Materials Literature
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PLA/PEO/PLA triblock copolymers bearing short poly( l -lactic acid) blocks, with the number average degree of polymerization of each PLA block PLA = 2, 4, 8, and 12, were synthesized by ring opening polymerization of l -lactide initiated by poly(ethylene glycol) in the presence of CaH 2 . The length of PEO blocks was…
Colloidal gold nanoparticles with an average radius of 15 nm have a surface plasmon absorption band at 530 nm. Excitation by laser pulses of 450 fs duration, and wavelength of 600 or 380 nm “bleached” the plasmon band and produced a transient absorption at the wings of the “bleach” spectrum. The transient absorption w…
Macrocyclic dicopper(II) complexes derived from 2,6-di(R)formylphenols and various linking diamines are surveyed and their magnetic and structural properties assessed. For those systems with "flat" dinuclear centers and no electronic perturbations associated with electron-withdrawing ligands or ligand groups, the comp…
The preparation, crystal structures, and electric and magnetic properties of (BETS) 2 MX 4 molecular conductors (BETS = bis(ethylenedithio)tetraselenafulvalene; M = Mn 2+, Fe 3+, Co 2+, Ni 2+, Cu 2+; X = Cl, Br, CN) are reported. Resistivity measurements down to 2 K reveal the coexistence of the BETS π conduction elec…
The crystallization boundaries of small, attractive particles are found to be identical when interactions are modeled as adhesive hard spheres. Based on experimental results and the attraction range, we conclude that solubility is insensitive to interaction details and various colloidal particles will only display equ…
Orientational ordering of faceted nanocrystals in nanocrystal arrays has been directly observed for the first time, by use of transmission electron microscopy imaging and diffraction to resolve the structure of thin molecular-crystalline films of silver nanocrystals passivated by alkylthiolate self-assembled monolayer…
The oxidation of formic acid on thin, epitaxially-grown Pd overlayers on Au and Pt single crystal electrodes was studied as a function of overlayer thickness ranging from submonolayer coverages up to the equivalent of 10 monolayers. The results were compared with those for massive Pd single crystal surfaces. The elect…
Four different kinds of C 60 -linked zincporphyrins have been prepared by changing systematically the linking position at meso -phenyl ring from ortho to para and their photophysical properties have been investigated. Regardless of the linkage between the two chromophores, photoinduced charge separation (CS) and subse…
Temperature-programmed isotopic exchange of 18 O 2 with 16 O of several oxides was carried out in the 200−900 °C temperature range. The oxides can be ranked according to their maximal rates of exchange obtained at the following temperatures: CeO 2, 410 °C ≫ CeO 2 -Al 2 O 3, 480 °C ≈ MgO, 490 °C > ZrO 2, 530 °C ≫ γ-Al…
Smart Materials Technology and Control Applications. Modeling Aspects of Shells, Plates and Beams. Patch Contributions to Structural Equations. Well-Posedness of Abstract Structural Models. Estimation of Parameters and Inverse Problems. Damage Detection in Smart Material Structures. Infinite Dimensional Control and Ga…
The rational design, synthesis, and characterization of the building blocks obtained by the esterification of the first generation of tapered monodendrons 3,4,5-tris( p -dodecan-1-yloxy)benzoic acid ( 12-AG ) and 3,4,5-tris[ p -( n -dodecan-1-yloxy)benzyloxy]benzoic acid ( 12-ABG ) containing semifluorinated dodecyl g…
Sulfonated polyaniline (SPAN) is a self-doped conducting polymer. It has a high water solubility and a novel pH-dependent DC conductivity that is of interest for fundamental science and also for applications in such areas as rechargeable battery and pH control technologies. We report here the extensive characterizatio…
Alumina mesophases have been synthesized by reacting aluminum alkoxides and carboxylic acids with controlled amounts of water in low-molecular-weight alcoholic solvents. Calcination of these materials yields aluminas that are thermally stable to 1073 K and contain randomly ordered pores. Specific surface areas as high…
To determine if high-dose gadolinium chelates are less nephrotoxic than iodinated contrast. Records of 342 patients who had received high-dose gadolinium (.2 to .4 mmol/kg) for magnetic resonance imaging were reviewed to identify patients who had also received iodinated contrast for radiographic examinations. Their cl…
Sequential addition of anionic and cationic polyelectrolytes may lead to the formation of multilayers at a solid surface. The buildup of such multilayers is characterized by a stepwise increase of the adsorbed amount and layer thickness and by alternating highly positive and highly negative values for the ζ-potential.…
Alternating current (ac) magnetic susceptibility data are presented for six distorted cubane complexes of the composition [Mn IV Mn III 3 O 3 X]. Each of these complexes has a well isolated S = 9 / 2 ground state. There is zero-field splitting (ZFS) in the ground states where D, the axial ZFS parameter, is found to be…
Electronic and chemical passivation of CdSe nanocrystals (quantum dots) has been achieved with a thin ZnSe overlayer grown in solution from trioctylphosphine selenide and diethylzinc. Layered particles with a [ZnSe/CdSe] ratio ranging from 0 to ∼5.0 were prepared and characterized by optical absorption spectroscopy, p…
The structure, dynamics, and thermodynamics of gold nanocrystallites passivated by alkylthiolate monolayers were investigated, using molecular dynamics simulations, in different environments as isolated gas-phase clusters, when adsorbed on a graphite surface, and when assembled into three-dimensional superlattices. Th…
A template carbonization technique was applied to prepare carbon nanotubes and submicron-tubes in one dimensional channels. An anodic aluminum oxide film that has uniform and straight channels with a diameter at the nanometer level was used as a one-dimensional template. The pyrolytic carbon deposition on the channel…
Very stable organically modified MCMs are prepared by a simple one-step procedure from readily available starting materials.