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81.
In the design process of gratings, the grating layout design is the most important activity influencing manufacturing cost. In the grating layout design, the key to saving manufacturing cost is to find a design with a minimal number of cutting operations. This paper presents an application of the A* algorithm in grating layout design. The design problem is represented as the space search problem of design alternatives. A* explores the feasible alternatives within the space, until an optimal solution is obtained. 相似文献
82.
J. Cho 《Journal of Materials Science》1994,29(15):3993-3996
The thermal decomposition and crystallization processes of two types of films with various thicknesses prepared by spin-coating aqueous and acetylacetonic solutions made by dissolving metal nitrate hydrates of appropriate ratios for the garnets, are described. It was found that the aqueous films decomposed with endothermic reactions over a broad temperature range from 80–500 °C, while the acetylacetonic films decomposed at two strong exothermic reactions at temperatures of 130 °C and 250 °–400 °C. Both films decomposed to become amorphous oxides, which then began to crystallize at a temperature of about 600 °C. It was also found that when the amorphous oxide films were thinner than 0.3 m, the garnets were formed directly from the amorphous oxides. When the films were thicker than 0.3 m, intermediate orthoferrites were formed which, upon further heating, transformed to the garnets. Differential thermal analysis, thermogravimetry, and X-ray diffraction data in the temperature range 20–750 °C are given and discussed. 相似文献
83.
Seong-Hwan Cho Afshin Karshenas Akhtarhusein A. Tayebali Murthy N. Guddati 《International Journal of Pavement Engineering》2017,18(12):1098-1110
The debonding distress in asphalt pavement structures is a critical problem that affects the performance of asphalt concrete pavements. It occurs at the layer interface due to the poor bond quality between adjacent asphalt concrete layers and/or when stresses at the layer interface exceed the strengths of the material at the interface. The debonding of the adjacent layers, especially the top surface layer of an asphalt pavement, is a contributing factor to the premature cracking of pavements. Hence, the debonding distress can lead to a reduction in the life of the pavement. This paper presents an analytical and experimental framework to evaluate the potential for debonding at the layer interface of asphalt concrete pavements. Computational analysis was performed to determine the critical stress and strain states in layered asphalt pavements under moving vehicle loads using the Layered ViscoElastic pavement analysis for Critical Distresses (LVECD) computer program developed at North Carolina State University. This computational analysis enables a greater understanding of the critical stress that is involved in debonding and the ways that such stress is affected by pavement design parameters and environmental conditions. In addition, a prediction model was developed that can determine the shear bond strength at the interface of asphalt concrete layers with different tack coat materials at various temperatures, loading rates and normal confining stresses. The systematic and mechanistic framework developed in this study employs the maximum shear ratio concept as a shear failure criterion and provides a tool to evaluate the effects of various loading, environmental and pavement factors on the debonding potential of asphalt pavements. The overall advantages of the mechanistic framework and approach using the LVECD analysis tool will help lead to better understanding of the debonding mechanism, proper selection of the tack coats, and economic benefit in highway pavement maintenance and rehabilitation costs. 相似文献
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85.
Designing Metallic and Insulating Nanocrystal Heterostructures to Fabricate Highly Sensitive and Solution Processed Strain Gauges for Wearable Sensors 下载免费PDF全文
Woo Seok Lee Seung‐Wook Lee Hyungmok Joh Mingi Seong Haneun Kim Min Su Kang Ki‐Hyun Cho Yun‐Mo Sung Soong Ju Oh 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(47)
All‐solution processed, high‐performance wearable strain sensors are demonstrated using heterostructure nanocrystal (NC) solids. By incorporating insulating artificial atoms of CdSe quantum dot NCs into metallic artificial atoms of Au NC thin film matrix, metal–insulator heterostructures are designed. This hybrid structure results in a shift close to the percolation threshold, modifying the charge transport mechanism and enhancing sensitivity in accordance with the site percolation theory. The number of electrical pathways is also manipulated by creating nanocracks to further increase its sensitivity, inspired from the bond percolation theory. The combination of the two strategies achieves gauge factor up to 5045, the highest sensitivity recorded among NC‐based strain gauges. These strain sensors show high reliability, durability, frequency stability, and negligible hysteresis. The fundamental charge transport behavior of these NC solids is investigated and the combined site and bond percolation theory is developed to illuminate the origin of their enhanced sensitivity. Finally, all NC‐based and solution‐processed strain gauge sensor arrays are fabricated, which effectively measure the motion of each finger joint, the pulse of heart rate, and the movement of vocal cords of human. This work provides a pathway for designing low‐cost and high‐performance electronic skin or wearable devices. 相似文献
86.
Tissue Engineering: Effective Light Directed Assembly of Building Blocks with Microscale Control (Small 24/2017) 下载免费PDF全文
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88.
Solar Cells: Multidimensional Anodized Titanium Foam Photoelectrode for Efficient Utilization of Photons in Mesoscopic Solar Cells (Small 34/2017) 下载免费PDF全文
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