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81.
This study, conducted with a representative sample of employed and unemployed adults living in Switzerland (N = 2002), focuses on work conditions (in terms of professional insecurity and job demands), career adaptability, and professional and general well-being. Analyses of covariance highlighted that both unemployed and employed participants with low job insecurity reported higher scores on career adaptability and several dimensions (notably on control) than employed participants with high job insecurity. Moreover, structural equation modeling for employed participants showed that, independent of work conditions, adaptability resources were positively associated both with general and professional well-being. As expected professional outcomes were strongly related to job strain and professional insecurity, emphasizing the central role of the work environment. Finally, career adaptability partially mediated the relationship between job strain and professional insecurity, and the outcome well-being.  相似文献   
82.
通勤压力作为一种新型压力源,近年来逐渐成为组织管理领域的前沿话题。通勤压力是指个体在通勤过程中所遭遇的压力事件以及所产生的紧张反应,它对员工的工作态度、工作状态以及工作行为均会产生一定的负面影响,影响强度取决于员工的个人特征、家庭压力以及所处的工作情境。资源保存理论和控制理论是解释通勤压力消极影响的主要理论。未来研究可进一步完善测量工具,考察不同通勤模式的差异化影响效应,丰富边界机制等。  相似文献   
83.
Adolescents of today grow up in a connected world. While online communication offers great opportunities, it can also have negative impact on adolescents' life. In this work, we are interested in the use of online communication tools to share and create cyberhate content. Anchored in the general strain theory, we studied how social support (i.e., parental, peers and teacher support) may be related to cyberhate perpetration. We further tested how personal characteristics such as empathy, self-esteem and anxiety could predict the propensity to be involved as cyberhate perpetrators. We collected self-reported questionnaires of 1019 French young people (13.04 years; ranging from 9 to 17) and measured their perceived (a) parental, (b) peers and (c) teachers' support as well as their (d) empathy/benevolence, (e) self-esteem and (f) anxiety. We also measured cyberhate perpetration and the association between perpetration, social support and personal characteristics. Our results highlight that parental and teacher support represent protective factors for cyberhate perpetration. Our results further suggest that self-esteem is negatively linked to the propensity to cyberhate perpetration.  相似文献   
84.
The internal length is the governing parameter in strain gradient theories which among other things have been used successfully to interpret size effects at the microscale. Physically, the internal length is supposed to be related with the microstructure of the material and evolves during the deformation. Based on Taylor hardening law, we propose a power-law relationship to describe the evolution of the variable internal length with strain. Then, the classical Fleck–Hutchinson strain gradient theory is extended with a strain-dependent internal length, and the generalized Fleck–Hutchinson theory is confirmed here, by comparing our model predictions to recent experimental data on tension and torsion of thin wires with varying diameter and grain size. Our work suggests that the internal length is a configuration-dependent parameter, closely related to dislocation characteristics and grain size, as well as sample geometry when this affects either the underlying microstructure or the ductility of the material.  相似文献   
85.
In this work, we investigate the susceptibility of NiTi superelastic wires to the strain rates during tensile testing after hydrogen charging. Cathodic hydrogen charging is performed at a current density of 10?A/m² during 2–12?h in 0.9% NaCl solution and aged for 24?h at room temperature. Specimens underwent one cycle of loading-unloading reaching a stress value of 700 MPa. During loading, strain rates from 10?6 to 5?×?10?2??s?1 have been achieved. After 8?h of hydrogen charging, an embrittlement has been detected in the tensile strain rate range of 10?6 to 10?4?s?1. In contrast, no embrittlement has been detected for strain rates of 10?3?s?1 and higher. However, after 12?h of hydrogen charging and 24?h of annealing at room temperature, the embrittlement occurs in the beginning of the austenite-martensite transformation for all the studied strain rate values. These results show that for a range of critical amounts of diffused hydrogen, the embrittlement of the NiTi superelastic alloy strongly depends on the strain rate during the tensile test. Moreover, it has been shown that this embrittlement occurs for low values of strain rates rather than the higher ones. This behaviour is attributed to the interaction between the diffused hydrogen and growth of the martensitic domain.  相似文献   
86.
ABSTRACT

This paper considers the characteristics of severe plastic deformation (SPD) to estimate its efficacy and to compare different processing techniques. In contrast to effective strains by von Mises and Hencky, the rotation component of the strain rate is included in the analysis as a mode of deformation, which ranges from simple shear to pure shear. Distortions of material elements during a uniform plane plastic flow are calculated using a kinematic approach. For the fixed deformation mode, the current state is defined by the accumulated shears that are identical to the von Mises effective shear strains. In specific cases of pure shear and simple shear, the accumulated shears match the specific distortions of round or square elements prescribed by Hencky or von Mises approach, respectively. The mode of deformation is important to the structural effects of SPD. In general, two separated characteristics, accumulated shear and the coefficient of deformation mode, are necessary to describe strains during SPD.  相似文献   
87.
88.
Fine-grained copper films on a flexible substrate were cyclically deformed under constant strain range control. It was found that cyclic dislocation plasticity through individual dislocation glide is still dominant at the submicrometer scale, while the ability of irreversible slip of dislocations gradually decreases and the damage was changed from extrusion-induced localization to cracking along grain boundary. Statistical evaluation of the mean spacing between slip bands and/or lines leads to a critical scale (~28 nm) below which dislocation-controlled cyclic strain localization would be shut down.  相似文献   
89.

The behaviour of vacancies during isothermal ageing following quenching of an Al-1.7at.% Mg-1.1at.% Cu alloy has been studied by positron annihilation lifetime spectroscopy. The positron lifetime parameters vary in parallel with the Vickers hardness of the alloy, suggesting simultaneous migration of vacancies and changes in the size and concentration of vacancies containing clusters and dislocation loops. The results also explain the long hardness plateau observed previously in ageing experiments carried out between 100 and 240°C in terms of a continuous growth of Mg-Cu-vacancy clusters during ageing. The vacancy concentration of the clusters increases gradually until the setting in of the cluster Guinier-Preston-Bagaryatsky zone transformation.  相似文献   
90.
In this study, we investigate the interrelationship between clinical variables and working memory (WM) in Parkinson’s disease (PD). Specifically, the aim of the study was to investigate the relationship between disease duration, dopaminergic medication dosage, and motor disability (UPDRS score) with WM in individuals with PD. Accordingly, we recruited three groups of subjects: unmedicated PD patients, medicated PD patients, and healthy controls. All subjects were tested on three WM tasks: short-delay WM, long-delay WM, and the n-back task. Further, PD encompasses a spectrum that can be classified either into akinesia/rigidity or resting tremor as the predominant motor presentation of the disease. In addition to studying medication effects, we tested WM performance in tremor-dominant and akinesia-dominant patients. We further correlated WM performance with disease duration and medication dosage. We found no difference between medicated and unmedicated patients in the short-delay WM task, but medicated patients outperformed unmedicated patients in the long-delay WM and n-back tasks. Interestingly, we also found that akinesia-dominant patients were more impaired than tremor-dominant patients at various WM measures, which is in agreement with prior studies of the relationship between akinesia symptom and basal ganglia dysfunction. Moreover, the results show that disease duration inversely correlates with more demanding WM tasks (long-delay WM and n-back tasks), but medication dosage positively correlates with demanding WM performance. In sum, our results show that WM impairment in PD patients depend on cognitive domain (simple vs. demanding WM task), subtype of PD patients (tremor- vs. akinesia-dominant), as well as disease duration and medication dosage. Our results have implications for the interrelationship between motor and cognitive processes in PD, and for understanding the role of cognitive training in treating motor symptoms in PD.  相似文献   
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