22 resultados para internal and external efficiency


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Internal and surface waves generated by the deformations of the solid bed in a two layer fluid system of infinite lateral extent and uniform depth are investigated. An integral solution is developed for an arbitrary bed displacement on the basis of a linear approximation of the complete description of wave motion using a transform method (Laplace in time and Fourier in space) analogous to that used to study the generation of tsunamis by many researchers. The theoretical solutions are presented for three interesting specific deformations of the seafloor; the spatial variation of each seafloor displacement consists of a block section of the seafloor moving vertically either up or down while the time-displacement history of the block section is varied. The generation process and the profiles of the internal and surface waves for the case of the exponential bed movement are numerically illustrated, and the effects of the deformation parameters, densities and depths of the two layers on the solutions are discussed. As expected, the solutions derived from the present work include as special cases that obtained by Kervella et al. [Theor Comput Fluid Dyn 21:245-269, 2007] for tsunamis cased by an instantaneous seabed deformation and those presented by Hammack [J Fluid Mech 60:769-799, 1973] for the exponential and the half-sine bed displacements when the density of the upper fluid is taken as zero.

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It is well established that memory functioning deteriorates with advancing age. However, research indicates that the magnitude of age-related memory deficits varies across different types of memory, and broad individual differences can be observed in the rate and timing of memory aging. The general aim of this study was to investigate the selectivity and variability of memory functioning in relation to anxiety. Firstly, memory effectiveness was assessed in episodic memory tasks with reality monitoring and external source monitoring paradigms, semantic memory tasks referred to general knowledge and word fluency, and perceptual priming task reflected in word completion. According to the scores on trait version of STAI, the high-trait and low-trait anxious subjects were screened respectively from young and old participants matched for educational level. Secondly, based on the results of the first part, concurrent primary and secondary tasks with probe technique assessing spare processing capacity were used to explore the relation between memory efficiency and anxiety. The first main findings were that: (a) there were no age-related differences in semantic memory assessed by general knowledge and PRS, whereas age effects were observed in episodic memory and semantic memory assessed by word fluency with stringent time restraints. (b) Furthermore, comparison of age-related deficits in source and item was not related to the presentation ways and encoding effort for source, but was affected by types of source. Specifically, memory was more sensitive to aging than item memory in external source monitoring processes involved in discriminating two external sources (i.e., female vs. male voices), but not in reality monitoring processes in discriminating between internal and external sources (i.e., acting vs. listening). The second main findings were that: (a) Anxiety had no effects on the effectiveness and efficiency of semantic memory in recall of general knowledge and PRS, but impaired those of semantic memory in word fluency. (b) The effects of anxiety on episodic memory were different between the old and the young. Both the effectiveness and the efficiency of episodic memory of the old were affected adversely by anxiety. More importantly, source recall in external source monitoring processes was observed to be more vulnerable to anxiety than item memory. The effectiveness of episodic memory of the young was relatively unrelated to anxiety, while anxiety might have adverse effect on their memory efficiency. These results indicated that: First, the selectivity of age-related memory deficits existed not only between memory systems, but also within episodic memory system. The tendency to forget the source even when the fact was retained in external source monitoring was suggested to be a specific feature of cognitive aging. Second, anxiety had adverse impact on the individual differences in memory aging, and mediated partial age-related differences in episodic memory performance.

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genetics, such as: population size, reproduction, mating system, growth, development,genetic structure and systematics status; The main results are presented below: The seasonal variation of the operational sexual ratio of this animal was found in the field and the ration always bias the female in the breeding season. Aiming at this character and considering the distance of time and space of both sexual habitat in breeding season, we census female population first by toe-clipping mark-recapture method, then estimated the population size with the definitive sexual ratio. Up to now, this species was found only at the Beilun district of the Ningbo City. The population size of the Ruiyan Temple Forest Park approximates to 369. The status of this population is extremely endangered, so besides protecting this population at the original locality, we also suggested to breed the salamander in fenced locality and to hatch embryos artificially, and send metamorphosed juveniles back to nature. We can transfer some individuals to other similar habitats or breed them under artificial conditions for saving this species from extinction. The early developmental stage of the Chinhai salamander is the same as its relative species, E. andersoni. Their balanceres are poorly developed and disappear very early. Temperature and moisture significantly influence the embryonic development of the Chinhai salamander. The embryonic stage is approx. 29 days under room temperature. The hatchling grows in a logarithmic curve. The larvae stage in water is approx. 58- 88 days. Many factors influence the nomal development, including two aspects of internal and external. Due to these factors, the effective protected measures were presented in detail. The breeding migration of E. chinhaiensis takes place at late March~late April every year. This salamander's hatching rate is high, but the rate of hatchling migrating into water is low. The average effectiveness of all the nest sites is 36.7%. The maternal self-conservation was contrary to the reproductive success of the egg-laying strategy. In the strategy of egg-laying behavior, the first factor selected by the female was its self-conservation, the second is embryonic survival rate, and the last is rate of hatchling survival rate. The oviposition selection is significant for the survival of the larvae. Based on the analysis of the evolutionary process of reproductive behaviors nad egg-laying site selections of all genera of the family Salamandridae, we deduced that perhaps Echinotriton is a transitional type in the evolutionary process from water to land. Due to its location in the adaptive stage in the terrestrial evolution, Echinotriton chinhaiensis's terrestrial nest may be one of important reason that causes this species to be endangered. The genetic deversity analysis shows that although the population size of the Chinhai salamander is quite small compared to other Chinese salamandrid species, the genetic diversity of this population is not reduce remarkably. We explain this phenomena with the polygamy mating system of this species. The result of 4 families' parenthood determinations shows that the parenhood determination can be taken without any paternal information. The "children" of every female include rich genetic information from at least two "fathers". It implies that female Chinhai salamander mates more than once with different males in a breeding season. The molecular evidence, the behavioral observation evidences and the sperm evidence in the female cloaca proved that this species has a polygamy mating system. The kin recognition in the mating of adult salamander was first discussed. The taxonomic status and phylogenetic relationships of 12 species representing 6 genera in the family Salamandridae were studied using DNA fingerprinting. The results showed that the DNA fingerprinting. The results showed that the DNA fingerprinting patterns demonstrated rich genetic diversity and species diversity, and also revealed the taxonomic status and phylogenetic relationshipes of higher taxa to a certain extent. The results are highly consistent with those obtained from the studies based on the morphology, ecology, cytology and molecular biology. The compreshensive analysis indicate that Tylototrition hainanensis and T. wenxianensis should be valid species; Echinotriton should be a valid genus;Tylotortriton is a natural cluster; Tylotortriton asperrimus should be put in Tylototrition rather than in Echinotriton, Hypselotriton and Allomestriton are synonyms of Cynops and Paramesotriton, respectively. There are three main groups in Chinese salamandride: Cynops, Paramesotriton and Pachytrition from the first group, the species of the Tylototriton from the second, and E. chinhaiensis composes the third.

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Cellulose hollow fiber membranes (CHFM) were prepared using a spinning solution containing N-methylmorpholine-N-oxide as solvent and water as a nonsolvent additive. Water was also used as both the internal and external coagulant. It was demonstrated that the phase separation mechanism of this system was delayed demixing. The CHFM was revealed to be homogeneously dense structure after desiccation. The gas permeation properties of CO2, N-2, CH4, and H-2 through CHFM were investigated as a function of membrane water content and operation pressure. The water content of CHFM had crucial influence on gas permeation performance, and the permeation rates of all gases increased sharply with the increase of membrane water content. The permeation rate of CO2 increased with the increase of operation pressure, which has no significant effect on N-2, H-2, and CH4. At the end of this article a detailed comparison of gas permeation performance and mechanism between the CHFM and cellulose acetate flat membrane was given. (C) 2003 Wiley Periodicals, Inc.

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:本文从信息时代对人们认识上的影响,讨论了信息时代对生产、对统一的世界市场、对社会的影响。列举了世界经济进入新的繁荣期的特征。讨论了世界生产的形成和发展,市场竞争的三准则,市场竞争的各个历史阶段及全球化敏捷制造体系迅速发展的原因。分析了二十一世纪制造业面临的形势。详细地讨论了我国国有大中型企业的主要问题:1.产品问题;2.企业结构不合理;3.管理问题;4.质量问题;5.工艺手段和装备落后;6.历史包袱沉重等。提出了利用世界全球化生产体系发展的大好形势的三条对策:1.利用敏捷制造原理对企业进行重组;2.加速产品设计队伍的重建,增强新产品的设计能力;3.利用现代化手段实现现代化管理。

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The variations in structure and acidity on the internal and external surfaces of HY zeolites modified by MgO and SiO2 have been studied by MAS NMR, together with the selective adsorption of perfluorotributyl-amine. Al-27 and Si-29 MAS NMR spectra revealed that the modifications led to significant changes of the framework owing to the migration of some non-framework Si and Al into the framework in the course of the modifications. H-1 MAS NMR spectra showed that the modifications decreased the acidity of the zeolite surfaces. With an increasing of the loading of the oxides, the acidity of the surface decreased further. Both of the two kinds of Bronsted acidity of the MgO-modified HY zeolites decreased, particularly those in the supercages, while those of the SiO2-modified HY zeolites decreased less, and this result is consistent with that of NH3-TPD, from the adsorption of perfluorotributyl-amine, it was found that the acidic sites on the external surface of the HY zeolite can be completely covered by SiO2 after being modified by the chemical liquid deposition (CLD) method.

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The arguments on self discrepancy can be traced back to the old ages, but the systematic investigations were started by Higgins et al. at 1985.Compared to the large number of foreign studies, only a few ones have been conducted in our own country. Numerous characteristics of undergruaduate’s actual-ideal discrepancy and a great many determinative factors have been found as well as many of its negative effects—especially the greater the actual-ideal discrepancy, the more negative on the mind and behavior. Nevertheless, there are still many issues to be solved, such as the extend of the undergruaduate’s actual-ideal discrepancy level in own country. On the other hand, although there are a great many internal and external determinative factors of actual-ideal discrepancy, how they overally influence the discrepancy of the same individual is still unknown; to what extent does actual-ideal discrepancy influence the human mind and behavior and whether the influence is positive or negtive? This research collected a sample consisting of 4 undergraduate grades and 5 majors from a middle-ranked university. We adopted questionnaires in the study, and analyzed the data using correlation analysis, regression analysis, variances analysis, and path analysis. Our aim focused on the general characteristics of the undergruaduate’s actual-ideal discrepancy in own country, the overall working mechanism of the determinative factors including environmental and personal factors on the actual-ideal discrepancy of the same individual, and the effects of the actual-ideal discrepancy on psychological adaption, motivation, and behavior. The main results are as following: (1)The improved measurement instrument possesses good validity and reliability, and can be used in future research. (2) The actual-ideal discrepancy level among undergraduates is slightly bellow medium. The proportion of undergraduates who have a higher actual-ideal discrepancy level is small. There is significant gender difference in actual-ideal discrepancy level, but no significant difference across different majors and grades. (3)This research probed the overall working mechanism of the parenting style(environmental factors) and the personality factors(personal factors) including stability, flexibility, cleverness, and esteem on the undergruaduate’s actual-ideal discrepancy. The results shows that the parenting style of warmth and understanding, stability, flexibility, and esteem influence the actual-ideal discrepancy. Esteem entirely moderate the relationship between the parenting style of warmth and understanding and actual-ideal discrepancy, partially moderate the relationship between the flexibility, stability and actual-ideal discrepancy. Furthermore, the above factors can be order as stability, flexibility, and parenting style of warmth and understanding in terms of decreasing impact on the actual-ideal discrepancy. No significant effect of cleverness and other parenting style was found. The parenting style of warmth and understanding, stability, and flexibility interactively influence the actual-ideal discrepancy in the following manner: the stability and flexibility, both of which have independent influence on the actual-ideal discrepancy, entirely moderate the relationship between the parenting style of warmth and understanding and actual-ideal discrepancy. (4) Actual-ideal discrepancy plays a negative role in adaption indices, including self-efficacy, self-identity, self-actualization. Actual-ideal discrepancy also has negative effects on the 9 symptoms measured by SCL-90, vitality, approach motivation, avoidance motivation, and performance goals. No significant influence on mastering goals was found. Actual-ideal discrepancy uniquely correlates with depression symptom. The above results contribute from the point of self-discrepancy to the understanding of self-identity of undergraduates, and they enrich the knowledge of the development of self and contribute to the understanding of the development of human personality.This research advances on the two key problems of the developmental mechanism of actual-ideal discrepancy and that promotes the knowledge of the developmental mechanism of actual-ideal discrepancy. The research probed the relationship between the actual-ideal discrepancy and motivation which is an important phenomenon and this enlarges the domain of the actual-ideal discrepancy research. The results make sure that actual-ideal discrepancy is one of the important factors influencing undergruaduate’s mind and behavior. The conclusions can provide reference and guidance in the diagnosis and intervension strategies for mental health education and counseling practice in university.