3 resultados para Formation process

em Dalarna University College Electronic Archive


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随着社会的发展,尤其是互联网的发展,很多语言每年都涌现出了不少新词汇。词语是每个语言最基本也是最重要的组成部分,因此分析这些新词汇的结构特点以及构词法是很有意义的。这篇文章分析了2014年出现在中文里的新词汇和它们的构词方式,论文的目的是为了更好地了解中文词汇的发展和特点。本文以《2014汉语新词语》中公布的2014年出现的新词汇作为语料进行分析,发现了以下两个主要特点:第一,合成法,派生法,缩略法是2014年产生的新词汇的主要构词方式;第二, 百分之七十二的新词汇是多音节词(包含三个或者三个以上音节),而百分之八十的是名词。这些特点说明中文词汇现阶段的特点和发展趋势,跟传统的中文词汇有不同之处。

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Today, large public investments are being made with the aim of creating and developing cooperation between businesses in inter-organizational networks. Such initiatives are commonly denoted cluster initiatives and their underlying purpose are to spur innovation and regional growth. Much research has been conducted in this field, but relatively few studies have examined the process of cluster initiatives. By following the case of a regional cluster project within the tourism industry in the region of Dalarna, Sweden, the objective of this thesis is to deepen the understanding of the formation and development process of cluster initiatives. The investigation has been conducted by examining two main themes; the internal relationships within the cluster initiative and the relationships between the cluster initiative and its external stakeholders, such as funding agencies, regional government and local businesses. The analysis is based on a legitimacy perspective and indicates that the coordinating body of the cluster initiative, the hub, principally deals with a legitimation process. What occurs within the cluster initiative, between the members themselves and between the members and the hub, is legitimation. This also applies to external relationships, between the hub and its external stakeholders. A prerequisite for the realization of its mission is that the hub obtain and sustain legitimacy; legitimacy for itself, for the other members, for the idea, for the different activities and for the industry as such.

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One of the first questions to consider when designing a new roll forming line is the number of forming steps required to produce a profile. The number depends on material properties, the cross-section geometry and tolerance requirements, but the tool designer also wants to minimize the number of forming steps in order to reduce the investment costs for the customer. There are several computer aided engineering systems on the market that can assist the tool designing process. These include more or less simple formulas to predict deformation during forming as well as the number of forming steps. In recent years it has also become possible to use finite element analysis for the design of roll forming processes. The objective of the work presented in this thesis was to answer the following question: How should the roll forming process be designed for complex geometries and/or high strength steels? The work approach included both literature studies as well as experimental and modelling work. The experimental part gave direct insight into the process and was also used to develop and validate models of the process. Starting with simple geometries and standard steels the work progressed to more complex profiles of variable depth and width, made of high strength steels. The results obtained are published in seven papers appended to this thesis. In the first study (see paper 1) a finite element model for investigating the roll forming of a U-profile was built. It was used to investigate the effect on longitudinal peak membrane strain and deformation length when yield strength increases, see paper 2 and 3. The simulations showed that the peak strain decreases whereas the deformation length increases when the yield strength increases. The studies described in paper 4 and 5 measured roll load, roll torque, springback and strain history during the U-profile forming process. The measurement results were used to validate the finite element model in paper 1. The results presented in paper 6 shows that the formability of stainless steel (e.g. AISI 301), that in the cold rolled condition has a large martensite fraction, can be substantially increased by heating the bending zone. The heated area will then become austenitic and ductile before the roll forming. Thanks to the phenomenon of strain induced martensite formation, the steel will regain the martensite content and its strength during the subsequent plastic straining. Finally, a new tooling concept for profiles with variable cross-sections is presented in paper 7. The overall conclusions of the present work are that today, it is possible to successfully develop profiles of complex geometries (3D roll forming) in high strength steels and that finite element simulation can be a useful tool in the design of the roll forming process.