Impulsive synchronization and control of directed transport in chaotic ratchets

The impulsive synchronization problem of two identical chaotic ratchets is investigated in this paper. We demonstrate that the impulsive method to control directed transport is applicable when there are multiple co-existing attractors in phase space transporting particles in different directions. Numerical simulations are carried out to illustrate the effectiveness of the proposed method.     

A Novel Coupled Quantum Well Structure with Low-Driving Voltage, Low Absorption Loss and Large Field-Induced Refractive Index Change

Based on a two-energy-level system, we analyse the changing ground eigenenergies of symmetric CaAs/Alx Ca1-x As coupled quantum wells in the presence of an applied electric field. From the theoretical analysis for symmetric coupled quantum well, we find the advantages and disadvantages when it is applied to travelling wave modulator.Hence the conception of quasi-symmetric coupled quantum wells is put forward. Based on the demands of travelling wave modulator for quantum well materials, the configuration of quasi-symmetric coupled quantum well is further optimized. Consequently, in the case of low applied electric field (F=20 kV/cm) and low absorption loss (α≤100cm^-1), a large field-induced refractive change △n (for TE mode, △n = 0.021; for TM mode, △n=0.0121) is attained in the optimized coupled quantum well.     

Linear and nonlinear generalized consensuses of multi-agent systems

Consensus in directed networks of multiple agents, as an important topic, has become an active research subject. Over the past several years, some types of consensus problems have been studied. In this paper, we propose a novel type of consensus, the generalized consensus （GC）, which includes the traditional consensus, the anti-consensus, and the cluster consensus as its special cases. Based on the Lyapunov＇s direct method and the graph theory, a simple control algorithm is designed to achieve the generalized consensus in a network of agents. Numerical simulations of linear and nonlinear GC are used to verify the effectiveness of the theoretical analysis.     

新高考制度下开设大学物理预修课程的思考

在新一轮高考改革制度下, 高考物理出现学考和选考两种模式, 即高中毕业学生存在了物理知识的差 异性, 这为大学物理的教学带来新的挑战. 一方面通过问卷调查分析了本校高考学考和选考物理的比例及其成因; 另一方面, 针对新高考带来的物理知识的差异性, 提出了在本校开设大学物理预修课程的必要性和可行性, 并详细 分析该课程的教学目标、 课时设置、 教学模式等     

电场对Au—Ag薄膜结构影响的AFM和VAXPS研究

利用原子力显微镜（ＡＦＭ）和变角Ｘ射线光电子谱（ＶＡＸＰＳ）技术研究了Ａｕ－Ａｇ／ＳｉＯ２体系在直流电场作用下，Ａｕ，Ａｇ电迁移的特点及所引起的薄膜结构的变化，观察到较低温度下Ａｕ，Ａｇ聚集状态的显著变化，发现电迁移过程中Ａｕ－Ａｇ薄膜与ＳｉＯ２基底之间存在界面化学反应，膜层中Ａｕ，Ａｇ，Ｓｉ等元素的化学状态发生了相应的变化，这些结构表明ＳｉＯ２表面上Ａｕ－Ａｇ复合薄膜电迁移不只是一个水平方向的扩     

Signatures of strong interlayer coupling in γ-InSe revealed by local differential conductivity

Interlayer coupling in layered semiconductors can significantly affect their optoelectronic properties. However, understanding the mechanisms behind the interlayer coupling at the atomic level is not straightforward. Here, we study modulations of the electronic structure induced by the interlayer coupling in the γ-phase of indium selenide (γ-InSe) using scanning probe techniques. We observe a strong dependence of the energy gap on the sample thickness and a small effective mass along the stacking direction, which are attributed to strong interlayer coupling. In addition, the moiré patterns observed in γ-InSe display a small band-gap variation and nearly constant local differential conductivity along the patterns. This suggests that modulation of the electronic structure induced by the moiré potential is smeared out, indicating the presence of a significant interlayer coupling. Our theoretical calculations confirm that the interlayer coupling in γ-InSe is not only of the van der Waals origin, but also exhibits some degree of hybridization between the layers. Strong interlayer coupling might play an important role in the performance of γ-InSe-based devices.     

Alleviating hysteresis and improving device stability of perovskite solar cells via alternate voltage sweeps

The anomalous hysteresis in a perovskite solar cell induced by an asymmetric field is confirmed by a capacitance–voltage measurement. By applying several cycles of alternating reverse and forward scans, this hysteresis phenomenon is obviously alleviated, resulting in a hysteresis-less state in the perovskite solar cell. Meanwhile, the open-circuit voltage and power conversion efficiency of the perovskite solar cell are enhanced by 55.74% and 61.30%, respectively, while the current density and fill factor keep almost invariable. The operation of alleviating hysteresis is essential for further research and is likely to bring in performance gains.     

运用多种测试方法来分析英语学习中的错误

随着错误分析的不断发展,人们对错误分析的方法也越来越多。主要分析了在不同的测试方法下所反映出的语言错误,进而论证它对英语教学工作的启示,旨在使教学工作进一步地提高。     

述补格关系的检测及动偏补正质疑

述补格的偏正关系引起了学者的广泛关注,而且已达成了一些共识：部分动补格就是动偏补正的关系。通过对七类补语进行检测发现：述补格的关系并不简单。引发了对述补格中动偏补正关系的解读和质疑,以及对补语从属性的再论证。     

Tm3+/Yb3+共掺杂ZBLAN玻璃的多光子紫外上转换发光

利用光谱分析手段研究了熔融淬火法制备的Tm和Yb共掺杂的重金属氟化物玻璃ZrF4-BaF2-LaF3-AlF3-NaF的上转换发光性质.在980 nm连续激光的激发下,观察到了较强的363 nm(1D2→3H6),347nm(1I6→3F4)和291 nm(1I6→3H6)的紫外上转换发光,以及中心位于454 nm,4...