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In order to solve the problem of all-optical communication network capacity and spectral efficiency, a two-cavity six-channel Wavelength Division Multiplexer (WDM) based on the coupling characteristics of point-defect cavity and line-defect waveguide of Two-Dimensional (2-D) photonic crystal is proposed in this paper. 2-D finite-difference time-domain method is used to analyze the performance parameters. Considering the influence of relative refractive index, the coupling mode of double resonators and single straight waveguide is selected to achieve the wavelength division multiplexing of 1 451, 1 487, 1 557, 1 658, 1 440 and 1 604 nm. The results show that the multiplexer has a spectral coverage of up to 218 nm, transmission efficiency of each channel higher than 91%, the insertion loss less than 0.43 dB, the cross-talk between channels less than -9.2 dB, and the size of only 13.56 μm×19.21 μm. It is very useful for coarse wavelength division multiplexing in optical communication systems, which also has reference significance for dense wavelength division multiplexing.

In order to improve the corrosion resistance of anticorrosive coatings and expand the application scope of Iranian rock asphalt, solentless Iranian rock asphalt anticorrosive coatings were prepared throuth a two-component process using the matrix asphalt, Iranian rock asphalt and epoxy resin as film - forming materials with the addtion of fillers, various additives and other components. The anti - corrosion properties of such coatings were studied through AC impedance test and acid, alkali and salt corrosion resistance test. Results showed that when the content of Iranian rock asphalt was 15%, the comprehensive properties of modified asphalt were best. The corrosion resistance of the prepared Iranian rock asphalt anticorrosive coating was much better than that of the petroleum asphalt anticorrosive coating. The corrosion resistance time to acid, alkali and salt immersion was prolonged by more than 10 days. The viscosity of Iranian rock asphalt anticorrosive coating was large at room temperature, and good coating effect was achieved when the coating temperature was about 60 ℃.

The development of science and technology (sci-tech) finance is conducive to improving the transformation quality of sci-tech achievements and optimizing the allocation of resources. However, the current sci-tech finance field in China is mainly promoted by the way of government work, and the theoretical research on the operation mechanism and system structure of sci-tech finance is relatively lagging. This article constructs the research framework of the sci-tech financial ecosystem from the perspective of ecology, uses the quantitative method of index design to deconstruct the gap between China and other major countries in the world, and analyzes the reasons and enlightenment. It is expected to provide decision-making support for relevant policies from the perspective of top-level design while promoting theoretical research.

A computer-vision-based method is widely employed to support the development of a variety of applications. In this vein, this study uses a computer-vision-based method to develop a playful learning system, which is a robot-based learning companion named RobotTell. Unlike existing playful learning systems, a user-centered design (UCD) approach is applied to assess the interface design of the RobotTell System so that the human-robot interaction can be enhanced during the design process. More specifically, the interface of the RobotTell system is assessed based on Nielsen's heuristics. Based on the results of Nielsen's heuristic evaluation, three versions of the RobotTell system were produced. The implications for the design of these three versions of the RobotTell system are discussed.

Multimodal learning analytics (MMLA), which has become increasingly popular, can help provide an accurate understanding of learning processes. However, it is still unclear how multimodal data is integrated into MMLA. By following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, this paper systematically surveys 346 articles on MMLA published during the past three years. For this purpose, we first present a conceptual model for reviewing these articles from three dimensions: data types, learning indicators, and data fusion. Based on this model, we then answer the following questions: 1. What types of data and learning indicators are used in MMLA, together with their relationships; and 2. What are the classifications of the data fusion methods in MMLA. Finally, we point out the key stages in data fusion and the future research direction in MMLA. Our main findings from this review are (a) The data in MMLA are classified into digital data, physical data, physiological data, psychometric data, and environment data; (b) The learning indicators are behavior, cognition, emotion, collaboration, and engagement; (c) The relationships between multimodal data and learning indicators are one-to-one, one-to-any, and many-to-one. The complex relationships between multimodal data and learning indicators are the key for data fusion; (d) The main data fusion methods in MMLA are many-to-one, many-to-many and multiple validations among multimodal data; and (e) Multimodal data fusion can be characterized by the multimodality of data, multi-dimension of indicators, and diversity of methods.