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Methyl substituent effects on the rate of imine formation from ?,?-dimethylethylenediamines /Chou, Yueting January 1980 (has links)
No description available.
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Solid-state displacement reactions between metals and oxides /Yurek, Gregory John January 1973 (has links)
No description available.
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A Study of the effect of need value on substitution /Lotsof, Antoinette Bardwell January 1953 (has links)
No description available.
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I. Anti-tricyclo[3.1.1.0²̓⁴]heptyl and related systems ; II. Reductive cleavage of succinic esters under acyloin conditions /Creary, Xavier January 1973 (has links)
No description available.
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Colombia's resurrection: alternative development is the key to Democratic SecurityFleming, Adam Lum 09 1900 (has links)
Approved for public release; distribution unlimited / This thesis examines the role of alternative development in the Colombian and U.S. governments' counter drug strategies. Both governments include alternative development as a part of their policies, but provide limited funding to the programs when compared to the funding for forced eradication and security measures. Existing policies have produced reductions in drug cultivation in many areas and the Colombian government has made gains in security throughout the country, particularly the remote rural regions. These gains make conditions in Colombia suitable for large-scale alternative development supported by increased funding. Both governments are addressing components of successful alternative development programs, but funding disparities are hindering the effectiveness of the programs. While the international and European communities are staunch supporters of alternative development, the funding provided by them has been limited in scope because of disagreement with the U.S.-backed eradication policies. The U.S. and Colombian governments in conjunction with the international community must focus more on alternative development in order to consolidate the recent gains in democratic security. / Lieutenant, United States Navy
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Mechanisms of Methoxide Ion Substitution and Acid- Catalyzed Z/E Isomerization of N-MethoxyiminesDolliver, Debra D. 12 1900 (has links)
The second order rate constants for nucleophilic substitution by methoxide of (Z)- and (E)-O-methylbenzohydroximoyl fluorides [C6H4C(F)=NOCH3] with various substituents on the phenyl ring [p-OCH3 (1h, 2h), p-CH3 (1g, 2g), p-Cl (1f, 2f), p-H (1e, 2e), (3,5)-bis-CF3 (1i, 2i)] in 90:10 DMSO:MeOH have been measured. A Hammett plot of these rate constants vs σ values gave positive ρ values of 2.95 (Z isomer) and 3.29 (E isomer). Comparison of these rates with methoxide substitution rates for Omethylbenzohydroximoyl bromide [C6H4C(Br)=NOCH3] and Omethylbenzohydroximoyl chloride [C6H4C(Cl)=NOCH3] reveal an element effect for the Z isomers of Br:Cl:F(1e) = 2.21:1.00:79.7 and for the E isomers of Cl:F(2e) = 1.00:18.3. With the p-OCH3-imidoyl halides the following element effects are found: Br:Cl:F(1h) = 2.78:1.00:73.1 for the Z isomer and Br:Cl:F(2h) = 1.97:1.00:12.1 for the E isomer. Measurement of activation parameters revealed ∆S≠ = -17 eu for 1e and ∆S≠ = -9.9 eu for 2e. Ab initio calculations (HF/6-31+G*, MP2/6-31+G*//HF/6-31+G*, B3LYP/6- 31+G*//HF/6-31+G*, HF-SCIPCM/6-31+G*//HF/6-31+G*) were performed to define the reaction surface. These calculations demonstrate a relatively large barrier for nucleophilic attack in relation to halogen loss and support the experimental findings that this reaction proceeds by an addition-elimination mechanism (AN# + DN). The imidoyl fluorides have been used to synthesize highly functionalized O-methyloximes by reaction with enolate anions derived from malononitrile, ethyl cyanoacetate, and diethyl malonate. Acid-catalyzed isomerization of compounds containing the O-methyloxime moiety have been investigated with ab initio calculations (HF/6-31+G*, MP2/6- 31+G*//HF/6-31+G*, B3LYP/6-31+G*//HF/6-31+G*). Barriers for rotation around the C-N bond following protonation have been calculated. The calculated barriers are discussed in relation to an isomerization mechanism of protonation-rotation versus a nucleophilic catalysis.
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Oxo-halogénures de cobalt : Compréhension de l’influence des substitutions cationiques et anioniques / Cobalt oxo-halides : understanding of the influence of cationic and anionic substitutionIorgulescu, Mihaela Luciana 31 January 2012 (has links)
Ce travail a consisté en la synthèse, l’étude structurale et les caractérisations physico-chimiques de systèmes dérivés des polytypes 6H et 10H des perovskites hexagonales de formule BaMX0.2-xO3-δ (M=Co, Fe, Mn; X=F, Cl, Br). La compréhension des polytypes stables en fonction de la substitution sur les sites M et X a été entreprise via des analyses de la sous-stœchiométrie du réseau anionique. La réduction du métal s'accompagne de la stabilisation de polytypes incluant des oligomères triples d’octaèdres reliés par les faces. Une oxydation aura tendance à stabiliser des structures à sous-unités plus longues. Nous avons ainsi pu distinguer les effets privilégiés des métaux : cobalt (redox versatile dépendant des conditions de synthèse), fer (effet réducteur) et manganèse (effet oxydant) par des analyses structurales fines. Bien sûr les interactions métal-métal modulables influent sur les propriétés électroniques et magnétiques de ces solides. A ces effets redox, s’ajoutent des effets stériques, qui varient suivant la nature de l’anion X, conduisant à une sous-stœchiométrie sur l'halogène et à une délocalisation spatiale variable dépendant du rayon ionique. Finalement l’ensemble du travail réalisé sur ces phases conduit à un certain nombre de composés inédits, associés à des structures originales ou inattendues. Finalement, l'insertion, non volontaire dans un premier temps, de groupements carbonates (CO3)2- dans différents types structuraux a également été étudiée. / This work concerns the synthesis, structural study and physico-chemical characterization of structural systems derived from the 6H and 10H hexagonal perovskites polytypes, formulated BaMX0.2-xO3-δ (M = Co, Fe, Mn, X = F, Cl, Br). The understanding of the stable structural types depending on the substitution on the M and X sites available in the structure was undertaken through analysis of the sub-stoichiometry of the anionic network. It appears that the reduction of the metal is accompanied by the stabilization of polytypes including oligomers of three face–sharing octahedra, while oxidation will tend to stabilize structures with longer sub-units. We have been able to distinguish trends of particular metals by detailed structural analysis, e.g. cobalt (versatile redox - depending on the synthesis conditions), iron (reducing effect) and manganese (oxidizing effect). Of course the flexible metal-metal interactions affect the electronic and magnetic properties of these solids. In addition to the redox changes, steric effects appear, depending on the nature of the X anion, leading to a sub-stoichiometry of the halogen and variable ionic radius-dependent spatial delocalization. Finally, the work on these phases led to a number of novel compounds, associated with original structures. Finally, the insertion, non-voluntary at first, of carbonates ((CO3)2-) groups in different structural types, was also studied.
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K-théorie pour les C*-algèbres de pavages de Penrose hyperboliques / K-theory of hyperbolic Tilings associated C*-algebrasCollin, Pierre-Henry 19 December 2018 (has links)
Etant donnée une substitution de dimension 1, notée $\sigma$, nous pouvons définir l'enveloppe $\Omega_\sigma$ formant un système dynamique $(\Omega_\sigma, \R)$ où l'action de $\R$ sur les pavages est donnée par les translations. Si la substitution est primitive alors nous pouvons construire un pavage $P$ du demi-plan de Poincaré $\mathbb H_2 $ muni de sa métrique $\frac{\mathrm d x + \mathrm d y}{y^2}$. De manière analogue nous pouvons construire des enveloppes pour les actions de $N= \{ \mathbb{H}_2 \to \mathbb{H}_2, z \mapsto z +t, t\in \R\}$ et $G = \{ \mathbb{H}_2 \to \mathbb{H}_2, z \mapsto a z +b,(a,b) \in \R_+ ^* \times \R\}$ que l'on notera respectivement $X_P ^N$ et $X_{P(c)}^G$ (où $P(c)$ est le pavage colorié ligne à ligne pour rendre l'action de $G$ libre).\par En utilisant la notion de $C^* $-algèbre de groupoïde ainsi que les résultats obtenus dans l'article de Ian Putnam et Jared Anderson et via l'isomorphisme issu de l'équivalence Morita entre $C((\Xi \times \R)/\As)$ et $C(\Xi) \rtimes \Z$, nous pouvons donner la description de la $C^*$-algèbre de l'enveloppe du pavage hyperbolique en termes de générateurs et relations. Nous terminons par la description des générateurs de la $K$-théorie de $C(X_{P(c)}^G) \rtimes G.$ pour les substitutions de Fibonacci, Thue-Morse et Tribonacci / Given a one dimensional substitution $\sigma$, one can define the continuous hull $\Omega_\sigma$ for the $\R$-action given by translations and so we obtain a dynamical system $(\Omega_\sigma,\sigma)$. If the substitution we choose is primitive, then we can construct an hyperbolic tiling on Poincaré's half-plane equiped with its standard metric $\frac{\mathrm d x +\mathrm d y}{y^2}$. By analogy of the standard case, we can define two continuous hulls, denoted $X_P ^ N $ and $X_{P(c)}^G$, where $P(c)$ is a colored tiling (in such fashion that the action of $G$ is free), and the groups are denoted respectively $N= \{ \mathbb{H}_2 \to \mathbb{H}_2, z \mapsto z +t, t\in \R\}$ and $G = \{ \mathbb{H}_2 \to \mathbb{H}_2, z \mapsto a z +b,(a,b) \in \R_+ ^* \times \R\}$.\par Using Jean Renault's construction of the reduced $C^*$-algebra of a groupoid , the results of Ian Putnam and Jared Anderson and the Morita equivalence between $C((\Xi\times \R)/\As)$ and $C(\Xi) \rtimes \Z$, we describe the $C^*$-algebra of the hyperbolic tiling using generators and relations. Finally we obtain for the Fibonacci, Thue-Morse and Tribonacci substitutions the full description of the generators of $K_* (C(X_{P(c)}^G ) \rtimes G)$
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Recherche de nouveaux solvants éco-compatibles de substitution dans le cadre de REACH / New eco-friendly solvents for REACH substitutionSandjong Kuigwa, Lyonnelle 11 October 2013 (has links)
Notre étude est axée sur la recherche de nouveaux solvants éco-compatibles de substitution dans le cadre de la directive européenne REACH. Plus particulièrement, le but du projet est de substituer les solvants toxiques tels que la N-méthylpyrrolidone (NMP), le crésol et le phénol utilisés dans l'industrie des vernis d'émaillage par des solvants de moindre toxicité qui permettent de synthétiser ces vernis dans ces solvants tout en conservant les mêmes propriétés. Pour la synthèse de leur vernis d'émaillage qui est par exemple utilisé pour le revêtement des fils de cuivre, l'entreprise IVA utilise en grande quantité la NMP (CMR-18), le phénol et le crésol (toxique, irritant, corrosif..). Lors du processus de revêtement, les solvants contenus dans le vernis sont brûlés. Pour substituer ces solvants, nous allons dans un premier temps, étudier le mécanisme de polymérisation et ainsi comprendre le rôle des solvants impliqués. Ensuite, nous allons procéder à la caractérisation des polymères constituants les vernis (les polyesterimides et les polyamide-imides) en synthétisant des « authentiques » qui ont été caractérisés -entre autre- par analyse infrarouge. En fin, nous effectuerons un criblage de différents solvants « moins toxiques » afin de réaliser la synthèse des polymères dans ce(s) nouveau(x) solvant(s). Les solvants utilisés seront soit commerciaux, soit synthétisés à partir de la biomasse. Lorsque les vernis d'émaillage non toxiques seront obtenus dans un ou plusieurs nouveaux solvants de moindre toxicité, nous évaluerons leurs propriétés d'application / Our study is focused on the search of new solvents eco-compatible alternative development in the framework of the European directive REACH. More particularly, the aim of the project is to substitute the toxic solvents such as N-methyl pyrrolidone (NMP), the cresol and phenol used in the industry of the varnishes of enamelling by solvents of lesser toxicity which enable you to synthesize these varnishes in these solvents while maintaining the same properties. For the synthesis of their varnish of enameling which for example is used for the coating of the copper wires, company IVA uses in great quantity NMP (CMR-1B), phenol and cresol (toxic, irritant, corrossive….). During the process of coating, the solvents contained in varnish are flaring. To substitute these solvents, we will in a first time, study the mechanism of polymerization and thus understand the role of solvents involved. Then, we will proceed to the characterization of the polymer constituents the varnish (the poly (esterimide) s and the polyamide-imides) by synthesizing "authentic" which were characterized ideally by infrared analysis. Finally, we will conduct a screening of different solvents "less toxic" in order to achieve the synthesis of polymers in this/these new solvent(s). The solvents used will be either commercial, or synthesized from biomass. When the varnish of enameling non toxic will be obtained in one or several new solvents of lesser toxicity, we will assess their application properties
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Essai sur l'histoire des substitutions : du IXe au XVe siècle dans la pratique et la doctrine spécialement en France méridionale /Petitjean, Michel. January 1975 (has links)
Thèse--Droit--Dijon, 1971. / Bibliogr. p. 11-47.
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