This paper examines numerically the validity of some asymptotic-theory predictions such as the existence of two resonant radii and a lim…
The dynamic viscoelastic behavior of Poly(l-lactic acid) (PLLA), with molecular weights ranging from 2,000 to 360,000, have been studied over a broad range of reduced frequencies (approximately 1 × 10−3 s−1 to 1 × 103 s−1), using time–temperature superposition principle. Melts are shown to have a critical molecular we…
High surface area conducting polymers with nanoscale dimensions are an important aim for device applications. Here is reported the polymerization and electrochemical oxidation of aniline at multiwalled carbon nanotube electrodes. Polyaniline films formed on these nanotube whiskers are oxidized more easily and produce…
Density functional theory and continuum dielectric methods have been employed to evaluate the free energy of successive aqua-substitution reactions: [Mg(H 2 O) 6- m - n L m L‘ n ] 2+ mz + ny + L z → [Mg(H 2 O) 5- m - n L m +1 L‘ n ] 2+( m +1) z + ny + H 2 O. The ligands L z or L‘ y under consideration are simple organ…
This paper discusses several materials aspects which are important in the development and optimisation of Al2O3:C for both thermoluminescence and optically stimulated luminescence applications, including aspects of crystal growth, luminescence spectra, trap energy distributions and general dosimetric properties.
A simple methodology has been developed to enable a greater enhancement of fluorescence from europium (Eu 3+ )-doped silica gels containing adsorbed silver (Ag) islands. The procedure involves the preparation of Eu 3+ -doped silica gels by a sol−gel method and then immersion in a Ag sol for ca. 48 h to allow the adsor…
▪ Abstract Heat conduction in novel electronic films influences the performance and reliability of micromachined transistors, lasers, sensors, and actuators. This article reviews experimental and theoretical research on heat conduction in single-crystal semiconducting and superconducting films and superlattices, polyc…
Diffuse X-ray scattering from single crystals of metamict zircon reveals residual crystallinity even at high fluences (up to 7.2 × 10 18 α-decay events/g). The experimental evidence does not suggest that radiation-induced amorphization is a “phase transition.” The observations are in good agreement with a nonconvergen…
We study the preparation and capping of silver nanoparticles by several unsaturated long-chain carboxylates. UV−visible and FTIR spectroscopy and high-resolution electron microscopy are used to characterize the effect of the chain length, its configuration, and the degree of unsaturation on the size distribution of th…
The dynamic contact angle formed when a liquid curtain impinges onto a moving solid is measured for aqueous glycerol solutions in different flow regimes. It is usually assumed that the dynamic contact angle is simply a function of the contact-line speed and the material properties of the contacting media. The new resu…
Vanadium oxide nanotubes were prepared in a modified sol‐gel reaction of vanadium oxide triisopropoxide conducted in the presence of the structurally directing hexadecylamine and followed by hydrothermal treatment. The tubes consist of concentric shells of highly crystalline vanadium oxide separated by alternating org…
A new and general way to prepare porous metals with highly ordered 3D arrays of void spaces is reported here. The technique involves filling the spaces between colloidal crystals in a 3D array with a metal ion solution, and removing the solvent to produce a salt skeleton. The skeleton then undergoes chemical transform…
Polyelectrolytes are macromolecules which carry a large quantity of ionizable groups along their chains. By dissolving them in suitable solvents, for example water, these groups dissociate in highly charged macroions and an equivalent quantity of low-molecular counter ions. Through the connection between polymer and e…
The application of the viscous analogy, known as the Hele-Show model, for seepage investigation is demonstrated in the paper. The changes in the viscous properties of the model fluid (glycerine) resulting from the changes of the atmospheric conditions - temperature and humidity, have been taken under consideration as…