Catalogue of satellite observations, no. C-24

Satellite observations by U.S. and foreign stations during 1960 as part of NASA progra

Hydrophilic (AB)n Segmented Copolymers for Melt Extrusion-Based Additive Manufacturing

Several manufacturing technologies beneficially involve processing from the melt, including extrusion‐based printing, electrospinning, and electrohydrodynamic jetting. In this study, (AB)$_{n}$ segmented copolymers are tailored for melt‐processing to form physically crosslinked hydrogels after swelling. The copolymers are composed of hydrophilic poly(ethylene glycol)‐based segments and hydrophobic bisurea segments, which form physical crosslinks via hydrogen bonds. The degree of polymerization was adjusted to match the melt viscosity to the different melt‐processing techniques. Using extrusion‐based printing, a width of approximately 260 µm is printed into 3D constructs, with excellent interlayer bonding at fiber junctions, due to hydrogen bonding between the layers. For melt electrospinning, much thinner fibers in the range of about 1–15 µm are obtained and produced in a typical nonwoven morphology. With melt electrowriting, fibers are deposited in a controlled way to well‐defined 3D constructs. In this case, multiple fiber layers fuse together enabling constructs with line width in the range of 70 to 160 µm. If exposed to water the printed constructs swell and form physically crosslinked hydrogels that slowly disintegrate, which is a feature for soluble inks within biofabrication strategies. In this context, cytotoxicity tests confirm the viability of cells and thus demonstrating biocompatibility of this class of copolymers

EEG im Sport: kortikale Aktivität im topographischen EEG durch sportliche Beanspruchung

Mechau D. EEG im Sport: kortikale Aktivität im topographischen EEG durch sportliche Beanspruchung. Forum Sportwissenschaft ; 6. Schorndorf: Hofmann; 2001

Inkjet Printed, High Mobility Inorganic-Oxide Field Effect Transistors Processed at Room Temperature

Printed electronics (PE) represents any electronic devices, components or circuits that can be processed using modern-day printing techniques. Field-effect transistors (FETs) and logics are being printed with intended applications requiring simple circuitry on large, flexible (e.g., polymer) substrates for low-cost and disposable electronics. Although organic materials have commonly been chosen for their easy printability and low temperature processability, high quality inorganic oxide-semiconductors are also being considered recently. The intrinsic mobility of the inorganic semiconductors are always by far superior than the organic ones; however, the commonly expressed reservations against the inorganic-based printed electronics are due to major issues, such as high processing temperatures and their incompatibility with solution-processing. Here we show a possibility to circumvent these difficulties and demonstrate a room-temperature processed and inkjet printed inorganic-oxide FET where the transistor channel is composed of an interconnected nanoparticle network and a solid polymer electrolyte serves as the dielectric. Even an extremely conservative estimation of the field-effect mobility of such a device yields a value of 0.8 cm2/(V s), which is still exceptionally large for a room temperature processed and printed transistor from inorganic materials

Ultraviolet photodetector arrays assembled by dielectrophoresis of ZnO nanoparticles

Sensitive and fast ultraviolet sensor arrays have been produced by dielectrophoretic assembling of ZnO nanoparticles. The sub-micron device dimensions induce low operating voltage and low power consumption. The devices are long-term stable and operate in air, oxygen and nitrogen. We have determined the absorption and desorption dynamics from the time-resolved photoresponse and conclude that oxygen or carbon dioxide are the photodesorbed species. We could derive the charge carrier concentration and mobility of the device from measurements of the low-bias and high-bias photocurrent. The presence of defects is discussed by comparing electroluminescence spectra from biased devices with photoluminescence spectral maps of ZnO dispersions