Yes / Size Exclusion Chromatography is traditionally carried out in either aqueous or non-polar solvents. A system to present molar mass distributions of polymers using methanol as a mobile phase is presented. This is shown to be a suitable system for determining the molar mass distributions poly(N-isopropylacrylamide)s (PNIPAM); a polymer class that is often difficult to analyze by size exclusion chromatography. DOSY NMR was used to provide intrinsic viscosity data that was used in conjunction with a viscometric detector to provide absolute calibration. Then the utility of the system was shown by providing the absolute molar mass distributions of dispersed highly branched PNIPAM with biologically functional end groups. / Wellcome Trust

Challenges with integrating high-κ gate dielectric,retrograde Si1-xGexchannel and silicided contacts in future CMOStechnologies are investigated experimentally and theoreticallyin this thesis. ρMOSFETs with either Si or strained Si1-xGex surface-channel and different high-κgate dielectric are examined. Si1-xGex ρMOSFETs with an Al2O3/HfAlOx/Al2O3nano-laminate gate dielectric prepared by means ofAtomic Layer Deposition (ALD) exhibit a great-than-30% increasein current drive and peak transconductance compared toreference Si ρMOSFETs with the same gate dielectric. Apoor high-κ/Si interface leading to carrier mobilitydegradation has often been reported in the literature, but thisdoes not seem to be the case for our Si ρMOSFETs whoseeffective mobility coincides with the universal hole mobilitycurve for Si. For the Si1-xGexρMOSFETs, however, a high density ofinterface states giving riseto reduced carrier mobility isobserved. A method to extract the correct mobility in thepresence of high-density traps is presented. Coulomb scatteringfrom the charged traps or trapped charges at the interface isfound to play a dominant role in the observed mobilitydegradation in the Si1-xGexρMOSFETs. Studying contacts with metal silicides constitutes a majorpart of this thesis. With the conventional device fabrication,the Si1-xGexincorporated for channel applications inevitablyextends to the source-drain areas. Measurement and modelingshow that the presence of Ge in the source/drain areaspositively affects the contact resistivity in such a way thatit is decreased by an order of magnitude for the contact of TiWto p-type Si1-xGex/Si when the Ge content is increased from 0 to 30at. %. Modeling and extraction of contact resistivity are firstcarried out for the traditional TiSi2-Si contact but with an emphasis on the influenceof a Nb interlayer for the silicide formation. Atwo-dimensional numerical model is employed to account foreffects due to current crowding. For more advanced contacts toultra-shallow junctions, Ni-based metallization scheme is used.NiSi1-xGex is found to form on selectively grown p-typeSi1-xGexused as low-resistivity source/drain. Since theformed NiSi1-xGex with a specific resistivity of 20 mWcmreplaces a significant fraction of the shallow junction, athree-dimensional numerical model is employed in order to takethe complex interface geometry and morphology into account. Thelowest contact resistivity obtained for our NiSi1-xGex/p-type Si1-xGexcontacts is 5´10-8Ωcm2, which satisfies the requirement for the 45-nmtechnology node in 2010. When the Si1-xGexchannel is incorporated in a MOSFET, it usuallyforms a retrograde channel with an undoped surface region on amoderately doped substrate. Charge sheet models are used tostudy the effects of a Si retrograde channel on surfacepotential, drain current, intrinsic charges and intrinsiccapacitances. Closed-form solutions are found for an abruptretrograde channel and results implicative for circuitdesigners are obtained. The model can be extended to include aSi1-xGexretrograde channel. Although the analytical modeldeveloped in this thesis is one-dimensional for long-channeltransistors with the retrograde channel profile varying alongthe depth of the transistor, it should also be applicable forshort-channel transistors provided that the short channeleffects are perfectly controlled. Key Words:MOSFET, SiGe, high-k dielectric, metal gate,mobility, charge sheet model, retrograde channel structure,intrinsic charge, intrinsic capacitance, contactresistivity.

<p>Challenges with integrating high-κ gate dielectric,retrograde Si_1-xGe_xchannel and silicided contacts in future CMOStechnologies are investigated experimentally and theoreticallyin this thesis. ρMOSFETs with either Si or strained Si_1-xGex surface-channel and different high-κgate dielectric are examined. Si_1-xGex ρMOSFETs with an Al₂O₃/HfAlO_x/Al₂O₃nano-laminate gate dielectric prepared by means ofAtomic Layer Deposition (ALD) exhibit a great-than-30% increasein current drive and peak transconductance compared toreference Si ρMOSFETs with the same gate dielectric. Apoor high-κ/Si interface leading to carrier mobilitydegradation has often been reported in the literature, but thisdoes not seem to be the case for our Si ρMOSFETs whoseeffective mobility coincides with the universal hole mobilitycurve for Si. For the Si_1-xGe_xρMOSFETs, however, a high density ofinterface states giving riseto reduced carrier mobility isobserved. A method to extract the correct mobility in thepresence of high-density traps is presented. Coulomb scatteringfrom the charged traps or trapped charges at the interface isfound to play a dominant role in the observed mobilitydegradation in the Si_1-xGe_xρMOSFETs.</p><p>Studying contacts with metal silicides constitutes a majorpart of this thesis. With the conventional device fabrication,the Si_1-xGe_xincorporated for channel applications inevitablyextends to the source-drain areas. Measurement and modelingshow that the presence of Ge in the source/drain areaspositively affects the contact resistivity in such a way thatit is decreased by an order of magnitude for the contact of TiWto p-type Si_1-xGe_x/Si when the Ge content is increased from 0 to 30at. %. Modeling and extraction of contact resistivity are firstcarried out for the traditional TiSi₂-Si contact but with an emphasis on the influenceof a Nb interlayer for the silicide formation. Atwo-dimensional numerical model is employed to account foreffects due to current crowding. For more advanced contacts toultra-shallow junctions, Ni-based metallization scheme is used.NiSi_1-xGex is found to form on selectively grown p-typeSi_1-xGe_xused as low-resistivity source/drain. Since theformed NiSi1-xGex with a specific resistivity of 20 mWcmreplaces a significant fraction of the shallow junction, athree-dimensional numerical model is employed in order to takethe complex interface geometry and morphology into account. Thelowest contact resistivity obtained for our NiSi_1-xGe_x/p-type Si_1-xGe_xcontacts is 5´10^-8Ωcm², which satisfies the requirement for the 45-nmtechnology node in 2010.</p><p>When the Si_1-xGe_xchannel is incorporated in a MOSFET, it usuallyforms a retrograde channel with an undoped surface region on amoderately doped substrate. Charge sheet models are used tostudy the effects of a Si retrograde channel on surfacepotential, drain current, intrinsic charges and intrinsiccapacitances. Closed-form solutions are found for an abruptretrograde channel and results implicative for circuitdesigners are obtained. The model can be extended to include aSi_1-xGe_xretrograde channel. Although the analytical modeldeveloped in this thesis is one-dimensional for long-channeltransistors with the retrograde channel profile varying alongthe depth of the transistor, it should also be applicable forshort-channel transistors provided that the short channeleffects are perfectly controlled.</p><p><b>Key Words:</b>MOSFET, SiGe, high-k dielectric, metal gate,mobility, charge sheet model, retrograde channel structure,intrinsic charge, intrinsic capacitance, contactresistivity.</p>

Fewer students apply for and finish the teacher programs in Sweden, and manyteachers leave their job. Swedish schools are in need of more teachers, but theteaching profession is today portrayed as unattractive. This research aims toinvestigate what factors that motivate some students to become teachers and whatfactors that motivate some teachers, ESL teachers in first hand, to work as teachers,mainly in secondary schools in Malmoe. Three secondary teachers who teach ESL inMalmoe were interviewed and expressed their thoughts about the positive aspects ofthe teaching job, why they wanted to become and why they work as ESL teachers, andwhat goals they have in relation to their profession. The research showed that the ESLteachers teach because they feel passionate about the subject they teach and becausethey enjoy working with children and teenagers. They find the job fun and rewarding,and think that it is challenging, especially when working in a city like Malmoe. Itseems as teachers often put the pupils first and do not focus on external rewards, suchas salary. Teacher motivation has an impact on student motivation and it is thereforeimportant that teachers remain motivated within their profession.

Two mechanisms, intrinsic and factor-dependent, have evolved for accomplishing the termination of transcription in eubacteria. In this thesis, the first chapter is an introduction to the topic that presents what is known about the mechanisms of termination. The properties of the primary and secondary ‘players’- intrinsic terminators, Rho protein, rho-dependent terminators, RNA polymerse and Nus factors - are presented and the known mechanisms by which termination functions are discussed. In Chapter 2, a detailed analysis of intrinsic terminators – their differential distribution, similarity and divergence - has been penned. The database, compiled using the program GeSTer (Genome Scanner for Terminators), comprises ~2000 sequences and is one of the largest of its kind. Furthermore, analyzing the data from over 700 bacteria reveals how different species have fine-tuned intrinsic terminators to suit their cellular needs. Non-canonical intrinsic terminators emerge to be a significant fraction of the observed structures. The conserved structural features of identified intrinsic terminators are discussed and the relationship between the two modes of termination is assessed. Chapter 3 deals with the importance of transcription termination in regulating horizontally acquired DNA. The results show that genomic islands are scarce in intrinsic terminators and thus constitute most likely sites for Rho-dependent termination. Plausible reasons for why such a scenario has evolved are discussed and a generally applicable model is presented. Chapters 4 and 5 focus on Rho protein from Mycobacterium tuberculosis. In silico identification of M. tuberculosisgenes that rely on MtbRho-dependent termination is followed by experimental validation. The data show that Rho-dependent termination is the predominant mechanism in this species.MtbRho is a majorly expressed protein that governs termination of protein-coding and non-protein coding genes. Further, MtbRho can productively interact with RNA that has considerable secondary structure. Such interactions cause conformational changes in the enzyme. Given that MtbRho has to function with a GC-rich transcriptome, the altered properties could have evolved for optimal function. Taken together, the thesis extends our current understanding of both modes of termination. The importance of non-canonical intrinsic terminators in mycobacteria and other organisms is discussed. The unusual function of Rho and its predominant role in mycobacteria is elucidated. Finally, the inter-relationship between the two modes of termination is also discussed.

Det är av stort intresse för lärare och tränare att öka elevers inre motivation. Det finns flera studier av hur feedback påverkar den inre motivationen inom olika områden men motsvarande studie för ryttare saknas. Ridundervisning innefattar tre individer – tränare, ryttare och häst. Frågan är därför om ryttares inre motivation påverkas av tränarens feedback i samma utsträckning som i andra idrotter. I studien användes en inomgruppsdesign med 35 ryttare och tre betingelser; positiv feedback, negativ feedback samt ingen feedback. Instrumentet Intrinsic motivation inventory (IMI) användes för att mäta inre motivation som en funktion av fyra faktorer: intresse/nöje, upplevd kompetens, press/anspänning samt ansträngning. Resultaten visade att samtliga faktorer förutom ansträngning påverkades av vilken typ av feedback ryttaren fick. Intresse/nöje och upplevd kompetens var högst vid positiv feedback och lägst vid negativ feedback medan press/anspänning, som är negativt relaterat till inre motivation, var lägst vid positiv och högst vid negativ feedback. Av de 35 deltagarna var 19 kända av experimentledaren sedan tidigare. När tidigare känd/tidigare okänd användes som mellangruppsvariabel fanns en huvudeffekt för faktorn press/anspänning. De tidigare okända deltagarna upplevde högre anspänning än de tidigare kända deltagarna under alla betingelser. För faktorn ansträngning fanns en interaktionseffekt. De tidigare okända ansträngde sig mest vid positiv feedback och minst vid negativ feedback medan de tidigare kända deltagarna visade motsatta reaktioner. Störst effekt hade feedbacken på upplevd kompetens vilket kan leda till förbättrade prestationer. Slutsatsen av studien är att positiv feedback gynnar den inre motivationen hos ryttare och kan därmed förbättra deras utveckling och prestationer. / It is of utmost interest for teachers to increase student’s intrinsic motivation. Several previous studies have examined the impact of feedback on intrinsic motivation, but corresponding studies on riders are missing. Three individuals are involved at riding lessons – coach, rider and horse. The question therefore arises if the rider´s intrinsic motivation will be as affected by coaches’ feedback as in other sports. In this study, a within group design was used with 35 participating riders and three conditions: positive, negative or no feedback. The Intrinsic motivation inventory (IMI) was used to measure intrinsic motivation as a function of four factors: interest/joy, perceived competence, pressure/tension and effort. All factors except effort were affected by the type of feedback. Interest/joy and perceived competence were highest at positive and lowest at negative feedback, while pressure/tension that is negatively related with intrinsic motivation was lowest at positive and highest at negative feedback. Of the 35 participants, 19 were previously known by the experimenter. Previously known/unknown were used as a between factor variable. That revealed a main effect on pressure/tension. The previously unknown participants experienced more pressure/tension at all conditions. An interaction was revealed for perceived effort: the previously unknown stated most perceived effort at positive and least at negative feedback while the reactions were the opposite for the previously known. Feedback had greatest effect on perceived competence which may lead to better performance. The conclusion is that positive feedback increases the intrinsic motivation in riders and hence, is beneficial on their development and performance.

It has been observed that confusion exists in literature concerning the meaning and use of the term efficacy. Confusion is worsened by the use of the term as a general term describing agonist activity. The meaning of the terms intrinsic activity, efficacy and intrinsic efficacy as used in theoretical models of drug action was investigated. The classical occupation model, the two-state model, the ternary complex model (including conformational change and ideas surrounding G-proteins) and the operational model were studied in order to understand the historical and current usage of these terms. Although efficacy estimates are often reported as a molecular property, it was shown that agonist activity is tissue dependent and cannot be fully portrayed by an efficacy estimate. It was found that efficacy has a different definition in each model. This is not always recognized in literature. It was suggested that the term efficacy should only be used in the context of a specific model / Thesis (M.Sc. (Pharmacology))--North-West University, Potchefstroom Campus, 2007.

In this thesis, the tunneling between individual atomic layers in structures of Bi2Sr2CaCu2O8+x based high-temperature superconductors are experimentally studied employing the intrinsic Josephson effect. A special attention is paid to the fabrication of small mesa structures using micro and nanofabrication techniques. In the first part of the thesis, the periodic Fraunhofer-like modulation of the critical current of the junctions as a function of in-plane magnetic field is investigated. A transition from a modulation with a half flux quantum to a flux quantum periodicity is demonstrated with increasing field and decreasing junction length. It is interpreted in terms of the transformation of the static fluxon lattice of stacked, strongly coupled intrinsic Josephson junctions and compared with theoretical predictions. A fluxon phase diagram is constructed.Numerical simulations have been carried out to complement the experimental data. In the second part of the thesis, different resonant phenomena are studied in the dynamic flux-flow state at high magnetic fields, including Eck-resonances and Fiske steps. Different resonant modes and their velocities, including superluminal modes, are identified. In the third part, different experiments attempting to detect radiation from small mesa structures using different setups based on hot-electron bolometer mixers and calorimeters are described. No distinct radiation with emission powers higher than about 500pW could be detected. Furthermore, the interaction with external GHz-radiation is studied. Resonances attributed to an induced flux-flow are observed, and the reflectivity of the sample can be tuned by switching mesas between the superconducting and quasiparticle state. In the last part, the resistive switching of mesas at high bias is studied. It is attributed to a persistent electrical doping of the crystal. Superconducting properties such as the critical current and temperature and the tunneling spectra are analyzed at different doping states of the same sample. The dynamics of the doping is studied, and attributed to two mechanisms; a charge-transfer effect and oxygen reordering

It has been observed that confusion exists in literature concerning the meaning and use of the term efficacy. Confusion is worsened by the use of the term as a general term describing agonist activity. The meaning of the terms intrinsic activity, efficacy and intrinsic efficacy as used in theoretical models of drug action was investigated. The classical occupation model, the two-state model, the ternary complex model (including conformational change and ideas surrounding G-proteins) and the operational model were studied in order to understand the historical and current usage of these terms. Although efficacy estimates are often reported as a molecular property, it was shown that agonist activity is tissue dependent and cannot be fully portrayed by an efficacy estimate. It was found that efficacy has a different definition in each model. This is not always recognized in literature. It was suggested that the term efficacy should only be used in the context of a specific model / Thesis (M.Sc. (Pharmacology))--North-West University, Potchefstroom Campus, 2007.

Despite many advances in the design methods for compliant mechanisms, it is still not possible to know if a set of user-specifications has a solution. Furthermore, practical considerations such as failure limits and manufacturing limitations cannot be easily incorporated into existing methods. To address these issues, we have recently developed the concept of feasible stiffness and inertia maps. This thesis extends the concept of feasible maps and proposes another kind of maps that comprehensively depict the nonlinear kinetoelastostatic behaviour of compliant mechanisms. Feasible maps drawn as per user-specifications, with compliant mechanisms of the database overlaid on it, instantly inform the reader whether the specifications are feasible; whether the specifications are stringent; whether any mechanisms in the database meet the specifications, and whether any mechanism can be interactively modified to meet the specifications including size, strength and manufacturability. This thesis extends the earlier work on feasible maps by relaxing one condition that all beam segments in a compliant mechanism must retain their relative proportions. This is achieved by using size optimization. Thus, a certain degree of automation is brought into the procedure, which enhances the ease of use of the feasible maps. Illustrative examples are presented and implementation into a software is demonstrated. A major contribution of this work is the development of the concept of kinetoelastostatic maps of compliant mechanisms with fixed topology, shape, and relative proportions of beam segments in them. The map is drawn on a 2D plot using two non-dimensional quantities, one that captures the response of the mechanism and the other that combines the force, geometry, and material parameters. The map encloses a region that indicates the kinetoelastostatic capability of the mechanism. Another contribution of this work is the observation that the enclosed region can be parameterized using average slenderness ratio of the beam segments. The resulting curves help designers in assessing the capability and limits of a mechanism in terms of geometric advantage, mechanical advantage, normalized output displacement, inherent stiffness, etc. Numerous examples are presented to explain various uses of the non-dimensional maps.