关键词： 水泥基复合材料   国际会议   结构相关   耐久性   美国国家标准与技术研究院   建筑科学研究院   东南大学   日本东京大学  

摘要： 由东南大学、荷兰代尔夫特理工大学、江苏省建筑科学研究院联合主办的＂第3届与微观结构相关的水泥基复合材料耐久性国际会议＂（The 3rd International Conference on Microstructure Related Durability of Cementitious Composite）于2016年10月24~26日在南京举行。会议汇集了来自中国、荷兰、美国、德国、法国、瑞士等20多个国家和地区包括加州大学伯克利分校、美国国家标准与技术研究院、瑞士洛桑联邦理工大学、日本东京大学，清华大学、浙江大学、东南大学在内的多所国内外知名高校与研究院所的共240余名专家和学者.

关键词： Viscoelastic   Composite materials   Finite element   Design   Beam   Plate  

摘要： An unstructured mesh Galerkin time domain finite element method is used to validate the effective viscoelastic stiffness predictions of the n-layered spherical inclusion model. We study composites consisting of a solid polymer matrix filled by core-shell inclusions made up of silica spheres coated with a viscoelastic polymer layer. Assuming temperature dependent properties of the coating layer, temperature runs are performed from below to above its glass transition region. The studied composites have a stiffness contrast from 30 to 3000 and coating layer thicknesses between 1 and 0.001 relative to the sphere radius. Periodic random Monte Carlo computer models with 27 non-overlapping identical core-shell spheres are employed in the finite element calculations. It is shown that the n-layered spherical inclusion model is remarkably accurate and suitable for quick and reliable microstructural design of viscoelastic composites with layered spherical inclusions. Damped natural vibrations of viscoelastic Bernoulli-Euler beams and Kirchhoff plates are considered and, using the viscoelastic corresponding principle, a refined figure of merit for selecting best performing materials for structural noise and vibration damping applications is derived. We perform optimum vibration damping time design and demonstrate that by optimizing the thickness and the properties of the coating layers, substantial improvements can be achieved in the vibration damping characteristics of viscoelastic beams and plates. (C) 2017 Elsevier Ltd. All rights reserved.

关键词： 微加工技术   光电材料   眩光抑制   LED照明  

摘要： 本文报道了用于LED照明的防眩光装置初步开发结果。基于微加工技术,通过光学传输模型和图像处理算法模拟,设计出基于薄层有机聚合物光电材料的三维结构,对常用的挤出、热压和转印生产工艺进行优化,实现了低成本、高性能、高效率的眩光抑制薄膜材料的批量生产,打破了市面上眩光抑制材料需要进口的局限。该产品可用于LED面板灯具,有利于创造出舒适安全的照明环境。

关键词： Carbon fibres   Damage tolerance   Crack   Scanning electron microscopy (SEM)   Biomimetics  

摘要： In this paper, a bio-inspired carbon-fibre/epoxy composite with nacre-like tiled microstructure is designed, synthesised and tested. Analytical models are developed to predict the energy dissipation and crack deflection properties of such composite, and the predictions for the stress-strain response during tile pull-out are validated against direct numerical simulation. Suitable configurations for tile geometry with interlocks are then identified (with dimensions of the order of 0.6 mm) and used for the subsequent prototyping. In-situ three-point bend tests are then carried out in a SEM environment, showing the capability of the interlocking micro-structure in deflecting the crack, avoiding sudden failure in the most highly loaded cross-section of the specimen. The results suggest that further damage diffusion could in principle be achieved by additionally modifying the interface between tiles. (C) 2017 Elsevier Ltd. All rights reserved.

关键词： ZnAl2O4纳米颗粒   机械力化学   超声波化学   固相反应  

摘要： 将机械力化学与超声波化学相结合制备出高纯度、结晶性良好的尖晶石型ZnAl_2O_4纳米颗粒。分析了样品的表面形貌、晶体结构及微观结构。研究结果表明:当焙烧温度为600~900℃时,ZnO与γ-Al_2O_3固相反应制备出高纯度、结晶性良好的尖晶石型ZnAl_2O_4纳米颗粒。随着焙烧温度的升高,材料的致密度增大,结晶度提高,平均孔径依次增大,比表面积明显下降,孔隙率降低。

关键词： W-La2O3   D-2 irradiation   He irradiation   He bubble  

摘要： A dispersion-strengthened W alloy, W-La2O3, was developed by spark plasma sintering (SPS). The D-2 retention and microstructural evolution under 5-keV He irradiation at high temperatures were investigated. Although the density of the W-La2O3 alloy was lower than that of commercially available W, the D2 retention did not change significantly. In addition, the D2 thermal desorption peak, which did not appear in commercial W, appeared at similar to 700 K due to the dissociation from D to vacancy clusters. In W-La2O3, the formation of He bubbles was observed at 773 K, 973 K and 1173 K. As the irradiation temperature was increased, void swelling also increased. For the same temperature, the formation of He bubbles was easier for W-La2O3 than for commercial W. This is considered to be the cause of low density of W-La2O3. W-La2O3 had a higher density of vacancies before He irradiation. The suppression of vacancy aggregation induced by the dispersion of La2O3 as the second phase appeared only at a high irradiation doses. (C) 2017 Elsevier B.V. All rights reserved.

关键词： PHASE transformations (Physics)   MICROSTRUCTURE   EUTECTIC alloys   INTERFACES (Physical sciences)   KIRKENDALL effect  

摘要： The coarsening behavior of three-phase materials, such as eutectic alloys, is of high technological interest. In this study, 3D ternary three-phase polycrystalline materials were modeled to study the effect of bulk diffusion and phase arrangement on the coarsening kinetics. The diffusion mobilities were defined to be different in the three phases. By varying the phase boundary and grain boundary energies, microstructures with different phase arrangements were obtained, in which the different types of grains had a tendency to alternate or cluster. In all cases, a regime was reached where the average grain size follows a power growth law with growth exponent , indicating bulk diffusion-controlled coarsening. The overall growth rate and that of the individual phases were clearly affected by the phase arrangement, the magnitude of the phase boundary energy and the diffusion mobilities of the different phases. In all cases, the phase with the lowest diffusion mobility showed the highest growth rate and on average a larger number of grain faces. While the average number of grain faces became constant in time in systems with constant grain boundary energy, the average number of grain faces continued to increase during the whole simulation time when the grain boundary energy was misorientation dependent.

关键词： Industrial applications   adsorb   macro commands   food systems   LOW MOLECULAR WEIGHT   liquids  

摘要： The mechanism of adsorbing particles in creating super stable bubbles has been underlined and described but designing particles with these characteristics based of food grade materials is still a challenge. Moreover, food systems are rarely "pure" and the presence of more than one functional ingredients at a given formulation is usually the norm. This highlights the importance of mixed systems where particles and surface active ingredients are present. It has been demonstrated that particles made from food based materials although often not able to stabilised foams on their own, mostly due to limitations in size and hydrophobicity, they can aid significantly in the stability of foams without their ability to adsorb on the interface being a limiting factor. Evidence is presented where particles made from protein (whey) and hydrocolloid (k-carageenan) sources can significantly extend the life of foams by affecting the rheological properties of these systems in both a macro and micro level. The technology of creating fluid gels poses an advantage in the production of these particles in a scalable manner that can provide solutions for industrial applications that demand liquid and powder formulations. The importance of surfactants (high or low molecular weight) that are either intrinsically present or added in the systems is also being underlined. Finally, a universal mechanism is proposed which allows the design of particulate systems from soft-solid materials that can produce edible liquid foams with enhanced stability. (C) 2017 The Authors. Published by Elsevier Ltd.

关键词： Microstructure   Optical materials and properties   Photonic crystal   Band gap   Topology optimization  

摘要： We propose a new approach to design photonic crystals (PhCs) with large complete photonic band gaps (CPBGs). By superposing two specific photonic structures with independent TE and TM band gaps, a heuristic design with CPBG is created. Then the CPBG is maximized using topology optimization method. This design method is verified for both square and hexagonal lattices, and several innovative structures with wide CPBGs are obtained. One of them presents the largest ever reported CPBG in 2D PhCs. The geometric characteristics of these innovative designs are discussed. (C) 2017 Elsevier B.V. All rights reserved.

关键词： 金属玻璃复合材料   剪切带   微结构   数值模拟   颗粒  

摘要： 通过数值模拟研究了块体金属玻璃复合材料(BMGCs)在压缩破坏时的微结构效应,分别讨论了颗粒体积分数、颗粒尺寸、颗粒形貌、颗粒团聚和热残余应力对金属玻璃复合材料压缩韧性的影响。在模拟过程中,使用等效塑性应变作为一个内部状态变量,通过剪切破坏准则来描述BMGCs中剪切带的诱发、演化和主剪切带的形成过程,利用单元删除技术描述剪切带到微裂纹的转变过程。数值模拟结果显示上述因素都对剪切带的形成和发展有不同程度的阻碍效应,从而影响了BMGCs的压缩增韧效果。上述工作将有助于理解金属玻璃的破坏机理和BMGCs的增韧设计。