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A highly supersaturated nanocrystalline Cr–25?wt% Zr alloy has been prepared by mechanical alloying of elemental crystalline powders. High-purity powders of Cr and Zr were milled for up to 20?h. The development of the microstructure was investigated by X-ray diffraction (XRD) and scanning electron microscopy. XRD patterns confirmed complete alloying of the Zr and Cr. The contribution of grain boundaries, the chemical potential of a solute atom induced by dislocations, and the elastic strain energy arising from the different sizes of Cr and Zr atoms have been calculated. The alloy formation is discussed with respect to the thermodynamic conditions of the material. The role of internal strains and stored enthalpies by dislocations on solute atoms is the major mechanical driving force for alloying and this is critically assessed in this article. 相似文献
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Savaş Sönmezoğlu Yakup Ulusu Fatma Gedikli Özlem Ateş Sönmezoğlu İsa Gökçe 《Philosophical Magazine Letters》2013,93(5):211-216
We have fabricated a molecular organic light-emitting device comprising indium–tin oxide/a molecular organic layer/aluminum in which the organic layer is a green fluorescent protein. The device exhibits peak external quantum and power efficiencies of 8?±?0.2% and 13?±?0.7?lm?W???1 at a current of J?=?1.5?A?m?2, respectively. In addition, the turn-on voltage is 2.5?V for 1?cd?m?2 and the maximum luminance achieved is 1275?cd?m?2. This good performance can be explained by the presence of singlet-excited states, leading to a high internal efficiency. 相似文献
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Hamed Hatami-Marbini 《Philosophical Magazine Letters》2016,96(5):165-174
Random fibre networks have unique mechanical properties and appear as the primary building blocks of many biological and structural materials. Although fibre networks are usually three-dimensional in nature, prior studies have mainly used simplistic two-dimensional models to characterize their properties. The present study creates a 3D strain-based nonaffinity measure and investigates the mechanical behaviour and scaling properties of 3D fibre networks. This measure is used to fully examine the influence of primarily characteristic length scales, i.e. mean segment length and bending length, on nonaffine mechanical behaviour of 3D filamentous networks. It is observed that all nonaffinity measure components exhibit a power-law variation with the probing length scale. Furthermore, it is found that while the degree of nonaffinity in both 2D and 3D systems decreases with increasing the probing length scale, the two power-law scaling regimes previously reported for 2D networks do not appear in 3D. 相似文献
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认知匹配策略和形式匹配策略的实验研究 总被引:7,自引:0,他引:7
将用以调节学生学习心向的两条教材内容的情感性处理策略——认知匹配策略和形式匹配策略分别运用于语文和外语教学中,进行现场教学实验研究。研究结果表明:分别运用这两条策略对教材内容进行情感性处理,对调节学生的学习心向,促进学生的认知和情感学习、提高课堂教学质量是可行而有效的。 相似文献
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骨缺损是临床上的常见病,也是骨科治疗的难题之一。近年来,骨组织工程发展迅速,利用骨组织工程治疗骨缺损成为研究的热点。组织工程应用的主要问题在于种子细胞的培养和细胞种植基质材料的优化。在此领域的发展过程中,渗透着丰富的哲学思想,理解和把握这些哲学思想对完善利用骨组织工程治疗骨缺损的工作将大有益处。 相似文献
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An ABAB experimental design was used to evaluate the effects of access to recreational activities contingent on the completion of at least 80% of academic tasks assigned daily. Requirements in four task categories (writing, copying words, spelling, and dictionary skills) were specified daily and students were required to complete at least 80% of the requirements in each category correctly in order to participate in daily recreational activities. The procedure produced reliable and educationally important increases in the task performance of all 19 third-grade students in the study. Most of the difference in the performance of each child between experimental conditions was on the spelling and dictionary tasks, although there were also improvements on the writing and words-copied tasks for those students showing the greatest overall change in performance. The procedure was easily implemented by the teacher alone, required only materials and equipment typically found in elementary schools, and produced changes in performance important enough to the teacher that she continued to use the basic procedure after the evaluation program was terminated. 相似文献
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教材内容的情感性分析及其处理策略 总被引:25,自引:3,他引:25
人们对教材的教学心理学分析研究相对较少,仅有的也多囿于认知维度。奥苏贝尔在其意义学习理论框架下研究了教材的意义性及其学习条件问题,并提出了著名的处理教材内容的先行组织者策略,然其研究仍属认知维度。其实,教材也是构成教学中情感现象的一个重要源点,对其进行情感性分析研究,将有助于从情感维度系统优化教学。故本文对教材内容进行较系统的情感分析,归纳为蕴涵显性、隐性、悟性和中性情感因素的四大类,并在教学实验 相似文献
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发掘情感策略的实验研究 总被引:7,自引:0,他引:7
将对内含隐性情感因素的教材内容实施情感性处理的一种策略——发掘情感策略运用于语文教学,进行现场的教学实验研究。研究结果表明:在内含隐性情感因素的文科教材内容中,可以运用发掘情感策略来对其进行情感性处理;这对促进学生的认知学习和情感发展、提高课堂教学质量是有效的。 相似文献
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Masahiko Nishijima Makoto Matsuura Yan Zhang Akihiro Makino 《Philosophical Magazine Letters》2015,95(5):277-284
Microstructure of a nanocrystalline soft magnetic Fe85Si2B8P4Cu1 alloy (NANOMET®) was investigated by the state of the art spherical aberration-corrected TEM/STEM. Observation by TEM shows that the microstructure of NANOMET® heat treated at 738 K for 600 s which exhibits the optimum soft magnetic properties has homogeneously distributed bcc-Fe nanocrystallites with the average grain size of 30 nm embedded in an amorphous matrix. Elemental mappings indicate that P is excluded from bcc-Fe grains and enriched outside the grains, which causes to retard the grain growth of bcc-Fe crystallites. The aberration-corrected STEM-EDS analysis with the ultrafine electron probe successfully proved that Cu atoms form nanometre scale clusters inside and/or outside the bcc-Fe nanocrystallites. 相似文献