Some critical aspects of metaverse are briefed. The significance of immersion to metaverse is highlighted. Efforts to improve the sense of immersion are investigated. The principles of some immersive display technologies including head-mounted display (HMD), head-up display (HUD) and large size display are introduced and the corresponding prospects are envisioned. The importance of immersive interaction on metaverse is analyzed. Values of computer graphics, artificial intelligence and machine vision for metaverse are induced. The potential applications of metaverse are predicted based on the mentioned features.

As Moore's law approaches to the limit, "More than Moore" for 2.5D/3D packaging is entering its historical arena. Through silicon via (TSV) is one of the important representatives in high-end electronics advanced packaging. This paper focuses on the copper plating process which realizes electrical interconnection in TSV technology and systematically summarizes the composition of the formula of copper plating solutions. The key difficulty of the copper plating process lies in the defect-free filling of TSV, and the selection of additives is particularly important. A guide for selection of electroplating solution for TSV metallization electroplating process is then provided. In addition, the external electric field and other process conditions imposed on the plating solution during the plating process will also affect the quality of filling vias. Therefore, TSV copper plating processes of the research teams at home and abroad are summarized for selection of a copper plating process. Finally, the characterization methods for studying the action mechanism of additives in electroplating solutions based on computational simulation and electrochemical testing are briefly summarized, and the progress and shortcomings of current research methods on additives in electroplating solution are discussed.

Large-scale adoption of composite blades is the most effective way to achieve ultra-high bypass ratio and low weight of aero-engine in the aerospace industry. The research progress in the manufacturing technology for resin matrix, metal matrix, and ceramic matrix composite blades is discussed in this paper. The development and application situation of the common processing technology and key manufacturing technology of aero-engine composite blades are reviewed in detail, including prepreg/molding process and three-dimensional braided/reinforced resin transfer molding process of resin matrix composite blades, molding process, pressure casting process and superplastic forming/diffusion bonding process of metal matrix composite blades, and melt infiltration process of ceramic matrix composite blades. Finally, the trend of aero-engine composite blades is discussed and the research direction to further develop key manufacturing technology of composite blades is summarized.

Additive manufacturing technology can break through the processing and design limitations of traditional processes and realize integrated forming of high-performance parts with complex structures. It has great application potential in aero engines and gas turbines. In this paper, for three types of alloys, including nickel-based superalloys, titanium-based alloys, and high-strength steels, the microstructure characteristics and control methods of laser processing parameters, composition modification, and external field are reviewed at first. Then the typical characteristics and comparison of mechanical properties are summarized, which provide an in-depth understanding of the mapping relationship between process parametersmicrostructure-mechanical properties of additive manufacturing alloys. Finally, the application status and typical cases of additive manufacturing of the above materials in key components are introduced. In addition, this paper also looks ahead at the new additive manufacturing technology, microstructure control technology, special alloy composition, and research on the process stability for key components in the field of aero engines and gas turbines, which can further promote the application of additive manufacturing technology.

Developing new energy vehicles and promoting industrialization of new energy vehicles are of great significance for solving the problems of high pollution, high energy consumption, and high emissions of traditional fuel vehicles. Taking new energy vehicle as the research object this paper comprehensively analyzes the current industrial and technological development status of new energy vehicles from the development background of new energy vehicles, the whole vehicle, and the three-electric system. It is pointed out that Chian's new energy vehicles have issues such as imperfect infrastructure construction, low battery recycling rate, and lack of mastery of key technologies of basic devices. Therefore, this paper aims to provide reference for the future development direction and planning of new energy vehicle technology and industry.

Based on the realistic requirements of "double carbon" goal for the green development of the construction industry,this paper analyzes the low-carbon development experience of construction industry in the major developed countries and the low-carbon development trend of China's construction industry. Combined with the important opportunities brought by intelligent construction for the green and low-carbon transformation, this paper proposes the path of green and low-carbon transformation for the construction industry in the context of intelligent construction from four dimensions: architectural design, building materials production, building construction, and smart operation, and puts forward the policy suggestions in the context of intelligent construction from four aspects: strengthening top-level system design, improving the supporting policy system, accelerating the innovative development of enterprises and building a healthy industrial ecology. The paper may provide reference for implementing the manufacturing power strategy and the continuous promotion of high-quality development of construction industry of China in the new era.

On the basis of analyzing the connotation, system architecture, typical characteristics and main classifications of advanced manufacturing technology, the paper systematically summarizes the technological innovation paths and technological advantages of advanced manufacturing industries at home and abroad, such as the United States, Germany, Japan and China. Under the background of promoting the construction of a manufacturing power, and in combination with the world development trends, the paper puts forward suggestions for the high-quality development of China's advanced manufacturing industry in terms of promoting intelligent manufacturing, strengthening basic scientific research, laying out internationally leading state laboratories and innovation centers, and building an independent leading manufacturing industry cluster, with a view to providing theoretical and practical reference for domestic scholars in this field.

For the past decade the study of the ship domain theory has made great progress and been widely used in the research of ship collision avoidance, navigation decision-making and marine traffic engineering. With the rising of the concept of MASS (maritime autonomous surface ship) and relevant laws/regulations, the process of ship intelligence and autonomy will be accelerated, and the ship domain theory will develop in a new direction under this trend. The main motivation of this paper is to explore the role of ship domain in the development of autonomous vessels. Firstly, the development status of the ship domain is summarized including existing definitions and modeling methods, and the practical application scenarios of the ship domain models are discussed. Subsequently, the development of MASS and the challenges it may face in the future innovation process are discussed. Finally, according to the needs of the MASS era, the future development direction and application of the ship domain theory are put forward.

The redefinition of the International System of Units (SI), approved by the General Conference on Weights and Measures (CGPM) in 2018, opened up a wider scope for the development and application of metrology. Starting from the definition of metrology, this paper analyzes the aspects and elements of metrology by deduction and induction and then puts forward the concept of "dimensions of metrology". The basics of metrology as a science, legal metrology, and application of metrology in industry are explored accordingly. It is proposed that the aspects of the basics of metrology include research on measurement theories, traceability of quantity values, new measurement devices, operational specifications, and analysis of measured values. It is proposed that the basics of metrology and legal metrology constitute a metrological infrastructure that underpins applications of metrology in various industries. Three development stages of metrology are reviewed from the perspective of the dimensions of metrology. The paper also looks ahead at new changes in the Era of Metrology 3.0 that may be brought about by the redefinition of SI.

The rapid development and application of radar technology provide more and more convenient means for acquisition of target information and bring great convenience to the life of residents. At the same time, with the rise of the demand for target information refinement the bandwidth and data volume of radar are also increasing, which limits further application of radar equipment to a certain extent. To solve this problem, 1-bit quantization technology has received more and more attention because of its advantage of reducing the amount of data. However, the highly nonlinear process of 1-bit quantization brings about frequency inter-modulation and greatly complicates signal components, bringing new challenges to radar detection. This paper analyzes this problem and theoretically shows the model of quantization noise. Then, it analyzes how the non-linear effect affects the performance of target detection in the radar system. This gives a good theoretical reference for design of radar system based on 1-bit quantization.

Based on the electrochemical-thermal coupling model, four 18650 Li-ion batteries were used as research objects to analyze the effect of convective heat transfer coefficient on the thermal diffusion of Li-ion batteries and its degree when considering the temperature effect. Firstly, the convective heat transfer coefficients on the surface of lithium-ion batteries at different temperatures and flow rates were calculated using the calculation method. Convective heat transfer coefficients as a function of temperature were obtained by curve fitting for air flow rates of 0.05, 0.1, 0.2 and 0.3m/s, respectively, and it was concluded that the convective heat transfer coefficient did not vary completely linearly with temperature. Secondly, based on the above functional relationship, the effect of convective heat transfer coefficient on the heat diffusion of lithium battery when considering temperature was analyzed by numerical simulation. The conclusion showed that the convective heat transfer coefficient when considering temperature had a different degree of influence on the temperature field of the battery. When the air-cooling flow rate was 0.05, 0.2 and 0.3m/s, respectively the temperature functions of the battery changed less than 1% during the discharging process. However, when the air flow rate was 0.1 m/s and the lithium battery was discharged to 729s the temperature field of the convective heat transfer coefficent considering the temperature factor decreased by 21.71% compared to the temperature field at the constant. This effect law was consistent with the variation of convective heat transfer coefficients with temperature at different flow rates. It also showed that the convective heat transfer coefficient was related to both flow rate and temperature. Moreover, the larger the convective heat transfer coefficient, the easier the lithium battery exchanged heat with outside air, and the smaller the temperature difference during the discharging of the battery.

The stratigraphic definition of the Carboniferous Yanghugou Formation in Ordos Basin is not clear and there are few studies on paleoclimate and paleoenvironment. To determine the age of the Yanghugou Formation, this paper studies the pollen fossils of the Yanghugou Formation in the Wuda section of the western Ordos Basin and restores the paleoclimate through the genetic relationship between pollen and paleovegetation. According to the species and content changes of palynofossils, two assemblages are established: Lycospora noctuina-Stenozonotriletes lycosporoides assemblage and Dictyotriletesbireticulatus-Ahrensisporites guerickei assemblage, which divide the Yanghugou Formation into lower and upper sections. By comparing with Yanghugou Formation in the Baiyantaohai area of Inner Mongolia and the Carboniferous-Early Permian fifth spore belts in the Zhongning-Zhongwei area of Ningxia, the ages of these two spore-pollen assemblages are determined, which are A-B stages and C-D stages of Westphalian, respectively, and equivalent to the Late Bashikian and the Moscovian in the International Age Strata.The spore fossil content of ferns in the lower segment of the Yanghugou Formation is slightly higher than that in the upper segment and the pollen fossil content of gymnosperms is slightly lower, but the overall change not significant, indicating a relatively stable climate of the Yanghugou Formation during the deposition period. The relationship between palynological fossils and ancient plant types is speculated. The ancient plants of the Yanghu Formation were mostly tropical-subtropical. Using the earth's chemical elements, this area should be a warm and humid tropical-subtropical climate.