Materials Literature
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Desorption/ionization on porous silicon mass spectrometry (DIOS-MS) is a novel method for generating and analyzing gas-phase ions that employs direct laser vaporization. The structure and physicochemical properties of the porous silicon surfaces are crucial to DIOS-MS performance and are controlled by the selection of…
Photoluminescence (PL) from surface-oxidized Si nanocrystals (nc-Si) was studied as a function of the size. The size of nc-Si was comparable with or larger than the Bohr radius of free excitons in bulk Si crystal (5 nm). In contrast to smaller surface-oxidized nc-Si (typically as small as a few nanometers in diameter)…
The existing theories which aim to explain the extraordinary optical transmission of a metallic film pierced by a two-dimensional subwavelength hole array [T.W. Ebbesen, H.J. Lezec, H.F. Ghaemi, T. Thio, and P.A. Wolff, Natural (London) 391, 667 (1998)] all have in common the following feature: instead of studying the…
The structure of laser-crystallized thin films of Ge2Sb2+xTe5 (0.0<x⩽1.0) formed by the sputtering method were identified by x-ray diffraction studies to be composed of two phases: one phase is chiefly NaCl type crystal with a lattice constant of about 6 Å and a composition corresponding to Ge2Sb2Te5; the other…
We present results on the photoluminescence (PL) properties of silicon nanocrystals as a function of their size. The nanocrystals are synthesized by laser pyrolysis of silane in a gas flow reactor and deposited at low energy on a substrate after a mechanical velocity and size selection. Both the photoluminescence spec…
The tumor drug concentrations, drug distributions, and therapeutic efficacies achieved by three fundamentally different liposomes, nonthermosensitive liposome (NTSL), traditional thermosensitive liposome (TTSL), and low temperature sensitive liposome (LTSL); free doxorubicin (DOX); and saline in combination with hyper…
The so-called local-density approximation (LDA) plus the multiorbital mean-field Hubbard model (LDA+U) has been implemented within the all-electron projector augmented-wave method, and then used to compute the insulating antiferromagnetic ground state of NiO and its optical properties. The electronic and optical prope…
We show that elastomeric surfaces can be tailored using "mechanically assembled monolayers" (MAMs), structures that are fabricated by combining self-assembly of surface grafting molecules with mechanical manipulation of the grafting points in the underlying elastic surface. The versatility of this surface modification…
During the last decade, fuel cells have received enormous attention from research institutions and companies as novel electrical energy conversion systems. In the near future, they will see application in automotive propulsion, distributed power generation, and in low power portable devices (battery replacement). This…
We show a simple, robust, chemical route to the fabrication of ultrahigh-density arrays of nanopores with high aspect ratios using the equilibrium self-assembled morphology of asymmetric diblock copolymers. The dimensions and lateral density of the array are determined by segmental interactions and the copolymer molec…
Systematic studies of trisiloxane surfactant aqueous solutions spreading over hydrophobic liquids are performed by videomicroscopy. Three trisiloxane nonionic surfactants M(D‘E n )M with different ethoxy-chain lengths are investigated. In addition to surfactant concentration, the spreading rate strongly depends on sur…
The π-connectivity of a bis(semiquinone) ligand enforces ferromagnetic coupling between the two semiquinone halves of the molecule. Using the ligand in connection with paramagnetic metal ions leads to complexes with S = 3 (M = NiII), S = 2 (M = CuII), and S = 2 (M = CrIII) ground states.
The effect of increasing chain length on the excited-state properties of two series of covalently linked zinc porphyrin oligomers has been investigated. One series has a 1,4-phenylene bridge, (PB) n with n = 1, 2, 3, and 5, and the other series has a 1,4-butadiynylene bridge, (yPy) n with n = 1−6. The two series diffe…
The local structure of the relaxor single crystal PMN has been studied via a measurement of the temperature dependences of the ${}^{207}\mathrm{Pb}$ spectra and relaxation times between 450 K and 15 K. The ${}^{207}\mathrm{Pb}$ NMR spectra are frequency distributions which reflect the existence of polar nanoclusters a…
Using a laser monitoring observation technique, the solubilities of terephthalaldehydic acid, p -toluic acid, benzoic acid, terephthalic acid, and isophthalic acid in N -methyl-2-pyrrolidone were determined by the synthetic method from (295.65 to 371.35) K. The experimental results were correlated by an empirical equa…
Slit-width-controlled H 2 Ti 4 O 9 /TiO 2 nanocomposites were fabricated by stirring with (C n H 2 n +1 NH 3 ) 2 Ti 4 O 9 and a titanyl acylate complex at 20 °C for 48 h followed by UV light irradiation from a 450 W high-pressure mercury lamp. (C n H 2 n +1 NH 3 ) 2 Ti 4 O 9 was synthesized by an intercalation reactio…
A new approach for preparation of highly branched copolymers from A 2, B 2, and BB‘ 2 type monomers was reported in this work. Highly branched copoly(sulfone−amine)s were synthesized by polyaddition of piperazine (B 2 ) and 1-(2-aminoethyl)piperazine (BB‘ 2 ) to divinyl sulfone (A 2 ). The polymerization mechanism was…
The surfaces of the gamma and eta forms of alumina are well known to differ significantly in Lewis acidity. Surface reconstructions observed on gamma- and eta-alumina are also qualitatively different, despite the close similarity of the bulk structures. Here we demonstrate through first-principles calculations that su…
Thirty‐four benthic diatom strains were isolated from thalassic hypersaline marine environments and their salinity tolerance characterized in growth experiments conducted at salinities ranging from 0.5% to 17.5% (weight of total salts per volume, g·100 mL − 1 ). The results were compared with the patterns of diatom sp…
Using dc magnetization, ac susceptibility, specific heat, and neutron diffraction, we have studied the magnetic properties of Mn[N(CN)2]2(pyz) (pyz = pyrazine) in detail. The material crystallizes in the monoclinic space group P2(1)/n with a = 7.3248(2), b = 16.7369(4), and c = 8.7905 (2) A, beta = 89.596 (2) degrees,…