Materials Literature
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Electrical-transport properties of protonic acid (H2SO4 and HCl)-doped polyaniline (PANI) in an aqueous ethanol medium were investigated in the temperature range 1.8 K ≤ T ≤ 300 K and in a magnetic field up to 8 T. The room-temperature resistivity of HCl-doped PANI is larger than that of H2SO4-doped PANI. The resistiv…
Natural rubber (NR) was blended in various ratios with 29 kinds of tackifier resins. Miscibilities of all the blend systems were illustrated as phase diagrams. From these blend systems, we selected 8 systems having typical phase diagrams (completely miscible, immiscible, lower critical solution temperature [LCST] type…
An induction-coupled plasma reactor was used to thermally decompose polypropylene into propylene and other useful chemicals. From a series of statistically designed experiments, it was found that plasma power input, sheath gas flow rate, central gas flow rate, powder feed rate, quench gas flow rate, and interaction of…
The electronic energy band structure, site- and angular-momentum-decomposed densities of states (DOS) and charge-density contours of perovskite SrTiO 3 in the paraelectric cubic phase are calculated by the first-principles tight-binding linear muffin-tin orbitals method with atomic sphere approximation using density f…
A series of degradable polyurethanes of variable soft segment chemistry and content were synthesized and characterized. An amino acid-based diester chain extender was used to confer degradability and both polycaprolactone diol (PCL) and polyethylene oxide (PEO) were used as soft segments. In addition, the diisocyanate…
The (Na 1 - x K x ) 0.5 Bi 0.5 TiO 3 perovskite solid solution is investigated using x-ray diffraction (XRD) and Raman spectroscopy in order to follow the structural evolution between the end members Na 0.5 Bi 0.5 TiO 3 (rhombohedral at 300 K) and K 0.5 Bi 0.5 TiO 3 (tetragonal at 300 K). The Raman spectra are analyse…
This letter reports the photoluminescence properties of CdSe quantum dots (QDs) embedded in a ferroelectric BaTiO3 matrix. The main emission from the samples has been assigned to the band–edge transition of QDs. With an increase in the heat treatment temperature, the emission peak has been shifted to a longer waveleng…
Both the Hall effect and the ab(')-plane conduction anisotropy are directly addressing the unconventional normal phase properties of the Bechgaard salt (TMTSF)2PF6. We found that the dramatic reduction of the carrier density deduced from recent optical data is not reflected in an enhanced Hall resistance. The pressure…
Scanning tunneling microscopy was used to study molecular order in monolayer organic films formed by solution-phase growth from thermotropic liquid crystal solvents. The films develop macroscopically uniaxial alignment, with adlayer orientation controlled by an external magnetic field through interactions mediated by…
Nanocomposite films consisting of nanosized Ag particles embedded in partially oxidized amorphous Si matrices were prepared by radio frequency cosputtering deposition. Subsequent heat treatment at different temperatures ranging from 200 to 500 °C and its effects on the optical absorption of the films were investigated…
Precise low-frequency light scattering experiments on silica glass are presented, covering a broad temperature and frequency range ( 9 GHz<nu<2 THz). The spectra show a power-law low-frequency wing of the relaxational part of the spectrum with an exponent alpha proportional to temperature in the range 30<T<200 K. A co…
We investigate, through first-principles calculations, the effects of a flattening distortion on the electronic properties of a semiconductor carbon nanotube. The flattening causes a progressive reduction of the band gap from 0.92 eV to zero. The band-overlap insulator-metal transition occurs for an interlayer distanc…
Spin-coherent quantum transport in carbon nanotube magnetic tunnel junctions is investigated theoretically. A spin-valve effect is found for metallic, armchair tubes, with a magnetoconductance ratio ranging up to 20%. Because of the finite length of the nanotube junctions, transport is dominated by resonant transmissi…
The longitudinal d33 piezoelectric coefficient was studied in rhombohedral Pb(Zr0.6Ti0.4)O3 thin films with (111), (100), and “random” orientation. The largest d33 was found in (100)-oriented films and the smallest along the polarization direction in (111)-oriented films. These results are in a good qualitative agreem…
Y 2 O 3 -doped Eu3+ (Y2O3:Eu) nanometer particles (NPs) were synthesized via a chemical route. The particle size estimated by x-ray diffractometry and transmission electron microscopy was about 61 nm. Two photoluminescence peaks were observed at 582 and 587 nm, being attributed to the transition of D05→F1a7 of Eu3+ in…
Individual semiconducting single-walled carbon nanotubes (SWNTs) of various diameters are studied by electrical measurements. Transport through a semiconducting SWNT involves thermal activation at high temperatures, and tunneling through a reverse biased metal–tube junction at low temperatures. Under high bias voltage…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTFuran-Fused TCNQ and DCNQI: Synthesis and PropertiesKazuyuki Takahashi and Keiji KobayashiView Author Information Department of Chemistry, Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8902, Japan Cite this: J. Org. Chem. 2000, 65,…
He I and He II gas-phase photoelectron spectra of Rh 2 (O 2 CCF 3 ) 4 are reported. The electron configuration of the metal−metal bond of Rh 2 (O 2 CCF 3 ) 4 is determined to be σ 2 π 4 δ 2 δ* 2 π* 4 with an ionization energy order of σ ≈ π > δ > δ* ≈ π*. The δ* and π* ionization energies are similar within the range…
Physical vapor deposition of hexadecafluorophthalocyaninatozinc (F 16 PcZn) is performed under UHV conditions from monolayer coverages to an average thickness of about 20 nm on the (100) surfaces of NaCl, KCl, and KBr and on quartz glass as well as on microstructured interdigitated electrode arrays on amorphous SiO 2…
Polyelectrolytes such as single and double stranded DNA and many synthetic polymers undergo two structural transitions upon increasing the concentration of multivalent salt or molecules. First, the expanded-stretched chains in low monovalent salt solutions collapse into nearly neutral compact structures when the densi…