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241.
The effect of chemical stresses upon the relation between extended dislocations and high-temperature creep in a thin plate has been investigated. The critical stress needed for the contraction of extended jogs and its effect on the creep rate are obtained. The results indicate that the critical stress needed for the contraction increases with decreasing stacking fault energy (SFE). However, creep occurs more easily with increasing SFE and increasing angle of the Burgers vector to the dislocation line, as well as with the concentration of any diffusing atoms.  相似文献   
242.
FeNi with the L10-ordered structure is formed over an astronomical timescale in meteorites. In this study, severe plastic deformation using high-pressure torsion (HPT) is employed for the production of the L10 structure in the laboratory. Its formation is confirmed by X-ray diffraction analysis and transmission electron microscopy. Processing of elemental nanopowders by HPT is an effective method for the formation of the L10 phase, which is enhanced by the addition of Co to FeNi or annealing after HPT. The formation of the phase must be associated with enhanced diffusion through HPT.  相似文献   
243.
This article describes the influence of microstructure on the dielectric and piezoelectric properties of isovalent- donor- and acceptor-modified lead lanthanum zirconium titanate (PLZT) ceramics. The ceramic compositions, with formula: [Pb0.954La0.016Ba0.01Sr0.02][Zr0.525Ti0.475]0.981?( m /2)Nb0.012Zn m O3 where m =?0, 0.2, 0.4, 0.6, 0.8 and 1.0 mol% Zn, were synthesized via a solid-state reaction method. X-ray diffraction studies are supported by tolerance factor and electronegativity difference measurements. Scanning electron microscopy studies reveal grain growth enhancement with increase of Zn concentration. As the Zn concentration increased from 0 to 0.8 mol%, the room-temperature dielectric constant increased while the Curie temperature decreased continuously. An increase in the Zn content had the most significant effect on the piezoelectric properties. The optimum piezoelectric properties were observed for 1 mol% Zn composition.  相似文献   
244.
In ‘What Luck Is Not’, Lackey presents counterexamples to the two most prominent accounts of luck: the absence of control account and the modal account. I offer an account of luck that conjoins absence of control to a modal condition. I then show that Lackey's counterexamples mislocate the luck: the agents in her cases are lucky, but the luck precedes the event upon which Lackey focuses, and that event is itself only fortunate, not lucky. Finally I offer an account of fortune. Fortune is luck-involving, and therefore easily confused with luck, but it is not itself lucky.  相似文献   
245.
246.

Objective

A previous randomised controlled trial demonstrated that a cognitive behavioural therapy (CBT) self-management intervention significantly improved irritable bowel syndrome (IBS) symptoms and disability compared to treatment as usual (TAU). The current study analysed additional data to establish whether; 1) cognitive, behavioural and emotional factors hypothesized to perpetuate IBS symptoms and disability changed following CBT and, 2) ascertain if changes in these factors over the intervention period mediated treatment effects 6-months later.

Method

IBS patients (CBT = 31, TAU = 33) completed measures pre-and-post intervention including: Brief Illness Perception Questionnaire, Hospital Anxiety & Depression Scale and Cognitive and Behavioural Responses to Symptoms Questionnaire. Path models were evaluated to determine whether changes in cognitive and behavioural factors over the treatment period mediated treatment effects.

Results

Compared to TAU, CBT patients showed significant positive changes on several cognitive variables but not anxiety and depression following intervention. Positive change in illness perceptions following intervention mediated the treatment effect on improved IBS symptom severity and social adjustment six months later. Changes in damaging beliefs mediated the effect on social adjustment.

Conclusions

Change in cognition rather than mood mediated treatment related improvements. Changing negative perceptions of IBS appears to be a particularly important treatment mechanism.  相似文献   
247.
The burden of HIV disease is concentrated in sub-Saharan Africa, particularly in South Africa (SA). Whilst there have been many studies conducted on the biomedical and socio-psychological aspects of HIV and AIDS, insufficient attention has been paid to the quality of life of those infected with the virus. The primary purpose of the study was to determine the predictors of quality of life enjoyment and satisfaction (Q-LES) among individuals infected with HIV. A battery of questionnaires, which included the Hospital Anxiety and Depression Scale (HADS) and the Quality of Life Enjoyment and Satisfaction Questionnaire (Q-LES-Q), were administered to 121 participants. Data was analysed using SPSS. Of the total sample (n = 121), 74% were females. The study found that a large proportion (49.5%) of the sample within the age group 25–49 years old experienced psychological distress. Those who were not on antiretroviral treatment (ART) were significantly affected (66%). Psychological distress was significantly prevalent among HIV positive individuals and also the strongest predictor of Q-LES among these individuals.  相似文献   
248.
249.
The purpose of this scoping literature review was to identify trends regarding validity, value and veracity issues when conducting (qualitative) interviews with offenders in custodial settings. We selected for review works from electronic databases in SAGE, Springer, and Taylor and Francis by using e-journals, Google Scholar and the behavioural science database, PsycINFO. The inclusion criteria for our studies were based on whether sources addressed offender interviewing as a wellspring of information, but excluded those that focused solely on the acquisition of clinical information (at the expense of focusing on validity, value and veracity issues). We utilised the content analysis approach to identify themes/ patterns in the research findings. Key findings suggest that offenders with impression management motivations deceive and manipulate in their research interview presentations. When gathering data from inmates in custodial care settings, best practice includes cross-checking offender interview data against other sources of evidence and taking into account the context in which they are serving their sentences.  相似文献   
250.
Self-regulation (SR), an important construct within the psychological well-being context, involves the ability to monitor behaviour, to contrast it with reference values and to introduce adjustments where necessary. A lack of validated measures of SR in the South African context has contributed to the current caveat in our knowledge of the potential importance of this construct. This investigation aimed to establish the utility of the Short Self-Regulation Questionnaire (SSRQ; Carey, Neal & Collins, 2004) in a South African context. This short version of the original Self-Regulation Questionnaire (SRQ; Brown, Miller & Lawendowski, 1999) was completed by a group of 385 undergraduate psychology students. Factor analysis produced 7 factors, all of which showed significant positive correlations with other measures of psychological well-being. This first step toward establishing the importance of SR in non-Western cultures reflected positively on the potential use of the SSRQ in large epidemiological studies.  相似文献   
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