1,722,166 research outputs found
Anharmonic vibrational spectroscopy of germanium-containing clusters, Ge(x)C(4−x) and Ge(x)Si(4−x) (x = 0-4), for interstellar detection
No full textAn extensive, high-level theoretical study on tetra-atomic germanium carbide/silicide clusters is presented. Accurate harmonic and anharmonic vibrational frequencies and rotational constants are calculated at the CCSD(T)-F12a(b)/cc-pVT(Q)Z-F12 levels of theory. With growing capabilities to discern more of the chemical composition of the interstellar medium (ISM), an accurate database of reference material is required. The presence of carbon is ubiquitous in the ISM, and silicon is known to be present in interstellar dust grains, however germanium-containing molecules remain elusive. To begin understanding the presence and role of germanium in the ISM, we present this study of the vibrational and rotational spectroscopic properties of various germanium- containing molecules to aid in their potential identification in the ISM with modern observational tools such as the James Webb Space Telescope. Structures studied herein include rhomboidal (r-), diamond (d-), and trapezoidal (t-) tetra-atomic molecules of the form Ge(x)C(4−x) and Ge(x)Si(4−x) , where x=0-4. The most promising structure for detection is r-Ge(2)C(2) via the ν4 mode with a frequency of 802.7 cm−1 (12.5 μm) and an intensity of 307.2 km mol−1. Other molecules potentially detectable, i.e., through vibrational modes or rotational transitions, include r-Ge(3)C, r-GeSi(3), d-GeC(3), r-GeC(3), and t-Ge(2)C(2)
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
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
Experimental investigation of seismic behaviour of corroded RC bridge piers
No full textA summary of shaking table test campaign of three RC columns with different corrosion levels are reported. Accelerated corrosion procedure is employed to produce the desired corrosion level. This work aims to investigate the effects of chloride-induced corrosion on seismic behaviour of RC bridge piers located in a marine environment. The performance of two RC columns in this benchmark test, along with the test result of an uncorroded RC column obtained in authors’ previous work are compared. These three specimens are designed with same dimensions and reinforcement detail. All three columns are subjected to the same input ground motion. The test results of this benchmark shaking table experimental testing are analysed in terms of reinforcement corrosion rate, hysteresis characteristics, response frequency variation and time-effective stiffness monitoring.</p
A 0.5e<sub>rms</sub><sup>−</sup> Temporal Noise CMOS Image Sensor With Gm-Cell-Based Pixel and Period-Controlled Variable Conversion Gain
No full textA deep subelectron temporal noise CMOS image sensor (CIS) with a Gm-cell based pixel and a correlated-double charge-domain sampling technique has been developed for photon-starved imaging applications. With the proposed technique, the CIS, which is implemented in a standard 0.18-μm CIS process, features pixel-level amplification and achieves an input-referred noise of 0.5 e−rms with a correlated double sampling period of 5μs and a row read-out time of 10 μs. The proposed structurealso realizes a variable conversion gain (CG) with a period-controlled method. This enables the read-out path CG and the noise-equivalent number of electrons to be programmable according to the application without any change in hardware. The experiments show that the measured CG can be tuned from 50 μV/e- to 1.6 mV/e- with a charging period from 100 ns to 4μs. The measured characteristics of the prototype CIS are in a good agreement with expectations, demonstrating the effectiveness of the proposed techniques.Accepted Author ManuscriptElectronic Instrumentatio
Si and si(1-x)ge(x) nanokristalleri :
No full textIn this work we have prepared Si and SI(1-X)GE(X) nanocrystals by rf magnetron cosputtering method. The e ect of annealing parameters and Ge content of x on the structural and optical properties sandwiched SiO2/SiO2: Si: Ge/SiO2 nanostructures have been investigated. For characterization we have used cross-sectional high resolution electron microscope (HREM), X-ray di raction (XRD), Raman spectroscopy (RS), Fourier transform infrared (FTIR), photoluminescence (PL), and temperature dependent PL (TDPL) techniques. It was shown that Ge content of x, annealing temperature, and annealing time are important parameters a ecting the structural and optical properties of the nanocrystals. We have observed a uniform SI(1-X)GE(X) nanocrystal formation upon annealing at relatively low temperatures and short annealing time. However, Ge-rich SI(1-X)GE(X) nanocrystals do not hold their compositional uniformity when annealed at high temperatures for enough long time. A segregation process leads to the separation of Ge and Si atoms from each other and formation of Si-rich core covered by a Ge-rich shell. Related to the optical properties of Si and SI(1-X)GE(X) nanocrystals, influence of annealing treatments and Ge content of x on the simultaneous observation and relative contribution of quantum confined and interface related radiative emission to PL spectra are investigated. On the other hand, temperature dependent photoluminescence (TDPL) measurements have been applied to investigate in detail the involving PL mechanisms and the competing thermally activated emission process and the thermally activated escape process of carriers into nonradiative recombination centers and/or tunneling of the excitons into the interface or to larger nanocrystals.Ph.D. - Doctoral Progra
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
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