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941.
Many models of spoken word recognition posit the existence of lexical and sublexical representations, with excitatory and inhibitory mechanisms used to affect the activation levels of such representations. Bottom-up evidence provides excitatory input, and inhibition from phonetically similar representations leads to lexical competition. In such a system, long words should produce stronger lexical activation than short words, for 2 reasons: Long words provide more bottom-up evidence than short words, and short words are subject to greater inhibition due to the existence of more similar words. Four experiments provide evidence for this view. In addition, reaction-time-based partitioning of the data shows that long words generate greater activation that is available both earlier and for a longer time than is the case for short words. As a result, lexical influences on phoneme identification are extremely robust for long words but are quite fragile and condition-dependent for short words. Models of word recognition must consider words of all lengths to capture the true dynamics of lexical activation. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
942.
Amphetamine and cocaine dependence present significant public health concerns, yet no broadly effective pharmacotherapy for stimulant dependence has been developed. Two human laboratory studies are reviewed that tested the ability of aripiprazole, a novel antipsychotic with partial agonist activity at D2 dopamine receptors, to alter the behavioral effects of stimulants using d-amphetamine as a model agent. In each of these experiments, volunteers learned to discriminate 15 mg d-amphetamine (i.e., ≥80% drug-appropriate responding over 4 consecutive sessions). The effects of a range of doses of d-amphetamine (0, 2.5, 5, 10, and 15 mg) were then tested alone and following pretreatment with aripiprazole (20 mg in Experiment 1; 10 mg in Experiment 2). In Experiment 1, aripiprazole (20 mg) attenuated the discriminative stimulus and many of the subject-rated effects of amphetamine. Aripiprazole alone produced performance decrements. To determine whether a lower dose of aripiprazole would also attenuate the behavioral effects of d-amphetamine without impairing performance, Experiment 2 was conducted. Aripiprazole (10 mg) failed to alter the discriminative-stimulus effects but attenuated some of the subject-rated effects of d-amphetamine. This dose of aripiprazole did not impair performance. The results of these experiments indicate that aripiprazole may have clinical utility in treating stimulant dependence. Future human laboratory research should better model the clinical use of aripiprazole by examining the effects of chronic aripiprazole combined with either methamphetamine or cocaine in dependent individuals. A large-scale clinical trial is also needed to evaluate the efficacy of aripiprazole for the treatment of stimulant dependence. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
943.
This note proposes a simple linear matrix inequality (LMI) system for the design of static precompensators to reduce the interactions of a multivariable system. The approach is based on minimizing the H2 norm of a modified system and the LMIs are derived from the well known technique of pseudodiagonalisation. The approach is applied to two complex real-life benchmark problems with high levels of interaction. It is shown that its performance is significantly better than previously proposed LMI optimization techniques for designing static precompensators 相似文献
944.
P. B. Lovyrev A. I. Lavrov V. A. Babkin A. N. Aminov S. M. Melekhin Yu. P. Kazantsev P. M. Korol’kov 《Metallurgist》2006,50(3-4):152-157
Specifications require that all the welds in 12-m-diam. decomposers with a capacity of 3600 m3 be subjected to high-temperature tempering before going into service in order to alleviate the stresses from the welding
operation. Specialists at the organizations VNIIPTkhimnefteapparatury and VNIImontazhspetsstroi have proposed out-of-furnace
volumetric (complete) of the assembled decomposer with the use of special heaters. The use of this heating method has shortened
assembly operations while providing the welds with a highquality heat treatment and reducing the stresses overall (including
welding stresses, stresses from assembly of the decomposer, etc.) The technology ensures uniform heating of the housing of
the decomposer and provides for close control over the process. The experience gained in heat-treating decomposers can also
be used in the construction of other containers that come into contact with corrosive media.
__________
Translated from Metallurg, No. 3, pp. 61–64, March, 2006. 相似文献
945.
The Chelyabinsk Metallurgical Combine has periodically used Kachkanar agglomerate to make conversion pig iron since 1972.
Use of this material reached a peak in 1998, when it comprised an average of 27.1% of the charge. In some months, the amount
of this material charged into the furnace reached highs of 45.6 and 74.1% on certain furnaces. The coolers on the iron notches
of furnaces 4 and 5 burned during that year, the quality of the smelting products and the condition of the ladles rapidly
deteriorated, and the smelting rate declined. No Kachkanar agglomerate was used in 2000–2001, but it was again added to the
charge in February 2002. The amount used was smaller than previously, averaging 10.7% for the shop as a whole. It was determined
that using a charge with 15% Kachkanar agglomerate has both positive and negative consequences.
N. N. Gorshkov, A. V. Denisov, and V. Kh. Barinov also participated in this study.
__________
Translated from Metallurg, No. 3, pp. 43–45, March, 2006. 相似文献
946.
Reports an error in "Tradeoffs and Theory: The Double-Mediation Model" by Marc Scholten and Steven J. Sherman (Journal of Experimental Psychology: General, 2006 May, Vol 135[2], 237-261). This article was inadvertently printed with the incorrect title. The original title was "Tradeoffs and Conflict: The Double-Mediation Model." This title highlights the relation between tradeoffs and conflict as investigated by the authors and accounted for by their model. However, readers are asked to refer to the article by the title with which it was printed to facilitate its retrieval.. (The following abstract of the original article appeared in record 2006-06642-006.) Most theories of decision making suggest that, when options imply tradeoffs between their attributes, conflict increases as tradeoff size increases, because greater sacrifices are to be incurred in choosing one option instead of another. An alternative view is that conflict decreases as tradeoff size increases, because stronger arguments can be made for any decision. The authors propose a unified model, the double-mediation model, which combines the mediating effects of sacrifice and argumentation. Our model generally predicts an inverse U-shaped relation between tradeoff size and conflict. Results support this prediction. Also, when the decision situation increases the mediating effect of sacrifice relative to that of argumentation, the relation between tradeoff size and conflict changes in an upward direction; conversely, when the decision situation increases the mediating effect of argumentation relative to that of sacrifice, the relation changes in a downward direction. Results support these predictions as well. Commonalities and differences between our model and other formulations are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
947.
B. Schönfelder G. Gottstein L. S. Shvindlerman 《Metallurgical and Materials Transactions A》2006,37(6):1757-1771
While the motion of twist boundaries can be readily studied by atomistic simulations with molecular dynamics (MD) under the
action of an elastic driving force, the approach fails for tilt boundaries. This is due to the interaction of the elastic
stress with the grain boundary (GB) structure, which causes plastic strain by GB sliding. A novel concept, the orientation
correlated driving force, is introduced to circumvent this problem. It is shown that this concept can be successfully applied
to the study of the migration of tilt boundaries. The migration behavior of several twist and tilt GBs was investigated. The
transition from low-to high-angle boundaries can be captured, and a structural transition of tilt boundaries was found at
high temperatures, which also affected the migration behavior. The results compare well with experimental results of the motion
high-angle boundaries, but for low-angle boundaries, the agreement is poor.
This article is based on a presentation made in the “Hillert Symposium on Thermodynamics & Kinetics of Migrating Interfaces
in Steels and Other Complex Alloys,” December 2–3, 2004, organized by The Royal Institute of Technology in Stockholm, Sweden. 相似文献
948.
Finite element analysis of problems in structural and geotechnical engineering results in linear systems where the unknowns are displacements and rotations at nodes. Although the solution of these systems can be carried out using either direct or iterative methods, in practice the matrices involved are usually very large and sparse (particularly for 3D problems) so an iterative approach is often advantageous in terms of both computational time and memory requirements. This memory saving can be further enhanced if the method used does not require assembly of the full coefficient matrix during the solution procedure. One disadvantage of iterative methods is the need to apply preconditioning to improve convergence. In this paper, we review a range of established element-based preconditioning methods for linear elastic problems and compare their performance with a new method based on preconditioning with element displacement components. This new method appears to offer a significant improvement in performance. 相似文献
949.
Simulation is useful for evaluating protocol performance and operation. However, the lack of rigor with which it's applied threatens the credibility of the published research within the manet research community. Mobile ad hoc networks (manets) allow rapid deployment because they don't depend on a fixed infrastructure. Manet nodes can participate as the source, the destination, or an intermediate router. This flexibility is attractive for military applications, disaster-response situations, and academic environments where fixed net working infrastructures might not be available. 相似文献
950.
V. A. Babenko V. V. Grigor’yants I. P. Shilov 《Journal of Communications Technology and Electronics》2006,51(6):618-630
Basic definitions related to the main electrodynamic characteristics of surface space-charge waves are formulated. These characteristics and their relationships with the geometric dimensions of guiding structures (a dielectric cylinder and a planar metal-dielectric waveguide) are determined. 相似文献