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Modular robots carry the unique advantage of changing their shape according to different tasks and environments. In order to study the lightweight and flexible combination characteristics of modular robots, this paper presents a two-degree-of-freedom pluggable modular robot and its simulation method, named SnackBot. SnackBot is composed of several independently operating modules. Each module contains a control unit, a micro battery, and two DC motors that drive the module joints. In order to predict robot actions and monitor the state of the robot, the simulation model of SnackBot is built and a virtual environment is established in Ignition Gazebo. The virtual robot and physical robot are synchronously controlled in the environment of the Robot Operating System 2 (ROS2). Finally, experimental results verify the feasibility of the SnackBot. [ABSTRACT FROM AUTHOR]

To establish a student-centered teaching quality assurance system in English teaching in universities, it is necessary to establish an educational philosophy of survival based on quality, achieve student-centered learning, optimize the allocation of English teaching resources, and reform evaluation standards; To address the problems in English teaching, we need to raise awareness of the construction of a "student-centered" teaching quality assurance system, carry out "student-centered" teacher training activities, and improve teachers' professional skills; At the same time, we will establish a student-centered English curriculum system, promote the reform and innovation of teaching models, establish a diversified English teaching evaluation system, and ensure the high efficiency and quality of English teaching in universities. The college English teaching quality evaluation is the MAGDM. Recently, the TODIM and MABAC technique has been employed to manage MAGDM. The interval-valued intuitionistic fuzzy sets (IVIFSs) are employed as a useful tool for portraying uncertain information during the college English teaching quality evaluation. In this paper, the interval-valued intuitionistic fuzzy TODIM-MABAC (IVIF-TODIM-MABAC) technique is built to manage the MAGDM under IVIFSs. At last, the numerical example for college English teaching quality evaluation is employed to show the IVIF-TODIM-MABAC decision technique. The main contribution of this paper is outlined: (1) the TODIM technique based on MABAC has been extended to IVIFSs based on Entropy technique; (2) the Entropy technique is employed to manage weight based on score values under IVIFSs. (3) the IVIF-TODIM-MABAC technique is founded to manage the MAGDM under IVIFSs; (4) a numerical example for college English teaching quality evaluation and some comparative analysis is supplied to verify the proposed technique. [ABSTRACT FROM AUTHOR]

The much thicker intrinsic absorption layer (IAL) in normal-incidence Ge-on-Si photodetectors (NIPD) usually causes a contradiction between responsivity and bandwidth. In response to this issue, here, we simulate the design of an NIPD with geranium (Ge) layers based on a "fishnet" metasurface, leading to a reduced device thickness as thin as 380 nm. The optical simulation results show that the light field can be perfectly localized in the 210 nm IAL, and the absorptivity is as high as 99.45% at 1550 nm, which is even better than bulk materials. Moreover, the electrical simulation results suggest that the horizontal size of the photosensitive region can be reduced to 11.2 μ m, while the responsivity of the photodetector is close to 1 A/W at −1 V bias voltage, which is nearly 23 times that of a bulk device with the same thickness, and the 3dB bandwidth is up to 40 GHz, which can be compared with waveguide photodetectors. Besides, this device also demonstrates a high signal-to-noise ratio with a low dark current of 28.68 nA, making it an excellent PD for opto-electrical communication. A photodetector with 210 nm germanium (Ge) "fishnet" metasurface was designed, with absorptivity as high as 99.45% at 1550 nm. The responsivity of the photodetector is close to 1 A/W at –1 V bias voltage, and the 3 dB bandwidth is up to 40 GHz. Besides, this device also demonstrates a high signal-to-noise ratio with a low dark current of 28.68 nA, making it an excellent PD for opto-electrical communication. [ABSTRACT FROM AUTHOR]

In this study, two NH4+-N and S2− removal strains, namely, Kosakonia oryzae (FB2-3) and Acinetobacter baumannii (L5-4), were isolated from the packing materials in a long-running biotrickling filter (BTF). The removal capacities of combined FB2-3 and L5-4 (FB2-3 + L5-4) toward 100 mg L−1 of NH4+-N and 200 mg L−1 of S2− reached 97.31 ± 1.62% and 98.57 ± 1.12% under the optimal conditions (32.0 °C and initial pH = 7.0), which were higher than those of single strain. Then, FB2-3 and L5-4 liquid inoculums were prepared, and their concentrations respectively reached 1.56 × 109 CFU mL−1 and 1.05 × 109 CFU mL−1 by adding different resuspension solutions and protective agents after 12-week storage at 25 °C. Finally, pilot-scale BTF test showed that NH3 and H2S in the real exhaust gases from a pharmaceutical factory were effectively removed with removal rates > 87% and maximum elimination capacities were reached 136 g (NH3) m−3 h−1 and 176 g (H2S) m−3 h−1 at 18 °C-34 °C and pH 4.0–7.0 in the BTF loaded with bamboo charcoal packing materials co-immobilized with FB2-3 and L5-4. After co-immobilization of FB2-3 and L5-4, in the bamboo charcoal packing materials, the new microbial diversity composition contained the dominant genera of Acinetobacter, Mycobacterium, Kosakonia, and Sulfobacillus was formed, and the diversity of entire bacterial community was decreased, compared to the control. These results indicate that FB2-3 and L5-4 have potential to be developed into liquid ready-to-use inoculums for effectively removing NH3 and H2S from exhaust gases in BTF. [ABSTRACT FROM AUTHOR]