1,722,156 research outputs found
Spectrometric study of condensed phase species of thorium and palladium-based modifiers in a complex matrix for electrothermal atomic absorption spectrometry
No full textThe chemical and morphological transformations of condensed phase species of a thorium-based modifier were studied over the temperature range 200–2500 °C, without and with the presence of aluminium and silicon as matrix components, and in some instances, arsenic as an analyte element. A similar study was also conducted with palladium as the modifier, for comparison. Results were derived using scanning electron microscopy (SEM), energy dispersive (ED) X-ray spectrometry, Raman microanalysis and attenuated total reflectance (ATR) Fourier transform-infrared (FT-IR) spectrometry. Comparable results were found using pyrolytic and non-pyrolytic graphite platforms, with processes occurring at slightly higher temperatures on the pyrolytic graphite platform. With thorium as the modifier, metal oxides were the predominant species on the platform surface at relatively low temperatures (<1500 °C), whereas metal phases became prevalent at high temperatures, when thorium and aluminium tended to behave independently from one other. Some spatial variations in the composition of the salt residues on different regions of the platform were observed (from the region closest to the slot in the tube, to the region furthest from the slot). Nonetheless, thorium metal remained on the graphite platform to higher temperatures than did aluminium metal. In the presence of arsenic, the existence of mixtures of thorium and arsenic oxides, just before the appearance temperature of gas phase arsenic atoms, was confirmed by SEM studies, ED X-ray spectra and Raman microanalysis. This suggests that any modifying effect of thorium on arsenic occurs while the modifier is in the oxide phase rather than in the metal phase. The presence of silicon added as silica, did not influence significantly the thermochemical behaviour of mixtures of thorium and aluminium. However, coexistence of silicon and arsenic oxides at the appearance temperature of the atomic absorption signal of arsenic was obtained, confirming that silicon can act as an internal modifier for arsenic. In the presence of palladium, aluminium exhibited greater interaction with the modifier; consequently, aluminium metal was retained on the platform surface to higher temperatures than thorium, which could explain how interference effects of aluminium on e.g. arsenic are avoided or reduced. Similarly, there was evidence for interaction of palladium and arsenic in the reduced state. However, when aluminium and silicon were present, the transformation of the palladium oxide to the metallic state was affected, which could diminish the modifying benefits of palladium for arsenic in the presence of aluminium
A systemic approach to translating style: a comparative study of four Chinese translations of Hemingway’s The Old Man and the Sea
No full textThe visibility of translators in translated texts has been increasingly recognised, yet research on the translator’s voice and the methodological issues concerned has remained sparse. Corpus-based methods allow only limited access to the motivation of the translator’s choices, and need to be complemented by other research tools to form a coherent methodology for investigating a translator’s style.
The thesis adopts an interdisciplinary approach, combining systemic linguistics and corpus studies with sociohistorical research within a descriptive framework to study the translator’s discursive presence in the text. This approach is as yet underexplored in translation studies.
My work examines four Chinese translations of Hemingway’s The Old Man and the Sea (1952), by Hai Guan (1956), Wu Lao (1987), Li Xiyin (1987) and Zhao Shaowei (1987). The investigation concerns the rendering of transitivity, modality, direct speech and free direct thought presentation as well as the transitions of modes of point of view. It also inquires into the causes of the variation in style between the four translators. I map textual features onto specific sociocultural and ideological contexts of production in an attempt to identify correlations between them. Another objective is to test the applicability of Halliday’s transitivity model (1994) and Simpson’s model of point of view (1993) to the analysis of Chinese translated texts, and to explore possible adjustments to these models to make them serviceable for translation comparison between English and Chinese. The thesis has six chapters: (1) Theoretical approaches, methodological tools and framework, (2) Location of the texts within the sociocultural contexts, (3) Translation of the transitivity system, (4) Translation of point of view, (5) Critical analysis of individual examples and (6) Motivations for translation shifts
Atomic mechanism of internal friction in a model metallic glass
No full textInternal friction (IF) describes the ability of materials to damp out mechanical oscillations. It is a crucial engineering parameter and also conveys unique microscopic information about structural defects, transport phenomena, and phase transformations in solids. While IF predominately results from lattice defects in crystalline materials, the origin of IF remains unclear in disordered materials, like metallic glasses. In this paper, we study the atomic rearrangements that govern IF in a model metallic glass, via numerical simulations of dynamical mechanical spectroscopy together with structural analysis. We identify cooperative and avalanchelike thermal-driven excitations as an underlying mechanism and demonstrate a linearlike relation between the concentrations of these excitations and the values of IF. Structurally, these excitations can be hindered, and thus suppress IF, by slow atoms that usually associate with full icosahedral symmetry. Our results also provide practical guides in tuning IF in metallic glasses from atomistic perspectives.Deutsche Forschungsgemeinschaft (DFG) [FOR 1394
DNA barcodes and morphology confirm a new species of Rheocricotopus (Psilocricotopus) orientalis group (Diptera: Chironomidae)
No full textLin, Xiao-Long, Yu, Hai-Jun, Wang, Qian, Bu, Wen-Jun, Wang, Xin-Hua (2020): DNA barcodes and morphology confirm a new species of Rheocricotopus (Psilocricotopus) orientalis group (Diptera: Chironomidae). Zootaxa 4768 (2): 282-290, DOI: 10.11646/zootaxa.4768.2.
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
The beta relaxation in metallic glasses: an overview
No full textMetallic glasses, combining metallic bonding and disordered atomic structures, are at the cutting edge of metallic materials research. Recent advances in this field have revealed that many key questions in glassy physics are inherently connected to one important relaxation mode: the so-called secondary (beta) relaxation. Here, in metallic glasses, we review the features of beta relaxations and their relations to other processes and properties. Special emphasis is put on their current roles and future promise in understanding the glass transition phenomenon, mechanical properties and mechanisms of plastic deformation, diffusion, physical aging, as well as the stability and crystallization of metallic glasses
Strain induced fragility transition in metallic glass
No full textRelaxation dynamics are the central topic in glassy physics. Recently, there is an emerging view that mechanical strain plays a similar role as temperature in altering the relaxation dynamics. Here, we report that mechanical strain in a model metallic glass modulates the relaxation dynamics in unexpected ways. We find that a large strain amplitude makes a fragile liquid become stronger, reduces dynamical heterogeneity at the glass transition and broadens the loss spectra asymmetrically, in addition to speeding up the relaxation dynamics. These findings demonstrate the distinctive roles of strain compared with temperature on the relaxation dynamics and indicate that dynamical heterogeneity inherently relates to the fragility of glass-forming materials.Deutsche Forschungsgemeinschaft (DFG) [FOR 1394
Universal Origin of Glassy Relaxation as Recognized by Configuration Pattern-matching
Full text linkRelaxation processes are crucial in understanding the structural
rearrangements of liquids and amorphous materials. However, the overarching
principle that governs these processes across vastly different materials
remains an open question. Substantial analysis has been carried out based on
the motions of individual particles. Here, alternatively, we propose viewing
the global configuration as a single entity. We introduce a global order
parameter, namely the inherent structure minimal displacement (IS Dmin), to
quantify the variability of configurations by a pattern-matching technique.
Through atomic simulations of seven model glass-forming liquids, we unify the
influences of temperature, pressure, and perturbation time on the relaxation
dissipation, via a scaling law between the mechanical damping factor and IS
Dmin. Fundamentally, this scaling reflects the curvature of the local potential
energy landscape. Our findings uncover a universal origin of glassy relaxation
and offer an alternative approach to studying disordered systems.Comment: 22 pages, 6 figure
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