Materials Literature
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Phase formation of surface alloying by spinodal decomposition has been studied at an electrified interface. For this aim Zn was electrodeposited on Au(111) from the ionic liquid AlCl(3)-MBIC (58:42) containing 1 mM Zn(II) at different potentials in the underpotential range corresponding to submonolayer up to monolayer…
We have realized highly efficient photodetectors based on composites of the semiconducting polymer poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene] and PbSe nanocrystal quantum dots. The external quantum efficiency in these devices is greater than 1 for electric fields E∼7×105V∕cm. The observed photocurrent…
Li2Pd3B is known to be superconducting, while the isotypical Li2Pt3B compound is not. Electronic structures of Li2Pd3B and Li2Pt3B have been calculated in order to obtain an insight into this surprising difference, through an analysis of the differences in the band structures. The electronic structures of these system…
Evidence for a strong spin-lattice coupling in multiferroic $\mathrm{Ho}\mathrm{Mn}{\mathrm{O}}_{3}$ is derived from thermal expansion measurements along the $a$ and $c$ axes. The magnetoelastic effect results in sizable anomalies of the thermal expansivities at the antiferromagnetic $({T}_{N})$ and the spin rotation…
Resistive transitions of an epitaxial Bi$_2$Sr$_2$CaCu$_2$O$_{8+δ}$ thin film were measured in various magnetic fields ($H\parallel c$), ranging from 0 to 22.0 T. Rounded curvatures of low resistivity tails are observed in Arrhenius plot and considered to relate to deviations from plastic barriers. In order to charact…
Prediction and characterization of crystal structures of alloys are a key problem in materials research. Using high-throughput ab initio calculations we explore the low-temperature phase diagrams for the following systems: {Bi-In, Bi-Mg, Bi-Sb, In-Mg, In-Sb, and Mg-Sb}. For the experimentally observed phases in these…
Carbon nanotubes have interesting electromechanical properties that may enable a new class of nanoscale mechanical sensors. We fabricated two-terminal nanotube devices on silicon nitride membranes, measured their electronic transport versus strain, and estimated their band gaps and the strain-induced changes in them.…
We report the synthesis of a single-walled carbon nanotube (SWNT) graft copolymer. This polymer was prepared by the functionalization of SWNTs with polyethyleneimine (PEI). We used this graft copolymer, SWNT-PEI, as a substrate for cultured neurons and found that it promotes neurite outgrowth and branching.
We predict the occurrence of large ferroelectric polarization and piezoelectricity in the hypothetical perovskite-structure oxides, bismuth aluminate (BiAlO 3 ) and bismuth gallate (BiGaO 3 ), using density functional theory within the local density approximation. We show that BiGaO 3 will have a similar structure to…
We report a chemical processing technology that allows the continuous spinning of single-walled carbon nanotubes (SWNTs)-nylon 6 (PA6) fibers by the in-situ polymerization of caprolactam in the presence of SWNTs, which simultaneously optimizes the morphology of the composite. We show that caprolactam is an excellent s…
Flexible polyurethane foam is often molded directly into preheated tools for foaming reaction which expands to fill the mold cavity. The foam that is directly in contact with the mold surface cures as the foam skin. Parts frequently have surface defects ranging from shrink marks, to voids, to mottling, and knit lines.…
We describe a new damage testing approach and instrumentation that provides quantitative measurements of bulk damage versus fluence for several frequencies. A major advantage of this method is that it can simultaneously provide direct information on pinpoint density and size, and beam obscuration. This allows for more…
Abstract As a result of a systematic analysis of the compilation of McMaster's x‐ray cross‐sections, the polynomial coefficients of the N range (from edges N 7 to M 5 ) of elements Z = 61–69 have to be corrected. Furthermore, no detailed information on position and jumps of M edges of elements Z > 53 and N edges of…
Aggregation abgeblockt: Triblock-Copolymere bestehend aus einem zentralen Polypeptidblock aus repetitiven [(AlaGly)3GluGly]n-Sequenzen mit β-Faltblattstruktur und Polyethylenglycol (PEG) von Mn=750 g mol−1 wurden synthetisiert und auf ihre Aggregationseigenschaften untersucht. Das Anbringen der PEG-Komponente verhinde…
Nucleation by chiral polyimide surfaces leads to finite enantioselectivity in the B4 phase of achiral banana mesogen molecules (see optical micrograph). An ee value of 10 % was obtained with rubbed chiral polyimide surfaces. This technique opens up new possible ways of controlling chirality in chemical and biological…
A retro-Diels–Alder reaction of a β-bicyclo[2.2.2]octadiene-fused precursor yields the doubly N-fused β-benzo[28]hexaphyrin(1.1.1.1.1.1) shown, which undergoes oxidative rearrangement upon treatment with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) to yield a macrocycle that emits fluorescence in the visible/near-I…
The effects of zeolites 4A, 13X, mordenite, and ZSM-5 on the thermal degradation and charring of intumescent ammonium polyphosphate (APP)–pentaerythritol (PER) systems were explored by X-ray photoelectron spectroscopy (XPS) and thermal gravimetric analyses (TGA). The weight loss rate of the third main degradation step…
The direct extrusion foaming process of low-density polypropylene (PP) in a typical single-screw extruder is researched. Effects of five variables on the volume expansion behavior and cellular morphologies are investigated. They are three kinds of polypropylene with different melt flow rates (MFRs), two kinds of chemi…
Compressive properties and failure analysis of unidirectional and plain weave S2-glass/vinylester composites under high strain rate (HSR) loading have been investigated using the Split Hopkinson Pressure Bar (SHPB) technique. A systematic experimental approach has been adopted in this work to identify the damage progr…
The generation of nanosized features via the bottom-up organization of individual atoms and molecules represents one of the most rapidly emerging fields in modern science and technology. In order to gain general and modular access to nanostructures, a construction kit consisting of molecular building blocks with defin…