Materials Literature
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We report on the interaction of light with a particular class of media---wet gels, which in contrast to sols of nanoparticles possess a macroscopic bulk structure, and which differ from conventional solids by the existence of the internal liquid-solid interface. We show, taking an absorption cross section of trapped e…
This work describes the use of atomic force microscopy (AFM) to measure the size of dendrimer-stabilized Pt nanoparticles (Pt DNs) deposited from aqueous solutions onto mica surfaces. Despite considerable previous work in this area, we do not fully understand the mechanisms by which PAMAM dendrimers template the forma…
Layered organic superconductors are on the verge of the Mott insulator. We use the Gutzwiller variational method to study a two-dimensional Hubbard model including a spin exchange coupling term as a minimal model for the compounds. The ground state is found to be a Gossamer superconductor at small on-site Coulomb repu…
Porous nanostructured mixed-conducting materials with dual-scale porosities are fabricated using foam-like templates. The porous structures, as shown in the Figure, contain large pores (0.8–1.5 μm) for rapid gas transport and small pores (≈ 2.5 and 35 nm) for fast electrochemical reactions that require large surface a…
Ferroelectric nitrogen-doped Bi4Ti3O12 (BIT) and nitrogen-substituted BIT (N-BIT) thin films are prepared by an radiofrequency-magnetron-sputtering method such that nitrogen atoms are incorporated into oxygen sites. The remnant polarization Pr and the coercive field Ec of the nitrogen-doped BIT are enhanced relative t…
ADVERTISEMENT RETURN TO ISSUEPREVLetterNEXTComment on "Gold Nanoshells Improve Single Nanoparticle Molecular Sensors"Jin Z. Zhang, Adam M. Schwartzberg, Thaddeus Norman,, Christian D. Grant, Jun Liu, Frank Bridges, and Tony van BuurenView Author Information Department of Chemistry, University of California, Santa Cruz…
We have investigated electronic structures and magnetic properties of double perovskite $\mathrm{La}A\mathrm{V}\mathrm{Mo}{\mathrm{O}}_{6}$ $(A=\mathrm{Ca},\mathrm{Sr},\mathrm{Ba})$. The normal metallic and ferrimagnetic states are found to be ground states, contrary to the experimental speculation of possible candida…
The structure, stability, and electronic properties of a fivefold surface of an icosahedral $(i)$ Al-Pd-Mn alloy have been investigated using ab initio density-functional methods. Structural models for a series of rational approximants to the quasicrystalline structure of bulk $i$-AlPdMn have been constructed using th…
Oxalyl amide derivatives bearing 4-dodecyloxy-stilbene as a cis-trans photoisomerizing unit were synthesized. The trans derivative acted as a versatile gelator of various organic solvents, whereas the corresponding cis derivative showed a poor gelation ability or none at all. In diluted solution (c = 2.0 x10(-5) mol d…
Several new series of dendrimers containing a single redox-active 4,4'-bipyridinium (viologen) residue were synthesized and characterized. In these dendrimers, the viologen group is covalently attached to the apical position of a Newkome- or Frechet-type dendron, ranging in size from first to third generation of growt…
The term “wood-plastic composites” refers to any number of composites that contain wood (of any form) and either thermoset or thermoplastic polymers. Thermosets or thermoset polymers are plastics that, once cured, cannot be remelted by heating. These include cured resins, such as epoxies and phenolics, plastics with w…
Static and dynamic laser light scattering techniques are used to monitor the slow self-assembly of 2.5-nm-diameter, hollow spherical, fully hydrophilic heteropolyoxometalate {Mo72Fe30} macro-ions into single-layer vesicle-like "blackberries" (averaging approximately 50-60 nm in diameter) in dilute salt-free and salt-c…
We report the theoretical investigations on the colossal magnetocaloric effect using a simple model that couples the lattice entropy and magnetic entropy through the magnetoelastic deformation. Analytical expressions were obtained for the thermodynamic magnetic state equation as well as for the total entropy and heat…
Novel thermoreversible physical hydrogels formed from polymers with linear and star architectures possessing a linear poly(ethyleneimine) (PEI) backbone have been investigated. The hydrogelation occurred simply upon natural cooling of hot aqueous solutions of PEIs to room temperature. The X-ray diffraction and differe…
One important step toward the understanding of the mechanisms of thermoelectric properties is the knowledge about local distortions and vacancy ordering in clathrates. The type-I clathrate Rb8Sn44 shows in single-crystal and powder diffraction patterns a 2 x 2 x 2 supercell of the primitive cubic unit cell (Pmn), whic…
The ultrafast relaxation dynamics of two rotation-restricted (azobenzeno-2S-phane and azobenzeno-4S-phane) and one rotation-free (4,4'-dimethylazobenzene) azobenzene derivatives were investigated using femtosecond fluorescence up-conversion on both S(1)(n,pi) and S(2)(pi,pi) excitations. On S(2) excitation, pulse-limi…
We report on atomic layer deposition of an ∼2-nm-thick ZnO layer on the inner surface of ultralow-density (∼0.5% of the full density) nanoporous silica aerogel monoliths with an extremely large effective aspect ratio of ∼105 (defined as the ratio of the monolith thickness to the average pore size). The resultant monol…
Lack of matrix dispersion is one principle reason why single-walled carbon nanotube (SWNT) composites have not yielded the enormous enhancement of mechanical properties predicted by theory. Non-destructive methods for gauging matrix dispersion, using near-IR fluorescence are reported (see Figure), along with new mater…
2,5-Diphenyl-1,4-distyrylbenzene with all cis double bonds shows strong fluorescence in crystal, which is due to the chemical processes, c.a. isomerization and photocyclization being limited by the lattice packing.
The realization of high-performance electrical devices incorporating single-wall carbon nanotubes critically depends on the minimization of charge transport barriers in the tubes and at the contacts. Herein we demonstrate photocurrent imaging as a fast and effective tool to locate such barriers within individual metal…