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61.
Michele Vacatello 《Macromolecular theory and simulations》2003,12(1):86-91
Monte Carlo computer simulations have been performed for model polymers containing randomly distributed spherical filler particles (20% in volume) with diameter between 4 times and 28 times the transverse diameter of the chains. By analyzing the results in conjunction with those of previous simulations, a few simple rules are deduced allowing to predict approximately the molecular arrangements in these complex systems.
62.
J.E. Mark 《Macromolecular Symposia》2003,201(1):77-84
There are number of important developments in the area of elastomeric polymers, including (i) network chains of controlled stiffness, (ii) model elastomers (including dangling-chain networks), (iii) fluorosiloxane elastomers, (iv) new thermoplastic elastomers, (v) other new elastomers, (v) bimodal network chain-length distributions, (vi) cross linking in solution or in a state of deformation, and (vii) gel collapse. Interesting elastomeric composites include those with (i) in-situ generated ceramic-like particles, (ii) ellipsoidal fillers, (iii) clay-like layered fillers, (iv) polyhedral oligomeric silsesquioxane (POSS) particles, (v) porous fillers, (vi) elastomeric domains modifying ceramics, and (vii) controlled interfaces. New characterization techniques are being developed for elastomers, and there have been new developments in elasticity theory and in elastomer processing. Some examples of societal aspects of relevance are (i) synthesis of elastomers in environmentally-friendly solvents, (ii) biosynthesis, (iii), recyclability, (iv) improved adhesion to tire cords, and (v) better barrier properties in anti-terrorism clothing. Educational topics include curriculum development, and mobile laboratories for elastomer experiments and demonstrations. 相似文献
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正交异性钢桥面板纵肋与顶板连接细节处极易产生疲劳裂纹.本文通过精细化有限元模型,分析了栓接角钢加固法和粘贴纤维增强复合材料(Fiber Reinforced Polymer, FRP)型材加固法对钢桥面板疲劳性能的影响.结果表明:采用角钢、FRP型材对顶板与纵肋连接细节的疲劳裂纹进行加固,焊缝裂纹附近热点应力峰值降幅可达56.2%和46.5%;焊缝裂纹尖端附近应力强度因子随着板件整体尺寸的增大而减小;改变板件厚度对应力强度因子结果值影响最大,最高可使其下降约80%,改变板件纵向长度和单肢长度对其有一定影响;随着裂纹的持续扩展,栓接角钢法的加固效果开始下降.建议在监测到构造细节处疲劳裂纹后应尽早加固. 相似文献
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Jeongho Park Juwon Lee Taehwan Kim Inkyung Ahn Jooyoung Park 《Entropy (Basel, Switzerland)》2021,23(4)
The problem of finding adequate population models in ecology is important for understanding essential aspects of their dynamic nature. Since analyzing and accurately predicting the intelligent adaptation of multiple species is difficult due to their complex interactions, the study of population dynamics still remains a challenging task in computational biology. In this paper, we use a modern deep reinforcement learning (RL) approach to explore a new avenue for understanding predator-prey ecosystems. Recently, reinforcement learning methods have achieved impressive results in areas, such as games and robotics. RL agents generally focus on building strategies for taking actions in an environment in order to maximize their expected returns. Here we frame the co-evolution of predators and preys in an ecosystem as allowing agents to learn and evolve toward better ones in a manner appropriate for multi-agent reinforcement learning. Recent significant advancements in reinforcement learning allow for new perspectives on these types of ecological issues. Our simulation results show that throughout the scenarios with RL agents, predators can achieve a reasonable level of sustainability, along with their preys. 相似文献
68.
不同于混凝土材料,钢筋混凝土(RC)构件的破坏模式与机制更为复杂,采用混凝土材料尺寸效应理论难以描述构件的尺寸效应行为。我国相关规范中并没有系统考虑构件尺寸及纵筋率对RC梁抗剪承载力的影响。为研究剪跨比及纵筋率对无腹筋RC梁剪切破坏及抗剪强度尺寸效应的影响,采用三维细观数值模拟方法,建立了RC梁剪切破坏力学分析模型,研究了剪跨比及纵筋率对RC梁剪切破坏及抗剪强度尺寸效应的影响机制与规律。研究结果表明,RC梁抗剪强度表现出极为显著的尺寸效应现象;RC梁抗剪强度随剪跨比的增大而减小,随纵筋率的增大而增大;剪跨比较小时,纵筋率对抗剪强度的影响尤为显著。此外,基于Ba■ant材料层次尺寸效应律,提出了考虑剪跨比及纵筋率影响的RC梁抗剪强度尺寸效应理论公式。对比试验结果,验证了所提公式的准确性与合理性。 相似文献
69.
Adeleke A. Oyekanmi N. I. Saharudin Che Mohamad Hazwan Abdul Khalil H. P. S. Niyi G. Olaiya Che K. Abdullah Tata Alfatah Deepu A. Gopakumar Daniel Pasquini 《Molecules (Basel, Switzerland)》2021,26(8)
Hydrophilic behaviour of carrageenan macroalgae biopolymer, due to hydroxyl groups, has limited its applications, especially for packaging. In this study, macroalgae were reinforced with cellulose nanofibrils (CNFs) isolated from kenaf bast fibres. The macroalgae CNF film was after that treated with silane for hydrophobicity enhancement. The wettability and functional properties of unmodified macroalgae CNF films were compared with silane-modified macroalgae CNF films. Characterisation of the unmodified and modified biopolymers films was investigated. The atomic force microscope (AFM), SEM morphology, tensile properties, water contact angle, and thermal behaviour of the biofilms showed that the incorporation of Kenaf bast CNF remarkably increased the strength, moisture resistance, and thermal stability of the macroalgae biopolymer films. Moreover, the films’ modification using a silane coupling agent further enhanced the strength and thermal stability of the films apart from improved water-resistance of the biopolymer films compared to unmodified films. The morphology and AFM showed good interfacial interaction of the components of the biopolymer films. The modified biopolymer films exhibited significantly improved hydrophobic properties compared to the unmodified films due to the enhanced dispersion resulting from the silane treatment. The improved biopolymer films can potentially be utilised as packaging materials. 相似文献
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