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Weight Fair Queuing is an ideal scheduling algorithm to guarantee the bandwidth of different queues according to their configured Weights when the switching nodes of the network are congested. Many of the switching nodes based on FPGA in the current network support four physical ports or hundreds of virtual ports. Massive logic and storage resources would be consumed if each port implemented a WFQ scheduler. This paper proposes a Queue-Group-Based WFQ Scheduler (QGWFQS), which can support WFQ scheduling across multiple ports through the reuse of tag calculation and encoding circuits. We also propose a novel finish tag calculation algorithm to accommodate the variation in the link rate of each port. The remainder of integer division is also taken into account, which makes the bandwidth allocation fairer. Experimental results show that the proposed scheduler supports up to 512 ports, with 32 queues allocated on each individual port. The scheduler has the capability to operate at 200 MHz and the total scheduling capacity reaches 200 Mpps. [ABSTRACT FROM AUTHOR]

At present, most of the space-borne atomic clocks used by the major global navigation satellite systems include rubidium atomic clocks, passive hydrogen master (PHM) clocks and cesium atomic clocks. The new independently developed space-borne rubidium atomic clocks and PHM clocks on BeiDou Global Navigation Satellite System (BDS-3) are important hardware improvements. In this paper, performances of new Beidou domestic atomic clocks are evaluated using precise clock offset data from September 2019 to September 2021 and compared with the mainstream space-borne atomic clocks of other satellite navigation systems. The results show that the BDS-3 space-borne PHM clocks have low drift rate and high stability at 86400s interval, which respectively reaches 8.26 × 10−16 and 5.13 × 10−15. These performances are only slightly lower than Galileo PHM clocks. The frequency stability at 86400s interval of BDS-3 rubidium clock is up to 9.03 × 10−15, which is 27.76% higher than GPS rubidium clocks. [ABSTRACT FROM AUTHOR]

In order to deal with the increasingly serious environmental problems, it is important and necessary to lower the concentration of greenhouse gases, especially the CO2 gas. CO2 capture and storage are the relative suitable options for the reduction of these harmful gas concentration. Through the variation of mass ratio of KOH to bio-char, the as prepared active carbon PC-4 exhibits a higher specific surface area of 2 491.57 cm3·g−1, with the ultra-micropores of 0.5 and 1.2 nm. At 298 K/1 bar, the CO2 adsorption capacity of PC-4 also represents the highest value of 5.81 mmol/g. This work demonstrates that the both the pore size and the specific surface area are equally important to enhance the CO2 adsorption. This work provides a sustainable method to develop high efficiency waste-based adsorbents to deal with environmental issues of CO2 gas. [ABSTRACT FROM AUTHOR]