Materials Literature
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Highly ordered cobalt substituted MCM-41 samples were synthesized and characterized for application as catalytic templates for producing aligned single walled carbon nanotubes (SWNT). Highly reproducible Co−MCM-41 samples were successfully synthesized using alkyl templates with 10, 12, 14, 16, and 18 carbon chain leng…
A novel donor-acceptor bisphthalocyanine (bis-Pc, 1) in which two different Pc units (Zn(II)-Pc and Ni(II)-Pc) are linked via vinylene spacers to the pseudopara positions of a central [2.2]paracyclophane moiety is described. The synthesis of 1 is achieved by two successive Heck reactions of pseudopara-divinyl[2.2]para…
There is recently interests in the ``left-handed '' materials. In these materials the direction of the wave vector of electromagnetic radiation is opposite to the direction of the energy flow. We present simple arguments that suggests that magnetic composites can also be left-handed materials. However, the physics inv…
Organic monolayer-passivated Group III−V dilute magnetic semiconductor (DMS) Mn x In 1 - x As nanocrystals, ranging from 2.2 to 10 nm in diameter, were synthesized by high-temperature colloidal arrested precipitation using the dehalosilylation of InCl 3 and MnBr 2 with tristrimethylsilylarsine in the coordinating solv…
The effect of substrate surface energy on transcrystalline growth at the interface of a semicrystalline polymer and its effect on interfacial adhesion were investigated for substrates treated with various silane coupling agents. A thin film of isotactic polypropylene (iPP) crystallized on a high surface energy substra…
The magnetism of a series of tetranuclear complexes of the [Fe4IIL4]8+ [2x2]-grid-type was investigated, revealing the occurrence of spin transition behavior within this class of compounds. The phenomenon depends directly on the nature of the substituent R(1) in the 2-position on the central pyrimidine group of the li…
Soluble crosslinked macromolecules (microgels) used as stabilizers of catalytically active metal nanoclusters allow control of the nanocluster size by simply changing the crosslinking degree of the microgel. Microgel‐stabilized metal nanoclusters are easily prepared and stored in the solid state, and those of Pd (see…
We have studied the influence of alloying with a fourth element on the temperature of ferromagnetic ordering $T_C$ in Ni-Mn-Ga Heusler alloys. It is found that $T_C$ increases or decreases, depending on the substitution. The increase of $T_C$ is observed when Ni is substituted by either Fe or Co. On the contrary, the…
We report a new spin-injection effect found for a manganite using a specially fabricated sample. A wire of La0.7Sr0.3MnO3 was patterned by means of focused ion beam etching, and the central part was subsequently irradiated with Ga+ ions lightly. The ferromagnetic Curie temperature was reduced locally by the irradiatio…
We solve appropriate drift-diffusion and Landau-Lifshitz-Gilbert equations to demonstrate that unpolarized current flow from a non-magnet into a ferromagnet can produce a precession-type instability of the magnetization. The fundamental origin of the instability is the difference in conductivity between majority spins…
Recently, mechanical tests on ice as well as dislocation dynamics simulations have revealed that plastic flow displays a scale-free intermittent dynamics characterized by dislocation avalanches with a power law distribution of amplitudes. To further explore the complexity of dislocation dynamics during plastic flow, w…
A microcapillary flow reactor has been used to prepare a size series of colloidal CdSe nanocrystals (NCs). The continuous‐flow method (see Figure for schematic) produces samples with size distributions and quantum yields comparable to those prepared in conventional batch processes. The results obtained from the reacto…
Compounds based on the 4,4-difluoro-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacene (BODIPY) framework are excellent fluorescent markers. When BODIPY dyes of this type are conjugated to functionalities that absorb at relatively short wavelengths, those functionalities can, in some molecules, transmit the absorbed en…
Amphiphilic block copolymers in solution spontaneously self-assemble when the solvent quality for one block is selectively decreased. We demonstrate that, for supersaturation ratio changes [d(S)/dt] over 10(5) per second from equilibrium, nanoparticles are obtained with a formation mechanism and size dependent on the…
Femtosecond time-resolved transient absorption studies have been performed to investigate the photoinduced energy and electron-transfer processes in Zn(II)porphyrin-Zn(II)chlorin-fullerene triad in which energy and oxidation potential gradients are directed along the donor-acceptor-linked arrays. Fast energy transfer…
Rietveld analyses performed on high-temperature X-ray (HTXRD) and neutron (HTND) powder patterns of β-(Zr 2 O)(PO 4 ) 2 have allowed us to follow accurately the thermal variations of the cell parameters and to explain its strong dilatometric anisotropy in terms of structural distortions. It appeared that the anomaly r…
We have studied the storage and long-range transport of electrons in a porous assembly of weakly coupled ZnO quantum dots permeated with an aqueous and a propylene carbonate electrolyte solution. The number of electrons per ZnO quantum dot is controlled by the electrochemical potential of the assembly; the charge of t…
The present work presents LO and TO functions in the mid-infrared region for thin films deposited from glow discharge plasmas of tetramethylsilane (TMS) diluted either in Ar or O 2 or in mixtures of these two gases. These functions were calculated through the Kramers−Krönig analysis of transmittance spectra of the fil…
A new series of phthalocyanine-containing biodegradable poly(ε-caprolactone)s have been synthesized by ring-opening polymerization of ε-caprolactone and/or 5-ethylene ketal ε-caprolactone using silicon phthalocyanine dihydroxide as the initiator and tin(II) 2-ethylhexanoate as the catalyst. The polymers have been spec…
Abstract The imaging of the near field by a slab of negative permittivity medium is discussed. The performance of this flat lens is limited by the working wavenumber k 0 and the slab thickness d . For k 0 d ≪ 0.937, the resolution of the flat lens can be smaller than the wavelength and depends logarithmically on 1/ k…