93 research outputs found
CEDRIC J. POWELL
No full textCEDRIC J. POWELL
Inducted: 2010
Citation:
For exceptional scientific and organizational work in establishing the physical basis (and infrastructure) for electron spectroscopies of solids, especially as applied to quantitative surface analysis and surface standards
Tenure: 1962-2006
Birth: 1935; Perth, Australia
Education:
University of Western Australia, BS (Physics), 1956
University of Western Australia, PhD (Physics), 1962
Positions held:
Physicist, Atomic Physics and Optical Physics Divisions, Institute for Basic Standards, 1962-1978
Chief, Surface Science Division, Center for Chemical Physics, 1978-1991
Leader, Surface Spectroscopies and Thin Films Group, Surface and Microanalysis Science Division, 1991-1994
NIST Fellow, Surface and Microanalysis Science Division, 1994-2006
NIST Scientist Emeritus, Surface and Microanalysis Science Division, 2007-Present
Honors:
US Department of Commerce Silver Medal (1983) and Gold Medal (1986)Award of Merit, American Society for Testing and Materials (ASTM) (1988)
Riviere Prize, UK ESCA Users Group (1992)
Creation of Cedric Powell Award by ASTM Committee E-42 on Surface Analysis (1993)
Creation of Powell Prize by the Surface Analysis Society of Japan (1995)
Albert Nerken Award, American Vacuum Society (2001)
Technology Prize, International Union of Vacuum Science, Technique, and Applications (2007)
Memberships:
American Physical Society, American Vacuum Society, American Assn. for the Advancement of Science
ASTM Committee E-42 on Surface Analysis, chairman (1980-85)
Board of Trustees, Gordon Research Conferences (1982-88), chairman (1985-86)
Board of Directors, American Vacuum Society (1988-89)
ISO Technical Committee 201 on Surface Chemical Analysis, chairman (1992-98)
Publications:
Co-editor of 3 books, co-author of 5 NIST databases, and an author of more than 240 publications including:
Powell, C. J., “Contrasting Valence-Band Auger-Electron Spectra for Silver and Aluminum”, Phys. Rev. Letters 30, 1179 (1973)
Powell, C. J., “Attenuation Lengths of Low-energy Electrons in Solids”, Surface Science 44, 29 (1974)
Powell, C. J., “Cross Sections for Ionization of Inner-shell Electrons by Electrons”, Rev. Mod. Phys. 48, 33 (1976)
Powell, C. J. and Seah, M. P., “Precision, Accuracy, and Uncertainty in Quantitative Surface Analyses by Auger-Electron Spectroscopy and X-ray Photoelectron Spectroscopy”, J. Vac. Sci. Technol. A 8, 735 (1990)
Tanuma, S., Powell, C. J., and Penn, D. R., ""Calculations of Electron Inelastic Mean Free Paths. II. Data for 27 Elements over the 50-2000 eV Range,"" Surface and Interface Analysis 17, 911 (1991)
Powell, C. J. and Jablonski, A., “Evaluation of Measured and Calculated Electron Inelastic Mean Free Paths Near Solid Surfaces,” J. Phys. Chem. Ref. Data 28, 19 (1999
Recommended from our members
Dr. J. Don Vann Manuscript Collection, 1963-2007
No full textPhotograph of (L-R) Dr. J. Don Vann, Cedric Charles Dickens, the grandson of author Charles Dickens, and Dolores Vann. They are standing in front of the door to Charles Dickens' home which has been made into a museum of the author's works and life. The prices for admission are listed on a plaque beside the door
Recommended from our members
Dr. J. Don Vann Manuscript Collection, 1963-2007
No full textPhotograph of Cedric Charles Dickens (red tie), the great-grandson of author Charles Dickens, and other men in a bar. Small signs and decorations are at the top of the bar and one reading "No service this end" is in front of them. A full pint is on the bar-top and the bar-tender is handing a fresh one over
Uncertainty and the Disappearance of International Credit
Full text linkWe show that increased uncertainty about the size of an emerging market's external debt has a nonlinear and potentially large adverse effect on the supply of international credit offered to them. We also show that if international creditors are first- order risk averse, attaching greater weight to utility derived from bad outcomes than from good ones, a moderate increase in uncertainty about debt overhang or about other relevant factors affecting repayment prospects-- can cause the supply of credit to dry up completely. We therefore offer one possible explanation for why emerging markets may find themselves suddenly cut off from international capital markets.
The ‘Galilean Style in Science’ and the Inconsistency of Linguistic Theorising
No full textChomsky’s principle of epistemological tolerance says that in theoretical linguistics contradictions between the data and the hypotheses may be temporarily tolerated in order to protect the explanatory power of the theory. The paper raises the following problem: What kinds of contradictions may be tolerated between the data and the hypotheses in theoretical linguistics? First a model of paraconsistent logic is introduced which differentiates between week and strong contradiction. As a second step, a case study is carried out which exemplifies that the principle of epistemological tolerance may be interpreted as the tolerance of week contradiction. The third step of the argumentation focuses on another case study which exemplifies that the principle of epistemological tolerance must not be interpreted as the tolerance of strong contradiction. The reason for the latter insight is the unreliability and the uncertainty of introspective data. From this finding the author draws the conclusion that it is the integration of different data types that may lead to the improvement of current theoretical linguistics and that the integration of different data types requires a novel methodology which, for the time being, is not available
Beyond Lesson Studies and Design Experiments: Using theoretical tools in practice and finding out how they work
Full text linkThis paper aims to illustrate how fruitful insights into the link between school teaching practice and student learning outcomes can be theoretically grounded by the variation theory from the field of phenomenography; and from this framework demonstrate how a 'pedagogy of awareness' can be implemented in the classroom. In this study, five teachers and 162 students at Primary Four level of school education in Hong Kong participated and the practice of the 'learning study' was adopted. By comparing the results of pre- and posttests, a significant gain was observed in the students learning outcomes.
Photoacoustic raster scan imaging using an optomechanical ultrasound sensor in silicon photonics
Full text linkPhotoacoustic tomography defines new challenges for ultrasound detection compared to ultrasonography. To address these challenges, a sensitive, small, scalable, and broadband optomechanical ultrasound sensor (OMUS) has been developed. The OMUS is an on-chip optical ultrasound sensor, using optical interferometric ultrasound detection. It consists of an acoustic membrane on top of an optical ring resonator that modulates the optical ring resonance with high efficiency enabled by an innovative optomechanical waveguide. Raster scanning photoacoustic tomography has been demonstrated with a single-element OMUS. Based on performance and form factor, the OMUS combined with passive optical multiplexing may enable new applications in photoacoustic imaging.Optical Technologie
Exploring conformational equilibria of a heterodimeric ABC transporter
Full text linkABC exporters pump substrates across the membrane by coupling ATP-driven
movements of nucleotide binding domains (NBDs) to the transmembrane domains
(TMDs), which switch between inward- and outward-facing (IF, OF) orientations.
DEER measurements on the heterodimeric ABC exporter TM287/288 from Thermotoga
maritima, which contains a non-canonical ATP binding site, revealed that in
the presence of nucleotides the transporter exists in an IF/OF equilibrium.
While ATP binding was sufficient to partially populate the OF state,
nucleotide trapping in the pre- or post-hydrolytic state was required for a
pronounced conformational shift. At physiologically high temperatures and in
the absence of nucleotides, the NBDs disengage asymmetrically while the
conformation of the TMDs remains unchanged. Nucleotide binding at the
degenerate ATP site prevents complete NBD separation, a molecular feature
differentiating heterodimeric from homodimeric ABC exporters. Our data suggest
hydrolysis-independent closure of the NBD dimer, which is further stabilized
as the consensus site nucleotide is committed to hydrolysis
Sensitive optomechanical ultrasound sensor in a silicon photonic chip towards single-shot photoacoustic imaging with an ultrasound sensor matrix
No full textWe propose a new opto-mechanical ultrasound sensor (OMUS) enabled by an innovative silicon photonics waveguide. We present experimental results up to 30 MHz, a 10-sensor array proof-of-concept and our latest findings.Dynamics of Micro and Nano System
Intertextual Episodes in Lectures: A Classification from the Perspective of Incidental Learning from Reading
No full textIn a parallel language environment it is important that teaching takes account of both the languages students are expected to work in. Lectures in the mother tongue need to offer access to textbooks in English and encouragement to read. This paper describes a preliminary study for an investigation of the extent to which they actually do so. A corpus of lectures in English for mainly L1 English students (from BASE and MICASE) was examined for the types of reference to reading which occur, classifi ed by their potential usefulness for access and encouragement. Such references were called ‘intertextual episodes’. Seven preliminary categories of intertextual episode were identifi ed. In some disciplines the text is the topic of the lecture rather than a medium for information on the topic, and this category was not pursued further. In the remaining six the text was a medium for information about the topic. Three of them involved management, of texts by the lecturer her/himself, of student writing, or of student reading. The remaining three involved reference to the content of the text either introducing it to students, reporting its content, or, really the most interesting category, relativizing it and thus potentially encouraging critical reading. Straightforward reporting that certain content was in the text at a certain point was the most common type, followed by management of student reading. Relativization was relatively infrequent. The exercise has provided us with categories which can be used for an experimental phase where the effect of different types of reference can be tested, and for observation of the references actually used in L1 lectures in a parallel-language environment
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