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81.
Alfred Seeger 《Philosophical Magazine Letters》2013,93(10):699-706
Recently, low-frequency internal friction measurements on a series of Fe–Cr alloys by Konstantinovi? and Terentyev [M.J. Konstantinovi? and D. Terentyev, Mater. Sci. Eng. A 521–522 (2009) p.106] have demonstrated that increasing Cr concentrations lead to an increase in the strength of the β-relaxation at the cost of the γ-relaxation (Chambers’ notation). In the same concentration and temperature regime, the alloys show alloy softening. It is argued that both phenomena are due to the same process, namely the influence of foreign atoms on the transformation of the cores of a 0?1 1 1?/2 screw dislocations from their low-temperature configuration, capable of forming kink pairs on {1 1 0} planes, to their high-temperature configuration with kink-pair generation on {2 1 1} planes. 相似文献
82.
Surbhi Narang Saruchi Rani Praveen Aghamkar Sushil Kumar 《Philosophical Magazine Letters》2013,93(8):503-513
Neodymium-doped silica nanocomposites were prepared from an acid-catalysed sol–gel solution followed by heat treatment. The structural and microstructural properties of the prepared samples as a function of sintering temperature and Nd concentration are reported. Fourier transform infrared spectra show that phase separation occurs during heat treatment. The presence of Nd2O3 and α-Nd2Si2O7 phases in the samples was established by X-ray diffraction (XRD), and transmission electron microscopy (TEM) micrographs revealed the microstructure of the nanocomposites. From XRD patterns, the crystallite size was determined using the Debye–Scherrer formula, while the particle size was estimated from TEM micrographs. The results suggest that sintering at high temperature enhances the crystallinity and density of Nd2O3–SiO2 nanocomposites, while the high concentration of neodymium prevents the crystallization of SiO2. 相似文献
83.
Zn1???xCoxO (ZC) [x?=?0, 1, 3, 5, 7 and 9?mol%] thin films were prepared by sol–gel combined metallo-organic decomposition method. The films were deposited on the Si substrate with spin-coating technique and annealed at 600?°C for 3?h. X-ray diffraction pattern shows the formation hexagonal wurtzite phase and distortion (c/a) decreases with increasing Co concentration in ZnO. The average grain size is measured using Scherer relation. Atomic force microscopy is used to confirm the formation of nanograins resulted by the use of polyethylene glycol as surfactant. The photoluminescence was recorded by using He-Cd laser of excitation wavelength 325?nm in wavelength region of 350–650?nm which exhibits some influence of Co doping on the multiplication of defects such as O vacancies, Zn interstitials and grain boundary defects. All thin films show room temperature ferromagnetism except pure ZnO which is diamagnetic and 9?mol% of Co shows paramagnetism. This behaviour is interpreted as due to fluctuations in the magnetic ordering, depending on grain size and site location in grain boundaries or oxygen vacancies. 相似文献
84.
In this letter, the dislocation patterns on the common primary slip plane in a fatigued \[1-34]-\[182-7] copper bicrystal with a Sigma=19b grain boundary (GB) have been investigated using the electron channelling contrast technique in a scanning electron microscope. The results show that the two-phase dislocation structure, such as veins and persistent slip band (PSB) walls, embedded within veins, can be clearly seen on the common primary slip plane. In particular, the interactions of PSBs with the GB are clearly revealed. It is found that there are three kinds of interaction mode between the GB and the dislocations during cyclic deformation, and those are discussed. It is suggested that the dislocations carried by PSBs cannot transfer through the GB continuously even though the bicrystal has a common primary slip plane and its surface slip bands are continuous across the GB. 相似文献
85.
Using molecular dynamics, we study the role of the surface facets of III–V nanowires on their failure during tensile deformation. We find that wurtzite (WZ) nanowires can withstand higher levels of stress and strain at failure compared to zinc-blende (ZB) nanowires. We observe that it is easier to nucleate a crack on a ZB nanowire due to the stress singularities that occur at the intersection of two opposing {111} facets. In WZ nanowires, we observe that cracks always nucleate at the intersection between two adjacent {112} surface facets. We explain these phenomena using fracture mechanics techniques based on energetics of crack formation. 相似文献
86.
87.
Mikko Ketola 《International Journal for the Study of the Christian Church》2013,13(3):225-239
This article analyses and describes the recent history of the Baltic churches, their theological reorientation and the challenges they have encountered in the post-Communist Baltic society. The focus is on the Estonian, Latvian and Lithuanian Lutheran churches whereas the Catholic and Orthodox churches receive less attention. It is first demonstrated that much has changed since the Second World War regarding the churches' membership numbers and their societal position. The article then pays attention to two phenomena that have caused much discussion not only within the churches but also among foreign observers: the fear that the Lutheran Church will surrender to the Catholic Church, and the quite opposite anxiety that the Lutheran Church–Missouri Synod will grow too influential within Baltic Lutheranism. Finally, the author examines the way the Baltic churches have been involved in politics during the last two decades. 相似文献
88.
Thomas Girmalm Marie Rosenius 《International Journal for the Study of the Christian Church》2013,13(1):48-58
The aim of this article is to discuss the current legislation, and power structures in and between different levels of the Church of Sweden in terms of church–state relations and secularisation, with the help of theories from sociology of religion and ecclesiology drawn from José Casanova, Grace Davie and Avery Dulles. With themes from Lutheran theology, including the two regiments and the common priesthood of all believers, we analyse the current legislation and power structures from the perspective of the so-called ‘dual line of responsibility’. The underlying hypothesis is that the structures of the former state church are still deciding the power structures in the Church of Sweden. This creates obscurity concerning the role of the church in public society and negatively affects the ecclesiastical development of the church now that it has lost its earlier status as a state church. 相似文献
89.
Forty consecutive participants in a comprehensive, behaviourally oriented coronary rehabilitation and secondary prevention program were followed for three years. Changes in depression (as measured with the Beck Depression Inventory) as well as the influence of baseline levels of depression on achieved changes in lifestyle behaviour and on rehabilitation and secondary prevention effects were analyzed. Subjects with moderate levels of baseline depression experienced short-term reductions of depression, which was maintained at the 12-month follow-up. Clinically depressed subjects experienced less positive results, with smaller immediate reductions as well as relapse to baseline levels after 12 months, specifically in non-physical, cognitive-affective depression symptoms. There were, however, no differences in lifestyle changes or in hospital treatment between groups with different pre-treatment depression levels. These results are discussed in relation to earlier research on the detrimental effects of depression on the prognosis of coronary artery disease. 相似文献
90.
Abstract The current pilot study aimed at providing an initial assessment of how anxiety influences police officers’ shooting behavior. Seven police officers participated and completed an identical shooting exercise under two experimental conditions: low anxiety, against a non-threatening opponent, and high anxiety (HA), against a threatening opponent who occasionally shot back using colored soap cartridges. Measurements included shooting accuracy, movement times, head/body orientation, and blink behavior. Results showed that under HA, shooting accuracy decreased. Underlying this degradation of performance, participants acted faster and made themselves smaller to reduce the chance of being hit. Furthermore, they blinked more often, leading to increases in the amount of time participants had their eyes closed. Findings provide support for attentional control theory, hereby also pointing to possible interventions to improve police officers’ shooting performance under pressure. 相似文献