69 research outputs found
3D interconnect technology based on low temperature copper nanoparticle sintering
No full textWe explore a methodology for patterned copper nanoparticle paste for 3D interconnect applications in wafer to wafer (W2W) bonding. A novel fine pitch thermal compression bonding process (sintering) with coated copper nanoparticle paste was developed. Most of the particle size is between 10-30 nm. Lithographically defined stencil printing using photoresist and lift-off was used to apply and pattern the paste. Variations in sintering process parameters, such as: pressure, geometry and ambient atmosphere, were studied. Compared to Sn-Ag-Cu (SAC) microsolder bumps, we achieved better interconnect resistivity after sintering at 260 °C for 10 min, in a 700 mBar hydrogen forming gas (H2/N2) environment. The electrical resistivity was 7.84 ± 1.45 μΩ·cm, which is about 4.6 times that of bulk copper. In addition, metallic nanoparticle interconnect porosity can influence the electrical properties of the interconnect. Consequently, we investigated the porosity effect on conductivity using finite element simulation. A linear relationship between the equivalent conductivity and particle overlapping ratio was found.Accepted Author ManuscriptElectronic Components, Technology and MaterialsEKL Processin
On the crossing numbers of complete graphs
No full textI hereby declare that I am the sole author of this thesis. This is a true copy of the thesis, including any required final revisions, as accepted by my examiners. I understand that my thesis may be made electronically available to the public. ii In this thesis we prove two main results. The Triangle Conjecture asserts that the convex hull of any optimal rectilinear drawing of Kn must be a triangle (for n � 3). We prove that, for the larger class of pseudolinear drawings, the outer face must be a triangle. The other main result is the next step toward Guy’s Conjecture that the crossing number of Kn is
Productive facilitatory acts - An empirical study of Aalto ArtSpace co-design workshops
No full textCo-design has gain its popularity in engaging various stakeholders into the design process. Across the industry and academy, co-design workshops are widely used in the early phase of design. Due to the complex interaction nature of co-design workshops, it is challenging for the facilitators to get productive outcomes that are informative to the design project. Although numerous of co-design methods are offered, few attempts to elucidate how co-design practitioners shall facilitate co-design workshops productively.
In this thesis, the author sets out to de ne co-design workshops, facilitatory acts and attempts to identify productive facilitatory acts by analysing a serious of three co-design workshop. In addition, the author experiments with the Framing Analysis of Design Articulation (FADA) method (Ylirisku, 2013) in the process of analysing the workshop video records
Economic Transition and Industrial Restructuring in China: Structural Convergence or Divergence?
No full textChina has undergone substantial industrial restructuring since the economic transition. The triple process of marketisation, globalisation and decentralisation has had a significant influence on the changes in industrial structures in Chinese provinces. Using provincial–industrial level data for 1980–2003, this article finds that Chinese provinces are quite similar in their industrial structures. The interior provinces, however, have gradually specialised in resource-based industries, so their industrial structures deviate from the national structure, while the coastal provinces host fairly similar industries. Statistical analysis found that marketisation had enhanced the role of comparative advantage in natural resources, stimulating the divergence of industrial structures of provinces with different resource endowments while encouraging provinces with comparable endowments to develop similar industries. However, decentralisation generates economic fragmentation of domestic markets, fueling inter-provincial protectionism and rational imitation, and leading to the convergence of industrial structures among provinces. Globalisation has two effects. On the one hand, the globalised provinces have been converging in their industrial structures. On the other hand, the globalised provinces have rather different industrial structures from the underperforming provinces in exports and utilisation of FDI. This result implies that economic transition and its consequences are critical in understanding industrial restructuring in the transitional economies.
Green catalysis for selective CO oxidation in hydrogen for fuel cell
No full textPreferential oxidation of carbon monoxide in excess hydrogen (PROX) is one of the key processes for the production of clean hydrogen fuel for the polymer electrolyte membrane fuel cell (PEFC). Development of highly active and selective catalysts is among the most challenging works for decades. Platinum-based catalysts are regarded as the most promising candidates for this process. However, the activities of Pt catalysts seriously suffer from the strong poisonous adsorption by CO substrate at low reaction temperature. This article addresses the present approaches to improve the catalytic performance under the low temperature. The focus in this article is the finding over the Pt/mesoporous silica catalyst. The high activity and selectivity of this catalyst has been attributed to the surface silanols in mesoporous silica. The perspectives of Pt/mesoporous silica in the PROX reaction are also presented
Going green or going away: Environmental regulation, economic geography and firms’ strategies in China’s pollution-intensive industries
No full textThe high-growth, resource- and pollution-intensive industrialization model that China has pursued has caused severe environmental pollution and deterioration, particularly in a number of clusters in the coastal regions of East and Southeast China, where the Reform and Opening-up policies first started. The lack of uptake of environmental norms! values, deficit of regulatory enforcement of environmental policies, and insufficient institutional capacity have been compounding factors. As environmental standards were raised by China's central government, the enforcement of environmental regulation has been compromised more in inland China than in coastal regions, due to China's "decentralized governance structure" and regional disparity in terms of both economic development and environmental pollution. This paper therefore argues that rising environmental regulations, as well as firm characteristics, regional hub effect and political environment, have all been particularly important in forcing China's pollution-intensive enterprises to restructure their production, through innovation, upgrading, geographical relocation, outsourcing and plant closure, especially in China's coastal regions. It contributes to recent studies by developing a heuristic analytical framework that aims to be sensitive to the impacts of environmental regulation, political environment and regional hub effect over firm restructuring, but which does so by stressing these impacts are simultaneously inflected by the nature and attributes of firms. The empirical analysis suggests a roughly inverted "U"-shaped relationship between firm relocation tendency and firm size (or firm capability), resulting from complex interactions between political environment, regional hub effect and environmental regulation. (C) 2014 Elsevier Ltd. All rights [email protected]; [email protected]
Nontrivial Solution for the Fractional p-Laplacian Equations via Perturbation Methods
No full textWe study the existence of nontrivial solution of the following equation without compactness: (-Δ)pαu+up-2u=f(x,u), x∈RN, where N,p≥2, α∈(0,1), (-Δ)pα is the fractional p-Laplacian, and the subcritical p-superlinear term f∈C(RN×R) is 1-periodic in xi for i=1,2,…,N. Our main difficulty is that the weak limit of (PS) sequence is not always the weak solution of fractional p-Laplacian type equation. To overcome this difficulty, by adding coercive potential term and using mountain pass theorem, we get the weak solution uλ of perturbation equations. And we prove that uλ→u as λ→0. Finally, by using vanishing lemma and periodic condition, we get that u is a nontrivial solution of fractional p-Laplacian equation
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