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1.
TD Blumenthal 《Canadian Metallurgical Quarterly》1994,31(2):201-203
In some laboratories, eyeblink electromyogram is rectified and smoothed before the analog signal is digitized. The relationship among the integrator time constant, the duration of the response, and the attenuation of the data was investigated by passing a number of signals at durations of 5, 10, 20, 50, and 100 ms into a contour-following integrator (Coulbourn model S76-01), which first rectifies and then smooths (integrates) the signal. Integrator time constants of 10, 42, 70, 144, and 300 ms were used. The output of the integrator was sampled (1,000 Hz) and stored on a Macintosh SE computer. The integrator attenuated the signal, and the amount of attenuation increased as the duration of the signal decreased and as the time constant of the integrator increased. For brief inputs, the integrator does not charge fully, so only the early portion of the charge limb is present, and this early portion is the steepest part of the charge limb. Therefore, the longer the time constant, the less likely that small or brief responses will be detected. 相似文献
2.
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
3.
Rectal and axillary temperatures were measured simultaneously in 83 children using three different thermometer devices providing 166 pairs of results. In the first series consisting of 22 febrile children (44 measurements) and 20 afebrile children (40 measurements), the rectal mercury measurement was compared to an axillary mercury and axillary Tempa-DOT thermometer. The axillary mercury had sensitivity of 14/22 (64%) and specificity of 20/20 (100%) while the Tempa-DOT had sensitivity of 15/22 (68%) and specificity of 19/20 (95%). In the second series comprising 21 febrile children (42 measurements) and 20 afebrile children (40 measurements) the axillary mercury had sensitivity of 11/21 (52%) and specificity of 20/20 (100%) while the electronic thermometer had sensitivity of 10/21 (48%) and specificity of 20/20 (100%). Regardless of the thermometer used, the axilla is a poor alternative to rectal measurements in the diagnosis of fever. CONCLUSION: Mercury-free thermometers, when used in the axilla are as poor alternatives to rectal measurements as mercury-in-glass thermometers. 相似文献
4.
BBN has an illustrious history of contributions to data networking, and has made repeated contributions in the development of networking protocols, network operations, router design, and wireless and satellite networks. Because so much of BBN's early Arpanet work has been documented elsewhere, this history focuses on post-Arpanet contributions that led to the Internet. Arpanet was a continuing source of inspiration, frustration, and innovation, both as a stand-alone network and then as the core of the Internet. 相似文献
5.
Membrane fusion mediated by interaction of the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein with the human CD4 molecule generally requires that the CD4 be expressed on a human cell. The failure of murine or simian cells expressing human CD4 to form syncytia upon mixing with cells expressing envelope glycoprotein could not be corrected by expression of both molecules at extremely high surface levels using vaccinia virus expression vectors. Video fluorescence microscopic analysis of fluorescent dye transfer between fusing cells indicated that the block occurred at the level of membrane fusion between individual pairs of cells. To gain insight into the basis for this fusion block, we tested the ability of fluorescent probe cells expressing envelope glycoprotein to fuse with transient animal x human hybrid giant cells expressing human CD4. The hybrid giant cells were generated either by low-pH-induced fusion of vaccinia-infected cells or by CD4/HIV-1 envelope glycoprotein-mediated cell fusion. We observed that envelope glycoprotein-expressing probe cells efficiently fused with CD4-expressing animal x human hybrid giant cells, independent of whether the CD4 was originally expressed on the animal or on the human cell. Fusion did not occur with CD4-expressing giant cells derived from animal cells alone. These results indicate that the fusion block is not due to dominant inhibitory components in the animal cell. Rather, they suggest that human cells contain an additional component(s) which, when transferred to the CD4-bearing animal cell, confers the ability to undergo membrane fusion mediated by the HIV-1 envelope glycoprotein. 相似文献
6.
Y. T Zhu S. T Taylor M. G Stout D. P Butt W. R Blumenthal T. C Lowe 《Journal of Materials Science》1998,33(6):1475-1480
Diameters vary significantly in a tow of commercial NicalonTM fibres, which is one of the most attractive ceramic reinforcements for structural composites. It was found that the strength distribution of Nicalon fibres could not be adequately characterized using either single- or bi-modal Weibull distribution. A recently proposed modified Weibull distribution can account for the effect of varying diameter in the characterization of fibre strength. To verify the validity of the modified Weibull distribution, comprehensive mechanical testing and fractographic studies have been conducted on Nicalon SiC fibres with diameters varying from 8 to 22 m. The experimental results have been reported in Part I. Part II of this paper further modifies the derivation of the modified Weibull distribution to yield a relationship which is similar in form, but soundly based on experimental findings. Factors considered in the modified Weibull distribution include the dependence of fracture toughness and flaw density on fibre diameter, both of which may vary with fibre diameter, as reported in Part I. Comparison with experimental data shows that the current modified Weibull distribution works very well, while both single-modal and bi-modal Weibull distributions are inadequate for describing Nicalon fibres with varying diameters. © 1998 Chapman & Hall 相似文献
7.
Liposome-cell interaction: transfer and intracellular release of a trapped fluorescent marker 总被引:4,自引:0,他引:4
JN Weinstein S Yoshikami P Henkart R Blumenthal WA Hagins 《Canadian Metallurgical Quarterly》1977,195(4277):489-492
When small, unilamellar lipid vesicles containing a high concentration of the fluorescent dye 6-carboxyfluorescein are incubated with either frog retinas or human lymphocytes, fluroescence distributes widely throughout each cell. Since "self-quenching" largely prevents the dye from fluorescing as long as it remains sequestered in vesicles, it is clear that a considerable amount of dye is released from the vesicles and diluted into the much larger volume of the cell. 相似文献
8.
M.N. Sysak J.W. Raring J.S. Barton M. Dummer D.J. Blumenthal L.A. Coldren 《Photonics Technology Letters, IEEE》2006,18(15):1630-1632
A monolithic integration platform is demonstrated for high functionality photonic circuits that include quantum-well electroabsorption modulators, semiconductor optical amplifiers, and widely tunable lasers. The platform is based on the selective removal of a set of active quantum wells located above an optical waveguide layer. The waveguide layer contains a second set of quantum wells to be used in modulator regions. Fabrication requires only a single blanket InP regrowth. 相似文献
9.
10.
Saul Blumenthal 《技术计量学》2013,55(2):205-218
In studying electron tube life, measuring the life of a tube in service in a system whose age is T amounts to lifelength proportional sampling. The problems of estimating mean life from such data are considered for finite T and for “equilibrium” (large T). Several variations on the straight-forward life-biased sampling plan which are avilable to the experimenter are mentioned and conditions are found under which these other sampling schemes would be better than the life-proportional scheme. Particular attention is paid to the gamma and Weibull families of distributions. Other applications of these results are discussed. 相似文献