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961.
J. A. Xia H. T. Ren P. R. Munroe Y. Zhao H. K. Liu C. Andrikidis S. X. Dou 《Journal of Superconductivity and Novel Magnetism》1994,7(6):947-950
Silver has been previously added to the melt-textured YBa2Cu3O7?x in order to increase the critical current density (J c ) of these materials. However, the effect of this addition on theJ c is presently unclear. The purpose of this study is to investigate the effect of silver on both critical current density and the microstructure of the melt-textured YBa2Cu3O7?x superconductors by means of X-ray diffraction, optical polarized microscopy, and transmission electron microscopy (TEM). TheJ c of the MTG YBCO/Ag samples is more than 104A/cm2 under the 5 kOe magnetic field. It has been shown that as the concentration of silver increases, the fraction of the 211 phase dispersed within the 123 matrix decreases. Therefore, theJ c slightly decreases. These results, together with the effect of the 211 phase, dislocations, and other structure defects on flux pinning, are described in this paper. 相似文献
962.
The numerical optimisation of existing low voltage BiCMOS buffer designs allows a valid comparison of performance. A new bootstrap BiCMOS buffer design, which combines temporary saturation and a bootstrap capacitor, is shown to be the fastest under all conditions. The new design operates down to a supply voltage of 1.1 V 相似文献
963.
964.
For viruses made of nucleic acid and protein, the structure of the protein outer shell has, in the past, been found to be uniquely determined by the viral genome. However, here, non-denaturing agarose gel electrophoresis of bacteriophage T7 reveals two states of the mature T7 capsid; the conditions of growth are found to alter the population by T7 of these two electrophoretically defined states. Both states have been previously observed for a genetically altered T7 and they are observed here for wild-type T7. The average electrical surface charge density of a bacteriophage particle (delta) determines its state; the delta of particles in both states is negative. For a given condition of growth, the population of these two states is influenced by the extent to which the major T7 outer shell protein, p10A, is accompanied by its minor readthrough variant, p10B. Comparison of the two electrophoretic states reveals the following. (1) No difference in radius is present in the outer shell (+/-2%). (2) As the pH of electrophoresis is either increased or decreased from neutrality, the state becomes more highly populated for which delta is greater in magnitude (state 1). By changing the pH, some T7 particles are made to change state. (3) Particles in state 1 adsorb less quickly to host cells than do the particles in the alternative state (state 2). This latter observation suggests the hypothesis that state 1 evolved to reduce the probability of re-initiating an infection when conditions are not favorable for growth. This hypothesis is supported by the observation that, as conditions of growth become apparently more unfavorable, progeny increasingly populate state 1. 相似文献
965.
Wireless ATM networks require efficient mobility management to cope with frequent mobile handoff and rerouting of connections. Although much attention has been given in the literature to network architecture design to support wide-area mobility in public ATM networks, little has been done to the important issue of user mobility estimation and prediction to improve the connection reliability and bandwidth efficiency of the underlying system architecture. This paper treats the problem by developing a hierarchical user mobility model that closely represents the movement behavior of a mobile user, and that, when used with appropriate pattern matching and Kalman filtering techniques, yields an accurate location prediction algorithm, HLP, or hierarchical location prediction, which provides necessary information for advance resource reservation and advance optimal route establishment in wireless ATM networks 相似文献
966.
This work demonstrates that for constant oxide reliability stresses in the Fowler-Nordheim regime a low initial rate of charge trapping/detrapping results in long times to breakdown. It was found for MOS gate oxides that when the initial trapping has been completed at low fields times to breakdown enhance. Depending on the stress sequence measurement results can vary significantly which is of great relevance for correct oxide lifetime predictions. 相似文献
967.
Ohne Zusammenfassung 相似文献
968.
V. P. Evtikhiev I. V. Kudryashov E. Yu. Kotel’nikov V. E. Tokranov A. N. Titkov I. S. Tarasov Zh. I. Alferov 《Semiconductors》1998,32(12):1323-1327
The electroluminescence and stimulated emission of lasers with one layer of InAs quantum dots (QD’s) grown in a single molecular-beam
epitaxial process on vicinal GaAs(001) surfaces misoriented in the direction [010] by 2, 4 and 6° are investigated. It is
discovered that an increase in the misorientation angle leads to a blue shift and a decrease in the full width at half maximum
(FWHM) of the electroluminescence spectrum. This effect is attributed to a decrease in the size of the quantum dots and improvement
in their size uniformity. A strong dependence of the threshold current density on the width of the spontaneous luminescence
spectrum is discovered. The room-temperature threshold current density of the lasers with one layer of quantum dots and the
spontaneous luminescence spectrum having the smallest FWHM (54 meV) equals 210 A/cm2.
Fiz. Tekh. Poluprovodn. 32, 1482–1486 (December 1998) 相似文献
969.
970.