• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1623
  • 315
  • 292
  • 274
  • 216
  • 73
  • 56
  • 48
  • 30
  • 26
  • 11
  • 9
  • 8
  • 7
  • 7
  • Tagged with
  • 3584
  • 1299
  • 430
  • 395
  • 341
  • 252
  • 222
  • 206
  • 199
  • 197
  • 184
  • 167
  • 166
  • 165
  • 147
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

The research of Taiwan IC assembly competence strategy

Wu, An-Ching 23 June 2004 (has links)
Taiwan IC assembly industry has became mature. from survey of World Journal about the top 100 entrepreneurs,average profit is around 1.3%, that reached the bottom of valley within these 17 years and it drive the industry into low cost competitive environment with fast cost erosion, it announces ¡§the low profit times is coming¡¨. IC assembly house entry barrier is low. normally 50 sets wire bond are treated as a start point with 10 millions NTD investment and products covered dual in line,small outline,quad flat package,tape carrier package,ball grid array,image sensor,chip on film,ball bumping.While similar products is produced within competitors, the low cost strategy is selected.it caused Amkor / ASE / SPIL trying to merge some small companies in these years, aim to reach economical scale and cost benefits .in the same time,Main China ic-assembly capability is built and the impact will be appeared gradually . by means of suitable competition theory,we select 8 major issues as study topics and through interview with several ic assembly president /vice-presidents, this study aim to find out the competitive advantage and workable managerial strategy tool in this low profit times,and hope to contribute to Taiwan IC assembly house.
42

Study of the advanced bonding layout of stack chip assembly

Tseng, Jen-Te 07 February 2007 (has links)
Modern development of electronic devices requires the integration of more and more powerful functions within the same amount of space. However, this is accompanied by increased difficulties within the manufacturing and packaging processes. A proposal for the arrangement of wire connecting is suggested. In this work, which is to replace the multi-tier design with conventional high & long wire bonding. The advance of bonding layout of the stack die HSBGA (Heat Slug Ball Grid Array) chip assembly can enhance wire bonding with electrical performance by shortening wire length. This promises a better thermal performance of thermal consumption between the function die and heat slugs. This analysis includes simulations of electrical and thermal performance, as well as simulations of drawing layout for an actual production, the bonding looping parameters optimization, and SEM analysis to confirm the results. Based on the above analyses, the results reveal three advantages of the proposal of ¡§Advance bonding layout of chip assembly¡¨ which are: (1)reduction of 40% thermal resistance, (2)£cJC voltage insertion loss improvement of 30~40%, and (3)reduction of the gold wire length from 4.5mm to 3mm, saving 1/3 of gold wire consumption. Overall, assembly costs can be reduced by 6%.
43

Experimental study of the residual stress-induced self-assembly of MEMS structures during deposition

Kim, Sang-Hyun 01 November 2005 (has links)
The possibility of using residual stresses favorably as a means of self-assembling MEMS during material deposition is experimentally investigated. Two atomic force microscope cantilevers are placed in contact at their free ends. Material is isothermally electroplated onto one (the deposition) cantilever, but no material is deposited onto the other (spring) cantilever. The deposited layer contains residual stresses that deform the deposition cantilever. The deposition cantilever in turn deforms the spring cantilever, thereby doing work in the spring cantilever and proving that the two structures can selfassemble during deposition processing. An insoluble nickel electroplating process and an all-sulfate nickel solution are used for the deposition. The deflection of the selfassembled cantilevers is measured in-situ as a function of the deposited thin film thickness through the optical method of atomic force microscopy. The experimental results are compared to an analytical model which consists of Euler-Bernoulli beam theory that is modified to account for moving boundaries as the material is deposited. The model accounts for the through-thickness variation of the intrinsic strain during the electroplating. Closed-form solutions are not possible, but numerical solutions are plotted for the cantilever deflection and work on the spring cantilever as functions of the deposition thickness.
44

Implementation of Flexible Automatic Assembly in Small Companies - Flexibility and Process demands

Johansson, Roger January 2002 (has links)
No description available.
45

Primary school assembly perspectives and practices : implications for pupils' spiritual development.

Smart, Diane C. January 2001 (has links)
Thesis (EdD)--Open University.
46

Crafting ordered structures of nanomaterials via flow-enabled self-assembly (FESA) and controlled evaporative self-assembly (CESA)

Li, Bo 08 June 2015 (has links)
The use of spontaneous self-assembly as a lithography free means to construct well-ordered, often intriguing structures has received much attention for its ease of producing complex, centimeter-scale structures with small feature sizes. These self-organized structures promise new opportunities for developing miniaturized optical, electronic, optoelectronic, and magnetic devices. One extremely simple route to intriguing structures is the evaporative self-assembly of nonvolatile solutes from a sessile droplet on a solid substrate. However, flow instabilities during the evaporation process often result in non-equilibrium and irregular dissipative structures (e.g., randomly organized convection patterns, stochastically distributed multi-rings, etc.). Therefore, in order to fully control the evaporative self-assembly of solutes, two strategies, namely, controlled evaporative self-assembly (CESA) and flow-enabled evaporative-induced self-assembly (FESA) were developed to create ordered structures of various nanomaterials. First, hierarchical assemblies of amphiphilic diblock copolymer (i.e., polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP)) micelles were crafted by FESA. The periodic threads comprising a monolayer or a bilayer of PS-b-P4VP micelles were precisely positioned and patterned over large areas. Second, highly aligned parallel DNA nanowires in the forms of nanostructured spokes over a macroscopic area were created via evaporative self-assembly (CESA) by subjecting DNA aqueous solution to evaporate in a curve-on-flat geometry composed of a spherical on a flat substrate. Third, large-scale aligned metallic nanowires templated by highly oriented DNA were produced by flow-enabled self-assembly (FESA). A simple yet robust swelling-induced transfer printing (SIT-Printing) technique was developed to transfer ultralong DNA nanowires onto the desirable substrate. Subsequently, the resulting DNA nanowires were exploited as templates to form metallic nanowires by exposing DNA nanowires preloaded with metal salts under oxygen plasma. Moreover, DNA nanowires were also employed as scaffold for aligning metal nanoparticles and nanorods. Fourth, colloidal microchannels (i.e., cracks) on a large scale were yielded by fully controlling the drying process of colloidal suspensions via flow-enabled self-assembly (FESA). The influence of chemically patterned substrate (i.e., hydrophobic stripes on a hydrophilic substrate) on the formation of colloidal microchannels was explored. In addition, such colloidal microchannels with tunable center-to-center distance between the adjacent cracks, λ_(c-c) was exploited as template for aligning inorganic nanoparticles. Importantly, theoretical study of the formation mechanism of parallel stripes of solutes by FESA was conducted. The relationship between the characteristic spacing of adjacent stripes λ_(c-c) and other experimental parameters such as the stripe width, the stop time and the moving speed of lower substrate were scrutinized. Such theoretical modeling would provide guidance for the precise design and crafting of ordered structures composed of nanomaterials by FESA in the future study. Interestingly, during the preparation of Au nanorods, the formation of ultrathin gold nanowires were unexpectedly observed. Based on conventional synthetic route to Au nanorods using CTAB as soft-templates, we discovered that the addition of a small amount of hydrophobic solvent (e.g., toluene or chloroform) to the Au growth solution entailed the formation of ultrathin Au nanowire, rather than Au nanorods. The growth mechanism of such intriguing water-soluble ultrathin Au nanowires, differed from those formed by using oleylamine (i.e., non-water-soluble Au nanowires), was explored. In general, the ability to craft ordered structures comprising nanomaterials by FESA and CESA provides new opportunities for organizing nanomaterials for use in electronics, optics, optoelectronics, sensors, nanotechnology and biotechnology.
47

Assembly sequencing through graph reasoning : graph grammar rules for assembly planning

Manion, Charles Austin 25 March 2014 (has links)
Assembly planning is difficult and tedious, but is necessary for complex products. This thesis presents a novel approach to automating assembly planning utilizing graph grammars. Computational geometric reasoning is used to produce a label rich graph from a CAD model. This graph is then modified by graph grammar rules to produce candidate assembly sequences which are run in conjunction with a tree search algorithm. An evaluation system then evaluates partial assembly sequences, which are used by the tree- search to find near-optimal assembly sequences. / text
48

A study of habit facilitation and interference in learning assembly operations

O'Connor, Robert Bernard 08 1900 (has links)
No description available.
49

A cost trade-off approach to paralleling options in assembly line balancing

Dunia, Jaime Jamil 08 1900 (has links)
No description available.
50

Electrochemical Characterization of Platinum based anode catalysts for Polymer Exchange Membrane Fuel Cell.

Gcilitshana, Oko Unathi. January 2008 (has links)
<p>In this study, the main objective was to investigate the tolerance of platinum based binary anode catalysts for CO poisoning from 10ppm up to1000ppm and to identify the<br /> best anode catalysts for PEMFCs that tolerates the CO fed with reformed hydrogen.</p>

Page generated in 0.0449 seconds