1,720,956 research outputs found
Statistical thermodynamics for beginners
No full textThis book is the distilled essence of the author teaching statistical mechanics to juniors, seniors and graduate students for over 50 years in various course settings. It uses a unique approach that leads naturally into the development of all possible ensembles. Much of the later chapters on polymers has previously been available only in the literature. Throughout the book, the assumption is made that the reader is still relatively raw, and mathematical detail is provided that other books leave to the abilities of the reader. While this produces a plethora of equations that mature scientists would regard as unnecessary, it is intended to help those just coming into the field and who want to get the idea without suffering hours of agony wondering, 'where did that come from?'
INTENSITY SUM RULE FOR ITERATED VIRGULATE STRUCTURES
No full textR.F. Schaufele and T. Shimanouchi, J. Chem. Phys. 47, 3605(1967).Author Institution: Department of Chemistry, University of MassachusettsSchaufele and frist showed that low frequency Raman active vibrations of long chain hydrocarbons could be explained as longitudinal acoustic modes associated with odd numbers of nodes, or zeroes of the motion, along the hydrocarbon chain. The experimental which a polarization dependence of the from \begin{equation} \alpha=\alpha_{0}+\alpha_{1}\sum\nolimits_{i}\Delta\ell_{i}+\cdots \end{equation} was assumed. To the extent that this bond polarizability model can be applied to real molecules, there is a precise intensity sum rule which is embedded in the mathematics of the transformation from the basis coordinates to the normal coordinates appropriate to such iterated virgulate structures. If is the reduced mass for motio-n , the sum rule has the from \begin{equation} \frac{1}{2\mu\alpha_{1}^{2}}\sum\limits^{n-1 \hbox{ or } n-2}_{m_{ odd}{=1}}(\partial\alpha/\partial Q_{m})^{2} =1 \end{equation} In this paper, this intensity sum rule will be derived, and the scope of applicability will be discussed. Some real physical examples will be presented
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
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
AQUEOUS PYRIDINE BOROHYDRIDE-SILVER SOLS. II. MULTIPLE SITE ABSORPTION
No full textAuthor Institution: Department of Chemistry, University of Massachusetts AmherstRaman spectra of pyridine-2,6-, pyridine-3,5-, pyridine-4-d and pyridine in aqueous sodium borohydride generated silver sols display time evolving multiplicity of surface enhanced Raman scattering (SERS) active bands. Addition of gelatine, polyvinyl alcohol or agar agar alters the intensity characteristics of some components of each SERS active vibration, allowing identification of bands in pyridine adsorbed onto different crystal faces of the metallic silver substrate. The isotopic data allow investigation of alterations of the molecular force field induced by adsorption onto different sites
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
AQUEOUS PYRIDINE BOROHYDRIDE-SILVER SOLS. I. DEPOLARIZATION RATIOS AND POLARIZATION DISPERSION
No full textAuthor Institution: Department of Chemistry, University of Massachusetts AmherstDepolarization ratios of surface enhanced Raman scattering (SERS) active fundamentals of pyridine in acqueous sodium borohydride generated silver sols are reported for a number of different pyridine concentrations. Observed depolarization ratios fluctuate substantially in intervals of time short compared with the time required to complete depolarization ratio measurements. These ratios are between 1 and 1/3, are essentially the same for all SERS active pyridine vibrations in a particular preparation, and evolve in time toward a limiting value of 1/3. Dispersion of polarization which evolves in time is found in the so-called molecule-metal stretching vibration found near . A simple physical model of the scattering process is suggested which accords closely enough with these facts to be useful while retaining sufficient simplicity to allow qualitative insight into the behaviour of these complex colloidal systems
- …
