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In this project, a design scheme that reinforcement welding machine is added within the steel framework is proposed according to the double-side welding technology for box-beam structure in marine engineering. Then the design and development of circuit and transmission mechanism for new welding equipment are completed as well with one sample machine being made. Moreover, the trial running is finished finally. Main technical parameters of the equipment are: the working stroke: ≥1500mm, the welding speed: 8∼15cm/min and the welding sheet thickness: ≥20mm.

application/pdf, Using a non-radioactive iodine-127 labeled cerebral perfusion agent (I-127 IMP), fluorescent X-ray computed tomography (FXCT) clearly revealed the cross-sectional distribution of I-127 IMP in normal mouse brain in-vivo. Cerebral perfusion of cortex and basal ganglion was depicted with 1 mm in-plane spatial resolution and 0.1 mm slice thickness. Degree of cerebral perfusion in basal ganglion was about 2-fold higher than that in cortical regions. This result suggests that in-vivo cerebral perfusion imaging is realized quantitatively by FXCT at high volumetric resolution.

application/pdf, Fluorescent X-ray CT (FXCT) to depict functional information and phase-contrast X-ray CT (PCCT) to demonstrate morphological information are being developed to analyze the disease model of small animal. To understand the detailed pathological state, integration of both functional and morphological image is very useful. The feasibility of image fusion between FXCT and PCCT were examined by using ex-vivo hearts injected fatty acid metabolic agent (127I-BMIPP) in normal and cardiomyopathic hamsters. Fusion images were reconstructed from each 3D image of FXCT and PCCT. 127I-BMIPP distribution within the heart was clearly demonstrated by FXCT with 0.25 mm spatial resolution. The detailed morphological image was obtained by PCCT at about 0.03 mm spatial resolution. Using image integration technique, metabolic abnormality of fatty acid in cardiomyopathic myocardium was easily recognized corresponding to anatomical structures. Our study suggests that image fusion provides important biomedical information even in FXCT and PCCT imaging.

application/pdf, Imaging of large objects at 17.7-keV low x-ray energy causes huge x-ray exposure to the objects even using interferometric phase-contrast x-ray CT (PCCT). Thus, we tried to obtain PCCT images at high x-ray energy of 35keV and examined the image quality using a formalin-fixed VX2 rabbit cancer specimen with 15-mm in diameter. The PCCT system consisted of an asymmetrically cut silicon (220) crystal, a monolithic x-ray interferometer, a phase-shifter, an object cell and an x-ray CCD camera. The PCCT at 35 keV clearly visualized various inner structures of VX2 rabbit cancer such as necrosis, cancer, the surrounding tumor vessels, and normal liver tissue. Besides, image-contrast was not degraded significantly. These results suggest that the PCCT at 35 KeV is sufficient to clearly depict the histopathological morphology of VX2 rabbit cancer specimen.

Phase‐contrast Computed Tomography (CT) delineates biological soft tissues, which cannot be clearly imaged using absorption‐contrast CT, at high contrast and high spatial resolution. Since the measurement system extracts phase‐shift information from interferograms acquired using an x‐ray interferometer, phase unwrapping is required to generate projections for CT reconstruction. In this research, we proposed a novel phase‐unwrap method based on 2‐dimensional auto regressive model (2‐D AR model). Then, we investigated the efficacy of the algorithm by simulation data generated from actual data acquired at KEK.

Self‐excited dust density waves (DDWs) are studied in a striped electrode device. In addition to the usual perpendicularly (with respect to the electrode) propagating DDWs, which have been frequently observed in dusty plasma experiments on the ground, a low‐frequency oblique mode is also observed. This low‐frequency oblique DDW has a frequency much lower than the dust plasma frequency and its spontaneous excitation is observed even with a very low dust density. It is found that the low‐frequency oblique mode can exist either separately or together with the usual perpendicular mode. In the latter case, a new mode arises as a result of the interactions between the perpendicular and the oblique modes. The experiments show that these three modes satisfy the wave coupling conditions in both the frequencies and the wave‐vectors.

A series of experiments were done to investigate the effect of laser parameters on laser propulsion. A high power high repetition rate TEA CO2 laser was employed in the experiments. The output energy of the laser is up to 15J and the repetition rate is up to 150 pps. The light craft models in the experiments were two parabolic aluminum shells with the exit diameter of 50 mm, the focus lengths were 5mm and 10mm respectively. The effect of the laser’s repetition rate on coupling coefficient was mainly investigated. The value of optimal repetition rate for laser propulsion of air‐breathing mode is discussed. On the basis of our investigation, a setup of laser propulsion demonstration experiment was designed. And laser‐powered free flight demonstration was realized. The 4.2g parabolic craft with 10mm focus length was boosted by the TEA CO2 laser to the altitude of more than 2.6m (limited by the ceiling of the laboratory) in a flight lasting 1.75s. The output pulse energy is 13J and the repetition rate is 50 pps.

The air‐breathing laser propulsion tests are conducted for parabolic models by using a high power TEA‐CO2 pulsed laser. It is found the momentum coupling coefficient Cm varies with the pulse repeatable frequency and reaches the maximum near 50Hz. With a multi‐use pendulum chamber, the change of Cm at different ambient pressure is measured. The experimental results show that the propulsion efficiency Cm does not decrease below the altitude of 10km, even increases a little bit. The calculated Cm fits the experimental result up to altitude 3km, then, they are separated. One possible reason is the temperature which is constant in the experiments.

An automotive underbody cross member was selected for one of the NUMISHEET’05 industrial benchmark to assess springback prediction capability of engineers around the world using various software. Binder and addendum were generated according to production intent process. Iterative design and draw simulation were performed on the part and addendum geometry to remove wrinkles and splits. Castings were poured and machined. Six different types of materials ranging from A15182‐O to DP965 were used in the production of the benchmark panels and three of these materials were included in the official benchmark data release. Draw panels were trimmed on a trimming fixture using laser and scanned with a whitelight optical device. Springback shapes at selected cross sections were recovered on the scanned data and original CAD data. In addition, major/minor and thickness strains were also measured at these sections.

Side‐wall‐curl is a springback phenomena in typical automotive structural components, such as channel like rails and cross members. Minimizing or eliminating the side‐wall‐curl is one of the major challenges in stamping production. This challenge is exasperated when the component is formed from advanced high strength steels (AHSS). In this study a standard three‐piece draw die is used, in a series of experimental tests, to form a stamping with a hat‐shaped section from dual phase 590 (DP590). During the forming stroke, the binder force is varied to evaluate its influence on side‐wall‐curl. FEA springback simulations for two types of experiments with varied binder forces are also performed. The binder force profiles for several sheet materials are discussed and the correlation between the simulation results and the actual part measurements are illustrated.

To more accurately suppress the phase fluctuation of the interference beams of a large‐area phase‐contrast X‐ray imaging system using a two‐crystal X‐ray interferometer, a new feedback positioning system (FPS) has been developed and applied. The motion of interference patterns replaces the intensity of the interference beam in a small region as the feedback signal used in controlling the rotation of crystal blocks relative to each other. This FPS kept the phase fluctuation of the interference beams within π/15 over more than six hours. Examples of high‐quality two and three‐dimensional images of biological samples obtained by the imaging system with the new FPS are given.