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The assessment and comparison of the S&T innovation competitiveness among the provinces and regions in the Yellow River Basin are helpful to better utilize the supporting and leading role of S&T innovation in the ecological protection and high-quality development of the Yellow River Basin. Combined with the real characteristics of S&T innovation in the Yellow River Basin, the study considers five dimensions horizontally: S&T innovation input, S&T innovation output, S&T entrepreneurial condition, S&T innovation revenue, and S&T innovation influence. Vertically, it considers two types of indicators, namely, strength and efficiency, and constructs the index system of evaluation of S&T innovation competitiveness in the Yellow River Basin. A multi-dimensional indicator system for measuring the competitiveness of S&T innovation in the Yellow River Basin is constructed, taking into account the differences in scale and efficiency indicators. Based on this, the study analyzes the evolution trend and current situation of S&T innovation competitiveness of the nine provinces and regions in the Yellow River Basin from 2012 to 2021, and further compares the differences in S&T innovation competitiveness among the provinces and regions in the Yellow River Basin. The study finds the followings. (1) The nine provinces and regions in the Yellow River Basin have formed three echelons with significant differences in the level of S&T innovation competitiveness, and the upstream provinces and regions lag behind noticeably in S&T innovation competitiveness. (2) The evaluation results of five horizontal dimensions show that the low level of S&T entrepreneurship conditions and S&T innovation benefit are the key factors constraining the S&T innovation competitiveness of all provinces and regions in the Yellow River Basin. (3) The results of vertical "strength-efficiency" evaluation show that Shandong Province, which is in the first echelon of S&T innovation competitiveness in the Yellow River Basin, should focus on improving its competitive effectiveness in S&T innovation, while the provinces and regions in the third echelon (Inner Mongolia, Qinghai, Gansu, Shanxi, and Ningxia) should optimize their competitive strength in S&T innovation. Finally, the study proposes countermeasures to improve the competitiveness of S&T innovation in the Yellow River Basin. [ABSTRACT FROM AUTHOR]

The foundation for ecological protection and high-quality development in the Yellow River Basin lies in the rational development of industry. This study systematically analyzes the current state of industrial development in the Yellow River Basin, examining traditional industries, strategic emerging industries, and future industries. Based on this analysis, it identifies key issues and development directions. The study reveals that the industrial structure in the Yellow River Basin is unreasonable; traditional industries have short chains and high energy consumption; the cultivation of strategic emerging industries is inadequate and poorly aligned; and comprehensive planning for future industries is inadequate. Therefore, it is imperative to systematically optimize the industrial structure in the Yellow River Basin, promote the transformation and upgrading of traditional industries, accelerate the cultivation of strategic emerging industries through technological innovation, and plan the development of future industries from a holistic perspective. This approach will enhance the momentum and vitality necessary for advancing ecological protection and high-quality development in the Yellow River Basin, contributing to a new chapter in the western development. [ABSTRACT FROM AUTHOR]

Silicon carbide (SiC) is utilized in the automotive, semiconductor, and aerospace industries because of its desirable characteristics. Nevertheless, the traditional machining method induces surface microcracks, low geometrical precision, and severe tool wear due to the intrinsic high brittleness and hardness of SiC. Femtosecond laser processing as a high-precision machining method offers a new approach to SiC processing. However, during the process of femtosecond laser ablation, temperature redistribution and changes in geometrical morphology features are caused by alterations in carrier density. Therefore, the current study presented a multi-physics model that took carrier density alterations into account to more accurately predict the geometrical morphology for femtosecond laser ablating SiC. The transient nonlinear evolutions of the optical and physical characteristics of SiC irradiated by femtosecond laser were analyzed and the influence of laser parameters on the ablation morphology was studied. The femtosecond laser ablation experiments were performed, and the ablated surfaces were subsequently analyzed. The experimental results demonstrate that the proposed model can effectively predict the geometrical morphology. The predicted error of the ablation diameter is within the range from 0.15% to 7.44%. The predicted error of the ablation depth is within the range from 1.72% to 6.94%. This work can offer a new way to control the desired geometrical morphology of SiC in the automotive, semiconductor, and aerospace industries. [ABSTRACT FROM AUTHOR]

Silicon carbide (SiC) is a promising semiconductor material as well as a challenging material to machine, owing to its unique characteristics including high hardness, superior thermal conductivity, and chemical inertness. The ultrafast nature of femtosecond lasers enables precise and controlled material removal and modification, making them ideal for SiC processing. In this review, we aim to provide an overview of the process properties, progress, and applications by discussing the various methodologies involved in femtosecond laser processing of SiC. These methodologies encompass direct processing, composite processing, modification of the processing environment, beam shaping, etc. In addition, we have explored the myriad applications that arise from applying femtosecond laser processing to SiC. Furthermore, we highlight recent advancements, challenges, and future prospects in the field. This review provides as an important direction for exploring the progress of femtosecond laser micro/nano processing, in order to discuss the diversity of processes used for manufacturing SiC devices. [ABSTRACT FROM AUTHOR]

Femtosecond laser processing technology offers a promising technique for the preparation of micro and nanostructures of single-crystal silicon carbide (SiC), thanks to its high precision and non-destructive processing. However, further research is needed to optimize processing parameters, as well as improve efficiency and quality of the process. This study conducts experiments to explore the effects of femtosecond laser ablation on single-crystal SiC. The influence and significance of parameters, such as fluence (F), repetition rate, scan speed (S), multipass scanning (c) and numerical aperture on the performance of grooves, including groove depth, groove width, heat-affected zone (HAZ) width, material removal rate (MRR) and side wall inclination angle, were studied. The results show that the influence of fluence and numerical aperture on groove depth, groove width, HAZ width, MRR and side wall inclination angle is very significant. The scan speed has a very significant effect on the groove depth, groove width, HAZ width and side wall inclination angle but has insignificant effect on the MRR. Repetition rate and multipass scanning have a very significant effect on groove depth, HAZ width, MRR and side wall inclination angle and a moderately significant effect on groove width. The experimental methods of increasing the aspect ratio and reducing the HAZ width were studied, and a significance analysis was carried out. Fluence, multipass scanning and z-layer feed have significant effects on groove depth, groove width, aspect ratio, HAZ width and MRR. The influence of polarization angle on groove depth, groove width, aspect ratio and MRR is insignificant. [ABSTRACT FROM AUTHOR]