The assessment of college and university counselors and student management team has been one of the important issues that colleges and universities are concerned about. This paper applies the group ...decision-making model to the assessment of college counselors’ student work, and establishes the group decision-making model of college counselors’ assessment work according to the actual work of counselors. Attitude consensus threshold is set, and ACT is combined with individual feedback parameters to realize the balance between individual minimum correction and group consistency. And the method of mutual evaluation and scoring by five appraisal subjects is used to construct Markov matrix, and then the limit distribution of the matrix is found through linear weighting. Finally, the appraisal of 105 counselors was empirically analyzed, and the group decision-making model was used to give practical significance to the five appraisal items, namely, sense of efficacy, dedication, leadership, innovativeness, and executive power, one by one. The results show that for the 205 college counselors tested in the appraisal, the mean value of the student management work ability index is 30.55, and the maximum value is 90.95, and the results of this appraisal pass the test and have practical reference significance.
Recent advances in gradient metasurfaces have shown that by locally controlling the bianisotropic response of the cells one can ensure full control of refraction, that is, arbitrarily redirect the ...waves without scattering into unwanted directions. In this work, we propose and experimentally verify the use of an acoustic cell architecture that provides enough degrees of freedom to fully control the bianisotropic response and minimizes the losses. The versatility of the approach is shown through the design of three refractive metasurfaces capable of redirecting a normally incident plane wave to 60°, 70°, and 80° on transmission. The efficiency of the bianisotropic designs is over 90%, much higher than the corresponding generalized Snell's law based designs (81%, 58%, and 35%). The proposed strategy opens a new way of designing practical and highly efficient bianisotropic metasurfaces for different functionalities, enabling nearly ideal control over the energy flow through thin metasurfaces.
Metasurfaces open up unprecedented potential for wave engineering using subwavelength sheets. However, a severe limitation of current acoustic metasurfaces is their poor reconfigurability to achieve ...distinct functions on demand. Here a programmable acoustic metasurface that contains an array of tunable subwavelength unit cells to break the limitation and realize versatile two‐dimensional wave manipulation functions is reported. Each unit cell of the metasurface is composed of a straight channel and five shunted Helmholtz resonators, whose effective mass can be tuned by a robust fluidic system. The phase and amplitude of acoustic waves transmitting through each unit cell can be modulated dynamically and continuously. Based on such mechanism, the metasurface is able to achieve versatile wave manipulation functions, by engineering the phase and amplitude of transmission waves in the subwavelength scale. Through acoustic field scanning experiments, multiple wave manipulation functions, including steering acoustic waves, engineering acoustic beams, and switching on/off acoustic energy flow by using one design of metasurface are visually demonstrated. This work extends the metasurface research and holds great potential for a wide range of applications including acoustic imaging, communication, levitation, and tweezers.
A programmable acoustic metasurface composed of fluid‐actuated tunable subwavelength unit cells is reported. All the unit cells can be dynamically and independently modulated through a robust fluidic system to achieve versatile functions, including steering acoustic waves, engineering acoustic beams, and switching on/off acoustic energy flow. The proposed metasurface offers a programmable, continuous, and efficient method for acoustic wave manipulation.
The valley degree of freedom in crystals offers great potential for manipulating classical waves, however, few studies have investigated valley states with complex wavenumbers, valley states in ...graded systems, or dispersion tuning for valley states. Here, we present tunable valley phononic crystals (PCs) composed of hybrid channel-cavity cells with three tunable parameters. Our PCs support valley states and Dirac cones with complex wavenumbers. They can be configured to form chirped valley PCs in which edge modes are slowed to zero group velocity states, where the energy at different frequencies accumulates at different designated locations. They enable multiple functionalities, including tuning of dispersion relations for valley states, robust routing of surface acoustic waves, and spatial modulation of group velocities. This work may spark future investigations of topological states with complex wavenumbers in other classical systems, further study of topological states in graded materials, and the development of acoustic devices.
The images acquired by a single visible light sensor are very susceptible to light conditions, weather changes, and other factors, while the images acquired by a single infrared light sensor ...generally have poor resolution, low contrast, low signal-to-noise ratio, and blurred visual effects. The fusion of visible and infrared light can avoid the disadvantages of two single sensors and, in fusing the advantages of both sensors, significantly improve the quality of the images. The fusion of infrared and visible images is widely used in agriculture, industry, medicine, and other fields. In this study, firstly, the architecture of mainstream infrared and visible image fusion technology and application was reviewed; secondly, the application status in robot vision, medical imaging, agricultural remote sensing, and industrial defect detection fields was discussed; thirdly, the evaluation indicators of the main image fusion methods were combined into the subjective evaluation and the objective evaluation, the properties of current mainstream technologies were then specifically analyzed and compared, and the outlook for image fusion was assessed; finally, infrared and visible image fusion was summarized. The results show that the definition and efficiency of the fused infrared and visible image had been improved significantly. However, there were still some problems, such as the poor accuracy of the fused image, and irretrievably lost pixels. There is a need to improve the adaptive design of the traditional algorithm parameters, to combine the innovation of the fusion algorithm and the optimization of the neural network, so as to further improve the image fusion accuracy, reduce noise interference, and improve the real-time performance of the algorithm.
Abstract
Knots and links have been conjectured to play a fundamental role in a wide range of scientific fields. Recently, tying isolated vortex knots in the complex optical field has been realized. ...However, how to construct the acoustic vortex knot is still an unknown problem. Here we propose theoretically and demonstrate experimentally the creation of acoustic vortex knots using metamaterials, with decoupled modulation of transmitted phase and amplitude. Based on the numerical simulation, we find that the knot function can be embedded into the acoustic field by designed metamaterials with only 24 × 24 pixels. Furthermore, using the optimized metamaterials, the acoustic fields with Hopf link and trefoil knot vortex lines have been observed experimentally.
This mixed-methods national study has a two-fold purpose: (a) to invite Chinese college students to rate their overall difficulties in the eight areas of English learning, i.e., listening, speaking, ...reading, writing, pronunciation, grammar, vocabulary, and culture; and (b) to invite them to identify their key challenges in learning EFL. Specifically, the following three research questions were asked: (a) what are their overall difficulties in the eight areas of learning EFL? (b) Are there significant differences in rating their overall difficulties in these eight areas across the demographic variables of gender (i.e., male versus female participants) and subject discipline (arts versus sciences versus English subject disciplines participants)? And (c) what are their key challenges in learning EFL?
The participants included a sample of 1,525 freshmen and sophomore students currently studying at seven universities across China. The instrument was a survey that consisted of a five-point Likert scale self-evaluation form and a major essay question addressing their key challenges. The qualitative data can help to probe deeply into the research setting to obtain in-depth understandings about Chinese college students' English learning; and therefore, they can greatly enhance the quantitative data.
The quantitative results indicated that listening, speaking, and writing were their three key difficult areas in EFL learning; further, students' subject discipline (arts versus sciences verse English subject disciplines) had significant effects on their perceived learning challenges in English listening and vocabulary. The qualitative results confirmed that listening, speaking, and writing were their three key challenging areas. Their specific learning challenges in each area were examined. Implications for Chinese college English teachers and administrators are discussed in terms of pedagogy and policy making, respectively.
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