A 3 times 3 MIMO baseband and MAC processor in 0.18 mum 6M CMOS occupies 62.1 mm 2 and dissipates (Tx/Rx) 1379/1200mW at 1.8V including ADCs, DACs, and PCI/PCIe PHY. The integrated BB and MAC ...delivers up to 300Mb/s in 40MHz bandwidth, greater than 150Mb/s TCP throughput best case and a maximum range of 700ft range.
How black holes accrete surrounding matter is a fundamental, yet unsolved question in astrophysics. It is generally believed that matter is absorbed into black holes via accretion disks, the state of ...which depends primarily on the mass-accretion rate. When this rate approaches the critical rate (the Eddington limit), thermal instability is supposed to occur in the inner disc, causing repetitive patterns of large-amplitude X-ray variability (oscillations) on timescales of minutes to hours. In fact, such oscillations have been observed only in sources with a high mass accretion rate, such as GRS 1915+105. These large-amplitude, relatively slow timescale, phenomena are thought to have physical origins distinct from X-ray or optical variations with small amplitudes and fast (\(\lesssim\)10 sec) timescales often observed in other black hole binaries (e.g., XTE J1118+480 and GX 339-4). Here we report an extensive multi-colour optical photometric data set of V404 Cygni, an X-ray transient source containing a black hole of nine solar masses (and a conpanion star) at a distance of 2.4 kiloparsecs. Our data show that optical oscillations on timescales of 100 seconds to 2.5 hours can occur at mass-accretion rates more than ten times lower than previously thought. This suggests that the accretion rate is not the critical parameter for inducing inner-disc instabilities. Instead, we propose that a long orbital period is a key condition for these large-amplitude oscillations, because the outer part of the large disc in binaries with long orbital periods will have surface densities too low to maintain sustained mass accretion to the inner part of the disc. The lack of sustained accretion -- not the actual rate -- would then be the critical factor causing large-amplitude oscillations in long-period systems.
Extracting rebar's reflection from measured GPR data Jing Li; Huichun Xing; Xuemin Chen ...
Proceedings of the Tenth International Conference on Grounds Penetrating Radar, 2004. GPR 2004,
2004, Letnik:
1
Conference Proceeding
Compare to the core sampling method for obtaining pavement layer parameters, which is time consuming, labor intensive, and provides limited coverage, GPR method is far more economical, faster, and ...easier to use. However, one defect of the GPR method is that the measurement tolerance is, so far, lower than the core sampling method. To improve the measuring accuracy of GPR method is a very important task to the GPR developers. For the rebar-free pavement, many algorithms have been proposed to accurately determine the layer parameters from GPR data. For the rebar-reinforced concrete pavement, the rebar's effect is an important factor that influences the determination of pavement thickness from GPR data. Though some features of rebar's reflection have been studied, like the data collected along traverses showing rebar as individual scattering hyperbola, or rebar responding strongly to the incident GPR waves only when the rebar is located parallel to the polarization of GPR antennas, how to extract rebar's scattering fields from the measured GPR data and cancel rebar's influence in pavement thickness estimation have not been reported. In this paper, a new algorithm for extracting rebar's reflection fields from measured GPR data is proposed. This algorithm uses two-dimensional GPR data to establish a set of functional, the variables of which include rebar depths, rebar spacing, pavement thickness, pavement electrical parameters, GPR transmitted waveform and rebar's reflection fields. By minimizing the established functional, the above variables can be determined. The proposed algorithm not only extracts the rebar's reflection fields, but also solves the other pavement parameters. With the implementation of the proposed algorithm, the measured results on highways show that the measurement tolerance is less than 5%.
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