1,720,977 research outputs found
MATLAB Functions for the Extraction of Refractive Indices from Aerosol Extinction Spectra
Get PDFA set of functions has been developed in MATLAB to retrieve refractive indices from aerosol particle extinction spectra with the classical damped harmonic oscillator model. The aerosols are assumed to be spherical so that Mie theory can be applied to calculate the extinction efficiency and its derivatives. The particle size distribution is lognormal but can be easily adapted to other forms of distributions. The retrieved parameters are the particle distributions mean radius rm, the standard deviation σ, the dielectric constants at high frequenc
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
FTIR STUDIES OF AMMONIA PHOTOCHEMISTRY IN SOLID PARAHYDROGEN
No full textAuthor Institution: Department of Chemistry, University of Wyoming, Laramie, WY 82071-3838It is believed that producing and trapping high concentrations of reactive species in solid molecular hydrogen will ultimately lead to the development of new high performance rocket fuels.\textbf{189}, 351-365 (1994).} We think the NH radical could be a viable candidate and try to produce it by photolyzing ammonia (NH) at low temperature in solid parahydrogen. Upon 193.3 nm photolysis of NH, we observe both NH and NH radical photoproducts. No significant changes in the NH radical concentration have been detected during a period of 3 hours at 1.8 K, even though the reaction NH + H \rightarrow NH is highly exothermic and can occur by quantum mechanical tunneling even at these low temperatures. In contrast, the NH radical is only observed in FTIR scans recorded during photolysis and rapidly decays once the 193.3 nm laser is turned off. We will discuss the possible fates of NH and how conditions can be optimized to produce high concentrations of NH radicals
DETECTING HYDROGEN ATOMS IN SOLID PARAHYDROGEN USING FTIR SPECTROSCOPY
No full textAuthor Institution: Department of Chemistry, University of Wyoming, Laramie, WY 82071-3838Our group is currently studying the 193.3 nm photochemistry of a number of precursor molecules isolated in solid parahydrogen (pH) using high-resolution FTIR spectroscopy. In photochemical studies of formic acid\textbf{3}, 342-347 (2012).} and ammonia, right after the photolysis laser is turned off, we observe metastable satellite peaks in close proximity to the strong rovibrational transition out of the ground state of the respective monomer photoproducts HO and NH. In both cases, there are two satellite peaks near the R(0) monomer transition. We have assigned these satellite features to H-HO and H-NH radical clusters that form via reactions of the photoproduct with the pH host. We will present IR spectroscopic studies of these two H-atom cluster systems that we hope to use in future photochemical studies to measure the concentration of H-atoms in our sample using FTIR spectroscopy
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
INFRARED SPECTROSCOPY OF HNO AND NOH SUSPENDED IN SOLID PARAHYDROGEN
No full textAuthor Institution: Department of Chemistry, University of Wyoming, Laramie, WY 82071-3838The only report in the literature on the infrared spectroscopy of the parent oxynitrene NOH was performed using Ar matrix isolation spectroscopy at 10 K.\textbf{38}, 108-110 (1999).} In this previous study, the NOH is synthesized by co-deposition of NO/Ar and a H/Ar mixture that is passed through a microwave discharge to create H-atoms. The H-atoms recombine with NO in the Ar matrix to produce mostly HNO, but some NOH is produced as well. In this work we irradiate NO doped parahydrogen solids at 2 K using 193 nm radiation which is known to generate H-atoms as by-products.\textbf{29}, 740-743 (2003).} After the photolysis laser is stopped, we detect growth of HNO and NOH presumably due to reactions of H-atoms with NO analogous to the previous Ar matrix study. The higher energy NOH isomer is predicted by high-level calculations to be in a triplet ground electronic state.\textbf{136}, 164303 (2012).} Interestingly, the infrared absorptions of NOH for the two observed vibrational modes (bend and OH stretch) display fine structure; an intense central peak with smaller peaks spaced symmetrically to both lower and higher wavenumbers. Further, the spacing between the peaks is the same for both vibrational modes. We believe this fine structure reflects the zero-field splitting of the triplet ground state of NOH (magnetic dipole-dipole interaction) and our most current results and analysis will be presented
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
