Direct Evidence of Diffusion of Self-Interstitials in Silicon

1982 ◽  
Vol 14 ◽  
Author(s):  
Gobinda Das
Keyword(s):  
High Temperature ◽  
Large Scale ◽  
Direct Evidence ◽  
Theoretical Calculations ◽  
Dominant Role ◽  
Diffusion Mechanism ◽  
Float Zone ◽  
Diffusion Characteristics ◽  
Silicon Interface

ABSTRACTHigh temperature (1200°C) HCI oxidation treatment has been employed to float-zone (FZ) silicon wafers (625μm thick) containing swirl defects in order to study their diffusion characteristics. In treated wafers, swirl defects can be eliminated from both surfaces up to a depth of ∼30μm. In the bulk of the wafers, however, large swirl defects (A-swirls) rearrange themselves into many small defects. The untreated portions of wafers contain large swirl defects (A-swirls) that extend up to both surfaces. Since swirl defects are primarily clusters of silicon self-interstitials, their rearrangement in the bulk and elimination from the surfaces demonstrate that migration of interstitials takes place on a large scale and is not confined to SiO2/ silicon interface only. The above observations appear to provide direct evidence for the dominant role of self interstitials for diffusion mechanism in silicon at high temperature and can be rationalized in terms of an interstitialcy mechanism. Alternatively, however, dominance of interstitials can be related to a higher migration energy of vacancies proposed in a model where both species coexist at high temperature. The preference of one model over another must await theoretical calculations of diffusion energetics derived from both models.

scholarly journals Combined Forces: Thinking and/or Feeling? How News Consumption Affects Anti-Muslim Attitudes through Perceptions and Emotions about the Economy

2018 ◽  
Vol 67 (2) ◽  
pp. 326-347 ◽  
Author(s):  
Laura Jacobs ◽  
Mark Boukes ◽  
Rens Vliegenthart
Keyword(s):  
Structural Equation ◽  
Large Scale ◽  
Dominant Role ◽  
Empirical Support ◽  
Equation Model ◽  
Conflict Theory ◽  
News Consumption ◽  
Group Conflict Theory ◽  
News Outlet

This study develops a model that contributes to our understanding of the complex relationship between economic motivations and anti-Muslim attitudes by analyzing the underexplored role of news consumption. Using a large-scale Dutch panel dataset ( n = 2694), we test a structural equation model theoretically grounded in group conflict theory, in which the relationship between news consumption and anti-Muslim attitudes is mediated by perceptions and emotions about the economy. Findings offer sound empirical support for the hypothesized model: news consumption increases pessimistic economic perceptions and negative emotions about the economy, which in turn strengthens anti-Muslim attitudes. The mechanism, however, largely depends on the type of news outlet and genre: watching television seems more decisive than reading newspapers; moreover, especially exposure to soft and popular news formats plays a dominant role.

The trajectory of geomorphology

2010 ◽  
Vol 34 (3) ◽  
pp. 265-286 ◽  
Author(s):  
Michael Church
Keyword(s):  
Twentieth Century ◽  
Large Scale ◽  
Earth Science ◽  
Dominant Role ◽  
Historical Interpretation ◽  
Spatial And Temporal Scales ◽  
Absolute Dating ◽  
The Subject ◽  
Living Organisms

Modern geomorphology was founded in the nineteenth century as an exercise of historical interpretation of landscapes. After the mid-twentieth century it dominantly became a quest to understand the processes by which landscapes are modified. This focused attention on the measurement of sediment fluxes on synoptic timescales and on a reductionist, Newtonian programme of construction of low-order theories about those fluxes, largely imported from engineering science. The period also saw the emergence of an applied geomorphology. Toward the end of the twentieth century the subject was dramatically transformed by improved technologies for remote sensing and surveying of Earth’s surface, the advent of personal computation and of large-scale computation, and important developments of absolute dating techniques. These technical innovations in turn promoted recognition of geomorphology as a ‘system science’ and facilitated the reintegration of tectonics into geomorphology, opening the way for a renewed consideration of the history of the landscape. Finally, increasing recognition of the dominance of human agency in contemporary modification of Earth’s terrestrial surface has become a significant theme. Important influences on the continuing development of the subject will include the search for physically sound laws for material fluxes; reconciling geomorphological information and process representations across spatial and temporal scales, in both observation and theory; comprehending complexity in geomorphological processes and landform histories; incorporating the geomorphological role of living organisms, particularly micro-organisms; understanding the role of climate in geomorphology, both in the contemporary changing climate and in the long term; and fully admitting the now dominant role of humans as geomorphic agents. Geomorphology is simultaneously developing in diverse directions: on one hand, it is becoming a more rigorous geophysical science — a significant part of a larger earth science discipline; on another, it is becoming more concerned with human social and economic values, with environmental change, conservation ethics, with the human impact on environment, and with issues of social justice and equity.

scholarly journals ‘Horror Vacui’ in the Oxygen Sublattice of Lithium Niobate Made Affordable by Cationic Flexibility

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 764
Author(s):  
Gábor Corradi ◽  
László Kovács
Keyword(s):  
Large Scale ◽  
Dominant Role ◽  
Internal Surface ◽  
Charge Compensation ◽  
Oxygen Sublattice ◽  
Vacancy Defects ◽  
Close Relationship ◽  
Li Battery ◽  
Mechanochemical Treatments

The present review is intended to interest a broader audience interested in the resolution of the several decades-long controversy on the possible role of oxygen-vacancy defects in LiNbO3. Confronting ideas of a selected series of papers from classical experiments to brand new large-scale calculations, a unified interpretation of the defect generation and annealing mechanisms governing processes during thermo- and mechanochemical treatments and irradiations of various types is presented. The dominant role of as-grown and freshly generated Nb antisite defects as traps for small polarons and bipolarons is demonstrated, while mobile lithium vacancies, also acting as hole traps, are shown to provide flexible charge compensation needed for stability. The close relationship between LiNbO3 and the Li battery materials LiNb3O8 and Li3NbO4 is pointed out. The oxygen sublattice of the bulk plays a much more passive role, whereas oxygen loss and Li2O segregation take place in external or internal surface layers of a few nanometers.

scholarly journals A Review of Bovine Tuberculosis in the Kafue Basin Ecosystem

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Musso Munyeme ◽  
Hetron Mweemba Munang'andu
Keyword(s):  
Bovine Tuberculosis ◽  
Large Scale ◽  
Wildlife Conservation ◽  
Direct Evidence ◽  
Natural Habitat ◽  
Epidemiological Data ◽  
Livestock Production ◽  
Commercial Fishing ◽  
Kafue Lechwe

The Kafue basin ecosystem is the only remaining natural habitat for the endangered Kafue lechwe antelope (Kobus leche Kafuensis). However, hydroelectricity power production, large-scale sugar plantations, commercial fishing and increasing livestock production are threatening its natural existence and sustainability. Further, increasing human settlements within and around the Kafue basin have resulted in decreased grazing grounds for the Kafue lechwe antelopes despite a corresponding increase in cattle population sharing the same pasture. Baseline epidemiological data have persistently reported findings of bovine tuberculosis (BTB) in both wild and domestic animals, although these have been deficient in terms of describing direct evidence in the role of either lechwe antelopes or cattle in the reported observations. Despite the current literature being deficient in establishing the casual role and transmission patterns of BTB, a bimodal route of infection at the livestock/wildlife interface has been postulated. Likewise, it is not known how much of (BTB) has the potential of causing disease in humans. This paper, seeks to underline those aspects that need further research and update available data on BTB in the Kafue basin with regards to the prevalence, distribution, risk factors, threats on wildlife conservation, livestock production, public health implications, and possible mitigatory measures.

scholarly journals Pedagogical Approaches to Mastering Polyphonic Cycles by J. S. Bach and D. D. Shostakovich in the Piano Class by Students of the People’s Republic of China

2019 ◽  
Vol 7 (3) ◽  
pp. 105-125
Author(s):  
Elena P. Krasovskaya ◽  
Ho Da
Keyword(s):  
Music Education ◽  
Large Scale ◽  
Dominant Role ◽  
Republic Of China ◽  
Piano Students ◽  
Preludes And Fugues ◽  
Characteristic Features ◽  
Professional Interpreting ◽  
Pedagogical Approaches

In the article the problems of mastering the binary cycles by J. S. Bach and D. D. Shostakovich included in large-scale polyphonic collections of the composers (“Well-Tempered Clavier” and “Twenty-Four Preludes and Fugues”, opus 87) by the Chinese piano students are considered. It is shown that these problems are caused by the features of the Chinese system of music education based on the characteristic features of national culture (monodiality, the dominant role of the pentatonic-modal system, the intonation dictionary and the logic of the deployment of content, fundamentally different from the European interpretation) and also by a low level of theoretical knowledge of students about polyphonic music and the traditions of its interpretation. According to the authors, an important step to understanding and professional interpreting the polyphonic heritage of the composers by Chinese students may be the intonation, civilized and paradigm-pedagogical approaches. The consistent transition from national patterns of polyphony to European polyphonic works, their study through the prism of the proposed pedagogical approaches allowed students to understand the phenomenon of polyphony in the musical art, to trace traditions and innovations in it. This has a positive effect on mastering polyphonic opuses by students.

scholarly journals Mass of Abrikosov vortex in high-temperature superconductor YBa$$_2$$Cu$$_3$$O$$_{7-\delta }$$

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Roman Tesař ◽  
Michal Šindler ◽  
Christelle Kadlec ◽  
Pavel Lipavský ◽  
Ladislav Skrbek ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
High Temperature ◽  
High Temperature Superconductor ◽  
Dominant Role ◽  
High Temperature Superconductors ◽  
Abrikosov Vortex ◽  
Circular Dichroïsm ◽  
The Magnetic Field ◽  
Zero Frequency

AbstractFor more than four decades, mass of Abrikosov vortices defied experimental observations. We demonstrate a method of its detection in high-temperature superconductors. Similarly to electrons, fluxons circulate in the direction given by the magnetic field, causing circular dichroism. We report the magneto-transmittance of a nearly optimally doped thin YBa$$_2$$ 2 Cu$$_3$$ 3 O$$_{7-\delta }$$ 7 - δ film, measured using circularly polarized submillimeter waves. The circular dichroism emerges in the superconducting state and increases with dropping temperature. Our results confirm the dominant role of quasiparticle states in the vortex core and yield the diagonal fluxon mass of $$2.2 \times 10^8$$ 2.2 × 10 8 electron masses per centimeter at 45 K and zero-frequency limit, and even larger off-diagonal mass of $$4.9 \times 10^8 m_e$$ 4.9 × 10 8 m e /cm.

scholarly journals The role of dew and radiation fog inputs in the local water cycling of a temperate grassland in Central Europe

2020 ◽  
Author(s):  
Yafei Li ◽  
Franziska Aemisegger ◽  
Andreas Riedl ◽  
Nina Buchmann ◽  
Werner Eugster
Keyword(s):  
Water Vapor ◽  
Large Scale ◽  
Water Cycle ◽  
Dominant Role ◽  
Temperate Grassland ◽  
Ambient Water ◽  
Radiation Fog ◽  
Dew Formation ◽  
Local Water

Abstract. In a warmer climate, non-rainfall water (hereafter NRW) formed from dew and fog potentially plays an increasingly important role in temperate grassland ecosystems under the scarcity of precipitation over prolonged periods. Dew and radiation fog occur in combination during clear and calm nights, and both use ambient water vapor as a source. Research on the combined mechanisms involved in NRW inputs to ecosystems are rare, and the condensation of soil-diffusing vapor, as one of the NRW input pathways for dew formation, has hardly been studied at all. The aim of this paper is thus to investigate the different NRW input pathways into a temperate Swiss grassland at Chamau during prolonged dry periods in summer 2018. We measured the isotopic compositions (δ18O, δ2H, and d = δ2H − 8 · δ18O) of both ambient water vapor and the NRW droplets on leaf surfaces combined with eddy covariance and meteorological measurements during one dew-only and two combined dew and radiation fog events. We employed a simple two end-member mixing model using δ18O and δ2H to split the dew input pathways from different sources. Our results showed a decrease of 0.8–5.5 mmol mol−1 in volumetric water vapor mixing ratio and a decrease of 4.8–16.7 ‰ in ambient water vapor δ2H due to dew formation and radiation fog droplet deposition. A nighttime maximum in ambient water vapor δ18O (−15.5 ‰ to −14.3 ‰) and a 3.4–3.7 ‰ decrease in ambient water vapor d were observed for dew formation in unsaturated conditions. In conditions of slight super-saturation, a stronger decrease of ambient water vapor δ18O (0.3–1.5 ‰) and a minimum of ambient water vapor d (−6.0 ‰ to −4.7 ‰) were observed. The combined foliage NRW and ambient water vapor δ18O and δ2H suggested two different input pathways: (1) condensation of ambient water vapor and (2) of soil-diffusing vapor. The latter contributed 9–42 % to the total foliage NRW. The dew and radiation fog potentially produced 0.06–0.39 mm night−1 NRW gain on foliage, which was comparable with 2.8 mm day−1 daytime evapotranspiration. The ambient water vapor d was correlated and anti-correlated with ambient temperature and ambient relative humidity respectively, suggesting an only minor influence of large-scale air advection and highlighted the dominant role of local moisture as a source for ambient water vapor. Our results thus highlight the importance of NRW inputs to temperate grasslands during prolonged dry periods and reveal the complexity of the local water cycle in such conditions including different pathways of water deposition.

scholarly journals Bi-directional streaming of particles accelerated at the STEREO-A shock on 2008 March 9

2020 ◽  
Vol 499 (2) ◽  
pp. 2087-2093
Author(s):  
F Fraschetti ◽  
J Giacalone
Keyword(s):  
Magnetic Field ◽  
Large Scale ◽  
Dominant Role ◽  
Reverse Shock ◽  
Measured Intensity ◽  
Particle Simulations ◽  
Field Lines ◽  
Run Test ◽  
The Magnetic Field

ABSTRACT We present an interpretation of anisotropy and intensity of supra-thermal ions near a fast quasi-perpendicular reverse shock measured by Solar Terrestrial Relations Observatory Ahead (ST-A) on 2008 March 9. The measured intensity profiles of the supra-thermal particles exhibit an enhancement, or ‘spike’, at the time of the shock arrival and pitch-angle anisotropies before the shock arrival are bi-modal, jointly suggesting trapping of near-scatter-free ions along magnetic field lines that intersect the shock at two locations. We run test-particle simulations with pre-existing upstream magnetostatic fluctuations advected across the shock. The measured bi-modal upstream anisotropy, the nearly field-aligned anisotropies up to ∼15 min upstream of the shock, as well as the ‘pancake-like’ anisotropies up to ∼10 min downstream of the shock are well reproduced by the simulations. These results, in agreement with earlier works, suggest a dominant role of the large-scale structure (100s of supra-thermal proton gyroradii) of the magnetic field in forging the early-on particle acceleration at shocks.

scholarly journals The Role of Environment on High Temperature Creep-Fatigue Behavior of Alloy 617

2010 ◽  
Author(s):  
Laura Carroll ◽  
Celine Cabet ◽  
Richard Wright
Keyword(s):  
High Temperature ◽  
Grain Boundary ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Dominant Role ◽  
Hold Time ◽  
Outlet Temperature ◽  
Alloy 617 ◽  
Creep Fatigue

Alloy 617 is the leading candidate material for an intermediate heat exchanger (IHX) application of the Very High Temperature Nuclear Reactor (VHTR), expected to have an outlet temperature as high as 950°C. Acceptance of Alloy 617 in Section III of the ASME Code for nuclear construction requires a detailed understanding of the creep-fatigue behavior. Initial creep-fatigue work on Alloy 617 suggests a more dominant role of environment with increasing temperature and/or hold times evidenced through changes in creep-fatigue crack growth mechanism/s and failure life. Furthermore, previous work on corrosion of nickel base alloys in impure helium has suggested that this environment is far from inert with respect to Alloy 617. Continuous cycle fatigue and creep-fatigue testing of Alloy 617 was conducted at 950°C and 0.3% and 0.6% total strain in air to simulate damage modes expected in a VHTR application. Continuous cycle and creep-fatigue specimens exhibited intergranular cracking, but did not show evidence of grain boundary cavitation. Despite the absence of grain boundary cavitation to accelerate crack propagation, the addition of a hold time at peak tensile strain was detrimental to cycle life. This suggests that creep-fatigue interaction may occur by a different mechanism or that the environment may be partially responsible for accelerating failure.

Chronic Pain: Fundamental Scientific Considerations, Specifically for Legal Claims

2013 ◽  
Vol 18 (1) ◽  
pp. 1-18 ◽  
Author(s):  
Robert J. Barth
Keyword(s):  
Health Outcomes ◽  
Pain Perception ◽  
Driving Forces ◽  
Psychological Treatment ◽  
Dominant Role ◽  
Meta Analysis ◽  
General Medicine ◽  
Pain Syndrome ◽  
Problematic Relationship

Abstract Scientific findings have indicated that psychological and social factors are the driving forces behind most chronic benign pain presentations, especially in a claim context, and are relevant to at least three of the AMA Guides publications: AMA Guides to Evaluation of Disease and Injury Causation, AMA Guides to Work Ability and Return to Work, and AMA Guides to the Evaluation of Permanent Impairment. The author reviews and summarizes studies that have identified the dominant role of financial, psychological, and other non–general medicine factors in patients who report low back pain. For example, one meta-analysis found that compensation results in an increase in pain perception and a reduction in the ability to benefit from medical and psychological treatment. Other studies have found a correlation between the level of compensation and health outcomes (greater compensation is associated with worse outcomes), and legal systems that discourage compensation for pain produce better health outcomes. One study found that, among persons with carpal tunnel syndrome, claimants had worse outcomes than nonclaimants despite receiving more treatment; another examined the problematic relationship between complex regional pain syndrome (CRPS) and compensation and found that cases of CRPS are dominated by legal claims, a disparity that highlights the dominant role of compensation. Workers’ compensation claimants are almost never evaluated for personality disorders or mental illness. The article concludes with recommendations that evaluators can consider in individual cases.

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