3,591 research outputs found
Experimental investigation of Phase Equilibria of Partial Ternary systems with Rhenium
摘要 镍基高温合金具有高强度、优良的耐热性和良好的耐腐蚀性,被广泛应用于航空航天、国防军事、核能等重要领域。迄今为止,镍基高温合金的添加元素达到了十多种,熔点高、原子半径大的元素如Co,Re,Ru,Mo,W等的添加,能起到很好的固溶强化作用,改善高温力学性能。然而高熔点元素的过量添加导致拓扑密排相的产生,降低镍基高温合金的疲劳寿命、塑性、韧性等力学性能。相图作为合金设计的基础,能够很好的指导镍基高温合金的成分设计。然而,由于Re,Ru,W等元素价格贵,熔点高,对其进行实验研究比较困难。截至目前,由Co,Re,Ru,Mo,W元素组成的三元系相图仍未发现研究报道。因此本研究对Co,Re,Ru,M...Abstract The Ni-base superalloys are widely used in various fields, especially in the aerospace field due to their high strength, good heat resistance ability and corrosion resistance ability and so on. Till now, a dozen elements have been added to Ni-base superalloys. Element with high melt point and big atomic radius, such as Co, Re, Ru, Mo, W et al, have a good solution strengthening efect and...学位:工程硕士院系专业:材料学院_工程硕士(材料工程)学号:2072013115011
How to Improve Employee Engagement—Based on Employee Engagement Questionnaire Survey of KNBW
全球化竞争,技术创新,业务转型……,在工业4.0、“互联网+”的经济发展时代到来之际,企业面临的市场竞争环境愈发激烈和多变,促使企业更加重视对员工的激励和保留,并希望员工可以全身心的投入到工作中,提高员工的敬业度,为公司创造价值。 员工敬业度是一个和组织行为学、心理学以及人力资源管理都密切相关的一个主题。近年来学者们的理论研究和咨询机构的实践研究都发现:员工敬业度对企业的经营业绩起到重要作用。高敬业员工可以为企业带来更满意的客户和更好的营业收入。这也是越来越多的企业开始重视和关注员工敬业度的原因所在。由于员工敬业度的研究时间相对有限,目前还没有统一的定义和系统完善的理论体系。 本文梳理了近...Global competition, technology innovation and business transformation… Along with the age of Industry 4.0 and Internet +, the fierce and unpredictable commercial environment makes us focus more on employee motivation and retention. Employees are expected to exert effort to work, have a high level of engagement and create value for the company. Employee engagement has close relationship to organiz...学位:工商管理硕士院系专业:管理学院_工商管理硕士(工商管理硕士)学号:1792012115096
The Relationship of Environmental Factors with Community Structures and Diversities of Microorganisms in Activated Sludge from Wastewater Treatment Plants
随着我国社会经济的飞速发展和城镇化进程的加快,大量肆意排放的废水造成水体严重污染,导致“水危机”日趋严重。废水在排入水体前,应首先由污水处理厂进行处理。较之于增加污水处理厂数量需要耗费大量资金成本,提高现有污水处理设施的废水处理效率至关重要。活性污泥法是污水处理厂应用最广泛的废水处理方式之一。由于在活性污泥系统中,微生物是去除污染物的主体。因此,深入了解活性污泥中微生物的群落结构与功能,理解其时空分布格局及受控机理,对于深化认识污水处理系统的本质,进而提高污水处理效率具有重要意义。此外,由于活性污泥中还存在着大量的重金属、病原微生物和寄生虫卵等,因此污水处理厂每年产生的巨量剩余污泥的处理和处置...A large amount of wastewater discharged has led to the continuous water pollution and brought about a severe “water crisis” as the rapid economic development and accelerated urbanization process Wastewater should be treated by wastewater treatment plants (WWTPs) before discharged. Improving the efficiency of WWTPs have a significance on wastewater treatment since much capital is needed by increasi...学位:理学硕士院系专业:生命科学学院_微生物学学号:2162010115238
不同经济发展水平区域物流与经济增长的协整关系研究
根据协整检验和因果关系检验等计量方法,利用中国各省1991~2007年物流发展水平和国内生产总值的年度数据,将31个省(市、自治区)按经济密集度不同分成三大类地区,并对其物流和经济增长的关系分析进行了实证分析。实证结果表明:三个区域的物流与经济增长均存在协整关系,发达的一类地区两个变量存在双向Granger因果关系,而后两类地区两个变量仅存在单向的Granger原因。国家自然科学重点资助项目“中国城市化进程的资源环境基础研究”(40535026
Large-eddy simulation of flows past a flapping airfoil using immersed boundary method
The numerical simulation of flows past flapping foils at moderate Reynolds numbers presents two challenges to computational fluid dynamics: turbulent flows and moving boundaries. The direct forcing immersed boundary (IB) method has been developed to simulate laminar flows. However, its performance in simulating turbulent flows and transitional flows with moving boundaries has not been fully evaluated. In the present work, we use the IB method to simulate fully developed turbulent channel flows and transitional flows past a stationary/plunging SD7003 airfoil. To suppress the non-physical force oscillations in the plunging case, we use the smoothed discrete delta function for interpolation in the IB method. The results of the present work demonstrate that the IB method can be used to simulate turbulent flows and transitional flows with moving boundaries
Quality Analyses and Improvements of Projected Capacitive Touch Sensors During Research and Development of New Products
在新产品研发阶段,产品质量管控标准尚不完善,制程良率靠抽检方式来评测,而成品良率则靠全检方式进行评测,导致各制程的产品良率和成品良率存在差距。因此,在研发阶段进行质量分析与管控,为量产阶段的质量管控体系打下基础。本论文针对投射式电容触控传感器在新产品研发阶段存在的问题,结合各制程良率和成品良率数据,对质量现状进行分析并展开研究,由此提出相应的改善对策,确认执行效果框架,主要研究工作和结果总结如下: (1)通过对各制程良率的现状分析,确定需要对四个制程,即大气压膜、曝光、显影和蚀刻的不良原因进行重点分析,进而确定改善方案。针对大气压膜制程干膜附着力差问题,进行实验设计研究,取得干膜与制程参数的...Products are finished after all of the processes. The quality of finished products depends on every process. Product quality system is far from perfect during research and development of new products. At present, the manufacture mode is generally roll-to-roll. The yield of every process is evaluated by random inspection, while the yield of finished products by full inspection, leading to a large g...学位:工学硕士院系专业:材料学院_材料学学号:X201219303
A Semiotic Analysis of College Students' Dormitory Culture: Based on the Study of M University
大学生宿舍文化日益受到研究者和管理工作者的重视。从学生的角度,宿舍文化对大学生的心理健康和人格发展具有重要意义;从高校的角度,宿舍文化是校园文化的子文化,是良好校风建设、和谐校园的基础。 符号是表达意义和理解意义的工具,文化是社会(包括其中个体成员)意义活动的集合,文化符号学就是把文化视为一种符号或象征体系的意义研究之学。论文以M校宿舍文化作为个案,采用质性研究的方法从文化符号学的视角进行研究,主要对11间学生宿舍及其成员深度访谈,研究者通过访谈与受访者共同提取宿舍文化的符号表征,探寻宿舍文化符号产生和发展的过程,并基于宿舍成员所处的文化环境与受访者共同解读符号背后的意义。 论文将提取的M...The college dormitory culture is increasingly valued by researchers and management workers. From the perspective of students, the dormitory culture is of great significance to the mental health and personality development of college students. From the point of view of post-secondary education schools, the dormitory culture is subculture of campus culture as well as the foundation of campus climate...学位:教育学硕士院系专业:教育研究院_高等教育学学号:2572014115183
Structure design of Fe/N/C electrocatalysts for oxygen reduction and its active sites study
热解型Fe/N/C作为最具潜力的非贵金属氧还原催化剂,其综合性能的进一步突破,对于推动低温燃料电池商业化应用具有极其重要的意义。不过,Fe/N/C催化剂仍面临着几方面的挑战。首先是传质扩散问题。Fe/N/C催化剂在燃料电池阴极的载量较高,其传质的难度远高于商业化的Pt/C(厚度100μmvs.10μm)。其次是对其活性位结构的认识。对活性位和反应机理的深入认识有助于进一步理性设计和提高Fe/N/C催化性能。然而,复杂、非均相结构、缺乏合适的表面表征技术和谱学技术,使得其活性位和催化机理研究止步不前。基于此,本文的工作主要分两部分展开:1)通过设计Fe/N/C催化剂的结构改善传质,包括制备复合碳...Pyrolyzed Fe/N/C is one of the most promising non-precious-metal catalysts for the oxygen reduction reaction (ORR), which is supposed to boost the commercialization of proton exchange membrane fuel cells (PEMFC). In spite of recent significant technological advances, a couple of major challenges remain on the way to the widespread application of Fe/N/C catalyst. The first challenge is mass transfe...学位:博士后院系专业:化学化工学院_物理化学学号:201417002
Construction and research of Medical College Online Examination System based on load balance
信息技术、网络技术以及计算机技术都在飞速发展,在当前情况之下,传统的医学教学方法和考核办法面临着日益严峻的挑战。考试不仅是为了甄别学生的学习效果如何,更是反映学生综合素质的一种手段。然而,学校引进的在线考试系统多为通用性的考试系统,在试题和选项上都是传统的文字形式,由于医学院校侧重技能方面的考查,所以本系统将在试题题干和选项的表现形式上进行扩展,因此有必要针对医学院在线考试系统进行设计和研究。 本文首先对相关的技术和理论展开研究,分别介绍了五种关键性技术,最为重点的是对负载均衡技术进行了研究,对负载均衡及其算法策略原理进行了详细介绍。在需求分析层面,本文深入到医学院在线考试系统当中,对其中的...With the development and mature of information technology, network technology and computer technology, the traditional medicine teaching and assessment methods face a growing challenge. Examination is not only a mean to evaluate students’ learning effect but also a mean to reflect the comprehensive quality of students. The introduction of the colleges’ online examination system is generic exam sys...学位:工程硕士院系专业:信息科学与技术学院_工程硕士(计算机技术)学号:X200822104
不同脂肪源对异育银鲫的生长、体组成和肌肉脂肪酸的影响
配制了十种等氮等能的饲料饲喂3.53 g的异育银鲫幼鱼12周,探讨异育银鲫对不同脂肪源的利用效果。十种饲料中分别添加8%的鱼油(FO)、椰子油(CNO)、玉米油(CO)、亚麻油(LO)、大豆油(SO)、菜籽油(RO)、1∶1鱼油-椰子油(FCNO)、1∶1鱼油-玉米油(FCO)、1∶1鱼油-亚麻油(FLO)和1∶1∶1∶1鱼油-椰子油-玉米油-亚麻油混合油(MIX)。每组饲料三个平行,每个平行30尾。实验在循环水养殖系统中进行,水温控制在(24±1)℃。结果表明,在单一脂肪源中,豆油组和椰子油组的增重率最高,其次是菜籽油组,鱼油、玉米油和亚麻油组的增重率最低。与相应的单一脂肪源相比,饲料中鱼油与椰子油、玉米油或亚麻油1∶1混合后使用提高了异育银鲫的生长。摄食不同脂肪源饲料的异育银鲫血清生化指标、各组织的水分和脂肪含量差异不明显(P>0.05)。肌肉脂肪酸与饲料脂肪源呈明显正相关。摄食豆油和菜籽油饲料的鱼体肌肉中20:4n-6较高,而摄食亚麻油饲料的鱼则含有较高的20:5n-3和22:6n-3,表明异育银鲫具有转化18:2n-6和18:3n-3为高不饱和脂肪酸的能力。从实验可以看出,豆油、椰子油和菜籽油是异育银鲫饲料中良好的脂肪源
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