ExxonMobil

About: ExxonMobil is a company organization based out in Irving, Texas, United States. It is known for research contribution in the topics: Catalysis & Polymer. The organization has 16969 authors who have published 23758 publications receiving 535713 citations. The organization is also known as: Exxon Mobil Corporation & Exxon Mobil Corp..

"Chevron" local layer structure in surface-stabilized ferroelectric smectic-C cells.

Abstract: Mise en evidence de la structure par des etudes de diffusion de rayons X haute resolution d'echantillons minces smectiques C prepares entre deux lames solides par refroidissement a partir de la phase smectique A

Linear viscoelasticity of colloidal hard sphere suspensions near the glass transition.

Abstract: The frequency-dependent viscoelastic shear modulus of concentrated suspensions of colloidal hard spheres is shown to be strongly modified as the volume fraction approaches the glass transition. The elastic or storage component, ${G}^{\ensuremath{'}}$, becomes larger than the viscous or loss component, ${G}^{\ensuremath{'}\ensuremath{'}}$. The frequency dependence of ${G}^{\ensuremath{'}}$ develops a plateau while that of ${G}^{\ensuremath{'}\ensuremath{'}}$ develops a minimum. We propose a physical model to account for these data, using a description of the glasslike behavior based on mode-coupling theory, and a description of the high-frequency behavior based on hydrodynamic flow calculations.

Two new three-dimensional twelve-ring zeolite frameworks of which zeolite beta is a disordered intergrowth

Abstract: Zeolite beta, first described in 19671, is an active catalyst and a useful sorbent1 Sorption1,2 and catalytic data3,4 suggest that the zeolite could possess a three-dimensional 12-ring pore system Such a pore system suggests technological potential similar to that of faujasite framework materials, but until now the structure of this zeolite has eluded determination Powder X-ray diffraction patterns comprise both sharp and broad features, indicative of an extensively faulted structure Here we determine the structure of zeolite beta by high-resolution electron microscopy, electron diffraction and computer-assisted modelling The zeolite is an intergrown hybrid of two distinct but closely related structures Both are constructed from the same centrosymmetrlcal tertiary building unit arranged in layers, and both possess three-dimensional 12-ring pore systems One end member, polymorph A, forms an enantiomorphic pair, with symmetries P4122 and P4322, with a = 124 A and c = 265 A Polymorpb B, in which the stacking of layers alternates in handedness, is achiral with space group P1 ¯, and a ≃ b = 124 A, c = 145 A, α ≃ β = 73°, γ ≃ 90° The high density of stacking faults in zeolite beta materials arises because successive layers must interconnect in either a left- or a right-handed fashion, and both modes of linkage occur with almost equal probability