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1.
Thermal effects on the energy absorption efficiency of a system consisting of hydrophobic mesoporous silica particles immersed in water have been investigated. As the temperature increases, although the infiltration pressure decreases only slightly and the accessible pore volume remains nearly constant, the system recoverability can be significantly improved, primarily due to an increase in outflow pressure. The sequence of changing pressure and temperature has little influence on the system performance.  相似文献   

2.
Aluminium (Al) nanoparticles (NPs) have been successfully fabricated on a liquid surface by thermal evaporation at room temperature. The Al NPs exhibit a disc-shaped morphology with mean diameter and height in the ranges 20–35 and 1.3–3.7?nm, respectively. As the nominal film thickness increases from 0.02 to 0.18?nm, the mean diameter and height are nearly independent of the thickness, implying that the density of the NPs increases during their growth. An explanation for this phenomenon is presented.  相似文献   

3.
Germanium has been processed by high-pressure torsion (HPT) under a nominal pressure of 24 GPa at room temperature and cryogenic temperature. The samples processed at room temperature were composed of a diamond-cubic Ge-I phase and a metastable tetragonal Ge-III phase. The formation of Ge-III was significantly suppressed and Ge-I and an amorphous phase, in addition to a small amount of body-centred-cubic Ge-IV, appeared in the case of cryogenic HPT processing at 100 K. The Ge-IV phase gradually disappeared at room temperature. These results indicated that shear strain and thermal energy are important for promoting the formation of Ge-III.  相似文献   

4.
The complete high-order perturbation formulae of spin-Hamiltonian (SH) parameters (g factors gi and hyperfine structure constants Ai , where i = x, y, z) containing contributions from both the crystal-field (CF) and charge-transfer (CT) mechanisms (the latter mechanism is neglected in the widely-used CF theory) are established for d1 ions in rhombic tetrahedra. From these formulae, the SH parameters of Cr5+ ion at the rhombically-distorted tetrahedral P5+ site of Ca2PO4Cl crystal are calculated. The CF and CT energy levels used in the calculation are obtained from the optical spectra of the studied Ca2PO4Cl : Cr5+ crystal. The calculated results showed reasonable agreement with the experimental values. The signs of the hyperfine structure constants Ai and the relative importance of the CT mechanism to SH parameters are acquired from the calculations.  相似文献   

5.
The proportion of plastic bottles that consumers placed in appropriate recycling receptacles rather than trash bins was examined across 3 buildings on a university campus. We extended previous research on interventions to increase recycling by controlling the number of recycling receptacles across conditions and by examining receptacle location without the use of posted signs. Manipulating the appearance or number of recycling bins in common areas did not increase recycling. Consumers recycled substantially more plastic bottles when the recycling bins were located in classrooms.  相似文献   

6.
Abstract

The ability of amorphous metallic alloys to resist irradiation-induced structural changes will depend on the composition of the alloy and the particle fluences used. In this paper we show that a fast neutron fluence of 1020 cm?2 can induce local crystallization in a refractory NiTi glass. For specimens irradiated with lower fluences, the mode of crystallization of the amorphous matrix is changed from that of a primary process to a eutectic mechanism.  相似文献   

7.
Humans were used to investigate changes in response force occurring soon after reinforcement was eliminated. In Experiment 1, in a 300-s baseline phase, 10 participants received a point for holding down a pressure sensor set to operate at a force equal to 85% of the maximum force the participants exerted during a pretest. Following this, during a 600-s extinction phase, criterion responses had no consequence. In Experiment 2, 6 participants worked on the same task, but (a) points were exchangeable for money and (b) after extinction, the reinforcement baseline phase was reinstated. In Experiment 3, 6 participants completed the same task as in Experiment 2, but the required minimum force was 60% of the maximum force exerted during the pretest. In each experiment, increases in response force relative to the mean and peak force exerted during the last 100 s of baseline were observed in most participants when force responses were aggregated into short sample intervals, but less so with longer ones. The increases, however, were not systematic across or within participants, questioning the generality of and the criteria for demonstrating an extinction burst.  相似文献   

8.
Children in Head Start are at risk for school learning or behavioral problems. While Head Start has decreased special education placement, there has been little systematic data until recently on identification of children in disability categories following preschool. In this study, two cohorts of 6,162 children across 30 sites were followed through third grade. Approximately half of these children were provided transition assistance from kindergarten through third grade. This included school transition and curricular modifications, parent involvement activities, health screening or referrals, and family social services, all similar to those received in Head Start. They were compared to a similar group of Head Start children who did not receive such services beyond the Head Start experience. Special education eligibility was determined from school records in the spring of third grade. Only 0.89% of children in the transition group were identified in the mental retardation category compared to 1.26% in the non-transition group. In the category of emotional disturbance, these same figures were 1.21% and 1.65% respectively. Both differences were statistically significant, but an opposite effect was found in the category of speech or language impairment. Findings are discussed in relation to differences in disability categories and implications for early identification.  相似文献   

9.
ABSTRACT

The basic mechanisms governing the process of cracking of single-layer brittle films have been extensively explored through both simulations and experiments. However, the role that an adhesive interlayer plays in the cracking of the overlying brittle film remains unclear. By performing three-point bending experiments, we observed that the insertion of a 100?nm thick Ti interlayer changed the cracking behaviour of TiN films from a continuous pattern to a discontinuous pattern. The slight change in the microstructure of the film and the increase in film thickness arising from the addition of the Ti interlayer are unlikely to cause the observed cracking morphology. The combination of the different interface between the Ti and the steel substrate and the fracture of the Ti interlayer are responsible for the transition in the TiN film cracking morphologies.  相似文献   

10.
This study investigated the effects of a teaching and modeling intervention on the development of early reciprocity and maternal self-confidence between black low-income primiparous mothers and their newborn infants. The sample included 20 mothers who had an uneventful pregnancy, labor, delivery, and postpartum course. Infants were healthy, full-term, singleton, and bottle-fed. Mothers in the experimental group received a teaching session in which the investigator discussed and modeled caregiver behaviors which elicit interactive behaviors and skills of the infant. State control, response to stress, motoric processes, and interaction processes were discussed. On pretest, no significant differences were found between the control and experimental groups on any variable. At posttest, statistically significant differences were found between the two groups on assessment of the mother-infant sensitivity scale. No significant differences were found between the treatment and the control groups on the Mother's Assessment of the Behavior of her Infant (MABI) or the Self-Confidence scores.  相似文献   

11.
We investigated whether personality moderates group influence of classmates on academic achievement and whether these so-called context effects can be attributed to peer pressure. The sample consisted of 2498 students in their first year of Dutch secondary education. The data were analyzed by a two-level (students within classes) analysis, separately for boys (n = 1033, in 92 classes) and girls (n = 1465, in 119 classes). For both sexes, we found a context effect on Dutch language achievement but not on mathematics achievement. Emotional Stability appeared a moderator of this context effect but for girls only. The results suggest further that peer pressure is not a likely mechanism of group influence of classmates on academic achievement.  相似文献   

12.
The effects of a career course taught by 11 instructors (two sections each) for college students, who were undecided about a major field or career, were evaluated in a pre-post design using the Vocational Identity, Occupational Information, and Barrier scales of the My Vocational Situation (J. A. Holland, D. C. Daiger, & P. G. Power, Palo Alto, Calif.: Consulting Psychologists Press, 1980). Large main effects were observed for the Identity and Occupational Information scales, but not for the Barriers scale. No interactions by instructor or student characteristics were found by using a simple ANOVA procedure or by using a split plot factorial design. The implications for new research and career instructors were discussed.  相似文献   

13.
In 2008, nearly 31% of vehicle fatalities were related to failure to adhere to safe vehicle speeds (National Highway Traffic Safety Administration [NHTSA], 2009). The current study evaluated the effect of a rectangular rapid-flashing beacon (RRFB) triggered by excessive speed on vehicle speed using a combined alternating treatments and reversal design. The percentage of vehicles traveling above 41 mph (66 km per hour) decreased by 20%, and speed distributions showed a shift toward lower speeds during the RRFB condition.  相似文献   

14.
Five groups of three subjects resided for 10 or 15 days within a continuously programmed environment. Subjects followed a programmatic arrangement of required and optional private and social activities that determined the individual and group baseline behaviors into which experimental operations were introduced and withdrawn. A cooperation condition was in effect when all three subjects were required to select simultaneous access to a group area before it became available for use. A noncooperation condition was in effect when access to a group area could be selected by individual subjects, without regard to the other subjects' selections. For all groups, the effects of these two conditions on individual and group behaviors were investigated in reversal designs where several successive days occurred under each condition. Groups 1, 4, and 5 had the noncooperation condition interposed between cooperation conditions. Groups 2 and 3 had the cooperation condition interposed between noncooperation conditions. Durations of triadic activities, per cent of time in triadic activities, intercom use, and intersubject program synchronization were greater during cooperation conditions than during noncooperation conditions. These data show that a cooperation contingency within the behavioral program affected both social behavior and the collateral individual behavior necessary to execute the cooperation response.  相似文献   

15.
16.
The phase field method is frequently employed to simulate evolution of rather complex microstructures. In order to accurately describe the real kinetics of a specific material system, the phase field parameters must be calibrated to standard thermodynamic quantities such as interface mobilities or interface energies. This letter presents a convenient method, based on thermodynamic modelling of shrinking of a single grain embedded in single crystal (matrix), how to calibrate the phase field parameters. It also shows, how the required thermodynamic quantities can be met by proper rescaling of a phase field simulation carried out for given phase field parameters.  相似文献   

17.
We examined how a friend's presence affects a performer's prefrontal activation in daily‐life activities using two wireless portable near‐infrared spectroscopy (NIRS) devices. Participants played a driving video game either solely in the single group or with a friend in the paired group. The two groups (single and paired) were subdivided according to their game proficiency (low and high). The NIRS data demonstrated a significant interaction of group by proficiency. Low‐proficiency players in the paired group showed lower activation than those in the single group, but high‐proficiency players did not. In the paired group, high‐proficiency players showed higher activation than low‐proficiency players, but not in the single group. These results suggest that NIRS detects social presence effects in everyday situations: decreasing prefrontal activation in low‐proficiency performers due to tension reduction and increasing prefrontal activation in high‐proficiency performers due to increased arousal.  相似文献   

18.
College students were instructed to press a button for points under a single reinforcement schedule or under a variety of reinforcement schedules. Instructions for a single schedule were either specific or minimal. Instructions on a variety of schedules involved specific instructions on eight different schedules of reinforcement. Subsequent to the varied training, responding under a fixed-interval schedule occurred at a low rate. Both the minimal and specific instruction training led to fixed-interval responding that was similar to the responding exhibited during training. These findings suggest that under certain conditions instructed behavior is sensitive to changes in contingencies.  相似文献   

19.
GaN photonic crystal slabs on InGaN/GaN multi-quantum well light-emitting diodes have been formed by dry etching using nanoporous anodic alumina templates, which have a periodic lattice constant of 105 nm and a hole diameter of 45 nm. The photonic crystal slab shows an enhanced intensity of photoluminescence due to the nanohole pattern array producing Fabry–Perot like interference. A rough surface of nanoholes results in a broad spectrum with a small oscillation, and well-ordered multiple facets of nanoholes results in a relatively sharp spectrum with a large oscillation.  相似文献   

20.
Background and objectives: Mindfulness meditation (MM) training promotes health and well-being. One potential mechanistic link between MM and health may be coping flexibility, (e.g., the ability to monitor and modify coping strategies based on situational needs and strategy effectiveness). We hypothesized that MM training would increase coping flexibility and also explored whether gains in coping flexibility continued to increase after training, or whether they were maintained or lost with time.

Methods and design: One hundred thirteen students (71 female, Mage?=?18.97) were randomly assigned to a waitlist control or MM condition. Participants in the MM condition were trained by a certified MM instructor and given guided recordings for one-week of at-home practice. Participants provided reports of coping flexibility over a three-week span.

Results: Results from multilevel modeling indicated that MM increased coping flexibility among those in the MM condition and among those who spent relatively more time meditating. Results further suggested that the gains in coping flexibility that were evident at post-test were not only maintained but increased in the two weeks after the intervention.

Conclusions: This study provides preliminary support for the assertion that MM increases the ability to monitor and modify coping strategies during times of stress.  相似文献   


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