Michael addition reaction refers to the conjugate addition reaction of carbocation to α, β-unsaturated aldehydes, ketones, carboxylic acids, esters, nitrile, nitro compounds, etc. The reaction is an essential organic reaction, and it is used in organic synthesis to grow carbon chains and synthesize organic compounds with various functional groups. As one of the most valuable organic synthesis reactions, it is one of the most common ways to construct carbon-carbon bonds. This paper analyzes the mechanisms and the theories of some common Michael addition reactions. It also includes an example of the research of Michael addition in recent years. In a recent study, a research team experimentally found a suitable catalyst to catalyze the Michael addition reaction on benzyl groups, and obtained the different performances of benzyl groups with different functional groups during addition. Cyclopentadienyl rhodium catalyst has excellent catalytic activity and selectivity for benzyl first, second, and third C/H bonds. The reaction can be compatible with halogen, ester, and amide functional groups.

The wide usage of microplastics and heavy metals has led to the accumulation of these pollutants in our environment. Among heavy metals and microplastics, Cadmium (Cd), polyvinyl chloride (PVC), and polyethylene (PE) are the most severe and ubiquitous pollutants. With large surface areas, microplastics have the ability to absorb metal ions, potentially performing "carrier effect", by which microparticles enhance the transfer of other pollutants from soil to plants. Phytoextraction has been shown to be the most effective strategy to remediate heavy metal contamination. In this study, we selected Galinsoga quadriradiata (G. quadriradiata) as the test species to investigate the effectiveness of phytoextraction in soil contaminated with Cd, PVC and PE. According to our results, G. quadriradiata present effective phytoextraction to Cd and microplastics. However, the carrier effect between Cd and PVC or PE only exists in the value of maximal quantum efficiency of photosystem II (Fv/Fm) but has no effect on the uptake of Cd by G. quadriradiata. For future studies, we propose to investigate the carrier effect between heavy metals and microplastics in plants, test the pathway of microplastics by which they are up-taken by plants from soil, and increase the efficiency of phytoextraction by exposing plants (such as G. quadriradiata) that have been proved to absorb heavy metal to microplastics.

The seismic vulnerability analysis is of great important for the design, operation and maintain. The selected extra-large highway and railway dual-used arch bridge contains high geometric nonlinearity and is one of the transportation junctions. Therefore, it is necessary to conduct seismic response analysis. The research results can provide reference for the seismic design and seismic response analysis of target bridge and similar typed bridges. Thus, it has high theoretical value for the design and promotion of similar bridges. This paper starts with a theoretical analysis, using the finite element software LS-DYNA to build a dynamic calculation model of the real bridge and carry out modal and time response analyses. The strength, vulnerable components and stability of the bridge under three-way seismic action at for different earthquake excitation waves (Wenchuan earthquake, Chichi earthquake, Kobe earthquake and El-Centro earthquake) are investigated. Through analysis and comparison of numerical calculations, the seismic performance of the target bridge was comprehensively evaluated.

With the rapid development of building level and construction technology, high-rise buildings have been adopted more and more, thus becoming an important place for people to work and live. Because of the high height of high-rise buildings, wind load becomes the main resultant force type of high-rise building. However, wind load has great randomness and unpredictability, which has great influence on the stability of high-rise building. This paper first analyses the main characteristics of wind load borne by tall buildings. Then, the common methods of wind-resistant design of high-rise building are summarized in detail. It also points out the existing problems and deficiencies in wind resistance design of high-rise buildings and the countermeasures and suggestions of wind resistance design of high-rise structures. Finally, according to the current research status and existing problems, the future development of wind resistance design is prospected. Results can provide some references for wind resistance design and research of high-rise buildings.

With the development of modern engineering technology, more attention is paid to the aid of digitization and information in the process of engineering project design and construction. Building Information Model (BIM) realizes the transformation from traditional building project to modern building project. At the same time, it also greatly promotes the digital development of construction projects. BIM technology as a modern information technology in the application of construction engineering, has a variety of benefits. For example, it can improve the quality of projects. In addition, the application of BIM technology in the whole process of construction projects can reduce costs and improve efficiency. However, there are many risks associated with using BIM in construction projects. This paper analyzes the advantages of BIM technology in visualization and coordination, and the application of BIM in design, construction, management and other aspects. Then, the risks and countermeasures in BIM application are discussed. The research results are of great significance to improve the informatization level of construction projects.

Building construction involves many complex processes such as high-altitude operations, mechanized equipment operations, and transportation and handling of building materials. Construction is a high-risk industry with frequent accidents. Therefore, some efficient and practical preventive measures need to be proposed immediately to reduce the occurrence of these accidents. This paper introduces different types of construction accidents and analyzes the reasons in combination with the theory of accident causation, to provide implementable ways to improve the safety performance of construction projects. Finally, a few precautions are offered in this paper to prevent the similar accidents from happening. The research results show that measures such as improving the safety evaluation system, strengthening the operating environment, strictly controlling the installation and dismantling links, enhancing the lighting conditions at night, and controlling minor accidents can effectively prevent the occurrence of construction safety accidents.

As the population and urbanization have continued to grow all over the world, the construction industry demands more efficient, and greener ways of building. In recent years, prefabricated buildings have attracted widespread attention as a new construction method. BIM technology is a crucial element in the realm of digital architectural design and construction. Its implementation can effectively enhance the support and optimization of the prefabricated building's design and construction process. This paper aims to explore the application of BIM technology in the design and construction stages of prefabricated buildings. Firstly, the utilization of BIM technology in prefabricated building design is expounded from three aspects of digital model construction, architectural collaborative design and architectural design optimization. Then, the implementation of BIM technology in prefabricated building construction is analyzed with regard to three aspects: development of construction plans, on-site management, and quality control. Subsequently, the application of BIM technology in the design of high-rise prefabricated buildings and the construction of prefabricated buildings is introduced in detail through case studies. The results show that the application of BIM technology can improve the design efficiency and construction quality of prefabricated buildings, and has a good application prospect.

Building Information model (BIM) is a kind of digital building information model. Through BIM technology, building information can be presented to each department of building engineering in the form of three dimensional (3D). In traditional building information management, design part and construction part are independent of each other. There is no unified standard and information management system between the two sides. As a result, the construction information between the design department and the construction department cannot be shared in time, and both sides are prone to make mistakes in the negotiation of construction issues. These mistakes not only delay the construction, but also increase the construction cost. With the development of BIM technology, each department of building can understand the details of the building more intuitively through the building information model. Designers and builders can communicate effectively in construction projects and coordinate problems in the construction process.

Nowadays civil engineering is facing the transformation of the combination of intelligent, digital and other modern new technologies. Civil engineering, as a traditional industry, may not be able to meet the efficiency and requirements of today's technological society. In order to adapt to the development of society, civil engineering is trying to transform to other disciplines. In recent decades, intellectualization and digitization have begun to affect the way civil engineering works and operates. In fact, intellectualization and digitalization can affect every stage of the whole civil engineering process, including the design stage, construction stage and service stage. The purpose of this paper is to discuss the application of intelligence and digitization in civil engineering. Some of the most important applications are listed and further explained, and the future development prospect is preliminarily analyzed and prospected. By enumerating the innovation brought by intelligence and digitalization to civil engineering, it inspires people to carry on more in-depth thinking, further adaptation and new adjustment to the future civil engineering.

With the continuous progress of China's urbanization, problems such as rainwater runoff pollution, flood disaster and water resource shortage have become increasingly prominent. Sponge city is a good way to solve urban waterlogging and improve the water ecological environment. This paper first describes the water resources issues encountered by Chinese cities, and then it explains the significance of sponge city building, in order to further apply the idea of water ecological civilization construction and promote the construction of sponge city. China's creation of sponge cities is still in its early stages when compared to Western nations. In this paper, the effectiveness of the construction of Jiaozuo sponge city is examined together with the research state of sponge city construction in China. Finally, this paper discusses some problems in the process of sponge city construction and puts forward some concrete suggestions. It is expected to play a reference role in promoting the development of sponge city and improving the construction of sponge city in China.

With the rapid development of railway engineering, the scope of railway construction has been extended to mountainous areas, basins and other geological environments. In these areas, railway construction needs to pay attention to landslides, earthquakes and other disasters, otherwise it will threaten unnecessary economic losses and even personal safety. The purpose of this paper is to introduce the disaster threats faced by railways and the measures to prevent these disasters, especially earthquakes and landslides, and to look at the future development trend of prevention and control. Earthquake early warning is one of the effective means to improve the safety of high-speed railway. As for the railway crossing the high earthquake wind area, it can be considered to establish the earthquake early warning and monitoring system for effective protection. For landslide disaster, interference should be reduced in the construction process, and special evaluation and targeted engineering treatment.

With the popularity of building construction worldwide, building design, construction technology and quality are faced with inherent deficiencies and may be hit by disasters. Therefore, the diagnosis and reinforcement of building structure has become a major problem to be solved urgently in the current building construction. This paper introduces simple detection methods of different building structures and reinforcement techniques under different conditions. In the part of detection methods, various basic detection methods of normal building structure are studied. Then, a special damage appearance is discussed. Besides the traditional electronic imaging method to detect cracks, a special method is proposed to solve the crack problem, namely Min-Max Gray Level Discrimination (M2GLD). This method can improve the detection accuracy and reduce the influence of human factors. At the same time, several different reinforcement techniques are proposed, including traditional reinforcement techniques and advanced reinforcement techniques. This paper introduces the traditional technology of ancient timber structures and the technology of spraying and external bonding FRP to enhance flexural, shear and compressive strength. This paper can be used as reference for structural inspection and reinforcement of existing buildings.

Project cost control is a hot issue in construction enterprise management and a key factor to determine the return on project investment. With the continuous summary of modern project management experience, systematic, comprehensive and dynamic management methods and ideas gradually began to be adopted. As a controllable system, cost system is the key to determine the market competitiveness of construction enterprises. This paper combines qualitative research with quantitative research, normative research with empirical research, theoretical research with practical research, and makes comprehensive use of previous research results to provide guidance for the practical operation of cost control in construction enterprises. Firstly, it introduces the important factors affecting the cost and the background and purpose of the project cost control, and then analyzes the object and content of the project cost control and analysis. Finally, the phenomenon of "three super" and the deviation of the project cost are analyzedd and discussed. It is of great practical significance to study project cost control for promoting the reform of investment system and improving market competitiveness of construction enterprises.

Changes in the prevention and control situation in the post-epidemic era have spawned a more complex campus living environment, and new space requirements have gradually formed considering interpersonal relationships and distance. The campus is a space worthy of attention and transformation as it is a densely populated space. Taking Bingwen Academy of Southeast University in China as an example, this paper describes a specific space transformation project, evaluates its main advantages and problems, and proposes some suggestions with an analytic hierarchy process. There are five assessment criteria in the space transformation: functional layout, design and materials, horticultural planting, furnishings and detail decoration, and intelligent security and management. Results show that the reformed space is a multi-functional and "living-study" physical environment. It has different usage scenarios with flexible and changeable spatial layouts and provides various activities for teachers and students with the concept of living and learning integration, co-construction, and sharing. It also promotes traditional culture and history spread through furnishings and details and educates people about morality. The reformed Bingwen Academy still has problems, such as inconvenient furniture moving, limited opening hours for all spaces, and lack of activity displacement. It is proposed to add modular furniture with rollers, manage different spaces by time, and add an achievement exhibition wall. This project provides a reference value for the space transformation of other college dormitories during and after the epidemic.

With the continuous growth of highway quantity in China, the post-maintenance of highways has become a focus of highway management, attracting widespread attention in the industry. Selecting an appropriate maintenance timing is of significant importance for highway maintenance. Based on the TOPSIS theory and the deterioration law of asphalt pavement performance indicators, this study takes cost, effectiveness, energy consumption, and carbon emissions as research indicators. Combined with the entropy weighting method and the analytic hierarchy process, the study establishes a decision model for determining the optimal preventive maintenance timing for asphalt pavement. This model determines the best timing for preventive maintenance of asphalt pavement through the values of relative closeness. Finally, by analyzing a practical maintenance case of a highway in Jiangsu Province, it is found that when the Pavement Condition Index (PCI) equals 90, it is the optimal timing for preventive maintenance of asphalt pavement, which verifies the rationality of the decision model and provides a scientific reference for selecting maintenance timing.

At present, the solar cells that occupy most market are still silicon solar cells. However, the power conversion efficiencies (PCEs) of the devices made of silicon have achieved an extreme value. Therefore, a new type of solar cells to get higher power conversion efficiencies are in great need. Since the 21st century, perovskite/silicon tandem solar cells have gained great attention because of their potential to offer higher PCE compared with other traditional solar cells. This article elaborates the inevitability of the development of perovskite/silicon crystal tandem solar cells from the perspectives of development history, cell structure. This article also discusses the different materials of both perovskite top cell layers and silicon crystal bottom cell layers in this new type of solar cell, including methylammonium lead iodide, formamidinium lead iodide, cesium lead iodide, crystalline silicon, thin-film silicon and heterojunction with intrinsic thin layer. This article mainly presents the characteristics and advantages and disadvantages of different materials when they are used in this new type device.

Perovskite/silicon tandem solar cells offer great potential for achieving high-efficiency solar energy conversion. Through the absorption of a wide range of wavelength sunlight, they are not limited by the Shockley-Queisser limit in single-junction silicon solar cells. They have shown impressive progress in recent years, reached a power conversion efficiency (PCE) of 32.5%, and have a bright prospect in the future. In light of the condition of the solar industry today, this article mainly introduces the development status and the main progress direction of the perovskite/silicon tandem solar cells in recent years. In terms of efficiency improvement, it primarily uses perovskite unit band gap tuning and recombination layer optimization. Then the typical cell structures (2-terminal and 4-terminal) and some innovations (3-terminal) are introduced. The summary of these frontier researches is valuable and can guide the direction for later improvement. Lastly, the perovskite/silicon tandem solar cells still have many opportunities and challenges and are expected to become more mainstream solar cells.

With the rapid development of integrated circuit (IC) technology, the size of devices has been continuously shrinking. While this trend has led to increased integration density, improved device reliability, and reduced costs, it has also resulted in performance degradation of metal-oxide-semiconductor field-effect transistors (MOSFETs) due to the short channel effect (SCE). This paper provides a comprehensive review of the most recent techniques that can mitigate the short channel effect in MOSFETs, with a focus on semiconductor materials and device structures. These techniques include decades-long advancements in doping and high-κ dielectric materials, as well as emerging structures such as Fin field-effect transistors (FinFETs), Gate-all-around field-effect transistors (GAAFETs), Forksheet field-effect transistors, and complementary field-effect transistors (CFETs). This paper can greatly assist researchers in establishing a theoretical foundation, identifying research problems and voids, and identifying hot spots and trends in short channel effect research through a comprehensive analysis of the existing research literature.

The expanding world population, increasing energy demand, and looming climate change urge the development of a sustainable energy future while safeguarding our vulnerable environment. To build a new flexible battery system, high entropy oxides are used as electrodes based on zinc-ion batteries. The battery system with the best electrochemical performance can be determined by a series of experimental designs. Here in I propose to develop a HEO electrode using a fast and clean laser deposition method. A series of tests are designed to verify the degree of performance improvement. In the further research planning, the electrode material can be produced with a metal removed from the HEOs alone and using the same synthetic method and performance measurements to determine the roles of each metal in the HEOs. Additionally, the anions in the HEOs can also be varied to study the impact of various anions on the cell's electrochemical performance. Finally, the particle size of the HEOs can be varied to establish a correspondence between particle size and electrochemical performance to facilitate the selection of the optimum particle sizes. The experimental results can further provide a theoretical basis for the commercial application of zinc-ion batteries in flexible power systems.

Earthquake is a devastating natural disaster that can easily cause buildings to collapse, posing a serious threat to human life. Concrete, as a widely used building material, is of significant concern for its seismic performance. This paper mainly presents how seismic resistance can be considered in concrete building design and proposes two main solutions, the use of high-performance materials and rational structural placement. Through comparison and analysis, it finds that rationalization of the structural placement is the preferred and feasible solution for the future between the two. The successful development of computer software has dramatically reduced the workload of structural modeling and analysis. At the same time, the combination of considering the use of high-performance materials and rationalizing the structural placement is a highly effective approach, which requires more time from the researcher to solve the difficulties and challenges. This paper provides a clear direction for research into seismic problems in concrete buildings.