Materials Literature
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A new mechanism is proposed to explain the slow conductance fluctuations in the conductance-gate voltage plot observed in the nanotube electron resonators. It is found that the slow conductance fluctuation is an intrinsic quantum interference phenomenon and exists in all metallic nanotube resonators except zigzag ones…
The non-linear electrical behavior of zinc oxide, used to practical advantage in surge arresters on distribution power systems, has been replicated in epoxy resin, which has been filled with an appropriate volume fraction of this intrinsically semi-conducting material. Comparison has been made with epoxy resin contain…
Abstract Quantum dots (2–5 nm) of copper and copper/palladium mixtures are found to be good catalysts for Suzuki cross‐coupling. The catalysts are applicable to a wide range of iodo‐ and bromoaryl substrates, and give moderate yields using chloroaryl substrates. Cluster activity and stability is found to depend strong…
A novel method has been used to synthesize rare earth oxide nanoparticles. Sm and Nd hydride nanoparticles were first produced by a hydrogen plasma−metal reaction. The evaporation rate of Sm is about three times that of Nd. Nd 2 O 3 nanoparticles were then directly synthesized from the passivation of Nd hydride nanopa…
Abstract Diarylethenes having a fluorescent indole ring as the aryl group 1a and 2a were synthesized. Upon alternate irradiation with 366 nm and visible (λ > 480 nm) light, 1a underwent reversible photocyclization reactions to produce closed-ring isomer 1b. The fluorescence intensity also reversibly changed alo…
This paper describes a simple and reliable method of improving the surface insulation strength of a spacer used in vacuum. The method is to roughen the spacer surface to an average roughness R/sub a/ higher than 1 or 2 /spl mu/m. The material of the spacer examined is SiO/sub 2/, PMMA, PTFE or Al/sub 2/O/sub 3/ and th…
For more than 25 years, various techniques have been introduced for the nondestructive measurement of the space charge distribution in solid dielectrics. All these techniques can be classified into a set of three methods: (i) the thermal method, (ii) the pressure-wave-propagation method and (iii) the electro-acoustic…
Abstract Commercially available biodegradable aliphatic polyesters, i.e., high molecular weight poly(ϵ‐caprolactone) (PCL) and polylactide (PLA), were melt blended with a well‐known natural and biodegradable polysaccharide: starch either as corn starch granules or as thermoplastic corn starch after plasticization with…
A protein Raman spectrum comprises discrete bands representing vibrational modes of the peptide backbone and its side chains. The spectral positions, intensities, and polarizations of the Raman bands are sensitive to protein secondary, tertiary, and quaternary structures and to side -chain orientations and local envir…
The use of organometallic precursors allows the synthesis in mild conditions of nanoparticles of uniform small size (1–3 nm) and of clean surface, which can be stabilized by polymers or ligands. These nano-objects display an interesting surface chemistry comparable to that of molecular species. This involves classical…
Pectin and lignin are both very important noncellulosic substances occurring in hemp fibers. The main task in preparing hemp fibers for textile applications is to remove these noncellulosic substances without damage to the fiber cellulose. Pectin and lignin in hemp before and after chemical processing are characterize…
Two important advances over the past 40 years enable the optimization and management of the structural integrity of components in high performance applications. First, the solid mechanics conununity established linear elastic fracture mechanics as the premier framework for modeling the damage tolerance of fracture cri…
We have prepared samples of nominal type Ba 8 Cu x Ge 46− x by induction melting and solid state reaction. Analysis shows that these materials form type-I clathrates, with a copper content between x = 4.9 and 5.3, nearly independent of the starting composition. We used x-ray powder diffraction and single-crystal elect…
The microstructure in Y 2 O 3 ‐stabilized tetragonal zirconia polycrystal (Y‐TZP) sintered at 1300°–1500°C was examined to clarify the role of Y 3+ ions on grain growth and the formation of cubic phase. The grain size and the fraction of the cubic phase in Y‐TZP increased as the sintering temperature increased. Both t…
Progress in tissue-engineering research has renewed optimism about the possibility of constructing a physiologically functional blood vessel substitute in the laboratory. To this end, we have explored the use of defined mechanical stimulation to further the development of vascular tissue analogs. We now report our fin…
We present first-principles transport calculations for ${\mathrm{Sb}}_{2}{\mathrm{Te}}_{3}$ using the linearized-augmented plane-wave method and the relaxation time approximation. We considered the effects of hydrostatic pressure and uniaxial stress up to 4 GPa. Doping was included for electrons and holes at levels up…
It is shown that in a heterostructure where screening is eliminated, the Ampére-Maxwell law of electrodynamics implies that a dc or ac spinomotive force can be inudced with a time rate of change of a transverse electric field, and the magnetic analog of Ampére law implies that a dc or ac spin current can generate a tr…
Challenges facing the scaling of microelectronics to sub-50 nm dimensions and the demanding material and structural requirements of integrated photonic and microelectromechanical systems suggest that alternative fabrication technologies are needed to produce nano-scale devices. Inspired by complex, functional, self-as…
Contrasting magnetic properties were obtained from bulk Mn-doped ZnO synthesized under different processing conditions. While a ferrimagnetic phase transition was observable in a Zn0.95Mn0.05O sample processed at 1170 K, no such transition was found for a sample with the same composition processed at 1370 K. The detai…
We deposited graded-index SiO2 films using glancing angle deposition to produce high-transmission antireflection coatings on glass. Because of the accurate control over the thin-film microstructure provided by this technique, we were able to create graded densities with a Gaussian profile resulting in transmission val…