全文总字数：21892字1. 研究目的与意义（文献综述） 1. Purpose and significance (including analysis of current research situation at home and abroad) Automobile suspension is the general name of all the connecting devices between the frame (or the bearing body) and the axle (or wheel). It is an important part to ensure the normal running of the vehicle. It consists of three parts: spring, shock absorber and guide mechanism [1]. The maximum total mass of medium-sized truck is 6.0t < GA ≤ 14 t according to the maximum total mass of (GA) set at the time of operation of highway. The main domestic manufacturers of light and medium-sized trucks are: Dongfeng, Chongqing Lifan, Zhejiang FeiDie, Chengdu Dayun, Heavy Automobile, Jianghuai, Qingling, Beiqi Futian and so on. At present, the suspension of domestic medium-sized trucks is mainly non-independent suspension. Suspension elastic elements are generally leaf springs. Because it acts as a guiding mechanism, the suspens

1. 研究目的与意义（文献综述包含参考文献）文 献 综 述 一、研究背景和意义 1.1研究背景 自改革开放以来，随着我国的不断发展，经济力量的不断雄厚，在交通建设的发展上也是一日千里。但是，尽管现在科技发达，交通的安全问题依然是个全球性的重大问题，交通安全隐患也一直是社会关注的重点问题之一。因此，直面并解决交通安全问题显得日益重要。 城市隧道作为城市交通的一个重要组成部分，在加快区域经济发展、改善行车条件、节约交通运输成本、减少事故发生、保护生态环境起着至关重要的作用。我国的隧道虽然起步比较晚，但发展极为迅速，因此也带来了相当严重的交通安全问题。 1.2研究意义 在我们的社会系统中，道路交通系统是极为复杂与危险的，这时，安全就显得非常重要，只有在道路安全上下足功夫，我们的社会经

全文总字数：20043字1. 研究目的与意义（文献综述） 1. purpose and significance (including analysis of research status at home and abroad) The increasingly stringent regulations on vehicle emissions and the reduction of fuel consumption through vehicle weight loss have become social requirements. to meet these requirements, automobile manufacturers must manufacture exhaust system components using materials with better corrosion and heat resistance. As a result, the materials for the components of the automobile exhaust system have begun to shift from traditional castings and aluminized steel plates to stainless steel[1]。 The United States began using ferrochrome titanium stainless steel for exhaust systems in the 1960s. Japan set standards for exhaust emissions in the 1970s, allowing automakers to add ternary catalytic devices to their exhaust systems to purify exhaust emissions. In the late 1980s, the Japanese government also stipulated the service life of the aut

1. 研究目的与意义（文献综述） 1.目的及意义 无轴轮缘推进器是一种先进的新型电力推进器，它采用螺旋桨—电机一体化设计思想，它具有解放机舱空间、高效节能和减振降噪等显著优点。该推进器采用完全水润滑轴承系统，包括水润滑径向轴承和水润滑推力轴承，其中水润滑推力轴承需要承担螺旋桨产生的推力，是无轴推进器的关键部件。[1] 水润滑轴承特点：随着水润滑轴承的推广，改变了长期以来机械传动系统中都是以金属构建组成摩擦副的传统观念，节省了大量的油料和有色金属。简化了轴系结构。避免了因油泄漏污染水环境的状况。由于水性质的特殊：粘度低，沸点低。因此在设计和选用水润滑轴承特点时，必须按照实际使用情况，进行详细研究分析，在尽可能消除或者避免水润滑介质这些缺点的情况下完成水润滑轴承的设计和选用。

全文总字数：18103字1. 研究目的与意义（文献综述） 1.1 Research Purpose: Suspension is one of the important assemblies on modern cars thatelastically connect the frame (or body) to the axle (or wheel). While its maintask is to transmit all the forces and moments acting between the wheel and theframe (or the body), it has multiple other purposes to serve such as; tomitigate the impact load transmitted by the road to the frame (or the body), toattenuate the vibration of the Chassis caused by the car, and to ensure thecar's smooth ride; to ensure that the wheel has ideal motion characteristicswhen the road is uneven and the load changes and to ensure the steeringstability of the car, so that the car can obtain high-speed driving ability[1]. In this research, a rear torsion beam suspension will be designed for DongFeng Peugeot 308 sedan using the given design parameters with the focus on; ·mastering theunderstanding of assembly and function of the suspension system ·des

1. 研究目的与意义21世纪以来，慢性肾脏病已成为危害全世界人民健康的公敌之一。据国际肾脏病协会统计慢性肾功能衰竭(CRF)在自然人群中的年发病率为98-198/100万，血液透析是肾功能衰竭患者肾脏替代治疗方式之一。由于肾脏病人群的不断增多，进行血液透析的人也随之增加，血液透析液的安全性有效性也具有了更重要的意义。在血液透析液中的主要成分为Na、K、Ca、Mg四种阳离子，Cl和碱基两种阴离子，探究出不同离子在人体内对人体的基本体征的作用，是保证血液透析液对不同患者血液透析后安全有效性的基本保障。而临床实验的有效安全的进行，要有一套良好的临床试验方案进行操作的规范与约束，只要当医疗器械在临床试验阶段得到了良好有效的测试，才可以进入市场。 所以通过临床试验研究观察改变血液透析液中成分含量及生产工艺等�

1. 研究目的与意义（文献综述） 1.1 Research Purpose: Suspension is one of the important assemblies on modern cars thatelastically connect the frame (or body) to the axle (or wheel). While its maintask is to transmit all the forces and moments acting between the wheel and theframe (or the body), it has multiple other purposes to serve such as; tomitigate the impact load transmitted by the road to the frame (or the body), toattenuate the vibration of the Chassis caused by the car, and to ensure thecar's smooth ride; to ensure that the wheel has ideal motion characteristicswhen the road is uneven and the load changes and to ensure the steeringstability of the car, so that the car can obtain high-speed driving ability[1]. In this research, a rear torsion beam suspension will be designed for DongFeng Peugeot 308 sedan using the given design parameters with the focus on; · mastering theunderstanding of assembly and function of the suspension system · designing and analyzing

1. 研究目的与意义（文献综述） 一、课题的目的与意义 随着国民经济的增强，我国高速公路建设发展迅速。与此同时，汽车运输也进入一个快速发展时期，交通量增大，重载车辆日益增加，对沥青路面带来严重的考验，从而对沥青和沥青混合料提出了相应的路用性能要求。目前，我国道路高等级路面主要是沥青混凝土路面，要使路面具有足够承载力和良好的耐久性，除了要有稳定的路基外，主要取决于路面结构和路面结构层的配合比。高等级路面结构已基本成定局：20cm 厚的石灰土，18－19cm 厚二灰碎石，18cm 厚水泥碎石，15cm 厚沥青混合料。15cm 厚沥青混合料分三层铺筑，6cm 粗粒式沥青混凝土，5cm 中粒式沥青混合料，4cm 中粒式沥青混合料[4]。因材料、施工设备和施工工艺的限制，路面结构基本定型。所以，要改变路面使用性能，提高路面服务水�

1. 研究目的与意义（文献综述） Research purpose: According to EnglishCurriculum Standards for Compulsory Education (2017), natural and normativepronunciation and intonation will lay a good foundation for effective communication.Yet it is noticeable that compared with the counterparts in urban areas, thecurrent middle school students in rural areas have more problems anddifficulties in English pronunciation due to the shortage of high-qualityteachers, the backward teaching methods, the restricted language learningenvironment and the lack of parents’ supervision. Although there is someresearch about oral English for middle school students, the study mainly aimsto explore oral English learning problems and teaching strategies based on oralcommunicative competence and teaching methodology, principally focusing onteachers rather than students. This research will shift the focus to studentsand explore English pronunciation problems of middle school students in ruralChina base

全文总字数：12321字1. 研究目的与意义（文献综述） As the environmental protection and low-carbon electric vehicle has been more popular in the current social environment, and the research of electric drive vehicle is the inevitable trend of the development of electric vehicle industry in the future. With the rapid develop-ment of modern automobile technology, people will also have new requirements for the driving safety, maneuverability, smoothness and economy of the vehicle. With the progress of science and technology, the mature technology of the traditional automobile can not fully support the new development. As a rather complex system, the dynamic structure of the automobile also needs further research, which can improve the safety and stability of the vehicle chassis dynamics control system from three aspects: longitudinal dynamics control, lateral dynamics control and integrated dynamics control[3]. The main research object of this paper is distri