In the 21st century, material science is developing vigorously; new materials and new technologies emerge endlessly, which greatly promote the development of science and technology and national economy. It is very important for engineering students to have a proper understanding of the direction of modern materials development.
  Machinery is manufactured. Due to the different types of machinery and equipment in all walks of life, mechanical manufacturing involves a wide range of areas. Metallurgy, construction, water conservancy, machinery, electronics, information, transportation, agriculture and other industries need the support of manufacturing industry. Metallurgy industry needs smelting and rolling equipment; construction industry needs tower crane, excavator, bulldozer and other engineering machinery. Manufacturing industry has always occupied an important position in China. In the 1950s, the machinery industry was divided into eight sectors: general, nuclear, aviation, electronics, ordnance, shipbuilding, aerospace and agriculture. In the 21st century, the world is undergoing extremely extensive and profound changes, and the machinery manufacturing industry affected by it has also undergone earthshaking changes. However, no matter how the world changes, machinery manufacturing industry has always been the basic industry of the national economy, and its development directly affects the development of all sectors of the national economy.
  In the compilation of this book, we have consulted a large number of domestic and foreign teaching materials, treatises and other literature materials. Due to the limited space, they will not be listed one by one. Sincere thanks would be expressed to the authors of these literature. At the same time, due to the editor's limited level and ability, there are inevitable mistakes and omissions in the book. We sincerely hope that experts, scholars and readers can criticize and correct them, so as to further improve them in the future. 

前 言

进入 21 世纪，材料科学蓬勃发展，新材料、新技术层出不穷，极大地推动了科学技术和国民经济的发展。适当地了解现代材料的发展方向对于工科学生具有极其重要的意义。
       机械是制造出来的，由于各行各业的机械设备不同、种类繁多，因此机械制造
的涉及面非常广，冶金、建筑、水利、机械、电子、信息、运载和农业等各个行业都要有制造业的支持，冶金行业需要冶炼、轧制设备；建筑行业需要塔吊、挖掘机和推土机等工程机械。制造业在我国一直占据重要地位，在 20 世纪 50 年代，机械工业就分为通用、核能、航空、电子、兵器、船舶、航天和农业等八个部门。进入21 世纪，世界正在发生极其广泛和深刻的变化，随之牵动的机械制造业也发生了翻天覆地的变化。但是，不管世界如何变化，机械制造业一直是国民经济的基础产业，它的发展直接影响到国民经济各部门的发展。
      在本书的编写过程中，我们参阅了大量国内外教材和论著等文献资料，由于篇幅有限，恕不一一列出，在此对这些文献的作者一并表示诚挚的谢意。同时，由于编者水平和能力有限，书中难免存在错误与遗漏，我们诚恳地希望各位专家、学者和广大读者批评指正，以便今后进一步完善。

n recent years, the development of machinery manufacturing industry in China has been stable, and it has become one of the important pillar industries in China. However, there is still a certain gap between China’s machinery manufacturing technology and foreign manufacturing technology, which leads to the disadvantage of China’s manufacturing technology in the international competition. Therefore, to optimize the design of mechanical manufacturing process, the first consideration is the error control of manufacturing process; Secondly, we must fully implement the requirements of mechanical design and manufacturing, produce and manufacture in strict accordance with the design plan, and gradually improve the level of mechanical design on the basis of ensuring the rationality of mechanical manufacturing process. It is an important trend to improve the overall level of mechanical manufacturing by optimizing the design strategy to adapt to the growing material demand. At present, with the continuous improvement of national science and technology, the mechanical manufacturing process is also progressing. In mechanical manufacturing, mechanical design plays a very important role, which directly affects the performance and quality of finished products. Therefore, in mechanical design, rational design is very important, which has high technical requirements for materials and production specifications. This book discusses the needs of mechanical manufacturing process, takes mechanical rationalization as the goal, and optimizes the mechanical design appropriately, so as to effectively improve the rationality of mechanical manufacturing process.

前 言

近年来，机械制造产业在我国的发展一直保持平稳态势，同时也成为我国的重要支柱产业之一。然而我国机械制造工艺相较于国外制造技术还存在一定的差距，导致我国的制造工艺在国际竞争中处于劣势地位。为此，要对机械制造工艺进行优化设计，首先要考虑的就是制造过程的误差控制，其次必须全面落实机械设计和制造的工作要求，严格按照设计计划生产制造，同时要在保证机械制造工艺合理性的基础上，逐渐提升机械设计水平。而通过优化设计策略来提升机械制造整体水平，以适应不断增长的物质需求是当前发展的重要趋势。当前，国家的科学技术水平不断提高，使得机械制造工艺也不断进步，在机械制造中，机械设计发挥着非常重要的作用，直接影响到成品的性能和质量，所以在机械设计中，合理化设计是非常重
要的，其对材料与生产规范都有较高的技术要求，本书通过对机械制造工艺的需要做讨论，以机械合理化为目标，对机械的设计进行适当的优化，从而有效地提升机械制造工艺的合理程度。

Therapeutics of neurological diseases is a jewel in the crown of medicine. It attracts a  group of outstanding doctors to go deep into this profession and explore hard for it with its  fine neuroanatomy, strict thinking logic, unique treatment methods, and remarkable  clinical effects. Despite rapid advances in science and technology, there are still no  satisfactory treatments for many difficult and critical neurological diseases, and a large  number of patients are still in a state of isolation and helplessness.            

Nervous system diseases are difficult to diagnose and treat. They are currently  recognized as intractable diseases in the world. Except for a few diseases such as nervous  system infections and individual cerebrovascular diseases that can be completely cured,  other diseases still lack effective means, which seriously threaten people’s health and bring  heavy burden to the family and society. Although modern medicine has made great  progress, nervous system diseases have not yet got rid of the embarrassing situation of  “three elements” (antibiotics, vitamins and glucocorticoids). For thousands of years,  Chinese medicine has accumulated rich experience in the treatment of nervous system  diseases, and has certain advantages. However, in the process of sorting out, we found that  many diseases were not fully understood in ancient times, and there was no corresponding  disease name. We could not directly refer to the experience of the ancients. We only need  to study and obtain relevant experience in the actual treatment process.

前 言  

神经系统疾病治疗学是医学皇冠上的一颗明珠，它以精细的神经解剖、严密的 思维逻辑、独特的治疗方法、显著的临床疗效而吸引着一批又一批优秀的医生深入 到这个专业，为之辛勤探索。虽然科学技术的进步迅速，但许多神经病学的疑难、 危重疾病仍然没有满意的治疗方法，大量患者仍处于孤立无援的状态。 

     神经系统疾病诊断疑难、治疗困难，是目前世界上公认的难治性疾病，除神经系统感染、个别脑血管病等少数疾病可以完全治愈之外，其他疾病尚缺乏有效的手段，严重威胁人民群众健康，给家庭和社会带来沉重的负担。虽然现代医学已有了长足发展，但神经系统疾病仍未摆脱“三素”（三素即抗生素、维生素和糖皮质激 素）的尴尬境地。千百年来，中医药在治疗神经系统疾病方面积累了丰富的经验，具有一定的优势。但是，我们在整理的过程中，发现很多疾病在古代没有充分的认识，也没有相对应的病名，无法直接参考古人的经验，只能需要我们在实际治疗过 程中研究并获取相关经验。

With the development of China’s economy and the continuous improvement of people’s material living standards, as a vertical means of transportation, elevator has been integrated into all aspects of our life. However, in recent years, due to the inconsistency of elevator safety specifications and standards, people generally pay attention to elevator installation, despise maintenance and other factors, resulting in continuous elevator accidents. In addition, due to the rapid development of the elevator industry, there is a shortage of elevator manufacturing, marketing, installation and maintenance practitioners in China. In addition, the elevator management, inspection and R & D professionals and the public groups who use elevators urgently need to understand the elevator as a special equipment.
  After nearly 30 years of development, China’s elevator industry has developed from the annual output of more than 2000 sets and the ownership of 10000 sets in the early 1980s to the production and sales of more than 400000 sets and the ownership of more than 2 million sets in 2011. China’s elevator production has exceeded 60% of the global production. In recent years, with the rapid growth of high-rise residential buildings, elevator has become a means of transportation for ordinary people to travel, and the safety of elevator has also become a livelihood problem. At the same time, because of the introduction of many foreign elevator products (including Sino foreign joint venture elevator products), these products are more advanced in the world. However, the current elevator technology in China is relatively backward, which is not normal. Therefore, the research on mechanical engineering and elevator construction technology is of great significance.

前 言

随着我国经济的发展，人民物质生活水平不断提高，作为建筑物的垂直交通工具—电梯已融入我们生活的方方面面。但近年来由于电梯安全规范和标准不统一，普遍注重电梯安装、轻视维修保养等因素造成电梯事故不断。另外，由于电梯行业的快速发展也使我国电梯制造、营销、安装和维修保养的从业人员紧俏，加上电梯管理、检验和研发的专业人员和搭乘使用电梯的大众群体迫切需要深入地了解电梯这个特种设备。
       我国电梯行业经过近 30 年的发展， 已经从 20 世纪 80 年代初二千多台的年产量和 1 万台的保有量， 发展到 2011 年 40 余万台产销量， 以及超过 200 万台的保有量，我国的电梯产量已经超过了全球产量的 60%。近几年高层住宅的快速增长，电梯已成为寻常百姓出行所依赖的交通工具，电梯的安全问题也成为了民生问题。与此同时。由于我国引入很多国外的电梯产品(包括中外合资的电梯产品)，这些产品在国际上都是比较先进的，而我国目前的电梯技术与此相比相对落后，这是不正常的。因此，对机械工程与电梯施工技术研究具有重要意义。

This book starts with the status of chemical industry in the national economy, the characteristics and risk analysis of chemical production, and the prevention and control theory of chemical machinery and equipment maintenance and safety. For the chemical equipment itself, it must meet the special conditions such as high temperature, high pressure, high vacuum, ultra-low pressure, inflammable, explosive and strong corrosivity often encountered in the chemical production process, as well as the requirements of modern chemical production scale. This requires daily training and education for managers and operators in the chemical industry in the use process and precautions of work, as well as the maintenance and maintenance technology of daily safety fire equipment.

前 言

本书从化学工业在国民经济中的地位、化工生产的特点及危险性分析、化工机械设备维护及安全的预防及控制理论入手，对于化工设备本身而言，必须满足在化工生产过程中经常会遇到的高温、高压、高真空、超低压、易燃、易爆以及强腐蚀性等特殊条件，以及现代化工生产规模要求。这就更需要在工作的使用流程及注意事项，以及日常安全消防器材的维护保养和维护技术过程中，进行化工行业管理人员和操作人员的日常培训和教育。