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Lumped passive elements are usually lossy because parasitic resistances dissipate the power transferred from the source to the load; thus, this loss influences the performance of the matching network. Furthermore, the impedances that need to be matched are usually complex‐valued. In this paper, we described an optimization design method for lossy three‐element network to achieve impedance matching between complex source and load impedances. We first determined the efficiency formulas for lossy Π and T networks via a generalized quality‐based equation. Next, two methods were introduced to design the lossy Π and T networks with maximum efficiency. Finally, to validate the effectiveness of the designed lossy three‐element networks, we conducted a series of numerical analysis and simulations, which indicates that the designed lossy Π and T networks exhibits excellent impedance matching performance at the desired frequency. For some instances, the lossy Π network with three elements exhibits a higher efficiency than a multistage matching network with more elements. [ABSTRACT FROM AUTHOR]

This paper investigates the fixed-time trajectory tracking control for a group of nonholonomic mobile robots, where the desired trajectory is generated by a virtual leader, the leader's information is available to only a subset of the followers, and the followers are assumed to have only local interaction. According to fixed-time control theory and adding a power integrator technique, distributed fixed-time tracking controllers are developed for each robot such that all states of each robot can reach the desired value in a fixed time. Moreover, the settling time is independent of the system initial conditions and only determined by the controller parameters. Simulation results illustrate and verify the effectiveness of the proposed schemes. [ABSTRACT FROM AUTHOR]

An efficient method for the selective C‐difluoromethylation of carbon acids with the reagent TMSCF2Br has been developed. A variety of structurally diverse sp3‐ and sp‐hybridized carbon nucleophiles, including esters, amides, fluorenes, terminal alkynes, β‐ketoesters, malonates, and other activated C−H nucleophiles, could be efficiently and selectively transformed into the corresponding C‐difluoromethylated products under mild conditions. This protocol is also effective for the late‐stage difluoromethylation of pharmaceutically relevant molecules and can be readily scaled up. Moreover, ambident substrates with more than one reactive site towards difluorocarbene can be difluoromethylated orthogonally using TMSCF2Br. [ABSTRACT FROM AUTHOR]

Abstract: A highly efficient copper‐mediated aromatic pentafluoroethylation method using TMSCF3 as the sole fluoroalkyl source is described. The reaction proceeds by a key C1 to C2 process, that is, the generation of CuCF3 from TMSCF3, followed by a subsequent spontaneous transformation into CuC2F5. Various aryl iodides were pentafluoroethylated with the TMSCF3‐derived CuC2F5. This method represents the first practical and efficient method for pentafluoroethylation of aryl iodides using commercially available TMSCF3 as a pentafluoroethyl precursor. [ABSTRACT FROM AUTHOR]

This paper is devoted to the event-triggered $$H_{\infty }$$ static output feedback control of linear discrete-time networked control systems. With the help of zero-holder, a time-delay formulation is adopted to describe the even-triggered output. Resorting to Finsler lemma and time-delay techniques, a co-design framework of event-triggering communication and static output controller is established in terms of linear matrix inequalities. Meanwhile, the required $$H_\infty $$ performance could be ensured by the proposed framework. Two examples are supplied to verify the validity of the proposed method. [ABSTRACT FROM AUTHOR]

A new method for the on-site preparation of tetrafluoroethylene (TFE) and a procedure for its efficient use in pentafluoroethylation by fluoride addition were developed by using a simple two-chamber system. The on-site preparation of TFE was accomplished by dimerization of difluorocarbene derived from (trifluoromethyl)trimethylsilane (TMSCF3) under mild conditions. Other fluoroalkylation reactions, such as (aryloxy)tetrafluoroethylation and tetrafluoroethylation processes, were also achieved using a similar approach. This work not only demonstrates a convenient and safe approach for the generation and use of TFE in academic laboratories, but also provides a new strategy for pentafluoroethylation. [ABSTRACT FROM AUTHOR]

A general method for the efficient difluoromethylation of alcohols using commercially available TMSCF2Br (TMS=trimethylsilyl) as a unique and practical difluorocarbene source is developed. This method allows primary, secondary, and even tertiary alkyl difluoromethyl ethers to be synthesized under weakly basic or acidic conditions. The reaction mainly proceeds through the direct interaction between a neutral alcohol and difluorocarbene, which is different from the difluoromethylation of phenols. Moreover, alcohols containing other moieties that are also reactive toward difluorocarbene can be transformed divergently by using TMSCF2Br. This research not only solves the synthetic problem of difluorocarbene-mediated difluoromethylation of alcohols, it also provides new insights into the different reaction mechanisms of alcohol difluoromethylation and phenol difluoromethylation with difluorocarbene species. [ABSTRACT FROM AUTHOR]