Surface properties of polymers and competition adsorption of toluene and heptane on silica were studied using IR-visible sum frequency generation (SFG) vibrational spectroscopy. SFG is intrinsically surface sensitive because the second-order optical process is forbidden in media with inversion symmetry, such as bulk polymers and liquids. This nonlinear optical technique provides surface vibrational spectra under ambient conditions without the need of an ultra-high vacuum environment. Polymer surface properties, including surface relaxation temperature of poly(methyl methacrylate) (PMMA) and surface electronic states of poly[2-methoxy, 5-ethyl (2’-hexyloxy) para phenylenevinylene] (MEH-PPV), were investigated. It was found that there are significant differences between the surface and bulk properties for these polymers. For PMMA, a new surface structure relaxation was identified at 67°C, which does not match any known structure relaxation temperatures for bulk PMMA and is 40°C below the bulk glass transition temperature. For MEH-PPV, SFG electronic spectra, which were obtained by scanning the frequencies of incident visible and JR beams, indicated that the electronic states at the polymer/solid and air/polymer interfaces are red-shifted with respect to that of the bulk. Finally, SFG was employed to study the competition adsorption of toluene and heptane on silica surfaces. Experimental data showed that heptane adsorbed favorably compared to toluene. Using a Langmuir adsorption isotherm, the changes of Gibbs free energy for the adsorption processes were calculated to be —12.1 ± 1.8 (kJ/mol) for toluene and —16.5 ± 2.3 (kJ/mol) for heptane.

The application of adaptive beamforming to biomedical ultrasound imaging has been an active research area in recent years. Adaptive beamforming techniques have the capability of achieving excellent resolution and sidelobe suppression, thus improving the quality of the ultrasound images. This quality improvement, however, comes at a high computational cost. The work presented in this thesis aims to answer the following basic question: Can we reduce the computational complexity of adaptive beamforming without a significant degradation of the image quality? Our objective is to explore a combination of low-complexity non-adaptive beamforming, such as the conventional Delay-and-Sum (DAS) method, with high-complexity adaptive beamforming, such as the standard Minimum-Variance Distortionless Response (MVDR) method implemented using the Generalized Sidelobe Canceller (GSC). Such a combination should have the lower computational complexity than adaptive beamforming, but it should also offer the image quality comparable to that obtained using adaptive beamforming. In addition to the adaptive GSC-based MVDR beamforming method, we also investigate the performance of the so-called Adaptive Single Snapshot Beamformer (ASSB), which is relatively unexplored in the ultrasound imaging literature. The main idea behind our approach to combining a non-adaptive beamformer with an adaptive one is based on the use of the data-dependent variable known as the coherence factor. The resulting hybrid beamforming method can be summarized as follows: For each input snapshot to be beamformed, calculate the corresponding coherence factor; if the coherence factor is below a certain threshold, use non-adaptive DAS beamforming, otherwise use adaptive (GSC-based or ASSB-based) beamforming. We have applied this simple switching scheme to the simulated B-mode ultrasound images of the 12-point and point-scatterer-cyst phantoms that are commonly used in the ultrasound imaging literature to evaluate the image quality. Our simulation results show that, in comparison to optimal high-complexity always-adaptive beamforming, our hybrid beamformer can yield significant computational savings that range from 59% to 99%, while maintaining the image quality (measured in terms of resolution and contrast) within a 5% degradation margin. / Graduate

Surface properties of polymers and competition adsorption of toluene and heptane on silica were studied using IR-visible sum frequency generation (SFG) vibrational spectroscopy. SFG is intrinsically surface sensitive because the second-order optical process is forbidden in media with inversion symmetry, such as bulk polymers and liquids. This nonlinear optical technique provides surface vibrational spectra under ambient conditions without the need of an ultra-high vacuum environment. Polymer surface properties, including surface relaxation temperature of poly(methyl methacrylate) (PMMA) and surface electronic states of poly[2-methoxy, 5-ethyl (2’-hexyloxy) para phenylenevinylene] (MEH-PPV), were investigated. It was found that there are significant differences between the surface and bulk properties for these polymers. For PMMA, a new surface structure relaxation was identified at 67°C, which does not match any known structure relaxation temperatures for bulk PMMA and is 40°C below the bulk glass transition temperature. For MEH-PPV, SFG electronic spectra, which were obtained by scanning the frequencies of incident visible and JR beams, indicated that the electronic states at the polymer/solid and air/polymer interfaces are red-shifted with respect to that of the bulk. Finally, SFG was employed to study the competition adsorption of toluene and heptane on silica surfaces. Experimental data showed that heptane adsorbed favorably compared to toluene. Using a Langmuir adsorption isotherm, the changes of Gibbs free energy for the adsorption processes were calculated to be —12.1 ± 1.8 (kJ/mol) for toluene and —16.5 ± 2.3 (kJ/mol) for heptane. / Science, Faculty of / Chemistry, Department of / Graduate

Syftet med denna studie var att undersöka speciallärares syn på matematiksvårigheter i grundskolans tidiga år. Vi ville söka svar på vilka svårigheter speciallärare med utbildningen specialisering mot matematikutveckling ansåg vara mest förekommande inom matematikämnet. Studien syftade även till att ta reda på vilka arbetssätt de menade vara mest effektiva i arbetet med elever i matematiksvårigheter, samt vilka orsaker de ansåg kunna ligga bakom dessa svårigheter. Studien grundades på en semistrukturerad metod, där kvalitativa intervjuer användes till datainsamling. I studien har fyra speciallärare intervjuats, alla från olika skolor och län, men med samma utbildning. Resultatet visade att speciallärarna ansåg att de mest förkommenade matematiksvårigheterna fanns inom området taluppfattning. Speciallärarna påpekade även att det inte fanns en metod som fungerar på alla utan det berodde på elev och situation. Under intervjuerna fokuserades även på olika begrepp som varit väsentliga för denna studie. En fråga var hur speciallärarna definierar begreppet SUM, vilket gav lite olika svar. Ett par av speciallärarna ansåg att SUM kunde innefatta både elever i matematiksvårigheter, men även elever med fallenhet för matematik. De andra svarade att SUM är elever i svårigheter, vilket även mycket av forskningen pekar på. Ett annat begrepp som diskuterades var dyskalkyli. Detta begrepp har inte helt definierats av tidigare forskning, och innebörden har heller inte bekräftats. Samtliga speciallärare poängterade att de inte använde sig av begreppet eftersom de inte var säkra på vad det innebar, utan använde sig istället av ordet matematiksvårigheter. Matematiksvårigheter är därför även det begrepp vi använt oss av genomgående i studien.

No description available.

In this thesis we determine the submodule structure of a number of Weyl modules for algebraic groups with root systems B2 and G2. We use the Jantzen sum formula to find the composition factors of Weyl modules and go on to use homomorphisms between Weyl modules, given by H.H. Andersen, and the comparison of two filtrations of tensor products of Weyl modules to establish submodule structure. A computer program in the Prolog language is given which calculates the Jantzen sum formula. In addition we find one 2-dimensional Ext group for simple modules for type G2 in characteristic greater than or equal to 7.

Vibrational sum frequency spectroscopy (VSFS) is a nonlinear optical process. The sum frequency signal is proportional to the square of second order nonlinear susceptibility, which is proportional to the average of polarizabilities of molecules, which is related to molecular orientation. Since the polarizabilities of molecules in bulk phase will be canceled out, a sum frequency signal can only be generated from interfaces where the inversion symmetry is broken. Because of its interfacial specificity, VSFS has been applied to study many interfacial phenomena. In this dissertation we investigated various biological interfaces with VSFS. Fibrinogen adsorption was studied at the protein/solid interface in combination with atomic force microscopy (AFM), immunoassay, and VSFS. Astonishing changes in the interfacial water orientation accompanied by the pH changes provided fibrinogen’s adsorption mechanism up to the amino acid level. Enzymatic fragmentation of fibrinogen revealed that the adsorption property of fibrinogen was mainly from the alpha C fragments of the protein. Mimicking of the fibrinogen binding site with polypeptides was successfully performed and showed very similar properties of fibrinogen adsorption. Protein stability is sensitive to the salts in solutions. The ability of ions to stabilize protein was ordered by Hofmeister in 1888 and the order is SO4 2- ≅ HPO4 2- > F- > Cl- > Br- > NO3 - > I- (≅ ClO4 -) > SCN-. Even though the phenomenon was observed in various biological systems, the origin of those ionic effects is still not well understood. We studied ion effects on alkyl chain ordering and interfacial water structure for octadecylamine, dimethyldidodecylammonium bromide, and dilauroylphosphotidyl choline monolayers. Because of its ability to probe a hydrophobic moiety and interfacial water at the same time, VSFS provided further information to understand the Hofmeister series. We found that the Hofmeister effect is a combinatorial effect of screening effects, ion binding, and dispersion forces.

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Undervisas alla elever inom ramen för den ordinarie undervisningen? Eller är det kanske så att den allmänna uppfattningen gällande synen på de elever som är i behov av extra stöd är att de är ovilliga att lära? Hur uppfylls skolans samhällsuppdrag? Varför väljs just detta upplägg? Detta är alla starka frågor som kanske inte alltid är lämpliga att uttrycka just på detta vis men likväl otroligt viktiga att lyfta för att som framtida aktiv lärare kunna leva upp till mitt pedagogiska uppdrag utifrån gällande styrdokument. Jag har därför genom denna fallstudie, ur ett specialpedagogiskt perspektiv, undersökt vilket arbete som utförs av några lärare i grundskolans senare år för att kunna inkludera elever med speciella utbildningsbehov i matematik i den ordinarie undervisningsgruppen. Genom att använda mig utav deltagande observationer med påföljande semistrukturerade lärarintervjuer i en kvalitativ fallstudie kom jag fram till att ett inkluderande arbete måste ses ur flera dimensioner där individens personliga utveckling till aktivt deltagande samhällsmedborgare bör vara främsta prioritet. Resultatet visar att en inkluderande undervisningsmiljö inte nödvändigtvis är beroende av varje individs deltagande i den ordinarie undervisningsgruppen utan att det gemensamma arbetsklimatet på hela skolan i vidare mening är det som avgör om en inkluderande undervisning uppnåtts och att man av denna anledning bör ställa sig frågan om synen på en inkluderande undervisning behöver omvärderas för att kunna uppnå syftet med densamma.

No description available.