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271.
The Ti36Ni41Hf15Cu8 melt-spun ribbon undergoes a B2 ? B19′ transformation upon cooling and heating. When the Ti36Ni41Hf15Cu8 melt-spun ribbon is annealed at 873 K for 1 h, the spherical (Ti, Hf)2Ni particles with a diameter of 20–40 nm precipitate in the grain interior. The fine (Ti, Hf)2Ni precipitates improve the stability of phase transformation temperatures and cause martensite domains, with (001) compound twins in three orientations dominant instead of (011) type I twins. {111}-, {113}- and (001)//{111}-type boundaries are observed among these martensite domains. When the (Ti,Hf)2Ni precipitates coarsen, (011) type I twins become main martensite structures in the ribbon annealed at 973 K for 1 h. 相似文献
272.
Single Al-Pd-Re icosahedral quasicrystals with a maximum diameter of 5mm have been grown by a slow cooling method on the basis of a partial phase diagram determined in the present study. Laue X-ray and electron diffraction verified the highly ordered structure of the single icosahedral quasicrystals. The electrical resistivity rho of the single quasicrystals was measured to be 2000- 4000muOmegacm at 300K and 3000-6000muOmegacm at 2K, revealing a negative temperature dependence with a rho4.2K/rho300K value smaller than 2. 相似文献
273.
The structures of the binary ZrCr2 and ZrCr2 Laves phase with addition of V have been investigated by high-resolution transmission electron microscopy (HRTEM). The results show that annealed ZrCr2 is the cubic C15 phase with micro-twins. In contrast, annealed Zr(CrV)2 has a lamellar microstructure with a character of long-period stacking sequences. Further studies by HRTEM indicate that annealed Zr(CrV)2 is the di-hexagonal C36 with a coalescence of 5-, 6- and 8-layer long-period stacking structures. The effect of V addition on the structural stability of ZrCr2 is discussed. 相似文献
274.
Composition formulae for alloy phases are developed using first-neighbour coordination polyhedra plus their connections. The resultant cluster formulae [cluster](glue atom) x , similar to molecular formulae for chemicals, contain key structural and composition information on the alloy phases. As examples, Al–Ni–Zr alloy phases are analysed with the objective of revealing cluster formula properties such as the principal cluster, the cluster phase and the definition of complex alloy phases. 相似文献
275.
Two Fe–Cu binary model alloys, Fe–0.3Cu and Fe–0.6Cu, were irradiated with fission neutrons at doses ranging from 4?×?10?6 to 0.16 dpa (displacements per atom) at ~573 K to investigate the formation of Cu precipitates and microstructural evolution. The Cu content only affected the formation of Cu precipitates and microvoids at low doses. In Fe–0.3Cu, the formation of microvoids and Cu precipitates initiated at doses of 1.2?×?10?4 and 4?×?10?5 dpa, respectively. On the other hand, the formation of microvoids started at a dose of 4?×?10?4 dpa in Fe–0.6Cu, and Cu precipitates were formed even after irradiation to 4?×?10?6 dpa. On further irradiation, the difference in the formation of Cu precipitates and microvoids was small. Microvoids grew with increasing irradiation dose up to 3?×?10?3 dpa in both alloys. Prominent aggregation of Cu atoms occurred upon irradiation from 3?×?10?3 to 1.6?×?10?2 dpa and the microvoids shrank. The Cu precipitates no longer grew, and microvoids nucleated and grew in the matrix above a dose of 1.6?×?10?2 dpa in both alloys. The present studies clearly reveal the relationships between the formation and growth of Cu precipitates and microvoids with irradiation dose. 相似文献
276.
277.
This investigation demonstrates that emotion regulation can be driven by considerations of utility per se. We show that as participants prepared for a negotiation, those who were motivated to confront (vs. collaborate with) another person believed that anger would be more useful to them. However, only participants who were motivated to confront another and expected to receive a monetary reward for their performance (i.e., high utility), were motivated to increase their anger in preparation for the negotiation. Participants who were motivated to confront another but did not expect their performance to be rewarded (i.e., low utility), did not try to increase their anger, even though they expected anger to be useful in the negotiation. Such patterns demonstrate that people are motivated to experience even unpleasant emotions to maximise utility. 相似文献
278.
Existing models of trauma suggest that for recovery to occur, trauma related cues and emotions require awareness and openness while survivors continue committing action toward valued life aims (other than regulating emotions). Based on this theoretical framework, an unwillingness to be in contact with distressing thoughts and feelings (experiential avoidance) might operate together with posttraumatic distress to predict when people find benefits and meaning in the aftermath of trauma. We hypothesized that people reporting posttraumatic distress and less reliance on experiential avoidance would report greater posttraumatic growth and meaning in life compared with other trauma survivors. We administered questionnaires to 176 college students reporting at least one traumatic event. Results supported these moderation models. This is the fourth study (with different samples, measures, and methodologies) to provide evidence that a combination of excessive anxiety and a heavy reliance on experiential avoidance leads to attenuated well-being. We discuss the implications for understanding heterogeneous trauma reactions. 相似文献
279.
Pfordresher PQ Keller PE Koch I Palmer C Yildirim E 《Psychonomic bulletin & review》2011,18(3):544-549
The present research addressed whether auditory feedback associated with a learned action sequence can activate the action
representation of that sequence. Nonpianist participants learned to perform two melodies at a piano keyboard repeatedly during
a trial. The participants heard feedback either from the melody they were performing (normal feedback) or from the other learned
melody (termed alternate feedback). An additional tone functioned as an instruction cue to either switch melodies or continue the current melody.
Following the instruction cues, participants typically paused just before switching, and paused similarly during trials with
a continue cue. Participants paused longer after a continue cue when they experienced alternate rather than normal feedback.
This effect was specific to instruction cues positioned at weak metrical accents—positions at which participants were less
likely to switch overall. Feedback did not influence timing on switch trials. These findings indicate that influences of auditory
feedback can activate learned action sequences, leading to longer latencies associated with cue evaluation. 相似文献
280.
Interference with cholinergic functions in hippocampus and prefrontal cortex impairs learning and memory for social transmission of food preference, suggesting that acetylcholine (ACh) release in the two brain regions may be important for acquiring the food preference. This experiment examined release of ACh in the hippocampus and prefrontal cortex of rats during training for social transmission of food preference. After demonstrator rats ate a food with novel flavor and odor, a social transmission of food preference group of rats was allowed to interact with the demonstrators for 30 min, while in vivo microdialysis collected samples for later measurement of ACh release with HPLC methods. A social control group observed a demonstrator that had eaten food without novel flavor and odor. An odor control group was allowed to smell but not ingest food with novel odor. Rats in the social transmission but not control groups preferred the novel food on a trial 48 h later. ACh release in prefrontal cortex, with probes that primarily sampled prelimbic cortex, did not increase during acquisition of the social transmission of food preference, suggesting that training-initiated release of ACh in prelimbic cortex is not necessary for acquisition of the food preference. In contrast, ACh release in the hippocampus increased substantially (200%) upon exposure to a rat that had eaten the novel food. Release in the hippocampus increased significantly less (25%) upon exposure to a rat that had eaten normal food and did not increase significantly in the rats exposed to the novel odor; ACh release in the social transmission group was significantly greater than that of the either of the control groups. Thus, ACh release in the hippocampus but not prelimbic cortex distinguished well the social transmission vs. control conditions, suggesting that cholinergic mechanisms in the hippocampus but not prelimbic cortex are important for acquiring a socially transmitted food preference. 相似文献