Papers by Keyword: Imaging

Abstract: The combustion engines are widely used in the daily life of people, in cars, we find them with greater emphasis, and currently hybrid engines and electric motors are being used. In this analysis, one of the important factors for the failure of combustion engines is the temperature, for which cars have cooling systems, through the use of radiators and coolant-based systems. In this work we present a methodology for the analysis of the state of the components of the combustion engine system in cars, through the use and analysis of thermal images, for which it is necessary to identify the zones or control points depending on the model and type of engine and car, The analysis procedure requires a thermal camera, the results presented are related to the comparison of an optical and thermal image, in order to locate the control point, the method can be applied by mechanics, maintenance personnel and car drivers themselves, to analyze the condition of their car.

Abstract: A synergic combination of neutron techniques was applied to characterize non-invasively the laminated structure of a set of ancient katana, part of the East Asian Collection of the Museum of Applied Arts and Sciences (MAAS) in Sydney. Neutron tomography, diffraction, residual stress and Bragg-edge transmission analyses were undertaken on samples of well-known origin, time period and authorship to create a reference database on the main manufacturing methods developed by Japanese swordsmiths. In the attempt to attribute mumei (no-signature) blades basing on a scientific analytical method rather than a stylistic analysis, data from the reference samples were benchmarked against the results obtained from the unknown blade to identify differences and commonalities in the production process.

Abstract: Electrical testing with regard to bipolar degradation of high voltage SiC devices cannot be done on wafer level, but only expensively after module assembly. We show that 4H-SiC material can be optically stressed by applying high UV laser intensities, i.e. bipolar degradation as in electrical stress tests can be provoked on wafer level. Therefore, optical stressing can be used for control measurements and reliability testing. Different injection (=stress) levels have been used similar to the typical doping level of the base material and similar to the established electrical stress test. The analysis of degradation is done by photoluminescence imaging which is a well-established technique for revealing structural defects such as Basal Plane Dislocations (BPDs) and stacking faults (SFs) in 4H-SiC epiwafers and partially processed devices.

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.

Abstract: This paper investigates the effect of 1 wt% TiO₂ on the formation of primary and interfacial Cu₆Sn₅ in Sn-0.7wt%Cu and Sn-0.7wt%Cu-0.05wt%Ni solder pastes soldered on a Cu substrate using a real-time synchrotron imaging technique. It was found that TiO₂ had altered the nucleation time of the primary Cu₆Sn₅ intermetallics and increased the number of particles observed. In addition, a more planar Cu₆Sn₅ interfacial layer had formed in joints made with TiO₂ reinforced solders. This indicated that TiO₂ promotes nucleation of primary Cu₆Sn₅ intermetallics in the early stages of soldering while being a barrier for further growth of interfacial Cu₆Sn₅ intermetallics. The synchrotron imaging technique provides direct evidence of the sequence of events in the soldering reaction and how these are influenced by TiO₂ reinforcement.

Abstract: This paper describes 3D imaging of extended defects in 4H-SiC using optical second-harmonic generation (SHG) and two-photon-exited photoluminescence (2PPL). SHG selectively yields the 3D images of 3C-inclusions in a 4H-SiC epilayer, while 2PPL provides 3D images of 3C-inclusions, 8H stacking faults and single Shockley stacking faults. 2PPL band-edge emission visualizes dislocation lines of threading screw dislocations and threading edge dislocations, the tilt angles of which are evaluated.

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.

Abstract: This article presents a human head phantom characterization based on the study of its electrical properties across 1 to 6 GHz. The study focuses on the grey matter, white matter, cerebral spinal fluid (CSF), blood and skin of human head. Through the investigation and study of the human head characteristics, its phantom can be modeled using simple and common materials, which are gelatin, water and sugar. The electrical properties of the chosen mixtures of materials mimicking the electrical properties of human head are measured using special dielectric probe connected to a vector network analyser (VNA). This human head phantom later can be applied in the microwave imaging system for a further study on the health monitoring of human body.

Abstract: This paper demonstrates the development of an experimental technique of in-situ observation for soldering of Sn-0.7wt%Cu lead-free solder on a Cu substrate which was achieved for the first time by synchrotron X-ray imaging. Reactions between liquid solder and Cu substrate during a soldering process were able to be recorded in real-time. Individual stages of the soldering process consisted of flux activation in removal of Cu oxide, solder melting and contact with the Cu substrate (wetting) and intermetallic compound (IMC) and void formation between the solder and Cu substrate. The technique development which includes experimental setup with calculated optimum beam energy in the range of 20 – 30 keV appears to result in a clear observation of real-time X-ray imaging of the soldering process. This technique provides a key method to understand the mechanism of formation of micro-electronic inter-connects for future electronic packaging applications.

Abstract: In this paper,it is established the geometric and radar echo model of the rotating target with the Forward-looking synthetic aperture radar firstly,then the Doppler frequency History Formula is Deduced and Pointed out that the Formula has a sinusoidal characteristics. It is simulated the imaging of the stationary target and the rotating target with different rotation speed, the imaging result can be expressed as the forms of curve and the curve circle nomadic type, when these features appear in the imaging results, it can initially determine that the rotating target is presence.