全文总字数：9690字1. 研究目的与意义（文献综述） 1Purpose and significance 1.1 Research Background For information on trucks using a combination of internal combustion engines and electric propulsion, see Hybrid electric truck.Electric Renault Midlum used by Nestlé in 2015.An electric truck is an electric vehicle powered by batteries designed to deliver cargo.Electric trucks have been around in niche application areas for over a hundred years, but more recently the advent of lithium ion batteries has enabled the range of electric trucks to increase to several hundred miles, making them of much wider applicability.Electric trucks are becoming an alternative to traditional trucks, while creating no local pollution. Due to the high efficiency of electric power trains, running costs are expected to be lower.Their simplicity is also supposed to make maintenance costs much lower.However, electric trucks are usually heavier than diesel trucks, the energy density of lithiu

1. 研究目的与意义随着21世纪的到来，互联网走进千家万户。计算机业的飞速发展，给各行各业带来了方便与快捷。当然，学校教育也不例外，教育作为推动经济发展、促进就业、改善民生的重要途径，必须受到重点关注。计算机互联网与学校教育的结合一定会大大改善教学质量，提高教学效率。未来的教育一定是网络化教育，其优秀的资源共享、强大的组织能力、高效的师生互动功能是传统教学所不能媲美的。其中一个很重要的环节就是试题库的管理与考试系统。传统的考试需要人工出题、印刷试卷、考生考试、人工阅卷、统计成绩等繁琐步骤，耗费人力物力，并且工作量的增加也会或多或少导致评阅的错误，因此传统的方法在当代显得非常的笨重和低效。网上试题库和考试系统可以解决传统方式所达不到的高效阅卷、智能出题等问题，教师减�

1. 研究目的与意义（文献综述） 随着时代的发展，科技的进步，日历不仅在我们的生产、生活中必不可少，而且它的内容和形式也越来越丰富。在高速发展的现代社会，传统的日历在其功能和性能上已逐渐不能满足人们的生产生活，各种电子化的日历应运而生。本课题是基于一种EDA工具设计的智能数字日历，不仅具有传统日历年、月、日、星期、时、分、秒计时显示功能，同时，它还能智能化的判断当前的年份（平年和闰年）自我调整，另外它还加上了时间调整功能、整点报时功能和闹钟功能。它能满足了大多数人对日历功能的要求，大大的方便了人们的生活。 自从单片机的广泛运用，各种各样的多功能电子日历相继问世，目前，国内的数字日历技术向着超微型、超高效的方向发展，具有体积小，耗电小、计时精准、性能稳定、维护方便等特�

1. 研究目的与意义（文献综述） 直至今日，国内外的专家以及行业相关人士都在对功率回收液压泵试验台的研究进行积极且广泛的研究。国外在相关行业起步早，发展水平较高，尤其是对计算机测试技术的合理运用，让其在这个方面变得比较成熟，但由于某些原因，很难确切地了解到其技术核心。国内在此项研究上虽然起步晚，但在广大专家以及行业人士的努力之下，同样取得了极大的进展： 陈国安等设计了一种液压泵功率回收试验系统，并申请了专利。这种功率回收式反馈试验方法，在技术上和经济上有很多可取之处，特别适用于大功率液压泵性能试验，对提高试验经济效果有很大帮助。如果将这部分产生热能的功率加以回收利用，能量损失减小，将大大减小装机功率，达到节能、节约时间和成本的设计要求。 白国长等提出了一种机械�

1. 研究目的与意义（文献综述） 板料成形技术是重要的金属成形方法之一，广泛应用于工业领域，如：航空、航天、船舶、汽车等。在板料成形过程中，由于几何边界条件和摩擦条件等因素的影响，加载路径通常偏离线性路径，对于复杂形状零件成形、多工步成形等情况更是如此，时常出现破裂、起皱、回弹等成形缺陷[1],所以了解板料成形能力具有重要意义，作为判断板料成形能力的一个重要指标——成形极限图（FLD）[2],由金属薄板在各种应变状态时所能达到的极限应变值所构成的图形，能直观、清楚地表明薄板在冲压过程中的变形情况。零件变形接近或超过成形极限曲线即可冲裂[3],而变形范围在成形极限曲线下方的零件,表明不会出现零件报废的情况，因而通常采用成形极限图作为组织生产，比较最佳工艺以及冲压设计及选材的依据。 通常采�

1. 研究目的与意义（文献综述包含参考文献）With the deepening of China's internationalization, English, as the most common international language, is being used by more and more people. Learning and mastering English is the basic requirement for the national quality in the 21st century. English has become an important tool for learning cultural and scientific knowledge, acquiring information from all aspects of the world and conducting international exchanges. Vocabulary learning is an important part of English teaching. Wilkins, a foreign language scientist, once said, "Without grammar, ideas are difficult to express, but without vocabulary, nothing can be expressed at all." In the Compulsory Education English Curriculum Standards (2017), the Ministry of Education requires junior high school students to learn and use 1500-1600 English vocabulary and 200-300 fixed collocations or idioms when they graduate, and to be able to use vocabulary to describe things, behaviors

1. 研究目的与意义（文献综述包含参考文献）1.Introduction1.1 Research backgroundIndividual differences (IDs) have been studied for quite a long time, even pre-dating the Second Language Acquisition (SLA) research. Many recent studies have sought to uncover the underlying relationships between IDs and second language (L2) achievements. For example, many researchers have shown great interest in exploring why some learners are more successful than others. The core factors which were commonly included by many researchers in their research are language aptitude, motivation, personality, intelligence, learning strategies and age. The relevant factors related with learners are language aptitude, age, gender, learning motivation, anxiety, self-esteem, individual character, learning preference, learning strategies, intelligence and so on. Among these factors, most of them cannot be changed or it is hard to change them, which are called uncontrollable factors (Wen, 1993). Howeve

1. 研究目的与意义（文献综述包含参考文献）1. Introduction With the rapid development of science and technology, the popularity of mobile devices not only facilitates people#8217;s lives, but also creates better carriers for mobile learning. It is generally believed that mobile learning can occur at anytime and anywhere. Mobile devices used in mobile learning must be able to effectively present learning content and provide two-way communication between teachers and learners (Aleksander, 2006). With the popularization of smart phones, a variety of mobile learning softwares emerge in endlessly, which provide many conveniences for learners. 1.1 Need for the study According to A Research into Evaluation Indicator System of English Listening and Speaking Software (2009), English learning softwares can be divided into different categories, such as APPs of vocabulary skills training, APPs of listening and speaking skills training, APPs of reading skills training and APPs

1. 研究目的与意义 阅读被认为是日常生活和工作中非常重要的一项技能。对于大多数外语学习者来讲,通过与目的语会话者面对面交流进行学习的机会是非常有限的,因此,最方便的方法便是通过阅读与之接触。在外语测试中,阅读理解部分在整个测试中占了非常大的比重,由此可见其重要性。因此,设计出好的阅读理解试题是保证其测试成功的一个重要方面。大学期间，说到英语考试，通常绕不开两个种类：外国英文考试（托福、雅思等）和中国英文考试（四六级）。二者虽然都是英文考试，但是因为主办方和目的的不同，考察重点和题型都有所区别，对于打算参加的考生来说，备考的方式自然也要有所区别。本文将重点对比研究各项考试中的阅读理解这一题型。 本文将参考大量对雅思托福及四六级考试中阅读理解考查方法及效度进行研究的中外文�

1. 研究目的与意义（文献综述） Unmanned electric vehicle is a kind of intelligent vehicle that can feel the surroundings with various sensors and control the steering and speed of the vehicle based on the acquired information such as roads condition, vehicle locations and obstacles, which reduces the effort of human factors on driving safety. At the same time, unmanned electric vehicles only needs to use electricity instead of oil which contributes to serious environmental pollution. Moreover electric energy can be obtained from wide range of resources: such as hydro, wind, nuclear materials, solar, etc. With the continuous development of technology, more and more unmanned electric vehicles can be developed in the near future. In early 1980s, the US Department of Defense gave large-scale funding of ALV (Autonomous Land Vehicle) research. Unmanned vehicles were first successfully applied to the highway with high degree of structural environment, some of the representat