Fluid dynamics: an emerging route for the scalable production of graphene in the last five years

Bulk applications of graphene in fields such as advanced composites, conductive ink, and energy storage require cheap and scalable graphene. Fortunately, in the last decade, liquid-phase exfoliation of graphite to give pristine graphene has been thought as a promising way to massive production of graphene at high efficiency and low cost, in terms of the cheap and abundant graphite source and a variety of cost-effective exfoliation techniques. Though many exfoliation techniques are available so far, this article will highlight the recent progress of fluid dynamics route which emerges as a promising scalable and efficient way for graphene production in the last five years. The emphasis is set on vortex fluidic devices and pressure- and mixer-driven fluid dynamics, with our perspectives on the latest progress, exfoliation mechanism, and some key issues that require further study in order to realize industrial applications.Comment: 18 figure

Pure Exporter: Theory and Evidence

This paper provides the first evidence about pure exporters (i.e., firms exporting all of their output to the foreign market) -- a phenomenon overlooked and cannot be explained in the existing literature. It then offers a generalized model of Melitz (2003) for examining the existence and behavior of pure exporters. In particular, pure exporters arise when the export market is sufficiently large -- a situation more likely to hold in developing countries as opposed to large developed countries; and their productivity levels are above those of non-exporters, but below those of firms having both domestic sales and export. These theoretical predictions are borne out in a data of Chinese manufacturing firms for the period of 1998-2005.Pure Exporter, Firm Heterogeneity, Exporting Behavior

Learning-by-Teaching in CS Education: A Systematic Review

To investigate the strategies and approaches in teaching Computer Science (CS), we searched the literature review in CS education in the past ten years. The reviews show that learning-by-teaching with the use of technologies is helpful for improving student learning. To further investigate the strategies that are applied to learning-by-teaching, three categories are identified: peer tutoring, game-based flipped classroom, and teachable agents. In each category, we further searched and investigated prior studies. The results reveal the effectiveness and challenges of each strategy and provide insights for future studies

Spectrum to distance mapping via nonlinear Airy pulses

We theoretically and experimentally study the phenomena related to self-phase modulation of Airy pulses in fibers. During nonlinear evolution, most spectral components of the Airy pulses concentrate into one or two peaks for normal and anomalous dispersion, respectively. The resulting peaks self-shift along the propagation, effectively mapping the longitudinal coordinate into the frequency domain. The frequency shift can be precisely controlled by simply acting on the spectral cubic phase structure without the need to alter the fiber length