Lead-vapor filters for high-spectral-resolution temperature lidar

The analysis of Rayleigh-scattered laser radiation with atomic-vapor filters used for temperature measurements is investigated. The choices for the filter material and the optimum parameter configuration for daytime measurements are presented. In laboratory experiments the backscattered radiation from synthetic air stimulated by a cw dye laser at 283 nm was analyzed with two lead-vapor cells in one oven. The effects of different parameters on the accuracy of the measurement are determined from both theory and experiment, and actual air-temperature measurements are presented. Calculations for a real lidar show not only the performance, but also the limitations, of such a measurement system.     

Microwave Performance of AlGaN/GaN High-Electron-Mobility Transistors on Si/SiO2/Poly-SiC Substrates

The radiofrequency (RF) performance of AlGaN/GaN high-electron-mobility transistors (HEMTs) grown by molecular beam epitaxy (MBE) on Si-on-poly-SiC (SopSiC) substrates formed by the Smart-Cut^TM process is reported. This provides a low-cost, high-thermal-conductivity substrate for power applications. HEMTs with a 0.5 μm gate length show cutoff frequencies (f _T) of 18 to 27 GHz for gate-to-drain distances of 3 to 32 μm and a maximum frequency of oscillation (f _max) of 43 to 47 GHz. The f _max values are slightly lower than comparable devices on sapphire, SiC or Si alone. This approach looks promising for applications requiring cheap large-area substrates and better thermal management than provided by pure Si substrates alone.     

Zur Ermittlung des Energiebedarfs für Kunstlicht in Bürogebäuden – Diskussion von Meßresultaten

On determination of the electric lighting energy demand of non‐domestic buildings – discussion of measuring results Within the framework of a support programme “Energy Optimized Building” research und demonstration activities of energy‐saving non‐domestic buildings are supported since 1995. Amongst other publications two articles in this journa and a recently published book describe details on the support programme, the buildings and results. This paper deals with the evaluation of the use of daylight and electric lighting. Besides a comparison and results of the projects it focuses on the question how close to reality existing simulation or calculation tools predict the annual electric lighting energy demand.     

Chemical studies of CVD Cu deposited on Ta and TaN barriers under various process conditions

Contamination in the matrix of CVD copper films and at the interface between CVD copper films and barrier layers has been characterized using XPS, SIMS, XRD and RGA. Contamination in the CVD copper matrix has been found to increase with increasing precursor flow rate and with decreasing wafer temperature. Interfacial contamination has been investigated in an attempt to quantitatively define acceptable levels of contamination and ultimately reduce the effect of these contaminants on the integrated film stack. Sputtered copper flash layers for CVD copper deposition are also shown as highly effective for reducing the levels and effects of incorporated contamination.     

A CD14 domain with lipopolysaccharide-binding and -neutralizing activity

The interaction of lipopolysaccharide with CD14 plays a key role in signaling that activates an early defense against pathogens but also contributes to the development of sepsis and septic shock. Here we have mapped the entire 356-amino-acid protein with synthetic 20-amino-acid peptides and have identified a new lipopolysaccharide-binding domain with a strong LPS-neutralizing activity. Moreover, analysis of the structure-activity relationship of this peptide, which corresponds to amino acids 81-100 of human CD14, revealed that leucines 87, 91, and 94 are essential for these activities. The functional relevance of these residues was confirmed by cellular expression of mutant CD14 proteins that are no longer able to bind LPS. Furthermore, the peptide provided a basis for the generation of highly soluble analogues with stronger lipopolysaccharide-neutralizing activity.     

Optimized symbolic dynamics approach for the analysis of the respiratory pattern

Traditional time domain techniques of data analysis are often not sufficient to characterize the complex dynamics of respiration. In this paper, the respiratory pattern variability is analyzed using symbolic dynamics. A group of 20 patients on weaning trials from mechanical ventilation are studied at two different pressure support ventilation levels, in order to obtain respiratory volume signals with different variability. Time series of inspiratory time, expiratory time, breathing duration, fractional inspiratory time, tidal volume and mean inspiratory flow are analyzed. Two different symbol alphabets, with three and four symbols, are considered to characterize the respiratory pattern variability. Assessment of the method is made using the 40 respiratory volume signals classified using clinical criteria into two classes: low variability (LV) or high variability (HV). A discriminant analysis using single indexes from symbolic dynamics has been able to classify the respiratory volume signals with an out-of-sample accuracy of 100%.