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951.
952.
Gian Luigi Angrisani Piriya Taptimthong Susanne Elisabeth Thürer Christian Klose Hans Jürgen Maier Marc Christopher Wurz Kai Möhwald 《Advanced Engineering Materials》2018,20(9)
953.
He Zhu Qiang Li Yang Ren Qilong Gao Jun Chen Na Wang Jinxia Deng Xianran Xing 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(13)
The efficiency of gas sensors varies enormously from fundamental study to practical application. This big gap comes mainly from the complex and unpredictable effect of atmospheric environment, especially in humidity. Here, the cross‐sensitivity to humidity of a SnO2 sensor from local structural and lattice evolutions is studied. The sensing response of ethanol is found to be efficiently activated by adsorbing trace of water but inhibited as humidity increases. By X‐ray diffraction, pair distribution function of synchrotron and ab initio calculations, the independent effect of water and ethanol on lattice and local structure are clearly revealed, which elucidate the intricate sensing reactions. The formation of hydrogen bonds and repulsion of ethoxides play key roles in the structural distortions, and also in adsorption energies that are critical to the sensitive behavior. The results show the sensor performance coupled with local structural evolution, which provides a new insight into the controversial effects of humidity on SnO2 sensors. 相似文献
954.
目的 归纳隔热疏水涂料的功能实现方法,分析疏水隔热功能涂料在包装中的潜在的应用价值,为新型多功能涂料的制备及其在纸包装领域的应用提供参考和借鉴。方法 梳理并归纳阻隔型、反射型、辐射型等3种类型隔热涂料的工作原理及实现方式,系统介绍几种常见的疏水表面形成机理模型以及制备方法,综述疏水隔热功能涂料的应用研究进展。结果 涂料的制备以及涂布技术已经成熟,疏水隔热功能涂料可涂布于瓦楞纸箱、白卡纸等表面用于食品保温包装。结论 将隔热疏水功能涂料用于纸包装箱,用来保护温敏食品品质和节约冷链运输成本,具有巨大的潜力和广阔的发展前景。 相似文献
955.
热轧板带加热过程中高温氧化将直接影响氧化铁皮的结构、元素分布以及粘附性,进而间接影响后续除鳞效果以及粗轧和精轧后得到的成品钢板表面质量。本文利用Gleeble热模拟试验机模拟Q345B连铸坯粗轧前在1 150和1 250℃加热阶段的氧化情况,并结合拉伸试验研究了两个温度下氧化铁皮的表面形貌、次生氧化铁皮的裂纹以及氧化铁皮与基体界面处截面形貌和各合金的元素分布。研究表明:高温短时氧化生成的一次氧化铁皮粘附性小,仅微小变形即可完全剥离脱落;次生氧化铁皮粘附性大,但强度低,塑性差,易产生裂纹。此外,次生氧化铁皮与基体界面处反应生成的Fe2SiO4会改变氧化铁皮FeO内层的相间分布,对氧化皮起到钉扎作用,导致氧化皮的粘附性强,这增大了后续除鳞的难度。为改善钢板的表面质量,生产实践中建议在粗轧除鳞前控制钢板氧化铁皮界面温度高于Fe2SiO4凝固温度,以降低氧化铁皮与钢板基体附着力。 相似文献
956.
Ceramic foams are made of zinc oxide using different amounts of Sb2O3 and Bi2O3 as sintering aids. The effect of a ball milling processing of the starting powders and the sintering temperature on the microstructure and the properties of the ZnO foams is investigated. The focus is set on the evolution of the secondary phases formed within the microstructure of ZnO. A determining effect is identified in the amount of an Al2O3 impurity which is introduced by abrasion of the milling vessels during ball milling. Alumina is partially dissolved in a spinel α–Zn7Sb2O12 secondary phase which is stabilized by a reduction of the unit cell volume. Remaining Al2O3 is incorporated into zinc oxide under formation of a defect wurtzite phase. The phase evolution is a complex function of the content of sintering aids, the Al2O3 impurity level and the sintering temperature. The shrinkage during sintering and the porosity evolution are correlated to the phase composition within the ZnO material. The thermal conductivity and the compressive strength of the foams are determined, normalized with respect to their porosity, and correlated to the microstructure and phase composition of the ZnO strut material. 相似文献
957.
Hybrid chiral mechanical metamaterials with center squares connecting by bi-layer strips (bi-strips) with patterned interfaces are designed and fabricated via multimaterial 3D printing. Due to the thermal mismatch between the bi-strips and the chirality-induced rotation, the designs will undergo either thermal expansion or shrinkage under constant temperature increase, resulting in widely tuned overall thermal expansion coefficients (CTEs) for the chiral mechanical metamaterials. Analytical models of both the bi-strips with arbitrary dissimilar interface morphology and the chiral designs under temperature change are developed to predict the curvature of the bi-strips and the overall CTEs of the chiral designs. Two design regions with opposite trends are observed and explored. The models are verified via systematic finite element (FE) simulations and experiments on 3D-printed specimens. This investigation enlarges the design space of chiral mechanical metamaterials for achieving desired CTEs in a wide range. 相似文献
958.
Chongzhen Du Chuanzhen Huang Shijie Li Hanlian Liu 《Advanced Engineering Materials》2023,25(20):2300564
The design of the lamination structure based on bionic shell pearl layer is a successful method for toughening ceramics. Lamination with strong bonding interfaces is used to improve the mechanical property and low fracture toughness of ceramic cutting tools. Based on the idea of demand–design–preparation–analysis–failure, the development and research progress of laminated ceramic tools are reviewed herein. The research status of design, interlayer diffusion reaction, residual stress, toughening mechanism, and crack propagation path of the biomimetic laminated ceramic composite tool materials is mainly introduced. The major topics of current research include the creation of material systems, the evolution of microstructure, and the assessment of macroscopic mechanical properties. The entire mechanical properties of laminated ceramic tools are significantly influenced by the multicomposition design of the ceramic material system and the optimization design of structural parameters of layer number and layer thickness ratio. However, the research on the practical cutting application of laminated ceramic tools is limited. Cutting tool wear characteristics vary between laminated and homogeneous ceramic tools. The development of useful laminated ceramic cutting tools can greatly benefit from the study on failure mechanisms of laminated ceramic tools. 相似文献
959.
Merle Schmahl Cecilia Müller Reinhard Meinke Erika G. Alves Alcantara Ude D. Hangen Claudia Fleck 《Advanced Engineering Materials》2023,25(10):2201676
Cyclic nanoindentation allows characterizing the influence of single phases and their interactions on fatigue mechanisms. Herein, a method for high cycle fatigue testing by nanoindentation is presented. By combining high- and low-frequency indentation modes, high cycle numbers are achieved while obtaining sufficient data points to reconstruct force–displacement hysteresis loops. A challenge is the stochastic course of thermal drift which is addressed by measuring drift rate in regular low-force holding segments. Drift rates are used to correct the displacement values, yielding reproducible cyclic deformation data as it is shown for two very different materials, a ductile metal and a brittle ceramic. 相似文献
960.
丁小中 《土木与环境工程学报》1998,20(5):10-15
描述蓄水屋机的演变过程,推荐隔热效果最优化的浮盖式方案,提出蓄水屋顶动态襄减的新见解,分析影响衰减的主要因素。 相似文献