Volume 143

Low-altitude economy has prompted low-altitude transportation, a new public transportation mode, to bring new changes to citizens' daily travel. Low-altitude transportation has broad prospects. In low-altitude airspace, aircraft are used as vehicles to cover low-altitude flight activities such as manned and cargo. It has the advantages of alleviating ground traffic congestion and improving travel efficiency. The development of low-altitude transportation faces many challenges, such as inaccurate airspace resource management and lack of coordination in the life cycle of the entire industrial chain. Therefore, it is crucial to promote the reform of the management system of the entire civil aviation industry, accelerate the implementation of airspace classification management, improve service guarantee quality, and improve the service system for low-altitude flight activities. And with the help of big data analysis and artificial intelligence technology, optimize flight paths, improve flight efficiency, and reduce operating costs. Although facing many challenges, with policy support, technological innovation, and management optimization, low-altitude transportation is expected to be widely used and developed, injecting new vitality into the public transportation system. This article mainly discusses the integrated development of low-altitude transportation in the public transportation system, analyzes its definition, characteristics, application status and proposes optimization strategies for airspace management, technical bottlenecks, laws and regulations, and other restrictive factors. This article provides theoretical basis and practical reference for the future development of low-altitude transportation, promotes the healthy and sustainable development of low-altitude transportation, and brings changes to urban transportation.

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In recent years, precision motion systems have played an increasingly important role in scientific research and engineering applications. Among them, compliant mechanisms are typical enabling components for precise motion. Establishing models for compliant mechanisms is crucial for their design and analysis. In this paper, stiffness modeling is conducted for four typical compliant mechanisms: single parallelogram compliant mechanisms, mirrored single parallelogram compliant mechanisms, double parallelogram compliant mechanisms, and mirrored double parallelogram compliant mechanisms. To validate the accuracy of the proposed models, three-dimensional models of the compliant mechanisms were constructed using UG software, and finite element analysis (FEA) was performed using ANSYS software. The results demonstrate that the deviation between the theoretical stiffness and simulated stiffness of the four compliant mechanisms is less than or equal to 3.5%. The stiffness models developed for the compliant mechanisms lay a foundation for the design of complex compliant motion systems.

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At present, the new scientific and technological reform in the world is having a tremendous impact on the transportation industry, and the future development direction of the transportation field is the focus of the current research. In this context, Australia's transportation system is also in an important period of transformation in the direction of on-demand, low-carbon, network connection and automation. This paper studies and discovers Australia's existing achievements and problems in the field of transportation from three aspects: transport services, transport management and transport policy. Facing the development direction of Australian future transportation, the paper studies the strategic deployment, advantages and disadvantages, and upcoming challenges of Australian future transportation from the two main aspects of self-driving cars and intelligent transportation systems. In the aspect of building a powerful transportation country, learning and accepting the strategies of other countries with an open mind and continuously studying the ideas and progress of other countries in solving traffic problems can contribute to the construction and development of transportation in our country.

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Fabric softeners play a pivotal role in maintaining clothing's comfort and softness. In modern formulations, cationic surfactants are commonly employed. However, both the manufacturing process and the final products of this industry have raised significant concerns leaving ample room for enhancement. The disposal of surfactants can cause damage to the environment and affect the health of organisms. Furthermore, the current fabric softeners also have side effects on the comfort of the apparel, such as causing skin irritation and making the clothes less thermally comfortable. This paper is dedicated to summarizing the mechanism of surfactants, analyzing the strengths and weaknesses of current products, and exploring the feasibility of using esterquats as an alternative. Through a concise literature review, this paper uncovers an area of uncertainty in the theories regarding how surfactants function. It also reveals the benefits of esterquats, such as biodegradability and flexibility, along with some lingering doubts. This paper concludes that there needs to be further research regarding the properties of esterquats to fill up the current literature gap as well as the potentialities of using other types of surfactants to substitute cationic surfactants in the production of fabric softeners.

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Tungsten and its compound, tungsten carbide, play significant roles in aerospace, aviation and friction welding fields. Through a systematic review and analysis of the literature, this paper summarizes the friction and wear characteristics of pure tungsten coatings from room temperature to high temperatures, the evolution of their microstructure, and the changes in tribological properties because of the formation of oxide films caused by alterations in the surrounding chemical environment at high temperatures. For tungsten carbide coatings, this paper summarizes their friction and wear processes, the formation of mechanically mixed layers, and their friction response in different environments (dry and lubricated)This research investigates the variation in the friction coefficient of pure tungsten across a temperature range from ambient conditions to over 1000℃, highlighting inconsistent trends between room temperature and 600℃. Additionally, the study addresses ongoing debates and outlines potential avenues for future research on pure tungsten and its composite coatings.

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Superhydrophobic materials can realize the effective slippage of liquid on the surface, a with excellent properties such as self-cleaning and anti-pollution, they can be widely used in liquid transportation, anti-pollution coatings, microfluidic transport and other fields. In nature, organisms have evolved many special structures that adapt to their living environment, such as lotus leaves, water striders and other organisms with unique micro and nano structures, showing amazing water-repellent and self-cleaning properties. By studying and mimicking the microstructure of these biological surfaces, scientists have successfully prepared surfaces with excellent superhydrophobic microstructures. The paper will discuss the mechanism of superhydrophobic phenomena and introduce the applications of superhydrophobic materials in anti-icing, anti-oil, anti-fogging and self-cleaning. Finally, by reading the relevant literature, this paper discusses the future development of superhydrophobic materials, the preparation process of superhydrophobic surfaces is still relatively complex, and how to maintain the stability and hydrophobicity of the surface while simplifying the hydrophobic preparation steps is a key challenge for researchers.

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Proteinogenic amino acids – the primary monomers to form proteins on Earth – have been found successively in extraterrestrial areas over decades. It was reported that the detection of amino acids can be both ex situ and in situ. The discovery of proteinogenic amino acids from space may date back to the history of the solar system and is suggestive of alternative mechanisms of synthesizing amino acids. This article uses the literature review method and systematically summarizes the findings from meteorites, asteroids, comets, and the interstellar medium. The article concludes that complex organic molecules are widely spread across the universe and supports the hypothesis that the basic building block of life may be delivered to Earth via celestial bodies, increasing the likelihood of searching for living organisms outside Earth.

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