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排序方式: 共有365条查询结果,搜索用时 15 毫秒
31.
Crucial process modifications were shown necessary to improve the economics of cryogenic grinding of flexible polyurethane (PU) foam. It is concluded that foam densification prior to cryogenic processing was essential to reduce insulation effects. In comparative studies of foam and densified foam, increasing the density to ~800 kg/m3 resulted in dramatically reduced cryogen use and vastly improved output. Results indicated that cryogenic pulverization presents a significantly more economic solution than previously recognized. Particles produced by this method were added to foam formulations and effects of particle size and structure on compression properties and cell structure of resultant foams were studied. Particle sizes <100 μm gave similar compression properties and cell size to virgin foam at up to 10 parts by weight on 100 parts of polyol, but cell structure and compressive properties showed increasing divergence as particle size and addition concentration increased. Studies of alternative uses showed that the PU particles showed promise as fillers in rigid PU foam formulations and suggested an extending or reinforcing action in natural rubber vulcanizates. 相似文献
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Biomedical Applications: Endocytic pH‐Triggered Degradation of Nanoengineered Multilayer Capsules (Adv. Mater. 12/2014)
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34.
Seung-Hyun Kim Chang Young Koo Jinkee Lee Wenyan Jiang Angus I. Kingon 《Materials Letters》2011,65(19-20):3041-3043
High quality PZT thick films over 10 μm were successfully prepared using a chemical solution infiltration into the porous screen-printed PZT thick films. The hybrid films prepared with solution infiltration process showed very dense and uniform microstructure with large grain size at a low annealing temperature such as 700 °C. The hybrid films showed markedly enhanced electrical properties. The measured dielectric constant, the remanent polarization and the piezoelectric d33 coefficient of the films were 1900, 27 μC/cm2, and 230 pC/N, respectively, which were over two times higher than those of the screen printed films without the solution infiltration process. 相似文献
35.
Traditionally, the "happiness" of the American population has been measured in economic or objective terms. But research (A. Campbell et al, in press) indicates that between 1957 and 1972, while the economic and social indicators were rapidly moving upward, the proportion of the population who described themselves as "very happy" declined steadily, particularly among the most affluent portion of the population. It is argued that in order to describe the quality of the experience of the population, more subjective measures are needed to examine the experience itself. Three general measures of life experience (satisfaction with life, affective quality of life, and perceived stress) are discussed in terms of an earlier (1972) author-conducted study. Findings from that study indicate that while the 3 measures are moderately related to each, people living in different circumstances express different patterns of well-being and that these patterns reflect the peculiar quality of the situation in which they live. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
36.
Strange attractors in multipath propagation 总被引:1,自引:0,他引:1
The estimation of the correlation dimension of multipath propagation signals in an indoor environment, indicates the presence of a strange attractor of dimension between four and five, suggesting deterministic chaos. The authors stress that although the profiles they examined show saturation in all three experimental configurations, indicating that they would be able to describe their data with a set of at most five nonlinear differential equations, investigation in other propagation situations is needed. An example of the detection of the presence of strange attractors in radar clutter is presented 相似文献
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Doane Jeri A.; Miklowitz David J.; Oranchak Erik; Flores de Apodaca Roberto; Karno Marvin; Strachan Angus M.; Jenkins Janis H. 《Canadian Metallurgical Quarterly》1989,98(4):487
Levels of parental communication deviance (CD), as measured on the Thematic Apperception Test (TAT), were compared among families of schizophrenic patients in two culturally distinct groups. Spanish-speaking Mexican-American parents of schizophrenics completed the TAT in their native language, and CD was coded from their stories by a Spanish-speaking rater. Mexican-American parents had levels of CD that were nearly identical to those of a carefully matched sample of English-speaking Anglo-American parents. Factor scores that measure distinct subtypes of CD also did not differ across groups. The data suggest that levels of CD, despite discriminating between parents of schizophrenics and nonschizophrenics, do not vary across different languages and cultures. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
40.
Formulas and procedures are given for calculating item and test means, variances, intercorrelations, and item-selection indices on the basis of an 'F-matrix' that shows the number passing every pair of items. If IBM equipment is not available to develop the F-matrix, alternate procedures based on hand sorting are recommended and described. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献