Materials Literature
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Equiatomic and near-equiatomic nickel-titanium alloys exhibit a shape-memory effect and superelasticity. However, the properties of such alloys are extremely sensitive to the precise nickel-titanium ratio and the addition of alloying elements. High corrosion resistance is necessary for biomedical applications, especia…
1H NMR, (13)C NMR, and EPR spectra of six-coordinate ferric porphyrin complexes [Fe(Por)L2]ClO4 with different porphyrin structures are presented, where porphyrins (Por) are planar 5,10,15,20-tetraphenylporphyrin (TPP), ruffled 5,10,15,20-tetraisopropylporphyrin (TiPrP), and saddled 2,3,7,8,12,13,17,18-octaethyl-5,10,…
Using a one-dimensional system, we demonstrate a wide variety of wave propagation phenomena possible in nonlinear left-handed media. These include effective second-harmonic generation where the fundamental wave and the second-harmonic wave are badly mismatched. We also observe parametric instabilities accompanying int…
We report on the growth of nominally undoped p-type ZnO films on Si(111) substrates by pulsed-laser deposition. Hall effect measurements show that the undoped ZnO films change from n-type to p-type material when the oxygen pressure changes from 6×10−5to3×10−4Torr during growth. Ti∕Au contacts produce ohmic behavior to…
Fine control of gold nanoparticle shape can be achieved by varying the pH of the reaction medium in the presence of gold nanorods, which acted as seeds. Under various pH (3.6–9.6) values of the reaction medium, different shapes of gold nanostructural architectures, from rectangle-, ‘dogbone’- and peanut-like outlines…
Three-dimensional quantitative structure−activity relationship (3D-QSAR) methods have been successfully applied in the field of drug design to search for a correlation between detailed molecular structure and bioactivity. Other areas, such as the development of single-site catalysts for homogeneous olefin polymerizati…
Keeping nature under control: The internal structure of helical porous protein mimics self-assembled from hybrid dendritic dipeptides is programmed by the stereochemistry of the dipeptide and regulated allosterically. This is the first example of a synthetic helical porous supramolecular structure that is stable both…
The interaction between self-aggregated porphyrins such as 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (TPPS) and 5,10,15,20-tetrakis(4-phosphonatophenyl)porphyrin (TPPP), and a generation 5 (G5) PAMAM dendrimer template is governed by minute differences of porphyrin acido-basic properties. While at neutral pH bot…
Chiral aggregation of oligo(p-phenylene vinylene)-functionalized Zn and free-base porphyrins is observed in water. The formation of mixed assemblies containing both porphyrins results in sequential energy transfer from OPV via zinc porphyrin to free-base porphyrin. Furthermore, the incorporation of C60 as electron acc…
Gates leading from cages: Linked paramagnetic cage complexes could potentially be used as quantum gates for quantum information processing. Experiments demonstrate that it is possible to link octanuclear {Cr7Ni} rings through both organic and metal–organic fragments into supramolecular dimers (see structure; Cr green,…
The crystallization kinetics of poly(l-lactide), PLLA, is slow enough to allow a quasi-amorphous polymer to be obtained at low temperature simply by quenching from the melt. The PLLA crystallization process was followed by differential scanning calorimetry and optical microscopy after nucleation isothermal treatments…
Oriented SWNTs in polymer composites have shown dramatic improvements in the physical properties of a composite because of the anisotropic shape and properties of SWNTs. Controlled alignment of SWNTs during composite fabrication implies better material function performance. This letter reports a new fabrication techni…
The C-F bond-forming step in the fluorinase, the only native fluorination enzyme characterized to date, has been studied. The enzyme catalyzes the reaction between S-adenosyl-L-methionine (SAM) and fluoride ions to form 5'-fluoro-5'-deoxyadenosine (5'-FDA) and L-methionine. To obtain an insight into the mechanism of t…
Optically driven actuators have been fabricated from single-wall carbon nanotube–polymer composite sheets. Like natural muscles, the millimetre-scale actuators are assemblies of millions of individual nanotube actuators processed into macroscopic length scales and bonded to an acrylic elastomer sheet to form an actuat…
A new method for controlling the hole density in single-walled carbon nanotube field-effect transistors (SWCNT-FETs) by solution-based chemical doping is presented. The use of organic molecules that adsorb onto SWCNTs from solution is investigated. The transfer characteristics of the SWCNT-FETs exhibit continuous and…
Single-crystalline CeOHCO 3 rods with an orthorhombic structure have been successfully synthesized by the sonochemical method from aqueous solution containing CeCl 3 and urea. Polycrystalline CeO 2 rods have been prepared by thermal conversion of single-crystalline CeOHCO 3 rods at 500 °C in air. CeOHCO 3 and CeO 2 ro…
The alpha- and beta-relaxation processes in amorphous indomethacin have been studied by using differential scanning calorimetry. The beta-process has been detected as a small endothermic peak that emerges before the glass transition step when reheating samples previously annealed in the temperature region -20 to +5 de…
We report a soft and template-free electrochemical deposition method for preparing wafer-scale ZnO nanoneedle arrays on an oriented gold film coated silicon substrate. It has been shown that the ZnO nanoneedles possess single-crystal wurtzite structure and grow along the c -axis perpendicularly on the substrate. Raman…
Split-ring resonators with a magnetic resonance in the near-infrared have been fabricated using the rapid- prototyping capabilities of focused- ion-beam writing. By varying the design parameters, a continuous transition from a degenerate Mie resonance to a magnetic-dipole response is shown (see Figure). In particular,…
Highly efficient organic UV photodetectors that are not sensitive to visible radiation (“visible-blind”) but to UV-A radiation are fabricated using an organic donor–acceptor couple. High external quantum efficiencies (EQEs) comparable to commercial GaN devices, but covering the entire UV-A range (see Figure), make the…