This paper studies simultaneous wireless information and power transfer (SWIPT) systems in two-way relaying (TWR) channels. Here, two source nodes receive information and energy simultaneously via power splitting (PS) from the signals sent by a multi-antenna relay node. Our objective is to maximize the weighted sum of the harvested energy at two source nodes subject to quality of service (QoS) constraints and the relay power constraints. Three well-known and practical two-way relay strategies are considered, i.e., amplify-andforward (AF), bit level XOR based decode-and-forward (DF-XOR) and symbol level superposition coding based DF (DF-SUP). For each relaying strategy, we formulate the joint energy transmit beamforming and PS ratios optimization as a nonconvex quadratically constrained problem. To find a closed-form solution of the formulated problem, we decouple the primal problem into two subproblems. In the first problem, we intend to optimize beamforming vector for a given PS ratio. In the second subproblem, we optimize the PS ratio with a given beamforming vector. It is worth noting that although the corresponding subproblem are nonconvex, the optimal solution of each subproblem can still be found by using certain techniques. We provide numerical results that demonstrate the advantage of adapting the different relaying strategies and weighted factors to harvest energy in two-way relaying channel.Index Terms-Beamforming, energy harvesting, simultaneous wireless information and power transfer (SWIPT), two-way relaying (TWR), power splitting (PS).

Rather crafty: 1,1-Difluoroallenes bearing an aryl group and a cyclopentene moiety undergo indium(III)-catalyzed Friedel-Crafts-type cyclization with subsequent ring expansion and dehydrogenation to afford fluorinated polycyclic aromatic hydrocarbons in high yields. The introduction of an Ar group was effected by in situ halogenation of the intermediary indium species and a subsequent Suzuki-Miyaura reaction.

Difluorinated polycyclic aromatic hydrocarbons (PAHs) containing three to five benzene rings were systematically synthesized by the Pd(II)-catalyzed Friedel-Crafts-type cyclization of 1,1,2trifluoro-and 1,1-difluoro-1-alkenes and the In(III)-catalyzed tandem cyclization of bis(1,1difluoroallene)s. Using an array of the difluorinated PAHs that were obtained and previously reported monofluorinated PAHs, the physical properties of the pinpoint-fluorinated PAHs were investigated. (i) The 19 F NMR signals of the bay-region fluorine atoms were shifted downfield by ca. 8-14 ppm for vicdifluorinated PAHs and ca. 11-19 ppm for non-vic-difluorinated and monofluorinated PAHs. (ii) The introduction of fluorine into PAH molecules increased their solubilities in organic solvents, which was best exemplified by the high solubilities of 6,7-difluoropicene (5.4 wt%) and 6-fluoropicene (5.3 wt%) in THF. (iii) The HOMO-LUMO energy gaps of the pinpoint-fluorinated PAHs were smaller than that

Diaryl thioethers can be prepared via a copper-catalyzed cross-coupling between aryl halides and thioacetamide using Cs 2 CO 3 as a base and DMSO-H 2 O as a solvent at 120°C.

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