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Santella, Giovanni The Korean Institute of Communications and Informa 1999 Journal of communications and networks Vol.1 No.3
The object of this paper is to investigate the influence of antenna pattern on indoor radio channel characteristics. Different from previous works where this analysis was carried out at a fixed frequency using different antennas, in the present paper (where measurements were taken in a wide frequency range) the variation of the radiation pattern was caused by two factors: the change of the radiation pattern when the same antenna was used at different frequenicies and the use of different type of antennas. To carry out this analysis, frequency domain measurements of the indoor radio channel at 1 GHz, 5.5 GHz, 10 GHz and 18 GHz were collected. Measurements were taken using a network analyzer. Serveral re-alizations of the channel transfer function were obtained varying, for each measurement, the positon of the transmitter and keep-ing the receiver fixed. Estimate of the channel impulse response was obtained from the Inverse Fourier Transform (IFT) of the fre-quency response. The measurements were performed in an office enviroment with mostly metallic walls and inner separations. The obtained data were elaborated to obtain the power versus distance relationship, the Cummulative Distribution Functions(CDFs) of rms Delay Spread(DS) and of the 3 dB frequency correlation band-width. Finally, the 3 dB width of the frequency correlation func-tion has been empirically related to the inverse of the rms DS of the impulse response.
Oh, Jun-Hak,Yoo, Byung-Gil,Choi, In-Chul,Santella, Michael L.,Jang, Jae-il Cambridge University Press (Materials Research Soc 2011 Journal of materials research Vol.26 No.10
<▼1><B>Abstract</B><P/></▼1><▼2><P>In this work, we have systematically explored the influence of thermo-mechanical treatment on the precipitation behavior and its strengthening in Inconel 740, a relatively new Ni-based superalloy, using specimens on which different levels of stresses were applied at 700 °C. With increasing applied stress, fraction of gamma prime precipitates increased (without significant size change) and nanoindentation hardness was enhanced. The stress effects were discussed in terms of the free energy barrier for heterogeneous nucleation and the prevailing mechanisms of precipitation strengthening.</P></▼2>