Vigorously developing transportation is an important guarantee to accelerate the realization of China’s modernization. Modern transportation in all directions plays an important role in strengthening the unity of the people of all ethnic groups, developing the national economy, promoting cultural exchanges and consolidating national defense. In the construction of highway, railway, urban and rural road traffic and water conservancy, in order to cross various obstacles (such as rivers, valleys or other lines), various types of bridges or culverts must be built, so bridges and culverts have become an important part of land transportation. Especially in the construction of modern high-grade highway and urban viaduct, road and bridge are not only very large in scale, but also the key to ensure the whole line to be opened to traffic as soon as possible. In national defense construction, bridges are the throat of transportation. It plays a very important role in the modern war which needs high speed and mobility.
With the progress of science and technology, the improvement of industrial level and the rapid development of social productivity, people put forward higher requirements for road and bridge construction. The overpasses, viaducts and urban viaducts moving back and forth on modern expressways, Gulf and Strait bridges with tens of meters, suburban high-speed railway bridges and light rail transportation viaducts are not only large-scale engineering entities, but also like a rainbow on the ground, which make the city look particularly beautiful.
Throughout the world’s major cities, often with the majestic bridge as the symbol and pride of the city. With the continuous expansion of road and bridge construction scale, the role of large bridges in national economy and social life is becoming more and more important.
大力发展交通运输事业是加速实现我国现代化的重要保证。四通八达的现代交通,对于加强全国各族人民的团结， 发展国民经济,促进文化交流和巩固国防等都具有非常重要的作用。在公路、铁路、城市和农村道路交通及水利等建设中,为了跨越各种障碍(如河流,沟谷或其他线路等)，必须修建各种类型的桥梁或涵洞,故桥涵已成为陆路交通的重要组成部分。 特别是在现代高等级公路及城市高架道路的修建中,道路桥梁不仅在工程规模上十分巨大,还往往是保证全线早日通车的关键。 在国防建设上,桥梁是交通运输的咽喉。 在需要高度快速、 机动的现代战争中具有非常重要的地位。
随着科学技术的进步， 工业水平的提高,社会生产力的高速发展,人们对道路桥梁建筑提出了更高的要求。现代高速公路上迁回交叉的立交桥、高架桥和城市高架道路， 数十米的海湾和海峡大桥,新发展的城郊高速铁路桥与轻轨运输高架桥等不但是规模巨大的工程实体，而且犹如一条地上彩虹，将城市装扮得格外美丽。
In recent years, the application of ultrasound in medicine has been developing rapidly. Ultrasound diagnosis, with its simple, injury-free, pain-free, high accuracy and good repeatability, has been generally welcomed by clinicians and patients, and has become one of the most commonly used methods to diagnose diseases. With the development of ultrasound technology and ultrasonic instruments, ultrasound medicine has become more and more widely used, and has gradually become an important content that ultrasound medical workers must learn.
Ultrasound medicine is a diagnostic method of ultrasound comprehensive imaging, which is a highly theoretical and practical subject, and is widely used in clinical medicine. It not only involves general internal surgery, obstetrics and gynecology, pediatrics and other major departments, but also has close contact with many specialties such as neurology, cardiovascular, urology, endocrinology, oncology, etc. With the increasing scope of clinical application of ultrasound imaging technology, in order to facilitate medical personnel to learn and use ultrasound diagnosis and treatment technology, we compiled this book on the basis of a large number of domestic and foreign literature.
The Editorial Board Members of this book has grasped the principle of “less and more refined” and simplified as far as possible. Due to the limitation of space and the level of the editor, there are inevitably some omissions and improperieties in the content of this book, readers are welcome to criticize or correct them.
China’s economic and social is continuously developing, and the construction industry has entered a stage of rapid development. In the development process of the construction industry, project management occupies an important position. Only by improving the efficiency and level of project management, can we ensure the quality of construction projects and promote the healthy development of the construction industry. As an important branch of management science, construction project management has its own characteristics. Construction engineering project management is known as an important aspect of project management in the 21st century. Construction engineering companies face a more complex competitive environment and stronger competitors. In order to compete for market and survival space, enterprises should stand at the height of strategy and cultivate long-term competitive advantages. Cost management is a new tool to enhance the competitiveness of enterprises.
In recent years, with the acceleration of the urbanization, China’s construction industry has shown a rapid development trend, and the scale of construction projects has been expanded to a certain extent, which has put forward new requirements for construction engineering management. Based on this, the management personnel should combine the current construction engineering management needs of our country, try to apply project management to the construction engineering management work, gradually improve the management efficiency and management standardization, provide corresponding guarantee for the strengthening of construction engineering management quality, and provide certain support for the modernization construction and development of the industry. Based on many years of experience in construction engineering management, this book systematically summarizes the management knowledge of construction engineering for reference of construction management workers.
Highway bridge engineering detection is an important part of highway bridge construction quality management. Through the test and detection, the quality of various raw materials, semi-finished products and finished components can be evaluated quantitatively, so as to make full use of local raw materials, and rapidly promote the application of new materials, new technologies and new processes, and reasonably control the construction quality and scientifically evaluate the quality of highway and bridge engineering. Therefore, the test and detection work will play a very important role in ensuring and improving the project quality, speeding up the construction progress, reducing the project cost and promoting the progress of highway engineering construction technology.
The detection technology of highway and bridge engineering is a new developing subject, which integrates the theoretical knowledge of test, detection, practical operation skills and related basic knowledge, involves a wide range of knowledge, and contains more project contents. In order to enable the engineering, testing personnel or quality control management personnel to acquire relatively systematic and complete highway bridge construction detection knowledge, so as to do a good job in the key links of engineering material quality, construction control parameters, on-site construction process quality and engineering quality acceptance, this book is specially compiled.
Due to the rapid development of new methods, new technologies and new specifications of highway engineering test and detection, as well as the limited level of the editor, there are inevitably some defects in the book. The majority of teachers and students and readers who use the book are welcome to criticize and correct them.
由于公路工程试验检测新方法、 新技术及新规范发展迅速， 加之编者水平有限，书中难免存在不妥之处，敬请使用本书的广大师生和读者批评指正。
With the rapid development of China’s construction, in order to strengthen the construction management of mechanical and electrical engineering, ensure the engineering quality and construction safety, it is imperative to improve the quality of mechanical and electrical engineering professional and technical personnel, and standardize the construction management behavior. With the advent of the electronic age, the traditional manual industry is gradually replaced, and electromechanical equipment is widely used in highway engineering. Therefore, the number of mechanical and electrical equipment installation is increasing rapidly, which inevitably leads to some problems in the installation process. These problems seriously affect the quality and safety performance of mechanical and electrical equipment, so we should understand the installation process and precautions of mechanical and electrical equipment, and clarify the structure and installation sequence of mechanical and electrical equipment. The level of mechanical and electrical engineering construction technology determines the construction progress, quality, safety and economy of the project, directly affects the benefit of the construction enterprise, and determines the sustainable development ability and competitiveness of the enterprise. The construction technology level of the enterprise is composed of the basic quality and technical level of several project leaders, constructors and all construction personnel.
This paper mainly describes the construction of mechanical and electrical installation of common quality problems and its prevention and control measures. In the mechanical and electrical installation construction work, including a variety of engineering projects, including drainage engineering, weak current engineering and electrical engineering, as well as fire engineering and air conditioning and ventilation engineering. The important part of mechanical and electrical installation engineering is electrical engineering and weak current engineering. Therefore, the material quality should be controlled, the installation technology level should be improved, and the construction management should be strengthened. Due to the lack of experience of the editor, there may be mistakes and omissions in the article. Readers are welcome give criticism and correction.