Notre stratégie de stockage d’électrons repose sur la formation et la rupture de liaisons chimiques fonctionnant comme des réservoirs d’électrons. Le processus de formation réversible de liaisons est rendu possible grâce à la pré-organisation de groupements électroactifs – des pyridiniums – autour de plateformes aromatiques rigides et semi-rigides. Le relargage des électrons stockés au sein des réservoirs d’électrons par rupture de liaison suggère de manipuler des liaisons de nature affaiblie, c’est-à-dire allongées et contraintes stériquement, comme celles résultantes d’interactions hors-du-plan des groupements électrophoriques. Les contraintes stériques permettent ainsi la formation et la rupture de ces liaisons dans une gamme d’énergie raisonnable. Les pyridiniums sont des unités électrophoriques de choix dû à la versatilité de leurs propriétés de réduction. Les assemblages obtenus sont des systèmes bistables qui montrent des propriétés électrochimiques hystérétiques remarquables. En général, ce comportement repose sur la proche proximité des groupements électrophoriques qui permettent la formation d’une (ou plusieurs) orbitale(s) supramoléculaire(s) vacante(s) et liante(s) (SupLUMOs). Lors de la réduction, cette orbitale accueille deux électrons créant ainsi la liaison d’intérêt. Une famille de composés modèles a ainsi été conçue et synthétisée impliquant la formation réversible de liaisons homonucléaires (Csp3‒Csp3). Ces liaisons sont de nature localisée dans des systèmes à deux pyridiniums (bi-électroniques) et délocalisée dans des systèmes de plus de deux pyridiniums. / Our strategy to store electrons is based on chemical bond formation/cleavage being used as electron reservoirs. Reversible bond formation results from the preorganization of electrophoric moieties – pyridiniums – around aromatic rigid and semi-rigid scaffold. Using lower energy bonds is required to release stored electrons from the reservoirs. Such bonds can be obtained from sterically hindered out-of-plan bond formation between two electrophorical subunits. The resulting elongated bond can be cleaved in an available level of energy. Pyridiniums are prime candidates to achieve such properties based on their noteworthy redox behavior. The resulting molecular devices are bistable systems that display remarkable hysteretic electrochemical properties, based on close proximity of electrophoric subunits allowing one (or more) unoccupied supramolecular bonding orbital(s) (SupLUMOs). Upon reduction, two electrons are injected in this orbital resulting in the bond of interest. An entire family of compounds has been designed and synthesized to highlight reversible homonuclear bond formation (Csp3‒Csp3). Those bonds are localized in the case of a two-pyridiniums system, and delocalized when more pyridiniums are involved.

No description available.

Ce travail est consacré à l’étude et à la mise au point de récupérateurs d’énergie intégrés à une suspension automobile afin par exemple d’alimenter soit un microcontrôleur, soit des capteurs, soit de réaliser le contrôle santé des pièces ou encore de rendre l’amortisseur au sein d’une suspension d’un véhicule semi-actif autonome en fonction du niveau d’énergie disponible. Compte tenu des types de déplacement disponible dans la suspension, il est naturel de s’orienter vers des techniques électromagnétiques pour la récupération d’énergie liée aux grands déplacements et vers des techniques piézoélectriques pour les vibrations. L’utilisation de tels systèmes s’avère cependant complexe et un certain nombre de points techniques doivent être résolus pour les mettre en œuvre. En premier lieu, une parfaite connaissance des techniques de conversion piézoélectrique et électromagnétique est nécessaire. Dans ce but, le langage Bond Graph est utilisé et appliqué avec succès sur l’ensemble du système de suspension ainsi que sur les récupérateurs d’énergie en raison de sa capacité à traduire les effets physiques et les échanges énergétiques au sein de systèmes multiphysiques. D’autre part, des confrontations simulation/expérience sont réalisées en laboratoire sur chacun des récupérateurs d’énergie piézoélectrique et électromagnétique, afin de s’assurer du bon fonctionnement de ces systèmes lors de leurs intégrations dans un véhicule réel. Ainsi, des défauts de nature différente comme la force magnétique déformant le mouvement de translation de l’amortisseur, la mauvaise conduction des lignes de champ magnétique ou les endommagements du matériau piézoélectrique lors d’essais répétés, sont analysés dans les premiers démonstrateurs afin d'être ensuite corrigés. Enfin, un modèle global de suspension automobile intégrant simultanément les deux sous-systèmes de récupération d’énergie est étudié. Afin de compléter cette analyse, une modélisation du circuit de restitution et du stockage d’énergie est également proposée et permet une étude qualitative et quantitative des performances des systèmes de récupération d’énergie piézoélectrique et électromagnétique. Les résultats issus de ces modèles sont exploités dans le but de concevoir des récupérateurs d’énergie s’adaptant au mieux au domaine de l'automobile. Pour conclure, des tests sur route avec le récupérateur d’énergie piézoélectrique démontrent la validité de l’analyse théorique et la faisabilité des techniques développées. / This work is devoted to the study and the development of energy harvesters integrated in an automobile suspension, for example to supply either a microcontroller or sensors, or to perform an health check of parts or render semi-active the shock absorber within a suspension of an autonomous vehicle according to the level of energy available. Given the types of displacement available in the suspension, it is natural to move towards electromagnetic techniques for energy recovery related to large displacements and to piezoelectric techniques for vibrations. However, the use of such systems is complex and a number of technical issues need to be addressed to implement them. First, a perfect knowledge of piezoelectric and electromagnetic conversion techniques is required. To this end, the Bond Graph language is used and successfully applied to the entire suspension system as well as energy harvesters because of its ability to translate physical effects and energy exchanges into multiphysics systems. Furthermore, simulation / experiment confrontations are carried out in the laboratory on each of the piezoelectric and electromagnetic energy harvesters, to ensure the proper functioning of these systems during their integration into a real vehicle. Thus, defects of different nature such as the magnetic force deforming the translation movement of the damper, the poor conduction of the magnetic field lines or the damage of the piezoelectric material during repeated tests, are analyzed in the first demonstrators in order to be corrected. Finally, a global model of automobile suspension simultaneously integrating the two subsystems of energy recovery is studied. To complete this analysis, a modeling of the circuit of restitution and energy storage is also proposed and allows a qualitative and quantitative study of the performances of piezoelectric and electromagnetic energy recovery systems. The results from these models are used to design energy recovery systems that best fit the automotive field. To conclude, road tests with the piezoelectric energy harvesters demonstrate the validity of the theoretical analysis and the feasibility of the techniques developed.

近年來國內資本市場，因股票市場的熱絡交易而帶動公司及個人的理財風氣，投資標的種類不多及籌碼太少，一直是資本及股票市場正常發展的障礙之一，而證券主管機關亦深知，欲減少國內金融市場的投機色彩及暴漲暴跌的特性，唯有從增加供給面著手。因此，自民國七十八年起，主管機關即積極推介新的金融商品，首先推出的就是可轉換公司債(Conver-tible bond)，國內首宗正式發行可轉換公司債的公司是遠東紡織，之後有很多上市公司跟進，而推出後上市公司及投資人的反應均不錯，所以擬推出認股權證(Warrants)此一新產品。所謂認股權證是一種有價證券，其持有者有權在預定行使期間內，按認股契約所規定行使價格，向認股權證發行公司認購一定數量股票；而可轉換公司債是指在約定之一定期間內，以約定轉換條件，得轉換為可轉換公司債發行公司之普通股股票的一種公司債。認股權證如果與公司債搭配發行，與可轉換公司債同樣都賦予債權人轉變為股東之選擇權，兼具有公司債及股票性質。在國外的金融市場，可轉換公司債與認股權證是頗為流行且發展已臻成熟的產品，能提供更多公司籌措資金的管道及投資者的機會，但國內至今尚未推出認股權證，所以在我國發行可轉換公司債的熱潮正方興未艾之時，盼能參照國內外可轉換公司債及國外認股權證的法令規定，使國內認股權證能早日實施，況且此兩種新金融商品之投資性質很類似，相信此兩種商品在國內推出，對國內金融市場的發展有其正面的貢獻，因而引發本研究的動機。我國學術界近年來，亦有不少人士投入在認股權證及可轉換公司債的相關題材上進行研究，但這些研究多偏重在敘述與整理方面，而在評價模式及相關法律問題方面較為缺乏，因此本研究將著重此兩種產品在理論訂價模型與實務法律問題方面做深入探討。本人採用 Black & Scholes選擇權評價模式為基礎，再就其稀釋效果加以調整，則 Black & Scholes模型便可用來評價認股權證與可轉換公司債。國內發行可轉換公司債的相關法令規章則見諸於公司法、證券交易法、上市發行公司申請募集與發行轉換公司債處理準則內，本研究將詳細分析之。至於發行認股權證之相關法律問題是我們探討的重點，目前雖然證交法有認股權證的修正草案，但對於發行公司、投資人的權益尚未臻全，因而為了順利推動此類商品，宜更深入訂定管理辦法，並與可轉換公司債的法令關係比較，使兩種產品的市場受到保護並能欣欣向榮。

自從2007年全球金融海嘯後，中國政府開始著手進行推進貨幣體系改革、東亞區域貨幣合作與人民幣國際化。其中人民幣國際化更是中國政府國際金融新策略的重點，目的是提升人民幣的國際地位，並降低中國對美元的依賴。2009年以來，中國開始透過「跨境貿易人民幣結算試點」和「發展香港人民幣境外業務」兩項具體策略來推進人民幣國際化。 本論文研究的主軸分為三部份來探討：首先對境外人民幣債券市場的發展沿革以及目前概況做介紹，其次是針對境外人民幣債券市場實務來做探討，第三部份是以投資人角度來看其對於境外人民幣債券的考量，包括投資誘因、須考量的風險。最後在本論文中以首件外資公司發行境外人民幣債券(麥當勞)和首樁台資企業發行境外人民幣債券(永豐餘)為實例個案，具體分析企業發行境外人民幣債券的目的，以及投資人如何看待日漸開放的境外人民幣市場，由此可推敲窺見全球對人民幣未來的期待。

This body of research investigated the bonding efficiency of self-etching primer adhesives to enamel and dentine with various surface characteristics. A series of preliminary experiments was carried out to determine the effect of operator experience, dentine tubule orientation, bond strength test method and resin composite material used on bond strengths. The results of the preliminary tests concluded that it is essential to develop skills in material handling and the test methods used; 2-step self-etching primer adhesives exhibit higher but more variable microshear bond strengths (µSBS) than ‘all-in-one’ adhesives on dentine at different depths and tubule orientations; fracture toughness and bond strength test results suggest that the fracture toughness of a resin composite may not be of significant influence on microtensile and µSBS tests outcomes for nano-filled hybrid materials. / An investigation of the bonding ability of self-etching primer adhesives under various tooth preparation conditions was carried out. Enamel and dentine specimens were prepared from human teeth and finished with various rotary cutting instruments and the erbium, chromium:yttrium, scandium, gallium, garnet laser. Specimens were bonded with two 2-step self-etching primer adhesives and two ‘all-in-one’ adhesives with a resin composite. The results showed that one of the 2-step adhesives exhibited higher but more variable µSBS than the ‘all-in-one’ adhesives and a silorane-based self-etching primer adhesive system to enamel and dentine. / The relationship between enamel microhardness and µSBS was evaluated. Enamel specimens were prepared and finished with one half of the surface tested for hardness using the Vickers test. The other half of the enamel surface was bonded using either a 2-step self-etching primer adhesive or an ‘all-in-one’ adhesive and a hybrid resin composite. Mean Vickers hardness numbers and µSBS for each enamel surface were calculated. Analysis using Pearson’s parametric test for regression analysis evaluated the correlation between Vickers hardness and µSBS. The results revealed a weak negative insignificant correlation between VHN and µSBS for the 2-step adhesive and no correlation for the ‘all-in-one’ adhesive. / The effect of conditioning and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on bonding to bleached and unbleached enamel was investigated. Four groups of enamel specimens: untreated control; bleaching with 16% carbamide peroxide gel for 90 min daily x 14 days; treated with CPP-ACP paste (Tooth Mousse, GC Corp., Japan) for 60 min daily x 7 days and bleached and CPP-ACP-treated were used. The specimens were divided into a further two groups and bonded with a total-etch adhesive or a 2-step self-etching primer adhesive. Specimens bonded with the self-etching primer adhesive were sub-divided into four conditioning subgroups before bonding: no conditioning; 30 – 40% phosphoric; 15% EDTA; 20% polyacrylic acid. Specimens were tested in shear mode until failure and analysed by 2-way ANOVA, one-way ANOVA and Tukey’s post-hoc test. The µSBS of the total-etch adhesive was not affected by enamel treatment. Bleaching reduced the µSBS of the self-etching primer adhesive but preconditioning with phosphoric acid and polyacrylic acid improved bond strengths after CPP-ACP application. Bond failure analysis revealed a predominance of adhesive failures after bleaching, but prior conditioning reduced the proportion of adhesive failures. Scanning electron microscopy (SEM) revealed that the interfacial morphology produced by the 2-step self-etching primer adhesive was independent of enamel treatment except after bleaching. Phosphoric acid etching was not inhibited by CPP-ACP treatment. Resin tag formation was observed with prior phosphoric acid and polyacrylic acid conditioning. / The effect of conditioning and CPP-ACP application on dentine bonding was also investigated. Dentine specimens with and without the smear layer were prepared and divided into a further two groups, CPP-ACP paste applied to one group for 60 min daily x 7 days and the other group was untreated. The two groups were divided into three subgroups for conditioning: no conditioning; 30 - 40% phosphoric acid; 20% polyacrylic acid. The dentine was bonded using a 2-step self-etching primer adhesive and an ‘all-in-one’ adhesive, and tested as previously described. Statistical analysis was carried out using one-way ANOVA and Tukey’s post-hoc test at α = 0.05. The results showed that the µSBS of both adhesives were not significantly affected on smear-covered dentine but was affected on smearless dentine. Conditioning did not improve bond strengths. Bond failure analysis showed more adhesive failures for the ‘all-in-one’ adhesive, particularly on smearless dentine and with prior polyacrylic acid conditioning. SEM revealed a similar morphology of the bonded interface for the 2-step self-etching primer adhesive regardless of conditioning; and areas of bond failures for the ‘all-in-one’ adhesive. / The 2-step self-etching primer adhesives exhibited higher bond strength and more regular bond integrity than the ‘all-in-one’ adhesives, as shown on the SEM observations. However, the ‘all-in-one’ adhesives exhibited less variability in bond strengths to tooth surface characteristics.

<p>Water is one of the most common compounds on earth and is essential for all biological activities. Water has, however, been a mystery for many years due to the large number of unusual chemical and physical properties, e.g. decreased volume during melting and maximum density at 4 °C. The origin of the anomalies behavior is the nature of the hydrogen bond. This thesis will presented an x-ray absorption spectroscopy (XAS) study to reveal the hydrogen bond structure in liquid water.</p><p>The x-ray absorption process is faster than a femtosecond and thereby reflects the molecular orbital structure in a frozen geometry locally around the probed water molecules. The results indicate that the electronic structure of liquid water is significantly different from that of the solid and gaseous forms. The molecular arrangement in the first coordination shell of liquid water is actually very similar as the two-hydrogen-bonded configurations at the surface of ice. This discovery suggests that most molecules in liquid water have two-hydrogen-bonded configurations with one donor and one acceptor hydrogen bond compared to the four-hydrogen-bonded tetrahedral structure in ice. This result is controversial since the general picture is that the structure of liquid water is very similar to the structure of ice. The results are, however, consistent with x-ray and neutron diffraction data but reveals serious discrepancies with structures based on current molecular dynamics simulations. The two-hydrogen-bond configuration in liquid water is rigid and heating from 25 °C to 90 °C introduce a minor change in the hydrogen-bonded configurations. Furthermore, XAS studies of water in aqueous solutions show that ion hydration does not affect the hydrogen bond configuration of the bulk. Only water molecules in the close vicinity to the ions show changes in the hydrogen bond formation. XAS data obtained with fluorescence yield are sensitive enough to resolved electronic structure of water molecules in the first hydration sphere and to distinguish between different protonated species. Hence, XAS is a useful tool to provide insight into the local electronic structure of a hydrogen-bonded liquid and it is applied for the first time on water revealing unique information of high importance.</p>

Water is one of the most common compounds on earth and is essential for all biological activities. Water has, however, been a mystery for many years due to the large number of unusual chemical and physical properties, e.g. decreased volume during melting and maximum density at 4 °C. The origin of the anomalies behavior is the nature of the hydrogen bond. This thesis will presented an x-ray absorption spectroscopy (XAS) study to reveal the hydrogen bond structure in liquid water. The x-ray absorption process is faster than a femtosecond and thereby reflects the molecular orbital structure in a frozen geometry locally around the probed water molecules. The results indicate that the electronic structure of liquid water is significantly different from that of the solid and gaseous forms. The molecular arrangement in the first coordination shell of liquid water is actually very similar as the two-hydrogen-bonded configurations at the surface of ice. This discovery suggests that most molecules in liquid water have two-hydrogen-bonded configurations with one donor and one acceptor hydrogen bond compared to the four-hydrogen-bonded tetrahedral structure in ice. This result is controversial since the general picture is that the structure of liquid water is very similar to the structure of ice. The results are, however, consistent with x-ray and neutron diffraction data but reveals serious discrepancies with structures based on current molecular dynamics simulations. The two-hydrogen-bond configuration in liquid water is rigid and heating from 25 °C to 90 °C introduce a minor change in the hydrogen-bonded configurations. Furthermore, XAS studies of water in aqueous solutions show that ion hydration does not affect the hydrogen bond configuration of the bulk. Only water molecules in the close vicinity to the ions show changes in the hydrogen bond formation. XAS data obtained with fluorescence yield are sensitive enough to resolved electronic structure of water molecules in the first hydration sphere and to distinguish between different protonated species. Hence, XAS is a useful tool to provide insight into the local electronic structure of a hydrogen-bonded liquid and it is applied for the first time on water revealing unique information of high importance.

The selective transformation of carbon-carbon and carbon-hydrogen bonds represents an attractive approach and rapidly developing frontier in synthesis. Benefits include step and atom economy, as well as the ubiquitous presence in organic molecules. Advances to this exciting realm of synthesis are described in this thesis with an emphasis on the development of catalytic, selective reactions under mild conditions. Additionally some applications of the methodologies are demonstrated. In Chapter 1, the first examples of inter-and intramolecular enantioselective conjugate alkenylations employing organostannanes are reported. A chiral, cationic Rh(I)-diene complex catalyzed the enantioselective conjugate addition of alkenylstannanes to benzylidene Meldrum’s acids in moderate enantiomeric ratios and yields. Notably, the cationic and anhydrous conditions required for the asymmetric alkenylation are complementary to existing protocols employing other alkenylmetals. In Chapter 2, a domino, one-pot formation of tetracyclic ketones from benzylidene Meldrum’s acids using Sc(OTf)3 via a [1,5]-hydride shift/cyclization/Friedel-Crafts acylation sequence is described. Respectable yields were obtained in accord with the ability to convert to the spiro-intermediate, and considering the formation of three new bonds: one C-H and two C-C bonds. An intriguing carbon-carbon bond cleavage was also serendipitously discovered as part of a competing reaction pathway. In Chapter 3, the pursuit of novel C-H bond transformations led to the development of non-carbonyl-stabilized rhodium carbenoid Csp3-H insertions. This methodology enabled the rapid synthesis of N-fused indolines and related complex heterocycles from N-aziridinylimines. By using a rhodium carboxamidate catalyst, competing processes were minimized and C-H insertions were found to proceed in moderate to high yields. Also disclosed is an expedient total synthesis of (±)-cryptaustoline, a dibenzopyrrocoline alkaloid, which highlights the methodology. In Chapter 4, the Lewis acid promoted substitution of Meldrum’s acid discovered during the course of the domino reaction was explored in detail. The protocol transforms unstrained quaternary and tertiary benzylic Csp3-Csp3 bonds into Csp3-X bonds (X = C, N, H) and has even shown to be advantageous with regards to synthetic utility over the use of alternative leaving groups for substitutions at quaternary benzylic centers. This reaction has a broad scope both in terms of suitable substrates and nucleophiles with good to excellent yields obtained (typically >90%).

Atoms construct the molecules and molecules construct the material substances (with the exceptions as well, e.g.., metals, where atoms directly construct the material substances). Intermolecular interactions play an important role in most of the branches of sciences, ranging from material sciences to biological sciences. Van der Waals interactions are weak intermolecular interactions while hydrogen bonding varies in strength from weak to strong (1 to 40 kcal/mol). The present work focuses on applying some theoretical methods (ab initio and Atoms in Molecules theory) on these interactions to differentiate them with physically meaningful parameters such as hydrogen bond radii and atoms in molecules theory parameters. 1)Defining and calculating H-bond radii have been done using atoms in molecules theory approach which can explain ruling out the presence or absence of an H-bond in an intermolecular interaction. 2) A blue-shift of 200 cm-1 for a weakly bound complex is unprecedented. Our studies on weakly bound complexes showed the blue-shift of 200 cm-1 for H3C•••CIF and shift has been found to be purely from the mixing of normal modes and not because of an interaction. 3)Methane, a symmetric top molecule can act both as H-bond acceptor and donor. The present work shows that methane is rather a better H-bond acceptor than a donor and all the calculated parameters are in favor of this description. 4) Microwave spectrometer is an ultimate tool (at least at present) for structural characterization of the weakly bound complexes accurately. The rotational spectrum of the weakly bound isotopomer weakly bound complexes accurately. The rotational spectrum of the weakly bound isotopomer 13CC5H6•••Ar, which is a symmetric top and gives only “B” rotational constant. Moreover, the A rotational constant of the complex is the same as the rotational constant for 13CC5H6, which has no dipole moment. C2H2 molecule is an astrophysically important molecule as it is present in asymptotic giant branch and T-type stars (Teff<3000K). Due to its various infrared active vibrational modes, C2H2 is one of the most important sources in cool stars. The production of C2H2 infrared spectroscopic data at high temperature is therefore essential to trace back physical characteristics of these objects and to model the radiative transfer in their envelope. The databases such as “HITRAN”, do not have enough data available for stimulating high temperature spectra. Keeping all these objectives in mind, high temperature emission spectrum of acetylene has been recorded around 3µm region of acetylene.