In this Letter, the effect of CO2 contamination on nonaqueous Li–O2 battery rechargeability is explored. Although CO2 contamination was found to increase the cell’s discharge capacity, it also ...spontaneously reacts with Li2O2 (the primary discharge product of a nonaqueous Li–O2 battery) to form Li2CO3. CO2 evolution from Li2CO3 during battery charging was found to occur only at very high potentials (>4 V) compared to O2 evolution from Li2O2 (∼3–3.5 V), and as a result, the presence of CO2 during discharge dramatically reduced the voltaic efficiency of the discharge–charge cycle. These results emphasize the importance of not only completely removing CO2 from air fed to a Li-air battery, but also developing stable cathodes and electrolytes that will not decompose during battery operation to form carbonate deposits.
The development of nanoscale electronic and photonic devices will require a combination of the high throughput of lithographic patterning and the high resolution and chemical precision afforded by ...self-assembly. However, the incorporation of nanomaterials with dimensions of less than 10 nm into functional devices has been hindered by the disparity between their size and the 100 nm feature sizes that can be routinely generated by lithography. Biomolecules offer a bridge between the two size regimes, with sub-10 nm dimensions, synthetic flexibility and a capability for self-recognition. Here, we report the directed assembly of 5-nm gold particles into large-area, spatially ordered, two-dimensional arrays through the site-selective deposition of mesoscopic DNA origami onto lithographically patterned substrates and the precise binding of gold nanocrystals to each DNA structure. We show organization with registry both within an individual DNA template and between components on neighbouring DNA origami, expanding the generality of this method towards many types of patterns and sizes.
Artificial DNA nanostructures show promise for the organization of functional materials to create nanoelectronic or nano-optical devices. DNA origami, in which a long single strand of DNA is folded ...into a shape using shorter 'staple strands', can display 6-nm-resolution patterns of binding sites, in principle allowing complex arrangements of carbon nanotubes, silicon nanowires, or quantum dots. However, DNA origami are synthesized in solution and uncontrolled deposition results in random arrangements; this makes it difficult to measure the properties of attached nanodevices or to integrate them with conventionally fabricated microcircuitry. Here we describe the use of electron-beam lithography and dry oxidative etching to create DNA origami-shaped binding sites on technologically useful materials, such as SiO(2) and diamond-like carbon. In buffer with approximately 100 mM MgCl(2), DNA origami bind with high selectivity and good orientation: 70-95% of sites have individual origami aligned with an angular dispersion (+/-1 s.d.) as low as +/-10 degrees (on diamond-like carbon) or +/-20 degrees (on SiO(2)).
Wallraff and Hinsberg provide an overview of the issues to be considered for patterning in the sub-100 nm regime and describe the imaging technologies that are currently being evaluated for such use.
We have synthesized a series of diphenylamine-substituted coumarin, (dicyanomethylene)pyran, and benzophenoxazone dyes and report on their optical and electroluminescent properties, thermal and ...photooxidative stabilities, and potential as red and green dopants for organic light-emitting diode (OLED) displays or down-conversion fluorescent dyes for external color-converters. Incorporation of the bulky phenyl groups in these dyes delays the onset of concentration quenching when they are dissolved in polymer films. Their improved photoluminescent efficiency and photooxidative stability make them excellent candidates for external color-conversion. The improved electroluminescence and power efficiencies and enhanced thermal stability of 3-(2‘-benzimidazolyl)-7-(diphenylamino)-2H-1-benzopyran-2-one (C7S) as well as its Commission Internationale d'Eclairage (CIE) coordinates suggests its use as a green dopant in OLED devices.
Chemically amplified (CA) resists are in widespread use for the fabrication of leading-edge microelectronic devices, and it is anticipated that they will see use well into the future. The refinement ...and optimization of these materials to allow routine imaging at dimensions that will utlimately approach the molecular scale will depend on an improved in-depth understanding of the materials and their processing.
Kodex und Kanon Wallraff, Martin
2013, 2013-03-01, Letnik:
12
eBook
Christentum und Buch - das ist mehr als eine oberflächliche Beziehung. Die Geschichte beider ist etwa gleich alt: Der Aufstieg des Christentums und die Durchsetzung des Kodex erfolgten in der ...Spätantike. Es gibt auch inhaltliche Bezüge, machte sich doch das Christentum das neue Medium früh zunutze - und das Medium hatte seinerseits Rückwirkungen auf die Religion. Die christlich-antike Buchkultur bildet zudem die Voraussetzung für die Schriftwerdung des Korans.
PDF
