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排序方式: 共有555条查询结果,搜索用时 15 毫秒
61.
Behnam B. Malakooti Ying Q. Zhou Evan C. Tandler 《Journal of Intelligent Manufacturing》1995,6(1):53-66
The authors develop a monitoring and supervising system for machining operations using in-process regressions (for monitoring) and adaptive feedforward artificial neural networks (for supervising). The system is designed for: (1) in-process tool life measurement and prediction; (2) supervision of machining operations in terms of the best machining setup; and (3) catastrophic tool failure monitoring. The monitoring system predicts tool life by using different sensors for gathering information based on a regression model that allows for the variations between tools and different machine setups. The regression model makes its prediction by using the history of other tools and combining it with the information obtained about the tool under consideration. The supervision system identifies the best parameters for the machine setup problem within the framework of multiple criteria decision making. The decision maker (operator) considers several criteria, such as cutting quality, production rate and tool life. To make the optimal decision with several criteria, an adaptive feedforward artificial neural network is used to assess the decision maker's preferences. The authors' neural network approach learns from the decision maker's complex behavior and hence, in automatic mode, can make decisions for the decision maker. The approach is not computationally demanding, and experiments demonstrate that its predictions are accurate. 相似文献
62.
Russell F. Mizell III James L. Frazier T. Evan Nebeker 《Journal of chemical ecology》1984,10(1):177-187
Tree volatiles and pheromones produced by southern bark beetles were bioassayed for response by the clerid predatorThanasimus dubius (F.). Upwind flights in a laboratory olfactometer, modified from Visser (1976), were used to determine the attractiveness of compounds. Differences in response to a solvent control and pheromone treatment were tested for statistical significance using the Wilcoxon signed ranks test. Both sexes ofT. dubius responded to frontalin, ipsdienol, and -pinene in a dose-dependent manner with different but overlapping concentration ranges. Strong differences between the sexes were observed in response totrans-verbenol, verbenone, andl--pinene. Neither sex responded to ipsenol orendo-brevicomin.Miss. Agric. and For. Exp. Sta. Publication No. 5251. 相似文献
63.
Evan F. Koenig 《Energy》1981,6(5):457-470
We examine three alternative methods by which electric utilities might take advantage of distributed thermal energy storage to smooth out their load profiles. These three methods are: (1) time-specific rates, (2) time-invariant rates with subsidized storage, and (3) direct load controls with no subsidies to storage. The optimal form of each of these policies is determined and relations indicating the relative desirability of each are developed. 相似文献
64.
Computer simulation of structure and properties of crosslinked polymers: application to epoxy resins 总被引:1,自引:0,他引:1
In this work, a methodology has been developed for construction of atomistic models of crosslinked polymer networks. The methodology has been applied to low molecular weight water soluble epoxy resins crosslinked with different curing agents that are being considered for use as a primer coating on steel. The simulations allowed the crosslink density and the amount of free crosslinking sites in the coatings to be predicted. Shrinkage of the resin upon curing was reproduced by the simulation. In addition, the barrier properties of the model coatings were estimated. The interface between an inorganic substrate and cured epoxy resin has been constructed and the strength and molecular mechanisms of adhesion have been revealed. The developed methodology has a potential to significantly impact on the design and development of new coatings with improved barrier and adhesion properties. 相似文献
65.
Previous studies show that if acoustic startle stimuli are presented in pairs, then the reaction to the 2nd stimulus (S2) is reduced, with the size of the refractory decrement determined by the interstimulus interval and the relative intensity of the 1st stimulus (S1). If a neutral stimulus (p) is presented just prior to S1, then the reaction to S1 is similarly inhibited, revealing the phenomenon of prestimulus inhibition. In 2 experiments with male albino Holtzman rats (N = 24) it was found that suppression of the reflex to S2 by S1 was unaffected by prestimulus inhibition of S1 (i.e., reflex amplitudes associated with S2 were identical in pS1-S2 series and S1-S2 series). In contrast, a reduction in the intensity of S1 relative to S2 did reduce the effect of S1 on S2. These data indicate that prestimulus inhibition of the reflex to S1 does not result because the preliminary stimulus attenuates the sensory impact of S1. The inhibitory process may be presumed to have a central locus. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
66.
Leischow Scott J.; Valente Suzanne N.; Hill Anabel L.; Otte Pamela S.; Aickin Mikel; Holden Timothy; Kligman Evan; Cook Gretchen 《Canadian Metallurgical Quarterly》1997,5(1):54
The effects of using several different nicotine replacement treatments on self-reported withdrawal symptoms and side effects during 2-day periods of smoking cessation, with 5 days of ad lib smoking between cessation days, were evaluated. Participants (N ?=?18) experienced the following conditions: nicotine gum, 24-hr patch, 16-hr patch, 24-hr patch plus gum, double 24-hr patch, and no nicotine replacement. The present study found morning urge to smoke was greater during the 16-hr than during the 24-hr patch condition. Double-patch use resulted in significantly greater insomnia than the smoking baseline and 16-hr patch conditions. The no medication and gum alone conditions resulted in similar withdrawal symptoms, and both tended to result in greater reported withdrawal symptoms than the smoking baseline condition. There were no significant withdrawal symptom differences between the 24-hr, patch-gum, and double-patch conditions. The 24-hr and double-patch conditions were preferred by two thirds of the participants (6 each). (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
67.
Nasim Mia Kuljeet Singh James Polson Luciano Lisi Evan Willemsen Yulin Hu 《加拿大化工杂志》2024,102(2):585-606
Hydrogen (H2) is a clean energy carrier widely used in oil refineries, fertilizers, chemicals, and steel manufacturing. Presently, the majority of H2 is produced from either steam methane reforming of natural gas or coal gasification; however, these technologies result in a massive amount of CO2 emission. Alternatively, the use of photocatalysts for producing H2 via water splitting is an eco-friendly and sustainable approach, among which the selection of highly efficient, stable, and cheap photocatalysts is the key. In this review, Znln2S4-based photocatalysts are thoroughly described in terms of the fundamentals and thermodynamics of water splitting, fabrication methods, and different heterostructure photocatalytic systems. After this, recent developments in the large-scale implementation of photocatalytic reactors are discussed. Finally, a summary of future research directions and major conclusions is provided. With proper modification, such as heterojunction systems and the selection of proper fabrication methods, Znln2S4-based photocatalysts could be superior materials for water splitting. In short, this review article could offer meaningful and useful insights and guidance for the development of Znln2S4-based photocatalysts in water splitting for producing H2 under visible light. 相似文献
68.
What can we learn from the spatial logic of collections of trees in the rainforest? Evan Greenberg of the EmTech programme at the Architectural Association (AA) School of Architecture in London and George Jeronimidis of the Centre for Biomimetics at the University of Reading combine forces to analyse the rainforest's morphology and its potential as an urban model. They suggest how the sectional height differentiation of trees could present a new way of thinking about urban organisation, accommodating varied microclimates, programmes and the city's infrastructural flows. 相似文献
69.
70.
Evan J. Telford Avalon H. Dismukes Kihong Lee Minghao Cheng Andrew Wieteska Amymarie K. Bartholomew Yu-Sheng Chen Xiaodong Xu Abhay N. Pasupathy Xiaoyang Zhu Cory R. Dean Xavier Roy 《Advanced materials (Deerfield Beach, Fla.)》2020,32(37):2003240
The recent discovery of magnetism within the family of exfoliatable van der Waals (vdW) compounds has attracted considerable interest in these materials for both fundamental research and technological applications. However, current vdW magnets are limited by their extreme sensitivity to air, low ordering temperatures, and poor charge transport properties. Here the magnetic and electronic properties of CrSBr are reported, an air-stable vdW antiferromagnetic semiconductor that readily cleaves perpendicular to the stacking axis. Below its Néel temperature, TN = 132 ± 1 K, CrSBr adopts an A-type antiferromagnetic structure with each individual layer ferromagnetically ordered internally and the layers coupled antiferromagnetically along the stacking direction. Scanning tunneling spectroscopy and photoluminescence (PL) reveal that the electronic gap is ΔE = 1.5 ± 0.2 eV with a corresponding PL peak centered at 1.25 ± 0.07 eV. Using magnetotransport measurements, strong coupling between magnetic order and transport properties in CrSBr is demonstrated, leading to a large negative magnetoresistance response that is unique among vdW materials. These findings establish CrSBr as a promising material platform for increasing the applicability of vdW magnets to the field of spin-based electronics. 相似文献