Nanoimprint lithography for high-efficiency thin-film silicon solar cells

We demonstrate high-efficiency thin-film silicon solar cells with transparent nanotextured front electrodes fabricated via ultraviolet nanoimprint lithography on glass substrates. By replicating the morphology of state-of-the-art nanotextured zinc oxide front electrodes known for their exceptional light trapping properties, conversion efficiencies of up to 12.0% are achieved for micromorph tandem junction cells. Excellent light incoupling results in a remarkable summed short-circuit current density of 25.9 mA/cm(2) for amorphous top cell and microcrystalline bottom cell thicknesses of only 250 and 1100 nm, respectively. As efforts to maximize light harvesting continue, our study validates nanoimprinting as a versatile tool to investigate nanophotonic effects of a large variety of nanostructures directly on device performance.     

Toward Next-Gen Mobile AR Games

Mobile augmented reality games offer a new and rich game experience allowing players to move and interact in their physical environment with 3D content. The authors review existing approaches to mobile AR games and identify two major trends: small, user-modifiable AR games and larger-scale, event-based AR games that are interwoven with their physical environment.     

Zur Geschichte der Eisengewinnung mit Holzkohle und Steinkohlenkoks

Iron, which gave the impulse to the age of machines and industry, still represents the most important and mostly utilized raw material. Concerning this, a large amount of literature exists but not much about its history within human culture. For that reason, we try to demonstrate the importance of this metal for technical purposes and the life of mankind by reviewing the centuries from prehistory up to modern times. With regard to the production of iron the substitution of charcoal by coal coke was of very great importance, and the life-work of the family Darby essentially participated in this invention. Their pioneering minds and creative energy helped the iron industry to a remarkable rise, which eventually introduced the Industrial Revolution.      

Betriebsleitsysteme zur Rezepturverwaltung und Produktionsdatenverarbeitung

Plant control systems for administration of formulations and processing of production data. Hitherto, support from electronic data processing in a company was generally on the managerial level and benefitted the commercial/administrative tasks occurring there. On the other hand, automation of production has been accelerated by the increasing use of digital systems such as stored program systems, process controllers, electronic data acquisition devices, and laboratory automation and information management systems. However, there was a gap between the two which is now beginning to close since the introduction of plant control systems. The tasks of these systems lie in process-proximate balance, quality assurance, production overviews, formulation procedures, and optimum plant control. The benefit of such plant management systems lies in the accessibility of up-to-date information to all qualified persons involved in plant management.     

Independently controlled EMG responses in treadmill locomotion by cats

Cats were trained to walk and trot on a motor-driven treadmill such that mean kinematic timings were highly uniform. Evidence was sought that variations in electromyographic activity in individual muscles was due to separate sources of control. EMGs were recorded on magnetic tape from a knee extensor, vastus lateralis (VL), and a hip flexor, iliopsoas (IP). At the same time, the cat's movements were recorded on 16 mm cine film at 100 frames per sec. In accordance with previous reports, VL showed one long main burst during the stance (down) portion of the step cycle. However, there were two onset times. A late swing (foot up) component began a few msec before touchdown in every stride in every cat. In contrast, in some cats an earlier burst, that was not completely continuous with the main burst, began 50-100 msec before touchdown and was present in most but not all individual strides. In a few animals there was also an occasional burst in mid-swing. The stance burst itself was further subdivided into multiple peaks that presumably were at least partly reflexive responses to pressure from the belt. The flexor, IP, also showed multiple peaks in its long main burst and other activity whose presence varied from cat to cat. It was concluded that the independence of control for many EMG components during locomotion requires a behavioral analysis of reflexes and conditioned responses to determine the origin of each kind of activity.     

Design and analysis of a content-based pathology image retrieval system

A prototype, content-based image retrieval system has been built employing a client/server architecture to access supercomputing power from the physician's desktop. The system retrieves images and their associated annotations from a networked microscopic pathology image database based on content similarity to user supplied query images. Similarity is evaluated based on four image feature types: color histogram, image texture, Fourier coefficients, and wavelet coefficients, using the vector dot product as a distance metric. Current retrieval accuracy varies across pathological categories depending on the number of available training samples and the effectiveness of the feature set. The distance measure of the search algorithm was validated by agglomerative cluster analysis in light of the medical domain knowledge. Results show a correlation between pathological significance and the image document distance value generated by the computer algorithm. This correlation agrees with observed visual similarity. This validation method has an advantage over traditional statistical evaluation methods when sample size is small and where domain knowledge is important. A multi-dimensional scaling analysis shows a low dimensionality nature of the embedded space for the current test set.     

Active star coupler based fiber-optic local area network

A 50-MBd active star fiber optical Iocal area network (LAN) and its optical combiner and mixing rod splitter are presented. The limited power budget and relatively large tapping losses of lightwave technology, which limit the use of fiber optics in tapped bus LAn topologies, are examined and proven tolerable in optical star topologies. The optical combiner and splitter, compononets necessary for such a network, have been fabricated and evaluated. The optical combiner, consisting, of a fiber bundle couled to a large-area p-i-n photodetector, and the mixing rod splitter, which had an insertion lodd of 19.8dB±1.4dB (including splitting loss), are shown to have suitable characteristics for the 50-MBd 32-node active optical star network. This star topology. proposed as an internetwork gateway which uses token-passing or polling protocol for packet switched data transmission, could be enhanced with wavelength-division multiplexing to provide both packet switched data and frequency division circuit switched real-time video and voice services network. Applications suggested for such a gateway or netwrok include health car information systems and factory automation.