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    找到约2788个结果。

    基因表达谱数据分析开题报告

    1. 研究目的与意义、国内外研究现状(文献综述)1.本课题研究目的及意义基因在遗传学上有重要作用,基因决定了物种形态。基因表达谱能够描绘特定细胞或组织在特定状态下的基因表达种类和丰富信息,其最终目的是通过从基因实验获取的基因表达谱数据来探讨在某一特定生物学状态下的预测基因调控功能。2.本课题在国内外研究状态及应用前景现如今,基因芯片技术已经有了巨大的影响,一个芯片能够同时测出上千万及基因的表达情况。基因芯片数据应该根据实验的目的和数据的结构进行分析。差异分析的目的是检测组间差异表达基因,聚类分析能将基因分类成不同的群组。之前的聚类都是在离散情况下,以基因表现型的相似性为基础。例如,来自不同机构的组织[2],一个特定药物处理之后的时间点[3],一种药物感染的剂量[4]。最常用的方法

    新能源汽车车身异种金属冲击连接工艺分析开题报告

    全文总字数:13327字1. 研究目的与意义(文献综述) Research purpose With the developmentand progress of science and technology, we need to have a more clear andintuitive understanding to new energy automobile body dissimilar metal welding,enrich the research of its existing .Because the current single metal or alloyis difficult to meet the requirements on the properties of materials in a broadrange of areas. So the welding of dissimilar metal must occupy an importantposition in the manufacturing industry. And our car industry as the backbone ofthe manufacturing industry. Obviously dissimilar metal welding has a broadapplication prospect in the automotive industry. But the traditional way ofwelding is difficult to achieve good welding of dissimilar metals .Therefore,we are bound to optimize the connection of automobile body through the weldingwhich means we need to deepen the research on the foreign metal welding ofautomobile body. Therefore, the purpose of this

    残余应力对装甲车车身成型性影响分析和仿真设计开题报告

    全文总字数:10516字1. 研究目的与意义(文献综述) 1.Purpose and significance (including analysis ofresearch status at home and abroad) 1.1 Purpose and significance Cold-formedsteel is made of hot-rolled or cold-rolled steel sheet as raw material andprocessed by roll-bending at normal temperature to produce variouscross-sectional shapes. Cold-formed steel itself has many advantagessuch as uniform cross-section, low energy consumption and high economicbenefits. At the same time, it has high versatility and safety. Therefore,armored car bodies are increasingly using high-strength cold-formed steel. Whetherit is a hot-rolled steel sheet or a cold-rolled steel sheet, the correspondingresidual stress will be generated during the processing of the steel sheet, andthe current research on cold forming often ignores the residual stress in thesteel sheet and directly simulates the cold bending process. This is inaccurate.The existence of residual stress during the processing

    双层公交客车制动系设计开题报告

    全文总字数:12650字1. 研究目的与意义(文献综述) The braking system is an important part of the car. It is used to forcibly slow down or stop the car while driving, to keep the speed of the car driving downhill stable, and to keep the parked car in the same place (including on the slope).According to relevant information, in traffic accidents caused by the problem of the vehicle itself, the accident caused by the failure of the braking system is 45% of the total. Double-decker buses are buses with upper and lower levels of passenger space. They have the advantages of large passenger capacity and saving parking space. Although their length and width are almost the same as ordinary buses, but because of an additional layer, the height of the vehicle is higher than other vehicles, and this makes this type of vehicle carry more than other models, However , because the vehicle body is huge and the center of gravity of the vehicle is higher than that of ordinary buses, th

    基于STM32的脱机程序下载器设计与制作开题报告

    全文总字数:4056字1. 研究目的与意义(文献综述) 早期的单片机开发时使用仿真器开发应用项目,这么做是因为用户需要将开发好的应用程序交给单片机工厂制作掩模。程序一旦写进就不可修改,于是使用仿真器解决这个问题,用软件来模拟目标系统中MCU(MicrocontrollerUnit)的运行情况。如此做的缺点是无法实现100%的模拟硬件,出现问题时无法确定是仿真器的问题还是目标板的问题,加大了开发的难度和时间消耗。 随着FLASH技术的日渐成熟,现在许多MCU(Microcontroller Unit)内部集成了FLASH存储器,单片机允许内部运行的程序修改FLASH存储器的内容,这样就使单片机开发不再需要仿真器。FLASH存储器可反复擦除高达10万次以上,因此开发过程中不必担心寿命问题。同时,直接在目标版上运行应用程序,是在真实的硬件环境中进行的,相对于以前的仿真器开发

    水泥预分解窑系统表面散热计算软件的研究与开发开题报告

    1. 研究目的与意义(文献综述) 热工测量又称为:热工标定。在水泥工业中,它是了解掌握和研究水泥窑生产运行状况的基础,对于了解具体水泥回转窑系统的生产状况有很大帮助。目前,国内外的水泥科技工作者将热工测量作为探测水泥窑运行状况以及进行水泥技术科研开发和优化生产的重要手段之一。热工测量是指对于有关温度、压强、流速、流量、含尘浓度、湿度等重要的热工参数进行现场检测。而通过热工测量则可以对水泥熟料烧成过程中的热量平衡与物料平衡进行计算,以此实现对水泥熟料烧成过程的优化控制与操作[1,2]。 自从上个世纪以来,水泥窑系统的技术设备与生产状况发生了重大变化,上个世纪五十年代出现了悬浮预热窑(SP窑),而到了上个世纪七十年代,又有预分解窑(NSP窑)诞生并且得到了迅速的发展。在过去的传

    基于深度学习的中药饮片识别开题报告

    1. 研究目的与意义(文献综述包含参考文献)一、系统开发的背景及意义生活中,由于中医当中的中药种类繁多,样子各异,记住这些中药名需要耗费相当大的精力。为了减轻识别中药饮片的负担,针对不同的中药特点进行识别,提高识别的准确率变得尤为中药。本项目旨在利用人工智能和机器视觉技术,提出一种检测中药饮片地新方法,帮助人们快速并准确地识别中药饮片。本项目以中药饮片为研究对象,通过机器视觉采集图片大数据,建立图像数据库,通过对中药外在性状特征的分析,以深度学习为手段,研究建立孪生神经网络模型来实现定位检测,类别识别等功能,以提高中药快速识别的准确率。学习并掌握相关开发工具和应用软件,理解各算法的设计过程。通过对毕业论文的撰写过程,学生的语言文字组织能力、表达能力以及层次分析、

    雅思阅读理解测试信度及可操作性研究—以”屠鸭联盟”及”我预测你高分”为例Reliability and Operatability of IELTS Reading Comprehension Test

    1. 研究目的与意义(文献综述) The recognition of IELTS increased dramatically, especially in China Mainland. It is reported that the amount of IETLS candidates exceeds 3 million in 2016. Due to the specialism of text paper arrangement in IETLS, a large number of IELTS training school emerged everywhere and developed dramatically. There are many different types of questions in reading part, especially for multiple choice. The questions not only focus on the details in passages, but also pay much attention to the main idea of whole passage. Because of the large difference between Chinese and western thinking, it still existed in the language text paper arrangement. Therefore, the application of the text-prep tracks is more potential than domestic language text. This is one of the most significant reasons in the flourish of training industry. Most of the students could get their ideal marks with the training like this even without the equivalent language ability. Namely, it

    生词释义方式对英语学习者词汇习得的影响 The Effect of Mode of Unknown Word Interpretation on EFL Learners Vocabulary Acquisition开题报告

    1. 研究目的与意义(文献综述包含参考文献)2.Literaturereview2.1twowaysoflearningvocabulary:intentionvs.IncidentalVocabularycanbelearnedintwoways:intentionlearningandincidentallearning.Sincethebeginningofthe20thcentury,thetermsofincidentalandintentionallearninghavebeenwidelyusedinthepsychologicalliteratureandappliedlinguistics.Incidentalvocabularylearningfirstappearedintheresearchreviewofpsychologyintheearly20thcentury.Later,basedonresearchintohowchildrenlearnvocabularyintheirnativelanguage,incidentalvocabularylearningwasputforwardbyNagyandHerman(1985).Theyproposedthatthevastmajorityofvocabularywordswerelearnedgraduallythroughrepeatedexposuresinvariousdiscoursecontexts.Consequently,NagyandHerman(1987)arguedthatteachersshouldpromoteextensivereadingbecauseitcouldleadtogreatervocabularygrowththananyprogramofexplicitinstructionaloneevercould.Asmentionedprevious,intentionalvocabularylearningisaprocessinwhichstudentsacquiresvocabularybysomeintentionalways,suchasmemorizingwor

    Characterization based on ECPT technique for metal surface corrosion开题报告

    1. 研究目的与意义(文献综述包含参考文献)Our industry today is highly concern with corrosion as a major problem, since it involves a high amount of mechanical failure and huge sums of money loss are encountered. In a laboratory way, corrosion has been simulated and modelled as pure metal loss with defined shapes or regions. However, real corrosion has chemical and physical changes, along with electrical and thermal property changes in the coating layer that should be taken into account in corrosion characterization [1]. A review of current literature shows that thermography is applicable to a wide range of materials [2]. Thermography in non-destructive testing and evaluation (NDTE) technique can be divided into two categories, which are; the passive and active approaches. The passive approach tests materials and structures which are naturally occurring at different (often higher) temperatures than the ambient background, while in the case of active thermography, an

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