Beam Management for Millimeter Wave Beamspace MU-MIMO Systems

Millimeter wave (mmWave) communication has attracted increasing attention as a promising technology for 5G networks. One of the key architectural features of mmWave is the use of massive antenna arrays at both the transmitter and the receiver sides. Therefore, by employing directional beamforming (BF), both mmWave base stations (MBSs) and mmWave users (MUEs) are capable of supporting multi-beam simultaneous transmissions. However, most researches have only considered a single beam, which means that they do not make full potential of mmWave. In this context, in order to improve the performance of short-range indoor mmWave networks with multiple reflections, we investigate the challenges and potential solutions of downlink multi-user multi-beam transmission, which can be described as a high-dimensional (i.e., beamspace) multi-user multiple-input multiple-output (MU-MIMO) technique, including multi-user BF training, simultaneous users' grouping, and multi-user multibeam power allocation. Furthermore, we present the theoretical and numerical results to demonstrate that beamspace MU-MIMO compared with single beam transmission can largely improve the rate performance of mmWave systems.Comment: The sixth IEEE/CIC International Conference on Communications in China (ICCC2017

Study on fault mechanism of shaft hoist steelwork

AbstractSome achievements have been made in detecting the vibration faults in shaft hoist steelwork, but very little information is currently available to help study the faults mechanism. The faults during the run-ups stage are different from the faults during even speed stage. This paper deals with the fault mechanism through establishing the vibration model as the conveyance moves in shaft. By simulation we can see different vibrating instances correspond to different steelwork faults, and then we put forward suitable fault diagnosis methods

Chk1/2 inhibitor AZD7762 blocks the growth of preantral follicles by inducing apoptosis, suppressing proliferation, and interfering with the cell cycle in granulosa cells

Background. Checkpoint kinases 1/2 (Chk1/2) have an important role in somatic cell development and oocyte meiotic maturation. However, the role of Chk1/2 in folliculogenesis has not been fully elucidated. The aim of this study was to assess the effects of Chk1/2 inhibition on ovarian folliculogenesis and granulosa cell development in mice. Methods. Preantral follicles (100-120 μm) and granulosa cells from pre-ovulatory follicles (pre-GCs) of mice were isolated and cultured with or without Chk1/2 inhibitor AZD7762. Preantral follicles were cultured for 96h. Then, follicle morphology and follicular growth were assessed every 48h. Granulosa cells were cultured for 48h with or without AZD7762, after which cell apoptosis, cell proliferation, and cell cycle analysis were assessed; meanwhile, the mRNA expression of PCNA and Bax were measured by real-time RT-PCR, and PCNA and Bax protein were measured by Western blot. Results. Compared with control follicles, AZD7762 inhibited growth of preantral follicles (P<0.05). Furthermore, inhibition of Chk1/2 significantly induced apoptosis (P<0.05) and inhibited the proliferation of granulosa cells (P<0.01), arrested cell cycle at S and G2/M phases, and decreased G1 phase fraction (P<0.001). Also, the expression of PCNA mRNA and protein were reduced (P<0.01), while Bax mRNA and protein were increased (P<0.05) post AZD7762 treatment in granulosa cells. Conclusions. This study revealed that Chk1 and Chk2 have a crucial role during preantral follicular development by regulating the proliferation and apoptosis of granulosa cells

(4-Carb­oxy-2-sulfonato­benzoato-κ2 O 1,O 2)bis­(1,10-phenanthroline-κ2 N,N′)manganese(II)

In the title complex, [Mn(C8H4O7S)(C12H8N2)2], the MnII atom is chelated by one 4-carb­oxy-2-sulfonato­benzoate anion and two phenathroline (phen) ligands in a distorted octa­hedral MnN4O2 geometry. The benzene ring of the 4-carb­oxy-2-sulfonato­benzoate anion is twisted with respect to the two phen ring systems at dihedral angles of 66.38 (9) and 53.56 (9)°. In the crystal, inter­molecular O—H⋯O and C—H⋯O hydrogen bonding links the mol­ecules into chains running parallel to [100]. Inter­molecular π–π stacking is also observed between parallel phen ring systems, the face-to-face distance being 3.432 (6) Å