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  • 1
    Electronic Resource
    Electronic Resource
    High-resolution transmission electron microscopy of cubic Si3N4 (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 88 (2000), S. 3070-3072 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A cubic Si3N4 phase/nanostructure has been characterized by means of high-resolution analytical electron microscopy. The specimen prepared from β-Si3N4 powders at a high pressure and temperature by shock wave compression contained nanometer-sized Si3N4 crystallites. The results of nano-beam electron diffraction analysis and high-resolution lattice images as well as computer simulations revealed that the Si3N4 crystallites had a cubic symmetry with spinel structure. The electron energy loss spectrum suggested that the chemical compositions of these nanostructures were close to Si3N4. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1287765
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  • 2
    Electronic Resource
    Electronic Resource
    Simple and inexpensive interferometry of shock wave developments from pulsed high-current discharge (2000)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 71 (2000), S. 1548-1551 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Interferometer measurements are extremely informative in shock wave studies allowing direct evaluations of the gas density. The primary goal of the work presented is to build a laser interferometer that meets the requirements of the highest possible simplicity, economy, convenience, and ease of construction. In our experiments, we used a low average power (10 mW) He–Ne laser without complication, expense, and environmental section. The He–Ne laser interferometer with the Michelson arrangement was used to measure the line-averaged gas densities of shock waves. Temporal and spatial measurements of the density were performed for shock wave developments from high-current pulse discharges. The shock wave propagates in the radial direction of the discharge channel with supersonic speed. The shock velocity, however, decreased from 2–0.5 km/s with the distance of the shock propagation. The width of the high density region, that is in the vicinity of the shock front was compressed from 3.5 to 1.8 mm according to the time variation of the discharge current. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1150492
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  • 3
    Electronic Resource
    Electronic Resource
    Mössbauer study on intergranular phases in the bcc-Fe/NdFeB nanocomposite alloys (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 87 (2000), S. 6579-6581 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Magnetic properties of the intergranular phase in the bcc-Fe/NdFeB nanocomposite alloys containing Nb and Co were investigated with Mössbauer spectroscopy. The alloys were prepared with melt-spinning and post-annealing method. It is revealed that the intergranular phase is not amorphous as considered so far and consists of several thin layers outside the nanoscale grains of bcc-Fe and Nd2Fe14B. The hyperfine field in the layer on the surface of the grain is rather strong and the structure of this layer is similar to the grain. The field in the outer layers is reduced because the structure becomes indistinct gradually as the layer is apart from the grain. The high remanence and coercive field of the nanocomposite alloys may originate from the magnetic coupling between grains via the intergranular ferromagnetic phase. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.372776
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  • 4
    Electronic Resource
    Electronic Resource
    Shock-induced transformation of β-Si3N4 to a high-pressure cubic-spinel phase (2000)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 76 (2000), S. 3706-3708 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: β-Si3N4 powders were shock compressed and quenched from 12 to 115 GPa. β-Si3N4 transforms to the spinel-type Si3N4 (c-Si3N4) by a fast reconstructive process at pressures above about 20 GPa. The yield of c-Si3N4 recovered from 50 GPa and about 2400 K reaches about 80% and the grain sizes are about 10–50 nm. It is proposed that the fast transformation to c-Si3N4 occurs by rearrangement of nitrogen stacking layers, which initiates partial breakup of the SiN4 tetrahedra and formation of SiN6 octahedra at high density. Because of the advantages of massive production and the nanometer characteristics of shock-synthesized c-Si3N4, it is possible to investigate the mechanical properties experimentally and to develop new industrial applications. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.126756
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  • 5
    Electronic Resource
    Electronic Resource
    Angiotropic lymphoma: proliferation of B cells in the capillaries of cutaneous angiomas (2000)
    Oxford, UK : Blackwell Science Ltd
    British journal of dermatology 143 (2000), S. 0 
    Details
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: We report a 52-year-old patient with cutaneous angiomas on the trunk in association with angiotropic lymphoma involving the nervous system. The lesional skin showed proliferation of atypical B cells in the capillaries. The diagnosis of angiotropic lymphoma with neurological deficits is often difficult before death. Thus, skin biopsy in this case proved to be diagnostic of the central nervous system disease without the risk of brain biopsy. The diagnosis of angiotropic lymphoma in the future may be achievable by biopsy of coincidental angiomas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2133.2000.03608.x
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  • 6
    Electronic Resource
    Electronic Resource
    Stent Implantation for Native Coarctation of the Aorta: Lessons Learned from a Case Involving a 17-Year-Old Patient (2000)
    Springer
    Pediatric cardiology 21 (2000), S. 483-486 
    Details
    ISSN: 1432-1971
    Keywords: Key words: Stent — Coarctation of the arota — Complication
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Recent studies have shown that stenting for coarctation of the aorta (CoA) may be an effective treatment modality for this disease. We report a case of stent repair of CoA in a 17-year-old patient. An incompletely expanded stent caused by a balloon rupture had been implanted in the femoral artery. Subsequent implantation for CoA was successfully achieved using a high-profile balloon catheter. Stent implantation may be an effective modality for CoA repair and may prove useful as an initial procedure for adolescents and adults with CoA. However, one must consider that incomplete expansion of a stent associated with dilatation balloon rupture can cause serious complications. The current case raises important issues that require further discussion to improve the results of this procedure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00246010117
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  • 7
    Electronic Resource
    Electronic Resource
    Single-frame (two-field image) 3-D PTV for high speed flows (2000)
    Springer
    Experiments in fluids 29 (2000), S. S085 
    Details
    ISSN: 1432-1114
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A single-frame 3-D PTV algorithm was constructed to measure 3-D high-speed flows with NTSC cameras. The measurement system consists of three NTSC cameras, an optical instrument called AOM, a digital image grabber and a hosting computer. The tracking algorithm of particles' pair is based on a concept of a spatial match probability. The measurement system is used to probe the turbulent properties of the backward-facing step flow. A preliminary test of the measurement system is also made on the measurement of 3-D vectors of 36 targets on a rotating table to verify its validity. The measurement uncertainty of the system is systematically evaluated through the preliminary test. A set of virtual images is constructed by using the vectors selected randomly from the grid vectors that had been obtained by the experiment on the backward-facing step flow with the system. A performance test is made on the vector recovery using the virtual images and it is validated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003480070011
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  • 8
    Electronic Resource
    Electronic Resource
    Particle image velocimetry and planar laser-induced fluorescence measurements on lobed jet mixing flows (2000)
    Springer
    Experiments in fluids 29 (2000), S. S141 
    Details
    ISSN: 1432-1114
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract  An experimental investigation of the vortical and turbulent structures in lobed jet mixing flows was conducted. The techniques of planar laser-induced fluorescence (PLIF) and particle image velocimetry (PIV) were used to accomplish flow visualisation and velocity filed measurements of the lobed jet mixing flows. Compared with a conventional circular jet flow, the lobed jet mixing flows were found to have a shorter laminar region, a smaller scale of spanwise Kelvin–Helmholtz vortices, quicker transition to turbulence and earlier appearance of small-scale vortical and turbulent structures. The intensive mixing of the core jet flow with ambient flow was found to concentrate within the first two nozzle diameters in the lobed jet mixing flow. More rapid growth of the shear layer at the near field and quicker decay of the central line velocity were also found in the lobed jet mixing flow. All these indicated a better mixing enhancement performance of the lobed nozzle compared with the conventional circular nozzle in the near-field region. Based on the PLIF and PIV results, two aspects of the mechanism of mixing enhancement in a lobed jet mixing flow were suggested. One is that a lobed nozzle can cause big azimuthal perturbations in the jet flow due to its special geometry, and the streamwise vortices produced by the lobed nozzle can enhanced the azimuthal perturbations. The “cut and connect” process of the large-scale spanwise Kelvin–Helmholtz vortex rings was accelerated. This is responsible for the avalanche of three-dimensional and smaller-scale motions and the generation of high turbulence. Another is that the “stretch effect” of streamwise vortices generated by the lobed nozzle on the spanwise Kelvin–Helmholtz vortical rings reduced the scale of the spanwise Kelvin–Helmholtz vortices, which also results in the creation of much small-scale intense turbulence and enhances the mixing of the core jet flow with the ambient flow.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003480070016
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  • 9
    Electronic Resource
    Electronic Resource
    Intrahepatic biliary calculi: correlation of unusual MR findings with pathologic findings (2000)
    Springer
    Abdominal imaging 25 (2000), S. 266-268 
    Details
    ISSN: 1432-0509
    Keywords: Key words: Liver—Biliary—Calculi—Magnetic resonance imaging.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We report a case of intrahepatic biliary calculi. A localized dilated intrahepatic duct of the left lateral segment of the liver was filled with material that showed marked hyperintensity on T1- and T2-weighted magnetic resonance (MR) images. These MR findings are unusual for intrahepatic stones. Pathologically, the stones were muddy bilirubin calculi, the chemical and physical characteristics of which are surmised to have been the cause of the unusual MR findings.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002610000030
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  • 10
    Electronic Resource
    Electronic Resource
    Tunable visible and near-infrared pulse generator in a 5 fs regime (2000)
    Springer
    Applied physics 70 (2000), S. S239 
    Details
    ISSN: 1432-0649
    Keywords: PACS: 42.65.Re; 42.65.Yj; 42.62.Fi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. Transform-limited (TL) visible pulses with as short a duration as 4.7 fs with a 5 μJ pulse energy have been generated for the first time from a novel noncollinear optical parametric amplifier (NOPA). Both signal–idler group-velocity matching and pulse-front matching are essential to generate coherent down-converted pulses compressible to the TL pulse with more than a 150-THz bandwidth. Tunable operation with bandwidth-limited sub-10-fs pulses in the visible (550–700 nm) and near-infrared (900–1300 nm) ranges, achieved by increasing the seed chirp, is also a remarkable property. The NOPA is believed to be on useful light source for ultrafast spectroscopy on an extremely short time-scale.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003400000325
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