There exist several honeycomb networks exhibiting zero Poisson's ratio (ZPR). Applications of these networks can be found in different fields. The ZPR properties of these structures have been mechanically modeled ...
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There exist several honeycomb networks exhibiting zero Poisson's ratio (ZPR). Applications of these networks can be found in different fields. The ZPR properties of these structures have been mechanically modeled and tested. However, the underlying mechanism driving the ZPR behavior has not been paid much attention. The present work focuses on the deformation mechanism of the ZPR networks. Through the discussion and comparison of the deformation process of the ZPR, auxetic and common honeycomb networks, the strain-isolation mechanism is proposed to explain the ZPR behavior. Then, according to this mechanism, the reversed semi-re-entrant (RSRE) honeycomb is created. With experimental measurements and finite-element analysis (FEA), the ZPR properties of the RSRE can be proven. The strain-isolation mechanism can not only explain the ZPR behavior but also be used in the design of new ZPR honeycomb networks. 3D ZPR structures are also derived from the 2D honeycomb networks. Their Poisson's ratios in 3D space are also discussed based on FEA results. (C) 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
In allusion to the deficiencies existing in current structural optimization algorithm of excavator boom such as the inefficiency in expressing and handling the constraints, the insufficiency in adopting the task knowl...
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ISBN:
(纸本)9783037853726
In allusion to the deficiencies existing in current structural optimization algorithm of excavator boom such as the inefficiency in expressing and handling the constraints, the insufficiency in adopting the task knowledge to direct constraint handling, and the difficulty in obtaining and adopting the optimal process knowledge, a new method of the constraints expression and handling based on cultural algorithm for excavator boom structural optimization is put forward. The mechanism of hierarchical constraints expression and handing is established to improve the efficiency of the constraint handling in the optimal process with the cultural algorithm as frame and the task knowledge as guide. And the hierarchical topographical knowledge is formed to express tacit knowledge in the population space. Then the process of constraints expressing and handling as well as its interaction with the knowledge base is discussed under the direction of dual evolution in cultural algorithm while the aim of acquisition, expression and handling for tacit constraints knowledge in optimal process is realized. Finally, structural optimization of an excavator boom is taken as an example to demonstrate the effectiveness of this method.
Tryptophan and arginine rich antimicrobial peptides (AMPs) possess high potencies against both gram positive and gram negative bacteria, while lipopeptides represent another family of promising antimicrobial agents to...
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Tryptophan and arginine rich antimicrobial peptides (AMPs) possess high potencies against both gram positive and gram negative bacteria, while lipopeptides represent another family of promising antimicrobial agents to combat invading pathogens. In the present study, we have synthesized a series of very short arginine, lysine and tryptophan containing lipopeptides and evaluated their antimicrobial activities against a panel of pathogenic microorganisms including Staphylococcus aureus, Escherichia colt, and Candida albicans. The results showed that most of these peptides were effective against tested strains with MIC values ranging from 3.9 to 62.5 mu g/mL. In addition to the small size, potent bactericidal activity, low to moderate hemolytic toxicity and membrane disruption ability, several peptides such as C10-RIKWWK and C10-RKWWK apparently retarded the migration of DNA on agarose gel in the DNA-binding assay, which implied the multiple modes of action in their bacteria-killing mechanism. These peptides revealed a promising therapeutic potential to develop as new antimicrobial agents. (C) 2014 Elsevier Masson SAS. All rights reserved.
Psychophysical experiments have been carried out in which the color appearance of high-gloss and low-gloss color printing atlases was assessed using a magnitude estimation method under three different light sources. A...
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The geometric error of machine axis can be equivalent to the differential movement, regarded as a differential operator based on its ideal position. Thus, a new modeling method for multi-axis CNC machines based on dif...
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MK-4256, a tetrahydro-beta-carboline sstr3 antagonist, was discontinued due to a cardiovascular (CV) adverse effect observed in dogs. Additional investigations revealed that the CV liability (QTc prolongation) was cau...
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MK-4256, a tetrahydro-beta-carboline sstr3 antagonist, was discontinued due to a cardiovascular (CV) adverse effect observed in dogs. Additional investigations revealed that the CV liability (QTc prolongation) was caused by the hERG off-target activity of MK-4256 and was not due to sstr3 antagonism. In this Letter, we describe our extensive SAR effort at the C3 position of the tetrahydro-beta-carboline structure. This effort resulted in identification of 5-fluoro-pyridin-2-yl as the optimal substituent on the imidazole ring to balance sstr3 activity and the hERG off-target liability. (C) 2016 Elsevier Ltd. All rights reserved.
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