1,720,976 research outputs found
LASER-DRIVEN CHANNELS OF REACTIVE COLLISIONS IN NA PLUS CD VAPORS
No full textWe report the observation of reactive collisions involving laser excited metastable 5p 3P1 Cd atoms and ground state Na2 molecules. As result of these collisions the NaCd intermetallic excimer is formed in a bound excited electronic state and its typical bound-free emission to the ground state is detected. Experimental comparison of this new collision channel with the photochemical production of NaCd in collisions between electronically excited Na2 and ground state Cd atoms is presented
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
NONLINEAR EMISSION IN SODIUM VAPOR UPON PULSED-LASER EXCITATION OF THE 4(2)P LEVELS
No full textParametric four-wave mixing, stimulated electronic Raman scattering and amplified spontaneous emission cascades have been studied experimentally by single-photon resonant and near-resonant excitation of the 4 P-2 levels of dense sodium vapour. The dependence of emission intensities on laser detuning and exciting laser power is discussed
PRODUCTION OF THE ELECTRONICALLY EXCITED NACD EXCIMER VIA RESONANT EXCITATION OF THE METASTABLE CD(5P(3)P(1)) LEVEL
No full textWe report the first evidence for the production of the electronically excited NaCd excimer following resonant excitation of the metastable Cd(5p P-3(1)) state. Dependence of intensity of emission from NaCd upon buffer gas pressure, temperature, and exciting laser wavelength is discussed and possible production mechanisms are proposed
Observation of collisional energy transfer from laser excited Cd atoms to Na(4p P-2(J)) atoms
No full textTransfer of excitation from cadmium to sodium atoms was investigated in an heat pipe oven illuminated by a pulsed laser tuned on the intercombination transition of cadmium. A rich emission spectrum with cadmium as well as sodium lines was observed. Intramultiplet mixing distributes the initial excited level population 5p(3)P(1) to the nearby fine structure levels 5p(3)P(0,2) of the same multiplet. We have experimental evidence that the energy transfer pathway is from Cd (5p(3)P(J)) to Na(4p(2)P(J)) which is collisionally rapidly converted to Na(3d(2)D(J)), from which the strongest emission was observed
STUDY OF THE LIHG EXCIMER - BLUE-GREEN BANDS
No full textWe report for the first time the production of the LiHg excimer by a photochemical reaction of excited Li-2 molecules with Hg(6s(2 1)S(0)) Excitation energy was provided by a cw ultraviolet (UV)-argon ion laser operating in single-line and in multi-line mode or by pulsed XeCl excimer laser at 3080 Angstrom. We observed bound-free emission of LiHg in the form of diffuse bands peaking at 4450 and at 4670 Angstrom. The latter was structured by bound-bound emission lines. Relativistic ab initio calculations for the potential energy curves of LiHg and for the relevant dipole transition moments were performed. Using these results, an interpretation of the observed emission is presented
Variations on the Author
Full text link“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
Full text linkWe 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
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