The motion machine of Samuel Theodor Quellmalz

In 1735 the physician Samuel Theodor Quellmalz invented a machine which imitated the movements of a horse and was designed for medical treatment as well as general fitness. The invention paradigmaticlly characterizes the dominant medical discourse of that time and demonstrates a new confidence in technical innovations     

Factors affecting motion integration

The perceived direction of motion of a featureless contour inside a circular aperture is always perpendicular to the contour's orientation, regardless of its true motion (the aperture problem). This study investigates the circumstances under which unambiguous feature motion (of line terminators, single dots, or truncations of a D6 pattern) in adjacent apertures can alter the perceived direction of such featureless contours. We find that integration mechanisms responsible for motion capture are fairly robust against misorientations and contrast manipulations of individual components, are sensitive to differences in spatial frequencies, and scale with pattern size. Motion capture is not diminished when a D6 profile is substituted for the square-pulse profile of a line and is independent of the visibility of the apertures, indicating that object interpretations and three-dimensional analyses of a scene are less important than has been postulated previously. These results have strong implications for the neuronal hardware underlying the integration of motion signals across space and provide a framework for global motion models.     

Sensors and control concept of a biped robot

The biped robot "Johnnie" is designed to achieve a dynamically stable gait pattern, allowing for high walking velocities. Very accurate and fast sensors were developed for the machine. In particular, the design of the three-dimensional-orientation sensor and the six-axes force-torque sensor are presented. The control scheme is based on the information from these sensors to deal with unstructured terrain and disturbances. Two different implementations are investigated: a computed torque approach and a trajectory control with adaptive trajectories. Walking speeds of 2.4 km/h have been achieved in experiments.     

Catalytic combustion technology to achieve ultra low NOx, emissions: Catalyst design and performance characteristics

A catalytic combustion system has been developed which feeds full fuel and air to the catalyst but avoids exposure of the catalyst to the high temperatures responsible for deactivation and thermal shock fracture of the supporting substrate. The combustion process is initiated by the catalyst and is completed by homogeneous combustion in the post catalyst region where the highest temperatures are obtained. Catalysts have been demonstrated that operate at inlet temperatures as low as 320°C at 11 atm total pressure and conditions typical of high performance industrial gas turbines. The ignition temperature is shown to correlate with the specific catalytic activity of the washcoat layer over a rather broad range of activities. A reaction model has been developed that can predict ignition behavior from the measured catalytic activity.     

Skin susceptibility to dithranol: contact allergy or irritation?

Thrombomodulin (TM), a marker of endothelial cell damage, has been localized to the placental syncytiotrophoblast. A prospective cohort study of twenty-five pregnant women who were admitted with a clinical diagnosis of placental abruption was undertaken. Abruption was confirmed after delivery in eight cases (Group 1). Group 2 consisted of seventeen patients with no clinical or pathologic evidence of placental abruption after delivery. TM was significantly elevated in Group 1 (71.59+/-5.35 vs. 48.29+/-3.53 ng/ml, p = 0.001). The sensitivity and specificity of TM > or =60 ng/ml as a marker for abruption was 87.5 and 76.5%, respectively. In comparison, the sensitivity of an abnormal coagulation profile, maternal Kleihauer-Betke and ultrasound in patients with abruption was 0, 16.7 and 28.6%, respectively. TM is a highly sensitive and specific marker for acute placental abruption.     

Electro-optic near-field mapping of planar resonators

A comprehensive experimental and theoretical study for the determination of the electric near-field above planar resonators is presented. The transverse component of the electric field is mapped by external electro-optic (EO) sampling technique with high spatial and temporal resolution. The evolution of the near-field radiation pattern of the investigated 7-GHz planar resonator to the onset of the far-field pattern is traced by measurements at various heights above the sample. Frequency-dependent measurements allow to characterize the field pattern changes when the frequency is swept through the main resonance. Additional undesired resonances are identified by the detected mode pattern. The experimental data are reproduced by simulations based upon an electric field integral equation (EFIE) method     

GaAs-based four-channel photonic crystal quantum dot laser module operating at 1.3 /spl mu/m

A GaAs-based laser module, which combines the output of four singlemode lasers operating at 1.3 /spl mu/m by using photonic crystal mirrors and combiners, has been developed. The complete device size is around 0.2 mm/sup 2/. The lasers can be operated individually or in parallel with sidemode suppression ratios better than 20 dB.     

All-Optoelectronic Terahertz Imaging Systems and Examples of Their Application

We give an overview over several all-optoelectronic measurement systems which we have developed for transmittive and reflective imaging in the terahertz (THz) frequency range. The systems employ either pulsed or continuous-wave THz radiation. In both cases, they work on the basis of single-pixel scanning. Addressing the potential for imaging in the medical and dental field, and the application of THz radiation for industrial surface and interface characterization, we explore dark-field imaging where the imaging contrast originates from diffraction and scattering effects coming from topography or refractive-index variations.