Ed G. Rightor

Bio: Ed G. Rightor is an academic researcher from Dow Chemical Company. The author has contributed to research in topics: Microscope & Beamline. The author has an hindex of 14, co-authored 29 publications receiving 1492 citations. Previous affiliations of Ed G. Rightor include University of Texas System.

Interferometer‐controlled scanning transmission X‐ray microscopes at the Advanced Light Source

Abstract: Two new soft X-ray scanning transmission microscopes located at the Advanced Light Source (ALS) have been designed, built and commissioned. Interferometer control implemented in both microscopes allows the precise measurement of the transverse position of the zone plate relative to the sample. Long-term positional stability and compensation for transverse displacement during translations of the zone plate have been achieved. The interferometer also provides low-distortion orthogonal x, y imaging. Two different control systems have been developed: a digital control system using standard VXI components at beamline 7.0, and a custom feedback system based on PC AT boards at beamline 5.3.2. Both microscopes are diffraction limited with the resolution set by the quality of the zone plates. Periodic features with 30 nm half period can be resolved with a zone plate that has a 40 nm outermost zone width. One microscope is operating at an undulator beamline (7.0), while the other is operating at a novel dedicated bending-magnet beamline (5.3.2), which is designed specifically to illuminate the microscope. The undulator beamline provides count rates of the order of tens of MHz at high-energy resolution with photon energies of up to about 1000 eV. Although the brightness of a bending-magnet source is about four orders of magnitude smaller than that of an undulator source, photon statistics limited operation with intensities in excess of 3 MHz has been achieved at high energy resolution and high spatial resolution. The design and performance of these microscopes are described.

The influence of Pd–Ag catalyst restructuring on the activation energy for ethylene hydrogenation in ethylene–acetylene mixtures

Abstract: Hydrogenation of acetylene–ethylene mixtures was studied on Pd/SiO2 and Pd–Ag/SiO2 under conditions that correspond to “front-end” hydrogenation of acetylene. The presence of excess H2 under “front-end” hydrogenation conditions can lead to thermal runaway due to the exothermic reaction of ethylene and H2. In previous work, we found that activation energy was sensitive to catalyst pretreatment: high temperature treatment in H2 leading to lower apparent activation energy, while pretreatment under oxidizing conditions leading to higher activation energies for ethylene hydrogenation. Since ethylene hydrogenation is a known structure-insensitive reaction, it was puzzling that the apparent activation energy should be so sensitive to catalyst pretreatment. As we show in this work, the presence of co-adsorbed CO (which is present during “front-end” hydrogenation), and changes in the surface structure of Pd–Ag surfaces together modify the apparent activation energy for ethylene hydrogenation. In situ infrared spectroscopy of adsorbed carbon monoxide reveals how the presence of Ag modifies the proportion of bridged and linearly bound CO on Pd/SiO2. High temperature reduction further modifies the ratio of bridged to linear CO on Pd–Ag surfaces. Since CO in bridged form is bound more strongly than linearly bound CO, this shift in adsorption geometry modifies the apparent activation energy for ethylene hydrogenation. This work describes how restructuring of bimetallic Pd–Ag surfaces and the presence of a co-adsorbed CO, work together to alter the reaction behavior of an industrially significant selective hydrogenation reaction.

A scanning transmission x-ray microscope for materials science spectromicroscopy at the advanced light source

Abstract: Design and performance of a scanning transmission x-ray microscope (STXM) at the Advanced Light Source is described This instrument makes use of a high brightness undulator beamline and extends the STXM technique to new areas of research After 25 years of development it is now an operational tool for research in polymer science, environmental chemistry, and magnetic materials

The Design and Analysis of Experiments

Abstract: THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

Aggregation and morphology control enables multiple cases of high-efficiency polymer solar cells.

Abstract: Although the field of polymer solar cell has seen much progress in device performance in the past few years, several limitations are holding back its further development For instance, current high-efficiency (>90%) cells are restricted to material combinations that are based on limited donor polymers and only one specific fullerene acceptor Here we report the achievement of high-performance (efficiencies up to 108%, fill factors up to 77%) thick-film polymer solar cells for multiple polymer:fullerene combinations via the formation of a near-ideal polymer:fullerene morphology that contains highly crystalline yet reasonably small polymer domains This morphology is controlled by the temperature-dependent aggregation behaviour of the donor polymers and is insensitive to the choice of fullerenes The uncovered aggregation and design rules yield three high-efficiency (>10%) donor polymers and will allow further synthetic advances and matching of both the polymer and fullerene materials, potentially leading to significantly improved performance and increased design flexibility

Recycling lower continental crust in the North China craton

Abstract: Foundering of mafic lower continental crust into underlying convecting mantle has been proposed as one means to explain the unusually evolved chemical composition of Earth's continental crust, yet direct evidence of this process has been scarce. Here we report that Late Jurassic high-magnesium andesites, dacites and adakites (siliceous lavas with high strontium and low heavy-rare-earth element and yttrium contents) from the North China craton have chemical and petrographic features consistent with their origin as partial melts of eclogite that subsequently interacted with mantle peridotite. Similar features observed in adakites and some Archaean sodium-rich granitoids of the tonalite-trondhjemite-granodiorite series have been interpreted to result from interaction of slab melts with the mantle wedge. Unlike their arc-related counterparts, however, the Chinese magmas carry inherited Archaean zircons and have neodymium and strontium isotopic compositions overlapping those of eclogite xenoliths derived from the lower crust of the North China craton. Such features cannot be produced by crustal assimilation of slab melts, given the high Mg#, nickel and chromium contents of the lavas. We infer that the Chinese lavas derive from ancient mafic lower crust that foundered into the convecting mantle and subsequently melted and interacted with peridotite. We suggest that lower crustal foundering occurred within the North China craton during the Late Jurassic, and thus provides constraints on the timing of lithosphere removal beneath the North China craton.

Quantitative determination of organic semiconductor microstructure from the molecular to device scale.

Abstract: The authors would like to thank M. Chabinyc, H. Ade, B. Collins, R. Noriega, K. Vandewal, and D. Duong for fruitful discussions in the preparation of this review. Stanford Synchrotron Radiation Lightsource (SSRL) is a national user facility operated by Stanford University on behalf of the U.S. Department of Energy, Office of Basic Energy Sciences. This publication was partially supported by the Center for Advanced Molecular Photovoltaics (Award No. KUS-C1-015-21), made by King Abdullah University of Science and Technology (KAUST).