Physikingenieurwesen (PHY)
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A New Combined Optical and Robotic Testing System to Evaluate Multisegmental Spinal Kinematics
(2010)
The actuator pattern of an adaptive mirror determines the amplitudes and the fidelities of the mirror deformations that can be achieved. In this study, we analyze and compare different electrode patterns of piezoelectric unimorph deformable mirrors using a numerical finite element model. The analysis allows us to determine the optimum actuator pattern, and it is also applicable to bimorph mirrors. The model is verified by comparing its predictions with experimental results of our prototype of a novel unimorph deformable mirror.
Investigation of multisegmental spinal biomechanics with a combined optical and robotic test setup
(2010)
In this manuscript, a new approach in surface plasmon resonance microscopy is presented. The method provides optical real-time detection of single nanoparticles on surfaces. The potential of the method is demonstrated recording spherical dielectric particles as small as 40 nm in diameter and single HIV virus-like particles having diameters of similar to 100 nm both immobilized on functionalized surfaces. The surface plasmon resonance signal in the binding spots was found to be almost linearly proportional to the size of the particles and, therefore, surpasses the intensity of Mie scattering on spherical particle (dependence similar to r(-6)) by orders of magnitude for small objects. The physical reason leading to this strong effect is discussed.
The need for portable and on site screening methods for viruses is evident in face of virus infections that can spread lastly in a heavily connected world. A robust and efficient method for detecting viruses is a novel technique called Plasmon Assisted Microscopy of Nanoobjects. It is based on the acquisition of images from a sensor surface exploiting the behavior of surface plasmons in the presence of nanoobjects. In this paper an efficient image analysis approach with respect to the requirements of the sensor is presented and an embedded image processing system for this purpose is introduced. The processing pipeline comprises three steps and starts with restorating the images by removing the background and filtering artifacts. The acquired image series is analyzed pixel by pixel in a second pipeline step in order to detect pixels containing nanoobjects. In a last step pixels are aggregated to nanoobject structures. The paper introduces in the context of this virus detection method a configurable embedded system that was used for rapid prototyping of the image analysis algorithms in a flexible way. (C) 2010 Elsevier B.V. All rights reserved.
Over the past 5 years we have developed a new type of unimorph deformable mirror. The main advantages of this mirror technology are · very low surface scattering due to the use of superpolished glass · excellent coatings, even suitable for high power lasers, can be applied · active diameter of the mirrors can be between 10 mm and 100 mm · large strokes can be achieved even for small mirror diameters · integrated monolithic tip/tilt functionality based on a spiral arm design We have modeled these mirrors by analytical models as well as by the finite element method. This allows us to quickly design new mirrors tailored to specific applications. One example is a mirror for laser applications that has a diameter of 10 mm and can achieve a stroke in defocus mode of 5 μm. The stroke for these mirrors scales as the square of the mirror diameter, meaning that we can achieve, for example, a stroke of 125 μm for a mirror of 50 mm diameter. We will present design criteria and tradeoffs for these mirrors. We characterize our mirrors by the maximum stroke they can deliver for various Zernike modes, under the boundary condition that the Zernike mode has to be created with a certain fidelity, usually defined by the Maréchal criterion.