| 1. |
- Zhang, X., et al.
(författare)
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Printed monopole antenna with extremely wide bandwidth on liquid crystal polymer substrates
- 2011
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Ingår i: Proceedings - 12th International Conference on Electronic Packaging Technology and High Density Packaging, ICEPT-HDP 2011, Shanghai, 8-11 August 2011. - 9781457717680 ; , s. 1157-1159
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Konferensbidrag (refereegranskat)abstract
- This letter presents a printed monopole antenna with extremely wide bandwidth on a liquid crystal polymer (LCP) substrate. It consists of a hollowed elliptical monopole, two trapeziform ground planes and a tapered co-planar waveguide (CPW) feeder. By using standard processing technology, this monopole antenna is fabricated on the direct metalized LCP film substrate. The fabricated antenna can achieve an extremely wide impedance bandwidth, a nearly omnidirectional radiation pattern and a compact size, which verifies that LCP materials are very suitable as substrates for commercial wireless applications.
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| 2. |
- Zhang, Yan, et al.
(författare)
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Numerical investigation on thermal properties of micro-pin-fin cooler
- 2011
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Ingår i: Journal of Shanghai University. - 1007-6417. ; 15:4, s. 273 - 278
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Tidskriftsartikel (refereegranskat)abstract
- Micro-pin-fin cooler mounted on the power chip enables the heat removal to meet modern microsystem requirement. Carbon nanotubes (CNTs) have been proven as a potential material for micro-coolers due to the superior thermal conductivity, good mechanical property and so forth, and there appear various applications of CNTs in the micro-cooler technology. In the present paper, an analysis of the thermal and hydraulic characteristics of the micro-pin-fin heat sink was conducted, where air was used as the cooling medium and an impinging jet was introduced to enhance the heat transfer. Three-dimension computational fluid dynamics (CFD) simulations were carried out for micro-pin-fin coolers with various parameters, including the pin-fin size and pattern as well as the jet velocity and nozzle diameter. The flow field and thermal properties of the micro-pin-fin heat sink were obtained, and the heat removal efficiency was evaluated.
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| 3. |
- Carlberg, Björn, 1983, et al.
(författare)
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Surface-Confined Synthesis of Silver Nanoparticle Composite Coating on Electrospun Polyimide Nanofibers
- 2011
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Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 7:21, s. 3057-3066
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Tidskriftsartikel (refereegranskat)abstract
- A methodology for fabricating hierarchical nanostructures by surface-confined synthesis of silver nanoparticles on electrospun polyimide nanofibers is reported. Through surface-confined imide cleavage at the dianhydride domain via immersion in an aqueous KOH solution, potassium polyamate coatings of accurately defined thickness are formed (at a rate of 25 nm h(-1)). By utilizing the ion-exchange capability of the polyamate resin, silver ions are introduced through immersion in an aqueous AgNO(3) solution. Subsequent reduction of the metal ion species leads to the formation of nanoparticles at the fiber surface. Two modes of reduction, chemical and thermal, are investigated in the report, each leading to distinct morphologies of the nanoparticle coatings. Via thermal reduction, a composite surface layer consisting of monodisperse silver nanoparticles (average diameter 5.2 nm) embedded in a re-imidized polyimide matrix is achieved. In the case of chemical reduction, the reduction process occurs preferentially at the surface of the fiber, leading to the formation of silver nanoparticles anchored at the surface, though not embedded, in a polyamic acid matrix. By regulating the modification depth, control of the particle density on the fiber surface is established. In both reduction approaches, the polyimide nanofiber core exhibits maintained integrity.
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| 4. |
- Du, W., et al.
(författare)
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Study into high temperature reliability of isotropic conductive adhesive
- 2011
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Ingår i: Proceedings - 12th International Conference on Electronic Packaging Technology and High Density Packaging, ICEPT-HDP 2011, Shanghai, 8-11 August 2011. - 9781457717680 ; , s. 1053-1055
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Konferensbidrag (refereegranskat)abstract
- With the rapid development of technologies for high density assembly and packaging in electronic industry, isotropic conductive adhesive (ICA) has been paid more and more attention as a potential substitute for solder, due to its advantages of low processing temperature, simple processing conditions and good manufacturability. However, studies into the reliability of ICA are not as abundant as those of solder. As a composite material, the failure feasibility of ICA not only depends not only on the variation in performance of different constituent parts, such as high temperature aging of the polymer, aging due to moisture absorption and oxidization of filler particles, but also on interface changes. Thus, the failure mechanism of ICA seems to be complicated and studies into the reliability of ICA are also necessary. Reliability in humidity and heat has been investigated in previous works, and in this paper high temperature reliability will be studied as a comparison. Some reliability tests and results will be given and some failure mechanisms discussed. Finally, we present some discussion about the further optimization of reliability for follow-up studies.
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| 5. |
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| 6. |
- Fan, Q., et al.
(författare)
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The effect of functionalized silver on properties of conductive adhesives
- 2011
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Ingår i: Proceedings - 12th International Conference on Electronic Packaging Technology and High Density Packaging, ICEPT-HDP 2011, Shanghai, 8-11 August 2011. - 9781457717680 ; , s. 423-425
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Konferensbidrag (refereegranskat)abstract
- This research used low molecular surface modifiers and observed that chemisorptions took place through the formation of a bond between silver surface and an adsorbed molecule, which improved the dispersion of silver flakes in the organic resin. Results of shear viscosity, bulk resistivity etc. showed that by using these low molecular organic functionalizers, isotropic conductive adhesives (ICAs) with lower shear viscosity and better electrical conductivity at high silver fillers content were obtained. Different processing methods and different matrixes were compared.
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| 7. |
- Fan, Q., et al.
(författare)
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The effect of functionalized silver on rheological and electrical properties of conductive adhesives
- 2011
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Ingår i: ECS Transactions. - : The Electrochemical Society. - 1938-5862 .- 1938-6737. - 9781607682356 ; 34:1, s. 811-816
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Konferensbidrag (refereegranskat)abstract
- This research used low molecular surface modifiers, and observed that chemisorptions took place through the formation of a bond between silver surface and an adsorbed molecule, which improved the dispersion of silver flakes in the organic resin. Several different functionalizers, such as thioglycolic acid, silane and di-acid, were used to functionalize the silver surface. Results of shear viscosity, bulk resistivity etc. showed that by using these low molecular organic functionalizers, isotropic conductive adhesives (ICAs) with lower shear viscosity and better electrical conductivity at high silver fillers content were obtained. The adipic acid had the greatest effect on the rheological and electrical property of ICAs, so its weight percentage in silver flakes was also optimized; ICAs displayed the maximum electrical conductivity when there was 0.5 wt% of silver flakes.
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| 8. |
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| 9. |
- Hu, Zhili, 1983, et al.
(författare)
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Influence of substrate on electrical conductivity of isotropic conductive adhesive
- 2011
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Ingår i: Proceedings of the IEEE International Symposium on Advanced Packaging Materials (APM), Xiamen, China, October 25-28, 2011. - 1550-5723. - 9781467301480 ; , s. 330 - 335
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Konferensbidrag (refereegranskat)abstract
- Isotropic conductive adhesive (ICA) is widely used with different kinds of substrates in electronics packaging applications. Therefore it is necessary to understand the influence of electrical conductivity of ICA from substrate. In this work, we investigated the electrical resistivity of ICA on quartz, PCB and glass substrate. The experimental data showed that the in-plane electrical conductivity of ICA on PCB is almost twice that of the glass substrate, while the conductivity of ICA on quartz is also significantly greater than that of glass, under the same curing temperature and with the same bond line thickness (BLT) of ICA. This paper later concludes that thermal conductive adhesive (TCA) on substrate with higher thermal expansion coefficient (CTE) is likely to give better performance. Finally, Finite Element Modeling (FEM) and analysis shows that this phenomenon could be universal to ICA and TCA.
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| 10. |
- Hu, Zhili, 1983, et al.
(författare)
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Molecular Gun Composed of Carbon Nanotube
- 2011
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Ingår i: Journal of Computational and Theoretical Nanoscience. - : American Scientific Publishers. - 1546-1955 .- 1546-1963. ; 8:9, s. 1716-1719
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Tidskriftsartikel (refereegranskat)abstract
- Using molecular simulation, this paper predicts that by bending one end of the outer carbon nanotube (CNT) of a double-wall CNT (DWCNT), the inner CNT could possibly be shot out with a speed of several 100 m/s, and a kinetic energy of several eV from either left or the right end of the outer CNT, depending on the length of inner CNT. Analysis in this paper suggests that the outer CNT is a supplier of the CNT bullet's kinetic energy and the bullet can be shot out only if the outer CNT buckles while the inner CNT does not. Noticeably, such molecular gun could be practical in experiment environment since the bending of a CNT could be obtained by applying external electrical field.
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