| 1. |
- Abgrall, N., et al.
(författare)
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The large enriched germanium experiment for neutrinoless double beta decay (LEGEND)
- 2017
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Ingår i: AIP Conference Proceedings. - : Author(s). - 1551-7616 .- 0094-243X. ; 1894
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Konferensbidrag (refereegranskat)abstract
- The observation of neutrinoless double-beta decay (0νββ) would show that lepton number is violated, reveal that neu-trinos are Majorana particles, and provide information on neutrino mass. A discovery-capable experiment covering the inverted ordering region, with effective Majorana neutrino masses of 15 - 50 meV, will require a tonne-scale experiment with excellent energy resolution and extremely low backgrounds, at the level of ∼0.1 count /(FWHM·t·yr) in the region of the signal. The current generation 76Ge experiments GERDA and the Majorana Demonstrator, utilizing high purity Germanium detectors with an intrinsic energy resolution of 0.12%, have achieved the lowest backgrounds by over an order of magnitude in the 0νββ signal region of all 0νββ experiments. Building on this success, the LEGEND collaboration has been formed to pursue a tonne-scale 76Ge experiment. The collaboration aims to develop a phased 0νββ experimental program with discovery potential at a half-life approaching or at 1028 years, using existing resources as appropriate to expedite physics results.
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| 2. |
- Cometto, O., et al.
(författare)
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Control of Nanoplane Orientation in voBN for High Thermal Anisotropy in a Dielectric Thin Film: A New Solution for Thermal Hotspot Mitigation in Electronics
- 2017
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Ingår i: ACS Applied Materials & Interfaces. - : American Chemical Society (ACS). - 1944-8252 .- 1944-8244. ; 9:8, s. 7456-7464
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Tidskriftsartikel (refereegranskat)abstract
- High anisotropic thermal materials, which allow heat to dissipate in a preferential direction, are of interest as a prospective material for electronics as an effective thermal management solution for hot spots. However, due to their preferential heat propagation in the in-plane direction, the heat spreads laterally instead of vertically. This limitation makes these materials ineffective as the density of hot spots increases. Here, we produce a new dielectric thin film material at room temperature, named vertically ordered nanocrystalline h-BN (voBN). It is produced such that its preferential thermally conductive direction is aligned in the vertical axis, which facilitates direct thermal extraction, thereby addressing the increasing challenge of thermal crosstalk. The uniqueness of voBN comes from its h-BN nanocrystals where all their basal planes are aligned in the direction normal to the substrate plane. Using the 3 omega method, we show that voBN exhibits high anisotropic thermal conductivity (TC) with a 16-fold difference between through-film TC and in-plane TC (respectively 4.26 and 0.26 W.m(-1).K-1). Molecular dynamics simulations also concurred with the experimental data, showing that the origin of this anisotropic behavior is due to the nature of voBN's plane ordering. While the consistent vertical ordering provides an uninterrupted and preferred propagation path for phonons in the through-film direction, discontinuity in the lateral direction leads to a reduced in-plane TC. In addition, we also use COMSOL to simulate how the dielectric and thermal properties of voBN enable an increase in hot spot density up to 295% compared with SiO2, without any temperature increase.
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| 3. |
- Jing, Lin, et al.
(författare)
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Thermal Conductivity Enhancement of Coaxial Carbon@Boron Nitride Nanotube Arrays
- 2017
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Ingår i: ACS Applied Materials & Interfaces. - : American Chemical Society (ACS). - 1944-8252 .- 1944-8244. ; 9:17, s. 14555-14560
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate the thermal conductivity enhancement of the vertically aligned carbon nanotube (CNT) arrays (from ?15.5 to 29.5 W/mK, ?90% increase) by encapsulating outer boron nitride nanotube (BNNT, 0.97 nm-thick with ?3-4 walls). The heat transfer enhancement mechanism of the coaxial C@BNNT was further revealed by molecular dynamics simulations. Because of their highly coherent lattice structures, the outer BNNT serves as additional heat conducting path without impairing the thermal conductance of inner CNT. This work provides deep insights into tailoring the heat transfer of arbitrary CNT arrays and will enable their broader applications as thermal interface material.
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| 4. |
- Zhang, Q., et al.
(författare)
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Effect of sintering method on properties of nanosilver paste
- 2017
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Ingår i: 2017 IMAPS Nordic Conference on Microelectronics Packaging, NordPac 2017, Goteborg, Sweden, 18-20 June 2017. ; , s. 186-189
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Konferensbidrag (refereegranskat)abstract
- Nanoscale silver paste has a good application prospect in heat dissipation of high-power chips due to the characteristics of low temperature sintering and high temperature service. The properties of the nanosilver paste including thermal conductivity, electrical conductivity, and shear strength are affected greatly by the sintering process. The influence of different sintering methods on the performance of the nanosilver paste was studied in this article. The nanosilver paste with 80.5 wt% nano-scale silver particles, 1.5 wt% submicron-scale SiC particles with Ag coating, 0.9 wt% dispersion agent, 10 wt% organic carrier and 7.1 wt% diluting agent was sintered at 260°C for 30 min with three different methods, heating table sintering, heating furnace sintering, and mixed sintering. The samples obtained by mixed sintering process have higher thermal conductivity than the ones obtained by heating furnace sintering method and heating table sintering method. The effect of sintering methods on shear strength of nanosilver paste was also investigated subsequently. Shear testing equipment was used to measure the shear strength of the samples gained by heating table sintering, heating furnace sintering, and air dry oven sintering. The maximum shear strength was obtained for the samples by heating table sintering method. The shear strength of samples by air dry oven sintering method was the minimum one.
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| 5. |
- Bistarelli, Silvia, et al.
(författare)
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Evaluating CNT-Based Interconnects : A Nummerical Tool to Characterize Hybrid CNT-Copper Interconnects
- 2017
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Ingår i: IEEE Microwave Magazine. - 1527-3342 .- 1557-9581. ; 18:4, s. 124-129
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Tidskriftsartikel (refereegranskat)abstract
- Nanotechnologies offer a vast number of applications due to the unique features of nanostructured materials [1]. In the electronics field, this new technology could open innovative ways to go beyond Moore's law [2], but progress in manufacturing technology still limits the wide dispersion of nanotechnology-based circuits. The bridge between nanoscience and realized devices can be achieved by modeling the multiphysics phenomena at the nanoscale, which will aid in the development of the technology.
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| 6. |
- Casa, Marcello, et al.
(författare)
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Silver decorated graphene-polyvinyl alcohol hybrid hydrogel as catalyst for benzonitrile conversion
- 2017
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Ingår i: Advanced Science Letters. - : American Scientific Publishers. - 1936-7317 .- 1936-6612. ; 23:6, s. 5980-5983
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Tidskriftsartikel (refereegranskat)abstract
- In this work, we have synthetized a reduced graphene oxide functionalized with silver nanoparticles (G/Ag) by a method developed in our previous study and incorporated it in a hydrogel based on polyvinyl alcohol (PVA) as gelator through a freezing/thawing method. The hydrogel has been tested to catalyze the reduction at room temperature of nitrile group of benzonitrile in water by using glucose as a natural and mild reducing agent.
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| 7. |
- Chen, S., et al.
(författare)
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An overview of carbon nanotubes based interconnects for microelectronic packaging
- 2017
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Ingår i: 2017 IMAPS Nordic Conference on Microelectronics Packaging, NordPac 2017, Goteborg, Sweden, 18-20 June 2017. - 9781538630556 ; , s. 113-119
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Konferensbidrag (refereegranskat)abstract
- Owing to the great demand in more functions and miniaturization in microelectronic packaging, the dimensions of interconnects has decreased extremely, which has resulted in electrical, thermal, and mechanical reliability issues. To address these issues, carbon nanotube (CNT) has been selected as a promising alternative material for the interconnects in packaging due to its large current density, high thermal conductivity, great flexibility, and low coefficient of thermal expansion (CTE). In this paper, the development of CNTs based vertical interconnects was reviewed. However, the resistivity of CNTs based interconnects was much higher than that of copper interconnects. Thus, this review focused on the resistivity of CNTs-based interconnects in different fabrication process and pointed out what improves the resistivity. In the future, CNTs-Cu nanocomposite with unique properties could be the suitable material for bumps to reduce the resistivity of CNTs based bumps further.
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| 8. |
- Darmawan, C. C., et al.
(författare)
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Graphene-CNT hybrid material as potential thermal solution in electronics applications
- 2017
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Ingår i: 2017 IMAPS Nordic Conference on Microelectronics Packaging (NordPac). - 9781538630556 ; , s. 190-193
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Konferensbidrag (refereegranskat)abstract
- Graphene and CNT have great potential in electronics applications. This work explored the possibility of integrating 1D CNT and 2D graphene into a 3D covalently bonded structure, i.e. a graphene-CNT hybrid material for thermal management application. The graphene-CNT hybrid material was later investigated morphologically and thermally to observe its heat dissipation capability.
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| 9. |
- Grammatikos, Sotirios, 1985, et al.
(författare)
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Concrete setting and hardening monitoring using a novel graphene-based sensor
- 2017
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Ingår i: ICF 2017 - 14th International Conference on Fracture. ; 2, s. 1204-1205
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Konferensbidrag (refereegranskat)abstract
- This paper presents the procedure towards the development of a durable structural sensor based on graphene and other carbon fillers, for the monitoring of structural performance of concrete. The sensor captures electrical resistivity as a strength development and durability index during the whole service life of concrete. To date, performance monitoring systems usually fail in the long-run before the failure of the actual structure. The proposed sensor is embedded in the interrogated structure and ensures sustainable consolidation via appropriate physico-chemical adherence and mechanical interlocking. This allows for an efficient performance monitoring 'build-up' expected to surpass the service life of the parent concrete structure. The effects of different concentrations of graphene and other fillers on the electrical properties of concrete were studied. After an initial investigation to select the appropriate synthesis, the ability of the sensor to monitor the development of resistivity during setting and hardening was tested and the results are presented herein.
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| 10. |
- Gutierrez, Martí, 1993, et al.
(författare)
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Sintering of SiC enhanced copper paste for high power applications
- 2017
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Ingår i: 2017 IMAPS Nordic Conference on Microelectronics Packaging (NordPac). - 9781538630556 ; , s. 151-156
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Konferensbidrag (refereegranskat)abstract
- In this work a Cu paste consisting in both micro and nanoparticles was produced. The copper paste was produced with different additive weight percentages of Ag coated SiC and sintered for 30min at 500°C under 6,5MPa in N2 atmosphere. The thermal resistance and composition of the resulting joints was studied. XPS and EDX measurements show no significant oxidation of the Cu after sintering, which is attributed to the combination of reductive agents in the paste and the inert atmosphere. SEM images of cross sections show contacts with no voids between the SiC particles and the copper matrix. Thermal conductivity measurements with laser flash analysis (LFA) show that the additive increases the effective thermal conductivity to more than double of that of the pure copper paste at 2% additive weight percentage, but bigger amounts yield smaller improvements and presumably would eventually worsen it.
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