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Στην παρούσα εργασία μελετούμε την διέγερση ενός ατομικού συστήματος καλίου (Κ) από 2 παλμούς λέιζερ, έναν άντλησης και έναν σύζευξης, οι οποίοι έχουν μεταξύ τους κάποια χρονική καθυστέρηση, καθώς και την επίδραση που έχουν οι χρόνοι κρούσεων των ατόμων καλίου με τα άτομα ενός αδρανούς αερίου (buffer gas – Argon), στους χρόνους αποκατάστασης ηρεμίας των ατομικών συμφωνιών (coherence relaxation times – CRT). Συγκεκριμένα γίνεται θεωρητική μελέτη του παραπάνω συστήματος σε V-τύπου σχήμα διέγερσης 3 επιπέδων, με σκοπό την προσέγγιση πειραματικών τιμών που βρέθηκαν σε προηγούμενη εργασία. Ένας ισχυρός παλμός άντλησης διεγείρει διφωτονικά την μετάβαση |4S_1/2>↔|6S_1/2> και εσωτερικά παραγόμενες ακτινοβολίες γεννώνται στην ατομική διαδρομή |6S_1/2>↔|5P_3/2>↔|4S_1/2> (διαδρομή 1), ενώ ένας πολύ ασθενής παλμός σύζευξης επιδρά στην μετάβαση |4S_1/2>↔|5P_3/2>. Εδώ δείχνουμε την επίδραση διαφόρων παραμέτρων του συστήματος στη δυναμική του, και κυρίως την επίδραση της χρονικής καθυστέρησης (μεταξύ των εξωτερικών παλμών άντλησης – σύζευξης) και του χρόνου των κρούσεων. Ακόμη διακρίνουμε μεταξύ τους τις 2 διαφορετικές διαδικασίες με τις οποίες δημιουργούνται οι εσωτερικά παραγόμενες ακτινοβολίες, μια παραμετρικής φύσεως που δεν περιλαμβάνει μεταφορές πληθυσμών και είναι σύμφωνη, και μια ASE (amplified spontaneous emission) φύσεως που είναι μερικώς σύμφωνη, και περιλαμβάνει μεταφορές πληθυσμών. Επιπλέον διερευνάται πειραματικά ένα σύστημα σε Λ-τύπου σχήμα διέγερσης το οποίο είναι πολυεπίπεδο. Το ισχυρό λέιζερ άντλησης διεγείρει διφωτονικά την μετάβαση |4S_1/2>↔|6S_1/2>. Στο Λ σχήμα διέγερσης όμως δεν μας ενδιαφέρουν ανώτερες καταστάσεις από την |6S_1/2>, καθώς η αποδιέγερση γίνεται μέσω κατώτερων από αυτήν καταστάσεων, οπότε η μελέτη απλοποιείται και τελικά γίνεται για σύστημα 4ων επιπέδων. Εσωτερικά παραγόμενες ακτινοβολίες γεννώνται στην ατομική διαδρομή 1 που αναφέραμε στην προηγούμενη παράγραφο καθώς και στην ατομική διαδρομή |6S_1/2>↔|4P_3/2,1/2>↔|4S_1/2> (διαδρομή 2), ενώ ένας λίγο ασθενέστερος παλμός σύζευξης επιδρά στην μετάβαση |6S_1/2>↔|4P_3/2,1/2>. Στην μελέτη αυτή επικεντρωνόμαστε στην συνολική συμπεριφορά των εκπομπών του καλίου (γραμμές D1 και D2 της μετάβασης |4P_3/2,1/2>↔|4S_1/2>), και παρατηρούμε μια ενίσχυση των εσωτερικά παραγόμενων ακτινοβολιών. Τέλος υπολογίζουμε τους χρόνους αποκατάστασης ηρεμίας της συμφωνίας (Coherence Relaxation Times – CRT) για το συγκεκριμένο σύστημα και τους συγκρίνουμε με αυτούς που υπολογίστηκαν πειραματικά σε προηγούμενη εργασία για V-τύπου σύστημα 3 επιπέδων. / In the present work we study the excitation of an atomic system (potassium vapors – K) by 2 laser pulses, one pumping the system and another establishing a coupling between certain atomic states. These 2 pulses (pump – coupling) have a temporal delay. The influence of collision times (between potassium and buffer gas atoms) on the coherence relaxation times (CRT) is also investigated. More specifically a theoretical approach of the aforementioned system in a 3-level V-type excitation scheme is being done, for the purpose of approximating some experimental values of a previous study. A strong pumping pulse excites the two-photon transition |4S_1/2>↔|6S_1/2> and internally generated radiations are produced in atomic path |6S_1/2>↔|5P_3/2>↔|4S_1/2> (path 1), while a very weak coupling pulse is introduced in transition |4S_1/2>↔|5P_3/2>. We show in this part the influence of different system parameters on the system’s dynamics, and especially the influence of the temporal delay (between the pump and coupling pulses) and collision times. Also we separate the 2 different mechanisms that cause the internally generated radiations. A parametric mechanism which is coherent and doesn’t include population transfer, and an ASE (Amplified Spontaneous Emission) or SHRS (Stimulated Hyper-Raman Scattering) mechanism which is partially coherent and includes population transfer. Furthermore the behavior of a 4-level Λ-type excitation scheme is being investigated experimentally. A strong pumping pulse excites the two-photon transition |4S_1/2>↔|6S_1/2>. In a Λ type excitation scheme the atomic states that lie higher than state |6S_1/2> are not of interest, because de-excitation occurs through lower-laying atomic states. So we focus our study on a simpler 4 level system. Internally generated radiations are produced in atomic path 1, which was mentioned in the last paragraph, and also in atomic path |6S_1/2>↔|4P_3/2,1/2>↔|4S_1/2> (path 2). A weaker coupling laser as introduced in transition |6S_1/2>↔|4P_3/2,1/2>. In this part of the study we focus on the overall behavior of the D1 and D2 emission lines of potassium (occurring from the transition |4P_3/2,1/2>↔|4S_1/2>) and we observe an amplification of the internal radiations. Finally we calculate the CRT times for this specific system and we compare them with those values that were calculated experimentally in a previous work for a V-type system.

L'utilisation de techniques de spectroscopie cohérente comme la diffusion Raman anti-Stokes cohérente (DRASC) sont communément utilisées pour l'analyse quantitative de milieux réactifs.Dans le cadre des progrès récents des sources lasers et des détecteurs, ce travail de thèse propose une adaptation de la technique de mesure de température au régime des impulsions ultra-courtes (femtoseconde, picoseconde) à haute cadence.Le développement d'un dispositif expérimental de DRASC en régime hybride fs/ps utilisant un laser femtoseconde et un réseau de Bragg en volume a permis de générer une impulsion de sonde de 30 ps. Dans la configuration choisie pour ce travail, la résolution spectrale est de 0,7 cm-1, ce qui réprésente l'état de l'art. Ce dispositif est appliqué à la spectroscopie ro-vibrationnelle de plusieurs espèces moléculaires.Pour décrire l'interaction dans ce régime temporel, un modèle de simulation des spectres DRASC est implémenté. Cette modélisation prend notamment en compte le profil en amplitude et phase de la sonde ainsi que son retard par rapport à l'excitation femtoseconde. L'influence des collisions moléculaires est discutée dans le cadre du régime hybride.Les ajustements des spectres calculés sur des spectres expérimentaux enregistrés dans l'air ambiant et dans une flamme de prémélange CH4/air, permettent de valider la modélisation proposée dans ce travail. En particulier, la température est mesurée à froid et à chaud à pression atmosphérique, avec une précision comparable à l'état de l'art dans le régime hybride fs/ps.Ce travail permet d'obtenir des résultats probants, et de valider la pertinence du montage développé pour la thermométrie. Fort de ces résultats, des applications en chambre de combustion réelles sont envisagées à court terme à l'ONERA, notamment par l'extrapolation du modèle à haute pression. / Coherent spectroscopy such as Coherent Anti-Stokes Raman Scattering (CARS) is commonly used for the study of reactive media.Following the recent progress encountered in laser sources and detectors, this thesis work proposes an adaptation of the technique for temperature measurements that exploits the ultra-short pulse regime (femtosecond, picosecond) to operate at high repetition-rate.The developed hybrid fs/ps-CARS setup delivers a 30-ps probe pulse using a femtosecond laser source and a Volume Bragg Grating. The obtained spectral resolution is 0,7 cm-1, which represents, within this pulse generation framework, the state of the art. This setup is applied to ro-vibrational spectroscopy of several molecular species.The interaction in the hybrid regime is described through a CARS simulation model that has been implemented. The modelling takes into account both the amplitude and the phase profiles of the probe pulse, and its delay to the femtosecond excitation. Influence of molecular collisions in the hybrid regime is also discussed.This modelling has been validated by fitting calculated spectra on experimental spectra recorded in ambient air, and in a premixed CH4/air flame. Temperature has been then measured at atmospheric pressure in these media. The precision is similar to the hybrid fs/ps-CARS thermometry state of the art.This work validates our N2 thermometry approach based on both the developed CARS setup and simulation model. Short term perspectives of this work are measurements on real combustion chambers at ONERA, by extrapolating our simulation model at high pressure.

Dans cette thèse, nous présentons un modèle d’analyse du discours économique et commercial à différents niveaux : énonciatif, lexical, syntaxique, sémantique, pragmatique et sociolinguistique. L’analyse détaillée du corpus spécialisé dans le domaine de l’économie peut grandement contribuer à la définition des caractéristiques spécifiques du discours économique et commercial. En fonction des résultats nous proposons des moyens pour l’application des résultats d’analyse à la didactique de la langue française en proposant les tâches à effectuer dans une perspective actionnelle. Notre hypothèse part du principe qu’en améliorant et en modernisant les méthodes d’apprentissage/enseignement de la langue française, nous répondrons aux demandes et aux besoins langagiers contemporains des apprenants, des entreprises et des institutions en Serbie. L’apprentissage des langues étrangères représente une des grandes priorités pour l’Union européenne dans le cadre de la stratégie Europe 2020. Chaque entreprise, qui veut être plus efficace, plus performante et plus compétitive sur le marché mondial, a besoin d’un personnel parlant la langue du client ou du partenaire d’affaires. Par conséquent, cela nécessite l’adaptation de l’enseignement de la langue française ou plus précisément le français sur objectif spécifique (FOS) ou le français de spécialité (FS) aux conditions socio-économiques actuelles en Serbie. À cet effet, nous consacrons une attention particulière au rôle de la langue dans le travail, à la description des enjeux de la communication professionnelle et aux relations économiques entre la Serbie et la France ainsi qu’avec le monde francophone. / In this paper, we present the analytical model of economic and commercial speech on different levels: expository, lexical, syntactic, semantic, pragmatic, and sociolinguistic. Detailed analysis specified in the area of economics can greatly contribute to defining the particularities of economic and commercial speech. According to the results, we offer some ways for involvement of the analyzed results to the teaching of the French language, suggesting various tasks, which would be done in action-oriented perspective.Our hypothesis represents the idea that while enriching and modernizing current methods of learning French language, we actually respond to requests and needs of a contemporary language to ones who learn it, to enterprises, and institutions in Serbia. Learning foreign languages presents one of the biggest priorities for European Union in means of their strategy called EU 2020. Every enterprise which has a goal to become more efficient, more successful, and more competitive on the world’s market, needs a person who speaks the language of a customer, or a business partner. According to that, it demands the adjustment of learning French language, and more precisely said, French language for specific purposes, or French language for personal communication under current socio-economic conditions in Serbia. In that purpose, we pay special attention to the role of language in work, in describing parts in professional communication and economic relations between Serbia and France, as well as the relations between Francophone countries.

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Rapid economic development has occurred during the past few decades in China with the Yangtze River Delta (YRD) area as one of the most progressive areas. The urbanization, industrialization, agricultural and aquaculture activities result in extensive production and application of chemicals. Organohalogen contaminants (OHCs) have been widely used as i.e. pesticides, flame retardants and plasticizers. They are persistent, bioaccumulative and pose a potential threat to ecosystem and human health. However, limited research has been conducted in the YRD with respect to chemicals environmental exposure. The main objective of this thesis is to investigate the contamination level, distribution pattern and sources of OHCs in the YRD. Wildlife from different habitats are used to indicate the environmental pollution situation, and evaluate selected matrices for use in long term biomonitoring to determine the environmental stress the contamination may cause. In addition, a method is developed for dicofol analysis. Moreover, a specific effort is made to introduce statistic power analysis to assist in optimal sampling design. The thesis results show extensive contamination of OHCs in wildlife in the YRD. The occurrences of high concentrations of chlorinated paraffins (CPs) are reported in wildlife, in particular in terrestrial species, (i.e. short-tailed mamushi snake and peregrine falcon). Impurities and byproducts of pentachlorophenol products, i.e. polychlorinated diphenyl ethers (PCDEs) and hydroxylated polychlorinated diphenyl ethers (OH-PCDEs) are identified and reported for the first time in eggs from black-crowned night heron and whiskered tern. High concentrations of octachlorodibenzo-p-dioxin (OCDD) are determined in these samples. The toxic equivalents (TEQs) of polychlorinated dibenzo-p-dioxin (PCDDs) and polychlorinated dibenzofurans (PCDFs) are at mean levels of 300 and 520 pg TEQ g-1lw (WHO2005 TEQ) in eggs from the two bird species, respectively. This is two orders of magnitude higher than European Union (EU) regulation limit in chicken eggs. Also, a novel pattern of polychlorinated biphenyls (PCBs) with octa- to decaCBs, contributing to as much as 20% of total PCBs therein, are reported in birds. The legacy POPs shows a common characteristic with relatively high level of organochlorine pesticides (i.e. DDT, hexacyclohexanes (HCHs) and Mirex), indicating historic applications. In contrast, rather low concentrations are shown of industrial chemicals such as PCBs and polybrominated diphenyl ethers (PBDEs). A refined and improved analytical method is developed to separate dicofol from its major decomposition compound, 4,4’-dichlorobenzophenone. Hence dicofol is possible to assess as such. Statistic power analysis demonstrates that sampling of sedentary species should be consistently spread over a larger area to monitor temporal trends of contaminants in a robust manner. The results presented in this thesis show high CPs and OCDD concentrations in wildlife. The levels and patterns of OHCs in YRD differ from other well studied areas of the world. This is likely due to the extensive production and use of chemicals in the YRD. The results strongly signal the need of research biomonitoring programs that meet the current situation of the YRD. Such programs will contribute to the management of chemicals and environment in YRD, with the potential to grow into the human health sector, and to expand to China as a whole. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 5: Submitted. Paper 6: Manuscript.</p><p> </p>

The vectorial nature (polarization) of light plays a significant role in light-matter interaction that leads to a variety of optical devices. The polarization property of light has been exploited in imaging, metrology, data storage, optical communication and also extended to biological studies. Most of the past studies fully explored and dealt with the conventional polarization state of light that has spatially symmetric electrical field geometry such as linear and circular polarization. Recently, researchers have been attracted to light whose electric field vector varies in space, the so-called optical vector vortex beam (VVB). Such light is expected to further enhance and improve the efficiency of optical systems. For instance, a radially polarized light under focusing condition is capable of a tighter focus more than the general optical beams with a uniform polarization structure, which improves the resolution of the imaging system [1]. Interaction of ultrafast laser pulses with matter leads to numerous applications in material processing and biology for imaging and generation of microfluidic systems. A femtosecond pulse, with very high intensities of (10^{12} - 10^{13} W/cm^2), has the potential to trigger a phenomenon of optical breakdown at the surface and therefore induce permanent material modification. With such high intensities and taking into account the fact that most materials possess large bandgap, the interaction is completely nonlinear in nature, and the target material can be modified locally upon the surface and even further in bulk. The phenomenon of optical breakdown can be further investigated by studying the nonlinear absorption. Properties like very short pulse duration and the high irradiance of ultrashort laser pulse lead to more precise results during the laser ablation process over the long pulsed laser. The duration of femtosecond laser pulse provides a high resolution for material processing because of the significant low heat-affected zone (HAZ) beyond the desired interaction spot generated upon irradiating the material. Under certain condition, the interaction of intense ultrashort light pulses with the material gives rise to the generation of periodic surface structures with a sub-micron periodicity, i.e., much smaller than the laser wavelength. The self-oriented periodic surface structures generated by irradiating the material with multiple femtosecond laser pulses results in improving the functionality of the material's surface such as controlling wettability, improving thin film adhesion, and minimizing friction losses in automobile engines, consequently, influences positively on many implementations. In this work, we introduced a new method to study complex polarization states of light by imprinting them on a solid surface in the form of periodic nano-structures. Micro/Nanostructuring of diamond by ultrafast pulses is of extreme importance because of its potential applications in photonics and other related fields. We investigated periodic surface structures usually known as laser-induced periodic surface structures (LIPSS) formed by Gaussian beam as well as with structured light carrying orbital angular momentum (OAM), generated by a birefringent optical device called a q-plate (QP). We generated conventional nano-structures on diamond surface using linearly and circularly polarized Gaussian lights at different number of pulses and variable pulse energies. In addition, imprinting the complex polarization state of different orders of optical vector vortex beams on a solid surface was fulfilled in the form of periodic structures oriented parallel to the local electric field of optical light. We also produced a variety of unconventional surface structures by superimposing a Gaussian beam with a vector vortex beam or by superposition of different order vector vortex beams. This thesis is divided into five chapters, giving a brief description about laser-matter interaction, underlying the unique characterization of femtosecond laser over the longer pulse laser and mechanisms of material ablation under the irradiation of fs laser pulse. This chapter also presents some earlier studies reported in formation of (LIPSS) fabricated on diamond with Gaussian. The second chapter explains the properties of twisted light possessing orbital angular momentum in its wavefront, a few techniques used for OAM generation including a full explanation of the q-plate from the fabrication to the function of the q-plate, and the tool utilized to represent the polarization state of light (SoP), a Poincar'e sphere. Finally, the experimental details and results are discussed in the third and fourth chapters, respectively, following with a conclusion chapter that briefly summarizes the thesis and some potential application of our findings.

The large influx of international students to universities of the developed world, the increased use of Problem-Based method of teaching and learning in the field of Health Education and growing awareness of the need to accommodate varying learning styles in any classroom are the three factors that influenced this research. This study was designed to investigate the effect of learning styles and demographic differences on performance in Biology when taught using two different methods of teaching. One was the teacher-directed Traditional Teaching and Learning (TTL) and the other was the student-centred Problem-Based Learning (PBL). The preferred learning styles of all Foundation Studies (FS) Biology students over four academic years at RMIT were determined using the Paragon Learning Style Inventory (PLSI). These students were taught two selected topics in Biology by the researcher using the two different methods and their performance assessed by a written test at the end of each topic. Two instruments were developed to assess student participation in PBL. The first instrument Students' Participation in Group Discussions (SPGD) rating scale was designed for teacher evaluation of student participation in PBL group discussions while the second instrument the Student Self Evaluation (SSE) rating scale was for self-evaluation by stud ents. Individual interviews provided students' views and opinions about their learning styles and the two teaching methods. The analysis of data was predominantly conducted by quantitative methods, supported by qualitative analysis of the interview data. Effect size analyses were used to investigate differences in performance under the two teaching methods on the basis of demographic and learning style differences. Further probes were conducted to elicit any interactions among the demographic variables and the learning style traits in their effect on performance under the two teaching methods and a quantitative measure for interaction was derived using effect sizes. While results confirmed some of the trends displayed by learning style traits in other disciplines, a number of interactions among variables were found to affect performance in Biology as well as performance under the two teaching methods. Gender, age, prior qualification and the language of instruction of prior education had various levels of interactions with the introvert/extrovert, intuitive/sensing, thinking/feeling and perceiving/judging learning traits and affected performance in Biology to varying extents. However, it was found that international students from diverse backgrounds were able to cope with both methods of teaching though there was a definite preference expressed for the traditional teacher directed method. The conclusions from this study have resulted in a number of recommendations for Biology educators, FS administrators, authors and all practitioners of PBL. Several suggestions have opened new avenues for future research. These recommendations for pedagogy and suggestions for future research can improve the outcomes of Biology education as well as other disciplines in related fields. As a consequence of this study two new instruments have been developed to assess student participation in the group discussions of PBL. These could prove to be valuable assessment tools for practitioners of this methodology.

The groundwater bacterium Pseudomonas fluorescens (CCUG 32456) isolated at a depth of 70 m in the Äspö Hard Rock Laboratory secretes a pyoverdin-mixture with four main components (two pyoverdins and two ferribactins). The dominant influence of the pyoverdins of this mixture could be demonstrated by an absorption spectroscopy study. The comparison of the stability constants of U(VI), Cm(III), and Np(V) species with ligands simulating the functional groups of the pyoverdins results in the following order of complex strength: pyoverdins (PYO) > trihydroxamate (DFO) > catecholates (NAP, 6­HQ) > simple hydroxamates (SHA, BHA). The pyoverdin chromophore functionality shows a large affinity to bind actinides. As a result, pyoverdins are also able to complex and to mobilize elements other than Fe(III) at a considerably high efficiency. It is known that EDTA may form the strongest actinide complexes among the various organic components in nuclear wastes. The stability constants of 1:1 species formed between Cm(III) and U(VI) and pyoverdins are by a factor of 1.05 and 1.3, respectively, larger compared to the corresponding EDTA stability constants. The Np(V)-PYO stability constant is even by a factor of 1.83 greater than the EDTA stability constant. The identified Np(V)-PYO species belong to the strongest Np(V) species with organic material reported so far. All identified species influence the actinide speciation within the biologically relevant pH range. The metal binding properties of microbes are mainly determined by functional groups of their cell wall (LPS: Gram-negative bacteria and PG: Gram-positive bacteria). On the basis of the determined stability constants raw estimates are possible, if actinides prefer to interact with the microbial cell wall components or with the secreted pyoverdin bioligands. By taking pH 5 as an example, U(VI)-PYO interactions are slightly stronger than those observed with LPS and PG. For Cm(III) we found a much stronger affinity to aqueous pyoverdin species than to functional groups of the cell wall compartments. A similar behavior was observed for Np(V). This shows the importance of indirect interaction processes between actinides and bioligands secreted by resident microbes.

Baltic archipelago areas have high nature values despite being polluted from various antrophogenic activities within the Baltic Sea catchment area and from long-range transport of airborne substances. The discovery of environmental problems in the Baltic Sea in the 1960s led to countermeasures that gradually gave results in reducing the toxic pollution, e.g. from PCBs. Today, much of the environmental management is focused on reducing the effects of eutrophication. There is a demand from society on science to develop strategies that can direct remedial actions so that the cost-effectiveness is maximised. This work focuses on how mass-balance models can be used to understand how coastal ecosystems are controlled by abiotic processes and to predict the response to changes in loading of different substances. Advection, sedimentation and burial are examples of general transport processes that are regulated by morphometrical characteristics, e.g. size, form, effective fetch and topographical openness. This is why different coastal areas have different sensitivity to loading of pollutants. A comparison of six phosphorus and chlorophyll models of different complexity showed that the model performance was not improved with more state variables of total phosphorus (TP) than two water and two sediment compartments. Modelling chlorophyll as a separate state variable did not improve the results for individual values compared to a simple regression against total phosphorus in surface water. Field investigations of the phosphorus content in accumulation sediments along the coast of Svealand showed a distribution pattern that probably is related to differences in the redox status. The average content of mobile phosphorus was much higher than previously found in offshore Baltic sediments indicating that sediments may play an important role for the phosphorus turnover in Baltic archipelago areas. A one-year field study to measure the levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in water, sediments and fish during different seasons was carried out in Kallrigafjärden Bay. The collected data set was used to test a mass-balance model for PCCD/F-turnover. It was possible to reproduce the concentrations of different PCDD/F-congeners with high accuracy using a general model approach, including one water compartment and two sediment compartments, indicating that the applied model has the necessary qualifications for successful predictions of PCDD/F-turnover in Baltic coastal areas. / Felaktigt tryckt som Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 736