Kinetics and coverage dependent reaction mechanisms of the copper atomic layer deposition from copper dimethylamino-2-propoxide and diethylzinc

Atomic layer deposition (ALD) has been recognized as a promising method to deposit conformal and uniform thin film of copper for future electronic devices. However, many aspects of the reaction mechanism and the surface chemistry of copper ALD remain unclear. In this paper, we employ plane wave density functional theory (DFT) to study the transmetalation ALD reaction of copper dimethylamino-2-propoxide [Cu(dmap)2] and diethylzinc [Et2Zn] that was realized experimentally by Lee et al. [ Angew. Chem., Int. Ed. 2009, 48, 4536−4539]. We find that the Cu(dmap)2 molecule adsorbs and dissociates through the scission of one or two Cu–O bonds into surface-bound dmap and Cu(dmap) fragments during the copper pulse. As Et2Zn adsorbs on the surface covered with Cu(dmap) and dmap fragments, butane formation and desorption was found to be facilitated by the surrounding ligands, which leads to one reaction mechanism, while the migration of ethyl groups to the surface leads to another reaction mechanism. During both reaction mechanisms, ligand diffusion and reordering are generally endothermic processes, which may result in residual ligands blocking the surface sites at the end of the Et2Zn pulse, and in residual Zn being reduced and incorporated as an impurity. We also find that the nearby ligands play a cooperative role in lowering the activation energy for formation and desorption of byproducts, which explains the advantage of using organometallic precursors and reducing agents in Cu ALD. The ALD growth rate estimated for the mechanism is consistent with the experimental value of 0.2 Å/cycle. The proposed reaction mechanisms provide insight into ALD processes for copper and other transition metals.

Sasakian quiver gauge theories and instantons on cones over lens 5-spaces

We consider SU(3)-equivariant dimensional reduction of Yang Mills theory over certain cyclic orbifolds of the 5-sphere which are Sasaki-Einstein manifolds. We obtain new quiver gauge theories extending those induced via reduction over the leaf spaces of the characteristic foliation of the Sasaki-Einstein structure, which are projective planes. We describe the Higgs branches of these quiver gauge theories as moduli spaces of spherically symmetric instantons which are SU(3)-equivariant solutions to the Hermitian Yang-Mills equations on the associated Calabi-Yau cones, and further compare them to moduli spaces of translationally-invariant instantons on the cones. We provide an explicit unified construction of these moduli spaces as Kahler quotients and show that they have the same cyclic orbifold singularities as the cones over the lens 5-spaces. (C) 2015 The Authors. Published by Elsevier B.V.

Calculation of electric field strengths at a sharp edge

Sharp edges were first used for field ionisation mass spectrometry by Beckey. Although Cross and Robertson found that etched metal foils were more effective than razor blades for field ionisation, blades are very convenient for determination of field ionisation mass spectra, as reported by Robertson and Viney. The electric field at the vertex of a sharp edge can be calculated by the method of the conformal transformation. Here we give some equations for the field deduced with the assumption that the edge surface can be approximated by a hyperbola. We also compare two hyperbolae with radii of curvature at the vertex of 500 Angstrom and 1000 Angstrom with the profile of a commercial carbon-steel razor blade.

Electric field strengths and ion trajectories in sharp-edge field ionization sources

On the presumption that a sharp edge may be represented by a hyperbola, a conformal transformation method is used to derive electric field equations for a sharp edge suspended above a flat plate. A further transformation is then introduced to give electric field components for a sharp edge suspended above a thin slit. Expressions are deduced for the field strength at the vertex of the edge in both arrangements. The calculated electric field components are used to compute ion trajectories in the simple edge/flat-plate case. The results are considered in relation to future study of ion focusing and unimolecular decomposition of ions in field ionization mass spectrometers.

Advanced Adhesion Strength Testing Methods of Thin Film Multilayers in Electronic Packaging Systems

With the continued miniaturization and increasing performance of electronic devices, new technical challenges have arisen. One such issue is delamination occurring at critical interfaces inside the device. This major reliability issue can occur during the manufacturing process or during normal use of the device. Proper evaluation of the adhesion strength of critical interfaces early in the product development cycle can help reduce reliability issues and time-to-market of the product. However, conventional adhesion strength testing is inherently limited in the face of package miniaturization, which brings about further technical challenges to quantify design integrity and reliability. Although there are many different interfaces in today's advanced electronic packages, they can be generalized into two main categories: 1) rigid to rigid connections with a thin flexible polymeric layer in between, or 2) a thin film membrane on a rigid structure. Knowing that every technique has its own advantages and disadvantages, multiple testing methods must be enhanced and developed to be able to accommodate all the interfaces encountered for emerging electronic packaging technologies. For evaluating the adhesion strength of high adhesion strength interfaces in thin multilayer structures a novel adhesion test configuration called “single cantilever adhesion test (SCAT)” is proposed and implemented for an epoxy molding compound (EMC) and photo solder resist (PSR) interface. The test method is then shown to be capable of comparing and selecting the stronger of two potential EMC/PSR material sets. Additionally, a theoretical approach for establishing the applicable testing domain for a four-point bending test method was presented. For evaluating polymeric films on rigid substrates, major testing challenges are encountered for reducing testing scatter and for factoring in the potentially degrading effect of environmental conditioning on the material properties of the film. An advanced blister test with predefined area test method was developed that considers an elasto-plastic analytical solution and implemented for a conformal coating used to prevent tin whisker growth. The advanced blister testing with predefined area test method was then extended by employing a numerical method for evaluating the adhesion strength when the polymer’s film properties are unknown.

N=4 supersymmetric AdS(5) vacua and their moduli spaces

We classify the N = 4 supersymmetric AdS(5) backgrounds that arise as solutions of five-dimensional N = 4 gauged supergravity. We express our results in terms of the allowed embedding tensor components and identify the structure of the associated gauge groups. We show that the moduli space of these AdS vacua is of the form SU(1, m)/ (U(1) x SU(m)) and discuss our results regarding holographically dual N = 2 SCFTs and their conformal manifolds.

The tetrahexahedric angular Calogero model

The spherical reduction of the rational Calogero model (of type A n−1 and after removing the center of mass) is considered as a maximally superintegrable quantum system, which describes a particle on the (n−2)-sphere subject to a very particular potential. We present a detailed analysis of the simplest non-separable case, n=4, whose potential is singular at the edges of a spherical tetrahexahedron. A complete set of independent conserved charges and of Hamiltonian intertwiners is constructed, and their algebra is elucidated. They arise from the ring of polynomials in Dunkl-deformed angular momenta, by classifying the subspaces invariant and antiinvariant under all Weyl reflections, respectively.

The D(D-3)-anyon chain: integrable boundary conditions and excitation spectra

Chains of interacting non-Abelian anyons with local interactions invariant under the action of the Drinfeld double of the dihedral group D-3 are constructed. Formulated as a spin chain the Hamiltonians are generated from commuting transfer matrices of an integrable vertex model for periodic and braided as well as open boundaries. A different anyonic model with the same local Hamiltonian is obtained within the fusion path formulation. This model is shown to be related to an integrable fusion interaction round the face model. Bulk and surface properties of the anyon chain are computed from the Bethe equations for the spin chain. The low-energy effective theories and operator content of the models (in both the spin chain and fusion path formulation) are identified from analytical and numerical studies of the finite-size spectra. For all boundary conditions considered the continuum theory is found to be a product of two conformal field theories. Depending on the coupling constants the factors can be a Z(4) parafermion or a M-(5,M-6) minimal model.

Strong shift equivalence, algebraic K-theory, and isolating zero-dimensional dynamics on manifolds

We study the relations of shift equivalence and strong shift equivalence for matrices over a ring $\mathcal{R}$, and establish a connection between these relations and algebraic K-theory. We utilize this connection to obtain results in two areas where the shift and strong shift equivalence relations play an important role: the study of finite group extensions of shifts of finite type, and the Generalized Spectral Conjectures of Boyle and Handelman for nonnegative matrices over subrings of the real numbers. We show the refinement of the shift equivalence class of a matrix $A$ over a ring $\mathcal{R}$ by strong shift equivalence classes over the ring is classified by a quotient $NK_{1}(\mathcal{R}) / E(A,\mathcal{R})$ of the algebraic K-group $NK_{1}(\calR)$. We use the K-theory of non-commutative localizations to show that in certain cases the subgroup $E(A,\mathcal{R})$ must vanish, including the case $A$ is invertible over $\mathcal{R}$. We use the K-theory connection to clarify the structure of algebraic invariants for finite group extensions of shifts of finite type. In particular, we give a strong negative answer to a question of Parry, who asked whether the dynamical zeta function determines up to finitely many topological conjugacy classes the extensions by $G$ of a fixed mixing shift of finite type. We apply the K-theory connection to prove the equivalence of a strong and weak form of the Generalized Spectral Conjecture of Boyle and Handelman for primitive matrices over subrings of $\mathbb{R}$. We construct explicit matrices whose class in the algebraic K-group $NK_{1}(\mathcal{R})$ is non-zero for certain rings $\mathcal{R}$ motivated by applications. We study the possible dynamics of the restriction of a homeomorphism of a compact manifold to an isolated zero-dimensional set. We prove that for $n \ge 3$ every compact zero-dimensional system can arise as an isolated invariant set for a homeomorphism of a compact $n$-manifold. In dimension two, we provide obstructions and examples.

Alternating surgeries

This thesis is concerned with the question of when the double branched cover of an alternating knot can arise by Dehn surgery on a knot in S^3. We approach this problem using a surgery obstruction, first developed by Greene, which combines Donaldson's Diagonalization Theorem with the $d$-invariants of Ozsvath and Szabo's Heegaard Floer homology. This obstruction shows that if the double branched cover of an alternating knot or link L arises by surgery on S^3, then for any alternating diagram the lattice associated to the Goeritz matrix takes the form of a changemaker lattice. By analyzing the structure of changemaker lattices, we show that the double branched cover of L arises by non-integer surgery on S^3 if and only if L has an alternating diagram which can be obtained by rational tangle replacement on an almost-alternating diagram of the unknot. When one considers half-integer surgery the resulting tangle replacement is simply a crossing change. This allows us to show that an alternating knot has unknotting number one if and only if it has an unknotting crossing in every alternating diagram. These techniques also produce several other interesting results: they have applications to characterizing slopes of torus knots; they produce a new proof for a theorem of Tsukamoto on the structure of almost-alternating diagrams of the unknot; and they provide several bounds on surgeries producing the double branched covers of alternating knots which are direct generalizations of results previously known for lens space surgeries. Here, a rational number p/q is said to be characterizing slope for K in S^3 if the oriented homeomorphism type of the manifold obtained by p/q-surgery on K determines K uniquely. The thesis begins with an exposition of the changemaker surgery obstruction, giving an amalgamation of results due to Gibbons, Greene and the author. It then gives background material on alternating knots and changemaker lattices. The latter part of the thesis is then taken up with the applications of this theory.

L'évaluation de l'autonomie fonctionnelle des personnes âgées : contribution de la didactique professionnelle à la formation des travailleuses et travailleurs sociaux au Québec

Résumé : Le vieillissement démographique est statistiquement indiscutable au Québec. Ce singulier trompeur masque les différentes manières de vieillir. Pour ceux qui ne parviennent pas à vieillir en santé, les solidarités familiales, comme les solidarités institutionnelles, c’est à dire publiques viennent en principe compenser ce qu’il est convenu de désigner de perte d’autonomie. Les politiques de santé publique au Québec organisent les services de soutien à domicile sous condition d’avoir estimé la situation de la personne avec l’outil d’évaluation multiclientèle (OEMC). Il est en usage dans l’ensemble du réseau de la santé et des services sociaux, et utilisé par les professionnels dont les travailleuses et les travailleurs sociaux (TS). Or, la gérontologie est peu soutenue dans la formation initiale des TS. Nous nous sommes interrogée sur les savoirs mobilisés par les TS quand ils évaluent. S’agissant des savoirs inscrits dans la pratique, nous avons orienté la recherche dans les théories de l’activité, la didactique professionnelle et le cadre conceptuel de la médiation. Nous avons étudié l’activité de professionnels en travail social expérimentés afin d’identifier certains des savoirs mobilisés pour les rendre disponibles à la formation des étudiant (e)s en travail social au Québec. Cent-cinquante heures d’observations et vingt-deux entretiens individuels et collectifs ont été réalisés avec des intervenants volontaires du service de soutien à domicile. Les résultats préliminaires de la recherche ont été présentés lors de groupes de discussion avec les TS ayant participé à la recherche, puis avec des enseignants en travail social. Nos résultats permettent de décrire les procédures de l’évaluation dans l’organisation du service d’aide à domicile et d’en différencier le processus de l’activité par laquelle le TS évalue l’autonomie fonctionnelle de la personne. Nous constatons que les savoirs mobilisés par les TS reposent premièrement sur une connaissance fine du territoire, de l’outil d’évaluation et des institutions. Un deuxième registre de savoir concerne la conceptualisation de l’autonomie fonctionnelle par l’outil OEMC comme objet et domaine d’intervention des TS. Enfin, un troisième registre se réfère aux savoirs mobilisés pour entrer en relation avec les personnes âgées, avec leur entourage. Or, ces trois registres de savoir n’apparaissent pas dans le discours des TS et résultent de notre propre analyse sur leur pratique. L’évaluation de l’autonomie fonctionnelle analysée par le concept de médiation est révélatrice du rapport aux savoirs du TS. S’agissant de savoirs de la pratique, nous constatons que leur classification entre les catégories usuelles de savoirs théoriques ou pratiques était inopérante. Nous empruntons le vocabulaire de la didactique professionnelle : celui des invariants opératoires reliés à l’autonomie fonctionnelle et celui des schèmes d’activité reliés à l’activité d’évaluation. C’est ainsi que nous avons identifié deux moments dans l’évaluation. Le premier assemble la collecte des informations et l’analyse des données. L’autonomie fonctionnelle se décline dans des conditions d’existence de la personne sur l’axe allant de la mobilité à la cognition avec comme balises d’intervention la sécurité et l’intégrité de la personne. Dans ce processus itératif, le TS identifie avec la personne ce qui nuit à son quotidien. L’évaluation formule comment résoudre cette incidence, comment la perte d’autonomie pourrait être compensée. La collecte d’information et le raisonnement du TS est alors un mouvement itératif, les deux éléments du processus sont liés et en continu. Le second moment de l’évaluation apparait si, dans le processus itératif, le TS perçoit une dissonance. Il est essentiel d’en identifier la nature pour la prendre en compte et maintenir la finalité de l’activité qui consiste à évaluer l’autonomie fonctionnelle à des fins compensatrices. Le TS doit identifier l’objet de la dissonance pour pouvoir cerner avec la personne le besoin inhérent à la perte d’autonomie et envisager d’y remédier. La prise en compte de cette dissonance vient ralentir le déroulement de l’activité. Le raisonnement qui, jusque-là, était relié à la collecte d’informations s’en dissocie pour analyser ce qui vient faire obstacle à l’activité d’évaluation à partir de la situation. Les composantes qui génèrent la dissonance paraissent reliées à la quotidienneté, aux conditions de vie à domicile de la personne (cohérence/incohérence, refus de services, autonégligence, maltraitance, agressivité). La dissonance génère une activité plus complexe pour évaluer la situation. L’autonomie fonctionnelle se décline toujours sur l’axe mobilité/cognition avec comme balises d’intervention la sécurité et l’intégrité de la personne. Or, pour ce faire, les TS raisonnent selon trois schèmes. Dans les situations où, pour décider de la suite du dossier, il faut en référer à une norme (de service, de profession, etc.) le raisonnement est déontologique. Il est aussi des situations où le TS agit au regard de valeurs et de représentations qui relèvent de sa sphère personnelle. Nous désignons ce raisonnement d’instinctuel. Enfin, le TS peut naviguer entre ces deux orientations et choisir la voie du raisonnement clinique que nous qualifions d’éthique et se rapproche alors des pratiques prudentielles qui sont marquées par l’incertitude.

Hydrologic unit map--1974, State of New Jersey.

Scale 1:500,000; 1 in. equals approx. 8 miles.

State of New Jersey /

Scale 1:500,000; 1 in. equals approx. 8 miles.

State of New Jersey /

Scale 1:500,000; 1 in. equals approx. 8 miles.

The Riemann sphere in GeoGebra

The stereographic projection is a bijective smooth map which allows us to think the sphere as the extended complex plane. Among its properties it should be emphasized the remarkable property of being angle conformal that is, it is an angle measure preserving map. Unfortunately, this projection map does not preserve areas. Besides being conformal it has also the property of projecting spherical circles in either circles or straight lines in the plane This type of projection maps seems to have been known since ancient times by Hipparchus (150 BC), being Ptolemy (AD 140) who, in his work entitled "The Planisphaerium", provided a detailed description of such a map. Nonetheless, it is worthwhile to mention that the property of the invariance of angle measure has only been established much later, in the seventeenth century, by Thomas Harriot. In fact, it was exactly in that century that the Jesuit François d’Aguilon introduced the terminology "stereographic projection" for this type of maps, which remained up to our days. Here, we shall show how we create in GeoGebra, the PRiemannz tool and its potential concerning the visualization and analysis of the properties of the stereographic projection, in addition to the viewing of the amazing relations between Möbius Transformations and stereographic projections.