Flachdisplays auf der Basis aufgedampfter organischer Leuchtdioden. Flat Panel Displays based an vacuum sublimed organic light emitting diodes

Light emitting diodes based an organic semiconductors (OLEDs) have properties which make them well suited for the use in flat panel display systems. Some applications like a car stereo display and mobile phone displays are already an the market. Nevertheless, there is still a huge demand for optimization, especially in terms of operating voltage and efficiency. By the use of intentionally doped charge carrier transport layers in such OLEDs, the lowest reported operating voltages could be recently achieved at the Institut für Angewandte Photophysik at the Technical University of Dresden. They are around 2.5V for a typical monitor brightness of 100cd/m². Also in Dresden, at the Fraunhofer Institute for microelectronic circuits and systems, a new production technology for flat panel displays based an OLEDs will be tested in the future. This consists of an In‐Line vacuum system with a highly efficient materials use and a high throughput.     

Millimeter-wave design considerations for power amplifiers in an SiGe process technology

This paper describes a number of significant modeling considerations for SiGe heterojunction bipolar transistor power amplifiers operating at millimeter-wave frequencies. Small- and large-signal model-to-hardware correlation is presented for single transistor amplifiers, as well as for a combined dual-stage amplifier up to 65 GHz. The relevant parasitic effects are described along with the proposed modeling approach for each of them. The limits of the standard Vertical Bipolar Inter-Company device model at high-injection and their effect on the prediction of the achievable large-signal compression and power-added efficiency are also discussed.     

Determination of the complex permittivity of packaging materials at millimeter-wave frequencies

The focus of this paper is the determination of the complex permittivity of chip packaging materials at millimeter-wave frequencies. After a broad overview of existing measurement techniques, three methods will be presented that have been established for the dielectric property determination of substrate, as well as mold materials (encapsulants, under-fill, etc.) in the millimeter-wave frequency range. First, the open resonator used here will be briefly described. It allows accurate determination of the dielectric constant and loss of thin sheet substrate materials from below 20 GHz to above 100 GHz. Second, a filled waveguide method is explained in detail. The setup used here can determine the complex dielectric properties of mold materials from 70 to 100 GHz. Third, the method based on covered transmission lines will be described in detail. The used lines allow measurements from below 40 GHz to approximately 90 GHz. Verification of all three methods will be provided by inter-comparison and comparison to values from the literature. Additionally, results for several typical substrate and mold materials that are available for millimeter-wave packaging will be shown and discussed.     

THz Direct Detector and Heterodyne Receiver Arrays in Silicon Nanoscale Technologies

Journal of Infrared, Millimeter, and Terahertz Waves - The main scope of this paper is to address various implementation aspects of THz detector arrays in the nanoscale silicon technologies...     

A protocol to evaluate semi-rigid pedicle screw systems

The objective of the current study was to develop an in vitro testing protocol to evaluate semi-rigid pedicle screw devices. A corpectomy model protocol exists to evaluate rigid spinal implants; however, semi-rigid devices are contraindicated for this condition. This paper describes a technique that simulates more closely the conditions a semi-rigid device would see in vivo. Finally, the new testing protocol is used to evaluate the DDS pedicle screw-cable system. Benefits and shortcomings of the new protocol are discussed.     

Directional reflectance properties determined by analysis of airborne multispectral scanner data and atmospheric correction

Directional reflectance properties of natural surfaces are very important in the interpretation of remotely sensed data. The analysis of multispectral scanner data shows a distinct dependence on scan angle, wavelength (0.4–1.1 μm), and classes (e.g., bare soil, vegetation). This relationship can be described by polynomials determined by regression methods. Atmospheric effects are computed with a simple model by parametrization of the multiple scattered skylight. The model permits a quick and sufficient estimation of the airlight, depending on the data collection conditions. Comparisons of the scanner data with the corresponding model yield the following results: The differences between airborne and ground measurements are due to atmospheric effects. The directional variation in brightness is mainly caused by the object itself with the exception of short wavelengths and/or a very low albedo. The hue shift of vegetation is essentially produced by the object and modified by the atmosphere. Taking into account the directional reflectance properties in a direction-dependent classification procedure results in an improvement of up to 20% in comparison with algorithms used so far. Quantitative relationships between ground measurements and radiation measurements by airborne sensors including atmospheric effects can be determined with the proposed methods.     

Influence of transportation stress and animal temperament on fecal shedding of Escherichia coli O157:H7 in feedlot cattle

To test the influence of transportation stress and temperament on shedding of Escherichia coli O157:H7, cattle (n=150) were classified at various stages of production as Excitable, Intermediate or Calm based on a variety of disposition scores. Presence of E. coli O157:H7 was determined by rectal swabs from live animals and from colons collected postmortem. Percentage of cattle shedding E. coli O157:H7 at arrival at the feedlot was approximately equal among temperament groups. Before shipment to the processing facility, a higher (P=0.03) proportion of cattle from the Calm group shed E. coli O157:H7 compared to the other temperament groups. When pooled across all sampling periods, cattle from the Calm group had a greater percentage test positive for E. coli O157:H7. Neither the acute stressor of transportation nor a more excitable temperament led to increased shedding of E. coli O157:H7 in cattle.     

Interrelation between crystal packing and small-molecule organic solar cell performance

X-ray investigations on single crystals of a series of terminally dicyanovinyl-substituted quaterthiophenes and co-evaporated blend layers with C(60) give insight into molecular packing behavior and morphology, which are crucial parameters in the field of organic electronics. Structural characteristics on various levels and length scales are correlated with the photovoltaic performance of bulk heterojunction small-molecule organic solar cells.