Evidence for Amphoteric Behavior of Ru on CdTe Surfaces

Modification of large grain p-CdTe by Ru is shown to reduce the sub-band-gap response and increase minority-carrier diffusion length from 0.67 to 0.92 µm. Contact potential difference (CPD) measurements on n- and p-CdTe show shifts in surface Fermi level in opposite directions corresponding to increase in barrier height in each case. The amphoteric nature of Ru on CdTe surfaces depending on conductivity type is thus inferred. The magnitudes of the changes in CPD are approximately equal to the increase of open circuit voltage V∞ observed in photoelectro-chemical cells

Almost Contact Lagrangian Submanifolds of Nearly Kaehler 6-Sphere

For a Lagrangian submanifold M of S 6 with nearly Kaehler structure, we provide conditions for a canonically induced almost contact metric structure on M by a unit vector field, to be Sasakian. Assuming M contact metric, we show that it is Sasakian if and only if the second fundamental form annihilates the Reeb vector field ξ, furthermore, if the Sasakian submanifold M is parallel along ξ, then it is the totally geodesic 3-sphere. We conclude with a condition that reduces the normal canonical almost contact metric structure on M to Sasakian or cosymplectic structure

Chemical Control of Male Pre-pupae and Adult Females of Margarodes prieskaensis (Jakubski) (Coccoidea : Margarodidae) on Grapevines

Various contact, fumigant and systemic pesticides were evaluated over three years in a field trial for the control ofmale pre-pupae and adult females of Margarodes prieskaensis on grapevines. Cadusafos at 25 mL/m² gave excellentcontrol of male pre-pupae. Pre-pupae, as well as adult females, were effectively controlled by dichloropropene at15 mL/m², as well as by thiamethoxam at 2.4 mL/m² and 2.0 mL/m² and imidacloprid at 15 mL/m², 3.0 mL/m² and1.5 mL/m². Contact and fumigant applications were made during March and April (beginning of leafdrop), andsystemics during January (one month after harvest). Chlorpyrifos, furfural, fenamiphos, carbofuran and terbufoswere found to be ineffective for the control of M. prieskaensis

Global Hamiltonian dynamics on singular symplectic manifolds

In this thesis, we study the Reeb and Hamiltonian dynamics on singular symplectic and contact manifolds. Those structures are motivated by singularities coming from classical mechanics and fluid dynamics. We start by studying generalized contact structures where the non-integrability condition fails on a hypersurface, the critical hypersurface. Those structures, called $b$-contact structures, arise from hypersurfaces in $b$-symplectic manifolds that have been previously studied extensively in the past. Formerly, this odd-dimensional counterpart to $b$-symplectic geometry has been neglected in the existing vast literature. Examples are given and local normal forms are proved. The local geometry of those manifolds is examined using the language of Jacobi manifolds, which provides an adequate set-up and leads to understanding the geometric structure on the critical hypersurface. We further consider other types of singularities in contact geometry, as for instance higher order singularities, called $b^m$-contact forms, or singularities of folded type. Obstructions to the existence of those structures are studied and the topology of $b^m$-contact manifolds is related to the existence of convex contact hypersurfaces and further relations to smooth contact structures are described using the desingularization technique. We continue examining the dynamical properties of the Reeb vector field associated to a given $b^m$-contact form. The relation of those structures to celestial mechanics underlines the relevance for existence results of periodic orbits of the Hamiltonian vector field in the $b^m$-symplectic setting and Reeb vector fields for $b^m$-contact manifolds. In this light, we prove that in dimension $3$, there are always infinitely many periodic Reeb orbits on the critical surface, but describe examples without periodic orbits away from it in any dimension. We prove that there are traps for this vector field and discuss possible extensions to prove the existence of plugs. We will see that in the case of overtwisted disks away from the critical hypersurface and some additional conditions, Weinstein conjecture holds: more precisely there exists either a periodic Reeb orbit away from the critical hypersurface or a $1$-parametric family in the neighbourhood of it. The mentioned results shed new light towards a singular version for this conjecture. The obtained results are applied to the particular case of the restricted planar circular three body problem, where we prove that after the McGehee change, there are infinitely many non-trivial periodic orbits at the manifold at infinity for positive energy values.En esta tesis, estudiamos la dinámica de Reeb y Hamiltoniana en variedades simplécticas y de contacto con singularidades. El estudio de estas variedades está motivado por singularidades que tienen su origen en la mecánica clásica y la dinámica de fluidos. Empezamos estudiando una generalización de las estructuras de contacto, en la cual la condición de no integrabilidad falla en una hipersuperficie, llamada la hipersuperficie crítica. Estas estructuras geométricas, llamadas estructuras de $b$-contacto, surgen de hipersuperficies en variedades $b$-simplécticas, estudiadas en el pasado. Hasta el momento, este equivalente de dimensión impar de la geometría $b$-simpléctica ha sido desatendido en la literatura existente. Después de los primeros ejemplos, probamos la existencia de formas locales. Estudiamos la geometría local de estas variedades usando el lenguaje de variedades de Jacobi, que resultan ser técnicas adecuadas para entender la estructura geométrica en la hipersuperficie crítica. Consideramos también singularidades de orden superior, formas de $b^m$-contacto, y singularidades de tipo folded. Continuamos con el estudio de las obstrucciones a la existencia de estas estructuras y relacionamos la topología de variedades de $b^m$-contacto con la existencia de hipersuperficies convexas. Describimos relaciones entre formas de $b^m$-contacto y formas de contacto diferenciables usando técnicas de desingularización. Examinamos las propiedades del campo de Reeb asociado a una forma de $b^m$-contacto dada. La relación de estas estructuras con la mecánica celeste pone en relieve la importancia del estudio de órbitas periódicas de este campo vectorial. Comprobamos que, en dimensión $3$, el campo de Reeb en la hipersuperficie crítica admite infinitas órbitas periódicas. Sin embargo, describimos ejemplos sin órbitas periódicas fuera de la hipersuperficie crítica en cualquier dimensión. Comprobamos la existencia de traps y discutimos la posible existencia de plugs. En el caso de un disco \emph{overtwisted} fuera de la hipersuperficie se satisface la conjetura de Weinstein: en concreto, o bien existe una órbita periódica de Reeb fuera de la hipersuperficie de contacto o bien existe una familia de órbitas periódicas en un entorno de la hipersuperficie. Estos resultados sugieren una versión singular de dicha conjetura. Aplicamos los resultados obtenidos al caso del problema de los tres cuerpos restringido circular: comprobamos que después del cambio de coordenadas de McGehee, existen infinitas órbitas periódicas en la variedad en el infinito para valores positivos de la energía.Postprint (published version

Rock Joint Surfaces Measurement and Analysis of Aperture Distribution under Different Normal and Shear Loading Using GIS

Geometry of the rock joint is a governing factor for joint mechanical and hydraulic behavior. A new method of evaluating aperture distribution based on measurement of joint surfaces and three dimensional characteristics of each surface is developed. Artificial joint of granite surfaces are measured,processed, analyzed and three dimensional approaches are carried out for surface characterization. Parameters such as asperity's heights, slope angles, and aspects distribution at micro scale,local concentration of elements and their spatial localization at local scale are determined by Geographic Information System (GIS). Changes of aperture distribution at different normal stresses and various shear displacements are visualized and interpreted. Increasing normal load causes negative changes in aperture frequency distribution which indicates high joint matching. However, increasing shear displacement causes a rapid increase in the aperture and positive changes in the aperture frequency distribution which could be due to unmatching, surface anisotropy and spatial localization of contact points with proceeding shear

Re L (Contact: Domestic Violence; Re V (Contact: Domestic Violence; Re M (Contact:Domestic Violence; Re H (Contact: Domestic Violence)

This is the post-print version of the article