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991.
G. P. Ledneva 《Journal of Engineering Physics and Thermophysics》1994,67(3-4):960-964
Heating of spherical alumina particles by high-intensity laser radiation under vacuum conditions to the melting temperature is investigated with account for the nonuniform distribution of energy sources with respect to the particle volume.B. I. Stepanov Institute of Physics, Academy of Sciences of Belarus, Minsk. Translated fron Inzhenerno-Fizicheskii Zhurnal, Vol. 67, Nos. 3–4, pp. 307–312, September–October, 1994. 相似文献
992.
V. V. Bobrovskii V. R. Shevchenko 《Journal of Engineering Physics and Thermophysics》1994,66(1):26-29
The reaction between chlorine and an alkaline solution of hydrogen peroxide is suggested for the investigation of chemothermocapillary convection [1].Vitebsk Branch of the Institute of Solid State and Semiconductors Physics, Academy of Sciences of Belarus, Vitebsk, Belarus. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 66, No. 1, pp. 30–33, January, 1994. 相似文献
993.
V Raptopoulos 《Canadian Metallurgical Quarterly》1994,32(5):969-987
CT scans have been the champion in the diagnosis and management of abdominal injuries, and their use has decreased the number of negative exploratory laparotomies. Traditional areas for the use of CT scans include the assessment of injuries to the spleen and the liver and to signs of organ rupture into the peritoneal cavity. New technologic advances and increased experience have expanded the value of this modality to less than hemodynamically stable patients as well as to less common and more difficult to diagnose injuries of the pancreas, bowel, and the mesentery. 相似文献
994.
R Gouider E LeGuern J Emile S Tardieu F Cabon M Samid J Weissenbach Y Agid P Bouche A Brice 《Canadian Metallurgical Quarterly》1994,44(12):2250-2252
Fistulas secondary to Crohn's disease occur in about 33% of patients. A colobronchial fistula complicating Crohn's disease is very rare, having been reported only twice previously. We present an unusual fistula secondary to Crohn's colitis that originated from the splenic flexure and crossed the diaphragm to involve the bronchial tree. 相似文献
995.
Investigates adaptive digital notch filters for the elimination of powerline noise from biomedical signals. Since the distribution of the frequency variation of the powerline noise may or may not be centered at 60 Hz. Three different adaptive digital notch filters are considered. For the first case, an adaptive FIR second-order digital notch filter is designed to track the center frequency variation. For the second case, the zeroes of an adaptive IIR second-order digital notch filter are fixed on the unit circle and the poles are adapted to find an optimum bandwidth to eliminate the noise to a pre-defined attenuation level. In the third case, both the poles and zeroes of the adaptive IIR second-order filter are adapted to track the center frequency variation within an optimum bandwidth. The adaptive process is considerably simplified by designing the notch filters by pole-zero placement on the unit circle using some suggested rules. A constrained least mean-squared algorithm is used for the adaptive process. To evaluate their performance, the three adaptive notch filters are applied to a powerline noise sample and to a noisy EEG as an illustration of a biomedical signal 相似文献
996.
The authors describe a scalable neural system, HyperNet, based on a probabilistic RAM-based architecture and using a custom VLSI IC. A system using five HyperNet VLSI ICs and capable of realising up to 10240 neurons has been designed, manufactured and demonstrated to have the potential to learn more than three orders of magnitude faster than simulations on current workstations 相似文献
997.
Blumenthal D.J. Prucnal P.R. Sauer J.R. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1994,82(11):1650-1667
Photonic packet switches offer high speed, data rate and format transparency, and flexibility required by future computer communications and cell-based telecommunications networks. In this paper, we review experimental progress in state-of-the-art photonic packet switches with an emphasis on all-optical guided-wave systems. The term all-optical implies that the data portion of a packet remains in optical format from the source to the destination. While the data remain all-optical, both optical and optoelectronic techniques have been used to process packet routing functions based on extremely simple routing protocols. An overview of the design issues for all-optical photonic packet switching is given and contrasted with electronic packet switch implementations. Low-level functions that have been experimentally implemented include routing, contention resolution, synchronization, and header regeneration. System level demonstrations, including centralized photonic switching and distributed all-optical multihop networks, will be reviewed 相似文献
998.
A computer method for the calculation of the phase shift due to optically injected carriers in an InP avalanche transit time diode has been suggested using the numerically simulated negative resistance profiles in the depletion layer of the diode. The results show that the phase shift due to hole injection is larger than that due to electron injection which explains the pronounced effect of photogenerated hole leakage current in modulating the microwave properties of InP diodes 相似文献
999.
Characterization of a diffusion-bonded Al-Mg alloy/SiC interface by high resolution and analytical electron microscopy 总被引:6,自引:0,他引:6
The interfacial structure of a diffusion-bonded Al-4.55 at. pct Mg/SiC interface was examined by conventional and high-resolution
transmission electron microscopy. Formation of Mg2Si, MgO, and Al2MgO4 was observed. The monoclinic Mg2Si phase formed at the Al/SiC interface, while the oxides MgO and Al2MgO4 formed at the monoclinic Mg2Si/Al interface. It is shown that the formation of these phases can be predicted using simple thermodynamic criteria such
as the relative bond strengths between Al, Si, C, O, and Mg. In addition, precipitation of some equilibrium Al8Mg5 precipitate was also observed at the interface. The interfacial structure observed in the Al-Mg/SiC system is contrasted
with that observed in the pure Al/SiC system. 相似文献
1000.
V. V. Veremey A. A. Kostenko I. K. Kuz'michev A. E. Poyedinchuk G. I. Khlopov 《Journal of Infrared, Millimeter and Terahertz Waves》1994,15(7):1283-1295
Reported here are the results on level and structure of the radiated field of an open resonator at and off resonance. On the basis of the modelling problem rigorous solution and the measurements at 4-millimeter wavelength we find there are no ways to compensate the radiated field from an open electromagnetic structure at resonance. Analysis of open resonator excitation efficiency shows that the mismatch loss of a slot-fed open resonator runs to 34% while at the aperture-feed excitation this is not more than 6% for the same-geometry resonator. 相似文献