| 1. |
- Yakimova, Rositsa, et al.
(författare)
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Analysis of the Formation Conditions for Large Area Epitaxial Graphene on SiC Substrates
- 2010
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Ingår i: SILICON CARBIDE AND RELATED MATERIALS 2009, PTS 1 AND 2. - : Trans Tech Publications Inc.. ; 565, s. 645-648
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Konferensbidrag (refereegranskat)abstract
- We are aiming at understanding the graphene formation mechanism on different SiC polytypes (6H, 4H and 3C) and orientations with the ultimate goal to fabricate large area graphene (up to 2 inch) with controlled number of monolayers and spatial uniformity. To reach the objectives we are using high-temperature atmospheric pressure sublimation process in an inductively heated furnace. The epitaxial graphene is characterized by ARPES, LEEM and Raman spectroscopy. Theoretical studies are employed to get better insight of graphene patterns and stability. Reproducible results of single layer graphene on the Si-face of 6H and 4H-SiC polytypes have been attained. It is demonstrated that thickness uniformity of graphene is very sensitive to the substrate miscut.
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| 2. |
- Amiryarahmadi, Nata, 1982, et al.
(författare)
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Time-domain model of a tapping machine
- 2011
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Ingår i: Proceedings - 6th Forum Acusticum 2011, Aalborg, 27 June - 1 July 2011. - 2221-3767. ; , s. 1713-1718
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Konferensbidrag (refereegranskat)abstract
- In the past few years the use of lightweight buildings made of prefabricated wooden elements has become more common. Ease of installation, high accuracy and lightness of such buildings has attracted builders and designers. Sweden, having a large coverage of renewable forests has an increasing interest in multi-storey wooden buildings. However noise and vibration in wooden buildings is an issue of concern especially low frequency impact sound due to footsteps. Impact sound insulation of floors can be measured based on ISO 140-7 using standardized tapping machine as excitation source. Experience has shown that in many cases the results obtained by this method do not correlate with annoyance experienced by inhabitants. On the other hand, the method presented in ISO 140-7 has usually shown to be relevant for the evaluation of impact sound transmission of concrete floors. Discovering the source of this contradiction requires deeper understanding of the impact process. A first step would be to find the difference between contact forces of the tapping machine on different floor materials. One could then correlate it with inhabitants’ perceived annoyance. This paper is the first step of this investigation which is a part of a Swedish research project called AkuLite. In this work a time-dependent model based on Hertz’s contact law is presented for the tapping machine. The model is validated by measurements on a homogeneous concrete floor. Also the contribution of parameters such as damping and stiffness of floor material on the resulting impact force and vibrations is studied.
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| 3. |
- Gaponov, Yury, et al.
(författare)
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Some aspects of SR beamline alignment
- 2011
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - : Elsevier BV. - 0168-9002. ; 649:1, s. 231-233
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Konferensbidrag (refereegranskat)abstract
- Based on the Synchrotron Radiation (SR) beamline optical element-by-element alignment with analysis of the alignment results an optimized beamline alignment algorithm has been designed and developed. The alignment procedures have been designed and developed for the MAX-lab 1911-4 fixed energy beamline. It has been shown that the intermediate information received during the monochromator alignment stage can be used for the correction of both monochromator and mirror without the next stages of alignment of mirror, slits, sample holder, etc. Such an optimization of the beamline alignment procedures decreases the time necessary for the alignment and becomes useful and helpful in the case of any instability of the beamline optical elements, storage ring electron orbit or the wiggler insertion device. which could result in the instability of angular and positional parameters of the SR beam. A general purpose software package for manual, semi-automatic and automatic SR beamline alignment has been designed and developed using the developed algorithm. The TANGO control system is used as the middle-ware between the stand-alone beamline control applications BLTools, BPMonitor and the beamline equipment. (C) 2010 Elsevier B.V. All rights reserved.
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| 4. |
- Ghazzali, Mohamed I D M, 1974, et al.
(författare)
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Multi-component self-assembly of molecule based materials by coordination networks and weak intermolecular synthons
- 2011
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Ingår i: CrystEngComm. - : Royal Society of Chemistry (RSC). - 1466-8033. ; 13:19, s. 5813-5817
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Tidskriftsartikel (refereegranskat)abstract
- The coordination polymer [Fe(SCN)2(1,2-bis(4-pyridylmethylene)hydrazine)2]n [Fe(phenanthroline)3]2n(ClO4)2n·n1,2-bis(4-pyridylmethylene)hydrazine·4nH2O 1 was crystallised from a MeOH/MeCN solution and the structure consists of layered (4,4) 2D-nets with supramolecular ([Fe(phen)3]2bphz)4+ units in the pores and disordered water and perchlorate anions. The same supramolecular motif could be independently prepared as [Fe(phen)3]2·bphz(ClO4)4·xMeOH 2, and the [Ru(phenanthroline)3]2+ compound 3, isostructural to 1, was also prepared although a complete structure determination was prevented by low crystal quality. Compounds 1 and 3 are rare examples of how several large and different components can be assembled inside a 2D coordination network and provide a concept for multi-component self-assembly.
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| 5. |
- Ghazzali, Mohamed, et al.
(författare)
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Multi-component self-assembly of molecule based materials by coordination networks and weak intermolecular synthons
- 2011
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Ingår i: CrystEngComm. - : Royal Society of Chemistry (RSC). - 1466-8033. ; 13:19, s. 5813-5817
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Tidskriftsartikel (refereegranskat)abstract
- The coordination polymer [Fe(SCN)(2)(1,2-bis(4-pyridylmethylene)hydrazine)(2)](n) [Fe(phenanthroline)(3)](2n)(ClO4)(2n)center dot n1,2-bis(4-pyridylmethylene)hydrazine center dot 4nH(2)O 1 was crystallised from a MeOH/MeCN solution and the structure consists of layered (4,4) 2D-nets with supramolecular ([Fe(phen)(3)](2)bphz)(4+) units in the pores and disordered water and perchlorate anions. The same supramolecular motif could be independently prepared as [Fe(phen)(3)](2)center dot bphz(ClO4)(4)center dot xMeOH(2), and the [Ru(phenanthroline)(3)](2+) compound 3, isostructural to 1, was also prepared although a complete structure determination was prevented by low crystal quality. Compounds 1 and 3 are rare examples of how several large and different components can be assembled inside a 2D coordination network and provide a concept for multi-component self-assembly.
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| 6. |
- Gustafsson, Ola, et al.
(författare)
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Flat tube heat exchangers - Direct and indirect noise levels in heat pump applications
- 2014
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Ingår i: Applied Thermal Engineering. - : Elsevier BV. - 1359-4311. ; 66:1-2, s. 104-112
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Tidskriftsartikel (refereegranskat)abstract
- In the outdoor unit of an air-source heat pump the fan is a major noise source. The noise level from the fan is dependent on its state of operation: high air-flow and high pressure drop often result in higher noise levels. In addition, an evaporator that obstructs an air flow is a noise source in itself, something that may contribute to the total noise level. To be able to reduce the noise level, heat exchanger designs other than the common finned round tubes were investigated in this study. Three types of heat exchanger were evaluated to detect differences in noise level and air-side heat transfer performance at varying air flow. The measured sound power level from all the heat exchangers was low in comparison to the fan sound power level (direct effect). However, the heat exchanger design was shown to have an important influence on the sound power level from the fan (indirect effect). One of the heat exchangers with flat tubes was found to have the lowest sound power level, both direct and indirect, and also the highest heat transfer rate. This type of flat tube heat exchanger has the potential to reduce the overall noise level of a heat pump while maintaining heat transfer efficiency.
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| 7. |
- Gustafsson, Ola, et al.
(författare)
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NOISE LEVEL IN RELATION TO ENERGY PERFORMANCE OF AIR-TO-AIR HEAT PUMPS
- 2011
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Ingår i: 10th international heat pump conference.
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Konferensbidrag (refereegranskat)abstract
- With increased use of air source heat pumps, a possible barrier for further market growth and customer acceptance is their noise level. The disturbance is both an issue for the owner of the heat pump and the neighbors since both the indoor and the outdoor units radiate sound. The purpose of this study is to create an understanding of the noise generation of air-to-air heat pumps and relate this to their energy performance. This knowledge is then to be used in continued work when describing the total disturbance of a heat pump.Two heat pumps, both of inverter type and with different noise performance were selected for measurements. Energy performance, in the form of Coefficient of Performance (COP), was evaluated at different operating conditions. Measurements of the sound power level were performed on both the outdoor and the indoor units. Results show that the sound level from the indoor units is independent of the outdoor conditions. The noise from the outdoor units varies with different climates and the variation is particularly large at part load conditions.
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