73 research outputs found

    Theory and research method of LG/LC Rapid Prototyping

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    摘要本文对快速原型研究中的激光熔覆LC(lasercladding)、LG(laser/LENSGenerating)两种方法进行了理论上的探索和研究,对LG方法建立数学模型,从理论上推导出了在无支撑的情况下能直接成型的最大角的数学公式,即原型外缘与水平面的最小夹角的数学公式,分析了各种因素对夹角的影响,利用ABS材料,通过实验验证该数学推导理论的正确性;并且利用Matlab模拟了激光熔覆成型过程中各种因素对熔池深度的影响。这种数学公式与理论对LG、激光熔覆方式实际的设计、制造过程起到重大的指导作用。本论文的主要研究工作有:分析快速原型技术中各种方法的原理及各自的特点,确定对LG、激光熔覆制造...ABSTRACT The two kinds of methods of Rapid Prototyping(RP), Laser Cladding(LC) and Laser Generating (LG) are studied theoretically in this paper. In the LG process without support material, the mathematical model was used to calculate the minimal angle between prototype outward edge and horizon is deduced. And how the angle value is influenced by various parameters is analyzed. The experim...学位:工学硕士院系专业:物理与机电工程学院机电工程系_精密仪器及机械学号:20022900

    The overview of rapid prototyping technique

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    【中文文摘】在研究快速原型技术发展历史和现状的基础上,介绍了快速原型制造的基本原理,重点介绍几种发展较成熟的RP技术的基本原理,分析RP技术的特点,并探讨其应用价值和发展前景,提出了目前发展快速成型的基本观点和未来发展趋势。 【英文文摘】Based on the history and development of rapid prototyping technique,the principles of Rapid Protyping(RP),especially several developed techniques,are introduced.The characteristics of RP techniques are analyzed and the opinions about future development tendency and prospect are put forward.福建省自然基金项目(k32014);; 国家留学回国人员基金资助项目(k3003

    Development and Application of Micro-Electro-Mechanical System

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    【中文文摘】微机电系统是在微电子技术基础上产生和发展起来的多学科交叉的前沿科学研究领域 ,是面向 2 1世纪的高新科技 .介绍了微机电系统产生的背景影响、组成特征和基础研究内容 ,综述了微机电系统技术基础所涉及的材料、微机械设计和模、微细加工技术以及微封装与测试等领域 ,并对微机电系统的应用、典型的微器件、国内外的发展现状及前景进行全面分析 .在此基础上 ,论述了MEMS技术目前存在的问题和未来发展的趋势 【英文文摘】Micro-Electro-Mechanical System(MEMS) developes on the basis of microelectronics.It is a scientific researches frontier of multi-disciplines and a high technology in the 21st century.This paper presents the background,characteristics and basic research.The principal techniques of MEMS such as material,design and simulation,micromachining,packaging and testing are reviewed,Typic microapparatus,application prospect and the state-of-art of MEMS are also discussed in this paper.Furthermore,some points of view of developing on MEMS in the future are put forward

    The Application of PLC in Pneumatic Control Electrode Board Cutting Machine

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    【中文文摘】本文详细阐述了气动控制系统、光电检测、可编程控制器在气动电极板剪切机中的应用。 【英文文摘】The pneumatic control system,optoelectronic detection system,the application of PLC in pneumatic control electrode board cutting machine was introduced in detail

    SARS-CoV N蛋白与人冠状病毒HCoV-OC43和HCoV-229E的交叉反应表位及特异表位的确定

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    为确定SARS-CoV N蛋白的特异抗原表位,对3种人冠状病毒SARS-CoV、HCoV-OC43和HCoV-229E N蛋白之间的交叉免疫反应进行了系统研究。构建了分别表达SARS-CoV、HCoV-OC43和HCoV-229E N蛋白的重组痘苗病毒,并制备了相应的小鼠免疫血清。用间接免疫荧光方法,检测了3种N蛋白的表达及其与3种冠状病毒免疫动物血清和SARS病人恢复期血清之间的反应。与此同时,用Western blot方法分析了原核表达的39个不同区段的SARS-CoV N蛋白与3种冠状病毒动物免疫血清和SARS病人恢复期血清之间的交叉反应性。免疫荧光检测结果表明,SARS-CoV、HCoV-OC43和HCoV-229E3种病毒的N蛋白在重组痘苗病毒感染的HeLa细胞中均可以特异表达;3种N蛋白之间存在明显交叉免疫反应。Western blot结果显示,SARS-CoV N蛋白的表位主要位于30~60aa、170~184aa、301~320aa和360~422aa;与HCoV-OC43的交叉反应表位主要位于30~60aa、90~120aa、204~214aa和320~360aa;与HCoV-229E的交叉反应表位主要位于30~60aa、150~160aa和301~360aa。含SARS-CoV N蛋白特异表位的重组肽N155b(60~214aa)和N185(30~214aa)只与SARS病人恢复期血清和灭活SARS-CoV免疫小鼠的血清反应,而不与灭活HCoV-OC43和HCoV-229E免疫的山羊血清产生交叉反应。上述结果为使用SARS-CoV N蛋白抗原进行特异诊断试剂的研究,提供了重要的实验依据

    第十八届美国理论与应用力学大会总结

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    1会议概况2018年6月5—9日,第18届美国理论与应用力学大会(18th U.S. National Congress of Theoretical and Applied Mechanics, USNCTAM2018)在美国芝加哥召开.本次大会由美国力学国家委员会和中国力学学会联合主办,旨在探讨和交流近四年世界范围内在理论和应用力学领域的基础研究、创新技术的最新进展,吸引了来自世界各地的近千名专家学

    Optimization of separation methods and culture system of chicken embryonic stem cells in vitro

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    背景:胚胎干细胞是从动物早期胚胎的内细胞团或原始生殖细胞分离出来的具有发育全能性的一种未分化的无限增殖细胞系。而鸡胚胎干细胞则是从X期鸡胚的胚盘分离而来。目的:优化鸡胚胎干细胞分离方法和离体培养体系。方法:采用滤纸纸环-发环的方法从X期鸡胚分离胚盘细胞,并采用STO细胞作为饲养层和大鼠肝细胞(brl)条件培养基(CM)+细胞因子作为离体培养体系对分离的胚盘细胞进行培养。结果与结论:滤纸纸环-发环法获得的完整胚盘率为75%~85%,克隆形成率约为50%。brl-CM+饲养层培养体系,鸡胚胎干细胞可传至7代,而brl-CM+饲养层+细胞因子培养体系,鸡胚胎干细胞可传至25代。分离到的鸡胚胎干细胞,经碱性磷酸酶染色、SSEA-1染色鉴定,表明鸡胚胎干细胞处于未分化状态。提示,实验不仅优化了鸡胚胎的分离方法,获得完整且杂质少的胚盘,而且进一步优化了鸡胚胎干细胞体外培养体系。BACKGROUND:Embryonic stem cells are undifferentiated permanent cell line derived from inner cell mass cells and primordial germ cells of animal's early embryos.Chicken embryonic stem cells are derived from the blastodermal of a X-stage embryo.OBJECTIVE:To optim the separation method and in vitro cultural system of chicken embryonic stem cells.METHODS:The X-stage chicken embryos were isolated by using a small square of ?lter paper with a hole punched in the center,and the blastodermal cells were isolated by using the hair loop.STO cells were used to make feeder layer;at the same time,BRL-CM and cytokine were also used for chicken embryonic stem cells in vitro cultural system.RESULTS AND CONCLUSION:The filter paper loop and the hair loop could obtain complete the blastoderm,and the successful percentage was 75%-85%.The colony formation rate was about 50%.After culture in the BRL-CM + feeder layer + cytokine culture system,the passage of CES cells is the seventh generation;BRL-CM + feeder layer + cytokines,cultured chicken embryonic stem cells could passage to the 25th generation.Isolated chicken embryonic stem cells were in an undifferentiated state detected by alkaline phosphatase staining and SSEA-1 staining.The findings indicate that this experiment not only optimized the isolation method of chicken embryonic stem cells to obtain complete and pure embryos,but also further improved the in vitro culture system of chicken embryonic stem cells.国家973项目(2009CB941600)资助;国家自然科学基金项目(31072101)资助---

    两院院士郑哲敏:爱国情怀是科学研究的重要动机

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    郑哲敏以光辉的一生,谱写了一首科技工作者不忘初心、牢记使命的壮丽诗篇,为中国力学事业留下了一座丰碑。2013年1月,北京人民大会堂。我国著名力学家、中国爆炸力学的奠基人和开拓者之一,中国科学院院士、中国工程院院士郑哲敏获颁2012年国家最高科学技术奖证书

    碳纳米管小球型材吸附铀酰离子的性能研究

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    以聚苯乙烯树脂小球为前驱体,采用气相沉积法合成了碳纳米管小球型材,将其应用于对放射性废水中铀酰离子的吸附。测试结果显示,当pH处于4~8时,吸附量达到最大值。铀酰离子的吸附为Langmuir单层吸附,理论最大吸附量为73.42 mg/g。同时吸附动力学分析表明,该吸附为拟二级化学吸附
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