基于模因理论唤醒对传统外语教学模式的再认识

研究模因与语言模因及其在传统外语教学中的体现和运用,分析模因论对英语教学带来的新挑战,使我们进一步认识到:在模因论指导下的传统外语教学模式在现代外语教学中应当给予足够的重视,只有将传统的教学模式和现代的教学模式相结合才是具有中国特色的外语教学。     

Magnetically encoded 3D mesostructure with high-order shape morphing and high-frequency actuation

Inspired by origami/kirigami, three-dimensional (3D) mesostructures assembled via a mechanics-guided approach, with reversible and maneuverable shape-morphing capabilities, have attracted great interest with regard to a broad range of applications. Despite intensive studies, the development of morphable 3D mesostructures with high-order (multi-degree-of-freedom) deformation and untethered high-frequency actuation remains challenging. This work introduces a scheme for a magnetically encoded transferable 3D mesostructure, with polyethylene terephthalate (PET) film as the skeleton and discrete magnetic domains as actuation units, to address this challenge. The high-order deformation, including hierarchical, multidirectional and blending shape morphing, is realized by encoding 3D discrete magnetization profiles on the architecture through ultraviolet curing. Reconfigurable 3D mesostructures with a modest structural modulus (∼3 GPa) enable both high-frequency (∼55 Hz) and large-deformation (∼66.8%) actuation under an alternating magnetic field. Additionally, combined with the shape-retention and adhesion property of PET, these 3D mesostructures can be readily transferred and attached to many solid substrates. On this basis, diverse functional devices, including a switchable colour letter display, liquid mixer, sequential flashlight and biomimetic sliding robot, are demonstrated to offer new perspectives for robotics and microelectronics.     

Recent progress in reactivity study and synthetic application of N-heterocyclic phosphorus hydrides

N-heterocyclic phosphines (NHPs) have recently emerged as a new group of promising catalysts for metal-free reductions, owing to their unique hydridic reactivity. The excellent hydricity of NHPs, which rivals or even exceeds those of many metal-based hydrides, is the result of hyperconjugative interactions between the lone-pair electrons on N atoms and the adjacent σ^*(P–H) orbital. Compared with the conventional protic reactivity of phosphines, this umpolung P–H reactivity leads to hydridic selectivity in NHP-mediated reductions. This reactivity has therefore found many applications in the catalytic reduction of polar unsaturated bonds and in the hydroboration of pyridines. This review summarizes recent progress in studies of the reactivity and synthetic applications of these phosphorus-based hydrides, with the aim of providing practical information to enable exploitation of their synthetically useful chemistry.     

复杂混合网络中拥塞控制算法仿真实验设计

拥塞控制是计算机网络课程中的一个重点和难点.文章通过引入NS3网络仿真工具,对构建复杂混合网络实验环境的方法和步骤进行了论述,并在4∶4哑铃网络拓扑结构的基础上,实现了多个网络实验场景;以拥塞窗口大小为依据,对常见的多种拥塞控制算法进行了理论验证性实验;以吞吐量为依据,对同类拥塞控制算法之间的公平性和异类拥塞控制算法之...     

财政补贴、融资约束与高端装备制造企业研发投入

选取2010-2017年我国高端装备制造业上市公司的微观数据,考察财政补贴、融资约束与企业研发投入之间的关系.研究结果表明:财政补贴对高端装备制造企业的研发投入强度具有显著的促进作用,且这种促进作用在国有企业、年轻型企业和成长型企业中更明显;而融资约束不仅直接对高端装备制造企业的研发投入强度产生抑制作用,还抑制财政补贴...     

The histone H3K27 demethylase REF6/JMJ12 promotes thermomorphogenesis in ArabidopsisOA

Dynamic trimethylation of histone H3 at Lys27(H3 K27 me3) affects gene expression and controls plant development and environmental responses.In Arabidopsis thaliana,RELATIVE OF EARLY FLOWERING 6(REF6)/JUMONJI DOMAIN-CONTAINING PROTEIN 12 demethylates H3 K27 me3 by recognizing a specific DNA motif.However,little is known about how REF6 activates target gene expression after recognition,especially in environmental responses.In response to warm ambient temperature, plants undergo thermomorphogenesi...     

典型小额信贷模式分析及对我国小额信贷实践的启示

小额信贷作为一种新型的金融方式,在一些发展中国家所取得的成效是举世公认的。但小额信贷自上世纪90年代初至今在中国二十多年的发展,一直不尽如人意。本文希望通过对两种典型小额信贷模式的分析,与我国小额信贷实践相比较,探讨对我国小额信贷实践发展的启示。     

基于灰色模糊理论的核心专利识别方法研究

针对现有核心专利识别方法在指标选定及权重判定方面较为单一的不足,利用布拉德福定律及灰色模糊理论提出一套技术领域核心专利识别方法.首先,通过技术应用区域、主要IPC、主要研究机构及3D专利地图等4个维度的分析,了解相应技术的发展状态;其次,运用布拉德福定律确定核心专利的数量,并从技术、法律、市场的角度构建指标体系,运用灰...     

国际经济与贸易专业人才培养方案的研究与改革

本文在探讨普通高校国际经济与贸易专业培养目标与规格及其定位依据的基础上,构建了该专业以素质教育为主线,以能力培养为重点,以“三大融合”为特色,使受教育者的知识、能力和素质全面协调发展的人才培养模式。     

研发驱动内生增长模型中的企业研发行为与政府政策

在研发驱动的内生经济增长理论的框架内,对企业研发竞争行为和政府研发政策的最新研究进展进行了深入探讨,并结合我国产业现状指出政府为产业领先者提供补贴并对新的产业领先企业的利润征税能使社会福利达到最优。