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961.
Organic–inorganic halide perovskites have recently been crowned as the leading next‐generation photovoltaic material due to their high efficiency and simple fabrication process. Herein, a low‐temperature‐processed CdS thin film (commonly used as a buffer layer in commercial CdTe or CIGSe solar cells) is reported as an electron selective layer in perovskite devices based on the following reasons: First, the photoelectric property of CdS thin film is investigated, illustrating the possibility of CdS as the electron selective layer in the application of methylammonium lead (II) iodide perovskite devices. More specifically, CdS semiconductor film presents a higher mobility compared with traditional TiO2 thin film, which benefits the electron extraction and transmission; second, it is found that the perovskite thin film spun‐coating on the CdS substrates grows with an obvious tendency along the direction toward the thickness of thin film, which reduces the chance of recombination of electrons and hole, beneficial to their separation. It is also revealed that the perovskite‐device‐based CdS electron selective layer has a higher stability compared with that of TiO2 due to the difference of substrates wetting. 相似文献
962.
工程建设过程、从业人员专业水平和信息存在较为突出的碎片化现象,导致了工程质量风险的传递。为揭示平行承发包模式下建设工程质量风险的传递效应和放大效应,利用传染病模型中的动力学原理,综合考虑工程质量风险传递的影响因素,构建了SEIRS的建设工程质量风险传递模型。仿真研究结果表明,建设工程在质量风险传递过程中存在阈值;质量风险传递阈值h1时,在质量风险传递阻碍因素的作用下,风险逐步衰减直至消失;质量风险传递阈值h<1时,在质量风险传递促进因素的作用下,风险会稳定存在于建设工程中,甚至危害工程的整体质量。研究结论为政府实现由直接监管向间接监管、由事前监管向事中事后监管的转变等提供理论支撑。 相似文献
963.
We reformulate the original component-by-component algorithm for rank- lattices in a matrix-vector notation so as to highlight its structural properties. For function spaces similar to a weighted Korobov space, we derive a technique which has construction cost , in contrast with the original algorithm which has construction cost . Herein is the number of dimensions and the number of points (taken prime). In contrast to other approaches to speed up construction, our fast algorithm computes exactly the same quantity as the original algorithm. The presented algorithm can also be used to construct randomly shifted lattice rules in weighted Sobolev spaces.
964.
Thomas Mattman Katura Miyazaki Kimihiko Motegi 《Transactions of the American Mathematical Society》2006,358(9):4045-4055
We construct two infinite families of knots each of which admits a Seifert fibered surgery with none of these surgeries coming from Dean's primitive/Seifert-fibered construction. This disproves a conjecture that all Seifert-fibered surgeries arise from Dean's primitive/Seifert-fibered construction. The -pretzel knot belongs to both of the infinite families.
965.
We analyze, using the optimal stopping theory, the entry-exit decision on a project, which takes time to be constructed and abandoned. We obtain the closed-form expressions of optimal start time of entry, optimal start time of exit, and the maximal expected present value of the project. In addition, we examine the effects of construction and abandonment periods on the optimal start times of entry and exit. 相似文献
966.
随着现代信息技术的迅猛发展,声音、图像、视频等多种媒体在课程教学中广为应用,学生在任何时间、任何地点利用信息终端完成线上自主学习成为常态,课程教学的信息全媒体时代随之而来,全媒体对实验教学带来全新要求。本文在总结近年来仪器分析实验全媒体教学经验的基础上,开展全媒体时代背景下仪器分析实验的实践教学设计、资源库建设、新型教学模式构建、课堂教学考评、教学团队建设的研究,以期提高学生自主综合学习能力和高阶思维能力,提升仪器分析实验课程的教学效果,为深入开展全媒体教学改革提供参考。 相似文献
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970.
Rustam Sadykov 《Proceedings of the American Mathematical Society》2005,133(3):931-936
The Pontrjagin-Thom construction expresses a relation between the oriented bordism groups of framed immersions , and the stable homotopy groups of spheres. We apply the Pontrjagin-Thom construction to the oriented bordism groups of mappings n$">, with mildest singularities. Recently, O. Saeki showed that for , the group is isomorphic to the group of smooth structures on the sphere of dimension . Generalizing, we prove that is isomorphic to the -th stable homotopy group , , where is the group of oriented auto-diffeomorphisms of the sphere and is the group of rotations of .