The effects of boron addition on the heating processes of martensite in 0.1C-9Cr-3W-3Co steels have been studied. The steels with and without 100 ppm boron were prepared. The specimens were ...austenitized at 1200°C for 1.2 ks, and quenched into iced brine, resulting in formation of α' martensite laths. They were heated up to 1000°C at a rate of 10°C/min. Temperature derivative of electric resistivity, dρ/dT, decreased gradually around 500°C, increased slightly around 750°C, decreased around 810°C and largely decreased around 870°C in both steels. Observations by transmission electron microscopy revealed that the reactions were related to the formation of M7C3, dissolution of both cementite and M7C3, the precipitation of M23C6 and the austenite formation, respectively. The boron addition promotes M23C6 formation and retards the α→γ transformation.
The crystallography of the intermetallic phases forming at the zinc-film/substrate interfaces in hot-dip galvanizing steel sheets has been investigated mainly by means of scanning electron and cross ...sectional transmission electron microscopies. Zinc atoms penetrating into a ferrite lattice precipitate within the ferrite as monoclinic ζ-phase rods with parallelogram cross sections initially in contact with the interface. The growth direction of the ζ-phase rod is probably the 001ζ which lies parallel to a α. The orientation relationship between ζ and the substrate ferrite, 001ζ//111α, (100)ζ//(101)α, (010)ζ//(121)α, can be expected by considering both the results of scanning microscopy and the atomic configurations of ζ phase and those of ferrite. The additional heat cycle up to 723 K to produce thin foils for cross sectional transmission electron microscopy after the hot-dip galvanizing process induces the formation of δ1-phase at the ferrite/ζ interphase boundary. No specific orientation relationship between the δ1-phase and the substrate ferrite was obtained.
A 60-GHz RLSA fed by butler matrix carrying three OAM modes Xin Xu; Mori, Dan; Mazzinghi, Agnese ...
2017 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting,
2017-July
Conference Proceeding
We propose a 60-GHz radial line slot antenna (RLSA), which is fed by a Butler matrix, for orbital angular momentum (OAM) applications. The Butler matrix is placed at the lower layer and it is based ...on a post-wall waveguide structure. It has four input ports and it can launch different progressive phase states in the RLSA parallel plate waveguide (PPW). The RLSA in the upper layer is fed by the Butler matrix through four posts. The simulated results show that, at the design frequency, the proposed antenna can generate three OAM-mode states: l = 0, -1 and +1.
Zn/Ni alloy electrodeposition on a low carbon steel sheets has been examined by means of X-ray diffraction and scanning electron microscopy. With increasing current density, Ni content in a Zn/Ni ...film deposited decreases to a minimum value and then increases. This variation of Ni content in lower Ni baths corresponds to the morphological change of the deposits from granular η/γ mixed phases to layered hexagonal η-phase plates. But in the case of higher Ni baths, the deposited films comprise both η- and γ-phases, and the morphology varies from fine granular precipitates to large spherical particles consisting of granular precipitates. The c/a ratio of η-phase crystal varies from 1.87 to 1.75 with increasing the supersaturation of Ni atoms in η-phase deposits. The effects of quantity of electricity on Ni content of the deposits can be explained in terms of the variation of surface area of the deposits.
Recently, attention on wireless communications has been shifted from multiple-input multiple-output (MIMO) systems to multiuser MIMO (MU-MIMO) systems, which serve several users simultaneously in ...frequency and time. For a system with multiantenna users, block diagonalization (BD) is a technique, where multiuser interference can be completely canceled. For realizing the BD algorithm, the base station should know the accurate channel state information (CSI) of users. However, the CSI fed back to the base station becomes outdated due to the time-varying nature of the channels. Channel prediction is an efficient approach to combat the performance degradation due to feedback delay in single user MIMO system, but in a BD system, the multiuser interference will still remain. In this paper, we analyse the effects of the imperfect CSI caused by feedback delay on BD MIMO downlink system with channel prediction. The result is that the interference will be proportional to the mean square error (MSE) of predicted CSI. We also propose a robust scheme for this kind of systems.
To realize a voltage controlled oscillator (VCO) in wireless communications, a device is developed using a new tunable ring filter. The oscillator is based upon the tunable ring filter, with a ...compact and sharp rejection filter, high performance active inductor. It operates in the 3.2 GHz to 4.1 GHz frequency range. The VCO's phase noise level is -93dBc/Hz at 100kHz offset from a 3.5GHz carrier.
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