Dynamics and manipulation of ferroelectric domain walls in bismuth ferrite thin films

Ferroelectric domain walls differ from domains not only in their crystalline and discrete symmetry, but also in their electronic, magnetic, and mechanical properties. Although domain walls provide a degree of freedom to regulate the physical properties at the nanoscale, the relatively lower controllability prevents their practical applications in nano-devices. In this work, with the advantages of 3D domain configuration detection based on piezoresponse force microscopy, we find that the mobility of three types of domain walls (tail-to-tail, head-to-tail, head-to-head) in (001) BiFeO₃ films varies with the applied electrical field. Under low voltages, head-to-tail domain walls are more mobile than other domain walls, while, under high voltages, tail-to-tail domain walls become rather active and possess relatively long average lengths. This is due to the high nucleation energy and relatively low growth energy for charged domain walls. Finally, we demonstrate the manipulation of domain walls through successive electric writings, resulting in well-aligned conduction paths as designed, paving the way for their application in advanced spintronic, memory and communication nano-devices.     

基于知识图谱的国内石墨烯研究分析与发展对策

以SCIE数据库中1994-2012年我国的石墨烯论文为研究对象,借助SCIE分析功能和信息可视化软件CiteSpace,对石墨烯文献进行计量和可视化分析。通过绘制知识图谱,展示了我国石墨烯研究的时间分布、空间分布、研究力量分布和主要研究领域,揭示了石墨烯的研究热点与应用领域,并就石墨烯研究的发展提出对策建议。     

从"政府企业家"到"市场企业家"——新常态下西部地区创新发展的策略转变

在中国经济高速增长的过程中,虽然各区域之间的差距始终存在,但缺乏内生动力的西部地区却并未陷入恶性循环,同样保持了较为快速的经济发展.由于市场中具备企业家精神的人才流失,长期以来,西部地区地方政府如企业家般直接干预经济,并依靠自身的企业家精神为区域经济发展引入大项目创新,实现了区域经济持续增长.然而在经济发展新常态下,这种经济发展策略由于政府可调配资源日益匮乏而逐渐失效;通过制度创新激发区域内市场中的企业家精神,从而实现大、中、小规模创新的协同发展,成为西部地区创新发展的策略选择.西部地区地方政府应科学制定发展目标,积极转变职能,通过制度创新更好地让市场发挥资源配置的决定性作用,从而有效激发出区域内的企业家精神.     

Initial Communication with and Attitudes toward International Students: Testing the Mediating Effects of Friendship Formation Variables

From the theoretical perspectives of intergroup contact, predicted outcome value (POV), and similarity-attraction, this study examined U.S. host nationals’ (N = 342) communicative behaviours in a recent initial encounter with an international student and attitudes toward the student’s cultural group as a whole. Testing of two models indicated the significant sequential mediator effects of perceived similarity-social attraction and POV-social attraction between communication variables (e.g. amount of communication exchange in both models, self-disclosure in model 1, and information seeking in model 2), and intergroup attitudes (e.g. behavioural attitudes). Findings in general demonstrated that contact effects in the intercultural context varied according to specific measures of communication, the mediating mechanisms, and intergroup attitudes.     

Emotional energy and sub-cultural politics: alternative bands in post-1997 Hong Kong

The paper attempts to work out the link between the structuring of the public domain and hegemonic masculinities in contemporary Kerala, South India. Using the debates around an incident of sexual harassment that happened in 1999, it argues for a conjunctural understanding of the contemporary where various events and moments in history are replayed through narrativization and popular memory. The paper goes on to analyse the debates around the incident that produce a ‘narrative public domain’, to foreground the various notions of masculinity that construct and structure it in relation to notions of female sexuality and changing structures of family. These notions of masculinity could be, the paper argues, a starting point for a historical inquiry into Kerala's modernity – an inquiry that would throw light on the past and the ways in which the contemporary is produced through its historical legacies.     

信息共享空间研究的知识图谱分析

以CSSCI数据库收录的以信息共享空间为主题的论文为基础数据,通过Citespace3.8R1软件对相关引文数据和主题词数据进行处理,绘制出信息共享空间领域的知识图谱,并对其进行分析,得出我国信息共享空间领域的重要学术文献及学术代表人物、主要研究热点及研究前沿等。     

0Cr18Ni9不锈钢车削力试验研究

切削力是切削加工中的一种伴随现象,切削力的大小直接影响到刀具寿命、加工质量和加工效率。在分析车削力时域特征的基础上,通过0Cr18Ni9不锈钢的正交车削试验,研究了切削参数对切削力波动系数的影响规律。结果表明：动态性是车削力的基本属性,切向分力和进给分力是车削力的主要成分;切削用量三要素中,切削深度ap对进给分力波动系数Qf和切向分力波动系数Qc都有着显著的影响,两者随ap的变化趋势基本一致。     

An efficient method of addressing ectopic beats: new insight into data preprocessing of heart rate variability analysis

Heart rate variability (HRV) analysis is affected by ectopic beats. An efficient method was proposed to deal with the ectopic beats. The method was based on trend correlation of the heart timing signal. Predictor of R-R interval (RRI) value at ectopic beat time was constructed by the weight calculation and the slope estimation of preceding normal RRI. The type of ectopic beat was detected and replaced by the predictor of RRI. The performance of the simulated signal after ectopic correction was tested by the standard value using power spectrum density (PSD) estimation, whereas the results of clinical data with ectopic beats were compared with the adjacent ectopic-free data. The result showed the frequency indexes after ectopy corrected had less error than other methods with the test of simulated signal and clinical data. It indicated our method could improve the PSD estimation in HRV analysis. The method had advantages of high accuracy and real time properties to recover the sinus node modulation.     

景区资源的低强度硬开发、高强度软开发与高强度保护

针对我国旅游景区第二轮大投资、大开发、大建设高潮中,在旅游资源开发、保护方面出现的矛盾与误区,本文提出了旅游资源"低强度硬开发、高强度软开发与高强度保护"的理念。旅游景区景物、交通、接待服务类土木工程硬开发越少越好,景观美、景物文化内涵、景区整体氛围等软开发越多越好。实施旅游资源高强度保护要点为:坚持以生态环境为导向,重视发挥政府规制作用,正确把握科学保护与开发利用的合理"度",积极鼓励与支持公众参与,正确引导游客消费。     

Longitudinal analysis of the environmental attitudes of university students

This article addresses the important questions that higher education institutions ask concerning their impact on their students’ sustainability-related attributes ‘How do our students’ worldviews change as they experience higher education with us?’ The process of monitoring such a dynamic entity is fraught with statistical complexity but may not be impossible for an institution willing to ask whether or not its educational efforts in ‘education for sustainability’, ‘education for sustainable development’ or ‘environmental education’, and campus sustainability developments, are paralleled by changes in the attitudes of its students. We describe here a longitudinal survey process based on the revised New Ecological Paradigm scale, with two cohorts of students, in three programmes of study, operating over four years, with multiple survey inputs by each student. We implemented the longitudinal analysis using a linear mixed-effects model and describe here the development and testing of this model. We conclude that higher education institutions can benchmark the sustainability attributes of their students and monitor changes, if they are minded to. We invite higher education practitioners worldwide to join us in further developing suitable research instruments, processes and statistical models, and in further analysing the assumptions that link higher education to sustainability and to global citizenship.