Performance of a polymer light-emitting diode with enhanced charge carrier mobility

The device characteristics of a polymer light-emitting diode (PLED) based on a poly(p-phenylene vinylene) (PPV) derivative with an enhanced charge carrier mobility have been investigated. Improvement of the mobility, which has been obtained by a decrease of the energetic disorder in the polymer, is expected to increase the power efficiency of a PLED. However, it is demonstrated that an increased mobility leads to a decrease as well as to a slower rise of the quantum efficiency with voltage. This performance reduction is explained in terms of an increased quenching of the electroluminescence (EL) at the cathode.

On-chip separation and sensing systems for hydrodynamic chromatography

The feasibility of on-chip analytical separations using planar hydrodynamic chromatography (HDC) in Pyrex-silicon and fused silica chips has been demonstrated. In order to sketch the analytical separations area in which the HDC chip has to operate, an introduction was given of important macro-scale separation techniques and their microfabricated counterparts. Furthermore, an impression of separation techniques that are enabled specifically by microtechnology was presented. One of these techniques is on-chip planar hydrodynamic chromatography. Other techniques are mainly aimed at DNA analysis using differences in transport of DNA through various constraining (microfabricated) geometries. Two types of HDC chips have been fabricated. The first type employs a Pyrex top wafer and a silicon bottom wafer, while the second type is fabricated using fused silica for both top and bottom wafers. Separation and injection channels were defined in the bottom wafer, whereas the top wafer provided through-holes for external connections. One particular part of the fabrication technology, fusion bonding of Pyrex to silicon and of fused silica to fused silica, was thoroughly investigated both theoretically and experimentally. Bonding of Pyrex to silicon induces thermal stresses, which cause a slight deformation of the channel geometry. This deforms the sample zones thus decreasing the device performance. The thermal deformation was reduced by using fused silica. This has the additional advantage of a good transparency down to the deep-UV. Fabrication of the fused silica HDC chip required additional processing development, especially aimed at Reactive Ion Etching of deeper structures. The HDC chip designs were made using a combination of computational fluid dynamics and analytical expressions. Investigation of the chromatographic and technological constraints lead to a first Pyrex-silicon HDC chip design, incorporating a 1 μm deep and 0.5 or 1 mm wide separation channel and a deeper (20 μm) integrated injection configuration. Apart from an enhanced injection structure, the fused silica HDC chip also incorporated an optical detection cell, located directly after the separation channel. This detection cell had roughly the same cross-sectional area as the separation channel, but was 30 μm deep, thereby giving a 30-fold increase in the path length for external optical detection. All characterization steps were performed optically. For the Pyrex-silicon chip fluorescence imaging directly inside the 1 μm deep separation channel was used. The correct operation of the injection structure for the Pyrex-silicon and fused silica chips was demonstrated by visualization of the concentration distribution of a fluorescent dye. Subsequently, the separation capabilities in both chip types were demonstrated by separation of various polystyrene nanoparticles. In the fused silica chip detection of the particles was performed using UV absorption detection through the integrated optical detection cell. In the Pyrex-silicon chip separation of large biomolecules was shown as well. Additionally, it was shown that relatively small molecules could be separated, not by using the hydrodynamic separation effect, but by interaction with the relatively large channel wall surface area (adsorption chromatography). The retention data for the particle separations showed that the influence of electrostatic and hydrodynamic particle-wall interactions on the particle retention behavior is not yet well understood and needs further research. The particle separations, detected using UV absorption through the detection cell, enabled a quantitative estimate of the peak broadening. Plate numbers ranging from 10.000 for small analytes to more than 100.000 for large fluorescent and non-fluorescent polystyrene nanoparticles were obtained. Qualitative comparison of (fluorescent) zone shapes showed that thermal deformation of the Pyrex-silicon separation channel, resulting in a higher dispersion, is less pronounced in narrower channels. Narrower channels however exhibit a relatively large influence of the side-walls on the total peak broadening, which leads to smaller plate numbers. Improvement of the separation resolution must therefore be aimed at reduction of the side-wall induced dispersion and of the thermal deformation. This could be realized by using wider channels, defined in fused silica. For integration with the Pyrex-silicon HDC chip a prototype stand-alone viscosity detector was developed using a technologically compatible fabrication process. The functionality of the differential detector was demonstrated by measuring the viscosity change caused by an ethanol plug in deionized water. A viscosity sensing resolution of Δηsp = 3*10-3 was estimated from those measurements. For the HDC chip a resolution of 10-4 is required. The difference can be explained by the extremely low volume flows and sample volumes required in on-chip HDC. Upscaling of the viscosity detector for higher volume flows theoretically improves the detection limits. Upscaling could thus create a functional viscosity detector with sample volumes that are much smaller than required for commercial viscodetectors. This could enable application of the detector for miniaturized (not necessarily micromachined) liquid chromatography systems for polymer analysis

Making the music dance : dance connotations in Norwegian fiddling

Publisher PD

FCC Regulation of the Telecommunications Press

Storstäderna växer och folk vill bo allt mer centralt, men det finns inte mycket yta att bygga på ifall man inte vill offra naturområden. En lösning är att bygga på höjden, det vill säga öka antalet våningar. Det är vad denna uppsats handlar om och hur bostads- och hyresrättsföreningar kan dra nytta av detta genom att öka sin ekonomiska vinning, samtidigt som de gör samhället en tjänst och är med och mättar behovet. Det denna uppsats kommer att behandla är hur ekonomin i olika föreningar ändras i samband med takpåbyggnad med en eller flera våningar och hur detta skiljer sig utifrån olika tekniska lösningar. Syftet är att utifrån detta skapa en uppsats som kan gagna framtida fastigheter som överväger att göra en sådan ombyggnation. De metoder vi kommer använda är granskning av dokumentation och handlingar från olika föreningar som har genomgått en takpåbyggnad av en eller flera våningar. Dessa kommer att användas för att göra uträkningar och egna analyser. Även intervjuer med styrelsemedlemmar i bostadsrättsföreningarna och företag som utför takombyggnationer förekommer. Tekniska och juridiska krav behandlas även om vad som generellt gäller för en takpåbyggnad. I slutet så sker en analys av objekten, där man får se resultatet av det som undersökts. Avslutningsvis så kommer slutsatsen som ger oss svaret att en bostadsrättsförenings ekonomi med största sannolikhet gynnas av en ombyggnation av detta slag om möjligheten finns. De variationer som förekom var oftast lägesrelaterade och man kan se en tydlig korrelation mellan vinsten och ju mer centralt man hamnade. Slutsatsen är alltså i sin enkelhet att om möjligheten finns så är en våningstakpåbyggnad med stor sannolikhet ett lönsamt alternativ.The big cities are growing and people want to live ever more centrally, but there is not much space to build on if you do not want to sacrifice the natural areas. One solution is to build higher, namely increasing the number of floors. That's what this essay is about and how housing and tenancy associations can take advantage of this by increasing their financial gain, while they’re doing the community a service and is with and saturates need. There we will examine is how the economies of various compounds change with a storey extension with one or more floors and how this differs from different technical solutions. The aim is that by this create an essay that will benefit future properties that are considering doing such conversions. The methods we will use is the examination of records and documents of various cases that have undergone a storey extension of one or more floors. These will be used to make the calculations and their own analyzes. Interviews with board members of housing cooperatives and companies that perform storey extensions occur. Technical and legal claims are pending, although generally applicable for a storey extension. In the end this happens, an analysis of the items, where you see the results of what has been investigated. Finally it will conclude that gives us the answer to a housing association economy most likely benefits from a reconstruction of this kind if the possibility exists. The variations that occurred were usually locational and one can see a clear correlation between the gain and the more centrally it ended. The conclusion is thus in its simplicity that if there is a possibility to do a storey extension, then it probably is a viable alternative

IMMORALITY IN CICERO. I. Hammar Making Enemies. The Logic of Immorality in Ciceronian Oratory. Pp. 381. Lund: Lund University, 2013. Paper. ISBN: 978-91-7473-613-7.

No abstract available

Electron capture in GaAs quantum wells via electron-electron and optic phonon scattering

Electron capture times in a separate confinement quantum well (QW) structure with finite electron density are calculated for electron-electron (e-e) and electron-polar optic phonon (e-pop) scattering. We find that the capture time oscillates as function of the QW width for both processes with the same period, but with very different amplitudes. For an electron density of 10^11 cm^-2 the e-e capture time is 10-1000 times larger than the e-pop capture time except for QW widths near the resonance minima, where it is only 2-3 times larger. With increasing electron density the e-e capture time decreases and near the resonance becomes smaller than the e-pop capture time. Our e-e capture time values are two-to-three orders of magnitude larger than previous results of Blom et al. [Appl. Phys. Lett. 62, 1490 (1993)]. The role of the e-e capture in QW lasers is therefore readdressed.Comment: 5 pages, standard LaTeX file + 5 PostScript figures (tarred, compressed and uuencoded) or by request from [email protected], accepted to Appl. Phys. Let

Diverse Learners and Teacher Education: A Sociocultural Approach

The “achievement gap” is a current issue in teacher education and PK-12 schools. Why do schools seem to privilege white, middle to upper class students and oppress others? School districts are under pressure to eliminate this gap, and for years, teacher educators have attempted to address these questions—but often using a deficit way of looking at children and families that exacerbates the problem. At the same time, colleges and universities are currently grappling with shifting needs and desires of students who have expectations for time and technology that do not match traditional delivery models of higher education. Based on these concerns, we conducted a broad literature review, surveys, and archival research regarding diverse learners and teacher education in Oregon. The purpose of this research was to examine practices in PK-12 teaching and teacher education regarding diverse learners, to determine the needs of diverse learners in Oregon and how these needs are or are not being met by various teacher education programs, and to examine teacher education programs in light of the 21st century college student. As a result of the literature review and data collection, we redesigned Multicultural Education to include multiliteracies, service-learning, more time and attention to specific strategies for working with diverse learners, and a comprehensive assessment system