Papers by Keyword: Imaging

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Authors: Futoshi Okayama, Michio Tajima, Hiroyuki Toyota, Atsushi Ogura
Abstract: We demonstrated high-speed imaging of photoluminescence (PL) and electroluminescence (EL) for not only band-to-band but also multiple deep-level emissions in a multicrystalline Si solar cell. We used a cooled InGaAs camera with a photosensitive range of 900 - 1700 nm equipped with band-pass filters for the selective detection of various deep-level emissions. The exposure time for imaging was only 1 - 10 seconds. Comparisons of the present PL images with the microscopic PL mappings confirmed for us that essentially the same luminescence patterns were obtained.
Authors: Xin Jie Zhu, Zan Dong Han, Dong Du, Yi Fang Chen, Ke Yi Yuan
Abstract: The imaging and testing of ultrasonic SH (Shear Horizontal) guided waves may be used into testing and SHM (Structure Health Monitoring) of industrial plate with welding structure in service, which have much more important applied potential. During imaging and testing for steel plate with lap welding structure, photoelastic experiment on propagation of guided waves in Plexiglas plate was studied to clearly see the excellent advantages of SH guided waves. The mode of SH guided waves was analyzed to select the zero order mode SH0 and the SH guided waves transducer with SH0 mode was developed. Based on the synthetic aperture focusing method,a multichannel ultrasonic imaging and testing experimental system of ultrasonic SH guided waves was constructed,the imaging of plate with lap welding structure was mainly studied. The research results shows the ultrasonic SH guided waves and the transducers are fit for long distance testing for the plate with lap welding structure. The ultrasound scattering nearby the weld may cause a blind testing zone, about 150 mm wide, in which the less size corrosion defects at the blind zone could not be revealed in image, so as to lead to defects “no testing”. The imaging and testing of ultrasonic SH guided waves would be used for non-destructive testing of plate with lap welding structure, which image both can characterize the corrosion defects and lap welding structure, and realize the precise location of the weld. The proposed research provides important foundation for improving ultrasonic guided waves imaging and testing quality and SHM of industrial in-site plate with lap welding and larger size.
Authors: Chun H. Wang, L.R. Francis Rose
Abstract: Existing damage imaging techniques rely on the use of active sensors, such as piezoelectric actuators, that can both transmit and receive guided waves. This paper presents a new time-reversal imaging approach to enable the use of passive sensors, such as optical fibre sensors and strain gauges, to augment active sensors for imaging structural damage. Computational simulations have revealed that damage size and severity can be accurately determined from the scattered wave using as few as six sensors: one active sensor and five passive sensors.
Authors: Patrick Berwian, Daniel Kaminzky, Katharina Rosshirt, Birgit Kallinger, Jochen Friedrich, Steffen Oppel, Adrian Schneider, Michael Schütz
Abstract: A new tool for characterizing extended defects in Silicon Carbide (SiC) based on photoluminescence imaging is presented. In contrast to other techniques like Defect Selective Etching (DSE) or X-ray topography this technique is both fast and non-destructive. It is shown that several defect types, especially those relevant for the performance of electronic devices on SiC (i.e. Stacking Faults and Basal Plane Dislocations) can be investigated. The tool is therefore usable in research and development for a quick feedback on process related defect generation as well as in a production environment for quality control.
Authors: Martin Veidt, C.T. Ng, S. Hames, Thomas Wattinger
Abstract: This paper presents the application of Lamb waves to detect and locate laminar damages using a beam forming imaging methodology. Beam forming is using a network of transducers that are used to sequentially scan the structure before and after the presence of damage by transmitting and receiving guided wave pulses. An image of the damage is reconstructed by analysing the cross correlation of the scatter signal with the excitation pulse and enables the detection and location of potential damage areas. The results of simulation and experimental studies show that the method enables the reliable detection of structural damages with locating inaccuracies in the order of a few millimeters within inspection areas of 300 x 300 mm2 using a transducer network of only four transducer elements.
Authors: Nurul Sabihah Zakaria, Rabizah Makhsin Siti, Azlan Abdul Aziz, Khairunisak Abdul Razak
Abstract: Colloidal gold or also known as gold nanoparticle (AuNP) is a suspension of sub-nanometer-sized particle of gold in a fluid usually water. The synthesized AuNP have particle sizes ranging from, e.g. 10 nm to 100 nm with color changing from an intense red color (for particle less than 100 nm) to a dirty yellowish color (for larger particle). The size of AuNP determines their unique optic, electronic and magnetic properties. AuNP nowadays has widely used in material science [ and biomedical [2,. For many of this application, the AuNP need to be monodispersed and have a specific size. Generally, colloidal AuNP can be synthesis as monodispersed nanoparticles with core sizes ranging from 1nm to 250nm. The synthesis of AuNP can be controlled in different size and shapes due to their ability to react and agglomerate with other nanoparticles in their ambient condition [. Furthermore, AuNP can also becomes more prone to flocculation and aggregation [. As the size of colloidal AuNP increase so do their sensitivity to salt and environment. AuNP have increasingly gain interest due to their unique properties ofcontrolable morphology [ and size dispersion [6,, less toxicity and ease in synthesis and detection.
Authors: Kyung Young Jhang, Jee Hong Jung, Hong Joon Kim, Min Kwan Hyeon
Authors: Maxim V. Trigub, Stanislav N. Torgaev, Gennadiy S. Evtushenko, Vitaliy V. Drobchik
Abstract: The imaging results of different processes blocked from the observation by the intense background light are presented in this paper. Active optical systems based on high-frequency brightness amplifier are used to decrease the negative factor of the glare. The experimental and modeling results on obtaining high pulse repetition frequencies (PRF) (more than 100 kHz) of copper bromide vapor brightness amplifiers operating in a low input energy mode are shown. The use of metal vapor brightness amplifiers for visual non-destructive testing of fast processes obscured by the glare is also discussed. It has been shown that the imaging method proposed in this paper proves to be the most reliable to obtain the information about objects or processes in a real time mode using high PRF CuBr active media.
Authors: Thomas Wroblewski, D. Breuer, H.A. Crostack, F. Fandrich, M. Gross, P. Klimanek
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