785 research outputs found
Observations of solar energetic particles at a synchronous orbit
The Space Environment Monitors (SEM) on board the Japanese geostationary meteorological satellites (GMS-1 and GMS-2) observed energetic protons, alpha particles and electrons continuously for February 1978 to September 1984. The satellites were at 6.6 Earth radii above 140 deg E equator
Possibility of Macroscopic resonant Tunneling near the Superconductor- Insulator Transition in YBaCuO Thin Films
Experimental results of I-V characteristics near the superconductor-insulator
transition observed for disorder-tuned YBaCuO thinfilms are presented. The I-V
characteristics exibit new quasiperiodic structures as a function of the
current. The current interval, the number of the dI/dV peaks, and the magnetic
field dependence of the peaks are consistent with the theoretical predictions
of the resonant tunneling of a phase particle ina tilted-cosine potential for
asingle Josephson junction with small capacitance.Comment: 7 pages, 4 figures, in press (Europhys. Lett.
Color Changes in Electronic Endoscopic Images Caused by Image Compression
In recent years, recording of color still images into magneto–optical video disks has been
increasingly used as a method for recording electronic endoscopic images. In this case,
image compression is often used to reduce the volume and cost of recording media and
also to minimize the time required for image recording and playback. With this in mind,
we recorded 8 images into a magneto-optical video disk in 4 image compression modes
(no compression, weak compression, moderate compression, and strong compression)
using the Joint Photographic Image Coding Experts Group (JPEG) system, which is a
widely used and representative method for compressing color still images, in order to
determine the relationship between the degree of image compression and the color
information in electronic endoscopic images. The acquired images were transferred to an
image processor using an offline system. A total of 10 regions of interest (ROls) were
selected, and red (R), green (G), and blue (B) images were obtained using different
compression modes. From histograms generated for these images, mean densities of R,
G, and B in each ROI were measured and analyzed. The results revealed that color
changes were greater for B, which had the lowest density, than for R or G as the degree
of compression was increased
SHG microscopic observations of polar state in Li-doped KTaO3 under electric field
Incipient ferroelectric KTaO3 with off-center Li impurity of the critical
concentration of 2.8 mol% was investigated in order to clarify the dipole glass
state under electric field. Using optical second-harmonic generation (SHG)
microscope, we observed a marked history dependence of SHG intensity through
zero-field cooling (ZFC), zero-field heating (ZFH), field heating after ZFC
(FH/ZFC) and FH after field cooling (FH/FC). These show different paths with
respect to temperature: In the ZFC/ZFH process, weak SHG was observed at low
temperature, while in the FH/ZFC process, relatively high SHG appears in a
limited temperature range below TF depending on the field strength, and in the
FC and FH/FC processes, the SHG exhibits ferroelectric-like temperature
dependence: it appears at the freezing temperature of 50K, increases with
decreasing temperature and has a tendency of saturation. These experimental
results strongly suggest that dipole glass state or polar nano-clusters which
gradually freezes with decreasing temperature is transformed into
semi-macroscopic polar state under the electric field. However at sufficiently
low temperature, the freezing is so strong that the electric field cannot
enlarge the polar clusters. These experimental results show that the polar
nano-cluster model similar to relaxors would be more relevant in KTaO3 doped
with the critical concentration of Li. Further experiments on the anisotropy of
SHG determine that the average symmetry of the field-induced polar phase is
tetragonal 4mm or 4, which is also confirmed by the X-ray diffraction
measurement.Comment: 26 pages, 8 figures, 1 tabl
Magnified Examination of Small Colorectal Polyps Using a Prototype Electronic Endoscope
Magnifying electronic endoscopes are frequently used to evaluate the pit patterns of the
colorectal mucosa, but such endoscopes suffer from a number of problems. For example, they
tend to have long, hard tips and heavy controller sections. In addition, the magnified
endoscopic images obtained are often quite coarse due to the small number of pixels in the
charge-coupled device (CCD). As a result, at higher magnification ratios, the orientation of
the field of view is easily lost. A newly developed prototype colorectal electronic endoscope
(Toshiba Corporation, Tokyo) overcomes these problems. The length of the hard tip of the
scope and the weight of the controller section are comparable to those of the TCE-3680MH
(Toshiba Corporation). High-resolution magnified images can be obtained, because a
410,000-pixel CCD is employed. Two magnification methods are available, optical
magnification and electronic zooming, permitting images to be magnified by a factor of up
to 90–120 without losing the orientation of the field of view. This newly developed magnifying
electronic endoscope was found to be very useful, allowing us to observe the pit patterns of the
colorectal mucosa in 82 small colorectal polyps measuring 7 mm or less in diameter
A Woods-Saxon Optical-Model Description of 14N Elastic and Inelastic Scattering from 27Al and 28Si
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Analysis of Buoyancy-Driven Ventilation of Hydrogen from Buildings: Preprint
When hydrogen gas is used or stored within a building, as with a hydrogen-powered vehicle parked in a residential garage, any leakage of unignited H2 will mix with indoor air and may form a flammable mixture. One approach to safety engineering relies on buoyancy-driven, passive ventilation of H2 from the building through vents to the outside
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Analysis of Buoyancy-Driven Ventilation of Hydrogen from Buildings
The scope of work for this project includes safe building design, vehicle leak in residential garage, continual slow leak, passive, buoyancy-driven ventilation (versus mechanical), and steady-state concentration of hydrogen versus vent size
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