Master of Science / Department of Chemistry / Mark Hollingsworth / The crystal structures of the inclusion compounds 1,6-diisocyanohexane/urea and 1,6-dicyanohexane/urea were refined at several temperatures from X-ray data. These urea inclusion compounds are commensurate structures with host:guest ratios of 6:1. In contrast with the ordinary helical topology of the urea host, these structures have stacked loop topologies of the host hydrogen bonds and crystallize in space group P21/n. At room temperature, both structures are distorted along [001] from hexagonal metric symmetry. As in earlier studies of 1-chloro-6-cyanohexane/urea, cooling 1,6-diisocyanohexane/urea gives rise to an exothermic phase transition (Hº = -856 cal mol 1, Sº = -5 cal mol-1 K-1) at 175 K that results in the cooperative translation of guest molecules by 5.5 Å along the channel axis. In the low temperature form, 1,6-diisocyanohexane/urea is distorted along [100], much like X(CH2)6Y, where X, Y = Br, Cl. Although the crystal structure of 1,6-dicyanohexane/urea is essentially isomorphous with that of the high temperature form of 1,6-diisocyanohexane/urea, it does not undergo an equivalent phase transition at low temperatures. Both of these systems exhibit dynamic disorder between two gauche conformers of the guest, which have mean planes of the alkyl chains lying within 1º of [100] (major conformer) and approximately 14º from [001] (minor conformer). The temperature dependence of site occupancy factors for the disordered sites yielded enthalpy differences between major and minor sites in 1,6-diisocyanohexane/urea and 1,6-dicyanohexane/urea of 216 and 127 cal mol 1, respectively. Since the low temperature form of 1,6-diisocyanohexane/urea is distorted along [100], this is favored at low temperatures by an increased concentration of the major conformer, which predominates in 1,6-dibromohexane/urea and congeners. In 1,6-diisocyanohexane/urea, the phase transition to the low temperature form occurs at a threshold concentration for the major conformer of 67%. With its shallower temperature dependence, 1,6-dicyanohexane/urea should not reach this threshold population until approximately 92 K, at which temperature the system cannot overcome the barrier for cooperative translation of guests along the channel axis.

Accurate knowledge of stopping powers is essential for these for quantitative analysis and surface characterization of thin films using ion beam analysis (IBA). These values are also of interest in radiobiology and radiotherapy, and in ion- implantation technology where shrinking feature sizes puts high demands on the accuracy of range calculations. A theory that predicts stopping powers and ranges for all projectile-target combinations is needed. The most important database used to report the stopping powers is the SRIM/TRIM program developed by Ziegler and coworkers. However, other researchers report that at times, these values differ significantly from experimental values. In this study the stopping powers of Si, P and S ions have been measured in Ni, Cu, Ge and GaAs absorbers in the energy range ~ 2-10 MeV. For elemental films of Ni, Cu and Ge, the stopping of heavy ions was measured using a novel ERD (Elastic Recoil Detection) based technique. In which an elastically recoiled lighter atom is used to indirectly measure the energy of the incoming heavy ion using a surface barrier detector. In this way it was possible to reduce the damage and to improve the FWHM of the detector. The results were compared to SRIM-2000 predictions and other experimental measurements. A new technique derived from Molecular Beam Epitaxy (MBE) was developed to prepare stoichiometric GaAs films on thin carbon films for use in transmission ion beam experiments. The GaAs films were characterized using X-ray Photoelectron Spectroscopy (XPS) and Particle Induced X-ray Emission (PIXE). These films were used to investigate the stopping powers of energetic heavy ions in GaAs and to provide data for the calculation of Bethe-Bloch parameters in the framework of the Modified Bethe-Bloch theory. As a result of this study, stopping power data are available for the first time for Si and P ions in the energy range 2-10 MeV stopping in GaAs absorbers.

by Choy Wing Hong. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 95-102). / Text in English; abstract also in Chinese. / by Choy Wing Hong. / ABSTRACT --- p.vi / ACKNOWLEDGEMENTS --- p.x / LIST OF FIGURES --- p.xi / LIST OF TABLES --- p.xiii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- Surface passivation techniques --- p.2 / Chapter 1.2.1 --- Sulfide solution passivation --- p.2 / Chapter 1.2.2 --- Gas-phase sulfide passivation --- p.3 / Chapter 1.2.3 --- Ultra-violet and ozone exposure --- p.4 / Chapter 1.3 --- Surface structure of sulfide-passivated surface --- p.5 / Chapter 1.4 --- Surface structure of ultra-violet/ozone oxidation --- p.8 / Chapter 1.5 --- Objectives of present study --- p.10 / Chapter Chapter 2 --- Instrumentation --- p.12 / Chapter 2.1 --- Introduction --- p.12 / Chapter 2.2 --- Atomic force microscopy (AFM) --- p.12 / Chapter 2.2.1 --- The development of AFM --- p.12 / Chapter 2.2.2 --- Basic principles of AFM --- p.12 / Chapter 2.2.3 --- Forces and their relevance to atomic force microscopy --- p.13 / Chapter 2.2.3.1 --- Van Der Waals forces --- p.15 / Chapter 2.2.3.2 --- Repulsive forces --- p.15 / Chapter 2.2.3.3 --- Capillary forces --- p.15 / Chapter 2.2.4 --- Displacement sensor of AFM --- p.15 / Chapter 2.2.4.1 --- Electron tunneling --- p.16 / Chapter 2.2.4.2 --- Optical interference --- p.16 / Chapter 2.2.4.3 --- Laser beam deflection --- p.16 / Chapter 2.2.5 --- Instrument specification --- p.17 / Chapter 2.2.5.1 --- Contact mode AFM --- p.17 / Chapter 2.3 --- X-ray photoelectron spectroscopy --- p.19 / Chapter 2.3.1 --- The development of XPS --- p.19 / Chapter 2.3.2 --- Basic principles of XPS --- p.19 / Chapter 2.3.3 --- XPS experiments --- p.23 / Chapter 2.3.4 --- Quantitative analysis --- p.26 / Chapter 2.3.4.1 --- Atomic concentration of a homogenous materials --- p.26 / Chapter 2.3.4.2 --- Layer structure --- p.27 / Chapter 2.4 --- Rutherford backscattering spectrometry (RBS) --- p.29 / Chapter 2.4.1 --- Basic principles --- p.29 / Chapter 2.4.2 --- Kinematics --- p.29 / Chapter 2.4.3 --- Channeling --- p.31 / Chapter Chapter 3 --- Surface treatments --- p.32 / Chapter 3.1 --- Semiconductor wafer --- p.32 / Chapter 3.2 --- Cleaning procedures --- p.32 / Chapter 3.3 --- Polysulfide passivation --- p.34 / Chapter 3.4 --- UV/Ozone oxidation --- p.39 / Chapter Chapter 4 --- Surface roughness and oxide contents of sulfide passivation --- p.41 / Chapter 4.1 --- Introduction --- p.41 / Chapter 4.2 --- Experimental methodology --- p.42 / Chapter 4.3 --- Etching --- p.44 / Chapter 4.3.1 --- Etching effect of polysulfide solution --- p.45 / Chapter 4.3.2 --- Possible consequences of the etching effect --- p.45 / Chapter 4.4 --- Oxide contents --- p.47 / Chapter 4.4.1 --- Oxide gained during polysulfide solution treatment --- p.47 / Chapter 4.4.2 --- Oxide gained after polysulfide passivation --- p.47 / Chapter 4.5 --- Surface roughness --- p.49 / Chapter 4.5.1 --- Surface roughness after different passivation methods --- p.49 / Chapter 4.5.2 --- The sticking probability after different passivations --- p.51 / Chapter 4.6 --- The spiral ladder of solution-phase passivation --- p.55 / Chapter 4.7 --- Conclusions --- p.58 / Chapter Chapter 5 --- Sulfide on Ge/GaAs heterojunction --- p.59 / Chapter 5.1 --- Introduction --- p.59 / Chapter 5.1.1 --- Band structure of Ge/GaAs heteroj unction --- p.59 / Chapter 5.1.2 --- Lattice match of Ge/GaAs heteroj unction --- p.60 / Chapter 5.1.3 --- The growth of Ge on GaAs using molecular beam epitaxy --- p.62 / Chapter 5.2 --- The growth of Ge on GaAs using thermal pulse annealing --- p.63 / Chapter 5.3 --- Sulfide as an atomic interdiffusion barrier --- p.65 / Chapter 5.3.1 --- Experimental methodology --- p.65 / Chapter 5.3.2 --- Crystallinity of Ge --- p.67 / Chapter 5.3.3 --- Results and discussions --- p.67 / Chapter 5.3.3.1 --- RBS and XPS results --- p.67 / Chapter 5.3.3.2 --- AFM and I-V results --- p.71 / Chapter 5.4 --- Conclusions --- p.71 / Chapter Chapter 6 --- UV/03 on Ge/GaAs heterojunction --- p.72 / Chapter 6.1 --- Introduction of UV/o3 oxidation --- p.72 / Chapter 6.2 --- UV/o3 oxidation on GaAs --- p.74 / Chapter 6.3 --- Ge on UV/o3 treated GaAs --- p.76 / Chapter 6.3.1 --- Experimental methodology --- p.76 / Chapter 6.3.2 --- Crystallinity of Ge --- p.77 / Chapter 6.3.3 --- AFM results --- p.77 / Chapter 6.3.4 --- RBS results --- p.80 / Chapter 6.4 --- Diodes --- p.82 / Chapter 6.4.1 --- Fabrication of diode --- p.82 / Chapter 6.4.2 --- Diode characteristics --- p.84 / Chapter 6.4.3 --- I-V characteristics --- p.90 / Chapter 6.5 --- Conclusions --- p.90 / Chapter Chapter 7 --- Conclusion and future work --- p.93 / Chapter 7.1 --- Conclusions --- p.93 / Chapter 7.2 --- Future works --- p.94 / Reference --- p.95

IQE (Europe) Ltd. manufactures group III/V compound semiconductor material structures, using the Metal Organic Vapour Phase Epitaxy process. The manufactured ranges of semi-conducting materials are relative to discrete or multi-compound use of Gallium Arsenide or Indium Phosphide [III/V]. For MOVPE to compete in large-scale markets, the manufacturing process requires transformation into a reliable, repeatable production process. This need is identified within the process scrap percentage of the process when benchmarked against the more mature Si-CVD process. With this wide-ranging product base and different material systems, flexible processes and systems are essential. The negative impact however, of this demanded flexibility is a complex system, resulting in instability. Minor fluctuations in time, flow, pressure, temperature, or composition in the manufacturing process, will lead to characteristic differences in the produced material [product], when comparing the prescribed run to the actual run. The product profile changes very rapidly, correspondingly the failure profile of the process is equally as dynamic, it is essential therefore that the analysis and projected activities and actions can be identified and consolidated in a timely manner. This project evaluates the process used by IQEE to manufacture III/V compound semi-conducting material structures and uses the business performance to identify the process drivers. One year's [1997] business and process information is used for a single iteration of the improvement cycle. These drivers are then utilised as operators and offer the critical weaknesses in the process related to performance blockages. Some of the techniques utilised in the process evaluation and cause derivation; are original contributions specifically derived for use with a multi-platform complex process with multiple cause and effect operators. A double reporting FMEA contributes a differing rank for like machines running differing products, offering a machine specific failure profile. A novel composite of P-diagram and process flow techniques enables determination of activity influences confirming the key failure mechanism as previously identified by the business risk analysis. This project concludes by nominating the key failure mechanism accounting for 41% of the approximate 50% scrap figure identified again within the business risk analysis. The effects attributed to this failure mechanism are 2- dimensionally analysed utilising an original double operating FMEA, plotting effect to effect for the individual causes, offering a prioritised list of failure categories. The highest priority failure mode is addressed by an equipment design exercise, resulting in an overall 10% sales potential recontribution.

La première partie, « analyse morphologique, linguistique et stylistique de l’adjectif composé anglais » permet de faire un point sur ce que dit la littérature existante à propos de la manière dont la forme qui nous intéresse est construite. Nous interrogeons la manière dont le processus compositionnel donne naissance aux mots composés, avant de nous concentrer sur l’adjectif composé. Nous faisons une distinction entre composition et affixation ; puis nous établissons une liste des caractéristiques adjectivales de l’adjectif composé anglais. Le deuxième volet de ce premier mouvement est le lieu d’une étape importante de notre étude : la mise en place d’une typologie de l’adjectif composé anglais, construite à partir d’un relevé effectué dans huit œuvres du monde anglophone. Nous déterminons quels sont les cinq formats majeurs que l’adjectif composé adopte : nous mettons en place une analyse des relations syntaxiques et sémantiques au coeur des cinq formats qui dominent notre typologie, puis analysons l’apport stylistique de ces formes adjectivales composées aux oeuvres de notre corpus littéraire.La deuxième partie, « analyse prosodique de l’adjectif composé anglais », fait un état des lieux de la question de l’accentuation des adjectifs composés en lien, comme nous l’avons fait dans la première partie, avec ce qui est établi autour des autres mots composés, notamment les noms composés. L’aspect expérimental de cette deuxième partie prend la forme d’une étude phonologique de l’adjectif composé anglais en contexte théâtral. / The first part consists in a morphologic, linguistic and stylistic study of the English compound adjective. We draw a summary of what the existing literature has said over the years about the adjectival compound form, which allows us to question the morphology of the compound process and the way this phenomenon produces new items of language by associating two or more existing words. We interrogate the possibility of links between the different compound words, notably the connections between the English compound noun and the English compound adjective. This first part also draws boundaries between different processes of morphology; once the compounding process and the compound adjective are defined, we draw a list of the adjectival characteristics of the compound adjective. After having studied the theories surrounding the English compound adjective, we set a typology of the form. This typology is built using the 1,521 instances found in 8 pieces of literature. We then focus our attention on the five most common syntactic formats found in our corpus: each of them is analyzed syntactically and semantically, then stylistically by examining how the authors of our corpus make use of the English compound adjective. The second part of the dissertation proposes to study the English compound adjective and its accentuation. We investigate what has been said in the existing literature about the accentuation of compound forms, notably on the accentuation of compounds versus phrases and on compound nouns.

Rheumatoid arthritis (RA) is a common chronic inflammatory disease that affects about 1% of the Western population. Glucocorticoids (GC) are widely used for the treatment of RA and other immune-mediated diseases, such as asthma, but their use is associated with adverse effects on bone metabolism. Because of that, new selective GC receptor (GR) agonists (SEGRAs) with the potential for an improved risk/benefit profile have been developed. Compound A (CpdA) is a novel SEGRA, which showed an improved risk/benefit profile concerning glucose metabolism, however the effects on bone are not well investigated yet. Initial in vitro studies of our group showed bone-sparing potential of CpdA. The aim of this study was to investigate whether CpdA also possesses beneficial effects on bone in vivo. Therefore, the first step was to explore the effects of CpdA on healthy bone metabolism, followed by the analysis of the anti-inflammatory potential in a murine model of RA. To mimic the effects of continuous therapy, bone loss was induced in FVB/N mice by implanting slow-release pellets containing placebo, prednisolone (PRED; 3.5 mg), or CpdA (3.5 mg). After four weeks, mice were killed and the effects on the skeleton were examined. By performing in vitro studies with human bone marrow stromal cells (BMSC) and murine osteocyte-like cells (MLO-Y4 cells), the underlying mechanisms were assessed. Here, we focused on the RANKL/OPG ratio as a marker for the osteoclastogenic potential as well as on the Wnt signaling pathway. Whereas PRED reduced the total and trabecular bone density in the femur and in the spine, CpdA did not influence these parameters. These results were confirmed by histomorphometry as the mineral apposition rate was decreased by PRED whereas the number of osteoclasts was increased. Reduced bone formation was furthermore paralleled by a decline in the serum bone formation marker pro-collagen type 1 N-terminal peptide (P1NP) and decreased skeletal expression of osteoblast markers, as well as increased serum levels of the osteoblast inhibitor dickkopf-1 (Dkk-1). Additionally, serum CTX-1 and the RANKL/OPG ratio in the bone tissue were increased by PRED. None of these effects were observed with CpdA. Moreover, CpdA did not increase the RANKL/OPG ratio in MLO-Y4 cells and failed to transactivate Dkk-1 expression in bone tissue, BMSC, and osteocytes. To analyze the anti-inflammatory properties of CpdA, arthritis was induced in DBA/1 mice by injection of type II collagen. After disease onset, mice were treated for ten days with PBS (placebo), dexamethasone (DEX; 100 µg/mouse), or CpdA (300 µg/mouse). The latter was able to decrease disease activity, paw swelling, and paw temperature, but was less potent compared to DEX. In addition, T cells isolated from CpdA- and DEX-treated animals were less active based on proliferation rates after stimulation with type II collagen and produced smaller amounts of interferon-γ as compared to T cells from PBS-treated mice. The weaker potency of CpdA as compared to DEX in preventing infiltration of inflammatory cells, induction of osteoclastogenesis, and destruction of articular cartilage was confirmed by histological assessment of the joints. While CpdA was unable to prevent inflammation-induced bone loss, it did not aggravate bone loss or alter bone density in healthy control mice. In conclusion, this study underlines the bone-sparing potential of CpdA compared to conventional GC in a murine model of GC-induced bone loss. Even though a moderate anti-inflammatory potential of CpdA was demonstrated, it was unable to prevent inflammation-induced bone loss. Despite the bone-sparing effects of CpdA in healthy mice, its narrow therapeutic window limits its use in clinical practice. Nevertheless, this study highlights important molecular mechanisms of GC-induced bone loss showing that by avoiding increases in the RANKL/OPG ratio or Dkk-1 in osteoblast lineage cells, GC-induced bone loss may be improved. / Rund 1% der westlichen Bevölkerung leidet an rheumatoider Arthritis, einer chronischen Entzündung der Gelenke. Für deren Behandlung werden häufig Glukokortikoide (GC) eingesetzt. Trotz ihrer potenten entzündungshemmenden Wirkung ist ihr Einsatz aufgrund der negativen Auswirkungen auf den Knochenstoffwechsel eingeschränkt. Um ein besseres Risiko/Nutzen-Profil zu erzielen, wurden selektive GC-Rezeptoragonisten (SEGRAs) entwickelt, die weiterhin potent anti-inflammatorisch wirken, während negative metabolische Effekte ausbleiben. Compound A (CpdA) ist ein Vertreter dieser Gruppe, der in Mäusen ein verbessertes Behandlungsprofil hinsichtlich des Glukosestoffwechsels zeigte. Die Wirkung auf den Knochen wurde bisher nur unzureichend untersucht. Erste in vitro Ergebnisse unserer Gruppe zeigten knochenfördernde Eigenschaften von CpdA. Ziel dieser Arbeit war es zu untersuchen, ob CpdA auch in vivo ein knochenschonendes Potenzial besitzt. Dafür wurden zunächst die Effekte von CpdA auf den gesunden Knochenstoffwechsel untersucht, um anschließend seine Wirkung in einem Mausmodell der rheumatoiden Arthritis zu testen. Um die Effekte einer Dauertherapie mit CpdA nachzustellen, wurden Slow-release-Pellets mit Plazebo, Prednisolon (PRED; 3,5 mg) beziehungsweise CpdA (3,5 mg) in FVB/N-Mäuse implantiert. Nach vier Wochen wurden die Effekte der Substanzen auf den Knochen untersucht. Um mögliche zugrundeliegende Mechanismen zu eruieren, wurden humane Knochenmarkszellen und murine Osteozyten-ähnliche Zellen (MLO-Y4-Zellen) genutzt. In diesen wurde der Einfluss der Substanzen auf das RANKL/OPG-Verhältnis, als einen Marker der Osteoklastenfunktion, sowie auf Dickkopf-1, einen Inhibitor des Wnt-Signalwegs, getestet. Während PRED die totale und trabekuläre Knochendichte im Femur und der Wirbelsäule verminderte, zeigte CpdA keinen Einfluss auf diese Parameter. Diese Ergebnisse wurden durch die histomorphometrische Analyse bestätigt und zeigten des Weiteren, dass PRED die Mineralanbaurate reduzierte während es die Anzahl der Osteoklasten erhöhte. Die verminderte Osteoblastenfunktion ging mit einer Abnahme der Knochenformationsmarker im Serum und im Knochengewebe einher. Außerdem wurden der Resorptionsmarker im Serum und das RANKL/OPG-Verhältnis im Knochengewebe von PRED erhöht. Bei CpdA-behandelten Tieren wurden keine dieser Effekte beobachtet. Zudem wurde das RANKL/OPG-Verhältnis in vitro in MLO-Y4-Zellen durch CpdA nicht beeinflusst und auch die Transaktivierung von Dkk-1 im Knochengewebe, in Knochenmarkszellen und Osteozyten blieb aus, was somit eine mögliche Erklärung für die knochenschonende Wirkung von CpdA darstellen könnte. Um die entzündungshemmenden Eigenschaften von CpdA zu untersuchen, wurde mittels einer Kollageninjektion Arthritis in DBA/1-Mäusen induziert. Nachdem die Mäuse eine Arthritis entwickelt hatten, wurden sie jeden zweiten Tag über eine Dauer von zehn Tagen mit PBS (Vehikel), Dexamethason (DEX; 100 µg/Maus) oder CpdA (300 µg/Maus) behandelt. CpdA war in der Lage die Krankheitsaktivität, die Pfotendicke und die Pfotentemperatur zu senken. Dabei war es aber nicht so effektiv wie DEX. Außerdem konnte gezeigt werden, dass T-Zellen, die aus CpdA- und DEX- behandelten Tieren isoliert und mit Kollagen stimuliert wurden, basierend auf ihrer Proliferationsrate weniger aktiv waren und geringere Mengen an Interferon-γ produzierten, als T-Zellen, die aus PBS-behandelten Tieren entnommen wurden. Das schwächere entzündungshemmende Potenzial von CpdA, verglichen mit DEX, wurde mittels der histologischen Analyse der Gelenke bestätigt. Es konnte eine höhere Infiltration von Entzündungszellen, sowie eine erhöhte Osteoklastogenese und Knorpelzerstörung in CpdA-behandelten Tieren beobachtet werden. Obwohl CpdA nicht in der Lage war, vor dem entzündungsbedingten Knochenverlust zu schützen, verschlimmerte es weder den Knochenverlust, noch veränderte es die Knochendichte in gesunden Kontrollmäusen. Diese Studie zeigt das knochenschonende Potenzial von CpdA in einem Mausmodell des GC-induzierten Knochenverlustes und bestätigt die moderaten entzündungshemmenden Eigenschaften von CpdA in vivo. Trotz der knochenschonenden Effekte von CpdA in gesunden Mäusen wird sein Einsatz in der klinischen Praxis durch die schmale therapeutische Breite erschwert. Trotz alledem deutet unsere Studie mit CpdA auf wichtige molekulare Mechanismen hin. Somit könnte durch das Verhindern der Erhöhung des RANKL/OPG-Quotienten oder von Dkk-1 in osteogenen Zellen, der durch GC verursachte Knochenverlust möglicherweise verhindert werden.

No description available.

Earcons are commonly used by sound designers in order to support visual cues in a game andto make a gaming experience more enjoyable. This study covers two earcons’ attributes: rhythm and timbre. Rhythm and timbre attributes were chosen according to the earcon sounddesign guidelines from the previous studies. An experiment in a form of a video game was conducted in order to research whether one of the conditions can increase a players’performance. A subject had to choose the correct key to the door in order to go to the next location. There were 3 different locations and there were totally 5 different own-designed earcons: 1 incorrect earcon in the both conditions and 2 different correct earcons in each condition. 20 subjects with various gaming experience from the Luleå University of Technology participated in the experiment. The subjects were randomly divided into two groups with different conditions: rhythm and timbre. The amount of wrong trials and completion time were analyzed for each condition and the results were given with the help of Mann-Whitney U-test and t-test calculations. The results of U-test showed that there was a significant difference between two groups in terms of the wrong trials amount. Group with rhythm condition showed better performance in terms of the wrong trials amount. The t-test showed a significant difference between the two groups in terms of completion time. Group with timbre condition showed better timing performance, although considering the analysis it did not increase their performance in terms of making correct choices. Further research might be recommended on comparing various earcon attributes in different ecologically valid scenarios.

L'emballage alimentaire est l'un des principaux acteurs de la préservation de la sécurité alimentaire et de la qualité au cours du stockage. Toutefois, de transferts de masse se produisent entre le l'emballage polymère et les denrées alimentaires. Polylactide (PLA) est un nouveau polymère biosourcé utilisé dans les applications d'emballage. Pour cela son interaction avec des denrées alimentaires a été étudiée dans des conditions réelles d'utilisation. Une méthodologie originale basée sur l'extraction multiple de l'espace de tête (MHE) et l'extraction multiple de l'espace de tête couplée à la microextraction sur phase solide (MHS-SPME) pour la mesure de sorption de composés organiques volatils (COVs) dans le PLA a été développé à des activités faibles et dans le domaine vitreux du polymère. Les COVs ayant une structure chimique modérément hydrophobe et des similarités de structure avec le PLA montrent une forte affinité pour le polymère. Plus surprenant, la forte sorption de composés aromatiques, notamment du benzaldéhyde, a été montrée. En mélange avec d'autres COVs le benzaldéhyde favorise leur sorption par un effet synergique. De plus, même à des activités faibles (0,01) et en présence de benzaldéhyde, la sorption de COVs induit une cristallisation du PLA. En contact avec un aliment aqueux, le PLA se montre résistant à l'hydrolyse et la sorption des matières grasses est faible, même en utilisant des conditions de stockage proches de sa transition vitreuse. L'apparition de COVs pendant le procédé de transformation a été étudiée par MHS-SPME. Des lactides, l'acétaldéhyde et le 2,3-pentanedione étaient détectés après extrusion et thermoformage. Les quantités des deux derniers composés diminuaient cependant pendant le procédé de thermoformage. / Packaging plays a major role in the preservation of food but mass transfer between the packaging material and foodstuff occurs during shelf life leading to the quality deterioration. Polylactide (PLA) is a novel packaging material; therefore its interaction with food was investigated at service conditions. The sorption of ethyl esters, benzaldehyde and 2-nonanone at low concentrations and in mixture and the effects on the thermal properties of PLA were studied. Multiple Headspace Extraction (MHE) and Multiple Headspace coupled to Solid Phase MicroExtraction (MHS-SPME) developed here allow to show a high affinity for moderately hydrophilic molecules sharing structure similarities with PLA such as ethyl acetate. However, a very high affinity for the aromatic structure of benzaldehyde was revealed which seems to favor interaction and sorption of the aroma compounds present in the mixture. At 0.01 activities, a plasticization by aroma compounds was observed and a solvent induced crystallization seemed to be correlated to the sorption of benzaldehyde. The contact between a flavored food emulsion and PLA, using conditions near the PLA glass transition showed that PLA hydrolysis was moderate and oil and aroma compound sorption was low. The formation of VOC during the PLA manufacturing process was assessed by MHS-SPME. Lactides, acetaldehyde and 2,3-pentanedione are VOCs present in PLA after extrusion and thermoforming. The two latter compounds increased after extrusion and then decreased or disappeared after thermoforming.

Enquête sur le fer(II) noyau transition de spin centrée métal coordonner avec des ligands photo-actif (isomérisation tran / cis) et l'étude de la lumière induite par le changement de spin conduit ligand (LD-LISC) propriétés en fer(II) fonctionnalisé complexes sous la forme de nanoparticules dispersées dans des films minces transparents. Pour cette étude, nous avons choisi un ensemble de complexes mononucléaires incorporant un ligand bipyridine substitué soit par un groupe méthyle (de la fonction électronique et de la structure) ou un groupe styryle (fonction photoactivable). L'introduction dans la sphère de trois de coordination (forte cas ligand-domaine) ou deux (intermédiaire force ligand-domaine) des ligands bipyridine (avec NCSe- co-ligands) a permis à la modulation de la résistance au ligand champ subi par l'ion métallique dans des systèmes différents. Propriétés de commutation optiques et thermiques des solides ont été étudiés dans les poudres polycristallines et de la dispersion des objets de taille réduite (micro, nanoparticules). Nous avons présenté l'élaboration et l'étude des micro- et nano-particules, complexes Fe(II) mononuclées non-ioniques, y compris ligand bidenté (4,4-méthyl-2,2 'bipyridine, Me₂-bpy) ont été sélectionnés. La synthèse de nano-et micro-objets a nécessité l'adaptation de la méthode (précipitation rapide anti-solvant). Il a été réalisé avec ionique [Fe(L)₃](NCSe)₂ précurseurs en jouant avec l'équilibre chimique pour induire la précipitation de connexes neutre Fe(L)₂(NCSe)₂ espèces. Nano et micro-cristaux de Fe(Me₂-bpy)₂(NCSe)₂ avec des tailles de 56 à 1200 nm ont été caractérisés et très dilués dans des films minces polymères pour optimiser l'absorption de la lumière et de l'étude des processus photocommutation. Fe (Me₂-bpy)₂(NCSe)₂ sous la forme de nano-et micro-particules, traitées dans des films polymères minces ont montré à spin-croisé thermique centrée à des températures supérieures à la température ambiante; pas d'effet significatif de l'environnement a été détectée. Nous avons étudié la réactivité photochimique de la precusors ioniques [Fe(msbpy)₃](NCSe)₂ (msbpy = trans et cis-isomères de 4-méthyl-4'-styryl-2,2 '-bipyridine), a été d'abord sondé en solution. Il a été établi que les cis isomérisation trans de 4-méthyl-4'-styryle 2,2 bipyidine a lieu d'une manière quantitative lorsque le complexe Fe(II) diamagnétique a été exposé à une lumière bleue (405 nm); cette réaction peut être partiellement inversée par une excitation UV. Nous avons élaboré des nanoparticules dérivées croisées sur la base du Fe(II) sont décrits; la commutation de ces particules (60nm) embarqués dans des films minces de PMMA et l'effet LD-LISC sont étudiés. Dans l'environnement très confiné de nanoparticules, la Feᴵᴵ(t-msbpy)₂(NCSe)₂ complexe réagit aussi lors de l'irradiation. La combinaison des UV-Vis, Raman et mesures photomagnétiques des matériaux hautement diluées nous a permis d'analyser l'effet de l'irradiation de lumière et le comportement de commutation état de spin. L'étude de Feᴵᴵ(t-msbpy)₂(NCSe)₂a montré la présence à la température ambiante des différents processus en fonction de la longueur d'onde d'excitation: un procédé de ligand centrée (trans à cis isomérisation, 365 nm) et un métal un centré (entraînant un changement MLCT, 405 nm). / Investigation of the iron(II) metal-centered spin-crossover core coordinate with photo-active ligands (tran / cis isomerization) and study of the ligand-driven light-induced spin change (LD-LISC) properties with functionalized iron(II) complexes in the form of nanoparticles dispersed in transparent thin films. For this investigation, we have selected a set of mononuclear complexes incorporating a bipyridine ligand substituted either with a methyl group (electronic and structural function) or a styryl group (photoactivable function). The introduction in the coordination sphere of three (strong ligand-field case) or two (intermediate ligand-field strength) bipyridine ligands (with NCSe- co-ligands) has allowed the modulation of the ligand-field strength experienced by the metal ion in different systems. Optical and thermal switching properties of solids have been investigated in polycrystalline powders and in dispersion of size-reduced objects (micro-, nano-particles).We have presented elaboration and study of micro- and nanoparticles, non-ionic mononuclear FeII complexes including bidentate ligand (4,4’-methyl-2,2’-bipyridine, Me2-bpy) have been selected. The synthesis of nano- and micro-objects has required the adaptation of the method (sudden precipitation in antisolvent). It was achieved with ionic [Fe(L)3](NCSe)2 precursors by playing with chemical equilibrium for inducing the precipitation of related neutral Fe(L)2(NCSe)2 species. Nano- and micro-crystals of Fe(Me2-bpy)2(NCSe)2 with sizes 56-1200 nm were characterized and then highly diluted in polymeric thin films for optimizing light absorption and investigating photoswitching processes. Fe(Me2-bpy)2(NCSe)2) in the form of nano-and micro-particles, processed in thin polymeric films were shown to exhibit thermal spin-crossover centered at temperatures higher than room temperature; no significant effect of environment was detected.We have studied the photochemical reactivity of the ionic precusors [Fe(msbpy)3](NCSe)2 (msbpy = trans- and cis-isomers of 4-methyl-4’-styryl-2,2’-bipyridine,) was first probed in solution. It has been established that the cis to trans isomerization of 4-methyl-4’-styryl-2,2’-bipyidine takes place in a quantitative way when the diamagnetic FeII complex was exposed to a blue light (405 nm); this reaction can be partly reversed with a UV excitation.We have elaborated spin-crossover nanoparticles based on the Fe(II) complexes are described; the switching of these particles (60nm) embedded in PMMA thin films and the LD-LISC effect are investigated. In the highly confined environment of nanoparticles, the FeII(t-msbpy)2(NCSe)2 complex also reacts upon irradiation. The combination of UV-Vis, Raman and photomagnetic measurements of the highly diluted materials has allowed us to analyze the effect of light irradiation and the spin-state switching behavior. The study of FeII(t-msbpy)2(NCSe)2 has shown the occurrence at room temperature of different processes depending on the excitation wavelength: a ligand-centered process (trans-to-cis isomerization, 365 nm) and a metal-centered one (resulting in a MLCT change, 405 nm).