Materials Literature
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Thin-film microstrip lines with a polymer dielectric between ground and signal conductor are proven to be an attractive alternative to coplanar waveguides for (sub)-MM-wave interconnects. Both simulation and electrooptic characterization reveal negligible modal dispersion up to 1000 GHz and low attenuation even if the…
Materials with the skutterudite crystal structure possess attractive transport properties and have a good potential for achieving ZT values substantially larger than for state-of-the-art thermoelectric materials. Studies conducted at JPL on CoAs/sub 3/, RhAs/sub 3/, CoSb/sub 3/, RhSb/sub 3/ and IrSb/sub 3/ have shown…
The chemical effects of ultrasound originate from acoustic cavitation, which produces extremely energetic local transient conditions. In cavitating clouds of bubbles, both sonochemistry and sonoluminescence occur. Spectroscopic analysis of sonoluminescence from hydrocarbons and from metal carbonyls reveal temperatures…
A permeation study using bare Ba0.5Sr0.5Co0.8Fe0.2Ox membranes shows that stable oxygen fluxes are only achieved when operating the membrane at temperatures higher than 1023 K and indicates therefore that short contact time membrane reactors will be most suitable for future upgrading of light hydrocarbons.
Nitrogen limitation induces the nitrogen-regulated (Ntr) response, which includes proteins that assimilate ammonia and scavenge nitrogen. Nitrogen limitation also induces catabolic pathways that degrade four metabolically related compounds: putrescine, arginine, ornithine, and gamma-aminobutyrate (GABA). We analyzed t…
NAD is an indispensable redox cofactor in all organisms. Most of the genes required for NAD biosynthesis in various species are known. Ribosylnicotinamide kinase (RNK) was among the few unknown (missing) genes involved with NAD salvage and recycling pathways. Using a comparative genome analysis involving reconstructio…
A luminescent film with terbium-complex-bridged polysilsesquioxanes has been prepared by sol-gel processing of a new bifunctional monomer that combines the role of a sol-gel molecular precursor with a Tb3+ ion coordinate donor. The emission from Tb3+ ion due to ligand-to-metal energy transfer was observed by UV excita…
Abstract In this article we describe our continuing research on a novel nanocomposite approach for reducing gas permeability through biomedical polyurethane membranes. Nanocomposites were prepared using commercially available poly(urethane urea)s (PUU) and two organically modified layered silicates (OLS). Wide‐angle X…
Variable angle reflectance FTIR spectroscopy was used to investigate the optical properties of indium tin oxide (ITO) and fluorine-doped tin oxide (SFO) thin films in the near-IR spectral region. The reflectance data were used to determine the plasma frequency and the electronic scattering time using the Drude free-el…
The architecture of three-dimensional interconnecting self-organized nanofiber networks from separate needlelike crystals of L-DHL (lanosta-8,24-dien-3beta-ol:24,25-dihydrolanosterol = 56:44) in di-isooctylphthalate has been achieved for the first time, on the basis of the completely new concept of branching creation…
Lactose molecules were installed on the surface of poly(ethylene glycol)-poly(d,l-lactide) (PEG-PLA) block copolymer micelles in the scope of seeking specific recognition by cell surface receptors at hepatic sites. This, in turn, is expected to result in the formation of a complex displaying prolonged retention times…
Pt(II) complexes with a terpyridylazobenzene ligand (tpyAB) were newly synthesized, and their photoluminescence properties by trans-cis isomerization of the azo moiety were investigated. In these complexes, upon excitation with 366-nm light in polar solvents such as DMF, DMSO, and propylene carbonate, trans-to-cis iso…
Self-assembled polypyrrole (PPy) micro/nanotubes, whose diameters and room temperature conductivities were within the ranges of 50–2000 nm and 2–40 S cm −1 respectively, were successfully synthesized by a chemical and electrochemical method in the presence of β-naphthalene sulfonic acid or p -toluenesulfonate acid as…
New micro and sensor systems are being rapidly developed for their application in all technology events in future. The energy consumption of systems incorporated the latest technical advances decreases permanently to the range of only /spl mu/W. For the applications in this low power range (a few 10 /spl mu/W), DTS ha…
Vesicles self-assembled from amphiphilic diblock copolymers exhibit a wide diversity of behavior upon electroporation, due to competitions between edge, surface and bending energies that drive the system, while different viscous dissipation mechanisms determine the timescales. These effects are manifestations of the v…
We present two methods to accelerate first-principles structural relaxations, both based on the dynamical matrix obtained from a universal model of springs for bond stretching and bending. Despite its simplicity, the normal modes of this model Hessian represent excellent internal coordinates for molecules and solids i…
Electronic properties of the metallic pyrochlore oxide Cd2Re2O7 are studied by means of electrical resistivity and Hall measurements. Semimetallic band structures are revealed as expected from band structure calculations. It is found that large changes in carrier density and mass occur at the structural phase transiti…
Dynamic relaxation for nonlinear magnetization excitation is analyzed. For direct processes, such as magnon-electron scattering and two-magnon scattering, the relaxation rate is determined from the linear case simply by utilizing the magnetization oscillation frequency for nonlinear excitation. For an indirect process…
Conducting nanotubes of polyaniline (PANI) about 80–180 nm in diameter were synthesized by a chemical template-free method in the presence of D-10-camphorsulfonic acid (D-CSA) as the dopant, and ammonium persulfate ((NH 4 ) 2 S 2 O 8 ) as the oxidant. The effect of synthetic conditions, such as the molar ratio of D-CS…
Synthesis of Bi2S3 nanotubes from rolling of the quasi-two-dimensional (2-D) layered precursor represents new progress in the synthetic approach and adds new members to the present inorganic fullerene family. These nanotubes display multiwalled structures that resemble that of a multiwalled carbon nanotube. The succes…